Commit | Line | Data |
---|---|---|
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 |
67178767 | 52 | #include <trace/events/lock.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 | ||
3365e779 PZ |
145 | static inline u64 lockstat_clock(void) |
146 | { | |
147 | return cpu_clock(smp_processor_id()); | |
148 | } | |
149 | ||
c7e78cff | 150 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
151 | { |
152 | int i; | |
153 | ||
c7e78cff PZ |
154 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
155 | if (points[i] == 0) { | |
156 | points[i] = ip; | |
f20786ff PZ |
157 | break; |
158 | } | |
c7e78cff | 159 | if (points[i] == ip) |
f20786ff PZ |
160 | break; |
161 | } | |
162 | ||
163 | return i; | |
164 | } | |
165 | ||
3365e779 | 166 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
167 | { |
168 | if (time > lt->max) | |
169 | lt->max = time; | |
170 | ||
109d71c6 | 171 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
172 | lt->min = time; |
173 | ||
174 | lt->total += time; | |
175 | lt->nr++; | |
176 | } | |
177 | ||
c46261de PZ |
178 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
179 | { | |
109d71c6 FR |
180 | if (!src->nr) |
181 | return; | |
182 | ||
183 | if (src->max > dst->max) | |
184 | dst->max = src->max; | |
185 | ||
186 | if (src->min < dst->min || !dst->nr) | |
187 | dst->min = src->min; | |
188 | ||
c46261de PZ |
189 | dst->total += src->total; |
190 | dst->nr += src->nr; | |
191 | } | |
192 | ||
193 | struct lock_class_stats lock_stats(struct lock_class *class) | |
194 | { | |
195 | struct lock_class_stats stats; | |
196 | int cpu, i; | |
197 | ||
198 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
199 | for_each_possible_cpu(cpu) { | |
200 | struct lock_class_stats *pcs = | |
201 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
202 | ||
203 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
204 | stats.contention_point[i] += pcs->contention_point[i]; | |
205 | ||
c7e78cff PZ |
206 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
207 | stats.contending_point[i] += pcs->contending_point[i]; | |
208 | ||
c46261de PZ |
209 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
210 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
211 | ||
212 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
213 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
214 | |
215 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
216 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
217 | } |
218 | ||
219 | return stats; | |
220 | } | |
221 | ||
222 | void clear_lock_stats(struct lock_class *class) | |
223 | { | |
224 | int cpu; | |
225 | ||
226 | for_each_possible_cpu(cpu) { | |
227 | struct lock_class_stats *cpu_stats = | |
228 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
229 | ||
230 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
231 | } | |
232 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 233 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
234 | } |
235 | ||
f20786ff PZ |
236 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
237 | { | |
238 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
239 | } | |
240 | ||
241 | static void put_lock_stats(struct lock_class_stats *stats) | |
242 | { | |
243 | put_cpu_var(lock_stats); | |
244 | } | |
245 | ||
246 | static void lock_release_holdtime(struct held_lock *hlock) | |
247 | { | |
248 | struct lock_class_stats *stats; | |
3365e779 | 249 | u64 holdtime; |
f20786ff PZ |
250 | |
251 | if (!lock_stat) | |
252 | return; | |
253 | ||
3365e779 | 254 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 255 | |
f82b217e | 256 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
257 | if (hlock->read) |
258 | lock_time_inc(&stats->read_holdtime, holdtime); | |
259 | else | |
260 | lock_time_inc(&stats->write_holdtime, holdtime); | |
261 | put_lock_stats(stats); | |
262 | } | |
263 | #else | |
264 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
265 | { | |
266 | } | |
267 | #endif | |
268 | ||
fbb9ce95 IM |
269 | /* |
270 | * We keep a global list of all lock classes. The list only grows, | |
271 | * never shrinks. The list is only accessed with the lockdep | |
272 | * spinlock lock held. | |
273 | */ | |
274 | LIST_HEAD(all_lock_classes); | |
275 | ||
276 | /* | |
277 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
278 | */ | |
279 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
280 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 281 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
282 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
283 | ||
284 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
285 | ||
fbb9ce95 IM |
286 | /* |
287 | * We put the lock dependency chains into a hash-table as well, to cache | |
288 | * their existence: | |
289 | */ | |
290 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
291 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 292 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
293 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
294 | ||
295 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
296 | ||
297 | /* | |
298 | * The hash key of the lock dependency chains is a hash itself too: | |
299 | * it's a hash of all locks taken up to that lock, including that lock. | |
300 | * It's a 64-bit hash, because it's important for the keys to be | |
301 | * unique. | |
302 | */ | |
303 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
304 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
305 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
306 | (key2)) |
307 | ||
1d09daa5 | 308 | void lockdep_off(void) |
fbb9ce95 IM |
309 | { |
310 | current->lockdep_recursion++; | |
311 | } | |
fbb9ce95 IM |
312 | EXPORT_SYMBOL(lockdep_off); |
313 | ||
1d09daa5 | 314 | void lockdep_on(void) |
fbb9ce95 IM |
315 | { |
316 | current->lockdep_recursion--; | |
317 | } | |
fbb9ce95 IM |
318 | EXPORT_SYMBOL(lockdep_on); |
319 | ||
fbb9ce95 IM |
320 | /* |
321 | * Debugging switches: | |
322 | */ | |
323 | ||
324 | #define VERBOSE 0 | |
33e94e96 | 325 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
326 | |
327 | #if VERBOSE | |
328 | # define HARDIRQ_VERBOSE 1 | |
329 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 330 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
331 | #else |
332 | # define HARDIRQ_VERBOSE 0 | |
333 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 334 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
335 | #endif |
336 | ||
cf40bd16 | 337 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
338 | /* |
339 | * Quick filtering for interesting events: | |
340 | */ | |
341 | static int class_filter(struct lock_class *class) | |
342 | { | |
f9829cce AK |
343 | #if 0 |
344 | /* Example */ | |
fbb9ce95 | 345 | if (class->name_version == 1 && |
f9829cce | 346 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
347 | return 1; |
348 | if (class->name_version == 1 && | |
f9829cce | 349 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 350 | return 1; |
f9829cce | 351 | #endif |
a6640897 IM |
352 | /* Filter everything else. 1 would be to allow everything else */ |
353 | return 0; | |
fbb9ce95 IM |
354 | } |
355 | #endif | |
356 | ||
357 | static int verbose(struct lock_class *class) | |
358 | { | |
359 | #if VERBOSE | |
360 | return class_filter(class); | |
361 | #endif | |
362 | return 0; | |
363 | } | |
364 | ||
fbb9ce95 IM |
365 | /* |
366 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 367 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
368 | */ |
369 | unsigned long nr_stack_trace_entries; | |
370 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
371 | ||
372 | static int save_trace(struct stack_trace *trace) | |
373 | { | |
374 | trace->nr_entries = 0; | |
375 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
376 | trace->entries = stack_trace + nr_stack_trace_entries; | |
377 | ||
5a1b3999 | 378 | trace->skip = 3; |
5a1b3999 | 379 | |
ab1b6f03 | 380 | save_stack_trace(trace); |
fbb9ce95 | 381 | |
4f84f433 PZ |
382 | /* |
383 | * Some daft arches put -1 at the end to indicate its a full trace. | |
384 | * | |
385 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
386 | * complete trace that maxes out the entries provided will be reported | |
387 | * as incomplete, friggin useless </rant> | |
388 | */ | |
ea5b41f9 LT |
389 | if (trace->nr_entries != 0 && |
390 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
391 | trace->nr_entries--; |
392 | ||
fbb9ce95 IM |
393 | trace->max_entries = trace->nr_entries; |
394 | ||
395 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 396 | |
4f84f433 | 397 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
398 | if (!debug_locks_off_graph_unlock()) |
399 | return 0; | |
400 | ||
401 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
402 | printk("turning off the locking correctness validator.\n"); | |
403 | dump_stack(); | |
404 | ||
fbb9ce95 IM |
405 | return 0; |
406 | } | |
407 | ||
408 | return 1; | |
409 | } | |
410 | ||
411 | unsigned int nr_hardirq_chains; | |
412 | unsigned int nr_softirq_chains; | |
413 | unsigned int nr_process_chains; | |
414 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
415 | |
416 | #ifdef CONFIG_DEBUG_LOCKDEP | |
417 | /* | |
418 | * We cannot printk in early bootup code. Not even early_printk() | |
419 | * might work. So we mark any initialization errors and printk | |
420 | * about it later on, in lockdep_info(). | |
421 | */ | |
422 | static int lockdep_init_error; | |
c71063c9 JB |
423 | static unsigned long lockdep_init_trace_data[20]; |
424 | static struct stack_trace lockdep_init_trace = { | |
425 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
426 | .entries = lockdep_init_trace_data, | |
427 | }; | |
fbb9ce95 IM |
428 | |
429 | /* | |
430 | * Various lockdep statistics: | |
431 | */ | |
432 | atomic_t chain_lookup_hits; | |
433 | atomic_t chain_lookup_misses; | |
434 | atomic_t hardirqs_on_events; | |
435 | atomic_t hardirqs_off_events; | |
436 | atomic_t redundant_hardirqs_on; | |
437 | atomic_t redundant_hardirqs_off; | |
438 | atomic_t softirqs_on_events; | |
439 | atomic_t softirqs_off_events; | |
440 | atomic_t redundant_softirqs_on; | |
441 | atomic_t redundant_softirqs_off; | |
442 | atomic_t nr_unused_locks; | |
443 | atomic_t nr_cyclic_checks; | |
fbb9ce95 | 444 | atomic_t nr_find_usage_forwards_checks; |
fbb9ce95 | 445 | atomic_t nr_find_usage_backwards_checks; |
fbb9ce95 IM |
446 | #endif |
447 | ||
448 | /* | |
449 | * Locking printouts: | |
450 | */ | |
451 | ||
fabe9c42 | 452 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
453 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
454 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
455 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
456 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 457 | |
fbb9ce95 IM |
458 | static const char *usage_str[] = |
459 | { | |
fabe9c42 PZ |
460 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
461 | #include "lockdep_states.h" | |
462 | #undef LOCKDEP_STATE | |
463 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
464 | }; |
465 | ||
466 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
467 | { | |
ffb45122 | 468 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
469 | } |
470 | ||
3ff176ca | 471 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 472 | { |
3ff176ca PZ |
473 | return 1UL << bit; |
474 | } | |
fbb9ce95 | 475 | |
3ff176ca PZ |
476 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
477 | { | |
478 | char c = '.'; | |
479 | ||
480 | if (class->usage_mask & lock_flag(bit + 2)) | |
481 | c = '+'; | |
482 | if (class->usage_mask & lock_flag(bit)) { | |
483 | c = '-'; | |
484 | if (class->usage_mask & lock_flag(bit + 2)) | |
485 | c = '?'; | |
fbb9ce95 IM |
486 | } |
487 | ||
3ff176ca PZ |
488 | return c; |
489 | } | |
cf40bd16 | 490 | |
f510b233 | 491 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 492 | { |
f510b233 | 493 | int i = 0; |
cf40bd16 | 494 | |
f510b233 PZ |
495 | #define LOCKDEP_STATE(__STATE) \ |
496 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
497 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
498 | #include "lockdep_states.h" | |
499 | #undef LOCKDEP_STATE | |
500 | ||
501 | usage[i] = '\0'; | |
fbb9ce95 IM |
502 | } |
503 | ||
504 | static void print_lock_name(struct lock_class *class) | |
505 | { | |
f510b233 | 506 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
507 | const char *name; |
508 | ||
f510b233 | 509 | get_usage_chars(class, usage); |
fbb9ce95 IM |
510 | |
511 | name = class->name; | |
512 | if (!name) { | |
513 | name = __get_key_name(class->key, str); | |
514 | printk(" (%s", name); | |
515 | } else { | |
516 | printk(" (%s", name); | |
517 | if (class->name_version > 1) | |
518 | printk("#%d", class->name_version); | |
519 | if (class->subclass) | |
520 | printk("/%d", class->subclass); | |
521 | } | |
f510b233 | 522 | printk("){%s}", usage); |
fbb9ce95 IM |
523 | } |
524 | ||
525 | static void print_lockdep_cache(struct lockdep_map *lock) | |
526 | { | |
527 | const char *name; | |
9281acea | 528 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
529 | |
530 | name = lock->name; | |
531 | if (!name) | |
532 | name = __get_key_name(lock->key->subkeys, str); | |
533 | ||
534 | printk("%s", name); | |
535 | } | |
536 | ||
537 | static void print_lock(struct held_lock *hlock) | |
538 | { | |
f82b217e | 539 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
540 | printk(", at: "); |
541 | print_ip_sym(hlock->acquire_ip); | |
542 | } | |
543 | ||
544 | static void lockdep_print_held_locks(struct task_struct *curr) | |
545 | { | |
546 | int i, depth = curr->lockdep_depth; | |
547 | ||
548 | if (!depth) { | |
ba25f9dc | 549 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
550 | return; |
551 | } | |
552 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 553 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
554 | |
555 | for (i = 0; i < depth; i++) { | |
556 | printk(" #%d: ", i); | |
557 | print_lock(curr->held_locks + i); | |
558 | } | |
559 | } | |
fbb9ce95 | 560 | |
8e18257d PZ |
561 | static void print_kernel_version(void) |
562 | { | |
563 | printk("%s %.*s\n", init_utsname()->release, | |
564 | (int)strcspn(init_utsname()->version, " "), | |
565 | init_utsname()->version); | |
566 | } | |
567 | ||
568 | static int very_verbose(struct lock_class *class) | |
569 | { | |
570 | #if VERY_VERBOSE | |
571 | return class_filter(class); | |
572 | #endif | |
573 | return 0; | |
574 | } | |
575 | ||
fbb9ce95 | 576 | /* |
8e18257d | 577 | * Is this the address of a static object: |
fbb9ce95 | 578 | */ |
8e18257d | 579 | static int static_obj(void *obj) |
fbb9ce95 | 580 | { |
8e18257d PZ |
581 | unsigned long start = (unsigned long) &_stext, |
582 | end = (unsigned long) &_end, | |
583 | addr = (unsigned long) obj; | |
584 | #ifdef CONFIG_SMP | |
585 | int i; | |
586 | #endif | |
587 | ||
fbb9ce95 | 588 | /* |
8e18257d | 589 | * static variable? |
fbb9ce95 | 590 | */ |
8e18257d PZ |
591 | if ((addr >= start) && (addr < end)) |
592 | return 1; | |
fbb9ce95 | 593 | |
2a9ad18d MF |
594 | if (arch_is_kernel_data(addr)) |
595 | return 1; | |
596 | ||
8e18257d | 597 | #ifdef CONFIG_SMP |
fbb9ce95 | 598 | /* |
8e18257d | 599 | * percpu var? |
fbb9ce95 | 600 | */ |
8e18257d PZ |
601 | for_each_possible_cpu(i) { |
602 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
603 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
604 | + per_cpu_offset(i); | |
fbb9ce95 | 605 | |
8e18257d PZ |
606 | if ((addr >= start) && (addr < end)) |
607 | return 1; | |
608 | } | |
ca58abcb | 609 | #endif |
fbb9ce95 | 610 | |
8e18257d PZ |
611 | /* |
612 | * module var? | |
613 | */ | |
614 | return is_module_address(addr); | |
99de055a DJ |
615 | } |
616 | ||
fbb9ce95 | 617 | /* |
8e18257d PZ |
618 | * To make lock name printouts unique, we calculate a unique |
619 | * class->name_version generation counter: | |
fbb9ce95 | 620 | */ |
8e18257d | 621 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 622 | { |
8e18257d PZ |
623 | struct lock_class *class; |
624 | int count = 0; | |
fbb9ce95 | 625 | |
8e18257d | 626 | if (!new_class->name) |
fbb9ce95 IM |
627 | return 0; |
628 | ||
8e18257d PZ |
629 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
630 | if (new_class->key - new_class->subclass == class->key) | |
631 | return class->name_version; | |
632 | if (class->name && !strcmp(class->name, new_class->name)) | |
633 | count = max(count, class->name_version); | |
634 | } | |
fbb9ce95 | 635 | |
8e18257d | 636 | return count + 1; |
fbb9ce95 IM |
637 | } |
638 | ||
8e18257d PZ |
639 | /* |
640 | * Register a lock's class in the hash-table, if the class is not present | |
641 | * yet. Otherwise we look it up. We cache the result in the lock object | |
642 | * itself, so actual lookup of the hash should be once per lock object. | |
643 | */ | |
644 | static inline struct lock_class * | |
645 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 646 | { |
8e18257d PZ |
647 | struct lockdep_subclass_key *key; |
648 | struct list_head *hash_head; | |
649 | struct lock_class *class; | |
fbb9ce95 | 650 | |
8e18257d PZ |
651 | #ifdef CONFIG_DEBUG_LOCKDEP |
652 | /* | |
653 | * If the architecture calls into lockdep before initializing | |
654 | * the hashes then we'll warn about it later. (we cannot printk | |
655 | * right now) | |
656 | */ | |
657 | if (unlikely(!lockdep_initialized)) { | |
658 | lockdep_init(); | |
659 | lockdep_init_error = 1; | |
c71063c9 | 660 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
661 | } |
662 | #endif | |
fbb9ce95 | 663 | |
8e18257d PZ |
664 | /* |
665 | * Static locks do not have their class-keys yet - for them the key | |
666 | * is the lock object itself: | |
667 | */ | |
668 | if (unlikely(!lock->key)) | |
669 | lock->key = (void *)lock; | |
fbb9ce95 | 670 | |
8e18257d PZ |
671 | /* |
672 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
673 | * lock_class_key variable is passed in through the mutex_init() | |
674 | * (or spin_lock_init()) call - which acts as the key. For static | |
675 | * locks we use the lock object itself as the key. | |
676 | */ | |
4b32d0a4 PZ |
677 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
678 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 679 | |
8e18257d | 680 | key = lock->key->subkeys + subclass; |
ca268c69 | 681 | |
8e18257d | 682 | hash_head = classhashentry(key); |
74c383f1 | 683 | |
8e18257d PZ |
684 | /* |
685 | * We can walk the hash lockfree, because the hash only | |
686 | * grows, and we are careful when adding entries to the end: | |
687 | */ | |
4b32d0a4 PZ |
688 | list_for_each_entry(class, hash_head, hash_entry) { |
689 | if (class->key == key) { | |
690 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 691 | return class; |
4b32d0a4 PZ |
692 | } |
693 | } | |
fbb9ce95 | 694 | |
8e18257d | 695 | return NULL; |
fbb9ce95 IM |
696 | } |
697 | ||
698 | /* | |
8e18257d PZ |
699 | * Register a lock's class in the hash-table, if the class is not present |
700 | * yet. Otherwise we look it up. We cache the result in the lock object | |
701 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 702 | */ |
8e18257d PZ |
703 | static inline struct lock_class * |
704 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 705 | { |
8e18257d PZ |
706 | struct lockdep_subclass_key *key; |
707 | struct list_head *hash_head; | |
708 | struct lock_class *class; | |
709 | unsigned long flags; | |
710 | ||
711 | class = look_up_lock_class(lock, subclass); | |
712 | if (likely(class)) | |
713 | return class; | |
714 | ||
715 | /* | |
716 | * Debug-check: all keys must be persistent! | |
717 | */ | |
718 | if (!static_obj(lock->key)) { | |
719 | debug_locks_off(); | |
720 | printk("INFO: trying to register non-static key.\n"); | |
721 | printk("the code is fine but needs lockdep annotation.\n"); | |
722 | printk("turning off the locking correctness validator.\n"); | |
723 | dump_stack(); | |
724 | ||
725 | return NULL; | |
726 | } | |
727 | ||
728 | key = lock->key->subkeys + subclass; | |
729 | hash_head = classhashentry(key); | |
730 | ||
731 | raw_local_irq_save(flags); | |
732 | if (!graph_lock()) { | |
733 | raw_local_irq_restore(flags); | |
734 | return NULL; | |
735 | } | |
736 | /* | |
737 | * We have to do the hash-walk again, to avoid races | |
738 | * with another CPU: | |
739 | */ | |
740 | list_for_each_entry(class, hash_head, hash_entry) | |
741 | if (class->key == key) | |
742 | goto out_unlock_set; | |
743 | /* | |
744 | * Allocate a new key from the static array, and add it to | |
745 | * the hash: | |
746 | */ | |
747 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
748 | if (!debug_locks_off_graph_unlock()) { | |
749 | raw_local_irq_restore(flags); | |
750 | return NULL; | |
751 | } | |
752 | raw_local_irq_restore(flags); | |
753 | ||
754 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
755 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 756 | dump_stack(); |
8e18257d PZ |
757 | return NULL; |
758 | } | |
759 | class = lock_classes + nr_lock_classes++; | |
760 | debug_atomic_inc(&nr_unused_locks); | |
761 | class->key = key; | |
762 | class->name = lock->name; | |
763 | class->subclass = subclass; | |
764 | INIT_LIST_HEAD(&class->lock_entry); | |
765 | INIT_LIST_HEAD(&class->locks_before); | |
766 | INIT_LIST_HEAD(&class->locks_after); | |
767 | class->name_version = count_matching_names(class); | |
768 | /* | |
769 | * We use RCU's safe list-add method to make | |
770 | * parallel walking of the hash-list safe: | |
771 | */ | |
772 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
773 | /* |
774 | * Add it to the global list of classes: | |
775 | */ | |
776 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
777 | |
778 | if (verbose(class)) { | |
779 | graph_unlock(); | |
780 | raw_local_irq_restore(flags); | |
781 | ||
782 | printk("\nnew class %p: %s", class->key, class->name); | |
783 | if (class->name_version > 1) | |
784 | printk("#%d", class->name_version); | |
785 | printk("\n"); | |
786 | dump_stack(); | |
787 | ||
788 | raw_local_irq_save(flags); | |
789 | if (!graph_lock()) { | |
790 | raw_local_irq_restore(flags); | |
791 | return NULL; | |
792 | } | |
793 | } | |
794 | out_unlock_set: | |
795 | graph_unlock(); | |
796 | raw_local_irq_restore(flags); | |
797 | ||
798 | if (!subclass || force) | |
799 | lock->class_cache = class; | |
800 | ||
801 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
802 | return NULL; | |
803 | ||
804 | return class; | |
805 | } | |
806 | ||
807 | #ifdef CONFIG_PROVE_LOCKING | |
808 | /* | |
809 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
810 | * with NULL on failure) | |
811 | */ | |
812 | static struct lock_list *alloc_list_entry(void) | |
813 | { | |
814 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
815 | if (!debug_locks_off_graph_unlock()) | |
816 | return NULL; | |
817 | ||
818 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
819 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 820 | dump_stack(); |
8e18257d PZ |
821 | return NULL; |
822 | } | |
823 | return list_entries + nr_list_entries++; | |
824 | } | |
825 | ||
826 | /* | |
827 | * Add a new dependency to the head of the list: | |
828 | */ | |
829 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
830 | struct list_head *head, unsigned long ip, int distance) | |
831 | { | |
832 | struct lock_list *entry; | |
833 | /* | |
834 | * Lock not present yet - get a new dependency struct and | |
835 | * add it to the list: | |
836 | */ | |
837 | entry = alloc_list_entry(); | |
838 | if (!entry) | |
839 | return 0; | |
840 | ||
8e18257d PZ |
841 | if (!save_trace(&entry->trace)) |
842 | return 0; | |
843 | ||
74870172 ZY |
844 | entry->class = this; |
845 | entry->distance = distance; | |
8e18257d PZ |
846 | /* |
847 | * Since we never remove from the dependency list, the list can | |
848 | * be walked lockless by other CPUs, it's only allocation | |
849 | * that must be protected by the spinlock. But this also means | |
850 | * we must make new entries visible only once writes to the | |
851 | * entry become visible - hence the RCU op: | |
852 | */ | |
853 | list_add_tail_rcu(&entry->entry, head); | |
854 | ||
855 | return 1; | |
856 | } | |
857 | ||
98c33edd PZ |
858 | /* |
859 | * For good efficiency of modular, we use power of 2 | |
860 | */ | |
af012961 PZ |
861 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
862 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
863 | ||
98c33edd PZ |
864 | /* |
865 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
866 | * breadth-first search(BFS)algorithem, by which we can build |
867 | * the shortest path from the next lock to be acquired to the | |
868 | * previous held lock if there is a circular between them. | |
98c33edd | 869 | */ |
af012961 PZ |
870 | struct circular_queue { |
871 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
872 | unsigned int front, rear; | |
873 | }; | |
874 | ||
875 | static struct circular_queue lock_cq; | |
af012961 | 876 | |
12f3dfd0 | 877 | unsigned int max_bfs_queue_depth; |
af012961 | 878 | |
e351b660 ML |
879 | static unsigned int lockdep_dependency_gen_id; |
880 | ||
af012961 PZ |
881 | static inline void __cq_init(struct circular_queue *cq) |
882 | { | |
883 | cq->front = cq->rear = 0; | |
e351b660 | 884 | lockdep_dependency_gen_id++; |
af012961 PZ |
885 | } |
886 | ||
887 | static inline int __cq_empty(struct circular_queue *cq) | |
888 | { | |
889 | return (cq->front == cq->rear); | |
890 | } | |
891 | ||
892 | static inline int __cq_full(struct circular_queue *cq) | |
893 | { | |
894 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
895 | } | |
896 | ||
897 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
898 | { | |
899 | if (__cq_full(cq)) | |
900 | return -1; | |
901 | ||
902 | cq->element[cq->rear] = elem; | |
903 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
904 | return 0; | |
905 | } | |
906 | ||
907 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
908 | { | |
909 | if (__cq_empty(cq)) | |
910 | return -1; | |
911 | ||
912 | *elem = cq->element[cq->front]; | |
913 | cq->front = (cq->front + 1) & CQ_MASK; | |
914 | return 0; | |
915 | } | |
916 | ||
917 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
918 | { | |
919 | return (cq->rear - cq->front) & CQ_MASK; | |
920 | } | |
921 | ||
922 | static inline void mark_lock_accessed(struct lock_list *lock, | |
923 | struct lock_list *parent) | |
924 | { | |
925 | unsigned long nr; | |
98c33edd | 926 | |
af012961 PZ |
927 | nr = lock - list_entries; |
928 | WARN_ON(nr >= nr_list_entries); | |
929 | lock->parent = parent; | |
e351b660 | 930 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
931 | } |
932 | ||
933 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
934 | { | |
935 | unsigned long nr; | |
98c33edd | 936 | |
af012961 PZ |
937 | nr = lock - list_entries; |
938 | WARN_ON(nr >= nr_list_entries); | |
e351b660 | 939 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
940 | } |
941 | ||
942 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
943 | { | |
944 | return child->parent; | |
945 | } | |
946 | ||
947 | static inline int get_lock_depth(struct lock_list *child) | |
948 | { | |
949 | int depth = 0; | |
950 | struct lock_list *parent; | |
951 | ||
952 | while ((parent = get_lock_parent(child))) { | |
953 | child = parent; | |
954 | depth++; | |
955 | } | |
956 | return depth; | |
957 | } | |
958 | ||
9e2d551e | 959 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
960 | void *data, |
961 | int (*match)(struct lock_list *entry, void *data), | |
962 | struct lock_list **target_entry, | |
963 | int forward) | |
c94aa5ca ML |
964 | { |
965 | struct lock_list *entry; | |
d588e461 | 966 | struct list_head *head; |
c94aa5ca ML |
967 | struct circular_queue *cq = &lock_cq; |
968 | int ret = 1; | |
969 | ||
9e2d551e | 970 | if (match(source_entry, data)) { |
c94aa5ca ML |
971 | *target_entry = source_entry; |
972 | ret = 0; | |
973 | goto exit; | |
974 | } | |
975 | ||
d588e461 ML |
976 | if (forward) |
977 | head = &source_entry->class->locks_after; | |
978 | else | |
979 | head = &source_entry->class->locks_before; | |
980 | ||
981 | if (list_empty(head)) | |
982 | goto exit; | |
983 | ||
984 | __cq_init(cq); | |
c94aa5ca ML |
985 | __cq_enqueue(cq, (unsigned long)source_entry); |
986 | ||
987 | while (!__cq_empty(cq)) { | |
988 | struct lock_list *lock; | |
c94aa5ca ML |
989 | |
990 | __cq_dequeue(cq, (unsigned long *)&lock); | |
991 | ||
992 | if (!lock->class) { | |
993 | ret = -2; | |
994 | goto exit; | |
995 | } | |
996 | ||
997 | if (forward) | |
998 | head = &lock->class->locks_after; | |
999 | else | |
1000 | head = &lock->class->locks_before; | |
1001 | ||
1002 | list_for_each_entry(entry, head, entry) { | |
1003 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 1004 | unsigned int cq_depth; |
c94aa5ca | 1005 | mark_lock_accessed(entry, lock); |
9e2d551e | 1006 | if (match(entry, data)) { |
c94aa5ca ML |
1007 | *target_entry = entry; |
1008 | ret = 0; | |
1009 | goto exit; | |
1010 | } | |
1011 | ||
1012 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1013 | ret = -1; | |
1014 | goto exit; | |
1015 | } | |
12f3dfd0 ML |
1016 | cq_depth = __cq_get_elem_count(cq); |
1017 | if (max_bfs_queue_depth < cq_depth) | |
1018 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1019 | } |
1020 | } | |
1021 | } | |
1022 | exit: | |
1023 | return ret; | |
1024 | } | |
1025 | ||
d7aaba14 | 1026 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1027 | void *data, |
1028 | int (*match)(struct lock_list *entry, void *data), | |
1029 | struct lock_list **target_entry) | |
c94aa5ca | 1030 | { |
9e2d551e | 1031 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1032 | |
1033 | } | |
1034 | ||
d7aaba14 | 1035 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1036 | void *data, |
1037 | int (*match)(struct lock_list *entry, void *data), | |
1038 | struct lock_list **target_entry) | |
c94aa5ca | 1039 | { |
9e2d551e | 1040 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1041 | |
1042 | } | |
1043 | ||
8e18257d PZ |
1044 | /* |
1045 | * Recursive, forwards-direction lock-dependency checking, used for | |
1046 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1047 | * checking. | |
8e18257d | 1048 | */ |
8e18257d PZ |
1049 | |
1050 | /* | |
1051 | * Print a dependency chain entry (this is only done when a deadlock | |
1052 | * has been detected): | |
1053 | */ | |
1054 | static noinline int | |
24208ca7 | 1055 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1056 | { |
1057 | if (debug_locks_silent) | |
1058 | return 0; | |
1059 | printk("\n-> #%u", depth); | |
1060 | print_lock_name(target->class); | |
1061 | printk(":\n"); | |
1062 | print_stack_trace(&target->trace, 6); | |
1063 | ||
1064 | return 0; | |
1065 | } | |
1066 | ||
1067 | /* | |
1068 | * When a circular dependency is detected, print the | |
1069 | * header first: | |
1070 | */ | |
1071 | static noinline int | |
db0002a3 ML |
1072 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1073 | struct held_lock *check_src, | |
1074 | struct held_lock *check_tgt) | |
8e18257d PZ |
1075 | { |
1076 | struct task_struct *curr = current; | |
1077 | ||
c94aa5ca | 1078 | if (debug_locks_silent) |
8e18257d PZ |
1079 | return 0; |
1080 | ||
1081 | printk("\n=======================================================\n"); | |
1082 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1083 | print_kernel_version(); | |
1084 | printk( "-------------------------------------------------------\n"); | |
1085 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1086 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1087 | print_lock(check_src); |
8e18257d | 1088 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1089 | print_lock(check_tgt); |
8e18257d PZ |
1090 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1091 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1092 | ||
1093 | print_circular_bug_entry(entry, depth); | |
1094 | ||
1095 | return 0; | |
1096 | } | |
1097 | ||
9e2d551e ML |
1098 | static inline int class_equal(struct lock_list *entry, void *data) |
1099 | { | |
1100 | return entry->class == data; | |
1101 | } | |
1102 | ||
db0002a3 ML |
1103 | static noinline int print_circular_bug(struct lock_list *this, |
1104 | struct lock_list *target, | |
1105 | struct held_lock *check_src, | |
1106 | struct held_lock *check_tgt) | |
8e18257d PZ |
1107 | { |
1108 | struct task_struct *curr = current; | |
c94aa5ca | 1109 | struct lock_list *parent; |
24208ca7 | 1110 | int depth; |
8e18257d | 1111 | |
c94aa5ca | 1112 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1113 | return 0; |
1114 | ||
db0002a3 | 1115 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1116 | return 0; |
1117 | ||
c94aa5ca ML |
1118 | depth = get_lock_depth(target); |
1119 | ||
db0002a3 | 1120 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1121 | |
1122 | parent = get_lock_parent(target); | |
1123 | ||
1124 | while (parent) { | |
1125 | print_circular_bug_entry(parent, --depth); | |
1126 | parent = get_lock_parent(parent); | |
1127 | } | |
8e18257d PZ |
1128 | |
1129 | printk("\nother info that might help us debug this:\n\n"); | |
1130 | lockdep_print_held_locks(curr); | |
1131 | ||
1132 | printk("\nstack backtrace:\n"); | |
1133 | dump_stack(); | |
1134 | ||
1135 | return 0; | |
1136 | } | |
1137 | ||
db0002a3 ML |
1138 | static noinline int print_bfs_bug(int ret) |
1139 | { | |
1140 | if (!debug_locks_off_graph_unlock()) | |
1141 | return 0; | |
1142 | ||
1143 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1144 | ||
1145 | return 0; | |
1146 | } | |
1147 | ||
ef681026 | 1148 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1149 | { |
ef681026 ML |
1150 | (*(unsigned long *)data)++; |
1151 | return 0; | |
1152 | } | |
419ca3f1 | 1153 | |
ef681026 ML |
1154 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1155 | { | |
1156 | unsigned long count = 0; | |
1157 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1158 | |
ef681026 | 1159 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1160 | |
ef681026 | 1161 | return count; |
419ca3f1 | 1162 | } |
419ca3f1 DM |
1163 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1164 | { | |
1165 | unsigned long ret, flags; | |
ef681026 ML |
1166 | struct lock_list this; |
1167 | ||
1168 | this.parent = NULL; | |
1169 | this.class = class; | |
419ca3f1 DM |
1170 | |
1171 | local_irq_save(flags); | |
1172 | __raw_spin_lock(&lockdep_lock); | |
ef681026 | 1173 | ret = __lockdep_count_forward_deps(&this); |
419ca3f1 DM |
1174 | __raw_spin_unlock(&lockdep_lock); |
1175 | local_irq_restore(flags); | |
1176 | ||
1177 | return ret; | |
1178 | } | |
1179 | ||
ef681026 | 1180 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1181 | { |
ef681026 ML |
1182 | unsigned long count = 0; |
1183 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1184 | |
ef681026 | 1185 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1186 | |
ef681026 | 1187 | return count; |
419ca3f1 DM |
1188 | } |
1189 | ||
1190 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1191 | { | |
1192 | unsigned long ret, flags; | |
ef681026 ML |
1193 | struct lock_list this; |
1194 | ||
1195 | this.parent = NULL; | |
1196 | this.class = class; | |
419ca3f1 DM |
1197 | |
1198 | local_irq_save(flags); | |
1199 | __raw_spin_lock(&lockdep_lock); | |
ef681026 | 1200 | ret = __lockdep_count_backward_deps(&this); |
419ca3f1 DM |
1201 | __raw_spin_unlock(&lockdep_lock); |
1202 | local_irq_restore(flags); | |
1203 | ||
1204 | return ret; | |
1205 | } | |
1206 | ||
8e18257d PZ |
1207 | /* |
1208 | * Prove that the dependency graph starting at <entry> can not | |
1209 | * lead to <target>. Print an error and return 0 if it does. | |
1210 | */ | |
1211 | static noinline int | |
db0002a3 ML |
1212 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1213 | struct lock_list **target_entry) | |
8e18257d | 1214 | { |
db0002a3 | 1215 | int result; |
8e18257d | 1216 | |
db0002a3 | 1217 | debug_atomic_inc(&nr_cyclic_checks); |
419ca3f1 | 1218 | |
d7aaba14 | 1219 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1220 | |
db0002a3 ML |
1221 | return result; |
1222 | } | |
c94aa5ca | 1223 | |
81d68a96 | 1224 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1225 | /* |
1226 | * Forwards and backwards subgraph searching, for the purposes of | |
1227 | * proving that two subgraphs can be connected by a new dependency | |
1228 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1229 | */ | |
fbb9ce95 | 1230 | |
d7aaba14 ML |
1231 | static inline int usage_match(struct lock_list *entry, void *bit) |
1232 | { | |
1233 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1234 | } | |
1235 | ||
1236 | ||
1237 | ||
fbb9ce95 IM |
1238 | /* |
1239 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1240 | * at @root->class that matches @bit. |
fbb9ce95 | 1241 | * |
d7aaba14 ML |
1242 | * Return 0 if such a node exists in the subgraph, and put that node |
1243 | * into *@target_entry. | |
fbb9ce95 | 1244 | * |
d7aaba14 ML |
1245 | * Return 1 otherwise and keep *@target_entry unchanged. |
1246 | * Return <0 on error. | |
fbb9ce95 | 1247 | */ |
d7aaba14 ML |
1248 | static int |
1249 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1250 | struct lock_list **target_entry) | |
fbb9ce95 | 1251 | { |
d7aaba14 | 1252 | int result; |
fbb9ce95 IM |
1253 | |
1254 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
fbb9ce95 | 1255 | |
d7aaba14 ML |
1256 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1257 | ||
1258 | return result; | |
fbb9ce95 IM |
1259 | } |
1260 | ||
1261 | /* | |
1262 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1263 | * at @root->class that matches @bit. |
fbb9ce95 | 1264 | * |
d7aaba14 ML |
1265 | * Return 0 if such a node exists in the subgraph, and put that node |
1266 | * into *@target_entry. | |
fbb9ce95 | 1267 | * |
d7aaba14 ML |
1268 | * Return 1 otherwise and keep *@target_entry unchanged. |
1269 | * Return <0 on error. | |
fbb9ce95 | 1270 | */ |
d7aaba14 ML |
1271 | static int |
1272 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1273 | struct lock_list **target_entry) | |
fbb9ce95 | 1274 | { |
d7aaba14 | 1275 | int result; |
fbb9ce95 IM |
1276 | |
1277 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
fbb9ce95 | 1278 | |
d7aaba14 | 1279 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1280 | |
d7aaba14 | 1281 | return result; |
fbb9ce95 IM |
1282 | } |
1283 | ||
af012961 PZ |
1284 | static void print_lock_class_header(struct lock_class *class, int depth) |
1285 | { | |
1286 | int bit; | |
1287 | ||
1288 | printk("%*s->", depth, ""); | |
1289 | print_lock_name(class); | |
1290 | printk(" ops: %lu", class->ops); | |
1291 | printk(" {\n"); | |
1292 | ||
1293 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1294 | if (class->usage_mask & (1 << bit)) { | |
1295 | int len = depth; | |
1296 | ||
1297 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1298 | len += printk(" at:\n"); | |
1299 | print_stack_trace(class->usage_traces + bit, len); | |
1300 | } | |
1301 | } | |
1302 | printk("%*s }\n", depth, ""); | |
1303 | ||
1304 | printk("%*s ... key at: ",depth,""); | |
1305 | print_ip_sym((unsigned long)class->key); | |
1306 | } | |
1307 | ||
1308 | /* | |
1309 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1310 | */ | |
1311 | static void __used | |
1312 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1313 | struct lock_list *root) | |
1314 | { | |
1315 | struct lock_list *entry = leaf; | |
1316 | int depth; | |
1317 | ||
1318 | /*compute depth from generated tree by BFS*/ | |
1319 | depth = get_lock_depth(leaf); | |
1320 | ||
1321 | do { | |
1322 | print_lock_class_header(entry->class, depth); | |
1323 | printk("%*s ... acquired at:\n", depth, ""); | |
1324 | print_stack_trace(&entry->trace, 2); | |
1325 | printk("\n"); | |
1326 | ||
1327 | if (depth == 0 && (entry != root)) { | |
1328 | printk("lockdep:%s bad BFS generated tree\n", __func__); | |
1329 | break; | |
1330 | } | |
1331 | ||
1332 | entry = get_lock_parent(entry); | |
1333 | depth--; | |
1334 | } while (entry && (depth >= 0)); | |
1335 | ||
1336 | return; | |
1337 | } | |
d7aaba14 | 1338 | |
fbb9ce95 IM |
1339 | static int |
1340 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1341 | struct lock_list *prev_root, |
1342 | struct lock_list *next_root, | |
1343 | struct lock_list *backwards_entry, | |
1344 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1345 | struct held_lock *prev, |
1346 | struct held_lock *next, | |
1347 | enum lock_usage_bit bit1, | |
1348 | enum lock_usage_bit bit2, | |
1349 | const char *irqclass) | |
1350 | { | |
74c383f1 | 1351 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1352 | return 0; |
1353 | ||
1354 | printk("\n======================================================\n"); | |
1355 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1356 | irqclass, irqclass); | |
99de055a | 1357 | print_kernel_version(); |
fbb9ce95 IM |
1358 | printk( "------------------------------------------------------\n"); |
1359 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1360 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1361 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1362 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1363 | curr->hardirqs_enabled, | |
1364 | curr->softirqs_enabled); | |
1365 | print_lock(next); | |
1366 | ||
1367 | printk("\nand this task is already holding:\n"); | |
1368 | print_lock(prev); | |
1369 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1370 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1371 | printk(" ->"); |
f82b217e | 1372 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1373 | printk("\n"); |
1374 | ||
1375 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1376 | irqclass); | |
24208ca7 | 1377 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1378 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1379 | ||
24208ca7 | 1380 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1381 | |
1382 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1383 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1384 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1385 | printk("..."); | |
1386 | ||
24208ca7 | 1387 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1388 | |
1389 | printk("\nother info that might help us debug this:\n\n"); | |
1390 | lockdep_print_held_locks(curr); | |
1391 | ||
24208ca7 ML |
1392 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1393 | printk(" and the holding lock:\n"); | |
1394 | if (!save_trace(&prev_root->trace)) | |
1395 | return 0; | |
1396 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1397 | |
24208ca7 ML |
1398 | printk("\nthe dependencies between the lock to be acquired"); |
1399 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1400 | if (!save_trace(&next_root->trace)) | |
1401 | return 0; | |
1402 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1403 | |
1404 | printk("\nstack backtrace:\n"); | |
1405 | dump_stack(); | |
1406 | ||
1407 | return 0; | |
1408 | } | |
1409 | ||
1410 | static int | |
1411 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1412 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1413 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1414 | { | |
1415 | int ret; | |
24208ca7 | 1416 | struct lock_list this, that; |
d7aaba14 | 1417 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1418 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1419 | |
1420 | this.parent = NULL; | |
1421 | ||
1422 | this.class = hlock_class(prev); | |
1423 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1424 | if (ret < 0) |
1425 | return print_bfs_bug(ret); | |
1426 | if (ret == 1) | |
1427 | return ret; | |
d7aaba14 | 1428 | |
24208ca7 ML |
1429 | that.parent = NULL; |
1430 | that.class = hlock_class(next); | |
1431 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1432 | if (ret < 0) |
1433 | return print_bfs_bug(ret); | |
1434 | if (ret == 1) | |
1435 | return ret; | |
fbb9ce95 | 1436 | |
24208ca7 ML |
1437 | return print_bad_irq_dependency(curr, &this, &that, |
1438 | target_entry, target_entry1, | |
1439 | prev, next, | |
fbb9ce95 IM |
1440 | bit_backwards, bit_forwards, irqclass); |
1441 | } | |
1442 | ||
4f367d8a PZ |
1443 | static const char *state_names[] = { |
1444 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1445 | __stringify(__STATE), |
4f367d8a PZ |
1446 | #include "lockdep_states.h" |
1447 | #undef LOCKDEP_STATE | |
1448 | }; | |
1449 | ||
1450 | static const char *state_rnames[] = { | |
1451 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1452 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1453 | #include "lockdep_states.h" |
1454 | #undef LOCKDEP_STATE | |
1455 | }; | |
1456 | ||
1457 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1458 | { |
4f367d8a PZ |
1459 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1460 | } | |
8e18257d | 1461 | |
4f367d8a PZ |
1462 | static int exclusive_bit(int new_bit) |
1463 | { | |
8e18257d | 1464 | /* |
4f367d8a PZ |
1465 | * USED_IN |
1466 | * USED_IN_READ | |
1467 | * ENABLED | |
1468 | * ENABLED_READ | |
1469 | * | |
1470 | * bit 0 - write/read | |
1471 | * bit 1 - used_in/enabled | |
1472 | * bit 2+ state | |
8e18257d | 1473 | */ |
4f367d8a PZ |
1474 | |
1475 | int state = new_bit & ~3; | |
1476 | int dir = new_bit & 2; | |
8e18257d PZ |
1477 | |
1478 | /* | |
4f367d8a | 1479 | * keep state, bit flip the direction and strip read. |
8e18257d | 1480 | */ |
4f367d8a PZ |
1481 | return state | (dir ^ 2); |
1482 | } | |
1483 | ||
1484 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1485 | struct held_lock *next, enum lock_usage_bit bit) | |
1486 | { | |
8e18257d | 1487 | /* |
4f367d8a PZ |
1488 | * Prove that the new dependency does not connect a hardirq-safe |
1489 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1490 | * the backwards-subgraph starting at <prev>, and the |
1491 | * forwards-subgraph starting at <next>: | |
1492 | */ | |
4f367d8a PZ |
1493 | if (!check_usage(curr, prev, next, bit, |
1494 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1495 | return 0; |
1496 | ||
4f367d8a PZ |
1497 | bit++; /* _READ */ |
1498 | ||
cf40bd16 | 1499 | /* |
4f367d8a PZ |
1500 | * Prove that the new dependency does not connect a hardirq-safe-read |
1501 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1502 | * the backwards-subgraph starting at <prev>, and the |
1503 | * forwards-subgraph starting at <next>: | |
1504 | */ | |
4f367d8a PZ |
1505 | if (!check_usage(curr, prev, next, bit, |
1506 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1507 | return 0; |
1508 | ||
4f367d8a PZ |
1509 | return 1; |
1510 | } | |
1511 | ||
1512 | static int | |
1513 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1514 | struct held_lock *next) | |
1515 | { | |
1516 | #define LOCKDEP_STATE(__STATE) \ | |
1517 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1518 | return 0; |
4f367d8a PZ |
1519 | #include "lockdep_states.h" |
1520 | #undef LOCKDEP_STATE | |
cf40bd16 | 1521 | |
8e18257d PZ |
1522 | return 1; |
1523 | } | |
1524 | ||
1525 | static void inc_chains(void) | |
1526 | { | |
1527 | if (current->hardirq_context) | |
1528 | nr_hardirq_chains++; | |
1529 | else { | |
1530 | if (current->softirq_context) | |
1531 | nr_softirq_chains++; | |
1532 | else | |
1533 | nr_process_chains++; | |
1534 | } | |
1535 | } | |
1536 | ||
1537 | #else | |
1538 | ||
1539 | static inline int | |
1540 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1541 | struct held_lock *next) | |
1542 | { | |
1543 | return 1; | |
1544 | } | |
1545 | ||
1546 | static inline void inc_chains(void) | |
1547 | { | |
1548 | nr_process_chains++; | |
1549 | } | |
1550 | ||
fbb9ce95 IM |
1551 | #endif |
1552 | ||
1553 | static int | |
1554 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1555 | struct held_lock *next) | |
1556 | { | |
74c383f1 | 1557 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1558 | return 0; |
1559 | ||
1560 | printk("\n=============================================\n"); | |
1561 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1562 | print_kernel_version(); |
fbb9ce95 IM |
1563 | printk( "---------------------------------------------\n"); |
1564 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1565 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1566 | print_lock(next); |
1567 | printk("\nbut task is already holding lock:\n"); | |
1568 | print_lock(prev); | |
1569 | ||
1570 | printk("\nother info that might help us debug this:\n"); | |
1571 | lockdep_print_held_locks(curr); | |
1572 | ||
1573 | printk("\nstack backtrace:\n"); | |
1574 | dump_stack(); | |
1575 | ||
1576 | return 0; | |
1577 | } | |
1578 | ||
1579 | /* | |
1580 | * Check whether we are holding such a class already. | |
1581 | * | |
1582 | * (Note that this has to be done separately, because the graph cannot | |
1583 | * detect such classes of deadlocks.) | |
1584 | * | |
1585 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1586 | */ | |
1587 | static int | |
1588 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1589 | struct lockdep_map *next_instance, int read) | |
1590 | { | |
1591 | struct held_lock *prev; | |
7531e2f3 | 1592 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1593 | int i; |
1594 | ||
1595 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1596 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1597 | |
1598 | if (prev->instance == next->nest_lock) | |
1599 | nest = prev; | |
1600 | ||
f82b217e | 1601 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1602 | continue; |
7531e2f3 | 1603 | |
fbb9ce95 IM |
1604 | /* |
1605 | * Allow read-after-read recursion of the same | |
6c9076ec | 1606 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1607 | */ |
6c9076ec | 1608 | if ((read == 2) && prev->read) |
fbb9ce95 | 1609 | return 2; |
7531e2f3 PZ |
1610 | |
1611 | /* | |
1612 | * We're holding the nest_lock, which serializes this lock's | |
1613 | * nesting behaviour. | |
1614 | */ | |
1615 | if (nest) | |
1616 | return 2; | |
1617 | ||
fbb9ce95 IM |
1618 | return print_deadlock_bug(curr, prev, next); |
1619 | } | |
1620 | return 1; | |
1621 | } | |
1622 | ||
1623 | /* | |
1624 | * There was a chain-cache miss, and we are about to add a new dependency | |
1625 | * to a previous lock. We recursively validate the following rules: | |
1626 | * | |
1627 | * - would the adding of the <prev> -> <next> dependency create a | |
1628 | * circular dependency in the graph? [== circular deadlock] | |
1629 | * | |
1630 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1631 | * (in the full backwards-subgraph starting at <prev>) with any | |
1632 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1633 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1634 | * | |
1635 | * - does the new prev->next dependency connect any softirq-safe lock | |
1636 | * (in the full backwards-subgraph starting at <prev>) with any | |
1637 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1638 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1639 | * | |
1640 | * any of these scenarios could lead to a deadlock. | |
1641 | * | |
1642 | * Then if all the validations pass, we add the forwards and backwards | |
1643 | * dependency. | |
1644 | */ | |
1645 | static int | |
1646 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1647 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1648 | { |
1649 | struct lock_list *entry; | |
1650 | int ret; | |
db0002a3 ML |
1651 | struct lock_list this; |
1652 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 IM |
1653 | |
1654 | /* | |
1655 | * Prove that the new <prev> -> <next> dependency would not | |
1656 | * create a circular dependency in the graph. (We do this by | |
1657 | * forward-recursing into the graph starting at <next>, and | |
1658 | * checking whether we can reach <prev>.) | |
1659 | * | |
1660 | * We are using global variables to control the recursion, to | |
1661 | * keep the stackframe size of the recursive functions low: | |
1662 | */ | |
db0002a3 ML |
1663 | this.class = hlock_class(next); |
1664 | this.parent = NULL; | |
1665 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1666 | if (unlikely(!ret)) | |
1667 | return print_circular_bug(&this, target_entry, next, prev); | |
1668 | else if (unlikely(ret < 0)) | |
1669 | return print_bfs_bug(ret); | |
c94aa5ca | 1670 | |
8e18257d | 1671 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1672 | return 0; |
1673 | ||
fbb9ce95 IM |
1674 | /* |
1675 | * For recursive read-locks we do all the dependency checks, | |
1676 | * but we dont store read-triggered dependencies (only | |
1677 | * write-triggered dependencies). This ensures that only the | |
1678 | * write-side dependencies matter, and that if for example a | |
1679 | * write-lock never takes any other locks, then the reads are | |
1680 | * equivalent to a NOP. | |
1681 | */ | |
1682 | if (next->read == 2 || prev->read == 2) | |
1683 | return 1; | |
1684 | /* | |
1685 | * Is the <prev> -> <next> dependency already present? | |
1686 | * | |
1687 | * (this may occur even though this is a new chain: consider | |
1688 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1689 | * chains - the second one will be new, but L1 already has | |
1690 | * L2 added to its dependency list, due to the first chain.) | |
1691 | */ | |
f82b217e DJ |
1692 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1693 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1694 | if (distance == 1) |
1695 | entry->distance = 1; | |
fbb9ce95 | 1696 | return 2; |
068135e6 | 1697 | } |
fbb9ce95 IM |
1698 | } |
1699 | ||
1700 | /* | |
1701 | * Ok, all validations passed, add the new lock | |
1702 | * to the previous lock's dependency list: | |
1703 | */ | |
f82b217e DJ |
1704 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1705 | &hlock_class(prev)->locks_after, | |
1706 | next->acquire_ip, distance); | |
068135e6 | 1707 | |
fbb9ce95 IM |
1708 | if (!ret) |
1709 | return 0; | |
910b1b2e | 1710 | |
f82b217e DJ |
1711 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1712 | &hlock_class(next)->locks_before, | |
1713 | next->acquire_ip, distance); | |
910b1b2e JP |
1714 | if (!ret) |
1715 | return 0; | |
fbb9ce95 IM |
1716 | |
1717 | /* | |
8e18257d PZ |
1718 | * Debugging printouts: |
1719 | */ | |
f82b217e | 1720 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1721 | graph_unlock(); |
1722 | printk("\n new dependency: "); | |
f82b217e | 1723 | print_lock_name(hlock_class(prev)); |
8e18257d | 1724 | printk(" => "); |
f82b217e | 1725 | print_lock_name(hlock_class(next)); |
8e18257d | 1726 | printk("\n"); |
fbb9ce95 | 1727 | dump_stack(); |
8e18257d | 1728 | return graph_lock(); |
fbb9ce95 | 1729 | } |
8e18257d PZ |
1730 | return 1; |
1731 | } | |
fbb9ce95 | 1732 | |
8e18257d PZ |
1733 | /* |
1734 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1735 | * The ones that are relevant are (in increasing distance from curr): | |
1736 | * all consecutive trylock entries and the final non-trylock entry - or | |
1737 | * the end of this context's lock-chain - whichever comes first. | |
1738 | */ | |
1739 | static int | |
1740 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1741 | { | |
1742 | int depth = curr->lockdep_depth; | |
1743 | struct held_lock *hlock; | |
d6d897ce | 1744 | |
fbb9ce95 | 1745 | /* |
8e18257d PZ |
1746 | * Debugging checks. |
1747 | * | |
1748 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1749 | */ |
8e18257d PZ |
1750 | if (!depth) |
1751 | goto out_bug; | |
fbb9ce95 | 1752 | /* |
8e18257d PZ |
1753 | * At least two relevant locks must exist for this |
1754 | * to be a head: | |
fbb9ce95 | 1755 | */ |
8e18257d PZ |
1756 | if (curr->held_locks[depth].irq_context != |
1757 | curr->held_locks[depth-1].irq_context) | |
1758 | goto out_bug; | |
74c383f1 | 1759 | |
8e18257d PZ |
1760 | for (;;) { |
1761 | int distance = curr->lockdep_depth - depth + 1; | |
1762 | hlock = curr->held_locks + depth-1; | |
1763 | /* | |
1764 | * Only non-recursive-read entries get new dependencies | |
1765 | * added: | |
1766 | */ | |
1767 | if (hlock->read != 2) { | |
1768 | if (!check_prev_add(curr, hlock, next, distance)) | |
1769 | return 0; | |
1770 | /* | |
1771 | * Stop after the first non-trylock entry, | |
1772 | * as non-trylock entries have added their | |
1773 | * own direct dependencies already, so this | |
1774 | * lock is connected to them indirectly: | |
1775 | */ | |
1776 | if (!hlock->trylock) | |
1777 | break; | |
74c383f1 | 1778 | } |
8e18257d PZ |
1779 | depth--; |
1780 | /* | |
1781 | * End of lock-stack? | |
1782 | */ | |
1783 | if (!depth) | |
1784 | break; | |
1785 | /* | |
1786 | * Stop the search if we cross into another context: | |
1787 | */ | |
1788 | if (curr->held_locks[depth].irq_context != | |
1789 | curr->held_locks[depth-1].irq_context) | |
1790 | break; | |
fbb9ce95 | 1791 | } |
8e18257d PZ |
1792 | return 1; |
1793 | out_bug: | |
1794 | if (!debug_locks_off_graph_unlock()) | |
1795 | return 0; | |
fbb9ce95 | 1796 | |
8e18257d | 1797 | WARN_ON(1); |
fbb9ce95 | 1798 | |
8e18257d | 1799 | return 0; |
fbb9ce95 IM |
1800 | } |
1801 | ||
8e18257d | 1802 | unsigned long nr_lock_chains; |
443cd507 | 1803 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1804 | int nr_chain_hlocks; |
443cd507 HY |
1805 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1806 | ||
1807 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1808 | { | |
1809 | return lock_classes + chain_hlocks[chain->base + i]; | |
1810 | } | |
8e18257d | 1811 | |
fbb9ce95 IM |
1812 | /* |
1813 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1814 | * add it and return 1 - in this case the new dependency chain is |
1815 | * validated. If the key is already hashed, return 0. | |
1816 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1817 | */ |
443cd507 HY |
1818 | static inline int lookup_chain_cache(struct task_struct *curr, |
1819 | struct held_lock *hlock, | |
1820 | u64 chain_key) | |
fbb9ce95 | 1821 | { |
f82b217e | 1822 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1823 | struct list_head *hash_head = chainhashentry(chain_key); |
1824 | struct lock_chain *chain; | |
443cd507 | 1825 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1826 | int i, j, n, cn; |
fbb9ce95 | 1827 | |
381a2292 JP |
1828 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1829 | return 0; | |
fbb9ce95 IM |
1830 | /* |
1831 | * We can walk it lock-free, because entries only get added | |
1832 | * to the hash: | |
1833 | */ | |
1834 | list_for_each_entry(chain, hash_head, entry) { | |
1835 | if (chain->chain_key == chain_key) { | |
1836 | cache_hit: | |
1837 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1838 | if (very_verbose(class)) |
755cd900 AM |
1839 | printk("\nhash chain already cached, key: " |
1840 | "%016Lx tail class: [%p] %s\n", | |
1841 | (unsigned long long)chain_key, | |
1842 | class->key, class->name); | |
fbb9ce95 IM |
1843 | return 0; |
1844 | } | |
1845 | } | |
81fc685a | 1846 | if (very_verbose(class)) |
755cd900 AM |
1847 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1848 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1849 | /* |
1850 | * Allocate a new chain entry from the static array, and add | |
1851 | * it to the hash: | |
1852 | */ | |
74c383f1 IM |
1853 | if (!graph_lock()) |
1854 | return 0; | |
fbb9ce95 IM |
1855 | /* |
1856 | * We have to walk the chain again locked - to avoid duplicates: | |
1857 | */ | |
1858 | list_for_each_entry(chain, hash_head, entry) { | |
1859 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1860 | graph_unlock(); |
fbb9ce95 IM |
1861 | goto cache_hit; |
1862 | } | |
1863 | } | |
1864 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1865 | if (!debug_locks_off_graph_unlock()) |
1866 | return 0; | |
1867 | ||
fbb9ce95 IM |
1868 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1869 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 1870 | dump_stack(); |
fbb9ce95 IM |
1871 | return 0; |
1872 | } | |
1873 | chain = lock_chains + nr_lock_chains++; | |
1874 | chain->chain_key = chain_key; | |
443cd507 HY |
1875 | chain->irq_context = hlock->irq_context; |
1876 | /* Find the first held_lock of current chain */ | |
1877 | hlock_next = hlock; | |
1878 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1879 | hlock_curr = curr->held_locks + i; | |
1880 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1881 | break; | |
1882 | hlock_next = hlock; | |
1883 | } | |
1884 | i++; | |
1885 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1886 | cn = nr_chain_hlocks; |
1887 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1888 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1889 | if (n == cn) | |
1890 | break; | |
1891 | cn = n; | |
1892 | } | |
1893 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1894 | chain->base = cn; | |
443cd507 | 1895 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1896 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1897 | chain_hlocks[chain->base + j] = lock_id; |
1898 | } | |
1899 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1900 | } | |
fbb9ce95 IM |
1901 | list_add_tail_rcu(&chain->entry, hash_head); |
1902 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1903 | inc_chains(); |
1904 | ||
1905 | return 1; | |
1906 | } | |
1907 | ||
1908 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1909 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1910 | { |
1911 | /* | |
1912 | * Trylock needs to maintain the stack of held locks, but it | |
1913 | * does not add new dependencies, because trylock can be done | |
1914 | * in any order. | |
1915 | * | |
1916 | * We look up the chain_key and do the O(N^2) check and update of | |
1917 | * the dependencies only if this is a new dependency chain. | |
1918 | * (If lookup_chain_cache() returns with 1 it acquires | |
1919 | * graph_lock for us) | |
1920 | */ | |
1921 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1922 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1923 | /* |
1924 | * Check whether last held lock: | |
1925 | * | |
1926 | * - is irq-safe, if this lock is irq-unsafe | |
1927 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1928 | * | |
1929 | * And check whether the new lock's dependency graph | |
1930 | * could lead back to the previous lock. | |
1931 | * | |
1932 | * any of these scenarios could lead to a deadlock. If | |
1933 | * All validations | |
1934 | */ | |
1935 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1936 | ||
1937 | if (!ret) | |
1938 | return 0; | |
1939 | /* | |
1940 | * Mark recursive read, as we jump over it when | |
1941 | * building dependencies (just like we jump over | |
1942 | * trylock entries): | |
1943 | */ | |
1944 | if (ret == 2) | |
1945 | hlock->read = 2; | |
1946 | /* | |
1947 | * Add dependency only if this lock is not the head | |
1948 | * of the chain, and if it's not a secondary read-lock: | |
1949 | */ | |
1950 | if (!chain_head && ret != 2) | |
1951 | if (!check_prevs_add(curr, hlock)) | |
1952 | return 0; | |
1953 | graph_unlock(); | |
1954 | } else | |
1955 | /* after lookup_chain_cache(): */ | |
1956 | if (unlikely(!debug_locks)) | |
1957 | return 0; | |
fbb9ce95 IM |
1958 | |
1959 | return 1; | |
1960 | } | |
8e18257d PZ |
1961 | #else |
1962 | static inline int validate_chain(struct task_struct *curr, | |
1963 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1964 | int chain_head, u64 chain_key) |
8e18257d PZ |
1965 | { |
1966 | return 1; | |
1967 | } | |
ca58abcb | 1968 | #endif |
fbb9ce95 IM |
1969 | |
1970 | /* | |
1971 | * We are building curr_chain_key incrementally, so double-check | |
1972 | * it from scratch, to make sure that it's done correctly: | |
1973 | */ | |
1d09daa5 | 1974 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1975 | { |
1976 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1977 | struct held_lock *hlock, *prev_hlock = NULL; | |
1978 | unsigned int i, id; | |
1979 | u64 chain_key = 0; | |
1980 | ||
1981 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1982 | hlock = curr->held_locks + i; | |
1983 | if (chain_key != hlock->prev_chain_key) { | |
1984 | debug_locks_off(); | |
2df8b1d6 | 1985 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1986 | curr->lockdep_depth, i, |
1987 | (unsigned long long)chain_key, | |
1988 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1989 | return; |
1990 | } | |
f82b217e | 1991 | id = hlock->class_idx - 1; |
381a2292 JP |
1992 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1993 | return; | |
1994 | ||
fbb9ce95 IM |
1995 | if (prev_hlock && (prev_hlock->irq_context != |
1996 | hlock->irq_context)) | |
1997 | chain_key = 0; | |
1998 | chain_key = iterate_chain_key(chain_key, id); | |
1999 | prev_hlock = hlock; | |
2000 | } | |
2001 | if (chain_key != curr->curr_chain_key) { | |
2002 | debug_locks_off(); | |
2df8b1d6 | 2003 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2004 | curr->lockdep_depth, i, |
2005 | (unsigned long long)chain_key, | |
2006 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2007 | } |
2008 | #endif | |
2009 | } | |
2010 | ||
8e18257d PZ |
2011 | static int |
2012 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2013 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2014 | { | |
2015 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2016 | return 0; | |
2017 | ||
2018 | printk("\n=================================\n"); | |
2019 | printk( "[ INFO: inconsistent lock state ]\n"); | |
2020 | print_kernel_version(); | |
2021 | printk( "---------------------------------\n"); | |
2022 | ||
2023 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2024 | usage_str[prev_bit], usage_str[new_bit]); | |
2025 | ||
2026 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2027 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2028 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2029 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2030 | trace_hardirqs_enabled(curr), | |
2031 | trace_softirqs_enabled(curr)); | |
2032 | print_lock(this); | |
2033 | ||
2034 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2035 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2036 | |
2037 | print_irqtrace_events(curr); | |
2038 | printk("\nother info that might help us debug this:\n"); | |
2039 | lockdep_print_held_locks(curr); | |
2040 | ||
2041 | printk("\nstack backtrace:\n"); | |
2042 | dump_stack(); | |
2043 | ||
2044 | return 0; | |
2045 | } | |
2046 | ||
2047 | /* | |
2048 | * Print out an error if an invalid bit is set: | |
2049 | */ | |
2050 | static inline int | |
2051 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2052 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2053 | { | |
f82b217e | 2054 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2055 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2056 | return 1; | |
2057 | } | |
2058 | ||
2059 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2060 | enum lock_usage_bit new_bit); | |
2061 | ||
81d68a96 | 2062 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2063 | |
2064 | /* | |
2065 | * print irq inversion bug: | |
2066 | */ | |
2067 | static int | |
24208ca7 ML |
2068 | print_irq_inversion_bug(struct task_struct *curr, |
2069 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2070 | struct held_lock *this, int forwards, |
2071 | const char *irqclass) | |
2072 | { | |
74c383f1 | 2073 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2074 | return 0; |
2075 | ||
2076 | printk("\n=========================================================\n"); | |
2077 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2078 | print_kernel_version(); |
fbb9ce95 IM |
2079 | printk( "---------------------------------------------------------\n"); |
2080 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2081 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2082 | print_lock(this); |
2083 | if (forwards) | |
26575e28 | 2084 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2085 | else |
26575e28 | 2086 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2087 | print_lock_name(other->class); |
fbb9ce95 IM |
2088 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2089 | ||
2090 | printk("\nother info that might help us debug this:\n"); | |
2091 | lockdep_print_held_locks(curr); | |
2092 | ||
24208ca7 ML |
2093 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2094 | if (!save_trace(&root->trace)) | |
2095 | return 0; | |
2096 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2097 | |
2098 | printk("\nstack backtrace:\n"); | |
2099 | dump_stack(); | |
2100 | ||
2101 | return 0; | |
2102 | } | |
2103 | ||
2104 | /* | |
2105 | * Prove that in the forwards-direction subgraph starting at <this> | |
2106 | * there is no lock matching <mask>: | |
2107 | */ | |
2108 | static int | |
2109 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2110 | enum lock_usage_bit bit, const char *irqclass) | |
2111 | { | |
2112 | int ret; | |
d7aaba14 ML |
2113 | struct lock_list root; |
2114 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2115 | |
d7aaba14 ML |
2116 | root.parent = NULL; |
2117 | root.class = hlock_class(this); | |
2118 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2119 | if (ret < 0) |
2120 | return print_bfs_bug(ret); | |
2121 | if (ret == 1) | |
2122 | return ret; | |
fbb9ce95 | 2123 | |
24208ca7 | 2124 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2125 | this, 1, irqclass); |
fbb9ce95 IM |
2126 | } |
2127 | ||
2128 | /* | |
2129 | * Prove that in the backwards-direction subgraph starting at <this> | |
2130 | * there is no lock matching <mask>: | |
2131 | */ | |
2132 | static int | |
2133 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2134 | enum lock_usage_bit bit, const char *irqclass) | |
2135 | { | |
2136 | int ret; | |
d7aaba14 ML |
2137 | struct lock_list root; |
2138 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2139 | |
d7aaba14 ML |
2140 | root.parent = NULL; |
2141 | root.class = hlock_class(this); | |
2142 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2143 | if (ret < 0) |
2144 | return print_bfs_bug(ret); | |
2145 | if (ret == 1) | |
2146 | return ret; | |
fbb9ce95 | 2147 | |
24208ca7 | 2148 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2149 | this, 1, irqclass); |
fbb9ce95 IM |
2150 | } |
2151 | ||
3117df04 | 2152 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2153 | { |
2154 | printk("irq event stamp: %u\n", curr->irq_events); | |
2155 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2156 | print_ip_sym(curr->hardirq_enable_ip); | |
2157 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2158 | print_ip_sym(curr->hardirq_disable_ip); | |
2159 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2160 | print_ip_sym(curr->softirq_enable_ip); | |
2161 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2162 | print_ip_sym(curr->softirq_disable_ip); | |
2163 | } | |
2164 | ||
cd95302d | 2165 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2166 | { |
8e18257d PZ |
2167 | #if HARDIRQ_VERBOSE |
2168 | return class_filter(class); | |
2169 | #endif | |
fbb9ce95 IM |
2170 | return 0; |
2171 | } | |
2172 | ||
cd95302d | 2173 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2174 | { |
8e18257d PZ |
2175 | #if SOFTIRQ_VERBOSE |
2176 | return class_filter(class); | |
2177 | #endif | |
2178 | return 0; | |
fbb9ce95 IM |
2179 | } |
2180 | ||
cd95302d | 2181 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2182 | { |
2183 | #if RECLAIM_VERBOSE | |
2184 | return class_filter(class); | |
2185 | #endif | |
2186 | return 0; | |
2187 | } | |
2188 | ||
fbb9ce95 IM |
2189 | #define STRICT_READ_CHECKS 1 |
2190 | ||
cd95302d PZ |
2191 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2192 | #define LOCKDEP_STATE(__STATE) \ | |
2193 | __STATE##_verbose, | |
2194 | #include "lockdep_states.h" | |
2195 | #undef LOCKDEP_STATE | |
2196 | }; | |
2197 | ||
2198 | static inline int state_verbose(enum lock_usage_bit bit, | |
2199 | struct lock_class *class) | |
2200 | { | |
2201 | return state_verbose_f[bit >> 2](class); | |
2202 | } | |
2203 | ||
42c50d54 PZ |
2204 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2205 | enum lock_usage_bit bit, const char *name); | |
2206 | ||
6a6904d3 | 2207 | static int |
1c21f14e PZ |
2208 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2209 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2210 | { |
f989209e | 2211 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2212 | int read = new_bit & 1; |
42c50d54 PZ |
2213 | int dir = new_bit & 2; |
2214 | ||
38aa2714 PZ |
2215 | /* |
2216 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2217 | * has ENABLED state, which would allow recursion deadlocks. | |
2218 | * | |
2219 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2220 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2221 | */ | |
42c50d54 PZ |
2222 | check_usage_f usage = dir ? |
2223 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2224 | |
38aa2714 PZ |
2225 | /* |
2226 | * Validate that this particular lock does not have conflicting | |
2227 | * usage states. | |
2228 | */ | |
6a6904d3 PZ |
2229 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2230 | return 0; | |
42c50d54 | 2231 | |
38aa2714 PZ |
2232 | /* |
2233 | * Validate that the lock dependencies don't have conflicting usage | |
2234 | * states. | |
2235 | */ | |
2236 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2237 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2238 | return 0; |
780e820b | 2239 | |
38aa2714 PZ |
2240 | /* |
2241 | * Check for read in write conflicts | |
2242 | */ | |
2243 | if (!read) { | |
2244 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2245 | return 0; | |
2246 | ||
2247 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2248 | !usage(curr, this, excl_bit + 1, |
2249 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2250 | return 0; |
2251 | } | |
780e820b | 2252 | |
cd95302d | 2253 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2254 | return 2; |
2255 | ||
2256 | return 1; | |
2257 | } | |
2258 | ||
cf40bd16 | 2259 | enum mark_type { |
36bfb9bb PZ |
2260 | #define LOCKDEP_STATE(__STATE) __STATE, |
2261 | #include "lockdep_states.h" | |
2262 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2263 | }; |
2264 | ||
fbb9ce95 IM |
2265 | /* |
2266 | * Mark all held locks with a usage bit: | |
2267 | */ | |
1d09daa5 | 2268 | static int |
cf40bd16 | 2269 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2270 | { |
2271 | enum lock_usage_bit usage_bit; | |
2272 | struct held_lock *hlock; | |
2273 | int i; | |
2274 | ||
2275 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2276 | hlock = curr->held_locks + i; | |
2277 | ||
cf2ad4d1 PZ |
2278 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2279 | if (hlock->read) | |
2280 | usage_bit += 1; /* READ */ | |
2281 | ||
2282 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2283 | |
4ff773bb | 2284 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2285 | return 0; |
2286 | } | |
2287 | ||
2288 | return 1; | |
2289 | } | |
2290 | ||
2291 | /* | |
2292 | * Debugging helper: via this flag we know that we are in | |
2293 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2294 | */ | |
2295 | static int early_boot_irqs_enabled; | |
2296 | ||
2297 | void early_boot_irqs_off(void) | |
2298 | { | |
2299 | early_boot_irqs_enabled = 0; | |
2300 | } | |
2301 | ||
2302 | void early_boot_irqs_on(void) | |
2303 | { | |
2304 | early_boot_irqs_enabled = 1; | |
2305 | } | |
2306 | ||
2307 | /* | |
2308 | * Hardirqs will be enabled: | |
2309 | */ | |
6afe40b4 | 2310 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2311 | { |
2312 | struct task_struct *curr = current; | |
fbb9ce95 | 2313 | |
6afe40b4 | 2314 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2315 | |
fbb9ce95 IM |
2316 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2317 | return; | |
2318 | ||
2319 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2320 | return; | |
2321 | ||
2322 | if (unlikely(curr->hardirqs_enabled)) { | |
2323 | debug_atomic_inc(&redundant_hardirqs_on); | |
2324 | return; | |
2325 | } | |
2326 | /* we'll do an OFF -> ON transition: */ | |
2327 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2328 | |
2329 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2330 | return; | |
2331 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2332 | return; | |
2333 | /* | |
2334 | * We are going to turn hardirqs on, so set the | |
2335 | * usage bit for all held locks: | |
2336 | */ | |
cf40bd16 | 2337 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2338 | return; |
2339 | /* | |
2340 | * If we have softirqs enabled, then set the usage | |
2341 | * bit for all held locks. (disabled hardirqs prevented | |
2342 | * this bit from being set before) | |
2343 | */ | |
2344 | if (curr->softirqs_enabled) | |
cf40bd16 | 2345 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2346 | return; |
2347 | ||
8e18257d PZ |
2348 | curr->hardirq_enable_ip = ip; |
2349 | curr->hardirq_enable_event = ++curr->irq_events; | |
2350 | debug_atomic_inc(&hardirqs_on_events); | |
2351 | } | |
81d68a96 | 2352 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2353 | |
1d09daa5 | 2354 | void trace_hardirqs_on(void) |
81d68a96 SR |
2355 | { |
2356 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2357 | } | |
8e18257d PZ |
2358 | EXPORT_SYMBOL(trace_hardirqs_on); |
2359 | ||
2360 | /* | |
2361 | * Hardirqs were disabled: | |
2362 | */ | |
6afe40b4 | 2363 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2364 | { |
2365 | struct task_struct *curr = current; | |
2366 | ||
6afe40b4 | 2367 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2368 | |
8e18257d PZ |
2369 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2370 | return; | |
2371 | ||
2372 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2373 | return; | |
2374 | ||
2375 | if (curr->hardirqs_enabled) { | |
2376 | /* | |
2377 | * We have done an ON -> OFF transition: | |
2378 | */ | |
2379 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2380 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2381 | curr->hardirq_disable_event = ++curr->irq_events; |
2382 | debug_atomic_inc(&hardirqs_off_events); | |
2383 | } else | |
2384 | debug_atomic_inc(&redundant_hardirqs_off); | |
2385 | } | |
81d68a96 | 2386 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2387 | |
1d09daa5 | 2388 | void trace_hardirqs_off(void) |
81d68a96 SR |
2389 | { |
2390 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2391 | } | |
8e18257d PZ |
2392 | EXPORT_SYMBOL(trace_hardirqs_off); |
2393 | ||
2394 | /* | |
2395 | * Softirqs will be enabled: | |
2396 | */ | |
2397 | void trace_softirqs_on(unsigned long ip) | |
2398 | { | |
2399 | struct task_struct *curr = current; | |
2400 | ||
2401 | if (unlikely(!debug_locks)) | |
2402 | return; | |
2403 | ||
2404 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2405 | return; | |
2406 | ||
2407 | if (curr->softirqs_enabled) { | |
2408 | debug_atomic_inc(&redundant_softirqs_on); | |
2409 | return; | |
2410 | } | |
2411 | ||
2412 | /* | |
2413 | * We'll do an OFF -> ON transition: | |
2414 | */ | |
2415 | curr->softirqs_enabled = 1; | |
2416 | curr->softirq_enable_ip = ip; | |
2417 | curr->softirq_enable_event = ++curr->irq_events; | |
2418 | debug_atomic_inc(&softirqs_on_events); | |
2419 | /* | |
2420 | * We are going to turn softirqs on, so set the | |
2421 | * usage bit for all held locks, if hardirqs are | |
2422 | * enabled too: | |
2423 | */ | |
2424 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2425 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2426 | } |
2427 | ||
2428 | /* | |
2429 | * Softirqs were disabled: | |
2430 | */ | |
2431 | void trace_softirqs_off(unsigned long ip) | |
2432 | { | |
2433 | struct task_struct *curr = current; | |
2434 | ||
2435 | if (unlikely(!debug_locks)) | |
2436 | return; | |
2437 | ||
2438 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2439 | return; | |
2440 | ||
2441 | if (curr->softirqs_enabled) { | |
2442 | /* | |
2443 | * We have done an ON -> OFF transition: | |
2444 | */ | |
2445 | curr->softirqs_enabled = 0; | |
2446 | curr->softirq_disable_ip = ip; | |
2447 | curr->softirq_disable_event = ++curr->irq_events; | |
2448 | debug_atomic_inc(&softirqs_off_events); | |
2449 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2450 | } else | |
2451 | debug_atomic_inc(&redundant_softirqs_off); | |
2452 | } | |
2453 | ||
2f850181 | 2454 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2455 | { |
2456 | struct task_struct *curr = current; | |
2457 | ||
2458 | if (unlikely(!debug_locks)) | |
2459 | return; | |
2460 | ||
2461 | /* no reclaim without waiting on it */ | |
2462 | if (!(gfp_mask & __GFP_WAIT)) | |
2463 | return; | |
2464 | ||
2465 | /* this guy won't enter reclaim */ | |
2466 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2467 | return; | |
2468 | ||
2469 | /* We're only interested __GFP_FS allocations for now */ | |
2470 | if (!(gfp_mask & __GFP_FS)) | |
2471 | return; | |
2472 | ||
2f850181 | 2473 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2474 | return; |
2475 | ||
2476 | mark_held_locks(curr, RECLAIM_FS); | |
2477 | } | |
2478 | ||
2f850181 PZ |
2479 | static void check_flags(unsigned long flags); |
2480 | ||
2481 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2482 | { | |
2483 | unsigned long flags; | |
2484 | ||
2485 | if (unlikely(current->lockdep_recursion)) | |
2486 | return; | |
2487 | ||
2488 | raw_local_irq_save(flags); | |
2489 | check_flags(flags); | |
2490 | current->lockdep_recursion = 1; | |
2491 | __lockdep_trace_alloc(gfp_mask, flags); | |
2492 | current->lockdep_recursion = 0; | |
2493 | raw_local_irq_restore(flags); | |
2494 | } | |
2495 | ||
8e18257d PZ |
2496 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2497 | { | |
2498 | /* | |
2499 | * If non-trylock use in a hardirq or softirq context, then | |
2500 | * mark the lock as used in these contexts: | |
2501 | */ | |
2502 | if (!hlock->trylock) { | |
2503 | if (hlock->read) { | |
2504 | if (curr->hardirq_context) | |
2505 | if (!mark_lock(curr, hlock, | |
2506 | LOCK_USED_IN_HARDIRQ_READ)) | |
2507 | return 0; | |
2508 | if (curr->softirq_context) | |
2509 | if (!mark_lock(curr, hlock, | |
2510 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2511 | return 0; | |
2512 | } else { | |
2513 | if (curr->hardirq_context) | |
2514 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2515 | return 0; | |
2516 | if (curr->softirq_context) | |
2517 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2518 | return 0; | |
2519 | } | |
2520 | } | |
2521 | if (!hlock->hardirqs_off) { | |
2522 | if (hlock->read) { | |
2523 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2524 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2525 | return 0; |
2526 | if (curr->softirqs_enabled) | |
2527 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2528 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2529 | return 0; |
2530 | } else { | |
2531 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2532 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2533 | return 0; |
2534 | if (curr->softirqs_enabled) | |
2535 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2536 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2537 | return 0; |
2538 | } | |
2539 | } | |
2540 | ||
cf40bd16 NP |
2541 | /* |
2542 | * We reuse the irq context infrastructure more broadly as a general | |
2543 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2544 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2545 | * allocation). | |
2546 | */ | |
2547 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2548 | if (hlock->read) { | |
2549 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2550 | return 0; | |
2551 | } else { | |
2552 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2553 | return 0; | |
2554 | } | |
2555 | } | |
2556 | ||
8e18257d PZ |
2557 | return 1; |
2558 | } | |
2559 | ||
2560 | static int separate_irq_context(struct task_struct *curr, | |
2561 | struct held_lock *hlock) | |
2562 | { | |
2563 | unsigned int depth = curr->lockdep_depth; | |
2564 | ||
2565 | /* | |
2566 | * Keep track of points where we cross into an interrupt context: | |
2567 | */ | |
2568 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2569 | curr->softirq_context; | |
2570 | if (depth) { | |
2571 | struct held_lock *prev_hlock; | |
2572 | ||
2573 | prev_hlock = curr->held_locks + depth-1; | |
2574 | /* | |
2575 | * If we cross into another context, reset the | |
2576 | * hash key (this also prevents the checking and the | |
2577 | * adding of the dependency to 'prev'): | |
2578 | */ | |
2579 | if (prev_hlock->irq_context != hlock->irq_context) | |
2580 | return 1; | |
2581 | } | |
2582 | return 0; | |
fbb9ce95 IM |
2583 | } |
2584 | ||
8e18257d | 2585 | #else |
fbb9ce95 | 2586 | |
8e18257d PZ |
2587 | static inline |
2588 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2589 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2590 | { |
8e18257d PZ |
2591 | WARN_ON(1); |
2592 | return 1; | |
2593 | } | |
fbb9ce95 | 2594 | |
8e18257d PZ |
2595 | static inline int mark_irqflags(struct task_struct *curr, |
2596 | struct held_lock *hlock) | |
2597 | { | |
2598 | return 1; | |
2599 | } | |
fbb9ce95 | 2600 | |
8e18257d PZ |
2601 | static inline int separate_irq_context(struct task_struct *curr, |
2602 | struct held_lock *hlock) | |
2603 | { | |
2604 | return 0; | |
fbb9ce95 IM |
2605 | } |
2606 | ||
868a23a8 PZ |
2607 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2608 | { | |
2609 | } | |
2610 | ||
8e18257d | 2611 | #endif |
fbb9ce95 IM |
2612 | |
2613 | /* | |
8e18257d | 2614 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2615 | */ |
1d09daa5 | 2616 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2617 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2618 | { |
8e18257d | 2619 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2620 | |
2621 | /* | |
8e18257d PZ |
2622 | * If already set then do not dirty the cacheline, |
2623 | * nor do any checks: | |
fbb9ce95 | 2624 | */ |
f82b217e | 2625 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2626 | return 1; |
2627 | ||
2628 | if (!graph_lock()) | |
2629 | return 0; | |
fbb9ce95 | 2630 | /* |
8e18257d | 2631 | * Make sure we didnt race: |
fbb9ce95 | 2632 | */ |
f82b217e | 2633 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2634 | graph_unlock(); |
2635 | return 1; | |
2636 | } | |
fbb9ce95 | 2637 | |
f82b217e | 2638 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2639 | |
f82b217e | 2640 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2641 | return 0; |
fbb9ce95 | 2642 | |
8e18257d | 2643 | switch (new_bit) { |
5346417e PZ |
2644 | #define LOCKDEP_STATE(__STATE) \ |
2645 | case LOCK_USED_IN_##__STATE: \ | |
2646 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2647 | case LOCK_ENABLED_##__STATE: \ | |
2648 | case LOCK_ENABLED_##__STATE##_READ: | |
2649 | #include "lockdep_states.h" | |
2650 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2651 | ret = mark_lock_irq(curr, this, new_bit); |
2652 | if (!ret) | |
2653 | return 0; | |
2654 | break; | |
2655 | case LOCK_USED: | |
8e18257d PZ |
2656 | debug_atomic_dec(&nr_unused_locks); |
2657 | break; | |
2658 | default: | |
2659 | if (!debug_locks_off_graph_unlock()) | |
2660 | return 0; | |
2661 | WARN_ON(1); | |
2662 | return 0; | |
2663 | } | |
fbb9ce95 | 2664 | |
8e18257d PZ |
2665 | graph_unlock(); |
2666 | ||
2667 | /* | |
2668 | * We must printk outside of the graph_lock: | |
2669 | */ | |
2670 | if (ret == 2) { | |
2671 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2672 | print_lock(this); | |
2673 | print_irqtrace_events(curr); | |
2674 | dump_stack(); | |
2675 | } | |
2676 | ||
2677 | return ret; | |
2678 | } | |
fbb9ce95 IM |
2679 | |
2680 | /* | |
2681 | * Initialize a lock instance's lock-class mapping info: | |
2682 | */ | |
2683 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2684 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2685 | { |
c8a25005 PZ |
2686 | lock->class_cache = NULL; |
2687 | #ifdef CONFIG_LOCK_STAT | |
2688 | lock->cpu = raw_smp_processor_id(); | |
2689 | #endif | |
2690 | ||
2691 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2692 | lock->name = "NULL"; | |
fbb9ce95 | 2693 | return; |
c8a25005 PZ |
2694 | } |
2695 | ||
2696 | lock->name = name; | |
fbb9ce95 IM |
2697 | |
2698 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2699 | return; | |
fbb9ce95 IM |
2700 | /* |
2701 | * Sanity check, the lock-class key must be persistent: | |
2702 | */ | |
2703 | if (!static_obj(key)) { | |
2704 | printk("BUG: key %p not in .data!\n", key); | |
2705 | DEBUG_LOCKS_WARN_ON(1); | |
2706 | return; | |
2707 | } | |
fbb9ce95 | 2708 | lock->key = key; |
c8a25005 PZ |
2709 | |
2710 | if (unlikely(!debug_locks)) | |
2711 | return; | |
2712 | ||
4dfbb9d8 PZ |
2713 | if (subclass) |
2714 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2715 | } |
fbb9ce95 IM |
2716 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2717 | ||
2718 | /* | |
2719 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2720 | * We maintain the dependency maps and validate the locking attempt: | |
2721 | */ | |
2722 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2723 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
2724 | struct lockdep_map *nest_lock, unsigned long ip, |
2725 | int references) | |
fbb9ce95 IM |
2726 | { |
2727 | struct task_struct *curr = current; | |
d6d897ce | 2728 | struct lock_class *class = NULL; |
fbb9ce95 | 2729 | struct held_lock *hlock; |
fbb9ce95 IM |
2730 | unsigned int depth, id; |
2731 | int chain_head = 0; | |
bb97a91e | 2732 | int class_idx; |
fbb9ce95 IM |
2733 | u64 chain_key; |
2734 | ||
f20786ff PZ |
2735 | if (!prove_locking) |
2736 | check = 1; | |
2737 | ||
fbb9ce95 IM |
2738 | if (unlikely(!debug_locks)) |
2739 | return 0; | |
2740 | ||
2741 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2742 | return 0; | |
2743 | ||
2744 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2745 | debug_locks_off(); | |
2746 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2747 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2748 | dump_stack(); |
fbb9ce95 IM |
2749 | return 0; |
2750 | } | |
2751 | ||
d6d897ce IM |
2752 | if (!subclass) |
2753 | class = lock->class_cache; | |
2754 | /* | |
2755 | * Not cached yet or subclass? | |
2756 | */ | |
fbb9ce95 | 2757 | if (unlikely(!class)) { |
4dfbb9d8 | 2758 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2759 | if (!class) |
2760 | return 0; | |
2761 | } | |
2762 | debug_atomic_inc((atomic_t *)&class->ops); | |
2763 | if (very_verbose(class)) { | |
2764 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2765 | if (class->name_version > 1) | |
2766 | printk("#%d", class->name_version); | |
2767 | printk("\n"); | |
2768 | dump_stack(); | |
2769 | } | |
2770 | ||
2771 | /* | |
2772 | * Add the lock to the list of currently held locks. | |
2773 | * (we dont increase the depth just yet, up until the | |
2774 | * dependency checks are done) | |
2775 | */ | |
2776 | depth = curr->lockdep_depth; | |
2777 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2778 | return 0; | |
2779 | ||
bb97a91e PZ |
2780 | class_idx = class - lock_classes + 1; |
2781 | ||
2782 | if (depth) { | |
2783 | hlock = curr->held_locks + depth - 1; | |
2784 | if (hlock->class_idx == class_idx && nest_lock) { | |
2785 | if (hlock->references) | |
2786 | hlock->references++; | |
2787 | else | |
2788 | hlock->references = 2; | |
2789 | ||
2790 | return 1; | |
2791 | } | |
2792 | } | |
2793 | ||
fbb9ce95 | 2794 | hlock = curr->held_locks + depth; |
f82b217e DJ |
2795 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2796 | return 0; | |
bb97a91e | 2797 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
2798 | hlock->acquire_ip = ip; |
2799 | hlock->instance = lock; | |
7531e2f3 | 2800 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2801 | hlock->trylock = trylock; |
2802 | hlock->read = read; | |
2803 | hlock->check = check; | |
6951b12a | 2804 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 2805 | hlock->references = references; |
f20786ff PZ |
2806 | #ifdef CONFIG_LOCK_STAT |
2807 | hlock->waittime_stamp = 0; | |
3365e779 | 2808 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 2809 | #endif |
fbb9ce95 | 2810 | |
8e18257d PZ |
2811 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2812 | return 0; | |
2813 | ||
fbb9ce95 | 2814 | /* mark it as used: */ |
4ff773bb | 2815 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2816 | return 0; |
8e18257d | 2817 | |
fbb9ce95 | 2818 | /* |
17aacfb9 | 2819 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2820 | * lock keys along the dependency chain. We save the hash value |
2821 | * at every step so that we can get the current hash easily | |
2822 | * after unlock. The chain hash is then used to cache dependency | |
2823 | * results. | |
2824 | * | |
2825 | * The 'key ID' is what is the most compact key value to drive | |
2826 | * the hash, not class->key. | |
2827 | */ | |
2828 | id = class - lock_classes; | |
2829 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2830 | return 0; | |
2831 | ||
2832 | chain_key = curr->curr_chain_key; | |
2833 | if (!depth) { | |
2834 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2835 | return 0; | |
2836 | chain_head = 1; | |
2837 | } | |
2838 | ||
2839 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2840 | if (separate_irq_context(curr, hlock)) { |
2841 | chain_key = 0; | |
2842 | chain_head = 1; | |
fbb9ce95 | 2843 | } |
fbb9ce95 | 2844 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2845 | |
3aa416b0 | 2846 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2847 | return 0; |
381a2292 | 2848 | |
3aa416b0 | 2849 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2850 | curr->lockdep_depth++; |
2851 | check_chain_key(curr); | |
60e114d1 JP |
2852 | #ifdef CONFIG_DEBUG_LOCKDEP |
2853 | if (unlikely(!debug_locks)) | |
2854 | return 0; | |
2855 | #endif | |
fbb9ce95 IM |
2856 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2857 | debug_locks_off(); | |
2858 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2859 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2860 | dump_stack(); |
fbb9ce95 IM |
2861 | return 0; |
2862 | } | |
381a2292 | 2863 | |
fbb9ce95 IM |
2864 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2865 | max_lockdep_depth = curr->lockdep_depth; | |
2866 | ||
2867 | return 1; | |
2868 | } | |
2869 | ||
2870 | static int | |
2871 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2872 | unsigned long ip) | |
2873 | { | |
2874 | if (!debug_locks_off()) | |
2875 | return 0; | |
2876 | if (debug_locks_silent) | |
2877 | return 0; | |
2878 | ||
2879 | printk("\n=====================================\n"); | |
2880 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2881 | printk( "-------------------------------------\n"); | |
2882 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2883 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2884 | print_lockdep_cache(lock); |
2885 | printk(") at:\n"); | |
2886 | print_ip_sym(ip); | |
2887 | printk("but there are no more locks to release!\n"); | |
2888 | printk("\nother info that might help us debug this:\n"); | |
2889 | lockdep_print_held_locks(curr); | |
2890 | ||
2891 | printk("\nstack backtrace:\n"); | |
2892 | dump_stack(); | |
2893 | ||
2894 | return 0; | |
2895 | } | |
2896 | ||
2897 | /* | |
2898 | * Common debugging checks for both nested and non-nested unlock: | |
2899 | */ | |
2900 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2901 | unsigned long ip) | |
2902 | { | |
2903 | if (unlikely(!debug_locks)) | |
2904 | return 0; | |
2905 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2906 | return 0; | |
2907 | ||
2908 | if (curr->lockdep_depth <= 0) | |
2909 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2910 | ||
2911 | return 1; | |
2912 | } | |
2913 | ||
bb97a91e PZ |
2914 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
2915 | { | |
2916 | if (hlock->instance == lock) | |
2917 | return 1; | |
2918 | ||
2919 | if (hlock->references) { | |
2920 | struct lock_class *class = lock->class_cache; | |
2921 | ||
2922 | if (!class) | |
2923 | class = look_up_lock_class(lock, 0); | |
2924 | ||
2925 | if (DEBUG_LOCKS_WARN_ON(!class)) | |
2926 | return 0; | |
2927 | ||
2928 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) | |
2929 | return 0; | |
2930 | ||
2931 | if (hlock->class_idx == class - lock_classes + 1) | |
2932 | return 1; | |
2933 | } | |
2934 | ||
2935 | return 0; | |
2936 | } | |
2937 | ||
64aa348e | 2938 | static int |
00ef9f73 PZ |
2939 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2940 | struct lock_class_key *key, unsigned int subclass, | |
2941 | unsigned long ip) | |
64aa348e PZ |
2942 | { |
2943 | struct task_struct *curr = current; | |
2944 | struct held_lock *hlock, *prev_hlock; | |
2945 | struct lock_class *class; | |
2946 | unsigned int depth; | |
2947 | int i; | |
2948 | ||
2949 | depth = curr->lockdep_depth; | |
2950 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2951 | return 0; | |
2952 | ||
2953 | prev_hlock = NULL; | |
2954 | for (i = depth-1; i >= 0; i--) { | |
2955 | hlock = curr->held_locks + i; | |
2956 | /* | |
2957 | * We must not cross into another context: | |
2958 | */ | |
2959 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2960 | break; | |
bb97a91e | 2961 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
2962 | goto found_it; |
2963 | prev_hlock = hlock; | |
2964 | } | |
2965 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2966 | ||
2967 | found_it: | |
00ef9f73 | 2968 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2969 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2970 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2971 | |
2972 | curr->lockdep_depth = i; | |
2973 | curr->curr_chain_key = hlock->prev_chain_key; | |
2974 | ||
2975 | for (; i < depth; i++) { | |
2976 | hlock = curr->held_locks + i; | |
2977 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2978 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2979 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
2980 | hlock->nest_lock, hlock->acquire_ip, |
2981 | hlock->references)) | |
64aa348e PZ |
2982 | return 0; |
2983 | } | |
2984 | ||
2985 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2986 | return 0; | |
2987 | return 1; | |
2988 | } | |
2989 | ||
fbb9ce95 IM |
2990 | /* |
2991 | * Remove the lock to the list of currently held locks in a | |
2992 | * potentially non-nested (out of order) manner. This is a | |
2993 | * relatively rare operation, as all the unlock APIs default | |
2994 | * to nested mode (which uses lock_release()): | |
2995 | */ | |
2996 | static int | |
2997 | lock_release_non_nested(struct task_struct *curr, | |
2998 | struct lockdep_map *lock, unsigned long ip) | |
2999 | { | |
3000 | struct held_lock *hlock, *prev_hlock; | |
3001 | unsigned int depth; | |
3002 | int i; | |
3003 | ||
3004 | /* | |
3005 | * Check whether the lock exists in the current stack | |
3006 | * of held locks: | |
3007 | */ | |
3008 | depth = curr->lockdep_depth; | |
3009 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3010 | return 0; | |
3011 | ||
3012 | prev_hlock = NULL; | |
3013 | for (i = depth-1; i >= 0; i--) { | |
3014 | hlock = curr->held_locks + i; | |
3015 | /* | |
3016 | * We must not cross into another context: | |
3017 | */ | |
3018 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3019 | break; | |
bb97a91e | 3020 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3021 | goto found_it; |
3022 | prev_hlock = hlock; | |
3023 | } | |
3024 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3025 | ||
3026 | found_it: | |
bb97a91e PZ |
3027 | if (hlock->instance == lock) |
3028 | lock_release_holdtime(hlock); | |
3029 | ||
3030 | if (hlock->references) { | |
3031 | hlock->references--; | |
3032 | if (hlock->references) { | |
3033 | /* | |
3034 | * We had, and after removing one, still have | |
3035 | * references, the current lock stack is still | |
3036 | * valid. We're done! | |
3037 | */ | |
3038 | return 1; | |
3039 | } | |
3040 | } | |
f20786ff | 3041 | |
fbb9ce95 IM |
3042 | /* |
3043 | * We have the right lock to unlock, 'hlock' points to it. | |
3044 | * Now we remove it from the stack, and add back the other | |
3045 | * entries (if any), recalculating the hash along the way: | |
3046 | */ | |
bb97a91e | 3047 | |
fbb9ce95 IM |
3048 | curr->lockdep_depth = i; |
3049 | curr->curr_chain_key = hlock->prev_chain_key; | |
3050 | ||
3051 | for (i++; i < depth; i++) { | |
3052 | hlock = curr->held_locks + i; | |
3053 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3054 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3055 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3056 | hlock->nest_lock, hlock->acquire_ip, |
3057 | hlock->references)) | |
fbb9ce95 IM |
3058 | return 0; |
3059 | } | |
3060 | ||
3061 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
3062 | return 0; | |
3063 | return 1; | |
3064 | } | |
3065 | ||
3066 | /* | |
3067 | * Remove the lock to the list of currently held locks - this gets | |
3068 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3069 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3070 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3071 | */ | |
3072 | static int lock_release_nested(struct task_struct *curr, | |
3073 | struct lockdep_map *lock, unsigned long ip) | |
3074 | { | |
3075 | struct held_lock *hlock; | |
3076 | unsigned int depth; | |
3077 | ||
3078 | /* | |
3079 | * Pop off the top of the lock stack: | |
3080 | */ | |
3081 | depth = curr->lockdep_depth - 1; | |
3082 | hlock = curr->held_locks + depth; | |
3083 | ||
3084 | /* | |
3085 | * Is the unlock non-nested: | |
3086 | */ | |
bb97a91e | 3087 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3088 | return lock_release_non_nested(curr, lock, ip); |
3089 | curr->lockdep_depth--; | |
3090 | ||
3091 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
3092 | return 0; | |
3093 | ||
3094 | curr->curr_chain_key = hlock->prev_chain_key; | |
3095 | ||
f20786ff PZ |
3096 | lock_release_holdtime(hlock); |
3097 | ||
fbb9ce95 IM |
3098 | #ifdef CONFIG_DEBUG_LOCKDEP |
3099 | hlock->prev_chain_key = 0; | |
f82b217e | 3100 | hlock->class_idx = 0; |
fbb9ce95 IM |
3101 | hlock->acquire_ip = 0; |
3102 | hlock->irq_context = 0; | |
3103 | #endif | |
3104 | return 1; | |
3105 | } | |
3106 | ||
3107 | /* | |
3108 | * Remove the lock to the list of currently held locks - this gets | |
3109 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3110 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3111 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3112 | */ | |
3113 | static void | |
3114 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3115 | { | |
3116 | struct task_struct *curr = current; | |
3117 | ||
3118 | if (!check_unlock(curr, lock, ip)) | |
3119 | return; | |
3120 | ||
3121 | if (nested) { | |
3122 | if (!lock_release_nested(curr, lock, ip)) | |
3123 | return; | |
3124 | } else { | |
3125 | if (!lock_release_non_nested(curr, lock, ip)) | |
3126 | return; | |
3127 | } | |
3128 | ||
3129 | check_chain_key(curr); | |
3130 | } | |
3131 | ||
f607c668 PZ |
3132 | static int __lock_is_held(struct lockdep_map *lock) |
3133 | { | |
3134 | struct task_struct *curr = current; | |
3135 | int i; | |
3136 | ||
3137 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3138 | struct held_lock *hlock = curr->held_locks + i; |
3139 | ||
3140 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3141 | return 1; |
3142 | } | |
3143 | ||
3144 | return 0; | |
3145 | } | |
3146 | ||
fbb9ce95 IM |
3147 | /* |
3148 | * Check whether we follow the irq-flags state precisely: | |
3149 | */ | |
1d09daa5 | 3150 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3151 | { |
992860e9 IM |
3152 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3153 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3154 | if (!debug_locks) |
3155 | return; | |
3156 | ||
5f9fa8a6 IM |
3157 | if (irqs_disabled_flags(flags)) { |
3158 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3159 | printk("possible reason: unannotated irqs-off.\n"); | |
3160 | } | |
3161 | } else { | |
3162 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3163 | printk("possible reason: unannotated irqs-on.\n"); | |
3164 | } | |
3165 | } | |
fbb9ce95 IM |
3166 | |
3167 | /* | |
3168 | * We dont accurately track softirq state in e.g. | |
3169 | * hardirq contexts (such as on 4KSTACKS), so only | |
3170 | * check if not in hardirq contexts: | |
3171 | */ | |
3172 | if (!hardirq_count()) { | |
3173 | if (softirq_count()) | |
3174 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3175 | else | |
3176 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3177 | } | |
3178 | ||
3179 | if (!debug_locks) | |
3180 | print_irqtrace_events(current); | |
3181 | #endif | |
3182 | } | |
3183 | ||
00ef9f73 PZ |
3184 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3185 | struct lock_class_key *key, unsigned int subclass, | |
3186 | unsigned long ip) | |
64aa348e PZ |
3187 | { |
3188 | unsigned long flags; | |
3189 | ||
3190 | if (unlikely(current->lockdep_recursion)) | |
3191 | return; | |
3192 | ||
3193 | raw_local_irq_save(flags); | |
3194 | current->lockdep_recursion = 1; | |
3195 | check_flags(flags); | |
00ef9f73 | 3196 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3197 | check_chain_key(current); |
3198 | current->lockdep_recursion = 0; | |
3199 | raw_local_irq_restore(flags); | |
3200 | } | |
00ef9f73 | 3201 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3202 | |
fbb9ce95 IM |
3203 | /* |
3204 | * We are not always called with irqs disabled - do that here, | |
3205 | * and also avoid lockdep recursion: | |
3206 | */ | |
1d09daa5 | 3207 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3208 | int trylock, int read, int check, |
3209 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3210 | { |
3211 | unsigned long flags; | |
3212 | ||
efed792d PZ |
3213 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
3214 | ||
fbb9ce95 IM |
3215 | if (unlikely(current->lockdep_recursion)) |
3216 | return; | |
3217 | ||
3218 | raw_local_irq_save(flags); | |
3219 | check_flags(flags); | |
3220 | ||
3221 | current->lockdep_recursion = 1; | |
3222 | __lock_acquire(lock, subclass, trylock, read, check, | |
bb97a91e | 3223 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3224 | current->lockdep_recursion = 0; |
3225 | raw_local_irq_restore(flags); | |
3226 | } | |
fbb9ce95 IM |
3227 | EXPORT_SYMBOL_GPL(lock_acquire); |
3228 | ||
1d09daa5 | 3229 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3230 | unsigned long ip) |
fbb9ce95 IM |
3231 | { |
3232 | unsigned long flags; | |
3233 | ||
efed792d PZ |
3234 | trace_lock_release(lock, nested, ip); |
3235 | ||
fbb9ce95 IM |
3236 | if (unlikely(current->lockdep_recursion)) |
3237 | return; | |
3238 | ||
3239 | raw_local_irq_save(flags); | |
3240 | check_flags(flags); | |
3241 | current->lockdep_recursion = 1; | |
3242 | __lock_release(lock, nested, ip); | |
3243 | current->lockdep_recursion = 0; | |
3244 | raw_local_irq_restore(flags); | |
3245 | } | |
fbb9ce95 IM |
3246 | EXPORT_SYMBOL_GPL(lock_release); |
3247 | ||
f607c668 PZ |
3248 | int lock_is_held(struct lockdep_map *lock) |
3249 | { | |
3250 | unsigned long flags; | |
3251 | int ret = 0; | |
3252 | ||
3253 | if (unlikely(current->lockdep_recursion)) | |
3254 | return ret; | |
3255 | ||
3256 | raw_local_irq_save(flags); | |
3257 | check_flags(flags); | |
3258 | ||
3259 | current->lockdep_recursion = 1; | |
3260 | ret = __lock_is_held(lock); | |
3261 | current->lockdep_recursion = 0; | |
3262 | raw_local_irq_restore(flags); | |
3263 | ||
3264 | return ret; | |
3265 | } | |
3266 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3267 | ||
cf40bd16 NP |
3268 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3269 | { | |
3270 | current->lockdep_reclaim_gfp = gfp_mask; | |
3271 | } | |
3272 | ||
3273 | void lockdep_clear_current_reclaim_state(void) | |
3274 | { | |
3275 | current->lockdep_reclaim_gfp = 0; | |
3276 | } | |
3277 | ||
f20786ff PZ |
3278 | #ifdef CONFIG_LOCK_STAT |
3279 | static int | |
3280 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3281 | unsigned long ip) | |
3282 | { | |
3283 | if (!debug_locks_off()) | |
3284 | return 0; | |
3285 | if (debug_locks_silent) | |
3286 | return 0; | |
3287 | ||
3288 | printk("\n=================================\n"); | |
3289 | printk( "[ BUG: bad contention detected! ]\n"); | |
3290 | printk( "---------------------------------\n"); | |
3291 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3292 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3293 | print_lockdep_cache(lock); |
3294 | printk(") at:\n"); | |
3295 | print_ip_sym(ip); | |
3296 | printk("but there are no locks held!\n"); | |
3297 | printk("\nother info that might help us debug this:\n"); | |
3298 | lockdep_print_held_locks(curr); | |
3299 | ||
3300 | printk("\nstack backtrace:\n"); | |
3301 | dump_stack(); | |
3302 | ||
3303 | return 0; | |
3304 | } | |
3305 | ||
3306 | static void | |
3307 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3308 | { | |
3309 | struct task_struct *curr = current; | |
3310 | struct held_lock *hlock, *prev_hlock; | |
3311 | struct lock_class_stats *stats; | |
3312 | unsigned int depth; | |
c7e78cff | 3313 | int i, contention_point, contending_point; |
f20786ff PZ |
3314 | |
3315 | depth = curr->lockdep_depth; | |
3316 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3317 | return; | |
3318 | ||
3319 | prev_hlock = NULL; | |
3320 | for (i = depth-1; i >= 0; i--) { | |
3321 | hlock = curr->held_locks + i; | |
3322 | /* | |
3323 | * We must not cross into another context: | |
3324 | */ | |
3325 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3326 | break; | |
bb97a91e | 3327 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3328 | goto found_it; |
3329 | prev_hlock = hlock; | |
3330 | } | |
3331 | print_lock_contention_bug(curr, lock, ip); | |
3332 | return; | |
3333 | ||
3334 | found_it: | |
bb97a91e PZ |
3335 | if (hlock->instance != lock) |
3336 | return; | |
3337 | ||
3365e779 | 3338 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3339 | |
c7e78cff PZ |
3340 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3341 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3342 | lock->ip); | |
f20786ff | 3343 | |
f82b217e | 3344 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3345 | if (contention_point < LOCKSTAT_POINTS) |
3346 | stats->contention_point[contention_point]++; | |
3347 | if (contending_point < LOCKSTAT_POINTS) | |
3348 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3349 | if (lock->cpu != smp_processor_id()) |
3350 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3351 | put_lock_stats(stats); |
3352 | } | |
3353 | ||
3354 | static void | |
c7e78cff | 3355 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3356 | { |
3357 | struct task_struct *curr = current; | |
3358 | struct held_lock *hlock, *prev_hlock; | |
3359 | struct lock_class_stats *stats; | |
3360 | unsigned int depth; | |
3365e779 | 3361 | u64 now, waittime = 0; |
96645678 | 3362 | int i, cpu; |
f20786ff PZ |
3363 | |
3364 | depth = curr->lockdep_depth; | |
3365 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3366 | return; | |
3367 | ||
3368 | prev_hlock = NULL; | |
3369 | for (i = depth-1; i >= 0; i--) { | |
3370 | hlock = curr->held_locks + i; | |
3371 | /* | |
3372 | * We must not cross into another context: | |
3373 | */ | |
3374 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3375 | break; | |
bb97a91e | 3376 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3377 | goto found_it; |
3378 | prev_hlock = hlock; | |
3379 | } | |
3380 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3381 | return; | |
3382 | ||
3383 | found_it: | |
bb97a91e PZ |
3384 | if (hlock->instance != lock) |
3385 | return; | |
3386 | ||
96645678 PZ |
3387 | cpu = smp_processor_id(); |
3388 | if (hlock->waittime_stamp) { | |
3365e779 | 3389 | now = lockstat_clock(); |
96645678 PZ |
3390 | waittime = now - hlock->waittime_stamp; |
3391 | hlock->holdtime_stamp = now; | |
3392 | } | |
f20786ff | 3393 | |
2062501a FW |
3394 | trace_lock_acquired(lock, ip, waittime); |
3395 | ||
f82b217e | 3396 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3397 | if (waittime) { |
3398 | if (hlock->read) | |
3399 | lock_time_inc(&stats->read_waittime, waittime); | |
3400 | else | |
3401 | lock_time_inc(&stats->write_waittime, waittime); | |
3402 | } | |
3403 | if (lock->cpu != cpu) | |
3404 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3405 | put_lock_stats(stats); |
96645678 PZ |
3406 | |
3407 | lock->cpu = cpu; | |
c7e78cff | 3408 | lock->ip = ip; |
f20786ff PZ |
3409 | } |
3410 | ||
3411 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3412 | { | |
3413 | unsigned long flags; | |
3414 | ||
efed792d PZ |
3415 | trace_lock_contended(lock, ip); |
3416 | ||
f20786ff PZ |
3417 | if (unlikely(!lock_stat)) |
3418 | return; | |
3419 | ||
3420 | if (unlikely(current->lockdep_recursion)) | |
3421 | return; | |
3422 | ||
3423 | raw_local_irq_save(flags); | |
3424 | check_flags(flags); | |
3425 | current->lockdep_recursion = 1; | |
3426 | __lock_contended(lock, ip); | |
3427 | current->lockdep_recursion = 0; | |
3428 | raw_local_irq_restore(flags); | |
3429 | } | |
3430 | EXPORT_SYMBOL_GPL(lock_contended); | |
3431 | ||
c7e78cff | 3432 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3433 | { |
3434 | unsigned long flags; | |
3435 | ||
3436 | if (unlikely(!lock_stat)) | |
3437 | return; | |
3438 | ||
3439 | if (unlikely(current->lockdep_recursion)) | |
3440 | return; | |
3441 | ||
3442 | raw_local_irq_save(flags); | |
3443 | check_flags(flags); | |
3444 | current->lockdep_recursion = 1; | |
c7e78cff | 3445 | __lock_acquired(lock, ip); |
f20786ff PZ |
3446 | current->lockdep_recursion = 0; |
3447 | raw_local_irq_restore(flags); | |
3448 | } | |
3449 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3450 | #endif | |
3451 | ||
fbb9ce95 IM |
3452 | /* |
3453 | * Used by the testsuite, sanitize the validator state | |
3454 | * after a simulated failure: | |
3455 | */ | |
3456 | ||
3457 | void lockdep_reset(void) | |
3458 | { | |
3459 | unsigned long flags; | |
23d95a03 | 3460 | int i; |
fbb9ce95 IM |
3461 | |
3462 | raw_local_irq_save(flags); | |
3463 | current->curr_chain_key = 0; | |
3464 | current->lockdep_depth = 0; | |
3465 | current->lockdep_recursion = 0; | |
3466 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3467 | nr_hardirq_chains = 0; | |
3468 | nr_softirq_chains = 0; | |
3469 | nr_process_chains = 0; | |
3470 | debug_locks = 1; | |
23d95a03 IM |
3471 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3472 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3473 | raw_local_irq_restore(flags); |
3474 | } | |
3475 | ||
3476 | static void zap_class(struct lock_class *class) | |
3477 | { | |
3478 | int i; | |
3479 | ||
3480 | /* | |
3481 | * Remove all dependencies this lock is | |
3482 | * involved in: | |
3483 | */ | |
3484 | for (i = 0; i < nr_list_entries; i++) { | |
3485 | if (list_entries[i].class == class) | |
3486 | list_del_rcu(&list_entries[i].entry); | |
3487 | } | |
3488 | /* | |
3489 | * Unhash the class and remove it from the all_lock_classes list: | |
3490 | */ | |
3491 | list_del_rcu(&class->hash_entry); | |
3492 | list_del_rcu(&class->lock_entry); | |
3493 | ||
8bfe0298 | 3494 | class->key = NULL; |
fbb9ce95 IM |
3495 | } |
3496 | ||
fabe874a | 3497 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3498 | { |
3499 | return addr >= start && addr < start + size; | |
3500 | } | |
3501 | ||
3502 | void lockdep_free_key_range(void *start, unsigned long size) | |
3503 | { | |
3504 | struct lock_class *class, *next; | |
3505 | struct list_head *head; | |
3506 | unsigned long flags; | |
3507 | int i; | |
5a26db5b | 3508 | int locked; |
fbb9ce95 IM |
3509 | |
3510 | raw_local_irq_save(flags); | |
5a26db5b | 3511 | locked = graph_lock(); |
fbb9ce95 IM |
3512 | |
3513 | /* | |
3514 | * Unhash all classes that were created by this module: | |
3515 | */ | |
3516 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3517 | head = classhash_table + i; | |
3518 | if (list_empty(head)) | |
3519 | continue; | |
fabe874a | 3520 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3521 | if (within(class->key, start, size)) |
3522 | zap_class(class); | |
fabe874a AV |
3523 | else if (within(class->name, start, size)) |
3524 | zap_class(class); | |
3525 | } | |
fbb9ce95 IM |
3526 | } |
3527 | ||
5a26db5b NP |
3528 | if (locked) |
3529 | graph_unlock(); | |
fbb9ce95 IM |
3530 | raw_local_irq_restore(flags); |
3531 | } | |
3532 | ||
3533 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3534 | { | |
d6d897ce | 3535 | struct lock_class *class, *next; |
fbb9ce95 IM |
3536 | struct list_head *head; |
3537 | unsigned long flags; | |
3538 | int i, j; | |
5a26db5b | 3539 | int locked; |
fbb9ce95 IM |
3540 | |
3541 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3542 | |
3543 | /* | |
d6d897ce IM |
3544 | * Remove all classes this lock might have: |
3545 | */ | |
3546 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3547 | /* | |
3548 | * If the class exists we look it up and zap it: | |
3549 | */ | |
3550 | class = look_up_lock_class(lock, j); | |
3551 | if (class) | |
3552 | zap_class(class); | |
3553 | } | |
3554 | /* | |
3555 | * Debug check: in the end all mapped classes should | |
3556 | * be gone. | |
fbb9ce95 | 3557 | */ |
5a26db5b | 3558 | locked = graph_lock(); |
fbb9ce95 IM |
3559 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3560 | head = classhash_table + i; | |
3561 | if (list_empty(head)) | |
3562 | continue; | |
3563 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3564 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3565 | if (debug_locks_off_graph_unlock()) |
3566 | WARN_ON(1); | |
d6d897ce | 3567 | goto out_restore; |
fbb9ce95 IM |
3568 | } |
3569 | } | |
3570 | } | |
5a26db5b NP |
3571 | if (locked) |
3572 | graph_unlock(); | |
d6d897ce IM |
3573 | |
3574 | out_restore: | |
fbb9ce95 IM |
3575 | raw_local_irq_restore(flags); |
3576 | } | |
3577 | ||
1499993c | 3578 | void lockdep_init(void) |
fbb9ce95 IM |
3579 | { |
3580 | int i; | |
3581 | ||
3582 | /* | |
3583 | * Some architectures have their own start_kernel() | |
3584 | * code which calls lockdep_init(), while we also | |
3585 | * call lockdep_init() from the start_kernel() itself, | |
3586 | * and we want to initialize the hashes only once: | |
3587 | */ | |
3588 | if (lockdep_initialized) | |
3589 | return; | |
3590 | ||
3591 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3592 | INIT_LIST_HEAD(classhash_table + i); | |
3593 | ||
3594 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3595 | INIT_LIST_HEAD(chainhash_table + i); | |
3596 | ||
3597 | lockdep_initialized = 1; | |
3598 | } | |
3599 | ||
3600 | void __init lockdep_info(void) | |
3601 | { | |
3602 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3603 | ||
b0788caf | 3604 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3605 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3606 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3607 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3608 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3609 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3610 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3611 | ||
3612 | printk(" memory used by lock dependency info: %lu kB\n", | |
3613 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3614 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3615 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3616 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 3617 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 3618 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 3619 | + sizeof(struct circular_queue) |
4dd861d6 | 3620 | #endif |
90629209 | 3621 | ) / 1024 |
4dd861d6 | 3622 | ); |
fbb9ce95 IM |
3623 | |
3624 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3625 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3626 | ||
3627 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3628 | if (lockdep_init_error) { |
3629 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3630 | printk("Call stack leading to lockdep invocation was:\n"); | |
3631 | print_stack_trace(&lockdep_init_trace, 0); | |
3632 | } | |
fbb9ce95 IM |
3633 | #endif |
3634 | } | |
3635 | ||
fbb9ce95 IM |
3636 | static void |
3637 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3638 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3639 | { |
3640 | if (!debug_locks_off()) | |
3641 | return; | |
3642 | if (debug_locks_silent) | |
3643 | return; | |
3644 | ||
3645 | printk("\n=========================\n"); | |
3646 | printk( "[ BUG: held lock freed! ]\n"); | |
3647 | printk( "-------------------------\n"); | |
3648 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3649 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3650 | print_lock(hlock); |
fbb9ce95 IM |
3651 | lockdep_print_held_locks(curr); |
3652 | ||
3653 | printk("\nstack backtrace:\n"); | |
3654 | dump_stack(); | |
3655 | } | |
3656 | ||
54561783 ON |
3657 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3658 | const void* lock_from, unsigned long lock_len) | |
3659 | { | |
3660 | return lock_from + lock_len <= mem_from || | |
3661 | mem_from + mem_len <= lock_from; | |
3662 | } | |
3663 | ||
fbb9ce95 IM |
3664 | /* |
3665 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3666 | * is destroyed or reinitialized - this code checks whether there is | |
3667 | * any held lock in the memory range of <from> to <to>: | |
3668 | */ | |
3669 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3670 | { | |
fbb9ce95 IM |
3671 | struct task_struct *curr = current; |
3672 | struct held_lock *hlock; | |
3673 | unsigned long flags; | |
3674 | int i; | |
3675 | ||
3676 | if (unlikely(!debug_locks)) | |
3677 | return; | |
3678 | ||
3679 | local_irq_save(flags); | |
3680 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3681 | hlock = curr->held_locks + i; | |
3682 | ||
54561783 ON |
3683 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3684 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3685 | continue; |
3686 | ||
54561783 | 3687 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3688 | break; |
3689 | } | |
3690 | local_irq_restore(flags); | |
3691 | } | |
ed07536e | 3692 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3693 | |
3694 | static void print_held_locks_bug(struct task_struct *curr) | |
3695 | { | |
3696 | if (!debug_locks_off()) | |
3697 | return; | |
3698 | if (debug_locks_silent) | |
3699 | return; | |
3700 | ||
3701 | printk("\n=====================================\n"); | |
3702 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3703 | printk( "-------------------------------------\n"); | |
3704 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3705 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3706 | lockdep_print_held_locks(curr); |
3707 | ||
3708 | printk("\nstack backtrace:\n"); | |
3709 | dump_stack(); | |
3710 | } | |
3711 | ||
3712 | void debug_check_no_locks_held(struct task_struct *task) | |
3713 | { | |
3714 | if (unlikely(task->lockdep_depth > 0)) | |
3715 | print_held_locks_bug(task); | |
3716 | } | |
3717 | ||
3718 | void debug_show_all_locks(void) | |
3719 | { | |
3720 | struct task_struct *g, *p; | |
3721 | int count = 10; | |
3722 | int unlock = 1; | |
3723 | ||
9c35dd7f JP |
3724 | if (unlikely(!debug_locks)) { |
3725 | printk("INFO: lockdep is turned off.\n"); | |
3726 | return; | |
3727 | } | |
fbb9ce95 IM |
3728 | printk("\nShowing all locks held in the system:\n"); |
3729 | ||
3730 | /* | |
3731 | * Here we try to get the tasklist_lock as hard as possible, | |
3732 | * if not successful after 2 seconds we ignore it (but keep | |
3733 | * trying). This is to enable a debug printout even if a | |
3734 | * tasklist_lock-holding task deadlocks or crashes. | |
3735 | */ | |
3736 | retry: | |
3737 | if (!read_trylock(&tasklist_lock)) { | |
3738 | if (count == 10) | |
3739 | printk("hm, tasklist_lock locked, retrying... "); | |
3740 | if (count) { | |
3741 | count--; | |
3742 | printk(" #%d", 10-count); | |
3743 | mdelay(200); | |
3744 | goto retry; | |
3745 | } | |
3746 | printk(" ignoring it.\n"); | |
3747 | unlock = 0; | |
46fec7ac | 3748 | } else { |
3749 | if (count != 10) | |
3750 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3751 | } |
fbb9ce95 IM |
3752 | |
3753 | do_each_thread(g, p) { | |
85684873 IM |
3754 | /* |
3755 | * It's not reliable to print a task's held locks | |
3756 | * if it's not sleeping (or if it's not the current | |
3757 | * task): | |
3758 | */ | |
3759 | if (p->state == TASK_RUNNING && p != current) | |
3760 | continue; | |
fbb9ce95 IM |
3761 | if (p->lockdep_depth) |
3762 | lockdep_print_held_locks(p); | |
3763 | if (!unlock) | |
3764 | if (read_trylock(&tasklist_lock)) | |
3765 | unlock = 1; | |
3766 | } while_each_thread(g, p); | |
3767 | ||
3768 | printk("\n"); | |
3769 | printk("=============================================\n\n"); | |
3770 | ||
3771 | if (unlock) | |
3772 | read_unlock(&tasklist_lock); | |
3773 | } | |
fbb9ce95 IM |
3774 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3775 | ||
82a1fcb9 IM |
3776 | /* |
3777 | * Careful: only use this function if you are sure that | |
3778 | * the task cannot run in parallel! | |
3779 | */ | |
3780 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3781 | { |
9c35dd7f JP |
3782 | if (unlikely(!debug_locks)) { |
3783 | printk("INFO: lockdep is turned off.\n"); | |
3784 | return; | |
3785 | } | |
fbb9ce95 IM |
3786 | lockdep_print_held_locks(task); |
3787 | } | |
82a1fcb9 IM |
3788 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3789 | ||
3790 | void debug_show_held_locks(struct task_struct *task) | |
3791 | { | |
3792 | __debug_show_held_locks(task); | |
3793 | } | |
fbb9ce95 | 3794 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3795 | |
3796 | void lockdep_sys_exit(void) | |
3797 | { | |
3798 | struct task_struct *curr = current; | |
3799 | ||
3800 | if (unlikely(curr->lockdep_depth)) { | |
3801 | if (!debug_locks_off()) | |
3802 | return; | |
3803 | printk("\n================================================\n"); | |
3804 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3805 | printk( "------------------------------------------------\n"); | |
3806 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3807 | curr->comm, curr->pid); | |
3808 | lockdep_print_held_locks(curr); | |
3809 | } | |
3810 | } |