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> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
d3d03d4f | 47 | #include <linux/kmemcheck.h> |
af012961 | 48 | |
fbb9ce95 IM |
49 | #include <asm/sections.h> |
50 | ||
51 | #include "lockdep_internals.h" | |
52 | ||
a8d154b0 | 53 | #define CREATE_TRACE_POINTS |
67178767 | 54 | #include <trace/events/lock.h> |
a8d154b0 | 55 | |
f20786ff PZ |
56 | #ifdef CONFIG_PROVE_LOCKING |
57 | int prove_locking = 1; | |
58 | module_param(prove_locking, int, 0644); | |
59 | #else | |
60 | #define prove_locking 0 | |
61 | #endif | |
62 | ||
63 | #ifdef CONFIG_LOCK_STAT | |
64 | int lock_stat = 1; | |
65 | module_param(lock_stat, int, 0644); | |
66 | #else | |
67 | #define lock_stat 0 | |
68 | #endif | |
69 | ||
fbb9ce95 | 70 | /* |
74c383f1 IM |
71 | * lockdep_lock: protects the lockdep graph, the hashes and the |
72 | * class/list/hash allocators. | |
fbb9ce95 IM |
73 | * |
74 | * This is one of the rare exceptions where it's justified | |
75 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 76 | * code to recurse back into the lockdep code... |
fbb9ce95 | 77 | */ |
edc35bd7 | 78 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
79 | |
80 | static int graph_lock(void) | |
81 | { | |
0199c4e6 | 82 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
83 | /* |
84 | * Make sure that if another CPU detected a bug while | |
85 | * walking the graph we dont change it (while the other | |
86 | * CPU is busy printing out stuff with the graph lock | |
87 | * dropped already) | |
88 | */ | |
89 | if (!debug_locks) { | |
0199c4e6 | 90 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
91 | return 0; |
92 | } | |
bb065afb SR |
93 | /* prevent any recursions within lockdep from causing deadlocks */ |
94 | current->lockdep_recursion++; | |
74c383f1 IM |
95 | return 1; |
96 | } | |
97 | ||
98 | static inline int graph_unlock(void) | |
99 | { | |
0119fee4 PZ |
100 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
101 | /* | |
102 | * The lockdep graph lock isn't locked while we expect it to | |
103 | * be, we're confused now, bye! | |
104 | */ | |
381a2292 | 105 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 106 | } |
381a2292 | 107 | |
bb065afb | 108 | current->lockdep_recursion--; |
0199c4e6 | 109 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
110 | return 0; |
111 | } | |
112 | ||
113 | /* | |
114 | * Turn lock debugging off and return with 0 if it was off already, | |
115 | * and also release the graph lock: | |
116 | */ | |
117 | static inline int debug_locks_off_graph_unlock(void) | |
118 | { | |
119 | int ret = debug_locks_off(); | |
120 | ||
0199c4e6 | 121 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
122 | |
123 | return ret; | |
124 | } | |
fbb9ce95 | 125 | |
fbb9ce95 | 126 | unsigned long nr_list_entries; |
af012961 | 127 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 128 | |
fbb9ce95 IM |
129 | /* |
130 | * All data structures here are protected by the global debug_lock. | |
131 | * | |
132 | * Mutex key structs only get allocated, once during bootup, and never | |
133 | * get freed - this significantly simplifies the debugging code. | |
134 | */ | |
135 | unsigned long nr_lock_classes; | |
136 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
137 | ||
f82b217e DJ |
138 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
139 | { | |
140 | if (!hlock->class_idx) { | |
0119fee4 PZ |
141 | /* |
142 | * Someone passed in garbage, we give up. | |
143 | */ | |
f82b217e DJ |
144 | DEBUG_LOCKS_WARN_ON(1); |
145 | return NULL; | |
146 | } | |
147 | return lock_classes + hlock->class_idx - 1; | |
148 | } | |
149 | ||
f20786ff | 150 | #ifdef CONFIG_LOCK_STAT |
25528213 | 151 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
f20786ff | 152 | |
3365e779 PZ |
153 | static inline u64 lockstat_clock(void) |
154 | { | |
c676329a | 155 | return local_clock(); |
3365e779 PZ |
156 | } |
157 | ||
c7e78cff | 158 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
159 | { |
160 | int i; | |
161 | ||
c7e78cff PZ |
162 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
163 | if (points[i] == 0) { | |
164 | points[i] = ip; | |
f20786ff PZ |
165 | break; |
166 | } | |
c7e78cff | 167 | if (points[i] == ip) |
f20786ff PZ |
168 | break; |
169 | } | |
170 | ||
171 | return i; | |
172 | } | |
173 | ||
3365e779 | 174 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
175 | { |
176 | if (time > lt->max) | |
177 | lt->max = time; | |
178 | ||
109d71c6 | 179 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
180 | lt->min = time; |
181 | ||
182 | lt->total += time; | |
183 | lt->nr++; | |
184 | } | |
185 | ||
c46261de PZ |
186 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
187 | { | |
109d71c6 FR |
188 | if (!src->nr) |
189 | return; | |
190 | ||
191 | if (src->max > dst->max) | |
192 | dst->max = src->max; | |
193 | ||
194 | if (src->min < dst->min || !dst->nr) | |
195 | dst->min = src->min; | |
196 | ||
c46261de PZ |
197 | dst->total += src->total; |
198 | dst->nr += src->nr; | |
199 | } | |
200 | ||
201 | struct lock_class_stats lock_stats(struct lock_class *class) | |
202 | { | |
203 | struct lock_class_stats stats; | |
204 | int cpu, i; | |
205 | ||
206 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
207 | for_each_possible_cpu(cpu) { | |
208 | struct lock_class_stats *pcs = | |
1871e52c | 209 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
210 | |
211 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
212 | stats.contention_point[i] += pcs->contention_point[i]; | |
213 | ||
c7e78cff PZ |
214 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
215 | stats.contending_point[i] += pcs->contending_point[i]; | |
216 | ||
c46261de PZ |
217 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
218 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
219 | ||
220 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
221 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
222 | |
223 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
224 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
225 | } |
226 | ||
227 | return stats; | |
228 | } | |
229 | ||
230 | void clear_lock_stats(struct lock_class *class) | |
231 | { | |
232 | int cpu; | |
233 | ||
234 | for_each_possible_cpu(cpu) { | |
235 | struct lock_class_stats *cpu_stats = | |
1871e52c | 236 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
237 | |
238 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
239 | } | |
240 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 241 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
242 | } |
243 | ||
f20786ff PZ |
244 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
245 | { | |
1871e52c | 246 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
247 | } |
248 | ||
249 | static void put_lock_stats(struct lock_class_stats *stats) | |
250 | { | |
1871e52c | 251 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
252 | } |
253 | ||
254 | static void lock_release_holdtime(struct held_lock *hlock) | |
255 | { | |
256 | struct lock_class_stats *stats; | |
3365e779 | 257 | u64 holdtime; |
f20786ff PZ |
258 | |
259 | if (!lock_stat) | |
260 | return; | |
261 | ||
3365e779 | 262 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 263 | |
f82b217e | 264 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
265 | if (hlock->read) |
266 | lock_time_inc(&stats->read_holdtime, holdtime); | |
267 | else | |
268 | lock_time_inc(&stats->write_holdtime, holdtime); | |
269 | put_lock_stats(stats); | |
270 | } | |
271 | #else | |
272 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
273 | { | |
274 | } | |
275 | #endif | |
276 | ||
fbb9ce95 IM |
277 | /* |
278 | * We keep a global list of all lock classes. The list only grows, | |
279 | * never shrinks. The list is only accessed with the lockdep | |
280 | * spinlock lock held. | |
281 | */ | |
282 | LIST_HEAD(all_lock_classes); | |
283 | ||
284 | /* | |
285 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
286 | */ | |
287 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
288 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 289 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
290 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
291 | ||
a63f38cc | 292 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
fbb9ce95 | 293 | |
fbb9ce95 IM |
294 | /* |
295 | * We put the lock dependency chains into a hash-table as well, to cache | |
296 | * their existence: | |
297 | */ | |
298 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
299 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 300 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
301 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
302 | ||
a63f38cc | 303 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
fbb9ce95 IM |
304 | |
305 | /* | |
306 | * The hash key of the lock dependency chains is a hash itself too: | |
307 | * it's a hash of all locks taken up to that lock, including that lock. | |
308 | * It's a 64-bit hash, because it's important for the keys to be | |
309 | * unique. | |
310 | */ | |
311 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
312 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
313 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
314 | (key2)) |
315 | ||
1d09daa5 | 316 | void lockdep_off(void) |
fbb9ce95 IM |
317 | { |
318 | current->lockdep_recursion++; | |
319 | } | |
fbb9ce95 IM |
320 | EXPORT_SYMBOL(lockdep_off); |
321 | ||
1d09daa5 | 322 | void lockdep_on(void) |
fbb9ce95 IM |
323 | { |
324 | current->lockdep_recursion--; | |
325 | } | |
fbb9ce95 IM |
326 | EXPORT_SYMBOL(lockdep_on); |
327 | ||
fbb9ce95 IM |
328 | /* |
329 | * Debugging switches: | |
330 | */ | |
331 | ||
332 | #define VERBOSE 0 | |
33e94e96 | 333 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
334 | |
335 | #if VERBOSE | |
336 | # define HARDIRQ_VERBOSE 1 | |
337 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 338 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
339 | #else |
340 | # define HARDIRQ_VERBOSE 0 | |
341 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 342 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
343 | #endif |
344 | ||
cf40bd16 | 345 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
346 | /* |
347 | * Quick filtering for interesting events: | |
348 | */ | |
349 | static int class_filter(struct lock_class *class) | |
350 | { | |
f9829cce AK |
351 | #if 0 |
352 | /* Example */ | |
fbb9ce95 | 353 | if (class->name_version == 1 && |
f9829cce | 354 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
355 | return 1; |
356 | if (class->name_version == 1 && | |
f9829cce | 357 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 358 | return 1; |
f9829cce | 359 | #endif |
a6640897 IM |
360 | /* Filter everything else. 1 would be to allow everything else */ |
361 | return 0; | |
fbb9ce95 IM |
362 | } |
363 | #endif | |
364 | ||
365 | static int verbose(struct lock_class *class) | |
366 | { | |
367 | #if VERBOSE | |
368 | return class_filter(class); | |
369 | #endif | |
370 | return 0; | |
371 | } | |
372 | ||
fbb9ce95 IM |
373 | /* |
374 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 375 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
376 | */ |
377 | unsigned long nr_stack_trace_entries; | |
378 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
379 | ||
2c522836 DJ |
380 | static void print_lockdep_off(const char *bug_msg) |
381 | { | |
382 | printk(KERN_DEBUG "%s\n", bug_msg); | |
383 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 384 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 385 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 386 | #endif |
2c522836 DJ |
387 | } |
388 | ||
fbb9ce95 IM |
389 | static int save_trace(struct stack_trace *trace) |
390 | { | |
391 | trace->nr_entries = 0; | |
392 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
393 | trace->entries = stack_trace + nr_stack_trace_entries; | |
394 | ||
5a1b3999 | 395 | trace->skip = 3; |
5a1b3999 | 396 | |
ab1b6f03 | 397 | save_stack_trace(trace); |
fbb9ce95 | 398 | |
4f84f433 PZ |
399 | /* |
400 | * Some daft arches put -1 at the end to indicate its a full trace. | |
401 | * | |
402 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
403 | * complete trace that maxes out the entries provided will be reported | |
404 | * as incomplete, friggin useless </rant> | |
405 | */ | |
ea5b41f9 LT |
406 | if (trace->nr_entries != 0 && |
407 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
408 | trace->nr_entries--; |
409 | ||
fbb9ce95 IM |
410 | trace->max_entries = trace->nr_entries; |
411 | ||
412 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 413 | |
4f84f433 | 414 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
415 | if (!debug_locks_off_graph_unlock()) |
416 | return 0; | |
417 | ||
2c522836 | 418 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
419 | dump_stack(); |
420 | ||
fbb9ce95 IM |
421 | return 0; |
422 | } | |
423 | ||
424 | return 1; | |
425 | } | |
426 | ||
427 | unsigned int nr_hardirq_chains; | |
428 | unsigned int nr_softirq_chains; | |
429 | unsigned int nr_process_chains; | |
430 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
431 | |
432 | #ifdef CONFIG_DEBUG_LOCKDEP | |
fbb9ce95 IM |
433 | /* |
434 | * Various lockdep statistics: | |
435 | */ | |
bd6d29c2 | 436 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
437 | #endif |
438 | ||
439 | /* | |
440 | * Locking printouts: | |
441 | */ | |
442 | ||
fabe9c42 | 443 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
444 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
445 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
446 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
447 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 448 | |
fbb9ce95 IM |
449 | static const char *usage_str[] = |
450 | { | |
fabe9c42 PZ |
451 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
452 | #include "lockdep_states.h" | |
453 | #undef LOCKDEP_STATE | |
454 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
455 | }; |
456 | ||
457 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
458 | { | |
ffb45122 | 459 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
460 | } |
461 | ||
3ff176ca | 462 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 463 | { |
3ff176ca PZ |
464 | return 1UL << bit; |
465 | } | |
fbb9ce95 | 466 | |
3ff176ca PZ |
467 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
468 | { | |
469 | char c = '.'; | |
470 | ||
471 | if (class->usage_mask & lock_flag(bit + 2)) | |
472 | c = '+'; | |
473 | if (class->usage_mask & lock_flag(bit)) { | |
474 | c = '-'; | |
475 | if (class->usage_mask & lock_flag(bit + 2)) | |
476 | c = '?'; | |
fbb9ce95 IM |
477 | } |
478 | ||
3ff176ca PZ |
479 | return c; |
480 | } | |
cf40bd16 | 481 | |
f510b233 | 482 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 483 | { |
f510b233 | 484 | int i = 0; |
cf40bd16 | 485 | |
f510b233 PZ |
486 | #define LOCKDEP_STATE(__STATE) \ |
487 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
488 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
489 | #include "lockdep_states.h" | |
490 | #undef LOCKDEP_STATE | |
491 | ||
492 | usage[i] = '\0'; | |
fbb9ce95 IM |
493 | } |
494 | ||
e5e78d08 | 495 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
496 | { |
497 | char str[KSYM_NAME_LEN]; | |
498 | const char *name; | |
499 | ||
fbb9ce95 IM |
500 | name = class->name; |
501 | if (!name) { | |
502 | name = __get_key_name(class->key, str); | |
e5e78d08 | 503 | printk("%s", name); |
fbb9ce95 | 504 | } else { |
e5e78d08 | 505 | printk("%s", name); |
fbb9ce95 IM |
506 | if (class->name_version > 1) |
507 | printk("#%d", class->name_version); | |
508 | if (class->subclass) | |
509 | printk("/%d", class->subclass); | |
510 | } | |
e5e78d08 SR |
511 | } |
512 | ||
513 | static void print_lock_name(struct lock_class *class) | |
514 | { | |
515 | char usage[LOCK_USAGE_CHARS]; | |
516 | ||
517 | get_usage_chars(class, usage); | |
518 | ||
519 | printk(" ("); | |
520 | __print_lock_name(class); | |
f510b233 | 521 | printk("){%s}", usage); |
fbb9ce95 IM |
522 | } |
523 | ||
524 | static void print_lockdep_cache(struct lockdep_map *lock) | |
525 | { | |
526 | const char *name; | |
9281acea | 527 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
528 | |
529 | name = lock->name; | |
530 | if (!name) | |
531 | name = __get_key_name(lock->key->subkeys, str); | |
532 | ||
533 | printk("%s", name); | |
534 | } | |
535 | ||
536 | static void print_lock(struct held_lock *hlock) | |
537 | { | |
d7bc3197 PZ |
538 | /* |
539 | * We can be called locklessly through debug_show_all_locks() so be | |
540 | * extra careful, the hlock might have been released and cleared. | |
541 | */ | |
542 | unsigned int class_idx = hlock->class_idx; | |
543 | ||
544 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ | |
545 | barrier(); | |
546 | ||
547 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { | |
548 | printk("<RELEASED>\n"); | |
549 | return; | |
550 | } | |
551 | ||
552 | print_lock_name(lock_classes + class_idx - 1); | |
fbb9ce95 IM |
553 | printk(", at: "); |
554 | print_ip_sym(hlock->acquire_ip); | |
555 | } | |
556 | ||
557 | static void lockdep_print_held_locks(struct task_struct *curr) | |
558 | { | |
559 | int i, depth = curr->lockdep_depth; | |
560 | ||
561 | if (!depth) { | |
ba25f9dc | 562 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
563 | return; |
564 | } | |
565 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 566 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
567 | |
568 | for (i = 0; i < depth; i++) { | |
569 | printk(" #%d: ", i); | |
570 | print_lock(curr->held_locks + i); | |
571 | } | |
572 | } | |
fbb9ce95 | 573 | |
fbdc4b9a | 574 | static void print_kernel_ident(void) |
8e18257d | 575 | { |
fbdc4b9a | 576 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 577 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
578 | init_utsname()->version, |
579 | print_tainted()); | |
8e18257d PZ |
580 | } |
581 | ||
582 | static int very_verbose(struct lock_class *class) | |
583 | { | |
584 | #if VERY_VERBOSE | |
585 | return class_filter(class); | |
586 | #endif | |
587 | return 0; | |
588 | } | |
589 | ||
fbb9ce95 | 590 | /* |
8e18257d | 591 | * Is this the address of a static object: |
fbb9ce95 | 592 | */ |
8dce7a9a | 593 | #ifdef __KERNEL__ |
8e18257d | 594 | static int static_obj(void *obj) |
fbb9ce95 | 595 | { |
8e18257d PZ |
596 | unsigned long start = (unsigned long) &_stext, |
597 | end = (unsigned long) &_end, | |
598 | addr = (unsigned long) obj; | |
8e18257d | 599 | |
fbb9ce95 | 600 | /* |
8e18257d | 601 | * static variable? |
fbb9ce95 | 602 | */ |
8e18257d PZ |
603 | if ((addr >= start) && (addr < end)) |
604 | return 1; | |
fbb9ce95 | 605 | |
2a9ad18d MF |
606 | if (arch_is_kernel_data(addr)) |
607 | return 1; | |
608 | ||
fbb9ce95 | 609 | /* |
10fad5e4 | 610 | * in-kernel percpu var? |
