]>
Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 | 8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
90eec103 | 9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
e6017571 | 31 | #include <linux/sched/clock.h> |
29930025 | 32 | #include <linux/sched/task.h> |
fbb9ce95 IM |
33 | #include <linux/delay.h> |
34 | #include <linux/module.h> | |
35 | #include <linux/proc_fs.h> | |
36 | #include <linux/seq_file.h> | |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/kallsyms.h> | |
39 | #include <linux/interrupt.h> | |
40 | #include <linux/stacktrace.h> | |
41 | #include <linux/debug_locks.h> | |
42 | #include <linux/irqflags.h> | |
99de055a | 43 | #include <linux/utsname.h> |
4b32d0a4 | 44 | #include <linux/hash.h> |
81d68a96 | 45 | #include <linux/ftrace.h> |
b4b136f4 | 46 | #include <linux/stringify.h> |
d588e461 | 47 | #include <linux/bitops.h> |
5a0e3ad6 | 48 | #include <linux/gfp.h> |
d3d03d4f | 49 | #include <linux/kmemcheck.h> |
e7904a28 | 50 | #include <linux/random.h> |
dfaaf3fa | 51 | #include <linux/jhash.h> |
af012961 | 52 | |
fbb9ce95 IM |
53 | #include <asm/sections.h> |
54 | ||
55 | #include "lockdep_internals.h" | |
56 | ||
a8d154b0 | 57 | #define CREATE_TRACE_POINTS |
67178767 | 58 | #include <trace/events/lock.h> |
a8d154b0 | 59 | |
f20786ff PZ |
60 | #ifdef CONFIG_PROVE_LOCKING |
61 | int prove_locking = 1; | |
62 | module_param(prove_locking, int, 0644); | |
63 | #else | |
64 | #define prove_locking 0 | |
65 | #endif | |
66 | ||
67 | #ifdef CONFIG_LOCK_STAT | |
68 | int lock_stat = 1; | |
69 | module_param(lock_stat, int, 0644); | |
70 | #else | |
71 | #define lock_stat 0 | |
72 | #endif | |
73 | ||
fbb9ce95 | 74 | /* |
74c383f1 IM |
75 | * lockdep_lock: protects the lockdep graph, the hashes and the |
76 | * class/list/hash allocators. | |
fbb9ce95 IM |
77 | * |
78 | * This is one of the rare exceptions where it's justified | |
79 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 80 | * code to recurse back into the lockdep code... |
fbb9ce95 | 81 | */ |
edc35bd7 | 82 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
83 | |
84 | static int graph_lock(void) | |
85 | { | |
0199c4e6 | 86 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
87 | /* |
88 | * Make sure that if another CPU detected a bug while | |
89 | * walking the graph we dont change it (while the other | |
90 | * CPU is busy printing out stuff with the graph lock | |
91 | * dropped already) | |
92 | */ | |
93 | if (!debug_locks) { | |
0199c4e6 | 94 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
95 | return 0; |
96 | } | |
bb065afb SR |
97 | /* prevent any recursions within lockdep from causing deadlocks */ |
98 | current->lockdep_recursion++; | |
74c383f1 IM |
99 | return 1; |
100 | } | |
101 | ||
102 | static inline int graph_unlock(void) | |
103 | { | |
0119fee4 PZ |
104 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
105 | /* | |
106 | * The lockdep graph lock isn't locked while we expect it to | |
107 | * be, we're confused now, bye! | |
108 | */ | |
381a2292 | 109 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 110 | } |
381a2292 | 111 | |
bb065afb | 112 | current->lockdep_recursion--; |
0199c4e6 | 113 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
114 | return 0; |
115 | } | |
116 | ||
117 | /* | |
118 | * Turn lock debugging off and return with 0 if it was off already, | |
119 | * and also release the graph lock: | |
120 | */ | |
121 | static inline int debug_locks_off_graph_unlock(void) | |
122 | { | |
123 | int ret = debug_locks_off(); | |
124 | ||
0199c4e6 | 125 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
126 | |
127 | return ret; | |
128 | } | |
fbb9ce95 | 129 | |
fbb9ce95 | 130 | unsigned long nr_list_entries; |
af012961 | 131 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 132 | |
fbb9ce95 IM |
133 | /* |
134 | * All data structures here are protected by the global debug_lock. | |
135 | * | |
136 | * Mutex key structs only get allocated, once during bootup, and never | |
137 | * get freed - this significantly simplifies the debugging code. | |
138 | */ | |
139 | unsigned long nr_lock_classes; | |
140 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
141 | ||
f82b217e DJ |
142 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
143 | { | |
144 | if (!hlock->class_idx) { | |
0119fee4 PZ |
145 | /* |
146 | * Someone passed in garbage, we give up. | |
147 | */ | |
f82b217e DJ |
148 | DEBUG_LOCKS_WARN_ON(1); |
149 | return NULL; | |
150 | } | |
151 | return lock_classes + hlock->class_idx - 1; | |
152 | } | |
153 | ||
f20786ff | 154 | #ifdef CONFIG_LOCK_STAT |
25528213 | 155 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
f20786ff | 156 | |
3365e779 PZ |
157 | static inline u64 lockstat_clock(void) |
158 | { | |
c676329a | 159 | return local_clock(); |
3365e779 PZ |
160 | } |
161 | ||
c7e78cff | 162 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
163 | { |
164 | int i; | |
165 | ||
c7e78cff PZ |
166 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
167 | if (points[i] == 0) { | |
168 | points[i] = ip; | |
f20786ff PZ |
169 | break; |
170 | } | |
c7e78cff | 171 | if (points[i] == ip) |
f20786ff PZ |
172 | break; |
173 | } | |
174 | ||
175 | return i; | |
176 | } | |
177 | ||
3365e779 | 178 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
179 | { |
180 | if (time > lt->max) | |
181 | lt->max = time; | |
182 | ||
109d71c6 | 183 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
184 | lt->min = time; |
185 | ||
186 | lt->total += time; | |
187 | lt->nr++; | |
188 | } | |
189 | ||
c46261de PZ |
190 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
191 | { | |
109d71c6 FR |
192 | if (!src->nr) |
193 | return; | |
194 | ||
195 | if (src->max > dst->max) | |
196 | dst->max = src->max; | |
197 | ||
198 | if (src->min < dst->min || !dst->nr) | |
199 | dst->min = src->min; | |
200 | ||
c46261de PZ |
201 | dst->total += src->total; |
202 | dst->nr += src->nr; | |
203 | } | |
204 | ||
205 | struct lock_class_stats lock_stats(struct lock_class *class) | |
206 | { | |
207 | struct lock_class_stats stats; | |
208 | int cpu, i; | |
209 | ||
210 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
211 | for_each_possible_cpu(cpu) { | |
212 | struct lock_class_stats *pcs = | |
1871e52c | 213 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
214 | |
215 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
216 | stats.contention_point[i] += pcs->contention_point[i]; | |
217 | ||
c7e78cff PZ |
218 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
219 | stats.contending_point[i] += pcs->contending_point[i]; | |
220 | ||
c46261de PZ |
221 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
222 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
223 | ||
224 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
225 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
226 | |
227 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
228 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
229 | } |
230 | ||
231 | return stats; | |
232 | } | |
233 | ||
234 | void clear_lock_stats(struct lock_class *class) | |
235 | { | |
236 | int cpu; | |
237 | ||
238 | for_each_possible_cpu(cpu) { | |
239 | struct lock_class_stats *cpu_stats = | |
1871e52c | 240 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
241 | |
242 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
243 | } | |
244 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 245 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
246 | } |
247 | ||
f20786ff PZ |
248 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
249 | { | |
1871e52c | 250 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
251 | } |
252 | ||
253 | static void put_lock_stats(struct lock_class_stats *stats) | |
254 | { | |
1871e52c | 255 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
256 | } |
257 | ||
258 | static void lock_release_holdtime(struct held_lock *hlock) | |
259 | { | |
260 | struct lock_class_stats *stats; | |
3365e779 | 261 | u64 holdtime; |
f20786ff PZ |
262 | |
263 | if (!lock_stat) | |
264 | return; | |
265 | ||
3365e779 | 266 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 267 | |
f82b217e | 268 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
269 | if (hlock->read) |
270 | lock_time_inc(&stats->read_holdtime, holdtime); | |
271 | else | |
272 | lock_time_inc(&stats->write_holdtime, holdtime); | |
273 | put_lock_stats(stats); | |
274 | } | |
275 | #else | |
276 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
277 | { | |
278 | } | |
279 | #endif | |
280 | ||
fbb9ce95 IM |
281 | /* |
282 | * We keep a global list of all lock classes. The list only grows, | |
283 | * never shrinks. The list is only accessed with the lockdep | |
284 | * spinlock lock held. | |
285 | */ | |
286 | LIST_HEAD(all_lock_classes); | |
287 | ||
288 | /* | |
289 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
290 | */ | |
291 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
292 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 293 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
294 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
295 | ||
a63f38cc | 296 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
fbb9ce95 | 297 | |
fbb9ce95 IM |
298 | /* |
299 | * We put the lock dependency chains into a hash-table as well, to cache | |
300 | * their existence: | |
301 | */ | |
302 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
303 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 304 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
305 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
306 | ||
a63f38cc | 307 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
fbb9ce95 IM |
308 | |
309 | /* | |
310 | * The hash key of the lock dependency chains is a hash itself too: | |
311 | * it's a hash of all locks taken up to that lock, including that lock. | |
312 | * It's a 64-bit hash, because it's important for the keys to be | |
313 | * unique. | |
314 | */ | |
dfaaf3fa PZ |
315 | static inline u64 iterate_chain_key(u64 key, u32 idx) |
316 | { | |
317 | u32 k0 = key, k1 = key >> 32; | |
318 | ||
319 | __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ | |
320 | ||
321 | return k0 | (u64)k1 << 32; | |
322 | } | |
fbb9ce95 | 323 | |
1d09daa5 | 324 | void lockdep_off(void) |
fbb9ce95 IM |
325 | { |
326 | current->lockdep_recursion++; | |
327 | } | |
fbb9ce95 IM |
328 | EXPORT_SYMBOL(lockdep_off); |
329 | ||
1d09daa5 | 330 | void lockdep_on(void) |
fbb9ce95 IM |
331 | { |
332 | current->lockdep_recursion--; | |
333 | } | |
fbb9ce95 IM |
334 | EXPORT_SYMBOL(lockdep_on); |
335 | ||
fbb9ce95 IM |
336 | /* |
337 | * Debugging switches: | |
338 | */ | |
339 | ||
340 | #define VERBOSE 0 | |
33e94e96 | 341 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
342 | |
343 | #if VERBOSE | |
344 | # define HARDIRQ_VERBOSE 1 | |
345 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 346 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
347 | #else |
348 | # define HARDIRQ_VERBOSE 0 | |
349 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 350 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
351 | #endif |
352 | ||
cf40bd16 | 353 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
354 | /* |
355 | * Quick filtering for interesting events: | |
356 | */ | |
357 | static int class_filter(struct lock_class *class) | |
358 | { | |
f9829cce AK |
359 | #if 0 |
360 | /* Example */ | |
fbb9ce95 | 361 | if (class->name_version == 1 && |
f9829cce | 362 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
363 | return 1; |
364 | if (class->name_version == 1 && | |
f9829cce | 365 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 366 | return 1; |
f9829cce | 367 | #endif |
a6640897 IM |
368 | /* Filter everything else. 1 would be to allow everything else */ |
369 | return 0; | |
fbb9ce95 IM |
370 | } |
371 | #endif | |
372 | ||
373 | static int verbose(struct lock_class *class) | |
374 | { | |
375 | #if VERBOSE | |
376 | return class_filter(class); | |
377 | #endif | |
378 | return 0; | |
379 | } | |
380 | ||
fbb9ce95 IM |
381 | /* |
382 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 383 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
384 | */ |
385 | unsigned long nr_stack_trace_entries; | |
386 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
387 | ||
2c522836 DJ |
388 | static void print_lockdep_off(const char *bug_msg) |
389 | { | |
390 | printk(KERN_DEBUG "%s\n", bug_msg); | |
391 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 392 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 393 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 394 | #endif |
2c522836 DJ |
395 | } |
396 | ||
fbb9ce95 IM |
397 | static int save_trace(struct stack_trace *trace) |
398 | { | |
399 | trace->nr_entries = 0; | |
400 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
401 | trace->entries = stack_trace + nr_stack_trace_entries; | |
402 | ||
5a1b3999 | 403 | trace->skip = 3; |
5a1b3999 | 404 | |
ab1b6f03 | 405 | save_stack_trace(trace); |
fbb9ce95 | 406 | |
4f84f433 PZ |
407 | /* |
408 | * Some daft arches put -1 at the end to indicate its a full trace. | |
409 | * | |
410 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
411 | * complete trace that maxes out the entries provided will be reported | |
412 | * as incomplete, friggin useless </rant> | |
413 | */ | |
ea5b41f9 TL |
414 | if (trace->nr_entries != 0 && |
415 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
416 | trace->nr_entries--; |
417 | ||
fbb9ce95 IM |
418 | trace->max_entries = trace->nr_entries; |
419 | ||
420 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 421 | |
4f84f433 | 422 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
423 | if (!debug_locks_off_graph_unlock()) |
424 | return 0; | |
425 | ||
2c522836 | 426 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
427 | dump_stack(); |
428 | ||
fbb9ce95 IM |
429 | return 0; |
430 | } | |
431 | ||
432 | return 1; | |
433 | } | |
434 | ||
435 | unsigned int nr_hardirq_chains; | |
436 | unsigned int nr_softirq_chains; | |
437 | unsigned int nr_process_chains; | |
438 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
439 | |
440 | #ifdef CONFIG_DEBUG_LOCKDEP | |
fbb9ce95 IM |
441 | /* |
442 | * Various lockdep statistics: | |
443 | */ | |
bd6d29c2 | 444 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
445 | #endif |
446 | ||
447 | /* | |
448 | * Locking printouts: | |
449 | */ | |
450 | ||
fabe9c42 | 451 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
452 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
453 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
454 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
455 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 456 | |
fbb9ce95 IM |
457 | static const char *usage_str[] = |
458 | { | |
fabe9c42 PZ |
459 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
460 | #include "lockdep_states.h" | |
461 | #undef LOCKDEP_STATE | |
462 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
463 | }; |
464 | ||
465 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
466 | { | |
ffb45122 | 467 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
468 | } |
469 | ||
3ff176ca | 470 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 471 | { |
3ff176ca PZ |
472 | return 1UL << bit; |
473 | } | |
fbb9ce95 | 474 | |
3ff176ca PZ |
475 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
476 | { | |
477 | char c = '.'; | |
478 | ||
479 | if (class->usage_mask & lock_flag(bit + 2)) | |
480 | c = '+'; | |
481 | if (class->usage_mask & lock_flag(bit)) { | |
482 | c = '-'; | |
483 | if (class->usage_mask & lock_flag(bit + 2)) | |
484 | c = '?'; | |
fbb9ce95 IM |
485 | } |
486 | ||
3ff176ca PZ |
487 | return c; |
488 | } | |
cf40bd16 | 489 | |
f510b233 | 490 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 491 | { |
f510b233 | 492 | int i = 0; |
cf40bd16 | 493 | |
f510b233 PZ |
494 | #define LOCKDEP_STATE(__STATE) \ |
495 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
496 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
497 | #include "lockdep_states.h" | |
498 | #undef LOCKDEP_STATE | |
499 | ||
500 | usage[i] = '\0'; | |
fbb9ce95 IM |
501 | } |
502 | ||
e5e78d08 | 503 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
504 | { |
505 | char str[KSYM_NAME_LEN]; | |
506 | const char *name; | |
507 | ||
fbb9ce95 IM |
508 | name = class->name; |
509 | if (!name) { | |
510 | name = __get_key_name(class->key, str); | |
f943fe0f | 511 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 512 | } else { |
f943fe0f | 513 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 514 | if (class->name_version > 1) |
f943fe0f | 515 | printk(KERN_CONT "#%d", class->name_version); |
fbb9ce95 | 516 | if (class->subclass) |
f943fe0f | 517 | printk(KERN_CONT "/%d", class->subclass); |
fbb9ce95 | 518 | } |
e5e78d08 SR |
519 | } |
520 | ||
521 | static void print_lock_name(struct lock_class *class) | |
522 | { | |
523 | char usage[LOCK_USAGE_CHARS]; | |
524 | ||
525 | get_usage_chars(class, usage); | |
526 | ||
f943fe0f | 527 | printk(KERN_CONT " ("); |
e5e78d08 | 528 | __print_lock_name(class); |
f943fe0f | 529 | printk(KERN_CONT "){%s}", usage); |
fbb9ce95 IM |
530 | } |
531 | ||
532 | static void print_lockdep_cache(struct lockdep_map *lock) | |
533 | { | |
534 | const char *name; | |
9281acea | 535 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
536 | |
537 | name = lock->name; | |
538 | if (!name) | |
539 | name = __get_key_name(lock->key->subkeys, str); | |
540 | ||
f943fe0f | 541 | printk(KERN_CONT "%s", name); |
fbb9ce95 IM |
542 | } |
543 | ||
544 | static void print_lock(struct held_lock *hlock) | |
545 | { | |
d7bc3197 PZ |
546 | /* |
547 | * We can be called locklessly through debug_show_all_locks() so be | |
548 | * extra careful, the hlock might have been released and cleared. | |
549 | */ | |
550 | unsigned int class_idx = hlock->class_idx; | |
551 | ||
552 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ | |
553 | barrier(); | |
554 | ||
555 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { | |
f943fe0f | 556 | printk(KERN_CONT "<RELEASED>\n"); |
d7bc3197 PZ |
557 | return; |
558 | } | |
559 | ||
560 | print_lock_name(lock_classes + class_idx - 1); | |
f943fe0f DV |
561 | printk(KERN_CONT ", at: [<%p>] %pS\n", |
562 | (void *)hlock->acquire_ip, (void *)hlock->acquire_ip); | |
fbb9ce95 IM |
563 | } |
564 | ||
565 | static void lockdep_print_held_locks(struct task_struct *curr) | |
566 | { | |
567 | int i, depth = curr->lockdep_depth; | |
568 | ||
569 | if (!depth) { | |
ba25f9dc | 570 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
571 | return; |
572 | } | |
573 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 574 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
575 | |
576 | for (i = 0; i < depth; i++) { | |
577 | printk(" #%d: ", i); | |
578 | print_lock(curr->held_locks + i); | |
579 | } | |
580 | } | |
fbb9ce95 | 581 | |
fbdc4b9a | 582 | static void print_kernel_ident(void) |
8e18257d | 583 | { |
fbdc4b9a | 584 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 585 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
586 | init_utsname()->version, |
587 | print_tainted()); | |
8e18257d PZ |
588 | } |
589 | ||
590 | static int very_verbose(struct lock_class *class) | |
591 | { | |
592 | #if VERY_VERBOSE | |
593 | return class_filter(class); | |
594 | #endif | |
595 | return 0; | |
596 | } | |
597 | ||
fbb9ce95 | 598 | /* |
8e18257d | 599 | * Is this the address of a static object: |
fbb9ce95 | 600 | */ |
8dce7a9a | 601 | #ifdef __KERNEL__ |
8e18257d | 602 | static int static_obj(void *obj) |
fbb9ce95 | 603 | { |
8e18257d PZ |
604 | unsigned long start = (unsigned long) &_stext, |
605 | end = (unsigned long) &_end, | |
606 | addr = (unsigned long) obj; | |
8e18257d | 607 | |
fbb9ce95 | 608 | /* |
8e18257d | 609 | * static variable? |
fbb9ce95 | 610 | */ |
8e18257d PZ |
611 | if ((addr >= start) && (addr < end)) |
612 | return 1; | |
fbb9ce95 | 613 | |
2a9ad18d MF |
614 | if (arch_is_kernel_data(addr)) |
615 | return 1; | |
616 | ||
fbb9ce95 | 617 | /* |
10fad5e4 | 618 | * in-kernel percpu var? |
fbb9ce95 | 619 | */ |
10fad5e4 TH |
620 | if (is_kernel_percpu_address(addr)) |
621 | return 1; | |
fbb9ce95 | 622 | |
8e18257d | 623 | /* |
10fad5e4 | 624 | * module static or percpu var? |
8e18257d | 625 | */ |
10fad5e4 | 626 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 627 | } |
8dce7a9a | 628 | #endif |
99de055a | 629 | |
fbb9ce95 | 630 | /* |
8e18257d PZ |
631 | * To make lock name printouts unique, we calculate a unique |
632 | * class->name_version generation counter: | |
fbb9ce95 | 633 | */ |
8e18257d | 634 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 635 | { |
8e18257d PZ |
636 | struct lock_class *class; |
637 | int count = 0; | |
fbb9ce95 | 638 | |
8e18257d | 639 | if (!new_class->name) |
fbb9ce95 IM |
640 | return 0; |
641 | ||
35a9393c | 642 | list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
643 | if (new_class->key - new_class->subclass == class->key) |
644 | return class->name_version; | |
645 | if (class->name && !strcmp(class->name, new_class->name)) | |
646 | count = max(count, class->name_version); | |
647 | } | |
fbb9ce95 | 648 | |
8e18257d | 649 | return count + 1; |
fbb9ce95 IM |
650 | } |
651 | ||
8e18257d PZ |
652 | /* |
653 | * Register a lock's class in the hash-table, if the class is not present | |
654 | * yet. Otherwise we look it up. We cache the result in the lock object | |
655 | * itself, so actual lookup of the hash should be once per lock object. | |
656 | */ | |
657 | static inline struct lock_class * | |
658 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 659 | { |
8e18257d | 660 | struct lockdep_subclass_key *key; |
a63f38cc | 661 | struct hlist_head *hash_head; |
8e18257d | 662 | struct lock_class *class; |
fbb9ce95 | 663 | |
4ba053c0 HM |
664 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
665 | debug_locks_off(); | |
666 | printk(KERN_ERR | |
667 | "BUG: looking up invalid subclass: %u\n", subclass); | |
668 | printk(KERN_ERR | |
669 | "turning off the locking correctness validator.\n"); | |
670 | dump_stack(); | |
671 | return NULL; | |
672 | } | |
673 | ||
8e18257d PZ |
674 | /* |
675 | * Static locks do not have their class-keys yet - for them the key | |
676 | * is the lock object itself: | |
677 | */ | |
678 | if (unlikely(!lock->key)) | |
679 | lock->key = (void *)lock; | |
fbb9ce95 | 680 | |
8e18257d PZ |
681 | /* |
682 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
683 | * lock_class_key variable is passed in through the mutex_init() | |
684 | * (or spin_lock_init()) call - which acts as the key. For static | |
685 | * locks we use the lock object itself as the key. | |
686 | */ | |
4b32d0a4 PZ |
687 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
688 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 689 | |
8e18257d | 690 | key = lock->key->subkeys + subclass; |
ca268c69 | 691 | |
8e18257d | 692 | hash_head = classhashentry(key); |
74c383f1 | 693 | |
8e18257d | 694 | /* |
35a9393c | 695 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 696 | */ |
35a9393c PZ |
697 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
698 | return NULL; | |
699 | ||
a63f38cc | 700 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
4b32d0a4 | 701 | if (class->key == key) { |
0119fee4 PZ |
702 | /* |
703 | * Huh! same key, different name? Did someone trample | |
704 | * on some memory? We're most confused. | |
705 | */ | |
4b32d0a4 | 706 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 707 | return class; |
4b32d0a4 PZ |
708 | } |
709 | } | |
fbb9ce95 | 710 | |
8e18257d | 711 | return NULL; |
fbb9ce95 IM |
712 | } |
713 | ||
714 | /* | |
8e18257d PZ |
715 | * Register a lock's class in the hash-table, if the class is not present |
716 | * yet. Otherwise we look it up. We cache the result in the lock object | |
717 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 718 | */ |
c003ed92 | 719 | static struct lock_class * |
8e18257d | 720 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
fbb9ce95 | 721 | { |
8e18257d | 722 | struct lockdep_subclass_key *key; |
a63f38cc | 723 | struct hlist_head *hash_head; |
8e18257d | 724 | struct lock_class *class; |
35a9393c PZ |
725 | |
726 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
727 | |
728 | class = look_up_lock_class(lock, subclass); | |
729 | if (likely(class)) | |
87cdee71 | 730 | goto out_set_class_cache; |
8e18257d PZ |
731 | |
732 | /* | |
733 | * Debug-check: all keys must be persistent! | |
734 | */ | |
735 | if (!static_obj(lock->key)) { | |
736 | debug_locks_off(); | |
737 | printk("INFO: trying to register non-static key.\n"); | |
738 | printk("the code is fine but needs lockdep annotation.\n"); | |
739 | printk("turning off the locking correctness validator.\n"); | |
740 | dump_stack(); | |
741 | ||
742 | return NULL; | |
743 | } | |
744 | ||
745 | key = lock->key->subkeys + subclass; | |
746 | hash_head = classhashentry(key); | |
747 | ||
8e18257d | 748 | if (!graph_lock()) { |
8e18257d PZ |
749 | return NULL; |
750 | } | |
751 | /* | |
752 | * We have to do the hash-walk again, to avoid races | |
753 | * with another CPU: | |
754 | */ | |
a63f38cc | 755 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
756 | if (class->key == key) |
757 | goto out_unlock_set; | |
35a9393c PZ |
758 | } |
759 | ||
8e18257d PZ |
760 | /* |
761 | * Allocate a new key from the static array, and add it to | |
762 | * the hash: | |
763 | */ | |
764 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
765 | if (!debug_locks_off_graph_unlock()) { | |
8e18257d PZ |
766 | return NULL; |
767 | } | |
8e18257d | 768 | |
2c522836 | 769 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 770 | dump_stack(); |
8e18257d PZ |
771 | return NULL; |
772 | } | |
773 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 774 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
775 | class->key = key; |
776 | class->name = lock->name; | |
777 | class->subclass = subclass; | |
778 | INIT_LIST_HEAD(&class->lock_entry); | |
779 | INIT_LIST_HEAD(&class->locks_before); | |
780 | INIT_LIST_HEAD(&class->locks_after); | |
781 | class->name_version = count_matching_names(class); | |
782 | /* | |
783 | * We use RCU's safe list-add method to make | |
784 | * parallel walking of the hash-list safe: | |
785 | */ | |
a63f38cc | 786 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
1481197b DF |
787 | /* |
788 | * Add it to the global list of classes: | |
789 | */ | |
790 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
791 | |
792 | if (verbose(class)) { | |
793 | graph_unlock(); | |
8e18257d PZ |
794 | |
795 | printk("\nnew class %p: %s", class->key, class->name); | |
796 | if (class->name_version > 1) | |
f943fe0f DV |
797 | printk(KERN_CONT "#%d", class->name_version); |
798 | printk(KERN_CONT "\n"); | |
8e18257d PZ |
799 | dump_stack(); |
800 | ||
8e18257d | 801 | if (!graph_lock()) { |
8e18257d PZ |
802 | return NULL; |
803 | } | |
804 | } | |
805 | out_unlock_set: | |
806 | graph_unlock(); | |
8e18257d | 807 | |
87cdee71 | 808 | out_set_class_cache: |
8e18257d | 809 | if (!subclass || force) |
62016250 HM |
810 | lock->class_cache[0] = class; |
811 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
812 | lock->class_cache[subclass] = class; | |
8e18257d | 813 | |
0119fee4 PZ |
814 | /* |
815 | * Hash collision, did we smoke some? We found a class with a matching | |
816 | * hash but the subclass -- which is hashed in -- didn't match. | |
817 | */ | |
8e18257d PZ |
818 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
819 | return NULL; | |
820 | ||
821 | return class; | |
822 | } | |
823 | ||
824 | #ifdef CONFIG_PROVE_LOCKING | |
825 | /* | |
826 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
827 | * with NULL on failure) | |
828 | */ | |
829 | static struct lock_list *alloc_list_entry(void) | |
830 | { | |
831 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
832 | if (!debug_locks_off_graph_unlock()) | |
833 | return NULL; | |
834 | ||
2c522836 | 835 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 836 | dump_stack(); |
8e18257d PZ |
837 | return NULL; |
838 | } | |
839 | return list_entries + nr_list_entries++; | |
840 | } | |
841 | ||
842 | /* | |
843 | * Add a new dependency to the head of the list: | |
844 | */ | |
83f06168 TE |
845 | static int add_lock_to_list(struct lock_class *this, struct list_head *head, |
846 | unsigned long ip, int distance, | |
847 | struct stack_trace *trace) | |
8e18257d PZ |
848 | { |
849 | struct lock_list *entry; | |
850 | /* | |
851 | * Lock not present yet - get a new dependency struct and | |
852 | * add it to the list: | |
853 | */ | |
854 | entry = alloc_list_entry(); | |
855 | if (!entry) | |
856 | return 0; | |
857 | ||
74870172 ZY |
858 | entry->class = this; |
859 | entry->distance = distance; | |
4726f2a6 | 860 | entry->trace = *trace; |
8e18257d | 861 | /* |
35a9393c PZ |
862 | * Both allocation and removal are done under the graph lock; but |
863 | * iteration is under RCU-sched; see look_up_lock_class() and | |
864 | * lockdep_free_key_range(). | |
8e18257d PZ |
865 | */ |
866 | list_add_tail_rcu(&entry->entry, head); | |
867 | ||
868 | return 1; | |
869 | } | |
870 | ||
98c33edd PZ |
871 | /* |
872 | * For good efficiency of modular, we use power of 2 | |
873 | */ | |
af012961 PZ |
874 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
875 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
876 | ||
98c33edd PZ |
877 | /* |
878 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
879 | * breadth-first search(BFS)algorithem, by which we can build |
880 | * the shortest path from the next lock to be acquired to the | |
881 | * previous held lock if there is a circular between them. | |
98c33edd | 882 | */ |
af012961 PZ |
883 | struct circular_queue { |
884 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
885 | unsigned int front, rear; | |
886 | }; | |
887 | ||
888 | static struct circular_queue lock_cq; | |
af012961 | 889 | |
12f3dfd0 | 890 | unsigned int max_bfs_queue_depth; |
af012961 | 891 | |
e351b660 ML |
892 | static unsigned int lockdep_dependency_gen_id; |
893 | ||
af012961 PZ |
894 | static inline void __cq_init(struct circular_queue *cq) |
895 | { | |
896 | cq->front = cq->rear = 0; | |
e351b660 | 897 | lockdep_dependency_gen_id++; |
af012961 PZ |
898 | } |
899 | ||
900 | static inline int __cq_empty(struct circular_queue *cq) | |
901 | { | |
902 | return (cq->front == cq->rear); | |
903 | } | |
904 | ||
905 | static inline int __cq_full(struct circular_queue *cq) | |
906 | { | |
907 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
908 | } | |
909 | ||
910 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
911 | { | |
912 | if (__cq_full(cq)) | |
913 | return -1; | |
914 | ||
915 | cq->element[cq->rear] = elem; | |
916 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
917 | return 0; | |
918 | } | |
919 | ||
920 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
921 | { | |
922 | if (__cq_empty(cq)) | |
923 | return -1; | |
924 | ||
925 | *elem = cq->element[cq->front]; | |
926 | cq->front = (cq->front + 1) & CQ_MASK; | |
927 | return 0; | |
928 | } | |
929 | ||
930 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
931 | { | |
932 | return (cq->rear - cq->front) & CQ_MASK; | |
933 | } | |
934 | ||
935 | static inline void mark_lock_accessed(struct lock_list *lock, | |
936 | struct lock_list *parent) | |
937 | { | |
938 | unsigned long nr; | |
98c33edd | 939 | |
af012961 | 940 | nr = lock - list_entries; |
0119fee4 | 941 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 942 | lock->parent = parent; |
e351b660 | 943 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
944 | } |
945 | ||
946 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
947 | { | |
948 | unsigned long nr; | |
98c33edd | 949 | |
af012961 | 950 | nr = lock - list_entries; |
0119fee4 | 951 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 952 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
953 | } |
954 | ||
955 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
956 | { | |
957 | return child->parent; | |
958 | } | |
959 | ||
960 | static inline int get_lock_depth(struct lock_list *child) | |
961 | { | |
962 | int depth = 0; | |
963 | struct lock_list *parent; | |
964 | ||
965 | while ((parent = get_lock_parent(child))) { | |
966 | child = parent; | |
967 | depth++; | |
968 | } | |
969 | return depth; | |
970 | } | |
971 | ||
9e2d551e | 972 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
973 | void *data, |
974 | int (*match)(struct lock_list *entry, void *data), | |
975 | struct lock_list **target_entry, | |
976 | int forward) | |
c94aa5ca ML |
977 | { |
978 | struct lock_list *entry; | |
d588e461 | 979 | struct list_head *head; |
c94aa5ca ML |
980 | struct circular_queue *cq = &lock_cq; |
981 | int ret = 1; | |
982 | ||
9e2d551e | 983 | if (match(source_entry, data)) { |
c94aa5ca ML |
984 | *target_entry = source_entry; |
985 | ret = 0; | |
986 | goto exit; | |
987 | } | |
988 | ||
d588e461 ML |
989 | if (forward) |
990 | head = &source_entry->class->locks_after; | |
991 | else | |
992 | head = &source_entry->class->locks_before; | |
993 | ||
994 | if (list_empty(head)) | |
995 | goto exit; | |
996 | ||
997 | __cq_init(cq); | |
c94aa5ca ML |
998 | __cq_enqueue(cq, (unsigned long)source_entry); |
999 | ||
1000 | while (!__cq_empty(cq)) { | |
1001 | struct lock_list *lock; | |
c94aa5ca ML |
1002 | |
1003 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1004 | ||
1005 | if (!lock->class) { | |
1006 | ret = -2; | |
1007 | goto exit; | |
1008 | } | |
1009 | ||
1010 | if (forward) | |
1011 | head = &lock->class->locks_after; | |
1012 | else | |
1013 | head = &lock->class->locks_before; | |
1014 | ||
35a9393c PZ |
1015 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1016 | ||
1017 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1018 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1019 | unsigned int cq_depth; |
c94aa5ca | 1020 | mark_lock_accessed(entry, lock); |
9e2d551e | 1021 | if (match(entry, data)) { |
c94aa5ca ML |
1022 | *target_entry = entry; |
1023 | ret = 0; | |
1024 | goto exit; | |
1025 | } | |
1026 | ||
1027 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1028 | ret = -1; | |
1029 | goto exit; | |
1030 | } | |
12f3dfd0 ML |
1031 | cq_depth = __cq_get_elem_count(cq); |
1032 | if (max_bfs_queue_depth < cq_depth) | |
1033 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1034 | } |
1035 | } | |
1036 | } | |
1037 | exit: | |
1038 | return ret; | |
1039 | } | |
1040 | ||
d7aaba14 | 1041 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1042 | void *data, |
1043 | int (*match)(struct lock_list *entry, void *data), | |
1044 | struct lock_list **target_entry) | |
c94aa5ca | 1045 | { |
9e2d551e | 1046 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1047 | |
1048 | } | |
1049 | ||
d7aaba14 | 1050 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1051 | void *data, |
1052 | int (*match)(struct lock_list *entry, void *data), | |
1053 | struct lock_list **target_entry) | |
c94aa5ca | 1054 | { |
9e2d551e | 1055 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1056 | |
1057 | } | |
1058 | ||
8e18257d PZ |
1059 | /* |
1060 | * Recursive, forwards-direction lock-dependency checking, used for | |
1061 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1062 | * checking. | |
8e18257d | 1063 | */ |
8e18257d PZ |
1064 | |
1065 | /* | |
1066 | * Print a dependency chain entry (this is only done when a deadlock | |
1067 | * has been detected): | |
1068 | */ | |
1069 | static noinline int | |
24208ca7 | 1070 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1071 | { |
1072 | if (debug_locks_silent) | |
1073 | return 0; | |
1074 | printk("\n-> #%u", depth); | |
1075 | print_lock_name(target->class); | |
f943fe0f | 1076 | printk(KERN_CONT ":\n"); |
8e18257d PZ |
1077 | print_stack_trace(&target->trace, 6); |
1078 | ||
1079 | return 0; | |
1080 | } | |
1081 | ||
f4185812 SR |
1082 | static void |
1083 | print_circular_lock_scenario(struct held_lock *src, | |
1084 | struct held_lock *tgt, | |
1085 | struct lock_list *prt) | |
1086 | { | |
1087 | struct lock_class *source = hlock_class(src); | |
1088 | struct lock_class *target = hlock_class(tgt); | |
1089 | struct lock_class *parent = prt->class; | |
1090 | ||
1091 | /* | |
1092 | * A direct locking problem where unsafe_class lock is taken | |
1093 | * directly by safe_class lock, then all we need to show | |
1094 | * is the deadlock scenario, as it is obvious that the | |
1095 | * unsafe lock is taken under the safe lock. | |
1096 | * | |
1097 | * But if there is a chain instead, where the safe lock takes | |
1098 | * an intermediate lock (middle_class) where this lock is | |
1099 | * not the same as the safe lock, then the lock chain is | |
1100 | * used to describe the problem. Otherwise we would need | |
1101 | * to show a different CPU case for each link in the chain | |
1102 | * from the safe_class lock to the unsafe_class lock. | |
1103 | */ | |
1104 | if (parent != source) { | |
1105 | printk("Chain exists of:\n "); | |
1106 | __print_lock_name(source); | |
f943fe0f | 1107 | printk(KERN_CONT " --> "); |
f4185812 | 1108 | __print_lock_name(parent); |
f943fe0f | 1109 | printk(KERN_CONT " --> "); |
f4185812 | 1110 | __print_lock_name(target); |
f943fe0f | 1111 | printk(KERN_CONT "\n\n"); |
f4185812 SR |
1112 | } |
1113 | ||
1114 | printk(" Possible unsafe locking scenario:\n\n"); | |
1115 | printk(" CPU0 CPU1\n"); | |
1116 | printk(" ---- ----\n"); | |
1117 | printk(" lock("); | |
1118 | __print_lock_name(target); | |
f943fe0f | 1119 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1120 | printk(" lock("); |
1121 | __print_lock_name(parent); | |
f943fe0f | 1122 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1123 | printk(" lock("); |
1124 | __print_lock_name(target); | |
f943fe0f | 1125 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1126 | printk(" lock("); |
1127 | __print_lock_name(source); | |
f943fe0f | 1128 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1129 | printk("\n *** DEADLOCK ***\n\n"); |
1130 | } | |
1131 | ||
8e18257d PZ |
1132 | /* |
1133 | * When a circular dependency is detected, print the | |
1134 | * header first: | |
1135 | */ | |
1136 | static noinline int | |
db0002a3 ML |
1137 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1138 | struct held_lock *check_src, | |
1139 | struct held_lock *check_tgt) | |
8e18257d PZ |
1140 | { |
1141 | struct task_struct *curr = current; | |
1142 | ||
c94aa5ca | 1143 | if (debug_locks_silent) |
8e18257d PZ |
1144 | return 0; |
1145 | ||
b3fbab05 PM |
1146 | printk("\n"); |
1147 | printk("======================================================\n"); | |
1148 | printk("[ INFO: possible circular locking dependency detected ]\n"); | |
fbdc4b9a | 1149 | print_kernel_ident(); |
b3fbab05 | 1150 | printk("-------------------------------------------------------\n"); |
8e18257d | 1151 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1152 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1153 | print_lock(check_src); |
8e18257d | 1154 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1155 | print_lock(check_tgt); |
8e18257d PZ |
1156 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1157 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1158 | ||
1159 | print_circular_bug_entry(entry, depth); | |
1160 | ||
1161 | return 0; | |
1162 | } | |
1163 | ||
9e2d551e ML |
1164 | static inline int class_equal(struct lock_list *entry, void *data) |
1165 | { | |
1166 | return entry->class == data; | |
1167 | } | |
1168 | ||
db0002a3 ML |
1169 | static noinline int print_circular_bug(struct lock_list *this, |
1170 | struct lock_list *target, | |
1171 | struct held_lock *check_src, | |
1172 | struct held_lock *check_tgt) | |
8e18257d PZ |
1173 | { |
1174 | struct task_struct *curr = current; | |
c94aa5ca | 1175 | struct lock_list *parent; |
f4185812 | 1176 | struct lock_list *first_parent; |
24208ca7 | 1177 | int depth; |
8e18257d | 1178 | |
c94aa5ca | 1179 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1180 | return 0; |
1181 | ||
db0002a3 | 1182 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1183 | return 0; |
1184 | ||
c94aa5ca ML |
1185 | depth = get_lock_depth(target); |
1186 | ||
db0002a3 | 1187 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1188 | |
1189 | parent = get_lock_parent(target); | |
f4185812 | 1190 | first_parent = parent; |
c94aa5ca ML |
1191 | |
1192 | while (parent) { | |
1193 | print_circular_bug_entry(parent, --depth); | |
1194 | parent = get_lock_parent(parent); | |
1195 | } | |
8e18257d PZ |
1196 | |
1197 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1198 | print_circular_lock_scenario(check_src, check_tgt, |
1199 | first_parent); | |
1200 | ||
8e18257d PZ |
1201 | lockdep_print_held_locks(curr); |
1202 | ||
1203 | printk("\nstack backtrace:\n"); | |
1204 | dump_stack(); | |
1205 | ||
1206 | return 0; | |
1207 | } | |
1208 | ||
db0002a3 ML |
1209 | static noinline int print_bfs_bug(int ret) |
1210 | { | |
1211 | if (!debug_locks_off_graph_unlock()) | |
1212 | return 0; | |
1213 | ||
0119fee4 PZ |
1214 | /* |
1215 | * Breadth-first-search failed, graph got corrupted? | |
1216 | */ | |
db0002a3 ML |
1217 | WARN(1, "lockdep bfs error:%d\n", ret); |
1218 | ||
1219 | return 0; | |
1220 | } | |
1221 | ||
ef681026 | 1222 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1223 | { |
ef681026 ML |
1224 | (*(unsigned long *)data)++; |
1225 | return 0; | |
1226 | } | |
419ca3f1 | 1227 | |
5216d530 | 1228 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1229 | { |
1230 | unsigned long count = 0; | |
1231 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1232 | |
ef681026 | 1233 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1234 | |
ef681026 | 1235 | return count; |
419ca3f1 | 1236 | } |
419ca3f1 DM |
1237 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1238 | { | |
1239 | unsigned long ret, flags; | |
ef681026 ML |
1240 | struct lock_list this; |
1241 | ||
1242 | this.parent = NULL; | |
1243 | this.class = class; | |
419ca3f1 DM |
1244 | |
1245 | local_irq_save(flags); | |
0199c4e6 | 1246 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1247 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1248 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1249 | local_irq_restore(flags); |
1250 | ||
1251 | return ret; | |
1252 | } | |
1253 | ||
5216d530 | 1254 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1255 | { |
ef681026 ML |
1256 | unsigned long count = 0; |
1257 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1258 | |
ef681026 | 1259 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1260 | |
ef681026 | 1261 | return count; |
419ca3f1 DM |
1262 | } |
1263 | ||
1264 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1265 | { | |
1266 | unsigned long ret, flags; | |
ef681026 ML |
1267 | struct lock_list this; |
1268 | ||
1269 | this.parent = NULL; | |
1270 | this.class = class; | |
419ca3f1 DM |
1271 | |
1272 | local_irq_save(flags); | |
0199c4e6 | 1273 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1274 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1275 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1276 | local_irq_restore(flags); |
1277 | ||
1278 | return ret; | |
1279 | } | |
1280 | ||
8e18257d PZ |
1281 | /* |
1282 | * Prove that the dependency graph starting at <entry> can not | |
1283 | * lead to <target>. Print an error and return 0 if it does. | |
1284 | */ | |
1285 | static noinline int | |
db0002a3 ML |
1286 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1287 | struct lock_list **target_entry) | |
8e18257d | 1288 | { |
db0002a3 | 1289 | int result; |
8e18257d | 1290 | |
bd6d29c2 | 1291 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1292 | |
d7aaba14 | 1293 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1294 | |
db0002a3 ML |
1295 | return result; |
1296 | } | |
c94aa5ca | 1297 | |
81d68a96 | 1298 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1299 | /* |
1300 | * Forwards and backwards subgraph searching, for the purposes of | |
1301 | * proving that two subgraphs can be connected by a new dependency | |
1302 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1303 | */ | |
fbb9ce95 | 1304 | |
d7aaba14 ML |
1305 | static inline int usage_match(struct lock_list *entry, void *bit) |
1306 | { | |
1307 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1308 | } | |
1309 | ||
1310 | ||
1311 | ||
fbb9ce95 IM |
1312 | /* |
1313 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1314 | * at @root->class that matches @bit. |
fbb9ce95 | 1315 | * |
d7aaba14 ML |
1316 | * Return 0 if such a node exists in the subgraph, and put that node |
1317 | * into *@target_entry. | |
fbb9ce95 | 1318 | * |
d7aaba14 ML |
1319 | * Return 1 otherwise and keep *@target_entry unchanged. |
1320 | * Return <0 on error. | |
fbb9ce95 | 1321 | */ |
d7aaba14 ML |
1322 | static int |
1323 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1324 | struct lock_list **target_entry) | |
fbb9ce95 | 1325 | { |
d7aaba14 | 1326 | int result; |
fbb9ce95 | 1327 | |
bd6d29c2 | 1328 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1329 | |
d7aaba14 ML |
1330 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1331 | ||
1332 | return result; | |
fbb9ce95 IM |
1333 | } |
1334 | ||
1335 | /* | |
1336 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1337 | * at @root->class that matches @bit. |
fbb9ce95 | 1338 | * |
d7aaba14 ML |
1339 | * Return 0 if such a node exists in the subgraph, and put that node |
1340 | * into *@target_entry. | |
fbb9ce95 | 1341 | * |
d7aaba14 ML |
1342 | * Return 1 otherwise and keep *@target_entry unchanged. |
1343 | * Return <0 on error. | |
fbb9ce95 | 1344 | */ |
d7aaba14 ML |
1345 | static int |
1346 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1347 | struct lock_list **target_entry) | |
fbb9ce95 | 1348 | { |
d7aaba14 | 1349 | int result; |
fbb9ce95 | 1350 | |
bd6d29c2 | 1351 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1352 | |
d7aaba14 | 1353 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1354 | |
d7aaba14 | 1355 | return result; |
fbb9ce95 IM |
1356 | } |
1357 | ||
af012961 PZ |
1358 | static void print_lock_class_header(struct lock_class *class, int depth) |
1359 | { | |
1360 | int bit; | |
1361 | ||
1362 | printk("%*s->", depth, ""); | |
1363 | print_lock_name(class); | |
f943fe0f DV |
1364 | printk(KERN_CONT " ops: %lu", class->ops); |
1365 | printk(KERN_CONT " {\n"); | |
af012961 PZ |
1366 | |
1367 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1368 | if (class->usage_mask & (1 << bit)) { | |
1369 | int len = depth; | |
1370 | ||
1371 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
f943fe0f | 1372 | len += printk(KERN_CONT " at:\n"); |
af012961 PZ |
1373 | print_stack_trace(class->usage_traces + bit, len); |
1374 | } | |
1375 | } | |
1376 | printk("%*s }\n", depth, ""); | |
1377 | ||
f943fe0f DV |
1378 | printk("%*s ... key at: [<%p>] %pS\n", |
1379 | depth, "", class->key, class->key); | |
af012961 PZ |
1380 | } |
1381 | ||
1382 | /* | |
1383 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1384 | */ | |
1385 | static void __used | |
1386 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1387 | struct lock_list *root) | |
1388 | { | |
1389 | struct lock_list *entry = leaf; | |
1390 | int depth; | |
1391 | ||
1392 | /*compute depth from generated tree by BFS*/ | |
1393 | depth = get_lock_depth(leaf); | |
1394 | ||
1395 | do { | |
1396 | print_lock_class_header(entry->class, depth); | |
1397 | printk("%*s ... acquired at:\n", depth, ""); | |
1398 | print_stack_trace(&entry->trace, 2); | |
1399 | printk("\n"); | |
1400 | ||
1401 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1402 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1403 | break; |
1404 | } | |
1405 | ||
1406 | entry = get_lock_parent(entry); | |
1407 | depth--; | |
1408 | } while (entry && (depth >= 0)); | |
1409 | ||
1410 | return; | |
1411 | } | |
d7aaba14 | 1412 | |
3003eba3 SR |
1413 | static void |
1414 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1415 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1416 | struct lock_class *prev_class, |
1417 | struct lock_class *next_class) | |
3003eba3 SR |
1418 | { |
1419 | struct lock_class *safe_class = safe_entry->class; | |
1420 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1421 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1422 | |
1423 | if (middle_class == safe_class) | |
dad3d743 | 1424 | middle_class = next_class; |
3003eba3 SR |
1425 | |
1426 | /* | |
1427 | * A direct locking problem where unsafe_class lock is taken | |
1428 | * directly by safe_class lock, then all we need to show | |
1429 | * is the deadlock scenario, as it is obvious that the | |
1430 | * unsafe lock is taken under the safe lock. | |
1431 | * | |
1432 | * But if there is a chain instead, where the safe lock takes | |
1433 | * an intermediate lock (middle_class) where this lock is | |
1434 | * not the same as the safe lock, then the lock chain is | |
1435 | * used to describe the problem. Otherwise we would need | |
1436 | * to show a different CPU case for each link in the chain | |
1437 | * from the safe_class lock to the unsafe_class lock. | |
1438 | */ | |
1439 | if (middle_class != unsafe_class) { | |
1440 | printk("Chain exists of:\n "); | |
1441 | __print_lock_name(safe_class); | |
f943fe0f | 1442 | printk(KERN_CONT " --> "); |
3003eba3 | 1443 | __print_lock_name(middle_class); |
f943fe0f | 1444 | printk(KERN_CONT " --> "); |
3003eba3 | 1445 | __print_lock_name(unsafe_class); |
f943fe0f | 1446 | printk(KERN_CONT "\n\n"); |
3003eba3 SR |
1447 | } |
1448 | ||
1449 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1450 | printk(" CPU0 CPU1\n"); | |
1451 | printk(" ---- ----\n"); | |
1452 | printk(" lock("); | |
1453 | __print_lock_name(unsafe_class); | |
f943fe0f | 1454 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1455 | printk(" local_irq_disable();\n"); |
1456 | printk(" lock("); | |
1457 | __print_lock_name(safe_class); | |
f943fe0f | 1458 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1459 | printk(" lock("); |
1460 | __print_lock_name(middle_class); | |
f943fe0f | 1461 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1462 | printk(" <Interrupt>\n"); |
1463 | printk(" lock("); | |
1464 | __print_lock_name(safe_class); | |
f943fe0f | 1465 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1466 | printk("\n *** DEADLOCK ***\n\n"); |
1467 | } | |
1468 | ||
fbb9ce95 IM |
1469 | static int |
1470 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1471 | struct lock_list *prev_root, |
1472 | struct lock_list *next_root, | |
1473 | struct lock_list *backwards_entry, | |
1474 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1475 | struct held_lock *prev, |
1476 | struct held_lock *next, | |
1477 | enum lock_usage_bit bit1, | |
1478 | enum lock_usage_bit bit2, | |
1479 | const char *irqclass) | |
1480 | { | |
74c383f1 | 1481 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1482 | return 0; |
1483 | ||
b3fbab05 PM |
1484 | printk("\n"); |
1485 | printk("======================================================\n"); | |
1486 | printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
fbb9ce95 | 1487 | irqclass, irqclass); |
fbdc4b9a | 1488 | print_kernel_ident(); |
b3fbab05 | 1489 | printk("------------------------------------------------------\n"); |
fbb9ce95 | 1490 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1491 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1492 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1493 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1494 | curr->hardirqs_enabled, | |
1495 | curr->softirqs_enabled); | |
1496 | print_lock(next); | |
1497 | ||
1498 | printk("\nand this task is already holding:\n"); | |
1499 | print_lock(prev); | |
1500 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1501 | print_lock_name(hlock_class(prev)); |
f943fe0f | 1502 | printk(KERN_CONT " ->"); |
f82b217e | 1503 | print_lock_name(hlock_class(next)); |
f943fe0f | 1504 | printk(KERN_CONT "\n"); |
fbb9ce95 IM |
1505 | |
1506 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1507 | irqclass); | |
24208ca7 | 1508 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1509 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1510 | ||
24208ca7 | 1511 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1512 | |
1513 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1514 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1515 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1516 | printk("..."); | |
1517 | ||
24208ca7 | 1518 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1519 | |
1520 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1521 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1522 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1523 | |
fbb9ce95 IM |
1524 | lockdep_print_held_locks(curr); |
1525 | ||
f943fe0f | 1526 | printk("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass); |
24208ca7 ML |
1527 | if (!save_trace(&prev_root->trace)) |
1528 | return 0; | |
1529 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1530 | |
24208ca7 ML |
1531 | printk("\nthe dependencies between the lock to be acquired"); |
1532 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1533 | if (!save_trace(&next_root->trace)) | |
1534 | return 0; | |
1535 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1536 | |
1537 | printk("\nstack backtrace:\n"); | |
1538 | dump_stack(); | |
1539 | ||
1540 | return 0; | |
1541 | } | |
1542 | ||
1543 | static int | |
1544 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1545 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1546 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1547 | { | |
1548 | int ret; | |
24208ca7 | 1549 | struct lock_list this, that; |
d7aaba14 | 1550 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1551 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1552 | |
1553 | this.parent = NULL; | |
1554 | ||
1555 | this.class = hlock_class(prev); | |
1556 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1557 | if (ret < 0) |
1558 | return print_bfs_bug(ret); | |
1559 | if (ret == 1) | |
1560 | return ret; | |
d7aaba14 | 1561 | |
24208ca7 ML |
1562 | that.parent = NULL; |
1563 | that.class = hlock_class(next); | |
1564 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1565 | if (ret < 0) |
1566 | return print_bfs_bug(ret); | |
1567 | if (ret == 1) | |
1568 | return ret; | |
fbb9ce95 | 1569 | |
24208ca7 ML |
1570 | return print_bad_irq_dependency(curr, &this, &that, |
1571 | target_entry, target_entry1, | |
1572 | prev, next, | |
fbb9ce95 IM |
1573 | bit_backwards, bit_forwards, irqclass); |
1574 | } | |
1575 | ||
4f367d8a PZ |
1576 | static const char *state_names[] = { |
1577 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1578 | __stringify(__STATE), |
4f367d8a PZ |
1579 | #include "lockdep_states.h" |
1580 | #undef LOCKDEP_STATE | |
1581 | }; | |
1582 | ||
1583 | static const char *state_rnames[] = { | |
1584 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1585 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1586 | #include "lockdep_states.h" |
1587 | #undef LOCKDEP_STATE | |
1588 | }; | |
1589 | ||
1590 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1591 | { |
4f367d8a PZ |
1592 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1593 | } | |
8e18257d | 1594 | |
4f367d8a PZ |
1595 | static int exclusive_bit(int new_bit) |
1596 | { | |
8e18257d | 1597 | /* |
4f367d8a PZ |
1598 | * USED_IN |
1599 | * USED_IN_READ | |
1600 | * ENABLED | |
1601 | * ENABLED_READ | |
1602 | * | |
1603 | * bit 0 - write/read | |
1604 | * bit 1 - used_in/enabled | |
1605 | * bit 2+ state | |
8e18257d | 1606 | */ |
4f367d8a PZ |
1607 | |
1608 | int state = new_bit & ~3; | |
1609 | int dir = new_bit & 2; | |
8e18257d PZ |
1610 | |
1611 | /* | |
4f367d8a | 1612 | * keep state, bit flip the direction and strip read. |
8e18257d | 1613 | */ |
4f367d8a PZ |
1614 | return state | (dir ^ 2); |
1615 | } | |
1616 | ||
1617 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1618 | struct held_lock *next, enum lock_usage_bit bit) | |
1619 | { | |
8e18257d | 1620 | /* |
4f367d8a PZ |
1621 | * Prove that the new dependency does not connect a hardirq-safe |
1622 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1623 | * the backwards-subgraph starting at <prev>, and the |
1624 | * forwards-subgraph starting at <next>: | |
1625 | */ | |
4f367d8a PZ |
1626 | if (!check_usage(curr, prev, next, bit, |
1627 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1628 | return 0; |
1629 | ||
4f367d8a PZ |
1630 | bit++; /* _READ */ |
1631 | ||
cf40bd16 | 1632 | /* |
4f367d8a PZ |
1633 | * Prove that the new dependency does not connect a hardirq-safe-read |
1634 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1635 | * the backwards-subgraph starting at <prev>, and the |
1636 | * forwards-subgraph starting at <next>: | |
1637 | */ | |
4f367d8a PZ |
1638 | if (!check_usage(curr, prev, next, bit, |
1639 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1640 | return 0; |
1641 | ||
4f367d8a PZ |
1642 | return 1; |
1643 | } | |
1644 | ||
1645 | static int | |
1646 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1647 | struct held_lock *next) | |
1648 | { | |
1649 | #define LOCKDEP_STATE(__STATE) \ | |
1650 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1651 | return 0; |
4f367d8a PZ |
1652 | #include "lockdep_states.h" |
1653 | #undef LOCKDEP_STATE | |
cf40bd16 | 1654 | |
8e18257d PZ |
1655 | return 1; |
1656 | } | |
1657 | ||
1658 | static void inc_chains(void) | |
1659 | { | |
1660 | if (current->hardirq_context) | |
1661 | nr_hardirq_chains++; | |
1662 | else { | |
1663 | if (current->softirq_context) | |
1664 | nr_softirq_chains++; | |
1665 | else | |
1666 | nr_process_chains++; | |
1667 | } | |
1668 | } | |
1669 | ||
1670 | #else | |
1671 | ||
1672 | static inline int | |
1673 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1674 | struct held_lock *next) | |
1675 | { | |
1676 | return 1; | |
1677 | } | |
1678 | ||
1679 | static inline void inc_chains(void) | |
1680 | { | |
1681 | nr_process_chains++; | |
1682 | } | |
1683 | ||
fbb9ce95 IM |
1684 | #endif |
1685 | ||
48702ecf SR |
1686 | static void |
1687 | print_deadlock_scenario(struct held_lock *nxt, | |
1688 | struct held_lock *prv) | |
1689 | { | |
1690 | struct lock_class *next = hlock_class(nxt); | |
1691 | struct lock_class *prev = hlock_class(prv); | |
1692 | ||
1693 | printk(" Possible unsafe locking scenario:\n\n"); | |
1694 | printk(" CPU0\n"); | |
1695 | printk(" ----\n"); | |
1696 | printk(" lock("); | |
1697 | __print_lock_name(prev); | |
f943fe0f | 1698 | printk(KERN_CONT ");\n"); |
48702ecf SR |
1699 | printk(" lock("); |
1700 | __print_lock_name(next); | |
f943fe0f | 1701 | printk(KERN_CONT ");\n"); |
48702ecf SR |
1702 | printk("\n *** DEADLOCK ***\n\n"); |
1703 | printk(" May be due to missing lock nesting notation\n\n"); | |
1704 | } | |
1705 | ||
fbb9ce95 IM |
1706 | static int |
1707 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1708 | struct held_lock *next) | |
1709 | { | |
74c383f1 | 1710 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1711 | return 0; |
1712 | ||
b3fbab05 PM |
1713 | printk("\n"); |
1714 | printk("=============================================\n"); | |
1715 | printk("[ INFO: possible recursive locking detected ]\n"); | |
fbdc4b9a | 1716 | print_kernel_ident(); |
b3fbab05 | 1717 | printk("---------------------------------------------\n"); |
fbb9ce95 | 1718 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1719 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1720 | print_lock(next); |
1721 | printk("\nbut task is already holding lock:\n"); | |
1722 | print_lock(prev); | |
1723 | ||
1724 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1725 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1726 | lockdep_print_held_locks(curr); |
1727 | ||
1728 | printk("\nstack backtrace:\n"); | |
1729 | dump_stack(); | |
1730 | ||
1731 | return 0; | |
1732 | } | |
1733 | ||
1734 | /* | |
1735 | * Check whether we are holding such a class already. | |
1736 | * | |
1737 | * (Note that this has to be done separately, because the graph cannot | |
1738 | * detect such classes of deadlocks.) | |
1739 | * | |
1740 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1741 | */ | |
1742 | static int | |
1743 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1744 | struct lockdep_map *next_instance, int read) | |
1745 | { | |
1746 | struct held_lock *prev; | |
7531e2f3 | 1747 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1748 | int i; |
1749 | ||
1750 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1751 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1752 | |
1753 | if (prev->instance == next->nest_lock) | |
1754 | nest = prev; | |
1755 | ||
f82b217e | 1756 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1757 | continue; |
7531e2f3 | 1758 | |
fbb9ce95 IM |
1759 | /* |
1760 | * Allow read-after-read recursion of the same | |
6c9076ec | 1761 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1762 | */ |
6c9076ec | 1763 | if ((read == 2) && prev->read) |
fbb9ce95 | 1764 | return 2; |
7531e2f3 PZ |
1765 | |
1766 | /* | |
1767 | * We're holding the nest_lock, which serializes this lock's | |
1768 | * nesting behaviour. | |
1769 | */ | |
1770 | if (nest) | |
1771 | return 2; | |
1772 | ||
fbb9ce95 IM |
1773 | return print_deadlock_bug(curr, prev, next); |
1774 | } | |
1775 | return 1; | |
1776 | } | |
1777 | ||
1778 | /* | |
1779 | * There was a chain-cache miss, and we are about to add a new dependency | |
1780 | * to a previous lock. We recursively validate the following rules: | |
1781 | * | |
1782 | * - would the adding of the <prev> -> <next> dependency create a | |
1783 | * circular dependency in the graph? [== circular deadlock] | |
1784 | * | |
1785 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1786 | * (in the full backwards-subgraph starting at <prev>) with any | |
1787 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1788 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1789 | * | |
1790 | * - does the new prev->next dependency connect any softirq-safe lock | |
1791 | * (in the full backwards-subgraph starting at <prev>) with any | |
1792 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1793 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1794 | * | |
1795 | * any of these scenarios could lead to a deadlock. | |
1796 | * | |
1797 | * Then if all the validations pass, we add the forwards and backwards | |
1798 | * dependency. | |
1799 | */ | |
1800 | static int | |
1801 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
8a5fd564 | 1802 | struct held_lock *next, int distance, int *stack_saved) |
fbb9ce95 IM |
1803 | { |
1804 | struct lock_list *entry; | |
1805 | int ret; | |
db0002a3 ML |
1806 | struct lock_list this; |
1807 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1808 | /* |
1809 | * Static variable, serialized by the graph_lock(). | |
1810 | * | |
1811 | * We use this static variable to save the stack trace in case | |
1812 | * we call into this function multiple times due to encountering | |
1813 | * trylocks in the held lock stack. | |
1814 | */ | |
1815 | static struct stack_trace trace; | |
fbb9ce95 IM |
1816 | |
1817 | /* | |
1818 | * Prove that the new <prev> -> <next> dependency would not | |
1819 | * create a circular dependency in the graph. (We do this by | |
1820 | * forward-recursing into the graph starting at <next>, and | |
1821 | * checking whether we can reach <prev>.) | |
1822 | * | |
1823 | * We are using global variables to control the recursion, to | |
1824 | * keep the stackframe size of the recursive functions low: | |
1825 | */ | |
db0002a3 ML |
1826 | this.class = hlock_class(next); |
1827 | this.parent = NULL; | |
1828 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1829 | if (unlikely(!ret)) | |
1830 | return print_circular_bug(&this, target_entry, next, prev); | |
1831 | else if (unlikely(ret < 0)) | |
1832 | return print_bfs_bug(ret); | |
c94aa5ca | 1833 | |
8e18257d | 1834 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1835 | return 0; |
1836 | ||
fbb9ce95 IM |
1837 | /* |
1838 | * For recursive read-locks we do all the dependency checks, | |
1839 | * but we dont store read-triggered dependencies (only | |
1840 | * write-triggered dependencies). This ensures that only the | |
1841 | * write-side dependencies matter, and that if for example a | |
1842 | * write-lock never takes any other locks, then the reads are | |
1843 | * equivalent to a NOP. | |
1844 | */ | |
1845 | if (next->read == 2 || prev->read == 2) | |
1846 | return 1; | |
1847 | /* | |
1848 | * Is the <prev> -> <next> dependency already present? | |
1849 | * | |
1850 | * (this may occur even though this is a new chain: consider | |
1851 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1852 | * chains - the second one will be new, but L1 already has | |
1853 | * L2 added to its dependency list, due to the first chain.) | |
1854 | */ | |
f82b217e DJ |
1855 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1856 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1857 | if (distance == 1) |
1858 | entry->distance = 1; | |
fbb9ce95 | 1859 | return 2; |
068135e6 | 1860 | } |
fbb9ce95 IM |
1861 | } |
1862 | ||
8a5fd564 DV |
1863 | if (!*stack_saved) { |
1864 | if (!save_trace(&trace)) | |
1865 | return 0; | |
1866 | *stack_saved = 1; | |
1867 | } | |
4726f2a6 | 1868 | |
fbb9ce95 IM |
1869 | /* |
1870 | * Ok, all validations passed, add the new lock | |
1871 | * to the previous lock's dependency list: | |
1872 | */ | |
83f06168 | 1873 | ret = add_lock_to_list(hlock_class(next), |
f82b217e | 1874 | &hlock_class(prev)->locks_after, |
4726f2a6 | 1875 | next->acquire_ip, distance, &trace); |
068135e6 | 1876 | |
fbb9ce95 IM |
1877 | if (!ret) |
1878 | return 0; | |
910b1b2e | 1879 | |
83f06168 | 1880 | ret = add_lock_to_list(hlock_class(prev), |
f82b217e | 1881 | &hlock_class(next)->locks_before, |
4726f2a6 | 1882 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1883 | if (!ret) |
1884 | return 0; | |
fbb9ce95 IM |
1885 | |
1886 | /* | |
8e18257d PZ |
1887 | * Debugging printouts: |
1888 | */ | |
f82b217e | 1889 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8a5fd564 DV |
1890 | /* We drop graph lock, so another thread can overwrite trace. */ |
1891 | *stack_saved = 0; | |
8e18257d PZ |
1892 | graph_unlock(); |
1893 | printk("\n new dependency: "); | |
f82b217e | 1894 | print_lock_name(hlock_class(prev)); |
f943fe0f | 1895 | printk(KERN_CONT " => "); |
f82b217e | 1896 | print_lock_name(hlock_class(next)); |
f943fe0f | 1897 | printk(KERN_CONT "\n"); |
fbb9ce95 | 1898 | dump_stack(); |
8e18257d | 1899 | return graph_lock(); |
fbb9ce95 | 1900 | } |
8e18257d PZ |
1901 | return 1; |
1902 | } | |
fbb9ce95 | 1903 | |
8e18257d PZ |
1904 | /* |
1905 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1906 | * The ones that are relevant are (in increasing distance from curr): | |
1907 | * all consecutive trylock entries and the final non-trylock entry - or | |
1908 | * the end of this context's lock-chain - whichever comes first. | |
1909 | */ | |
1910 | static int | |
1911 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1912 | { | |
1913 | int depth = curr->lockdep_depth; | |
8a5fd564 | 1914 | int stack_saved = 0; |
8e18257d | 1915 | struct held_lock *hlock; |
d6d897ce | 1916 | |
fbb9ce95 | 1917 | /* |
8e18257d PZ |
1918 | * Debugging checks. |
1919 | * | |
1920 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1921 | */ |
8e18257d PZ |
1922 | if (!depth) |
1923 | goto out_bug; | |
fbb9ce95 | 1924 | /* |
8e18257d PZ |
1925 | * At least two relevant locks must exist for this |
1926 | * to be a head: | |
fbb9ce95 | 1927 | */ |
8e18257d PZ |
1928 | if (curr->held_locks[depth].irq_context != |
1929 | curr->held_locks[depth-1].irq_context) | |
1930 | goto out_bug; | |
74c383f1 | 1931 | |
8e18257d PZ |
1932 | for (;;) { |
1933 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 1934 | hlock = curr->held_locks + depth - 1; |
8e18257d PZ |
1935 | /* |
1936 | * Only non-recursive-read entries get new dependencies | |
1937 | * added: | |
1938 | */ | |
1b5ff816 | 1939 | if (hlock->read != 2 && hlock->check) { |
4726f2a6 | 1940 | if (!check_prev_add(curr, hlock, next, |
8a5fd564 | 1941 | distance, &stack_saved)) |
8e18257d PZ |
1942 | return 0; |
1943 | /* | |
1944 | * Stop after the first non-trylock entry, | |
1945 | * as non-trylock entries have added their | |
1946 | * own direct dependencies already, so this | |
1947 | * lock is connected to them indirectly: | |
1948 | */ | |
1949 | if (!hlock->trylock) | |
1950 | break; | |
74c383f1 | 1951 | } |
8e18257d PZ |
1952 | depth--; |
1953 | /* | |
1954 | * End of lock-stack? | |
1955 | */ | |
1956 | if (!depth) | |
1957 | break; | |
1958 | /* | |
1959 | * Stop the search if we cross into another context: | |
1960 | */ | |
1961 | if (curr->held_locks[depth].irq_context != | |
1962 | curr->held_locks[depth-1].irq_context) | |
1963 | break; | |
fbb9ce95 | 1964 | } |
8e18257d PZ |
1965 | return 1; |
1966 | out_bug: | |
1967 | if (!debug_locks_off_graph_unlock()) | |
1968 | return 0; | |
fbb9ce95 | 1969 | |
0119fee4 PZ |
1970 | /* |
1971 | * Clearly we all shouldn't be here, but since we made it we | |
1972 | * can reliable say we messed up our state. See the above two | |
1973 | * gotos for reasons why we could possibly end up here. | |
1974 | */ | |
8e18257d | 1975 | WARN_ON(1); |
fbb9ce95 | 1976 | |
8e18257d | 1977 | return 0; |
fbb9ce95 IM |
1978 | } |
1979 | ||
8e18257d | 1980 | unsigned long nr_lock_chains; |
443cd507 | 1981 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1982 | int nr_chain_hlocks; |
443cd507 HY |
1983 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1984 | ||
1985 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1986 | { | |
1987 | return lock_classes + chain_hlocks[chain->base + i]; | |
1988 | } | |
8e18257d | 1989 | |
9e4e7554 IM |
1990 | /* |
1991 | * Returns the index of the first held_lock of the current chain | |
1992 | */ | |
1993 | static inline int get_first_held_lock(struct task_struct *curr, | |
1994 | struct held_lock *hlock) | |
1995 | { | |
1996 | int i; | |
1997 | struct held_lock *hlock_curr; | |
1998 | ||
1999 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2000 | hlock_curr = curr->held_locks + i; | |
2001 | if (hlock_curr->irq_context != hlock->irq_context) | |
2002 | break; | |
2003 | ||
2004 | } | |
2005 | ||
2006 | return ++i; | |
2007 | } | |
2008 | ||
5c8a010c | 2009 | #ifdef CONFIG_DEBUG_LOCKDEP |
39e2e173 AAF |
2010 | /* |
2011 | * Returns the next chain_key iteration | |
2012 | */ | |
2013 | static u64 print_chain_key_iteration(int class_idx, u64 chain_key) | |
2014 | { | |
2015 | u64 new_chain_key = iterate_chain_key(chain_key, class_idx); | |
2016 | ||
2017 | printk(" class_idx:%d -> chain_key:%016Lx", | |
2018 | class_idx, | |
2019 | (unsigned long long)new_chain_key); | |
2020 | return new_chain_key; | |
2021 | } | |
2022 | ||
2023 | static void | |
2024 | print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) | |
2025 | { | |
2026 | struct held_lock *hlock; | |
2027 | u64 chain_key = 0; | |
2028 | int depth = curr->lockdep_depth; | |
2029 | int i; | |
2030 | ||
2031 | printk("depth: %u\n", depth + 1); | |
2032 | for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { | |
2033 | hlock = curr->held_locks + i; | |
2034 | chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); | |
2035 | ||
2036 | print_lock(hlock); | |
2037 | } | |
2038 | ||
2039 | print_chain_key_iteration(hlock_next->class_idx, chain_key); | |
2040 | print_lock(hlock_next); | |
2041 | } | |
2042 | ||
2043 | static void print_chain_keys_chain(struct lock_chain *chain) | |
2044 | { | |
2045 | int i; | |
2046 | u64 chain_key = 0; | |
2047 | int class_id; | |
2048 | ||
2049 | printk("depth: %u\n", chain->depth); | |
2050 | for (i = 0; i < chain->depth; i++) { | |
2051 | class_id = chain_hlocks[chain->base + i]; | |
2052 | chain_key = print_chain_key_iteration(class_id + 1, chain_key); | |
2053 | ||
2054 | print_lock_name(lock_classes + class_id); | |
2055 | printk("\n"); | |
2056 | } | |
2057 | } | |
2058 | ||
2059 | static void print_collision(struct task_struct *curr, | |
2060 | struct held_lock *hlock_next, | |
2061 | struct lock_chain *chain) | |
2062 | { | |
2063 | printk("\n"); | |
2064 | printk("======================\n"); | |
2065 | printk("[chain_key collision ]\n"); | |
2066 | print_kernel_ident(); | |
2067 | printk("----------------------\n"); | |
2068 | printk("%s/%d: ", current->comm, task_pid_nr(current)); | |
2069 | printk("Hash chain already cached but the contents don't match!\n"); | |
2070 | ||
2071 | printk("Held locks:"); | |
2072 | print_chain_keys_held_locks(curr, hlock_next); | |
2073 | ||
2074 | printk("Locks in cached chain:"); | |
2075 | print_chain_keys_chain(chain); | |
2076 | ||
2077 | printk("\nstack backtrace:\n"); | |
2078 | dump_stack(); | |
2079 | } | |
5c8a010c | 2080 | #endif |
39e2e173 | 2081 | |
9e4e7554 IM |
2082 | /* |
2083 | * Checks whether the chain and the current held locks are consistent | |
2084 | * in depth and also in content. If they are not it most likely means | |
2085 | * that there was a collision during the calculation of the chain_key. | |
2086 | * Returns: 0 not passed, 1 passed | |
2087 | */ | |
2088 | static int check_no_collision(struct task_struct *curr, | |
2089 | struct held_lock *hlock, | |
2090 | struct lock_chain *chain) | |
2091 | { | |
2092 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2093 | int i, j, id; | |
2094 | ||
2095 | i = get_first_held_lock(curr, hlock); | |
2096 | ||
39e2e173 AAF |
2097 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { |
2098 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2099 | return 0; |
39e2e173 | 2100 | } |
9e4e7554 IM |
2101 | |
2102 | for (j = 0; j < chain->depth - 1; j++, i++) { | |
2103 | id = curr->held_locks[i].class_idx - 1; | |
2104 | ||
39e2e173 AAF |
2105 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { |
2106 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2107 | return 0; |
39e2e173 | 2108 | } |
9e4e7554 IM |
2109 | } |
2110 | #endif | |
2111 | return 1; | |
2112 | } | |
2113 | ||
fbb9ce95 IM |
2114 | /* |
2115 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
2116 | * add it and return 1 - in this case the new dependency chain is |
2117 | * validated. If the key is already hashed, return 0. | |
2118 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 2119 | */ |
443cd507 HY |
2120 | static inline int lookup_chain_cache(struct task_struct *curr, |
2121 | struct held_lock *hlock, | |
2122 | u64 chain_key) | |
fbb9ce95 | 2123 | { |
f82b217e | 2124 | struct lock_class *class = hlock_class(hlock); |
a63f38cc | 2125 | struct hlist_head *hash_head = chainhashentry(chain_key); |
fbb9ce95 | 2126 | struct lock_chain *chain; |
e0944ee6 | 2127 | int i, j; |
fbb9ce95 | 2128 | |
0119fee4 PZ |
2129 | /* |
2130 | * We might need to take the graph lock, ensure we've got IRQs | |
2131 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2132 | * lockdep won't complain about its own locking errors. | |
2133 | */ | |
381a2292 JP |
2134 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2135 | return 0; | |
fbb9ce95 IM |
2136 | /* |
2137 | * We can walk it lock-free, because entries only get added | |
2138 | * to the hash: | |
2139 | */ | |
a63f38cc | 2140 | hlist_for_each_entry_rcu(chain, hash_head, entry) { |
fbb9ce95 IM |
2141 | if (chain->chain_key == chain_key) { |
2142 | cache_hit: | |
bd6d29c2 | 2143 | debug_atomic_inc(chain_lookup_hits); |
9e4e7554 IM |
2144 | if (!check_no_collision(curr, hlock, chain)) |
2145 | return 0; | |
2146 | ||
81fc685a | 2147 | if (very_verbose(class)) |
755cd900 AM |
2148 | printk("\nhash chain already cached, key: " |
2149 | "%016Lx tail class: [%p] %s\n", | |
2150 | (unsigned long long)chain_key, | |
2151 | class->key, class->name); | |
fbb9ce95 IM |
2152 | return 0; |
2153 | } | |
2154 | } | |
81fc685a | 2155 | if (very_verbose(class)) |
755cd900 AM |
2156 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2157 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2158 | /* |
2159 | * Allocate a new chain entry from the static array, and add | |
2160 | * it to the hash: | |
2161 | */ | |
74c383f1 IM |
2162 | if (!graph_lock()) |
2163 | return 0; | |
fbb9ce95 IM |
2164 | /* |
2165 | * We have to walk the chain again locked - to avoid duplicates: | |
2166 | */ | |
a63f38cc | 2167 | hlist_for_each_entry(chain, hash_head, entry) { |
fbb9ce95 | 2168 | if (chain->chain_key == chain_key) { |
74c383f1 | 2169 | graph_unlock(); |
fbb9ce95 IM |
2170 | goto cache_hit; |
2171 | } | |
2172 | } | |
2173 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2174 | if (!debug_locks_off_graph_unlock()) |
2175 | return 0; | |
2176 | ||
2c522836 | 2177 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2178 | dump_stack(); |
fbb9ce95 IM |
2179 | return 0; |
2180 | } | |
2181 | chain = lock_chains + nr_lock_chains++; | |
2182 | chain->chain_key = chain_key; | |
443cd507 | 2183 | chain->irq_context = hlock->irq_context; |
9e4e7554 | 2184 | i = get_first_held_lock(curr, hlock); |
443cd507 | 2185 | chain->depth = curr->lockdep_depth + 1 - i; |
75dd602a PZ |
2186 | |
2187 | BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks)); | |
2188 | BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks)); | |
2189 | BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes)); | |
2190 | ||
e0944ee6 SR |
2191 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2192 | chain->base = nr_chain_hlocks; | |
443cd507 | 2193 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2194 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2195 | chain_hlocks[chain->base + j] = lock_id; |
2196 | } | |
2197 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2198 | } | |
75dd602a PZ |
2199 | |
2200 | if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS) | |
2201 | nr_chain_hlocks += chain->depth; | |
2202 | ||
2203 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2204 | /* | |
2205 | * Important for check_no_collision(). | |
2206 | */ | |
2207 | if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
f9af456a | 2208 | if (!debug_locks_off_graph_unlock()) |
75dd602a PZ |
2209 | return 0; |
2210 | ||
2211 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); | |
2212 | dump_stack(); | |
2213 | return 0; | |
2214 | } | |
2215 | #endif | |
2216 | ||
a63f38cc | 2217 | hlist_add_head_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2218 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2219 | inc_chains(); |
2220 | ||
2221 | return 1; | |
2222 | } | |
2223 | ||
2224 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2225 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2226 | { |
2227 | /* | |
2228 | * Trylock needs to maintain the stack of held locks, but it | |
2229 | * does not add new dependencies, because trylock can be done | |
2230 | * in any order. | |
2231 | * | |
2232 | * We look up the chain_key and do the O(N^2) check and update of | |
2233 | * the dependencies only if this is a new dependency chain. | |
2234 | * (If lookup_chain_cache() returns with 1 it acquires | |
2235 | * graph_lock for us) | |
2236 | */ | |
fb9edbe9 | 2237 | if (!hlock->trylock && hlock->check && |
443cd507 | 2238 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2239 | /* |
2240 | * Check whether last held lock: | |
2241 | * | |
2242 | * - is irq-safe, if this lock is irq-unsafe | |
2243 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2244 | * | |
2245 | * And check whether the new lock's dependency graph | |
2246 | * could lead back to the previous lock. | |
2247 | * | |
2248 | * any of these scenarios could lead to a deadlock. If | |
2249 | * All validations | |
2250 | */ | |
2251 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2252 | ||
2253 | if (!ret) | |
2254 | return 0; | |
2255 | /* | |
2256 | * Mark recursive read, as we jump over it when | |
2257 | * building dependencies (just like we jump over | |
2258 | * trylock entries): | |
2259 | */ | |
2260 | if (ret == 2) | |
2261 | hlock->read = 2; | |
2262 | /* | |
2263 | * Add dependency only if this lock is not the head | |
2264 | * of the chain, and if it's not a secondary read-lock: | |
2265 | */ | |
2266 | if (!chain_head && ret != 2) | |
2267 | if (!check_prevs_add(curr, hlock)) | |
2268 | return 0; | |
2269 | graph_unlock(); | |
2270 | } else | |
2271 | /* after lookup_chain_cache(): */ | |
2272 | if (unlikely(!debug_locks)) | |
2273 | return 0; | |
fbb9ce95 IM |
2274 | |
2275 | return 1; | |
2276 | } | |
8e18257d PZ |
2277 | #else |
2278 | static inline int validate_chain(struct task_struct *curr, | |
2279 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2280 | int chain_head, u64 chain_key) |
8e18257d PZ |
2281 | { |
2282 | return 1; | |
2283 | } | |
ca58abcb | 2284 | #endif |
fbb9ce95 IM |
2285 | |
2286 | /* | |
2287 | * We are building curr_chain_key incrementally, so double-check | |
2288 | * it from scratch, to make sure that it's done correctly: | |
2289 | */ | |
1d09daa5 | 2290 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2291 | { |
2292 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2293 | struct held_lock *hlock, *prev_hlock = NULL; | |
5f18ab5c | 2294 | unsigned int i; |
fbb9ce95 IM |
2295 | u64 chain_key = 0; |
2296 | ||
2297 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2298 | hlock = curr->held_locks + i; | |
2299 | if (chain_key != hlock->prev_chain_key) { | |
2300 | debug_locks_off(); | |
0119fee4 PZ |
2301 | /* |
2302 | * We got mighty confused, our chain keys don't match | |
2303 | * with what we expect, someone trample on our task state? | |
2304 | */ | |
2df8b1d6 | 2305 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2306 | curr->lockdep_depth, i, |
2307 | (unsigned long long)chain_key, | |
2308 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2309 | return; |
2310 | } | |
0119fee4 PZ |
2311 | /* |
2312 | * Whoops ran out of static storage again? | |
2313 | */ | |
5f18ab5c | 2314 | if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) |
381a2292 JP |
2315 | return; |
2316 | ||
fbb9ce95 IM |
2317 | if (prev_hlock && (prev_hlock->irq_context != |
2318 | hlock->irq_context)) | |
2319 | chain_key = 0; | |
5f18ab5c | 2320 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
fbb9ce95 IM |
2321 | prev_hlock = hlock; |
2322 | } | |
2323 | if (chain_key != curr->curr_chain_key) { | |
2324 | debug_locks_off(); | |
0119fee4 PZ |
2325 | /* |
2326 | * More smoking hash instead of calculating it, damn see these | |
2327 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2328 | */ | |
2df8b1d6 | 2329 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2330 | curr->lockdep_depth, i, |
2331 | (unsigned long long)chain_key, | |
2332 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2333 | } |
2334 | #endif | |
2335 | } | |
2336 | ||
282b5c2f SR |
2337 | static void |
2338 | print_usage_bug_scenario(struct held_lock *lock) | |
2339 | { | |
2340 | struct lock_class *class = hlock_class(lock); | |
2341 | ||
2342 | printk(" Possible unsafe locking scenario:\n\n"); | |
2343 | printk(" CPU0\n"); | |
2344 | printk(" ----\n"); | |
2345 | printk(" lock("); | |
2346 | __print_lock_name(class); | |
f943fe0f | 2347 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2348 | printk(" <Interrupt>\n"); |
2349 | printk(" lock("); | |
2350 | __print_lock_name(class); | |
f943fe0f | 2351 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2352 | printk("\n *** DEADLOCK ***\n\n"); |
2353 | } | |
2354 | ||
8e18257d PZ |
2355 | static int |
2356 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2357 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2358 | { | |
2359 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2360 | return 0; | |
2361 | ||
b3fbab05 PM |
2362 | printk("\n"); |
2363 | printk("=================================\n"); | |
2364 | printk("[ INFO: inconsistent lock state ]\n"); | |
fbdc4b9a | 2365 | print_kernel_ident(); |
b3fbab05 | 2366 | printk("---------------------------------\n"); |
8e18257d PZ |
2367 | |
2368 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2369 | usage_str[prev_bit], usage_str[new_bit]); | |
2370 | ||
2371 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2372 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2373 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2374 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2375 | trace_hardirqs_enabled(curr), | |
2376 | trace_softirqs_enabled(curr)); | |
2377 | print_lock(this); | |
2378 | ||
2379 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2380 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2381 | |
2382 | print_irqtrace_events(curr); | |
2383 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2384 | print_usage_bug_scenario(this); |
2385 | ||
8e18257d PZ |
2386 | lockdep_print_held_locks(curr); |
2387 | ||
2388 | printk("\nstack backtrace:\n"); | |
2389 | dump_stack(); | |
2390 | ||
2391 | return 0; | |
2392 | } | |
2393 | ||
2394 | /* | |
2395 | * Print out an error if an invalid bit is set: | |
2396 | */ | |
2397 | static inline int | |
2398 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2399 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2400 | { | |
f82b217e | 2401 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2402 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2403 | return 1; | |
2404 | } | |
2405 | ||
2406 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2407 | enum lock_usage_bit new_bit); | |
2408 | ||
81d68a96 | 2409 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2410 | |
2411 | /* | |
2412 | * print irq inversion bug: | |
2413 | */ | |
2414 | static int | |
24208ca7 ML |
2415 | print_irq_inversion_bug(struct task_struct *curr, |
2416 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2417 | struct held_lock *this, int forwards, |
2418 | const char *irqclass) | |
2419 | { | |
dad3d743 SR |
2420 | struct lock_list *entry = other; |
2421 | struct lock_list *middle = NULL; | |
2422 | int depth; | |
2423 | ||
74c383f1 | 2424 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2425 | return 0; |
2426 | ||
b3fbab05 PM |
2427 | printk("\n"); |
2428 | printk("=========================================================\n"); | |
2429 | printk("[ INFO: possible irq lock inversion dependency detected ]\n"); | |
fbdc4b9a | 2430 | print_kernel_ident(); |
b3fbab05 | 2431 | printk("---------------------------------------------------------\n"); |
fbb9ce95 | 2432 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2433 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2434 | print_lock(this); |
2435 | if (forwards) | |
26575e28 | 2436 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2437 | else |
26575e28 | 2438 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2439 | print_lock_name(other->class); |
fbb9ce95 IM |
2440 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2441 | ||
2442 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2443 | |
2444 | /* Find a middle lock (if one exists) */ | |
2445 | depth = get_lock_depth(other); | |
2446 | do { | |
2447 | if (depth == 0 && (entry != root)) { | |
2448 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2449 | break; | |
2450 | } | |
2451 | middle = entry; | |
2452 | entry = get_lock_parent(entry); | |
2453 | depth--; | |
2454 | } while (entry && entry != root && (depth >= 0)); | |
2455 | if (forwards) | |
2456 | print_irq_lock_scenario(root, other, | |
2457 | middle ? middle->class : root->class, other->class); | |
2458 | else | |
2459 | print_irq_lock_scenario(other, root, | |
2460 | middle ? middle->class : other->class, root->class); | |
2461 | ||
fbb9ce95 IM |
2462 | lockdep_print_held_locks(curr); |
2463 | ||
24208ca7 ML |
2464 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2465 | if (!save_trace(&root->trace)) | |
2466 | return 0; | |
2467 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2468 | |
2469 | printk("\nstack backtrace:\n"); | |
2470 | dump_stack(); | |
2471 | ||
2472 | return 0; | |
2473 | } | |
2474 | ||
2475 | /* | |
2476 | * Prove that in the forwards-direction subgraph starting at <this> | |
2477 | * there is no lock matching <mask>: | |
2478 | */ | |
2479 | static int | |
2480 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2481 | enum lock_usage_bit bit, const char *irqclass) | |
2482 | { | |
2483 | int ret; | |
d7aaba14 ML |
2484 | struct lock_list root; |
2485 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2486 | |
d7aaba14 ML |
2487 | root.parent = NULL; |
2488 | root.class = hlock_class(this); | |
2489 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2490 | if (ret < 0) |
2491 | return print_bfs_bug(ret); | |
2492 | if (ret == 1) | |
2493 | return ret; | |
fbb9ce95 | 2494 | |
24208ca7 | 2495 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2496 | this, 1, irqclass); |
fbb9ce95 IM |
2497 | } |
2498 | ||
2499 | /* | |
2500 | * Prove that in the backwards-direction subgraph starting at <this> | |
2501 | * there is no lock matching <mask>: | |
2502 | */ | |
2503 | static int | |
2504 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2505 | enum lock_usage_bit bit, const char *irqclass) | |
2506 | { | |
2507 | int ret; | |
d7aaba14 ML |
2508 | struct lock_list root; |
2509 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2510 | |
d7aaba14 ML |
2511 | root.parent = NULL; |
2512 | root.class = hlock_class(this); | |
2513 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2514 | if (ret < 0) |
2515 | return print_bfs_bug(ret); | |
2516 | if (ret == 1) | |
2517 | return ret; | |
fbb9ce95 | 2518 | |
24208ca7 | 2519 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2520 | this, 0, irqclass); |
fbb9ce95 IM |
2521 | } |
2522 | ||
3117df04 | 2523 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2524 | { |
2525 | printk("irq event stamp: %u\n", curr->irq_events); | |
f943fe0f DV |
2526 | printk("hardirqs last enabled at (%u): [<%p>] %pS\n", |
2527 | curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip, | |
2528 | (void *)curr->hardirq_enable_ip); | |
2529 | printk("hardirqs last disabled at (%u): [<%p>] %pS\n", | |
2530 | curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip, | |
2531 | (void *)curr->hardirq_disable_ip); | |
2532 | printk("softirqs last enabled at (%u): [<%p>] %pS\n", | |
2533 | curr->softirq_enable_event, (void *)curr->softirq_enable_ip, | |
2534 | (void *)curr->softirq_enable_ip); | |
2535 | printk("softirqs last disabled at (%u): [<%p>] %pS\n", | |
2536 | curr->softirq_disable_event, (void *)curr->softirq_disable_ip, | |
2537 | (void *)curr->softirq_disable_ip); | |
fbb9ce95 IM |
2538 | } |
2539 | ||
cd95302d | 2540 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2541 | { |
8e18257d PZ |
2542 | #if HARDIRQ_VERBOSE |
2543 | return class_filter(class); | |
2544 | #endif | |
fbb9ce95 IM |
2545 | return 0; |
2546 | } | |
2547 | ||
cd95302d | 2548 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2549 | { |
8e18257d PZ |
2550 | #if SOFTIRQ_VERBOSE |
2551 | return class_filter(class); | |
2552 | #endif | |
2553 | return 0; | |
fbb9ce95 IM |
2554 | } |
2555 | ||
cd95302d | 2556 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2557 | { |
2558 | #if RECLAIM_VERBOSE | |
2559 | return class_filter(class); | |
2560 | #endif | |
2561 | return 0; | |
2562 | } | |
2563 | ||
fbb9ce95 IM |
2564 | #define STRICT_READ_CHECKS 1 |
2565 | ||
cd95302d PZ |
2566 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2567 | #define LOCKDEP_STATE(__STATE) \ | |
2568 | __STATE##_verbose, | |
2569 | #include "lockdep_states.h" | |
2570 | #undef LOCKDEP_STATE | |
2571 | }; | |
2572 | ||
2573 | static inline int state_verbose(enum lock_usage_bit bit, | |
2574 | struct lock_class *class) | |
2575 | { | |
2576 | return state_verbose_f[bit >> 2](class); | |
2577 | } | |
2578 | ||
42c50d54 PZ |
2579 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2580 | enum lock_usage_bit bit, const char *name); | |
2581 | ||
6a6904d3 | 2582 | static int |
1c21f14e PZ |
2583 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2584 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2585 | { |
f989209e | 2586 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2587 | int read = new_bit & 1; |
42c50d54 PZ |
2588 | int dir = new_bit & 2; |
2589 | ||
38aa2714 PZ |
2590 | /* |
2591 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2592 | * has ENABLED state, which would allow recursion deadlocks. | |
2593 | * | |
2594 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2595 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2596 | */ | |
42c50d54 PZ |
2597 | check_usage_f usage = dir ? |
2598 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2599 | |
38aa2714 PZ |
2600 | /* |
2601 | * Validate that this particular lock does not have conflicting | |
2602 | * usage states. | |
2603 | */ | |
6a6904d3 PZ |
2604 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2605 | return 0; | |
42c50d54 | 2606 | |
38aa2714 PZ |
2607 | /* |
2608 | * Validate that the lock dependencies don't have conflicting usage | |
2609 | * states. | |
2610 | */ | |
2611 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2612 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2613 | return 0; |
780e820b | 2614 | |
38aa2714 PZ |
2615 | /* |
2616 | * Check for read in write conflicts | |
2617 | */ | |
2618 | if (!read) { | |
2619 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2620 | return 0; | |
2621 | ||
2622 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2623 | !usage(curr, this, excl_bit + 1, |
2624 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2625 | return 0; |
2626 | } | |
780e820b | 2627 | |
cd95302d | 2628 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2629 | return 2; |
2630 | ||
2631 | return 1; | |
2632 | } | |
2633 | ||
cf40bd16 | 2634 | enum mark_type { |
36bfb9bb PZ |
2635 | #define LOCKDEP_STATE(__STATE) __STATE, |
2636 | #include "lockdep_states.h" | |
2637 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2638 | }; |
2639 | ||
fbb9ce95 IM |
2640 | /* |
2641 | * Mark all held locks with a usage bit: | |
2642 | */ | |
1d09daa5 | 2643 | static int |
cf40bd16 | 2644 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2645 | { |
2646 | enum lock_usage_bit usage_bit; | |
2647 | struct held_lock *hlock; | |
2648 | int i; | |
2649 | ||
2650 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2651 | hlock = curr->held_locks + i; | |
2652 | ||
cf2ad4d1 PZ |
2653 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2654 | if (hlock->read) | |
2655 | usage_bit += 1; /* READ */ | |
2656 | ||
2657 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2658 | |
34d0ed5e | 2659 | if (!hlock->check) |
efbe2eee PZ |
2660 | continue; |
2661 | ||
4ff773bb | 2662 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2663 | return 0; |
2664 | } | |
2665 | ||
2666 | return 1; | |
2667 | } | |
2668 | ||
fbb9ce95 IM |
2669 | /* |
2670 | * Hardirqs will be enabled: | |
2671 | */ | |
dd4e5d3a | 2672 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2673 | { |
2674 | struct task_struct *curr = current; | |
fbb9ce95 | 2675 | |
fbb9ce95 IM |
2676 | /* we'll do an OFF -> ON transition: */ |
2677 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2678 | |
fbb9ce95 IM |
2679 | /* |
2680 | * We are going to turn hardirqs on, so set the | |
2681 | * usage bit for all held locks: | |
2682 | */ | |
cf40bd16 | 2683 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2684 | return; |
2685 | /* | |
2686 | * If we have softirqs enabled, then set the usage | |
2687 | * bit for all held locks. (disabled hardirqs prevented | |
2688 | * this bit from being set before) | |
2689 | */ | |
2690 | if (curr->softirqs_enabled) | |
cf40bd16 | 2691 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2692 | return; |
2693 | ||
8e18257d PZ |
2694 | curr->hardirq_enable_ip = ip; |
2695 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2696 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2697 | } |
dd4e5d3a | 2698 | |
b35f8305 | 2699 | __visible void trace_hardirqs_on_caller(unsigned long ip) |
dd4e5d3a PZ |
2700 | { |
2701 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2702 | ||
2703 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2704 | return; | |
2705 | ||
7d36b26b PZ |
2706 | if (unlikely(current->hardirqs_enabled)) { |
2707 | /* | |
2708 | * Neither irq nor preemption are disabled here | |
2709 | * so this is racy by nature but losing one hit | |
2710 | * in a stat is not a big deal. | |
2711 | */ | |
2712 | __debug_atomic_inc(redundant_hardirqs_on); | |
2713 | return; | |
2714 | } | |
2715 | ||
0119fee4 PZ |
2716 | /* |
2717 | * We're enabling irqs and according to our state above irqs weren't | |
2718 | * already enabled, yet we find the hardware thinks they are in fact | |
2719 | * enabled.. someone messed up their IRQ state tracing. | |
2720 | */ | |
dd4e5d3a PZ |
2721 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2722 | return; | |
2723 | ||
0119fee4 PZ |
2724 | /* |
2725 | * See the fine text that goes along with this variable definition. | |
2726 | */ | |
7d36b26b PZ |
2727 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2728 | return; | |
2729 | ||
0119fee4 PZ |
2730 | /* |
2731 | * Can't allow enabling interrupts while in an interrupt handler, | |
2732 | * that's general bad form and such. Recursion, limited stack etc.. | |
2733 | */ | |
7d36b26b PZ |
2734 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2735 | return; | |
2736 | ||
dd4e5d3a PZ |
2737 | current->lockdep_recursion = 1; |
2738 | __trace_hardirqs_on_caller(ip); | |
2739 | current->lockdep_recursion = 0; | |
2740 | } | |
81d68a96 | 2741 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2742 | |
1d09daa5 | 2743 | void trace_hardirqs_on(void) |
81d68a96 SR |
2744 | { |
2745 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2746 | } | |
8e18257d PZ |
2747 | EXPORT_SYMBOL(trace_hardirqs_on); |
2748 | ||
2749 | /* | |
2750 | * Hardirqs were disabled: | |
2751 | */ | |
b35f8305 | 2752 | __visible void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2753 | { |
2754 | struct task_struct *curr = current; | |
2755 | ||
6afe40b4 | 2756 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2757 | |
8e18257d PZ |
2758 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2759 | return; | |
2760 | ||
0119fee4 PZ |
2761 | /* |
2762 | * So we're supposed to get called after you mask local IRQs, but for | |
2763 | * some reason the hardware doesn't quite think you did a proper job. | |
2764 | */ | |
8e18257d PZ |
2765 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2766 | return; | |
2767 | ||
2768 | if (curr->hardirqs_enabled) { | |
2769 | /* | |
2770 | * We have done an ON -> OFF transition: | |
2771 | */ | |
2772 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2773 | curr->hardirq_disable_ip = ip; |
8e18257d | 2774 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2775 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2776 | } else |
bd6d29c2 | 2777 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2778 | } |
81d68a96 | 2779 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2780 | |
1d09daa5 | 2781 | void trace_hardirqs_off(void) |
81d68a96 SR |
2782 | { |
2783 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2784 | } | |
8e18257d PZ |
2785 | EXPORT_SYMBOL(trace_hardirqs_off); |
2786 | ||
2787 | /* | |
2788 | * Softirqs will be enabled: | |
2789 | */ | |
2790 | void trace_softirqs_on(unsigned long ip) | |
2791 | { | |
2792 | struct task_struct *curr = current; | |
2793 | ||
dd4e5d3a | 2794 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2795 | return; |
2796 | ||
0119fee4 PZ |
2797 | /* |
2798 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2799 | * funny state and nesting things. | |
2800 | */ | |
8e18257d PZ |
2801 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2802 | return; | |
2803 | ||
2804 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2805 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2806 | return; |
2807 | } | |
2808 | ||
dd4e5d3a | 2809 | current->lockdep_recursion = 1; |
8e18257d PZ |
2810 | /* |
2811 | * We'll do an OFF -> ON transition: | |
2812 | */ | |
2813 | curr->softirqs_enabled = 1; | |
2814 | curr->softirq_enable_ip = ip; | |
2815 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2816 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2817 | /* |
2818 | * We are going to turn softirqs on, so set the | |
2819 | * usage bit for all held locks, if hardirqs are | |
2820 | * enabled too: | |
2821 | */ | |
2822 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2823 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2824 | current->lockdep_recursion = 0; |
8e18257d PZ |
2825 | } |
2826 | ||
2827 | /* | |
2828 | * Softirqs were disabled: | |
2829 | */ | |
2830 | void trace_softirqs_off(unsigned long ip) | |
2831 | { | |
2832 | struct task_struct *curr = current; | |
2833 | ||
dd4e5d3a | 2834 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2835 | return; |
2836 | ||
0119fee4 PZ |
2837 | /* |
2838 | * We fancy IRQs being disabled here, see softirq.c | |
2839 | */ | |
8e18257d PZ |
2840 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2841 | return; | |
2842 | ||
2843 | if (curr->softirqs_enabled) { | |
2844 | /* | |
2845 | * We have done an ON -> OFF transition: | |
2846 | */ | |
2847 | curr->softirqs_enabled = 0; | |
2848 | curr->softirq_disable_ip = ip; | |
2849 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2850 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
2851 | /* |
2852 | * Whoops, we wanted softirqs off, so why aren't they? | |
2853 | */ | |
8e18257d PZ |
2854 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2855 | } else | |
bd6d29c2 | 2856 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2857 | } |
2858 | ||
2f850181 | 2859 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2860 | { |
2861 | struct task_struct *curr = current; | |
2862 | ||
2863 | if (unlikely(!debug_locks)) | |
2864 | return; | |
2865 | ||
2866 | /* no reclaim without waiting on it */ | |
d0164adc | 2867 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) |
cf40bd16 NP |
2868 | return; |
2869 | ||
2870 | /* this guy won't enter reclaim */ | |
2871 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2872 | return; | |
2873 | ||
2874 | /* We're only interested __GFP_FS allocations for now */ | |
2875 | if (!(gfp_mask & __GFP_FS)) | |
2876 | return; | |
2877 | ||
0119fee4 PZ |
2878 | /* |
2879 | * Oi! Can't be having __GFP_FS allocations with IRQs disabled. | |
2880 | */ | |
2f850181 | 2881 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2882 | return; |
2883 | ||
2884 | mark_held_locks(curr, RECLAIM_FS); | |
2885 | } | |
2886 | ||
2f850181 PZ |
2887 | static void check_flags(unsigned long flags); |
2888 | ||
2889 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2890 | { | |
2891 | unsigned long flags; | |
2892 | ||
2893 | if (unlikely(current->lockdep_recursion)) | |
2894 | return; | |
2895 | ||
2896 | raw_local_irq_save(flags); | |
2897 | check_flags(flags); | |
2898 | current->lockdep_recursion = 1; | |
2899 | __lockdep_trace_alloc(gfp_mask, flags); | |
2900 | current->lockdep_recursion = 0; | |
2901 | raw_local_irq_restore(flags); | |
2902 | } | |
2903 | ||
8e18257d PZ |
2904 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2905 | { | |
2906 | /* | |
2907 | * If non-trylock use in a hardirq or softirq context, then | |
2908 | * mark the lock as used in these contexts: | |
2909 | */ | |
2910 | if (!hlock->trylock) { | |
2911 | if (hlock->read) { | |
2912 | if (curr->hardirq_context) | |
2913 | if (!mark_lock(curr, hlock, | |
2914 | LOCK_USED_IN_HARDIRQ_READ)) | |
2915 | return 0; | |
2916 | if (curr->softirq_context) | |
2917 | if (!mark_lock(curr, hlock, | |
2918 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2919 | return 0; | |
2920 | } else { | |
2921 | if (curr->hardirq_context) | |
2922 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2923 | return 0; | |
2924 | if (curr->softirq_context) | |
2925 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2926 | return 0; | |
2927 | } | |
2928 | } | |
2929 | if (!hlock->hardirqs_off) { | |
2930 | if (hlock->read) { | |
2931 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2932 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2933 | return 0; |
2934 | if (curr->softirqs_enabled) | |
2935 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2936 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2937 | return 0; |
2938 | } else { | |
2939 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2940 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2941 | return 0; |
2942 | if (curr->softirqs_enabled) | |
2943 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2944 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2945 | return 0; |
2946 | } | |
2947 | } | |
2948 | ||
cf40bd16 NP |
2949 | /* |
2950 | * We reuse the irq context infrastructure more broadly as a general | |
2951 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2952 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2953 | * allocation). | |
2954 | */ | |
2955 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2956 | if (hlock->read) { | |
2957 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2958 | return 0; | |
2959 | } else { | |
2960 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2961 | return 0; | |
2962 | } | |
2963 | } | |
2964 | ||
8e18257d PZ |
2965 | return 1; |
2966 | } | |
2967 | ||
c2469756 BF |
2968 | static inline unsigned int task_irq_context(struct task_struct *task) |
2969 | { | |
2970 | return 2 * !!task->hardirq_context + !!task->softirq_context; | |
2971 | } | |
2972 | ||
8e18257d PZ |
2973 | static int separate_irq_context(struct task_struct *curr, |
2974 | struct held_lock *hlock) | |
2975 | { | |
2976 | unsigned int depth = curr->lockdep_depth; | |
2977 | ||
2978 | /* | |
2979 | * Keep track of points where we cross into an interrupt context: | |
2980 | */ | |
8e18257d PZ |
2981 | if (depth) { |
2982 | struct held_lock *prev_hlock; | |
2983 | ||
2984 | prev_hlock = curr->held_locks + depth-1; | |
2985 | /* | |
2986 | * If we cross into another context, reset the | |
2987 | * hash key (this also prevents the checking and the | |
2988 | * adding of the dependency to 'prev'): | |
2989 | */ | |
2990 | if (prev_hlock->irq_context != hlock->irq_context) | |
2991 | return 1; | |
2992 | } | |
2993 | return 0; | |
fbb9ce95 IM |
2994 | } |
2995 | ||
0119fee4 | 2996 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 2997 | |
8e18257d PZ |
2998 | static inline |
2999 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
3000 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 3001 | { |
0119fee4 | 3002 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
3003 | return 1; |
3004 | } | |
fbb9ce95 | 3005 | |
8e18257d PZ |
3006 | static inline int mark_irqflags(struct task_struct *curr, |
3007 | struct held_lock *hlock) | |
3008 | { | |
3009 | return 1; | |
3010 | } | |
fbb9ce95 | 3011 | |
c2469756 BF |
3012 | static inline unsigned int task_irq_context(struct task_struct *task) |
3013 | { | |
3014 | return 0; | |
3015 | } | |
3016 | ||
8e18257d PZ |
3017 | static inline int separate_irq_context(struct task_struct *curr, |
3018 | struct held_lock *hlock) | |
3019 | { | |
3020 | return 0; | |
fbb9ce95 IM |
3021 | } |
3022 | ||
868a23a8 PZ |
3023 | void lockdep_trace_alloc(gfp_t gfp_mask) |
3024 | { | |
3025 | } | |
3026 | ||
0119fee4 | 3027 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
3028 | |
3029 | /* | |
8e18257d | 3030 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 3031 | */ |
1d09daa5 | 3032 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 3033 | enum lock_usage_bit new_bit) |
fbb9ce95 | 3034 | { |
8e18257d | 3035 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
3036 | |
3037 | /* | |
8e18257d PZ |
3038 | * If already set then do not dirty the cacheline, |
3039 | * nor do any checks: | |
fbb9ce95 | 3040 | */ |
f82b217e | 3041 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
3042 | return 1; |
3043 | ||
3044 | if (!graph_lock()) | |
3045 | return 0; | |
fbb9ce95 | 3046 | /* |
25985edc | 3047 | * Make sure we didn't race: |
fbb9ce95 | 3048 | */ |
f82b217e | 3049 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
3050 | graph_unlock(); |
3051 | return 1; | |
3052 | } | |
fbb9ce95 | 3053 | |
f82b217e | 3054 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 3055 | |
f82b217e | 3056 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 3057 | return 0; |
fbb9ce95 | 3058 | |
8e18257d | 3059 | switch (new_bit) { |
5346417e PZ |
3060 | #define LOCKDEP_STATE(__STATE) \ |
3061 | case LOCK_USED_IN_##__STATE: \ | |
3062 | case LOCK_USED_IN_##__STATE##_READ: \ | |
3063 | case LOCK_ENABLED_##__STATE: \ | |
3064 | case LOCK_ENABLED_##__STATE##_READ: | |
3065 | #include "lockdep_states.h" | |
3066 | #undef LOCKDEP_STATE | |
8e18257d PZ |
3067 | ret = mark_lock_irq(curr, this, new_bit); |
3068 | if (!ret) | |
3069 | return 0; | |
3070 | break; | |
3071 | case LOCK_USED: | |
bd6d29c2 | 3072 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
3073 | break; |
3074 | default: | |
3075 | if (!debug_locks_off_graph_unlock()) | |
3076 | return 0; | |
3077 | WARN_ON(1); | |
3078 | return 0; | |
3079 | } | |
fbb9ce95 | 3080 | |
8e18257d PZ |
3081 | graph_unlock(); |
3082 | ||
3083 | /* | |
3084 | * We must printk outside of the graph_lock: | |
3085 | */ | |
3086 | if (ret == 2) { | |
3087 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
3088 | print_lock(this); | |
3089 | print_irqtrace_events(curr); | |
3090 | dump_stack(); | |
3091 | } | |
3092 | ||
3093 | return ret; | |
3094 | } | |
fbb9ce95 IM |
3095 | |
3096 | /* | |
3097 | * Initialize a lock instance's lock-class mapping info: | |
3098 | */ | |
3099 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 3100 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 3101 | { |
d3d03d4f YZ |
3102 | int i; |
3103 | ||
3104 | kmemcheck_mark_initialized(lock, sizeof(*lock)); | |
3105 | ||
3106 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) | |
3107 | lock->class_cache[i] = NULL; | |
62016250 | 3108 | |
c8a25005 PZ |
3109 | #ifdef CONFIG_LOCK_STAT |
3110 | lock->cpu = raw_smp_processor_id(); | |
3111 | #endif | |
3112 | ||
0119fee4 PZ |
3113 | /* |
3114 | * Can't be having no nameless bastards around this place! | |
3115 | */ | |
c8a25005 PZ |
3116 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
3117 | lock->name = "NULL"; | |
fbb9ce95 | 3118 | return; |
c8a25005 PZ |
3119 | } |
3120 | ||
3121 | lock->name = name; | |
fbb9ce95 | 3122 | |
0119fee4 PZ |
3123 | /* |
3124 | * No key, no joy, we need to hash something. | |
3125 | */ | |
fbb9ce95 IM |
3126 | if (DEBUG_LOCKS_WARN_ON(!key)) |
3127 | return; | |
fbb9ce95 IM |
3128 | /* |
3129 | * Sanity check, the lock-class key must be persistent: | |
3130 | */ | |
3131 | if (!static_obj(key)) { | |
3132 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
3133 | /* |
3134 | * What it says above ^^^^^, I suggest you read it. | |
3135 | */ | |
fbb9ce95 IM |
3136 | DEBUG_LOCKS_WARN_ON(1); |
3137 | return; | |
3138 | } | |
fbb9ce95 | 3139 | lock->key = key; |
c8a25005 PZ |
3140 | |
3141 | if (unlikely(!debug_locks)) | |
3142 | return; | |
3143 | ||
35a9393c PZ |
3144 | if (subclass) { |
3145 | unsigned long flags; | |
3146 | ||
3147 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3148 | return; | |
3149 | ||
3150 | raw_local_irq_save(flags); | |
3151 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3152 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3153 | current->lockdep_recursion = 0; |
3154 | raw_local_irq_restore(flags); | |
3155 | } | |
fbb9ce95 | 3156 | } |
fbb9ce95 IM |
3157 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3158 | ||
1704f47b | 3159 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3160 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3161 | |
d0945950 ML |
3162 | static int |
3163 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3164 | struct held_lock *hlock, | |
3165 | unsigned long ip) | |
3166 | { | |
3167 | if (!debug_locks_off()) | |
3168 | return 0; | |
3169 | if (debug_locks_silent) | |
3170 | return 0; | |
3171 | ||
3172 | printk("\n"); | |
3173 | printk("==================================\n"); | |
3174 | printk("[ BUG: Nested lock was not taken ]\n"); | |
3175 | print_kernel_ident(); | |
3176 | printk("----------------------------------\n"); | |
3177 | ||
3178 | printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); | |
3179 | print_lock(hlock); | |
3180 | ||
3181 | printk("\nbut this task is not holding:\n"); | |
3182 | printk("%s\n", hlock->nest_lock->name); | |
3183 | ||
3184 | printk("\nstack backtrace:\n"); | |
3185 | dump_stack(); | |
3186 | ||
3187 | printk("\nother info that might help us debug this:\n"); | |
3188 | lockdep_print_held_locks(curr); | |
3189 | ||
3190 | printk("\nstack backtrace:\n"); | |
3191 | dump_stack(); | |
3192 | ||
3193 | return 0; | |
3194 | } | |
3195 | ||
f8319483 | 3196 | static int __lock_is_held(struct lockdep_map *lock, int read); |
d0945950 | 3197 | |
fbb9ce95 IM |
3198 | /* |
3199 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3200 | * We maintain the dependency maps and validate the locking attempt: | |
3201 | */ | |
3202 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3203 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3204 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3205 | int references, int pin_count) |
fbb9ce95 IM |
3206 | { |
3207 | struct task_struct *curr = current; | |
d6d897ce | 3208 | struct lock_class *class = NULL; |
fbb9ce95 | 3209 | struct held_lock *hlock; |
5f18ab5c | 3210 | unsigned int depth; |
fbb9ce95 | 3211 | int chain_head = 0; |
bb97a91e | 3212 | int class_idx; |
fbb9ce95 IM |
3213 | u64 chain_key; |
3214 | ||
3215 | if (unlikely(!debug_locks)) | |
3216 | return 0; | |
3217 | ||
0119fee4 PZ |
3218 | /* |
3219 | * Lockdep should run with IRQs disabled, otherwise we could | |
3220 | * get an interrupt which would want to take locks, which would | |
3221 | * end up in lockdep and have you got a head-ache already? | |
3222 | */ | |
fbb9ce95 IM |
3223 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3224 | return 0; | |
3225 | ||
fb9edbe9 ON |
3226 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3227 | check = 0; | |
1704f47b | 3228 | |
62016250 HM |
3229 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3230 | class = lock->class_cache[subclass]; | |
d6d897ce | 3231 | /* |
62016250 | 3232 | * Not cached? |
d6d897ce | 3233 | */ |
fbb9ce95 | 3234 | if (unlikely(!class)) { |
4dfbb9d8 | 3235 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3236 | if (!class) |
3237 | return 0; | |
3238 | } | |
bd6d29c2 | 3239 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3240 | if (very_verbose(class)) { |
3241 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3242 | if (class->name_version > 1) | |
f943fe0f DV |
3243 | printk(KERN_CONT "#%d", class->name_version); |
3244 | printk(KERN_CONT "\n"); | |
fbb9ce95 IM |
3245 | dump_stack(); |
3246 | } | |
3247 | ||
3248 | /* | |
3249 | * Add the lock to the list of currently held locks. | |
3250 | * (we dont increase the depth just yet, up until the | |
3251 | * dependency checks are done) | |
3252 | */ | |
3253 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3254 | /* |
3255 | * Ran out of static storage for our per-task lock stack again have we? | |
3256 | */ | |
fbb9ce95 IM |
3257 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3258 | return 0; | |
3259 | ||
bb97a91e PZ |
3260 | class_idx = class - lock_classes + 1; |
3261 | ||
3262 | if (depth) { | |
3263 | hlock = curr->held_locks + depth - 1; | |
3264 | if (hlock->class_idx == class_idx && nest_lock) { | |
7fb4a2ce PZ |
3265 | if (hlock->references) { |
3266 | /* | |
3267 | * Check: unsigned int references:12, overflow. | |
3268 | */ | |
3269 | if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) | |
3270 | return 0; | |
3271 | ||
bb97a91e | 3272 | hlock->references++; |
7fb4a2ce | 3273 | } else { |
bb97a91e | 3274 | hlock->references = 2; |
7fb4a2ce | 3275 | } |
bb97a91e PZ |
3276 | |
3277 | return 1; | |
3278 | } | |
3279 | } | |
3280 | ||
fbb9ce95 | 3281 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3282 | /* |
3283 | * Plain impossible, we just registered it and checked it weren't no | |
3284 | * NULL like.. I bet this mushroom I ate was good! | |
3285 | */ | |
f82b217e DJ |
3286 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3287 | return 0; | |
bb97a91e | 3288 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3289 | hlock->acquire_ip = ip; |
3290 | hlock->instance = lock; | |
7531e2f3 | 3291 | hlock->nest_lock = nest_lock; |
c2469756 | 3292 | hlock->irq_context = task_irq_context(curr); |
fbb9ce95 IM |
3293 | hlock->trylock = trylock; |
3294 | hlock->read = read; | |
3295 | hlock->check = check; | |
6951b12a | 3296 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3297 | hlock->references = references; |
f20786ff PZ |
3298 | #ifdef CONFIG_LOCK_STAT |
3299 | hlock->waittime_stamp = 0; | |
3365e779 | 3300 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3301 | #endif |
21199f27 | 3302 | hlock->pin_count = pin_count; |
fbb9ce95 | 3303 | |
fb9edbe9 | 3304 | if (check && !mark_irqflags(curr, hlock)) |
8e18257d PZ |
3305 | return 0; |
3306 | ||
fbb9ce95 | 3307 | /* mark it as used: */ |
4ff773bb | 3308 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3309 | return 0; |
8e18257d | 3310 | |
fbb9ce95 | 3311 | /* |
17aacfb9 | 3312 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3313 | * lock keys along the dependency chain. We save the hash value |
3314 | * at every step so that we can get the current hash easily | |
3315 | * after unlock. The chain hash is then used to cache dependency | |
3316 | * results. | |
3317 | * | |
3318 | * The 'key ID' is what is the most compact key value to drive | |
3319 | * the hash, not class->key. | |
3320 | */ | |
0119fee4 PZ |
3321 | /* |
3322 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3323 | */ | |
5f18ab5c | 3324 | if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) |
fbb9ce95 IM |
3325 | return 0; |
3326 | ||
3327 | chain_key = curr->curr_chain_key; | |
3328 | if (!depth) { | |
0119fee4 PZ |
3329 | /* |
3330 | * How can we have a chain hash when we ain't got no keys?! | |
3331 | */ | |
fbb9ce95 IM |
3332 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3333 | return 0; | |
3334 | chain_head = 1; | |
3335 | } | |
3336 | ||
3337 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3338 | if (separate_irq_context(curr, hlock)) { |
3339 | chain_key = 0; | |
3340 | chain_head = 1; | |
fbb9ce95 | 3341 | } |
5f18ab5c | 3342 | chain_key = iterate_chain_key(chain_key, class_idx); |
fbb9ce95 | 3343 | |
f8319483 | 3344 | if (nest_lock && !__lock_is_held(nest_lock, -1)) |
d0945950 ML |
3345 | return print_lock_nested_lock_not_held(curr, hlock, ip); |
3346 | ||
3aa416b0 | 3347 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3348 | return 0; |
381a2292 | 3349 | |
3aa416b0 | 3350 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3351 | curr->lockdep_depth++; |
3352 | check_chain_key(curr); | |
60e114d1 JP |
3353 | #ifdef CONFIG_DEBUG_LOCKDEP |
3354 | if (unlikely(!debug_locks)) | |
3355 | return 0; | |
3356 | #endif | |
fbb9ce95 IM |
3357 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3358 | debug_locks_off(); | |
2c522836 DJ |
3359 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3360 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3361 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3362 | |
3363 | lockdep_print_held_locks(current); | |
3364 | debug_show_all_locks(); | |
eedeeabd | 3365 | dump_stack(); |
c0540606 | 3366 | |
fbb9ce95 IM |
3367 | return 0; |
3368 | } | |
381a2292 | 3369 | |
fbb9ce95 IM |
3370 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3371 | max_lockdep_depth = curr->lockdep_depth; | |
3372 | ||
3373 | return 1; | |
3374 | } | |
3375 | ||
3376 | static int | |
f86f7554 | 3377 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3378 | unsigned long ip) |
3379 | { | |
3380 | if (!debug_locks_off()) | |
3381 | return 0; | |
3382 | if (debug_locks_silent) | |
3383 | return 0; | |
3384 | ||
b3fbab05 PM |
3385 | printk("\n"); |
3386 | printk("=====================================\n"); | |
3387 | printk("[ BUG: bad unlock balance detected! ]\n"); | |
fbdc4b9a | 3388 | print_kernel_ident(); |
b3fbab05 | 3389 | printk("-------------------------------------\n"); |
fbb9ce95 | 3390 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3391 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 3392 | print_lockdep_cache(lock); |
f943fe0f | 3393 | printk(KERN_CONT ") at:\n"); |
fbb9ce95 IM |
3394 | print_ip_sym(ip); |
3395 | printk("but there are no more locks to release!\n"); | |
3396 | printk("\nother info that might help us debug this:\n"); | |
3397 | lockdep_print_held_locks(curr); | |
3398 | ||
3399 | printk("\nstack backtrace:\n"); | |
3400 | dump_stack(); | |
3401 | ||
3402 | return 0; | |
3403 | } | |
3404 | ||
bb97a91e PZ |
3405 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3406 | { | |
3407 | if (hlock->instance == lock) | |
3408 | return 1; | |
3409 | ||
3410 | if (hlock->references) { | |
62016250 | 3411 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3412 | |
3413 | if (!class) | |
3414 | class = look_up_lock_class(lock, 0); | |
3415 | ||
80e0401e PZ |
3416 | /* |
3417 | * If look_up_lock_class() failed to find a class, we're trying | |
3418 | * to test if we hold a lock that has never yet been acquired. | |
3419 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3420 | * holding it either, so report failure. | |
3421 | */ | |
3422 | if (!class) | |
bb97a91e PZ |
3423 | return 0; |
3424 | ||
0119fee4 PZ |
3425 | /* |
3426 | * References, but not a lock we're actually ref-counting? | |
3427 | * State got messed up, follow the sites that change ->references | |
3428 | * and try to make sense of it. | |
3429 | */ | |
bb97a91e PZ |
3430 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3431 | return 0; | |
3432 | ||
3433 | if (hlock->class_idx == class - lock_classes + 1) | |
3434 | return 1; | |
3435 | } | |
3436 | ||
3437 | return 0; | |
3438 | } | |
3439 | ||
64aa348e | 3440 | static int |
00ef9f73 PZ |
3441 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3442 | struct lock_class_key *key, unsigned int subclass, | |
3443 | unsigned long ip) | |
64aa348e PZ |
3444 | { |
3445 | struct task_struct *curr = current; | |
3446 | struct held_lock *hlock, *prev_hlock; | |
3447 | struct lock_class *class; | |
3448 | unsigned int depth; | |
3449 | int i; | |
3450 | ||
3451 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3452 | /* |
3453 | * This function is about (re)setting the class of a held lock, | |
3454 | * yet we're not actually holding any locks. Naughty user! | |
3455 | */ | |
64aa348e PZ |
3456 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3457 | return 0; | |
3458 | ||
3459 | prev_hlock = NULL; | |
3460 | for (i = depth-1; i >= 0; i--) { | |
3461 | hlock = curr->held_locks + i; | |
3462 | /* | |
3463 | * We must not cross into another context: | |
3464 | */ | |
3465 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3466 | break; | |
bb97a91e | 3467 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3468 | goto found_it; |
3469 | prev_hlock = hlock; | |
3470 | } | |
f86f7554 | 3471 | return print_unlock_imbalance_bug(curr, lock, ip); |
64aa348e PZ |
3472 | |
3473 | found_it: | |
00ef9f73 | 3474 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3475 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3476 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3477 | |
3478 | curr->lockdep_depth = i; | |
3479 | curr->curr_chain_key = hlock->prev_chain_key; | |
3480 | ||
3481 | for (; i < depth; i++) { | |
3482 | hlock = curr->held_locks + i; | |
3483 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3484 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3485 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3486 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3487 | hlock->references, hlock->pin_count)) |
64aa348e PZ |
3488 | return 0; |
3489 | } | |
3490 | ||
0119fee4 PZ |
3491 | /* |
3492 | * I took it apart and put it back together again, except now I have | |
3493 | * these 'spare' parts.. where shall I put them. | |
3494 | */ | |
64aa348e PZ |
3495 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3496 | return 0; | |
3497 | return 1; | |
3498 | } | |
3499 | ||
fbb9ce95 | 3500 | /* |
e0f56fd7 PZ |
3501 | * Remove the lock to the list of currently held locks - this gets |
3502 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3503 | * mutex_lock_interruptible()). | |
3504 | * | |
3505 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
3506 | */ |
3507 | static int | |
e0f56fd7 | 3508 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
fbb9ce95 | 3509 | { |
e0f56fd7 | 3510 | struct task_struct *curr = current; |
fbb9ce95 IM |
3511 | struct held_lock *hlock, *prev_hlock; |
3512 | unsigned int depth; | |
3513 | int i; | |
3514 | ||
e0f56fd7 PZ |
3515 | if (unlikely(!debug_locks)) |
3516 | return 0; | |
3517 | ||
fbb9ce95 | 3518 | depth = curr->lockdep_depth; |
0119fee4 PZ |
3519 | /* |
3520 | * So we're all set to release this lock.. wait what lock? We don't | |
3521 | * own any locks, you've been drinking again? | |
3522 | */ | |
e0f56fd7 PZ |
3523 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
3524 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3525 | |
e0f56fd7 PZ |
3526 | /* |
3527 | * Check whether the lock exists in the current stack | |
3528 | * of held locks: | |
3529 | */ | |
fbb9ce95 IM |
3530 | prev_hlock = NULL; |
3531 | for (i = depth-1; i >= 0; i--) { | |
3532 | hlock = curr->held_locks + i; | |
3533 | /* | |
3534 | * We must not cross into another context: | |
3535 | */ | |
3536 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3537 | break; | |
bb97a91e | 3538 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3539 | goto found_it; |
3540 | prev_hlock = hlock; | |
3541 | } | |
f86f7554 | 3542 | return print_unlock_imbalance_bug(curr, lock, ip); |
fbb9ce95 IM |
3543 | |
3544 | found_it: | |
bb97a91e PZ |
3545 | if (hlock->instance == lock) |
3546 | lock_release_holdtime(hlock); | |
3547 | ||
a24fc60d PZ |
3548 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
3549 | ||
bb97a91e PZ |
3550 | if (hlock->references) { |
3551 | hlock->references--; | |
3552 | if (hlock->references) { | |
3553 | /* | |
3554 | * We had, and after removing one, still have | |
3555 | * references, the current lock stack is still | |
3556 | * valid. We're done! | |
3557 | */ | |
3558 | return 1; | |
3559 | } | |
3560 | } | |
f20786ff | 3561 | |
fbb9ce95 IM |
3562 | /* |
3563 | * We have the right lock to unlock, 'hlock' points to it. | |
3564 | * Now we remove it from the stack, and add back the other | |
3565 | * entries (if any), recalculating the hash along the way: | |
3566 | */ | |
bb97a91e | 3567 | |
fbb9ce95 IM |
3568 | curr->lockdep_depth = i; |
3569 | curr->curr_chain_key = hlock->prev_chain_key; | |
3570 | ||
3571 | for (i++; i < depth; i++) { | |
3572 | hlock = curr->held_locks + i; | |
3573 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3574 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3575 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3576 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3577 | hlock->references, hlock->pin_count)) |
fbb9ce95 IM |
3578 | return 0; |
3579 | } | |
3580 | ||
0119fee4 PZ |
3581 | /* |
3582 | * We had N bottles of beer on the wall, we drank one, but now | |
3583 | * there's not N-1 bottles of beer left on the wall... | |
3584 | */ | |
fbb9ce95 IM |
3585 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3586 | return 0; | |
f20786ff | 3587 | |
fbb9ce95 IM |
3588 | return 1; |
3589 | } | |
3590 | ||
f8319483 | 3591 | static int __lock_is_held(struct lockdep_map *lock, int read) |
fbb9ce95 | 3592 | { |
f607c668 PZ |
3593 | struct task_struct *curr = current; |
3594 | int i; | |
fbb9ce95 | 3595 | |
f607c668 | 3596 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 3597 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 3598 | |
f8319483 PZ |
3599 | if (match_held_lock(hlock, lock)) { |
3600 | if (read == -1 || hlock->read == read) | |
3601 | return 1; | |
3602 | ||
3603 | return 0; | |
3604 | } | |
f607c668 | 3605 | } |
f20786ff | 3606 | |
f607c668 | 3607 | return 0; |
fbb9ce95 IM |
3608 | } |
3609 | ||
e7904a28 PZ |
3610 | static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) |
3611 | { | |
3612 | struct pin_cookie cookie = NIL_COOKIE; | |
3613 | struct task_struct *curr = current; | |
3614 | int i; | |
3615 | ||
3616 | if (unlikely(!debug_locks)) | |
3617 | return cookie; | |
3618 | ||
3619 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3620 | struct held_lock *hlock = curr->held_locks + i; | |
3621 | ||
3622 | if (match_held_lock(hlock, lock)) { | |
3623 | /* | |
3624 | * Grab 16bits of randomness; this is sufficient to not | |
3625 | * be guessable and still allows some pin nesting in | |
3626 | * our u32 pin_count. | |
3627 | */ | |
3628 | cookie.val = 1 + (prandom_u32() >> 16); | |
3629 | hlock->pin_count += cookie.val; | |
3630 | return cookie; | |
3631 | } | |
3632 | } | |
3633 | ||
3634 | WARN(1, "pinning an unheld lock\n"); | |
3635 | return cookie; | |
3636 | } | |
3637 | ||
3638 | static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
fbb9ce95 IM |
3639 | { |
3640 | struct task_struct *curr = current; | |
a24fc60d | 3641 | int i; |
fbb9ce95 | 3642 | |
a24fc60d | 3643 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
3644 | return; |
3645 | ||
a24fc60d PZ |
3646 | for (i = 0; i < curr->lockdep_depth; i++) { |
3647 | struct held_lock *hlock = curr->held_locks + i; | |
3648 | ||
3649 | if (match_held_lock(hlock, lock)) { | |
e7904a28 | 3650 | hlock->pin_count += cookie.val; |
fbb9ce95 | 3651 | return; |
a24fc60d | 3652 | } |
fbb9ce95 IM |
3653 | } |
3654 | ||
a24fc60d | 3655 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
3656 | } |
3657 | ||
e7904a28 | 3658 | static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
f607c668 PZ |
3659 | { |
3660 | struct task_struct *curr = current; | |
3661 | int i; | |
3662 | ||
a24fc60d PZ |
3663 | if (unlikely(!debug_locks)) |
3664 | return; | |
3665 | ||
f607c668 | 3666 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
3667 | struct held_lock *hlock = curr->held_locks + i; |
3668 | ||
a24fc60d PZ |
3669 | if (match_held_lock(hlock, lock)) { |
3670 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
3671 | return; | |
3672 | ||
e7904a28 PZ |
3673 | hlock->pin_count -= cookie.val; |
3674 | ||
3675 | if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n")) | |
3676 | hlock->pin_count = 0; | |
3677 | ||
a24fc60d PZ |
3678 | return; |
3679 | } | |
f607c668 PZ |
3680 | } |
3681 | ||
a24fc60d | 3682 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
3683 | } |
3684 | ||
fbb9ce95 IM |
3685 | /* |
3686 | * Check whether we follow the irq-flags state precisely: | |
3687 | */ | |
1d09daa5 | 3688 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3689 | { |
992860e9 IM |
3690 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3691 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3692 | if (!debug_locks) |
3693 | return; | |
3694 | ||
5f9fa8a6 IM |
3695 | if (irqs_disabled_flags(flags)) { |
3696 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3697 | printk("possible reason: unannotated irqs-off.\n"); | |
3698 | } | |
3699 | } else { | |
3700 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3701 | printk("possible reason: unannotated irqs-on.\n"); | |
3702 | } | |
3703 | } | |
fbb9ce95 IM |
3704 | |
3705 | /* | |
3706 | * We dont accurately track softirq state in e.g. | |
3707 | * hardirq contexts (such as on 4KSTACKS), so only | |
3708 | * check if not in hardirq contexts: | |
3709 | */ | |
3710 | if (!hardirq_count()) { | |
0119fee4 PZ |
3711 | if (softirq_count()) { |
3712 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3713 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3714 | } else { |
3715 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3716 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3717 | } |
fbb9ce95 IM |
3718 | } |
3719 | ||
3720 | if (!debug_locks) | |
3721 | print_irqtrace_events(current); | |
3722 | #endif | |
3723 | } | |
3724 | ||
00ef9f73 PZ |
3725 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3726 | struct lock_class_key *key, unsigned int subclass, | |
3727 | unsigned long ip) | |
64aa348e PZ |
3728 | { |
3729 | unsigned long flags; | |
3730 | ||
3731 | if (unlikely(current->lockdep_recursion)) | |
3732 | return; | |
3733 | ||
3734 | raw_local_irq_save(flags); | |
3735 | current->lockdep_recursion = 1; | |
3736 | check_flags(flags); | |
00ef9f73 | 3737 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3738 | check_chain_key(current); |
3739 | current->lockdep_recursion = 0; | |
3740 | raw_local_irq_restore(flags); | |
3741 | } | |
00ef9f73 | 3742 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3743 | |
fbb9ce95 IM |
3744 | /* |
3745 | * We are not always called with irqs disabled - do that here, | |
3746 | * and also avoid lockdep recursion: | |
3747 | */ | |
1d09daa5 | 3748 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3749 | int trylock, int read, int check, |
3750 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3751 | { |
3752 | unsigned long flags; | |
3753 | ||
3754 | if (unlikely(current->lockdep_recursion)) | |
3755 | return; | |
3756 | ||
3757 | raw_local_irq_save(flags); | |
3758 | check_flags(flags); | |
3759 | ||
3760 | current->lockdep_recursion = 1; | |
db2c4c77 | 3761 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3762 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 3763 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
3764 | current->lockdep_recursion = 0; |
3765 | raw_local_irq_restore(flags); | |
3766 | } | |
fbb9ce95 IM |
3767 | EXPORT_SYMBOL_GPL(lock_acquire); |
3768 | ||
1d09daa5 | 3769 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3770 | unsigned long ip) |
fbb9ce95 IM |
3771 | { |
3772 | unsigned long flags; | |
3773 | ||
3774 | if (unlikely(current->lockdep_recursion)) | |
3775 | return; | |
3776 | ||
3777 | raw_local_irq_save(flags); | |
3778 | check_flags(flags); | |
3779 | current->lockdep_recursion = 1; | |
93135439 | 3780 | trace_lock_release(lock, ip); |
e0f56fd7 PZ |
3781 | if (__lock_release(lock, nested, ip)) |
3782 | check_chain_key(current); | |
fbb9ce95 IM |
3783 | current->lockdep_recursion = 0; |
3784 | raw_local_irq_restore(flags); | |
3785 | } | |
fbb9ce95 IM |
3786 | EXPORT_SYMBOL_GPL(lock_release); |
3787 | ||
f8319483 | 3788 | int lock_is_held_type(struct lockdep_map *lock, int read) |
f607c668 PZ |
3789 | { |
3790 | unsigned long flags; | |
3791 | int ret = 0; | |
3792 | ||
3793 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3794 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3795 | |
3796 | raw_local_irq_save(flags); | |
3797 | check_flags(flags); | |
3798 | ||
3799 | current->lockdep_recursion = 1; | |
f8319483 | 3800 | ret = __lock_is_held(lock, read); |
f607c668 PZ |
3801 | current->lockdep_recursion = 0; |
3802 | raw_local_irq_restore(flags); | |
3803 | ||
3804 | return ret; | |
3805 | } | |
f8319483 | 3806 | EXPORT_SYMBOL_GPL(lock_is_held_type); |
f607c668 | 3807 | |
e7904a28 | 3808 | struct pin_cookie lock_pin_lock(struct lockdep_map *lock) |
a24fc60d | 3809 | { |
e7904a28 | 3810 | struct pin_cookie cookie = NIL_COOKIE; |
a24fc60d PZ |
3811 | unsigned long flags; |
3812 | ||
3813 | if (unlikely(current->lockdep_recursion)) | |
e7904a28 | 3814 | return cookie; |
a24fc60d PZ |
3815 | |
3816 | raw_local_irq_save(flags); | |
3817 | check_flags(flags); | |
3818 | ||
3819 | current->lockdep_recursion = 1; | |
e7904a28 | 3820 | cookie = __lock_pin_lock(lock); |
a24fc60d PZ |
3821 | current->lockdep_recursion = 0; |
3822 | raw_local_irq_restore(flags); | |
e7904a28 PZ |
3823 | |
3824 | return cookie; | |
a24fc60d PZ |
3825 | } |
3826 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
3827 | ||
e7904a28 PZ |
3828 | void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
3829 | { | |
3830 | unsigned long flags; | |
3831 | ||
3832 | if (unlikely(current->lockdep_recursion)) | |
3833 | return; | |
3834 | ||
3835 | raw_local_irq_save(flags); | |
3836 | check_flags(flags); | |
3837 | ||
3838 | current->lockdep_recursion = 1; | |
3839 | __lock_repin_lock(lock, cookie); | |
3840 | current->lockdep_recursion = 0; | |
3841 | raw_local_irq_restore(flags); | |
3842 | } | |
3843 | EXPORT_SYMBOL_GPL(lock_repin_lock); | |
3844 | ||
3845 | void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
a24fc60d PZ |
3846 | { |
3847 | unsigned long flags; | |
3848 | ||
3849 | if (unlikely(current->lockdep_recursion)) | |
3850 | return; | |
3851 | ||
3852 | raw_local_irq_save(flags); | |
3853 | check_flags(flags); | |
3854 | ||
3855 | current->lockdep_recursion = 1; | |
e7904a28 | 3856 | __lock_unpin_lock(lock, cookie); |
a24fc60d PZ |
3857 | current->lockdep_recursion = 0; |
3858 | raw_local_irq_restore(flags); | |
3859 | } | |
3860 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
3861 | ||
cf40bd16 NP |
3862 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3863 | { | |
3864 | current->lockdep_reclaim_gfp = gfp_mask; | |
3865 | } | |
3866 | ||
3867 | void lockdep_clear_current_reclaim_state(void) | |
3868 | { | |
3869 | current->lockdep_reclaim_gfp = 0; | |
3870 | } | |
3871 | ||
f20786ff PZ |
3872 | #ifdef CONFIG_LOCK_STAT |
3873 | static int | |
3874 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3875 | unsigned long ip) | |
3876 | { | |
3877 | if (!debug_locks_off()) | |
3878 | return 0; | |
3879 | if (debug_locks_silent) | |
3880 | return 0; | |
3881 | ||
b3fbab05 PM |
3882 | printk("\n"); |
3883 | printk("=================================\n"); | |
3884 | printk("[ BUG: bad contention detected! ]\n"); | |
fbdc4b9a | 3885 | print_kernel_ident(); |
b3fbab05 | 3886 | printk("---------------------------------\n"); |
f20786ff | 3887 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3888 | curr->comm, task_pid_nr(curr)); |
f20786ff | 3889 | print_lockdep_cache(lock); |
f943fe0f | 3890 | printk(KERN_CONT ") at:\n"); |
f20786ff PZ |
3891 | print_ip_sym(ip); |
3892 | printk("but there are no locks held!\n"); | |
3893 | printk("\nother info that might help us debug this:\n"); | |
3894 | lockdep_print_held_locks(curr); | |
3895 | ||
3896 | printk("\nstack backtrace:\n"); | |
3897 | dump_stack(); | |
3898 | ||
3899 | return 0; | |
3900 | } | |
3901 | ||
3902 | static void | |
3903 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3904 | { | |
3905 | struct task_struct *curr = current; | |
3906 | struct held_lock *hlock, *prev_hlock; | |
3907 | struct lock_class_stats *stats; | |
3908 | unsigned int depth; | |
c7e78cff | 3909 | int i, contention_point, contending_point; |
f20786ff PZ |
3910 | |
3911 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3912 | /* |
3913 | * Whee, we contended on this lock, except it seems we're not | |
3914 | * actually trying to acquire anything much at all.. | |
3915 | */ | |
f20786ff PZ |
3916 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3917 | return; | |
3918 | ||
3919 | prev_hlock = NULL; | |
3920 | for (i = depth-1; i >= 0; i--) { | |
3921 | hlock = curr->held_locks + i; | |
3922 | /* | |
3923 | * We must not cross into another context: | |
3924 | */ | |
3925 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3926 | break; | |
bb97a91e | 3927 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3928 | goto found_it; |
3929 | prev_hlock = hlock; | |
3930 | } | |
3931 | print_lock_contention_bug(curr, lock, ip); | |
3932 | return; | |
3933 | ||
3934 | found_it: | |
bb97a91e PZ |
3935 | if (hlock->instance != lock) |
3936 | return; | |
3937 | ||
3365e779 | 3938 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3939 | |
c7e78cff PZ |
3940 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3941 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3942 | lock->ip); | |
f20786ff | 3943 | |
f82b217e | 3944 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3945 | if (contention_point < LOCKSTAT_POINTS) |
3946 | stats->contention_point[contention_point]++; | |
3947 | if (contending_point < LOCKSTAT_POINTS) | |
3948 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3949 | if (lock->cpu != smp_processor_id()) |
3950 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3951 | put_lock_stats(stats); |
3952 | } | |
3953 | ||
3954 | static void | |
c7e78cff | 3955 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3956 | { |
3957 | struct task_struct *curr = current; | |
3958 | struct held_lock *hlock, *prev_hlock; | |
3959 | struct lock_class_stats *stats; | |
3960 | unsigned int depth; | |
3365e779 | 3961 | u64 now, waittime = 0; |
96645678 | 3962 | int i, cpu; |
f20786ff PZ |
3963 | |
3964 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3965 | /* |
3966 | * Yay, we acquired ownership of this lock we didn't try to | |
3967 | * acquire, how the heck did that happen? | |
3968 | */ | |
f20786ff PZ |
3969 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3970 | return; | |
3971 | ||
3972 | prev_hlock = NULL; | |
3973 | for (i = depth-1; i >= 0; i--) { | |
3974 | hlock = curr->held_locks + i; | |
3975 | /* | |
3976 | * We must not cross into another context: | |
3977 | */ | |
3978 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3979 | break; | |
bb97a91e | 3980 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3981 | goto found_it; |
3982 | prev_hlock = hlock; | |
3983 | } | |
3984 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3985 | return; | |
3986 | ||
3987 | found_it: | |
bb97a91e PZ |
3988 | if (hlock->instance != lock) |
3989 | return; | |
3990 | ||
96645678 PZ |
3991 | cpu = smp_processor_id(); |
3992 | if (hlock->waittime_stamp) { | |
3365e779 | 3993 | now = lockstat_clock(); |
96645678 PZ |
3994 | waittime = now - hlock->waittime_stamp; |
3995 | hlock->holdtime_stamp = now; | |
3996 | } | |
f20786ff | 3997 | |
883a2a31 | 3998 | trace_lock_acquired(lock, ip); |
2062501a | 3999 | |
f82b217e | 4000 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
4001 | if (waittime) { |
4002 | if (hlock->read) | |
4003 | lock_time_inc(&stats->read_waittime, waittime); | |
4004 | else | |
4005 | lock_time_inc(&stats->write_waittime, waittime); | |
4006 | } | |
4007 | if (lock->cpu != cpu) | |
4008 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 4009 | put_lock_stats(stats); |
96645678 PZ |
4010 | |
4011 | lock->cpu = cpu; | |
c7e78cff | 4012 | lock->ip = ip; |
f20786ff PZ |
4013 | } |
4014 | ||
4015 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4016 | { | |
4017 | unsigned long flags; | |
4018 | ||
4019 | if (unlikely(!lock_stat)) | |
4020 | return; | |
4021 | ||
4022 | if (unlikely(current->lockdep_recursion)) | |
4023 | return; | |
4024 | ||
4025 | raw_local_irq_save(flags); | |
4026 | check_flags(flags); | |
4027 | current->lockdep_recursion = 1; | |
db2c4c77 | 4028 | trace_lock_contended(lock, ip); |
f20786ff PZ |
4029 | __lock_contended(lock, ip); |
4030 | current->lockdep_recursion = 0; | |
4031 | raw_local_irq_restore(flags); | |
4032 | } | |
4033 | EXPORT_SYMBOL_GPL(lock_contended); | |
4034 | ||
c7e78cff | 4035 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4036 | { |
4037 | unsigned long flags; | |
4038 | ||
4039 | if (unlikely(!lock_stat)) | |
4040 | return; | |
4041 | ||
4042 | if (unlikely(current->lockdep_recursion)) | |
4043 | return; | |
4044 | ||
4045 | raw_local_irq_save(flags); | |
4046 | check_flags(flags); | |
4047 | current->lockdep_recursion = 1; | |
c7e78cff | 4048 | __lock_acquired(lock, ip); |
f20786ff PZ |
4049 | current->lockdep_recursion = 0; |
4050 | raw_local_irq_restore(flags); | |
4051 | } | |
4052 | EXPORT_SYMBOL_GPL(lock_acquired); | |
4053 | #endif | |
4054 | ||
fbb9ce95 IM |
4055 | /* |
4056 | * Used by the testsuite, sanitize the validator state | |
4057 | * after a simulated failure: | |
4058 | */ | |
4059 | ||
4060 | void lockdep_reset(void) | |
4061 | { | |
4062 | unsigned long flags; | |
23d95a03 | 4063 | int i; |
fbb9ce95 IM |
4064 | |
4065 | raw_local_irq_save(flags); | |
4066 | current->curr_chain_key = 0; | |
4067 | current->lockdep_depth = 0; | |
4068 | current->lockdep_recursion = 0; | |
4069 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
4070 | nr_hardirq_chains = 0; | |
4071 | nr_softirq_chains = 0; | |
4072 | nr_process_chains = 0; | |
4073 | debug_locks = 1; | |
23d95a03 | 4074 | for (i = 0; i < CHAINHASH_SIZE; i++) |
a63f38cc | 4075 | INIT_HLIST_HEAD(chainhash_table + i); |
fbb9ce95 IM |
4076 | raw_local_irq_restore(flags); |
4077 | } | |
4078 | ||
4079 | static void zap_class(struct lock_class *class) | |
4080 | { | |
4081 | int i; | |
4082 | ||
4083 | /* | |
4084 | * Remove all dependencies this lock is | |
4085 | * involved in: | |
4086 | */ | |
4087 | for (i = 0; i < nr_list_entries; i++) { | |
4088 | if (list_entries[i].class == class) | |
4089 | list_del_rcu(&list_entries[i].entry); | |
4090 | } | |
4091 | /* | |
4092 | * Unhash the class and remove it from the all_lock_classes list: | |
4093 | */ | |
a63f38cc | 4094 | hlist_del_rcu(&class->hash_entry); |
fbb9ce95 IM |
4095 | list_del_rcu(&class->lock_entry); |
4096 | ||
cee34d88 PZ |
4097 | RCU_INIT_POINTER(class->key, NULL); |
4098 | RCU_INIT_POINTER(class->name, NULL); | |
fbb9ce95 IM |
4099 | } |
4100 | ||
fabe874a | 4101 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
4102 | { |
4103 | return addr >= start && addr < start + size; | |
4104 | } | |
4105 | ||
35a9393c PZ |
4106 | /* |
4107 | * Used in module.c to remove lock classes from memory that is going to be | |
4108 | * freed; and possibly re-used by other modules. | |
4109 | * | |
4110 | * We will have had one sync_sched() before getting here, so we're guaranteed | |
4111 | * nobody will look up these exact classes -- they're properly dead but still | |
4112 | * allocated. | |
4113 | */ | |
fbb9ce95 IM |
4114 | void lockdep_free_key_range(void *start, unsigned long size) |
4115 | { | |
35a9393c | 4116 | struct lock_class *class; |
a63f38cc | 4117 | struct hlist_head *head; |
fbb9ce95 IM |
4118 | unsigned long flags; |
4119 | int i; | |
5a26db5b | 4120 | int locked; |
fbb9ce95 IM |
4121 | |
4122 | raw_local_irq_save(flags); | |
5a26db5b | 4123 | locked = graph_lock(); |
fbb9ce95 IM |
4124 | |
4125 | /* | |
4126 | * Unhash all classes that were created by this module: | |
4127 | */ | |
4128 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
4129 | head = classhash_table + i; | |
a63f38cc | 4130 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
fbb9ce95 IM |
4131 | if (within(class->key, start, size)) |
4132 | zap_class(class); | |
fabe874a AV |
4133 | else if (within(class->name, start, size)) |
4134 | zap_class(class); | |
4135 | } | |
fbb9ce95 IM |
4136 | } |
4137 | ||
5a26db5b NP |
4138 | if (locked) |
4139 | graph_unlock(); | |
fbb9ce95 | 4140 | raw_local_irq_restore(flags); |
35a9393c PZ |
4141 | |
4142 | /* | |
4143 | * Wait for any possible iterators from look_up_lock_class() to pass | |
4144 | * before continuing to free the memory they refer to. | |
4145 | * | |
4146 | * sync_sched() is sufficient because the read-side is IRQ disable. | |
4147 | */ | |
4148 | synchronize_sched(); | |
4149 | ||
4150 | /* | |
4151 | * XXX at this point we could return the resources to the pool; | |
4152 | * instead we leak them. We would need to change to bitmap allocators | |
4153 | * instead of the linear allocators we have now. | |
4154 | */ | |
fbb9ce95 IM |
4155 | } |
4156 | ||
4157 | void lockdep_reset_lock(struct lockdep_map *lock) | |
4158 | { | |
35a9393c | 4159 | struct lock_class *class; |
a63f38cc | 4160 | struct hlist_head *head; |
fbb9ce95 IM |
4161 | unsigned long flags; |
4162 | int i, j; | |
5a26db5b | 4163 | int locked; |
fbb9ce95 IM |
4164 | |
4165 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
4166 | |
4167 | /* | |
d6d897ce IM |
4168 | * Remove all classes this lock might have: |
4169 | */ | |
4170 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
4171 | /* | |
4172 | * If the class exists we look it up and zap it: | |
4173 | */ | |
4174 | class = look_up_lock_class(lock, j); | |
4175 | if (class) | |
4176 | zap_class(class); | |
4177 | } | |
4178 | /* | |
4179 | * Debug check: in the end all mapped classes should | |
4180 | * be gone. | |
fbb9ce95 | 4181 | */ |
5a26db5b | 4182 | locked = graph_lock(); |
fbb9ce95 IM |
4183 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
4184 | head = classhash_table + i; | |
a63f38cc | 4185 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
62016250 HM |
4186 | int match = 0; |
4187 | ||
4188 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
4189 | match |= class == lock->class_cache[j]; | |
4190 | ||
4191 | if (unlikely(match)) { | |
0119fee4 PZ |
4192 | if (debug_locks_off_graph_unlock()) { |
4193 | /* | |
4194 | * We all just reset everything, how did it match? | |
4195 | */ | |
74c383f1 | 4196 | WARN_ON(1); |
0119fee4 | 4197 | } |
d6d897ce | 4198 | goto out_restore; |
fbb9ce95 IM |
4199 | } |
4200 | } | |
4201 | } | |
5a26db5b NP |
4202 | if (locked) |
4203 | graph_unlock(); | |
d6d897ce IM |
4204 | |
4205 | out_restore: | |
fbb9ce95 IM |
4206 | raw_local_irq_restore(flags); |
4207 | } | |
4208 | ||
fbb9ce95 IM |
4209 | void __init lockdep_info(void) |
4210 | { | |
4211 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
4212 | ||
b0788caf | 4213 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
4214 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
4215 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 4216 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
4217 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
4218 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
4219 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
4220 | ||
4221 | printk(" memory used by lock dependency info: %lu kB\n", | |
4222 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
4223 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
4224 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
4225 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 4226 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 4227 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 4228 | + sizeof(struct circular_queue) |
4dd861d6 | 4229 | #endif |
90629209 | 4230 | ) / 1024 |
4dd861d6 | 4231 | ); |
fbb9ce95 IM |
4232 | |
4233 | printk(" per task-struct memory footprint: %lu bytes\n", | |
4234 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
fbb9ce95 IM |
4235 | } |
4236 | ||
fbb9ce95 IM |
4237 | static void |
4238 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 4239 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
4240 | { |
4241 | if (!debug_locks_off()) | |
4242 | return; | |
4243 | if (debug_locks_silent) | |
4244 | return; | |
4245 | ||
b3fbab05 PM |
4246 | printk("\n"); |
4247 | printk("=========================\n"); | |
4248 | printk("[ BUG: held lock freed! ]\n"); | |
fbdc4b9a | 4249 | print_kernel_ident(); |
b3fbab05 | 4250 | printk("-------------------------\n"); |
fbb9ce95 | 4251 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 4252 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 4253 | print_lock(hlock); |
fbb9ce95 IM |
4254 | lockdep_print_held_locks(curr); |
4255 | ||
4256 | printk("\nstack backtrace:\n"); | |
4257 | dump_stack(); | |
4258 | } | |
4259 | ||
54561783 ON |
4260 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4261 | const void* lock_from, unsigned long lock_len) | |
4262 | { | |
4263 | return lock_from + lock_len <= mem_from || | |
4264 | mem_from + mem_len <= lock_from; | |
4265 | } | |
4266 | ||
fbb9ce95 IM |
4267 | /* |
4268 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4269 | * is destroyed or reinitialized - this code checks whether there is | |
4270 | * any held lock in the memory range of <from> to <to>: | |
4271 | */ | |
4272 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4273 | { | |
fbb9ce95 IM |
4274 | struct task_struct *curr = current; |
4275 | struct held_lock *hlock; | |
4276 | unsigned long flags; | |
4277 | int i; | |
4278 | ||
4279 | if (unlikely(!debug_locks)) | |
4280 | return; | |
4281 | ||
4282 | local_irq_save(flags); | |
4283 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4284 | hlock = curr->held_locks + i; | |
4285 | ||
54561783 ON |
4286 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4287 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4288 | continue; |
4289 | ||
54561783 | 4290 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4291 | break; |
4292 | } | |
4293 | local_irq_restore(flags); | |
4294 | } | |
ed07536e | 4295 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 4296 | |
1b1d2fb4 | 4297 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
4298 | { |
4299 | if (!debug_locks_off()) | |
4300 | return; | |
4301 | if (debug_locks_silent) | |
4302 | return; | |
4303 | ||
b3fbab05 PM |
4304 | printk("\n"); |
4305 | printk("=====================================\n"); | |
1b1d2fb4 CC |
4306 | printk("[ BUG: %s/%d still has locks held! ]\n", |
4307 | current->comm, task_pid_nr(current)); | |
fbdc4b9a | 4308 | print_kernel_ident(); |
b3fbab05 | 4309 | printk("-------------------------------------\n"); |
1b1d2fb4 | 4310 | lockdep_print_held_locks(current); |
fbb9ce95 IM |
4311 | printk("\nstack backtrace:\n"); |
4312 | dump_stack(); | |
4313 | } | |
4314 | ||
1b1d2fb4 | 4315 | void debug_check_no_locks_held(void) |
fbb9ce95 | 4316 | { |
1b1d2fb4 CC |
4317 | if (unlikely(current->lockdep_depth > 0)) |
4318 | print_held_locks_bug(); | |
fbb9ce95 | 4319 | } |
1b1d2fb4 | 4320 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 4321 | |
8dce7a9a | 4322 | #ifdef __KERNEL__ |
fbb9ce95 IM |
4323 | void debug_show_all_locks(void) |
4324 | { | |
4325 | struct task_struct *g, *p; | |
4326 | int count = 10; | |
4327 | int unlock = 1; | |
4328 | ||
9c35dd7f JP |
4329 | if (unlikely(!debug_locks)) { |
4330 | printk("INFO: lockdep is turned off.\n"); | |
4331 | return; | |
4332 | } | |
fbb9ce95 IM |
4333 | printk("\nShowing all locks held in the system:\n"); |
4334 | ||
4335 | /* | |
4336 | * Here we try to get the tasklist_lock as hard as possible, | |
4337 | * if not successful after 2 seconds we ignore it (but keep | |
4338 | * trying). This is to enable a debug printout even if a | |
4339 | * tasklist_lock-holding task deadlocks or crashes. | |
4340 | */ | |
4341 | retry: | |
4342 | if (!read_trylock(&tasklist_lock)) { | |
4343 | if (count == 10) | |
4344 | printk("hm, tasklist_lock locked, retrying... "); | |
4345 | if (count) { | |
4346 | count--; | |
4347 | printk(" #%d", 10-count); | |
4348 | mdelay(200); | |
4349 | goto retry; | |
4350 | } | |
4351 | printk(" ignoring it.\n"); | |
4352 | unlock = 0; | |
46fec7ac | 4353 | } else { |
4354 | if (count != 10) | |
4355 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 4356 | } |
fbb9ce95 IM |
4357 | |
4358 | do_each_thread(g, p) { | |
85684873 IM |
4359 | /* |
4360 | * It's not reliable to print a task's held locks | |
4361 | * if it's not sleeping (or if it's not the current | |
4362 | * task): | |
4363 | */ | |
4364 | if (p->state == TASK_RUNNING && p != current) | |
4365 | continue; | |
fbb9ce95 IM |
4366 | if (p->lockdep_depth) |
4367 | lockdep_print_held_locks(p); | |
4368 | if (!unlock) | |
4369 | if (read_trylock(&tasklist_lock)) | |
4370 | unlock = 1; | |
4371 | } while_each_thread(g, p); | |
4372 | ||
4373 | printk("\n"); | |
4374 | printk("=============================================\n\n"); | |
4375 | ||
4376 | if (unlock) | |
4377 | read_unlock(&tasklist_lock); | |
4378 | } | |
fbb9ce95 | 4379 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 4380 | #endif |
fbb9ce95 | 4381 | |
82a1fcb9 IM |
4382 | /* |
4383 | * Careful: only use this function if you are sure that | |
4384 | * the task cannot run in parallel! | |
4385 | */ | |
f1b499f0 | 4386 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4387 | { |
9c35dd7f JP |
4388 | if (unlikely(!debug_locks)) { |
4389 | printk("INFO: lockdep is turned off.\n"); | |
4390 | return; | |
4391 | } | |
fbb9ce95 IM |
4392 | lockdep_print_held_locks(task); |
4393 | } | |
fbb9ce95 | 4394 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 4395 | |
722a9f92 | 4396 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
4397 | { |
4398 | struct task_struct *curr = current; | |
4399 | ||
4400 | if (unlikely(curr->lockdep_depth)) { | |
4401 | if (!debug_locks_off()) | |
4402 | return; | |
b3fbab05 PM |
4403 | printk("\n"); |
4404 | printk("================================================\n"); | |
4405 | printk("[ BUG: lock held when returning to user space! ]\n"); | |
fbdc4b9a | 4406 | print_kernel_ident(); |
b3fbab05 | 4407 | printk("------------------------------------------------\n"); |
b351d164 PZ |
4408 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4409 | curr->comm, curr->pid); | |
4410 | lockdep_print_held_locks(curr); | |
4411 | } | |
4412 | } | |
0632eb3d | 4413 | |
b3fbab05 | 4414 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4415 | { |
4416 | struct task_struct *curr = current; | |
4417 | ||
2b3fc35f | 4418 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4419 | if (!debug_locks_off()) |
4420 | return; | |
2b3fc35f LJ |
4421 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4422 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 | 4423 | printk("\n"); |
4d4f88fa PM |
4424 | pr_err("===============================\n"); |
4425 | pr_err("[ ERR: suspicious RCU usage. ]\n"); | |
fbdc4b9a | 4426 | print_kernel_ident(); |
4d4f88fa PM |
4427 | pr_err("-------------------------------\n"); |
4428 | pr_err("%s:%d %s!\n", file, line, s); | |
4429 | pr_err("\nother info that might help us debug this:\n\n"); | |
4430 | pr_err("\n%srcu_scheduler_active = %d, debug_locks = %d\n", | |
c5fdcec9 PM |
4431 | !rcu_lockdep_current_cpu_online() |
4432 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 4433 | : !rcu_is_watching() |
c5fdcec9 PM |
4434 | ? "RCU used illegally from idle CPU!\n" |
4435 | : "", | |
4436 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
4437 | |
4438 | /* | |
4439 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
4440 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
4441 | * considers that CPU to be in an "extended quiescent state", | |
4442 | * which means that RCU will be completely ignoring that CPU. | |
4443 | * Therefore, rcu_read_lock() and friends have absolutely no | |
4444 | * effect on a CPU running in that state. In other words, even if | |
4445 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
4446 | * delete data structures out from under it. RCU really has no | |
4447 | * choice here: we need to keep an RCU-free window in idle where | |
4448 | * the CPU may possibly enter into low power mode. This way we can | |
4449 | * notice an extended quiescent state to other CPUs that started a grace | |
4450 | * period. Otherwise we would delay any grace period as long as we run | |
4451 | * in the idle task. | |
4452 | * | |
4453 | * So complain bitterly if someone does call rcu_read_lock(), | |
4454 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
4455 | */ | |
5c173eb8 | 4456 | if (!rcu_is_watching()) |
0464e937 FW |
4457 | printk("RCU used illegally from extended quiescent state!\n"); |
4458 | ||
0632eb3d PM |
4459 | lockdep_print_held_locks(curr); |
4460 | printk("\nstack backtrace:\n"); | |
4461 | dump_stack(); | |
4462 | } | |
b3fbab05 | 4463 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |