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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
fbb9ce95 IM |
2 | /* |
3 | * kernel/lockdep.c | |
4 | * | |
5 | * Runtime locking correctness validator | |
6 | * | |
7 | * Started by Ingo Molnar: | |
8 | * | |
4b32d0a4 | 9 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
90eec103 | 10 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra |
fbb9ce95 IM |
11 | * |
12 | * this code maps all the lock dependencies as they occur in a live kernel | |
13 | * and will warn about the following classes of locking bugs: | |
14 | * | |
15 | * - lock inversion scenarios | |
16 | * - circular lock dependencies | |
17 | * - hardirq/softirq safe/unsafe locking bugs | |
18 | * | |
19 | * Bugs are reported even if the current locking scenario does not cause | |
20 | * any deadlock at this point. | |
21 | * | |
22 | * I.e. if anytime in the past two locks were taken in a different order, | |
23 | * even if it happened for another task, even if those were different | |
24 | * locks (but of the same class as this lock), this code will detect it. | |
25 | * | |
26 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
27 | * mapping lock dependencies runtime. | |
28 | */ | |
a5e25883 | 29 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
30 | #include <linux/mutex.h> |
31 | #include <linux/sched.h> | |
e6017571 | 32 | #include <linux/sched/clock.h> |
29930025 | 33 | #include <linux/sched/task.h> |
6d7225f0 | 34 | #include <linux/sched/mm.h> |
fbb9ce95 IM |
35 | #include <linux/delay.h> |
36 | #include <linux/module.h> | |
37 | #include <linux/proc_fs.h> | |
38 | #include <linux/seq_file.h> | |
39 | #include <linux/spinlock.h> | |
40 | #include <linux/kallsyms.h> | |
41 | #include <linux/interrupt.h> | |
42 | #include <linux/stacktrace.h> | |
43 | #include <linux/debug_locks.h> | |
44 | #include <linux/irqflags.h> | |
99de055a | 45 | #include <linux/utsname.h> |
4b32d0a4 | 46 | #include <linux/hash.h> |
81d68a96 | 47 | #include <linux/ftrace.h> |
b4b136f4 | 48 | #include <linux/stringify.h> |
ace35a7a | 49 | #include <linux/bitmap.h> |
d588e461 | 50 | #include <linux/bitops.h> |
5a0e3ad6 | 51 | #include <linux/gfp.h> |
e7904a28 | 52 | #include <linux/random.h> |
dfaaf3fa | 53 | #include <linux/jhash.h> |
88f1c87d | 54 | #include <linux/nmi.h> |
a0b0fd53 | 55 | #include <linux/rcupdate.h> |
2f43c602 | 56 | #include <linux/kprobes.h> |
af012961 | 57 | |
fbb9ce95 IM |
58 | #include <asm/sections.h> |
59 | ||
60 | #include "lockdep_internals.h" | |
61 | ||
a8d154b0 | 62 | #define CREATE_TRACE_POINTS |
67178767 | 63 | #include <trace/events/lock.h> |
a8d154b0 | 64 | |
f20786ff PZ |
65 | #ifdef CONFIG_PROVE_LOCKING |
66 | int prove_locking = 1; | |
67 | module_param(prove_locking, int, 0644); | |
68 | #else | |
69 | #define prove_locking 0 | |
70 | #endif | |
71 | ||
72 | #ifdef CONFIG_LOCK_STAT | |
73 | int lock_stat = 1; | |
74 | module_param(lock_stat, int, 0644); | |
75 | #else | |
76 | #define lock_stat 0 | |
77 | #endif | |
78 | ||
fbb9ce95 | 79 | /* |
74c383f1 IM |
80 | * lockdep_lock: protects the lockdep graph, the hashes and the |
81 | * class/list/hash allocators. | |
fbb9ce95 IM |
82 | * |
83 | * This is one of the rare exceptions where it's justified | |
84 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 85 | * code to recurse back into the lockdep code... |
fbb9ce95 | 86 | */ |
edc35bd7 | 87 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
cdc84d79 | 88 | static struct task_struct *lockdep_selftest_task_struct; |
74c383f1 IM |
89 | |
90 | static int graph_lock(void) | |
91 | { | |
0199c4e6 | 92 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
93 | /* |
94 | * Make sure that if another CPU detected a bug while | |
95 | * walking the graph we dont change it (while the other | |
96 | * CPU is busy printing out stuff with the graph lock | |
97 | * dropped already) | |
98 | */ | |
99 | if (!debug_locks) { | |
0199c4e6 | 100 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
101 | return 0; |
102 | } | |
bb065afb SR |
103 | /* prevent any recursions within lockdep from causing deadlocks */ |
104 | current->lockdep_recursion++; | |
74c383f1 IM |
105 | return 1; |
106 | } | |
107 | ||
108 | static inline int graph_unlock(void) | |
109 | { | |
0119fee4 PZ |
110 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
111 | /* | |
112 | * The lockdep graph lock isn't locked while we expect it to | |
113 | * be, we're confused now, bye! | |
114 | */ | |
381a2292 | 115 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 116 | } |
381a2292 | 117 | |
bb065afb | 118 | current->lockdep_recursion--; |
0199c4e6 | 119 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
120 | return 0; |
121 | } | |
122 | ||
123 | /* | |
124 | * Turn lock debugging off and return with 0 if it was off already, | |
125 | * and also release the graph lock: | |
126 | */ | |
127 | static inline int debug_locks_off_graph_unlock(void) | |
128 | { | |
129 | int ret = debug_locks_off(); | |
130 | ||
0199c4e6 | 131 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
132 | |
133 | return ret; | |
134 | } | |
fbb9ce95 | 135 | |
fbb9ce95 | 136 | unsigned long nr_list_entries; |
af012961 | 137 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
ace35a7a | 138 | static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES); |
fbb9ce95 | 139 | |
fbb9ce95 IM |
140 | /* |
141 | * All data structures here are protected by the global debug_lock. | |
142 | * | |
a0b0fd53 BVA |
143 | * nr_lock_classes is the number of elements of lock_classes[] that is |
144 | * in use. | |
fbb9ce95 | 145 | */ |
108c1485 BVA |
146 | #define KEYHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) |
147 | #define KEYHASH_SIZE (1UL << KEYHASH_BITS) | |
148 | static struct hlist_head lock_keys_hash[KEYHASH_SIZE]; | |
fbb9ce95 | 149 | unsigned long nr_lock_classes; |
1431a5d2 BVA |
150 | #ifndef CONFIG_DEBUG_LOCKDEP |
151 | static | |
152 | #endif | |
8ca2b56c | 153 | struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; |
01bb6f0a | 154 | static DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS); |
fbb9ce95 | 155 | |
a3a49a17 | 156 | inline struct lock_class *lockdep_hlock_class(struct held_lock *hlock) |
f82b217e | 157 | { |
01bb6f0a YD |
158 | unsigned int class_idx = hlock->class_idx; |
159 | ||
160 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfield */ | |
161 | barrier(); | |
162 | ||
163 | if (!test_bit(class_idx, lock_classes_in_use)) { | |
0119fee4 PZ |
164 | /* |
165 | * Someone passed in garbage, we give up. | |
166 | */ | |
f82b217e DJ |
167 | DEBUG_LOCKS_WARN_ON(1); |
168 | return NULL; | |
169 | } | |
01bb6f0a YD |
170 | |
171 | /* | |
172 | * At this point, if the passed hlock->class_idx is still garbage, | |
173 | * we just have to live with it | |
174 | */ | |
175 | return lock_classes + class_idx; | |
f82b217e | 176 | } |
a3a49a17 SF |
177 | EXPORT_SYMBOL_GPL(lockdep_hlock_class); |
178 | #define hlock_class(hlock) lockdep_hlock_class(hlock) | |
f82b217e | 179 | |
f20786ff | 180 | #ifdef CONFIG_LOCK_STAT |
25528213 | 181 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
f20786ff | 182 | |
3365e779 PZ |
183 | static inline u64 lockstat_clock(void) |
184 | { | |
c676329a | 185 | return local_clock(); |
3365e779 PZ |
186 | } |
187 | ||
c7e78cff | 188 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
189 | { |
190 | int i; | |
191 | ||
c7e78cff PZ |
192 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
193 | if (points[i] == 0) { | |
194 | points[i] = ip; | |
f20786ff PZ |
195 | break; |
196 | } | |
c7e78cff | 197 | if (points[i] == ip) |
f20786ff PZ |
198 | break; |
199 | } | |
200 | ||
201 | return i; | |
202 | } | |
203 | ||
3365e779 | 204 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
205 | { |
206 | if (time > lt->max) | |
207 | lt->max = time; | |
208 | ||
109d71c6 | 209 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
210 | lt->min = time; |
211 | ||
212 | lt->total += time; | |
213 | lt->nr++; | |
214 | } | |
215 | ||
c46261de PZ |
216 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
217 | { | |
109d71c6 FR |
218 | if (!src->nr) |
219 | return; | |
220 | ||
221 | if (src->max > dst->max) | |
222 | dst->max = src->max; | |
223 | ||
224 | if (src->min < dst->min || !dst->nr) | |
225 | dst->min = src->min; | |
226 | ||
c46261de PZ |
227 | dst->total += src->total; |
228 | dst->nr += src->nr; | |
229 | } | |
230 | ||
231 | struct lock_class_stats lock_stats(struct lock_class *class) | |
232 | { | |
233 | struct lock_class_stats stats; | |
234 | int cpu, i; | |
235 | ||
236 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
237 | for_each_possible_cpu(cpu) { | |
238 | struct lock_class_stats *pcs = | |
1871e52c | 239 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
240 | |
241 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
242 | stats.contention_point[i] += pcs->contention_point[i]; | |
243 | ||
c7e78cff PZ |
244 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
245 | stats.contending_point[i] += pcs->contending_point[i]; | |
246 | ||
c46261de PZ |
247 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
248 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
249 | ||
250 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
251 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
252 | |
253 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
254 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
255 | } |
256 | ||
257 | return stats; | |
258 | } | |
259 | ||
260 | void clear_lock_stats(struct lock_class *class) | |
261 | { | |
262 | int cpu; | |
263 | ||
264 | for_each_possible_cpu(cpu) { | |
265 | struct lock_class_stats *cpu_stats = | |
1871e52c | 266 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
267 | |
268 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
269 | } | |
270 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 271 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
272 | } |
273 | ||
f20786ff PZ |
274 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
275 | { | |
01f38497 | 276 | return &this_cpu_ptr(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
277 | } |
278 | ||
279 | static void lock_release_holdtime(struct held_lock *hlock) | |
280 | { | |
281 | struct lock_class_stats *stats; | |
3365e779 | 282 | u64 holdtime; |
f20786ff PZ |
283 | |
284 | if (!lock_stat) | |
285 | return; | |
286 | ||
3365e779 | 287 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 288 | |
f82b217e | 289 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
290 | if (hlock->read) |
291 | lock_time_inc(&stats->read_holdtime, holdtime); | |
292 | else | |
293 | lock_time_inc(&stats->write_holdtime, holdtime); | |
f20786ff PZ |
294 | } |
295 | #else | |
296 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
297 | { | |
298 | } | |
299 | #endif | |
300 | ||
fbb9ce95 | 301 | /* |
a0b0fd53 BVA |
302 | * We keep a global list of all lock classes. The list is only accessed with |
303 | * the lockdep spinlock lock held. free_lock_classes is a list with free | |
304 | * elements. These elements are linked together by the lock_entry member in | |
305 | * struct lock_class. | |
fbb9ce95 IM |
306 | */ |
307 | LIST_HEAD(all_lock_classes); | |
a0b0fd53 BVA |
308 | static LIST_HEAD(free_lock_classes); |
309 | ||
310 | /** | |
311 | * struct pending_free - information about data structures about to be freed | |
312 | * @zapped: Head of a list with struct lock_class elements. | |
de4643a7 BVA |
313 | * @lock_chains_being_freed: Bitmap that indicates which lock_chains[] elements |
314 | * are about to be freed. | |
a0b0fd53 BVA |
315 | */ |
316 | struct pending_free { | |
317 | struct list_head zapped; | |
de4643a7 | 318 | DECLARE_BITMAP(lock_chains_being_freed, MAX_LOCKDEP_CHAINS); |
a0b0fd53 BVA |
319 | }; |
320 | ||
321 | /** | |
322 | * struct delayed_free - data structures used for delayed freeing | |
323 | * | |
324 | * A data structure for delayed freeing of data structures that may be | |
325 | * accessed by RCU readers at the time these were freed. | |
326 | * | |
327 | * @rcu_head: Used to schedule an RCU callback for freeing data structures. | |
328 | * @index: Index of @pf to which freed data structures are added. | |
329 | * @scheduled: Whether or not an RCU callback has been scheduled. | |
330 | * @pf: Array with information about data structures about to be freed. | |
331 | */ | |
332 | static struct delayed_free { | |
333 | struct rcu_head rcu_head; | |
334 | int index; | |
335 | int scheduled; | |
336 | struct pending_free pf[2]; | |
337 | } delayed_free; | |
fbb9ce95 IM |
338 | |
339 | /* | |
340 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
341 | */ | |
342 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
343 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 344 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
345 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
346 | ||
a63f38cc | 347 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
fbb9ce95 | 348 | |
fbb9ce95 IM |
349 | /* |
350 | * We put the lock dependency chains into a hash-table as well, to cache | |
351 | * their existence: | |
352 | */ | |
353 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
354 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 355 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
356 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
357 | ||
a63f38cc | 358 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
fbb9ce95 IM |
359 | |
360 | /* | |
361 | * The hash key of the lock dependency chains is a hash itself too: | |
362 | * it's a hash of all locks taken up to that lock, including that lock. | |
363 | * It's a 64-bit hash, because it's important for the keys to be | |
364 | * unique. | |
365 | */ | |
dfaaf3fa PZ |
366 | static inline u64 iterate_chain_key(u64 key, u32 idx) |
367 | { | |
368 | u32 k0 = key, k1 = key >> 32; | |
369 | ||
370 | __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ | |
371 | ||
372 | return k0 | (u64)k1 << 32; | |
373 | } | |
fbb9ce95 | 374 | |
e196e479 YD |
375 | void lockdep_init_task(struct task_struct *task) |
376 | { | |
377 | task->lockdep_depth = 0; /* no locks held yet */ | |
f6ec8829 | 378 | task->curr_chain_key = INITIAL_CHAIN_KEY; |
e196e479 YD |
379 | task->lockdep_recursion = 0; |
380 | } | |
381 | ||
1d09daa5 | 382 | void lockdep_off(void) |
fbb9ce95 IM |
383 | { |
384 | current->lockdep_recursion++; | |
385 | } | |
fbb9ce95 IM |
386 | EXPORT_SYMBOL(lockdep_off); |
387 | ||
1d09daa5 | 388 | void lockdep_on(void) |
fbb9ce95 IM |
389 | { |
390 | current->lockdep_recursion--; | |
391 | } | |
fbb9ce95 IM |
392 | EXPORT_SYMBOL(lockdep_on); |
393 | ||
cdc84d79 BVA |
394 | void lockdep_set_selftest_task(struct task_struct *task) |
395 | { | |
396 | lockdep_selftest_task_struct = task; | |
397 | } | |
398 | ||
fbb9ce95 IM |
399 | /* |
400 | * Debugging switches: | |
401 | */ | |
402 | ||
403 | #define VERBOSE 0 | |
33e94e96 | 404 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
405 | |
406 | #if VERBOSE | |
407 | # define HARDIRQ_VERBOSE 1 | |
408 | # define SOFTIRQ_VERBOSE 1 | |
409 | #else | |
410 | # define HARDIRQ_VERBOSE 0 | |
411 | # define SOFTIRQ_VERBOSE 0 | |
412 | #endif | |
413 | ||
d92a8cfc | 414 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE |
fbb9ce95 IM |
415 | /* |
416 | * Quick filtering for interesting events: | |
417 | */ | |
418 | static int class_filter(struct lock_class *class) | |
419 | { | |
f9829cce AK |
420 | #if 0 |
421 | /* Example */ | |
fbb9ce95 | 422 | if (class->name_version == 1 && |
f9829cce | 423 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
424 | return 1; |
425 | if (class->name_version == 1 && | |
f9829cce | 426 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 427 | return 1; |
f9829cce | 428 | #endif |
a6640897 IM |
429 | /* Filter everything else. 1 would be to allow everything else */ |
430 | return 0; | |
fbb9ce95 IM |
431 | } |
432 | #endif | |
433 | ||
434 | static int verbose(struct lock_class *class) | |
435 | { | |
436 | #if VERBOSE | |
437 | return class_filter(class); | |
438 | #endif | |
439 | return 0; | |
440 | } | |
441 | ||
2c522836 DJ |
442 | static void print_lockdep_off(const char *bug_msg) |
443 | { | |
444 | printk(KERN_DEBUG "%s\n", bug_msg); | |
445 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 446 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 447 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 448 | #endif |
2c522836 DJ |
449 | } |
450 | ||
886532ae AB |
451 | unsigned long nr_stack_trace_entries; |
452 | ||
30a35f79 | 453 | #ifdef CONFIG_PROVE_LOCKING |
12593b74 BVA |
454 | /** |
455 | * struct lock_trace - single stack backtrace | |
456 | * @hash_entry: Entry in a stack_trace_hash[] list. | |
457 | * @hash: jhash() of @entries. | |
458 | * @nr_entries: Number of entries in @entries. | |
459 | * @entries: Actual stack backtrace. | |
460 | */ | |
461 | struct lock_trace { | |
462 | struct hlist_node hash_entry; | |
463 | u32 hash; | |
464 | u32 nr_entries; | |
465 | unsigned long entries[0] __aligned(sizeof(unsigned long)); | |
466 | }; | |
467 | #define LOCK_TRACE_SIZE_IN_LONGS \ | |
468 | (sizeof(struct lock_trace) / sizeof(unsigned long)) | |
886532ae | 469 | /* |
12593b74 | 470 | * Stack-trace: sequence of lock_trace structures. Protected by the graph_lock. |
886532ae AB |
471 | */ |
472 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
12593b74 BVA |
473 | static struct hlist_head stack_trace_hash[STACK_TRACE_HASH_SIZE]; |
474 | ||
475 | static bool traces_identical(struct lock_trace *t1, struct lock_trace *t2) | |
476 | { | |
477 | return t1->hash == t2->hash && t1->nr_entries == t2->nr_entries && | |
478 | memcmp(t1->entries, t2->entries, | |
479 | t1->nr_entries * sizeof(t1->entries[0])) == 0; | |
480 | } | |
886532ae | 481 | |
12593b74 | 482 | static struct lock_trace *save_trace(void) |
fbb9ce95 | 483 | { |
12593b74 BVA |
484 | struct lock_trace *trace, *t2; |
485 | struct hlist_head *hash_head; | |
486 | u32 hash; | |
4f2803b7 | 487 | int max_entries; |
fbb9ce95 | 488 | |
12593b74 BVA |
489 | BUILD_BUG_ON_NOT_POWER_OF_2(STACK_TRACE_HASH_SIZE); |
490 | BUILD_BUG_ON(LOCK_TRACE_SIZE_IN_LONGS >= MAX_STACK_TRACE_ENTRIES); | |
491 | ||
492 | trace = (struct lock_trace *)(stack_trace + nr_stack_trace_entries); | |
493 | max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries - | |
494 | LOCK_TRACE_SIZE_IN_LONGS; | |
fbb9ce95 | 495 | |
4f2803b7 | 496 | if (max_entries <= 0) { |
74c383f1 | 497 | if (!debug_locks_off_graph_unlock()) |
12593b74 | 498 | return NULL; |
74c383f1 | 499 | |
2c522836 | 500 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
501 | dump_stack(); |
502 | ||
12593b74 | 503 | return NULL; |
fbb9ce95 | 504 | } |
4f2803b7 | 505 | trace->nr_entries = stack_trace_save(trace->entries, max_entries, 3); |
fbb9ce95 | 506 | |
12593b74 BVA |
507 | hash = jhash(trace->entries, trace->nr_entries * |
508 | sizeof(trace->entries[0]), 0); | |
509 | trace->hash = hash; | |
510 | hash_head = stack_trace_hash + (hash & (STACK_TRACE_HASH_SIZE - 1)); | |
511 | hlist_for_each_entry(t2, hash_head, hash_entry) { | |
512 | if (traces_identical(trace, t2)) | |
513 | return t2; | |
514 | } | |
515 | nr_stack_trace_entries += LOCK_TRACE_SIZE_IN_LONGS + trace->nr_entries; | |
516 | hlist_add_head(&trace->hash_entry, hash_head); | |
517 | ||
518 | return trace; | |
fbb9ce95 | 519 | } |
8c779229 BVA |
520 | |
521 | /* Return the number of stack traces in the stack_trace[] array. */ | |
522 | u64 lockdep_stack_trace_count(void) | |
523 | { | |
524 | struct lock_trace *trace; | |
525 | u64 c = 0; | |
526 | int i; | |
527 | ||
528 | for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++) { | |
529 | hlist_for_each_entry(trace, &stack_trace_hash[i], hash_entry) { | |
530 | c++; | |
531 | } | |
532 | } | |
533 | ||
534 | return c; | |
535 | } | |
536 | ||
537 | /* Return the number of stack hash chains that have at least one stack trace. */ | |
538 | u64 lockdep_stack_hash_count(void) | |
539 | { | |
540 | u64 c = 0; | |
541 | int i; | |
542 | ||
543 | for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++) | |
544 | if (!hlist_empty(&stack_trace_hash[i])) | |
545 | c++; | |
546 | ||
547 | return c; | |
fbb9ce95 | 548 | } |
886532ae | 549 | #endif |
fbb9ce95 IM |
550 | |
551 | unsigned int nr_hardirq_chains; | |
552 | unsigned int nr_softirq_chains; | |
553 | unsigned int nr_process_chains; | |
554 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
555 | |
556 | #ifdef CONFIG_DEBUG_LOCKDEP | |
fbb9ce95 IM |
557 | /* |
558 | * Various lockdep statistics: | |
559 | */ | |
bd6d29c2 | 560 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
561 | #endif |
562 | ||
30a35f79 | 563 | #ifdef CONFIG_PROVE_LOCKING |
fbb9ce95 IM |
564 | /* |
565 | * Locking printouts: | |
566 | */ | |
567 | ||
fabe9c42 | 568 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
569 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
570 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
571 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
572 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 573 | |
fbb9ce95 IM |
574 | static const char *usage_str[] = |
575 | { | |
fabe9c42 PZ |
576 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
577 | #include "lockdep_states.h" | |
578 | #undef LOCKDEP_STATE | |
579 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 | 580 | }; |
886532ae | 581 | #endif |
fbb9ce95 | 582 | |
364f6afc | 583 | const char *__get_key_name(const struct lockdep_subclass_key *key, char *str) |
fbb9ce95 | 584 | { |
ffb45122 | 585 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
586 | } |
587 | ||
3ff176ca | 588 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 589 | { |
3ff176ca PZ |
590 | return 1UL << bit; |
591 | } | |
fbb9ce95 | 592 | |
3ff176ca PZ |
593 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
594 | { | |
c52478f4 YD |
595 | /* |
596 | * The usage character defaults to '.' (i.e., irqs disabled and not in | |
597 | * irq context), which is the safest usage category. | |
598 | */ | |
3ff176ca PZ |
599 | char c = '.'; |
600 | ||
c52478f4 YD |
601 | /* |
602 | * The order of the following usage checks matters, which will | |
603 | * result in the outcome character as follows: | |
604 | * | |
605 | * - '+': irq is enabled and not in irq context | |
606 | * - '-': in irq context and irq is disabled | |
607 | * - '?': in irq context and irq is enabled | |
608 | */ | |
609 | if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) { | |
3ff176ca | 610 | c = '+'; |
c52478f4 | 611 | if (class->usage_mask & lock_flag(bit)) |
3ff176ca | 612 | c = '?'; |
c52478f4 YD |
613 | } else if (class->usage_mask & lock_flag(bit)) |
614 | c = '-'; | |
fbb9ce95 | 615 | |
3ff176ca PZ |
616 | return c; |
617 | } | |
cf40bd16 | 618 | |
f510b233 | 619 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 620 | { |
f510b233 | 621 | int i = 0; |
cf40bd16 | 622 | |
f510b233 PZ |
623 | #define LOCKDEP_STATE(__STATE) \ |
624 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
625 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
626 | #include "lockdep_states.h" | |
627 | #undef LOCKDEP_STATE | |
628 | ||
629 | usage[i] = '\0'; | |
fbb9ce95 IM |
630 | } |
631 | ||
e5e78d08 | 632 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
633 | { |
634 | char str[KSYM_NAME_LEN]; | |
635 | const char *name; | |
636 | ||
fbb9ce95 IM |
637 | name = class->name; |
638 | if (!name) { | |
639 | name = __get_key_name(class->key, str); | |
f943fe0f | 640 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 641 | } else { |
f943fe0f | 642 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 643 | if (class->name_version > 1) |
f943fe0f | 644 | printk(KERN_CONT "#%d", class->name_version); |
fbb9ce95 | 645 | if (class->subclass) |
f943fe0f | 646 | printk(KERN_CONT "/%d", class->subclass); |
fbb9ce95 | 647 | } |
e5e78d08 SR |
648 | } |
649 | ||
650 | static void print_lock_name(struct lock_class *class) | |
651 | { | |
652 | char usage[LOCK_USAGE_CHARS]; | |
653 | ||
654 | get_usage_chars(class, usage); | |
655 | ||
f943fe0f | 656 | printk(KERN_CONT " ("); |
e5e78d08 | 657 | __print_lock_name(class); |
f943fe0f | 658 | printk(KERN_CONT "){%s}", usage); |
fbb9ce95 IM |
659 | } |
660 | ||
661 | static void print_lockdep_cache(struct lockdep_map *lock) | |
662 | { | |
663 | const char *name; | |
9281acea | 664 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
665 | |
666 | name = lock->name; | |
667 | if (!name) | |
668 | name = __get_key_name(lock->key->subkeys, str); | |
669 | ||
f943fe0f | 670 | printk(KERN_CONT "%s", name); |
fbb9ce95 IM |
671 | } |
672 | ||
673 | static void print_lock(struct held_lock *hlock) | |
674 | { | |
d7bc3197 PZ |
675 | /* |
676 | * We can be called locklessly through debug_show_all_locks() so be | |
677 | * extra careful, the hlock might have been released and cleared. | |
01bb6f0a YD |
678 | * |
679 | * If this indeed happens, lets pretend it does not hurt to continue | |
680 | * to print the lock unless the hlock class_idx does not point to a | |
681 | * registered class. The rationale here is: since we don't attempt | |
682 | * to distinguish whether we are in this situation, if it just | |
683 | * happened we can't count on class_idx to tell either. | |
d7bc3197 | 684 | */ |
01bb6f0a | 685 | struct lock_class *lock = hlock_class(hlock); |
d7bc3197 | 686 | |
01bb6f0a | 687 | if (!lock) { |
f943fe0f | 688 | printk(KERN_CONT "<RELEASED>\n"); |
d7bc3197 PZ |
689 | return; |
690 | } | |
691 | ||
519248f3 | 692 | printk(KERN_CONT "%px", hlock->instance); |
01bb6f0a | 693 | print_lock_name(lock); |
b3c39758 | 694 | printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip); |
fbb9ce95 IM |
695 | } |
696 | ||
8cc05c71 | 697 | static void lockdep_print_held_locks(struct task_struct *p) |
fbb9ce95 | 698 | { |
8cc05c71 | 699 | int i, depth = READ_ONCE(p->lockdep_depth); |
fbb9ce95 | 700 | |
8cc05c71 TH |
701 | if (!depth) |
702 | printk("no locks held by %s/%d.\n", p->comm, task_pid_nr(p)); | |
703 | else | |
704 | printk("%d lock%s held by %s/%d:\n", depth, | |
705 | depth > 1 ? "s" : "", p->comm, task_pid_nr(p)); | |
706 | /* | |
707 | * It's not reliable to print a task's held locks if it's not sleeping | |
708 | * and it's not the current task. | |
709 | */ | |
710 | if (p->state == TASK_RUNNING && p != current) | |
fbb9ce95 | 711 | return; |
fbb9ce95 IM |
712 | for (i = 0; i < depth; i++) { |
713 | printk(" #%d: ", i); | |
8cc05c71 | 714 | print_lock(p->held_locks + i); |
fbb9ce95 IM |
715 | } |
716 | } | |
fbb9ce95 | 717 | |
fbdc4b9a | 718 | static void print_kernel_ident(void) |
8e18257d | 719 | { |
fbdc4b9a | 720 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 721 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
722 | init_utsname()->version, |
723 | print_tainted()); | |
8e18257d PZ |
724 | } |
725 | ||
726 | static int very_verbose(struct lock_class *class) | |
727 | { | |
728 | #if VERY_VERBOSE | |
729 | return class_filter(class); | |
730 | #endif | |
731 | return 0; | |
732 | } | |
733 | ||
fbb9ce95 | 734 | /* |
8e18257d | 735 | * Is this the address of a static object: |
fbb9ce95 | 736 | */ |
8dce7a9a | 737 | #ifdef __KERNEL__ |
108c1485 | 738 | static int static_obj(const void *obj) |
fbb9ce95 | 739 | { |
8e18257d PZ |
740 | unsigned long start = (unsigned long) &_stext, |
741 | end = (unsigned long) &_end, | |
742 | addr = (unsigned long) obj; | |
8e18257d | 743 | |
7a5da02d GS |
744 | if (arch_is_kernel_initmem_freed(addr)) |
745 | return 0; | |
746 | ||
fbb9ce95 | 747 | /* |
8e18257d | 748 | * static variable? |
fbb9ce95 | 749 | */ |
8e18257d PZ |
750 | if ((addr >= start) && (addr < end)) |
751 | return 1; | |
fbb9ce95 | 752 | |
2a9ad18d MF |
753 | if (arch_is_kernel_data(addr)) |
754 | return 1; | |
755 | ||
fbb9ce95 | 756 | /* |
10fad5e4 | 757 | * in-kernel percpu var? |
fbb9ce95 | 758 | */ |
10fad5e4 TH |
759 | if (is_kernel_percpu_address(addr)) |
760 | return 1; | |
fbb9ce95 | 761 | |
8e18257d | 762 | /* |
10fad5e4 | 763 | * module static or percpu var? |
8e18257d | 764 | */ |
10fad5e4 | 765 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 766 | } |
8dce7a9a | 767 | #endif |
99de055a | 768 | |
fbb9ce95 | 769 | /* |
8e18257d | 770 | * To make lock name printouts unique, we calculate a unique |
fe27b0de BVA |
771 | * class->name_version generation counter. The caller must hold the graph |
772 | * lock. | |
fbb9ce95 | 773 | */ |
8e18257d | 774 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 775 | { |
8e18257d PZ |
776 | struct lock_class *class; |
777 | int count = 0; | |
fbb9ce95 | 778 | |
8e18257d | 779 | if (!new_class->name) |
fbb9ce95 IM |
780 | return 0; |
781 | ||
fe27b0de | 782 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
783 | if (new_class->key - new_class->subclass == class->key) |
784 | return class->name_version; | |
785 | if (class->name && !strcmp(class->name, new_class->name)) | |
786 | count = max(count, class->name_version); | |
787 | } | |
fbb9ce95 | 788 | |
8e18257d | 789 | return count + 1; |
fbb9ce95 IM |
790 | } |
791 | ||
8e18257d | 792 | static inline struct lock_class * |
08f36ff6 | 793 | look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass) |
fbb9ce95 | 794 | { |
8e18257d | 795 | struct lockdep_subclass_key *key; |
a63f38cc | 796 | struct hlist_head *hash_head; |
8e18257d | 797 | struct lock_class *class; |
fbb9ce95 | 798 | |
4ba053c0 HM |
799 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
800 | debug_locks_off(); | |
801 | printk(KERN_ERR | |
802 | "BUG: looking up invalid subclass: %u\n", subclass); | |
803 | printk(KERN_ERR | |
804 | "turning off the locking correctness validator.\n"); | |
805 | dump_stack(); | |
806 | return NULL; | |
807 | } | |
808 | ||
8e18257d | 809 | /* |
64f29d1b MW |
810 | * If it is not initialised then it has never been locked, |
811 | * so it won't be present in the hash table. | |
8e18257d | 812 | */ |
64f29d1b MW |
813 | if (unlikely(!lock->key)) |
814 | return NULL; | |
fbb9ce95 | 815 | |
8e18257d PZ |
816 | /* |
817 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
818 | * lock_class_key variable is passed in through the mutex_init() | |
819 | * (or spin_lock_init()) call - which acts as the key. For static | |
820 | * locks we use the lock object itself as the key. | |
821 | */ | |
4b32d0a4 PZ |
822 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
823 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 824 | |
8e18257d | 825 | key = lock->key->subkeys + subclass; |
ca268c69 | 826 | |
8e18257d | 827 | hash_head = classhashentry(key); |
74c383f1 | 828 | |
8e18257d | 829 | /* |
35a9393c | 830 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 831 | */ |
35a9393c PZ |
832 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
833 | return NULL; | |
834 | ||
a63f38cc | 835 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
4b32d0a4 | 836 | if (class->key == key) { |
0119fee4 PZ |
837 | /* |
838 | * Huh! same key, different name? Did someone trample | |
839 | * on some memory? We're most confused. | |
840 | */ | |
97831546 SAS |
841 | WARN_ON_ONCE(class->name != lock->name && |
842 | lock->key != &__lockdep_no_validate__); | |
8e18257d | 843 | return class; |
4b32d0a4 PZ |
844 | } |
845 | } | |
fbb9ce95 | 846 | |
64f29d1b MW |
847 | return NULL; |
848 | } | |
849 | ||
850 | /* | |
851 | * Static locks do not have their class-keys yet - for them the key is | |
852 | * the lock object itself. If the lock is in the per cpu area, the | |
853 | * canonical address of the lock (per cpu offset removed) is used. | |
854 | */ | |
855 | static bool assign_lock_key(struct lockdep_map *lock) | |
856 | { | |
857 | unsigned long can_addr, addr = (unsigned long)lock; | |
858 | ||
4bf50862 BVA |
859 | #ifdef __KERNEL__ |
860 | /* | |
861 | * lockdep_free_key_range() assumes that struct lock_class_key | |
862 | * objects do not overlap. Since we use the address of lock | |
863 | * objects as class key for static objects, check whether the | |
864 | * size of lock_class_key objects does not exceed the size of | |
865 | * the smallest lock object. | |
866 | */ | |
867 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(raw_spinlock_t)); | |
868 | #endif | |
869 | ||
64f29d1b MW |
870 | if (__is_kernel_percpu_address(addr, &can_addr)) |
871 | lock->key = (void *)can_addr; | |
872 | else if (__is_module_percpu_address(addr, &can_addr)) | |
873 | lock->key = (void *)can_addr; | |
874 | else if (static_obj(lock)) | |
875 | lock->key = (void *)lock; | |
876 | else { | |
877 | /* Debug-check: all keys must be persistent! */ | |
878 | debug_locks_off(); | |
879 | pr_err("INFO: trying to register non-static key.\n"); | |
880 | pr_err("the code is fine but needs lockdep annotation.\n"); | |
881 | pr_err("turning off the locking correctness validator.\n"); | |
882 | dump_stack(); | |
883 | return false; | |
884 | } | |
885 | ||
886 | return true; | |
fbb9ce95 IM |
887 | } |
888 | ||
72dcd505 PZ |
889 | #ifdef CONFIG_DEBUG_LOCKDEP |
890 | ||
b526b2e3 BVA |
891 | /* Check whether element @e occurs in list @h */ |
892 | static bool in_list(struct list_head *e, struct list_head *h) | |
893 | { | |
894 | struct list_head *f; | |
895 | ||
896 | list_for_each(f, h) { | |
897 | if (e == f) | |
898 | return true; | |
899 | } | |
900 | ||
901 | return false; | |
902 | } | |
903 | ||
904 | /* | |
905 | * Check whether entry @e occurs in any of the locks_after or locks_before | |
906 | * lists. | |
907 | */ | |
908 | static bool in_any_class_list(struct list_head *e) | |
909 | { | |
910 | struct lock_class *class; | |
911 | int i; | |
912 | ||
913 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { | |
914 | class = &lock_classes[i]; | |
915 | if (in_list(e, &class->locks_after) || | |
916 | in_list(e, &class->locks_before)) | |
917 | return true; | |
918 | } | |
919 | return false; | |
920 | } | |
921 | ||
922 | static bool class_lock_list_valid(struct lock_class *c, struct list_head *h) | |
923 | { | |
924 | struct lock_list *e; | |
925 | ||
926 | list_for_each_entry(e, h, entry) { | |
927 | if (e->links_to != c) { | |
928 | printk(KERN_INFO "class %s: mismatch for lock entry %ld; class %s <> %s", | |
929 | c->name ? : "(?)", | |
930 | (unsigned long)(e - list_entries), | |
931 | e->links_to && e->links_to->name ? | |
932 | e->links_to->name : "(?)", | |
933 | e->class && e->class->name ? e->class->name : | |
934 | "(?)"); | |
935 | return false; | |
936 | } | |
937 | } | |
938 | return true; | |
939 | } | |
940 | ||
3fe7522f AB |
941 | #ifdef CONFIG_PROVE_LOCKING |
942 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; | |
943 | #endif | |
b526b2e3 BVA |
944 | |
945 | static bool check_lock_chain_key(struct lock_chain *chain) | |
946 | { | |
947 | #ifdef CONFIG_PROVE_LOCKING | |
f6ec8829 | 948 | u64 chain_key = INITIAL_CHAIN_KEY; |
b526b2e3 BVA |
949 | int i; |
950 | ||
951 | for (i = chain->base; i < chain->base + chain->depth; i++) | |
01bb6f0a | 952 | chain_key = iterate_chain_key(chain_key, chain_hlocks[i]); |
b526b2e3 BVA |
953 | /* |
954 | * The 'unsigned long long' casts avoid that a compiler warning | |
955 | * is reported when building tools/lib/lockdep. | |
956 | */ | |
72dcd505 | 957 | if (chain->chain_key != chain_key) { |
b526b2e3 BVA |
958 | printk(KERN_INFO "chain %lld: key %#llx <> %#llx\n", |
959 | (unsigned long long)(chain - lock_chains), | |
960 | (unsigned long long)chain->chain_key, | |
961 | (unsigned long long)chain_key); | |
72dcd505 PZ |
962 | return false; |
963 | } | |
b526b2e3 | 964 | #endif |
72dcd505 | 965 | return true; |
b526b2e3 BVA |
966 | } |
967 | ||
968 | static bool in_any_zapped_class_list(struct lock_class *class) | |
969 | { | |
970 | struct pending_free *pf; | |
971 | int i; | |
972 | ||
72dcd505 | 973 | for (i = 0, pf = delayed_free.pf; i < ARRAY_SIZE(delayed_free.pf); i++, pf++) { |
b526b2e3 BVA |
974 | if (in_list(&class->lock_entry, &pf->zapped)) |
975 | return true; | |
72dcd505 | 976 | } |
b526b2e3 BVA |
977 | |
978 | return false; | |
979 | } | |
980 | ||
72dcd505 | 981 | static bool __check_data_structures(void) |
b526b2e3 BVA |
982 | { |
983 | struct lock_class *class; | |
984 | struct lock_chain *chain; | |
985 | struct hlist_head *head; | |
986 | struct lock_list *e; | |
987 | int i; | |
988 | ||
989 | /* Check whether all classes occur in a lock list. */ | |
990 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { | |
991 | class = &lock_classes[i]; | |
992 | if (!in_list(&class->lock_entry, &all_lock_classes) && | |
993 | !in_list(&class->lock_entry, &free_lock_classes) && | |
994 | !in_any_zapped_class_list(class)) { | |
995 | printk(KERN_INFO "class %px/%s is not in any class list\n", | |
996 | class, class->name ? : "(?)"); | |
997 | return false; | |
b526b2e3 BVA |
998 | } |
999 | } | |
1000 | ||
1001 | /* Check whether all classes have valid lock lists. */ | |
1002 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { | |
1003 | class = &lock_classes[i]; | |
1004 | if (!class_lock_list_valid(class, &class->locks_before)) | |
1005 | return false; | |
1006 | if (!class_lock_list_valid(class, &class->locks_after)) | |
1007 | return false; | |
1008 | } | |
1009 | ||
1010 | /* Check the chain_key of all lock chains. */ | |
1011 | for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) { | |
1012 | head = chainhash_table + i; | |
1013 | hlist_for_each_entry_rcu(chain, head, entry) { | |
1014 | if (!check_lock_chain_key(chain)) | |
1015 | return false; | |
1016 | } | |
1017 | } | |
1018 | ||
1019 | /* | |
1020 | * Check whether all list entries that are in use occur in a class | |
1021 | * lock list. | |
1022 | */ | |
1023 | for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) { | |
1024 | e = list_entries + i; | |
1025 | if (!in_any_class_list(&e->entry)) { | |
1026 | printk(KERN_INFO "list entry %d is not in any class list; class %s <> %s\n", | |
1027 | (unsigned int)(e - list_entries), | |
1028 | e->class->name ? : "(?)", | |
1029 | e->links_to->name ? : "(?)"); | |
1030 | return false; | |
1031 | } | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * Check whether all list entries that are not in use do not occur in | |
1036 | * a class lock list. | |
1037 | */ | |
1038 | for_each_clear_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) { | |
1039 | e = list_entries + i; | |
1040 | if (in_any_class_list(&e->entry)) { | |
1041 | printk(KERN_INFO "list entry %d occurs in a class list; class %s <> %s\n", | |
1042 | (unsigned int)(e - list_entries), | |
1043 | e->class && e->class->name ? e->class->name : | |
1044 | "(?)", | |
1045 | e->links_to && e->links_to->name ? | |
1046 | e->links_to->name : "(?)"); | |
1047 | return false; | |
1048 | } | |
1049 | } | |
1050 | ||
1051 | return true; | |
1052 | } | |
1053 | ||
72dcd505 PZ |
1054 | int check_consistency = 0; |
1055 | module_param(check_consistency, int, 0644); | |
1056 | ||
1057 | static void check_data_structures(void) | |
1058 | { | |
1059 | static bool once = false; | |
1060 | ||
1061 | if (check_consistency && !once) { | |
1062 | if (!__check_data_structures()) { | |
1063 | once = true; | |
1064 | WARN_ON(once); | |
1065 | } | |
1066 | } | |
1067 | } | |
1068 | ||
1069 | #else /* CONFIG_DEBUG_LOCKDEP */ | |
1070 | ||
1071 | static inline void check_data_structures(void) { } | |
1072 | ||
1073 | #endif /* CONFIG_DEBUG_LOCKDEP */ | |
1074 | ||
feb0a386 | 1075 | /* |
a0b0fd53 BVA |
1076 | * Initialize the lock_classes[] array elements, the free_lock_classes list |
1077 | * and also the delayed_free structure. | |
feb0a386 BVA |
1078 | */ |
1079 | static void init_data_structures_once(void) | |
1080 | { | |
0126574f | 1081 | static bool ds_initialized, rcu_head_initialized; |
feb0a386 BVA |
1082 | int i; |
1083 | ||
0126574f | 1084 | if (likely(rcu_head_initialized)) |
feb0a386 BVA |
1085 | return; |
1086 | ||
0126574f BVA |
1087 | if (system_state >= SYSTEM_SCHEDULING) { |
1088 | init_rcu_head(&delayed_free.rcu_head); | |
1089 | rcu_head_initialized = true; | |
1090 | } | |
1091 | ||
1092 | if (ds_initialized) | |
1093 | return; | |
1094 | ||
1095 | ds_initialized = true; | |
feb0a386 | 1096 | |
a0b0fd53 BVA |
1097 | INIT_LIST_HEAD(&delayed_free.pf[0].zapped); |
1098 | INIT_LIST_HEAD(&delayed_free.pf[1].zapped); | |
1099 | ||
feb0a386 | 1100 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { |
a0b0fd53 | 1101 | list_add_tail(&lock_classes[i].lock_entry, &free_lock_classes); |
feb0a386 BVA |
1102 | INIT_LIST_HEAD(&lock_classes[i].locks_after); |
1103 | INIT_LIST_HEAD(&lock_classes[i].locks_before); | |
1104 | } | |
1105 | } | |
1106 | ||
108c1485 BVA |
1107 | static inline struct hlist_head *keyhashentry(const struct lock_class_key *key) |
1108 | { | |
1109 | unsigned long hash = hash_long((uintptr_t)key, KEYHASH_BITS); | |
1110 | ||
1111 | return lock_keys_hash + hash; | |
1112 | } | |
1113 | ||
1114 | /* Register a dynamically allocated key. */ | |
1115 | void lockdep_register_key(struct lock_class_key *key) | |
1116 | { | |
1117 | struct hlist_head *hash_head; | |
1118 | struct lock_class_key *k; | |
1119 | unsigned long flags; | |
1120 | ||
1121 | if (WARN_ON_ONCE(static_obj(key))) | |
1122 | return; | |
1123 | hash_head = keyhashentry(key); | |
1124 | ||
1125 | raw_local_irq_save(flags); | |
1126 | if (!graph_lock()) | |
1127 | goto restore_irqs; | |
1128 | hlist_for_each_entry_rcu(k, hash_head, hash_entry) { | |
1129 | if (WARN_ON_ONCE(k == key)) | |
1130 | goto out_unlock; | |
1131 | } | |
1132 | hlist_add_head_rcu(&key->hash_entry, hash_head); | |
1133 | out_unlock: | |
1134 | graph_unlock(); | |
1135 | restore_irqs: | |
1136 | raw_local_irq_restore(flags); | |
1137 | } | |
1138 | EXPORT_SYMBOL_GPL(lockdep_register_key); | |
1139 | ||
1140 | /* Check whether a key has been registered as a dynamic key. */ | |
1141 | static bool is_dynamic_key(const struct lock_class_key *key) | |
1142 | { | |
1143 | struct hlist_head *hash_head; | |
1144 | struct lock_class_key *k; | |
1145 | bool found = false; | |
1146 | ||
1147 | if (WARN_ON_ONCE(static_obj(key))) | |
1148 | return false; | |
1149 | ||
1150 | /* | |
1151 | * If lock debugging is disabled lock_keys_hash[] may contain | |
1152 | * pointers to memory that has already been freed. Avoid triggering | |
1153 | * a use-after-free in that case by returning early. | |
1154 | */ | |
1155 | if (!debug_locks) | |
1156 | return true; | |
1157 | ||
1158 | hash_head = keyhashentry(key); | |
1159 | ||
1160 | rcu_read_lock(); | |
1161 | hlist_for_each_entry_rcu(k, hash_head, hash_entry) { | |
1162 | if (k == key) { | |
1163 | found = true; | |
1164 | break; | |
1165 | } | |
1166 | } | |
1167 | rcu_read_unlock(); | |
1168 | ||
1169 | return found; | |
1170 | } | |
1171 | ||
fbb9ce95 | 1172 | /* |
8e18257d PZ |
1173 | * Register a lock's class in the hash-table, if the class is not present |
1174 | * yet. Otherwise we look it up. We cache the result in the lock object | |
1175 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 1176 | */ |
c003ed92 | 1177 | static struct lock_class * |
8e18257d | 1178 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
fbb9ce95 | 1179 | { |
8e18257d | 1180 | struct lockdep_subclass_key *key; |
a63f38cc | 1181 | struct hlist_head *hash_head; |
8e18257d | 1182 | struct lock_class *class; |
35a9393c PZ |
1183 | |
1184 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
1185 | |
1186 | class = look_up_lock_class(lock, subclass); | |
64f29d1b | 1187 | if (likely(class)) |
87cdee71 | 1188 | goto out_set_class_cache; |
8e18257d | 1189 | |
64f29d1b MW |
1190 | if (!lock->key) { |
1191 | if (!assign_lock_key(lock)) | |
1192 | return NULL; | |
108c1485 | 1193 | } else if (!static_obj(lock->key) && !is_dynamic_key(lock->key)) { |
8e18257d PZ |
1194 | return NULL; |
1195 | } | |
1196 | ||
1197 | key = lock->key->subkeys + subclass; | |
1198 | hash_head = classhashentry(key); | |
1199 | ||
8e18257d | 1200 | if (!graph_lock()) { |
8e18257d PZ |
1201 | return NULL; |
1202 | } | |
1203 | /* | |
1204 | * We have to do the hash-walk again, to avoid races | |
1205 | * with another CPU: | |
1206 | */ | |
a63f38cc | 1207 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
1208 | if (class->key == key) |
1209 | goto out_unlock_set; | |
35a9393c PZ |
1210 | } |
1211 | ||
feb0a386 BVA |
1212 | init_data_structures_once(); |
1213 | ||
a0b0fd53 BVA |
1214 | /* Allocate a new lock class and add it to the hash. */ |
1215 | class = list_first_entry_or_null(&free_lock_classes, typeof(*class), | |
1216 | lock_entry); | |
1217 | if (!class) { | |
8e18257d | 1218 | if (!debug_locks_off_graph_unlock()) { |
8e18257d PZ |
1219 | return NULL; |
1220 | } | |
8e18257d | 1221 | |
2c522836 | 1222 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 1223 | dump_stack(); |
8e18257d PZ |
1224 | return NULL; |
1225 | } | |
a0b0fd53 | 1226 | nr_lock_classes++; |
01bb6f0a | 1227 | __set_bit(class - lock_classes, lock_classes_in_use); |
bd6d29c2 | 1228 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
1229 | class->key = key; |
1230 | class->name = lock->name; | |
1231 | class->subclass = subclass; | |
feb0a386 BVA |
1232 | WARN_ON_ONCE(!list_empty(&class->locks_before)); |
1233 | WARN_ON_ONCE(!list_empty(&class->locks_after)); | |
8e18257d PZ |
1234 | class->name_version = count_matching_names(class); |
1235 | /* | |
1236 | * We use RCU's safe list-add method to make | |
1237 | * parallel walking of the hash-list safe: | |
1238 | */ | |
a63f38cc | 1239 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
1481197b | 1240 | /* |
a0b0fd53 BVA |
1241 | * Remove the class from the free list and add it to the global list |
1242 | * of classes. | |
1481197b | 1243 | */ |
a0b0fd53 | 1244 | list_move_tail(&class->lock_entry, &all_lock_classes); |
8e18257d PZ |
1245 | |
1246 | if (verbose(class)) { | |
1247 | graph_unlock(); | |
8e18257d | 1248 | |
04860d48 | 1249 | printk("\nnew class %px: %s", class->key, class->name); |
8e18257d | 1250 | if (class->name_version > 1) |
f943fe0f DV |
1251 | printk(KERN_CONT "#%d", class->name_version); |
1252 | printk(KERN_CONT "\n"); | |
8e18257d PZ |
1253 | dump_stack(); |
1254 | ||
8e18257d | 1255 | if (!graph_lock()) { |
8e18257d PZ |
1256 | return NULL; |
1257 | } | |
1258 | } | |
1259 | out_unlock_set: | |
1260 | graph_unlock(); | |
8e18257d | 1261 | |
87cdee71 | 1262 | out_set_class_cache: |
8e18257d | 1263 | if (!subclass || force) |
62016250 HM |
1264 | lock->class_cache[0] = class; |
1265 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
1266 | lock->class_cache[subclass] = class; | |
8e18257d | 1267 | |
0119fee4 PZ |
1268 | /* |
1269 | * Hash collision, did we smoke some? We found a class with a matching | |
1270 | * hash but the subclass -- which is hashed in -- didn't match. | |
1271 | */ | |
8e18257d PZ |
1272 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
1273 | return NULL; | |
1274 | ||
1275 | return class; | |
1276 | } | |
1277 | ||
1278 | #ifdef CONFIG_PROVE_LOCKING | |
1279 | /* | |
1280 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
1281 | * with NULL on failure) | |
1282 | */ | |
1283 | static struct lock_list *alloc_list_entry(void) | |
1284 | { | |
ace35a7a BVA |
1285 | int idx = find_first_zero_bit(list_entries_in_use, |
1286 | ARRAY_SIZE(list_entries)); | |
1287 | ||
1288 | if (idx >= ARRAY_SIZE(list_entries)) { | |
8e18257d PZ |
1289 | if (!debug_locks_off_graph_unlock()) |
1290 | return NULL; | |
1291 | ||
2c522836 | 1292 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 1293 | dump_stack(); |
8e18257d PZ |
1294 | return NULL; |
1295 | } | |
ace35a7a BVA |
1296 | nr_list_entries++; |
1297 | __set_bit(idx, list_entries_in_use); | |
1298 | return list_entries + idx; | |
8e18257d PZ |
1299 | } |
1300 | ||
1301 | /* | |
1302 | * Add a new dependency to the head of the list: | |
1303 | */ | |
86cffb80 BVA |
1304 | static int add_lock_to_list(struct lock_class *this, |
1305 | struct lock_class *links_to, struct list_head *head, | |
83f06168 | 1306 | unsigned long ip, int distance, |
12593b74 | 1307 | const struct lock_trace *trace) |
8e18257d PZ |
1308 | { |
1309 | struct lock_list *entry; | |
1310 | /* | |
1311 | * Lock not present yet - get a new dependency struct and | |
1312 | * add it to the list: | |
1313 | */ | |
1314 | entry = alloc_list_entry(); | |
1315 | if (!entry) | |
1316 | return 0; | |
1317 | ||
74870172 | 1318 | entry->class = this; |
86cffb80 | 1319 | entry->links_to = links_to; |
74870172 | 1320 | entry->distance = distance; |
12593b74 | 1321 | entry->trace = trace; |
8e18257d | 1322 | /* |
35a9393c PZ |
1323 | * Both allocation and removal are done under the graph lock; but |
1324 | * iteration is under RCU-sched; see look_up_lock_class() and | |
1325 | * lockdep_free_key_range(). | |
8e18257d PZ |
1326 | */ |
1327 | list_add_tail_rcu(&entry->entry, head); | |
1328 | ||
1329 | return 1; | |
1330 | } | |
1331 | ||
98c33edd PZ |
1332 | /* |
1333 | * For good efficiency of modular, we use power of 2 | |
1334 | */ | |
af012961 PZ |
1335 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
1336 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
1337 | ||
98c33edd | 1338 | /* |
aa480771 YD |
1339 | * The circular_queue and helpers are used to implement graph |
1340 | * breadth-first search (BFS) algorithm, by which we can determine | |
1341 | * whether there is a path from a lock to another. In deadlock checks, | |
1342 | * a path from the next lock to be acquired to a previous held lock | |
1343 | * indicates that adding the <prev> -> <next> lock dependency will | |
1344 | * produce a circle in the graph. Breadth-first search instead of | |
1345 | * depth-first search is used in order to find the shortest (circular) | |
1346 | * path. | |
98c33edd | 1347 | */ |
af012961 | 1348 | struct circular_queue { |
aa480771 | 1349 | struct lock_list *element[MAX_CIRCULAR_QUEUE_SIZE]; |
af012961 PZ |
1350 | unsigned int front, rear; |
1351 | }; | |
1352 | ||
1353 | static struct circular_queue lock_cq; | |
af012961 | 1354 | |
12f3dfd0 | 1355 | unsigned int max_bfs_queue_depth; |
af012961 | 1356 | |
e351b660 ML |
1357 | static unsigned int lockdep_dependency_gen_id; |
1358 | ||
af012961 PZ |
1359 | static inline void __cq_init(struct circular_queue *cq) |
1360 | { | |
1361 | cq->front = cq->rear = 0; | |
e351b660 | 1362 | lockdep_dependency_gen_id++; |
af012961 PZ |
1363 | } |
1364 | ||
1365 | static inline int __cq_empty(struct circular_queue *cq) | |
1366 | { | |
1367 | return (cq->front == cq->rear); | |
1368 | } | |
1369 | ||
1370 | static inline int __cq_full(struct circular_queue *cq) | |
1371 | { | |
1372 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
1373 | } | |
1374 | ||
aa480771 | 1375 | static inline int __cq_enqueue(struct circular_queue *cq, struct lock_list *elem) |
af012961 PZ |
1376 | { |
1377 | if (__cq_full(cq)) | |
1378 | return -1; | |
1379 | ||
1380 | cq->element[cq->rear] = elem; | |
1381 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
1382 | return 0; | |
1383 | } | |
1384 | ||
c1661325 YD |
1385 | /* |
1386 | * Dequeue an element from the circular_queue, return a lock_list if | |
1387 | * the queue is not empty, or NULL if otherwise. | |
1388 | */ | |
1389 | static inline struct lock_list * __cq_dequeue(struct circular_queue *cq) | |
af012961 | 1390 | { |
c1661325 YD |
1391 | struct lock_list * lock; |
1392 | ||
af012961 | 1393 | if (__cq_empty(cq)) |
c1661325 | 1394 | return NULL; |
af012961 | 1395 | |
c1661325 | 1396 | lock = cq->element[cq->front]; |
af012961 | 1397 | cq->front = (cq->front + 1) & CQ_MASK; |
c1661325 YD |
1398 | |
1399 | return lock; | |
af012961 PZ |
1400 | } |
1401 | ||
1402 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
1403 | { | |
1404 | return (cq->rear - cq->front) & CQ_MASK; | |
1405 | } | |
1406 | ||
1407 | static inline void mark_lock_accessed(struct lock_list *lock, | |
1408 | struct lock_list *parent) | |
1409 | { | |
1410 | unsigned long nr; | |
98c33edd | 1411 | |
af012961 | 1412 | nr = lock - list_entries; |
ace35a7a | 1413 | WARN_ON(nr >= ARRAY_SIZE(list_entries)); /* Out-of-bounds, input fail */ |
af012961 | 1414 | lock->parent = parent; |
e351b660 | 1415 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
1416 | } |
1417 | ||
1418 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
1419 | { | |
1420 | unsigned long nr; | |
98c33edd | 1421 | |
af012961 | 1422 | nr = lock - list_entries; |
ace35a7a | 1423 | WARN_ON(nr >= ARRAY_SIZE(list_entries)); /* Out-of-bounds, input fail */ |
e351b660 | 1424 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
1425 | } |
1426 | ||
1427 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
1428 | { | |
1429 | return child->parent; | |
1430 | } | |
1431 | ||
1432 | static inline int get_lock_depth(struct lock_list *child) | |
1433 | { | |
1434 | int depth = 0; | |
1435 | struct lock_list *parent; | |
1436 | ||
1437 | while ((parent = get_lock_parent(child))) { | |
1438 | child = parent; | |
1439 | depth++; | |
1440 | } | |
1441 | return depth; | |
1442 | } | |
1443 | ||
77a80692 YD |
1444 | /* |
1445 | * Return the forward or backward dependency list. | |
1446 | * | |
1447 | * @lock: the lock_list to get its class's dependency list | |
1448 | * @offset: the offset to struct lock_class to determine whether it is | |
1449 | * locks_after or locks_before | |
1450 | */ | |
1451 | static inline struct list_head *get_dep_list(struct lock_list *lock, int offset) | |
1452 | { | |
1453 | void *lock_class = lock->class; | |
1454 | ||
1455 | return lock_class + offset; | |
1456 | } | |
1457 | ||
154f185e YD |
1458 | /* |
1459 | * Forward- or backward-dependency search, used for both circular dependency | |
1460 | * checking and hardirq-unsafe/softirq-unsafe checking. | |
1461 | */ | |
9e2d551e | 1462 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
1463 | void *data, |
1464 | int (*match)(struct lock_list *entry, void *data), | |
1465 | struct lock_list **target_entry, | |
77a80692 | 1466 | int offset) |
c94aa5ca ML |
1467 | { |
1468 | struct lock_list *entry; | |
c1661325 | 1469 | struct lock_list *lock; |
d588e461 | 1470 | struct list_head *head; |
c94aa5ca ML |
1471 | struct circular_queue *cq = &lock_cq; |
1472 | int ret = 1; | |
1473 | ||
9e2d551e | 1474 | if (match(source_entry, data)) { |
c94aa5ca ML |
1475 | *target_entry = source_entry; |
1476 | ret = 0; | |
1477 | goto exit; | |
1478 | } | |
1479 | ||
77a80692 | 1480 | head = get_dep_list(source_entry, offset); |
d588e461 ML |
1481 | if (list_empty(head)) |
1482 | goto exit; | |
1483 | ||
1484 | __cq_init(cq); | |
aa480771 | 1485 | __cq_enqueue(cq, source_entry); |
c94aa5ca | 1486 | |
c1661325 | 1487 | while ((lock = __cq_dequeue(cq))) { |
c94aa5ca ML |
1488 | |
1489 | if (!lock->class) { | |
1490 | ret = -2; | |
1491 | goto exit; | |
1492 | } | |
1493 | ||
77a80692 | 1494 | head = get_dep_list(lock, offset); |
c94aa5ca | 1495 | |
35a9393c PZ |
1496 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1497 | ||
1498 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1499 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1500 | unsigned int cq_depth; |
c94aa5ca | 1501 | mark_lock_accessed(entry, lock); |
9e2d551e | 1502 | if (match(entry, data)) { |
c94aa5ca ML |
1503 | *target_entry = entry; |
1504 | ret = 0; | |
1505 | goto exit; | |
1506 | } | |
1507 | ||
aa480771 | 1508 | if (__cq_enqueue(cq, entry)) { |
c94aa5ca ML |
1509 | ret = -1; |
1510 | goto exit; | |
1511 | } | |
12f3dfd0 ML |
1512 | cq_depth = __cq_get_elem_count(cq); |
1513 | if (max_bfs_queue_depth < cq_depth) | |
1514 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1515 | } |
1516 | } | |
1517 | } | |
1518 | exit: | |
1519 | return ret; | |
1520 | } | |
1521 | ||
d7aaba14 | 1522 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1523 | void *data, |
1524 | int (*match)(struct lock_list *entry, void *data), | |
1525 | struct lock_list **target_entry) | |
c94aa5ca | 1526 | { |
77a80692 YD |
1527 | return __bfs(src_entry, data, match, target_entry, |
1528 | offsetof(struct lock_class, locks_after)); | |
c94aa5ca ML |
1529 | |
1530 | } | |
1531 | ||
d7aaba14 | 1532 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1533 | void *data, |
1534 | int (*match)(struct lock_list *entry, void *data), | |
1535 | struct lock_list **target_entry) | |
c94aa5ca | 1536 | { |
77a80692 YD |
1537 | return __bfs(src_entry, data, match, target_entry, |
1538 | offsetof(struct lock_class, locks_before)); | |
c94aa5ca ML |
1539 | |
1540 | } | |
1541 | ||
12593b74 BVA |
1542 | static void print_lock_trace(const struct lock_trace *trace, |
1543 | unsigned int spaces) | |
c120bce7 | 1544 | { |
12593b74 | 1545 | stack_trace_print(trace->entries, trace->nr_entries, spaces); |
c120bce7 TG |
1546 | } |
1547 | ||
8e18257d PZ |
1548 | /* |
1549 | * Print a dependency chain entry (this is only done when a deadlock | |
1550 | * has been detected): | |
1551 | */ | |
f7c1c6b3 | 1552 | static noinline void |
24208ca7 | 1553 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1554 | { |
1555 | if (debug_locks_silent) | |
f7c1c6b3 | 1556 | return; |
8e18257d PZ |
1557 | printk("\n-> #%u", depth); |
1558 | print_lock_name(target->class); | |
f943fe0f | 1559 | printk(KERN_CONT ":\n"); |
12593b74 | 1560 | print_lock_trace(target->trace, 6); |
8e18257d PZ |
1561 | } |
1562 | ||
f4185812 SR |
1563 | static void |
1564 | print_circular_lock_scenario(struct held_lock *src, | |
1565 | struct held_lock *tgt, | |
1566 | struct lock_list *prt) | |
1567 | { | |
1568 | struct lock_class *source = hlock_class(src); | |
1569 | struct lock_class *target = hlock_class(tgt); | |
1570 | struct lock_class *parent = prt->class; | |
1571 | ||
1572 | /* | |
1573 | * A direct locking problem where unsafe_class lock is taken | |
1574 | * directly by safe_class lock, then all we need to show | |
1575 | * is the deadlock scenario, as it is obvious that the | |
1576 | * unsafe lock is taken under the safe lock. | |
1577 | * | |
1578 | * But if there is a chain instead, where the safe lock takes | |
1579 | * an intermediate lock (middle_class) where this lock is | |
1580 | * not the same as the safe lock, then the lock chain is | |
1581 | * used to describe the problem. Otherwise we would need | |
1582 | * to show a different CPU case for each link in the chain | |
1583 | * from the safe_class lock to the unsafe_class lock. | |
1584 | */ | |
1585 | if (parent != source) { | |
1586 | printk("Chain exists of:\n "); | |
1587 | __print_lock_name(source); | |
f943fe0f | 1588 | printk(KERN_CONT " --> "); |
f4185812 | 1589 | __print_lock_name(parent); |
f943fe0f | 1590 | printk(KERN_CONT " --> "); |
f4185812 | 1591 | __print_lock_name(target); |
f943fe0f | 1592 | printk(KERN_CONT "\n\n"); |
f4185812 SR |
1593 | } |
1594 | ||
e966eaee IM |
1595 | printk(" Possible unsafe locking scenario:\n\n"); |
1596 | printk(" CPU0 CPU1\n"); | |
1597 | printk(" ---- ----\n"); | |
1598 | printk(" lock("); | |
1599 | __print_lock_name(target); | |
1600 | printk(KERN_CONT ");\n"); | |
1601 | printk(" lock("); | |
1602 | __print_lock_name(parent); | |
1603 | printk(KERN_CONT ");\n"); | |
1604 | printk(" lock("); | |
1605 | __print_lock_name(target); | |
1606 | printk(KERN_CONT ");\n"); | |
1607 | printk(" lock("); | |
1608 | __print_lock_name(source); | |
1609 | printk(KERN_CONT ");\n"); | |
1610 | printk("\n *** DEADLOCK ***\n\n"); | |
f4185812 SR |
1611 | } |
1612 | ||
8e18257d PZ |
1613 | /* |
1614 | * When a circular dependency is detected, print the | |
1615 | * header first: | |
1616 | */ | |
f7c1c6b3 | 1617 | static noinline void |
db0002a3 ML |
1618 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1619 | struct held_lock *check_src, | |
1620 | struct held_lock *check_tgt) | |
8e18257d PZ |
1621 | { |
1622 | struct task_struct *curr = current; | |
1623 | ||
c94aa5ca | 1624 | if (debug_locks_silent) |
f7c1c6b3 | 1625 | return; |
8e18257d | 1626 | |
681fbec8 | 1627 | pr_warn("\n"); |
a5dd63ef PM |
1628 | pr_warn("======================================================\n"); |
1629 | pr_warn("WARNING: possible circular locking dependency detected\n"); | |
fbdc4b9a | 1630 | print_kernel_ident(); |
a5dd63ef | 1631 | pr_warn("------------------------------------------------------\n"); |
681fbec8 | 1632 | pr_warn("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1633 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1634 | print_lock(check_src); |
383a4bc8 | 1635 | |
e966eaee | 1636 | pr_warn("\nbut task is already holding lock:\n"); |
383a4bc8 | 1637 | |
db0002a3 | 1638 | print_lock(check_tgt); |
681fbec8 PM |
1639 | pr_warn("\nwhich lock already depends on the new lock.\n\n"); |
1640 | pr_warn("\nthe existing dependency chain (in reverse order) is:\n"); | |
8e18257d PZ |
1641 | |
1642 | print_circular_bug_entry(entry, depth); | |
8e18257d PZ |
1643 | } |
1644 | ||
9e2d551e ML |
1645 | static inline int class_equal(struct lock_list *entry, void *data) |
1646 | { | |
1647 | return entry->class == data; | |
1648 | } | |
1649 | ||
f7c1c6b3 YD |
1650 | static noinline void print_circular_bug(struct lock_list *this, |
1651 | struct lock_list *target, | |
1652 | struct held_lock *check_src, | |
1653 | struct held_lock *check_tgt) | |
8e18257d PZ |
1654 | { |
1655 | struct task_struct *curr = current; | |
c94aa5ca | 1656 | struct lock_list *parent; |
f4185812 | 1657 | struct lock_list *first_parent; |
24208ca7 | 1658 | int depth; |
8e18257d | 1659 | |
c94aa5ca | 1660 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
f7c1c6b3 | 1661 | return; |
8e18257d | 1662 | |
12593b74 BVA |
1663 | this->trace = save_trace(); |
1664 | if (!this->trace) | |
f7c1c6b3 | 1665 | return; |
8e18257d | 1666 | |
c94aa5ca ML |
1667 | depth = get_lock_depth(target); |
1668 | ||
db0002a3 | 1669 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1670 | |
1671 | parent = get_lock_parent(target); | |
f4185812 | 1672 | first_parent = parent; |
c94aa5ca ML |
1673 | |
1674 | while (parent) { | |
1675 | print_circular_bug_entry(parent, --depth); | |
1676 | parent = get_lock_parent(parent); | |
1677 | } | |
8e18257d PZ |
1678 | |
1679 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1680 | print_circular_lock_scenario(check_src, check_tgt, |
1681 | first_parent); | |
1682 | ||
8e18257d PZ |
1683 | lockdep_print_held_locks(curr); |
1684 | ||
1685 | printk("\nstack backtrace:\n"); | |
1686 | dump_stack(); | |
8e18257d PZ |
1687 | } |
1688 | ||
f7c1c6b3 | 1689 | static noinline void print_bfs_bug(int ret) |
db0002a3 ML |
1690 | { |
1691 | if (!debug_locks_off_graph_unlock()) | |
f7c1c6b3 | 1692 | return; |
db0002a3 | 1693 | |
0119fee4 PZ |
1694 | /* |
1695 | * Breadth-first-search failed, graph got corrupted? | |
1696 | */ | |
db0002a3 | 1697 | WARN(1, "lockdep bfs error:%d\n", ret); |
db0002a3 ML |
1698 | } |
1699 | ||
ef681026 | 1700 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1701 | { |
ef681026 ML |
1702 | (*(unsigned long *)data)++; |
1703 | return 0; | |
1704 | } | |
419ca3f1 | 1705 | |
5216d530 | 1706 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1707 | { |
1708 | unsigned long count = 0; | |
1709 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1710 | |
ef681026 | 1711 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1712 | |
ef681026 | 1713 | return count; |
419ca3f1 | 1714 | } |
419ca3f1 DM |
1715 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1716 | { | |
1717 | unsigned long ret, flags; | |
ef681026 ML |
1718 | struct lock_list this; |
1719 | ||
1720 | this.parent = NULL; | |
1721 | this.class = class; | |
419ca3f1 | 1722 | |
fcc784be | 1723 | raw_local_irq_save(flags); |
0199c4e6 | 1724 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1725 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1726 | arch_spin_unlock(&lockdep_lock); |
fcc784be | 1727 | raw_local_irq_restore(flags); |
419ca3f1 DM |
1728 | |
1729 | return ret; | |
1730 | } | |
1731 | ||
5216d530 | 1732 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1733 | { |
ef681026 ML |
1734 | unsigned long count = 0; |
1735 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1736 | |
ef681026 | 1737 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1738 | |
ef681026 | 1739 | return count; |
419ca3f1 DM |
1740 | } |
1741 | ||
1742 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1743 | { | |
1744 | unsigned long ret, flags; | |
ef681026 ML |
1745 | struct lock_list this; |
1746 | ||
1747 | this.parent = NULL; | |
1748 | this.class = class; | |
419ca3f1 | 1749 | |
fcc784be | 1750 | raw_local_irq_save(flags); |
0199c4e6 | 1751 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1752 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1753 | arch_spin_unlock(&lockdep_lock); |
fcc784be | 1754 | raw_local_irq_restore(flags); |
419ca3f1 DM |
1755 | |
1756 | return ret; | |
1757 | } | |
1758 | ||
8e18257d | 1759 | /* |
8c2c2b44 YD |
1760 | * Check that the dependency graph starting at <src> can lead to |
1761 | * <target> or not. Print an error and return 0 if it does. | |
8e18257d PZ |
1762 | */ |
1763 | static noinline int | |
8c2c2b44 YD |
1764 | check_path(struct lock_class *target, struct lock_list *src_entry, |
1765 | struct lock_list **target_entry) | |
8e18257d | 1766 | { |
8c2c2b44 YD |
1767 | int ret; |
1768 | ||
1769 | ret = __bfs_forwards(src_entry, (void *)target, class_equal, | |
1770 | target_entry); | |
1771 | ||
1772 | if (unlikely(ret < 0)) | |
1773 | print_bfs_bug(ret); | |
1774 | ||
1775 | return ret; | |
1776 | } | |
1777 | ||
1778 | /* | |
1779 | * Prove that the dependency graph starting at <src> can not | |
1780 | * lead to <target>. If it can, there is a circle when adding | |
1781 | * <target> -> <src> dependency. | |
1782 | * | |
1783 | * Print an error and return 0 if it does. | |
1784 | */ | |
1785 | static noinline int | |
1786 | check_noncircular(struct held_lock *src, struct held_lock *target, | |
12593b74 | 1787 | struct lock_trace **const trace) |
8c2c2b44 YD |
1788 | { |
1789 | int ret; | |
1790 | struct lock_list *uninitialized_var(target_entry); | |
1791 | struct lock_list src_entry = { | |
1792 | .class = hlock_class(src), | |
1793 | .parent = NULL, | |
1794 | }; | |
8e18257d | 1795 | |
bd6d29c2 | 1796 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1797 | |
8c2c2b44 | 1798 | ret = check_path(hlock_class(target), &src_entry, &target_entry); |
fbb9ce95 | 1799 | |
8c2c2b44 | 1800 | if (unlikely(!ret)) { |
12593b74 | 1801 | if (!*trace) { |
8c2c2b44 YD |
1802 | /* |
1803 | * If save_trace fails here, the printing might | |
1804 | * trigger a WARN but because of the !nr_entries it | |
1805 | * should not do bad things. | |
1806 | */ | |
12593b74 | 1807 | *trace = save_trace(); |
8c2c2b44 YD |
1808 | } |
1809 | ||
1810 | print_circular_bug(&src_entry, target_entry, src, target); | |
1811 | } | |
1812 | ||
1813 | return ret; | |
db0002a3 | 1814 | } |
c94aa5ca | 1815 | |
68e9dc29 | 1816 | #ifdef CONFIG_LOCKDEP_SMALL |
8c2c2b44 YD |
1817 | /* |
1818 | * Check that the dependency graph starting at <src> can lead to | |
1819 | * <target> or not. If it can, <src> -> <target> dependency is already | |
1820 | * in the graph. | |
1821 | * | |
1822 | * Print an error and return 2 if it does or 1 if it does not. | |
1823 | */ | |
ae813308 | 1824 | static noinline int |
8c2c2b44 | 1825 | check_redundant(struct held_lock *src, struct held_lock *target) |
ae813308 | 1826 | { |
8c2c2b44 YD |
1827 | int ret; |
1828 | struct lock_list *uninitialized_var(target_entry); | |
1829 | struct lock_list src_entry = { | |
1830 | .class = hlock_class(src), | |
1831 | .parent = NULL, | |
1832 | }; | |
ae813308 PZ |
1833 | |
1834 | debug_atomic_inc(nr_redundant_checks); | |
1835 | ||
8c2c2b44 | 1836 | ret = check_path(hlock_class(target), &src_entry, &target_entry); |
ae813308 | 1837 | |
8c2c2b44 YD |
1838 | if (!ret) { |
1839 | debug_atomic_inc(nr_redundant); | |
1840 | ret = 2; | |
1841 | } else if (ret < 0) | |
1842 | ret = 0; | |
1843 | ||
1844 | return ret; | |
ae813308 | 1845 | } |
68e9dc29 | 1846 | #endif |
ae813308 | 1847 | |
e7a38f63 | 1848 | #ifdef CONFIG_TRACE_IRQFLAGS |
948f8376 FW |
1849 | |
1850 | static inline int usage_accumulate(struct lock_list *entry, void *mask) | |
1851 | { | |
1852 | *(unsigned long *)mask |= entry->class->usage_mask; | |
1853 | ||
1854 | return 0; | |
1855 | } | |
1856 | ||
fbb9ce95 IM |
1857 | /* |
1858 | * Forwards and backwards subgraph searching, for the purposes of | |
1859 | * proving that two subgraphs can be connected by a new dependency | |
1860 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1861 | */ | |
fbb9ce95 | 1862 | |
627f364d | 1863 | static inline int usage_match(struct lock_list *entry, void *mask) |
d7aaba14 | 1864 | { |
627f364d | 1865 | return entry->class->usage_mask & *(unsigned long *)mask; |
d7aaba14 ML |
1866 | } |
1867 | ||
fbb9ce95 IM |
1868 | /* |
1869 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1870 | * at @root->class that matches @bit. |
fbb9ce95 | 1871 | * |
d7aaba14 ML |
1872 | * Return 0 if such a node exists in the subgraph, and put that node |
1873 | * into *@target_entry. | |
fbb9ce95 | 1874 | * |
d7aaba14 ML |
1875 | * Return 1 otherwise and keep *@target_entry unchanged. |
1876 | * Return <0 on error. | |
fbb9ce95 | 1877 | */ |
d7aaba14 | 1878 | static int |
627f364d | 1879 | find_usage_forwards(struct lock_list *root, unsigned long usage_mask, |
d7aaba14 | 1880 | struct lock_list **target_entry) |
fbb9ce95 | 1881 | { |
d7aaba14 | 1882 | int result; |
fbb9ce95 | 1883 | |
bd6d29c2 | 1884 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1885 | |
627f364d | 1886 | result = __bfs_forwards(root, &usage_mask, usage_match, target_entry); |
d7aaba14 ML |
1887 | |
1888 | return result; | |
fbb9ce95 IM |
1889 | } |
1890 | ||
1891 | /* | |
1892 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1893 | * at @root->class that matches @bit. |
fbb9ce95 | 1894 | * |
d7aaba14 ML |
1895 | * Return 0 if such a node exists in the subgraph, and put that node |
1896 | * into *@target_entry. | |
fbb9ce95 | 1897 | * |
d7aaba14 ML |
1898 | * Return 1 otherwise and keep *@target_entry unchanged. |
1899 | * Return <0 on error. | |
fbb9ce95 | 1900 | */ |
d7aaba14 | 1901 | static int |
627f364d | 1902 | find_usage_backwards(struct lock_list *root, unsigned long usage_mask, |
d7aaba14 | 1903 | struct lock_list **target_entry) |
fbb9ce95 | 1904 | { |
d7aaba14 | 1905 | int result; |
fbb9ce95 | 1906 | |
bd6d29c2 | 1907 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1908 | |
627f364d | 1909 | result = __bfs_backwards(root, &usage_mask, usage_match, target_entry); |
f82b217e | 1910 | |
d7aaba14 | 1911 | return result; |
fbb9ce95 IM |
1912 | } |
1913 | ||
af012961 PZ |
1914 | static void print_lock_class_header(struct lock_class *class, int depth) |
1915 | { | |
1916 | int bit; | |
1917 | ||
1918 | printk("%*s->", depth, ""); | |
1919 | print_lock_name(class); | |
8ca2b56c WL |
1920 | #ifdef CONFIG_DEBUG_LOCKDEP |
1921 | printk(KERN_CONT " ops: %lu", debug_class_ops_read(class)); | |
1922 | #endif | |
f943fe0f | 1923 | printk(KERN_CONT " {\n"); |
af012961 PZ |
1924 | |
1925 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1926 | if (class->usage_mask & (1 << bit)) { | |
1927 | int len = depth; | |
1928 | ||
1929 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
f943fe0f | 1930 | len += printk(KERN_CONT " at:\n"); |
12593b74 | 1931 | print_lock_trace(class->usage_traces[bit], len); |
af012961 PZ |
1932 | } |
1933 | } | |
1934 | printk("%*s }\n", depth, ""); | |
1935 | ||
04860d48 | 1936 | printk("%*s ... key at: [<%px>] %pS\n", |
f943fe0f | 1937 | depth, "", class->key, class->key); |
af012961 PZ |
1938 | } |
1939 | ||
1940 | /* | |
1941 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1942 | */ | |
1943 | static void __used | |
1944 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
f7c1c6b3 | 1945 | struct lock_list *root) |
af012961 PZ |
1946 | { |
1947 | struct lock_list *entry = leaf; | |
1948 | int depth; | |
1949 | ||
1950 | /*compute depth from generated tree by BFS*/ | |
1951 | depth = get_lock_depth(leaf); | |
1952 | ||
1953 | do { | |
1954 | print_lock_class_header(entry->class, depth); | |
1955 | printk("%*s ... acquired at:\n", depth, ""); | |
12593b74 | 1956 | print_lock_trace(entry->trace, 2); |
af012961 PZ |
1957 | printk("\n"); |
1958 | ||
1959 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1960 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1961 | break; |
1962 | } | |
1963 | ||
1964 | entry = get_lock_parent(entry); | |
1965 | depth--; | |
1966 | } while (entry && (depth >= 0)); | |
af012961 | 1967 | } |
d7aaba14 | 1968 | |
3003eba3 SR |
1969 | static void |
1970 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1971 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1972 | struct lock_class *prev_class, |
1973 | struct lock_class *next_class) | |
3003eba3 SR |
1974 | { |
1975 | struct lock_class *safe_class = safe_entry->class; | |
1976 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1977 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1978 | |
1979 | if (middle_class == safe_class) | |
dad3d743 | 1980 | middle_class = next_class; |
3003eba3 SR |
1981 | |
1982 | /* | |
1983 | * A direct locking problem where unsafe_class lock is taken | |
1984 | * directly by safe_class lock, then all we need to show | |
1985 | * is the deadlock scenario, as it is obvious that the | |
1986 | * unsafe lock is taken under the safe lock. | |
1987 | * | |
1988 | * But if there is a chain instead, where the safe lock takes | |
1989 | * an intermediate lock (middle_class) where this lock is | |
1990 | * not the same as the safe lock, then the lock chain is | |
1991 | * used to describe the problem. Otherwise we would need | |
1992 | * to show a different CPU case for each link in the chain | |
1993 | * from the safe_class lock to the unsafe_class lock. | |
1994 | */ | |
1995 | if (middle_class != unsafe_class) { | |
1996 | printk("Chain exists of:\n "); | |
1997 | __print_lock_name(safe_class); | |
f943fe0f | 1998 | printk(KERN_CONT " --> "); |
3003eba3 | 1999 | __print_lock_name(middle_class); |
f943fe0f | 2000 | printk(KERN_CONT " --> "); |
3003eba3 | 2001 | __print_lock_name(unsafe_class); |
f943fe0f | 2002 | printk(KERN_CONT "\n\n"); |
3003eba3 SR |
2003 | } |
2004 | ||
2005 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
2006 | printk(" CPU0 CPU1\n"); | |
2007 | printk(" ---- ----\n"); | |
2008 | printk(" lock("); | |
2009 | __print_lock_name(unsafe_class); | |
f943fe0f | 2010 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
2011 | printk(" local_irq_disable();\n"); |
2012 | printk(" lock("); | |
2013 | __print_lock_name(safe_class); | |
f943fe0f | 2014 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
2015 | printk(" lock("); |
2016 | __print_lock_name(middle_class); | |
f943fe0f | 2017 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
2018 | printk(" <Interrupt>\n"); |
2019 | printk(" lock("); | |
2020 | __print_lock_name(safe_class); | |
f943fe0f | 2021 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
2022 | printk("\n *** DEADLOCK ***\n\n"); |
2023 | } | |
2024 | ||
f7c1c6b3 | 2025 | static void |
fbb9ce95 | 2026 | print_bad_irq_dependency(struct task_struct *curr, |
24208ca7 ML |
2027 | struct lock_list *prev_root, |
2028 | struct lock_list *next_root, | |
2029 | struct lock_list *backwards_entry, | |
2030 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
2031 | struct held_lock *prev, |
2032 | struct held_lock *next, | |
2033 | enum lock_usage_bit bit1, | |
2034 | enum lock_usage_bit bit2, | |
2035 | const char *irqclass) | |
2036 | { | |
74c383f1 | 2037 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
f7c1c6b3 | 2038 | return; |
fbb9ce95 | 2039 | |
681fbec8 | 2040 | pr_warn("\n"); |
a5dd63ef PM |
2041 | pr_warn("=====================================================\n"); |
2042 | pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n", | |
fbb9ce95 | 2043 | irqclass, irqclass); |
fbdc4b9a | 2044 | print_kernel_ident(); |
a5dd63ef | 2045 | pr_warn("-----------------------------------------------------\n"); |
681fbec8 | 2046 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 2047 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
2048 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
2049 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
2050 | curr->hardirqs_enabled, | |
2051 | curr->softirqs_enabled); | |
2052 | print_lock(next); | |
2053 | ||
681fbec8 | 2054 | pr_warn("\nand this task is already holding:\n"); |
fbb9ce95 | 2055 | print_lock(prev); |
681fbec8 | 2056 | pr_warn("which would create a new lock dependency:\n"); |
f82b217e | 2057 | print_lock_name(hlock_class(prev)); |
681fbec8 | 2058 | pr_cont(" ->"); |
f82b217e | 2059 | print_lock_name(hlock_class(next)); |
681fbec8 | 2060 | pr_cont("\n"); |
fbb9ce95 | 2061 | |
681fbec8 | 2062 | pr_warn("\nbut this new dependency connects a %s-irq-safe lock:\n", |
fbb9ce95 | 2063 | irqclass); |
24208ca7 | 2064 | print_lock_name(backwards_entry->class); |
681fbec8 | 2065 | pr_warn("\n... which became %s-irq-safe at:\n", irqclass); |
fbb9ce95 | 2066 | |
12593b74 | 2067 | print_lock_trace(backwards_entry->class->usage_traces[bit1], 1); |
fbb9ce95 | 2068 | |
681fbec8 | 2069 | pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass); |
24208ca7 | 2070 | print_lock_name(forwards_entry->class); |
681fbec8 PM |
2071 | pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass); |
2072 | pr_warn("..."); | |
fbb9ce95 | 2073 | |
12593b74 | 2074 | print_lock_trace(forwards_entry->class->usage_traces[bit2], 1); |
fbb9ce95 | 2075 | |
681fbec8 | 2076 | pr_warn("\nother info that might help us debug this:\n\n"); |
dad3d743 SR |
2077 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
2078 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 2079 | |
fbb9ce95 IM |
2080 | lockdep_print_held_locks(curr); |
2081 | ||
681fbec8 | 2082 | pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass); |
12593b74 BVA |
2083 | prev_root->trace = save_trace(); |
2084 | if (!prev_root->trace) | |
f7c1c6b3 | 2085 | return; |
24208ca7 | 2086 | print_shortest_lock_dependencies(backwards_entry, prev_root); |
fbb9ce95 | 2087 | |
681fbec8 PM |
2088 | pr_warn("\nthe dependencies between the lock to be acquired"); |
2089 | pr_warn(" and %s-irq-unsafe lock:\n", irqclass); | |
12593b74 BVA |
2090 | next_root->trace = save_trace(); |
2091 | if (!next_root->trace) | |
f7c1c6b3 | 2092 | return; |
24208ca7 | 2093 | print_shortest_lock_dependencies(forwards_entry, next_root); |
fbb9ce95 | 2094 | |
681fbec8 | 2095 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 | 2096 | dump_stack(); |
fbb9ce95 IM |
2097 | } |
2098 | ||
4f367d8a PZ |
2099 | static const char *state_names[] = { |
2100 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 2101 | __stringify(__STATE), |
4f367d8a PZ |
2102 | #include "lockdep_states.h" |
2103 | #undef LOCKDEP_STATE | |
2104 | }; | |
2105 | ||
2106 | static const char *state_rnames[] = { | |
2107 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 2108 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
2109 | #include "lockdep_states.h" |
2110 | #undef LOCKDEP_STATE | |
2111 | }; | |
2112 | ||
2113 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 2114 | { |
c902a1e8 FW |
2115 | if (bit & LOCK_USAGE_READ_MASK) |
2116 | return state_rnames[bit >> LOCK_USAGE_DIR_MASK]; | |
2117 | else | |
2118 | return state_names[bit >> LOCK_USAGE_DIR_MASK]; | |
4f367d8a | 2119 | } |
8e18257d | 2120 | |
948f8376 FW |
2121 | /* |
2122 | * The bit number is encoded like: | |
2123 | * | |
2124 | * bit0: 0 exclusive, 1 read lock | |
2125 | * bit1: 0 used in irq, 1 irq enabled | |
2126 | * bit2-n: state | |
2127 | */ | |
4f367d8a PZ |
2128 | static int exclusive_bit(int new_bit) |
2129 | { | |
bba2a8f1 FW |
2130 | int state = new_bit & LOCK_USAGE_STATE_MASK; |
2131 | int dir = new_bit & LOCK_USAGE_DIR_MASK; | |
8e18257d PZ |
2132 | |
2133 | /* | |
4f367d8a | 2134 | * keep state, bit flip the direction and strip read. |
8e18257d | 2135 | */ |
bba2a8f1 | 2136 | return state | (dir ^ LOCK_USAGE_DIR_MASK); |
4f367d8a PZ |
2137 | } |
2138 | ||
948f8376 FW |
2139 | /* |
2140 | * Observe that when given a bitmask where each bitnr is encoded as above, a | |
2141 | * right shift of the mask transforms the individual bitnrs as -1 and | |
2142 | * conversely, a left shift transforms into +1 for the individual bitnrs. | |
2143 | * | |
2144 | * So for all bits whose number have LOCK_ENABLED_* set (bitnr1 == 1), we can | |
2145 | * create the mask with those bit numbers using LOCK_USED_IN_* (bitnr1 == 0) | |
2146 | * instead by subtracting the bit number by 2, or shifting the mask right by 2. | |
2147 | * | |
2148 | * Similarly, bitnr1 == 0 becomes bitnr1 == 1 by adding 2, or shifting left 2. | |
2149 | * | |
2150 | * So split the mask (note that LOCKF_ENABLED_IRQ_ALL|LOCKF_USED_IN_IRQ_ALL is | |
2151 | * all bits set) and recompose with bitnr1 flipped. | |
2152 | */ | |
2153 | static unsigned long invert_dir_mask(unsigned long mask) | |
2154 | { | |
2155 | unsigned long excl = 0; | |
2156 | ||
2157 | /* Invert dir */ | |
2158 | excl |= (mask & LOCKF_ENABLED_IRQ_ALL) >> LOCK_USAGE_DIR_MASK; | |
2159 | excl |= (mask & LOCKF_USED_IN_IRQ_ALL) << LOCK_USAGE_DIR_MASK; | |
2160 | ||
2161 | return excl; | |
2162 | } | |
2163 | ||
2164 | /* | |
2165 | * As above, we clear bitnr0 (LOCK_*_READ off) with bitmask ops. First, for all | |
2166 | * bits with bitnr0 set (LOCK_*_READ), add those with bitnr0 cleared (LOCK_*). | |
2167 | * And then mask out all bitnr0. | |
2168 | */ | |
2169 | static unsigned long exclusive_mask(unsigned long mask) | |
2170 | { | |
2171 | unsigned long excl = invert_dir_mask(mask); | |
2172 | ||
2173 | /* Strip read */ | |
2174 | excl |= (excl & LOCKF_IRQ_READ) >> LOCK_USAGE_READ_MASK; | |
2175 | excl &= ~LOCKF_IRQ_READ; | |
2176 | ||
2177 | return excl; | |
2178 | } | |
2179 | ||
2180 | /* | |
2181 | * Retrieve the _possible_ original mask to which @mask is | |
2182 | * exclusive. Ie: this is the opposite of exclusive_mask(). | |
2183 | * Note that 2 possible original bits can match an exclusive | |
2184 | * bit: one has LOCK_USAGE_READ_MASK set, the other has it | |
2185 | * cleared. So both are returned for each exclusive bit. | |
2186 | */ | |
2187 | static unsigned long original_mask(unsigned long mask) | |
2188 | { | |
2189 | unsigned long excl = invert_dir_mask(mask); | |
2190 | ||
2191 | /* Include read in existing usages */ | |
2192 | excl |= (excl & LOCKF_IRQ) << LOCK_USAGE_READ_MASK; | |
2193 | ||
2194 | return excl; | |
2195 | } | |
2196 | ||
2197 | /* | |
2198 | * Find the first pair of bit match between an original | |
2199 | * usage mask and an exclusive usage mask. | |
2200 | */ | |
2201 | static int find_exclusive_match(unsigned long mask, | |
2202 | unsigned long excl_mask, | |
2203 | enum lock_usage_bit *bitp, | |
2204 | enum lock_usage_bit *excl_bitp) | |
2205 | { | |
2206 | int bit, excl; | |
2207 | ||
2208 | for_each_set_bit(bit, &mask, LOCK_USED) { | |
2209 | excl = exclusive_bit(bit); | |
2210 | if (excl_mask & lock_flag(excl)) { | |
2211 | *bitp = bit; | |
2212 | *excl_bitp = excl; | |
2213 | return 0; | |
2214 | } | |
2215 | } | |
2216 | return -1; | |
2217 | } | |
2218 | ||
2219 | /* | |
2220 | * Prove that the new dependency does not connect a hardirq-safe(-read) | |
2221 | * lock with a hardirq-unsafe lock - to achieve this we search | |
2222 | * the backwards-subgraph starting at <prev>, and the | |
2223 | * forwards-subgraph starting at <next>: | |
2224 | */ | |
4f367d8a | 2225 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, |
948f8376 | 2226 | struct held_lock *next) |
4f367d8a | 2227 | { |
948f8376 FW |
2228 | unsigned long usage_mask = 0, forward_mask, backward_mask; |
2229 | enum lock_usage_bit forward_bit = 0, backward_bit = 0; | |
2230 | struct lock_list *uninitialized_var(target_entry1); | |
2231 | struct lock_list *uninitialized_var(target_entry); | |
2232 | struct lock_list this, that; | |
2233 | int ret; | |
2234 | ||
8e18257d | 2235 | /* |
948f8376 FW |
2236 | * Step 1: gather all hard/soft IRQs usages backward in an |
2237 | * accumulated usage mask. | |
8e18257d | 2238 | */ |
948f8376 FW |
2239 | this.parent = NULL; |
2240 | this.class = hlock_class(prev); | |
8e18257d | 2241 | |
948f8376 | 2242 | ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL); |
f7c1c6b3 YD |
2243 | if (ret < 0) { |
2244 | print_bfs_bug(ret); | |
2245 | return 0; | |
2246 | } | |
8e18257d | 2247 | |
948f8376 FW |
2248 | usage_mask &= LOCKF_USED_IN_IRQ_ALL; |
2249 | if (!usage_mask) | |
2250 | return 1; | |
4f367d8a | 2251 | |
cf40bd16 | 2252 | /* |
948f8376 FW |
2253 | * Step 2: find exclusive uses forward that match the previous |
2254 | * backward accumulated mask. | |
cf40bd16 | 2255 | */ |
948f8376 | 2256 | forward_mask = exclusive_mask(usage_mask); |
cf40bd16 | 2257 | |
948f8376 FW |
2258 | that.parent = NULL; |
2259 | that.class = hlock_class(next); | |
4f367d8a | 2260 | |
948f8376 | 2261 | ret = find_usage_forwards(&that, forward_mask, &target_entry1); |
f7c1c6b3 YD |
2262 | if (ret < 0) { |
2263 | print_bfs_bug(ret); | |
2264 | return 0; | |
2265 | } | |
948f8376 FW |
2266 | if (ret == 1) |
2267 | return ret; | |
cf40bd16 | 2268 | |
948f8376 FW |
2269 | /* |
2270 | * Step 3: we found a bad match! Now retrieve a lock from the backward | |
2271 | * list whose usage mask matches the exclusive usage mask from the | |
2272 | * lock found on the forward list. | |
2273 | */ | |
2274 | backward_mask = original_mask(target_entry1->class->usage_mask); | |
2275 | ||
2276 | ret = find_usage_backwards(&this, backward_mask, &target_entry); | |
f7c1c6b3 YD |
2277 | if (ret < 0) { |
2278 | print_bfs_bug(ret); | |
2279 | return 0; | |
2280 | } | |
948f8376 FW |
2281 | if (DEBUG_LOCKS_WARN_ON(ret == 1)) |
2282 | return 1; | |
2283 | ||
2284 | /* | |
2285 | * Step 4: narrow down to a pair of incompatible usage bits | |
2286 | * and report it. | |
2287 | */ | |
2288 | ret = find_exclusive_match(target_entry->class->usage_mask, | |
2289 | target_entry1->class->usage_mask, | |
2290 | &backward_bit, &forward_bit); | |
2291 | if (DEBUG_LOCKS_WARN_ON(ret == -1)) | |
2292 | return 1; | |
2293 | ||
f7c1c6b3 YD |
2294 | print_bad_irq_dependency(curr, &this, &that, |
2295 | target_entry, target_entry1, | |
2296 | prev, next, | |
2297 | backward_bit, forward_bit, | |
2298 | state_name(backward_bit)); | |
2299 | ||
2300 | return 0; | |
8e18257d PZ |
2301 | } |
2302 | ||
2303 | static void inc_chains(void) | |
2304 | { | |
2305 | if (current->hardirq_context) | |
2306 | nr_hardirq_chains++; | |
2307 | else { | |
2308 | if (current->softirq_context) | |
2309 | nr_softirq_chains++; | |
2310 | else | |
2311 | nr_process_chains++; | |
2312 | } | |
2313 | } | |
2314 | ||
2315 | #else | |
2316 | ||
948f8376 FW |
2317 | static inline int check_irq_usage(struct task_struct *curr, |
2318 | struct held_lock *prev, struct held_lock *next) | |
8e18257d PZ |
2319 | { |
2320 | return 1; | |
2321 | } | |
2322 | ||
2323 | static inline void inc_chains(void) | |
2324 | { | |
2325 | nr_process_chains++; | |
2326 | } | |
2327 | ||
e7a38f63 | 2328 | #endif /* CONFIG_TRACE_IRQFLAGS */ |
fbb9ce95 | 2329 | |
48702ecf | 2330 | static void |
f7c1c6b3 | 2331 | print_deadlock_scenario(struct held_lock *nxt, struct held_lock *prv) |
48702ecf SR |
2332 | { |
2333 | struct lock_class *next = hlock_class(nxt); | |
2334 | struct lock_class *prev = hlock_class(prv); | |
2335 | ||
2336 | printk(" Possible unsafe locking scenario:\n\n"); | |
2337 | printk(" CPU0\n"); | |
2338 | printk(" ----\n"); | |
2339 | printk(" lock("); | |
2340 | __print_lock_name(prev); | |
f943fe0f | 2341 | printk(KERN_CONT ");\n"); |
48702ecf SR |
2342 | printk(" lock("); |
2343 | __print_lock_name(next); | |
f943fe0f | 2344 | printk(KERN_CONT ");\n"); |
48702ecf SR |
2345 | printk("\n *** DEADLOCK ***\n\n"); |
2346 | printk(" May be due to missing lock nesting notation\n\n"); | |
2347 | } | |
2348 | ||
f7c1c6b3 | 2349 | static void |
fbb9ce95 IM |
2350 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, |
2351 | struct held_lock *next) | |
2352 | { | |
74c383f1 | 2353 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
f7c1c6b3 | 2354 | return; |
fbb9ce95 | 2355 | |
681fbec8 | 2356 | pr_warn("\n"); |
a5dd63ef PM |
2357 | pr_warn("============================================\n"); |
2358 | pr_warn("WARNING: possible recursive locking detected\n"); | |
fbdc4b9a | 2359 | print_kernel_ident(); |
a5dd63ef | 2360 | pr_warn("--------------------------------------------\n"); |
681fbec8 | 2361 | pr_warn("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 2362 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 2363 | print_lock(next); |
681fbec8 | 2364 | pr_warn("\nbut task is already holding lock:\n"); |
fbb9ce95 IM |
2365 | print_lock(prev); |
2366 | ||
681fbec8 | 2367 | pr_warn("\nother info that might help us debug this:\n"); |
48702ecf | 2368 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
2369 | lockdep_print_held_locks(curr); |
2370 | ||
681fbec8 | 2371 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 | 2372 | dump_stack(); |
fbb9ce95 IM |
2373 | } |
2374 | ||
2375 | /* | |
2376 | * Check whether we are holding such a class already. | |
2377 | * | |
2378 | * (Note that this has to be done separately, because the graph cannot | |
2379 | * detect such classes of deadlocks.) | |
2380 | * | |
2381 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
2382 | */ | |
2383 | static int | |
4609c4f9 | 2384 | check_deadlock(struct task_struct *curr, struct held_lock *next) |
fbb9ce95 IM |
2385 | { |
2386 | struct held_lock *prev; | |
7531e2f3 | 2387 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
2388 | int i; |
2389 | ||
2390 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2391 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
2392 | |
2393 | if (prev->instance == next->nest_lock) | |
2394 | nest = prev; | |
2395 | ||
f82b217e | 2396 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 2397 | continue; |
7531e2f3 | 2398 | |
fbb9ce95 IM |
2399 | /* |
2400 | * Allow read-after-read recursion of the same | |
6c9076ec | 2401 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 2402 | */ |
4609c4f9 | 2403 | if ((next->read == 2) && prev->read) |
fbb9ce95 | 2404 | return 2; |
7531e2f3 PZ |
2405 | |
2406 | /* | |
2407 | * We're holding the nest_lock, which serializes this lock's | |
2408 | * nesting behaviour. | |
2409 | */ | |
2410 | if (nest) | |
2411 | return 2; | |
2412 | ||
f7c1c6b3 YD |
2413 | print_deadlock_bug(curr, prev, next); |
2414 | return 0; | |
fbb9ce95 IM |
2415 | } |
2416 | return 1; | |
2417 | } | |
2418 | ||
2419 | /* | |
2420 | * There was a chain-cache miss, and we are about to add a new dependency | |
154f185e | 2421 | * to a previous lock. We validate the following rules: |
fbb9ce95 IM |
2422 | * |
2423 | * - would the adding of the <prev> -> <next> dependency create a | |
2424 | * circular dependency in the graph? [== circular deadlock] | |
2425 | * | |
2426 | * - does the new prev->next dependency connect any hardirq-safe lock | |
2427 | * (in the full backwards-subgraph starting at <prev>) with any | |
2428 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
2429 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
2430 | * | |
2431 | * - does the new prev->next dependency connect any softirq-safe lock | |
2432 | * (in the full backwards-subgraph starting at <prev>) with any | |
2433 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
2434 | * <next>)? [== illegal lock inversion with softirq contexts] | |
2435 | * | |
2436 | * any of these scenarios could lead to a deadlock. | |
2437 | * | |
2438 | * Then if all the validations pass, we add the forwards and backwards | |
2439 | * dependency. | |
2440 | */ | |
2441 | static int | |
2442 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
12593b74 BVA |
2443 | struct held_lock *next, int distance, |
2444 | struct lock_trace **const trace) | |
fbb9ce95 IM |
2445 | { |
2446 | struct lock_list *entry; | |
8b405d5c | 2447 | int ret; |
fbb9ce95 | 2448 | |
a0b0fd53 BVA |
2449 | if (!hlock_class(prev)->key || !hlock_class(next)->key) { |
2450 | /* | |
2451 | * The warning statements below may trigger a use-after-free | |
2452 | * of the class name. It is better to trigger a use-after free | |
2453 | * and to have the class name most of the time instead of not | |
2454 | * having the class name available. | |
2455 | */ | |
2456 | WARN_ONCE(!debug_locks_silent && !hlock_class(prev)->key, | |
2457 | "Detected use-after-free of lock class %px/%s\n", | |
2458 | hlock_class(prev), | |
2459 | hlock_class(prev)->name); | |
2460 | WARN_ONCE(!debug_locks_silent && !hlock_class(next)->key, | |
2461 | "Detected use-after-free of lock class %px/%s\n", | |
2462 | hlock_class(next), | |
2463 | hlock_class(next)->name); | |
2464 | return 2; | |
2465 | } | |
2466 | ||
fbb9ce95 IM |
2467 | /* |
2468 | * Prove that the new <prev> -> <next> dependency would not | |
2469 | * create a circular dependency in the graph. (We do this by | |
154f185e YD |
2470 | * a breadth-first search into the graph starting at <next>, |
2471 | * and check whether we can reach <prev>.) | |
fbb9ce95 | 2472 | * |
154f185e YD |
2473 | * The search is limited by the size of the circular queue (i.e., |
2474 | * MAX_CIRCULAR_QUEUE_SIZE) which keeps track of a breadth of nodes | |
2475 | * in the graph whose neighbours are to be checked. | |
fbb9ce95 | 2476 | */ |
8c2c2b44 YD |
2477 | ret = check_noncircular(next, prev, trace); |
2478 | if (unlikely(ret <= 0)) | |
f7c1c6b3 | 2479 | return 0; |
c94aa5ca | 2480 | |
948f8376 | 2481 | if (!check_irq_usage(curr, prev, next)) |
fbb9ce95 IM |
2482 | return 0; |
2483 | ||
fbb9ce95 IM |
2484 | /* |
2485 | * For recursive read-locks we do all the dependency checks, | |
2486 | * but we dont store read-triggered dependencies (only | |
2487 | * write-triggered dependencies). This ensures that only the | |
2488 | * write-side dependencies matter, and that if for example a | |
2489 | * write-lock never takes any other locks, then the reads are | |
2490 | * equivalent to a NOP. | |
2491 | */ | |
2492 | if (next->read == 2 || prev->read == 2) | |
2493 | return 1; | |
2494 | /* | |
2495 | * Is the <prev> -> <next> dependency already present? | |
2496 | * | |
2497 | * (this may occur even though this is a new chain: consider | |
2498 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
2499 | * chains - the second one will be new, but L1 already has | |
2500 | * L2 added to its dependency list, due to the first chain.) | |
2501 | */ | |
f82b217e DJ |
2502 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
2503 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
2504 | if (distance == 1) |
2505 | entry->distance = 1; | |
70911fdc | 2506 | return 1; |
068135e6 | 2507 | } |
fbb9ce95 IM |
2508 | } |
2509 | ||
68e9dc29 | 2510 | #ifdef CONFIG_LOCKDEP_SMALL |
ae813308 PZ |
2511 | /* |
2512 | * Is the <prev> -> <next> link redundant? | |
2513 | */ | |
8c2c2b44 YD |
2514 | ret = check_redundant(prev, next); |
2515 | if (ret != 1) | |
2516 | return ret; | |
68e9dc29 | 2517 | #endif |
ae813308 | 2518 | |
12593b74 BVA |
2519 | if (!*trace) { |
2520 | *trace = save_trace(); | |
2521 | if (!*trace) | |
2522 | return 0; | |
2523 | } | |
4726f2a6 | 2524 | |
fbb9ce95 IM |
2525 | /* |
2526 | * Ok, all validations passed, add the new lock | |
2527 | * to the previous lock's dependency list: | |
2528 | */ | |
86cffb80 | 2529 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
f82b217e | 2530 | &hlock_class(prev)->locks_after, |
12593b74 | 2531 | next->acquire_ip, distance, *trace); |
068135e6 | 2532 | |
fbb9ce95 IM |
2533 | if (!ret) |
2534 | return 0; | |
910b1b2e | 2535 | |
86cffb80 | 2536 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
f82b217e | 2537 | &hlock_class(next)->locks_before, |
12593b74 | 2538 | next->acquire_ip, distance, *trace); |
910b1b2e JP |
2539 | if (!ret) |
2540 | return 0; | |
fbb9ce95 | 2541 | |
70911fdc | 2542 | return 2; |
8e18257d | 2543 | } |
fbb9ce95 | 2544 | |
8e18257d PZ |
2545 | /* |
2546 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
2547 | * The ones that are relevant are (in increasing distance from curr): | |
2548 | * all consecutive trylock entries and the final non-trylock entry - or | |
2549 | * the end of this context's lock-chain - whichever comes first. | |
2550 | */ | |
2551 | static int | |
2552 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
2553 | { | |
12593b74 | 2554 | struct lock_trace *trace = NULL; |
8e18257d PZ |
2555 | int depth = curr->lockdep_depth; |
2556 | struct held_lock *hlock; | |
d6d897ce | 2557 | |
fbb9ce95 | 2558 | /* |
8e18257d PZ |
2559 | * Debugging checks. |
2560 | * | |
2561 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 2562 | */ |
8e18257d PZ |
2563 | if (!depth) |
2564 | goto out_bug; | |
fbb9ce95 | 2565 | /* |
8e18257d PZ |
2566 | * At least two relevant locks must exist for this |
2567 | * to be a head: | |
fbb9ce95 | 2568 | */ |
8e18257d PZ |
2569 | if (curr->held_locks[depth].irq_context != |
2570 | curr->held_locks[depth-1].irq_context) | |
2571 | goto out_bug; | |
74c383f1 | 2572 | |
8e18257d PZ |
2573 | for (;;) { |
2574 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 2575 | hlock = curr->held_locks + depth - 1; |
e966eaee | 2576 | |
8e18257d | 2577 | /* |
e966eaee IM |
2578 | * Only non-recursive-read entries get new dependencies |
2579 | * added: | |
8e18257d | 2580 | */ |
e966eaee | 2581 | if (hlock->read != 2 && hlock->check) { |
76b14436 TG |
2582 | int ret = check_prev_add(curr, hlock, next, distance, |
2583 | &trace); | |
e966eaee IM |
2584 | if (!ret) |
2585 | return 0; | |
2586 | ||
ce07a941 | 2587 | /* |
e966eaee IM |
2588 | * Stop after the first non-trylock entry, |
2589 | * as non-trylock entries have added their | |
2590 | * own direct dependencies already, so this | |
2591 | * lock is connected to them indirectly: | |
ce07a941 | 2592 | */ |
e966eaee IM |
2593 | if (!hlock->trylock) |
2594 | break; | |
74c383f1 | 2595 | } |
e966eaee | 2596 | |
8e18257d PZ |
2597 | depth--; |
2598 | /* | |
2599 | * End of lock-stack? | |
2600 | */ | |
2601 | if (!depth) | |
2602 | break; | |
2603 | /* | |
2604 | * Stop the search if we cross into another context: | |
2605 | */ | |
2606 | if (curr->held_locks[depth].irq_context != | |
2607 | curr->held_locks[depth-1].irq_context) | |
2608 | break; | |
fbb9ce95 | 2609 | } |
8e18257d PZ |
2610 | return 1; |
2611 | out_bug: | |
2612 | if (!debug_locks_off_graph_unlock()) | |
2613 | return 0; | |
fbb9ce95 | 2614 | |
0119fee4 PZ |
2615 | /* |
2616 | * Clearly we all shouldn't be here, but since we made it we | |
2617 | * can reliable say we messed up our state. See the above two | |
2618 | * gotos for reasons why we could possibly end up here. | |
2619 | */ | |
8e18257d | 2620 | WARN_ON(1); |
fbb9ce95 | 2621 | |
8e18257d | 2622 | return 0; |
fbb9ce95 IM |
2623 | } |
2624 | ||
443cd507 | 2625 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
de4643a7 | 2626 | static DECLARE_BITMAP(lock_chains_in_use, MAX_LOCKDEP_CHAINS); |
cd1a28e8 | 2627 | int nr_chain_hlocks; |
443cd507 HY |
2628 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
2629 | ||
2630 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
2631 | { | |
2632 | return lock_classes + chain_hlocks[chain->base + i]; | |
2633 | } | |
8e18257d | 2634 | |
9e4e7554 IM |
2635 | /* |
2636 | * Returns the index of the first held_lock of the current chain | |
2637 | */ | |
2638 | static inline int get_first_held_lock(struct task_struct *curr, | |
2639 | struct held_lock *hlock) | |
2640 | { | |
2641 | int i; | |
2642 | struct held_lock *hlock_curr; | |
2643 | ||
2644 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2645 | hlock_curr = curr->held_locks + i; | |
2646 | if (hlock_curr->irq_context != hlock->irq_context) | |
2647 | break; | |
2648 | ||
2649 | } | |
2650 | ||
2651 | return ++i; | |
2652 | } | |
2653 | ||
5c8a010c | 2654 | #ifdef CONFIG_DEBUG_LOCKDEP |
39e2e173 AAF |
2655 | /* |
2656 | * Returns the next chain_key iteration | |
2657 | */ | |
2658 | static u64 print_chain_key_iteration(int class_idx, u64 chain_key) | |
2659 | { | |
2660 | u64 new_chain_key = iterate_chain_key(chain_key, class_idx); | |
2661 | ||
2662 | printk(" class_idx:%d -> chain_key:%016Lx", | |
2663 | class_idx, | |
2664 | (unsigned long long)new_chain_key); | |
2665 | return new_chain_key; | |
2666 | } | |
2667 | ||
2668 | static void | |
2669 | print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) | |
2670 | { | |
2671 | struct held_lock *hlock; | |
f6ec8829 | 2672 | u64 chain_key = INITIAL_CHAIN_KEY; |
39e2e173 | 2673 | int depth = curr->lockdep_depth; |
834494b2 | 2674 | int i = get_first_held_lock(curr, hlock_next); |
39e2e173 | 2675 | |
834494b2 YD |
2676 | printk("depth: %u (irq_context %u)\n", depth - i + 1, |
2677 | hlock_next->irq_context); | |
2678 | for (; i < depth; i++) { | |
39e2e173 AAF |
2679 | hlock = curr->held_locks + i; |
2680 | chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); | |
2681 | ||
2682 | print_lock(hlock); | |
2683 | } | |
2684 | ||
2685 | print_chain_key_iteration(hlock_next->class_idx, chain_key); | |
2686 | print_lock(hlock_next); | |
2687 | } | |
2688 | ||
2689 | static void print_chain_keys_chain(struct lock_chain *chain) | |
2690 | { | |
2691 | int i; | |
f6ec8829 | 2692 | u64 chain_key = INITIAL_CHAIN_KEY; |
39e2e173 AAF |
2693 | int class_id; |
2694 | ||
2695 | printk("depth: %u\n", chain->depth); | |
2696 | for (i = 0; i < chain->depth; i++) { | |
2697 | class_id = chain_hlocks[chain->base + i]; | |
01bb6f0a | 2698 | chain_key = print_chain_key_iteration(class_id, chain_key); |
39e2e173 AAF |
2699 | |
2700 | print_lock_name(lock_classes + class_id); | |
2701 | printk("\n"); | |
2702 | } | |
2703 | } | |
2704 | ||
2705 | static void print_collision(struct task_struct *curr, | |
2706 | struct held_lock *hlock_next, | |
2707 | struct lock_chain *chain) | |
2708 | { | |
681fbec8 | 2709 | pr_warn("\n"); |
a5dd63ef PM |
2710 | pr_warn("============================\n"); |
2711 | pr_warn("WARNING: chain_key collision\n"); | |
39e2e173 | 2712 | print_kernel_ident(); |
a5dd63ef | 2713 | pr_warn("----------------------------\n"); |
681fbec8 PM |
2714 | pr_warn("%s/%d: ", current->comm, task_pid_nr(current)); |
2715 | pr_warn("Hash chain already cached but the contents don't match!\n"); | |
39e2e173 | 2716 | |
681fbec8 | 2717 | pr_warn("Held locks:"); |
39e2e173 AAF |
2718 | print_chain_keys_held_locks(curr, hlock_next); |
2719 | ||
681fbec8 | 2720 | pr_warn("Locks in cached chain:"); |
39e2e173 AAF |
2721 | print_chain_keys_chain(chain); |
2722 | ||
681fbec8 | 2723 | pr_warn("\nstack backtrace:\n"); |
39e2e173 AAF |
2724 | dump_stack(); |
2725 | } | |
5c8a010c | 2726 | #endif |
39e2e173 | 2727 | |
9e4e7554 IM |
2728 | /* |
2729 | * Checks whether the chain and the current held locks are consistent | |
2730 | * in depth and also in content. If they are not it most likely means | |
2731 | * that there was a collision during the calculation of the chain_key. | |
2732 | * Returns: 0 not passed, 1 passed | |
2733 | */ | |
2734 | static int check_no_collision(struct task_struct *curr, | |
2735 | struct held_lock *hlock, | |
2736 | struct lock_chain *chain) | |
2737 | { | |
2738 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2739 | int i, j, id; | |
2740 | ||
2741 | i = get_first_held_lock(curr, hlock); | |
2742 | ||
39e2e173 AAF |
2743 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { |
2744 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2745 | return 0; |
39e2e173 | 2746 | } |
9e4e7554 IM |
2747 | |
2748 | for (j = 0; j < chain->depth - 1; j++, i++) { | |
01bb6f0a | 2749 | id = curr->held_locks[i].class_idx; |
9e4e7554 | 2750 | |
39e2e173 AAF |
2751 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { |
2752 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2753 | return 0; |
39e2e173 | 2754 | } |
9e4e7554 IM |
2755 | } |
2756 | #endif | |
2757 | return 1; | |
2758 | } | |
2759 | ||
2212684a BVA |
2760 | /* |
2761 | * Given an index that is >= -1, return the index of the next lock chain. | |
2762 | * Return -2 if there is no next lock chain. | |
2763 | */ | |
2764 | long lockdep_next_lockchain(long i) | |
2765 | { | |
de4643a7 BVA |
2766 | i = find_next_bit(lock_chains_in_use, ARRAY_SIZE(lock_chains), i + 1); |
2767 | return i < ARRAY_SIZE(lock_chains) ? i : -2; | |
2212684a BVA |
2768 | } |
2769 | ||
2770 | unsigned long lock_chain_count(void) | |
2771 | { | |
de4643a7 BVA |
2772 | return bitmap_weight(lock_chains_in_use, ARRAY_SIZE(lock_chains)); |
2773 | } | |
2774 | ||
2775 | /* Must be called with the graph lock held. */ | |
2776 | static struct lock_chain *alloc_lock_chain(void) | |
2777 | { | |
2778 | int idx = find_first_zero_bit(lock_chains_in_use, | |
2779 | ARRAY_SIZE(lock_chains)); | |
2780 | ||
2781 | if (unlikely(idx >= ARRAY_SIZE(lock_chains))) | |
2782 | return NULL; | |
2783 | __set_bit(idx, lock_chains_in_use); | |
2784 | return lock_chains + idx; | |
2212684a BVA |
2785 | } |
2786 | ||
fbb9ce95 | 2787 | /* |
545c23f2 BP |
2788 | * Adds a dependency chain into chain hashtable. And must be called with |
2789 | * graph_lock held. | |
2790 | * | |
2791 | * Return 0 if fail, and graph_lock is released. | |
2792 | * Return 1 if succeed, with graph_lock held. | |
fbb9ce95 | 2793 | */ |
545c23f2 BP |
2794 | static inline int add_chain_cache(struct task_struct *curr, |
2795 | struct held_lock *hlock, | |
2796 | u64 chain_key) | |
fbb9ce95 | 2797 | { |
f82b217e | 2798 | struct lock_class *class = hlock_class(hlock); |
a63f38cc | 2799 | struct hlist_head *hash_head = chainhashentry(chain_key); |
fbb9ce95 | 2800 | struct lock_chain *chain; |
e0944ee6 | 2801 | int i, j; |
fbb9ce95 | 2802 | |
0119fee4 | 2803 | /* |
527af3ea | 2804 | * The caller must hold the graph lock, ensure we've got IRQs |
0119fee4 PZ |
2805 | * disabled to make this an IRQ-safe lock.. for recursion reasons |
2806 | * lockdep won't complain about its own locking errors. | |
2807 | */ | |
381a2292 JP |
2808 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2809 | return 0; | |
9e4e7554 | 2810 | |
de4643a7 BVA |
2811 | chain = alloc_lock_chain(); |
2812 | if (!chain) { | |
74c383f1 IM |
2813 | if (!debug_locks_off_graph_unlock()) |
2814 | return 0; | |
2815 | ||
2c522836 | 2816 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2817 | dump_stack(); |
fbb9ce95 IM |
2818 | return 0; |
2819 | } | |
fbb9ce95 | 2820 | chain->chain_key = chain_key; |
443cd507 | 2821 | chain->irq_context = hlock->irq_context; |
9e4e7554 | 2822 | i = get_first_held_lock(curr, hlock); |
443cd507 | 2823 | chain->depth = curr->lockdep_depth + 1 - i; |
75dd602a PZ |
2824 | |
2825 | BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks)); | |
2826 | BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks)); | |
2827 | BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes)); | |
2828 | ||
e0944ee6 SR |
2829 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2830 | chain->base = nr_chain_hlocks; | |
443cd507 | 2831 | for (j = 0; j < chain->depth - 1; j++, i++) { |
01bb6f0a | 2832 | int lock_id = curr->held_locks[i].class_idx; |
443cd507 HY |
2833 | chain_hlocks[chain->base + j] = lock_id; |
2834 | } | |
2835 | chain_hlocks[chain->base + j] = class - lock_classes; | |
75dd602a | 2836 | nr_chain_hlocks += chain->depth; |
523b113b | 2837 | } else { |
f9af456a | 2838 | if (!debug_locks_off_graph_unlock()) |
75dd602a PZ |
2839 | return 0; |
2840 | ||
2841 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); | |
2842 | dump_stack(); | |
2843 | return 0; | |
2844 | } | |
75dd602a | 2845 | |
a63f38cc | 2846 | hlist_add_head_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2847 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2848 | inc_chains(); |
2849 | ||
2850 | return 1; | |
2851 | } | |
2852 | ||
545c23f2 | 2853 | /* |
a0b0fd53 BVA |
2854 | * Look up a dependency chain. Must be called with either the graph lock or |
2855 | * the RCU read lock held. | |
545c23f2 BP |
2856 | */ |
2857 | static inline struct lock_chain *lookup_chain_cache(u64 chain_key) | |
2858 | { | |
2859 | struct hlist_head *hash_head = chainhashentry(chain_key); | |
2860 | struct lock_chain *chain; | |
2861 | ||
545c23f2 | 2862 | hlist_for_each_entry_rcu(chain, hash_head, entry) { |
a0b0fd53 | 2863 | if (READ_ONCE(chain->chain_key) == chain_key) { |
545c23f2 BP |
2864 | debug_atomic_inc(chain_lookup_hits); |
2865 | return chain; | |
2866 | } | |
2867 | } | |
2868 | return NULL; | |
2869 | } | |
2870 | ||
2871 | /* | |
2872 | * If the key is not present yet in dependency chain cache then | |
2873 | * add it and return 1 - in this case the new dependency chain is | |
2874 | * validated. If the key is already hashed, return 0. | |
2875 | * (On return with 1 graph_lock is held.) | |
2876 | */ | |
2877 | static inline int lookup_chain_cache_add(struct task_struct *curr, | |
2878 | struct held_lock *hlock, | |
2879 | u64 chain_key) | |
2880 | { | |
2881 | struct lock_class *class = hlock_class(hlock); | |
2882 | struct lock_chain *chain = lookup_chain_cache(chain_key); | |
2883 | ||
2884 | if (chain) { | |
2885 | cache_hit: | |
2886 | if (!check_no_collision(curr, hlock, chain)) | |
2887 | return 0; | |
2888 | ||
2889 | if (very_verbose(class)) { | |
2890 | printk("\nhash chain already cached, key: " | |
04860d48 | 2891 | "%016Lx tail class: [%px] %s\n", |
545c23f2 BP |
2892 | (unsigned long long)chain_key, |
2893 | class->key, class->name); | |
2894 | } | |
2895 | ||
2896 | return 0; | |
2897 | } | |
2898 | ||
2899 | if (very_verbose(class)) { | |
04860d48 | 2900 | printk("\nnew hash chain, key: %016Lx tail class: [%px] %s\n", |
545c23f2 BP |
2901 | (unsigned long long)chain_key, class->key, class->name); |
2902 | } | |
2903 | ||
2904 | if (!graph_lock()) | |
2905 | return 0; | |
2906 | ||
2907 | /* | |
2908 | * We have to walk the chain again locked - to avoid duplicates: | |
2909 | */ | |
2910 | chain = lookup_chain_cache(chain_key); | |
2911 | if (chain) { | |
2912 | graph_unlock(); | |
2913 | goto cache_hit; | |
2914 | } | |
2915 | ||
2916 | if (!add_chain_cache(curr, hlock, chain_key)) | |
2917 | return 0; | |
2918 | ||
2919 | return 1; | |
2920 | } | |
2921 | ||
0b9fc8ec YD |
2922 | static int validate_chain(struct task_struct *curr, |
2923 | struct held_lock *hlock, | |
2924 | int chain_head, u64 chain_key) | |
8e18257d PZ |
2925 | { |
2926 | /* | |
2927 | * Trylock needs to maintain the stack of held locks, but it | |
2928 | * does not add new dependencies, because trylock can be done | |
2929 | * in any order. | |
2930 | * | |
2931 | * We look up the chain_key and do the O(N^2) check and update of | |
2932 | * the dependencies only if this is a new dependency chain. | |
545c23f2 | 2933 | * (If lookup_chain_cache_add() return with 1 it acquires |
8e18257d PZ |
2934 | * graph_lock for us) |
2935 | */ | |
fb9edbe9 | 2936 | if (!hlock->trylock && hlock->check && |
545c23f2 | 2937 | lookup_chain_cache_add(curr, hlock, chain_key)) { |
8e18257d PZ |
2938 | /* |
2939 | * Check whether last held lock: | |
2940 | * | |
2941 | * - is irq-safe, if this lock is irq-unsafe | |
2942 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2943 | * | |
2944 | * And check whether the new lock's dependency graph | |
31a490e5 | 2945 | * could lead back to the previous lock: |
8e18257d | 2946 | * |
31a490e5 YD |
2947 | * - within the current held-lock stack |
2948 | * - across our accumulated lock dependency records | |
2949 | * | |
2950 | * any of these scenarios could lead to a deadlock. | |
2951 | */ | |
2952 | /* | |
2953 | * The simple case: does the current hold the same lock | |
2954 | * already? | |
8e18257d | 2955 | */ |
4609c4f9 | 2956 | int ret = check_deadlock(curr, hlock); |
8e18257d PZ |
2957 | |
2958 | if (!ret) | |
2959 | return 0; | |
2960 | /* | |
2961 | * Mark recursive read, as we jump over it when | |
2962 | * building dependencies (just like we jump over | |
2963 | * trylock entries): | |
2964 | */ | |
2965 | if (ret == 2) | |
2966 | hlock->read = 2; | |
2967 | /* | |
2968 | * Add dependency only if this lock is not the head | |
2969 | * of the chain, and if it's not a secondary read-lock: | |
2970 | */ | |
545c23f2 | 2971 | if (!chain_head && ret != 2) { |
8e18257d PZ |
2972 | if (!check_prevs_add(curr, hlock)) |
2973 | return 0; | |
545c23f2 BP |
2974 | } |
2975 | ||
8e18257d | 2976 | graph_unlock(); |
545c23f2 BP |
2977 | } else { |
2978 | /* after lookup_chain_cache_add(): */ | |
8e18257d PZ |
2979 | if (unlikely(!debug_locks)) |
2980 | return 0; | |
545c23f2 | 2981 | } |
fbb9ce95 IM |
2982 | |
2983 | return 1; | |
2984 | } | |
8e18257d PZ |
2985 | #else |
2986 | static inline int validate_chain(struct task_struct *curr, | |
0b9fc8ec YD |
2987 | struct held_lock *hlock, |
2988 | int chain_head, u64 chain_key) | |
8e18257d PZ |
2989 | { |
2990 | return 1; | |
2991 | } | |
e7a38f63 | 2992 | #endif /* CONFIG_PROVE_LOCKING */ |
fbb9ce95 IM |
2993 | |
2994 | /* | |
2995 | * We are building curr_chain_key incrementally, so double-check | |
2996 | * it from scratch, to make sure that it's done correctly: | |
2997 | */ | |
1d09daa5 | 2998 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2999 | { |
3000 | #ifdef CONFIG_DEBUG_LOCKDEP | |
3001 | struct held_lock *hlock, *prev_hlock = NULL; | |
5f18ab5c | 3002 | unsigned int i; |
f6ec8829 | 3003 | u64 chain_key = INITIAL_CHAIN_KEY; |
fbb9ce95 IM |
3004 | |
3005 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3006 | hlock = curr->held_locks + i; | |
3007 | if (chain_key != hlock->prev_chain_key) { | |
3008 | debug_locks_off(); | |
0119fee4 PZ |
3009 | /* |
3010 | * We got mighty confused, our chain keys don't match | |
3011 | * with what we expect, someone trample on our task state? | |
3012 | */ | |
2df8b1d6 | 3013 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
3014 | curr->lockdep_depth, i, |
3015 | (unsigned long long)chain_key, | |
3016 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
3017 | return; |
3018 | } | |
01bb6f0a | 3019 | |
0119fee4 | 3020 | /* |
01bb6f0a YD |
3021 | * hlock->class_idx can't go beyond MAX_LOCKDEP_KEYS, but is |
3022 | * it registered lock class index? | |
0119fee4 | 3023 | */ |
01bb6f0a | 3024 | if (DEBUG_LOCKS_WARN_ON(!test_bit(hlock->class_idx, lock_classes_in_use))) |
381a2292 JP |
3025 | return; |
3026 | ||
fbb9ce95 IM |
3027 | if (prev_hlock && (prev_hlock->irq_context != |
3028 | hlock->irq_context)) | |
f6ec8829 | 3029 | chain_key = INITIAL_CHAIN_KEY; |
5f18ab5c | 3030 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
fbb9ce95 IM |
3031 | prev_hlock = hlock; |
3032 | } | |
3033 | if (chain_key != curr->curr_chain_key) { | |
3034 | debug_locks_off(); | |
0119fee4 PZ |
3035 | /* |
3036 | * More smoking hash instead of calculating it, damn see these | |
3037 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
3038 | */ | |
2df8b1d6 | 3039 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
3040 | curr->lockdep_depth, i, |
3041 | (unsigned long long)chain_key, | |
3042 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
3043 | } |
3044 | #endif | |
3045 | } | |
3046 | ||
30a35f79 | 3047 | #ifdef CONFIG_PROVE_LOCKING |
0d2cc3b3 FW |
3048 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
3049 | enum lock_usage_bit new_bit); | |
3050 | ||
f7c1c6b3 | 3051 | static void print_usage_bug_scenario(struct held_lock *lock) |
282b5c2f SR |
3052 | { |
3053 | struct lock_class *class = hlock_class(lock); | |
3054 | ||
3055 | printk(" Possible unsafe locking scenario:\n\n"); | |
3056 | printk(" CPU0\n"); | |
3057 | printk(" ----\n"); | |
3058 | printk(" lock("); | |
3059 | __print_lock_name(class); | |
f943fe0f | 3060 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
3061 | printk(" <Interrupt>\n"); |
3062 | printk(" lock("); | |
3063 | __print_lock_name(class); | |
f943fe0f | 3064 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
3065 | printk("\n *** DEADLOCK ***\n\n"); |
3066 | } | |
3067 | ||
f7c1c6b3 | 3068 | static void |
8e18257d PZ |
3069 | print_usage_bug(struct task_struct *curr, struct held_lock *this, |
3070 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
3071 | { | |
3072 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
f7c1c6b3 | 3073 | return; |
8e18257d | 3074 | |
681fbec8 | 3075 | pr_warn("\n"); |
a5dd63ef PM |
3076 | pr_warn("================================\n"); |
3077 | pr_warn("WARNING: inconsistent lock state\n"); | |
fbdc4b9a | 3078 | print_kernel_ident(); |
a5dd63ef | 3079 | pr_warn("--------------------------------\n"); |
8e18257d | 3080 | |
681fbec8 | 3081 | pr_warn("inconsistent {%s} -> {%s} usage.\n", |
8e18257d PZ |
3082 | usage_str[prev_bit], usage_str[new_bit]); |
3083 | ||
681fbec8 | 3084 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", |
ba25f9dc | 3085 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
3086 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
3087 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
3088 | trace_hardirqs_enabled(curr), | |
3089 | trace_softirqs_enabled(curr)); | |
3090 | print_lock(this); | |
3091 | ||
681fbec8 | 3092 | pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]); |
12593b74 | 3093 | print_lock_trace(hlock_class(this)->usage_traces[prev_bit], 1); |
8e18257d PZ |
3094 | |
3095 | print_irqtrace_events(curr); | |
681fbec8 | 3096 | pr_warn("\nother info that might help us debug this:\n"); |
282b5c2f SR |
3097 | print_usage_bug_scenario(this); |
3098 | ||
8e18257d PZ |
3099 | lockdep_print_held_locks(curr); |
3100 | ||
681fbec8 | 3101 | pr_warn("\nstack backtrace:\n"); |
8e18257d | 3102 | dump_stack(); |
8e18257d PZ |
3103 | } |
3104 | ||
3105 | /* | |
3106 | * Print out an error if an invalid bit is set: | |
3107 | */ | |
3108 | static inline int | |
3109 | valid_state(struct task_struct *curr, struct held_lock *this, | |
3110 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
3111 | { | |
f7c1c6b3 YD |
3112 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) { |
3113 | print_usage_bug(curr, this, bad_bit, new_bit); | |
3114 | return 0; | |
3115 | } | |
8e18257d PZ |
3116 | return 1; |
3117 | } | |
3118 | ||
fbb9ce95 IM |
3119 | |
3120 | /* | |
3121 | * print irq inversion bug: | |
3122 | */ | |
f7c1c6b3 | 3123 | static void |
24208ca7 ML |
3124 | print_irq_inversion_bug(struct task_struct *curr, |
3125 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
3126 | struct held_lock *this, int forwards, |
3127 | const char *irqclass) | |
3128 | { | |
dad3d743 SR |
3129 | struct lock_list *entry = other; |
3130 | struct lock_list *middle = NULL; | |
3131 | int depth; | |
3132 | ||
74c383f1 | 3133 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
f7c1c6b3 | 3134 | return; |
fbb9ce95 | 3135 | |
681fbec8 | 3136 | pr_warn("\n"); |
a5dd63ef PM |
3137 | pr_warn("========================================================\n"); |
3138 | pr_warn("WARNING: possible irq lock inversion dependency detected\n"); | |
fbdc4b9a | 3139 | print_kernel_ident(); |
a5dd63ef | 3140 | pr_warn("--------------------------------------------------------\n"); |
681fbec8 | 3141 | pr_warn("%s/%d just changed the state of lock:\n", |
ba25f9dc | 3142 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3143 | print_lock(this); |
3144 | if (forwards) | |
681fbec8 | 3145 | pr_warn("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 3146 | else |
681fbec8 | 3147 | pr_warn("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 3148 | print_lock_name(other->class); |
681fbec8 | 3149 | pr_warn("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
fbb9ce95 | 3150 | |
681fbec8 | 3151 | pr_warn("\nother info that might help us debug this:\n"); |
dad3d743 SR |
3152 | |
3153 | /* Find a middle lock (if one exists) */ | |
3154 | depth = get_lock_depth(other); | |
3155 | do { | |
3156 | if (depth == 0 && (entry != root)) { | |
681fbec8 | 3157 | pr_warn("lockdep:%s bad path found in chain graph\n", __func__); |
dad3d743 SR |
3158 | break; |
3159 | } | |
3160 | middle = entry; | |
3161 | entry = get_lock_parent(entry); | |
3162 | depth--; | |
3163 | } while (entry && entry != root && (depth >= 0)); | |
3164 | if (forwards) | |
3165 | print_irq_lock_scenario(root, other, | |
3166 | middle ? middle->class : root->class, other->class); | |
3167 | else | |
3168 | print_irq_lock_scenario(other, root, | |
3169 | middle ? middle->class : other->class, root->class); | |
3170 | ||
fbb9ce95 IM |
3171 | lockdep_print_held_locks(curr); |
3172 | ||
681fbec8 | 3173 | pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
12593b74 BVA |
3174 | root->trace = save_trace(); |
3175 | if (!root->trace) | |
f7c1c6b3 | 3176 | return; |
24208ca7 | 3177 | print_shortest_lock_dependencies(other, root); |
fbb9ce95 | 3178 | |
681fbec8 | 3179 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 | 3180 | dump_stack(); |
fbb9ce95 IM |
3181 | } |
3182 | ||
3183 | /* | |
3184 | * Prove that in the forwards-direction subgraph starting at <this> | |
3185 | * there is no lock matching <mask>: | |
3186 | */ | |
3187 | static int | |
3188 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
3189 | enum lock_usage_bit bit, const char *irqclass) | |
3190 | { | |
3191 | int ret; | |
d7aaba14 ML |
3192 | struct lock_list root; |
3193 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 3194 | |
d7aaba14 ML |
3195 | root.parent = NULL; |
3196 | root.class = hlock_class(this); | |
627f364d | 3197 | ret = find_usage_forwards(&root, lock_flag(bit), &target_entry); |
f7c1c6b3 YD |
3198 | if (ret < 0) { |
3199 | print_bfs_bug(ret); | |
3200 | return 0; | |
3201 | } | |
af012961 PZ |
3202 | if (ret == 1) |
3203 | return ret; | |
fbb9ce95 | 3204 | |
f7c1c6b3 YD |
3205 | print_irq_inversion_bug(curr, &root, target_entry, |
3206 | this, 1, irqclass); | |
3207 | return 0; | |
fbb9ce95 IM |
3208 | } |
3209 | ||
3210 | /* | |
3211 | * Prove that in the backwards-direction subgraph starting at <this> | |
3212 | * there is no lock matching <mask>: | |
3213 | */ | |
3214 | static int | |
3215 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
3216 | enum lock_usage_bit bit, const char *irqclass) | |
3217 | { | |
3218 | int ret; | |
d7aaba14 ML |
3219 | struct lock_list root; |
3220 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 3221 | |
d7aaba14 ML |
3222 | root.parent = NULL; |
3223 | root.class = hlock_class(this); | |
627f364d | 3224 | ret = find_usage_backwards(&root, lock_flag(bit), &target_entry); |
f7c1c6b3 YD |
3225 | if (ret < 0) { |
3226 | print_bfs_bug(ret); | |
3227 | return 0; | |
3228 | } | |
af012961 PZ |
3229 | if (ret == 1) |
3230 | return ret; | |
fbb9ce95 | 3231 | |
f7c1c6b3 YD |
3232 | print_irq_inversion_bug(curr, &root, target_entry, |
3233 | this, 0, irqclass); | |
3234 | return 0; | |
fbb9ce95 IM |
3235 | } |
3236 | ||
3117df04 | 3237 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
3238 | { |
3239 | printk("irq event stamp: %u\n", curr->irq_events); | |
04860d48 | 3240 | printk("hardirqs last enabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3241 | curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip, |
3242 | (void *)curr->hardirq_enable_ip); | |
04860d48 | 3243 | printk("hardirqs last disabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3244 | curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip, |
3245 | (void *)curr->hardirq_disable_ip); | |
04860d48 | 3246 | printk("softirqs last enabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3247 | curr->softirq_enable_event, (void *)curr->softirq_enable_ip, |
3248 | (void *)curr->softirq_enable_ip); | |
04860d48 | 3249 | printk("softirqs last disabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3250 | curr->softirq_disable_event, (void *)curr->softirq_disable_ip, |
3251 | (void *)curr->softirq_disable_ip); | |
fbb9ce95 IM |
3252 | } |
3253 | ||
cd95302d | 3254 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 3255 | { |
8e18257d PZ |
3256 | #if HARDIRQ_VERBOSE |
3257 | return class_filter(class); | |
3258 | #endif | |
fbb9ce95 IM |
3259 | return 0; |
3260 | } | |
3261 | ||
cd95302d | 3262 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 3263 | { |
8e18257d PZ |
3264 | #if SOFTIRQ_VERBOSE |
3265 | return class_filter(class); | |
3266 | #endif | |
3267 | return 0; | |
fbb9ce95 IM |
3268 | } |
3269 | ||
3270 | #define STRICT_READ_CHECKS 1 | |
3271 | ||
cd95302d PZ |
3272 | static int (*state_verbose_f[])(struct lock_class *class) = { |
3273 | #define LOCKDEP_STATE(__STATE) \ | |
3274 | __STATE##_verbose, | |
3275 | #include "lockdep_states.h" | |
3276 | #undef LOCKDEP_STATE | |
3277 | }; | |
3278 | ||
3279 | static inline int state_verbose(enum lock_usage_bit bit, | |
3280 | struct lock_class *class) | |
3281 | { | |
c902a1e8 | 3282 | return state_verbose_f[bit >> LOCK_USAGE_DIR_MASK](class); |
cd95302d PZ |
3283 | } |
3284 | ||
42c50d54 PZ |
3285 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
3286 | enum lock_usage_bit bit, const char *name); | |
3287 | ||
6a6904d3 | 3288 | static int |
1c21f14e PZ |
3289 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
3290 | enum lock_usage_bit new_bit) | |
6a6904d3 | 3291 | { |
f989209e | 3292 | int excl_bit = exclusive_bit(new_bit); |
bba2a8f1 FW |
3293 | int read = new_bit & LOCK_USAGE_READ_MASK; |
3294 | int dir = new_bit & LOCK_USAGE_DIR_MASK; | |
42c50d54 | 3295 | |
38aa2714 PZ |
3296 | /* |
3297 | * mark USED_IN has to look forwards -- to ensure no dependency | |
3298 | * has ENABLED state, which would allow recursion deadlocks. | |
3299 | * | |
3300 | * mark ENABLED has to look backwards -- to ensure no dependee | |
3301 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
3302 | */ | |
42c50d54 PZ |
3303 | check_usage_f usage = dir ? |
3304 | check_usage_backwards : check_usage_forwards; | |
f989209e | 3305 | |
38aa2714 PZ |
3306 | /* |
3307 | * Validate that this particular lock does not have conflicting | |
3308 | * usage states. | |
3309 | */ | |
6a6904d3 PZ |
3310 | if (!valid_state(curr, this, new_bit, excl_bit)) |
3311 | return 0; | |
42c50d54 | 3312 | |
38aa2714 PZ |
3313 | /* |
3314 | * Validate that the lock dependencies don't have conflicting usage | |
3315 | * states. | |
3316 | */ | |
bf998b98 | 3317 | if ((!read || STRICT_READ_CHECKS) && |
bba2a8f1 | 3318 | !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK))) |
6a6904d3 | 3319 | return 0; |
780e820b | 3320 | |
38aa2714 PZ |
3321 | /* |
3322 | * Check for read in write conflicts | |
3323 | */ | |
3324 | if (!read) { | |
bba2a8f1 | 3325 | if (!valid_state(curr, this, new_bit, excl_bit + LOCK_USAGE_READ_MASK)) |
38aa2714 PZ |
3326 | return 0; |
3327 | ||
3328 | if (STRICT_READ_CHECKS && | |
bba2a8f1 FW |
3329 | !usage(curr, this, excl_bit + LOCK_USAGE_READ_MASK, |
3330 | state_name(new_bit + LOCK_USAGE_READ_MASK))) | |
38aa2714 PZ |
3331 | return 0; |
3332 | } | |
780e820b | 3333 | |
cd95302d | 3334 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
3335 | return 2; |
3336 | ||
3337 | return 1; | |
3338 | } | |
3339 | ||
fbb9ce95 IM |
3340 | /* |
3341 | * Mark all held locks with a usage bit: | |
3342 | */ | |
1d09daa5 | 3343 | static int |
436a49ae | 3344 | mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit) |
fbb9ce95 | 3345 | { |
fbb9ce95 IM |
3346 | struct held_lock *hlock; |
3347 | int i; | |
3348 | ||
3349 | for (i = 0; i < curr->lockdep_depth; i++) { | |
436a49ae | 3350 | enum lock_usage_bit hlock_bit = base_bit; |
fbb9ce95 IM |
3351 | hlock = curr->held_locks + i; |
3352 | ||
cf2ad4d1 | 3353 | if (hlock->read) |
bba2a8f1 | 3354 | hlock_bit += LOCK_USAGE_READ_MASK; |
cf2ad4d1 | 3355 | |
436a49ae | 3356 | BUG_ON(hlock_bit >= LOCK_USAGE_STATES); |
cf40bd16 | 3357 | |
34d0ed5e | 3358 | if (!hlock->check) |
efbe2eee PZ |
3359 | continue; |
3360 | ||
436a49ae | 3361 | if (!mark_lock(curr, hlock, hlock_bit)) |
fbb9ce95 IM |
3362 | return 0; |
3363 | } | |
3364 | ||
3365 | return 1; | |
3366 | } | |
3367 | ||
fbb9ce95 IM |
3368 | /* |
3369 | * Hardirqs will be enabled: | |
3370 | */ | |
dd4e5d3a | 3371 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
3372 | { |
3373 | struct task_struct *curr = current; | |
fbb9ce95 | 3374 | |
fbb9ce95 IM |
3375 | /* we'll do an OFF -> ON transition: */ |
3376 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 3377 | |
fbb9ce95 IM |
3378 | /* |
3379 | * We are going to turn hardirqs on, so set the | |
3380 | * usage bit for all held locks: | |
3381 | */ | |
436a49ae | 3382 | if (!mark_held_locks(curr, LOCK_ENABLED_HARDIRQ)) |
fbb9ce95 IM |
3383 | return; |
3384 | /* | |
3385 | * If we have softirqs enabled, then set the usage | |
3386 | * bit for all held locks. (disabled hardirqs prevented | |
3387 | * this bit from being set before) | |
3388 | */ | |
3389 | if (curr->softirqs_enabled) | |
436a49ae | 3390 | if (!mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ)) |
fbb9ce95 IM |
3391 | return; |
3392 | ||
8e18257d PZ |
3393 | curr->hardirq_enable_ip = ip; |
3394 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 3395 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 3396 | } |
dd4e5d3a | 3397 | |
bff1b208 | 3398 | void lockdep_hardirqs_on(unsigned long ip) |
dd4e5d3a | 3399 | { |
dd4e5d3a PZ |
3400 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
3401 | return; | |
3402 | ||
7d36b26b PZ |
3403 | if (unlikely(current->hardirqs_enabled)) { |
3404 | /* | |
3405 | * Neither irq nor preemption are disabled here | |
3406 | * so this is racy by nature but losing one hit | |
3407 | * in a stat is not a big deal. | |
3408 | */ | |
3409 | __debug_atomic_inc(redundant_hardirqs_on); | |
3410 | return; | |
3411 | } | |
3412 | ||
0119fee4 PZ |
3413 | /* |
3414 | * We're enabling irqs and according to our state above irqs weren't | |
3415 | * already enabled, yet we find the hardware thinks they are in fact | |
3416 | * enabled.. someone messed up their IRQ state tracing. | |
3417 | */ | |
dd4e5d3a PZ |
3418 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3419 | return; | |
3420 | ||
0119fee4 PZ |
3421 | /* |
3422 | * See the fine text that goes along with this variable definition. | |
3423 | */ | |
d671002b | 3424 | if (DEBUG_LOCKS_WARN_ON(early_boot_irqs_disabled)) |
7d36b26b PZ |
3425 | return; |
3426 | ||
0119fee4 PZ |
3427 | /* |
3428 | * Can't allow enabling interrupts while in an interrupt handler, | |
3429 | * that's general bad form and such. Recursion, limited stack etc.. | |
3430 | */ | |
7d36b26b PZ |
3431 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
3432 | return; | |
3433 | ||
dd4e5d3a PZ |
3434 | current->lockdep_recursion = 1; |
3435 | __trace_hardirqs_on_caller(ip); | |
3436 | current->lockdep_recursion = 0; | |
3437 | } | |
2f43c602 | 3438 | NOKPROBE_SYMBOL(lockdep_hardirqs_on); |
8e18257d PZ |
3439 | |
3440 | /* | |
3441 | * Hardirqs were disabled: | |
3442 | */ | |
bff1b208 | 3443 | void lockdep_hardirqs_off(unsigned long ip) |
8e18257d PZ |
3444 | { |
3445 | struct task_struct *curr = current; | |
3446 | ||
3447 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
3448 | return; | |
3449 | ||
0119fee4 PZ |
3450 | /* |
3451 | * So we're supposed to get called after you mask local IRQs, but for | |
3452 | * some reason the hardware doesn't quite think you did a proper job. | |
3453 | */ | |
8e18257d PZ |
3454 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3455 | return; | |
3456 | ||
3457 | if (curr->hardirqs_enabled) { | |
3458 | /* | |
3459 | * We have done an ON -> OFF transition: | |
3460 | */ | |
3461 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 3462 | curr->hardirq_disable_ip = ip; |
8e18257d | 3463 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 3464 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 3465 | } else |
bd6d29c2 | 3466 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 3467 | } |
2f43c602 | 3468 | NOKPROBE_SYMBOL(lockdep_hardirqs_off); |
8e18257d PZ |
3469 | |
3470 | /* | |
3471 | * Softirqs will be enabled: | |
3472 | */ | |
3473 | void trace_softirqs_on(unsigned long ip) | |
3474 | { | |
3475 | struct task_struct *curr = current; | |
3476 | ||
dd4e5d3a | 3477 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
3478 | return; |
3479 | ||
0119fee4 PZ |
3480 | /* |
3481 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
3482 | * funny state and nesting things. | |
3483 | */ | |
8e18257d PZ |
3484 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3485 | return; | |
3486 | ||
3487 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 3488 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
3489 | return; |
3490 | } | |
3491 | ||
dd4e5d3a | 3492 | current->lockdep_recursion = 1; |
8e18257d PZ |
3493 | /* |
3494 | * We'll do an OFF -> ON transition: | |
3495 | */ | |
3496 | curr->softirqs_enabled = 1; | |
3497 | curr->softirq_enable_ip = ip; | |
3498 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 3499 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
3500 | /* |
3501 | * We are going to turn softirqs on, so set the | |
3502 | * usage bit for all held locks, if hardirqs are | |
3503 | * enabled too: | |
3504 | */ | |
3505 | if (curr->hardirqs_enabled) | |
436a49ae | 3506 | mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ); |
dd4e5d3a | 3507 | current->lockdep_recursion = 0; |
8e18257d PZ |
3508 | } |
3509 | ||
3510 | /* | |
3511 | * Softirqs were disabled: | |
3512 | */ | |
3513 | void trace_softirqs_off(unsigned long ip) | |
3514 | { | |
3515 | struct task_struct *curr = current; | |
3516 | ||
dd4e5d3a | 3517 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
3518 | return; |
3519 | ||
0119fee4 PZ |
3520 | /* |
3521 | * We fancy IRQs being disabled here, see softirq.c | |
3522 | */ | |
8e18257d PZ |
3523 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3524 | return; | |
3525 | ||
3526 | if (curr->softirqs_enabled) { | |
3527 | /* | |
3528 | * We have done an ON -> OFF transition: | |
3529 | */ | |
3530 | curr->softirqs_enabled = 0; | |
3531 | curr->softirq_disable_ip = ip; | |
3532 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 3533 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
3534 | /* |
3535 | * Whoops, we wanted softirqs off, so why aren't they? | |
3536 | */ | |
8e18257d PZ |
3537 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
3538 | } else | |
bd6d29c2 | 3539 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
3540 | } |
3541 | ||
09180651 YD |
3542 | static int |
3543 | mark_usage(struct task_struct *curr, struct held_lock *hlock, int check) | |
8e18257d | 3544 | { |
09180651 YD |
3545 | if (!check) |
3546 | goto lock_used; | |
3547 | ||
8e18257d PZ |
3548 | /* |
3549 | * If non-trylock use in a hardirq or softirq context, then | |
3550 | * mark the lock as used in these contexts: | |
3551 | */ | |
3552 | if (!hlock->trylock) { | |
3553 | if (hlock->read) { | |
3554 | if (curr->hardirq_context) | |
3555 | if (!mark_lock(curr, hlock, | |
3556 | LOCK_USED_IN_HARDIRQ_READ)) | |
3557 | return 0; | |
3558 | if (curr->softirq_context) | |
3559 | if (!mark_lock(curr, hlock, | |
3560 | LOCK_USED_IN_SOFTIRQ_READ)) | |
3561 | return 0; | |
3562 | } else { | |
3563 | if (curr->hardirq_context) | |
3564 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
3565 | return 0; | |
3566 | if (curr->softirq_context) | |
3567 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
3568 | return 0; | |
3569 | } | |
3570 | } | |
3571 | if (!hlock->hardirqs_off) { | |
3572 | if (hlock->read) { | |
3573 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3574 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
3575 | return 0; |
3576 | if (curr->softirqs_enabled) | |
3577 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3578 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
3579 | return 0; |
3580 | } else { | |
3581 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3582 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
3583 | return 0; |
3584 | if (curr->softirqs_enabled) | |
3585 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3586 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
3587 | return 0; |
3588 | } | |
3589 | } | |
3590 | ||
09180651 YD |
3591 | lock_used: |
3592 | /* mark it as used: */ | |
3593 | if (!mark_lock(curr, hlock, LOCK_USED)) | |
3594 | return 0; | |
3595 | ||
8e18257d PZ |
3596 | return 1; |
3597 | } | |
3598 | ||
c2469756 BF |
3599 | static inline unsigned int task_irq_context(struct task_struct *task) |
3600 | { | |
3601 | return 2 * !!task->hardirq_context + !!task->softirq_context; | |
3602 | } | |
3603 | ||
8e18257d PZ |
3604 | static int separate_irq_context(struct task_struct *curr, |
3605 | struct held_lock *hlock) | |
3606 | { | |
3607 | unsigned int depth = curr->lockdep_depth; | |
3608 | ||
3609 | /* | |
3610 | * Keep track of points where we cross into an interrupt context: | |
3611 | */ | |
8e18257d PZ |
3612 | if (depth) { |
3613 | struct held_lock *prev_hlock; | |
3614 | ||
3615 | prev_hlock = curr->held_locks + depth-1; | |
3616 | /* | |
3617 | * If we cross into another context, reset the | |
3618 | * hash key (this also prevents the checking and the | |
3619 | * adding of the dependency to 'prev'): | |
3620 | */ | |
3621 | if (prev_hlock->irq_context != hlock->irq_context) | |
3622 | return 1; | |
3623 | } | |
3624 | return 0; | |
fbb9ce95 IM |
3625 | } |
3626 | ||
fbb9ce95 | 3627 | /* |
8e18257d | 3628 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 3629 | */ |
1d09daa5 | 3630 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 3631 | enum lock_usage_bit new_bit) |
fbb9ce95 | 3632 | { |
8e18257d | 3633 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 | 3634 | |
4d56330d YD |
3635 | if (new_bit >= LOCK_USAGE_STATES) { |
3636 | DEBUG_LOCKS_WARN_ON(1); | |
3637 | return 0; | |
3638 | } | |
3639 | ||
fbb9ce95 | 3640 | /* |
8e18257d PZ |
3641 | * If already set then do not dirty the cacheline, |
3642 | * nor do any checks: | |
fbb9ce95 | 3643 | */ |
f82b217e | 3644 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
3645 | return 1; |
3646 | ||
3647 | if (!graph_lock()) | |
3648 | return 0; | |
fbb9ce95 | 3649 | /* |
25985edc | 3650 | * Make sure we didn't race: |
fbb9ce95 | 3651 | */ |
f82b217e | 3652 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
3653 | graph_unlock(); |
3654 | return 1; | |
3655 | } | |
fbb9ce95 | 3656 | |
f82b217e | 3657 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 3658 | |
12593b74 | 3659 | if (!(hlock_class(this)->usage_traces[new_bit] = save_trace())) |
8e18257d | 3660 | return 0; |
fbb9ce95 | 3661 | |
8e18257d | 3662 | switch (new_bit) { |
8e18257d | 3663 | case LOCK_USED: |
bd6d29c2 | 3664 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
3665 | break; |
3666 | default: | |
4d56330d YD |
3667 | ret = mark_lock_irq(curr, this, new_bit); |
3668 | if (!ret) | |
8e18257d | 3669 | return 0; |
8e18257d | 3670 | } |
fbb9ce95 | 3671 | |
8e18257d PZ |
3672 | graph_unlock(); |
3673 | ||
3674 | /* | |
3675 | * We must printk outside of the graph_lock: | |
3676 | */ | |
3677 | if (ret == 2) { | |
3678 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
3679 | print_lock(this); | |
3680 | print_irqtrace_events(curr); | |
3681 | dump_stack(); | |
3682 | } | |
3683 | ||
3684 | return ret; | |
3685 | } | |
fbb9ce95 | 3686 | |
30a35f79 | 3687 | #else /* CONFIG_PROVE_LOCKING */ |
886532ae AB |
3688 | |
3689 | static inline int | |
3690 | mark_usage(struct task_struct *curr, struct held_lock *hlock, int check) | |
3691 | { | |
3692 | return 1; | |
3693 | } | |
3694 | ||
3695 | static inline unsigned int task_irq_context(struct task_struct *task) | |
3696 | { | |
3697 | return 0; | |
3698 | } | |
3699 | ||
3700 | static inline int separate_irq_context(struct task_struct *curr, | |
3701 | struct held_lock *hlock) | |
3702 | { | |
3703 | return 0; | |
3704 | } | |
3705 | ||
30a35f79 | 3706 | #endif /* CONFIG_PROVE_LOCKING */ |
886532ae | 3707 | |
fbb9ce95 IM |
3708 | /* |
3709 | * Initialize a lock instance's lock-class mapping info: | |
3710 | */ | |
d35568bd | 3711 | void lockdep_init_map(struct lockdep_map *lock, const char *name, |
4dfbb9d8 | 3712 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 3713 | { |
d3d03d4f YZ |
3714 | int i; |
3715 | ||
d3d03d4f YZ |
3716 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) |
3717 | lock->class_cache[i] = NULL; | |
62016250 | 3718 | |
c8a25005 PZ |
3719 | #ifdef CONFIG_LOCK_STAT |
3720 | lock->cpu = raw_smp_processor_id(); | |
3721 | #endif | |
3722 | ||
0119fee4 PZ |
3723 | /* |
3724 | * Can't be having no nameless bastards around this place! | |
3725 | */ | |
c8a25005 PZ |
3726 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
3727 | lock->name = "NULL"; | |
fbb9ce95 | 3728 | return; |
c8a25005 PZ |
3729 | } |
3730 | ||
3731 | lock->name = name; | |
fbb9ce95 | 3732 | |
0119fee4 PZ |
3733 | /* |
3734 | * No key, no joy, we need to hash something. | |
3735 | */ | |
fbb9ce95 IM |
3736 | if (DEBUG_LOCKS_WARN_ON(!key)) |
3737 | return; | |
fbb9ce95 | 3738 | /* |
108c1485 BVA |
3739 | * Sanity check, the lock-class key must either have been allocated |
3740 | * statically or must have been registered as a dynamic key. | |
fbb9ce95 | 3741 | */ |
108c1485 BVA |
3742 | if (!static_obj(key) && !is_dynamic_key(key)) { |
3743 | if (debug_locks) | |
3744 | printk(KERN_ERR "BUG: key %px has not been registered!\n", key); | |
fbb9ce95 IM |
3745 | DEBUG_LOCKS_WARN_ON(1); |
3746 | return; | |
3747 | } | |
fbb9ce95 | 3748 | lock->key = key; |
c8a25005 PZ |
3749 | |
3750 | if (unlikely(!debug_locks)) | |
3751 | return; | |
3752 | ||
35a9393c PZ |
3753 | if (subclass) { |
3754 | unsigned long flags; | |
3755 | ||
3756 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3757 | return; | |
3758 | ||
3759 | raw_local_irq_save(flags); | |
3760 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3761 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3762 | current->lockdep_recursion = 0; |
3763 | raw_local_irq_restore(flags); | |
3764 | } | |
fbb9ce95 | 3765 | } |
fbb9ce95 IM |
3766 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3767 | ||
1704f47b | 3768 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3769 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3770 | |
f7c1c6b3 | 3771 | static void |
d0945950 ML |
3772 | print_lock_nested_lock_not_held(struct task_struct *curr, |
3773 | struct held_lock *hlock, | |
3774 | unsigned long ip) | |
3775 | { | |
3776 | if (!debug_locks_off()) | |
f7c1c6b3 | 3777 | return; |
d0945950 | 3778 | if (debug_locks_silent) |
f7c1c6b3 | 3779 | return; |
d0945950 | 3780 | |
681fbec8 | 3781 | pr_warn("\n"); |
a5dd63ef PM |
3782 | pr_warn("==================================\n"); |
3783 | pr_warn("WARNING: Nested lock was not taken\n"); | |
d0945950 | 3784 | print_kernel_ident(); |
a5dd63ef | 3785 | pr_warn("----------------------------------\n"); |
d0945950 | 3786 | |
681fbec8 | 3787 | pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); |
d0945950 ML |
3788 | print_lock(hlock); |
3789 | ||
681fbec8 PM |
3790 | pr_warn("\nbut this task is not holding:\n"); |
3791 | pr_warn("%s\n", hlock->nest_lock->name); | |
d0945950 | 3792 | |
681fbec8 | 3793 | pr_warn("\nstack backtrace:\n"); |
d0945950 ML |
3794 | dump_stack(); |
3795 | ||
681fbec8 | 3796 | pr_warn("\nother info that might help us debug this:\n"); |
d0945950 ML |
3797 | lockdep_print_held_locks(curr); |
3798 | ||
681fbec8 | 3799 | pr_warn("\nstack backtrace:\n"); |
d0945950 | 3800 | dump_stack(); |
d0945950 ML |
3801 | } |
3802 | ||
08f36ff6 | 3803 | static int __lock_is_held(const struct lockdep_map *lock, int read); |
d0945950 | 3804 | |
fbb9ce95 IM |
3805 | /* |
3806 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3807 | * We maintain the dependency maps and validate the locking attempt: | |
8ee10862 WL |
3808 | * |
3809 | * The callers must make sure that IRQs are disabled before calling it, | |
3810 | * otherwise we could get an interrupt which would want to take locks, | |
3811 | * which would end up in lockdep again. | |
fbb9ce95 IM |
3812 | */ |
3813 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3814 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3815 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3816 | int references, int pin_count) |
fbb9ce95 IM |
3817 | { |
3818 | struct task_struct *curr = current; | |
d6d897ce | 3819 | struct lock_class *class = NULL; |
fbb9ce95 | 3820 | struct held_lock *hlock; |
5f18ab5c | 3821 | unsigned int depth; |
fbb9ce95 | 3822 | int chain_head = 0; |
bb97a91e | 3823 | int class_idx; |
fbb9ce95 IM |
3824 | u64 chain_key; |
3825 | ||
3826 | if (unlikely(!debug_locks)) | |
3827 | return 0; | |
3828 | ||
fb9edbe9 ON |
3829 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3830 | check = 0; | |
1704f47b | 3831 | |
62016250 HM |
3832 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3833 | class = lock->class_cache[subclass]; | |
d6d897ce | 3834 | /* |
62016250 | 3835 | * Not cached? |
d6d897ce | 3836 | */ |
fbb9ce95 | 3837 | if (unlikely(!class)) { |
4dfbb9d8 | 3838 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3839 | if (!class) |
3840 | return 0; | |
3841 | } | |
8ca2b56c WL |
3842 | |
3843 | debug_class_ops_inc(class); | |
3844 | ||
fbb9ce95 | 3845 | if (very_verbose(class)) { |
04860d48 | 3846 | printk("\nacquire class [%px] %s", class->key, class->name); |
fbb9ce95 | 3847 | if (class->name_version > 1) |
f943fe0f DV |
3848 | printk(KERN_CONT "#%d", class->name_version); |
3849 | printk(KERN_CONT "\n"); | |
fbb9ce95 IM |
3850 | dump_stack(); |
3851 | } | |
3852 | ||
3853 | /* | |
3854 | * Add the lock to the list of currently held locks. | |
3855 | * (we dont increase the depth just yet, up until the | |
3856 | * dependency checks are done) | |
3857 | */ | |
3858 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3859 | /* |
3860 | * Ran out of static storage for our per-task lock stack again have we? | |
3861 | */ | |
fbb9ce95 IM |
3862 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3863 | return 0; | |
3864 | ||
01bb6f0a | 3865 | class_idx = class - lock_classes; |
bb97a91e | 3866 | |
e966eaee | 3867 | if (depth) { |
bb97a91e PZ |
3868 | hlock = curr->held_locks + depth - 1; |
3869 | if (hlock->class_idx == class_idx && nest_lock) { | |
d9349850 ID |
3870 | if (!references) |
3871 | references++; | |
7fb4a2ce | 3872 | |
d9349850 | 3873 | if (!hlock->references) |
bb97a91e | 3874 | hlock->references++; |
d9349850 ID |
3875 | |
3876 | hlock->references += references; | |
3877 | ||
3878 | /* Overflow */ | |
3879 | if (DEBUG_LOCKS_WARN_ON(hlock->references < references)) | |
3880 | return 0; | |
bb97a91e | 3881 | |
8c8889d8 | 3882 | return 2; |
bb97a91e PZ |
3883 | } |
3884 | } | |
3885 | ||
fbb9ce95 | 3886 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3887 | /* |
3888 | * Plain impossible, we just registered it and checked it weren't no | |
3889 | * NULL like.. I bet this mushroom I ate was good! | |
3890 | */ | |
f82b217e DJ |
3891 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3892 | return 0; | |
bb97a91e | 3893 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3894 | hlock->acquire_ip = ip; |
3895 | hlock->instance = lock; | |
7531e2f3 | 3896 | hlock->nest_lock = nest_lock; |
c2469756 | 3897 | hlock->irq_context = task_irq_context(curr); |
fbb9ce95 IM |
3898 | hlock->trylock = trylock; |
3899 | hlock->read = read; | |
3900 | hlock->check = check; | |
6951b12a | 3901 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3902 | hlock->references = references; |
f20786ff PZ |
3903 | #ifdef CONFIG_LOCK_STAT |
3904 | hlock->waittime_stamp = 0; | |
3365e779 | 3905 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3906 | #endif |
21199f27 | 3907 | hlock->pin_count = pin_count; |
fbb9ce95 | 3908 | |
09180651 YD |
3909 | /* Initialize the lock usage bit */ |
3910 | if (!mark_usage(curr, hlock, check)) | |
fbb9ce95 | 3911 | return 0; |
8e18257d | 3912 | |
fbb9ce95 | 3913 | /* |
17aacfb9 | 3914 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3915 | * lock keys along the dependency chain. We save the hash value |
3916 | * at every step so that we can get the current hash easily | |
3917 | * after unlock. The chain hash is then used to cache dependency | |
3918 | * results. | |
3919 | * | |
3920 | * The 'key ID' is what is the most compact key value to drive | |
3921 | * the hash, not class->key. | |
3922 | */ | |
0119fee4 | 3923 | /* |
01bb6f0a | 3924 | * Whoops, we did it again.. class_idx is invalid. |
0119fee4 | 3925 | */ |
01bb6f0a | 3926 | if (DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use))) |
fbb9ce95 IM |
3927 | return 0; |
3928 | ||
3929 | chain_key = curr->curr_chain_key; | |
3930 | if (!depth) { | |
0119fee4 PZ |
3931 | /* |
3932 | * How can we have a chain hash when we ain't got no keys?! | |
3933 | */ | |
f6ec8829 | 3934 | if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY)) |
fbb9ce95 IM |
3935 | return 0; |
3936 | chain_head = 1; | |
3937 | } | |
3938 | ||
3939 | hlock->prev_chain_key = chain_key; | |
8e18257d | 3940 | if (separate_irq_context(curr, hlock)) { |
f6ec8829 | 3941 | chain_key = INITIAL_CHAIN_KEY; |
8e18257d | 3942 | chain_head = 1; |
fbb9ce95 | 3943 | } |
5f18ab5c | 3944 | chain_key = iterate_chain_key(chain_key, class_idx); |
fbb9ce95 | 3945 | |
f7c1c6b3 YD |
3946 | if (nest_lock && !__lock_is_held(nest_lock, -1)) { |
3947 | print_lock_nested_lock_not_held(curr, hlock, ip); | |
3948 | return 0; | |
3949 | } | |
d0945950 | 3950 | |
a0b0fd53 BVA |
3951 | if (!debug_locks_silent) { |
3952 | WARN_ON_ONCE(depth && !hlock_class(hlock - 1)->key); | |
3953 | WARN_ON_ONCE(!hlock_class(hlock)->key); | |
3954 | } | |
3955 | ||
0b9fc8ec | 3956 | if (!validate_chain(curr, hlock, chain_head, chain_key)) |
8e18257d | 3957 | return 0; |
381a2292 | 3958 | |
3aa416b0 | 3959 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3960 | curr->lockdep_depth++; |
3961 | check_chain_key(curr); | |
60e114d1 JP |
3962 | #ifdef CONFIG_DEBUG_LOCKDEP |
3963 | if (unlikely(!debug_locks)) | |
3964 | return 0; | |
3965 | #endif | |
fbb9ce95 IM |
3966 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3967 | debug_locks_off(); | |
2c522836 DJ |
3968 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3969 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3970 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3971 | |
3972 | lockdep_print_held_locks(current); | |
3973 | debug_show_all_locks(); | |
eedeeabd | 3974 | dump_stack(); |
c0540606 | 3975 | |
fbb9ce95 IM |
3976 | return 0; |
3977 | } | |
381a2292 | 3978 | |
fbb9ce95 IM |
3979 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3980 | max_lockdep_depth = curr->lockdep_depth; | |
3981 | ||
3982 | return 1; | |
3983 | } | |
3984 | ||
f7c1c6b3 YD |
3985 | static void print_unlock_imbalance_bug(struct task_struct *curr, |
3986 | struct lockdep_map *lock, | |
3987 | unsigned long ip) | |
fbb9ce95 IM |
3988 | { |
3989 | if (!debug_locks_off()) | |
f7c1c6b3 | 3990 | return; |
fbb9ce95 | 3991 | if (debug_locks_silent) |
f7c1c6b3 | 3992 | return; |
fbb9ce95 | 3993 | |
681fbec8 | 3994 | pr_warn("\n"); |
a5dd63ef PM |
3995 | pr_warn("=====================================\n"); |
3996 | pr_warn("WARNING: bad unlock balance detected!\n"); | |
fbdc4b9a | 3997 | print_kernel_ident(); |
a5dd63ef | 3998 | pr_warn("-------------------------------------\n"); |
681fbec8 | 3999 | pr_warn("%s/%d is trying to release lock (", |
ba25f9dc | 4000 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 4001 | print_lockdep_cache(lock); |
681fbec8 | 4002 | pr_cont(") at:\n"); |
fbb9ce95 | 4003 | print_ip_sym(ip); |
681fbec8 PM |
4004 | pr_warn("but there are no more locks to release!\n"); |
4005 | pr_warn("\nother info that might help us debug this:\n"); | |
fbb9ce95 IM |
4006 | lockdep_print_held_locks(curr); |
4007 | ||
681fbec8 | 4008 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 | 4009 | dump_stack(); |
fbb9ce95 IM |
4010 | } |
4011 | ||
08f36ff6 MW |
4012 | static int match_held_lock(const struct held_lock *hlock, |
4013 | const struct lockdep_map *lock) | |
bb97a91e PZ |
4014 | { |
4015 | if (hlock->instance == lock) | |
4016 | return 1; | |
4017 | ||
4018 | if (hlock->references) { | |
08f36ff6 | 4019 | const struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
4020 | |
4021 | if (!class) | |
4022 | class = look_up_lock_class(lock, 0); | |
4023 | ||
80e0401e PZ |
4024 | /* |
4025 | * If look_up_lock_class() failed to find a class, we're trying | |
4026 | * to test if we hold a lock that has never yet been acquired. | |
4027 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
4028 | * holding it either, so report failure. | |
4029 | */ | |
64f29d1b | 4030 | if (!class) |
bb97a91e PZ |
4031 | return 0; |
4032 | ||
0119fee4 PZ |
4033 | /* |
4034 | * References, but not a lock we're actually ref-counting? | |
4035 | * State got messed up, follow the sites that change ->references | |
4036 | * and try to make sense of it. | |
4037 | */ | |
bb97a91e PZ |
4038 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
4039 | return 0; | |
4040 | ||
01bb6f0a | 4041 | if (hlock->class_idx == class - lock_classes) |
bb97a91e PZ |
4042 | return 1; |
4043 | } | |
4044 | ||
4045 | return 0; | |
4046 | } | |
4047 | ||
41c2c5b8 O |
4048 | /* @depth must not be zero */ |
4049 | static struct held_lock *find_held_lock(struct task_struct *curr, | |
4050 | struct lockdep_map *lock, | |
4051 | unsigned int depth, int *idx) | |
4052 | { | |
4053 | struct held_lock *ret, *hlock, *prev_hlock; | |
4054 | int i; | |
4055 | ||
4056 | i = depth - 1; | |
4057 | hlock = curr->held_locks + i; | |
4058 | ret = hlock; | |
4059 | if (match_held_lock(hlock, lock)) | |
4060 | goto out; | |
4061 | ||
4062 | ret = NULL; | |
4063 | for (i--, prev_hlock = hlock--; | |
4064 | i >= 0; | |
4065 | i--, prev_hlock = hlock--) { | |
4066 | /* | |
4067 | * We must not cross into another context: | |
4068 | */ | |
4069 | if (prev_hlock->irq_context != hlock->irq_context) { | |
4070 | ret = NULL; | |
4071 | break; | |
4072 | } | |
4073 | if (match_held_lock(hlock, lock)) { | |
4074 | ret = hlock; | |
4075 | break; | |
4076 | } | |
4077 | } | |
4078 | ||
4079 | out: | |
4080 | *idx = i; | |
4081 | return ret; | |
4082 | } | |
4083 | ||
e969970b | 4084 | static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, |
8c8889d8 | 4085 | int idx, unsigned int *merged) |
e969970b O |
4086 | { |
4087 | struct held_lock *hlock; | |
8c8889d8 | 4088 | int first_idx = idx; |
e969970b | 4089 | |
8ee10862 WL |
4090 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
4091 | return 0; | |
4092 | ||
e969970b | 4093 | for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) { |
8c8889d8 | 4094 | switch (__lock_acquire(hlock->instance, |
e969970b O |
4095 | hlock_class(hlock)->subclass, |
4096 | hlock->trylock, | |
4097 | hlock->read, hlock->check, | |
4098 | hlock->hardirqs_off, | |
4099 | hlock->nest_lock, hlock->acquire_ip, | |
8c8889d8 ID |
4100 | hlock->references, hlock->pin_count)) { |
4101 | case 0: | |
e969970b | 4102 | return 1; |
8c8889d8 ID |
4103 | case 1: |
4104 | break; | |
4105 | case 2: | |
4106 | *merged += (idx == first_idx); | |
4107 | break; | |
4108 | default: | |
4109 | WARN_ON(1); | |
4110 | return 0; | |
4111 | } | |
e969970b O |
4112 | } |
4113 | return 0; | |
4114 | } | |
4115 | ||
64aa348e | 4116 | static int |
00ef9f73 PZ |
4117 | __lock_set_class(struct lockdep_map *lock, const char *name, |
4118 | struct lock_class_key *key, unsigned int subclass, | |
4119 | unsigned long ip) | |
64aa348e PZ |
4120 | { |
4121 | struct task_struct *curr = current; | |
8c8889d8 | 4122 | unsigned int depth, merged = 0; |
41c2c5b8 | 4123 | struct held_lock *hlock; |
64aa348e | 4124 | struct lock_class *class; |
64aa348e PZ |
4125 | int i; |
4126 | ||
513e1073 WL |
4127 | if (unlikely(!debug_locks)) |
4128 | return 0; | |
4129 | ||
64aa348e | 4130 | depth = curr->lockdep_depth; |
0119fee4 PZ |
4131 | /* |
4132 | * This function is about (re)setting the class of a held lock, | |
4133 | * yet we're not actually holding any locks. Naughty user! | |
4134 | */ | |
64aa348e PZ |
4135 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4136 | return 0; | |
4137 | ||
41c2c5b8 | 4138 | hlock = find_held_lock(curr, lock, depth, &i); |
f7c1c6b3 YD |
4139 | if (!hlock) { |
4140 | print_unlock_imbalance_bug(curr, lock, ip); | |
4141 | return 0; | |
4142 | } | |
64aa348e | 4143 | |
00ef9f73 | 4144 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 4145 | class = register_lock_class(lock, subclass, 0); |
01bb6f0a | 4146 | hlock->class_idx = class - lock_classes; |
64aa348e PZ |
4147 | |
4148 | curr->lockdep_depth = i; | |
4149 | curr->curr_chain_key = hlock->prev_chain_key; | |
4150 | ||
8c8889d8 | 4151 | if (reacquire_held_locks(curr, depth, i, &merged)) |
e969970b | 4152 | return 0; |
64aa348e | 4153 | |
0119fee4 PZ |
4154 | /* |
4155 | * I took it apart and put it back together again, except now I have | |
4156 | * these 'spare' parts.. where shall I put them. | |
4157 | */ | |
8c8889d8 | 4158 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged)) |
64aa348e PZ |
4159 | return 0; |
4160 | return 1; | |
4161 | } | |
4162 | ||
6419c4af O |
4163 | static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
4164 | { | |
4165 | struct task_struct *curr = current; | |
8c8889d8 | 4166 | unsigned int depth, merged = 0; |
6419c4af | 4167 | struct held_lock *hlock; |
6419c4af O |
4168 | int i; |
4169 | ||
71492580 WL |
4170 | if (unlikely(!debug_locks)) |
4171 | return 0; | |
4172 | ||
6419c4af O |
4173 | depth = curr->lockdep_depth; |
4174 | /* | |
4175 | * This function is about (re)setting the class of a held lock, | |
4176 | * yet we're not actually holding any locks. Naughty user! | |
4177 | */ | |
4178 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
4179 | return 0; | |
4180 | ||
4181 | hlock = find_held_lock(curr, lock, depth, &i); | |
f7c1c6b3 YD |
4182 | if (!hlock) { |
4183 | print_unlock_imbalance_bug(curr, lock, ip); | |
4184 | return 0; | |
4185 | } | |
6419c4af O |
4186 | |
4187 | curr->lockdep_depth = i; | |
4188 | curr->curr_chain_key = hlock->prev_chain_key; | |
4189 | ||
4190 | WARN(hlock->read, "downgrading a read lock"); | |
4191 | hlock->read = 1; | |
4192 | hlock->acquire_ip = ip; | |
4193 | ||
8c8889d8 ID |
4194 | if (reacquire_held_locks(curr, depth, i, &merged)) |
4195 | return 0; | |
4196 | ||
4197 | /* Merging can't happen with unchanged classes.. */ | |
4198 | if (DEBUG_LOCKS_WARN_ON(merged)) | |
6419c4af O |
4199 | return 0; |
4200 | ||
4201 | /* | |
4202 | * I took it apart and put it back together again, except now I have | |
4203 | * these 'spare' parts.. where shall I put them. | |
4204 | */ | |
4205 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
4206 | return 0; | |
8c8889d8 | 4207 | |
6419c4af O |
4208 | return 1; |
4209 | } | |
4210 | ||
fbb9ce95 | 4211 | /* |
e0f56fd7 PZ |
4212 | * Remove the lock to the list of currently held locks - this gets |
4213 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
4214 | * mutex_lock_interruptible()). | |
4215 | * | |
4216 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
4217 | */ |
4218 | static int | |
b4adfe8e | 4219 | __lock_release(struct lockdep_map *lock, unsigned long ip) |
fbb9ce95 | 4220 | { |
e0f56fd7 | 4221 | struct task_struct *curr = current; |
8c8889d8 | 4222 | unsigned int depth, merged = 1; |
41c2c5b8 | 4223 | struct held_lock *hlock; |
e966eaee | 4224 | int i; |
fbb9ce95 | 4225 | |
e0f56fd7 PZ |
4226 | if (unlikely(!debug_locks)) |
4227 | return 0; | |
4228 | ||
fbb9ce95 | 4229 | depth = curr->lockdep_depth; |
0119fee4 PZ |
4230 | /* |
4231 | * So we're all set to release this lock.. wait what lock? We don't | |
4232 | * own any locks, you've been drinking again? | |
4233 | */ | |
dd471efe | 4234 | if (depth <= 0) { |
f7c1c6b3 YD |
4235 | print_unlock_imbalance_bug(curr, lock, ip); |
4236 | return 0; | |
4237 | } | |
fbb9ce95 | 4238 | |
e0f56fd7 PZ |
4239 | /* |
4240 | * Check whether the lock exists in the current stack | |
4241 | * of held locks: | |
4242 | */ | |
41c2c5b8 | 4243 | hlock = find_held_lock(curr, lock, depth, &i); |
f7c1c6b3 YD |
4244 | if (!hlock) { |
4245 | print_unlock_imbalance_bug(curr, lock, ip); | |
4246 | return 0; | |
4247 | } | |
fbb9ce95 | 4248 | |
bb97a91e PZ |
4249 | if (hlock->instance == lock) |
4250 | lock_release_holdtime(hlock); | |
4251 | ||
a24fc60d PZ |
4252 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
4253 | ||
bb97a91e PZ |
4254 | if (hlock->references) { |
4255 | hlock->references--; | |
4256 | if (hlock->references) { | |
4257 | /* | |
4258 | * We had, and after removing one, still have | |
4259 | * references, the current lock stack is still | |
4260 | * valid. We're done! | |
4261 | */ | |
4262 | return 1; | |
4263 | } | |
4264 | } | |
f20786ff | 4265 | |
fbb9ce95 IM |
4266 | /* |
4267 | * We have the right lock to unlock, 'hlock' points to it. | |
4268 | * Now we remove it from the stack, and add back the other | |
4269 | * entries (if any), recalculating the hash along the way: | |
4270 | */ | |
bb97a91e | 4271 | |
fbb9ce95 IM |
4272 | curr->lockdep_depth = i; |
4273 | curr->curr_chain_key = hlock->prev_chain_key; | |
4274 | ||
ce52a18d WL |
4275 | /* |
4276 | * The most likely case is when the unlock is on the innermost | |
4277 | * lock. In this case, we are done! | |
4278 | */ | |
4279 | if (i == depth-1) | |
4280 | return 1; | |
4281 | ||
8c8889d8 | 4282 | if (reacquire_held_locks(curr, depth, i + 1, &merged)) |
e969970b | 4283 | return 0; |
fbb9ce95 | 4284 | |
0119fee4 PZ |
4285 | /* |
4286 | * We had N bottles of beer on the wall, we drank one, but now | |
4287 | * there's not N-1 bottles of beer left on the wall... | |
8c8889d8 | 4288 | * Pouring two of the bottles together is acceptable. |
0119fee4 | 4289 | */ |
8c8889d8 | 4290 | DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged); |
f20786ff | 4291 | |
ce52a18d WL |
4292 | /* |
4293 | * Since reacquire_held_locks() would have called check_chain_key() | |
4294 | * indirectly via __lock_acquire(), we don't need to do it again | |
4295 | * on return. | |
4296 | */ | |
4297 | return 0; | |
fbb9ce95 IM |
4298 | } |
4299 | ||
2f43c602 MH |
4300 | static nokprobe_inline |
4301 | int __lock_is_held(const struct lockdep_map *lock, int read) | |
fbb9ce95 | 4302 | { |
f607c668 PZ |
4303 | struct task_struct *curr = current; |
4304 | int i; | |
fbb9ce95 | 4305 | |
f607c668 | 4306 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 4307 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 4308 | |
f8319483 PZ |
4309 | if (match_held_lock(hlock, lock)) { |
4310 | if (read == -1 || hlock->read == read) | |
4311 | return 1; | |
4312 | ||
4313 | return 0; | |
4314 | } | |
f607c668 | 4315 | } |
f20786ff | 4316 | |
f607c668 | 4317 | return 0; |
fbb9ce95 IM |
4318 | } |
4319 | ||
e7904a28 PZ |
4320 | static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) |
4321 | { | |
4322 | struct pin_cookie cookie = NIL_COOKIE; | |
4323 | struct task_struct *curr = current; | |
4324 | int i; | |
4325 | ||
4326 | if (unlikely(!debug_locks)) | |
4327 | return cookie; | |
4328 | ||
4329 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4330 | struct held_lock *hlock = curr->held_locks + i; | |
4331 | ||
4332 | if (match_held_lock(hlock, lock)) { | |
4333 | /* | |
4334 | * Grab 16bits of randomness; this is sufficient to not | |
4335 | * be guessable and still allows some pin nesting in | |
4336 | * our u32 pin_count. | |
4337 | */ | |
4338 | cookie.val = 1 + (prandom_u32() >> 16); | |
4339 | hlock->pin_count += cookie.val; | |
4340 | return cookie; | |
4341 | } | |
4342 | } | |
4343 | ||
4344 | WARN(1, "pinning an unheld lock\n"); | |
4345 | return cookie; | |
4346 | } | |
4347 | ||
4348 | static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
fbb9ce95 IM |
4349 | { |
4350 | struct task_struct *curr = current; | |
a24fc60d | 4351 | int i; |
fbb9ce95 | 4352 | |
a24fc60d | 4353 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
4354 | return; |
4355 | ||
a24fc60d PZ |
4356 | for (i = 0; i < curr->lockdep_depth; i++) { |
4357 | struct held_lock *hlock = curr->held_locks + i; | |
4358 | ||
4359 | if (match_held_lock(hlock, lock)) { | |
e7904a28 | 4360 | hlock->pin_count += cookie.val; |
fbb9ce95 | 4361 | return; |
a24fc60d | 4362 | } |
fbb9ce95 IM |
4363 | } |
4364 | ||
a24fc60d | 4365 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
4366 | } |
4367 | ||
e7904a28 | 4368 | static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
f607c668 PZ |
4369 | { |
4370 | struct task_struct *curr = current; | |
4371 | int i; | |
4372 | ||
a24fc60d PZ |
4373 | if (unlikely(!debug_locks)) |
4374 | return; | |
4375 | ||
f607c668 | 4376 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
4377 | struct held_lock *hlock = curr->held_locks + i; |
4378 | ||
a24fc60d PZ |
4379 | if (match_held_lock(hlock, lock)) { |
4380 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
4381 | return; | |
4382 | ||
e7904a28 PZ |
4383 | hlock->pin_count -= cookie.val; |
4384 | ||
4385 | if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n")) | |
4386 | hlock->pin_count = 0; | |
4387 | ||
a24fc60d PZ |
4388 | return; |
4389 | } | |
f607c668 PZ |
4390 | } |
4391 | ||
a24fc60d | 4392 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
4393 | } |
4394 | ||
fbb9ce95 IM |
4395 | /* |
4396 | * Check whether we follow the irq-flags state precisely: | |
4397 | */ | |
1d09daa5 | 4398 | static void check_flags(unsigned long flags) |
fbb9ce95 | 4399 | { |
30a35f79 | 4400 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) |
fbb9ce95 IM |
4401 | if (!debug_locks) |
4402 | return; | |
4403 | ||
5f9fa8a6 IM |
4404 | if (irqs_disabled_flags(flags)) { |
4405 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
4406 | printk("possible reason: unannotated irqs-off.\n"); | |
4407 | } | |
4408 | } else { | |
4409 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
4410 | printk("possible reason: unannotated irqs-on.\n"); | |
4411 | } | |
4412 | } | |
fbb9ce95 IM |
4413 | |
4414 | /* | |
4415 | * We dont accurately track softirq state in e.g. | |
4416 | * hardirq contexts (such as on 4KSTACKS), so only | |
4417 | * check if not in hardirq contexts: | |
4418 | */ | |
4419 | if (!hardirq_count()) { | |
0119fee4 PZ |
4420 | if (softirq_count()) { |
4421 | /* like the above, but with softirqs */ | |
fbb9ce95 | 4422 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
4423 | } else { |
4424 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 4425 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 4426 | } |
fbb9ce95 IM |
4427 | } |
4428 | ||
4429 | if (!debug_locks) | |
4430 | print_irqtrace_events(current); | |
4431 | #endif | |
4432 | } | |
4433 | ||
00ef9f73 PZ |
4434 | void lock_set_class(struct lockdep_map *lock, const char *name, |
4435 | struct lock_class_key *key, unsigned int subclass, | |
4436 | unsigned long ip) | |
64aa348e PZ |
4437 | { |
4438 | unsigned long flags; | |
4439 | ||
4440 | if (unlikely(current->lockdep_recursion)) | |
4441 | return; | |
4442 | ||
4443 | raw_local_irq_save(flags); | |
4444 | current->lockdep_recursion = 1; | |
4445 | check_flags(flags); | |
00ef9f73 | 4446 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
4447 | check_chain_key(current); |
4448 | current->lockdep_recursion = 0; | |
4449 | raw_local_irq_restore(flags); | |
4450 | } | |
00ef9f73 | 4451 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 4452 | |
6419c4af O |
4453 | void lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
4454 | { | |
4455 | unsigned long flags; | |
4456 | ||
4457 | if (unlikely(current->lockdep_recursion)) | |
4458 | return; | |
4459 | ||
4460 | raw_local_irq_save(flags); | |
4461 | current->lockdep_recursion = 1; | |
4462 | check_flags(flags); | |
4463 | if (__lock_downgrade(lock, ip)) | |
4464 | check_chain_key(current); | |
4465 | current->lockdep_recursion = 0; | |
4466 | raw_local_irq_restore(flags); | |
4467 | } | |
4468 | EXPORT_SYMBOL_GPL(lock_downgrade); | |
4469 | ||
fbb9ce95 IM |
4470 | /* |
4471 | * We are not always called with irqs disabled - do that here, | |
4472 | * and also avoid lockdep recursion: | |
4473 | */ | |
1d09daa5 | 4474 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
4475 | int trylock, int read, int check, |
4476 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
4477 | { |
4478 | unsigned long flags; | |
4479 | ||
4480 | if (unlikely(current->lockdep_recursion)) | |
4481 | return; | |
4482 | ||
4483 | raw_local_irq_save(flags); | |
4484 | check_flags(flags); | |
4485 | ||
4486 | current->lockdep_recursion = 1; | |
db2c4c77 | 4487 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 4488 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 4489 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
4490 | current->lockdep_recursion = 0; |
4491 | raw_local_irq_restore(flags); | |
4492 | } | |
fbb9ce95 IM |
4493 | EXPORT_SYMBOL_GPL(lock_acquire); |
4494 | ||
1d09daa5 | 4495 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 4496 | unsigned long ip) |
fbb9ce95 IM |
4497 | { |
4498 | unsigned long flags; | |
4499 | ||
4500 | if (unlikely(current->lockdep_recursion)) | |
4501 | return; | |
4502 | ||
4503 | raw_local_irq_save(flags); | |
4504 | check_flags(flags); | |
4505 | current->lockdep_recursion = 1; | |
93135439 | 4506 | trace_lock_release(lock, ip); |
b4adfe8e | 4507 | if (__lock_release(lock, ip)) |
e0f56fd7 | 4508 | check_chain_key(current); |
fbb9ce95 IM |
4509 | current->lockdep_recursion = 0; |
4510 | raw_local_irq_restore(flags); | |
4511 | } | |
fbb9ce95 IM |
4512 | EXPORT_SYMBOL_GPL(lock_release); |
4513 | ||
08f36ff6 | 4514 | int lock_is_held_type(const struct lockdep_map *lock, int read) |
f607c668 PZ |
4515 | { |
4516 | unsigned long flags; | |
4517 | int ret = 0; | |
4518 | ||
4519 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 4520 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
4521 | |
4522 | raw_local_irq_save(flags); | |
4523 | check_flags(flags); | |
4524 | ||
4525 | current->lockdep_recursion = 1; | |
f8319483 | 4526 | ret = __lock_is_held(lock, read); |
f607c668 PZ |
4527 | current->lockdep_recursion = 0; |
4528 | raw_local_irq_restore(flags); | |
4529 | ||
4530 | return ret; | |
4531 | } | |
f8319483 | 4532 | EXPORT_SYMBOL_GPL(lock_is_held_type); |
2f43c602 | 4533 | NOKPROBE_SYMBOL(lock_is_held_type); |
f607c668 | 4534 | |
e7904a28 | 4535 | struct pin_cookie lock_pin_lock(struct lockdep_map *lock) |
a24fc60d | 4536 | { |
e7904a28 | 4537 | struct pin_cookie cookie = NIL_COOKIE; |
a24fc60d PZ |
4538 | unsigned long flags; |
4539 | ||
4540 | if (unlikely(current->lockdep_recursion)) | |
e7904a28 | 4541 | return cookie; |
a24fc60d PZ |
4542 | |
4543 | raw_local_irq_save(flags); | |
4544 | check_flags(flags); | |
4545 | ||
4546 | current->lockdep_recursion = 1; | |
e7904a28 | 4547 | cookie = __lock_pin_lock(lock); |
a24fc60d PZ |
4548 | current->lockdep_recursion = 0; |
4549 | raw_local_irq_restore(flags); | |
e7904a28 PZ |
4550 | |
4551 | return cookie; | |
a24fc60d PZ |
4552 | } |
4553 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
4554 | ||
e7904a28 PZ |
4555 | void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
4556 | { | |
4557 | unsigned long flags; | |
4558 | ||
4559 | if (unlikely(current->lockdep_recursion)) | |
4560 | return; | |
4561 | ||
4562 | raw_local_irq_save(flags); | |
4563 | check_flags(flags); | |
4564 | ||
4565 | current->lockdep_recursion = 1; | |
4566 | __lock_repin_lock(lock, cookie); | |
4567 | current->lockdep_recursion = 0; | |
4568 | raw_local_irq_restore(flags); | |
4569 | } | |
4570 | EXPORT_SYMBOL_GPL(lock_repin_lock); | |
4571 | ||
4572 | void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
a24fc60d PZ |
4573 | { |
4574 | unsigned long flags; | |
4575 | ||
4576 | if (unlikely(current->lockdep_recursion)) | |
4577 | return; | |
4578 | ||
4579 | raw_local_irq_save(flags); | |
4580 | check_flags(flags); | |
4581 | ||
4582 | current->lockdep_recursion = 1; | |
e7904a28 | 4583 | __lock_unpin_lock(lock, cookie); |
a24fc60d PZ |
4584 | current->lockdep_recursion = 0; |
4585 | raw_local_irq_restore(flags); | |
4586 | } | |
4587 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
4588 | ||
f20786ff | 4589 | #ifdef CONFIG_LOCK_STAT |
f7c1c6b3 YD |
4590 | static void print_lock_contention_bug(struct task_struct *curr, |
4591 | struct lockdep_map *lock, | |
4592 | unsigned long ip) | |
f20786ff PZ |
4593 | { |
4594 | if (!debug_locks_off()) | |
f7c1c6b3 | 4595 | return; |
f20786ff | 4596 | if (debug_locks_silent) |
f7c1c6b3 | 4597 | return; |
f20786ff | 4598 | |
681fbec8 | 4599 | pr_warn("\n"); |
a5dd63ef PM |
4600 | pr_warn("=================================\n"); |
4601 | pr_warn("WARNING: bad contention detected!\n"); | |
fbdc4b9a | 4602 | print_kernel_ident(); |
a5dd63ef | 4603 | pr_warn("---------------------------------\n"); |
681fbec8 | 4604 | pr_warn("%s/%d is trying to contend lock (", |
ba25f9dc | 4605 | curr->comm, task_pid_nr(curr)); |
f20786ff | 4606 | print_lockdep_cache(lock); |
681fbec8 | 4607 | pr_cont(") at:\n"); |
f20786ff | 4608 | print_ip_sym(ip); |
681fbec8 PM |
4609 | pr_warn("but there are no locks held!\n"); |
4610 | pr_warn("\nother info that might help us debug this:\n"); | |
f20786ff PZ |
4611 | lockdep_print_held_locks(curr); |
4612 | ||
681fbec8 | 4613 | pr_warn("\nstack backtrace:\n"); |
f20786ff | 4614 | dump_stack(); |
f20786ff PZ |
4615 | } |
4616 | ||
4617 | static void | |
4618 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4619 | { | |
4620 | struct task_struct *curr = current; | |
41c2c5b8 | 4621 | struct held_lock *hlock; |
f20786ff PZ |
4622 | struct lock_class_stats *stats; |
4623 | unsigned int depth; | |
c7e78cff | 4624 | int i, contention_point, contending_point; |
f20786ff PZ |
4625 | |
4626 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4627 | /* |
4628 | * Whee, we contended on this lock, except it seems we're not | |
4629 | * actually trying to acquire anything much at all.. | |
4630 | */ | |
f20786ff PZ |
4631 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4632 | return; | |
4633 | ||
41c2c5b8 O |
4634 | hlock = find_held_lock(curr, lock, depth, &i); |
4635 | if (!hlock) { | |
4636 | print_lock_contention_bug(curr, lock, ip); | |
4637 | return; | |
f20786ff | 4638 | } |
f20786ff | 4639 | |
bb97a91e PZ |
4640 | if (hlock->instance != lock) |
4641 | return; | |
4642 | ||
3365e779 | 4643 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 4644 | |
c7e78cff PZ |
4645 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
4646 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
4647 | lock->ip); | |
f20786ff | 4648 | |
f82b217e | 4649 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
4650 | if (contention_point < LOCKSTAT_POINTS) |
4651 | stats->contention_point[contention_point]++; | |
4652 | if (contending_point < LOCKSTAT_POINTS) | |
4653 | stats->contending_point[contending_point]++; | |
96645678 PZ |
4654 | if (lock->cpu != smp_processor_id()) |
4655 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
4656 | } |
4657 | ||
4658 | static void | |
c7e78cff | 4659 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4660 | { |
4661 | struct task_struct *curr = current; | |
41c2c5b8 | 4662 | struct held_lock *hlock; |
f20786ff PZ |
4663 | struct lock_class_stats *stats; |
4664 | unsigned int depth; | |
3365e779 | 4665 | u64 now, waittime = 0; |
96645678 | 4666 | int i, cpu; |
f20786ff PZ |
4667 | |
4668 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4669 | /* |
4670 | * Yay, we acquired ownership of this lock we didn't try to | |
4671 | * acquire, how the heck did that happen? | |
4672 | */ | |
f20786ff PZ |
4673 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4674 | return; | |
4675 | ||
41c2c5b8 O |
4676 | hlock = find_held_lock(curr, lock, depth, &i); |
4677 | if (!hlock) { | |
4678 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
4679 | return; | |
f20786ff | 4680 | } |
f20786ff | 4681 | |
bb97a91e PZ |
4682 | if (hlock->instance != lock) |
4683 | return; | |
4684 | ||
96645678 PZ |
4685 | cpu = smp_processor_id(); |
4686 | if (hlock->waittime_stamp) { | |
3365e779 | 4687 | now = lockstat_clock(); |
96645678 PZ |
4688 | waittime = now - hlock->waittime_stamp; |
4689 | hlock->holdtime_stamp = now; | |
4690 | } | |
f20786ff | 4691 | |
883a2a31 | 4692 | trace_lock_acquired(lock, ip); |
2062501a | 4693 | |
f82b217e | 4694 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
4695 | if (waittime) { |
4696 | if (hlock->read) | |
4697 | lock_time_inc(&stats->read_waittime, waittime); | |
4698 | else | |
4699 | lock_time_inc(&stats->write_waittime, waittime); | |
4700 | } | |
4701 | if (lock->cpu != cpu) | |
4702 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
96645678 PZ |
4703 | |
4704 | lock->cpu = cpu; | |
c7e78cff | 4705 | lock->ip = ip; |
f20786ff PZ |
4706 | } |
4707 | ||
4708 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4709 | { | |
4710 | unsigned long flags; | |
4711 | ||
9506a742 | 4712 | if (unlikely(!lock_stat || !debug_locks)) |
f20786ff PZ |
4713 | return; |
4714 | ||
4715 | if (unlikely(current->lockdep_recursion)) | |
4716 | return; | |
4717 | ||
4718 | raw_local_irq_save(flags); | |
4719 | check_flags(flags); | |
4720 | current->lockdep_recursion = 1; | |
db2c4c77 | 4721 | trace_lock_contended(lock, ip); |
f20786ff PZ |
4722 | __lock_contended(lock, ip); |
4723 | current->lockdep_recursion = 0; | |
4724 | raw_local_irq_restore(flags); | |
4725 | } | |
4726 | EXPORT_SYMBOL_GPL(lock_contended); | |
4727 | ||
c7e78cff | 4728 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4729 | { |
4730 | unsigned long flags; | |
4731 | ||
9506a742 | 4732 | if (unlikely(!lock_stat || !debug_locks)) |
f20786ff PZ |
4733 | return; |
4734 | ||
4735 | if (unlikely(current->lockdep_recursion)) | |
4736 | return; | |
4737 | ||
4738 | raw_local_irq_save(flags); | |
4739 | check_flags(flags); | |
4740 | current->lockdep_recursion = 1; | |
c7e78cff | 4741 | __lock_acquired(lock, ip); |
f20786ff PZ |
4742 | current->lockdep_recursion = 0; |
4743 | raw_local_irq_restore(flags); | |
4744 | } | |
4745 | EXPORT_SYMBOL_GPL(lock_acquired); | |
4746 | #endif | |
4747 | ||
fbb9ce95 IM |
4748 | /* |
4749 | * Used by the testsuite, sanitize the validator state | |
4750 | * after a simulated failure: | |
4751 | */ | |
4752 | ||
4753 | void lockdep_reset(void) | |
4754 | { | |
4755 | unsigned long flags; | |
23d95a03 | 4756 | int i; |
fbb9ce95 IM |
4757 | |
4758 | raw_local_irq_save(flags); | |
e196e479 | 4759 | lockdep_init_task(current); |
fbb9ce95 IM |
4760 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); |
4761 | nr_hardirq_chains = 0; | |
4762 | nr_softirq_chains = 0; | |
4763 | nr_process_chains = 0; | |
4764 | debug_locks = 1; | |
23d95a03 | 4765 | for (i = 0; i < CHAINHASH_SIZE; i++) |
a63f38cc | 4766 | INIT_HLIST_HEAD(chainhash_table + i); |
fbb9ce95 IM |
4767 | raw_local_irq_restore(flags); |
4768 | } | |
4769 | ||
a0b0fd53 | 4770 | /* Remove a class from a lock chain. Must be called with the graph lock held. */ |
de4643a7 BVA |
4771 | static void remove_class_from_lock_chain(struct pending_free *pf, |
4772 | struct lock_chain *chain, | |
a0b0fd53 BVA |
4773 | struct lock_class *class) |
4774 | { | |
4775 | #ifdef CONFIG_PROVE_LOCKING | |
4776 | struct lock_chain *new_chain; | |
4777 | u64 chain_key; | |
4778 | int i; | |
4779 | ||
4780 | for (i = chain->base; i < chain->base + chain->depth; i++) { | |
4781 | if (chain_hlocks[i] != class - lock_classes) | |
4782 | continue; | |
4783 | /* The code below leaks one chain_hlock[] entry. */ | |
72dcd505 | 4784 | if (--chain->depth > 0) { |
a0b0fd53 BVA |
4785 | memmove(&chain_hlocks[i], &chain_hlocks[i + 1], |
4786 | (chain->base + chain->depth - i) * | |
4787 | sizeof(chain_hlocks[0])); | |
72dcd505 | 4788 | } |
a0b0fd53 BVA |
4789 | /* |
4790 | * Each lock class occurs at most once in a lock chain so once | |
4791 | * we found a match we can break out of this loop. | |
4792 | */ | |
4793 | goto recalc; | |
4794 | } | |
4795 | /* Since the chain has not been modified, return. */ | |
4796 | return; | |
4797 | ||
4798 | recalc: | |
f6ec8829 | 4799 | chain_key = INITIAL_CHAIN_KEY; |
a0b0fd53 | 4800 | for (i = chain->base; i < chain->base + chain->depth; i++) |
01bb6f0a | 4801 | chain_key = iterate_chain_key(chain_key, chain_hlocks[i]); |
a0b0fd53 BVA |
4802 | if (chain->depth && chain->chain_key == chain_key) |
4803 | return; | |
4804 | /* Overwrite the chain key for concurrent RCU readers. */ | |
4805 | WRITE_ONCE(chain->chain_key, chain_key); | |
4806 | /* | |
4807 | * Note: calling hlist_del_rcu() from inside a | |
4808 | * hlist_for_each_entry_rcu() loop is safe. | |
4809 | */ | |
4810 | hlist_del_rcu(&chain->entry); | |
de4643a7 | 4811 | __set_bit(chain - lock_chains, pf->lock_chains_being_freed); |
a0b0fd53 BVA |
4812 | if (chain->depth == 0) |
4813 | return; | |
4814 | /* | |
4815 | * If the modified lock chain matches an existing lock chain, drop | |
4816 | * the modified lock chain. | |
4817 | */ | |
4818 | if (lookup_chain_cache(chain_key)) | |
4819 | return; | |
de4643a7 BVA |
4820 | new_chain = alloc_lock_chain(); |
4821 | if (WARN_ON_ONCE(!new_chain)) { | |
a0b0fd53 BVA |
4822 | debug_locks_off(); |
4823 | return; | |
4824 | } | |
a0b0fd53 BVA |
4825 | *new_chain = *chain; |
4826 | hlist_add_head_rcu(&new_chain->entry, chainhashentry(chain_key)); | |
4827 | #endif | |
4828 | } | |
4829 | ||
4830 | /* Must be called with the graph lock held. */ | |
de4643a7 BVA |
4831 | static void remove_class_from_lock_chains(struct pending_free *pf, |
4832 | struct lock_class *class) | |
a0b0fd53 BVA |
4833 | { |
4834 | struct lock_chain *chain; | |
4835 | struct hlist_head *head; | |
4836 | int i; | |
4837 | ||
4838 | for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) { | |
4839 | head = chainhash_table + i; | |
4840 | hlist_for_each_entry_rcu(chain, head, entry) { | |
de4643a7 | 4841 | remove_class_from_lock_chain(pf, chain, class); |
a0b0fd53 BVA |
4842 | } |
4843 | } | |
4844 | } | |
4845 | ||
786fa29e BVA |
4846 | /* |
4847 | * Remove all references to a lock class. The caller must hold the graph lock. | |
4848 | */ | |
a0b0fd53 | 4849 | static void zap_class(struct pending_free *pf, struct lock_class *class) |
fbb9ce95 | 4850 | { |
86cffb80 | 4851 | struct lock_list *entry; |
fbb9ce95 IM |
4852 | int i; |
4853 | ||
a0b0fd53 BVA |
4854 | WARN_ON_ONCE(!class->key); |
4855 | ||
fbb9ce95 IM |
4856 | /* |
4857 | * Remove all dependencies this lock is | |
4858 | * involved in: | |
4859 | */ | |
ace35a7a BVA |
4860 | for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) { |
4861 | entry = list_entries + i; | |
86cffb80 BVA |
4862 | if (entry->class != class && entry->links_to != class) |
4863 | continue; | |
ace35a7a BVA |
4864 | __clear_bit(i, list_entries_in_use); |
4865 | nr_list_entries--; | |
86cffb80 | 4866 | list_del_rcu(&entry->entry); |
fbb9ce95 | 4867 | } |
a0b0fd53 BVA |
4868 | if (list_empty(&class->locks_after) && |
4869 | list_empty(&class->locks_before)) { | |
4870 | list_move_tail(&class->lock_entry, &pf->zapped); | |
4871 | hlist_del_rcu(&class->hash_entry); | |
4872 | WRITE_ONCE(class->key, NULL); | |
4873 | WRITE_ONCE(class->name, NULL); | |
4874 | nr_lock_classes--; | |
01bb6f0a | 4875 | __clear_bit(class - lock_classes, lock_classes_in_use); |
a0b0fd53 BVA |
4876 | } else { |
4877 | WARN_ONCE(true, "%s() failed for class %s\n", __func__, | |
4878 | class->name); | |
4879 | } | |
fbb9ce95 | 4880 | |
de4643a7 | 4881 | remove_class_from_lock_chains(pf, class); |
a0b0fd53 BVA |
4882 | } |
4883 | ||
4884 | static void reinit_class(struct lock_class *class) | |
4885 | { | |
4886 | void *const p = class; | |
4887 | const unsigned int offset = offsetof(struct lock_class, key); | |
4888 | ||
4889 | WARN_ON_ONCE(!class->lock_entry.next); | |
4890 | WARN_ON_ONCE(!list_empty(&class->locks_after)); | |
4891 | WARN_ON_ONCE(!list_empty(&class->locks_before)); | |
4892 | memset(p + offset, 0, sizeof(*class) - offset); | |
4893 | WARN_ON_ONCE(!class->lock_entry.next); | |
4894 | WARN_ON_ONCE(!list_empty(&class->locks_after)); | |
4895 | WARN_ON_ONCE(!list_empty(&class->locks_before)); | |
fbb9ce95 IM |
4896 | } |
4897 | ||
fabe874a | 4898 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
4899 | { |
4900 | return addr >= start && addr < start + size; | |
4901 | } | |
4902 | ||
a0b0fd53 BVA |
4903 | static bool inside_selftest(void) |
4904 | { | |
4905 | return current == lockdep_selftest_task_struct; | |
4906 | } | |
4907 | ||
4908 | /* The caller must hold the graph lock. */ | |
4909 | static struct pending_free *get_pending_free(void) | |
4910 | { | |
4911 | return delayed_free.pf + delayed_free.index; | |
4912 | } | |
4913 | ||
4914 | static void free_zapped_rcu(struct rcu_head *cb); | |
4915 | ||
4916 | /* | |
4917 | * Schedule an RCU callback if no RCU callback is pending. Must be called with | |
4918 | * the graph lock held. | |
4919 | */ | |
4920 | static void call_rcu_zapped(struct pending_free *pf) | |
4921 | { | |
4922 | WARN_ON_ONCE(inside_selftest()); | |
4923 | ||
4924 | if (list_empty(&pf->zapped)) | |
4925 | return; | |
4926 | ||
4927 | if (delayed_free.scheduled) | |
4928 | return; | |
4929 | ||
4930 | delayed_free.scheduled = true; | |
4931 | ||
4932 | WARN_ON_ONCE(delayed_free.pf + delayed_free.index != pf); | |
4933 | delayed_free.index ^= 1; | |
4934 | ||
4935 | call_rcu(&delayed_free.rcu_head, free_zapped_rcu); | |
4936 | } | |
4937 | ||
4938 | /* The caller must hold the graph lock. May be called from RCU context. */ | |
4939 | static void __free_zapped_classes(struct pending_free *pf) | |
4940 | { | |
4941 | struct lock_class *class; | |
4942 | ||
72dcd505 | 4943 | check_data_structures(); |
b526b2e3 | 4944 | |
a0b0fd53 BVA |
4945 | list_for_each_entry(class, &pf->zapped, lock_entry) |
4946 | reinit_class(class); | |
4947 | ||
4948 | list_splice_init(&pf->zapped, &free_lock_classes); | |
de4643a7 BVA |
4949 | |
4950 | #ifdef CONFIG_PROVE_LOCKING | |
4951 | bitmap_andnot(lock_chains_in_use, lock_chains_in_use, | |
4952 | pf->lock_chains_being_freed, ARRAY_SIZE(lock_chains)); | |
4953 | bitmap_clear(pf->lock_chains_being_freed, 0, ARRAY_SIZE(lock_chains)); | |
4954 | #endif | |
a0b0fd53 BVA |
4955 | } |
4956 | ||
4957 | static void free_zapped_rcu(struct rcu_head *ch) | |
4958 | { | |
4959 | struct pending_free *pf; | |
4960 | unsigned long flags; | |
4961 | ||
4962 | if (WARN_ON_ONCE(ch != &delayed_free.rcu_head)) | |
4963 | return; | |
4964 | ||
4965 | raw_local_irq_save(flags); | |
90c1cba2 BVA |
4966 | arch_spin_lock(&lockdep_lock); |
4967 | current->lockdep_recursion = 1; | |
a0b0fd53 BVA |
4968 | |
4969 | /* closed head */ | |
4970 | pf = delayed_free.pf + (delayed_free.index ^ 1); | |
4971 | __free_zapped_classes(pf); | |
4972 | delayed_free.scheduled = false; | |
4973 | ||
4974 | /* | |
4975 | * If there's anything on the open list, close and start a new callback. | |
4976 | */ | |
4977 | call_rcu_zapped(delayed_free.pf + delayed_free.index); | |
4978 | ||
90c1cba2 BVA |
4979 | current->lockdep_recursion = 0; |
4980 | arch_spin_unlock(&lockdep_lock); | |
a0b0fd53 BVA |
4981 | raw_local_irq_restore(flags); |
4982 | } | |
4983 | ||
4984 | /* | |
4985 | * Remove all lock classes from the class hash table and from the | |
4986 | * all_lock_classes list whose key or name is in the address range [start, | |
4987 | * start + size). Move these lock classes to the zapped_classes list. Must | |
4988 | * be called with the graph lock held. | |
4989 | */ | |
4990 | static void __lockdep_free_key_range(struct pending_free *pf, void *start, | |
4991 | unsigned long size) | |
956f3563 BVA |
4992 | { |
4993 | struct lock_class *class; | |
4994 | struct hlist_head *head; | |
4995 | int i; | |
4996 | ||
4997 | /* Unhash all classes that were created by a module. */ | |
4998 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
4999 | head = classhash_table + i; | |
5000 | hlist_for_each_entry_rcu(class, head, hash_entry) { | |
5001 | if (!within(class->key, start, size) && | |
5002 | !within(class->name, start, size)) | |
5003 | continue; | |
a0b0fd53 | 5004 | zap_class(pf, class); |
956f3563 BVA |
5005 | } |
5006 | } | |
5007 | } | |
5008 | ||
35a9393c PZ |
5009 | /* |
5010 | * Used in module.c to remove lock classes from memory that is going to be | |
5011 | * freed; and possibly re-used by other modules. | |
5012 | * | |
29fc33fb BVA |
5013 | * We will have had one synchronize_rcu() before getting here, so we're |
5014 | * guaranteed nobody will look up these exact classes -- they're properly dead | |
5015 | * but still allocated. | |
35a9393c | 5016 | */ |
a0b0fd53 | 5017 | static void lockdep_free_key_range_reg(void *start, unsigned long size) |
fbb9ce95 | 5018 | { |
a0b0fd53 | 5019 | struct pending_free *pf; |
fbb9ce95 | 5020 | unsigned long flags; |
fbb9ce95 | 5021 | |
feb0a386 BVA |
5022 | init_data_structures_once(); |
5023 | ||
fbb9ce95 | 5024 | raw_local_irq_save(flags); |
90c1cba2 BVA |
5025 | arch_spin_lock(&lockdep_lock); |
5026 | current->lockdep_recursion = 1; | |
a0b0fd53 BVA |
5027 | pf = get_pending_free(); |
5028 | __lockdep_free_key_range(pf, start, size); | |
5029 | call_rcu_zapped(pf); | |
90c1cba2 BVA |
5030 | current->lockdep_recursion = 0; |
5031 | arch_spin_unlock(&lockdep_lock); | |
fbb9ce95 | 5032 | raw_local_irq_restore(flags); |
35a9393c PZ |
5033 | |
5034 | /* | |
5035 | * Wait for any possible iterators from look_up_lock_class() to pass | |
5036 | * before continuing to free the memory they refer to. | |
35a9393c | 5037 | */ |
51959d85 | 5038 | synchronize_rcu(); |
a0b0fd53 | 5039 | } |
35a9393c | 5040 | |
a0b0fd53 BVA |
5041 | /* |
5042 | * Free all lockdep keys in the range [start, start+size). Does not sleep. | |
5043 | * Ignores debug_locks. Must only be used by the lockdep selftests. | |
5044 | */ | |
5045 | static void lockdep_free_key_range_imm(void *start, unsigned long size) | |
5046 | { | |
5047 | struct pending_free *pf = delayed_free.pf; | |
5048 | unsigned long flags; | |
5049 | ||
5050 | init_data_structures_once(); | |
5051 | ||
5052 | raw_local_irq_save(flags); | |
5053 | arch_spin_lock(&lockdep_lock); | |
5054 | __lockdep_free_key_range(pf, start, size); | |
5055 | __free_zapped_classes(pf); | |
5056 | arch_spin_unlock(&lockdep_lock); | |
5057 | raw_local_irq_restore(flags); | |
5058 | } | |
5059 | ||
5060 | void lockdep_free_key_range(void *start, unsigned long size) | |
5061 | { | |
5062 | init_data_structures_once(); | |
5063 | ||
5064 | if (inside_selftest()) | |
5065 | lockdep_free_key_range_imm(start, size); | |
5066 | else | |
5067 | lockdep_free_key_range_reg(start, size); | |
fbb9ce95 IM |
5068 | } |
5069 | ||
2904d9fa BVA |
5070 | /* |
5071 | * Check whether any element of the @lock->class_cache[] array refers to a | |
5072 | * registered lock class. The caller must hold either the graph lock or the | |
5073 | * RCU read lock. | |
5074 | */ | |
5075 | static bool lock_class_cache_is_registered(struct lockdep_map *lock) | |
fbb9ce95 | 5076 | { |
35a9393c | 5077 | struct lock_class *class; |
a63f38cc | 5078 | struct hlist_head *head; |
fbb9ce95 | 5079 | int i, j; |
2904d9fa BVA |
5080 | |
5081 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
5082 | head = classhash_table + i; | |
5083 | hlist_for_each_entry_rcu(class, head, hash_entry) { | |
5084 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
5085 | if (lock->class_cache[j] == class) | |
5086 | return true; | |
5087 | } | |
5088 | } | |
5089 | return false; | |
5090 | } | |
5091 | ||
956f3563 | 5092 | /* The caller must hold the graph lock. Does not sleep. */ |
a0b0fd53 BVA |
5093 | static void __lockdep_reset_lock(struct pending_free *pf, |
5094 | struct lockdep_map *lock) | |
2904d9fa BVA |
5095 | { |
5096 | struct lock_class *class; | |
956f3563 | 5097 | int j; |
fbb9ce95 IM |
5098 | |
5099 | /* | |
d6d897ce IM |
5100 | * Remove all classes this lock might have: |
5101 | */ | |
5102 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
5103 | /* | |
5104 | * If the class exists we look it up and zap it: | |
5105 | */ | |
5106 | class = look_up_lock_class(lock, j); | |
64f29d1b | 5107 | if (class) |
a0b0fd53 | 5108 | zap_class(pf, class); |
d6d897ce IM |
5109 | } |
5110 | /* | |
5111 | * Debug check: in the end all mapped classes should | |
5112 | * be gone. | |
fbb9ce95 | 5113 | */ |
956f3563 BVA |
5114 | if (WARN_ON_ONCE(lock_class_cache_is_registered(lock))) |
5115 | debug_locks_off(); | |
5116 | } | |
5117 | ||
a0b0fd53 BVA |
5118 | /* |
5119 | * Remove all information lockdep has about a lock if debug_locks == 1. Free | |
5120 | * released data structures from RCU context. | |
5121 | */ | |
5122 | static void lockdep_reset_lock_reg(struct lockdep_map *lock) | |
956f3563 | 5123 | { |
a0b0fd53 | 5124 | struct pending_free *pf; |
956f3563 BVA |
5125 | unsigned long flags; |
5126 | int locked; | |
5127 | ||
956f3563 BVA |
5128 | raw_local_irq_save(flags); |
5129 | locked = graph_lock(); | |
a0b0fd53 BVA |
5130 | if (!locked) |
5131 | goto out_irq; | |
5132 | ||
5133 | pf = get_pending_free(); | |
5134 | __lockdep_reset_lock(pf, lock); | |
5135 | call_rcu_zapped(pf); | |
5136 | ||
5137 | graph_unlock(); | |
5138 | out_irq: | |
5139 | raw_local_irq_restore(flags); | |
5140 | } | |
5141 | ||
5142 | /* | |
5143 | * Reset a lock. Does not sleep. Ignores debug_locks. Must only be used by the | |
5144 | * lockdep selftests. | |
5145 | */ | |
5146 | static void lockdep_reset_lock_imm(struct lockdep_map *lock) | |
5147 | { | |
5148 | struct pending_free *pf = delayed_free.pf; | |
5149 | unsigned long flags; | |
5150 | ||
5151 | raw_local_irq_save(flags); | |
5152 | arch_spin_lock(&lockdep_lock); | |
5153 | __lockdep_reset_lock(pf, lock); | |
5154 | __free_zapped_classes(pf); | |
5155 | arch_spin_unlock(&lockdep_lock); | |
fbb9ce95 IM |
5156 | raw_local_irq_restore(flags); |
5157 | } | |
5158 | ||
a0b0fd53 BVA |
5159 | void lockdep_reset_lock(struct lockdep_map *lock) |
5160 | { | |
5161 | init_data_structures_once(); | |
5162 | ||
5163 | if (inside_selftest()) | |
5164 | lockdep_reset_lock_imm(lock); | |
5165 | else | |
5166 | lockdep_reset_lock_reg(lock); | |
5167 | } | |
5168 | ||
108c1485 BVA |
5169 | /* Unregister a dynamically allocated key. */ |
5170 | void lockdep_unregister_key(struct lock_class_key *key) | |
5171 | { | |
5172 | struct hlist_head *hash_head = keyhashentry(key); | |
5173 | struct lock_class_key *k; | |
5174 | struct pending_free *pf; | |
5175 | unsigned long flags; | |
5176 | bool found = false; | |
5177 | ||
5178 | might_sleep(); | |
5179 | ||
5180 | if (WARN_ON_ONCE(static_obj(key))) | |
5181 | return; | |
5182 | ||
5183 | raw_local_irq_save(flags); | |
8b39adbe BVA |
5184 | if (!graph_lock()) |
5185 | goto out_irq; | |
5186 | ||
108c1485 BVA |
5187 | pf = get_pending_free(); |
5188 | hlist_for_each_entry_rcu(k, hash_head, hash_entry) { | |
5189 | if (k == key) { | |
5190 | hlist_del_rcu(&k->hash_entry); | |
5191 | found = true; | |
5192 | break; | |
5193 | } | |
5194 | } | |
5195 | WARN_ON_ONCE(!found); | |
5196 | __lockdep_free_key_range(pf, key, 1); | |
5197 | call_rcu_zapped(pf); | |
8b39adbe BVA |
5198 | graph_unlock(); |
5199 | out_irq: | |
108c1485 BVA |
5200 | raw_local_irq_restore(flags); |
5201 | ||
5202 | /* Wait until is_dynamic_key() has finished accessing k->hash_entry. */ | |
5203 | synchronize_rcu(); | |
5204 | } | |
5205 | EXPORT_SYMBOL_GPL(lockdep_unregister_key); | |
5206 | ||
c3bc8fd6 | 5207 | void __init lockdep_init(void) |
fbb9ce95 IM |
5208 | { |
5209 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
5210 | ||
b0788caf | 5211 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
5212 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
5213 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 5214 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
5215 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
5216 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
5217 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
5218 | ||
09d75ecb | 5219 | printk(" memory used by lock dependency info: %zu kB\n", |
7ff8517e | 5220 | (sizeof(lock_classes) + |
01bb6f0a | 5221 | sizeof(lock_classes_in_use) + |
7ff8517e BVA |
5222 | sizeof(classhash_table) + |
5223 | sizeof(list_entries) + | |
ace35a7a | 5224 | sizeof(list_entries_in_use) + |
a0b0fd53 BVA |
5225 | sizeof(chainhash_table) + |
5226 | sizeof(delayed_free) | |
4dd861d6 | 5227 | #ifdef CONFIG_PROVE_LOCKING |
7ff8517e | 5228 | + sizeof(lock_cq) |
15ea86b5 | 5229 | + sizeof(lock_chains) |
de4643a7 | 5230 | + sizeof(lock_chains_in_use) |
15ea86b5 | 5231 | + sizeof(chain_hlocks) |
4dd861d6 | 5232 | #endif |
90629209 | 5233 | ) / 1024 |
4dd861d6 | 5234 | ); |
fbb9ce95 | 5235 | |
12593b74 BVA |
5236 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
5237 | printk(" memory used for stack traces: %zu kB\n", | |
5238 | (sizeof(stack_trace) + sizeof(stack_trace_hash)) / 1024 | |
5239 | ); | |
5240 | #endif | |
5241 | ||
09d75ecb | 5242 | printk(" per task-struct memory footprint: %zu bytes\n", |
7ff8517e | 5243 | sizeof(((struct task_struct *)NULL)->held_locks)); |
fbb9ce95 IM |
5244 | } |
5245 | ||
fbb9ce95 IM |
5246 | static void |
5247 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 5248 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
5249 | { |
5250 | if (!debug_locks_off()) | |
5251 | return; | |
5252 | if (debug_locks_silent) | |
5253 | return; | |
5254 | ||
681fbec8 | 5255 | pr_warn("\n"); |
a5dd63ef PM |
5256 | pr_warn("=========================\n"); |
5257 | pr_warn("WARNING: held lock freed!\n"); | |
fbdc4b9a | 5258 | print_kernel_ident(); |
a5dd63ef | 5259 | pr_warn("-------------------------\n"); |
04860d48 | 5260 | pr_warn("%s/%d is freeing memory %px-%px, with a lock still held there!\n", |
ba25f9dc | 5261 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 5262 | print_lock(hlock); |
fbb9ce95 IM |
5263 | lockdep_print_held_locks(curr); |
5264 | ||
681fbec8 | 5265 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
5266 | dump_stack(); |
5267 | } | |
5268 | ||
54561783 ON |
5269 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
5270 | const void* lock_from, unsigned long lock_len) | |
5271 | { | |
5272 | return lock_from + lock_len <= mem_from || | |
5273 | mem_from + mem_len <= lock_from; | |
5274 | } | |
5275 | ||
fbb9ce95 IM |
5276 | /* |
5277 | * Called when kernel memory is freed (or unmapped), or if a lock | |
5278 | * is destroyed or reinitialized - this code checks whether there is | |
5279 | * any held lock in the memory range of <from> to <to>: | |
5280 | */ | |
5281 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
5282 | { | |
fbb9ce95 IM |
5283 | struct task_struct *curr = current; |
5284 | struct held_lock *hlock; | |
5285 | unsigned long flags; | |
5286 | int i; | |
5287 | ||
5288 | if (unlikely(!debug_locks)) | |
5289 | return; | |
5290 | ||
fcc784be | 5291 | raw_local_irq_save(flags); |
fbb9ce95 IM |
5292 | for (i = 0; i < curr->lockdep_depth; i++) { |
5293 | hlock = curr->held_locks + i; | |
5294 | ||
54561783 ON |
5295 | if (not_in_range(mem_from, mem_len, hlock->instance, |
5296 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
5297 | continue; |
5298 | ||
54561783 | 5299 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
5300 | break; |
5301 | } | |
fcc784be | 5302 | raw_local_irq_restore(flags); |
fbb9ce95 | 5303 | } |
ed07536e | 5304 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 5305 | |
1b1d2fb4 | 5306 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
5307 | { |
5308 | if (!debug_locks_off()) | |
5309 | return; | |
5310 | if (debug_locks_silent) | |
5311 | return; | |
5312 | ||
681fbec8 | 5313 | pr_warn("\n"); |
a5dd63ef PM |
5314 | pr_warn("====================================\n"); |
5315 | pr_warn("WARNING: %s/%d still has locks held!\n", | |
1b1d2fb4 | 5316 | current->comm, task_pid_nr(current)); |
fbdc4b9a | 5317 | print_kernel_ident(); |
a5dd63ef | 5318 | pr_warn("------------------------------------\n"); |
1b1d2fb4 | 5319 | lockdep_print_held_locks(current); |
681fbec8 | 5320 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
5321 | dump_stack(); |
5322 | } | |
5323 | ||
1b1d2fb4 | 5324 | void debug_check_no_locks_held(void) |
fbb9ce95 | 5325 | { |
1b1d2fb4 CC |
5326 | if (unlikely(current->lockdep_depth > 0)) |
5327 | print_held_locks_bug(); | |
fbb9ce95 | 5328 | } |
1b1d2fb4 | 5329 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 5330 | |
8dce7a9a | 5331 | #ifdef __KERNEL__ |
fbb9ce95 IM |
5332 | void debug_show_all_locks(void) |
5333 | { | |
5334 | struct task_struct *g, *p; | |
fbb9ce95 | 5335 | |
9c35dd7f | 5336 | if (unlikely(!debug_locks)) { |
681fbec8 | 5337 | pr_warn("INFO: lockdep is turned off.\n"); |
9c35dd7f JP |
5338 | return; |
5339 | } | |
681fbec8 | 5340 | pr_warn("\nShowing all locks held in the system:\n"); |
fbb9ce95 | 5341 | |
0f736a52 TH |
5342 | rcu_read_lock(); |
5343 | for_each_process_thread(g, p) { | |
0f736a52 TH |
5344 | if (!p->lockdep_depth) |
5345 | continue; | |
5346 | lockdep_print_held_locks(p); | |
88f1c87d | 5347 | touch_nmi_watchdog(); |
0f736a52 TH |
5348 | touch_all_softlockup_watchdogs(); |
5349 | } | |
5350 | rcu_read_unlock(); | |
fbb9ce95 | 5351 | |
681fbec8 | 5352 | pr_warn("\n"); |
a5dd63ef | 5353 | pr_warn("=============================================\n\n"); |
fbb9ce95 | 5354 | } |
fbb9ce95 | 5355 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 5356 | #endif |
fbb9ce95 | 5357 | |
82a1fcb9 IM |
5358 | /* |
5359 | * Careful: only use this function if you are sure that | |
5360 | * the task cannot run in parallel! | |
5361 | */ | |
f1b499f0 | 5362 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 5363 | { |
9c35dd7f JP |
5364 | if (unlikely(!debug_locks)) { |
5365 | printk("INFO: lockdep is turned off.\n"); | |
5366 | return; | |
5367 | } | |
fbb9ce95 IM |
5368 | lockdep_print_held_locks(task); |
5369 | } | |
fbb9ce95 | 5370 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 5371 | |
722a9f92 | 5372 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
5373 | { |
5374 | struct task_struct *curr = current; | |
5375 | ||
5376 | if (unlikely(curr->lockdep_depth)) { | |
5377 | if (!debug_locks_off()) | |
5378 | return; | |
681fbec8 | 5379 | pr_warn("\n"); |
a5dd63ef PM |
5380 | pr_warn("================================================\n"); |
5381 | pr_warn("WARNING: lock held when returning to user space!\n"); | |
fbdc4b9a | 5382 | print_kernel_ident(); |
a5dd63ef | 5383 | pr_warn("------------------------------------------------\n"); |
681fbec8 | 5384 | pr_warn("%s/%d is leaving the kernel with locks still held!\n", |
b351d164 PZ |
5385 | curr->comm, curr->pid); |
5386 | lockdep_print_held_locks(curr); | |
5387 | } | |
b09be676 BP |
5388 | |
5389 | /* | |
5390 | * The lock history for each syscall should be independent. So wipe the | |
5391 | * slate clean on return to userspace. | |
5392 | */ | |
f52be570 | 5393 | lockdep_invariant_state(false); |
b351d164 | 5394 | } |
0632eb3d | 5395 | |
b3fbab05 | 5396 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
5397 | { |
5398 | struct task_struct *curr = current; | |
5399 | ||
2b3fc35f | 5400 | /* Note: the following can be executed concurrently, so be careful. */ |
681fbec8 | 5401 | pr_warn("\n"); |
a5dd63ef PM |
5402 | pr_warn("=============================\n"); |
5403 | pr_warn("WARNING: suspicious RCU usage\n"); | |
fbdc4b9a | 5404 | print_kernel_ident(); |
a5dd63ef | 5405 | pr_warn("-----------------------------\n"); |
681fbec8 PM |
5406 | pr_warn("%s:%d %s!\n", file, line, s); |
5407 | pr_warn("\nother info that might help us debug this:\n\n"); | |
5408 | pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n", | |
c5fdcec9 PM |
5409 | !rcu_lockdep_current_cpu_online() |
5410 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 5411 | : !rcu_is_watching() |
c5fdcec9 PM |
5412 | ? "RCU used illegally from idle CPU!\n" |
5413 | : "", | |
5414 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
5415 | |
5416 | /* | |
5417 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
5418 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
5419 | * considers that CPU to be in an "extended quiescent state", | |
5420 | * which means that RCU will be completely ignoring that CPU. | |
5421 | * Therefore, rcu_read_lock() and friends have absolutely no | |
5422 | * effect on a CPU running in that state. In other words, even if | |
5423 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
5424 | * delete data structures out from under it. RCU really has no | |
5425 | * choice here: we need to keep an RCU-free window in idle where | |
5426 | * the CPU may possibly enter into low power mode. This way we can | |
5427 | * notice an extended quiescent state to other CPUs that started a grace | |
5428 | * period. Otherwise we would delay any grace period as long as we run | |
5429 | * in the idle task. | |
5430 | * | |
5431 | * So complain bitterly if someone does call rcu_read_lock(), | |
5432 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
5433 | */ | |
5c173eb8 | 5434 | if (!rcu_is_watching()) |
681fbec8 | 5435 | pr_warn("RCU used illegally from extended quiescent state!\n"); |
0464e937 | 5436 | |
0632eb3d | 5437 | lockdep_print_held_locks(curr); |
681fbec8 | 5438 | pr_warn("\nstack backtrace:\n"); |
0632eb3d PM |
5439 | dump_stack(); |
5440 | } | |
b3fbab05 | 5441 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |