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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]; |
fbb9ce95 | 154 | |
f82b217e DJ |
155 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
156 | { | |
157 | if (!hlock->class_idx) { | |
0119fee4 PZ |
158 | /* |
159 | * Someone passed in garbage, we give up. | |
160 | */ | |
f82b217e DJ |
161 | DEBUG_LOCKS_WARN_ON(1); |
162 | return NULL; | |
163 | } | |
164 | return lock_classes + hlock->class_idx - 1; | |
165 | } | |
166 | ||
f20786ff | 167 | #ifdef CONFIG_LOCK_STAT |
25528213 | 168 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
f20786ff | 169 | |
3365e779 PZ |
170 | static inline u64 lockstat_clock(void) |
171 | { | |
c676329a | 172 | return local_clock(); |
3365e779 PZ |
173 | } |
174 | ||
c7e78cff | 175 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
176 | { |
177 | int i; | |
178 | ||
c7e78cff PZ |
179 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
180 | if (points[i] == 0) { | |
181 | points[i] = ip; | |
f20786ff PZ |
182 | break; |
183 | } | |
c7e78cff | 184 | if (points[i] == ip) |
f20786ff PZ |
185 | break; |
186 | } | |
187 | ||
188 | return i; | |
189 | } | |
190 | ||
3365e779 | 191 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
192 | { |
193 | if (time > lt->max) | |
194 | lt->max = time; | |
195 | ||
109d71c6 | 196 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
197 | lt->min = time; |
198 | ||
199 | lt->total += time; | |
200 | lt->nr++; | |
201 | } | |
202 | ||
c46261de PZ |
203 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
204 | { | |
109d71c6 FR |
205 | if (!src->nr) |
206 | return; | |
207 | ||
208 | if (src->max > dst->max) | |
209 | dst->max = src->max; | |
210 | ||
211 | if (src->min < dst->min || !dst->nr) | |
212 | dst->min = src->min; | |
213 | ||
c46261de PZ |
214 | dst->total += src->total; |
215 | dst->nr += src->nr; | |
216 | } | |
217 | ||
218 | struct lock_class_stats lock_stats(struct lock_class *class) | |
219 | { | |
220 | struct lock_class_stats stats; | |
221 | int cpu, i; | |
222 | ||
223 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
224 | for_each_possible_cpu(cpu) { | |
225 | struct lock_class_stats *pcs = | |
1871e52c | 226 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
227 | |
228 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
229 | stats.contention_point[i] += pcs->contention_point[i]; | |
230 | ||
c7e78cff PZ |
231 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
232 | stats.contending_point[i] += pcs->contending_point[i]; | |
233 | ||
c46261de PZ |
234 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
235 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
236 | ||
237 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
238 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
239 | |
240 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
241 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
242 | } |
243 | ||
244 | return stats; | |
245 | } | |
246 | ||
247 | void clear_lock_stats(struct lock_class *class) | |
248 | { | |
249 | int cpu; | |
250 | ||
251 | for_each_possible_cpu(cpu) { | |
252 | struct lock_class_stats *cpu_stats = | |
1871e52c | 253 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
254 | |
255 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
256 | } | |
257 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 258 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
259 | } |
260 | ||
f20786ff PZ |
261 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
262 | { | |
01f38497 | 263 | return &this_cpu_ptr(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
264 | } |
265 | ||
266 | static void lock_release_holdtime(struct held_lock *hlock) | |
267 | { | |
268 | struct lock_class_stats *stats; | |
3365e779 | 269 | u64 holdtime; |
f20786ff PZ |
270 | |
271 | if (!lock_stat) | |
272 | return; | |
273 | ||
3365e779 | 274 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 275 | |
f82b217e | 276 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
277 | if (hlock->read) |
278 | lock_time_inc(&stats->read_holdtime, holdtime); | |
279 | else | |
280 | lock_time_inc(&stats->write_holdtime, holdtime); | |
f20786ff PZ |
281 | } |
282 | #else | |
283 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
284 | { | |
285 | } | |
286 | #endif | |
287 | ||
fbb9ce95 | 288 | /* |
a0b0fd53 BVA |
289 | * We keep a global list of all lock classes. The list is only accessed with |
290 | * the lockdep spinlock lock held. free_lock_classes is a list with free | |
291 | * elements. These elements are linked together by the lock_entry member in | |
292 | * struct lock_class. | |
fbb9ce95 IM |
293 | */ |
294 | LIST_HEAD(all_lock_classes); | |
a0b0fd53 BVA |
295 | static LIST_HEAD(free_lock_classes); |
296 | ||
297 | /** | |
298 | * struct pending_free - information about data structures about to be freed | |
299 | * @zapped: Head of a list with struct lock_class elements. | |
de4643a7 BVA |
300 | * @lock_chains_being_freed: Bitmap that indicates which lock_chains[] elements |
301 | * are about to be freed. | |
a0b0fd53 BVA |
302 | */ |
303 | struct pending_free { | |
304 | struct list_head zapped; | |
de4643a7 | 305 | DECLARE_BITMAP(lock_chains_being_freed, MAX_LOCKDEP_CHAINS); |
a0b0fd53 BVA |
306 | }; |
307 | ||
308 | /** | |
309 | * struct delayed_free - data structures used for delayed freeing | |
310 | * | |
311 | * A data structure for delayed freeing of data structures that may be | |
312 | * accessed by RCU readers at the time these were freed. | |
313 | * | |
314 | * @rcu_head: Used to schedule an RCU callback for freeing data structures. | |
315 | * @index: Index of @pf to which freed data structures are added. | |
316 | * @scheduled: Whether or not an RCU callback has been scheduled. | |
317 | * @pf: Array with information about data structures about to be freed. | |
318 | */ | |
319 | static struct delayed_free { | |
320 | struct rcu_head rcu_head; | |
321 | int index; | |
322 | int scheduled; | |
323 | struct pending_free pf[2]; | |
324 | } delayed_free; | |
fbb9ce95 IM |
325 | |
326 | /* | |
327 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
328 | */ | |
329 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
330 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 331 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
332 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
333 | ||
a63f38cc | 334 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
fbb9ce95 | 335 | |
fbb9ce95 IM |
336 | /* |
337 | * We put the lock dependency chains into a hash-table as well, to cache | |
338 | * their existence: | |
339 | */ | |
340 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
341 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 342 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
343 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
344 | ||
a63f38cc | 345 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
fbb9ce95 IM |
346 | |
347 | /* | |
348 | * The hash key of the lock dependency chains is a hash itself too: | |
349 | * it's a hash of all locks taken up to that lock, including that lock. | |
350 | * It's a 64-bit hash, because it's important for the keys to be | |
351 | * unique. | |
352 | */ | |
dfaaf3fa PZ |
353 | static inline u64 iterate_chain_key(u64 key, u32 idx) |
354 | { | |
355 | u32 k0 = key, k1 = key >> 32; | |
356 | ||
357 | __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ | |
358 | ||
359 | return k0 | (u64)k1 << 32; | |
360 | } | |
fbb9ce95 | 361 | |
1d09daa5 | 362 | void lockdep_off(void) |
fbb9ce95 IM |
363 | { |
364 | current->lockdep_recursion++; | |
365 | } | |
fbb9ce95 IM |
366 | EXPORT_SYMBOL(lockdep_off); |
367 | ||
1d09daa5 | 368 | void lockdep_on(void) |
fbb9ce95 IM |
369 | { |
370 | current->lockdep_recursion--; | |
371 | } | |
fbb9ce95 IM |
372 | EXPORT_SYMBOL(lockdep_on); |
373 | ||
cdc84d79 BVA |
374 | void lockdep_set_selftest_task(struct task_struct *task) |
375 | { | |
376 | lockdep_selftest_task_struct = task; | |
377 | } | |
378 | ||
fbb9ce95 IM |
379 | /* |
380 | * Debugging switches: | |
381 | */ | |
382 | ||
383 | #define VERBOSE 0 | |
33e94e96 | 384 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
385 | |
386 | #if VERBOSE | |
387 | # define HARDIRQ_VERBOSE 1 | |
388 | # define SOFTIRQ_VERBOSE 1 | |
389 | #else | |
390 | # define HARDIRQ_VERBOSE 0 | |
391 | # define SOFTIRQ_VERBOSE 0 | |
392 | #endif | |
393 | ||
d92a8cfc | 394 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE |
fbb9ce95 IM |
395 | /* |
396 | * Quick filtering for interesting events: | |
397 | */ | |
398 | static int class_filter(struct lock_class *class) | |
399 | { | |
f9829cce AK |
400 | #if 0 |
401 | /* Example */ | |
fbb9ce95 | 402 | if (class->name_version == 1 && |
f9829cce | 403 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
404 | return 1; |
405 | if (class->name_version == 1 && | |
f9829cce | 406 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 407 | return 1; |
f9829cce | 408 | #endif |
a6640897 IM |
409 | /* Filter everything else. 1 would be to allow everything else */ |
410 | return 0; | |
fbb9ce95 IM |
411 | } |
412 | #endif | |
413 | ||
414 | static int verbose(struct lock_class *class) | |
415 | { | |
416 | #if VERBOSE | |
417 | return class_filter(class); | |
418 | #endif | |
419 | return 0; | |
420 | } | |
421 | ||
fbb9ce95 IM |
422 | /* |
423 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 424 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
425 | */ |
426 | unsigned long nr_stack_trace_entries; | |
427 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
428 | ||
2c522836 DJ |
429 | static void print_lockdep_off(const char *bug_msg) |
430 | { | |
431 | printk(KERN_DEBUG "%s\n", bug_msg); | |
432 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 433 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 434 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 435 | #endif |
2c522836 DJ |
436 | } |
437 | ||
c120bce7 | 438 | static int save_trace(struct lock_trace *trace) |
fbb9ce95 | 439 | { |
c120bce7 TG |
440 | unsigned long *entries = stack_trace + nr_stack_trace_entries; |
441 | unsigned int max_entries; | |
fbb9ce95 | 442 | |
c120bce7 TG |
443 | trace->offset = nr_stack_trace_entries; |
444 | max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
445 | trace->nr_entries = stack_trace_save(entries, max_entries, 3); | |
fbb9ce95 | 446 | nr_stack_trace_entries += trace->nr_entries; |
fbb9ce95 | 447 | |
4f84f433 | 448 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
449 | if (!debug_locks_off_graph_unlock()) |
450 | return 0; | |
451 | ||
2c522836 | 452 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
453 | dump_stack(); |
454 | ||
fbb9ce95 IM |
455 | return 0; |
456 | } | |
457 | ||
458 | return 1; | |
459 | } | |
460 | ||
461 | unsigned int nr_hardirq_chains; | |
462 | unsigned int nr_softirq_chains; | |
463 | unsigned int nr_process_chains; | |
464 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
465 | |
466 | #ifdef CONFIG_DEBUG_LOCKDEP | |
fbb9ce95 IM |
467 | /* |
468 | * Various lockdep statistics: | |
469 | */ | |
bd6d29c2 | 470 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
471 | #endif |
472 | ||
473 | /* | |
474 | * Locking printouts: | |
475 | */ | |
476 | ||
fabe9c42 | 477 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
478 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
479 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
480 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
481 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 482 | |
fbb9ce95 IM |
483 | static const char *usage_str[] = |
484 | { | |
fabe9c42 PZ |
485 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
486 | #include "lockdep_states.h" | |
487 | #undef LOCKDEP_STATE | |
488 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
489 | }; |
490 | ||
491 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
492 | { | |
ffb45122 | 493 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
494 | } |
495 | ||
3ff176ca | 496 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 497 | { |
3ff176ca PZ |
498 | return 1UL << bit; |
499 | } | |
fbb9ce95 | 500 | |
3ff176ca PZ |
501 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
502 | { | |
503 | char c = '.'; | |
504 | ||
c902a1e8 | 505 | if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) |
3ff176ca PZ |
506 | c = '+'; |
507 | if (class->usage_mask & lock_flag(bit)) { | |
508 | c = '-'; | |
c902a1e8 | 509 | if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) |
3ff176ca | 510 | c = '?'; |
fbb9ce95 IM |
511 | } |
512 | ||
3ff176ca PZ |
513 | return c; |
514 | } | |
cf40bd16 | 515 | |
f510b233 | 516 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 517 | { |
f510b233 | 518 | int i = 0; |
cf40bd16 | 519 | |
f510b233 PZ |
520 | #define LOCKDEP_STATE(__STATE) \ |
521 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
522 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
523 | #include "lockdep_states.h" | |
524 | #undef LOCKDEP_STATE | |
525 | ||
526 | usage[i] = '\0'; | |
fbb9ce95 IM |
527 | } |
528 | ||
e5e78d08 | 529 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
530 | { |
531 | char str[KSYM_NAME_LEN]; | |
532 | const char *name; | |
533 | ||
fbb9ce95 IM |
534 | name = class->name; |
535 | if (!name) { | |
536 | name = __get_key_name(class->key, str); | |
f943fe0f | 537 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 538 | } else { |
f943fe0f | 539 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 540 | if (class->name_version > 1) |
f943fe0f | 541 | printk(KERN_CONT "#%d", class->name_version); |
fbb9ce95 | 542 | if (class->subclass) |
f943fe0f | 543 | printk(KERN_CONT "/%d", class->subclass); |
fbb9ce95 | 544 | } |
e5e78d08 SR |
545 | } |
546 | ||
547 | static void print_lock_name(struct lock_class *class) | |
548 | { | |
549 | char usage[LOCK_USAGE_CHARS]; | |
550 | ||
551 | get_usage_chars(class, usage); | |
552 | ||
f943fe0f | 553 | printk(KERN_CONT " ("); |
e5e78d08 | 554 | __print_lock_name(class); |
f943fe0f | 555 | printk(KERN_CONT "){%s}", usage); |
fbb9ce95 IM |
556 | } |
557 | ||
558 | static void print_lockdep_cache(struct lockdep_map *lock) | |
559 | { | |
560 | const char *name; | |
9281acea | 561 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
562 | |
563 | name = lock->name; | |
564 | if (!name) | |
565 | name = __get_key_name(lock->key->subkeys, str); | |
566 | ||
f943fe0f | 567 | printk(KERN_CONT "%s", name); |
fbb9ce95 IM |
568 | } |
569 | ||
570 | static void print_lock(struct held_lock *hlock) | |
571 | { | |
d7bc3197 PZ |
572 | /* |
573 | * We can be called locklessly through debug_show_all_locks() so be | |
574 | * extra careful, the hlock might have been released and cleared. | |
575 | */ | |
576 | unsigned int class_idx = hlock->class_idx; | |
577 | ||
578 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ | |
579 | barrier(); | |
580 | ||
581 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { | |
f943fe0f | 582 | printk(KERN_CONT "<RELEASED>\n"); |
d7bc3197 PZ |
583 | return; |
584 | } | |
585 | ||
b3c39758 | 586 | printk(KERN_CONT "%p", hlock->instance); |
d7bc3197 | 587 | print_lock_name(lock_classes + class_idx - 1); |
b3c39758 | 588 | printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip); |
fbb9ce95 IM |
589 | } |
590 | ||
8cc05c71 | 591 | static void lockdep_print_held_locks(struct task_struct *p) |
fbb9ce95 | 592 | { |
8cc05c71 | 593 | int i, depth = READ_ONCE(p->lockdep_depth); |
fbb9ce95 | 594 | |
8cc05c71 TH |
595 | if (!depth) |
596 | printk("no locks held by %s/%d.\n", p->comm, task_pid_nr(p)); | |
597 | else | |
598 | printk("%d lock%s held by %s/%d:\n", depth, | |
599 | depth > 1 ? "s" : "", p->comm, task_pid_nr(p)); | |
600 | /* | |
601 | * It's not reliable to print a task's held locks if it's not sleeping | |
602 | * and it's not the current task. | |
603 | */ | |
604 | if (p->state == TASK_RUNNING && p != current) | |
fbb9ce95 | 605 | return; |
fbb9ce95 IM |
606 | for (i = 0; i < depth; i++) { |
607 | printk(" #%d: ", i); | |
8cc05c71 | 608 | print_lock(p->held_locks + i); |
fbb9ce95 IM |
609 | } |
610 | } | |
fbb9ce95 | 611 | |
fbdc4b9a | 612 | static void print_kernel_ident(void) |
8e18257d | 613 | { |
fbdc4b9a | 614 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 615 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
616 | init_utsname()->version, |
617 | print_tainted()); | |
8e18257d PZ |
618 | } |
619 | ||
620 | static int very_verbose(struct lock_class *class) | |
621 | { | |
622 | #if VERY_VERBOSE | |
623 | return class_filter(class); | |
624 | #endif | |
625 | return 0; | |
626 | } | |
627 | ||
fbb9ce95 | 628 | /* |
8e18257d | 629 | * Is this the address of a static object: |
fbb9ce95 | 630 | */ |
8dce7a9a | 631 | #ifdef __KERNEL__ |
108c1485 | 632 | static int static_obj(const void *obj) |
fbb9ce95 | 633 | { |
8e18257d PZ |
634 | unsigned long start = (unsigned long) &_stext, |
635 | end = (unsigned long) &_end, | |
636 | addr = (unsigned long) obj; | |
8e18257d | 637 | |
7a5da02d GS |
638 | if (arch_is_kernel_initmem_freed(addr)) |
639 | return 0; | |
640 | ||
fbb9ce95 | 641 | /* |
8e18257d | 642 | * static variable? |
fbb9ce95 | 643 | */ |
8e18257d PZ |
644 | if ((addr >= start) && (addr < end)) |
645 | return 1; | |
fbb9ce95 | 646 | |
2a9ad18d MF |
647 | if (arch_is_kernel_data(addr)) |
648 | return 1; | |
649 | ||
fbb9ce95 | 650 | /* |
10fad5e4 | 651 | * in-kernel percpu var? |
fbb9ce95 | 652 | */ |
10fad5e4 TH |
653 | if (is_kernel_percpu_address(addr)) |
654 | return 1; | |
fbb9ce95 | 655 | |
8e18257d | 656 | /* |
10fad5e4 | 657 | * module static or percpu var? |
8e18257d | 658 | */ |
10fad5e4 | 659 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 660 | } |
8dce7a9a | 661 | #endif |
99de055a | 662 | |
fbb9ce95 | 663 | /* |
8e18257d | 664 | * To make lock name printouts unique, we calculate a unique |
fe27b0de BVA |
665 | * class->name_version generation counter. The caller must hold the graph |
666 | * lock. | |
fbb9ce95 | 667 | */ |
8e18257d | 668 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 669 | { |
8e18257d PZ |
670 | struct lock_class *class; |
671 | int count = 0; | |
fbb9ce95 | 672 | |
8e18257d | 673 | if (!new_class->name) |
fbb9ce95 IM |
674 | return 0; |
675 | ||
fe27b0de | 676 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
677 | if (new_class->key - new_class->subclass == class->key) |
678 | return class->name_version; | |
679 | if (class->name && !strcmp(class->name, new_class->name)) | |
680 | count = max(count, class->name_version); | |
681 | } | |
fbb9ce95 | 682 | |
8e18257d | 683 | return count + 1; |
fbb9ce95 IM |
684 | } |
685 | ||
8e18257d | 686 | static inline struct lock_class * |
08f36ff6 | 687 | look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass) |
fbb9ce95 | 688 | { |
8e18257d | 689 | struct lockdep_subclass_key *key; |
a63f38cc | 690 | struct hlist_head *hash_head; |
8e18257d | 691 | struct lock_class *class; |
fbb9ce95 | 692 | |
4ba053c0 HM |
693 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
694 | debug_locks_off(); | |
695 | printk(KERN_ERR | |
696 | "BUG: looking up invalid subclass: %u\n", subclass); | |
697 | printk(KERN_ERR | |
698 | "turning off the locking correctness validator.\n"); | |
699 | dump_stack(); | |
700 | return NULL; | |
701 | } | |
702 | ||
8e18257d | 703 | /* |
64f29d1b MW |
704 | * If it is not initialised then it has never been locked, |
705 | * so it won't be present in the hash table. | |
8e18257d | 706 | */ |
64f29d1b MW |
707 | if (unlikely(!lock->key)) |
708 | return NULL; | |
fbb9ce95 | 709 | |
8e18257d PZ |
710 | /* |
711 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
712 | * lock_class_key variable is passed in through the mutex_init() | |
713 | * (or spin_lock_init()) call - which acts as the key. For static | |
714 | * locks we use the lock object itself as the key. | |
715 | */ | |
4b32d0a4 PZ |
716 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
717 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 718 | |
8e18257d | 719 | key = lock->key->subkeys + subclass; |
ca268c69 | 720 | |
8e18257d | 721 | hash_head = classhashentry(key); |
74c383f1 | 722 | |
8e18257d | 723 | /* |
35a9393c | 724 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 725 | */ |
35a9393c PZ |
726 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
727 | return NULL; | |
728 | ||
a63f38cc | 729 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
4b32d0a4 | 730 | if (class->key == key) { |
0119fee4 PZ |
731 | /* |
732 | * Huh! same key, different name? Did someone trample | |
733 | * on some memory? We're most confused. | |
734 | */ | |
4b32d0a4 | 735 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 736 | return class; |
4b32d0a4 PZ |
737 | } |
738 | } | |
fbb9ce95 | 739 | |
64f29d1b MW |
740 | return NULL; |
741 | } | |
742 | ||
743 | /* | |
744 | * Static locks do not have their class-keys yet - for them the key is | |
745 | * the lock object itself. If the lock is in the per cpu area, the | |
746 | * canonical address of the lock (per cpu offset removed) is used. | |
747 | */ | |
748 | static bool assign_lock_key(struct lockdep_map *lock) | |
749 | { | |
750 | unsigned long can_addr, addr = (unsigned long)lock; | |
751 | ||
4bf50862 BVA |
752 | #ifdef __KERNEL__ |
753 | /* | |
754 | * lockdep_free_key_range() assumes that struct lock_class_key | |
755 | * objects do not overlap. Since we use the address of lock | |
756 | * objects as class key for static objects, check whether the | |
757 | * size of lock_class_key objects does not exceed the size of | |
758 | * the smallest lock object. | |
759 | */ | |
760 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(raw_spinlock_t)); | |
761 | #endif | |
762 | ||
64f29d1b MW |
763 | if (__is_kernel_percpu_address(addr, &can_addr)) |
764 | lock->key = (void *)can_addr; | |
765 | else if (__is_module_percpu_address(addr, &can_addr)) | |
766 | lock->key = (void *)can_addr; | |
767 | else if (static_obj(lock)) | |
768 | lock->key = (void *)lock; | |
769 | else { | |
770 | /* Debug-check: all keys must be persistent! */ | |
771 | debug_locks_off(); | |
772 | pr_err("INFO: trying to register non-static key.\n"); | |
773 | pr_err("the code is fine but needs lockdep annotation.\n"); | |
774 | pr_err("turning off the locking correctness validator.\n"); | |
775 | dump_stack(); | |
776 | return false; | |
777 | } | |
778 | ||
779 | return true; | |
fbb9ce95 IM |
780 | } |
781 | ||
72dcd505 PZ |
782 | #ifdef CONFIG_DEBUG_LOCKDEP |
783 | ||
b526b2e3 BVA |
784 | /* Check whether element @e occurs in list @h */ |
785 | static bool in_list(struct list_head *e, struct list_head *h) | |
786 | { | |
787 | struct list_head *f; | |
788 | ||
789 | list_for_each(f, h) { | |
790 | if (e == f) | |
791 | return true; | |
792 | } | |
793 | ||
794 | return false; | |
795 | } | |
796 | ||
797 | /* | |
798 | * Check whether entry @e occurs in any of the locks_after or locks_before | |
799 | * lists. | |
800 | */ | |
801 | static bool in_any_class_list(struct list_head *e) | |
802 | { | |
803 | struct lock_class *class; | |
804 | int i; | |
805 | ||
806 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { | |
807 | class = &lock_classes[i]; | |
808 | if (in_list(e, &class->locks_after) || | |
809 | in_list(e, &class->locks_before)) | |
810 | return true; | |
811 | } | |
812 | return false; | |
813 | } | |
814 | ||
815 | static bool class_lock_list_valid(struct lock_class *c, struct list_head *h) | |
816 | { | |
817 | struct lock_list *e; | |
818 | ||
819 | list_for_each_entry(e, h, entry) { | |
820 | if (e->links_to != c) { | |