fbb9ce95 | 611 | */ |
10fad5e4 TH |
612 | if (is_kernel_percpu_address(addr)) |
613 | return 1; | |
fbb9ce95 | 614 | |
8e18257d | 615 | /* |
10fad5e4 | 616 | * module static or percpu var? |
8e18257d | 617 | */ |
10fad5e4 | 618 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 619 | } |
8dce7a9a | 620 | #endif |
99de055a | 621 | |
fbb9ce95 | 622 | /* |
8e18257d PZ |
623 | * To make lock name printouts unique, we calculate a unique |
624 | * class->name_version generation counter: | |
fbb9ce95 | 625 | */ |
8e18257d | 626 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 627 | { |
8e18257d PZ |
628 | struct lock_class *class; |
629 | int count = 0; | |
fbb9ce95 | 630 | |
8e18257d | 631 | if (!new_class->name) |
fbb9ce95 IM |
632 | return 0; |
633 | ||
35a9393c | 634 | list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
635 | if (new_class->key - new_class->subclass == class->key) |
636 | return class->name_version; | |
637 | if (class->name && !strcmp(class->name, new_class->name)) | |
638 | count = max(count, class->name_version); | |
639 | } | |
fbb9ce95 | 640 | |
8e18257d | 641 | return count + 1; |
fbb9ce95 IM |
642 | } |
643 | ||
8e18257d PZ |
644 | /* |
645 | * Register a lock's class in the hash-table, if the class is not present | |
646 | * yet. Otherwise we look it up. We cache the result in the lock object | |
647 | * itself, so actual lookup of the hash should be once per lock object. | |
648 | */ | |
649 | static inline struct lock_class * | |
650 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 651 | { |
8e18257d | 652 | struct lockdep_subclass_key *key; |
a63f38cc | 653 | struct hlist_head *hash_head; |
8e18257d | 654 | struct lock_class *class; |
fbb9ce95 | 655 | |
4ba053c0 HM |
656 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
657 | debug_locks_off(); | |
658 | printk(KERN_ERR | |
659 | "BUG: looking up invalid subclass: %u\n", subclass); | |
660 | printk(KERN_ERR | |
661 | "turning off the locking correctness validator.\n"); | |
662 | dump_stack(); | |
663 | return NULL; | |
664 | } | |
665 | ||
8e18257d PZ |
666 | /* |
667 | * Static locks do not have their class-keys yet - for them the key | |
668 | * is the lock object itself: | |
669 | */ | |
670 | if (unlikely(!lock->key)) | |
671 | lock->key = (void *)lock; | |
fbb9ce95 | 672 | |
8e18257d PZ |
673 | /* |
674 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
675 | * lock_class_key variable is passed in through the mutex_init() | |
676 | * (or spin_lock_init()) call - which acts as the key. For static | |
677 | * locks we use the lock object itself as the key. | |
678 | */ | |
4b32d0a4 PZ |
679 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
680 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 681 | |
8e18257d | 682 | key = lock->key->subkeys + subclass; |
ca268c69 | 683 | |
8e18257d | 684 | hash_head = classhashentry(key); |
74c383f1 | 685 | |
8e18257d | 686 | /* |
35a9393c | 687 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 688 | */ |
35a9393c PZ |
689 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
690 | return NULL; | |
691 | ||
a63f38cc | 692 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
4b32d0a4 | 693 | if (class->key == key) { |
0119fee4 PZ |
694 | /* |
695 | * Huh! same key, different name? Did someone trample | |
696 | * on some memory? We're most confused. | |
697 | */ | |
4b32d0a4 | 698 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 699 | return class; |
4b32d0a4 PZ |
700 | } |
701 | } | |
fbb9ce95 | 702 | |
8e18257d | 703 | return NULL; |
fbb9ce95 IM |
704 | } |
705 | ||
706 | /* | |
8e18257d PZ |
707 | * Register a lock's class in the hash-table, if the class is not present |
708 | * yet. Otherwise we look it up. We cache the result in the lock object | |
709 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 710 | */ |
8e18257d PZ |
711 | static inline struct lock_class * |
712 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 713 | { |
8e18257d | 714 | struct lockdep_subclass_key *key; |
a63f38cc | 715 | struct hlist_head *hash_head; |
8e18257d | 716 | struct lock_class *class; |
35a9393c PZ |
717 | |
718 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
719 | |
720 | class = look_up_lock_class(lock, subclass); | |
721 | if (likely(class)) | |
87cdee71 | 722 | goto out_set_class_cache; |
8e18257d PZ |
723 | |
724 | /* | |
725 | * Debug-check: all keys must be persistent! | |
726 | */ | |
727 | if (!static_obj(lock->key)) { | |
728 | debug_locks_off(); | |
729 | printk("INFO: trying to register non-static key.\n"); | |
730 | printk("the code is fine but needs lockdep annotation.\n"); | |
731 | printk("turning off the locking correctness validator.\n"); | |
732 | dump_stack(); | |
733 | ||
734 | return NULL; | |
735 | } | |
736 | ||
737 | key = lock->key->subkeys + subclass; | |
738 | hash_head = classhashentry(key); | |
739 | ||
8e18257d | 740 | if (!graph_lock()) { |
8e18257d PZ |
741 | return NULL; |
742 | } | |
743 | /* | |
744 | * We have to do the hash-walk again, to avoid races | |
745 | * with another CPU: | |
746 | */ | |
a63f38cc | 747 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
748 | if (class->key == key) |
749 | goto out_unlock_set; | |
35a9393c PZ |
750 | } |
751 | ||
8e18257d PZ |
752 | /* |
753 | * Allocate a new key from the static array, and add it to | |
754 | * the hash: | |
755 | */ | |
756 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
757 | if (!debug_locks_off_graph_unlock()) { | |
8e18257d PZ |
758 | return NULL; |
759 | } | |
8e18257d | 760 | |
2c522836 | 761 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 762 | dump_stack(); |
8e18257d PZ |
763 | return NULL; |
764 | } | |
765 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 766 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
767 | class->key = key; |
768 | class->name = lock->name; | |
769 | class->subclass = subclass; | |
770 | INIT_LIST_HEAD(&class->lock_entry); | |
771 | INIT_LIST_HEAD(&class->locks_before); | |
772 | INIT_LIST_HEAD(&class->locks_after); | |
773 | class->name_version = count_matching_names(class); | |
774 | /* | |
775 | * We use RCU's safe list-add method to make | |
776 | * parallel walking of the hash-list safe: | |
777 | */ | |
a63f38cc | 778 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
1481197b DF |
779 | /* |
780 | * Add it to the global list of classes: | |
781 | */ | |
782 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
783 | |
784 | if (verbose(class)) { | |
785 | graph_unlock(); | |
8e18257d PZ |
786 | |
787 | printk("\nnew class %p: %s", class->key, class->name); | |
788 | if (class->name_version > 1) | |
789 | printk("#%d", class->name_version); | |
790 | printk("\n"); | |
791 | dump_stack(); | |
792 | ||
8e18257d | 793 | if (!graph_lock()) { |
8e18257d PZ |
794 | return NULL; |
795 | } | |
796 | } | |
797 | out_unlock_set: | |
798 | graph_unlock(); | |
8e18257d | 799 | |
87cdee71 | 800 | out_set_class_cache: |
8e18257d | 801 | if (!subclass || force) |
62016250 HM |
802 | lock->class_cache[0] = class; |
803 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
804 | lock->class_cache[subclass] = class; | |
8e18257d | 805 | |
0119fee4 PZ |
806 | /* |
807 | * Hash collision, did we smoke some? We found a class with a matching | |
808 | * hash but the subclass -- which is hashed in -- didn't match. | |
809 | */ | |
8e18257d PZ |
810 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
811 | return NULL; | |
812 | ||
813 | return class; | |
814 | } | |
815 | ||
816 | #ifdef CONFIG_PROVE_LOCKING | |
817 | /* | |
818 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
819 | * with NULL on failure) | |
820 | */ | |
821 | static struct lock_list *alloc_list_entry(void) | |
822 | { | |
823 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
824 | if (!debug_locks_off_graph_unlock()) | |
825 | return NULL; | |
826 | ||
2c522836 | 827 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 828 | dump_stack(); |
8e18257d PZ |
829 | return NULL; |
830 | } | |
831 | return list_entries + nr_list_entries++; | |
832 | } | |
833 | ||
834 | /* | |
835 | * Add a new dependency to the head of the list: | |
836 | */ | |
837 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
4726f2a6 YZ |
838 | struct list_head *head, unsigned long ip, |
839 | int distance, struct stack_trace *trace) | |
8e18257d PZ |
840 | { |
841 | struct lock_list *entry; | |
842 | /* | |
843 | * Lock not present yet - get a new dependency struct and | |
844 | * add it to the list: | |
845 | */ | |
846 | entry = alloc_list_entry(); | |
847 | if (!entry) | |
848 | return 0; | |
849 | ||
74870172 ZY |
850 | entry->class = this; |
851 | entry->distance = distance; | |
4726f2a6 | 852 | entry->trace = *trace; |
8e18257d | 853 | /* |
35a9393c PZ |
854 | * Both allocation and removal are done under the graph lock; but |
855 | * iteration is under RCU-sched; see look_up_lock_class() and | |
856 | * lockdep_free_key_range(). | |
8e18257d PZ |
857 | */ |
858 | list_add_tail_rcu(&entry->entry, head); | |
859 | ||
860 | return 1; | |
861 | } | |
862 | ||
98c33edd PZ |
863 | /* |
864 | * For good efficiency of modular, we use power of 2 | |
865 | */ | |
af012961 PZ |
866 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
867 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
868 | ||
98c33edd PZ |
869 | /* |
870 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
871 | * breadth-first search(BFS)algorithem, by which we can build |
872 | * the shortest path from the next lock to be acquired to the | |
873 | * previous held lock if there is a circular between them. | |
98c33edd | 874 | */ |
af012961 PZ |
875 | struct circular_queue { |
876 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
877 | unsigned int front, rear; | |
878 | }; | |
879 | ||
880 | static struct circular_queue lock_cq; | |
af012961 | 881 | |
12f3dfd0 | 882 | unsigned int max_bfs_queue_depth; |
af012961 | 883 | |
e351b660 ML |
884 | static unsigned int lockdep_dependency_gen_id; |
885 | ||
af012961 PZ |
886 | static inline void __cq_init(struct circular_queue *cq) |
887 | { | |
888 | cq->front = cq->rear = 0; | |
e351b660 | 889 | lockdep_dependency_gen_id++; |
af012961 PZ |
890 | } |
891 | ||
892 | static inline int __cq_empty(struct circular_queue *cq) | |
893 | { | |
894 | return (cq->front == cq->rear); | |
895 | } | |
896 | ||
897 | static inline int __cq_full(struct circular_queue *cq) | |
898 | { | |
899 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
900 | } | |
901 | ||
902 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
903 | { | |
904 | if (__cq_full(cq)) | |
905 | return -1; | |
906 | ||
907 | cq->element[cq->rear] = elem; | |
908 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
909 | return 0; | |
910 | } | |
911 | ||
912 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
913 | { | |
914 | if (__cq_empty(cq)) | |
915 | return -1; | |
916 | ||
917 | *elem = cq->element[cq->front]; | |
918 | cq->front = (cq->front + 1) & CQ_MASK; | |
919 | return 0; | |
920 | } | |
921 | ||
922 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
923 | { | |
924 | return (cq->rear - cq->front) & CQ_MASK; | |
925 | } | |
926 | ||
927 | static inline void mark_lock_accessed(struct lock_list *lock, | |
928 | struct lock_list *parent) | |
929 | { | |
930 | unsigned long nr; | |
98c33edd | 931 | |
af012961 | 932 | nr = lock - list_entries; |
0119fee4 | 933 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 934 | lock->parent = parent; |
e351b660 | 935 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
936 | } |
937 | ||
938 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
939 | { | |
940 | unsigned long nr; | |
98c33edd | 941 | |
af012961 | 942 | nr = lock - list_entries; |
0119fee4 | 943 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 944 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
945 | } |
946 | ||
947 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
948 | { | |
949 | return child->parent; | |
950 | } | |
951 | ||
952 | static inline int get_lock_depth(struct lock_list *child) | |
953 | { | |
954 | int depth = 0; | |
955 | struct lock_list *parent; | |
956 | ||
957 | while ((parent = get_lock_parent(child))) { | |
958 | child = parent; | |
959 | depth++; | |
960 | } | |
961 | return depth; | |
962 | } | |
963 | ||
9e2d551e | 964 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
965 | void *data, |
966 | int (*match)(struct lock_list *entry, void *data), | |
967 | struct lock_list **target_entry, | |
968 | int forward) | |
c94aa5ca ML |
969 | { |
970 | struct lock_list *entry; | |
d588e461 | 971 | struct list_head *head; |
c94aa5ca ML |
972 | struct circular_queue *cq = &lock_cq; |
973 | int ret = 1; | |
974 | ||
9e2d551e | 975 | if (match(source_entry, data)) { |
c94aa5ca ML |
976 | *target_entry = source_entry; |
977 | ret = 0; | |
978 | goto exit; | |
979 | } | |
980 | ||
d588e461 ML |
981 | if (forward) |
982 | head = &source_entry->class->locks_after; | |
983 | else | |
984 | head = &source_entry->class->locks_before; | |
985 | ||
986 | if (list_empty(head)) | |
987 | goto exit; | |
988 | ||
989 | __cq_init(cq); | |
c94aa5ca ML |
990 | __cq_enqueue(cq, (unsigned long)source_entry); |
991 | ||
992 | while (!__cq_empty(cq)) { | |
993 | struct lock_list *lock; | |
c94aa5ca ML |
994 | |
995 | __cq_dequeue(cq, (unsigned long *)&lock); | |
996 | ||
997 | if (!lock->class) { | |
998 | ret = -2; | |
999 | goto exit; | |
1000 | } | |
1001 | ||
1002 | if (forward) | |
1003 | head = &lock->class->locks_after; | |
1004 | else | |
1005 | head = &lock->class->locks_before; | |
1006 | ||
35a9393c PZ |
1007 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1008 | ||
1009 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1010 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1011 | unsigned int cq_depth; |
c94aa5ca | 1012 | mark_lock_accessed(entry, lock); |
9e2d551e | 1013 | if (match(entry, data)) { |
c94aa5ca ML |
1014 | *target_entry = entry; |
1015 | ret = 0; | |
1016 | goto exit; | |
1017 | } | |
1018 | ||
1019 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1020 | ret = -1; | |
1021 | goto exit; | |
1022 | } | |
12f3dfd0 ML |
1023 | cq_depth = __cq_get_elem_count(cq); |
1024 | if (max_bfs_queue_depth < cq_depth) | |
1025 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1026 | } |
1027 | } | |
1028 | } | |
1029 | exit: | |
1030 | return ret; | |
1031 | } | |
1032 | ||
d7aaba14 | 1033 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1034 | void *data, |
1035 | int (*match)(struct lock_list *entry, void *data), | |
1036 | struct lock_list **target_entry) | |
c94aa5ca | 1037 | { |
9e2d551e | 1038 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1039 | |
1040 | } | |
1041 | ||
d7aaba14 | 1042 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1043 | void *data, |
1044 | int (*match)(struct lock_list *entry, void *data), | |
1045 | struct lock_list **target_entry) | |
c94aa5ca | 1046 | { |
9e2d551e | 1047 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1048 | |
1049 | } | |
1050 | ||
8e18257d PZ |
1051 | /* |
1052 | * Recursive, forwards-direction lock-dependency checking, used for | |
1053 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1054 | * checking. | |
8e18257d | 1055 | */ |
8e18257d PZ |
1056 | |
1057 | /* | |
1058 | * Print a dependency chain entry (this is only done when a deadlock | |
1059 | * has been detected): | |
1060 | */ | |
1061 | static noinline int | |
24208ca7 | 1062 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1063 | { |
1064 | if (debug_locks_silent) | |
1065 | return 0; | |
1066 | printk("\n-> #%u", depth); | |
1067 | print_lock_name(target->class); | |
1068 | printk(":\n"); | |
1069 | print_stack_trace(&target->trace, 6); | |
1070 | ||
1071 | return 0; | |
1072 | } | |
1073 | ||
f4185812 SR |
1074 | static void |
1075 | print_circular_lock_scenario(struct held_lock *src, | |
1076 | struct held_lock *tgt, | |
1077 | struct lock_list *prt) | |
1078 | { | |
1079 | struct lock_class *source = hlock_class(src); | |
1080 | struct lock_class *target = hlock_class(tgt); | |
1081 | struct lock_class *parent = prt->class; | |
1082 | ||
1083 | /* | |
1084 | * A direct locking problem where unsafe_class lock is taken | |
1085 | * directly by safe_class lock, then all we need to show | |
1086 | * is the deadlock scenario, as it is obvious that the | |
1087 | * unsafe lock is taken under the safe lock. | |
1088 | * | |
1089 | * But if there is a chain instead, where the safe lock takes | |
1090 | * an intermediate lock (middle_class) where this lock is | |
1091 | * not the same as the safe lock, then the lock chain is | |
1092 | * used to describe the problem. Otherwise we would need | |
1093 | * to show a different CPU case for each link in the chain | |
1094 | * from the safe_class lock to the unsafe_class lock. | |
1095 | */ | |
1096 | if (parent != source) { | |
1097 | printk("Chain exists of:\n "); | |
1098 | __print_lock_name(source); | |
1099 | printk(" --> "); | |
1100 | __print_lock_name(parent); | |
1101 | printk(" --> "); | |
1102 | __print_lock_name(target); | |
1103 | printk("\n\n"); | |
1104 | } | |
1105 | ||
1106 | printk(" Possible unsafe locking scenario:\n\n"); | |
1107 | printk(" CPU0 CPU1\n"); | |
1108 | printk(" ---- ----\n"); | |
1109 | printk(" lock("); | |
1110 | __print_lock_name(target); | |
1111 | printk(");\n"); | |
1112 | printk(" lock("); | |
1113 | __print_lock_name(parent); | |
1114 | printk(");\n"); | |
1115 | printk(" lock("); | |
1116 | __print_lock_name(target); | |
1117 | printk(");\n"); | |
1118 | printk(" lock("); | |
1119 | __print_lock_name(source); | |
1120 | printk(");\n"); | |
1121 | printk("\n *** DEADLOCK ***\n\n"); | |
1122 | } | |
1123 | ||
8e18257d PZ |
1124 | /* |
1125 | * When a circular dependency is detected, print the | |
1126 | * header first: | |
1127 | */ | |
1128 | static noinline int | |
db0002a3 ML |
1129 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1130 | struct held_lock *check_src, | |
1131 | struct held_lock *check_tgt) | |
8e18257d PZ |
1132 | { |
1133 | struct task_struct *curr = current; | |
1134 | ||
c94aa5ca | 1135 | if (debug_locks_silent) |
8e18257d PZ |
1136 | return 0; |
1137 | ||
b3fbab05 PM |
1138 | printk("\n"); |
1139 | printk("======================================================\n"); | |
1140 | printk("[ INFO: possible circular locking dependency detected ]\n"); | |
fbdc4b9a | 1141 | print_kernel_ident(); |
b3fbab05 | 1142 | printk("-------------------------------------------------------\n"); |
8e18257d | 1143 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1144 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1145 | print_lock(check_src); |
8e18257d | 1146 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1147 | print_lock(check_tgt); |
8e18257d PZ |
1148 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1149 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1150 | ||
1151 | print_circular_bug_entry(entry, depth); | |
1152 | ||
1153 | return 0; | |
1154 | } | |
1155 | ||
9e2d551e ML |
1156 | static inline int class_equal(struct lock_list *entry, void *data) |
1157 | { | |
1158 | return entry->class == data; | |
1159 | } | |
1160 | ||
db0002a3 ML |
1161 | static noinline int print_circular_bug(struct lock_list *this, |
1162 | struct lock_list *target, | |
1163 | struct held_lock *check_src, | |
1164 | struct held_lock *check_tgt) | |
8e18257d PZ |
1165 | { |
1166 | struct task_struct *curr = current; | |
c94aa5ca | 1167 | struct lock_list *parent; |
f4185812 | 1168 | struct lock_list *first_parent; |
24208ca7 | 1169 | int depth; |
8e18257d | 1170 | |
c94aa5ca | 1171 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1172 | return 0; |
1173 | ||
db0002a3 | 1174 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1175 | return 0; |
1176 | ||
c94aa5ca ML |
1177 | depth = get_lock_depth(target); |
1178 | ||
db0002a3 | 1179 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1180 | |
1181 | parent = get_lock_parent(target); | |
f4185812 | 1182 | first_parent = parent; |
c94aa5ca ML |
1183 | |
1184 | while (parent) { | |
1185 | print_circular_bug_entry(parent, --depth); | |
1186 | parent = get_lock_parent(parent); | |
1187 | } | |
8e18257d PZ |
1188 | |
1189 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1190 | print_circular_lock_scenario(check_src, check_tgt, |
1191 | first_parent); | |
1192 | ||
8e18257d PZ |
1193 | lockdep_print_held_locks(curr); |
1194 | ||
1195 | printk("\nstack backtrace:\n"); | |
1196 | dump_stack(); | |
1197 | ||
1198 | return 0; | |
1199 | } | |
1200 | ||
db0002a3 ML |
1201 | static noinline int print_bfs_bug(int ret) |
1202 | { | |
1203 | if (!debug_locks_off_graph_unlock()) | |
1204 | return 0; | |
1205 | ||
0119fee4 PZ |
1206 | /* |
1207 | * Breadth-first-search failed, graph got corrupted? | |
1208 | */ | |
db0002a3 ML |
1209 | WARN(1, "lockdep bfs error:%d\n", ret); |
1210 | ||
1211 | return 0; | |
1212 | } | |
1213 | ||
ef681026 | 1214 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1215 | { |
ef681026 ML |
1216 | (*(unsigned long *)data)++; |
1217 | return 0; | |
1218 | } | |
419ca3f1 | 1219 | |
5216d530 | 1220 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1221 | { |
1222 | unsigned long count = 0; | |
1223 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1224 | |
ef681026 | 1225 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1226 | |
ef681026 | 1227 | return count; |
419ca3f1 | 1228 | } |
419ca3f1 DM |
1229 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1230 | { | |
1231 | unsigned long ret, flags; | |
ef681026 ML |
1232 | struct lock_list this; |
1233 | ||
1234 | this.parent = NULL; | |
1235 | this.class = class; | |
419ca3f1 DM |
1236 | |
1237 | local_irq_save(flags); | |
0199c4e6 | 1238 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1239 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1240 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1241 | local_irq_restore(flags); |
1242 | ||
1243 | return ret; | |
1244 | } | |
1245 | ||
5216d530 | 1246 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1247 | { |
ef681026 ML |
1248 | unsigned long count = 0; |
1249 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1250 | |
ef681026 | 1251 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1252 | |
ef681026 | 1253 | return count; |
419ca3f1 DM |
1254 | } |
1255 | ||
1256 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1257 | { | |
1258 | unsigned long ret, flags; | |
ef681026 ML |
1259 | struct lock_list this; |
1260 | ||
1261 | this.parent = NULL; | |
1262 | this.class = class; | |
419ca3f1 DM |
1263 | |
1264 | local_irq_save(flags); | |
0199c4e6 | 1265 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1266 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1267 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1268 | local_irq_restore(flags); |
1269 | ||
1270 | return ret; | |
1271 | } | |
1272 | ||
8e18257d PZ |
1273 | /* |
1274 | * Prove that the dependency graph starting at <entry> can not | |
1275 | * lead to <target>. Print an error and return 0 if it does. | |
1276 | */ | |
1277 | static noinline int | |
db0002a3 ML |
1278 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1279 | struct lock_list **target_entry) | |
8e18257d | 1280 | { |
db0002a3 | 1281 | int result; |
8e18257d | 1282 | |
bd6d29c2 | 1283 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1284 | |
d7aaba14 | 1285 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1286 | |
db0002a3 ML |
1287 | return result; |
1288 | } | |
c94aa5ca | 1289 | |
81d68a96 | 1290 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1291 | /* |
1292 | * Forwards and backwards subgraph searching, for the purposes of | |
1293 | * proving that two subgraphs can be connected by a new dependency | |
1294 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1295 | */ | |
fbb9ce95 | 1296 | |
d7aaba14 ML |
1297 | static inline int usage_match(struct lock_list *entry, void *bit) |
1298 | { | |
1299 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1300 | } | |
1301 | ||
1302 | ||
1303 | ||
fbb9ce95 IM |
1304 | /* |
1305 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1306 | * at @root->class that matches @bit. |
fbb9ce95 | 1307 | * |
d7aaba14 ML |
1308 | * Return 0 if such a node exists in the subgraph, and put that node |
1309 | * into *@target_entry. | |
fbb9ce95 | 1310 | * |
d7aaba14 ML |
1311 | * Return 1 otherwise and keep *@target_entry unchanged. |
1312 | * Return <0 on error. | |
fbb9ce95 | 1313 | */ |
d7aaba14 ML |
1314 | static int |
1315 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1316 | struct lock_list **target_entry) | |
fbb9ce95 | 1317 | { |
d7aaba14 | 1318 | int result; |
fbb9ce95 | 1319 | |
bd6d29c2 | 1320 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1321 | |
d7aaba14 ML |
1322 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1323 | ||
1324 | return result; | |
fbb9ce95 IM |
1325 | } |
1326 | ||
1327 | /* | |
1328 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1329 | * at @root->class that matches @bit. |
fbb9ce95 | 1330 | * |
d7aaba14 ML |
1331 | * Return 0 if such a node exists in the subgraph, and put that node |
1332 | * into *@target_entry. | |
fbb9ce95 | 1333 | * |
d7aaba14 ML |
1334 | * Return 1 otherwise and keep *@target_entry unchanged. |
1335 | * Return <0 on error. | |
fbb9ce95 | 1336 | */ |
d7aaba14 ML |
1337 | static int |
1338 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1339 | struct lock_list **target_entry) | |
fbb9ce95 | 1340 | { |
d7aaba14 | 1341 | int result; |
fbb9ce95 | 1342 | |
bd6d29c2 | 1343 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1344 | |
d7aaba14 | 1345 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1346 | |
d7aaba14 | 1347 | return result; |
fbb9ce95 IM |
1348 | } |
1349 | ||
af012961 PZ |
1350 | static void print_lock_class_header(struct lock_class *class, int depth) |
1351 | { | |
1352 | int bit; | |
1353 | ||
1354 | printk("%*s->", depth, ""); | |
1355 | print_lock_name(class); | |
1356 | printk(" ops: %lu", class->ops); | |
1357 | printk(" {\n"); | |
1358 | ||
1359 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1360 | if (class->usage_mask & (1 << bit)) { | |
1361 | int len = depth; | |
1362 | ||
1363 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1364 | len += printk(" at:\n"); | |
1365 | print_stack_trace(class->usage_traces + bit, len); | |
1366 | } | |
1367 | } | |
1368 | printk("%*s }\n", depth, ""); | |
1369 | ||
1370 | printk("%*s ... key at: ",depth,""); | |
1371 | print_ip_sym((unsigned long)class->key); | |
1372 | } | |
1373 | ||
1374 | /* | |
1375 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1376 | */ | |
1377 | static void __used | |
1378 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1379 | struct lock_list *root) | |
1380 | { | |
1381 | struct lock_list *entry = leaf; | |
1382 | int depth; | |
1383 | ||
1384 | /*compute depth from generated tree by BFS*/ | |
1385 | depth = get_lock_depth(leaf); | |
1386 | ||
1387 | do { | |
1388 | print_lock_class_header(entry->class, depth); | |
1389 | printk("%*s ... acquired at:\n", depth, ""); | |
1390 | print_stack_trace(&entry->trace, 2); | |
1391 | printk("\n"); | |
1392 | ||
1393 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1394 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1395 | break; |
1396 | } | |
1397 | ||
1398 | entry = get_lock_parent(entry); | |
1399 | depth--; | |
1400 | } while (entry && (depth >= 0)); | |
1401 | ||
1402 | return; | |
1403 | } | |
d7aaba14 | 1404 | |
3003eba3 SR |
1405 | static void |
1406 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1407 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1408 | struct lock_class *prev_class, |
1409 | struct lock_class *next_class) | |
3003eba3 SR |
1410 | { |
1411 | struct lock_class *safe_class = safe_entry->class; | |
1412 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1413 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1414 | |
1415 | if (middle_class == safe_class) | |
dad3d743 | 1416 | middle_class = next_class; |
3003eba3 SR |
1417 | |
1418 | /* | |
1419 | * A direct locking problem where unsafe_class lock is taken | |
1420 | * directly by safe_class lock, then all we need to show | |
1421 | * is the deadlock scenario, as it is obvious that the | |
1422 | * unsafe lock is taken under the safe lock. | |
1423 | * | |
1424 | * But if there is a chain instead, where the safe lock takes | |
1425 | * an intermediate lock (middle_class) where this lock is | |
1426 | * not the same as the safe lock, then the lock chain is | |
1427 | * used to describe the problem. Otherwise we would need | |
1428 | * to show a different CPU case for each link in the chain | |
1429 | * from the safe_class lock to the unsafe_class lock. | |
1430 | */ | |
1431 | if (middle_class != unsafe_class) { | |
1432 | printk("Chain exists of:\n "); | |
1433 | __print_lock_name(safe_class); | |
1434 | printk(" --> "); | |
1435 | __print_lock_name(middle_class); | |
1436 | printk(" --> "); | |
1437 | __print_lock_name(unsafe_class); | |
1438 | printk("\n\n"); | |
1439 | } | |
1440 | ||
1441 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1442 | printk(" CPU0 CPU1\n"); | |
1443 | printk(" ---- ----\n"); | |
1444 | printk(" lock("); | |
1445 | __print_lock_name(unsafe_class); | |
1446 | printk(");\n"); | |
1447 | printk(" local_irq_disable();\n"); | |
1448 | printk(" lock("); | |
1449 | __print_lock_name(safe_class); | |
1450 | printk(");\n"); | |
1451 | printk(" lock("); | |
1452 | __print_lock_name(middle_class); | |
1453 | printk(");\n"); | |
1454 | printk(" <Interrupt>\n"); | |
1455 | printk(" lock("); | |
1456 | __print_lock_name(safe_class); | |
1457 | printk(");\n"); | |
1458 | printk("\n *** DEADLOCK ***\n\n"); | |
1459 | } | |
1460 | ||
fbb9ce95 IM |
1461 | static int |
1462 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1463 | struct lock_list *prev_root, |
1464 | struct lock_list *next_root, | |
1465 | struct lock_list *backwards_entry, | |
1466 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1467 | struct held_lock *prev, |
1468 | struct held_lock *next, | |
1469 | enum lock_usage_bit bit1, | |
1470 | enum lock_usage_bit bit2, | |
1471 | const char *irqclass) | |
1472 | { | |
74c383f1 | 1473 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1474 | return 0; |
1475 | ||
b3fbab05 PM |
1476 | printk("\n"); |
1477 | printk("======================================================\n"); | |
1478 | printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
fbb9ce95 | 1479 | irqclass, irqclass); |
fbdc4b9a | 1480 | print_kernel_ident(); |
b3fbab05 | 1481 | printk("------------------------------------------------------\n"); |
fbb9ce95 | 1482 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1483 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1484 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1485 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1486 | curr->hardirqs_enabled, | |
1487 | curr->softirqs_enabled); | |
1488 | print_lock(next); | |
1489 | ||
1490 | printk("\nand this task is already holding:\n"); | |
1491 | print_lock(prev); | |
1492 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1493 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1494 | printk(" ->"); |
f82b217e | 1495 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1496 | printk("\n"); |
1497 | ||
1498 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1499 | irqclass); | |
24208ca7 | 1500 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1501 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1502 | ||
24208ca7 | 1503 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1504 | |
1505 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1506 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1507 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1508 | printk("..."); | |
1509 | ||
24208ca7 | 1510 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1511 | |
1512 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1513 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1514 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1515 | |
fbb9ce95 IM |
1516 | lockdep_print_held_locks(curr); |
1517 | ||
24208ca7 ML |
1518 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1519 | printk(" and the holding lock:\n"); | |
1520 | if (!save_trace(&prev_root->trace)) | |
1521 | return 0; | |
1522 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1523 | |
24208ca7 ML |
1524 | printk("\nthe dependencies between the lock to be acquired"); |
1525 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1526 | if (!save_trace(&next_root->trace)) | |
1527 | return 0; | |
1528 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1529 | |
1530 | printk("\nstack backtrace:\n"); | |
1531 | dump_stack(); | |
1532 | ||
1533 | return 0; | |
1534 | } | |
1535 | ||
1536 | static int | |
1537 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1538 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1539 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1540 | { | |
1541 | int ret; | |
24208ca7 | 1542 | struct lock_list this, that; |
d7aaba14 | 1543 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1544 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1545 | |
1546 | this.parent = NULL; | |
1547 | ||
1548 | this.class = hlock_class(prev); | |
1549 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1550 | if (ret < 0) |
1551 | return print_bfs_bug(ret); | |
1552 | if (ret == 1) | |
1553 | return ret; | |
d7aaba14 | 1554 | |
24208ca7 ML |
1555 | that.parent = NULL; |
1556 | that.class = hlock_class(next); | |
1557 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1558 | if (ret < 0) |
1559 | return print_bfs_bug(ret); | |
1560 | if (ret == 1) | |
1561 | return ret; | |
fbb9ce95 | 1562 | |
24208ca7 ML |
1563 | return print_bad_irq_dependency(curr, &this, &that, |
1564 | target_entry, target_entry1, | |
1565 | prev, next, | |
fbb9ce95 IM |
1566 | bit_backwards, bit_forwards, irqclass); |
1567 | } | |
1568 | ||
4f367d8a PZ |
1569 | static const char *state_names[] = { |
1570 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1571 | __stringify(__STATE), |
4f367d8a PZ |
1572 | #include "lockdep_states.h" |
1573 | #undef LOCKDEP_STATE | |
1574 | }; | |
1575 | ||
1576 | static const char *state_rnames[] = { | |
1577 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1578 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1579 | #include "lockdep_states.h" |
1580 | #undef LOCKDEP_STATE | |
1581 | }; | |
1582 | ||
1583 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1584 | { |
4f367d8a PZ |
1585 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1586 | } | |
8e18257d | 1587 | |
4f367d8a PZ |
1588 | static int exclusive_bit(int new_bit) |
1589 | { | |
8e18257d | 1590 | /* |
4f367d8a PZ |
1591 | * USED_IN |
1592 | * USED_IN_READ | |
1593 | * ENABLED | |
1594 | * ENABLED_READ | |
1595 | * | |
1596 | * bit 0 - write/read | |
1597 | * bit 1 - used_in/enabled | |
1598 | * bit 2+ state | |
8e18257d | 1599 | */ |
4f367d8a PZ |
1600 | |
1601 | int state = new_bit & ~3; | |
1602 | int dir = new_bit & 2; | |
8e18257d PZ |
1603 | |
1604 | /* | |
4f367d8a | 1605 | * keep state, bit flip the direction and strip read. |
8e18257d | 1606 | */ |
4f367d8a PZ |
1607 | return state | (dir ^ 2); |
1608 | } | |
1609 | ||
1610 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1611 | struct held_lock *next, enum lock_usage_bit bit) | |
1612 | { | |
8e18257d | 1613 | /* |
4f367d8a PZ |
1614 | * Prove that the new dependency does not connect a hardirq-safe |
1615 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1616 | * the backwards-subgraph starting at <prev>, and the |
1617 | * forwards-subgraph starting at <next>: | |
1618 | */ | |
4f367d8a PZ |
1619 | if (!check_usage(curr, prev, next, bit, |
1620 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1621 | return 0; |
1622 | ||
4f367d8a PZ |
1623 | bit++; /* _READ */ |
1624 | ||
cf40bd16 | 1625 | /* |
4f367d8a PZ |
1626 | * Prove that the new dependency does not connect a hardirq-safe-read |
1627 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1628 | * the backwards-subgraph starting at <prev>, and the |
1629 | * forwards-subgraph starting at <next>: | |
1630 | */ | |
4f367d8a PZ |
1631 | if (!check_usage(curr, prev, next, bit, |
1632 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1633 | return 0; |
1634 | ||
4f367d8a PZ |
1635 | return 1; |
1636 | } | |
1637 | ||
1638 | static int | |
1639 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1640 | struct held_lock *next) | |
1641 | { | |
1642 | #define LOCKDEP_STATE(__STATE) \ | |
1643 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1644 | return 0; |
4f367d8a PZ |
1645 | #include "lockdep_states.h" |
1646 | #undef LOCKDEP_STATE | |
cf40bd16 | 1647 | |
8e18257d PZ |
1648 | return 1; |
1649 | } | |
1650 | ||
1651 | static void inc_chains(void) | |
1652 | { | |
1653 | if (current->hardirq_context) | |
1654 | nr_hardirq_chains++; | |
1655 | else { | |
1656 | if (current->softirq_context) | |
1657 | nr_softirq_chains++; | |
1658 | else | |
1659 | nr_process_chains++; | |
1660 | } | |
1661 | } | |
1662 | ||
1663 | #else | |
1664 | ||
1665 | static inline int | |
1666 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1667 | struct held_lock *next) | |
1668 | { | |
1669 | return 1; | |
1670 | } | |
1671 | ||
1672 | static inline void inc_chains(void) | |
1673 | { | |
1674 | nr_process_chains++; | |
1675 | } | |
1676 | ||
fbb9ce95 IM |
1677 | #endif |
1678 | ||
48702ecf SR |
1679 | static void |
1680 | print_deadlock_scenario(struct held_lock *nxt, | |
1681 | struct held_lock *prv) | |
1682 | { | |
1683 | struct lock_class *next = hlock_class(nxt); | |
1684 | struct lock_class *prev = hlock_class(prv); | |
1685 | ||
1686 | printk(" Possible unsafe locking scenario:\n\n"); | |
1687 | printk(" CPU0\n"); | |
1688 | printk(" ----\n"); | |
1689 | printk(" lock("); | |
1690 | __print_lock_name(prev); | |
1691 | printk(");\n"); | |
1692 | printk(" lock("); | |
1693 | __print_lock_name(next); | |
1694 | printk(");\n"); | |
1695 | printk("\n *** DEADLOCK ***\n\n"); | |
1696 | printk(" May be due to missing lock nesting notation\n\n"); | |
1697 | } | |
1698 | ||
fbb9ce95 IM |
1699 | static int |
1700 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1701 | struct held_lock *next) | |
1702 | { | |
74c383f1 | 1703 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1704 | return 0; |
1705 | ||
b3fbab05 PM |
1706 | printk("\n"); |
1707 | printk("=============================================\n"); | |
1708 | printk("[ INFO: possible recursive locking detected ]\n"); | |
fbdc4b9a | 1709 | print_kernel_ident(); |
b3fbab05 | 1710 | printk("---------------------------------------------\n"); |
fbb9ce95 | 1711 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1712 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1713 | print_lock(next); |
1714 | printk("\nbut task is already holding lock:\n"); | |
1715 | print_lock(prev); | |
1716 | ||
1717 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1718 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1719 | lockdep_print_held_locks(curr); |
1720 | ||
1721 | printk("\nstack backtrace:\n"); | |
1722 | dump_stack(); | |
1723 | ||
1724 | return 0; | |
1725 | } | |
1726 | ||
1727 | /* | |
1728 | * Check whether we are holding such a class already. | |
1729 | * | |
1730 | * (Note that this has to be done separately, because the graph cannot | |
1731 | * detect such classes of deadlocks.) | |
1732 | * | |
1733 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1734 | */ | |
1735 | static int | |
1736 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1737 | struct lockdep_map *next_instance, int read) | |
1738 | { | |
1739 | struct held_lock *prev; | |
7531e2f3 | 1740 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1741 | int i; |
1742 | ||
1743 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1744 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1745 | |
1746 | if (prev->instance == next->nest_lock) | |
1747 | nest = prev; | |
1748 | ||
f82b217e | 1749 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1750 | continue; |
7531e2f3 | 1751 | |
fbb9ce95 IM |
1752 | /* |
1753 | * Allow read-after-read recursion of the same | |
6c9076ec | 1754 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1755 | */ |
6c9076ec | 1756 | if ((read == 2) && prev->read) |
fbb9ce95 | 1757 | return 2; |
7531e2f3 PZ |
1758 | |
1759 | /* | |
1760 | * We're holding the nest_lock, which serializes this lock's | |
1761 | * nesting behaviour. | |
1762 | */ | |
1763 | if (nest) | |
1764 | return 2; | |
1765 | ||
fbb9ce95 IM |
1766 | return print_deadlock_bug(curr, prev, next); |
1767 | } | |
1768 | return 1; | |
1769 | } | |
1770 | ||
1771 | /* | |
1772 | * There was a chain-cache miss, and we are about to add a new dependency | |
1773 | * to a previous lock. We recursively validate the following rules: | |
1774 | * | |
1775 | * - would the adding of the <prev> -> <next> dependency create a | |
1776 | * circular dependency in the graph? [== circular deadlock] | |
1777 | * | |
1778 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1779 | * (in the full backwards-subgraph starting at <prev>) with any | |
1780 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1781 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1782 | * | |
1783 | * - does the new prev->next dependency connect any softirq-safe lock | |
1784 | * (in the full backwards-subgraph starting at <prev>) with any | |
1785 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1786 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1787 | * | |
1788 | * any of these scenarios could lead to a deadlock. | |
1789 | * | |
1790 | * Then if all the validations pass, we add the forwards and backwards | |
1791 | * dependency. | |
1792 | */ | |
1793 | static int | |
1794 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
8a5fd564 | 1795 | struct held_lock *next, int distance, int *stack_saved) |
fbb9ce95 IM |
1796 | { |
1797 | struct lock_list *entry; | |
1798 | int ret; | |
db0002a3 ML |
1799 | struct lock_list this; |
1800 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1801 | /* |
1802 | * Static variable, serialized by the graph_lock(). | |
1803 | * | |
1804 | * We use this static variable to save the stack trace in case | |
1805 | * we call into this function multiple times due to encountering | |
1806 | * trylocks in the held lock stack. | |
1807 | */ | |
1808 | static struct stack_trace trace; | |
fbb9ce95 IM |
1809 | |
1810 | /* | |
1811 | * Prove that the new <prev> -> <next> dependency would not | |
1812 | * create a circular dependency in the graph. (We do this by | |
1813 | * forward-recursing into the graph starting at <next>, and | |
1814 | * checking whether we can reach <prev>.) | |
1815 | * | |
1816 | * We are using global variables to control the recursion, to | |
1817 | * keep the stackframe size of the recursive functions low: | |
1818 | */ | |
db0002a3 ML |
1819 | this.class = hlock_class(next); |
1820 | this.parent = NULL; | |
1821 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1822 | if (unlikely(!ret)) | |
1823 | return print_circular_bug(&this, target_entry, next, prev); | |
1824 | else if (unlikely(ret < 0)) | |
1825 | return print_bfs_bug(ret); | |
c94aa5ca | 1826 | |
8e18257d | 1827 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1828 | return 0; |
1829 | ||
fbb9ce95 IM |
1830 | /* |
1831 | * For recursive read-locks we do all the dependency checks, | |
1832 | * but we dont store read-triggered dependencies (only | |
1833 | * write-triggered dependencies). This ensures that only the | |
1834 | * write-side dependencies matter, and that if for example a | |
1835 | * write-lock never takes any other locks, then the reads are | |
1836 | * equivalent to a NOP. | |
1837 | */ | |
1838 | if (next->read == 2 || prev->read == 2) | |
1839 | return 1; | |
1840 | /* | |
1841 | * Is the <prev> -> <next> dependency already present? | |
1842 | * | |
1843 | * (this may occur even though this is a new chain: consider | |
1844 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1845 | * chains - the second one will be new, but L1 already has | |
1846 | * L2 added to its dependency list, due to the first chain.) | |
1847 | */ | |
f82b217e DJ |
1848 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1849 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1850 | if (distance == 1) |
1851 | entry->distance = 1; | |
fbb9ce95 | 1852 | return 2; |
068135e6 | 1853 | } |
fbb9ce95 IM |
1854 | } |
1855 | ||
8a5fd564 DV |
1856 | if (!*stack_saved) { |
1857 | if (!save_trace(&trace)) | |
1858 | return 0; | |
1859 | *stack_saved = 1; | |
1860 | } | |
4726f2a6 | 1861 | |
fbb9ce95 IM |
1862 | /* |
1863 | * Ok, all validations passed, add the new lock | |
1864 | * to the previous lock's dependency list: | |
1865 | */ | |
f82b217e DJ |
1866 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1867 | &hlock_class(prev)->locks_after, | |
4726f2a6 | 1868 | next->acquire_ip, distance, &trace); |
068135e6 | 1869 | |
fbb9ce95 IM |
1870 | if (!ret) |
1871 | return 0; | |
910b1b2e | 1872 | |
f82b217e DJ |
1873 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1874 | &hlock_class(next)->locks_before, | |
4726f2a6 | 1875 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1876 | if (!ret) |
1877 | return 0; | |
fbb9ce95 IM |
1878 | |
1879 | /* | |
8e18257d PZ |
1880 | * Debugging printouts: |
1881 | */ | |
f82b217e | 1882 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8a5fd564 DV |
1883 | /* We drop graph lock, so another thread can overwrite trace. */ |
1884 | *stack_saved = 0; | |
8e18257d PZ |
1885 | graph_unlock(); |
1886 | printk("\n new dependency: "); | |
f82b217e | 1887 | print_lock_name(hlock_class(prev)); |
8e18257d | 1888 | printk(" => "); |
f82b217e | 1889 | print_lock_name(hlock_class(next)); |
8e18257d | 1890 | printk("\n"); |
fbb9ce95 | 1891 | dump_stack(); |
8e18257d | 1892 | return graph_lock(); |
fbb9ce95 | 1893 | } |
8e18257d PZ |
1894 | return 1; |
1895 | } | |
fbb9ce95 | 1896 | |
8e18257d PZ |
1897 | /* |
1898 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1899 | * The ones that are relevant are (in increasing distance from curr): | |
1900 | * all consecutive trylock entries and the final non-trylock entry - or | |
1901 | * the end of this context's lock-chain - whichever comes first. | |
1902 | */ | |
1903 | static int | |
1904 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1905 | { | |
1906 | int depth = curr->lockdep_depth; | |
8a5fd564 | 1907 | int stack_saved = 0; |
8e18257d | 1908 | struct held_lock *hlock; |
d6d897ce | 1909 | |
fbb9ce95 | 1910 | /* |
8e18257d PZ |
1911 | * Debugging checks. |
1912 | * | |
1913 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1914 | */ |
8e18257d PZ |
1915 | if (!depth) |
1916 | goto out_bug; | |
fbb9ce95 | 1917 | /* |
8e18257d PZ |
1918 | * At least two relevant locks must exist for this |
1919 | * to be a head: | |
fbb9ce95 | 1920 | */ |
8e18257d PZ |
1921 | if (curr->held_locks[depth].irq_context != |
1922 | curr->held_locks[depth-1].irq_context) | |
1923 | goto out_bug; | |
74c383f1 | 1924 | |
8e18257d PZ |
1925 | for (;;) { |
1926 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 1927 | hlock = curr->held_locks + depth - 1; |
8e18257d PZ |
1928 | /* |
1929 | * Only non-recursive-read entries get new dependencies | |
1930 | * added: | |
1931 | */ | |
1b5ff816 | 1932 | if (hlock->read != 2 && hlock->check) { |
4726f2a6 | 1933 | if (!check_prev_add(curr, hlock, next, |
8a5fd564 | 1934 | distance, &stack_saved)) |
8e18257d PZ |
1935 | return 0; |
1936 | /* | |
1937 | * Stop after the first non-trylock entry, | |
1938 | * as non-trylock entries have added their | |
1939 | * own direct dependencies already, so this | |
1940 | * lock is connected to them indirectly: | |
1941 | */ | |
1942 | if (!hlock->trylock) | |
1943 | break; | |
74c383f1 | 1944 | } |
8e18257d PZ |
1945 | depth--; |
1946 | /* | |
1947 | * End of lock-stack? | |
1948 | */ | |
1949 | if (!depth) | |
1950 | break; | |
1951 | /* | |
1952 | * Stop the search if we cross into another context: | |
1953 | */ | |
1954 | if (curr->held_locks[depth].irq_context != | |
1955 | curr->held_locks[depth-1].irq_context) | |
1956 | break; | |
fbb9ce95 | 1957 | } |
8e18257d PZ |
1958 | return 1; |
1959 | out_bug: | |
1960 | if (!debug_locks_off_graph_unlock()) | |
1961 | return 0; | |
fbb9ce95 | 1962 | |
0119fee4 PZ |
1963 | /* |
1964 | * Clearly we all shouldn't be here, but since we made it we | |
1965 | * can reliable say we messed up our state. See the above two | |
1966 | * gotos for reasons why we could possibly end up here. | |
1967 | */ | |
8e18257d | 1968 | WARN_ON(1); |
fbb9ce95 | 1969 | |
8e18257d | 1970 | return 0; |
fbb9ce95 IM |
1971 | } |
1972 | ||
8e18257d | 1973 | unsigned long nr_lock_chains; |
443cd507 | 1974 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1975 | int nr_chain_hlocks; |
443cd507 HY |
1976 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1977 | ||
1978 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1979 | { | |
1980 | return lock_classes + chain_hlocks[chain->base + i]; | |
1981 | } | |
8e18257d | 1982 | |
9e4e7554 IM |
1983 | /* |
1984 | * Returns the index of the first held_lock of the current chain | |
1985 | */ | |
1986 | static inline int get_first_held_lock(struct task_struct *curr, | |
1987 | struct held_lock *hlock) | |
1988 | { | |
1989 | int i; | |
1990 | struct held_lock *hlock_curr; | |
1991 | ||
1992 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1993 | hlock_curr = curr->held_locks + i; | |
1994 | if (hlock_curr->irq_context != hlock->irq_context) | |
1995 | break; | |
1996 | ||
1997 | } | |
1998 | ||
1999 | return ++i; | |
2000 | } | |
2001 | ||
2002 | /* | |
2003 | * Checks whether the chain and the current held locks are consistent | |
2004 | * in depth and also in content. If they are not it most likely means | |
2005 | * that there was a collision during the calculation of the chain_key. | |
2006 | * Returns: 0 not passed, 1 passed | |
2007 | */ | |
2008 | static int check_no_collision(struct task_struct *curr, | |
2009 | struct held_lock *hlock, | |
2010 | struct lock_chain *chain) | |
2011 | { | |
2012 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2013 | int i, j, id; | |
2014 | ||
2015 | i = get_first_held_lock(curr, hlock); | |
2016 | ||
2017 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) | |
2018 | return 0; | |
2019 | ||
2020 | for (j = 0; j < chain->depth - 1; j++, i++) { | |
2021 | id = curr->held_locks[i].class_idx - 1; | |
2022 | ||
2023 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) | |
2024 | return 0; | |
2025 | } | |
2026 | #endif | |
2027 | return 1; | |
2028 | } | |
2029 | ||
fbb9ce95 IM |
2030 | /* |
2031 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
2032 | * add it and return 1 - in this case the new dependency chain is |
2033 | * validated. If the key is already hashed, return 0. | |
2034 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 2035 | */ |
443cd507 HY |
2036 | static inline int lookup_chain_cache(struct task_struct *curr, |
2037 | struct held_lock *hlock, | |
2038 | u64 chain_key) | |
fbb9ce95 | 2039 | { |
f82b217e | 2040 | struct lock_class *class = hlock_class(hlock); |
a63f38cc | 2041 | struct hlist_head *hash_head = chainhashentry(chain_key); |
fbb9ce95 | 2042 | struct lock_chain *chain; |
e0944ee6 | 2043 | int i, j; |
fbb9ce95 | 2044 | |
0119fee4 PZ |
2045 | /* |
2046 | * We might need to take the graph lock, ensure we've got IRQs | |
2047 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2048 | * lockdep won't complain about its own locking errors. | |
2049 | */ | |
381a2292 JP |
2050 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2051 | return 0; | |
fbb9ce95 IM |
2052 | /* |
2053 | * We can walk it lock-free, because entries only get added | |
2054 | * to the hash: | |
2055 | */ | |
a63f38cc | 2056 | hlist_for_each_entry_rcu(chain, hash_head, entry) { |
fbb9ce95 IM |
2057 | if (chain->chain_key == chain_key) { |
2058 | cache_hit: | |
bd6d29c2 | 2059 | debug_atomic_inc(chain_lookup_hits); |
9e4e7554 IM |
2060 | if (!check_no_collision(curr, hlock, chain)) |
2061 | return 0; | |
2062 | ||
81fc685a | 2063 | if (very_verbose(class)) |
755cd900 AM |
2064 | printk("\nhash chain already cached, key: " |
2065 | "%016Lx tail class: [%p] %s\n", | |
2066 | (unsigned long long)chain_key, | |
2067 | class->key, class->name); | |
fbb9ce95 IM |
2068 | return 0; |
2069 | } | |
2070 | } | |
81fc685a | 2071 | if (very_verbose(class)) |
755cd900 AM |
2072 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2073 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2074 | /* |
2075 | * Allocate a new chain entry from the static array, and add | |
2076 | * it to the hash: | |
2077 | */ | |
74c383f1 IM |
2078 | if (!graph_lock()) |
2079 | return 0; | |
fbb9ce95 IM |
2080 | /* |
2081 | * We have to walk the chain again locked - to avoid duplicates: | |
2082 | */ | |
a63f38cc | 2083 | hlist_for_each_entry(chain, hash_head, entry) { |
fbb9ce95 | 2084 | if (chain->chain_key == chain_key) { |
74c383f1 | 2085 | graph_unlock(); |
fbb9ce95 IM |
2086 | goto cache_hit; |
2087 | } | |
2088 | } | |
2089 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2090 | if (!debug_locks_off_graph_unlock()) |
2091 | return 0; | |
2092 | ||
2c522836 | 2093 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2094 | dump_stack(); |
fbb9ce95 IM |
2095 | return 0; |
2096 | } | |
2097 | chain = lock_chains + nr_lock_chains++; | |
2098 | chain->chain_key = chain_key; | |
443cd507 | 2099 | chain->irq_context = hlock->irq_context; |
9e4e7554 | 2100 | i = get_first_held_lock(curr, hlock); |
443cd507 | 2101 | chain->depth = curr->lockdep_depth + 1 - i; |
e0944ee6 SR |
2102 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2103 | chain->base = nr_chain_hlocks; | |
2104 | nr_chain_hlocks += chain->depth; | |
443cd507 | 2105 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2106 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2107 | chain_hlocks[chain->base + j] = lock_id; |
2108 | } | |
2109 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2110 | } | |
a63f38cc | 2111 | hlist_add_head_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2112 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2113 | inc_chains(); |
2114 | ||
2115 | return 1; | |
2116 | } | |
2117 | ||
2118 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2119 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2120 | { |
2121 | /* | |
2122 | * Trylock needs to maintain the stack of held locks, but it | |
2123 | * does not add new dependencies, because trylock can be done | |
2124 | * in any order. | |
2125 | * | |
2126 | * We look up the chain_key and do the O(N^2) check and update of | |
2127 | * the dependencies only if this is a new dependency chain. | |
2128 | * (If lookup_chain_cache() returns with 1 it acquires | |
2129 | * graph_lock for us) | |
2130 | */ | |
fb9edbe9 | 2131 | if (!hlock->trylock && hlock->check && |
443cd507 | 2132 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2133 | /* |
2134 | * Check whether last held lock: | |
2135 | * | |
2136 | * - is irq-safe, if this lock is irq-unsafe | |
2137 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2138 | * | |
2139 | * And check whether the new lock's dependency graph | |
2140 | * could lead back to the previous lock. | |
2141 | * | |
2142 | * any of these scenarios could lead to a deadlock. If | |
2143 | * All validations | |
2144 | */ | |
2145 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2146 | ||
2147 | if (!ret) | |
2148 | return 0; | |
2149 | /* | |
2150 | * Mark recursive read, as we jump over it when | |
2151 | * building dependencies (just like we jump over | |
2152 | * trylock entries): | |
2153 | */ | |
2154 | if (ret == 2) | |
2155 | hlock->read = 2; | |
2156 | /* | |
2157 | * Add dependency only if this lock is not the head | |
2158 | * of the chain, and if it's not a secondary read-lock: | |
2159 | */ | |
2160 | if (!chain_head && ret != 2) | |
2161 | if (!check_prevs_add(curr, hlock)) | |
2162 | return 0; | |
2163 | graph_unlock(); | |
2164 | } else | |
2165 | /* after lookup_chain_cache(): */ | |
2166 | if (unlikely(!debug_locks)) | |
2167 | return 0; | |
fbb9ce95 IM |
2168 | |
2169 | return 1; | |
2170 | } | |
8e18257d PZ |
2171 | #else |
2172 | static inline int validate_chain(struct task_struct *curr, | |
2173 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2174 | int chain_head, u64 chain_key) |
8e18257d PZ |
2175 | { |
2176 | return 1; | |
2177 | } | |
ca58abcb | 2178 | #endif |
fbb9ce95 IM |
2179 | |
2180 | /* | |
2181 | * We are building curr_chain_key incrementally, so double-check | |
2182 | * it from scratch, to make sure that it's done correctly: | |
2183 | */ | |
1d09daa5 | 2184 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2185 | { |
2186 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2187 | struct held_lock *hlock, *prev_hlock = NULL; | |
5f18ab5c | 2188 | unsigned int i; |
fbb9ce95 IM |
2189 | u64 chain_key = 0; |
2190 | ||
2191 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2192 | hlock = curr->held_locks + i; | |
2193 | if (chain_key != hlock->prev_chain_key) { | |
2194 | debug_locks_off(); | |
0119fee4 PZ |
2195 | /* |
2196 | * We got mighty confused, our chain keys don't match | |
2197 | * with what we expect, someone trample on our task state? | |
2198 | */ | |
2df8b1d6 | 2199 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2200 | curr->lockdep_depth, i, |
2201 | (unsigned long long)chain_key, | |
2202 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2203 | return; |
2204 | } | |
0119fee4 PZ |
2205 | /* |
2206 | * Whoops ran out of static storage again? | |
2207 | */ | |
5f18ab5c | 2208 | if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) |
381a2292 JP |
2209 | return; |
2210 | ||
fbb9ce95 IM |
2211 | if (prev_hlock && (prev_hlock->irq_context != |
2212 | hlock->irq_context)) | |
2213 | chain_key = 0; | |
5f18ab5c | 2214 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
fbb9ce95 IM |
2215 | prev_hlock = hlock; |
2216 | } | |
2217 | if (chain_key != curr->curr_chain_key) { | |
2218 | debug_locks_off(); | |
0119fee4 PZ |
2219 | /* |
2220 | * More smoking hash instead of calculating it, damn see these | |
2221 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2222 | */ | |
2df8b1d6 | 2223 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2224 | curr->lockdep_depth, i, |
2225 | (unsigned long long)chain_key, | |
2226 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2227 | } |
2228 | #endif | |
2229 | } | |
2230 | ||
282b5c2f SR |
2231 | static void |
2232 | print_usage_bug_scenario(struct held_lock *lock) | |
2233 | { | |
2234 | struct lock_class *class = hlock_class(lock); | |
2235 | ||
2236 | printk(" Possible unsafe locking scenario:\n\n"); | |
2237 | printk(" CPU0\n"); | |
2238 | printk(" ----\n"); | |
2239 | printk(" lock("); | |
2240 | __print_lock_name(class); | |
2241 | printk(");\n"); | |
2242 | printk(" <Interrupt>\n"); | |
2243 | printk(" lock("); | |
2244 | __print_lock_name(class); | |
2245 | printk(");\n"); | |
2246 | printk("\n *** DEADLOCK ***\n\n"); | |
2247 | } | |
2248 | ||
8e18257d PZ |
2249 | static int |
2250 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2251 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2252 | { | |
2253 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2254 | return 0; | |
2255 | ||
b3fbab05 PM |
2256 | printk("\n"); |
2257 | printk("=================================\n"); | |
2258 | printk("[ INFO: inconsistent lock state ]\n"); | |
fbdc4b9a | 2259 | print_kernel_ident(); |
b3fbab05 | 2260 | printk("---------------------------------\n"); |
8e18257d PZ |
2261 | |
2262 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2263 | usage_str[prev_bit], usage_str[new_bit]); | |
2264 | ||
2265 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2266 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2267 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2268 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2269 | trace_hardirqs_enabled(curr), | |
2270 | trace_softirqs_enabled(curr)); | |
2271 | print_lock(this); | |
2272 | ||
2273 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2274 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2275 | |
2276 | print_irqtrace_events(curr); | |
2277 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2278 | print_usage_bug_scenario(this); |
2279 | ||
8e18257d PZ |
2280 | lockdep_print_held_locks(curr); |
2281 | ||
2282 | printk("\nstack backtrace:\n"); | |
2283 | dump_stack(); | |
2284 | ||
2285 | return 0; | |
2286 | } | |
2287 | ||
2288 | /* | |
2289 | * Print out an error if an invalid bit is set: | |
2290 | */ | |
2291 | static inline int | |
2292 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2293 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2294 | { | |
f82b217e | 2295 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2296 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2297 | return 1; | |
2298 | } | |
2299 | ||
2300 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2301 | enum lock_usage_bit new_bit); | |
2302 | ||
81d68a96 | 2303 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2304 | |
2305 | /* | |
2306 | * print irq inversion bug: | |
2307 | */ | |
2308 | static int | |
24208ca7 ML |
2309 | print_irq_inversion_bug(struct task_struct *curr, |
2310 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2311 | struct held_lock *this, int forwards, |
2312 | const char *irqclass) | |
2313 | { | |
dad3d743 SR |
2314 | struct lock_list *entry = other; |
2315 | struct lock_list *middle = NULL; | |
2316 | int depth; | |
2317 | ||
74c383f1 | 2318 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2319 | return 0; |
2320 | ||
b3fbab05 PM |
2321 | printk("\n"); |
2322 | printk("=========================================================\n"); | |
2323 | printk("[ INFO: possible irq lock inversion dependency detected ]\n"); | |
fbdc4b9a | 2324 | print_kernel_ident(); |
b3fbab05 | 2325 | printk("---------------------------------------------------------\n"); |
fbb9ce95 | 2326 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2327 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2328 | print_lock(this); |
2329 | if (forwards) | |
26575e28 | 2330 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2331 | else |
26575e28 | 2332 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2333 | print_lock_name(other->class); |
fbb9ce95 IM |
2334 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2335 | ||
2336 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2337 | |
2338 | /* Find a middle lock (if one exists) */ | |
2339 | depth = get_lock_depth(other); | |
2340 | do { | |
2341 | if (depth == 0 && (entry != root)) { | |
2342 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2343 | break; | |
2344 | } | |
2345 | middle = entry; | |
2346 | entry = get_lock_parent(entry); | |
2347 | depth--; | |
2348 | } while (entry && entry != root && (depth >= 0)); | |
2349 | if (forwards) | |
2350 | print_irq_lock_scenario(root, other, | |
2351 | middle ? middle->class : root->class, other->class); | |
2352 | else | |
2353 | print_irq_lock_scenario(other, root, | |
2354 | middle ? middle->class : other->class, root->class); | |
2355 | ||
fbb9ce95 IM |
2356 | lockdep_print_held_locks(curr); |
2357 | ||
24208ca7 ML |
2358 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2359 | if (!save_trace(&root->trace)) | |
2360 | return 0; | |
2361 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2362 | |
2363 | printk("\nstack backtrace:\n"); | |
2364 | dump_stack(); | |
2365 | ||
2366 | return 0; | |
2367 | } | |
2368 | ||
2369 | /* | |
2370 | * Prove that in the forwards-direction subgraph starting at <this> | |
2371 | * there is no lock matching <mask>: | |
2372 | */ | |
2373 | static int | |
2374 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2375 | enum lock_usage_bit bit, const char *irqclass) | |
2376 | { | |
2377 | int ret; | |
d7aaba14 ML |
2378 | struct lock_list root; |
2379 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2380 | |
d7aaba14 ML |
2381 | root.parent = NULL; |
2382 | root.class = hlock_class(this); | |
2383 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2384 | if (ret < 0) |
2385 | return print_bfs_bug(ret); | |
2386 | if (ret == 1) | |
2387 | return ret; | |
fbb9ce95 | 2388 | |
24208ca7 | 2389 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2390 | this, 1, irqclass); |
fbb9ce95 IM |
2391 | } |
2392 | ||
2393 | /* | |
2394 | * Prove that in the backwards-direction subgraph starting at <this> | |
2395 | * there is no lock matching <mask>: | |
2396 | */ | |
2397 | static int | |
2398 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2399 | enum lock_usage_bit bit, const char *irqclass) | |
2400 | { | |
2401 | int ret; | |
d7aaba14 ML |
2402 | struct lock_list root; |
2403 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2404 | |
d7aaba14 ML |
2405 | root.parent = NULL; |
2406 | root.class = hlock_class(this); | |
2407 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2408 | if (ret < 0) |
2409 | return print_bfs_bug(ret); | |
2410 | if (ret == 1) | |
2411 | return ret; | |
fbb9ce95 | 2412 | |
24208ca7 | 2413 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2414 | this, 0, irqclass); |
fbb9ce95 IM |
2415 | } |
2416 | ||
3117df04 | 2417 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2418 | { |
2419 | printk("irq event stamp: %u\n", curr->irq_events); | |
2420 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2421 | print_ip_sym(curr->hardirq_enable_ip); | |
2422 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2423 | print_ip_sym(curr->hardirq_disable_ip); | |
2424 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2425 | print_ip_sym(curr->softirq_enable_ip); | |
2426 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2427 | print_ip_sym(curr->softirq_disable_ip); | |
2428 | } | |
2429 | ||
cd95302d | 2430 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2431 | { |
8e18257d PZ |
2432 | #if HARDIRQ_VERBOSE |
2433 | return class_filter(class); | |
2434 | #endif | |
fbb9ce95 IM |
2435 | return 0; |
2436 | } | |
2437 | ||
cd95302d | 2438 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2439 | { |
8e18257d PZ |
2440 | #if SOFTIRQ_VERBOSE |
2441 | return class_filter(class); | |
2442 | #endif | |
2443 | return 0; | |
fbb9ce95 IM |
2444 | } |
2445 | ||
cd95302d | 2446 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2447 | { |
2448 | #if RECLAIM_VERBOSE | |
2449 | return class_filter(class); | |
2450 | #endif | |
2451 | return 0; | |
2452 | } | |
2453 | ||
fbb9ce95 IM |
2454 | #define STRICT_READ_CHECKS 1 |
2455 | ||
cd95302d PZ |
2456 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2457 | #define LOCKDEP_STATE(__STATE) \ | |
2458 | __STATE##_verbose, | |
2459 | #include "lockdep_states.h" | |
2460 | #undef LOCKDEP_STATE | |
2461 | }; | |
2462 | ||
2463 | static inline int state_verbose(enum lock_usage_bit bit, | |
2464 | struct lock_class *class) | |
2465 | { | |
2466 | return state_verbose_f[bit >> 2](class); | |
2467 | } | |
2468 | ||
42c50d54 PZ |
2469 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2470 | enum lock_usage_bit bit, const char *name); | |
2471 | ||
6a6904d3 | 2472 | static int |
1c21f14e PZ |
2473 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2474 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2475 | { |
f989209e | 2476 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2477 | int read = new_bit & 1; |
42c50d54 PZ |
2478 | int dir = new_bit & 2; |
2479 | ||
38aa2714 PZ |
2480 | /* |
2481 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2482 | * has ENABLED state, which would allow recursion deadlocks. | |
2483 | * | |
2484 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2485 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2486 | */ | |
42c50d54 PZ |
2487 | check_usage_f usage = dir ? |
2488 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2489 | |
38aa2714 PZ |
2490 | /* |
2491 | * Validate that this particular lock does not have conflicting | |
2492 | * usage states. | |
2493 | */ | |
6a6904d3 PZ |
2494 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2495 | return 0; | |
42c50d54 | 2496 | |
38aa2714 PZ |
2497 | /* |
2498 | * Validate that the lock dependencies don't have conflicting usage | |
2499 | * states. | |
2500 | */ | |
2501 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2502 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2503 | return 0; |
780e820b | 2504 | |
38aa2714 PZ |
2505 | /* |
2506 | * Check for read in write conflicts | |
2507 | */ | |
2508 | if (!read) { | |
2509 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2510 | return 0; | |
2511 | ||
2512 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2513 | !usage(curr, this, excl_bit + 1, |
2514 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2515 | return 0; |
2516 | } | |
780e820b | 2517 | |
cd95302d | 2518 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2519 | return 2; |
2520 | ||
2521 | return 1; | |
2522 | } | |
2523 | ||
cf40bd16 | 2524 | enum mark_type { |
36bfb9bb PZ |
2525 | #define LOCKDEP_STATE(__STATE) __STATE, |
2526 | #include "lockdep_states.h" | |
2527 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2528 | }; |
2529 | ||
fbb9ce95 IM |
2530 | /* |
2531 | * Mark all held locks with a usage bit: | |
2532 | */ | |
1d09daa5 | 2533 | static int |
cf40bd16 | 2534 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2535 | { |
2536 | enum lock_usage_bit usage_bit; | |
2537 | struct held_lock *hlock; | |
2538 | int i; | |
2539 | ||
2540 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2541 | hlock = curr->held_locks + i; | |
2542 | ||
cf2ad4d1 PZ |
2543 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2544 | if (hlock->read) | |
2545 | usage_bit += 1; /* READ */ | |
2546 | ||
2547 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2548 | |
34d0ed5e | 2549 | if (!hlock->check) |
efbe2eee PZ |
2550 | continue; |
2551 | ||
4ff773bb | 2552 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2553 | return 0; |
2554 | } | |
2555 | ||
2556 | return 1; | |
2557 | } | |
2558 | ||
fbb9ce95 IM |
2559 | /* |
2560 | * Hardirqs will be enabled: | |
2561 | */ | |
dd4e5d3a | 2562 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2563 | { |
2564 | struct task_struct *curr = current; | |
fbb9ce95 | 2565 | |
fbb9ce95 IM |
2566 | /* we'll do an OFF -> ON transition: */ |
2567 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2568 | |
fbb9ce95 IM |
2569 | /* |
2570 | * We are going to turn hardirqs on, so set the | |
2571 | * usage bit for all held locks: | |
2572 | */ | |
cf40bd16 | 2573 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2574 | return; |
2575 | /* | |
2576 | * If we have softirqs enabled, then set the usage | |
2577 | * bit for all held locks. (disabled hardirqs prevented | |
2578 | * this bit from being set before) | |
2579 | */ | |
2580 | if (curr->softirqs_enabled) | |
cf40bd16 | 2581 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2582 | return; |
2583 | ||
8e18257d PZ |
2584 | curr->hardirq_enable_ip = ip; |
2585 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2586 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2587 | } |
dd4e5d3a | 2588 | |
b35f8305 | 2589 | __visible void trace_hardirqs_on_caller(unsigned long ip) |
dd4e5d3a PZ |
2590 | { |
2591 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2592 | ||
2593 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2594 | return; | |
2595 | ||
7d36b26b PZ |
2596 | if (unlikely(current->hardirqs_enabled)) { |
2597 | /* | |
2598 | * Neither irq nor preemption are disabled here | |
2599 | * so this is racy by nature but losing one hit | |
2600 | * in a stat is not a big deal. | |
2601 | */ | |
2602 | __debug_atomic_inc(redundant_hardirqs_on); | |
2603 | return; | |
2604 | } | |
2605 | ||
0119fee4 PZ |
2606 | /* |
2607 | * We're enabling irqs and according to our state above irqs weren't | |
2608 | * already enabled, yet we find the hardware thinks they are in fact | |
2609 | * enabled.. someone messed up their IRQ state tracing. | |
2610 | */ | |
dd4e5d3a PZ |
2611 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2612 | return; | |
2613 | ||
0119fee4 PZ |
2614 | /* |
2615 | * See the fine text that goes along with this variable definition. | |
2616 | */ | |
7d36b26b PZ |
2617 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2618 | return; | |
2619 | ||
0119fee4 PZ |
2620 | /* |
2621 | * Can't allow enabling interrupts while in an interrupt handler, | |
2622 | * that's general bad form and such. Recursion, limited stack etc.. | |
2623 | */ | |
7d36b26b PZ |
2624 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2625 | return; | |
2626 | ||
dd4e5d3a PZ |
2627 | current->lockdep_recursion = 1; |
2628 | __trace_hardirqs_on_caller(ip); | |
2629 | current->lockdep_recursion = 0; | |
2630 | } | |
81d68a96 | 2631 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2632 | |
1d09daa5 | 2633 | void trace_hardirqs_on(void) |
81d68a96 SR |
2634 | { |
2635 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2636 | } | |
8e18257d PZ |
2637 | EXPORT_SYMBOL(trace_hardirqs_on); |
2638 | ||
2639 | /* | |
2640 | * Hardirqs were disabled: | |
2641 | */ | |
b35f8305 | 2642 | __visible void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2643 | { |
2644 | struct task_struct *curr = current; | |
2645 | ||
6afe40b4 | 2646 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2647 | |
8e18257d PZ |
2648 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2649 | return; | |
2650 | ||
0119fee4 PZ |
2651 | /* |
2652 | * So we're supposed to get called after you mask local IRQs, but for | |
2653 | * some reason the hardware doesn't quite think you did a proper job. | |
2654 | */ | |
8e18257d PZ |
2655 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2656 | return; | |
2657 | ||
2658 | if (curr->hardirqs_enabled) { | |
2659 | /* | |
2660 | * We have done an ON -> OFF transition: | |
2661 | */ | |
2662 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2663 | curr->hardirq_disable_ip = ip; |
8e18257d | 2664 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2665 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2666 | } else |
bd6d29c2 | 2667 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2668 | } |
81d68a96 | 2669 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2670 | |
1d09daa5 | 2671 | void trace_hardirqs_off(void) |
81d68a96 SR |
2672 | { |
2673 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2674 | } | |
8e18257d PZ |
2675 | EXPORT_SYMBOL(trace_hardirqs_off); |
2676 | ||
2677 | /* | |
2678 | * Softirqs will be enabled: | |
2679 | */ | |
2680 | void trace_softirqs_on(unsigned long ip) | |
2681 | { | |
2682 | struct task_struct *curr = current; | |
2683 | ||
dd4e5d3a | 2684 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2685 | return; |
2686 | ||
0119fee4 PZ |
2687 | /* |
2688 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2689 | * funny state and nesting things. | |
2690 | */ | |
8e18257d PZ |
2691 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2692 | return; | |
2693 | ||
2694 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2695 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2696 | return; |
2697 | } | |
2698 | ||
dd4e5d3a | 2699 | current->lockdep_recursion = 1; |
8e18257d PZ |
2700 | /* |
2701 | * We'll do an OFF -> ON transition: | |
2702 | */ | |
2703 | curr->softirqs_enabled = 1; | |
2704 | curr->softirq_enable_ip = ip; | |
2705 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2706 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2707 | /* |
2708 | * We are going to turn softirqs on, so set the | |
2709 | * usage bit for all held locks, if hardirqs are | |
2710 | * enabled too: | |
2711 | */ | |
2712 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2713 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2714 | current->lockdep_recursion = 0; |
8e18257d PZ |
2715 | } |
2716 | ||
2717 | /* | |
2718 | * Softirqs were disabled: | |
2719 | */ | |
2720 | void trace_softirqs_off(unsigned long ip) | |
2721 | { | |
2722 | struct task_struct *curr = current; | |
2723 | ||
dd4e5d3a | 2724 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2725 | return; |
2726 | ||
0119fee4 PZ |
2727 | /* |
2728 | * We fancy IRQs being disabled here, see softirq.c | |
2729 | */ | |
8e18257d PZ |
2730 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2731 | return; | |
2732 | ||
2733 | if (curr->softirqs_enabled) { | |
2734 | /* | |
2735 | * We have done an ON -> OFF transition: | |
2736 | */ | |
2737 | curr->softirqs_enabled = 0; | |
2738 | curr->softirq_disable_ip = ip; | |
2739 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2740 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
2741 | /* |
2742 | * Whoops, we wanted softirqs off, so why aren't they? | |
2743 | */ | |
8e18257d PZ |
2744 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2745 | } else | |
bd6d29c2 | 2746 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2747 | } |
2748 | ||
2f850181 | 2749 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2750 | { |
2751 | struct task_struct *curr = current; | |
2752 | ||
2753 | if (unlikely(!debug_locks)) | |
2754 | return; | |
2755 | ||
2756 | /* no reclaim without waiting on it */ | |
d0164adc | 2757 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) |
cf40bd16 NP |
2758 | return; |
2759 | ||
2760 | /* this guy won't enter reclaim */ | |
2761 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2762 | return; | |
2763 | ||
2764 | /* We're only interested __GFP_FS allocations for now */ | |
2765 | if (!(gfp_mask & __GFP_FS)) | |
2766 | return; | |
2767 | ||
0119fee4 PZ |
2768 | /* |
2769 | * Oi! Can't be having __GFP_FS allocations with IRQs disabled. | |
2770 | */ | |
2f850181 | 2771 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2772 | return; |
2773 | ||
2774 | mark_held_locks(curr, RECLAIM_FS); | |
2775 | } | |
2776 | ||
2f850181 PZ |
2777 | static void check_flags(unsigned long flags); |
2778 | ||
2779 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2780 | { | |
2781 | unsigned long flags; | |
2782 | ||
2783 | if (unlikely(current->lockdep_recursion)) | |
2784 | return; | |
2785 | ||
2786 | raw_local_irq_save(flags); | |
2787 | check_flags(flags); | |
2788 | current->lockdep_recursion = 1; | |
2789 | __lockdep_trace_alloc(gfp_mask, flags); | |
2790 | current->lockdep_recursion = 0; | |
2791 | raw_local_irq_restore(flags); | |
2792 | } | |
2793 | ||
8e18257d PZ |
2794 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2795 | { | |
2796 | /* | |
2797 | * If non-trylock use in a hardirq or softirq context, then | |
2798 | * mark the lock as used in these contexts: | |
2799 | */ | |
2800 | if (!hlock->trylock) { | |
2801 | if (hlock->read) { | |
2802 | if (curr->hardirq_context) | |
2803 | if (!mark_lock(curr, hlock, | |
2804 | LOCK_USED_IN_HARDIRQ_READ)) | |
2805 | return 0; | |
2806 | if (curr->softirq_context) | |
2807 | if (!mark_lock(curr, hlock, | |
2808 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2809 | return 0; | |
2810 | } else { | |
2811 | if (curr->hardirq_context) | |
2812 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2813 | return 0; | |
2814 | if (curr->softirq_context) | |
2815 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2816 | return 0; | |
2817 | } | |
2818 | } | |
2819 | if (!hlock->hardirqs_off) { | |
2820 | if (hlock->read) { | |
2821 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2822 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2823 | return 0; |
2824 | if (curr->softirqs_enabled) | |
2825 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2826 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2827 | return 0; |
2828 | } else { | |
2829 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2830 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2831 | return 0; |
2832 | if (curr->softirqs_enabled) | |
2833 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2834 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2835 | return 0; |
2836 | } | |
2837 | } | |
2838 | ||
cf40bd16 NP |
2839 | /* |
2840 | * We reuse the irq context infrastructure more broadly as a general | |
2841 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2842 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2843 | * allocation). | |
2844 | */ | |
2845 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2846 | if (hlock->read) { | |
2847 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2848 | return 0; | |
2849 | } else { | |
2850 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2851 | return 0; | |
2852 | } | |
2853 | } | |
2854 | ||
8e18257d PZ |
2855 | return 1; |
2856 | } | |
2857 | ||
2858 | static int separate_irq_context(struct task_struct *curr, | |
2859 | struct held_lock *hlock) | |
2860 | { | |
2861 | unsigned int depth = curr->lockdep_depth; | |
2862 | ||
2863 | /* | |
2864 | * Keep track of points where we cross into an interrupt context: | |
2865 | */ | |
2866 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2867 | curr->softirq_context; | |
2868 | if (depth) { | |
2869 | struct held_lock *prev_hlock; | |
2870 | ||
2871 | prev_hlock = curr->held_locks + depth-1; | |
2872 | /* | |
2873 | * If we cross into another context, reset the | |
2874 | * hash key (this also prevents the checking and the | |
2875 | * adding of the dependency to 'prev'): | |
2876 | */ | |
2877 | if (prev_hlock->irq_context != hlock->irq_context) | |
2878 | return 1; | |
2879 | } | |
2880 | return 0; | |
fbb9ce95 IM |
2881 | } |
2882 | ||
0119fee4 | 2883 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 2884 | |
8e18257d PZ |
2885 | static inline |
2886 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2887 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2888 | { |
0119fee4 | 2889 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
2890 | return 1; |
2891 | } | |
fbb9ce95 | 2892 | |
8e18257d PZ |
2893 | static inline int mark_irqflags(struct task_struct *curr, |
2894 | struct held_lock *hlock) | |
2895 | { | |
2896 | return 1; | |
2897 | } | |
fbb9ce95 | 2898 | |
8e18257d PZ |
2899 | static inline int separate_irq_context(struct task_struct *curr, |
2900 | struct held_lock *hlock) | |
2901 | { | |
2902 | return 0; | |
fbb9ce95 IM |
2903 | } |
2904 | ||
868a23a8 PZ |
2905 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2906 | { | |
2907 | } | |
2908 | ||
0119fee4 | 2909 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
2910 | |
2911 | /* | |
8e18257d | 2912 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2913 | */ |
1d09daa5 | 2914 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2915 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2916 | { |
8e18257d | 2917 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2918 | |
2919 | /* | |
8e18257d PZ |
2920 | * If already set then do not dirty the cacheline, |
2921 | * nor do any checks: | |
fbb9ce95 | 2922 | */ |
f82b217e | 2923 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2924 | return 1; |
2925 | ||
2926 | if (!graph_lock()) | |
2927 | return 0; | |
fbb9ce95 | 2928 | /* |
25985edc | 2929 | * Make sure we didn't race: |
fbb9ce95 | 2930 | */ |
f82b217e | 2931 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2932 | graph_unlock(); |
2933 | return 1; | |
2934 | } | |
fbb9ce95 | 2935 | |
f82b217e | 2936 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2937 | |
f82b217e | 2938 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2939 | return 0; |
fbb9ce95 | 2940 | |
8e18257d | 2941 | switch (new_bit) { |
5346417e PZ |
2942 | #define LOCKDEP_STATE(__STATE) \ |
2943 | case LOCK_USED_IN_##__STATE: \ | |
2944 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2945 | case LOCK_ENABLED_##__STATE: \ | |
2946 | case LOCK_ENABLED_##__STATE##_READ: | |
2947 | #include "lockdep_states.h" | |
2948 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2949 | ret = mark_lock_irq(curr, this, new_bit); |
2950 | if (!ret) | |
2951 | return 0; | |
2952 | break; | |
2953 | case LOCK_USED: | |
bd6d29c2 | 2954 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
2955 | break; |
2956 | default: | |
2957 | if (!debug_locks_off_graph_unlock()) | |
2958 | return 0; | |
2959 | WARN_ON(1); | |
2960 | return 0; | |
2961 | } | |
fbb9ce95 | 2962 | |
8e18257d PZ |
2963 | graph_unlock(); |
2964 | ||
2965 | /* | |
2966 | * We must printk outside of the graph_lock: | |
2967 | */ | |
2968 | if (ret == 2) { | |
2969 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2970 | print_lock(this); | |
2971 | print_irqtrace_events(curr); | |
2972 | dump_stack(); | |
2973 | } | |
2974 | ||
2975 | return ret; | |
2976 | } | |
fbb9ce95 IM |
2977 | |
2978 | /* | |
2979 | * Initialize a lock instance's lock-class mapping info: | |
2980 | */ | |
2981 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2982 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2983 | { |
d3d03d4f YZ |
2984 | int i; |
2985 | ||
2986 | kmemcheck_mark_initialized(lock, sizeof(*lock)); | |
2987 | ||
2988 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) | |
2989 | lock->class_cache[i] = NULL; | |
62016250 | 2990 | |
c8a25005 PZ |
2991 | #ifdef CONFIG_LOCK_STAT |
2992 | lock->cpu = raw_smp_processor_id(); | |
2993 | #endif | |
2994 | ||
0119fee4 PZ |
2995 | /* |
2996 | * Can't be having no nameless bastards around this place! | |
2997 | */ | |
c8a25005 PZ |
2998 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
2999 | lock->name = "NULL"; | |
fbb9ce95 | 3000 | return; |
c8a25005 PZ |
3001 | } |
3002 | ||
3003 | lock->name = name; | |
fbb9ce95 | 3004 | |
0119fee4 PZ |
3005 | /* |
3006 | * No key, no joy, we need to hash something. | |
3007 | */ | |
fbb9ce95 IM |
3008 | if (DEBUG_LOCKS_WARN_ON(!key)) |
3009 | return; | |
fbb9ce95 IM |
3010 | /* |
3011 | * Sanity check, the lock-class key must be persistent: | |
3012 | */ | |
3013 | if (!static_obj(key)) { | |
3014 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
3015 | /* |
3016 | * What it says above ^^^^^, I suggest you read it. | |
3017 | */ | |
fbb9ce95 IM |
3018 | DEBUG_LOCKS_WARN_ON(1); |
3019 | return; | |
3020 | } | |
fbb9ce95 | 3021 | lock->key = key; |
c8a25005 PZ |
3022 | |
3023 | if (unlikely(!debug_locks)) | |
3024 | return; | |
3025 | ||
35a9393c PZ |
3026 | if (subclass) { |
3027 | unsigned long flags; | |
3028 | ||
3029 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3030 | return; | |
3031 | ||
3032 | raw_local_irq_save(flags); | |
3033 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3034 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3035 | current->lockdep_recursion = 0; |
3036 | raw_local_irq_restore(flags); | |
3037 | } | |
fbb9ce95 | 3038 | } |
fbb9ce95 IM |
3039 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3040 | ||
1704f47b | 3041 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3042 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3043 | |
d0945950 ML |
3044 | static int |
3045 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3046 | struct held_lock *hlock, | |
3047 | unsigned long ip) | |
3048 | { | |
3049 | if (!debug_locks_off()) | |
3050 | return 0; | |
3051 | if (debug_locks_silent) | |
3052 | return 0; | |
3053 | ||
3054 | printk("\n"); | |
3055 | printk("==================================\n"); | |
3056 | printk("[ BUG: Nested lock was not taken ]\n"); | |
3057 | print_kernel_ident(); | |
3058 | printk("----------------------------------\n"); | |
3059 | ||
3060 | printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); | |
3061 | print_lock(hlock); | |
3062 | ||
3063 | printk("\nbut this task is not holding:\n"); | |
3064 | printk("%s\n", hlock->nest_lock->name); | |
3065 | ||
3066 | printk("\nstack backtrace:\n"); | |
3067 | dump_stack(); | |
3068 | ||
3069 | printk("\nother info that might help us debug this:\n"); | |
3070 | lockdep_print_held_locks(curr); | |
3071 | ||
3072 | printk("\nstack backtrace:\n"); | |
3073 | dump_stack(); | |
3074 | ||
3075 | return 0; | |
3076 | } | |
3077 | ||
3078 | static int __lock_is_held(struct lockdep_map *lock); | |
3079 | ||
fbb9ce95 IM |
3080 | /* |
3081 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3082 | * We maintain the dependency maps and validate the locking attempt: | |
3083 | */ | |
3084 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3085 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3086 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3087 | int references, int pin_count) |
fbb9ce95 IM |
3088 | { |
3089 | struct task_struct *curr = current; | |
d6d897ce | 3090 | struct lock_class *class = NULL; |
fbb9ce95 | 3091 | struct held_lock *hlock; |
5f18ab5c | 3092 | unsigned int depth; |
fbb9ce95 | 3093 | int chain_head = 0; |
bb97a91e | 3094 | int class_idx; |
fbb9ce95 IM |
3095 | u64 chain_key; |
3096 | ||
3097 | if (unlikely(!debug_locks)) | |
3098 | return 0; | |
3099 | ||
0119fee4 PZ |
3100 | /* |
3101 | * Lockdep should run with IRQs disabled, otherwise we could | |
3102 | * get an interrupt which would want to take locks, which would | |
3103 | * end up in lockdep and have you got a head-ache already? | |
3104 | */ | |
fbb9ce95 IM |
3105 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3106 | return 0; | |
3107 | ||
fb9edbe9 ON |
3108 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3109 | check = 0; | |
1704f47b | 3110 | |
62016250 HM |
3111 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3112 | class = lock->class_cache[subclass]; | |
d6d897ce | 3113 | /* |
62016250 | 3114 | * Not cached? |
d6d897ce | 3115 | */ |
fbb9ce95 | 3116 | if (unlikely(!class)) { |
4dfbb9d8 | 3117 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3118 | if (!class) |
3119 | return 0; | |
3120 | } | |
bd6d29c2 | 3121 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3122 | if (very_verbose(class)) { |
3123 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3124 | if (class->name_version > 1) | |
3125 | printk("#%d", class->name_version); | |
3126 | printk("\n"); | |
3127 | dump_stack(); | |
3128 | } | |
3129 | ||
3130 | /* | |
3131 | * Add the lock to the list of currently held locks. | |
3132 | * (we dont increase the depth just yet, up until the | |
3133 | * dependency checks are done) | |
3134 | */ | |
3135 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3136 | /* |
3137 | * Ran out of static storage for our per-task lock stack again have we? | |
3138 | */ | |
fbb9ce95 IM |
3139 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3140 | return 0; | |
3141 | ||
bb97a91e PZ |
3142 | class_idx = class - lock_classes + 1; |
3143 | ||
3144 | if (depth) { | |
3145 | hlock = curr->held_locks + depth - 1; | |
3146 | if (hlock->class_idx == class_idx && nest_lock) { | |
3147 | if (hlock->references) | |
3148 | hlock->references++; | |
3149 | else | |
3150 | hlock->references = 2; | |
3151 | ||
3152 | return 1; | |
3153 | } | |
3154 | } | |
3155 | ||
fbb9ce95 | 3156 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3157 | /* |
3158 | * Plain impossible, we just registered it and checked it weren't no | |
3159 | * NULL like.. I bet this mushroom I ate was good! | |
3160 | */ | |
f82b217e DJ |
3161 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3162 | return 0; | |
bb97a91e | 3163 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3164 | hlock->acquire_ip = ip; |
3165 | hlock->instance = lock; | |
7531e2f3 | 3166 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
3167 | hlock->trylock = trylock; |
3168 | hlock->read = read; | |
3169 | hlock->check = check; | |
6951b12a | 3170 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3171 | hlock->references = references; |
f20786ff PZ |
3172 | #ifdef CONFIG_LOCK_STAT |
3173 | hlock->waittime_stamp = 0; | |
3365e779 | 3174 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3175 | #endif |
21199f27 | 3176 | hlock->pin_count = pin_count; |
fbb9ce95 | 3177 | |
fb9edbe9 | 3178 | if (check && !mark_irqflags(curr, hlock)) |
8e18257d PZ |
3179 | return 0; |
3180 | ||
fbb9ce95 | 3181 | /* mark it as used: */ |
4ff773bb | 3182 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3183 | return 0; |
8e18257d | 3184 | |
fbb9ce95 | 3185 | /* |
17aacfb9 | 3186 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3187 | * lock keys along the dependency chain. We save the hash value |
3188 | * at every step so that we can get the current hash easily | |
3189 | * after unlock. The chain hash is then used to cache dependency | |
3190 | * results. | |
3191 | * | |
3192 | * The 'key ID' is what is the most compact key value to drive | |
3193 | * the hash, not class->key. | |
3194 | */ | |
0119fee4 PZ |
3195 | /* |
3196 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3197 | */ | |
5f18ab5c | 3198 | if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) |
fbb9ce95 IM |
3199 | return 0; |
3200 | ||
3201 | chain_key = curr->curr_chain_key; | |
3202 | if (!depth) { | |
0119fee4 PZ |
3203 | /* |
3204 | * How can we have a chain hash when we ain't got no keys?! | |
3205 | */ | |
fbb9ce95 IM |
3206 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3207 | return 0; | |
3208 | chain_head = 1; | |
3209 | } | |
3210 | ||
3211 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3212 | if (separate_irq_context(curr, hlock)) { |
3213 | chain_key = 0; | |
3214 | chain_head = 1; | |
fbb9ce95 | 3215 | } |
5f18ab5c | 3216 | chain_key = iterate_chain_key(chain_key, class_idx); |
fbb9ce95 | 3217 | |
d0945950 ML |
3218 | if (nest_lock && !__lock_is_held(nest_lock)) |
3219 | return print_lock_nested_lock_not_held(curr, hlock, ip); | |
3220 | ||
3aa416b0 | 3221 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3222 | return 0; |
381a2292 | 3223 | |
3aa416b0 | 3224 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3225 | curr->lockdep_depth++; |
3226 | check_chain_key(curr); | |
60e114d1 JP |
3227 | #ifdef CONFIG_DEBUG_LOCKDEP |
3228 | if (unlikely(!debug_locks)) | |
3229 | return 0; | |
3230 | #endif | |
fbb9ce95 IM |
3231 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3232 | debug_locks_off(); | |
2c522836 DJ |
3233 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3234 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3235 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3236 | |
3237 | lockdep_print_held_locks(current); | |
3238 | debug_show_all_locks(); | |
eedeeabd | 3239 | dump_stack(); |
c0540606 | 3240 | |
fbb9ce95 IM |
3241 | return 0; |
3242 | } | |
381a2292 | 3243 | |
fbb9ce95 IM |
3244 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3245 | max_lockdep_depth = curr->lockdep_depth; | |
3246 | ||
3247 | return 1; | |
3248 | } | |
3249 | ||
3250 | static int | |
f86f7554 | 3251 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3252 | unsigned long ip) |
3253 | { | |
3254 | if (!debug_locks_off()) | |
3255 | return 0; | |
3256 | if (debug_locks_silent) | |
3257 | return 0; | |
3258 | ||
b3fbab05 PM |
3259 | printk("\n"); |
3260 | printk("=====================================\n"); | |
3261 | printk("[ BUG: bad unlock balance detected! ]\n"); | |
fbdc4b9a | 3262 | print_kernel_ident(); |
b3fbab05 | 3263 | printk("-------------------------------------\n"); |
fbb9ce95 | 3264 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3265 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3266 | print_lockdep_cache(lock); |
3267 | printk(") at:\n"); | |
3268 | print_ip_sym(ip); | |
3269 | printk("but there are no more locks to release!\n"); | |
3270 | printk("\nother info that might help us debug this:\n"); | |
3271 | lockdep_print_held_locks(curr); | |
3272 | ||
3273 | printk("\nstack backtrace:\n"); | |
3274 | dump_stack(); | |
3275 | ||
3276 | return 0; | |
3277 | } | |
3278 | ||
bb97a91e PZ |
3279 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3280 | { | |
3281 | if (hlock->instance == lock) | |
3282 | return 1; | |
3283 | ||
3284 | if (hlock->references) { | |
62016250 | 3285 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3286 | |
3287 | if (!class) | |
3288 | class = look_up_lock_class(lock, 0); | |
3289 | ||
80e0401e PZ |
3290 | /* |
3291 | * If look_up_lock_class() failed to find a class, we're trying | |
3292 | * to test if we hold a lock that has never yet been acquired. | |
3293 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3294 | * holding it either, so report failure. | |
3295 | */ | |
3296 | if (!class) | |
bb97a91e PZ |
3297 | return 0; |
3298 | ||
0119fee4 PZ |
3299 | /* |
3300 | * References, but not a lock we're actually ref-counting? | |
3301 | * State got messed up, follow the sites that change ->references | |
3302 | * and try to make sense of it. | |
3303 | */ | |
bb97a91e PZ |
3304 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3305 | return 0; | |
3306 | ||
3307 | if (hlock->class_idx == class - lock_classes + 1) | |
3308 | return 1; | |
3309 | } | |
3310 | ||
3311 | return 0; | |
3312 | } | |
3313 | ||
64aa348e | 3314 | static int |
00ef9f73 PZ |
3315 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3316 | struct lock_class_key *key, unsigned int subclass, | |
3317 | unsigned long ip) | |
64aa348e PZ |
3318 | { |
3319 | struct task_struct *curr = current; | |
3320 | struct held_lock *hlock, *prev_hlock; | |
3321 | struct lock_class *class; | |
3322 | unsigned int depth; | |
3323 | int i; | |
3324 | ||
3325 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3326 | /* |
3327 | * This function is about (re)setting the class of a held lock, | |
3328 | * yet we're not actually holding any locks. Naughty user! | |
3329 | */ | |
64aa348e PZ |
3330 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3331 | return 0; | |
3332 | ||
3333 | prev_hlock = NULL; | |
3334 | for (i = depth-1; i >= 0; i--) { | |
3335 | hlock = curr->held_locks + i; | |
3336 | /* | |
3337 | * We must not cross into another context: | |
3338 | */ | |
3339 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3340 | break; | |
bb97a91e | 3341 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3342 | goto found_it; |
3343 | prev_hlock = hlock; | |
3344 | } | |
f86f7554 | 3345 | return print_unlock_imbalance_bug(curr, lock, ip); |
64aa348e PZ |
3346 | |
3347 | found_it: | |
00ef9f73 | 3348 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3349 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3350 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3351 | |
3352 | curr->lockdep_depth = i; | |
3353 | curr->curr_chain_key = hlock->prev_chain_key; | |
3354 | ||
3355 | for (; i < depth; i++) { | |
3356 | hlock = curr->held_locks + i; | |
3357 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3358 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3359 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3360 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3361 | hlock->references, hlock->pin_count)) |
64aa348e PZ |
3362 | return 0; |
3363 | } | |
3364 | ||
0119fee4 PZ |
3365 | /* |
3366 | * I took it apart and put it back together again, except now I have | |
3367 | * these 'spare' parts.. where shall I put them. | |
3368 | */ | |
64aa348e PZ |
3369 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3370 | return 0; | |
3371 | return 1; | |
3372 | } | |
3373 | ||
fbb9ce95 | 3374 | /* |
e0f56fd7 PZ |
3375 | * Remove the lock to the list of currently held locks - this gets |
3376 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3377 | * mutex_lock_interruptible()). | |
3378 | * | |
3379 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
3380 | */ |
3381 | static int | |
e0f56fd7 | 3382 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
fbb9ce95 | 3383 | { |
e0f56fd7 | 3384 | struct task_struct *curr = current; |
fbb9ce95 IM |
3385 | struct held_lock *hlock, *prev_hlock; |
3386 | unsigned int depth; | |
3387 | int i; | |
3388 | ||
e0f56fd7 PZ |
3389 | if (unlikely(!debug_locks)) |
3390 | return 0; | |
3391 | ||
fbb9ce95 | 3392 | depth = curr->lockdep_depth; |
0119fee4 PZ |
3393 | /* |
3394 | * So we're all set to release this lock.. wait what lock? We don't | |
3395 | * own any locks, you've been drinking again? | |
3396 | */ | |
e0f56fd7 PZ |
3397 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
3398 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3399 | |
e0f56fd7 PZ |
3400 | /* |
3401 | * Check whether the lock exists in the current stack | |
3402 | * of held locks: | |
3403 | */ | |
fbb9ce95 IM |
3404 | prev_hlock = NULL; |
3405 | for (i = depth-1; i >= 0; i--) { | |
3406 | hlock = curr->held_locks + i; | |
3407 | /* | |
3408 | * We must not cross into another context: | |
3409 | */ | |
3410 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3411 | break; | |
bb97a91e | 3412 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3413 | goto found_it; |
3414 | prev_hlock = hlock; | |
3415 | } | |
f86f7554 | 3416 | return print_unlock_imbalance_bug(curr, lock, ip); |
fbb9ce95 IM |
3417 | |
3418 | found_it: | |
bb97a91e PZ |
3419 | if (hlock->instance == lock) |
3420 | lock_release_holdtime(hlock); | |
3421 | ||
a24fc60d PZ |
3422 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
3423 | ||
bb97a91e PZ |
3424 | if (hlock->references) { |
3425 | hlock->references--; | |
3426 | if (hlock->references) { | |
3427 | /* | |
3428 | * We had, and after removing one, still have | |
3429 | * references, the current lock stack is still | |
3430 | * valid. We're done! | |
3431 | */ | |
3432 | return 1; | |
3433 | } | |
3434 | } | |
f20786ff | 3435 | |
fbb9ce95 IM |
3436 | /* |
3437 | * We have the right lock to unlock, 'hlock' points to it. | |
3438 | * Now we remove it from the stack, and add back the other | |
3439 | * entries (if any), recalculating the hash along the way: | |
3440 | */ | |
bb97a91e | 3441 | |
fbb9ce95 IM |
3442 | curr->lockdep_depth = i; |
3443 | curr->curr_chain_key = hlock->prev_chain_key; | |
3444 | ||
3445 | for (i++; i < depth; i++) { | |
3446 | hlock = curr->held_locks + i; | |
3447 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3448 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3449 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3450 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3451 | hlock->references, hlock->pin_count)) |
fbb9ce95 IM |
3452 | return 0; |
3453 | } | |
3454 | ||
0119fee4 PZ |
3455 | /* |
3456 | * We had N bottles of beer on the wall, we drank one, but now | |
3457 | * there's not N-1 bottles of beer left on the wall... | |
3458 | */ | |
fbb9ce95 IM |
3459 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3460 | return 0; | |
f20786ff | 3461 | |
fbb9ce95 IM |
3462 | return 1; |
3463 | } | |
3464 | ||
f607c668 | 3465 | static int __lock_is_held(struct lockdep_map *lock) |
fbb9ce95 | 3466 | { |
f607c668 PZ |
3467 | struct task_struct *curr = current; |
3468 | int i; | |
fbb9ce95 | 3469 | |
f607c668 | 3470 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 3471 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 3472 | |
bb97a91e | 3473 | if (match_held_lock(hlock, lock)) |
f607c668 PZ |
3474 | return 1; |
3475 | } | |
f20786ff | 3476 | |
f607c668 | 3477 | return 0; |
fbb9ce95 IM |
3478 | } |
3479 | ||
a24fc60d | 3480 | static void __lock_pin_lock(struct lockdep_map *lock) |
fbb9ce95 IM |
3481 | { |
3482 | struct task_struct *curr = current; | |
a24fc60d | 3483 | int i; |
fbb9ce95 | 3484 | |
a24fc60d | 3485 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
3486 | return; |
3487 | ||
a24fc60d PZ |
3488 | for (i = 0; i < curr->lockdep_depth; i++) { |
3489 | struct held_lock *hlock = curr->held_locks + i; | |
3490 | ||
3491 | if (match_held_lock(hlock, lock)) { | |
3492 | hlock->pin_count++; | |
fbb9ce95 | 3493 | return; |
a24fc60d | 3494 | } |
fbb9ce95 IM |
3495 | } |
3496 | ||
a24fc60d | 3497 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
3498 | } |
3499 | ||
a24fc60d | 3500 | static void __lock_unpin_lock(struct lockdep_map *lock) |
f607c668 PZ |
3501 | { |
3502 | struct task_struct *curr = current; | |
3503 | int i; | |
3504 | ||
a24fc60d PZ |
3505 | if (unlikely(!debug_locks)) |
3506 | return; | |
3507 | ||
f607c668 | 3508 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
3509 | struct held_lock *hlock = curr->held_locks + i; |
3510 | ||
a24fc60d PZ |
3511 | if (match_held_lock(hlock, lock)) { |
3512 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
3513 | return; | |
3514 | ||
3515 | hlock->pin_count--; | |
3516 | return; | |
3517 | } | |
f607c668 PZ |
3518 | } |
3519 | ||
a24fc60d | 3520 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
3521 | } |
3522 | ||
fbb9ce95 IM |
3523 | /* |
3524 | * Check whether we follow the irq-flags state precisely: | |
3525 | */ | |
1d09daa5 | 3526 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3527 | { |
992860e9 IM |
3528 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3529 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3530 | if (!debug_locks) |
3531 | return; | |
3532 | ||
5f9fa8a6 IM |
3533 | if (irqs_disabled_flags(flags)) { |
3534 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3535 | printk("possible reason: unannotated irqs-off.\n"); | |
3536 | } | |
3537 | } else { | |
3538 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3539 | printk("possible reason: unannotated irqs-on.\n"); | |
3540 | } | |
3541 | } | |
fbb9ce95 IM |
3542 | |
3543 | /* | |
3544 | * We dont accurately track softirq state in e.g. | |
3545 | * hardirq contexts (such as on 4KSTACKS), so only | |
3546 | * check if not in hardirq contexts: | |
3547 | */ | |
3548 | if (!hardirq_count()) { | |
0119fee4 PZ |
3549 | if (softirq_count()) { |
3550 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3551 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3552 | } else { |
3553 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3554 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3555 | } |
fbb9ce95 IM |
3556 | } |
3557 | ||
3558 | if (!debug_locks) | |
3559 | print_irqtrace_events(current); | |
3560 | #endif | |
3561 | } | |
3562 | ||
00ef9f73 PZ |
3563 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3564 | struct lock_class_key *key, unsigned int subclass, | |
3565 | unsigned long ip) | |
64aa348e PZ |
3566 | { |
3567 | unsigned long flags; | |
3568 | ||
3569 | if (unlikely(current->lockdep_recursion)) | |
3570 | return; | |
3571 | ||
3572 | raw_local_irq_save(flags); | |
3573 | current->lockdep_recursion = 1; | |
3574 | check_flags(flags); | |
00ef9f73 | 3575 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3576 | check_chain_key(current); |
3577 | current->lockdep_recursion = 0; | |
3578 | raw_local_irq_restore(flags); | |
3579 | } | |
00ef9f73 | 3580 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3581 | |
fbb9ce95 IM |
3582 | /* |
3583 | * We are not always called with irqs disabled - do that here, | |
3584 | * and also avoid lockdep recursion: | |
3585 | */ | |
1d09daa5 | 3586 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3587 | int trylock, int read, int check, |
3588 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3589 | { |
3590 | unsigned long flags; | |
3591 | ||
3592 | if (unlikely(current->lockdep_recursion)) | |
3593 | return; | |
3594 | ||
3595 | raw_local_irq_save(flags); | |
3596 | check_flags(flags); | |
3597 | ||
3598 | current->lockdep_recursion = 1; | |
db2c4c77 | 3599 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3600 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 3601 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
3602 | current->lockdep_recursion = 0; |
3603 | raw_local_irq_restore(flags); | |
3604 | } | |
fbb9ce95 IM |
3605 | EXPORT_SYMBOL_GPL(lock_acquire); |
3606 | ||
1d09daa5 | 3607 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3608 | unsigned long ip) |
fbb9ce95 IM |
3609 | { |
3610 | unsigned long flags; | |
3611 | ||
3612 | if (unlikely(current->lockdep_recursion)) | |
3613 | return; | |
3614 | ||
3615 | raw_local_irq_save(flags); | |
3616 | check_flags(flags); | |
3617 | current->lockdep_recursion = 1; | |
93135439 | 3618 | trace_lock_release(lock, ip); |
e0f56fd7 PZ |
3619 | if (__lock_release(lock, nested, ip)) |
3620 | check_chain_key(current); | |
fbb9ce95 IM |
3621 | current->lockdep_recursion = 0; |
3622 | raw_local_irq_restore(flags); | |
3623 | } | |
fbb9ce95 IM |
3624 | EXPORT_SYMBOL_GPL(lock_release); |
3625 | ||
f607c668 PZ |
3626 | int lock_is_held(struct lockdep_map *lock) |
3627 | { | |
3628 | unsigned long flags; | |
3629 | int ret = 0; | |
3630 | ||
3631 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3632 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3633 | |
3634 | raw_local_irq_save(flags); | |
3635 | check_flags(flags); | |
3636 | ||
3637 | current->lockdep_recursion = 1; | |
3638 | ret = __lock_is_held(lock); | |
3639 | current->lockdep_recursion = 0; | |
3640 | raw_local_irq_restore(flags); | |
3641 | ||
3642 | return ret; | |
3643 | } | |
3644 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3645 | ||
a24fc60d PZ |
3646 | void lock_pin_lock(struct lockdep_map *lock) |
3647 | { | |
3648 | unsigned long flags; | |
3649 | ||
3650 | if (unlikely(current->lockdep_recursion)) | |
3651 | return; | |
3652 | ||
3653 | raw_local_irq_save(flags); | |
3654 | check_flags(flags); | |
3655 | ||
3656 | current->lockdep_recursion = 1; | |
3657 | __lock_pin_lock(lock); | |
3658 | current->lockdep_recursion = 0; | |
3659 | raw_local_irq_restore(flags); | |
3660 | } | |
3661 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
3662 | ||
3663 | void lock_unpin_lock(struct lockdep_map *lock) | |
3664 | { | |
3665 | unsigned long flags; | |
3666 | ||
3667 | if (unlikely(current->lockdep_recursion)) | |
3668 | return; | |
3669 | ||
3670 | raw_local_irq_save(flags); | |
3671 | check_flags(flags); | |
3672 | ||
3673 | current->lockdep_recursion = 1; | |
3674 | __lock_unpin_lock(lock); | |
3675 | current->lockdep_recursion = 0; | |
3676 | raw_local_irq_restore(flags); | |
3677 | } | |
3678 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
3679 | ||
cf40bd16 NP |
3680 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3681 | { | |
3682 | current->lockdep_reclaim_gfp = gfp_mask; | |
3683 | } | |
3684 | ||
3685 | void lockdep_clear_current_reclaim_state(void) | |
3686 | { | |
3687 | current->lockdep_reclaim_gfp = 0; | |
3688 | } | |
3689 | ||
f20786ff PZ |
3690 | #ifdef CONFIG_LOCK_STAT |
3691 | static int | |
3692 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3693 | unsigned long ip) | |
3694 | { | |
3695 | if (!debug_locks_off()) | |
3696 | return 0; | |
3697 | if (debug_locks_silent) | |
3698 | return 0; | |
3699 | ||
b3fbab05 PM |
3700 | printk("\n"); |
3701 | printk("=================================\n"); | |
3702 | printk("[ BUG: bad contention detected! ]\n"); | |
fbdc4b9a | 3703 | print_kernel_ident(); |
b3fbab05 | 3704 | printk("---------------------------------\n"); |
f20786ff | 3705 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3706 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3707 | print_lockdep_cache(lock); |
3708 | printk(") at:\n"); | |
3709 | print_ip_sym(ip); | |
3710 | printk("but there are no locks held!\n"); | |
3711 | printk("\nother info that might help us debug this:\n"); | |
3712 | lockdep_print_held_locks(curr); | |
3713 | ||
3714 | printk("\nstack backtrace:\n"); | |
3715 | dump_stack(); | |
3716 | ||
3717 | return 0; | |
3718 | } | |
3719 | ||
3720 | static void | |
3721 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3722 | { | |
3723 | struct task_struct *curr = current; | |
3724 | struct held_lock *hlock, *prev_hlock; | |
3725 | struct lock_class_stats *stats; | |
3726 | unsigned int depth; | |
c7e78cff | 3727 | int i, contention_point, contending_point; |
f20786ff PZ |
3728 | |
3729 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3730 | /* |
3731 | * Whee, we contended on this lock, except it seems we're not | |
3732 | * actually trying to acquire anything much at all.. | |
3733 | */ | |
f20786ff PZ |
3734 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3735 | return; | |
3736 | ||
3737 | prev_hlock = NULL; | |
3738 | for (i = depth-1; i >= 0; i--) { | |
3739 | hlock = curr->held_locks + i; | |
3740 | /* | |
3741 | * We must not cross into another context: | |
3742 | */ | |
3743 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3744 | break; | |
bb97a91e | 3745 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3746 | goto found_it; |
3747 | prev_hlock = hlock; | |
3748 | } | |
3749 | print_lock_contention_bug(curr, lock, ip); | |
3750 | return; | |
3751 | ||
3752 | found_it: | |
bb97a91e PZ |
3753 | if (hlock->instance != lock) |
3754 | return; | |
3755 | ||
3365e779 | 3756 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3757 | |
c7e78cff PZ |
3758 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3759 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3760 | lock->ip); | |
f20786ff | 3761 | |
f82b217e | 3762 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3763 | if (contention_point < LOCKSTAT_POINTS) |
3764 | stats->contention_point[contention_point]++; | |
3765 | if (contending_point < LOCKSTAT_POINTS) | |
3766 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3767 | if (lock->cpu != smp_processor_id()) |
3768 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3769 | put_lock_stats(stats); |
3770 | } | |
3771 | ||
3772 | static void | |
c7e78cff | 3773 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3774 | { |
3775 | struct task_struct *curr = current; | |
3776 | struct held_lock *hlock, *prev_hlock; | |
3777 | struct lock_class_stats *stats; | |
3778 | unsigned int depth; | |
3365e779 | 3779 | u64 now, waittime = 0; |
96645678 | 3780 | int i, cpu; |
f20786ff PZ |
3781 | |
3782 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3783 | /* |
3784 | * Yay, we acquired ownership of this lock we didn't try to | |
3785 | * acquire, how the heck did that happen? | |
3786 | */ | |
f20786ff PZ |
3787 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3788 | return; | |
3789 | ||
3790 | prev_hlock = NULL; | |
3791 | for (i = depth-1; i >= 0; i--) { | |
3792 | hlock = curr->held_locks + i; | |
3793 | /* | |
3794 | * We must not cross into another context: | |
3795 | */ | |
3796 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3797 | break; | |
bb97a91e | 3798 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3799 | goto found_it; |
3800 | prev_hlock = hlock; | |
3801 | } | |
3802 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3803 | return; | |
3804 | ||
3805 | found_it: | |
bb97a91e PZ |
3806 | if (hlock->instance != lock) |
3807 | return; | |
3808 | ||
96645678 PZ |
3809 | cpu = smp_processor_id(); |
3810 | if (hlock->waittime_stamp) { | |
3365e779 | 3811 | now = lockstat_clock(); |
96645678 PZ |
3812 | waittime = now - hlock->waittime_stamp; |
3813 | hlock->holdtime_stamp = now; | |
3814 | } | |
f20786ff | 3815 | |
883a2a31 | 3816 | trace_lock_acquired(lock, ip); |
2062501a | 3817 | |
f82b217e | 3818 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3819 | if (waittime) { |
3820 | if (hlock->read) | |
3821 | lock_time_inc(&stats->read_waittime, waittime); | |
3822 | else | |
3823 | lock_time_inc(&stats->write_waittime, waittime); | |
3824 | } | |
3825 | if (lock->cpu != cpu) | |
3826 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3827 | put_lock_stats(stats); |
96645678 PZ |
3828 | |
3829 | lock->cpu = cpu; | |
c7e78cff | 3830 | lock->ip = ip; |
f20786ff PZ |
3831 | } |
3832 | ||
3833 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3834 | { | |
3835 | unsigned long flags; | |
3836 | ||
3837 | if (unlikely(!lock_stat)) | |
3838 | return; | |
3839 | ||
3840 | if (unlikely(current->lockdep_recursion)) | |
3841 | return; | |
3842 | ||
3843 | raw_local_irq_save(flags); | |
3844 | check_flags(flags); | |
3845 | current->lockdep_recursion = 1; | |
db2c4c77 | 3846 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3847 | __lock_contended(lock, ip); |
3848 | current->lockdep_recursion = 0; | |
3849 | raw_local_irq_restore(flags); | |
3850 | } | |
3851 | EXPORT_SYMBOL_GPL(lock_contended); | |
3852 | ||
c7e78cff | 3853 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3854 | { |
3855 | unsigned long flags; | |
3856 | ||
3857 | if (unlikely(!lock_stat)) | |
3858 | return; | |
3859 | ||
3860 | if (unlikely(current->lockdep_recursion)) | |
3861 | return; | |
3862 | ||
3863 | raw_local_irq_save(flags); | |
3864 | check_flags(flags); | |
3865 | current->lockdep_recursion = 1; | |
c7e78cff | 3866 | __lock_acquired(lock, ip); |
f20786ff PZ |
3867 | current->lockdep_recursion = 0; |
3868 | raw_local_irq_restore(flags); | |
3869 | } | |
3870 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3871 | #endif | |
3872 | ||
fbb9ce95 IM |
3873 | /* |
3874 | * Used by the testsuite, sanitize the validator state | |
3875 | * after a simulated failure: | |
3876 | */ | |
3877 | ||
3878 | void lockdep_reset(void) | |
3879 | { | |
3880 | unsigned long flags; | |
23d95a03 | 3881 | int i; |
fbb9ce95 IM |
3882 | |
3883 | raw_local_irq_save(flags); | |
3884 | current->curr_chain_key = 0; | |
3885 | current->lockdep_depth = 0; | |
3886 | current->lockdep_recursion = 0; | |
3887 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3888 | nr_hardirq_chains = 0; | |
3889 | nr_softirq_chains = 0; | |
3890 | nr_process_chains = 0; | |
3891 | debug_locks = 1; | |
23d95a03 | 3892 | for (i = 0; i < CHAINHASH_SIZE; i++) |
a63f38cc | 3893 | INIT_HLIST_HEAD(chainhash_table + i); |
fbb9ce95 IM |
3894 | raw_local_irq_restore(flags); |
3895 | } | |
3896 | ||
3897 | static void zap_class(struct lock_class *class) | |
3898 | { | |
3899 | int i; | |
3900 | ||
3901 | /* | |
3902 | * Remove all dependencies this lock is | |
3903 | * involved in: | |
3904 | */ | |
3905 | for (i = 0; i < nr_list_entries; i++) { | |
3906 | if (list_entries[i].class == class) | |
3907 | list_del_rcu(&list_entries[i].entry); | |
3908 | } | |
3909 | /* | |
3910 | * Unhash the class and remove it from the all_lock_classes list: | |
3911 | */ | |
a63f38cc | 3912 | hlist_del_rcu(&class->hash_entry); |
fbb9ce95 IM |
3913 | list_del_rcu(&class->lock_entry); |
3914 | ||
cee34d88 PZ |
3915 | RCU_INIT_POINTER(class->key, NULL); |
3916 | RCU_INIT_POINTER(class->name, NULL); | |
fbb9ce95 IM |
3917 | } |
3918 | ||
fabe874a | 3919 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3920 | { |
3921 | return addr >= start && addr < start + size; | |
3922 | } | |
3923 | ||
35a9393c PZ |
3924 | /* |
3925 | * Used in module.c to remove lock classes from memory that is going to be | |
3926 | * freed; and possibly re-used by other modules. | |
3927 | * | |
3928 | * We will have had one sync_sched() before getting here, so we're guaranteed | |
3929 | * nobody will look up these exact classes -- they're properly dead but still | |
3930 | * allocated. | |
3931 | */ | |
fbb9ce95 IM |
3932 | void lockdep_free_key_range(void *start, unsigned long size) |
3933 | { | |
35a9393c | 3934 | struct lock_class *class; |
a63f38cc | 3935 | struct hlist_head *head; |
fbb9ce95 IM |
3936 | unsigned long flags; |
3937 | int i; | |
5a26db5b | 3938 | int locked; |
fbb9ce95 IM |
3939 | |
3940 | raw_local_irq_save(flags); | |
5a26db5b | 3941 | locked = graph_lock(); |
fbb9ce95 IM |
3942 | |
3943 | /* | |
3944 | * Unhash all classes that were created by this module: | |
3945 | */ | |
3946 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3947 | head = classhash_table + i; | |
a63f38cc | 3948 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
fbb9ce95 IM |
3949 | if (within(class->key, start, size)) |
3950 | zap_class(class); | |
fabe874a AV |
3951 | else if (within(class->name, start, size)) |
3952 | zap_class(class); | |
3953 | } | |
fbb9ce95 IM |
3954 | } |
3955 | ||
5a26db5b NP |
3956 | if (locked) |
3957 | graph_unlock(); | |
fbb9ce95 | 3958 | raw_local_irq_restore(flags); |
35a9393c PZ |
3959 | |
3960 | /* | |
3961 | * Wait for any possible iterators from look_up_lock_class() to pass | |
3962 | * before continuing to free the memory they refer to. | |
3963 | * | |
3964 | * sync_sched() is sufficient because the read-side is IRQ disable. | |
3965 | */ | |
3966 | synchronize_sched(); | |
3967 | ||
3968 | /* | |
3969 | * XXX at this point we could return the resources to the pool; | |
3970 | * instead we leak them. We would need to change to bitmap allocators | |
3971 | * instead of the linear allocators we have now. | |
3972 | */ | |
fbb9ce95 IM |
3973 | } |
3974 | ||
3975 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3976 | { | |
35a9393c | 3977 | struct lock_class *class; |
a63f38cc | 3978 | struct hlist_head *head; |
fbb9ce95 IM |
3979 | unsigned long flags; |
3980 | int i, j; | |
5a26db5b | 3981 | int locked; |
fbb9ce95 IM |
3982 | |
3983 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3984 | |
3985 | /* | |
d6d897ce IM |
3986 | * Remove all classes this lock might have: |
3987 | */ | |
3988 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3989 | /* | |
3990 | * If the class exists we look it up and zap it: | |
3991 | */ | |
3992 | class = look_up_lock_class(lock, j); | |
3993 | if (class) | |
3994 | zap_class(class); | |
3995 | } | |
3996 | /* | |
3997 | * Debug check: in the end all mapped classes should | |
3998 | * be gone. | |
fbb9ce95 | 3999 | */ |
5a26db5b | 4000 | locked = graph_lock(); |
fbb9ce95 IM |
4001 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
4002 | head = classhash_table + i; | |
a63f38cc | 4003 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
62016250 HM |
4004 | int match = 0; |
4005 | ||
4006 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
4007 | match |= class == lock->class_cache[j]; | |
4008 | ||
4009 | if (unlikely(match)) { | |
0119fee4 PZ |
4010 | if (debug_locks_off_graph_unlock()) { |
4011 | /* | |
4012 | * We all just reset everything, how did it match? | |
4013 | */ | |
74c383f1 | 4014 | WARN_ON(1); |
0119fee4 | 4015 | } |
d6d897ce | 4016 | goto out_restore; |
fbb9ce95 IM |
4017 | } |
4018 | } | |
4019 | } | |
5a26db5b NP |
4020 | if (locked) |
4021 | graph_unlock(); | |
d6d897ce IM |
4022 | |
4023 | out_restore: | |
fbb9ce95 IM |
4024 | raw_local_irq_restore(flags); |
4025 | } | |
4026 | ||
fbb9ce95 IM |
4027 | void __init lockdep_info(void) |
4028 | { | |
4029 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
4030 | ||
b0788caf | 4031 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
4032 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
4033 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 4034 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
4035 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
4036 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
4037 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
4038 | ||
4039 | printk(" memory used by lock dependency info: %lu kB\n", | |
4040 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
4041 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
4042 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
4043 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 4044 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 4045 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 4046 | + sizeof(struct circular_queue) |
4dd861d6 | 4047 | #endif |
90629209 | 4048 | ) / 1024 |
4dd861d6 | 4049 | ); |
fbb9ce95 IM |
4050 | |
4051 | printk(" per task-struct memory footprint: %lu bytes\n", | |
4052 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
fbb9ce95 IM |
4053 | } |
4054 | ||
fbb9ce95 IM |
4055 | static void |
4056 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 4057 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
4058 | { |
4059 | if (!debug_locks_off()) | |
4060 | return; | |
4061 | if (debug_locks_silent) | |
4062 | return; | |
4063 | ||
b3fbab05 PM |
4064 | printk("\n"); |
4065 | printk("=========================\n"); | |
4066 | printk("[ BUG: held lock freed! ]\n"); | |
fbdc4b9a | 4067 | print_kernel_ident(); |
b3fbab05 | 4068 | printk("-------------------------\n"); |
fbb9ce95 | 4069 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 4070 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 4071 | print_lock(hlock); |
fbb9ce95 IM |
4072 | lockdep_print_held_locks(curr); |
4073 | ||
4074 | printk("\nstack backtrace:\n"); | |
4075 | dump_stack(); | |
4076 | } | |
4077 | ||
54561783 ON |
4078 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4079 | const void* lock_from, unsigned long lock_len) | |
4080 | { | |
4081 | return lock_from + lock_len <= mem_from || | |
4082 | mem_from + mem_len <= lock_from; | |
4083 | } | |
4084 | ||
fbb9ce95 IM |
4085 | /* |
4086 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4087 | * is destroyed or reinitialized - this code checks whether there is | |
4088 | * any held lock in the memory range of <from> to <to>: | |
4089 | */ | |
4090 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4091 | { | |
fbb9ce95 IM |
4092 | struct task_struct *curr = current; |
4093 | struct held_lock *hlock; | |
4094 | unsigned long flags; | |
4095 | int i; | |
4096 | ||
4097 | if (unlikely(!debug_locks)) | |
4098 | return; | |
4099 | ||
4100 | local_irq_save(flags); | |
4101 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4102 | hlock = curr->held_locks + i; | |
4103 | ||
54561783 ON |
4104 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4105 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4106 | continue; |
4107 | ||
54561783 | 4108 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4109 | break; |
4110 | } | |
4111 | local_irq_restore(flags); | |
4112 | } | |
ed07536e | 4113 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 4114 | |
1b1d2fb4 | 4115 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
4116 | { |
4117 | if (!debug_locks_off()) | |
4118 | return; | |
4119 | if (debug_locks_silent) | |
4120 | return; | |
4121 | ||
b3fbab05 PM |
4122 | printk("\n"); |
4123 | printk("=====================================\n"); | |
1b1d2fb4 CC |
4124 | printk("[ BUG: %s/%d still has locks held! ]\n", |
4125 | current->comm, task_pid_nr(current)); | |
fbdc4b9a | 4126 | print_kernel_ident(); |
b3fbab05 | 4127 | printk("-------------------------------------\n"); |
1b1d2fb4 | 4128 | lockdep_print_held_locks(current); |
fbb9ce95 IM |
4129 | printk("\nstack backtrace:\n"); |
4130 | dump_stack(); | |
4131 | } | |
4132 | ||
1b1d2fb4 | 4133 | void debug_check_no_locks_held(void) |
fbb9ce95 | 4134 | { |
1b1d2fb4 CC |
4135 | if (unlikely(current->lockdep_depth > 0)) |
4136 | print_held_locks_bug(); | |
fbb9ce95 | 4137 | } |
1b1d2fb4 | 4138 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 4139 | |
8dce7a9a | 4140 | #ifdef __KERNEL__ |
fbb9ce95 IM |
4141 | void debug_show_all_locks(void) |
4142 | { | |
4143 | struct task_struct *g, *p; | |
4144 | int count = 10; | |
4145 | int unlock = 1; | |
4146 | ||
9c35dd7f JP |
4147 | if (unlikely(!debug_locks)) { |
4148 | printk("INFO: lockdep is turned off.\n"); | |
4149 | return; | |
4150 | } | |
fbb9ce95 IM |
4151 | printk("\nShowing all locks held in the system:\n"); |
4152 | ||
4153 | /* | |
4154 | * Here we try to get the tasklist_lock as hard as possible, | |
4155 | * if not successful after 2 seconds we ignore it (but keep | |
4156 | * trying). This is to enable a debug printout even if a | |
4157 | * tasklist_lock-holding task deadlocks or crashes. | |
4158 | */ | |
4159 | retry: | |
4160 | if (!read_trylock(&tasklist_lock)) { | |
4161 | if (count == 10) | |
4162 | printk("hm, tasklist_lock locked, retrying... "); | |
4163 | if (count) { | |
4164 | count--; | |
4165 | printk(" #%d", 10-count); | |
4166 | mdelay(200); | |
4167 | goto retry; | |
4168 | } | |
4169 | printk(" ignoring it.\n"); | |
4170 | unlock = 0; | |
46fec7ac | 4171 | } else { |
4172 | if (count != 10) | |
4173 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 4174 | } |
fbb9ce95 IM |
4175 | |
4176 | do_each_thread(g, p) { | |
85684873 IM |
4177 | /* |
4178 | * It's not reliable to print a task's held locks | |
4179 | * if it's not sleeping (or if it's not the current | |
4180 | * task): | |
4181 | */ | |
4182 | if (p->state == TASK_RUNNING && p != current) | |
4183 | continue; | |
fbb9ce95 IM |
4184 | if (p->lockdep_depth) |
4185 | lockdep_print_held_locks(p); | |
4186 | if (!unlock) | |
4187 | if (read_trylock(&tasklist_lock)) | |
4188 | unlock = 1; | |
4189 | } while_each_thread(g, p); | |
4190 | ||
4191 | printk("\n"); | |
4192 | printk("=============================================\n\n"); | |
4193 | ||
4194 | if (unlock) | |
4195 | read_unlock(&tasklist_lock); | |
4196 | } | |
fbb9ce95 | 4197 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 4198 | #endif |
fbb9ce95 | 4199 | |
82a1fcb9 IM |
4200 | /* |
4201 | * Careful: only use this function if you are sure that | |
4202 | * the task cannot run in parallel! | |
4203 | */ | |
f1b499f0 | 4204 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4205 | { |
9c35dd7f JP |
4206 | if (unlikely(!debug_locks)) { |
4207 | printk("INFO: lockdep is turned off.\n"); | |
4208 | return; | |
4209 | } | |
fbb9ce95 IM |
4210 | lockdep_print_held_locks(task); |
4211 | } | |
fbb9ce95 | 4212 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 4213 | |
722a9f92 | 4214 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
4215 | { |
4216 | struct task_struct *curr = current; | |
4217 | ||
4218 | if (unlikely(curr->lockdep_depth)) { | |
4219 | if (!debug_locks_off()) | |
4220 | return; | |
b3fbab05 PM |
4221 | printk("\n"); |
4222 | printk("================================================\n"); | |
4223 | printk("[ BUG: lock held when returning to user space! ]\n"); | |
fbdc4b9a | 4224 | print_kernel_ident(); |
b3fbab05 | 4225 | printk("------------------------------------------------\n"); |
b351d164 PZ |
4226 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4227 | curr->comm, curr->pid); | |
4228 | lockdep_print_held_locks(curr); | |
4229 | } | |
4230 | } | |
0632eb3d | 4231 | |
b3fbab05 | 4232 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4233 | { |
4234 | struct task_struct *curr = current; | |
4235 | ||
2b3fc35f | 4236 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4237 | if (!debug_locks_off()) |
4238 | return; | |
2b3fc35f LJ |
4239 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4240 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 PM |
4241 | printk("\n"); |
4242 | printk("===============================\n"); | |
4243 | printk("[ INFO: suspicious RCU usage. ]\n"); | |
fbdc4b9a | 4244 | print_kernel_ident(); |
b3fbab05 PM |
4245 | printk("-------------------------------\n"); |
4246 | printk("%s:%d %s!\n", file, line, s); | |
0632eb3d | 4247 | printk("\nother info that might help us debug this:\n\n"); |
c5fdcec9 PM |
4248 | printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n", |
4249 | !rcu_lockdep_current_cpu_online() | |
4250 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 4251 | : !rcu_is_watching() |
c5fdcec9 PM |
4252 | ? "RCU used illegally from idle CPU!\n" |
4253 | : "", | |
4254 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
4255 | |
4256 | /* | |
4257 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
4258 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
4259 | * considers that CPU to be in an "extended quiescent state", | |
4260 | * which means that RCU will be completely ignoring that CPU. | |
4261 | * Therefore, rcu_read_lock() and friends have absolutely no | |
4262 | * effect on a CPU running in that state. In other words, even if | |
4263 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
4264 | * delete data structures out from under it. RCU really has no | |
4265 | * choice here: we need to keep an RCU-free window in idle where | |
4266 | * the CPU may possibly enter into low power mode. This way we can | |
4267 | * notice an extended quiescent state to other CPUs that started a grace | |
4268 | * period. Otherwise we would delay any grace period as long as we run | |
4269 | * in the idle task. | |
4270 | * | |
4271 | * So complain bitterly if someone does call rcu_read_lock(), | |
4272 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
4273 | */ | |
5c173eb8 | 4274 | if (!rcu_is_watching()) |
0464e937 FW |
4275 | printk("RCU used illegally from extended quiescent state!\n"); |
4276 | ||
0632eb3d PM |
4277 | lockdep_print_held_locks(curr); |
4278 | printk("\nstack backtrace:\n"); | |
4279 | dump_stack(); | |
4280 | } | |
b3fbab05 | 4281 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |