Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
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> |
af012961 | 46 | |
fbb9ce95 IM |
47 | #include <asm/sections.h> |
48 | ||
49 | #include "lockdep_internals.h" | |
50 | ||
a8d154b0 | 51 | #define CREATE_TRACE_POINTS |
ad8d75ff | 52 | #include <trace/events/lockdep.h> |
a8d154b0 | 53 | |
f20786ff PZ |
54 | #ifdef CONFIG_PROVE_LOCKING |
55 | int prove_locking = 1; | |
56 | module_param(prove_locking, int, 0644); | |
57 | #else | |
58 | #define prove_locking 0 | |
59 | #endif | |
60 | ||
61 | #ifdef CONFIG_LOCK_STAT | |
62 | int lock_stat = 1; | |
63 | module_param(lock_stat, int, 0644); | |
64 | #else | |
65 | #define lock_stat 0 | |
66 | #endif | |
67 | ||
fbb9ce95 | 68 | /* |
74c383f1 IM |
69 | * lockdep_lock: protects the lockdep graph, the hashes and the |
70 | * class/list/hash allocators. | |
fbb9ce95 IM |
71 | * |
72 | * This is one of the rare exceptions where it's justified | |
73 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 74 | * code to recurse back into the lockdep code... |
fbb9ce95 | 75 | */ |
74c383f1 IM |
76 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
77 | ||
78 | static int graph_lock(void) | |
79 | { | |
80 | __raw_spin_lock(&lockdep_lock); | |
81 | /* | |
82 | * Make sure that if another CPU detected a bug while | |
83 | * walking the graph we dont change it (while the other | |
84 | * CPU is busy printing out stuff with the graph lock | |
85 | * dropped already) | |
86 | */ | |
87 | if (!debug_locks) { | |
88 | __raw_spin_unlock(&lockdep_lock); | |
89 | return 0; | |
90 | } | |
bb065afb SR |
91 | /* prevent any recursions within lockdep from causing deadlocks */ |
92 | current->lockdep_recursion++; | |
74c383f1 IM |
93 | return 1; |
94 | } | |
95 | ||
96 | static inline int graph_unlock(void) | |
97 | { | |
381a2292 JP |
98 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
99 | return DEBUG_LOCKS_WARN_ON(1); | |
100 | ||
bb065afb | 101 | current->lockdep_recursion--; |
74c383f1 IM |
102 | __raw_spin_unlock(&lockdep_lock); |
103 | return 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * Turn lock debugging off and return with 0 if it was off already, | |
108 | * and also release the graph lock: | |
109 | */ | |
110 | static inline int debug_locks_off_graph_unlock(void) | |
111 | { | |
112 | int ret = debug_locks_off(); | |
113 | ||
114 | __raw_spin_unlock(&lockdep_lock); | |
115 | ||
116 | return ret; | |
117 | } | |
fbb9ce95 IM |
118 | |
119 | static int lockdep_initialized; | |
120 | ||
121 | unsigned long nr_list_entries; | |
af012961 | 122 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 123 | |
fbb9ce95 IM |
124 | /* |
125 | * All data structures here are protected by the global debug_lock. | |
126 | * | |
127 | * Mutex key structs only get allocated, once during bootup, and never | |
128 | * get freed - this significantly simplifies the debugging code. | |
129 | */ | |
130 | unsigned long nr_lock_classes; | |
131 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
132 | ||
f82b217e DJ |
133 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
134 | { | |
135 | if (!hlock->class_idx) { | |
136 | DEBUG_LOCKS_WARN_ON(1); | |
137 | return NULL; | |
138 | } | |
139 | return lock_classes + hlock->class_idx - 1; | |
140 | } | |
141 | ||
f20786ff PZ |
142 | #ifdef CONFIG_LOCK_STAT |
143 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); | |
144 | ||
c7e78cff | 145 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
146 | { |
147 | int i; | |
148 | ||
c7e78cff PZ |
149 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
150 | if (points[i] == 0) { | |
151 | points[i] = ip; | |
f20786ff PZ |
152 | break; |
153 | } | |
c7e78cff | 154 | if (points[i] == ip) |
f20786ff PZ |
155 | break; |
156 | } | |
157 | ||
158 | return i; | |
159 | } | |
160 | ||
161 | static void lock_time_inc(struct lock_time *lt, s64 time) | |
162 | { | |
163 | if (time > lt->max) | |
164 | lt->max = time; | |
165 | ||
166 | if (time < lt->min || !lt->min) | |
167 | lt->min = time; | |
168 | ||
169 | lt->total += time; | |
170 | lt->nr++; | |
171 | } | |
172 | ||
c46261de PZ |
173 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
174 | { | |
175 | dst->min += src->min; | |
176 | dst->max += src->max; | |
177 | dst->total += src->total; | |
178 | dst->nr += src->nr; | |
179 | } | |
180 | ||
181 | struct lock_class_stats lock_stats(struct lock_class *class) | |
182 | { | |
183 | struct lock_class_stats stats; | |
184 | int cpu, i; | |
185 | ||
186 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
187 | for_each_possible_cpu(cpu) { | |
188 | struct lock_class_stats *pcs = | |
189 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
190 | ||
191 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
192 | stats.contention_point[i] += pcs->contention_point[i]; | |
193 | ||
c7e78cff PZ |
194 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
195 | stats.contending_point[i] += pcs->contending_point[i]; | |
196 | ||
c46261de PZ |
197 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
198 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
199 | ||
200 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
201 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
202 | |
203 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
204 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
205 | } |
206 | ||
207 | return stats; | |
208 | } | |
209 | ||
210 | void clear_lock_stats(struct lock_class *class) | |
211 | { | |
212 | int cpu; | |
213 | ||
214 | for_each_possible_cpu(cpu) { | |
215 | struct lock_class_stats *cpu_stats = | |
216 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
217 | ||
218 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
219 | } | |
220 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 221 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
222 | } |
223 | ||
f20786ff PZ |
224 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
225 | { | |
226 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
227 | } | |
228 | ||
229 | static void put_lock_stats(struct lock_class_stats *stats) | |
230 | { | |
231 | put_cpu_var(lock_stats); | |
232 | } | |
233 | ||
234 | static void lock_release_holdtime(struct held_lock *hlock) | |
235 | { | |
236 | struct lock_class_stats *stats; | |
237 | s64 holdtime; | |
238 | ||
239 | if (!lock_stat) | |
240 | return; | |
241 | ||
242 | holdtime = sched_clock() - hlock->holdtime_stamp; | |
243 | ||
f82b217e | 244 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
245 | if (hlock->read) |
246 | lock_time_inc(&stats->read_holdtime, holdtime); | |
247 | else | |
248 | lock_time_inc(&stats->write_holdtime, holdtime); | |
249 | put_lock_stats(stats); | |
250 | } | |
251 | #else | |
252 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
253 | { | |
254 | } | |
255 | #endif | |
256 | ||
fbb9ce95 IM |
257 | /* |
258 | * We keep a global list of all lock classes. The list only grows, | |
259 | * never shrinks. The list is only accessed with the lockdep | |
260 | * spinlock lock held. | |
261 | */ | |
262 | LIST_HEAD(all_lock_classes); | |
263 | ||
264 | /* | |
265 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
266 | */ | |
267 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
268 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 269 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
270 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
271 | ||
272 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
273 | ||
fbb9ce95 IM |
274 | /* |
275 | * We put the lock dependency chains into a hash-table as well, to cache | |
276 | * their existence: | |
277 | */ | |
278 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
279 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 280 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
281 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
282 | ||
283 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
284 | ||
285 | /* | |
286 | * The hash key of the lock dependency chains is a hash itself too: | |
287 | * it's a hash of all locks taken up to that lock, including that lock. | |
288 | * It's a 64-bit hash, because it's important for the keys to be | |
289 | * unique. | |
290 | */ | |
291 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
292 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
293 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
294 | (key2)) |
295 | ||
1d09daa5 | 296 | void lockdep_off(void) |
fbb9ce95 IM |
297 | { |
298 | current->lockdep_recursion++; | |
299 | } | |
fbb9ce95 IM |
300 | EXPORT_SYMBOL(lockdep_off); |
301 | ||
1d09daa5 | 302 | void lockdep_on(void) |
fbb9ce95 IM |
303 | { |
304 | current->lockdep_recursion--; | |
305 | } | |
fbb9ce95 IM |
306 | EXPORT_SYMBOL(lockdep_on); |
307 | ||
fbb9ce95 IM |
308 | /* |
309 | * Debugging switches: | |
310 | */ | |
311 | ||
312 | #define VERBOSE 0 | |
33e94e96 | 313 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
314 | |
315 | #if VERBOSE | |
316 | # define HARDIRQ_VERBOSE 1 | |
317 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 318 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
319 | #else |
320 | # define HARDIRQ_VERBOSE 0 | |
321 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 322 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
323 | #endif |
324 | ||
cf40bd16 | 325 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
326 | /* |
327 | * Quick filtering for interesting events: | |
328 | */ | |
329 | static int class_filter(struct lock_class *class) | |
330 | { | |
f9829cce AK |
331 | #if 0 |
332 | /* Example */ | |
fbb9ce95 | 333 | if (class->name_version == 1 && |
f9829cce | 334 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
335 | return 1; |
336 | if (class->name_version == 1 && | |
f9829cce | 337 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 338 | return 1; |
f9829cce | 339 | #endif |
a6640897 IM |
340 | /* Filter everything else. 1 would be to allow everything else */ |
341 | return 0; | |
fbb9ce95 IM |
342 | } |
343 | #endif | |
344 | ||
345 | static int verbose(struct lock_class *class) | |
346 | { | |
347 | #if VERBOSE | |
348 | return class_filter(class); | |
349 | #endif | |
350 | return 0; | |
351 | } | |
352 | ||
fbb9ce95 IM |
353 | /* |
354 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 355 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
356 | */ |
357 | unsigned long nr_stack_trace_entries; | |
358 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
359 | ||
360 | static int save_trace(struct stack_trace *trace) | |
361 | { | |
362 | trace->nr_entries = 0; | |
363 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
364 | trace->entries = stack_trace + nr_stack_trace_entries; | |
365 | ||
5a1b3999 | 366 | trace->skip = 3; |
5a1b3999 | 367 | |
ab1b6f03 | 368 | save_stack_trace(trace); |
fbb9ce95 | 369 | |
4f84f433 PZ |
370 | /* |
371 | * Some daft arches put -1 at the end to indicate its a full trace. | |
372 | * | |
373 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
374 | * complete trace that maxes out the entries provided will be reported | |
375 | * as incomplete, friggin useless </rant> | |
376 | */ | |
377 | if (trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
378 | trace->nr_entries--; | |
379 | ||
fbb9ce95 IM |
380 | trace->max_entries = trace->nr_entries; |
381 | ||
382 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 383 | |
4f84f433 | 384 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
385 | if (!debug_locks_off_graph_unlock()) |
386 | return 0; | |
387 | ||
388 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
389 | printk("turning off the locking correctness validator.\n"); | |
390 | dump_stack(); | |
391 | ||
fbb9ce95 IM |
392 | return 0; |
393 | } | |
394 | ||
395 | return 1; | |
396 | } | |
397 | ||
398 | unsigned int nr_hardirq_chains; | |
399 | unsigned int nr_softirq_chains; | |
400 | unsigned int nr_process_chains; | |
401 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
402 | |
403 | #ifdef CONFIG_DEBUG_LOCKDEP | |
404 | /* | |
405 | * We cannot printk in early bootup code. Not even early_printk() | |
406 | * might work. So we mark any initialization errors and printk | |
407 | * about it later on, in lockdep_info(). | |
408 | */ | |
409 | static int lockdep_init_error; | |
c71063c9 JB |
410 | static unsigned long lockdep_init_trace_data[20]; |
411 | static struct stack_trace lockdep_init_trace = { | |
412 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
413 | .entries = lockdep_init_trace_data, | |
414 | }; | |
fbb9ce95 IM |
415 | |
416 | /* | |
417 | * Various lockdep statistics: | |
418 | */ | |
419 | atomic_t chain_lookup_hits; | |
420 | atomic_t chain_lookup_misses; | |
421 | atomic_t hardirqs_on_events; | |
422 | atomic_t hardirqs_off_events; | |
423 | atomic_t redundant_hardirqs_on; | |
424 | atomic_t redundant_hardirqs_off; | |
425 | atomic_t softirqs_on_events; | |
426 | atomic_t softirqs_off_events; | |
427 | atomic_t redundant_softirqs_on; | |
428 | atomic_t redundant_softirqs_off; | |
429 | atomic_t nr_unused_locks; | |
430 | atomic_t nr_cyclic_checks; | |
fbb9ce95 | 431 | atomic_t nr_find_usage_forwards_checks; |
fbb9ce95 | 432 | atomic_t nr_find_usage_backwards_checks; |
fbb9ce95 IM |
433 | #endif |
434 | ||
435 | /* | |
436 | * Locking printouts: | |
437 | */ | |
438 | ||
fabe9c42 | 439 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
440 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
441 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
442 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
443 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 444 | |
fbb9ce95 IM |
445 | static const char *usage_str[] = |
446 | { | |
fabe9c42 PZ |
447 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
448 | #include "lockdep_states.h" | |
449 | #undef LOCKDEP_STATE | |
450 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
451 | }; |
452 | ||
453 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
454 | { | |
ffb45122 | 455 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
456 | } |
457 | ||
3ff176ca | 458 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 459 | { |
3ff176ca PZ |
460 | return 1UL << bit; |
461 | } | |
fbb9ce95 | 462 | |
3ff176ca PZ |
463 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
464 | { | |
465 | char c = '.'; | |
466 | ||
467 | if (class->usage_mask & lock_flag(bit + 2)) | |
468 | c = '+'; | |
469 | if (class->usage_mask & lock_flag(bit)) { | |
470 | c = '-'; | |
471 | if (class->usage_mask & lock_flag(bit + 2)) | |
472 | c = '?'; | |
fbb9ce95 IM |
473 | } |
474 | ||
3ff176ca PZ |
475 | return c; |
476 | } | |
cf40bd16 | 477 | |
f510b233 | 478 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 479 | { |
f510b233 | 480 | int i = 0; |
cf40bd16 | 481 | |
f510b233 PZ |
482 | #define LOCKDEP_STATE(__STATE) \ |
483 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
484 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
485 | #include "lockdep_states.h" | |
486 | #undef LOCKDEP_STATE | |
487 | ||
488 | usage[i] = '\0'; | |
fbb9ce95 IM |
489 | } |
490 | ||
491 | static void print_lock_name(struct lock_class *class) | |
492 | { | |
f510b233 | 493 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
494 | const char *name; |
495 | ||
f510b233 | 496 | get_usage_chars(class, usage); |
fbb9ce95 IM |
497 | |
498 | name = class->name; | |
499 | if (!name) { | |
500 | name = __get_key_name(class->key, str); | |
501 | printk(" (%s", name); | |
502 | } else { | |
503 | printk(" (%s", name); | |
504 | if (class->name_version > 1) | |
505 | printk("#%d", class->name_version); | |
506 | if (class->subclass) | |
507 | printk("/%d", class->subclass); | |
508 | } | |
f510b233 | 509 | printk("){%s}", usage); |
fbb9ce95 IM |
510 | } |
511 | ||
512 | static void print_lockdep_cache(struct lockdep_map *lock) | |
513 | { | |
514 | const char *name; | |
9281acea | 515 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
516 | |
517 | name = lock->name; | |
518 | if (!name) | |
519 | name = __get_key_name(lock->key->subkeys, str); | |
520 | ||
521 | printk("%s", name); | |
522 | } | |
523 | ||
524 | static void print_lock(struct held_lock *hlock) | |
525 | { | |
f82b217e | 526 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
527 | printk(", at: "); |
528 | print_ip_sym(hlock->acquire_ip); | |
529 | } | |
530 | ||
531 | static void lockdep_print_held_locks(struct task_struct *curr) | |
532 | { | |
533 | int i, depth = curr->lockdep_depth; | |
534 | ||
535 | if (!depth) { | |
ba25f9dc | 536 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
537 | return; |
538 | } | |
539 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 540 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
541 | |
542 | for (i = 0; i < depth; i++) { | |
543 | printk(" #%d: ", i); | |
544 | print_lock(curr->held_locks + i); | |
545 | } | |
546 | } | |
fbb9ce95 | 547 | |
8e18257d PZ |
548 | static void print_kernel_version(void) |
549 | { | |
550 | printk("%s %.*s\n", init_utsname()->release, | |
551 | (int)strcspn(init_utsname()->version, " "), | |
552 | init_utsname()->version); | |
553 | } | |
554 | ||
555 | static int very_verbose(struct lock_class *class) | |
556 | { | |
557 | #if VERY_VERBOSE | |
558 | return class_filter(class); | |
559 | #endif | |
560 | return 0; | |
561 | } | |
562 | ||
fbb9ce95 | 563 | /* |
8e18257d | 564 | * Is this the address of a static object: |
fbb9ce95 | 565 | */ |
8e18257d | 566 | static int static_obj(void *obj) |
fbb9ce95 | 567 | { |
8e18257d PZ |
568 | unsigned long start = (unsigned long) &_stext, |
569 | end = (unsigned long) &_end, | |
570 | addr = (unsigned long) obj; | |
571 | #ifdef CONFIG_SMP | |
572 | int i; | |
573 | #endif | |
574 | ||
fbb9ce95 | 575 | /* |
8e18257d | 576 | * static variable? |
fbb9ce95 | 577 | */ |
8e18257d PZ |
578 | if ((addr >= start) && (addr < end)) |
579 | return 1; | |
fbb9ce95 | 580 | |
8e18257d | 581 | #ifdef CONFIG_SMP |
fbb9ce95 | 582 | /* |
8e18257d | 583 | * percpu var? |
fbb9ce95 | 584 | */ |
8e18257d PZ |
585 | for_each_possible_cpu(i) { |
586 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
587 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
588 | + per_cpu_offset(i); | |
fbb9ce95 | 589 | |
8e18257d PZ |
590 | if ((addr >= start) && (addr < end)) |
591 | return 1; | |
592 | } | |
ca58abcb | 593 | #endif |
fbb9ce95 | 594 | |
8e18257d PZ |
595 | /* |
596 | * module var? | |
597 | */ | |
598 | return is_module_address(addr); | |
99de055a DJ |
599 | } |
600 | ||
fbb9ce95 | 601 | /* |
8e18257d PZ |
602 | * To make lock name printouts unique, we calculate a unique |
603 | * class->name_version generation counter: | |
fbb9ce95 | 604 | */ |
8e18257d | 605 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 606 | { |
8e18257d PZ |
607 | struct lock_class *class; |
608 | int count = 0; | |
fbb9ce95 | 609 | |
8e18257d | 610 | if (!new_class->name) |
fbb9ce95 IM |
611 | return 0; |
612 | ||
8e18257d PZ |
613 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
614 | if (new_class->key - new_class->subclass == class->key) | |
615 | return class->name_version; | |
616 | if (class->name && !strcmp(class->name, new_class->name)) | |
617 | count = max(count, class->name_version); | |
618 | } | |
fbb9ce95 | 619 | |
8e18257d | 620 | return count + 1; |
fbb9ce95 IM |
621 | } |
622 | ||
8e18257d PZ |
623 | /* |
624 | * Register a lock's class in the hash-table, if the class is not present | |
625 | * yet. Otherwise we look it up. We cache the result in the lock object | |
626 | * itself, so actual lookup of the hash should be once per lock object. | |
627 | */ | |
628 | static inline struct lock_class * | |
629 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 630 | { |
8e18257d PZ |
631 | struct lockdep_subclass_key *key; |
632 | struct list_head *hash_head; | |
633 | struct lock_class *class; | |
fbb9ce95 | 634 | |
8e18257d PZ |
635 | #ifdef CONFIG_DEBUG_LOCKDEP |
636 | /* | |
637 | * If the architecture calls into lockdep before initializing | |
638 | * the hashes then we'll warn about it later. (we cannot printk | |
639 | * right now) | |
640 | */ | |
641 | if (unlikely(!lockdep_initialized)) { | |
642 | lockdep_init(); | |
643 | lockdep_init_error = 1; | |
c71063c9 | 644 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
645 | } |
646 | #endif | |
fbb9ce95 | 647 | |
8e18257d PZ |
648 | /* |
649 | * Static locks do not have their class-keys yet - for them the key | |
650 | * is the lock object itself: | |
651 | */ | |
652 | if (unlikely(!lock->key)) | |
653 | lock->key = (void *)lock; | |
fbb9ce95 | 654 | |
8e18257d PZ |
655 | /* |
656 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
657 | * lock_class_key variable is passed in through the mutex_init() | |
658 | * (or spin_lock_init()) call - which acts as the key. For static | |
659 | * locks we use the lock object itself as the key. | |
660 | */ | |
4b32d0a4 PZ |
661 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
662 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 663 | |
8e18257d | 664 | key = lock->key->subkeys + subclass; |
ca268c69 | 665 | |
8e18257d | 666 | hash_head = classhashentry(key); |
74c383f1 | 667 | |
8e18257d PZ |
668 | /* |
669 | * We can walk the hash lockfree, because the hash only | |
670 | * grows, and we are careful when adding entries to the end: | |
671 | */ | |
4b32d0a4 PZ |
672 | list_for_each_entry(class, hash_head, hash_entry) { |
673 | if (class->key == key) { | |
674 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 675 | return class; |
4b32d0a4 PZ |
676 | } |
677 | } | |
fbb9ce95 | 678 | |
8e18257d | 679 | return NULL; |
fbb9ce95 IM |
680 | } |
681 | ||
682 | /* | |
8e18257d PZ |
683 | * Register a lock's class in the hash-table, if the class is not present |
684 | * yet. Otherwise we look it up. We cache the result in the lock object | |
685 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 686 | */ |
8e18257d PZ |
687 | static inline struct lock_class * |
688 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 689 | { |
8e18257d PZ |
690 | struct lockdep_subclass_key *key; |
691 | struct list_head *hash_head; | |
692 | struct lock_class *class; | |
693 | unsigned long flags; | |
694 | ||
695 | class = look_up_lock_class(lock, subclass); | |
696 | if (likely(class)) | |
697 | return class; | |
698 | ||
699 | /* | |
700 | * Debug-check: all keys must be persistent! | |
701 | */ | |
702 | if (!static_obj(lock->key)) { | |
703 | debug_locks_off(); | |
704 | printk("INFO: trying to register non-static key.\n"); | |
705 | printk("the code is fine but needs lockdep annotation.\n"); | |
706 | printk("turning off the locking correctness validator.\n"); | |
707 | dump_stack(); | |
708 | ||
709 | return NULL; | |
710 | } | |
711 | ||
712 | key = lock->key->subkeys + subclass; | |
713 | hash_head = classhashentry(key); | |
714 | ||
715 | raw_local_irq_save(flags); | |
716 | if (!graph_lock()) { | |
717 | raw_local_irq_restore(flags); | |
718 | return NULL; | |
719 | } | |
720 | /* | |
721 | * We have to do the hash-walk again, to avoid races | |
722 | * with another CPU: | |
723 | */ | |
724 | list_for_each_entry(class, hash_head, hash_entry) | |
725 | if (class->key == key) | |
726 | goto out_unlock_set; | |
727 | /* | |
728 | * Allocate a new key from the static array, and add it to | |
729 | * the hash: | |
730 | */ | |
731 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
732 | if (!debug_locks_off_graph_unlock()) { | |
733 | raw_local_irq_restore(flags); | |
734 | return NULL; | |
735 | } | |
736 | raw_local_irq_restore(flags); | |
737 | ||
738 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
739 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 740 | dump_stack(); |
8e18257d PZ |
741 | return NULL; |
742 | } | |
743 | class = lock_classes + nr_lock_classes++; | |
744 | debug_atomic_inc(&nr_unused_locks); | |
745 | class->key = key; | |
746 | class->name = lock->name; | |
747 | class->subclass = subclass; | |
748 | INIT_LIST_HEAD(&class->lock_entry); | |
749 | INIT_LIST_HEAD(&class->locks_before); | |
750 | INIT_LIST_HEAD(&class->locks_after); | |
751 | class->name_version = count_matching_names(class); | |
752 | /* | |
753 | * We use RCU's safe list-add method to make | |
754 | * parallel walking of the hash-list safe: | |
755 | */ | |
756 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
757 | /* |
758 | * Add it to the global list of classes: | |
759 | */ | |
760 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
761 | |
762 | if (verbose(class)) { | |
763 | graph_unlock(); | |
764 | raw_local_irq_restore(flags); | |
765 | ||
766 | printk("\nnew class %p: %s", class->key, class->name); | |
767 | if (class->name_version > 1) | |
768 | printk("#%d", class->name_version); | |
769 | printk("\n"); | |
770 | dump_stack(); | |
771 | ||
772 | raw_local_irq_save(flags); | |
773 | if (!graph_lock()) { | |
774 | raw_local_irq_restore(flags); | |
775 | return NULL; | |
776 | } | |
777 | } | |
778 | out_unlock_set: | |
779 | graph_unlock(); | |
780 | raw_local_irq_restore(flags); | |
781 | ||
782 | if (!subclass || force) | |
783 | lock->class_cache = class; | |
784 | ||
785 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
786 | return NULL; | |
787 | ||
788 | return class; | |
789 | } | |
790 | ||
791 | #ifdef CONFIG_PROVE_LOCKING | |
792 | /* | |
793 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
794 | * with NULL on failure) | |
795 | */ | |
796 | static struct lock_list *alloc_list_entry(void) | |
797 | { | |
798 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
799 | if (!debug_locks_off_graph_unlock()) | |
800 | return NULL; | |
801 | ||
802 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
803 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 804 | dump_stack(); |
8e18257d PZ |
805 | return NULL; |
806 | } | |
807 | return list_entries + nr_list_entries++; | |
808 | } | |
809 | ||
810 | /* | |
811 | * Add a new dependency to the head of the list: | |
812 | */ | |
813 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
814 | struct list_head *head, unsigned long ip, int distance) | |
815 | { | |
816 | struct lock_list *entry; | |
817 | /* | |
818 | * Lock not present yet - get a new dependency struct and | |
819 | * add it to the list: | |
820 | */ | |
821 | entry = alloc_list_entry(); | |
822 | if (!entry) | |
823 | return 0; | |
824 | ||
8e18257d PZ |
825 | if (!save_trace(&entry->trace)) |
826 | return 0; | |
827 | ||
74870172 ZY |
828 | entry->class = this; |
829 | entry->distance = distance; | |
8e18257d PZ |
830 | /* |
831 | * Since we never remove from the dependency list, the list can | |
832 | * be walked lockless by other CPUs, it's only allocation | |
833 | * that must be protected by the spinlock. But this also means | |
834 | * we must make new entries visible only once writes to the | |
835 | * entry become visible - hence the RCU op: | |
836 | */ | |
837 | list_add_tail_rcu(&entry->entry, head); | |
838 | ||
839 | return 1; | |
840 | } | |
841 | ||
98c33edd PZ |
842 | /* |
843 | * For good efficiency of modular, we use power of 2 | |
844 | */ | |
af012961 PZ |
845 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
846 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
847 | ||
98c33edd PZ |
848 | /* |
849 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
850 | * breadth-first search(BFS)algorithem, by which we can build |
851 | * the shortest path from the next lock to be acquired to the | |
852 | * previous held lock if there is a circular between them. | |
98c33edd | 853 | */ |
af012961 PZ |
854 | struct circular_queue { |
855 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
856 | unsigned int front, rear; | |
857 | }; | |
858 | ||
859 | static struct circular_queue lock_cq; | |
af012961 | 860 | |
12f3dfd0 | 861 | unsigned int max_bfs_queue_depth; |
af012961 | 862 | |
e351b660 ML |
863 | static unsigned int lockdep_dependency_gen_id; |
864 | ||
af012961 PZ |
865 | static inline void __cq_init(struct circular_queue *cq) |
866 | { | |
867 | cq->front = cq->rear = 0; | |
e351b660 | 868 | lockdep_dependency_gen_id++; |
af012961 PZ |
869 | } |
870 | ||
871 | static inline int __cq_empty(struct circular_queue *cq) | |
872 | { | |
873 | return (cq->front == cq->rear); | |
874 | } | |
875 | ||
876 | static inline int __cq_full(struct circular_queue *cq) | |
877 | { | |
878 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
879 | } | |
880 | ||
881 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
882 | { | |
883 | if (__cq_full(cq)) | |
884 | return -1; | |
885 | ||
886 | cq->element[cq->rear] = elem; | |
887 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
888 | return 0; | |
889 | } | |
890 | ||
891 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
892 | { | |
893 | if (__cq_empty(cq)) | |
894 | return -1; | |
895 | ||
896 | *elem = cq->element[cq->front]; | |
897 | cq->front = (cq->front + 1) & CQ_MASK; | |
898 | return 0; | |
899 | } | |
900 | ||
901 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
902 | { | |
903 | return (cq->rear - cq->front) & CQ_MASK; | |
904 | } | |
905 | ||
906 | static inline void mark_lock_accessed(struct lock_list *lock, | |
907 | struct lock_list *parent) | |
908 | { | |
909 | unsigned long nr; | |
98c33edd | 910 | |
af012961 PZ |
911 | nr = lock - list_entries; |
912 | WARN_ON(nr >= nr_list_entries); | |
913 | lock->parent = parent; | |
e351b660 | 914 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
915 | } |
916 | ||
917 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
918 | { | |
919 | unsigned long nr; | |
98c33edd | 920 | |
af012961 PZ |
921 | nr = lock - list_entries; |
922 | WARN_ON(nr >= nr_list_entries); | |
e351b660 | 923 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
924 | } |
925 | ||
926 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
927 | { | |
928 | return child->parent; | |
929 | } | |
930 | ||
931 | static inline int get_lock_depth(struct lock_list *child) | |
932 | { | |
933 | int depth = 0; | |
934 | struct lock_list *parent; | |
935 | ||
936 | while ((parent = get_lock_parent(child))) { | |
937 | child = parent; | |
938 | depth++; | |
939 | } | |
940 | return depth; | |
941 | } | |
942 | ||
9e2d551e | 943 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
944 | void *data, |
945 | int (*match)(struct lock_list *entry, void *data), | |
946 | struct lock_list **target_entry, | |
947 | int forward) | |
c94aa5ca ML |
948 | { |
949 | struct lock_list *entry; | |
d588e461 | 950 | struct list_head *head; |
c94aa5ca ML |
951 | struct circular_queue *cq = &lock_cq; |
952 | int ret = 1; | |
953 | ||
9e2d551e | 954 | if (match(source_entry, data)) { |
c94aa5ca ML |
955 | *target_entry = source_entry; |
956 | ret = 0; | |
957 | goto exit; | |
958 | } | |
959 | ||
d588e461 ML |
960 | if (forward) |
961 | head = &source_entry->class->locks_after; | |
962 | else | |
963 | head = &source_entry->class->locks_before; | |
964 | ||
965 | if (list_empty(head)) | |
966 | goto exit; | |
967 | ||
968 | __cq_init(cq); | |
c94aa5ca ML |
969 | __cq_enqueue(cq, (unsigned long)source_entry); |
970 | ||
971 | while (!__cq_empty(cq)) { | |
972 | struct lock_list *lock; | |
c94aa5ca ML |
973 | |
974 | __cq_dequeue(cq, (unsigned long *)&lock); | |
975 | ||
976 | if (!lock->class) { | |
977 | ret = -2; | |
978 | goto exit; | |
979 | } | |
980 | ||
981 | if (forward) | |
982 | head = &lock->class->locks_after; | |
983 | else | |
984 | head = &lock->class->locks_before; | |
985 | ||
986 | list_for_each_entry(entry, head, entry) { | |
987 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 988 | unsigned int cq_depth; |
c94aa5ca | 989 | mark_lock_accessed(entry, lock); |
9e2d551e | 990 | if (match(entry, data)) { |
c94aa5ca ML |
991 | *target_entry = entry; |
992 | ret = 0; | |
993 | goto exit; | |
994 | } | |
995 | ||
996 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
997 | ret = -1; | |
998 | goto exit; | |
999 | } | |
12f3dfd0 ML |
1000 | cq_depth = __cq_get_elem_count(cq); |
1001 | if (max_bfs_queue_depth < cq_depth) | |
1002 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1003 | } |
1004 | } | |
1005 | } | |
1006 | exit: | |
1007 | return ret; | |
1008 | } | |
1009 | ||
d7aaba14 | 1010 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1011 | void *data, |
1012 | int (*match)(struct lock_list *entry, void *data), | |
1013 | struct lock_list **target_entry) | |
c94aa5ca | 1014 | { |
9e2d551e | 1015 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1016 | |
1017 | } | |
1018 | ||
d7aaba14 | 1019 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1020 | void *data, |
1021 | int (*match)(struct lock_list *entry, void *data), | |
1022 | struct lock_list **target_entry) | |
c94aa5ca | 1023 | { |
9e2d551e | 1024 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1025 | |
1026 | } | |
1027 | ||
8e18257d PZ |
1028 | /* |
1029 | * Recursive, forwards-direction lock-dependency checking, used for | |
1030 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1031 | * checking. | |
8e18257d | 1032 | */ |
8e18257d PZ |
1033 | |
1034 | /* | |
1035 | * Print a dependency chain entry (this is only done when a deadlock | |
1036 | * has been detected): | |
1037 | */ | |
1038 | static noinline int | |
24208ca7 | 1039 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1040 | { |
1041 | if (debug_locks_silent) | |
1042 | return 0; | |
1043 | printk("\n-> #%u", depth); | |
1044 | print_lock_name(target->class); | |
1045 | printk(":\n"); | |
1046 | print_stack_trace(&target->trace, 6); | |
1047 | ||
1048 | return 0; | |
1049 | } | |
1050 | ||
1051 | /* | |
1052 | * When a circular dependency is detected, print the | |
1053 | * header first: | |
1054 | */ | |
1055 | static noinline int | |
db0002a3 ML |
1056 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1057 | struct held_lock *check_src, | |
1058 | struct held_lock *check_tgt) | |
8e18257d PZ |
1059 | { |
1060 | struct task_struct *curr = current; | |
1061 | ||
c94aa5ca | 1062 | if (debug_locks_silent) |
8e18257d PZ |
1063 | return 0; |
1064 | ||
1065 | printk("\n=======================================================\n"); | |
1066 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1067 | print_kernel_version(); | |
1068 | printk( "-------------------------------------------------------\n"); | |
1069 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1070 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1071 | print_lock(check_src); |
8e18257d | 1072 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1073 | print_lock(check_tgt); |
8e18257d PZ |
1074 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1075 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1076 | ||
1077 | print_circular_bug_entry(entry, depth); | |
1078 | ||
1079 | return 0; | |
1080 | } | |
1081 | ||
9e2d551e ML |
1082 | static inline int class_equal(struct lock_list *entry, void *data) |
1083 | { | |
1084 | return entry->class == data; | |
1085 | } | |
1086 | ||
db0002a3 ML |
1087 | static noinline int print_circular_bug(struct lock_list *this, |
1088 | struct lock_list *target, | |
1089 | struct held_lock *check_src, | |
1090 | struct held_lock *check_tgt) | |
8e18257d PZ |
1091 | { |
1092 | struct task_struct *curr = current; | |
c94aa5ca | 1093 | struct lock_list *parent; |
24208ca7 | 1094 | int depth; |
8e18257d | 1095 | |
c94aa5ca | 1096 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1097 | return 0; |
1098 | ||
db0002a3 | 1099 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1100 | return 0; |
1101 | ||
c94aa5ca ML |
1102 | depth = get_lock_depth(target); |
1103 | ||
db0002a3 | 1104 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1105 | |
1106 | parent = get_lock_parent(target); | |
1107 | ||
1108 | while (parent) { | |
1109 | print_circular_bug_entry(parent, --depth); | |
1110 | parent = get_lock_parent(parent); | |
1111 | } | |
8e18257d PZ |
1112 | |
1113 | printk("\nother info that might help us debug this:\n\n"); | |
1114 | lockdep_print_held_locks(curr); | |
1115 | ||
1116 | printk("\nstack backtrace:\n"); | |
1117 | dump_stack(); | |
1118 | ||
1119 | return 0; | |
1120 | } | |
1121 | ||
db0002a3 ML |
1122 | static noinline int print_bfs_bug(int ret) |
1123 | { | |
1124 | if (!debug_locks_off_graph_unlock()) | |
1125 | return 0; | |
1126 | ||
1127 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1128 | ||
1129 | return 0; | |
1130 | } | |
1131 | ||
ef681026 | 1132 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1133 | { |
ef681026 ML |
1134 | (*(unsigned long *)data)++; |
1135 | return 0; | |
1136 | } | |
419ca3f1 | 1137 | |
ef681026 ML |
1138 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1139 | { | |
1140 | unsigned long count = 0; | |
1141 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1142 | |
ef681026 | 1143 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1144 | |
ef681026 | 1145 | return count; |
419ca3f1 | 1146 | } |
419ca3f1 DM |
1147 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1148 | { | |
1149 | unsigned long ret, flags; | |
ef681026 ML |
1150 | struct lock_list this; |
1151 | ||
1152 | this.parent = NULL; | |
1153 | this.class = class; | |
419ca3f1 DM |
1154 | |
1155 | local_irq_save(flags); | |
1156 | __raw_spin_lock(&lockdep_lock); | |
ef681026 | 1157 | ret = __lockdep_count_forward_deps(&this); |
419ca3f1 DM |
1158 | __raw_spin_unlock(&lockdep_lock); |
1159 | local_irq_restore(flags); | |
1160 | ||
1161 | return ret; | |
1162 | } | |
1163 | ||
ef681026 | 1164 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1165 | { |
ef681026 ML |
1166 | unsigned long count = 0; |
1167 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1168 | |
ef681026 | 1169 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1170 | |
ef681026 | 1171 | return count; |
419ca3f1 DM |
1172 | } |
1173 | ||
1174 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1175 | { | |
1176 | unsigned long ret, flags; | |
ef681026 ML |
1177 | struct lock_list this; |
1178 | ||
1179 | this.parent = NULL; | |
1180 | this.class = class; | |
419ca3f1 DM |
1181 | |
1182 | local_irq_save(flags); | |
1183 | __raw_spin_lock(&lockdep_lock); | |
ef681026 | 1184 | ret = __lockdep_count_backward_deps(&this); |
419ca3f1 DM |
1185 | __raw_spin_unlock(&lockdep_lock); |
1186 | local_irq_restore(flags); | |
1187 | ||
1188 | return ret; | |
1189 | } | |
1190 | ||
8e18257d PZ |
1191 | /* |
1192 | * Prove that the dependency graph starting at <entry> can not | |
1193 | * lead to <target>. Print an error and return 0 if it does. | |
1194 | */ | |
1195 | static noinline int | |
db0002a3 ML |
1196 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1197 | struct lock_list **target_entry) | |
8e18257d | 1198 | { |
db0002a3 | 1199 | int result; |
8e18257d | 1200 | |
db0002a3 | 1201 | debug_atomic_inc(&nr_cyclic_checks); |
419ca3f1 | 1202 | |
d7aaba14 | 1203 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1204 | |
db0002a3 ML |
1205 | return result; |
1206 | } | |
c94aa5ca | 1207 | |
81d68a96 | 1208 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1209 | /* |
1210 | * Forwards and backwards subgraph searching, for the purposes of | |
1211 | * proving that two subgraphs can be connected by a new dependency | |
1212 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1213 | */ | |
fbb9ce95 | 1214 | |
d7aaba14 ML |
1215 | static inline int usage_match(struct lock_list *entry, void *bit) |
1216 | { | |
1217 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1218 | } | |
1219 | ||
1220 | ||
1221 | ||
fbb9ce95 IM |
1222 | /* |
1223 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1224 | * at @root->class that matches @bit. |
fbb9ce95 | 1225 | * |
d7aaba14 ML |
1226 | * Return 0 if such a node exists in the subgraph, and put that node |
1227 | * into *@target_entry. | |
fbb9ce95 | 1228 | * |
d7aaba14 ML |
1229 | * Return 1 otherwise and keep *@target_entry unchanged. |
1230 | * Return <0 on error. | |
fbb9ce95 | 1231 | */ |
d7aaba14 ML |
1232 | static int |
1233 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1234 | struct lock_list **target_entry) | |
fbb9ce95 | 1235 | { |
d7aaba14 | 1236 | int result; |
fbb9ce95 IM |
1237 | |
1238 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
fbb9ce95 | 1239 | |
d7aaba14 ML |
1240 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1241 | ||
1242 | return result; | |
fbb9ce95 IM |
1243 | } |
1244 | ||
1245 | /* | |
1246 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1247 | * at @root->class that matches @bit. |
fbb9ce95 | 1248 | * |
d7aaba14 ML |
1249 | * Return 0 if such a node exists in the subgraph, and put that node |
1250 | * into *@target_entry. | |
fbb9ce95 | 1251 | * |
d7aaba14 ML |
1252 | * Return 1 otherwise and keep *@target_entry unchanged. |
1253 | * Return <0 on error. | |
fbb9ce95 | 1254 | */ |
d7aaba14 ML |
1255 | static int |
1256 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1257 | struct lock_list **target_entry) | |
fbb9ce95 | 1258 | { |
d7aaba14 | 1259 | int result; |
fbb9ce95 IM |
1260 | |
1261 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
fbb9ce95 | 1262 | |
d7aaba14 | 1263 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1264 | |
d7aaba14 | 1265 | return result; |
fbb9ce95 IM |
1266 | } |
1267 | ||
af012961 PZ |
1268 | static void print_lock_class_header(struct lock_class *class, int depth) |
1269 | { | |
1270 | int bit; | |
1271 | ||
1272 | printk("%*s->", depth, ""); | |
1273 | print_lock_name(class); | |
1274 | printk(" ops: %lu", class->ops); | |
1275 | printk(" {\n"); | |
1276 | ||
1277 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1278 | if (class->usage_mask & (1 << bit)) { | |
1279 | int len = depth; | |
1280 | ||
1281 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1282 | len += printk(" at:\n"); | |
1283 | print_stack_trace(class->usage_traces + bit, len); | |
1284 | } | |
1285 | } | |
1286 | printk("%*s }\n", depth, ""); | |
1287 | ||
1288 | printk("%*s ... key at: ",depth,""); | |
1289 | print_ip_sym((unsigned long)class->key); | |
1290 | } | |
1291 | ||
1292 | /* | |
1293 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1294 | */ | |
1295 | static void __used | |
1296 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1297 | struct lock_list *root) | |
1298 | { | |
1299 | struct lock_list *entry = leaf; | |
1300 | int depth; | |
1301 | ||
1302 | /*compute depth from generated tree by BFS*/ | |
1303 | depth = get_lock_depth(leaf); | |
1304 | ||
1305 | do { | |
1306 | print_lock_class_header(entry->class, depth); | |
1307 | printk("%*s ... acquired at:\n", depth, ""); | |
1308 | print_stack_trace(&entry->trace, 2); | |
1309 | printk("\n"); | |
1310 | ||
1311 | if (depth == 0 && (entry != root)) { | |
1312 | printk("lockdep:%s bad BFS generated tree\n", __func__); | |
1313 | break; | |
1314 | } | |
1315 | ||
1316 | entry = get_lock_parent(entry); | |
1317 | depth--; | |
1318 | } while (entry && (depth >= 0)); | |
1319 | ||
1320 | return; | |
1321 | } | |
d7aaba14 | 1322 | |
fbb9ce95 IM |
1323 | static int |
1324 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1325 | struct lock_list *prev_root, |
1326 | struct lock_list *next_root, | |
1327 | struct lock_list *backwards_entry, | |
1328 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1329 | struct held_lock *prev, |
1330 | struct held_lock *next, | |
1331 | enum lock_usage_bit bit1, | |
1332 | enum lock_usage_bit bit2, | |
1333 | const char *irqclass) | |
1334 | { | |
74c383f1 | 1335 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1336 | return 0; |
1337 | ||
1338 | printk("\n======================================================\n"); | |
1339 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1340 | irqclass, irqclass); | |
99de055a | 1341 | print_kernel_version(); |
fbb9ce95 IM |
1342 | printk( "------------------------------------------------------\n"); |
1343 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1344 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1345 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1346 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1347 | curr->hardirqs_enabled, | |
1348 | curr->softirqs_enabled); | |
1349 | print_lock(next); | |
1350 | ||
1351 | printk("\nand this task is already holding:\n"); | |
1352 | print_lock(prev); | |
1353 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1354 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1355 | printk(" ->"); |
f82b217e | 1356 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1357 | printk("\n"); |
1358 | ||
1359 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1360 | irqclass); | |
24208ca7 | 1361 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1362 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1363 | ||
24208ca7 | 1364 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1365 | |
1366 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1367 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1368 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1369 | printk("..."); | |
1370 | ||
24208ca7 | 1371 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1372 | |
1373 | printk("\nother info that might help us debug this:\n\n"); | |
1374 | lockdep_print_held_locks(curr); | |
1375 | ||
24208ca7 ML |
1376 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1377 | printk(" and the holding lock:\n"); | |
1378 | if (!save_trace(&prev_root->trace)) | |
1379 | return 0; | |
1380 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1381 | |
24208ca7 ML |
1382 | printk("\nthe dependencies between the lock to be acquired"); |
1383 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1384 | if (!save_trace(&next_root->trace)) | |
1385 | return 0; | |
1386 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1387 | |
1388 | printk("\nstack backtrace:\n"); | |
1389 | dump_stack(); | |
1390 | ||
1391 | return 0; | |
1392 | } | |
1393 | ||
1394 | static int | |
1395 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1396 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1397 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1398 | { | |
1399 | int ret; | |
24208ca7 | 1400 | struct lock_list this, that; |
d7aaba14 | 1401 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1402 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1403 | |
1404 | this.parent = NULL; | |
1405 | ||
1406 | this.class = hlock_class(prev); | |
1407 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1408 | if (ret < 0) |
1409 | return print_bfs_bug(ret); | |
1410 | if (ret == 1) | |
1411 | return ret; | |
d7aaba14 | 1412 | |
24208ca7 ML |
1413 | that.parent = NULL; |
1414 | that.class = hlock_class(next); | |
1415 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1416 | if (ret < 0) |
1417 | return print_bfs_bug(ret); | |
1418 | if (ret == 1) | |
1419 | return ret; | |
fbb9ce95 | 1420 | |
24208ca7 ML |
1421 | return print_bad_irq_dependency(curr, &this, &that, |
1422 | target_entry, target_entry1, | |
1423 | prev, next, | |
fbb9ce95 IM |
1424 | bit_backwards, bit_forwards, irqclass); |
1425 | } | |
1426 | ||
4f367d8a PZ |
1427 | static const char *state_names[] = { |
1428 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1429 | __stringify(__STATE), |
4f367d8a PZ |
1430 | #include "lockdep_states.h" |
1431 | #undef LOCKDEP_STATE | |
1432 | }; | |
1433 | ||
1434 | static const char *state_rnames[] = { | |
1435 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1436 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1437 | #include "lockdep_states.h" |
1438 | #undef LOCKDEP_STATE | |
1439 | }; | |
1440 | ||
1441 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1442 | { |
4f367d8a PZ |
1443 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1444 | } | |
8e18257d | 1445 | |
4f367d8a PZ |
1446 | static int exclusive_bit(int new_bit) |
1447 | { | |
8e18257d | 1448 | /* |
4f367d8a PZ |
1449 | * USED_IN |
1450 | * USED_IN_READ | |
1451 | * ENABLED | |
1452 | * ENABLED_READ | |
1453 | * | |
1454 | * bit 0 - write/read | |
1455 | * bit 1 - used_in/enabled | |
1456 | * bit 2+ state | |
8e18257d | 1457 | */ |
4f367d8a PZ |
1458 | |
1459 | int state = new_bit & ~3; | |
1460 | int dir = new_bit & 2; | |
8e18257d PZ |
1461 | |
1462 | /* | |
4f367d8a | 1463 | * keep state, bit flip the direction and strip read. |
8e18257d | 1464 | */ |
4f367d8a PZ |
1465 | return state | (dir ^ 2); |
1466 | } | |
1467 | ||
1468 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1469 | struct held_lock *next, enum lock_usage_bit bit) | |
1470 | { | |
8e18257d | 1471 | /* |
4f367d8a PZ |
1472 | * Prove that the new dependency does not connect a hardirq-safe |
1473 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1474 | * the backwards-subgraph starting at <prev>, and the |
1475 | * forwards-subgraph starting at <next>: | |
1476 | */ | |
4f367d8a PZ |
1477 | if (!check_usage(curr, prev, next, bit, |
1478 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1479 | return 0; |
1480 | ||
4f367d8a PZ |
1481 | bit++; /* _READ */ |
1482 | ||
cf40bd16 | 1483 | /* |
4f367d8a PZ |
1484 | * Prove that the new dependency does not connect a hardirq-safe-read |
1485 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1486 | * the backwards-subgraph starting at <prev>, and the |
1487 | * forwards-subgraph starting at <next>: | |
1488 | */ | |
4f367d8a PZ |
1489 | if (!check_usage(curr, prev, next, bit, |
1490 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1491 | return 0; |
1492 | ||
4f367d8a PZ |
1493 | return 1; |
1494 | } | |
1495 | ||
1496 | static int | |
1497 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1498 | struct held_lock *next) | |
1499 | { | |
1500 | #define LOCKDEP_STATE(__STATE) \ | |
1501 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1502 | return 0; |
4f367d8a PZ |
1503 | #include "lockdep_states.h" |
1504 | #undef LOCKDEP_STATE | |
cf40bd16 | 1505 | |
8e18257d PZ |
1506 | return 1; |
1507 | } | |
1508 | ||
1509 | static void inc_chains(void) | |
1510 | { | |
1511 | if (current->hardirq_context) | |
1512 | nr_hardirq_chains++; | |
1513 | else { | |
1514 | if (current->softirq_context) | |
1515 | nr_softirq_chains++; | |
1516 | else | |
1517 | nr_process_chains++; | |
1518 | } | |
1519 | } | |
1520 | ||
1521 | #else | |
1522 | ||
1523 | static inline int | |
1524 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1525 | struct held_lock *next) | |
1526 | { | |
1527 | return 1; | |
1528 | } | |
1529 | ||
1530 | static inline void inc_chains(void) | |
1531 | { | |
1532 | nr_process_chains++; | |
1533 | } | |
1534 | ||
fbb9ce95 IM |
1535 | #endif |
1536 | ||
1537 | static int | |
1538 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1539 | struct held_lock *next) | |
1540 | { | |
74c383f1 | 1541 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1542 | return 0; |
1543 | ||
1544 | printk("\n=============================================\n"); | |
1545 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1546 | print_kernel_version(); |
fbb9ce95 IM |
1547 | printk( "---------------------------------------------\n"); |
1548 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1549 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1550 | print_lock(next); |
1551 | printk("\nbut task is already holding lock:\n"); | |
1552 | print_lock(prev); | |
1553 | ||
1554 | printk("\nother info that might help us debug this:\n"); | |
1555 | lockdep_print_held_locks(curr); | |
1556 | ||
1557 | printk("\nstack backtrace:\n"); | |
1558 | dump_stack(); | |
1559 | ||
1560 | return 0; | |
1561 | } | |
1562 | ||
1563 | /* | |
1564 | * Check whether we are holding such a class already. | |
1565 | * | |
1566 | * (Note that this has to be done separately, because the graph cannot | |
1567 | * detect such classes of deadlocks.) | |
1568 | * | |
1569 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1570 | */ | |
1571 | static int | |
1572 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1573 | struct lockdep_map *next_instance, int read) | |
1574 | { | |
1575 | struct held_lock *prev; | |
7531e2f3 | 1576 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1577 | int i; |
1578 | ||
1579 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1580 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1581 | |
1582 | if (prev->instance == next->nest_lock) | |
1583 | nest = prev; | |
1584 | ||
f82b217e | 1585 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1586 | continue; |
7531e2f3 | 1587 | |
fbb9ce95 IM |
1588 | /* |
1589 | * Allow read-after-read recursion of the same | |
6c9076ec | 1590 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1591 | */ |
6c9076ec | 1592 | if ((read == 2) && prev->read) |
fbb9ce95 | 1593 | return 2; |
7531e2f3 PZ |
1594 | |
1595 | /* | |
1596 | * We're holding the nest_lock, which serializes this lock's | |
1597 | * nesting behaviour. | |
1598 | */ | |
1599 | if (nest) | |
1600 | return 2; | |
1601 | ||
fbb9ce95 IM |
1602 | return print_deadlock_bug(curr, prev, next); |
1603 | } | |
1604 | return 1; | |
1605 | } | |
1606 | ||
1607 | /* | |
1608 | * There was a chain-cache miss, and we are about to add a new dependency | |
1609 | * to a previous lock. We recursively validate the following rules: | |
1610 | * | |
1611 | * - would the adding of the <prev> -> <next> dependency create a | |
1612 | * circular dependency in the graph? [== circular deadlock] | |
1613 | * | |
1614 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1615 | * (in the full backwards-subgraph starting at <prev>) with any | |
1616 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1617 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1618 | * | |
1619 | * - does the new prev->next dependency connect any softirq-safe lock | |
1620 | * (in the full backwards-subgraph starting at <prev>) with any | |
1621 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1622 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1623 | * | |
1624 | * any of these scenarios could lead to a deadlock. | |
1625 | * | |
1626 | * Then if all the validations pass, we add the forwards and backwards | |
1627 | * dependency. | |
1628 | */ | |
1629 | static int | |
1630 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1631 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1632 | { |
1633 | struct lock_list *entry; | |
1634 | int ret; | |
db0002a3 ML |
1635 | struct lock_list this; |
1636 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 IM |
1637 | |
1638 | /* | |
1639 | * Prove that the new <prev> -> <next> dependency would not | |
1640 | * create a circular dependency in the graph. (We do this by | |
1641 | * forward-recursing into the graph starting at <next>, and | |
1642 | * checking whether we can reach <prev>.) | |
1643 | * | |
1644 | * We are using global variables to control the recursion, to | |
1645 | * keep the stackframe size of the recursive functions low: | |
1646 | */ | |
db0002a3 ML |
1647 | this.class = hlock_class(next); |
1648 | this.parent = NULL; | |
1649 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1650 | if (unlikely(!ret)) | |
1651 | return print_circular_bug(&this, target_entry, next, prev); | |
1652 | else if (unlikely(ret < 0)) | |
1653 | return print_bfs_bug(ret); | |
c94aa5ca | 1654 | |
8e18257d | 1655 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1656 | return 0; |
1657 | ||
fbb9ce95 IM |
1658 | /* |
1659 | * For recursive read-locks we do all the dependency checks, | |
1660 | * but we dont store read-triggered dependencies (only | |
1661 | * write-triggered dependencies). This ensures that only the | |
1662 | * write-side dependencies matter, and that if for example a | |
1663 | * write-lock never takes any other locks, then the reads are | |
1664 | * equivalent to a NOP. | |
1665 | */ | |
1666 | if (next->read == 2 || prev->read == 2) | |
1667 | return 1; | |
1668 | /* | |
1669 | * Is the <prev> -> <next> dependency already present? | |
1670 | * | |
1671 | * (this may occur even though this is a new chain: consider | |
1672 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1673 | * chains - the second one will be new, but L1 already has | |
1674 | * L2 added to its dependency list, due to the first chain.) | |
1675 | */ | |
f82b217e DJ |
1676 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1677 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1678 | if (distance == 1) |
1679 | entry->distance = 1; | |
fbb9ce95 | 1680 | return 2; |
068135e6 | 1681 | } |
fbb9ce95 IM |
1682 | } |
1683 | ||
1684 | /* | |
1685 | * Ok, all validations passed, add the new lock | |
1686 | * to the previous lock's dependency list: | |
1687 | */ | |
f82b217e DJ |
1688 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1689 | &hlock_class(prev)->locks_after, | |
1690 | next->acquire_ip, distance); | |
068135e6 | 1691 | |
fbb9ce95 IM |
1692 | if (!ret) |
1693 | return 0; | |
910b1b2e | 1694 | |
f82b217e DJ |
1695 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1696 | &hlock_class(next)->locks_before, | |
1697 | next->acquire_ip, distance); | |
910b1b2e JP |
1698 | if (!ret) |
1699 | return 0; | |
fbb9ce95 IM |
1700 | |
1701 | /* | |
8e18257d PZ |
1702 | * Debugging printouts: |
1703 | */ | |
f82b217e | 1704 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1705 | graph_unlock(); |
1706 | printk("\n new dependency: "); | |
f82b217e | 1707 | print_lock_name(hlock_class(prev)); |
8e18257d | 1708 | printk(" => "); |
f82b217e | 1709 | print_lock_name(hlock_class(next)); |
8e18257d | 1710 | printk("\n"); |
fbb9ce95 | 1711 | dump_stack(); |
8e18257d | 1712 | return graph_lock(); |
fbb9ce95 | 1713 | } |
8e18257d PZ |
1714 | return 1; |
1715 | } | |
fbb9ce95 | 1716 | |
8e18257d PZ |
1717 | /* |
1718 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1719 | * The ones that are relevant are (in increasing distance from curr): | |
1720 | * all consecutive trylock entries and the final non-trylock entry - or | |
1721 | * the end of this context's lock-chain - whichever comes first. | |
1722 | */ | |
1723 | static int | |
1724 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1725 | { | |
1726 | int depth = curr->lockdep_depth; | |
1727 | struct held_lock *hlock; | |
d6d897ce | 1728 | |
fbb9ce95 | 1729 | /* |
8e18257d PZ |
1730 | * Debugging checks. |
1731 | * | |
1732 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1733 | */ |
8e18257d PZ |
1734 | if (!depth) |
1735 | goto out_bug; | |
fbb9ce95 | 1736 | /* |
8e18257d PZ |
1737 | * At least two relevant locks must exist for this |
1738 | * to be a head: | |
fbb9ce95 | 1739 | */ |
8e18257d PZ |
1740 | if (curr->held_locks[depth].irq_context != |
1741 | curr->held_locks[depth-1].irq_context) | |
1742 | goto out_bug; | |
74c383f1 | 1743 | |
8e18257d PZ |
1744 | for (;;) { |
1745 | int distance = curr->lockdep_depth - depth + 1; | |
1746 | hlock = curr->held_locks + depth-1; | |
1747 | /* | |
1748 | * Only non-recursive-read entries get new dependencies | |
1749 | * added: | |
1750 | */ | |
1751 | if (hlock->read != 2) { | |
1752 | if (!check_prev_add(curr, hlock, next, distance)) | |
1753 | return 0; | |
1754 | /* | |
1755 | * Stop after the first non-trylock entry, | |
1756 | * as non-trylock entries have added their | |
1757 | * own direct dependencies already, so this | |
1758 | * lock is connected to them indirectly: | |
1759 | */ | |
1760 | if (!hlock->trylock) | |
1761 | break; | |
74c383f1 | 1762 | } |
8e18257d PZ |
1763 | depth--; |
1764 | /* | |
1765 | * End of lock-stack? | |
1766 | */ | |
1767 | if (!depth) | |
1768 | break; | |
1769 | /* | |
1770 | * Stop the search if we cross into another context: | |
1771 | */ | |
1772 | if (curr->held_locks[depth].irq_context != | |
1773 | curr->held_locks[depth-1].irq_context) | |
1774 | break; | |
fbb9ce95 | 1775 | } |
8e18257d PZ |
1776 | return 1; |
1777 | out_bug: | |
1778 | if (!debug_locks_off_graph_unlock()) | |
1779 | return 0; | |
fbb9ce95 | 1780 | |
8e18257d | 1781 | WARN_ON(1); |
fbb9ce95 | 1782 | |
8e18257d | 1783 | return 0; |
fbb9ce95 IM |
1784 | } |
1785 | ||
8e18257d | 1786 | unsigned long nr_lock_chains; |
443cd507 | 1787 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1788 | int nr_chain_hlocks; |
443cd507 HY |
1789 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1790 | ||
1791 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1792 | { | |
1793 | return lock_classes + chain_hlocks[chain->base + i]; | |
1794 | } | |
8e18257d | 1795 | |
fbb9ce95 IM |
1796 | /* |
1797 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1798 | * add it and return 1 - in this case the new dependency chain is |
1799 | * validated. If the key is already hashed, return 0. | |
1800 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1801 | */ |
443cd507 HY |
1802 | static inline int lookup_chain_cache(struct task_struct *curr, |
1803 | struct held_lock *hlock, | |
1804 | u64 chain_key) | |
fbb9ce95 | 1805 | { |
f82b217e | 1806 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1807 | struct list_head *hash_head = chainhashentry(chain_key); |
1808 | struct lock_chain *chain; | |
443cd507 | 1809 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1810 | int i, j, n, cn; |
fbb9ce95 | 1811 | |
381a2292 JP |
1812 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1813 | return 0; | |
fbb9ce95 IM |
1814 | /* |
1815 | * We can walk it lock-free, because entries only get added | |
1816 | * to the hash: | |
1817 | */ | |
1818 | list_for_each_entry(chain, hash_head, entry) { | |
1819 | if (chain->chain_key == chain_key) { | |
1820 | cache_hit: | |
1821 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1822 | if (very_verbose(class)) |
755cd900 AM |
1823 | printk("\nhash chain already cached, key: " |
1824 | "%016Lx tail class: [%p] %s\n", | |
1825 | (unsigned long long)chain_key, | |
1826 | class->key, class->name); | |
fbb9ce95 IM |
1827 | return 0; |
1828 | } | |
1829 | } | |
81fc685a | 1830 | if (very_verbose(class)) |
755cd900 AM |
1831 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1832 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1833 | /* |
1834 | * Allocate a new chain entry from the static array, and add | |
1835 | * it to the hash: | |
1836 | */ | |
74c383f1 IM |
1837 | if (!graph_lock()) |
1838 | return 0; | |
fbb9ce95 IM |
1839 | /* |
1840 | * We have to walk the chain again locked - to avoid duplicates: | |
1841 | */ | |
1842 | list_for_each_entry(chain, hash_head, entry) { | |
1843 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1844 | graph_unlock(); |
fbb9ce95 IM |
1845 | goto cache_hit; |
1846 | } | |
1847 | } | |
1848 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1849 | if (!debug_locks_off_graph_unlock()) |
1850 | return 0; | |
1851 | ||
fbb9ce95 IM |
1852 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1853 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 1854 | dump_stack(); |
fbb9ce95 IM |
1855 | return 0; |
1856 | } | |
1857 | chain = lock_chains + nr_lock_chains++; | |
1858 | chain->chain_key = chain_key; | |
443cd507 HY |
1859 | chain->irq_context = hlock->irq_context; |
1860 | /* Find the first held_lock of current chain */ | |
1861 | hlock_next = hlock; | |
1862 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1863 | hlock_curr = curr->held_locks + i; | |
1864 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1865 | break; | |
1866 | hlock_next = hlock; | |
1867 | } | |
1868 | i++; | |
1869 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1870 | cn = nr_chain_hlocks; |
1871 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1872 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1873 | if (n == cn) | |
1874 | break; | |
1875 | cn = n; | |
1876 | } | |
1877 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1878 | chain->base = cn; | |
443cd507 | 1879 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1880 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1881 | chain_hlocks[chain->base + j] = lock_id; |
1882 | } | |
1883 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1884 | } | |
fbb9ce95 IM |
1885 | list_add_tail_rcu(&chain->entry, hash_head); |
1886 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1887 | inc_chains(); |
1888 | ||
1889 | return 1; | |
1890 | } | |
1891 | ||
1892 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1893 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1894 | { |
1895 | /* | |
1896 | * Trylock needs to maintain the stack of held locks, but it | |
1897 | * does not add new dependencies, because trylock can be done | |
1898 | * in any order. | |
1899 | * | |
1900 | * We look up the chain_key and do the O(N^2) check and update of | |
1901 | * the dependencies only if this is a new dependency chain. | |
1902 | * (If lookup_chain_cache() returns with 1 it acquires | |
1903 | * graph_lock for us) | |
1904 | */ | |
1905 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1906 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1907 | /* |
1908 | * Check whether last held lock: | |
1909 | * | |
1910 | * - is irq-safe, if this lock is irq-unsafe | |
1911 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1912 | * | |
1913 | * And check whether the new lock's dependency graph | |
1914 | * could lead back to the previous lock. | |
1915 | * | |
1916 | * any of these scenarios could lead to a deadlock. If | |
1917 | * All validations | |
1918 | */ | |
1919 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1920 | ||
1921 | if (!ret) | |
1922 | return 0; | |
1923 | /* | |
1924 | * Mark recursive read, as we jump over it when | |
1925 | * building dependencies (just like we jump over | |
1926 | * trylock entries): | |
1927 | */ | |
1928 | if (ret == 2) | |
1929 | hlock->read = 2; | |
1930 | /* | |
1931 | * Add dependency only if this lock is not the head | |
1932 | * of the chain, and if it's not a secondary read-lock: | |
1933 | */ | |
1934 | if (!chain_head && ret != 2) | |
1935 | if (!check_prevs_add(curr, hlock)) | |
1936 | return 0; | |
1937 | graph_unlock(); | |
1938 | } else | |
1939 | /* after lookup_chain_cache(): */ | |
1940 | if (unlikely(!debug_locks)) | |
1941 | return 0; | |
fbb9ce95 IM |
1942 | |
1943 | return 1; | |
1944 | } | |
8e18257d PZ |
1945 | #else |
1946 | static inline int validate_chain(struct task_struct *curr, | |
1947 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1948 | int chain_head, u64 chain_key) |
8e18257d PZ |
1949 | { |
1950 | return 1; | |
1951 | } | |
ca58abcb | 1952 | #endif |
fbb9ce95 IM |
1953 | |
1954 | /* | |
1955 | * We are building curr_chain_key incrementally, so double-check | |
1956 | * it from scratch, to make sure that it's done correctly: | |
1957 | */ | |
1d09daa5 | 1958 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1959 | { |
1960 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1961 | struct held_lock *hlock, *prev_hlock = NULL; | |
1962 | unsigned int i, id; | |
1963 | u64 chain_key = 0; | |
1964 | ||
1965 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1966 | hlock = curr->held_locks + i; | |
1967 | if (chain_key != hlock->prev_chain_key) { | |
1968 | debug_locks_off(); | |
2df8b1d6 | 1969 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1970 | curr->lockdep_depth, i, |
1971 | (unsigned long long)chain_key, | |
1972 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1973 | return; |
1974 | } | |
f82b217e | 1975 | id = hlock->class_idx - 1; |
381a2292 JP |
1976 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1977 | return; | |
1978 | ||
fbb9ce95 IM |
1979 | if (prev_hlock && (prev_hlock->irq_context != |
1980 | hlock->irq_context)) | |
1981 | chain_key = 0; | |
1982 | chain_key = iterate_chain_key(chain_key, id); | |
1983 | prev_hlock = hlock; | |
1984 | } | |
1985 | if (chain_key != curr->curr_chain_key) { | |
1986 | debug_locks_off(); | |
2df8b1d6 | 1987 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1988 | curr->lockdep_depth, i, |
1989 | (unsigned long long)chain_key, | |
1990 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1991 | } |
1992 | #endif | |
1993 | } | |
1994 | ||
8e18257d PZ |
1995 | static int |
1996 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1997 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1998 | { | |
1999 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2000 | return 0; | |
2001 | ||
2002 | printk("\n=================================\n"); | |
2003 | printk( "[ INFO: inconsistent lock state ]\n"); | |
2004 | print_kernel_version(); | |
2005 | printk( "---------------------------------\n"); | |
2006 | ||
2007 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2008 | usage_str[prev_bit], usage_str[new_bit]); | |
2009 | ||
2010 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2011 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2012 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2013 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2014 | trace_hardirqs_enabled(curr), | |
2015 | trace_softirqs_enabled(curr)); | |
2016 | print_lock(this); | |
2017 | ||
2018 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2019 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2020 | |
2021 | print_irqtrace_events(curr); | |
2022 | printk("\nother info that might help us debug this:\n"); | |
2023 | lockdep_print_held_locks(curr); | |
2024 | ||
2025 | printk("\nstack backtrace:\n"); | |
2026 | dump_stack(); | |
2027 | ||
2028 | return 0; | |
2029 | } | |
2030 | ||
2031 | /* | |
2032 | * Print out an error if an invalid bit is set: | |
2033 | */ | |
2034 | static inline int | |
2035 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2036 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2037 | { | |
f82b217e | 2038 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2039 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2040 | return 1; | |
2041 | } | |
2042 | ||
2043 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2044 | enum lock_usage_bit new_bit); | |
2045 | ||
81d68a96 | 2046 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2047 | |
2048 | /* | |
2049 | * print irq inversion bug: | |
2050 | */ | |
2051 | static int | |
24208ca7 ML |
2052 | print_irq_inversion_bug(struct task_struct *curr, |
2053 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2054 | struct held_lock *this, int forwards, |
2055 | const char *irqclass) | |
2056 | { | |
74c383f1 | 2057 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2058 | return 0; |
2059 | ||
2060 | printk("\n=========================================================\n"); | |
2061 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2062 | print_kernel_version(); |
fbb9ce95 IM |
2063 | printk( "---------------------------------------------------------\n"); |
2064 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2065 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2066 | print_lock(this); |
2067 | if (forwards) | |
26575e28 | 2068 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2069 | else |
26575e28 | 2070 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2071 | print_lock_name(other->class); |
fbb9ce95 IM |
2072 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2073 | ||
2074 | printk("\nother info that might help us debug this:\n"); | |
2075 | lockdep_print_held_locks(curr); | |
2076 | ||
24208ca7 ML |
2077 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2078 | if (!save_trace(&root->trace)) | |
2079 | return 0; | |
2080 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2081 | |
2082 | printk("\nstack backtrace:\n"); | |
2083 | dump_stack(); | |
2084 | ||
2085 | return 0; | |
2086 | } | |
2087 | ||
2088 | /* | |
2089 | * Prove that in the forwards-direction subgraph starting at <this> | |
2090 | * there is no lock matching <mask>: | |
2091 | */ | |
2092 | static int | |
2093 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2094 | enum lock_usage_bit bit, const char *irqclass) | |
2095 | { | |
2096 | int ret; | |
d7aaba14 ML |
2097 | struct lock_list root; |
2098 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2099 | |
d7aaba14 ML |
2100 | root.parent = NULL; |
2101 | root.class = hlock_class(this); | |
2102 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2103 | if (ret < 0) |
2104 | return print_bfs_bug(ret); | |
2105 | if (ret == 1) | |
2106 | return ret; | |
fbb9ce95 | 2107 | |
24208ca7 | 2108 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2109 | this, 1, irqclass); |
fbb9ce95 IM |
2110 | } |
2111 | ||
2112 | /* | |
2113 | * Prove that in the backwards-direction subgraph starting at <this> | |
2114 | * there is no lock matching <mask>: | |
2115 | */ | |
2116 | static int | |
2117 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2118 | enum lock_usage_bit bit, const char *irqclass) | |
2119 | { | |
2120 | int ret; | |
d7aaba14 ML |
2121 | struct lock_list root; |
2122 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2123 | |
d7aaba14 ML |
2124 | root.parent = NULL; |
2125 | root.class = hlock_class(this); | |
2126 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2127 | if (ret < 0) |
2128 | return print_bfs_bug(ret); | |
2129 | if (ret == 1) | |
2130 | return ret; | |
fbb9ce95 | 2131 | |
24208ca7 | 2132 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2133 | this, 1, irqclass); |
fbb9ce95 IM |
2134 | } |
2135 | ||
3117df04 | 2136 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2137 | { |
2138 | printk("irq event stamp: %u\n", curr->irq_events); | |
2139 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2140 | print_ip_sym(curr->hardirq_enable_ip); | |
2141 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2142 | print_ip_sym(curr->hardirq_disable_ip); | |
2143 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2144 | print_ip_sym(curr->softirq_enable_ip); | |
2145 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2146 | print_ip_sym(curr->softirq_disable_ip); | |
2147 | } | |
2148 | ||
cd95302d | 2149 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2150 | { |
8e18257d PZ |
2151 | #if HARDIRQ_VERBOSE |
2152 | return class_filter(class); | |
2153 | #endif | |
fbb9ce95 IM |
2154 | return 0; |
2155 | } | |
2156 | ||
cd95302d | 2157 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2158 | { |
8e18257d PZ |
2159 | #if SOFTIRQ_VERBOSE |
2160 | return class_filter(class); | |
2161 | #endif | |
2162 | return 0; | |
fbb9ce95 IM |
2163 | } |
2164 | ||
cd95302d | 2165 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2166 | { |
2167 | #if RECLAIM_VERBOSE | |
2168 | return class_filter(class); | |
2169 | #endif | |
2170 | return 0; | |
2171 | } | |
2172 | ||
fbb9ce95 IM |
2173 | #define STRICT_READ_CHECKS 1 |
2174 | ||
cd95302d PZ |
2175 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2176 | #define LOCKDEP_STATE(__STATE) \ | |
2177 | __STATE##_verbose, | |
2178 | #include "lockdep_states.h" | |
2179 | #undef LOCKDEP_STATE | |
2180 | }; | |
2181 | ||
2182 | static inline int state_verbose(enum lock_usage_bit bit, | |
2183 | struct lock_class *class) | |
2184 | { | |
2185 | return state_verbose_f[bit >> 2](class); | |
2186 | } | |
2187 | ||
42c50d54 PZ |
2188 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2189 | enum lock_usage_bit bit, const char *name); | |
2190 | ||
6a6904d3 | 2191 | static int |
1c21f14e PZ |
2192 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2193 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2194 | { |
f989209e | 2195 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2196 | int read = new_bit & 1; |
42c50d54 PZ |
2197 | int dir = new_bit & 2; |
2198 | ||
38aa2714 PZ |
2199 | /* |
2200 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2201 | * has ENABLED state, which would allow recursion deadlocks. | |
2202 | * | |
2203 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2204 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2205 | */ | |
42c50d54 PZ |
2206 | check_usage_f usage = dir ? |
2207 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2208 | |
38aa2714 PZ |
2209 | /* |
2210 | * Validate that this particular lock does not have conflicting | |
2211 | * usage states. | |
2212 | */ | |
6a6904d3 PZ |
2213 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2214 | return 0; | |
42c50d54 | 2215 | |
38aa2714 PZ |
2216 | /* |
2217 | * Validate that the lock dependencies don't have conflicting usage | |
2218 | * states. | |
2219 | */ | |
2220 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2221 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2222 | return 0; |
780e820b | 2223 | |
38aa2714 PZ |
2224 | /* |
2225 | * Check for read in write conflicts | |
2226 | */ | |
2227 | if (!read) { | |
2228 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2229 | return 0; | |
2230 | ||
2231 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2232 | !usage(curr, this, excl_bit + 1, |
2233 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2234 | return 0; |
2235 | } | |
780e820b | 2236 | |
cd95302d | 2237 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2238 | return 2; |
2239 | ||
2240 | return 1; | |
2241 | } | |
2242 | ||
cf40bd16 | 2243 | enum mark_type { |
36bfb9bb PZ |
2244 | #define LOCKDEP_STATE(__STATE) __STATE, |
2245 | #include "lockdep_states.h" | |
2246 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2247 | }; |
2248 | ||
fbb9ce95 IM |
2249 | /* |
2250 | * Mark all held locks with a usage bit: | |
2251 | */ | |
1d09daa5 | 2252 | static int |
cf40bd16 | 2253 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2254 | { |
2255 | enum lock_usage_bit usage_bit; | |
2256 | struct held_lock *hlock; | |
2257 | int i; | |
2258 | ||
2259 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2260 | hlock = curr->held_locks + i; | |
2261 | ||
cf2ad4d1 PZ |
2262 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2263 | if (hlock->read) | |
2264 | usage_bit += 1; /* READ */ | |
2265 | ||
2266 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2267 | |
4ff773bb | 2268 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2269 | return 0; |
2270 | } | |
2271 | ||
2272 | return 1; | |
2273 | } | |
2274 | ||
2275 | /* | |
2276 | * Debugging helper: via this flag we know that we are in | |
2277 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2278 | */ | |
2279 | static int early_boot_irqs_enabled; | |
2280 | ||
2281 | void early_boot_irqs_off(void) | |
2282 | { | |
2283 | early_boot_irqs_enabled = 0; | |
2284 | } | |
2285 | ||
2286 | void early_boot_irqs_on(void) | |
2287 | { | |
2288 | early_boot_irqs_enabled = 1; | |
2289 | } | |
2290 | ||
2291 | /* | |
2292 | * Hardirqs will be enabled: | |
2293 | */ | |
6afe40b4 | 2294 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2295 | { |
2296 | struct task_struct *curr = current; | |
fbb9ce95 | 2297 | |
6afe40b4 | 2298 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2299 | |
fbb9ce95 IM |
2300 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2301 | return; | |
2302 | ||
2303 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2304 | return; | |
2305 | ||
2306 | if (unlikely(curr->hardirqs_enabled)) { | |
2307 | debug_atomic_inc(&redundant_hardirqs_on); | |
2308 | return; | |
2309 | } | |
2310 | /* we'll do an OFF -> ON transition: */ | |
2311 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2312 | |
2313 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2314 | return; | |
2315 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2316 | return; | |
2317 | /* | |
2318 | * We are going to turn hardirqs on, so set the | |
2319 | * usage bit for all held locks: | |
2320 | */ | |
cf40bd16 | 2321 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2322 | return; |
2323 | /* | |
2324 | * If we have softirqs enabled, then set the usage | |
2325 | * bit for all held locks. (disabled hardirqs prevented | |
2326 | * this bit from being set before) | |
2327 | */ | |
2328 | if (curr->softirqs_enabled) | |
cf40bd16 | 2329 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2330 | return; |
2331 | ||
8e18257d PZ |
2332 | curr->hardirq_enable_ip = ip; |
2333 | curr->hardirq_enable_event = ++curr->irq_events; | |
2334 | debug_atomic_inc(&hardirqs_on_events); | |
2335 | } | |
81d68a96 | 2336 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2337 | |
1d09daa5 | 2338 | void trace_hardirqs_on(void) |
81d68a96 SR |
2339 | { |
2340 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2341 | } | |
8e18257d PZ |
2342 | EXPORT_SYMBOL(trace_hardirqs_on); |
2343 | ||
2344 | /* | |
2345 | * Hardirqs were disabled: | |
2346 | */ | |
6afe40b4 | 2347 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2348 | { |
2349 | struct task_struct *curr = current; | |
2350 | ||
6afe40b4 | 2351 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2352 | |
8e18257d PZ |
2353 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2354 | return; | |
2355 | ||
2356 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2357 | return; | |
2358 | ||
2359 | if (curr->hardirqs_enabled) { | |
2360 | /* | |
2361 | * We have done an ON -> OFF transition: | |
2362 | */ | |
2363 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2364 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2365 | curr->hardirq_disable_event = ++curr->irq_events; |
2366 | debug_atomic_inc(&hardirqs_off_events); | |
2367 | } else | |
2368 | debug_atomic_inc(&redundant_hardirqs_off); | |
2369 | } | |
81d68a96 | 2370 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2371 | |
1d09daa5 | 2372 | void trace_hardirqs_off(void) |
81d68a96 SR |
2373 | { |
2374 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2375 | } | |
8e18257d PZ |
2376 | EXPORT_SYMBOL(trace_hardirqs_off); |
2377 | ||
2378 | /* | |
2379 | * Softirqs will be enabled: | |
2380 | */ | |
2381 | void trace_softirqs_on(unsigned long ip) | |
2382 | { | |
2383 | struct task_struct *curr = current; | |
2384 | ||
2385 | if (unlikely(!debug_locks)) | |
2386 | return; | |
2387 | ||
2388 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2389 | return; | |
2390 | ||
2391 | if (curr->softirqs_enabled) { | |
2392 | debug_atomic_inc(&redundant_softirqs_on); | |
2393 | return; | |
2394 | } | |
2395 | ||
2396 | /* | |
2397 | * We'll do an OFF -> ON transition: | |
2398 | */ | |
2399 | curr->softirqs_enabled = 1; | |
2400 | curr->softirq_enable_ip = ip; | |
2401 | curr->softirq_enable_event = ++curr->irq_events; | |
2402 | debug_atomic_inc(&softirqs_on_events); | |
2403 | /* | |
2404 | * We are going to turn softirqs on, so set the | |
2405 | * usage bit for all held locks, if hardirqs are | |
2406 | * enabled too: | |
2407 | */ | |
2408 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2409 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2410 | } |
2411 | ||
2412 | /* | |
2413 | * Softirqs were disabled: | |
2414 | */ | |
2415 | void trace_softirqs_off(unsigned long ip) | |
2416 | { | |
2417 | struct task_struct *curr = current; | |
2418 | ||
2419 | if (unlikely(!debug_locks)) | |
2420 | return; | |
2421 | ||
2422 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2423 | return; | |
2424 | ||
2425 | if (curr->softirqs_enabled) { | |
2426 | /* | |
2427 | * We have done an ON -> OFF transition: | |
2428 | */ | |
2429 | curr->softirqs_enabled = 0; | |
2430 | curr->softirq_disable_ip = ip; | |
2431 | curr->softirq_disable_event = ++curr->irq_events; | |
2432 | debug_atomic_inc(&softirqs_off_events); | |
2433 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2434 | } else | |
2435 | debug_atomic_inc(&redundant_softirqs_off); | |
2436 | } | |
2437 | ||
2f850181 | 2438 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2439 | { |
2440 | struct task_struct *curr = current; | |
2441 | ||
2442 | if (unlikely(!debug_locks)) | |
2443 | return; | |
2444 | ||
2445 | /* no reclaim without waiting on it */ | |
2446 | if (!(gfp_mask & __GFP_WAIT)) | |
2447 | return; | |
2448 | ||
2449 | /* this guy won't enter reclaim */ | |
2450 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2451 | return; | |
2452 | ||
2453 | /* We're only interested __GFP_FS allocations for now */ | |
2454 | if (!(gfp_mask & __GFP_FS)) | |
2455 | return; | |
2456 | ||
2f850181 | 2457 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2458 | return; |
2459 | ||
2460 | mark_held_locks(curr, RECLAIM_FS); | |
2461 | } | |
2462 | ||
2f850181 PZ |
2463 | static void check_flags(unsigned long flags); |
2464 | ||
2465 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2466 | { | |
2467 | unsigned long flags; | |
2468 | ||
2469 | if (unlikely(current->lockdep_recursion)) | |
2470 | return; | |
2471 | ||
2472 | raw_local_irq_save(flags); | |
2473 | check_flags(flags); | |
2474 | current->lockdep_recursion = 1; | |
2475 | __lockdep_trace_alloc(gfp_mask, flags); | |
2476 | current->lockdep_recursion = 0; | |
2477 | raw_local_irq_restore(flags); | |
2478 | } | |
2479 | ||
8e18257d PZ |
2480 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2481 | { | |
2482 | /* | |
2483 | * If non-trylock use in a hardirq or softirq context, then | |
2484 | * mark the lock as used in these contexts: | |
2485 | */ | |
2486 | if (!hlock->trylock) { | |
2487 | if (hlock->read) { | |
2488 | if (curr->hardirq_context) | |
2489 | if (!mark_lock(curr, hlock, | |
2490 | LOCK_USED_IN_HARDIRQ_READ)) | |
2491 | return 0; | |
2492 | if (curr->softirq_context) | |
2493 | if (!mark_lock(curr, hlock, | |
2494 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2495 | return 0; | |
2496 | } else { | |
2497 | if (curr->hardirq_context) | |
2498 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2499 | return 0; | |
2500 | if (curr->softirq_context) | |
2501 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2502 | return 0; | |
2503 | } | |
2504 | } | |
2505 | if (!hlock->hardirqs_off) { | |
2506 | if (hlock->read) { | |
2507 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2508 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2509 | return 0; |
2510 | if (curr->softirqs_enabled) | |
2511 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2512 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2513 | return 0; |
2514 | } else { | |
2515 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2516 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2517 | return 0; |
2518 | if (curr->softirqs_enabled) | |
2519 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2520 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2521 | return 0; |
2522 | } | |
2523 | } | |
2524 | ||
cf40bd16 NP |
2525 | /* |
2526 | * We reuse the irq context infrastructure more broadly as a general | |
2527 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2528 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2529 | * allocation). | |
2530 | */ | |
2531 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2532 | if (hlock->read) { | |
2533 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2534 | return 0; | |
2535 | } else { | |
2536 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2537 | return 0; | |
2538 | } | |
2539 | } | |
2540 | ||
8e18257d PZ |
2541 | return 1; |
2542 | } | |
2543 | ||
2544 | static int separate_irq_context(struct task_struct *curr, | |
2545 | struct held_lock *hlock) | |
2546 | { | |
2547 | unsigned int depth = curr->lockdep_depth; | |
2548 | ||
2549 | /* | |
2550 | * Keep track of points where we cross into an interrupt context: | |
2551 | */ | |
2552 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2553 | curr->softirq_context; | |
2554 | if (depth) { | |
2555 | struct held_lock *prev_hlock; | |
2556 | ||
2557 | prev_hlock = curr->held_locks + depth-1; | |
2558 | /* | |
2559 | * If we cross into another context, reset the | |
2560 | * hash key (this also prevents the checking and the | |
2561 | * adding of the dependency to 'prev'): | |
2562 | */ | |
2563 | if (prev_hlock->irq_context != hlock->irq_context) | |
2564 | return 1; | |
2565 | } | |
2566 | return 0; | |
fbb9ce95 IM |
2567 | } |
2568 | ||
8e18257d | 2569 | #else |
fbb9ce95 | 2570 | |
8e18257d PZ |
2571 | static inline |
2572 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2573 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2574 | { |
8e18257d PZ |
2575 | WARN_ON(1); |
2576 | return 1; | |
2577 | } | |
fbb9ce95 | 2578 | |
8e18257d PZ |
2579 | static inline int mark_irqflags(struct task_struct *curr, |
2580 | struct held_lock *hlock) | |
2581 | { | |
2582 | return 1; | |
2583 | } | |
fbb9ce95 | 2584 | |
8e18257d PZ |
2585 | static inline int separate_irq_context(struct task_struct *curr, |
2586 | struct held_lock *hlock) | |
2587 | { | |
2588 | return 0; | |
fbb9ce95 IM |
2589 | } |
2590 | ||
868a23a8 PZ |
2591 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2592 | { | |
2593 | } | |
2594 | ||
8e18257d | 2595 | #endif |
fbb9ce95 IM |
2596 | |
2597 | /* | |
8e18257d | 2598 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2599 | */ |
1d09daa5 | 2600 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2601 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2602 | { |
8e18257d | 2603 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2604 | |
2605 | /* | |
8e18257d PZ |
2606 | * If already set then do not dirty the cacheline, |
2607 | * nor do any checks: | |
fbb9ce95 | 2608 | */ |
f82b217e | 2609 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2610 | return 1; |
2611 | ||
2612 | if (!graph_lock()) | |
2613 | return 0; | |
fbb9ce95 | 2614 | /* |
8e18257d | 2615 | * Make sure we didnt race: |
fbb9ce95 | 2616 | */ |
f82b217e | 2617 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2618 | graph_unlock(); |
2619 | return 1; | |
2620 | } | |
fbb9ce95 | 2621 | |
f82b217e | 2622 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2623 | |
f82b217e | 2624 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2625 | return 0; |
fbb9ce95 | 2626 | |
8e18257d | 2627 | switch (new_bit) { |
5346417e PZ |
2628 | #define LOCKDEP_STATE(__STATE) \ |
2629 | case LOCK_USED_IN_##__STATE: \ | |
2630 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2631 | case LOCK_ENABLED_##__STATE: \ | |
2632 | case LOCK_ENABLED_##__STATE##_READ: | |
2633 | #include "lockdep_states.h" | |
2634 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2635 | ret = mark_lock_irq(curr, this, new_bit); |
2636 | if (!ret) | |
2637 | return 0; | |
2638 | break; | |
2639 | case LOCK_USED: | |
8e18257d PZ |
2640 | debug_atomic_dec(&nr_unused_locks); |
2641 | break; | |
2642 | default: | |
2643 | if (!debug_locks_off_graph_unlock()) | |
2644 | return 0; | |
2645 | WARN_ON(1); | |
2646 | return 0; | |
2647 | } | |
fbb9ce95 | 2648 | |
8e18257d PZ |
2649 | graph_unlock(); |
2650 | ||
2651 | /* | |
2652 | * We must printk outside of the graph_lock: | |
2653 | */ | |
2654 | if (ret == 2) { | |
2655 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2656 | print_lock(this); | |
2657 | print_irqtrace_events(curr); | |
2658 | dump_stack(); | |
2659 | } | |
2660 | ||
2661 | return ret; | |
2662 | } | |
fbb9ce95 IM |
2663 | |
2664 | /* | |
2665 | * Initialize a lock instance's lock-class mapping info: | |
2666 | */ | |
2667 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2668 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2669 | { |
c8a25005 PZ |
2670 | lock->class_cache = NULL; |
2671 | #ifdef CONFIG_LOCK_STAT | |
2672 | lock->cpu = raw_smp_processor_id(); | |
2673 | #endif | |
2674 | ||
2675 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2676 | lock->name = "NULL"; | |
fbb9ce95 | 2677 | return; |
c8a25005 PZ |
2678 | } |
2679 | ||
2680 | lock->name = name; | |
fbb9ce95 IM |
2681 | |
2682 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2683 | return; | |
fbb9ce95 IM |
2684 | /* |
2685 | * Sanity check, the lock-class key must be persistent: | |
2686 | */ | |
2687 | if (!static_obj(key)) { | |
2688 | printk("BUG: key %p not in .data!\n", key); | |
2689 | DEBUG_LOCKS_WARN_ON(1); | |
2690 | return; | |
2691 | } | |
fbb9ce95 | 2692 | lock->key = key; |
c8a25005 PZ |
2693 | |
2694 | if (unlikely(!debug_locks)) | |
2695 | return; | |
2696 | ||
4dfbb9d8 PZ |
2697 | if (subclass) |
2698 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2699 | } |
fbb9ce95 IM |
2700 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2701 | ||
2702 | /* | |
2703 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2704 | * We maintain the dependency maps and validate the locking attempt: | |
2705 | */ | |
2706 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2707 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
2708 | struct lockdep_map *nest_lock, unsigned long ip, |
2709 | int references) | |
fbb9ce95 IM |
2710 | { |
2711 | struct task_struct *curr = current; | |
d6d897ce | 2712 | struct lock_class *class = NULL; |
fbb9ce95 | 2713 | struct held_lock *hlock; |
fbb9ce95 IM |
2714 | unsigned int depth, id; |
2715 | int chain_head = 0; | |
bb97a91e | 2716 | int class_idx; |
fbb9ce95 IM |
2717 | u64 chain_key; |
2718 | ||
f20786ff PZ |
2719 | if (!prove_locking) |
2720 | check = 1; | |
2721 | ||
fbb9ce95 IM |
2722 | if (unlikely(!debug_locks)) |
2723 | return 0; | |
2724 | ||
2725 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2726 | return 0; | |
2727 | ||
2728 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2729 | debug_locks_off(); | |
2730 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2731 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2732 | dump_stack(); |
fbb9ce95 IM |
2733 | return 0; |
2734 | } | |
2735 | ||
d6d897ce IM |
2736 | if (!subclass) |
2737 | class = lock->class_cache; | |
2738 | /* | |
2739 | * Not cached yet or subclass? | |
2740 | */ | |
fbb9ce95 | 2741 | if (unlikely(!class)) { |
4dfbb9d8 | 2742 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2743 | if (!class) |
2744 | return 0; | |
2745 | } | |
2746 | debug_atomic_inc((atomic_t *)&class->ops); | |
2747 | if (very_verbose(class)) { | |
2748 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2749 | if (class->name_version > 1) | |
2750 | printk("#%d", class->name_version); | |
2751 | printk("\n"); | |
2752 | dump_stack(); | |
2753 | } | |
2754 | ||
2755 | /* | |
2756 | * Add the lock to the list of currently held locks. | |
2757 | * (we dont increase the depth just yet, up until the | |
2758 | * dependency checks are done) | |
2759 | */ | |
2760 | depth = curr->lockdep_depth; | |
2761 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2762 | return 0; | |
2763 | ||
bb97a91e PZ |
2764 | class_idx = class - lock_classes + 1; |
2765 | ||
2766 | if (depth) { | |
2767 | hlock = curr->held_locks + depth - 1; | |
2768 | if (hlock->class_idx == class_idx && nest_lock) { | |
2769 | if (hlock->references) | |
2770 | hlock->references++; | |
2771 | else | |
2772 | hlock->references = 2; | |
2773 | ||
2774 | return 1; | |
2775 | } | |
2776 | } | |
2777 | ||
fbb9ce95 | 2778 | hlock = curr->held_locks + depth; |
f82b217e DJ |
2779 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2780 | return 0; | |
bb97a91e | 2781 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
2782 | hlock->acquire_ip = ip; |
2783 | hlock->instance = lock; | |
7531e2f3 | 2784 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2785 | hlock->trylock = trylock; |
2786 | hlock->read = read; | |
2787 | hlock->check = check; | |
6951b12a | 2788 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 2789 | hlock->references = references; |
f20786ff PZ |
2790 | #ifdef CONFIG_LOCK_STAT |
2791 | hlock->waittime_stamp = 0; | |
2792 | hlock->holdtime_stamp = sched_clock(); | |
2793 | #endif | |
fbb9ce95 | 2794 | |
8e18257d PZ |
2795 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2796 | return 0; | |
2797 | ||
fbb9ce95 | 2798 | /* mark it as used: */ |
4ff773bb | 2799 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2800 | return 0; |
8e18257d | 2801 | |
fbb9ce95 | 2802 | /* |
17aacfb9 | 2803 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2804 | * lock keys along the dependency chain. We save the hash value |
2805 | * at every step so that we can get the current hash easily | |
2806 | * after unlock. The chain hash is then used to cache dependency | |
2807 | * results. | |
2808 | * | |
2809 | * The 'key ID' is what is the most compact key value to drive | |
2810 | * the hash, not class->key. | |
2811 | */ | |
2812 | id = class - lock_classes; | |
2813 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2814 | return 0; | |
2815 | ||
2816 | chain_key = curr->curr_chain_key; | |
2817 | if (!depth) { | |
2818 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2819 | return 0; | |
2820 | chain_head = 1; | |
2821 | } | |
2822 | ||
2823 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2824 | if (separate_irq_context(curr, hlock)) { |
2825 | chain_key = 0; | |
2826 | chain_head = 1; | |
fbb9ce95 | 2827 | } |
fbb9ce95 | 2828 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2829 | |
3aa416b0 | 2830 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2831 | return 0; |
381a2292 | 2832 | |
3aa416b0 | 2833 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2834 | curr->lockdep_depth++; |
2835 | check_chain_key(curr); | |
60e114d1 JP |
2836 | #ifdef CONFIG_DEBUG_LOCKDEP |
2837 | if (unlikely(!debug_locks)) | |
2838 | return 0; | |
2839 | #endif | |
fbb9ce95 IM |
2840 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2841 | debug_locks_off(); | |
2842 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2843 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2844 | dump_stack(); |
fbb9ce95 IM |
2845 | return 0; |
2846 | } | |
381a2292 | 2847 | |
fbb9ce95 IM |
2848 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2849 | max_lockdep_depth = curr->lockdep_depth; | |
2850 | ||
2851 | return 1; | |
2852 | } | |
2853 | ||
2854 | static int | |
2855 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2856 | unsigned long ip) | |
2857 | { | |
2858 | if (!debug_locks_off()) | |
2859 | return 0; | |
2860 | if (debug_locks_silent) | |
2861 | return 0; | |
2862 | ||
2863 | printk("\n=====================================\n"); | |
2864 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2865 | printk( "-------------------------------------\n"); | |
2866 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2867 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2868 | print_lockdep_cache(lock); |
2869 | printk(") at:\n"); | |
2870 | print_ip_sym(ip); | |
2871 | printk("but there are no more locks to release!\n"); | |
2872 | printk("\nother info that might help us debug this:\n"); | |
2873 | lockdep_print_held_locks(curr); | |
2874 | ||
2875 | printk("\nstack backtrace:\n"); | |
2876 | dump_stack(); | |
2877 | ||
2878 | return 0; | |
2879 | } | |
2880 | ||
2881 | /* | |
2882 | * Common debugging checks for both nested and non-nested unlock: | |
2883 | */ | |
2884 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2885 | unsigned long ip) | |
2886 | { | |
2887 | if (unlikely(!debug_locks)) | |
2888 | return 0; | |
2889 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2890 | return 0; | |
2891 | ||
2892 | if (curr->lockdep_depth <= 0) | |
2893 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2894 | ||
2895 | return 1; | |
2896 | } | |
2897 | ||
bb97a91e PZ |
2898 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
2899 | { | |
2900 | if (hlock->instance == lock) | |
2901 | return 1; | |
2902 | ||
2903 | if (hlock->references) { | |
2904 | struct lock_class *class = lock->class_cache; | |
2905 | ||
2906 | if (!class) | |
2907 | class = look_up_lock_class(lock, 0); | |
2908 | ||
2909 | if (DEBUG_LOCKS_WARN_ON(!class)) | |
2910 | return 0; | |
2911 | ||
2912 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) | |
2913 | return 0; | |
2914 | ||
2915 | if (hlock->class_idx == class - lock_classes + 1) | |
2916 | return 1; | |
2917 | } | |
2918 | ||
2919 | return 0; | |
2920 | } | |
2921 | ||
64aa348e | 2922 | static int |
00ef9f73 PZ |
2923 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2924 | struct lock_class_key *key, unsigned int subclass, | |
2925 | unsigned long ip) | |
64aa348e PZ |
2926 | { |
2927 | struct task_struct *curr = current; | |
2928 | struct held_lock *hlock, *prev_hlock; | |
2929 | struct lock_class *class; | |
2930 | unsigned int depth; | |
2931 | int i; | |
2932 | ||
2933 | depth = curr->lockdep_depth; | |
2934 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2935 | return 0; | |
2936 | ||
2937 | prev_hlock = NULL; | |
2938 | for (i = depth-1; i >= 0; i--) { | |
2939 | hlock = curr->held_locks + i; | |
2940 | /* | |
2941 | * We must not cross into another context: | |
2942 | */ | |
2943 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2944 | break; | |
bb97a91e | 2945 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
2946 | goto found_it; |
2947 | prev_hlock = hlock; | |
2948 | } | |
2949 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2950 | ||
2951 | found_it: | |
00ef9f73 | 2952 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2953 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2954 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2955 | |
2956 | curr->lockdep_depth = i; | |
2957 | curr->curr_chain_key = hlock->prev_chain_key; | |
2958 | ||
2959 | for (; i < depth; i++) { | |
2960 | hlock = curr->held_locks + i; | |
2961 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2962 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2963 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
2964 | hlock->nest_lock, hlock->acquire_ip, |
2965 | hlock->references)) | |
64aa348e PZ |
2966 | return 0; |
2967 | } | |
2968 | ||
2969 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2970 | return 0; | |
2971 | return 1; | |
2972 | } | |
2973 | ||
fbb9ce95 IM |
2974 | /* |
2975 | * Remove the lock to the list of currently held locks in a | |
2976 | * potentially non-nested (out of order) manner. This is a | |
2977 | * relatively rare operation, as all the unlock APIs default | |
2978 | * to nested mode (which uses lock_release()): | |
2979 | */ | |
2980 | static int | |
2981 | lock_release_non_nested(struct task_struct *curr, | |
2982 | struct lockdep_map *lock, unsigned long ip) | |
2983 | { | |
2984 | struct held_lock *hlock, *prev_hlock; | |
2985 | unsigned int depth; | |
2986 | int i; | |
2987 | ||
2988 | /* | |
2989 | * Check whether the lock exists in the current stack | |
2990 | * of held locks: | |
2991 | */ | |
2992 | depth = curr->lockdep_depth; | |
2993 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2994 | return 0; | |
2995 | ||
2996 | prev_hlock = NULL; | |
2997 | for (i = depth-1; i >= 0; i--) { | |
2998 | hlock = curr->held_locks + i; | |
2999 | /* | |
3000 | * We must not cross into another context: | |
3001 | */ | |
3002 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3003 | break; | |
bb97a91e | 3004 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3005 | goto found_it; |
3006 | prev_hlock = hlock; | |
3007 | } | |
3008 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3009 | ||
3010 | found_it: | |
bb97a91e PZ |
3011 | if (hlock->instance == lock) |
3012 | lock_release_holdtime(hlock); | |
3013 | ||
3014 | if (hlock->references) { | |
3015 | hlock->references--; | |
3016 | if (hlock->references) { | |
3017 | /* | |
3018 | * We had, and after removing one, still have | |
3019 | * references, the current lock stack is still | |
3020 | * valid. We're done! | |
3021 | */ | |
3022 | return 1; | |
3023 | } | |
3024 | } | |
f20786ff | 3025 | |
fbb9ce95 IM |
3026 | /* |
3027 | * We have the right lock to unlock, 'hlock' points to it. | |
3028 | * Now we remove it from the stack, and add back the other | |
3029 | * entries (if any), recalculating the hash along the way: | |
3030 | */ | |
bb97a91e | 3031 | |
fbb9ce95 IM |
3032 | curr->lockdep_depth = i; |
3033 | curr->curr_chain_key = hlock->prev_chain_key; | |
3034 | ||
3035 | for (i++; i < depth; i++) { | |
3036 | hlock = curr->held_locks + i; | |
3037 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3038 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3039 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3040 | hlock->nest_lock, hlock->acquire_ip, |
3041 | hlock->references)) | |
fbb9ce95 IM |
3042 | return 0; |
3043 | } | |
3044 | ||
3045 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
3046 | return 0; | |
3047 | return 1; | |
3048 | } | |
3049 | ||
3050 | /* | |
3051 | * Remove the lock to the list of currently held locks - this gets | |
3052 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3053 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3054 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3055 | */ | |
3056 | static int lock_release_nested(struct task_struct *curr, | |
3057 | struct lockdep_map *lock, unsigned long ip) | |
3058 | { | |
3059 | struct held_lock *hlock; | |
3060 | unsigned int depth; | |
3061 | ||
3062 | /* | |
3063 | * Pop off the top of the lock stack: | |
3064 | */ | |
3065 | depth = curr->lockdep_depth - 1; | |
3066 | hlock = curr->held_locks + depth; | |
3067 | ||
3068 | /* | |
3069 | * Is the unlock non-nested: | |
3070 | */ | |
bb97a91e | 3071 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3072 | return lock_release_non_nested(curr, lock, ip); |
3073 | curr->lockdep_depth--; | |
3074 | ||
3075 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
3076 | return 0; | |
3077 | ||
3078 | curr->curr_chain_key = hlock->prev_chain_key; | |
3079 | ||
f20786ff PZ |
3080 | lock_release_holdtime(hlock); |
3081 | ||
fbb9ce95 IM |
3082 | #ifdef CONFIG_DEBUG_LOCKDEP |
3083 | hlock->prev_chain_key = 0; | |
f82b217e | 3084 | hlock->class_idx = 0; |
fbb9ce95 IM |
3085 | hlock->acquire_ip = 0; |
3086 | hlock->irq_context = 0; | |
3087 | #endif | |
3088 | return 1; | |
3089 | } | |
3090 | ||
3091 | /* | |
3092 | * Remove the lock to the list of currently held locks - this gets | |
3093 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3094 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3095 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3096 | */ | |
3097 | static void | |
3098 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3099 | { | |
3100 | struct task_struct *curr = current; | |
3101 | ||
3102 | if (!check_unlock(curr, lock, ip)) | |
3103 | return; | |
3104 | ||
3105 | if (nested) { | |
3106 | if (!lock_release_nested(curr, lock, ip)) | |
3107 | return; | |
3108 | } else { | |
3109 | if (!lock_release_non_nested(curr, lock, ip)) | |
3110 | return; | |
3111 | } | |
3112 | ||
3113 | check_chain_key(curr); | |
3114 | } | |
3115 | ||
f607c668 PZ |
3116 | static int __lock_is_held(struct lockdep_map *lock) |
3117 | { | |
3118 | struct task_struct *curr = current; | |
3119 | int i; | |
3120 | ||
3121 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3122 | struct held_lock *hlock = curr->held_locks + i; |
3123 | ||
3124 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3125 | return 1; |
3126 | } | |
3127 | ||
3128 | return 0; | |
3129 | } | |
3130 | ||
fbb9ce95 IM |
3131 | /* |
3132 | * Check whether we follow the irq-flags state precisely: | |
3133 | */ | |
1d09daa5 | 3134 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3135 | { |
992860e9 IM |
3136 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3137 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3138 | if (!debug_locks) |
3139 | return; | |
3140 | ||
5f9fa8a6 IM |
3141 | if (irqs_disabled_flags(flags)) { |
3142 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3143 | printk("possible reason: unannotated irqs-off.\n"); | |
3144 | } | |
3145 | } else { | |
3146 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3147 | printk("possible reason: unannotated irqs-on.\n"); | |
3148 | } | |
3149 | } | |
fbb9ce95 IM |
3150 | |
3151 | /* | |
3152 | * We dont accurately track softirq state in e.g. | |
3153 | * hardirq contexts (such as on 4KSTACKS), so only | |
3154 | * check if not in hardirq contexts: | |
3155 | */ | |
3156 | if (!hardirq_count()) { | |
3157 | if (softirq_count()) | |
3158 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3159 | else | |
3160 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3161 | } | |
3162 | ||
3163 | if (!debug_locks) | |
3164 | print_irqtrace_events(current); | |
3165 | #endif | |
3166 | } | |
3167 | ||
00ef9f73 PZ |
3168 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3169 | struct lock_class_key *key, unsigned int subclass, | |
3170 | unsigned long ip) | |
64aa348e PZ |
3171 | { |
3172 | unsigned long flags; | |
3173 | ||
3174 | if (unlikely(current->lockdep_recursion)) | |
3175 | return; | |
3176 | ||
3177 | raw_local_irq_save(flags); | |
3178 | current->lockdep_recursion = 1; | |
3179 | check_flags(flags); | |
00ef9f73 | 3180 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3181 | check_chain_key(current); |
3182 | current->lockdep_recursion = 0; | |
3183 | raw_local_irq_restore(flags); | |
3184 | } | |
00ef9f73 | 3185 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3186 | |
fbb9ce95 IM |
3187 | /* |
3188 | * We are not always called with irqs disabled - do that here, | |
3189 | * and also avoid lockdep recursion: | |
3190 | */ | |
1d09daa5 | 3191 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3192 | int trylock, int read, int check, |
3193 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3194 | { |
3195 | unsigned long flags; | |
3196 | ||
efed792d PZ |
3197 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
3198 | ||
fbb9ce95 IM |
3199 | if (unlikely(current->lockdep_recursion)) |
3200 | return; | |
3201 | ||
3202 | raw_local_irq_save(flags); | |
3203 | check_flags(flags); | |
3204 | ||
3205 | current->lockdep_recursion = 1; | |
3206 | __lock_acquire(lock, subclass, trylock, read, check, | |
bb97a91e | 3207 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3208 | current->lockdep_recursion = 0; |
3209 | raw_local_irq_restore(flags); | |
3210 | } | |
fbb9ce95 IM |
3211 | EXPORT_SYMBOL_GPL(lock_acquire); |
3212 | ||
1d09daa5 | 3213 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3214 | unsigned long ip) |
fbb9ce95 IM |
3215 | { |
3216 | unsigned long flags; | |
3217 | ||
efed792d PZ |
3218 | trace_lock_release(lock, nested, ip); |
3219 | ||
fbb9ce95 IM |
3220 | if (unlikely(current->lockdep_recursion)) |
3221 | return; | |
3222 | ||
3223 | raw_local_irq_save(flags); | |
3224 | check_flags(flags); | |
3225 | current->lockdep_recursion = 1; | |
3226 | __lock_release(lock, nested, ip); | |
3227 | current->lockdep_recursion = 0; | |
3228 | raw_local_irq_restore(flags); | |
3229 | } | |
fbb9ce95 IM |
3230 | EXPORT_SYMBOL_GPL(lock_release); |
3231 | ||
f607c668 PZ |
3232 | int lock_is_held(struct lockdep_map *lock) |
3233 | { | |
3234 | unsigned long flags; | |
3235 | int ret = 0; | |
3236 | ||
3237 | if (unlikely(current->lockdep_recursion)) | |
3238 | return ret; | |
3239 | ||
3240 | raw_local_irq_save(flags); | |
3241 | check_flags(flags); | |
3242 | ||
3243 | current->lockdep_recursion = 1; | |
3244 | ret = __lock_is_held(lock); | |
3245 | current->lockdep_recursion = 0; | |
3246 | raw_local_irq_restore(flags); | |
3247 | ||
3248 | return ret; | |
3249 | } | |
3250 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3251 | ||
cf40bd16 NP |
3252 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3253 | { | |
3254 | current->lockdep_reclaim_gfp = gfp_mask; | |
3255 | } | |
3256 | ||
3257 | void lockdep_clear_current_reclaim_state(void) | |
3258 | { | |
3259 | current->lockdep_reclaim_gfp = 0; | |
3260 | } | |
3261 | ||
f20786ff PZ |
3262 | #ifdef CONFIG_LOCK_STAT |
3263 | static int | |
3264 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3265 | unsigned long ip) | |
3266 | { | |
3267 | if (!debug_locks_off()) | |
3268 | return 0; | |
3269 | if (debug_locks_silent) | |
3270 | return 0; | |
3271 | ||
3272 | printk("\n=================================\n"); | |
3273 | printk( "[ BUG: bad contention detected! ]\n"); | |
3274 | printk( "---------------------------------\n"); | |
3275 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3276 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3277 | print_lockdep_cache(lock); |
3278 | printk(") at:\n"); | |
3279 | print_ip_sym(ip); | |
3280 | printk("but there are no locks held!\n"); | |
3281 | printk("\nother info that might help us debug this:\n"); | |
3282 | lockdep_print_held_locks(curr); | |
3283 | ||
3284 | printk("\nstack backtrace:\n"); | |
3285 | dump_stack(); | |
3286 | ||
3287 | return 0; | |
3288 | } | |
3289 | ||
3290 | static void | |
3291 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3292 | { | |
3293 | struct task_struct *curr = current; | |
3294 | struct held_lock *hlock, *prev_hlock; | |
3295 | struct lock_class_stats *stats; | |
3296 | unsigned int depth; | |
c7e78cff | 3297 | int i, contention_point, contending_point; |
f20786ff PZ |
3298 | |
3299 | depth = curr->lockdep_depth; | |
3300 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3301 | return; | |
3302 | ||
3303 | prev_hlock = NULL; | |
3304 | for (i = depth-1; i >= 0; i--) { | |
3305 | hlock = curr->held_locks + i; | |
3306 | /* | |
3307 | * We must not cross into another context: | |
3308 | */ | |
3309 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3310 | break; | |
bb97a91e | 3311 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3312 | goto found_it; |
3313 | prev_hlock = hlock; | |
3314 | } | |
3315 | print_lock_contention_bug(curr, lock, ip); | |
3316 | return; | |
3317 | ||
3318 | found_it: | |
bb97a91e PZ |
3319 | if (hlock->instance != lock) |
3320 | return; | |
3321 | ||
f20786ff PZ |
3322 | hlock->waittime_stamp = sched_clock(); |
3323 | ||
c7e78cff PZ |
3324 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3325 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3326 | lock->ip); | |
f20786ff | 3327 | |
f82b217e | 3328 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3329 | if (contention_point < LOCKSTAT_POINTS) |
3330 | stats->contention_point[contention_point]++; | |
3331 | if (contending_point < LOCKSTAT_POINTS) | |
3332 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3333 | if (lock->cpu != smp_processor_id()) |
3334 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3335 | put_lock_stats(stats); |
3336 | } | |
3337 | ||
3338 | static void | |
c7e78cff | 3339 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3340 | { |
3341 | struct task_struct *curr = current; | |
3342 | struct held_lock *hlock, *prev_hlock; | |
3343 | struct lock_class_stats *stats; | |
3344 | unsigned int depth; | |
3345 | u64 now; | |
96645678 PZ |
3346 | s64 waittime = 0; |
3347 | int i, cpu; | |
f20786ff PZ |
3348 | |
3349 | depth = curr->lockdep_depth; | |
3350 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3351 | return; | |
3352 | ||
3353 | prev_hlock = NULL; | |
3354 | for (i = depth-1; i >= 0; i--) { | |
3355 | hlock = curr->held_locks + i; | |
3356 | /* | |
3357 | * We must not cross into another context: | |
3358 | */ | |
3359 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3360 | break; | |
bb97a91e | 3361 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3362 | goto found_it; |
3363 | prev_hlock = hlock; | |
3364 | } | |
3365 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3366 | return; | |
3367 | ||
3368 | found_it: | |
bb97a91e PZ |
3369 | if (hlock->instance != lock) |
3370 | return; | |
3371 | ||
96645678 PZ |
3372 | cpu = smp_processor_id(); |
3373 | if (hlock->waittime_stamp) { | |
3374 | now = sched_clock(); | |
3375 | waittime = now - hlock->waittime_stamp; | |
3376 | hlock->holdtime_stamp = now; | |
3377 | } | |
f20786ff | 3378 | |
2062501a FW |
3379 | trace_lock_acquired(lock, ip, waittime); |
3380 | ||
f82b217e | 3381 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3382 | if (waittime) { |
3383 | if (hlock->read) | |
3384 | lock_time_inc(&stats->read_waittime, waittime); | |
3385 | else | |
3386 | lock_time_inc(&stats->write_waittime, waittime); | |
3387 | } | |
3388 | if (lock->cpu != cpu) | |
3389 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3390 | put_lock_stats(stats); |
96645678 PZ |
3391 | |
3392 | lock->cpu = cpu; | |
c7e78cff | 3393 | lock->ip = ip; |
f20786ff PZ |
3394 | } |
3395 | ||
3396 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3397 | { | |
3398 | unsigned long flags; | |
3399 | ||
efed792d PZ |
3400 | trace_lock_contended(lock, ip); |
3401 | ||
f20786ff PZ |
3402 | if (unlikely(!lock_stat)) |
3403 | return; | |
3404 | ||
3405 | if (unlikely(current->lockdep_recursion)) | |
3406 | return; | |
3407 | ||
3408 | raw_local_irq_save(flags); | |
3409 | check_flags(flags); | |
3410 | current->lockdep_recursion = 1; | |
3411 | __lock_contended(lock, ip); | |
3412 | current->lockdep_recursion = 0; | |
3413 | raw_local_irq_restore(flags); | |
3414 | } | |
3415 | EXPORT_SYMBOL_GPL(lock_contended); | |
3416 | ||
c7e78cff | 3417 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3418 | { |
3419 | unsigned long flags; | |
3420 | ||
3421 | if (unlikely(!lock_stat)) | |
3422 | return; | |
3423 | ||
3424 | if (unlikely(current->lockdep_recursion)) | |
3425 | return; | |
3426 | ||
3427 | raw_local_irq_save(flags); | |
3428 | check_flags(flags); | |
3429 | current->lockdep_recursion = 1; | |
c7e78cff | 3430 | __lock_acquired(lock, ip); |
f20786ff PZ |
3431 | current->lockdep_recursion = 0; |
3432 | raw_local_irq_restore(flags); | |
3433 | } | |
3434 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3435 | #endif | |
3436 | ||
fbb9ce95 IM |
3437 | /* |
3438 | * Used by the testsuite, sanitize the validator state | |
3439 | * after a simulated failure: | |
3440 | */ | |
3441 | ||
3442 | void lockdep_reset(void) | |
3443 | { | |
3444 | unsigned long flags; | |
23d95a03 | 3445 | int i; |
fbb9ce95 IM |
3446 | |
3447 | raw_local_irq_save(flags); | |
3448 | current->curr_chain_key = 0; | |
3449 | current->lockdep_depth = 0; | |
3450 | current->lockdep_recursion = 0; | |
3451 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3452 | nr_hardirq_chains = 0; | |
3453 | nr_softirq_chains = 0; | |
3454 | nr_process_chains = 0; | |
3455 | debug_locks = 1; | |
23d95a03 IM |
3456 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3457 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3458 | raw_local_irq_restore(flags); |
3459 | } | |
3460 | ||
3461 | static void zap_class(struct lock_class *class) | |
3462 | { | |
3463 | int i; | |
3464 | ||
3465 | /* | |
3466 | * Remove all dependencies this lock is | |
3467 | * involved in: | |
3468 | */ | |
3469 | for (i = 0; i < nr_list_entries; i++) { | |
3470 | if (list_entries[i].class == class) | |
3471 | list_del_rcu(&list_entries[i].entry); | |
3472 | } | |
3473 | /* | |
3474 | * Unhash the class and remove it from the all_lock_classes list: | |
3475 | */ | |
3476 | list_del_rcu(&class->hash_entry); | |
3477 | list_del_rcu(&class->lock_entry); | |
3478 | ||
8bfe0298 | 3479 | class->key = NULL; |
fbb9ce95 IM |
3480 | } |
3481 | ||
fabe874a | 3482 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3483 | { |
3484 | return addr >= start && addr < start + size; | |
3485 | } | |
3486 | ||
3487 | void lockdep_free_key_range(void *start, unsigned long size) | |
3488 | { | |
3489 | struct lock_class *class, *next; | |
3490 | struct list_head *head; | |
3491 | unsigned long flags; | |
3492 | int i; | |
5a26db5b | 3493 | int locked; |
fbb9ce95 IM |
3494 | |
3495 | raw_local_irq_save(flags); | |
5a26db5b | 3496 | locked = graph_lock(); |
fbb9ce95 IM |
3497 | |
3498 | /* | |
3499 | * Unhash all classes that were created by this module: | |
3500 | */ | |
3501 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3502 | head = classhash_table + i; | |
3503 | if (list_empty(head)) | |
3504 | continue; | |
fabe874a | 3505 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3506 | if (within(class->key, start, size)) |
3507 | zap_class(class); | |
fabe874a AV |
3508 | else if (within(class->name, start, size)) |
3509 | zap_class(class); | |
3510 | } | |
fbb9ce95 IM |
3511 | } |
3512 | ||
5a26db5b NP |
3513 | if (locked) |
3514 | graph_unlock(); | |
fbb9ce95 IM |
3515 | raw_local_irq_restore(flags); |
3516 | } | |
3517 | ||
3518 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3519 | { | |
d6d897ce | 3520 | struct lock_class *class, *next; |
fbb9ce95 IM |
3521 | struct list_head *head; |
3522 | unsigned long flags; | |
3523 | int i, j; | |
5a26db5b | 3524 | int locked; |
fbb9ce95 IM |
3525 | |
3526 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3527 | |
3528 | /* | |
d6d897ce IM |
3529 | * Remove all classes this lock might have: |
3530 | */ | |
3531 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3532 | /* | |
3533 | * If the class exists we look it up and zap it: | |
3534 | */ | |
3535 | class = look_up_lock_class(lock, j); | |
3536 | if (class) | |
3537 | zap_class(class); | |
3538 | } | |
3539 | /* | |
3540 | * Debug check: in the end all mapped classes should | |
3541 | * be gone. | |
fbb9ce95 | 3542 | */ |
5a26db5b | 3543 | locked = graph_lock(); |
fbb9ce95 IM |
3544 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3545 | head = classhash_table + i; | |
3546 | if (list_empty(head)) | |
3547 | continue; | |
3548 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3549 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3550 | if (debug_locks_off_graph_unlock()) |
3551 | WARN_ON(1); | |
d6d897ce | 3552 | goto out_restore; |
fbb9ce95 IM |
3553 | } |
3554 | } | |
3555 | } | |
5a26db5b NP |
3556 | if (locked) |
3557 | graph_unlock(); | |
d6d897ce IM |
3558 | |
3559 | out_restore: | |
fbb9ce95 IM |
3560 | raw_local_irq_restore(flags); |
3561 | } | |
3562 | ||
1499993c | 3563 | void lockdep_init(void) |
fbb9ce95 IM |
3564 | { |
3565 | int i; | |
3566 | ||
3567 | /* | |
3568 | * Some architectures have their own start_kernel() | |
3569 | * code which calls lockdep_init(), while we also | |
3570 | * call lockdep_init() from the start_kernel() itself, | |
3571 | * and we want to initialize the hashes only once: | |
3572 | */ | |
3573 | if (lockdep_initialized) | |
3574 | return; | |
3575 | ||
3576 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3577 | INIT_LIST_HEAD(classhash_table + i); | |
3578 | ||
3579 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3580 | INIT_LIST_HEAD(chainhash_table + i); | |
3581 | ||
3582 | lockdep_initialized = 1; | |
3583 | } | |
3584 | ||
3585 | void __init lockdep_info(void) | |
3586 | { | |
3587 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3588 | ||
b0788caf | 3589 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3590 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3591 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3592 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3593 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3594 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3595 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3596 | ||
3597 | printk(" memory used by lock dependency info: %lu kB\n", | |
3598 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3599 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3600 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3601 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 3602 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 3603 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 3604 | + sizeof(struct circular_queue) |
4dd861d6 | 3605 | #endif |
90629209 | 3606 | ) / 1024 |
4dd861d6 | 3607 | ); |
fbb9ce95 IM |
3608 | |
3609 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3610 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3611 | ||
3612 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3613 | if (lockdep_init_error) { |
3614 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3615 | printk("Call stack leading to lockdep invocation was:\n"); | |
3616 | print_stack_trace(&lockdep_init_trace, 0); | |
3617 | } | |
fbb9ce95 IM |
3618 | #endif |
3619 | } | |
3620 | ||
fbb9ce95 IM |
3621 | static void |
3622 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3623 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3624 | { |
3625 | if (!debug_locks_off()) | |
3626 | return; | |
3627 | if (debug_locks_silent) | |
3628 | return; | |
3629 | ||
3630 | printk("\n=========================\n"); | |
3631 | printk( "[ BUG: held lock freed! ]\n"); | |
3632 | printk( "-------------------------\n"); | |
3633 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3634 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3635 | print_lock(hlock); |
fbb9ce95 IM |
3636 | lockdep_print_held_locks(curr); |
3637 | ||
3638 | printk("\nstack backtrace:\n"); | |
3639 | dump_stack(); | |
3640 | } | |
3641 | ||
54561783 ON |
3642 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3643 | const void* lock_from, unsigned long lock_len) | |
3644 | { | |
3645 | return lock_from + lock_len <= mem_from || | |
3646 | mem_from + mem_len <= lock_from; | |
3647 | } | |
3648 | ||
fbb9ce95 IM |
3649 | /* |
3650 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3651 | * is destroyed or reinitialized - this code checks whether there is | |
3652 | * any held lock in the memory range of <from> to <to>: | |
3653 | */ | |
3654 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3655 | { | |
fbb9ce95 IM |
3656 | struct task_struct *curr = current; |
3657 | struct held_lock *hlock; | |
3658 | unsigned long flags; | |
3659 | int i; | |
3660 | ||
3661 | if (unlikely(!debug_locks)) | |
3662 | return; | |
3663 | ||
3664 | local_irq_save(flags); | |
3665 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3666 | hlock = curr->held_locks + i; | |
3667 | ||
54561783 ON |
3668 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3669 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3670 | continue; |
3671 | ||
54561783 | 3672 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3673 | break; |
3674 | } | |
3675 | local_irq_restore(flags); | |
3676 | } | |
ed07536e | 3677 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3678 | |
3679 | static void print_held_locks_bug(struct task_struct *curr) | |
3680 | { | |
3681 | if (!debug_locks_off()) | |
3682 | return; | |
3683 | if (debug_locks_silent) | |
3684 | return; | |
3685 | ||
3686 | printk("\n=====================================\n"); | |
3687 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3688 | printk( "-------------------------------------\n"); | |
3689 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3690 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3691 | lockdep_print_held_locks(curr); |
3692 | ||
3693 | printk("\nstack backtrace:\n"); | |
3694 | dump_stack(); | |
3695 | } | |
3696 | ||
3697 | void debug_check_no_locks_held(struct task_struct *task) | |
3698 | { | |
3699 | if (unlikely(task->lockdep_depth > 0)) | |
3700 | print_held_locks_bug(task); | |
3701 | } | |
3702 | ||
3703 | void debug_show_all_locks(void) | |
3704 | { | |
3705 | struct task_struct *g, *p; | |
3706 | int count = 10; | |
3707 | int unlock = 1; | |
3708 | ||
9c35dd7f JP |
3709 | if (unlikely(!debug_locks)) { |
3710 | printk("INFO: lockdep is turned off.\n"); | |
3711 | return; | |
3712 | } | |
fbb9ce95 IM |
3713 | printk("\nShowing all locks held in the system:\n"); |
3714 | ||
3715 | /* | |
3716 | * Here we try to get the tasklist_lock as hard as possible, | |
3717 | * if not successful after 2 seconds we ignore it (but keep | |
3718 | * trying). This is to enable a debug printout even if a | |
3719 | * tasklist_lock-holding task deadlocks or crashes. | |
3720 | */ | |
3721 | retry: | |
3722 | if (!read_trylock(&tasklist_lock)) { | |
3723 | if (count == 10) | |
3724 | printk("hm, tasklist_lock locked, retrying... "); | |
3725 | if (count) { | |
3726 | count--; | |
3727 | printk(" #%d", 10-count); | |
3728 | mdelay(200); | |
3729 | goto retry; | |
3730 | } | |
3731 | printk(" ignoring it.\n"); | |
3732 | unlock = 0; | |
46fec7ac | 3733 | } else { |
3734 | if (count != 10) | |
3735 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3736 | } |
fbb9ce95 IM |
3737 | |
3738 | do_each_thread(g, p) { | |
85684873 IM |
3739 | /* |
3740 | * It's not reliable to print a task's held locks | |
3741 | * if it's not sleeping (or if it's not the current | |
3742 | * task): | |
3743 | */ | |
3744 | if (p->state == TASK_RUNNING && p != current) | |
3745 | continue; | |
fbb9ce95 IM |
3746 | if (p->lockdep_depth) |
3747 | lockdep_print_held_locks(p); | |
3748 | if (!unlock) | |
3749 | if (read_trylock(&tasklist_lock)) | |
3750 | unlock = 1; | |
3751 | } while_each_thread(g, p); | |
3752 | ||
3753 | printk("\n"); | |
3754 | printk("=============================================\n\n"); | |
3755 | ||
3756 | if (unlock) | |
3757 | read_unlock(&tasklist_lock); | |
3758 | } | |
fbb9ce95 IM |
3759 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3760 | ||
82a1fcb9 IM |
3761 | /* |
3762 | * Careful: only use this function if you are sure that | |
3763 | * the task cannot run in parallel! | |
3764 | */ | |
3765 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3766 | { |
9c35dd7f JP |
3767 | if (unlikely(!debug_locks)) { |
3768 | printk("INFO: lockdep is turned off.\n"); | |
3769 | return; | |
3770 | } | |
fbb9ce95 IM |
3771 | lockdep_print_held_locks(task); |
3772 | } | |
82a1fcb9 IM |
3773 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3774 | ||
3775 | void debug_show_held_locks(struct task_struct *task) | |
3776 | { | |
3777 | __debug_show_held_locks(task); | |
3778 | } | |
fbb9ce95 | 3779 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3780 | |
3781 | void lockdep_sys_exit(void) | |
3782 | { | |
3783 | struct task_struct *curr = current; | |
3784 | ||
3785 | if (unlikely(curr->lockdep_depth)) { | |
3786 | if (!debug_locks_off()) | |
3787 | return; | |
3788 | printk("\n================================================\n"); | |
3789 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3790 | printk( "------------------------------------------------\n"); | |
3791 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3792 | curr->comm, curr->pid); | |
3793 | lockdep_print_held_locks(curr); | |
3794 | } | |
3795 | } |