821 | printk(KERN_INFO "class %s: mismatch for lock entry %ld; class %s <> %s", | |
822 | c->name ? : "(?)", | |
823 | (unsigned long)(e - list_entries), | |
824 | e->links_to && e->links_to->name ? | |
825 | e->links_to->name : "(?)", | |
826 | e->class && e->class->name ? e->class->name : | |
827 | "(?)"); | |
828 | return false; | |
829 | } | |
830 | } | |
831 | return true; | |
832 | } | |
833 | ||
3fe7522f AB |
834 | #ifdef CONFIG_PROVE_LOCKING |
835 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; | |
836 | #endif | |
b526b2e3 BVA |
837 | |
838 | static bool check_lock_chain_key(struct lock_chain *chain) | |
839 | { | |
840 | #ifdef CONFIG_PROVE_LOCKING | |
841 | u64 chain_key = 0; | |
842 | int i; | |
843 | ||
844 | for (i = chain->base; i < chain->base + chain->depth; i++) | |
845 | chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1); | |
846 | /* | |
847 | * The 'unsigned long long' casts avoid that a compiler warning | |
848 | * is reported when building tools/lib/lockdep. | |
849 | */ | |
72dcd505 | 850 | if (chain->chain_key != chain_key) { |
b526b2e3 BVA |
851 | printk(KERN_INFO "chain %lld: key %#llx <> %#llx\n", |
852 | (unsigned long long)(chain - lock_chains), | |
853 | (unsigned long long)chain->chain_key, | |
854 | (unsigned long long)chain_key); | |
72dcd505 PZ |
855 | return false; |
856 | } | |
b526b2e3 | 857 | #endif |
72dcd505 | 858 | return true; |
b526b2e3 BVA |
859 | } |
860 | ||
861 | static bool in_any_zapped_class_list(struct lock_class *class) | |
862 | { | |
863 | struct pending_free *pf; | |
864 | int i; | |
865 | ||
72dcd505 | 866 | for (i = 0, pf = delayed_free.pf; i < ARRAY_SIZE(delayed_free.pf); i++, pf++) { |
b526b2e3 BVA |
867 | if (in_list(&class->lock_entry, &pf->zapped)) |
868 | return true; | |
72dcd505 | 869 | } |
b526b2e3 BVA |
870 | |
871 | return false; | |
872 | } | |
873 | ||
72dcd505 | 874 | static bool __check_data_structures(void) |
b526b2e3 BVA |
875 | { |
876 | struct lock_class *class; | |
877 | struct lock_chain *chain; | |
878 | struct hlist_head *head; | |
879 | struct lock_list *e; | |
880 | int i; | |
881 | ||
882 | /* Check whether all classes occur in a lock list. */ | |
883 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { | |
884 | class = &lock_classes[i]; | |
885 | if (!in_list(&class->lock_entry, &all_lock_classes) && | |
886 | !in_list(&class->lock_entry, &free_lock_classes) && | |
887 | !in_any_zapped_class_list(class)) { | |
888 | printk(KERN_INFO "class %px/%s is not in any class list\n", | |
889 | class, class->name ? : "(?)"); | |
890 | return false; | |
b526b2e3 BVA |
891 | } |
892 | } | |
893 | ||
894 | /* Check whether all classes have valid lock lists. */ | |
895 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { | |
896 | class = &lock_classes[i]; | |
897 | if (!class_lock_list_valid(class, &class->locks_before)) | |
898 | return false; | |
899 | if (!class_lock_list_valid(class, &class->locks_after)) | |
900 | return false; | |
901 | } | |
902 | ||
903 | /* Check the chain_key of all lock chains. */ | |
904 | for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) { | |
905 | head = chainhash_table + i; | |
906 | hlist_for_each_entry_rcu(chain, head, entry) { | |
907 | if (!check_lock_chain_key(chain)) | |
908 | return false; | |
909 | } | |
910 | } | |
911 | ||
912 | /* | |
913 | * Check whether all list entries that are in use occur in a class | |
914 | * lock list. | |
915 | */ | |
916 | for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) { | |
917 | e = list_entries + i; | |
918 | if (!in_any_class_list(&e->entry)) { | |
919 | printk(KERN_INFO "list entry %d is not in any class list; class %s <> %s\n", | |
920 | (unsigned int)(e - list_entries), | |
921 | e->class->name ? : "(?)", | |
922 | e->links_to->name ? : "(?)"); | |
923 | return false; | |
924 | } | |
925 | } | |
926 | ||
927 | /* | |
928 | * Check whether all list entries that are not in use do not occur in | |
929 | * a class lock list. | |
930 | */ | |
931 | for_each_clear_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) { | |
932 | e = list_entries + i; | |
933 | if (in_any_class_list(&e->entry)) { | |
934 | printk(KERN_INFO "list entry %d occurs in a class list; class %s <> %s\n", | |
935 | (unsigned int)(e - list_entries), | |
936 | e->class && e->class->name ? e->class->name : | |
937 | "(?)", | |
938 | e->links_to && e->links_to->name ? | |
939 | e->links_to->name : "(?)"); | |
940 | return false; | |
941 | } | |
942 | } | |
943 | ||
944 | return true; | |
945 | } | |
946 | ||
72dcd505 PZ |
947 | int check_consistency = 0; |
948 | module_param(check_consistency, int, 0644); | |
949 | ||
950 | static void check_data_structures(void) | |
951 | { | |
952 | static bool once = false; | |
953 | ||
954 | if (check_consistency && !once) { | |
955 | if (!__check_data_structures()) { | |
956 | once = true; | |
957 | WARN_ON(once); | |
958 | } | |
959 | } | |
960 | } | |
961 | ||
962 | #else /* CONFIG_DEBUG_LOCKDEP */ | |
963 | ||
964 | static inline void check_data_structures(void) { } | |
965 | ||
966 | #endif /* CONFIG_DEBUG_LOCKDEP */ | |
967 | ||
feb0a386 | 968 | /* |
a0b0fd53 BVA |
969 | * Initialize the lock_classes[] array elements, the free_lock_classes list |
970 | * and also the delayed_free structure. | |
feb0a386 BVA |
971 | */ |
972 | static void init_data_structures_once(void) | |
973 | { | |
0126574f | 974 | static bool ds_initialized, rcu_head_initialized; |
feb0a386 BVA |
975 | int i; |
976 | ||
0126574f | 977 | if (likely(rcu_head_initialized)) |
feb0a386 BVA |
978 | return; |
979 | ||
0126574f BVA |
980 | if (system_state >= SYSTEM_SCHEDULING) { |
981 | init_rcu_head(&delayed_free.rcu_head); | |
982 | rcu_head_initialized = true; | |
983 | } | |
984 | ||
985 | if (ds_initialized) | |
986 | return; | |
987 | ||
988 | ds_initialized = true; | |
feb0a386 | 989 | |
a0b0fd53 BVA |
990 | INIT_LIST_HEAD(&delayed_free.pf[0].zapped); |
991 | INIT_LIST_HEAD(&delayed_free.pf[1].zapped); | |
992 | ||
feb0a386 | 993 | for (i = 0; i < ARRAY_SIZE(lock_classes); i++) { |
a0b0fd53 | 994 | list_add_tail(&lock_classes[i].lock_entry, &free_lock_classes); |
feb0a386 BVA |
995 | INIT_LIST_HEAD(&lock_classes[i].locks_after); |
996 | INIT_LIST_HEAD(&lock_classes[i].locks_before); | |
997 | } | |
998 | } | |
999 | ||
108c1485 BVA |
1000 | static inline struct hlist_head *keyhashentry(const struct lock_class_key *key) |
1001 | { | |
1002 | unsigned long hash = hash_long((uintptr_t)key, KEYHASH_BITS); | |
1003 | ||
1004 | return lock_keys_hash + hash; | |
1005 | } | |
1006 | ||
1007 | /* Register a dynamically allocated key. */ | |
1008 | void lockdep_register_key(struct lock_class_key *key) | |
1009 | { | |
1010 | struct hlist_head *hash_head; | |
1011 | struct lock_class_key *k; | |
1012 | unsigned long flags; | |
1013 | ||
1014 | if (WARN_ON_ONCE(static_obj(key))) | |
1015 | return; | |
1016 | hash_head = keyhashentry(key); | |
1017 | ||
1018 | raw_local_irq_save(flags); | |
1019 | if (!graph_lock()) | |
1020 | goto restore_irqs; | |
1021 | hlist_for_each_entry_rcu(k, hash_head, hash_entry) { | |
1022 | if (WARN_ON_ONCE(k == key)) | |
1023 | goto out_unlock; | |
1024 | } | |
1025 | hlist_add_head_rcu(&key->hash_entry, hash_head); | |
1026 | out_unlock: | |
1027 | graph_unlock(); | |
1028 | restore_irqs: | |
1029 | raw_local_irq_restore(flags); | |
1030 | } | |
1031 | EXPORT_SYMBOL_GPL(lockdep_register_key); | |
1032 | ||
1033 | /* Check whether a key has been registered as a dynamic key. */ | |
1034 | static bool is_dynamic_key(const struct lock_class_key *key) | |
1035 | { | |
1036 | struct hlist_head *hash_head; | |
1037 | struct lock_class_key *k; | |
1038 | bool found = false; | |
1039 | ||
1040 | if (WARN_ON_ONCE(static_obj(key))) | |
1041 | return false; | |
1042 | ||
1043 | /* | |
1044 | * If lock debugging is disabled lock_keys_hash[] may contain | |
1045 | * pointers to memory that has already been freed. Avoid triggering | |
1046 | * a use-after-free in that case by returning early. | |
1047 | */ | |
1048 | if (!debug_locks) | |
1049 | return true; | |
1050 | ||
1051 | hash_head = keyhashentry(key); | |
1052 | ||
1053 | rcu_read_lock(); | |
1054 | hlist_for_each_entry_rcu(k, hash_head, hash_entry) { | |
1055 | if (k == key) { | |
1056 | found = true; | |
1057 | break; | |
1058 | } | |
1059 | } | |
1060 | rcu_read_unlock(); | |
1061 | ||
1062 | return found; | |
1063 | } | |
1064 | ||
fbb9ce95 | 1065 | /* |
8e18257d PZ |
1066 | * Register a lock's class in the hash-table, if the class is not present |
1067 | * yet. Otherwise we look it up. We cache the result in the lock object | |
1068 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 1069 | */ |
c003ed92 | 1070 | static struct lock_class * |
8e18257d | 1071 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
fbb9ce95 | 1072 | { |
8e18257d | 1073 | struct lockdep_subclass_key *key; |
a63f38cc | 1074 | struct hlist_head *hash_head; |
8e18257d | 1075 | struct lock_class *class; |
35a9393c PZ |
1076 | |
1077 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
1078 | |
1079 | class = look_up_lock_class(lock, subclass); | |
64f29d1b | 1080 | if (likely(class)) |
87cdee71 | 1081 | goto out_set_class_cache; |
8e18257d | 1082 | |
64f29d1b MW |
1083 | if (!lock->key) { |
1084 | if (!assign_lock_key(lock)) | |
1085 | return NULL; | |
108c1485 | 1086 | } else if (!static_obj(lock->key) && !is_dynamic_key(lock->key)) { |
8e18257d PZ |
1087 | return NULL; |
1088 | } | |
1089 | ||
1090 | key = lock->key->subkeys + subclass; | |
1091 | hash_head = classhashentry(key); | |
1092 | ||
8e18257d | 1093 | if (!graph_lock()) { |
8e18257d PZ |
1094 | return NULL; |
1095 | } | |
1096 | /* | |
1097 | * We have to do the hash-walk again, to avoid races | |
1098 | * with another CPU: | |
1099 | */ | |
a63f38cc | 1100 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
1101 | if (class->key == key) |
1102 | goto out_unlock_set; | |
35a9393c PZ |
1103 | } |
1104 | ||
feb0a386 BVA |
1105 | init_data_structures_once(); |
1106 | ||
a0b0fd53 BVA |
1107 | /* Allocate a new lock class and add it to the hash. */ |
1108 | class = list_first_entry_or_null(&free_lock_classes, typeof(*class), | |
1109 | lock_entry); | |
1110 | if (!class) { | |
8e18257d | 1111 | if (!debug_locks_off_graph_unlock()) { |
8e18257d PZ |
1112 | return NULL; |
1113 | } | |
8e18257d | 1114 | |
2c522836 | 1115 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 1116 | dump_stack(); |
8e18257d PZ |
1117 | return NULL; |
1118 | } | |
a0b0fd53 | 1119 | nr_lock_classes++; |
bd6d29c2 | 1120 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
1121 | class->key = key; |
1122 | class->name = lock->name; | |
1123 | class->subclass = subclass; | |
feb0a386 BVA |
1124 | WARN_ON_ONCE(!list_empty(&class->locks_before)); |
1125 | WARN_ON_ONCE(!list_empty(&class->locks_after)); | |
8e18257d PZ |
1126 | class->name_version = count_matching_names(class); |
1127 | /* | |
1128 | * We use RCU's safe list-add method to make | |
1129 | * parallel walking of the hash-list safe: | |
1130 | */ | |
a63f38cc | 1131 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
1481197b | 1132 | /* |
a0b0fd53 BVA |
1133 | * Remove the class from the free list and add it to the global list |
1134 | * of classes. | |
1481197b | 1135 | */ |
a0b0fd53 | 1136 | list_move_tail(&class->lock_entry, &all_lock_classes); |
8e18257d PZ |
1137 | |
1138 | if (verbose(class)) { | |
1139 | graph_unlock(); | |
8e18257d | 1140 | |
04860d48 | 1141 | printk("\nnew class %px: %s", class->key, class->name); |
8e18257d | 1142 | if (class->name_version > 1) |
f943fe0f DV |
1143 | printk(KERN_CONT "#%d", class->name_version); |
1144 | printk(KERN_CONT "\n"); | |
8e18257d PZ |
1145 | dump_stack(); |
1146 | ||
8e18257d | 1147 | if (!graph_lock()) { |
8e18257d PZ |
1148 | return NULL; |
1149 | } | |
1150 | } | |
1151 | out_unlock_set: | |
1152 | graph_unlock(); | |
8e18257d | 1153 | |
87cdee71 | 1154 | out_set_class_cache: |
8e18257d | 1155 | if (!subclass || force) |
62016250 HM |
1156 | lock->class_cache[0] = class; |
1157 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
1158 | lock->class_cache[subclass] = class; | |
8e18257d | 1159 | |
0119fee4 PZ |
1160 | /* |
1161 | * Hash collision, did we smoke some? We found a class with a matching | |
1162 | * hash but the subclass -- which is hashed in -- didn't match. | |
1163 | */ | |
8e18257d PZ |
1164 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
1165 | return NULL; | |
1166 | ||
1167 | return class; | |
1168 | } | |
1169 | ||
1170 | #ifdef CONFIG_PROVE_LOCKING | |
1171 | /* | |
1172 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
1173 | * with NULL on failure) | |
1174 | */ | |
1175 | static struct lock_list *alloc_list_entry(void) | |
1176 | { | |
ace35a7a BVA |
1177 | int idx = find_first_zero_bit(list_entries_in_use, |
1178 | ARRAY_SIZE(list_entries)); | |
1179 | ||
1180 | if (idx >= ARRAY_SIZE(list_entries)) { | |
8e18257d PZ |
1181 | if (!debug_locks_off_graph_unlock()) |
1182 | return NULL; | |
1183 | ||
2c522836 | 1184 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 1185 | dump_stack(); |
8e18257d PZ |
1186 | return NULL; |
1187 | } | |
ace35a7a BVA |
1188 | nr_list_entries++; |
1189 | __set_bit(idx, list_entries_in_use); | |
1190 | return list_entries + idx; | |
8e18257d PZ |
1191 | } |
1192 | ||
1193 | /* | |
1194 | * Add a new dependency to the head of the list: | |
1195 | */ | |
86cffb80 BVA |
1196 | static int add_lock_to_list(struct lock_class *this, |
1197 | struct lock_class *links_to, struct list_head *head, | |
83f06168 | 1198 | unsigned long ip, int distance, |
c120bce7 | 1199 | struct lock_trace *trace) |
8e18257d PZ |
1200 | { |
1201 | struct lock_list *entry; | |
1202 | /* | |
1203 | * Lock not present yet - get a new dependency struct and | |
1204 | * add it to the list: | |
1205 | */ | |
1206 | entry = alloc_list_entry(); | |
1207 | if (!entry) | |
1208 | return 0; | |
1209 | ||
74870172 | 1210 | entry->class = this; |
86cffb80 | 1211 | entry->links_to = links_to; |
74870172 | 1212 | entry->distance = distance; |
4726f2a6 | 1213 | entry->trace = *trace; |
8e18257d | 1214 | /* |
35a9393c PZ |
1215 | * Both allocation and removal are done under the graph lock; but |
1216 | * iteration is under RCU-sched; see look_up_lock_class() and | |
1217 | * lockdep_free_key_range(). | |
8e18257d PZ |
1218 | */ |
1219 | list_add_tail_rcu(&entry->entry, head); | |
1220 | ||
1221 | return 1; | |
1222 | } | |
1223 | ||
98c33edd PZ |
1224 | /* |
1225 | * For good efficiency of modular, we use power of 2 | |
1226 | */ | |
af012961 PZ |
1227 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
1228 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
1229 | ||
98c33edd PZ |
1230 | /* |
1231 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
1232 | * breadth-first search(BFS)algorithem, by which we can build |
1233 | * the shortest path from the next lock to be acquired to the | |
1234 | * previous held lock if there is a circular between them. | |
98c33edd | 1235 | */ |
af012961 PZ |
1236 | struct circular_queue { |
1237 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
1238 | unsigned int front, rear; | |
1239 | }; | |
1240 | ||
1241 | static struct circular_queue lock_cq; | |
af012961 | 1242 | |
12f3dfd0 | 1243 | unsigned int max_bfs_queue_depth; |
af012961 | 1244 | |
e351b660 ML |
1245 | static unsigned int lockdep_dependency_gen_id; |
1246 | ||
af012961 PZ |
1247 | static inline void __cq_init(struct circular_queue *cq) |
1248 | { | |
1249 | cq->front = cq->rear = 0; | |
e351b660 | 1250 | lockdep_dependency_gen_id++; |
af012961 PZ |
1251 | } |
1252 | ||
1253 | static inline int __cq_empty(struct circular_queue *cq) | |
1254 | { | |
1255 | return (cq->front == cq->rear); | |
1256 | } | |
1257 | ||
1258 | static inline int __cq_full(struct circular_queue *cq) | |
1259 | { | |
1260 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
1261 | } | |
1262 | ||
1263 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
1264 | { | |
1265 | if (__cq_full(cq)) | |
1266 | return -1; | |
1267 | ||
1268 | cq->element[cq->rear] = elem; | |
1269 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
1270 | return 0; | |
1271 | } | |
1272 | ||
1273 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
1274 | { | |
1275 | if (__cq_empty(cq)) | |
1276 | return -1; | |
1277 | ||
1278 | *elem = cq->element[cq->front]; | |
1279 | cq->front = (cq->front + 1) & CQ_MASK; | |
1280 | return 0; | |
1281 | } | |
1282 | ||
1283 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
1284 | { | |
1285 | return (cq->rear - cq->front) & CQ_MASK; | |
1286 | } | |
1287 | ||
1288 | static inline void mark_lock_accessed(struct lock_list *lock, | |
1289 | struct lock_list *parent) | |
1290 | { | |
1291 | unsigned long nr; | |
98c33edd | 1292 | |
af012961 | 1293 | nr = lock - list_entries; |
ace35a7a | 1294 | WARN_ON(nr >= ARRAY_SIZE(list_entries)); /* Out-of-bounds, input fail */ |
af012961 | 1295 | lock->parent = parent; |
e351b660 | 1296 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
1297 | } |
1298 | ||
1299 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
1300 | { | |
1301 | unsigned long nr; | |
98c33edd | 1302 | |
af012961 | 1303 | nr = lock - list_entries; |
ace35a7a | 1304 | WARN_ON(nr >= ARRAY_SIZE(list_entries)); /* Out-of-bounds, input fail */ |
e351b660 | 1305 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
1306 | } |
1307 | ||
1308 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
1309 | { | |
1310 | return child->parent; | |
1311 | } | |
1312 | ||
1313 | static inline int get_lock_depth(struct lock_list *child) | |
1314 | { | |
1315 | int depth = 0; | |
1316 | struct lock_list *parent; | |
1317 | ||
1318 | while ((parent = get_lock_parent(child))) { | |
1319 | child = parent; | |
1320 | depth++; | |
1321 | } | |
1322 | return depth; | |
1323 | } | |
1324 | ||
9e2d551e | 1325 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
1326 | void *data, |
1327 | int (*match)(struct lock_list *entry, void *data), | |
1328 | struct lock_list **target_entry, | |
1329 | int forward) | |
c94aa5ca ML |
1330 | { |
1331 | struct lock_list *entry; | |
d588e461 | 1332 | struct list_head *head; |
c94aa5ca ML |
1333 | struct circular_queue *cq = &lock_cq; |
1334 | int ret = 1; | |
1335 | ||
9e2d551e | 1336 | if (match(source_entry, data)) { |
c94aa5ca ML |
1337 | *target_entry = source_entry; |
1338 | ret = 0; | |
1339 | goto exit; | |
1340 | } | |
1341 | ||
d588e461 ML |
1342 | if (forward) |
1343 | head = &source_entry->class->locks_after; | |
1344 | else | |
1345 | head = &source_entry->class->locks_before; | |
1346 | ||
1347 | if (list_empty(head)) | |
1348 | goto exit; | |
1349 | ||
1350 | __cq_init(cq); | |
c94aa5ca ML |
1351 | __cq_enqueue(cq, (unsigned long)source_entry); |
1352 | ||
1353 | while (!__cq_empty(cq)) { | |
1354 | struct lock_list *lock; | |
c94aa5ca ML |
1355 | |
1356 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1357 | ||
1358 | if (!lock->class) { | |
1359 | ret = -2; | |
1360 | goto exit; | |
1361 | } | |
1362 | ||
1363 | if (forward) | |
1364 | head = &lock->class->locks_after; | |
1365 | else | |
1366 | head = &lock->class->locks_before; | |
1367 | ||
35a9393c PZ |
1368 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1369 | ||
1370 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1371 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1372 | unsigned int cq_depth; |
c94aa5ca | 1373 | mark_lock_accessed(entry, lock); |
9e2d551e | 1374 | if (match(entry, data)) { |
c94aa5ca ML |
1375 | *target_entry = entry; |
1376 | ret = 0; | |
1377 | goto exit; | |
1378 | } | |
1379 | ||
1380 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1381 | ret = -1; | |
1382 | goto exit; | |
1383 | } | |
12f3dfd0 ML |
1384 | cq_depth = __cq_get_elem_count(cq); |
1385 | if (max_bfs_queue_depth < cq_depth) | |
1386 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1387 | } |
1388 | } | |
1389 | } | |
1390 | exit: | |
1391 | return ret; | |
1392 | } | |
1393 | ||
d7aaba14 | 1394 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1395 | void *data, |
1396 | int (*match)(struct lock_list *entry, void *data), | |
1397 | struct lock_list **target_entry) | |
c94aa5ca | 1398 | { |
9e2d551e | 1399 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1400 | |
1401 | } | |
1402 | ||
d7aaba14 | 1403 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1404 | void *data, |
1405 | int (*match)(struct lock_list *entry, void *data), | |
1406 | struct lock_list **target_entry) | |
c94aa5ca | 1407 | { |
9e2d551e | 1408 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1409 | |
1410 | } | |
1411 | ||
8e18257d PZ |
1412 | /* |
1413 | * Recursive, forwards-direction lock-dependency checking, used for | |
1414 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1415 | * checking. | |
8e18257d | 1416 | */ |
8e18257d | 1417 | |
c120bce7 TG |
1418 | static void print_lock_trace(struct lock_trace *trace, unsigned int spaces) |
1419 | { | |
1420 | unsigned long *entries = stack_trace + trace->offset; | |
1421 | ||
1422 | stack_trace_print(entries, trace->nr_entries, spaces); | |
1423 | } | |
1424 | ||
8e18257d PZ |
1425 | /* |
1426 | * Print a dependency chain entry (this is only done when a deadlock | |
1427 | * has been detected): | |
1428 | */ | |
1429 | static noinline int | |
24208ca7 | 1430 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1431 | { |
1432 | if (debug_locks_silent) | |
1433 | return 0; | |
1434 | printk("\n-> #%u", depth); | |
1435 | print_lock_name(target->class); | |
f943fe0f | 1436 | printk(KERN_CONT ":\n"); |
c120bce7 | 1437 | print_lock_trace(&target->trace, 6); |
8e18257d PZ |
1438 | return 0; |
1439 | } | |
1440 | ||
f4185812 SR |
1441 | static void |
1442 | print_circular_lock_scenario(struct held_lock *src, | |
1443 | struct held_lock *tgt, | |
1444 | struct lock_list *prt) | |
1445 | { | |
1446 | struct lock_class *source = hlock_class(src); | |
1447 | struct lock_class *target = hlock_class(tgt); | |
1448 | struct lock_class *parent = prt->class; | |
1449 | ||
1450 | /* | |
1451 | * A direct locking problem where unsafe_class lock is taken | |
1452 | * directly by safe_class lock, then all we need to show | |
1453 | * is the deadlock scenario, as it is obvious that the | |
1454 | * unsafe lock is taken under the safe lock. | |
1455 | * | |
1456 | * But if there is a chain instead, where the safe lock takes | |
1457 | * an intermediate lock (middle_class) where this lock is | |
1458 | * not the same as the safe lock, then the lock chain is | |
1459 | * used to describe the problem. Otherwise we would need | |
1460 | * to show a different CPU case for each link in the chain | |
1461 | * from the safe_class lock to the unsafe_class lock. | |
1462 | */ | |
1463 | if (parent != source) { | |
1464 | printk("Chain exists of:\n "); | |
1465 | __print_lock_name(source); | |
f943fe0f | 1466 | printk(KERN_CONT " --> "); |
f4185812 | 1467 | __print_lock_name(parent); |
f943fe0f | 1468 | printk(KERN_CONT " --> "); |
f4185812 | 1469 | __print_lock_name(target); |
f943fe0f | 1470 | printk(KERN_CONT "\n\n"); |
f4185812 SR |
1471 | } |
1472 | ||
e966eaee IM |
1473 | printk(" Possible unsafe locking scenario:\n\n"); |
1474 | printk(" CPU0 CPU1\n"); | |
1475 | printk(" ---- ----\n"); | |
1476 | printk(" lock("); | |
1477 | __print_lock_name(target); | |
1478 | printk(KERN_CONT ");\n"); | |
1479 | printk(" lock("); | |
1480 | __print_lock_name(parent); | |
1481 | printk(KERN_CONT ");\n"); | |
1482 | printk(" lock("); | |
1483 | __print_lock_name(target); | |
1484 | printk(KERN_CONT ");\n"); | |
1485 | printk(" lock("); | |
1486 | __print_lock_name(source); | |
1487 | printk(KERN_CONT ");\n"); | |
1488 | printk("\n *** DEADLOCK ***\n\n"); | |
f4185812 SR |
1489 | } |
1490 | ||
8e18257d PZ |
1491 | /* |
1492 | * When a circular dependency is detected, print the | |
1493 | * header first: | |
1494 | */ | |
1495 | static noinline int | |
db0002a3 ML |
1496 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1497 | struct held_lock *check_src, | |
1498 | struct held_lock *check_tgt) | |
8e18257d PZ |
1499 | { |
1500 | struct task_struct *curr = current; | |
1501 | ||
c94aa5ca | 1502 | if (debug_locks_silent) |
8e18257d PZ |
1503 | return 0; |
1504 | ||
681fbec8 | 1505 | pr_warn("\n"); |
a5dd63ef PM |
1506 | pr_warn("======================================================\n"); |
1507 | pr_warn("WARNING: possible circular locking dependency detected\n"); | |
fbdc4b9a | 1508 | print_kernel_ident(); |
a5dd63ef | 1509 | pr_warn("------------------------------------------------------\n"); |
681fbec8 | 1510 | pr_warn("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1511 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1512 | print_lock(check_src); |
383a4bc8 | 1513 | |
e966eaee | 1514 | pr_warn("\nbut task is already holding lock:\n"); |
383a4bc8 | 1515 | |
db0002a3 | 1516 | print_lock(check_tgt); |
681fbec8 PM |
1517 | pr_warn("\nwhich lock already depends on the new lock.\n\n"); |
1518 | pr_warn("\nthe existing dependency chain (in reverse order) is:\n"); | |
8e18257d PZ |
1519 | |
1520 | print_circular_bug_entry(entry, depth); | |
1521 | ||
1522 | return 0; | |
1523 | } | |
1524 | ||
9e2d551e ML |
1525 | static inline int class_equal(struct lock_list *entry, void *data) |
1526 | { | |
1527 | return entry->class == data; | |
1528 | } | |
1529 | ||
db0002a3 | 1530 | static noinline int print_circular_bug(struct lock_list *this, |
b1abe462 TG |
1531 | struct lock_list *target, |
1532 | struct held_lock *check_src, | |
1533 | struct held_lock *check_tgt) | |
8e18257d PZ |
1534 | { |
1535 | struct task_struct *curr = current; | |
c94aa5ca | 1536 | struct lock_list *parent; |
f4185812 | 1537 | struct lock_list *first_parent; |
24208ca7 | 1538 | int depth; |
8e18257d | 1539 | |
c94aa5ca | 1540 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1541 | return 0; |
1542 | ||
e966eaee | 1543 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1544 | return 0; |
1545 | ||
c94aa5ca ML |
1546 | depth = get_lock_depth(target); |
1547 | ||
db0002a3 | 1548 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1549 | |
1550 | parent = get_lock_parent(target); | |
f4185812 | 1551 | first_parent = parent; |
c94aa5ca ML |
1552 | |
1553 | while (parent) { | |
1554 | print_circular_bug_entry(parent, --depth); | |
1555 | parent = get_lock_parent(parent); | |
1556 | } | |
8e18257d PZ |
1557 | |
1558 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1559 | print_circular_lock_scenario(check_src, check_tgt, |
1560 | first_parent); | |
1561 | ||
8e18257d PZ |
1562 | lockdep_print_held_locks(curr); |
1563 | ||
1564 | printk("\nstack backtrace:\n"); | |
1565 | dump_stack(); | |
1566 | ||
1567 | return 0; | |
1568 | } | |
1569 | ||
db0002a3 ML |
1570 | static noinline int print_bfs_bug(int ret) |
1571 | { | |
1572 | if (!debug_locks_off_graph_unlock()) | |
1573 | return 0; | |
1574 | ||
0119fee4 PZ |
1575 | /* |
1576 | * Breadth-first-search failed, graph got corrupted? | |
1577 | */ | |
db0002a3 ML |
1578 | WARN(1, "lockdep bfs error:%d\n", ret); |
1579 | ||
1580 | return 0; | |
1581 | } | |
1582 | ||
ef681026 | 1583 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1584 | { |
ef681026 ML |
1585 | (*(unsigned long *)data)++; |
1586 | return 0; | |
1587 | } | |
419ca3f1 | 1588 | |
5216d530 | 1589 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1590 | { |
1591 | unsigned long count = 0; | |
1592 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1593 | |
ef681026 | 1594 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1595 | |
ef681026 | 1596 | return count; |
419ca3f1 | 1597 | } |
419ca3f1 DM |
1598 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1599 | { | |
1600 | unsigned long ret, flags; | |
ef681026 ML |
1601 | struct lock_list this; |
1602 | ||
1603 | this.parent = NULL; | |
1604 | this.class = class; | |
419ca3f1 | 1605 | |
fcc784be | 1606 | raw_local_irq_save(flags); |
0199c4e6 | 1607 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1608 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1609 | arch_spin_unlock(&lockdep_lock); |
fcc784be | 1610 | raw_local_irq_restore(flags); |
419ca3f1 DM |
1611 | |
1612 | return ret; | |
1613 | } | |
1614 | ||
5216d530 | 1615 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1616 | { |
ef681026 ML |
1617 | unsigned long count = 0; |
1618 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1619 | |
ef681026 | 1620 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1621 | |
ef681026 | 1622 | return count; |
419ca3f1 DM |
1623 | } |
1624 | ||
1625 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1626 | { | |
1627 | unsigned long ret, flags; | |
ef681026 ML |
1628 | struct lock_list this; |
1629 | ||
1630 | this.parent = NULL; | |
1631 | this.class = class; | |
419ca3f1 | 1632 | |
fcc784be | 1633 | raw_local_irq_save(flags); |
0199c4e6 | 1634 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1635 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1636 | arch_spin_unlock(&lockdep_lock); |
fcc784be | 1637 | raw_local_irq_restore(flags); |
419ca3f1 DM |
1638 | |
1639 | return ret; | |
1640 | } | |
1641 | ||
8e18257d PZ |
1642 | /* |
1643 | * Prove that the dependency graph starting at <entry> can not | |
1644 | * lead to <target>. Print an error and return 0 if it does. | |
1645 | */ | |
1646 | static noinline int | |
db0002a3 ML |
1647 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1648 | struct lock_list **target_entry) | |
8e18257d | 1649 | { |
db0002a3 | 1650 | int result; |
8e18257d | 1651 | |
bd6d29c2 | 1652 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1653 | |
d7aaba14 | 1654 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1655 | |
db0002a3 ML |
1656 | return result; |
1657 | } | |
c94aa5ca | 1658 | |
ae813308 PZ |
1659 | static noinline int |
1660 | check_redundant(struct lock_list *root, struct lock_class *target, | |
1661 | struct lock_list **target_entry) | |
1662 | { | |
1663 | int result; | |
1664 | ||
1665 | debug_atomic_inc(nr_redundant_checks); | |
1666 | ||
1667 | result = __bfs_forwards(root, target, class_equal, target_entry); | |
1668 | ||
1669 | return result; | |
1670 | } | |
1671 | ||
81d68a96 | 1672 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
948f8376 FW |
1673 | |
1674 | static inline int usage_accumulate(struct lock_list *entry, void *mask) | |
1675 | { | |
1676 | *(unsigned long *)mask |= entry->class->usage_mask; | |
1677 | ||
1678 | return 0; | |
1679 | } | |
1680 | ||
fbb9ce95 IM |
1681 | /* |
1682 | * Forwards and backwards subgraph searching, for the purposes of | |
1683 | * proving that two subgraphs can be connected by a new dependency | |
1684 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1685 | */ | |
fbb9ce95 | 1686 | |
627f364d | 1687 | static inline int usage_match(struct lock_list *entry, void *mask) |
d7aaba14 | 1688 | { |
627f364d | 1689 | return entry->class->usage_mask & *(unsigned long *)mask; |
d7aaba14 ML |
1690 | } |
1691 | ||
fbb9ce95 IM |
1692 | /* |
1693 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1694 | * at @root->class that matches @bit. |
fbb9ce95 | 1695 | * |
d7aaba14 ML |
1696 | * Return 0 if such a node exists in the subgraph, and put that node |
1697 | * into *@target_entry. | |
fbb9ce95 | 1698 | * |
d7aaba14 ML |
1699 | * Return 1 otherwise and keep *@target_entry unchanged. |
1700 | * Return <0 on error. | |
fbb9ce95 | 1701 | */ |
d7aaba14 | 1702 | static int |
627f364d | 1703 | find_usage_forwards(struct lock_list *root, unsigned long usage_mask, |
d7aaba14 | 1704 | struct lock_list **target_entry) |
fbb9ce95 | 1705 | { |
d7aaba14 | 1706 | int result; |
fbb9ce95 | 1707 | |
bd6d29c2 | 1708 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1709 | |
627f364d | 1710 | result = __bfs_forwards(root, &usage_mask, usage_match, target_entry); |
d7aaba14 ML |
1711 | |
1712 | return result; | |
fbb9ce95 IM |
1713 | } |
1714 | ||
1715 | /* | |
1716 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1717 | * at @root->class that matches @bit. |
fbb9ce95 | 1718 | * |
d7aaba14 ML |
1719 | * Return 0 if such a node exists in the subgraph, and put that node |
1720 | * into *@target_entry. | |
fbb9ce95 | 1721 | * |
d7aaba14 ML |
1722 | * Return 1 otherwise and keep *@target_entry unchanged. |
1723 | * Return <0 on error. | |
fbb9ce95 | 1724 | */ |
d7aaba14 | 1725 | static int |
627f364d | 1726 | find_usage_backwards(struct lock_list *root, unsigned long usage_mask, |
d7aaba14 | 1727 | struct lock_list **target_entry) |
fbb9ce95 | 1728 | { |
d7aaba14 | 1729 | int result; |
fbb9ce95 | 1730 | |
bd6d29c2 | 1731 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1732 | |
627f364d | 1733 | result = __bfs_backwards(root, &usage_mask, usage_match, target_entry); |
f82b217e | 1734 | |
d7aaba14 | 1735 | return result; |
fbb9ce95 IM |
1736 | } |
1737 | ||
af012961 PZ |
1738 | static void print_lock_class_header(struct lock_class *class, int depth) |
1739 | { | |
1740 | int bit; | |
1741 | ||
1742 | printk("%*s->", depth, ""); | |
1743 | print_lock_name(class); | |
8ca2b56c WL |
1744 | #ifdef CONFIG_DEBUG_LOCKDEP |
1745 | printk(KERN_CONT " ops: %lu", debug_class_ops_read(class)); | |
1746 | #endif | |
f943fe0f | 1747 | printk(KERN_CONT " {\n"); |
af012961 PZ |
1748 | |
1749 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1750 | if (class->usage_mask & (1 << bit)) { | |
1751 | int len = depth; | |
1752 | ||
1753 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
f943fe0f | 1754 | len += printk(KERN_CONT " at:\n"); |
c120bce7 | 1755 | print_lock_trace(class->usage_traces + bit, len); |
af012961 PZ |
1756 | } |
1757 | } | |
1758 | printk("%*s }\n", depth, ""); | |
1759 | ||
04860d48 | 1760 | printk("%*s ... key at: [<%px>] %pS\n", |
f943fe0f | 1761 | depth, "", class->key, class->key); |
af012961 PZ |
1762 | } |
1763 | ||
1764 | /* | |
1765 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1766 | */ | |
1767 | static void __used | |
1768 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1769 | struct lock_list *root) | |
1770 | { | |
1771 | struct lock_list *entry = leaf; | |
1772 | int depth; | |
1773 | ||
1774 | /*compute depth from generated tree by BFS*/ | |
1775 | depth = get_lock_depth(leaf); | |
1776 | ||
1777 | do { | |
1778 | print_lock_class_header(entry->class, depth); | |
1779 | printk("%*s ... acquired at:\n", depth, ""); | |
c120bce7 | 1780 | print_lock_trace(&entry->trace, 2); |
af012961 PZ |
1781 | printk("\n"); |
1782 | ||
1783 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1784 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1785 | break; |
1786 | } | |
1787 | ||
1788 | entry = get_lock_parent(entry); | |
1789 | depth--; | |
1790 | } while (entry && (depth >= 0)); | |
1791 | ||
1792 | return; | |
1793 | } | |
d7aaba14 | 1794 | |
3003eba3 SR |
1795 | static void |
1796 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1797 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1798 | struct lock_class *prev_class, |
1799 | struct lock_class *next_class) | |
3003eba3 SR |
1800 | { |
1801 | struct lock_class *safe_class = safe_entry->class; | |
1802 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1803 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1804 | |
1805 | if (middle_class == safe_class) | |
dad3d743 | 1806 | middle_class = next_class; |
3003eba3 SR |
1807 | |
1808 | /* | |
1809 | * A direct locking problem where unsafe_class lock is taken | |
1810 | * directly by safe_class lock, then all we need to show | |
1811 | * is the deadlock scenario, as it is obvious that the | |
1812 | * unsafe lock is taken under the safe lock. | |
1813 | * | |
1814 | * But if there is a chain instead, where the safe lock takes | |
1815 | * an intermediate lock (middle_class) where this lock is | |
1816 | * not the same as the safe lock, then the lock chain is | |
1817 | * used to describe the problem. Otherwise we would need | |
1818 | * to show a different CPU case for each link in the chain | |
1819 | * from the safe_class lock to the unsafe_class lock. | |
1820 | */ | |
1821 | if (middle_class != unsafe_class) { | |
1822 | printk("Chain exists of:\n "); | |
1823 | __print_lock_name(safe_class); | |
f943fe0f | 1824 | printk(KERN_CONT " --> "); |
3003eba3 | 1825 | __print_lock_name(middle_class); |
f943fe0f | 1826 | printk(KERN_CONT " --> "); |
3003eba3 | 1827 | __print_lock_name(unsafe_class); |
f943fe0f | 1828 | printk(KERN_CONT "\n\n"); |
3003eba3 SR |
1829 | } |
1830 | ||
1831 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1832 | printk(" CPU0 CPU1\n"); | |
1833 | printk(" ---- ----\n"); | |
1834 | printk(" lock("); | |
1835 | __print_lock_name(unsafe_class); | |
f943fe0f | 1836 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1837 | printk(" local_irq_disable();\n"); |
1838 | printk(" lock("); | |
1839 | __print_lock_name(safe_class); | |
f943fe0f | 1840 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1841 | printk(" lock("); |
1842 | __print_lock_name(middle_class); | |
f943fe0f | 1843 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1844 | printk(" <Interrupt>\n"); |
1845 | printk(" lock("); | |
1846 | __print_lock_name(safe_class); | |
f943fe0f | 1847 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1848 | printk("\n *** DEADLOCK ***\n\n"); |
1849 | } | |
1850 | ||
fbb9ce95 IM |
1851 | static int |
1852 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1853 | struct lock_list *prev_root, |
1854 | struct lock_list *next_root, | |
1855 | struct lock_list *backwards_entry, | |
1856 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1857 | struct held_lock *prev, |
1858 | struct held_lock *next, | |
1859 | enum lock_usage_bit bit1, | |
1860 | enum lock_usage_bit bit2, | |
1861 | const char *irqclass) | |
1862 | { | |
74c383f1 | 1863 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1864 | return 0; |
1865 | ||
681fbec8 | 1866 | pr_warn("\n"); |
a5dd63ef PM |
1867 | pr_warn("=====================================================\n"); |
1868 | pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n", | |
fbb9ce95 | 1869 | irqclass, irqclass); |
fbdc4b9a | 1870 | print_kernel_ident(); |
a5dd63ef | 1871 | pr_warn("-----------------------------------------------------\n"); |
681fbec8 | 1872 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1873 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1874 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1875 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1876 | curr->hardirqs_enabled, | |
1877 | curr->softirqs_enabled); | |
1878 | print_lock(next); | |
1879 | ||
681fbec8 | 1880 | pr_warn("\nand this task is already holding:\n"); |
fbb9ce95 | 1881 | print_lock(prev); |
681fbec8 | 1882 | pr_warn("which would create a new lock dependency:\n"); |
f82b217e | 1883 | print_lock_name(hlock_class(prev)); |
681fbec8 | 1884 | pr_cont(" ->"); |
f82b217e | 1885 | print_lock_name(hlock_class(next)); |
681fbec8 | 1886 | pr_cont("\n"); |
fbb9ce95 | 1887 | |
681fbec8 | 1888 | pr_warn("\nbut this new dependency connects a %s-irq-safe lock:\n", |
fbb9ce95 | 1889 | irqclass); |
24208ca7 | 1890 | print_lock_name(backwards_entry->class); |
681fbec8 | 1891 | pr_warn("\n... which became %s-irq-safe at:\n", irqclass); |
fbb9ce95 | 1892 | |
c120bce7 | 1893 | print_lock_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 | 1894 | |
681fbec8 | 1895 | pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass); |
24208ca7 | 1896 | print_lock_name(forwards_entry->class); |
681fbec8 PM |
1897 | pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass); |
1898 | pr_warn("..."); | |
fbb9ce95 | 1899 | |
c120bce7 | 1900 | print_lock_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 | 1901 | |
681fbec8 | 1902 | pr_warn("\nother info that might help us debug this:\n\n"); |
dad3d743 SR |
1903 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1904 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1905 | |
fbb9ce95 IM |
1906 | lockdep_print_held_locks(curr); |
1907 | ||
681fbec8 | 1908 | pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass); |
24208ca7 ML |
1909 | if (!save_trace(&prev_root->trace)) |
1910 | return 0; | |
1911 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1912 | |
681fbec8 PM |
1913 | pr_warn("\nthe dependencies between the lock to be acquired"); |
1914 | pr_warn(" and %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 ML |
1915 | if (!save_trace(&next_root->trace)) |
1916 | return 0; | |
1917 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 | 1918 | |
681fbec8 | 1919 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
1920 | dump_stack(); |
1921 | ||
1922 | return 0; | |
1923 | } | |
1924 | ||
4f367d8a PZ |
1925 | static const char *state_names[] = { |
1926 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1927 | __stringify(__STATE), |
4f367d8a PZ |
1928 | #include "lockdep_states.h" |
1929 | #undef LOCKDEP_STATE | |
1930 | }; | |
1931 | ||
1932 | static const char *state_rnames[] = { | |
1933 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1934 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1935 | #include "lockdep_states.h" |
1936 | #undef LOCKDEP_STATE | |
1937 | }; | |
1938 | ||
1939 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1940 | { |
c902a1e8 FW |
1941 | if (bit & LOCK_USAGE_READ_MASK) |
1942 | return state_rnames[bit >> LOCK_USAGE_DIR_MASK]; | |
1943 | else | |
1944 | return state_names[bit >> LOCK_USAGE_DIR_MASK]; | |
4f367d8a | 1945 | } |
8e18257d | 1946 | |
948f8376 FW |
1947 | /* |
1948 | * The bit number is encoded like: | |
1949 | * | |
1950 | * bit0: 0 exclusive, 1 read lock | |
1951 | * bit1: 0 used in irq, 1 irq enabled | |
1952 | * bit2-n: state | |
1953 | */ | |
4f367d8a PZ |
1954 | static int exclusive_bit(int new_bit) |
1955 | { | |
bba2a8f1 FW |
1956 | int state = new_bit & LOCK_USAGE_STATE_MASK; |
1957 | int dir = new_bit & LOCK_USAGE_DIR_MASK; | |
8e18257d PZ |
1958 | |
1959 | /* | |
4f367d8a | 1960 | * keep state, bit flip the direction and strip read. |
8e18257d | 1961 | */ |
bba2a8f1 | 1962 | return state | (dir ^ LOCK_USAGE_DIR_MASK); |
4f367d8a PZ |
1963 | } |
1964 | ||
948f8376 FW |
1965 | /* |
1966 | * Observe that when given a bitmask where each bitnr is encoded as above, a | |
1967 | * right shift of the mask transforms the individual bitnrs as -1 and | |
1968 | * conversely, a left shift transforms into +1 for the individual bitnrs. | |
1969 | * | |
1970 | * So for all bits whose number have LOCK_ENABLED_* set (bitnr1 == 1), we can | |
1971 | * create the mask with those bit numbers using LOCK_USED_IN_* (bitnr1 == 0) | |
1972 | * instead by subtracting the bit number by 2, or shifting the mask right by 2. | |
1973 | * | |
1974 | * Similarly, bitnr1 == 0 becomes bitnr1 == 1 by adding 2, or shifting left 2. | |
1975 | * | |
1976 | * So split the mask (note that LOCKF_ENABLED_IRQ_ALL|LOCKF_USED_IN_IRQ_ALL is | |
1977 | * all bits set) and recompose with bitnr1 flipped. | |
1978 | */ | |
1979 | static unsigned long invert_dir_mask(unsigned long mask) | |
1980 | { | |
1981 | unsigned long excl = 0; | |
1982 | ||
1983 | /* Invert dir */ | |
1984 | excl |= (mask & LOCKF_ENABLED_IRQ_ALL) >> LOCK_USAGE_DIR_MASK; | |
1985 | excl |= (mask & LOCKF_USED_IN_IRQ_ALL) << LOCK_USAGE_DIR_MASK; | |
1986 | ||
1987 | return excl; | |
1988 | } | |
1989 | ||
1990 | /* | |
1991 | * As above, we clear bitnr0 (LOCK_*_READ off) with bitmask ops. First, for all | |
1992 | * bits with bitnr0 set (LOCK_*_READ), add those with bitnr0 cleared (LOCK_*). | |
1993 | * And then mask out all bitnr0. | |
1994 | */ | |
1995 | static unsigned long exclusive_mask(unsigned long mask) | |
1996 | { | |
1997 | unsigned long excl = invert_dir_mask(mask); | |
1998 | ||
1999 | /* Strip read */ | |
2000 | excl |= (excl & LOCKF_IRQ_READ) >> LOCK_USAGE_READ_MASK; | |
2001 | excl &= ~LOCKF_IRQ_READ; | |
2002 | ||
2003 | return excl; | |
2004 | } | |
2005 | ||
2006 | /* | |
2007 | * Retrieve the _possible_ original mask to which @mask is | |
2008 | * exclusive. Ie: this is the opposite of exclusive_mask(). | |
2009 | * Note that 2 possible original bits can match an exclusive | |
2010 | * bit: one has LOCK_USAGE_READ_MASK set, the other has it | |
2011 | * cleared. So both are returned for each exclusive bit. | |
2012 | */ | |
2013 | static unsigned long original_mask(unsigned long mask) | |
2014 | { | |
2015 | unsigned long excl = invert_dir_mask(mask); | |
2016 | ||
2017 | /* Include read in existing usages */ | |
2018 | excl |= (excl & LOCKF_IRQ) << LOCK_USAGE_READ_MASK; | |
2019 | ||
2020 | return excl; | |
2021 | } | |
2022 | ||
2023 | /* | |
2024 | * Find the first pair of bit match between an original | |
2025 | * usage mask and an exclusive usage mask. | |
2026 | */ | |
2027 | static int find_exclusive_match(unsigned long mask, | |
2028 | unsigned long excl_mask, | |
2029 | enum lock_usage_bit *bitp, | |
2030 | enum lock_usage_bit *excl_bitp) | |
2031 | { | |
2032 | int bit, excl; | |
2033 | ||
2034 | for_each_set_bit(bit, &mask, LOCK_USED) { | |
2035 | excl = exclusive_bit(bit); | |
2036 | if (excl_mask & lock_flag(excl)) { | |
2037 | *bitp = bit; | |
2038 | *excl_bitp = excl; | |
2039 | return 0; | |
2040 | } | |
2041 | } | |
2042 | return -1; | |
2043 | } | |
2044 | ||
2045 | /* | |
2046 | * Prove that the new dependency does not connect a hardirq-safe(-read) | |
2047 | * lock with a hardirq-unsafe lock - to achieve this we search | |
2048 | * the backwards-subgraph starting at <prev>, and the | |
2049 | * forwards-subgraph starting at <next>: | |
2050 | */ | |
4f367d8a | 2051 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, |
948f8376 | 2052 | struct held_lock *next) |
4f367d8a | 2053 | { |
948f8376 FW |
2054 | unsigned long usage_mask = 0, forward_mask, backward_mask; |
2055 | enum lock_usage_bit forward_bit = 0, backward_bit = 0; | |
2056 | struct lock_list *uninitialized_var(target_entry1); | |
2057 | struct lock_list *uninitialized_var(target_entry); | |
2058 | struct lock_list this, that; | |
2059 | int ret; | |
2060 | ||
8e18257d | 2061 | /* |
948f8376 FW |
2062 | * Step 1: gather all hard/soft IRQs usages backward in an |
2063 | * accumulated usage mask. | |
8e18257d | 2064 | */ |
948f8376 FW |
2065 | this.parent = NULL; |
2066 | this.class = hlock_class(prev); | |
8e18257d | 2067 | |
948f8376 FW |
2068 | ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL); |
2069 | if (ret < 0) | |
2070 | return print_bfs_bug(ret); | |
8e18257d | 2071 | |
948f8376 FW |
2072 | usage_mask &= LOCKF_USED_IN_IRQ_ALL; |
2073 | if (!usage_mask) | |
2074 | return 1; | |
4f367d8a | 2075 | |
cf40bd16 | 2076 | /* |
948f8376 FW |
2077 | * Step 2: find exclusive uses forward that match the previous |
2078 | * backward accumulated mask. | |
cf40bd16 | 2079 | */ |
948f8376 | 2080 | forward_mask = exclusive_mask(usage_mask); |
cf40bd16 | 2081 | |
948f8376 FW |
2082 | that.parent = NULL; |
2083 | that.class = hlock_class(next); | |
4f367d8a | 2084 | |
948f8376 FW |
2085 | ret = find_usage_forwards(&that, forward_mask, &target_entry1); |
2086 | if (ret < 0) | |
2087 | return print_bfs_bug(ret); | |
2088 | if (ret == 1) | |
2089 | return ret; | |
cf40bd16 | 2090 | |
948f8376 FW |
2091 | /* |
2092 | * Step 3: we found a bad match! Now retrieve a lock from the backward | |
2093 | * list whose usage mask matches the exclusive usage mask from the | |
2094 | * lock found on the forward list. | |
2095 | */ | |
2096 | backward_mask = original_mask(target_entry1->class->usage_mask); | |
2097 | ||
2098 | ret = find_usage_backwards(&this, backward_mask, &target_entry); | |
2099 | if (ret < 0) | |
2100 | return print_bfs_bug(ret); | |
2101 | if (DEBUG_LOCKS_WARN_ON(ret == 1)) | |
2102 | return 1; | |
2103 | ||
2104 | /* | |
2105 | * Step 4: narrow down to a pair of incompatible usage bits | |
2106 | * and report it. | |
2107 | */ | |
2108 | ret = find_exclusive_match(target_entry->class->usage_mask, | |
2109 | target_entry1->class->usage_mask, | |
2110 | &backward_bit, &forward_bit); | |
2111 | if (DEBUG_LOCKS_WARN_ON(ret == -1)) | |
2112 | return 1; | |
2113 | ||
2114 | return print_bad_irq_dependency(curr, &this, &that, | |
2115 | target_entry, target_entry1, | |
2116 | prev, next, | |
2117 | backward_bit, forward_bit, | |
2118 | state_name(backward_bit)); | |
8e18257d PZ |
2119 | } |
2120 | ||
2121 | static void inc_chains(void) | |
2122 | { | |
2123 | if (current->hardirq_context) | |
2124 | nr_hardirq_chains++; | |
2125 | else { | |
2126 | if (current->softirq_context) | |
2127 | nr_softirq_chains++; | |
2128 | else | |
2129 | nr_process_chains++; | |
2130 | } | |
2131 | } | |
2132 | ||
2133 | #else | |
2134 | ||
948f8376 FW |
2135 | static inline int check_irq_usage(struct task_struct *curr, |
2136 | struct held_lock *prev, struct held_lock *next) | |
8e18257d PZ |
2137 | { |
2138 | return 1; | |
2139 | } | |
2140 | ||
2141 | static inline void inc_chains(void) | |
2142 | { | |
2143 | nr_process_chains++; | |
2144 | } | |
2145 | ||
fbb9ce95 IM |
2146 | #endif |
2147 | ||
48702ecf SR |
2148 | static void |
2149 | print_deadlock_scenario(struct held_lock *nxt, | |
2150 | struct held_lock *prv) | |
2151 | { | |
2152 | struct lock_class *next = hlock_class(nxt); | |
2153 | struct lock_class *prev = hlock_class(prv); | |
2154 | ||
2155 | printk(" Possible unsafe locking scenario:\n\n"); | |
2156 | printk(" CPU0\n"); | |
2157 | printk(" ----\n"); | |
2158 | printk(" lock("); | |
2159 | __print_lock_name(prev); | |
f943fe0f | 2160 | printk(KERN_CONT ");\n"); |
48702ecf SR |
2161 | printk(" lock("); |
2162 | __print_lock_name(next); | |
f943fe0f | 2163 | printk(KERN_CONT ");\n"); |
48702ecf SR |
2164 | printk("\n *** DEADLOCK ***\n\n"); |
2165 | printk(" May be due to missing lock nesting notation\n\n"); | |
2166 | } | |
2167 | ||
fbb9ce95 IM |
2168 | static int |
2169 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
2170 | struct held_lock *next) | |
2171 | { | |
74c383f1 | 2172 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2173 | return 0; |
2174 | ||
681fbec8 | 2175 | pr_warn("\n"); |
a5dd63ef PM |
2176 | pr_warn("============================================\n"); |
2177 | pr_warn("WARNING: possible recursive locking detected\n"); | |
fbdc4b9a | 2178 | print_kernel_ident(); |
a5dd63ef | 2179 | pr_warn("--------------------------------------------\n"); |
681fbec8 | 2180 | pr_warn("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 2181 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 2182 | print_lock(next); |
681fbec8 | 2183 | pr_warn("\nbut task is already holding lock:\n"); |
fbb9ce95 IM |
2184 | print_lock(prev); |
2185 | ||
681fbec8 | 2186 | pr_warn("\nother info that might help us debug this:\n"); |
48702ecf | 2187 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
2188 | lockdep_print_held_locks(curr); |
2189 | ||
681fbec8 | 2190 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
2191 | dump_stack(); |
2192 | ||
2193 | return 0; | |
2194 | } | |
2195 | ||
2196 | /* | |
2197 | * Check whether we are holding such a class already. | |
2198 | * | |
2199 | * (Note that this has to be done separately, because the graph cannot | |
2200 | * detect such classes of deadlocks.) | |
2201 | * | |
2202 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
2203 | */ | |
2204 | static int | |
2205 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
2206 | struct lockdep_map *next_instance, int read) | |
2207 | { | |
2208 | struct held_lock *prev; | |
7531e2f3 | 2209 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
2210 | int i; |
2211 | ||
2212 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2213 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
2214 | |
2215 | if (prev->instance == next->nest_lock) | |
2216 | nest = prev; | |
2217 | ||
f82b217e | 2218 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 2219 | continue; |
7531e2f3 | 2220 | |
fbb9ce95 IM |
2221 | /* |
2222 | * Allow read-after-read recursion of the same | |
6c9076ec | 2223 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 2224 | */ |
6c9076ec | 2225 | if ((read == 2) && prev->read) |
fbb9ce95 | 2226 | return 2; |
7531e2f3 PZ |
2227 | |
2228 | /* | |
2229 | * We're holding the nest_lock, which serializes this lock's | |
2230 | * nesting behaviour. | |
2231 | */ | |
2232 | if (nest) | |
2233 | return 2; | |
2234 | ||
fbb9ce95 IM |
2235 | return print_deadlock_bug(curr, prev, next); |
2236 | } | |
2237 | return 1; | |
2238 | } | |
2239 | ||
2240 | /* | |
2241 | * There was a chain-cache miss, and we are about to add a new dependency | |
2242 | * to a previous lock. We recursively validate the following rules: | |
2243 | * | |
2244 | * - would the adding of the <prev> -> <next> dependency create a | |
2245 | * circular dependency in the graph? [== circular deadlock] | |
2246 | * | |
2247 | * - does the new prev->next dependency connect any hardirq-safe lock | |
2248 | * (in the full backwards-subgraph starting at <prev>) with any | |
2249 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
2250 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
2251 | * | |
2252 | * - does the new prev->next dependency connect any softirq-safe lock | |
2253 | * (in the full backwards-subgraph starting at <prev>) with any | |
2254 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
2255 | * <next>)? [== illegal lock inversion with softirq contexts] | |
2256 | * | |
2257 | * any of these scenarios could lead to a deadlock. | |
2258 | * | |
2259 | * Then if all the validations pass, we add the forwards and backwards | |
2260 | * dependency. | |
2261 | */ | |
2262 | static int | |
2263 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
c120bce7 | 2264 | struct held_lock *next, int distance, struct lock_trace *trace) |
fbb9ce95 | 2265 | { |
8b405d5c | 2266 | struct lock_list *uninitialized_var(target_entry); |
fbb9ce95 | 2267 | struct lock_list *entry; |
db0002a3 | 2268 | struct lock_list this; |
8b405d5c | 2269 | int ret; |
fbb9ce95 | 2270 | |
a0b0fd53 BVA |
2271 | if (!hlock_class(prev)->key || !hlock_class(next)->key) { |
2272 | /* | |
2273 | * The warning statements below may trigger a use-after-free | |
2274 | * of the class name. It is better to trigger a use-after free | |
2275 | * and to have the class name most of the time instead of not | |
2276 | * having the class name available. | |
2277 | */ | |
2278 | WARN_ONCE(!debug_locks_silent && !hlock_class(prev)->key, | |
2279 | "Detected use-after-free of lock class %px/%s\n", | |
2280 | hlock_class(prev), | |
2281 | hlock_class(prev)->name); | |
2282 | WARN_ONCE(!debug_locks_silent && !hlock_class(next)->key, | |
2283 | "Detected use-after-free of lock class %px/%s\n", | |
2284 | hlock_class(next), | |
2285 | hlock_class(next)->name); | |
2286 | return 2; | |
2287 | } | |
2288 | ||
fbb9ce95 IM |
2289 | /* |
2290 | * Prove that the new <prev> -> <next> dependency would not | |
2291 | * create a circular dependency in the graph. (We do this by | |
2292 | * forward-recursing into the graph starting at <next>, and | |
2293 | * checking whether we can reach <prev>.) | |
2294 | * | |
2295 | * We are using global variables to control the recursion, to | |
2296 | * keep the stackframe size of the recursive functions low: | |
2297 | */ | |
db0002a3 ML |
2298 | this.class = hlock_class(next); |
2299 | this.parent = NULL; | |
2300 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
8b405d5c | 2301 | if (unlikely(!ret)) { |
c120bce7 | 2302 | if (!trace->nr_entries) { |
8b405d5c | 2303 | /* |
76b14436 TG |
2304 | * If save_trace fails here, the printing might |
2305 | * trigger a WARN but because of the !nr_entries it | |
2306 | * should not do bad things. | |
8b405d5c | 2307 | */ |
76b14436 | 2308 | save_trace(trace); |
8b405d5c | 2309 | } |
b1abe462 | 2310 | return print_circular_bug(&this, target_entry, next, prev); |
8b405d5c | 2311 | } |
db0002a3 ML |
2312 | else if (unlikely(ret < 0)) |
2313 | return print_bfs_bug(ret); | |
c94aa5ca | 2314 | |
948f8376 | 2315 | if (!check_irq_usage(curr, prev, next)) |
fbb9ce95 IM |
2316 | return 0; |
2317 | ||
fbb9ce95 IM |
2318 | /* |
2319 | * For recursive read-locks we do all the dependency checks, | |
2320 | * but we dont store read-triggered dependencies (only | |
2321 | * write-triggered dependencies). This ensures that only the | |
2322 | * write-side dependencies matter, and that if for example a | |
2323 | * write-lock never takes any other locks, then the reads are | |
2324 | * equivalent to a NOP. | |
2325 | */ | |
2326 | if (next->read == 2 || prev->read == 2) | |
2327 | return 1; | |
2328 | /* | |
2329 | * Is the <prev> -> <next> dependency already present? | |
2330 | * | |
2331 | * (this may occur even though this is a new chain: consider | |
2332 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
2333 | * chains - the second one will be new, but L1 already has | |
2334 | * L2 added to its dependency list, due to the first chain.) | |
2335 | */ | |
f82b217e DJ |
2336 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
2337 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
2338 | if (distance == 1) |
2339 | entry->distance = 1; | |
70911fdc | 2340 | return 1; |
068135e6 | 2341 | } |
fbb9ce95 IM |
2342 | } |
2343 | ||
ae813308 PZ |
2344 | /* |
2345 | * Is the <prev> -> <next> link redundant? | |
2346 | */ | |
2347 | this.class = hlock_class(prev); | |
2348 | this.parent = NULL; | |
2349 | ret = check_redundant(&this, hlock_class(next), &target_entry); | |
2350 | if (!ret) { | |
2351 | debug_atomic_inc(nr_redundant); | |
2352 | return 2; | |
2353 | } | |
2354 | if (ret < 0) | |
2355 | return print_bfs_bug(ret); | |
2356 | ||
2357 | ||
c120bce7 | 2358 | if (!trace->nr_entries && !save_trace(trace)) |
ce07a941 | 2359 | return 0; |
4726f2a6 | 2360 | |
fbb9ce95 IM |
2361 | /* |
2362 | * Ok, all validations passed, add the new lock | |
2363 | * to the previous lock's dependency list: | |
2364 | */ | |
86cffb80 | 2365 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
f82b217e | 2366 | &hlock_class(prev)->locks_after, |
ce07a941 | 2367 | next->acquire_ip, distance, trace); |
068135e6 | 2368 | |
fbb9ce95 IM |
2369 | if (!ret) |
2370 | return 0; | |
910b1b2e | 2371 | |
86cffb80 | 2372 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
f82b217e | 2373 | &hlock_class(next)->locks_before, |
ce07a941 | 2374 | next->acquire_ip, distance, trace); |
910b1b2e JP |
2375 | if (!ret) |
2376 | return 0; | |
fbb9ce95 | 2377 | |
70911fdc | 2378 | return 2; |
8e18257d | 2379 | } |
fbb9ce95 | 2380 | |
8e18257d PZ |
2381 | /* |
2382 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
2383 | * The ones that are relevant are (in increasing distance from curr): | |
2384 | * all consecutive trylock entries and the final non-trylock entry - or | |
2385 | * the end of this context's lock-chain - whichever comes first. | |
2386 | */ | |
2387 | static int | |
2388 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
2389 | { | |
c120bce7 | 2390 | struct lock_trace trace = { .nr_entries = 0 }; |
8e18257d PZ |
2391 | int depth = curr->lockdep_depth; |
2392 | struct held_lock *hlock; | |
d6d897ce | 2393 | |
fbb9ce95 | 2394 | /* |
8e18257d PZ |
2395 | * Debugging checks. |
2396 | * | |
2397 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 2398 | */ |
8e18257d PZ |
2399 | if (!depth) |
2400 | goto out_bug; | |
fbb9ce95 | 2401 | /* |
8e18257d PZ |
2402 | * At least two relevant locks must exist for this |
2403 | * to be a head: | |
fbb9ce95 | 2404 | */ |
8e18257d PZ |
2405 | if (curr->held_locks[depth].irq_context != |
2406 | curr->held_locks[depth-1].irq_context) | |
2407 | goto out_bug; | |
74c383f1 | 2408 | |
8e18257d PZ |
2409 | for (;;) { |
2410 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 2411 | hlock = curr->held_locks + depth - 1; |
e966eaee | 2412 | |
8e18257d | 2413 | /* |
e966eaee IM |
2414 | * Only non-recursive-read entries get new dependencies |
2415 | * added: | |
8e18257d | 2416 | */ |
e966eaee | 2417 | if (hlock->read != 2 && hlock->check) { |
76b14436 TG |
2418 | int ret = check_prev_add(curr, hlock, next, distance, |
2419 | &trace); | |
e966eaee IM |
2420 | if (!ret) |
2421 | return 0; | |
2422 | ||
ce07a941 | 2423 | /* |
e966eaee IM |
2424 | * Stop after the first non-trylock entry, |
2425 | * as non-trylock entries have added their | |
2426 | * own direct dependencies already, so this | |
2427 | * lock is connected to them indirectly: | |
ce07a941 | 2428 | */ |
e966eaee IM |
2429 | if (!hlock->trylock) |
2430 | break; | |
74c383f1 | 2431 | } |
e966eaee | 2432 | |
8e18257d PZ |
2433 | depth--; |
2434 | /* | |
2435 | * End of lock-stack? | |
2436 | */ | |
2437 | if (!depth) | |
2438 | break; | |
2439 | /* | |
2440 | * Stop the search if we cross into another context: | |
2441 | */ | |
2442 | if (curr->held_locks[depth].irq_context != | |
2443 | curr->held_locks[depth-1].irq_context) | |
2444 | break; | |
fbb9ce95 | 2445 | } |
8e18257d PZ |
2446 | return 1; |
2447 | out_bug: | |
2448 | if (!debug_locks_off_graph_unlock()) | |
2449 | return 0; | |
fbb9ce95 | 2450 | |
0119fee4 PZ |
2451 | /* |
2452 | * Clearly we all shouldn't be here, but since we made it we | |
2453 | * can reliable say we messed up our state. See the above two | |
2454 | * gotos for reasons why we could possibly end up here. | |
2455 | */ | |
8e18257d | 2456 | WARN_ON(1); |
fbb9ce95 | 2457 | |
8e18257d | 2458 | return 0; |
fbb9ce95 IM |
2459 | } |
2460 | ||
443cd507 | 2461 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
de4643a7 | 2462 | static DECLARE_BITMAP(lock_chains_in_use, MAX_LOCKDEP_CHAINS); |
cd1a28e8 | 2463 | int nr_chain_hlocks; |
443cd507 HY |
2464 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
2465 | ||
2466 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
2467 | { | |
2468 | return lock_classes + chain_hlocks[chain->base + i]; | |
2469 | } | |
8e18257d | 2470 | |
9e4e7554 IM |
2471 | /* |
2472 | * Returns the index of the first held_lock of the current chain | |
2473 | */ | |
2474 | static inline int get_first_held_lock(struct task_struct *curr, | |
2475 | struct held_lock *hlock) | |
2476 | { | |
2477 | int i; | |
2478 | struct held_lock *hlock_curr; | |
2479 | ||
2480 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2481 | hlock_curr = curr->held_locks + i; | |
2482 | if (hlock_curr->irq_context != hlock->irq_context) | |
2483 | break; | |
2484 | ||
2485 | } | |
2486 | ||
2487 | return ++i; | |
2488 | } | |
2489 | ||
5c8a010c | 2490 | #ifdef CONFIG_DEBUG_LOCKDEP |
39e2e173 AAF |
2491 | /* |
2492 | * Returns the next chain_key iteration | |
2493 | */ | |
2494 | static u64 print_chain_key_iteration(int class_idx, u64 chain_key) | |
2495 | { | |
2496 | u64 new_chain_key = iterate_chain_key(chain_key, class_idx); | |
2497 | ||
2498 | printk(" class_idx:%d -> chain_key:%016Lx", | |
2499 | class_idx, | |
2500 | (unsigned long long)new_chain_key); | |
2501 | return new_chain_key; | |
2502 | } | |
2503 | ||
2504 | static void | |
2505 | print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) | |
2506 | { | |
2507 | struct held_lock *hlock; | |
2508 | u64 chain_key = 0; | |
2509 | int depth = curr->lockdep_depth; | |
2510 | int i; | |
2511 | ||
2512 | printk("depth: %u\n", depth + 1); | |
2513 | for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { | |
2514 | hlock = curr->held_locks + i; | |
2515 | chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); | |
2516 | ||
2517 | print_lock(hlock); | |
2518 | } | |
2519 | ||
2520 | print_chain_key_iteration(hlock_next->class_idx, chain_key); | |
2521 | print_lock(hlock_next); | |
2522 | } | |
2523 | ||
2524 | static void print_chain_keys_chain(struct lock_chain *chain) | |
2525 | { | |
2526 | int i; | |
2527 | u64 chain_key = 0; | |
2528 | int class_id; | |
2529 | ||
2530 | printk("depth: %u\n", chain->depth); | |
2531 | for (i = 0; i < chain->depth; i++) { | |
2532 | class_id = chain_hlocks[chain->base + i]; | |
2533 | chain_key = print_chain_key_iteration(class_id + 1, chain_key); | |
2534 | ||
2535 | print_lock_name(lock_classes + class_id); | |
2536 | printk("\n"); | |
2537 | } | |
2538 | } | |
2539 | ||
2540 | static void print_collision(struct task_struct *curr, | |
2541 | struct held_lock *hlock_next, | |
2542 | struct lock_chain *chain) | |
2543 | { | |
681fbec8 | 2544 | pr_warn("\n"); |
a5dd63ef PM |
2545 | pr_warn("============================\n"); |
2546 | pr_warn("WARNING: chain_key collision\n"); | |
39e2e173 | 2547 | print_kernel_ident(); |
a5dd63ef | 2548 | pr_warn("----------------------------\n"); |
681fbec8 PM |
2549 | pr_warn("%s/%d: ", current->comm, task_pid_nr(current)); |
2550 | pr_warn("Hash chain already cached but the contents don't match!\n"); | |
39e2e173 | 2551 | |
681fbec8 | 2552 | pr_warn("Held locks:"); |
39e2e173 AAF |
2553 | print_chain_keys_held_locks(curr, hlock_next); |
2554 | ||
681fbec8 | 2555 | pr_warn("Locks in cached chain:"); |
39e2e173 AAF |
2556 | print_chain_keys_chain(chain); |
2557 | ||
681fbec8 | 2558 | pr_warn("\nstack backtrace:\n"); |
39e2e173 AAF |
2559 | dump_stack(); |
2560 | } | |
5c8a010c | 2561 | #endif |
39e2e173 | 2562 | |
9e4e7554 IM |
2563 | /* |
2564 | * Checks whether the chain and the current held locks are consistent | |
2565 | * in depth and also in content. If they are not it most likely means | |
2566 | * that there was a collision during the calculation of the chain_key. | |
2567 | * Returns: 0 not passed, 1 passed | |
2568 | */ | |
2569 | static int check_no_collision(struct task_struct *curr, | |
2570 | struct held_lock *hlock, | |
2571 | struct lock_chain *chain) | |
2572 | { | |
2573 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2574 | int i, j, id; | |
2575 | ||
2576 | i = get_first_held_lock(curr, hlock); | |
2577 | ||
39e2e173 AAF |
2578 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { |
2579 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2580 | return 0; |
39e2e173 | 2581 | } |
9e4e7554 IM |
2582 | |
2583 | for (j = 0; j < chain->depth - 1; j++, i++) { | |
2584 | id = curr->held_locks[i].class_idx - 1; | |
2585 | ||
39e2e173 AAF |
2586 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { |
2587 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2588 | return 0; |
39e2e173 | 2589 | } |
9e4e7554 IM |
2590 | } |
2591 | #endif | |
2592 | return 1; | |
2593 | } | |
2594 | ||
2212684a BVA |
2595 | /* |
2596 | * Given an index that is >= -1, return the index of the next lock chain. | |
2597 | * Return -2 if there is no next lock chain. | |
2598 | */ | |
2599 | long lockdep_next_lockchain(long i) | |
2600 | { | |
de4643a7 BVA |
2601 | i = find_next_bit(lock_chains_in_use, ARRAY_SIZE(lock_chains), i + 1); |
2602 | return i < ARRAY_SIZE(lock_chains) ? i : -2; | |
2212684a BVA |
2603 | } |
2604 | ||
2605 | unsigned long lock_chain_count(void) | |
2606 | { | |
de4643a7 BVA |
2607 | return bitmap_weight(lock_chains_in_use, ARRAY_SIZE(lock_chains)); |
2608 | } | |
2609 | ||
2610 | /* Must be called with the graph lock held. */ | |
2611 | static struct lock_chain *alloc_lock_chain(void) | |
2612 | { | |
2613 | int idx = find_first_zero_bit(lock_chains_in_use, | |
2614 | ARRAY_SIZE(lock_chains)); | |
2615 | ||
2616 | if (unlikely(idx >= ARRAY_SIZE(lock_chains))) | |
2617 | return NULL; | |
2618 | __set_bit(idx, lock_chains_in_use); | |
2619 | return lock_chains + idx; | |
2212684a BVA |
2620 | } |
2621 | ||
fbb9ce95 | 2622 | /* |
545c23f2 BP |
2623 | * Adds a dependency chain into chain hashtable. And must be called with |
2624 | * graph_lock held. | |
2625 | * | |
2626 | * Return 0 if fail, and graph_lock is released. | |
2627 | * Return 1 if succeed, with graph_lock held. | |
fbb9ce95 | 2628 | */ |
545c23f2 BP |
2629 | static inline int add_chain_cache(struct task_struct *curr, |
2630 | struct held_lock *hlock, | |
2631 | u64 chain_key) | |
fbb9ce95 | 2632 | { |
f82b217e | 2633 | struct lock_class *class = hlock_class(hlock); |
a63f38cc | 2634 | struct hlist_head *hash_head = chainhashentry(chain_key); |
fbb9ce95 | 2635 | struct lock_chain *chain; |
e0944ee6 | 2636 | int i, j; |
fbb9ce95 | 2637 | |
0119fee4 | 2638 | /* |
527af3ea | 2639 | * The caller must hold the graph lock, ensure we've got IRQs |
0119fee4 PZ |
2640 | * disabled to make this an IRQ-safe lock.. for recursion reasons |
2641 | * lockdep won't complain about its own locking errors. | |
2642 | */ | |
381a2292 JP |
2643 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2644 | return 0; | |
9e4e7554 | 2645 | |
de4643a7 BVA |
2646 | chain = alloc_lock_chain(); |
2647 | if (!chain) { | |
74c383f1 IM |
2648 | if (!debug_locks_off_graph_unlock()) |
2649 | return 0; | |
2650 | ||
2c522836 | 2651 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2652 | dump_stack(); |
fbb9ce95 IM |
2653 | return 0; |
2654 | } | |
fbb9ce95 | 2655 | chain->chain_key = chain_key; |
443cd507 | 2656 | chain->irq_context = hlock->irq_context; |
9e4e7554 | 2657 | i = get_first_held_lock(curr, hlock); |
443cd507 | 2658 | chain->depth = curr->lockdep_depth + 1 - i; |
75dd602a PZ |
2659 | |
2660 | BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks)); | |
2661 | BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks)); | |
2662 | BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes)); | |
2663 | ||
e0944ee6 SR |
2664 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2665 | chain->base = nr_chain_hlocks; | |
443cd507 | 2666 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2667 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2668 | chain_hlocks[chain->base + j] = lock_id; |
2669 | } | |
2670 | chain_hlocks[chain->base + j] = class - lock_classes; | |
75dd602a | 2671 | nr_chain_hlocks += chain->depth; |
523b113b | 2672 | } else { |
f9af456a | 2673 | if (!debug_locks_off_graph_unlock()) |
75dd602a PZ |
2674 | return 0; |
2675 | ||
2676 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); | |
2677 | dump_stack(); | |
2678 | return 0; | |
2679 | } | |
75dd602a | 2680 | |
a63f38cc | 2681 | hlist_add_head_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2682 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2683 | inc_chains(); |
2684 | ||
2685 | return 1; | |
2686 | } | |
2687 | ||
545c23f2 | 2688 | /* |
a0b0fd53 BVA |
2689 | * Look up a dependency chain. Must be called with either the graph lock or |
2690 | * the RCU read lock held. | |
545c23f2 BP |
2691 | */ |
2692 | static inline struct lock_chain *lookup_chain_cache(u64 chain_key) | |
2693 | { | |
2694 | struct hlist_head *hash_head = chainhashentry(chain_key); | |
2695 | struct lock_chain *chain; | |
2696 | ||
545c23f2 | 2697 | hlist_for_each_entry_rcu(chain, hash_head, entry) { |
a0b0fd53 | 2698 | if (READ_ONCE(chain->chain_key) == chain_key) { |
545c23f2 BP |
2699 | debug_atomic_inc(chain_lookup_hits); |
2700 | return chain; | |
2701 | } | |
2702 | } | |
2703 | return NULL; | |
2704 | } | |
2705 | ||
2706 | /* | |
2707 | * If the key is not present yet in dependency chain cache then | |
2708 | * add it and return 1 - in this case the new dependency chain is | |
2709 | * validated. If the key is already hashed, return 0. | |
2710 | * (On return with 1 graph_lock is held.) | |
2711 | */ | |
2712 | static inline int lookup_chain_cache_add(struct task_struct *curr, | |
2713 | struct held_lock *hlock, | |
2714 | u64 chain_key) | |
2715 | { | |
2716 | struct lock_class *class = hlock_class(hlock); | |
2717 | struct lock_chain *chain = lookup_chain_cache(chain_key); | |
2718 | ||
2719 | if (chain) { | |
2720 | cache_hit: | |
2721 | if (!check_no_collision(curr, hlock, chain)) | |
2722 | return 0; | |
2723 | ||
2724 | if (very_verbose(class)) { | |
2725 | printk("\nhash chain already cached, key: " | |
04860d48 | 2726 | "%016Lx tail class: [%px] %s\n", |
545c23f2 BP |
2727 | (unsigned long long)chain_key, |
2728 | class->key, class->name); | |
2729 | } | |
2730 | ||
2731 | return 0; | |
2732 | } | |
2733 | ||
2734 | if (very_verbose(class)) { | |
04860d48 | 2735 | printk("\nnew hash chain, key: %016Lx tail class: [%px] %s\n", |
545c23f2 BP |
2736 | (unsigned long long)chain_key, class->key, class->name); |
2737 | } | |
2738 | ||
2739 | if (!graph_lock()) | |
2740 | return 0; | |
2741 | ||
2742 | /* | |
2743 | * We have to walk the chain again locked - to avoid duplicates: | |
2744 | */ | |
2745 | chain = lookup_chain_cache(chain_key); | |
2746 | if (chain) { | |
2747 | graph_unlock(); | |
2748 | goto cache_hit; | |
2749 | } | |
2750 | ||
2751 | if (!add_chain_cache(curr, hlock, chain_key)) | |
2752 | return 0; | |
2753 | ||
2754 | return 1; | |
2755 | } | |
2756 | ||
8e18257d | 2757 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, |
4e6045f1 | 2758 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2759 | { |
2760 | /* | |
2761 | * Trylock needs to maintain the stack of held locks, but it | |
2762 | * does not add new dependencies, because trylock can be done | |
2763 | * in any order. | |
2764 | * | |
2765 | * We look up the chain_key and do the O(N^2) check and update of | |
2766 | * the dependencies only if this is a new dependency chain. | |
545c23f2 | 2767 | * (If lookup_chain_cache_add() return with 1 it acquires |
8e18257d PZ |
2768 | * graph_lock for us) |
2769 | */ | |
fb9edbe9 | 2770 | if (!hlock->trylock && hlock->check && |
545c23f2 | 2771 | lookup_chain_cache_add(curr, hlock, chain_key)) { |
8e18257d PZ |
2772 | /* |
2773 | * Check whether last held lock: | |
2774 | * | |
2775 | * - is irq-safe, if this lock is irq-unsafe | |
2776 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2777 | * | |
2778 | * And check whether the new lock's dependency graph | |
2779 | * could lead back to the previous lock. | |
2780 | * | |
2781 | * any of these scenarios could lead to a deadlock. If | |
2782 | * All validations | |
2783 | */ | |
2784 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2785 | ||
2786 | if (!ret) | |
2787 | return 0; | |
2788 | /* | |
2789 | * Mark recursive read, as we jump over it when | |
2790 | * building dependencies (just like we jump over | |
2791 | * trylock entries): | |
2792 | */ | |
2793 | if (ret == 2) | |
2794 | hlock->read = 2; | |
2795 | /* | |
2796 | * Add dependency only if this lock is not the head | |
2797 | * of the chain, and if it's not a secondary read-lock: | |
2798 | */ | |
545c23f2 | 2799 | if (!chain_head && ret != 2) { |
8e18257d PZ |
2800 | if (!check_prevs_add(curr, hlock)) |
2801 | return 0; | |
545c23f2 BP |
2802 | } |
2803 | ||
8e18257d | 2804 | graph_unlock(); |
545c23f2 BP |
2805 | } else { |
2806 | /* after lookup_chain_cache_add(): */ | |
8e18257d PZ |
2807 | if (unlikely(!debug_locks)) |
2808 | return 0; | |
545c23f2 | 2809 | } |
fbb9ce95 IM |
2810 | |
2811 | return 1; | |
2812 | } | |
8e18257d PZ |
2813 | #else |
2814 | static inline int validate_chain(struct task_struct *curr, | |
2815 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2816 | int chain_head, u64 chain_key) |
8e18257d PZ |
2817 | { |
2818 | return 1; | |
2819 | } | |
c120bce7 TG |
2820 | |
2821 | static void print_lock_trace(struct lock_trace *trace, unsigned int spaces) | |
2822 | { | |
2823 | } | |
ca58abcb | 2824 | #endif |
fbb9ce95 IM |
2825 | |
2826 | /* | |
2827 | * We are building curr_chain_key incrementally, so double-check | |
2828 | * it from scratch, to make sure that it's done correctly: | |
2829 | */ | |
1d09daa5 | 2830 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2831 | { |
2832 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2833 | struct held_lock *hlock, *prev_hlock = NULL; | |
5f18ab5c | 2834 | unsigned int i; |
fbb9ce95 IM |
2835 | u64 chain_key = 0; |
2836 | ||
2837 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2838 | hlock = curr->held_locks + i; | |
2839 | if (chain_key != hlock->prev_chain_key) { | |
2840 | debug_locks_off(); | |
0119fee4 PZ |
2841 | /* |
2842 | * We got mighty confused, our chain keys don't match | |
2843 | * with what we expect, someone trample on our task state? | |
2844 | */ | |
2df8b1d6 | 2845 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2846 | curr->lockdep_depth, i, |
2847 | (unsigned long long)chain_key, | |
2848 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2849 | return; |
2850 | } | |
0119fee4 PZ |
2851 | /* |
2852 | * Whoops ran out of static storage again? | |
2853 | */ | |
5f18ab5c | 2854 | if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) |
381a2292 JP |
2855 | return; |
2856 | ||
fbb9ce95 IM |
2857 | if (prev_hlock && (prev_hlock->irq_context != |
2858 | hlock->irq_context)) | |
2859 | chain_key = 0; | |
5f18ab5c | 2860 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
fbb9ce95 IM |
2861 | prev_hlock = hlock; |
2862 | } | |
2863 | if (chain_key != curr->curr_chain_key) { | |
2864 | debug_locks_off(); | |
0119fee4 PZ |
2865 | /* |
2866 | * More smoking hash instead of calculating it, damn see these | |
2867 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2868 | */ | |
2df8b1d6 | 2869 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2870 | curr->lockdep_depth, i, |
2871 | (unsigned long long)chain_key, | |
2872 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2873 | } |
2874 | #endif | |
2875 | } | |
2876 | ||
0d2cc3b3 FW |
2877 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
2878 | enum lock_usage_bit new_bit); | |
2879 | ||
2880 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) | |
2881 | ||
2882 | ||
282b5c2f SR |
2883 | static void |
2884 | print_usage_bug_scenario(struct held_lock *lock) | |
2885 | { | |
2886 | struct lock_class *class = hlock_class(lock); | |
2887 | ||
2888 | printk(" Possible unsafe locking scenario:\n\n"); | |
2889 | printk(" CPU0\n"); | |
2890 | printk(" ----\n"); | |
2891 | printk(" lock("); | |
2892 | __print_lock_name(class); | |
f943fe0f | 2893 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2894 | printk(" <Interrupt>\n"); |
2895 | printk(" lock("); | |
2896 | __print_lock_name(class); | |
f943fe0f | 2897 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2898 | printk("\n *** DEADLOCK ***\n\n"); |
2899 | } | |
2900 | ||
8e18257d PZ |
2901 | static int |
2902 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2903 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2904 | { | |
2905 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2906 | return 0; | |
2907 | ||
681fbec8 | 2908 | pr_warn("\n"); |
a5dd63ef PM |
2909 | pr_warn("================================\n"); |
2910 | pr_warn("WARNING: inconsistent lock state\n"); | |
fbdc4b9a | 2911 | print_kernel_ident(); |
a5dd63ef | 2912 | pr_warn("--------------------------------\n"); |
8e18257d | 2913 | |
681fbec8 | 2914 | pr_warn("inconsistent {%s} -> {%s} usage.\n", |
8e18257d PZ |
2915 | usage_str[prev_bit], usage_str[new_bit]); |
2916 | ||
681fbec8 | 2917 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", |
ba25f9dc | 2918 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2919 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2920 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2921 | trace_hardirqs_enabled(curr), | |
2922 | trace_softirqs_enabled(curr)); | |
2923 | print_lock(this); | |
2924 | ||
681fbec8 | 2925 | pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]); |
c120bce7 | 2926 | print_lock_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2927 | |
2928 | print_irqtrace_events(curr); | |
681fbec8 | 2929 | pr_warn("\nother info that might help us debug this:\n"); |
282b5c2f SR |
2930 | print_usage_bug_scenario(this); |
2931 | ||
8e18257d PZ |
2932 | lockdep_print_held_locks(curr); |
2933 | ||
681fbec8 | 2934 | pr_warn("\nstack backtrace:\n"); |
8e18257d PZ |
2935 | dump_stack(); |
2936 | ||
2937 | return 0; | |
2938 | } | |
2939 | ||
2940 | /* | |
2941 | * Print out an error if an invalid bit is set: | |
2942 | */ | |
2943 | static inline int | |
2944 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2945 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2946 | { | |
f82b217e | 2947 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2948 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2949 | return 1; | |
2950 | } | |
2951 | ||
fbb9ce95 IM |
2952 | |
2953 | /* | |
2954 | * print irq inversion bug: | |
2955 | */ | |
2956 | static int | |
24208ca7 ML |
2957 | print_irq_inversion_bug(struct task_struct *curr, |
2958 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2959 | struct held_lock *this, int forwards, |
2960 | const char *irqclass) | |
2961 | { | |
dad3d743 SR |
2962 | struct lock_list *entry = other; |
2963 | struct lock_list *middle = NULL; | |
2964 | int depth; | |
2965 | ||
74c383f1 | 2966 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2967 | return 0; |
2968 | ||
681fbec8 | 2969 | pr_warn("\n"); |
a5dd63ef PM |
2970 | pr_warn("========================================================\n"); |
2971 | pr_warn("WARNING: possible irq lock inversion dependency detected\n"); | |
fbdc4b9a | 2972 | print_kernel_ident(); |
a5dd63ef | 2973 | pr_warn("--------------------------------------------------------\n"); |
681fbec8 | 2974 | pr_warn("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2975 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2976 | print_lock(this); |
2977 | if (forwards) | |
681fbec8 | 2978 | pr_warn("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2979 | else |
681fbec8 | 2980 | pr_warn("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2981 | print_lock_name(other->class); |
681fbec8 | 2982 | pr_warn("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
fbb9ce95 | 2983 | |
681fbec8 | 2984 | pr_warn("\nother info that might help us debug this:\n"); |
dad3d743 SR |
2985 | |
2986 | /* Find a middle lock (if one exists) */ | |
2987 | depth = get_lock_depth(other); | |
2988 | do { | |
2989 | if (depth == 0 && (entry != root)) { | |
681fbec8 | 2990 | pr_warn("lockdep:%s bad path found in chain graph\n", __func__); |
dad3d743 SR |
2991 | break; |
2992 | } | |
2993 | middle = entry; | |
2994 | entry = get_lock_parent(entry); | |
2995 | depth--; | |
2996 | } while (entry && entry != root && (depth >= 0)); | |
2997 | if (forwards) | |
2998 | print_irq_lock_scenario(root, other, | |
2999 | middle ? middle->class : root->class, other->class); | |
3000 | else | |
3001 | print_irq_lock_scenario(other, root, | |
3002 | middle ? middle->class : other->class, root->class); | |
3003 | ||
fbb9ce95 IM |
3004 | lockdep_print_held_locks(curr); |
3005 | ||
681fbec8 | 3006 | pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
24208ca7 ML |
3007 | if (!save_trace(&root->trace)) |
3008 | return 0; | |
3009 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 | 3010 | |
681fbec8 | 3011 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
3012 | dump_stack(); |
3013 | ||
3014 | return 0; | |
3015 | } | |
3016 | ||
3017 | /* | |
3018 | * Prove that in the forwards-direction subgraph starting at <this> | |
3019 | * there is no lock matching <mask>: | |
3020 | */ | |
3021 | static int | |
3022 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
3023 | enum lock_usage_bit bit, const char *irqclass) | |
3024 | { | |
3025 | int ret; | |
d7aaba14 ML |
3026 | struct lock_list root; |
3027 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 3028 | |
d7aaba14 ML |
3029 | root.parent = NULL; |
3030 | root.class = hlock_class(this); | |
627f364d | 3031 | ret = find_usage_forwards(&root, lock_flag(bit), &target_entry); |
af012961 PZ |
3032 | if (ret < 0) |
3033 | return print_bfs_bug(ret); | |
3034 | if (ret == 1) | |
3035 | return ret; | |
fbb9ce95 | 3036 | |
24208ca7 | 3037 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 3038 | this, 1, irqclass); |
fbb9ce95 IM |
3039 | } |
3040 | ||
3041 | /* | |
3042 | * Prove that in the backwards-direction subgraph starting at <this> | |
3043 | * there is no lock matching <mask>: | |
3044 | */ | |
3045 | static int | |
3046 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
3047 | enum lock_usage_bit bit, const char *irqclass) | |
3048 | { | |
3049 | int ret; | |
d7aaba14 ML |
3050 | struct lock_list root; |
3051 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 3052 | |
d7aaba14 ML |
3053 | root.parent = NULL; |
3054 | root.class = hlock_class(this); | |
627f364d | 3055 | ret = find_usage_backwards(&root, lock_flag(bit), &target_entry); |
af012961 PZ |
3056 | if (ret < 0) |
3057 | return print_bfs_bug(ret); | |
3058 | if (ret == 1) | |
3059 | return ret; | |
fbb9ce95 | 3060 | |
24208ca7 | 3061 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 3062 | this, 0, irqclass); |
fbb9ce95 IM |
3063 | } |
3064 | ||
3117df04 | 3065 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
3066 | { |
3067 | printk("irq event stamp: %u\n", curr->irq_events); | |
04860d48 | 3068 | printk("hardirqs last enabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3069 | curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip, |
3070 | (void *)curr->hardirq_enable_ip); | |
04860d48 | 3071 | printk("hardirqs last disabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3072 | curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip, |
3073 | (void *)curr->hardirq_disable_ip); | |
04860d48 | 3074 | printk("softirqs last enabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3075 | curr->softirq_enable_event, (void *)curr->softirq_enable_ip, |
3076 | (void *)curr->softirq_enable_ip); | |
04860d48 | 3077 | printk("softirqs last disabled at (%u): [<%px>] %pS\n", |
f943fe0f DV |
3078 | curr->softirq_disable_event, (void *)curr->softirq_disable_ip, |
3079 | (void *)curr->softirq_disable_ip); | |
fbb9ce95 IM |
3080 | } |
3081 | ||
cd95302d | 3082 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 3083 | { |
8e18257d PZ |
3084 | #if HARDIRQ_VERBOSE |
3085 | return class_filter(class); | |
3086 | #endif | |
fbb9ce95 IM |
3087 | return 0; |
3088 | } | |
3089 | ||
cd95302d | 3090 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 3091 | { |
8e18257d PZ |
3092 | #if SOFTIRQ_VERBOSE |
3093 | return class_filter(class); | |
3094 | #endif | |
3095 | return 0; | |
fbb9ce95 IM |
3096 | } |
3097 | ||
3098 | #define STRICT_READ_CHECKS 1 | |
3099 | ||
cd95302d PZ |
3100 | static int (*state_verbose_f[])(struct lock_class *class) = { |
3101 | #define LOCKDEP_STATE(__STATE) \ | |
3102 | __STATE##_verbose, | |
3103 | #include "lockdep_states.h" | |
3104 | #undef LOCKDEP_STATE | |
3105 | }; | |
3106 | ||
3107 | static inline int state_verbose(enum lock_usage_bit bit, | |
3108 | struct lock_class *class) | |
3109 | { | |
c902a1e8 | 3110 | return state_verbose_f[bit >> LOCK_USAGE_DIR_MASK](class); |
cd95302d PZ |
3111 | } |
3112 | ||
42c50d54 PZ |
3113 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
3114 | enum lock_usage_bit bit, const char *name); | |
3115 | ||
6a6904d3 | 3116 | static int |
1c21f14e PZ |
3117 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
3118 | enum lock_usage_bit new_bit) | |
6a6904d3 | 3119 | { |
f989209e | 3120 | int excl_bit = exclusive_bit(new_bit); |
bba2a8f1 FW |
3121 | int read = new_bit & LOCK_USAGE_READ_MASK; |
3122 | int dir = new_bit & LOCK_USAGE_DIR_MASK; | |
42c50d54 | 3123 | |
38aa2714 PZ |
3124 | /* |
3125 | * mark USED_IN has to look forwards -- to ensure no dependency | |
3126 | * has ENABLED state, which would allow recursion deadlocks. | |
3127 | * | |
3128 | * mark ENABLED has to look backwards -- to ensure no dependee | |
3129 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
3130 | */ | |
42c50d54 PZ |
3131 | check_usage_f usage = dir ? |
3132 | check_usage_backwards : check_usage_forwards; | |
f989209e | 3133 | |
38aa2714 PZ |
3134 | /* |
3135 | * Validate that this particular lock does not have conflicting | |
3136 | * usage states. | |
3137 | */ | |
6a6904d3 PZ |
3138 | if (!valid_state(curr, this, new_bit, excl_bit)) |
3139 | return 0; | |
42c50d54 | 3140 | |
38aa2714 PZ |
3141 | /* |
3142 | * Validate that the lock dependencies don't have conflicting usage | |
3143 | * states. | |
3144 | */ | |
3145 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
bba2a8f1 | 3146 | !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK))) |
6a6904d3 | 3147 | return 0; |
780e820b | 3148 | |
38aa2714 PZ |
3149 | /* |
3150 | * Check for read in write conflicts | |
3151 | */ | |
3152 | if (!read) { | |
bba2a8f1 | 3153 | if (!valid_state(curr, this, new_bit, excl_bit + LOCK_USAGE_READ_MASK)) |
38aa2714 PZ |
3154 | return 0; |
3155 | ||
3156 | if (STRICT_READ_CHECKS && | |
bba2a8f1 FW |
3157 | !usage(curr, this, excl_bit + LOCK_USAGE_READ_MASK, |
3158 | state_name(new_bit + LOCK_USAGE_READ_MASK))) | |
38aa2714 PZ |
3159 | return 0; |
3160 | } | |
780e820b | 3161 | |
cd95302d | 3162 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
3163 | return 2; |
3164 | ||
3165 | return 1; | |
3166 | } | |
3167 | ||
fbb9ce95 IM |
3168 | /* |
3169 | * Mark all held locks with a usage bit: | |
3170 | */ | |
1d09daa5 | 3171 | static int |
436a49ae | 3172 | mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit) |
fbb9ce95 | 3173 | { |
fbb9ce95 IM |
3174 | struct held_lock *hlock; |
3175 | int i; | |
3176 | ||
3177 | for (i = 0; i < curr->lockdep_depth; i++) { | |
436a49ae | 3178 | enum lock_usage_bit hlock_bit = base_bit; |
fbb9ce95 IM |
3179 | hlock = curr->held_locks + i; |
3180 | ||
cf2ad4d1 | 3181 | if (hlock->read) |
bba2a8f1 | 3182 | hlock_bit += LOCK_USAGE_READ_MASK; |
cf2ad4d1 | 3183 | |
436a49ae | 3184 | BUG_ON(hlock_bit >= LOCK_USAGE_STATES); |
cf40bd16 | 3185 | |
34d0ed5e | 3186 | if (!hlock->check) |
efbe2eee PZ |
3187 | continue; |
3188 | ||
436a49ae | 3189 | if (!mark_lock(curr, hlock, hlock_bit)) |
fbb9ce95 IM |
3190 | return 0; |
3191 | } | |
3192 | ||
3193 | return 1; | |
3194 | } | |
3195 | ||
fbb9ce95 IM |
3196 | /* |
3197 | * Hardirqs will be enabled: | |
3198 | */ | |
dd4e5d3a | 3199 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
3200 | { |
3201 | struct task_struct *curr = current; | |
fbb9ce95 | 3202 | |
fbb9ce95 IM |
3203 | /* we'll do an OFF -> ON transition: */ |
3204 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 3205 | |
fbb9ce95 IM |
3206 | /* |
3207 | * We are going to turn hardirqs on, so set the | |
3208 | * usage bit for all held locks: | |
3209 | */ | |
436a49ae | 3210 | if (!mark_held_locks(curr, LOCK_ENABLED_HARDIRQ)) |
fbb9ce95 IM |
3211 | return; |
3212 | /* | |
3213 | * If we have softirqs enabled, then set the usage | |
3214 | * bit for all held locks. (disabled hardirqs prevented | |
3215 | * this bit from being set before) | |
3216 | */ | |
3217 | if (curr->softirqs_enabled) | |
436a49ae | 3218 | if (!mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ)) |
fbb9ce95 IM |
3219 | return; |
3220 | ||
8e18257d PZ |
3221 | curr->hardirq_enable_ip = ip; |
3222 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 3223 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 3224 | } |
dd4e5d3a | 3225 | |
bff1b208 | 3226 | void lockdep_hardirqs_on(unsigned long ip) |
dd4e5d3a | 3227 | { |
dd4e5d3a PZ |
3228 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
3229 | return; | |
3230 | ||
7d36b26b PZ |
3231 | if (unlikely(current->hardirqs_enabled)) { |
3232 | /* | |
3233 | * Neither irq nor preemption are disabled here | |
3234 | * so this is racy by nature but losing one hit | |
3235 | * in a stat is not a big deal. | |
3236 | */ | |
3237 | __debug_atomic_inc(redundant_hardirqs_on); | |
3238 | return; | |
3239 | } | |
3240 | ||
0119fee4 PZ |
3241 | /* |
3242 | * We're enabling irqs and according to our state above irqs weren't | |
3243 | * already enabled, yet we find the hardware thinks they are in fact | |
3244 | * enabled.. someone messed up their IRQ state tracing. | |
3245 | */ | |
dd4e5d3a PZ |
3246 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3247 | return; | |
3248 | ||
0119fee4 PZ |
3249 | /* |
3250 | * See the fine text that goes along with this variable definition. | |
3251 | */ | |
d671002b | 3252 | if (DEBUG_LOCKS_WARN_ON(early_boot_irqs_disabled)) |
7d36b26b PZ |
3253 | return; |
3254 | ||
0119fee4 PZ |
3255 | /* |
3256 | * Can't allow enabling interrupts while in an interrupt handler, | |
3257 | * that's general bad form and such. Recursion, limited stack etc.. | |
3258 | */ | |
7d36b26b PZ |
3259 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
3260 | return; | |
3261 | ||
dd4e5d3a PZ |
3262 | current->lockdep_recursion = 1; |
3263 | __trace_hardirqs_on_caller(ip); | |
3264 | current->lockdep_recursion = 0; | |
3265 | } | |
2f43c602 | 3266 | NOKPROBE_SYMBOL(lockdep_hardirqs_on); |
8e18257d PZ |
3267 | |
3268 | /* | |
3269 | * Hardirqs were disabled: | |
3270 | */ | |
bff1b208 | 3271 | void lockdep_hardirqs_off(unsigned long ip) |
8e18257d PZ |
3272 | { |
3273 | struct task_struct *curr = current; | |
3274 | ||
3275 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
3276 | return; | |
3277 | ||
0119fee4 PZ |
3278 | /* |
3279 | * So we're supposed to get called after you mask local IRQs, but for | |
3280 | * some reason the hardware doesn't quite think you did a proper job. | |
3281 | */ | |
8e18257d PZ |
3282 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3283 | return; | |
3284 | ||
3285 | if (curr->hardirqs_enabled) { | |
3286 | /* | |
3287 | * We have done an ON -> OFF transition: | |
3288 | */ | |
3289 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 3290 | curr->hardirq_disable_ip = ip; |
8e18257d | 3291 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 3292 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 3293 | } else |
bd6d29c2 | 3294 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 3295 | } |
2f43c602 | 3296 | NOKPROBE_SYMBOL(lockdep_hardirqs_off); |
8e18257d PZ |
3297 | |
3298 | /* | |
3299 | * Softirqs will be enabled: | |
3300 | */ | |
3301 | void trace_softirqs_on(unsigned long ip) | |
3302 | { | |
3303 | struct task_struct *curr = current; | |
3304 | ||
dd4e5d3a | 3305 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
3306 | return; |
3307 | ||
0119fee4 PZ |
3308 | /* |
3309 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
3310 | * funny state and nesting things. | |
3311 | */ | |
8e18257d PZ |
3312 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3313 | return; | |
3314 | ||
3315 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 3316 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
3317 | return; |
3318 | } | |
3319 | ||
dd4e5d3a | 3320 | current->lockdep_recursion = 1; |
8e18257d PZ |
3321 | /* |
3322 | * We'll do an OFF -> ON transition: | |
3323 | */ | |
3324 | curr->softirqs_enabled = 1; | |
3325 | curr->softirq_enable_ip = ip; | |
3326 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 3327 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
3328 | /* |
3329 | * We are going to turn softirqs on, so set the | |
3330 | * usage bit for all held locks, if hardirqs are | |
3331 | * enabled too: | |
3332 | */ | |
3333 | if (curr->hardirqs_enabled) | |
436a49ae | 3334 | mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ); |
dd4e5d3a | 3335 | current->lockdep_recursion = 0; |
8e18257d PZ |
3336 | } |
3337 | ||
3338 | /* | |
3339 | * Softirqs were disabled: | |
3340 | */ | |
3341 | void trace_softirqs_off(unsigned long ip) | |
3342 | { | |
3343 | struct task_struct *curr = current; | |
3344 | ||
dd4e5d3a | 3345 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
3346 | return; |
3347 | ||
0119fee4 PZ |
3348 | /* |
3349 | * We fancy IRQs being disabled here, see softirq.c | |
3350 | */ | |
8e18257d PZ |
3351 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3352 | return; | |
3353 | ||
3354 | if (curr->softirqs_enabled) { | |
3355 | /* | |
3356 | * We have done an ON -> OFF transition: | |
3357 | */ | |
3358 | curr->softirqs_enabled = 0; | |
3359 | curr->softirq_disable_ip = ip; | |
3360 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 3361 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
3362 | /* |
3363 | * Whoops, we wanted softirqs off, so why aren't they? | |
3364 | */ | |
8e18257d PZ |
3365 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
3366 | } else | |
bd6d29c2 | 3367 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
3368 | } |
3369 | ||
3370 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) | |
3371 | { | |
3372 | /* | |
3373 | * If non-trylock use in a hardirq or softirq context, then | |
3374 | * mark the lock as used in these contexts: | |
3375 | */ | |
3376 | if (!hlock->trylock) { | |
3377 | if (hlock->read) { | |
3378 | if (curr->hardirq_context) | |
3379 | if (!mark_lock(curr, hlock, | |
3380 | LOCK_USED_IN_HARDIRQ_READ)) | |
3381 | return 0; | |
3382 | if (curr->softirq_context) | |
3383 | if (!mark_lock(curr, hlock, | |
3384 | LOCK_USED_IN_SOFTIRQ_READ)) | |
3385 | return 0; | |
3386 | } else { | |
3387 | if (curr->hardirq_context) | |
3388 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
3389 | return 0; | |
3390 | if (curr->softirq_context) | |
3391 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
3392 | return 0; | |
3393 | } | |
3394 | } | |
3395 | if (!hlock->hardirqs_off) { | |
3396 | if (hlock->read) { | |
3397 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3398 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
3399 | return 0; |
3400 | if (curr->softirqs_enabled) | |
3401 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3402 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
3403 | return 0; |
3404 | } else { | |
3405 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3406 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
3407 | return 0; |
3408 | if (curr->softirqs_enabled) | |
3409 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3410 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
3411 | return 0; |
3412 | } | |
3413 | } | |
3414 | ||
3415 | return 1; | |
3416 | } | |
3417 | ||
c2469756 BF |
3418 | static inline unsigned int task_irq_context(struct task_struct *task) |
3419 | { | |
3420 | return 2 * !!task->hardirq_context + !!task->softirq_context; | |
3421 | } | |
3422 | ||
8e18257d PZ |
3423 | static int separate_irq_context(struct task_struct *curr, |
3424 | struct held_lock *hlock) | |
3425 | { | |
3426 | unsigned int depth = curr->lockdep_depth; | |
3427 | ||
3428 | /* | |
3429 | * Keep track of points where we cross into an interrupt context: | |
3430 | */ | |
8e18257d PZ |
3431 | if (depth) { |
3432 | struct held_lock *prev_hlock; | |
3433 | ||
3434 | prev_hlock = curr->held_locks + depth-1; | |
3435 | /* | |
3436 | * If we cross into another context, reset the | |
3437 | * hash key (this also prevents the checking and the | |
3438 | * adding of the dependency to 'prev'): | |
3439 | */ | |
3440 | if (prev_hlock->irq_context != hlock->irq_context) | |
3441 | return 1; | |
3442 | } | |
3443 | return 0; | |
fbb9ce95 IM |
3444 | } |
3445 | ||
0119fee4 | 3446 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 3447 | |
8e18257d PZ |
3448 | static inline |
3449 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
3450 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 3451 | { |
0119fee4 | 3452 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
3453 | return 1; |
3454 | } | |
fbb9ce95 | 3455 | |
8e18257d PZ |
3456 | static inline int mark_irqflags(struct task_struct *curr, |
3457 | struct held_lock *hlock) | |
3458 | { | |
3459 | return 1; | |
3460 | } | |
fbb9ce95 | 3461 | |
c2469756 BF |
3462 | static inline unsigned int task_irq_context(struct task_struct *task) |
3463 | { | |
3464 | return 0; | |
3465 | } | |
3466 | ||
8e18257d PZ |
3467 | static inline int separate_irq_context(struct task_struct *curr, |
3468 | struct held_lock *hlock) | |
3469 | { | |
3470 | return 0; | |
fbb9ce95 IM |
3471 | } |
3472 | ||
0119fee4 | 3473 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
3474 | |
3475 | /* | |
8e18257d | 3476 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 3477 | */ |
1d09daa5 | 3478 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 3479 | enum lock_usage_bit new_bit) |
fbb9ce95 | 3480 | { |
8e18257d | 3481 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
3482 | |
3483 | /* | |
8e18257d PZ |
3484 | * If already set then do not dirty the cacheline, |
3485 | * nor do any checks: | |
fbb9ce95 | 3486 | */ |
f82b217e | 3487 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
3488 | return 1; |
3489 | ||
3490 | if (!graph_lock()) | |
3491 | return 0; | |
fbb9ce95 | 3492 | /* |
25985edc | 3493 | * Make sure we didn't race: |
fbb9ce95 | 3494 | */ |
f82b217e | 3495 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
3496 | graph_unlock(); |
3497 | return 1; | |
3498 | } | |
fbb9ce95 | 3499 | |
f82b217e | 3500 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 3501 | |
f82b217e | 3502 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 3503 | return 0; |
fbb9ce95 | 3504 | |
8e18257d | 3505 | switch (new_bit) { |
5346417e PZ |
3506 | #define LOCKDEP_STATE(__STATE) \ |
3507 | case LOCK_USED_IN_##__STATE: \ | |
3508 | case LOCK_USED_IN_##__STATE##_READ: \ | |
3509 | case LOCK_ENABLED_##__STATE: \ | |
3510 | case LOCK_ENABLED_##__STATE##_READ: | |
3511 | #include "lockdep_states.h" | |
3512 | #undef LOCKDEP_STATE | |
8e18257d PZ |
3513 | ret = mark_lock_irq(curr, this, new_bit); |
3514 | if (!ret) | |
3515 | return 0; | |
3516 | break; | |
3517 | case LOCK_USED: | |
bd6d29c2 | 3518 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
3519 | break; |
3520 | default: | |
3521 | if (!debug_locks_off_graph_unlock()) | |
3522 | return 0; | |
3523 | WARN_ON(1); | |
3524 | return 0; | |
3525 | } | |
fbb9ce95 | 3526 | |
8e18257d PZ |
3527 | graph_unlock(); |
3528 | ||
3529 | /* | |
3530 | * We must printk outside of the graph_lock: | |
3531 | */ | |
3532 | if (ret == 2) { | |
3533 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
3534 | print_lock(this); | |
3535 | print_irqtrace_events(curr); | |
3536 | dump_stack(); | |
3537 | } | |
3538 | ||
3539 | return ret; | |
3540 | } | |
fbb9ce95 IM |
3541 | |
3542 | /* | |
3543 | * Initialize a lock instance's lock-class mapping info: | |
3544 | */ | |
d35568bd | 3545 | void lockdep_init_map(struct lockdep_map *lock, const char *name, |
4dfbb9d8 | 3546 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 3547 | { |
d3d03d4f YZ |
3548 | int i; |
3549 | ||
d3d03d4f YZ |
3550 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) |
3551 | lock->class_cache[i] = NULL; | |
62016250 | 3552 | |
c8a25005 PZ |
3553 | #ifdef CONFIG_LOCK_STAT |
3554 | lock->cpu = raw_smp_processor_id(); | |
3555 | #endif | |
3556 | ||
0119fee4 PZ |
3557 | /* |
3558 | * Can't be having no nameless bastards around this place! | |
3559 | */ | |
c8a25005 PZ |
3560 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
3561 | lock->name = "NULL"; | |
fbb9ce95 | 3562 | return; |
c8a25005 PZ |
3563 | } |
3564 | ||
3565 | lock->name = name; | |
fbb9ce95 | 3566 | |
0119fee4 PZ |
3567 | /* |
3568 | * No key, no joy, we need to hash something. | |
3569 | */ | |
fbb9ce95 IM |
3570 | if (DEBUG_LOCKS_WARN_ON(!key)) |
3571 | return; | |
fbb9ce95 | 3572 | /* |
108c1485 BVA |
3573 | * Sanity check, the lock-class key must either have been allocated |
3574 | * statically or must have been registered as a dynamic key. | |
fbb9ce95 | 3575 | */ |
108c1485 BVA |
3576 | if (!static_obj(key) && !is_dynamic_key(key)) { |
3577 | if (debug_locks) | |
3578 | printk(KERN_ERR "BUG: key %px has not been registered!\n", key); | |
fbb9ce95 IM |
3579 | DEBUG_LOCKS_WARN_ON(1); |
3580 | return; | |
3581 | } | |
fbb9ce95 | 3582 | lock->key = key; |
c8a25005 PZ |
3583 | |
3584 | if (unlikely(!debug_locks)) | |
3585 | return; | |
3586 | ||
35a9393c PZ |
3587 | if (subclass) { |
3588 | unsigned long flags; | |
3589 | ||
3590 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3591 | return; | |
3592 | ||
3593 | raw_local_irq_save(flags); | |
3594 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3595 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3596 | current->lockdep_recursion = 0; |
3597 | raw_local_irq_restore(flags); | |
3598 | } | |
fbb9ce95 | 3599 | } |
fbb9ce95 IM |
3600 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3601 | ||
1704f47b | 3602 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3603 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3604 | |
d0945950 ML |
3605 | static int |
3606 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3607 | struct held_lock *hlock, | |
3608 | unsigned long ip) | |
3609 | { | |
3610 | if (!debug_locks_off()) | |
3611 | return 0; | |
3612 | if (debug_locks_silent) | |
3613 | return 0; | |
3614 | ||
681fbec8 | 3615 | pr_warn("\n"); |
a5dd63ef PM |
3616 | pr_warn("==================================\n"); |
3617 | pr_warn("WARNING: Nested lock was not taken\n"); | |
d0945950 | 3618 | print_kernel_ident(); |
a5dd63ef | 3619 | pr_warn("----------------------------------\n"); |
d0945950 | 3620 | |
681fbec8 | 3621 | pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); |
d0945950 ML |
3622 | print_lock(hlock); |
3623 | ||
681fbec8 PM |
3624 | pr_warn("\nbut this task is not holding:\n"); |
3625 | pr_warn("%s\n", hlock->nest_lock->name); | |
d0945950 | 3626 | |
681fbec8 | 3627 | pr_warn("\nstack backtrace:\n"); |
d0945950 ML |
3628 | dump_stack(); |
3629 | ||
681fbec8 | 3630 | pr_warn("\nother info that might help us debug this:\n"); |
d0945950 ML |
3631 | lockdep_print_held_locks(curr); |
3632 | ||
681fbec8 | 3633 | pr_warn("\nstack backtrace:\n"); |
d0945950 ML |
3634 | dump_stack(); |
3635 | ||
3636 | return 0; | |
3637 | } | |
3638 | ||
08f36ff6 | 3639 | static int __lock_is_held(const struct lockdep_map *lock, int read); |
d0945950 | 3640 | |
fbb9ce95 IM |
3641 | /* |
3642 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3643 | * We maintain the dependency maps and validate the locking attempt: | |
8ee10862 WL |
3644 | * |
3645 | * The callers must make sure that IRQs are disabled before calling it, | |
3646 | * otherwise we could get an interrupt which would want to take locks, | |
3647 | * which would end up in lockdep again. | |
fbb9ce95 IM |
3648 | */ |
3649 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3650 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3651 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3652 | int references, int pin_count) |
fbb9ce95 IM |
3653 | { |
3654 | struct task_struct *curr = current; | |
d6d897ce | 3655 | struct lock_class *class = NULL; |
fbb9ce95 | 3656 | struct held_lock *hlock; |
5f18ab5c | 3657 | unsigned int depth; |
fbb9ce95 | 3658 | int chain_head = 0; |
bb97a91e | 3659 | int class_idx; |
fbb9ce95 IM |
3660 | u64 chain_key; |
3661 | ||
3662 | if (unlikely(!debug_locks)) | |
3663 | return 0; | |
3664 | ||
fb9edbe9 ON |
3665 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3666 | check = 0; | |
1704f47b | 3667 | |
62016250 HM |
3668 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3669 | class = lock->class_cache[subclass]; | |
d6d897ce | 3670 | /* |
62016250 | 3671 | * Not cached? |
d6d897ce | 3672 | */ |
fbb9ce95 | 3673 | if (unlikely(!class)) { |
4dfbb9d8 | 3674 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3675 | if (!class) |
3676 | return 0; | |
3677 | } | |
8ca2b56c WL |
3678 | |
3679 | debug_class_ops_inc(class); | |
3680 | ||
fbb9ce95 | 3681 | if (very_verbose(class)) { |
04860d48 | 3682 | printk("\nacquire class [%px] %s", class->key, class->name); |
fbb9ce95 | 3683 | if (class->name_version > 1) |
f943fe0f DV |
3684 | printk(KERN_CONT "#%d", class->name_version); |
3685 | printk(KERN_CONT "\n"); | |
fbb9ce95 IM |
3686 | dump_stack(); |
3687 | } | |
3688 | ||
3689 | /* | |
3690 | * Add the lock to the list of currently held locks. | |
3691 | * (we dont increase the depth just yet, up until the | |
3692 | * dependency checks are done) | |
3693 | */ | |
3694 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3695 | /* |
3696 | * Ran out of static storage for our per-task lock stack again have we? | |
3697 | */ | |
fbb9ce95 IM |
3698 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3699 | return 0; | |
3700 | ||
bb97a91e PZ |
3701 | class_idx = class - lock_classes + 1; |
3702 | ||
e966eaee | 3703 | if (depth) { |
bb97a91e PZ |
3704 | hlock = curr->held_locks + depth - 1; |
3705 | if (hlock->class_idx == class_idx && nest_lock) { | |
7fb4a2ce PZ |
3706 | if (hlock->references) { |
3707 | /* | |
3708 | * Check: unsigned int references:12, overflow. | |
3709 | */ | |
3710 | if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) | |
3711 | return 0; | |
3712 | ||
bb97a91e | 3713 | hlock->references++; |
7fb4a2ce | 3714 | } else { |
bb97a91e | 3715 | hlock->references = 2; |
7fb4a2ce | 3716 | } |
bb97a91e PZ |
3717 | |
3718 | return 1; | |
3719 | } | |
3720 | } | |
3721 | ||
fbb9ce95 | 3722 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3723 | /* |
3724 | * Plain impossible, we just registered it and checked it weren't no | |
3725 | * NULL like.. I bet this mushroom I ate was good! | |
3726 | */ | |
f82b217e DJ |
3727 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3728 | return 0; | |
bb97a91e | 3729 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3730 | hlock->acquire_ip = ip; |
3731 | hlock->instance = lock; | |
7531e2f3 | 3732 | hlock->nest_lock = nest_lock; |
c2469756 | 3733 | hlock->irq_context = task_irq_context(curr); |
fbb9ce95 IM |
3734 | hlock->trylock = trylock; |
3735 | hlock->read = read; | |
3736 | hlock->check = check; | |
6951b12a | 3737 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3738 | hlock->references = references; |
f20786ff PZ |
3739 | #ifdef CONFIG_LOCK_STAT |
3740 | hlock->waittime_stamp = 0; | |
3365e779 | 3741 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3742 | #endif |
21199f27 | 3743 | hlock->pin_count = pin_count; |
fbb9ce95 | 3744 | |
fb9edbe9 | 3745 | if (check && !mark_irqflags(curr, hlock)) |
8e18257d PZ |
3746 | return 0; |
3747 | ||
fbb9ce95 | 3748 | /* mark it as used: */ |
4ff773bb | 3749 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3750 | return 0; |
8e18257d | 3751 | |
fbb9ce95 | 3752 | /* |
17aacfb9 | 3753 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3754 | * lock keys along the dependency chain. We save the hash value |
3755 | * at every step so that we can get the current hash easily | |
3756 | * after unlock. The chain hash is then used to cache dependency | |
3757 | * results. | |
3758 | * | |
3759 | * The 'key ID' is what is the most compact key value to drive | |
3760 | * the hash, not class->key. | |
3761 | */ | |
0119fee4 PZ |
3762 | /* |
3763 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3764 | */ | |
5f18ab5c | 3765 | if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) |
fbb9ce95 IM |
3766 | return 0; |
3767 | ||
3768 | chain_key = curr->curr_chain_key; | |
3769 | if (!depth) { | |
0119fee4 PZ |
3770 | /* |
3771 | * How can we have a chain hash when we ain't got no keys?! | |
3772 | */ | |
fbb9ce95 IM |
3773 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3774 | return 0; | |
3775 | chain_head = 1; | |
3776 | } | |
3777 | ||
3778 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3779 | if (separate_irq_context(curr, hlock)) { |
3780 | chain_key = 0; | |
3781 | chain_head = 1; | |
fbb9ce95 | 3782 | } |
5f18ab5c | 3783 | chain_key = iterate_chain_key(chain_key, class_idx); |
fbb9ce95 | 3784 | |
f8319483 | 3785 | if (nest_lock && !__lock_is_held(nest_lock, -1)) |
d0945950 ML |
3786 | return print_lock_nested_lock_not_held(curr, hlock, ip); |
3787 | ||
a0b0fd53 BVA |
3788 | if (!debug_locks_silent) { |
3789 | WARN_ON_ONCE(depth && !hlock_class(hlock - 1)->key); | |
3790 | WARN_ON_ONCE(!hlock_class(hlock)->key); | |
3791 | } | |
3792 | ||
3aa416b0 | 3793 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3794 | return 0; |
381a2292 | 3795 | |
3aa416b0 | 3796 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3797 | curr->lockdep_depth++; |
3798 | check_chain_key(curr); | |
60e114d1 JP |
3799 | #ifdef CONFIG_DEBUG_LOCKDEP |
3800 | if (unlikely(!debug_locks)) | |
3801 | return 0; | |
3802 | #endif | |
fbb9ce95 IM |
3803 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3804 | debug_locks_off(); | |
2c522836 DJ |
3805 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3806 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3807 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3808 | |
3809 | lockdep_print_held_locks(current); | |
3810 | debug_show_all_locks(); | |
eedeeabd | 3811 | dump_stack(); |
c0540606 | 3812 | |
fbb9ce95 IM |
3813 | return 0; |
3814 | } | |
381a2292 | 3815 | |
fbb9ce95 IM |
3816 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3817 | max_lockdep_depth = curr->lockdep_depth; | |
3818 | ||
3819 | return 1; | |
3820 | } | |
3821 | ||
3822 | static int | |
f86f7554 | 3823 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3824 | unsigned long ip) |
3825 | { | |
3826 | if (!debug_locks_off()) | |
3827 | return 0; | |
3828 | if (debug_locks_silent) | |
3829 | return 0; | |
3830 | ||
681fbec8 | 3831 | pr_warn("\n"); |
a5dd63ef PM |
3832 | pr_warn("=====================================\n"); |
3833 | pr_warn("WARNING: bad unlock balance detected!\n"); | |
fbdc4b9a | 3834 | print_kernel_ident(); |
a5dd63ef | 3835 | pr_warn("-------------------------------------\n"); |
681fbec8 | 3836 | pr_warn("%s/%d is trying to release lock (", |
ba25f9dc | 3837 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 3838 | print_lockdep_cache(lock); |
681fbec8 | 3839 | pr_cont(") at:\n"); |
fbb9ce95 | 3840 | print_ip_sym(ip); |
681fbec8 PM |
3841 | pr_warn("but there are no more locks to release!\n"); |
3842 | pr_warn("\nother info that might help us debug this:\n"); | |
fbb9ce95 IM |
3843 | lockdep_print_held_locks(curr); |
3844 | ||
681fbec8 | 3845 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
3846 | dump_stack(); |
3847 | ||
3848 | return 0; | |
3849 | } | |
3850 | ||
08f36ff6 MW |
3851 | static int match_held_lock(const struct held_lock *hlock, |
3852 | const struct lockdep_map *lock) | |
bb97a91e PZ |
3853 | { |
3854 | if (hlock->instance == lock) | |
3855 | return 1; | |
3856 | ||
3857 | if (hlock->references) { | |
08f36ff6 | 3858 | const struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3859 | |
3860 | if (!class) | |
3861 | class = look_up_lock_class(lock, 0); | |
3862 | ||
80e0401e PZ |
3863 | /* |
3864 | * If look_up_lock_class() failed to find a class, we're trying | |
3865 | * to test if we hold a lock that has never yet been acquired. | |
3866 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3867 | * holding it either, so report failure. | |
3868 | */ | |
64f29d1b | 3869 | if (!class) |
bb97a91e PZ |
3870 | return 0; |
3871 | ||
0119fee4 PZ |
3872 | /* |
3873 | * References, but not a lock we're actually ref-counting? | |
3874 | * State got messed up, follow the sites that change ->references | |
3875 | * and try to make sense of it. | |
3876 | */ | |
bb97a91e PZ |
3877 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3878 | return 0; | |
3879 | ||
3880 | if (hlock->class_idx == class - lock_classes + 1) | |
3881 | return 1; | |
3882 | } | |
3883 | ||
3884 | return 0; | |
3885 | } | |
3886 | ||
41c2c5b8 O |
3887 | /* @depth must not be zero */ |
3888 | static struct held_lock *find_held_lock(struct task_struct *curr, | |
3889 | struct lockdep_map *lock, | |
3890 | unsigned int depth, int *idx) | |
3891 | { | |
3892 | struct held_lock *ret, *hlock, *prev_hlock; | |
3893 | int i; | |
3894 | ||
3895 | i = depth - 1; | |
3896 | hlock = curr->held_locks + i; | |
3897 | ret = hlock; | |
3898 | if (match_held_lock(hlock, lock)) | |
3899 | goto out; | |
3900 | ||
3901 | ret = NULL; | |
3902 | for (i--, prev_hlock = hlock--; | |
3903 | i >= 0; | |
3904 | i--, prev_hlock = hlock--) { | |
3905 | /* | |
3906 | * We must not cross into another context: | |
3907 | */ | |
3908 | if (prev_hlock->irq_context != hlock->irq_context) { | |
3909 | ret = NULL; | |
3910 | break; | |
3911 | } | |
3912 | if (match_held_lock(hlock, lock)) { | |
3913 | ret = hlock; | |
3914 | break; | |
3915 | } | |
3916 | } | |
3917 | ||
3918 | out: | |
3919 | *idx = i; | |
3920 | return ret; | |
3921 | } | |
3922 | ||
e969970b O |
3923 | static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, |
3924 | int idx) | |
3925 | { | |
3926 | struct held_lock *hlock; | |
3927 | ||
8ee10862 WL |
3928 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3929 | return 0; | |
3930 | ||
e969970b O |
3931 | for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) { |
3932 | if (!__lock_acquire(hlock->instance, | |
3933 | hlock_class(hlock)->subclass, | |
3934 | hlock->trylock, | |
3935 | hlock->read, hlock->check, | |
3936 | hlock->hardirqs_off, | |
3937 | hlock->nest_lock, hlock->acquire_ip, | |
3938 | hlock->references, hlock->pin_count)) | |
3939 | return 1; | |
3940 | } | |
3941 | return 0; | |
3942 | } | |
3943 | ||
64aa348e | 3944 | static int |
00ef9f73 PZ |
3945 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3946 | struct lock_class_key *key, unsigned int subclass, | |
3947 | unsigned long ip) | |
64aa348e PZ |
3948 | { |
3949 | struct task_struct *curr = current; | |
41c2c5b8 | 3950 | struct held_lock *hlock; |
64aa348e PZ |
3951 | struct lock_class *class; |
3952 | unsigned int depth; | |
3953 | int i; | |
3954 | ||
513e1073 WL |
3955 | if (unlikely(!debug_locks)) |
3956 | return 0; | |
3957 | ||
64aa348e | 3958 | depth = curr->lockdep_depth; |
0119fee4 PZ |
3959 | /* |
3960 | * This function is about (re)setting the class of a held lock, | |
3961 | * yet we're not actually holding any locks. Naughty user! | |
3962 | */ | |
64aa348e PZ |
3963 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3964 | return 0; | |
3965 | ||
41c2c5b8 O |
3966 | hlock = find_held_lock(curr, lock, depth, &i); |
3967 | if (!hlock) | |
3968 | return print_unlock_imbalance_bug(curr, lock, ip); | |
64aa348e | 3969 | |
00ef9f73 | 3970 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3971 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3972 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3973 | |
3974 | curr->lockdep_depth = i; | |
3975 | curr->curr_chain_key = hlock->prev_chain_key; | |
3976 | ||
e969970b O |
3977 | if (reacquire_held_locks(curr, depth, i)) |
3978 | return 0; | |
64aa348e | 3979 | |
0119fee4 PZ |
3980 | /* |
3981 | * I took it apart and put it back together again, except now I have | |
3982 | * these 'spare' parts.. where shall I put them. | |
3983 | */ | |
64aa348e PZ |
3984 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3985 | return 0; | |
3986 | return 1; | |
3987 | } | |
3988 | ||
6419c4af O |
3989 | static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
3990 | { | |
3991 | struct task_struct *curr = current; | |
3992 | struct held_lock *hlock; | |
3993 | unsigned int depth; | |
3994 | int i; | |
3995 | ||
71492580 WL |
3996 | if (unlikely(!debug_locks)) |
3997 | return 0; | |
3998 | ||
6419c4af O |
3999 | depth = curr->lockdep_depth; |
4000 | /* | |
4001 | * This function is about (re)setting the class of a held lock, | |
4002 | * yet we're not actually holding any locks. Naughty user! | |
4003 | */ | |
4004 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
4005 | return 0; | |
4006 | ||
4007 | hlock = find_held_lock(curr, lock, depth, &i); | |
4008 | if (!hlock) | |
4009 | return print_unlock_imbalance_bug(curr, lock, ip); | |
4010 | ||
4011 | curr->lockdep_depth = i; | |
4012 | curr->curr_chain_key = hlock->prev_chain_key; | |
4013 | ||
4014 | WARN(hlock->read, "downgrading a read lock"); | |
4015 | hlock->read = 1; | |
4016 | hlock->acquire_ip = ip; | |
4017 | ||
4018 | if (reacquire_held_locks(curr, depth, i)) | |
4019 | return 0; | |
4020 | ||
4021 | /* | |
4022 | * I took it apart and put it back together again, except now I have | |
4023 | * these 'spare' parts.. where shall I put them. | |
4024 | */ | |
4025 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
4026 | return 0; | |
4027 | return 1; | |
4028 | } | |
4029 | ||
fbb9ce95 | 4030 | /* |
e0f56fd7 PZ |
4031 | * Remove the lock to the list of currently held locks - this gets |
4032 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
4033 | * mutex_lock_interruptible()). | |
4034 | * | |
4035 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
4036 | */ |
4037 | static int | |
e0f56fd7 | 4038 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
fbb9ce95 | 4039 | { |
e0f56fd7 | 4040 | struct task_struct *curr = current; |
41c2c5b8 | 4041 | struct held_lock *hlock; |
fbb9ce95 | 4042 | unsigned int depth; |
e966eaee | 4043 | int i; |
fbb9ce95 | 4044 | |
e0f56fd7 PZ |
4045 | if (unlikely(!debug_locks)) |
4046 | return 0; | |
4047 | ||
fbb9ce95 | 4048 | depth = curr->lockdep_depth; |
0119fee4 PZ |
4049 | /* |
4050 | * So we're all set to release this lock.. wait what lock? We don't | |
4051 | * own any locks, you've been drinking again? | |
4052 | */ | |
e0f56fd7 PZ |
4053 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
4054 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 4055 | |
e0f56fd7 PZ |
4056 | /* |
4057 | * Check whether the lock exists in the current stack | |
4058 | * of held locks: | |
4059 | */ | |
41c2c5b8 O |
4060 | hlock = find_held_lock(curr, lock, depth, &i); |
4061 | if (!hlock) | |
4062 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 4063 | |
bb97a91e PZ |
4064 | if (hlock->instance == lock) |
4065 | lock_release_holdtime(hlock); | |
4066 | ||
a24fc60d PZ |
4067 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
4068 | ||
bb97a91e PZ |
4069 | if (hlock->references) { |
4070 | hlock->references--; | |
4071 | if (hlock->references) { | |
4072 | /* | |
4073 | * We had, and after removing one, still have | |
4074 | * references, the current lock stack is still | |
4075 | * valid. We're done! | |
4076 | */ | |
4077 | return 1; | |
4078 | } | |
4079 | } | |
f20786ff | 4080 | |
fbb9ce95 IM |
4081 | /* |
4082 | * We have the right lock to unlock, 'hlock' points to it. | |
4083 | * Now we remove it from the stack, and add back the other | |
4084 | * entries (if any), recalculating the hash along the way: | |
4085 | */ | |
bb97a91e | 4086 | |
fbb9ce95 IM |
4087 | curr->lockdep_depth = i; |
4088 | curr->curr_chain_key = hlock->prev_chain_key; | |
4089 | ||
ce52a18d WL |
4090 | /* |
4091 | * The most likely case is when the unlock is on the innermost | |
4092 | * lock. In this case, we are done! | |
4093 | */ | |
4094 | if (i == depth-1) | |
4095 | return 1; | |
4096 | ||
e969970b O |
4097 | if (reacquire_held_locks(curr, depth, i + 1)) |
4098 | return 0; | |
fbb9ce95 | 4099 | |
0119fee4 PZ |
4100 | /* |
4101 | * We had N bottles of beer on the wall, we drank one, but now | |
4102 | * there's not N-1 bottles of beer left on the wall... | |
4103 | */ | |
ce52a18d | 4104 | DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth-1); |
f20786ff | 4105 | |
ce52a18d WL |
4106 | /* |
4107 | * Since reacquire_held_locks() would have called check_chain_key() | |
4108 | * indirectly via __lock_acquire(), we don't need to do it again | |
4109 | * on return. | |
4110 | */ | |
4111 | return 0; | |
fbb9ce95 IM |
4112 | } |
4113 | ||
2f43c602 MH |
4114 | static nokprobe_inline |
4115 | int __lock_is_held(const struct lockdep_map *lock, int read) | |
fbb9ce95 | 4116 | { |
f607c668 PZ |
4117 | struct task_struct *curr = current; |
4118 | int i; | |
fbb9ce95 | 4119 | |
f607c668 | 4120 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 4121 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 4122 | |
f8319483 PZ |
4123 | if (match_held_lock(hlock, lock)) { |
4124 | if (read == -1 || hlock->read == read) | |
4125 | return 1; | |
4126 | ||
4127 | return 0; | |
4128 | } | |
f607c668 | 4129 | } |
f20786ff | 4130 | |
f607c668 | 4131 | return 0; |
fbb9ce95 IM |
4132 | } |
4133 | ||
e7904a28 PZ |
4134 | static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) |
4135 | { | |
4136 | struct pin_cookie cookie = NIL_COOKIE; | |
4137 | struct task_struct *curr = current; | |
4138 | int i; | |
4139 | ||
4140 | if (unlikely(!debug_locks)) | |
4141 | return cookie; | |
4142 | ||
4143 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4144 | struct held_lock *hlock = curr->held_locks + i; | |
4145 | ||
4146 | if (match_held_lock(hlock, lock)) { | |
4147 | /* | |
4148 | * Grab 16bits of randomness; this is sufficient to not | |
4149 | * be guessable and still allows some pin nesting in | |
4150 | * our u32 pin_count. | |
4151 | */ | |
4152 | cookie.val = 1 + (prandom_u32() >> 16); | |
4153 | hlock->pin_count += cookie.val; | |
4154 | return cookie; | |
4155 | } | |
4156 | } | |
4157 | ||
4158 | WARN(1, "pinning an unheld lock\n"); | |
4159 | return cookie; | |
4160 | } | |
4161 | ||
4162 | static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
fbb9ce95 IM |
4163 | { |
4164 | struct task_struct *curr = current; | |
a24fc60d | 4165 | int i; |
fbb9ce95 | 4166 | |
a24fc60d | 4167 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
4168 | return; |
4169 | ||
a24fc60d PZ |
4170 | for (i = 0; i < curr->lockdep_depth; i++) { |
4171 | struct held_lock *hlock = curr->held_locks + i; | |
4172 | ||
4173 | if (match_held_lock(hlock, lock)) { | |
e7904a28 | 4174 | hlock->pin_count += cookie.val; |
fbb9ce95 | 4175 | return; |
a24fc60d | 4176 | } |
fbb9ce95 IM |
4177 | } |
4178 | ||
a24fc60d | 4179 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
4180 | } |
4181 | ||
e7904a28 | 4182 | static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
f607c668 PZ |
4183 | { |
4184 | struct task_struct *curr = current; | |
4185 | int i; | |
4186 | ||
a24fc60d PZ |
4187 | if (unlikely(!debug_locks)) |
4188 | return; | |
4189 | ||
f607c668 | 4190 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
4191 | struct held_lock *hlock = curr->held_locks + i; |
4192 | ||
a24fc60d PZ |
4193 | if (match_held_lock(hlock, lock)) { |
4194 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
4195 | return; | |
4196 | ||
e7904a28 PZ |
4197 | hlock->pin_count -= cookie.val; |
4198 | ||
4199 | if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n")) | |
4200 | hlock->pin_count = 0; | |
4201 | ||
a24fc60d PZ |
4202 | return; |
4203 | } | |
f607c668 PZ |
4204 | } |
4205 | ||
a24fc60d | 4206 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
4207 | } |
4208 | ||
fbb9ce95 IM |
4209 | /* |
4210 | * Check whether we follow the irq-flags state precisely: | |
4211 | */ | |
1d09daa5 | 4212 | static void check_flags(unsigned long flags) |
fbb9ce95 | 4213 | { |
992860e9 IM |
4214 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
4215 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
4216 | if (!debug_locks) |
4217 | return; | |
4218 | ||
5f9fa8a6 IM |
4219 | if (irqs_disabled_flags(flags)) { |
4220 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
4221 | printk("possible reason: unannotated irqs-off.\n"); | |
4222 | } | |
4223 | } else { | |
4224 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
4225 | printk("possible reason: unannotated irqs-on.\n"); | |
4226 | } | |
4227 | } | |
fbb9ce95 IM |
4228 | |
4229 | /* | |
4230 | * We dont accurately track softirq state in e.g. | |
4231 | * hardirq contexts (such as on 4KSTACKS), so only | |
4232 | * check if not in hardirq contexts: | |
4233 | */ | |
4234 | if (!hardirq_count()) { | |
0119fee4 PZ |
4235 | if (softirq_count()) { |
4236 | /* like the above, but with softirqs */ | |
fbb9ce95 | 4237 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
4238 | } else { |
4239 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 4240 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 4241 | } |
fbb9ce95 IM |
4242 | } |
4243 | ||
4244 | if (!debug_locks) | |
4245 | print_irqtrace_events(current); | |
4246 | #endif | |
4247 | } | |
4248 | ||
00ef9f73 PZ |
4249 | void lock_set_class(struct lockdep_map *lock, const char *name, |
4250 | struct lock_class_key *key, unsigned int subclass, | |
4251 | unsigned long ip) | |
64aa348e PZ |
4252 | { |
4253 | unsigned long flags; | |
4254 | ||
4255 | if (unlikely(current->lockdep_recursion)) | |
4256 | return; | |
4257 | ||
4258 | raw_local_irq_save(flags); | |
4259 | current->lockdep_recursion = 1; | |
4260 | check_flags(flags); | |
00ef9f73 | 4261 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
4262 | check_chain_key(current); |
4263 | current->lockdep_recursion = 0; | |
4264 | raw_local_irq_restore(flags); | |
4265 | } | |
00ef9f73 | 4266 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 4267 | |
6419c4af O |
4268 | void lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
4269 | { | |
4270 | unsigned long flags; | |
4271 | ||
4272 | if (unlikely(current->lockdep_recursion)) | |
4273 | return; | |
4274 | ||
4275 | raw_local_irq_save(flags); | |
4276 | current->lockdep_recursion = 1; | |
4277 | check_flags(flags); | |
4278 | if (__lock_downgrade(lock, ip)) | |
4279 | check_chain_key(current); | |
4280 | current->lockdep_recursion = 0; | |
4281 | raw_local_irq_restore(flags); | |
4282 | } | |
4283 | EXPORT_SYMBOL_GPL(lock_downgrade); | |
4284 | ||
fbb9ce95 IM |
4285 | /* |
4286 | * We are not always called with irqs disabled - do that here, | |
4287 | * and also avoid lockdep recursion: | |
4288 | */ | |
1d09daa5 | 4289 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
4290 | int trylock, int read, int check, |
4291 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
4292 | { |
4293 | unsigned long flags; | |
4294 | ||
4295 | if (unlikely(current->lockdep_recursion)) | |
4296 | return; | |
4297 | ||
4298 | raw_local_irq_save(flags); | |
4299 | check_flags(flags); | |
4300 | ||
4301 | current->lockdep_recursion = 1; | |
db2c4c77 | 4302 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 4303 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 4304 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
4305 | current->lockdep_recursion = 0; |
4306 | raw_local_irq_restore(flags); | |
4307 | } | |
fbb9ce95 IM |
4308 | EXPORT_SYMBOL_GPL(lock_acquire); |
4309 | ||
1d09daa5 | 4310 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 4311 | unsigned long ip) |
fbb9ce95 IM |
4312 | { |
4313 | unsigned long flags; | |
4314 | ||
4315 | if (unlikely(current->lockdep_recursion)) | |
4316 | return; | |
4317 | ||
4318 | raw_local_irq_save(flags); | |
4319 | check_flags(flags); | |
4320 | current->lockdep_recursion = 1; | |
93135439 | 4321 | trace_lock_release(lock, ip); |
e0f56fd7 PZ |
4322 | if (__lock_release(lock, nested, ip)) |
4323 | check_chain_key(current); | |
fbb9ce95 IM |
4324 | current->lockdep_recursion = 0; |
4325 | raw_local_irq_restore(flags); | |
4326 | } | |
fbb9ce95 IM |
4327 | EXPORT_SYMBOL_GPL(lock_release); |
4328 | ||
08f36ff6 | 4329 | int lock_is_held_type(const struct lockdep_map *lock, int read) |
f607c668 PZ |
4330 | { |
4331 | unsigned long flags; | |
4332 | int ret = 0; | |
4333 | ||
4334 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 4335 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
4336 | |
4337 | raw_local_irq_save(flags); | |
4338 | check_flags(flags); | |
4339 | ||
4340 | current->lockdep_recursion = 1; | |
f8319483 | 4341 | ret = __lock_is_held(lock, read); |
f607c668 PZ |
4342 | current->lockdep_recursion = 0; |
4343 | raw_local_irq_restore(flags); | |
4344 | ||
4345 | return ret; | |
4346 | } | |
f8319483 | 4347 | EXPORT_SYMBOL_GPL(lock_is_held_type); |
2f43c602 | 4348 | NOKPROBE_SYMBOL(lock_is_held_type); |
f607c668 | 4349 | |
e7904a28 | 4350 | struct pin_cookie lock_pin_lock(struct lockdep_map *lock) |
a24fc60d | 4351 | { |
e7904a28 | 4352 | struct pin_cookie cookie = NIL_COOKIE; |
a24fc60d PZ |
4353 | unsigned long flags; |
4354 | ||
4355 | if (unlikely(current->lockdep_recursion)) | |
e7904a28 | 4356 | return cookie; |
a24fc60d PZ |
4357 | |
4358 | raw_local_irq_save(flags); | |
4359 | check_flags(flags); | |
4360 | ||
4361 | current->lockdep_recursion = 1; | |
e7904a28 | 4362 | cookie = __lock_pin_lock(lock); |
a24fc60d PZ |
4363 | current->lockdep_recursion = 0; |
4364 | raw_local_irq_restore(flags); | |
e7904a28 PZ |
4365 | |
4366 | return cookie; | |
a24fc60d PZ |
4367 | } |
4368 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
4369 | ||
e7904a28 PZ |
4370 | void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
4371 | { | |
4372 | unsigned long flags; | |
4373 | ||
4374 | if (unlikely(current->lockdep_recursion)) | |
4375 | return; | |
4376 | ||
4377 | raw_local_irq_save(flags); | |
4378 | check_flags(flags); | |
4379 | ||
4380 | current->lockdep_recursion = 1; | |
4381 | __lock_repin_lock(lock, cookie); | |
4382 | current->lockdep_recursion = 0; | |
4383 | raw_local_irq_restore(flags); | |
4384 | } | |
4385 | EXPORT_SYMBOL_GPL(lock_repin_lock); | |
4386 | ||
4387 | void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
a24fc60d PZ |
4388 | { |
4389 | unsigned long flags; | |
4390 | ||
4391 | if (unlikely(current->lockdep_recursion)) | |
4392 | return; | |
4393 | ||
4394 | raw_local_irq_save(flags); | |
4395 | check_flags(flags); | |
4396 | ||
4397 | current->lockdep_recursion = 1; | |
e7904a28 | 4398 | __lock_unpin_lock(lock, cookie); |
a24fc60d PZ |
4399 | current->lockdep_recursion = 0; |
4400 | raw_local_irq_restore(flags); | |
4401 | } | |
4402 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
4403 | ||
f20786ff PZ |
4404 | #ifdef CONFIG_LOCK_STAT |
4405 | static int | |
4406 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
4407 | unsigned long ip) | |
4408 | { | |
4409 | if (!debug_locks_off()) | |
4410 | return 0; | |
4411 | if (debug_locks_silent) | |
4412 | return 0; | |
4413 | ||
681fbec8 | 4414 | pr_warn("\n"); |
a5dd63ef PM |
4415 | pr_warn("=================================\n"); |
4416 | pr_warn("WARNING: bad contention detected!\n"); | |
fbdc4b9a | 4417 | print_kernel_ident(); |
a5dd63ef | 4418 | pr_warn("---------------------------------\n"); |
681fbec8 | 4419 | pr_warn("%s/%d is trying to contend lock (", |
ba25f9dc | 4420 | curr->comm, task_pid_nr(curr)); |
f20786ff | 4421 | print_lockdep_cache(lock); |
681fbec8 | 4422 | pr_cont(") at:\n"); |
f20786ff | 4423 | print_ip_sym(ip); |
681fbec8 PM |
4424 | pr_warn("but there are no locks held!\n"); |
4425 | pr_warn("\nother info that might help us debug this:\n"); | |
f20786ff PZ |
4426 | lockdep_print_held_locks(curr); |
4427 | ||
681fbec8 | 4428 | pr_warn("\nstack backtrace:\n"); |
f20786ff PZ |
4429 | dump_stack(); |
4430 | ||
4431 | return 0; | |
4432 | } | |
4433 | ||
4434 | static void | |
4435 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4436 | { | |
4437 | struct task_struct *curr = current; | |
41c2c5b8 | 4438 | struct held_lock *hlock; |
f20786ff PZ |
4439 | struct lock_class_stats *stats; |
4440 | unsigned int depth; | |
c7e78cff | 4441 | int i, contention_point, contending_point; |
f20786ff PZ |
4442 | |
4443 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4444 | /* |
4445 | * Whee, we contended on this lock, except it seems we're not | |
4446 | * actually trying to acquire anything much at all.. | |
4447 | */ | |
f20786ff PZ |
4448 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4449 | return; | |
4450 | ||
41c2c5b8 O |
4451 | hlock = find_held_lock(curr, lock, depth, &i); |
4452 | if (!hlock) { | |
4453 | print_lock_contention_bug(curr, lock, ip); | |
4454 | return; | |
f20786ff | 4455 | } |
f20786ff | 4456 | |
bb97a91e PZ |
4457 | if (hlock->instance != lock) |
4458 | return; | |
4459 | ||
3365e779 | 4460 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 4461 | |
c7e78cff PZ |
4462 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
4463 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
4464 | lock->ip); | |
f20786ff | 4465 | |
f82b217e | 4466 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
4467 | if (contention_point < LOCKSTAT_POINTS) |
4468 | stats->contention_point[contention_point]++; | |
4469 | if (contending_point < LOCKSTAT_POINTS) | |
4470 | stats->contending_point[contending_point]++; | |
96645678 PZ |
4471 | if (lock->cpu != smp_processor_id()) |
4472 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
4473 | } |
4474 | ||
4475 | static void | |
c7e78cff | 4476 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4477 | { |
4478 | struct task_struct *curr = current; | |
41c2c5b8 | 4479 | struct held_lock *hlock; |
f20786ff PZ |
4480 | struct lock_class_stats *stats; |
4481 | unsigned int depth; | |
3365e779 | 4482 | u64 now, waittime = 0; |
96645678 | 4483 | int i, cpu; |
f20786ff PZ |
4484 | |
4485 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4486 | /* |
4487 | * Yay, we acquired ownership of this lock we didn't try to | |
4488 | * acquire, how the heck did that happen? | |
4489 | */ | |
f20786ff PZ |
4490 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4491 | return; | |
4492 | ||
41c2c5b8 O |
4493 | hlock = find_held_lock(curr, lock, depth, &i); |
4494 | if (!hlock) { | |
4495 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
4496 | return; | |
f20786ff | 4497 | } |
f20786ff | 4498 | |
bb97a91e PZ |
4499 | if (hlock->instance != lock) |
4500 | return; | |
4501 | ||
96645678 PZ |
4502 | cpu = smp_processor_id(); |
4503 | if (hlock->waittime_stamp) { | |
3365e779 | 4504 | now = lockstat_clock(); |
96645678 PZ |
4505 | waittime = now - hlock->waittime_stamp; |
4506 | hlock->holdtime_stamp = now; | |
4507 | } | |
f20786ff | 4508 | |
883a2a31 | 4509 | trace_lock_acquired(lock, ip); |
2062501a | 4510 | |
f82b217e | 4511 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
4512 | if (waittime) { |
4513 | if (hlock->read) | |
4514 | lock_time_inc(&stats->read_waittime, waittime); | |
4515 | else | |
4516 | lock_time_inc(&stats->write_waittime, waittime); | |
4517 | } | |
4518 | if (lock->cpu != cpu) | |
4519 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
96645678 PZ |
4520 | |
4521 | lock->cpu = cpu; | |
c7e78cff | 4522 | lock->ip = ip; |
f20786ff PZ |
4523 | } |
4524 | ||
4525 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4526 | { | |
4527 | unsigned long flags; | |
4528 | ||
9506a742 | 4529 | if (unlikely(!lock_stat || !debug_locks)) |
f20786ff PZ |
4530 | return; |
4531 | ||
4532 | if (unlikely(current->lockdep_recursion)) | |
4533 | return; | |
4534 | ||
4535 | raw_local_irq_save(flags); | |
4536 | check_flags(flags); | |
4537 | current->lockdep_recursion = 1; | |
db2c4c77 | 4538 | trace_lock_contended(lock, ip); |
f20786ff PZ |
4539 | __lock_contended(lock, ip); |
4540 | current->lockdep_recursion = 0; | |
4541 | raw_local_irq_restore(flags); | |
4542 | } | |
4543 | EXPORT_SYMBOL_GPL(lock_contended); | |
4544 | ||
c7e78cff | 4545 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4546 | { |
4547 | unsigned long flags; | |
4548 | ||
9506a742 | 4549 | if (unlikely(!lock_stat || !debug_locks)) |
f20786ff PZ |
4550 | return; |
4551 | ||
4552 | if (unlikely(current->lockdep_recursion)) | |
4553 | return; | |
4554 | ||
4555 | raw_local_irq_save(flags); | |
4556 | check_flags(flags); | |
4557 | current->lockdep_recursion = 1; | |
c7e78cff | 4558 | __lock_acquired(lock, ip); |
f20786ff PZ |
4559 | current->lockdep_recursion = 0; |
4560 | raw_local_irq_restore(flags); | |
4561 | } | |
4562 | EXPORT_SYMBOL_GPL(lock_acquired); | |
4563 | #endif | |
4564 | ||
fbb9ce95 IM |
4565 | /* |
4566 | * Used by the testsuite, sanitize the validator state | |
4567 | * after a simulated failure: | |
4568 | */ | |
4569 | ||
4570 | void lockdep_reset(void) | |
4571 | { | |
4572 | unsigned long flags; | |
23d95a03 | 4573 | int i; |
fbb9ce95 IM |
4574 | |
4575 | raw_local_irq_save(flags); | |
4576 | current->curr_chain_key = 0; | |
4577 | current->lockdep_depth = 0; | |
4578 | current->lockdep_recursion = 0; | |
4579 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
4580 | nr_hardirq_chains = 0; | |
4581 | nr_softirq_chains = 0; | |
4582 | nr_process_chains = 0; | |
4583 | debug_locks = 1; | |
23d95a03 | 4584 | for (i = 0; i < CHAINHASH_SIZE; i++) |
a63f38cc | 4585 | INIT_HLIST_HEAD(chainhash_table + i); |
fbb9ce95 IM |
4586 | raw_local_irq_restore(flags); |
4587 | } | |
4588 | ||
a0b0fd53 | 4589 | /* Remove a class from a lock chain. Must be called with the graph lock held. */ |
de4643a7 BVA |
4590 | static void remove_class_from_lock_chain(struct pending_free *pf, |
4591 | struct lock_chain *chain, | |
a0b0fd53 BVA |
4592 | struct lock_class *class) |
4593 | { | |
4594 | #ifdef CONFIG_PROVE_LOCKING | |
4595 | struct lock_chain *new_chain; | |
4596 | u64 chain_key; | |
4597 | int i; | |
4598 | ||
4599 | for (i = chain->base; i < chain->base + chain->depth; i++) { | |
4600 | if (chain_hlocks[i] != class - lock_classes) | |
4601 | continue; | |
4602 | /* The code below leaks one chain_hlock[] entry. */ | |
72dcd505 | 4603 | if (--chain->depth > 0) { |
a0b0fd53 BVA |
4604 | memmove(&chain_hlocks[i], &chain_hlocks[i + 1], |
4605 | (chain->base + chain->depth - i) * | |
4606 | sizeof(chain_hlocks[0])); | |
72dcd505 | 4607 | } |
a0b0fd53 BVA |
4608 | /* |
4609 | * Each lock class occurs at most once in a lock chain so once | |
4610 | * we found a match we can break out of this loop. | |
4611 | */ | |
4612 | goto recalc; | |
4613 | } | |
4614 | /* Since the chain has not been modified, return. */ | |
4615 | return; | |
4616 | ||
4617 | recalc: | |
4618 | chain_key = 0; | |
4619 | for (i = chain->base; i < chain->base + chain->depth; i++) | |
4620 | chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1); | |
4621 | if (chain->depth && chain->chain_key == chain_key) | |
4622 | return; | |
4623 | /* Overwrite the chain key for concurrent RCU readers. */ | |
4624 | WRITE_ONCE(chain->chain_key, chain_key); | |
4625 | /* | |
4626 | * Note: calling hlist_del_rcu() from inside a | |
4627 | * hlist_for_each_entry_rcu() loop is safe. | |
4628 | */ | |
4629 | hlist_del_rcu(&chain->entry); | |
de4643a7 | 4630 | __set_bit(chain - lock_chains, pf->lock_chains_being_freed); |
a0b0fd53 BVA |
4631 | if (chain->depth == 0) |
4632 | return; | |
4633 | /* | |
4634 | * If the modified lock chain matches an existing lock chain, drop | |
4635 | * the modified lock chain. | |
4636 | */ | |
4637 | if (lookup_chain_cache(chain_key)) | |
4638 | return; | |
de4643a7 BVA |
4639 | new_chain = alloc_lock_chain(); |
4640 | if (WARN_ON_ONCE(!new_chain)) { | |
a0b0fd53 BVA |
4641 | debug_locks_off(); |
4642 | return; | |
4643 | } | |
a0b0fd53 BVA |
4644 | *new_chain = *chain; |
4645 | hlist_add_head_rcu(&new_chain->entry, chainhashentry(chain_key)); | |
4646 | #endif | |
4647 | } | |
4648 | ||
4649 | /* Must be called with the graph lock held. */ | |
de4643a7 BVA |
4650 | static void remove_class_from_lock_chains(struct pending_free *pf, |
4651 | struct lock_class *class) | |
a0b0fd53 BVA |
4652 | { |
4653 | struct lock_chain *chain; | |
4654 | struct hlist_head *head; | |
4655 | int i; | |
4656 | ||
4657 | for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) { | |
4658 | head = chainhash_table + i; | |
4659 | hlist_for_each_entry_rcu(chain, head, entry) { | |
de4643a7 | 4660 | remove_class_from_lock_chain(pf, chain, class); |
a0b0fd53 BVA |
4661 | } |
4662 | } | |
4663 | } | |
4664 | ||
786fa29e BVA |
4665 | /* |
4666 | * Remove all references to a lock class. The caller must hold the graph lock. | |
4667 | */ | |
a0b0fd53 | 4668 | static void zap_class(struct pending_free *pf, struct lock_class *class) |
fbb9ce95 | 4669 | { |
86cffb80 | 4670 | struct lock_list *entry; |
fbb9ce95 IM |
4671 | int i; |
4672 | ||
a0b0fd53 BVA |
4673 | WARN_ON_ONCE(!class->key); |
4674 | ||
fbb9ce95 IM |
4675 | /* |
4676 | * Remove all dependencies this lock is | |
4677 | * involved in: | |
4678 | */ | |
ace35a7a BVA |
4679 | for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) { |
4680 | entry = list_entries + i; | |
86cffb80 BVA |
4681 | if (entry->class != class && entry->links_to != class) |
4682 | continue; | |
ace35a7a BVA |
4683 | __clear_bit(i, list_entries_in_use); |
4684 | nr_list_entries--; | |
86cffb80 | 4685 | list_del_rcu(&entry->entry); |
fbb9ce95 | 4686 | } |
a0b0fd53 BVA |
4687 | if (list_empty(&class->locks_after) && |
4688 | list_empty(&class->locks_before)) { | |
4689 | list_move_tail(&class->lock_entry, &pf->zapped); | |
4690 | hlist_del_rcu(&class->hash_entry); | |
4691 | WRITE_ONCE(class->key, NULL); | |
4692 | WRITE_ONCE(class->name, NULL); | |
4693 | nr_lock_classes--; | |
4694 | } else { | |
4695 | WARN_ONCE(true, "%s() failed for class %s\n", __func__, | |
4696 | class->name); | |
4697 | } | |
fbb9ce95 | 4698 | |
de4643a7 | 4699 | remove_class_from_lock_chains(pf, class); |
a0b0fd53 BVA |
4700 | } |
4701 | ||
4702 | static void reinit_class(struct lock_class *class) | |
4703 | { | |
4704 | void *const p = class; | |
4705 | const unsigned int offset = offsetof(struct lock_class, key); | |
4706 | ||
4707 | WARN_ON_ONCE(!class->lock_entry.next); | |
4708 | WARN_ON_ONCE(!list_empty(&class->locks_after)); | |
4709 | WARN_ON_ONCE(!list_empty(&class->locks_before)); | |
4710 | memset(p + offset, 0, sizeof(*class) - offset); | |
4711 | WARN_ON_ONCE(!class->lock_entry.next); | |
4712 | WARN_ON_ONCE(!list_empty(&class->locks_after)); | |
4713 | WARN_ON_ONCE(!list_empty(&class->locks_before)); | |
fbb9ce95 IM |
4714 | } |
4715 | ||
fabe874a | 4716 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
4717 | { |
4718 | return addr >= start && addr < start + size; | |
4719 | } | |
4720 | ||
a0b0fd53 BVA |
4721 | static bool inside_selftest(void) |
4722 | { | |
4723 | return current == lockdep_selftest_task_struct; | |
4724 | } | |
4725 | ||
4726 | /* The caller must hold the graph lock. */ | |
4727 | static struct pending_free *get_pending_free(void) | |
4728 | { | |
4729 | return delayed_free.pf + delayed_free.index; | |
4730 | } | |
4731 | ||
4732 | static void free_zapped_rcu(struct rcu_head *cb); | |
4733 | ||
4734 | /* | |
4735 | * Schedule an RCU callback if no RCU callback is pending. Must be called with | |
4736 | * the graph lock held. | |
4737 | */ | |
4738 | static void call_rcu_zapped(struct pending_free *pf) | |
4739 | { | |
4740 | WARN_ON_ONCE(inside_selftest()); | |
4741 | ||
4742 | if (list_empty(&pf->zapped)) | |
4743 | return; | |
4744 | ||
4745 | if (delayed_free.scheduled) | |
4746 | return; | |
4747 | ||
4748 | delayed_free.scheduled = true; | |
4749 | ||
4750 | WARN_ON_ONCE(delayed_free.pf + delayed_free.index != pf); | |
4751 | delayed_free.index ^= 1; | |
4752 | ||
4753 | call_rcu(&delayed_free.rcu_head, free_zapped_rcu); | |
4754 | } | |
4755 | ||
4756 | /* The caller must hold the graph lock. May be called from RCU context. */ | |
4757 | static void __free_zapped_classes(struct pending_free *pf) | |
4758 | { | |
4759 | struct lock_class *class; | |
4760 | ||
72dcd505 | 4761 | check_data_structures(); |
b526b2e3 | 4762 | |
a0b0fd53 BVA |
4763 | list_for_each_entry(class, &pf->zapped, lock_entry) |
4764 | reinit_class(class); | |
4765 | ||
4766 | list_splice_init(&pf->zapped, &free_lock_classes); | |
de4643a7 BVA |
4767 | |
4768 | #ifdef CONFIG_PROVE_LOCKING | |
4769 | bitmap_andnot(lock_chains_in_use, lock_chains_in_use, | |
4770 | pf->lock_chains_being_freed, ARRAY_SIZE(lock_chains)); | |
4771 | bitmap_clear(pf->lock_chains_being_freed, 0, ARRAY_SIZE(lock_chains)); | |
4772 | #endif | |
a0b0fd53 BVA |
4773 | } |
4774 | ||
4775 | static void free_zapped_rcu(struct rcu_head *ch) | |
4776 | { | |
4777 | struct pending_free *pf; | |
4778 | unsigned long flags; | |
4779 | ||
4780 | if (WARN_ON_ONCE(ch != &delayed_free.rcu_head)) | |
4781 | return; | |
4782 | ||
4783 | raw_local_irq_save(flags); | |
90c1cba2 BVA |
4784 | arch_spin_lock(&lockdep_lock); |
4785 | current->lockdep_recursion = 1; | |
a0b0fd53 BVA |
4786 | |
4787 | /* closed head */ | |
4788 | pf = delayed_free.pf + (delayed_free.index ^ 1); | |
4789 | __free_zapped_classes(pf); | |
4790 | delayed_free.scheduled = false; | |
4791 | ||
4792 | /* | |
4793 | * If there's anything on the open list, close and start a new callback. | |
4794 | */ | |
4795 | call_rcu_zapped(delayed_free.pf + delayed_free.index); | |
4796 | ||
90c1cba2 BVA |
4797 | current->lockdep_recursion = 0; |
4798 | arch_spin_unlock(&lockdep_lock); | |
a0b0fd53 BVA |
4799 | raw_local_irq_restore(flags); |
4800 | } | |
4801 | ||
4802 | /* | |
4803 | * Remove all lock classes from the class hash table and from the | |
4804 | * all_lock_classes list whose key or name is in the address range [start, | |
4805 | * start + size). Move these lock classes to the zapped_classes list. Must | |
4806 | * be called with the graph lock held. | |
4807 | */ | |
4808 | static void __lockdep_free_key_range(struct pending_free *pf, void *start, | |
4809 | unsigned long size) | |
956f3563 BVA |
4810 | { |
4811 | struct lock_class *class; | |
4812 | struct hlist_head *head; | |
4813 | int i; | |
4814 | ||
4815 | /* Unhash all classes that were created by a module. */ | |
4816 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
4817 | head = classhash_table + i; | |
4818 | hlist_for_each_entry_rcu(class, head, hash_entry) { | |
4819 | if (!within(class->key, start, size) && | |
4820 | !within(class->name, start, size)) | |
4821 | continue; | |
a0b0fd53 | 4822 | zap_class(pf, class); |
956f3563 BVA |
4823 | } |
4824 | } | |
4825 | } | |
4826 | ||
35a9393c PZ |
4827 | /* |
4828 | * Used in module.c to remove lock classes from memory that is going to be | |
4829 | * freed; and possibly re-used by other modules. | |
4830 | * | |
29fc33fb BVA |
4831 | * We will have had one synchronize_rcu() before getting here, so we're |
4832 | * guaranteed nobody will look up these exact classes -- they're properly dead | |
4833 | * but still allocated. | |
35a9393c | 4834 | */ |
a0b0fd53 | 4835 | static void lockdep_free_key_range_reg(void *start, unsigned long size) |
fbb9ce95 | 4836 | { |
a0b0fd53 | 4837 | struct pending_free *pf; |
fbb9ce95 | 4838 | unsigned long flags; |
fbb9ce95 | 4839 | |
feb0a386 BVA |
4840 | init_data_structures_once(); |
4841 | ||
fbb9ce95 | 4842 | raw_local_irq_save(flags); |
90c1cba2 BVA |
4843 | arch_spin_lock(&lockdep_lock); |
4844 | current->lockdep_recursion = 1; | |
a0b0fd53 BVA |
4845 | pf = get_pending_free(); |
4846 | __lockdep_free_key_range(pf, start, size); | |
4847 | call_rcu_zapped(pf); | |
90c1cba2 BVA |
4848 | current->lockdep_recursion = 0; |
4849 | arch_spin_unlock(&lockdep_lock); | |
fbb9ce95 | 4850 | raw_local_irq_restore(flags); |
35a9393c PZ |
4851 | |
4852 | /* | |
4853 | * Wait for any possible iterators from look_up_lock_class() to pass | |
4854 | * before continuing to free the memory they refer to. | |
35a9393c | 4855 | */ |
51959d85 | 4856 | synchronize_rcu(); |
a0b0fd53 | 4857 | } |
35a9393c | 4858 | |
a0b0fd53 BVA |
4859 | /* |
4860 | * Free all lockdep keys in the range [start, start+size). Does not sleep. | |
4861 | * Ignores debug_locks. Must only be used by the lockdep selftests. | |
4862 | */ | |
4863 | static void lockdep_free_key_range_imm(void *start, unsigned long size) | |
4864 | { | |
4865 | struct pending_free *pf = delayed_free.pf; | |
4866 | unsigned long flags; | |
4867 | ||
4868 | init_data_structures_once(); | |
4869 | ||
4870 | raw_local_irq_save(flags); | |
4871 | arch_spin_lock(&lockdep_lock); | |
4872 | __lockdep_free_key_range(pf, start, size); | |
4873 | __free_zapped_classes(pf); | |
4874 | arch_spin_unlock(&lockdep_lock); | |
4875 | raw_local_irq_restore(flags); | |
4876 | } | |
4877 | ||
4878 | void lockdep_free_key_range(void *start, unsigned long size) | |
4879 | { | |
4880 | init_data_structures_once(); | |
4881 | ||
4882 | if (inside_selftest()) | |
4883 | lockdep_free_key_range_imm(start, size); | |
4884 | else | |
4885 | lockdep_free_key_range_reg(start, size); | |
fbb9ce95 IM |
4886 | } |
4887 | ||
2904d9fa BVA |
4888 | /* |
4889 | * Check whether any element of the @lock->class_cache[] array refers to a | |
4890 | * registered lock class. The caller must hold either the graph lock or the | |
4891 | * RCU read lock. | |
4892 | */ | |
4893 | static bool lock_class_cache_is_registered(struct lockdep_map *lock) | |
fbb9ce95 | 4894 | { |
35a9393c | 4895 | struct lock_class *class; |
a63f38cc | 4896 | struct hlist_head *head; |
fbb9ce95 | 4897 | int i, j; |
2904d9fa BVA |
4898 | |
4899 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
4900 | head = classhash_table + i; | |
4901 | hlist_for_each_entry_rcu(class, head, hash_entry) { | |
4902 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
4903 | if (lock->class_cache[j] == class) | |
4904 | return true; | |
4905 | } | |
4906 | } | |
4907 | return false; | |
4908 | } | |
4909 | ||
956f3563 | 4910 | /* The caller must hold the graph lock. Does not sleep. */ |
a0b0fd53 BVA |
4911 | static void __lockdep_reset_lock(struct pending_free *pf, |
4912 | struct lockdep_map *lock) | |
2904d9fa BVA |
4913 | { |
4914 | struct lock_class *class; | |
956f3563 | 4915 | int j; |
fbb9ce95 IM |
4916 | |
4917 | /* | |
d6d897ce IM |
4918 | * Remove all classes this lock might have: |
4919 | */ | |
4920 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
4921 | /* | |
4922 | * If the class exists we look it up and zap it: | |
4923 | */ | |
4924 | class = look_up_lock_class(lock, j); | |
64f29d1b | 4925 | if (class) |
a0b0fd53 | 4926 | zap_class(pf, class); |
d6d897ce IM |
4927 | } |
4928 | /* | |
4929 | * Debug check: in the end all mapped classes should | |
4930 | * be gone. | |
fbb9ce95 | 4931 | */ |
956f3563 BVA |
4932 | if (WARN_ON_ONCE(lock_class_cache_is_registered(lock))) |
4933 | debug_locks_off(); | |
4934 | } | |
4935 | ||
a0b0fd53 BVA |
4936 | /* |
4937 | * Remove all information lockdep has about a lock if debug_locks == 1. Free | |
4938 | * released data structures from RCU context. | |
4939 | */ | |
4940 | static void lockdep_reset_lock_reg(struct lockdep_map *lock) | |
956f3563 | 4941 | { |
a0b0fd53 | 4942 | struct pending_free *pf; |
956f3563 BVA |
4943 | unsigned long flags; |
4944 | int locked; | |
4945 | ||
956f3563 BVA |
4946 | raw_local_irq_save(flags); |
4947 | locked = graph_lock(); | |
a0b0fd53 BVA |
4948 | if (!locked) |
4949 | goto out_irq; | |
4950 | ||
4951 | pf = get_pending_free(); | |
4952 | __lockdep_reset_lock(pf, lock); | |
4953 | call_rcu_zapped(pf); | |
4954 | ||
4955 | graph_unlock(); | |
4956 | out_irq: | |
4957 | raw_local_irq_restore(flags); | |
4958 | } | |
4959 | ||
4960 | /* | |
4961 | * Reset a lock. Does not sleep. Ignores debug_locks. Must only be used by the | |
4962 | * lockdep selftests. | |
4963 | */ | |
4964 | static void lockdep_reset_lock_imm(struct lockdep_map *lock) | |
4965 | { | |
4966 | struct pending_free *pf = delayed_free.pf; | |
4967 | unsigned long flags; | |
4968 | ||
4969 | raw_local_irq_save(flags); | |
4970 | arch_spin_lock(&lockdep_lock); | |
4971 | __lockdep_reset_lock(pf, lock); | |
4972 | __free_zapped_classes(pf); | |
4973 | arch_spin_unlock(&lockdep_lock); | |
fbb9ce95 IM |
4974 | raw_local_irq_restore(flags); |
4975 | } | |
4976 | ||
a0b0fd53 BVA |
4977 | void lockdep_reset_lock(struct lockdep_map *lock) |
4978 | { | |
4979 | init_data_structures_once(); | |
4980 | ||
4981 | if (inside_selftest()) | |
4982 | lockdep_reset_lock_imm(lock); | |
4983 | else | |
4984 | lockdep_reset_lock_reg(lock); | |
4985 | } | |
4986 | ||
108c1485 BVA |
4987 | /* Unregister a dynamically allocated key. */ |
4988 | void lockdep_unregister_key(struct lock_class_key *key) | |
4989 | { | |
4990 | struct hlist_head *hash_head = keyhashentry(key); | |
4991 | struct lock_class_key *k; | |
4992 | struct pending_free *pf; | |
4993 | unsigned long flags; | |
4994 | bool found = false; | |
4995 | ||
4996 | might_sleep(); | |
4997 | ||
4998 | if (WARN_ON_ONCE(static_obj(key))) | |
4999 | return; | |
5000 | ||
5001 | raw_local_irq_save(flags); | |
8b39adbe BVA |
5002 | if (!graph_lock()) |
5003 | goto out_irq; | |
5004 | ||
108c1485 BVA |
5005 | pf = get_pending_free(); |
5006 | hlist_for_each_entry_rcu(k, hash_head, hash_entry) { | |
5007 | if (k == key) { | |
5008 | hlist_del_rcu(&k->hash_entry); | |
5009 | found = true; | |
5010 | break; | |
5011 | } | |
5012 | } | |
5013 | WARN_ON_ONCE(!found); | |
5014 | __lockdep_free_key_range(pf, key, 1); | |
5015 | call_rcu_zapped(pf); | |
8b39adbe BVA |
5016 | graph_unlock(); |
5017 | out_irq: | |
108c1485 BVA |
5018 | raw_local_irq_restore(flags); |
5019 | ||
5020 | /* Wait until is_dynamic_key() has finished accessing k->hash_entry. */ | |
5021 | synchronize_rcu(); | |
5022 | } | |
5023 | EXPORT_SYMBOL_GPL(lockdep_unregister_key); | |
5024 | ||
c3bc8fd6 | 5025 | void __init lockdep_init(void) |
fbb9ce95 IM |
5026 | { |
5027 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
5028 | ||
b0788caf | 5029 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
5030 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
5031 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 5032 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
5033 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
5034 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
5035 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
5036 | ||
09d75ecb | 5037 | printk(" memory used by lock dependency info: %zu kB\n", |
7ff8517e BVA |
5038 | (sizeof(lock_classes) + |
5039 | sizeof(classhash_table) + | |
5040 | sizeof(list_entries) + | |
ace35a7a | 5041 | sizeof(list_entries_in_use) + |
a0b0fd53 BVA |
5042 | sizeof(chainhash_table) + |
5043 | sizeof(delayed_free) | |
4dd861d6 | 5044 | #ifdef CONFIG_PROVE_LOCKING |
7ff8517e | 5045 | + sizeof(lock_cq) |
15ea86b5 | 5046 | + sizeof(lock_chains) |
de4643a7 | 5047 | + sizeof(lock_chains_in_use) |
15ea86b5 | 5048 | + sizeof(chain_hlocks) |
4dd861d6 | 5049 | #endif |
90629209 | 5050 | ) / 1024 |
4dd861d6 | 5051 | ); |
fbb9ce95 | 5052 | |
09d75ecb | 5053 | printk(" per task-struct memory footprint: %zu bytes\n", |
7ff8517e | 5054 | sizeof(((struct task_struct *)NULL)->held_locks)); |
fbb9ce95 IM |
5055 | } |
5056 | ||
fbb9ce95 IM |
5057 | static void |
5058 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 5059 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
5060 | { |
5061 | if (!debug_locks_off()) | |
5062 | return; | |
5063 | if (debug_locks_silent) | |
5064 | return; | |
5065 | ||
681fbec8 | 5066 | pr_warn("\n"); |
a5dd63ef PM |
5067 | pr_warn("=========================\n"); |
5068 | pr_warn("WARNING: held lock freed!\n"); | |
fbdc4b9a | 5069 | print_kernel_ident(); |
a5dd63ef | 5070 | pr_warn("-------------------------\n"); |
04860d48 | 5071 | pr_warn("%s/%d is freeing memory %px-%px, with a lock still held there!\n", |
ba25f9dc | 5072 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 5073 | print_lock(hlock); |
fbb9ce95 IM |
5074 | lockdep_print_held_locks(curr); |
5075 | ||
681fbec8 | 5076 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
5077 | dump_stack(); |
5078 | } | |
5079 | ||
54561783 ON |
5080 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
5081 | const void* lock_from, unsigned long lock_len) | |
5082 | { | |
5083 | return lock_from + lock_len <= mem_from || | |
5084 | mem_from + mem_len <= lock_from; | |
5085 | } | |
5086 | ||
fbb9ce95 IM |
5087 | /* |
5088 | * Called when kernel memory is freed (or unmapped), or if a lock | |
5089 | * is destroyed or reinitialized - this code checks whether there is | |
5090 | * any held lock in the memory range of <from> to <to>: | |
5091 | */ | |
5092 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
5093 | { | |
fbb9ce95 IM |
5094 | struct task_struct *curr = current; |
5095 | struct held_lock *hlock; | |
5096 | unsigned long flags; | |
5097 | int i; | |
5098 | ||
5099 | if (unlikely(!debug_locks)) | |
5100 | return; | |
5101 | ||
fcc784be | 5102 | raw_local_irq_save(flags); |
fbb9ce95 IM |
5103 | for (i = 0; i < curr->lockdep_depth; i++) { |
5104 | hlock = curr->held_locks + i; | |
5105 | ||
54561783 ON |
5106 | if (not_in_range(mem_from, mem_len, hlock->instance, |
5107 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
5108 | continue; |
5109 | ||
54561783 | 5110 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
5111 | break; |
5112 | } | |
fcc784be | 5113 | raw_local_irq_restore(flags); |
fbb9ce95 | 5114 | } |
ed07536e | 5115 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 5116 | |
1b1d2fb4 | 5117 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
5118 | { |
5119 | if (!debug_locks_off()) | |
5120 | return; | |
5121 | if (debug_locks_silent) | |
5122 | return; | |
5123 | ||
681fbec8 | 5124 | pr_warn("\n"); |
a5dd63ef PM |
5125 | pr_warn("====================================\n"); |
5126 | pr_warn("WARNING: %s/%d still has locks held!\n", | |
1b1d2fb4 | 5127 | current->comm, task_pid_nr(current)); |
fbdc4b9a | 5128 | print_kernel_ident(); |
a5dd63ef | 5129 | pr_warn("------------------------------------\n"); |
1b1d2fb4 | 5130 | lockdep_print_held_locks(current); |
681fbec8 | 5131 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
5132 | dump_stack(); |
5133 | } | |
5134 | ||
1b1d2fb4 | 5135 | void debug_check_no_locks_held(void) |
fbb9ce95 | 5136 | { |
1b1d2fb4 CC |
5137 | if (unlikely(current->lockdep_depth > 0)) |
5138 | print_held_locks_bug(); | |
fbb9ce95 | 5139 | } |
1b1d2fb4 | 5140 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 5141 | |
8dce7a9a | 5142 | #ifdef __KERNEL__ |
fbb9ce95 IM |
5143 | void debug_show_all_locks(void) |
5144 | { | |
5145 | struct task_struct *g, *p; | |
fbb9ce95 | 5146 | |
9c35dd7f | 5147 | if (unlikely(!debug_locks)) { |
681fbec8 | 5148 | pr_warn("INFO: lockdep is turned off.\n"); |
9c35dd7f JP |
5149 | return; |
5150 | } | |
681fbec8 | 5151 | pr_warn("\nShowing all locks held in the system:\n"); |
fbb9ce95 | 5152 | |
0f736a52 TH |
5153 | rcu_read_lock(); |
5154 | for_each_process_thread(g, p) { | |
0f736a52 TH |
5155 | if (!p->lockdep_depth) |
5156 | continue; | |
5157 | lockdep_print_held_locks(p); | |
88f1c87d | 5158 | touch_nmi_watchdog(); |
0f736a52 TH |
5159 | touch_all_softlockup_watchdogs(); |
5160 | } | |
5161 | rcu_read_unlock(); | |
fbb9ce95 | 5162 | |
681fbec8 | 5163 | pr_warn("\n"); |
a5dd63ef | 5164 | pr_warn("=============================================\n\n"); |
fbb9ce95 | 5165 | } |
fbb9ce95 | 5166 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 5167 | #endif |
fbb9ce95 | 5168 | |
82a1fcb9 IM |
5169 | /* |
5170 | * Careful: only use this function if you are sure that | |
5171 | * the task cannot run in parallel! | |
5172 | */ | |
f1b499f0 | 5173 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 5174 | { |
9c35dd7f JP |
5175 | if (unlikely(!debug_locks)) { |
5176 | printk("INFO: lockdep is turned off.\n"); | |
5177 | return; | |
5178 | } | |
fbb9ce95 IM |
5179 | lockdep_print_held_locks(task); |
5180 | } | |
fbb9ce95 | 5181 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 5182 | |
722a9f92 | 5183 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
5184 | { |
5185 | struct task_struct *curr = current; | |
5186 | ||
5187 | if (unlikely(curr->lockdep_depth)) { | |
5188 | if (!debug_locks_off()) | |
5189 | return; | |
681fbec8 | 5190 | pr_warn("\n"); |
a5dd63ef PM |
5191 | pr_warn("================================================\n"); |
5192 | pr_warn("WARNING: lock held when returning to user space!\n"); | |
fbdc4b9a | 5193 | print_kernel_ident(); |
a5dd63ef | 5194 | pr_warn("------------------------------------------------\n"); |
681fbec8 | 5195 | pr_warn("%s/%d is leaving the kernel with locks still held!\n", |
b351d164 PZ |
5196 | curr->comm, curr->pid); |
5197 | lockdep_print_held_locks(curr); | |
5198 | } | |
b09be676 BP |
5199 | |
5200 | /* | |
5201 | * The lock history for each syscall should be independent. So wipe the | |
5202 | * slate clean on return to userspace. | |
5203 | */ | |
f52be570 | 5204 | lockdep_invariant_state(false); |
b351d164 | 5205 | } |
0632eb3d | 5206 | |
b3fbab05 | 5207 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
5208 | { |
5209 | struct task_struct *curr = current; | |
5210 | ||
2b3fc35f | 5211 | /* Note: the following can be executed concurrently, so be careful. */ |
681fbec8 | 5212 | pr_warn("\n"); |
a5dd63ef PM |
5213 | pr_warn("=============================\n"); |
5214 | pr_warn("WARNING: suspicious RCU usage\n"); | |
fbdc4b9a | 5215 | print_kernel_ident(); |
a5dd63ef | 5216 | pr_warn("-----------------------------\n"); |
681fbec8 PM |
5217 | pr_warn("%s:%d %s!\n", file, line, s); |
5218 | pr_warn("\nother info that might help us debug this:\n\n"); | |
5219 | pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n", | |
c5fdcec9 PM |
5220 | !rcu_lockdep_current_cpu_online() |
5221 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 5222 | : !rcu_is_watching() |
c5fdcec9 PM |
5223 | ? "RCU used illegally from idle CPU!\n" |
5224 | : "", | |
5225 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
5226 | |
5227 | /* | |
5228 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
5229 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
5230 | * considers that CPU to be in an "extended quiescent state", | |
5231 | * which means that RCU will be completely ignoring that CPU. | |
5232 | * Therefore, rcu_read_lock() and friends have absolutely no | |
5233 | * effect on a CPU running in that state. In other words, even if | |
5234 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
5235 | * delete data structures out from under it. RCU really has no | |
5236 | * choice here: we need to keep an RCU-free window in idle where | |
5237 | * the CPU may possibly enter into low power mode. This way we can | |
5238 | * notice an extended quiescent state to other CPUs that started a grace | |
5239 | * period. Otherwise we would delay any grace period as long as we run | |
5240 | * in the idle task. | |
5241 | * | |
5242 | * So complain bitterly if someone does call rcu_read_lock(), | |
5243 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
5244 | */ | |
5c173eb8 | 5245 | if (!rcu_is_watching()) |
681fbec8 | 5246 | pr_warn("RCU used illegally from extended quiescent state!\n"); |
0464e937 | 5247 | |
0632eb3d | 5248 | lockdep_print_held_locks(curr); |
681fbec8 | 5249 | pr_warn("\nstack backtrace:\n"); |
0632eb3d PM |
5250 | dump_stack(); |
5251 | } | |
b3fbab05 | 5252 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |