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> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
af012961 | 47 | |
fbb9ce95 IM |
48 | #include <asm/sections.h> |
49 | ||
50 | #include "lockdep_internals.h" | |
51 | ||
a8d154b0 | 52 | #define CREATE_TRACE_POINTS |
67178767 | 53 | #include <trace/events/lock.h> |
a8d154b0 | 54 | |
f20786ff PZ |
55 | #ifdef CONFIG_PROVE_LOCKING |
56 | int prove_locking = 1; | |
57 | module_param(prove_locking, int, 0644); | |
58 | #else | |
59 | #define prove_locking 0 | |
60 | #endif | |
61 | ||
62 | #ifdef CONFIG_LOCK_STAT | |
63 | int lock_stat = 1; | |
64 | module_param(lock_stat, int, 0644); | |
65 | #else | |
66 | #define lock_stat 0 | |
67 | #endif | |
68 | ||
fbb9ce95 | 69 | /* |
74c383f1 IM |
70 | * lockdep_lock: protects the lockdep graph, the hashes and the |
71 | * class/list/hash allocators. | |
fbb9ce95 IM |
72 | * |
73 | * This is one of the rare exceptions where it's justified | |
74 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 75 | * code to recurse back into the lockdep code... |
fbb9ce95 | 76 | */ |
edc35bd7 | 77 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
78 | |
79 | static int graph_lock(void) | |
80 | { | |
0199c4e6 | 81 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
82 | /* |
83 | * Make sure that if another CPU detected a bug while | |
84 | * walking the graph we dont change it (while the other | |
85 | * CPU is busy printing out stuff with the graph lock | |
86 | * dropped already) | |
87 | */ | |
88 | if (!debug_locks) { | |
0199c4e6 | 89 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
90 | return 0; |
91 | } | |
bb065afb SR |
92 | /* prevent any recursions within lockdep from causing deadlocks */ |
93 | current->lockdep_recursion++; | |
74c383f1 IM |
94 | return 1; |
95 | } | |
96 | ||
97 | static inline int graph_unlock(void) | |
98 | { | |
0119fee4 PZ |
99 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
100 | /* | |
101 | * The lockdep graph lock isn't locked while we expect it to | |
102 | * be, we're confused now, bye! | |
103 | */ | |
381a2292 | 104 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 105 | } |
381a2292 | 106 | |
bb065afb | 107 | current->lockdep_recursion--; |
0199c4e6 | 108 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
109 | return 0; |
110 | } | |
111 | ||
112 | /* | |
113 | * Turn lock debugging off and return with 0 if it was off already, | |
114 | * and also release the graph lock: | |
115 | */ | |
116 | static inline int debug_locks_off_graph_unlock(void) | |
117 | { | |
118 | int ret = debug_locks_off(); | |
119 | ||
0199c4e6 | 120 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
121 | |
122 | return ret; | |
123 | } | |
fbb9ce95 IM |
124 | |
125 | static int lockdep_initialized; | |
126 | ||
127 | unsigned long nr_list_entries; | |
af012961 | 128 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 129 | |
fbb9ce95 IM |
130 | /* |
131 | * All data structures here are protected by the global debug_lock. | |
132 | * | |
133 | * Mutex key structs only get allocated, once during bootup, and never | |
134 | * get freed - this significantly simplifies the debugging code. | |
135 | */ | |
136 | unsigned long nr_lock_classes; | |
137 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
138 | ||
f82b217e DJ |
139 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
140 | { | |
141 | if (!hlock->class_idx) { | |
0119fee4 PZ |
142 | /* |
143 | * Someone passed in garbage, we give up. | |
144 | */ | |
f82b217e DJ |
145 | DEBUG_LOCKS_WARN_ON(1); |
146 | return NULL; | |
147 | } | |
148 | return lock_classes + hlock->class_idx - 1; | |
149 | } | |
150 | ||
f20786ff | 151 | #ifdef CONFIG_LOCK_STAT |
1871e52c TH |
152 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
153 | cpu_lock_stats); | |
f20786ff | 154 | |
3365e779 PZ |
155 | static inline u64 lockstat_clock(void) |
156 | { | |
c676329a | 157 | return local_clock(); |
3365e779 PZ |
158 | } |
159 | ||
c7e78cff | 160 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
161 | { |
162 | int i; | |
163 | ||
c7e78cff PZ |
164 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
165 | if (points[i] == 0) { | |
166 | points[i] = ip; | |
f20786ff PZ |
167 | break; |
168 | } | |
c7e78cff | 169 | if (points[i] == ip) |
f20786ff PZ |
170 | break; |
171 | } | |
172 | ||
173 | return i; | |
174 | } | |
175 | ||
3365e779 | 176 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
177 | { |
178 | if (time > lt->max) | |
179 | lt->max = time; | |
180 | ||
109d71c6 | 181 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
182 | lt->min = time; |
183 | ||
184 | lt->total += time; | |
185 | lt->nr++; | |
186 | } | |
187 | ||
c46261de PZ |
188 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
189 | { | |
109d71c6 FR |
190 | if (!src->nr) |
191 | return; | |
192 | ||
193 | if (src->max > dst->max) | |
194 | dst->max = src->max; | |
195 | ||
196 | if (src->min < dst->min || !dst->nr) | |
197 | dst->min = src->min; | |
198 | ||
c46261de PZ |
199 | dst->total += src->total; |
200 | dst->nr += src->nr; | |
201 | } | |
202 | ||
203 | struct lock_class_stats lock_stats(struct lock_class *class) | |
204 | { | |
205 | struct lock_class_stats stats; | |
206 | int cpu, i; | |
207 | ||
208 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
209 | for_each_possible_cpu(cpu) { | |
210 | struct lock_class_stats *pcs = | |
1871e52c | 211 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
212 | |
213 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
214 | stats.contention_point[i] += pcs->contention_point[i]; | |
215 | ||
c7e78cff PZ |
216 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
217 | stats.contending_point[i] += pcs->contending_point[i]; | |
218 | ||
c46261de PZ |
219 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
220 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
221 | ||
222 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
223 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
224 | |
225 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
226 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
227 | } |
228 | ||
229 | return stats; | |
230 | } | |
231 | ||
232 | void clear_lock_stats(struct lock_class *class) | |
233 | { | |
234 | int cpu; | |
235 | ||
236 | for_each_possible_cpu(cpu) { | |
237 | struct lock_class_stats *cpu_stats = | |
1871e52c | 238 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
239 | |
240 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
241 | } | |
242 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 243 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
244 | } |
245 | ||
f20786ff PZ |
246 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
247 | { | |
1871e52c | 248 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
249 | } |
250 | ||
251 | static void put_lock_stats(struct lock_class_stats *stats) | |
252 | { | |
1871e52c | 253 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
254 | } |
255 | ||
256 | static void lock_release_holdtime(struct held_lock *hlock) | |
257 | { | |
258 | struct lock_class_stats *stats; | |
3365e779 | 259 | u64 holdtime; |
f20786ff PZ |
260 | |
261 | if (!lock_stat) | |
262 | return; | |
263 | ||
3365e779 | 264 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 265 | |
f82b217e | 266 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
267 | if (hlock->read) |
268 | lock_time_inc(&stats->read_holdtime, holdtime); | |
269 | else | |
270 | lock_time_inc(&stats->write_holdtime, holdtime); | |
271 | put_lock_stats(stats); | |
272 | } | |
273 | #else | |
274 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
275 | { | |
276 | } | |
277 | #endif | |
278 | ||
fbb9ce95 IM |
279 | /* |
280 | * We keep a global list of all lock classes. The list only grows, | |
281 | * never shrinks. The list is only accessed with the lockdep | |
282 | * spinlock lock held. | |
283 | */ | |
284 | LIST_HEAD(all_lock_classes); | |
285 | ||
286 | /* | |
287 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
288 | */ | |
289 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
290 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 291 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
292 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
293 | ||
294 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
295 | ||
fbb9ce95 IM |
296 | /* |
297 | * We put the lock dependency chains into a hash-table as well, to cache | |
298 | * their existence: | |
299 | */ | |
300 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
301 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 302 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
303 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
304 | ||
305 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
306 | ||
307 | /* | |
308 | * The hash key of the lock dependency chains is a hash itself too: | |
309 | * it's a hash of all locks taken up to that lock, including that lock. | |
310 | * It's a 64-bit hash, because it's important for the keys to be | |
311 | * unique. | |
312 | */ | |
313 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
314 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
315 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
316 | (key2)) |
317 | ||
1d09daa5 | 318 | void lockdep_off(void) |
fbb9ce95 IM |
319 | { |
320 | current->lockdep_recursion++; | |
321 | } | |
fbb9ce95 IM |
322 | EXPORT_SYMBOL(lockdep_off); |
323 | ||
1d09daa5 | 324 | void lockdep_on(void) |
fbb9ce95 IM |
325 | { |
326 | current->lockdep_recursion--; | |
327 | } | |
fbb9ce95 IM |
328 | EXPORT_SYMBOL(lockdep_on); |
329 | ||
fbb9ce95 IM |
330 | /* |
331 | * Debugging switches: | |
332 | */ | |
333 | ||
334 | #define VERBOSE 0 | |
33e94e96 | 335 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
336 | |
337 | #if VERBOSE | |
338 | # define HARDIRQ_VERBOSE 1 | |
339 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 340 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
341 | #else |
342 | # define HARDIRQ_VERBOSE 0 | |
343 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 344 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
345 | #endif |
346 | ||
cf40bd16 | 347 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
348 | /* |
349 | * Quick filtering for interesting events: | |
350 | */ | |
351 | static int class_filter(struct lock_class *class) | |
352 | { | |
f9829cce AK |
353 | #if 0 |
354 | /* Example */ | |
fbb9ce95 | 355 | if (class->name_version == 1 && |
f9829cce | 356 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
357 | return 1; |
358 | if (class->name_version == 1 && | |
f9829cce | 359 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 360 | return 1; |
f9829cce | 361 | #endif |
a6640897 IM |
362 | /* Filter everything else. 1 would be to allow everything else */ |
363 | return 0; | |
fbb9ce95 IM |
364 | } |
365 | #endif | |
366 | ||
367 | static int verbose(struct lock_class *class) | |
368 | { | |
369 | #if VERBOSE | |
370 | return class_filter(class); | |
371 | #endif | |
372 | return 0; | |
373 | } | |
374 | ||
fbb9ce95 IM |
375 | /* |
376 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 377 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
378 | */ |
379 | unsigned long nr_stack_trace_entries; | |
380 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
381 | ||
382 | static int save_trace(struct stack_trace *trace) | |
383 | { | |
384 | trace->nr_entries = 0; | |
385 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
386 | trace->entries = stack_trace + nr_stack_trace_entries; | |
387 | ||
5a1b3999 | 388 | trace->skip = 3; |
5a1b3999 | 389 | |
ab1b6f03 | 390 | save_stack_trace(trace); |
fbb9ce95 | 391 | |
4f84f433 PZ |
392 | /* |
393 | * Some daft arches put -1 at the end to indicate its a full trace. | |
394 | * | |
395 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
396 | * complete trace that maxes out the entries provided will be reported | |
397 | * as incomplete, friggin useless </rant> | |
398 | */ | |
ea5b41f9 LT |
399 | if (trace->nr_entries != 0 && |
400 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
401 | trace->nr_entries--; |
402 | ||
fbb9ce95 IM |
403 | trace->max_entries = trace->nr_entries; |
404 | ||
405 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 406 | |
4f84f433 | 407 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
408 | if (!debug_locks_off_graph_unlock()) |
409 | return 0; | |
410 | ||
411 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
412 | printk("turning off the locking correctness validator.\n"); | |
413 | dump_stack(); | |
414 | ||
fbb9ce95 IM |
415 | return 0; |
416 | } | |
417 | ||
418 | return 1; | |
419 | } | |
420 | ||
421 | unsigned int nr_hardirq_chains; | |
422 | unsigned int nr_softirq_chains; | |
423 | unsigned int nr_process_chains; | |
424 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
425 | |
426 | #ifdef CONFIG_DEBUG_LOCKDEP | |
427 | /* | |
428 | * We cannot printk in early bootup code. Not even early_printk() | |
429 | * might work. So we mark any initialization errors and printk | |
430 | * about it later on, in lockdep_info(). | |
431 | */ | |
432 | static int lockdep_init_error; | |
c71063c9 JB |
433 | static unsigned long lockdep_init_trace_data[20]; |
434 | static struct stack_trace lockdep_init_trace = { | |
435 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
436 | .entries = lockdep_init_trace_data, | |
437 | }; | |
fbb9ce95 IM |
438 | |
439 | /* | |
440 | * Various lockdep statistics: | |
441 | */ | |
bd6d29c2 | 442 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
443 | #endif |
444 | ||
445 | /* | |
446 | * Locking printouts: | |
447 | */ | |
448 | ||
fabe9c42 | 449 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
450 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
451 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
452 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
453 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 454 | |
fbb9ce95 IM |
455 | static const char *usage_str[] = |
456 | { | |
fabe9c42 PZ |
457 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
458 | #include "lockdep_states.h" | |
459 | #undef LOCKDEP_STATE | |
460 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
461 | }; |
462 | ||
463 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
464 | { | |
ffb45122 | 465 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
466 | } |
467 | ||
3ff176ca | 468 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 469 | { |
3ff176ca PZ |
470 | return 1UL << bit; |
471 | } | |
fbb9ce95 | 472 | |
3ff176ca PZ |
473 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
474 | { | |
475 | char c = '.'; | |
476 | ||
477 | if (class->usage_mask & lock_flag(bit + 2)) | |
478 | c = '+'; | |
479 | if (class->usage_mask & lock_flag(bit)) { | |
480 | c = '-'; | |
481 | if (class->usage_mask & lock_flag(bit + 2)) | |
482 | c = '?'; | |
fbb9ce95 IM |
483 | } |
484 | ||
3ff176ca PZ |
485 | return c; |
486 | } | |
cf40bd16 | 487 | |
f510b233 | 488 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 489 | { |
f510b233 | 490 | int i = 0; |
cf40bd16 | 491 | |
f510b233 PZ |
492 | #define LOCKDEP_STATE(__STATE) \ |
493 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
494 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
495 | #include "lockdep_states.h" | |
496 | #undef LOCKDEP_STATE | |
497 | ||
498 | usage[i] = '\0'; | |
fbb9ce95 IM |
499 | } |
500 | ||
3003eba3 SR |
501 | static int __print_lock_name(struct lock_class *class) |
502 | { | |
503 | char str[KSYM_NAME_LEN]; | |
504 | const char *name; | |
505 | ||
506 | name = class->name; | |
507 | if (!name) | |
508 | name = __get_key_name(class->key, str); | |
509 | ||
510 | return printk("%s", name); | |
511 | } | |
512 | ||
fbb9ce95 IM |
513 | static void print_lock_name(struct lock_class *class) |
514 | { | |
f510b233 | 515 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
516 | const char *name; |
517 | ||
f510b233 | 518 | get_usage_chars(class, usage); |
fbb9ce95 IM |
519 | |
520 | name = class->name; | |
521 | if (!name) { | |
522 | name = __get_key_name(class->key, str); | |
523 | printk(" (%s", name); | |
524 | } else { | |
525 | printk(" (%s", name); | |
526 | if (class->name_version > 1) | |
527 | printk("#%d", class->name_version); | |
528 | if (class->subclass) | |
529 | printk("/%d", class->subclass); | |
530 | } | |
f510b233 | 531 | printk("){%s}", usage); |
fbb9ce95 IM |
532 | } |
533 | ||
534 | static void print_lockdep_cache(struct lockdep_map *lock) | |
535 | { | |
536 | const char *name; | |
9281acea | 537 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
538 | |
539 | name = lock->name; | |
540 | if (!name) | |
541 | name = __get_key_name(lock->key->subkeys, str); | |
542 | ||
543 | printk("%s", name); | |
544 | } | |
545 | ||
546 | static void print_lock(struct held_lock *hlock) | |
547 | { | |
f82b217e | 548 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
549 | printk(", at: "); |
550 | print_ip_sym(hlock->acquire_ip); | |
551 | } | |
552 | ||
553 | static void lockdep_print_held_locks(struct task_struct *curr) | |
554 | { | |
555 | int i, depth = curr->lockdep_depth; | |
556 | ||
557 | if (!depth) { | |
ba25f9dc | 558 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
559 | return; |
560 | } | |
561 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 562 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
563 | |
564 | for (i = 0; i < depth; i++) { | |
565 | printk(" #%d: ", i); | |
566 | print_lock(curr->held_locks + i); | |
567 | } | |
568 | } | |
fbb9ce95 | 569 | |
8e18257d PZ |
570 | static void print_kernel_version(void) |
571 | { | |
572 | printk("%s %.*s\n", init_utsname()->release, | |
573 | (int)strcspn(init_utsname()->version, " "), | |
574 | init_utsname()->version); | |
575 | } | |
576 | ||
577 | static int very_verbose(struct lock_class *class) | |
578 | { | |
579 | #if VERY_VERBOSE | |
580 | return class_filter(class); | |
581 | #endif | |
582 | return 0; | |
583 | } | |
584 | ||
fbb9ce95 | 585 | /* |
8e18257d | 586 | * Is this the address of a static object: |
fbb9ce95 | 587 | */ |
8e18257d | 588 | static int static_obj(void *obj) |
fbb9ce95 | 589 | { |
8e18257d PZ |
590 | unsigned long start = (unsigned long) &_stext, |
591 | end = (unsigned long) &_end, | |
592 | addr = (unsigned long) obj; | |
8e18257d | 593 | |
fbb9ce95 | 594 | /* |
8e18257d | 595 | * static variable? |
fbb9ce95 | 596 | */ |
8e18257d PZ |
597 | if ((addr >= start) && (addr < end)) |
598 | return 1; | |
fbb9ce95 | 599 | |
2a9ad18d MF |
600 | if (arch_is_kernel_data(addr)) |
601 | return 1; | |
602 | ||
fbb9ce95 | 603 | /* |
10fad5e4 | 604 | * in-kernel percpu var? |
fbb9ce95 | 605 | */ |
10fad5e4 TH |
606 | if (is_kernel_percpu_address(addr)) |
607 | return 1; | |
fbb9ce95 | 608 | |
8e18257d | 609 | /* |
10fad5e4 | 610 | * module static or percpu var? |
8e18257d | 611 | */ |
10fad5e4 | 612 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a DJ |
613 | } |
614 | ||
fbb9ce95 | 615 | /* |
8e18257d PZ |
616 | * To make lock name printouts unique, we calculate a unique |
617 | * class->name_version generation counter: | |
fbb9ce95 | 618 | */ |
8e18257d | 619 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 620 | { |
8e18257d PZ |
621 | struct lock_class *class; |
622 | int count = 0; | |
fbb9ce95 | 623 | |
8e18257d | 624 | if (!new_class->name) |
fbb9ce95 IM |
625 | return 0; |
626 | ||
8e18257d PZ |
627 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
628 | if (new_class->key - new_class->subclass == class->key) | |
629 | return class->name_version; | |
630 | if (class->name && !strcmp(class->name, new_class->name)) | |
631 | count = max(count, class->name_version); | |
632 | } | |
fbb9ce95 | 633 | |
8e18257d | 634 | return count + 1; |
fbb9ce95 IM |
635 | } |
636 | ||
8e18257d PZ |
637 | /* |
638 | * Register a lock's class in the hash-table, if the class is not present | |
639 | * yet. Otherwise we look it up. We cache the result in the lock object | |
640 | * itself, so actual lookup of the hash should be once per lock object. | |
641 | */ | |
642 | static inline struct lock_class * | |
643 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 644 | { |
8e18257d PZ |
645 | struct lockdep_subclass_key *key; |
646 | struct list_head *hash_head; | |
647 | struct lock_class *class; | |
fbb9ce95 | 648 | |
8e18257d PZ |
649 | #ifdef CONFIG_DEBUG_LOCKDEP |
650 | /* | |
651 | * If the architecture calls into lockdep before initializing | |
652 | * the hashes then we'll warn about it later. (we cannot printk | |
653 | * right now) | |
654 | */ | |
655 | if (unlikely(!lockdep_initialized)) { | |
656 | lockdep_init(); | |
657 | lockdep_init_error = 1; | |
c71063c9 | 658 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
659 | } |
660 | #endif | |
fbb9ce95 | 661 | |
4ba053c0 HM |
662 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
663 | debug_locks_off(); | |
664 | printk(KERN_ERR | |
665 | "BUG: looking up invalid subclass: %u\n", subclass); | |
666 | printk(KERN_ERR | |
667 | "turning off the locking correctness validator.\n"); | |
668 | dump_stack(); | |
669 | return NULL; | |
670 | } | |
671 | ||
8e18257d PZ |
672 | /* |
673 | * Static locks do not have their class-keys yet - for them the key | |
674 | * is the lock object itself: | |
675 | */ | |
676 | if (unlikely(!lock->key)) | |
677 | lock->key = (void *)lock; | |
fbb9ce95 | 678 | |
8e18257d PZ |
679 | /* |
680 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
681 | * lock_class_key variable is passed in through the mutex_init() | |
682 | * (or spin_lock_init()) call - which acts as the key. For static | |
683 | * locks we use the lock object itself as the key. | |
684 | */ | |
4b32d0a4 PZ |
685 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
686 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 687 | |
8e18257d | 688 | key = lock->key->subkeys + subclass; |
ca268c69 | 689 | |
8e18257d | 690 | hash_head = classhashentry(key); |
74c383f1 | 691 | |
8e18257d PZ |
692 | /* |
693 | * We can walk the hash lockfree, because the hash only | |
694 | * grows, and we are careful when adding entries to the end: | |
695 | */ | |
4b32d0a4 PZ |
696 | list_for_each_entry(class, hash_head, hash_entry) { |
697 | if (class->key == key) { | |
0119fee4 PZ |
698 | /* |
699 | * Huh! same key, different name? Did someone trample | |
700 | * on some memory? We're most confused. | |
701 | */ | |
4b32d0a4 | 702 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 703 | return class; |
4b32d0a4 PZ |
704 | } |
705 | } | |
fbb9ce95 | 706 | |
8e18257d | 707 | return NULL; |
fbb9ce95 IM |
708 | } |
709 | ||
710 | /* | |
8e18257d PZ |
711 | * Register a lock's class in the hash-table, if the class is not present |
712 | * yet. Otherwise we look it up. We cache the result in the lock object | |
713 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 714 | */ |
8e18257d PZ |
715 | static inline struct lock_class * |
716 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 717 | { |
8e18257d PZ |
718 | struct lockdep_subclass_key *key; |
719 | struct list_head *hash_head; | |
720 | struct lock_class *class; | |
721 | unsigned long flags; | |
722 | ||
723 | class = look_up_lock_class(lock, subclass); | |
724 | if (likely(class)) | |
725 | return class; | |
726 | ||
727 | /* | |
728 | * Debug-check: all keys must be persistent! | |
729 | */ | |
730 | if (!static_obj(lock->key)) { | |
731 | debug_locks_off(); | |
732 | printk("INFO: trying to register non-static key.\n"); | |
733 | printk("the code is fine but needs lockdep annotation.\n"); | |
734 | printk("turning off the locking correctness validator.\n"); | |
735 | dump_stack(); | |
736 | ||
737 | return NULL; | |
738 | } | |
739 | ||
740 | key = lock->key->subkeys + subclass; | |
741 | hash_head = classhashentry(key); | |
742 | ||
743 | raw_local_irq_save(flags); | |
744 | if (!graph_lock()) { | |
745 | raw_local_irq_restore(flags); | |
746 | return NULL; | |
747 | } | |
748 | /* | |
749 | * We have to do the hash-walk again, to avoid races | |
750 | * with another CPU: | |
751 | */ | |
752 | list_for_each_entry(class, hash_head, hash_entry) | |
753 | if (class->key == key) | |
754 | goto out_unlock_set; | |
755 | /* | |
756 | * Allocate a new key from the static array, and add it to | |
757 | * the hash: | |
758 | */ | |
759 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
760 | if (!debug_locks_off_graph_unlock()) { | |
761 | raw_local_irq_restore(flags); | |
762 | return NULL; | |
763 | } | |
764 | raw_local_irq_restore(flags); | |
765 | ||
766 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
767 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 768 | dump_stack(); |
8e18257d PZ |
769 | return NULL; |
770 | } | |
771 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 772 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
773 | class->key = key; |
774 | class->name = lock->name; | |
775 | class->subclass = subclass; | |
776 | INIT_LIST_HEAD(&class->lock_entry); | |
777 | INIT_LIST_HEAD(&class->locks_before); | |
778 | INIT_LIST_HEAD(&class->locks_after); | |
779 | class->name_version = count_matching_names(class); | |
780 | /* | |
781 | * We use RCU's safe list-add method to make | |
782 | * parallel walking of the hash-list safe: | |
783 | */ | |
784 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
785 | /* |
786 | * Add it to the global list of classes: | |
787 | */ | |
788 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
789 | |
790 | if (verbose(class)) { | |
791 | graph_unlock(); | |
792 | raw_local_irq_restore(flags); | |
793 | ||
794 | printk("\nnew class %p: %s", class->key, class->name); | |
795 | if (class->name_version > 1) | |
796 | printk("#%d", class->name_version); | |
797 | printk("\n"); | |
798 | dump_stack(); | |
799 | ||
800 | raw_local_irq_save(flags); | |
801 | if (!graph_lock()) { | |
802 | raw_local_irq_restore(flags); | |
803 | return NULL; | |
804 | } | |
805 | } | |
806 | out_unlock_set: | |
807 | graph_unlock(); | |
808 | raw_local_irq_restore(flags); | |
809 | ||
810 | if (!subclass || force) | |
62016250 HM |
811 | lock->class_cache[0] = class; |
812 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
813 | lock->class_cache[subclass] = class; | |
8e18257d | 814 | |
0119fee4 PZ |
815 | /* |
816 | * Hash collision, did we smoke some? We found a class with a matching | |
817 | * hash but the subclass -- which is hashed in -- didn't match. | |
818 | */ | |
8e18257d PZ |
819 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
820 | return NULL; | |
821 | ||
822 | return class; | |
823 | } | |
824 | ||
825 | #ifdef CONFIG_PROVE_LOCKING | |
826 | /* | |
827 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
828 | * with NULL on failure) | |
829 | */ | |
830 | static struct lock_list *alloc_list_entry(void) | |
831 | { | |
832 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
833 | if (!debug_locks_off_graph_unlock()) | |
834 | return NULL; | |
835 | ||
836 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
837 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 838 | dump_stack(); |
8e18257d PZ |
839 | return NULL; |
840 | } | |
841 | return list_entries + nr_list_entries++; | |
842 | } | |
843 | ||
844 | /* | |
845 | * Add a new dependency to the head of the list: | |
846 | */ | |
847 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
4726f2a6 YZ |
848 | struct list_head *head, unsigned long ip, |
849 | int distance, struct stack_trace *trace) | |
8e18257d PZ |
850 | { |
851 | struct lock_list *entry; | |
852 | /* | |
853 | * Lock not present yet - get a new dependency struct and | |
854 | * add it to the list: | |
855 | */ | |
856 | entry = alloc_list_entry(); | |
857 | if (!entry) | |
858 | return 0; | |
859 | ||
74870172 ZY |
860 | entry->class = this; |
861 | entry->distance = distance; | |
4726f2a6 | 862 | entry->trace = *trace; |
8e18257d PZ |
863 | /* |
864 | * Since we never remove from the dependency list, the list can | |
865 | * be walked lockless by other CPUs, it's only allocation | |
866 | * that must be protected by the spinlock. But this also means | |
867 | * we must make new entries visible only once writes to the | |
868 | * entry become visible - hence the RCU op: | |
869 | */ | |
870 | list_add_tail_rcu(&entry->entry, head); | |
871 | ||
872 | return 1; | |
873 | } | |
874 | ||
98c33edd PZ |
875 | /* |
876 | * For good efficiency of modular, we use power of 2 | |
877 | */ | |
af012961 PZ |
878 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
879 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
880 | ||
98c33edd PZ |
881 | /* |
882 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
883 | * breadth-first search(BFS)algorithem, by which we can build |
884 | * the shortest path from the next lock to be acquired to the | |
885 | * previous held lock if there is a circular between them. | |
98c33edd | 886 | */ |
af012961 PZ |
887 | struct circular_queue { |
888 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
889 | unsigned int front, rear; | |
890 | }; | |
891 | ||
892 | static struct circular_queue lock_cq; | |
af012961 | 893 | |
12f3dfd0 | 894 | unsigned int max_bfs_queue_depth; |
af012961 | 895 | |
e351b660 ML |
896 | static unsigned int lockdep_dependency_gen_id; |
897 | ||
af012961 PZ |
898 | static inline void __cq_init(struct circular_queue *cq) |
899 | { | |
900 | cq->front = cq->rear = 0; | |
e351b660 | 901 | lockdep_dependency_gen_id++; |
af012961 PZ |
902 | } |
903 | ||
904 | static inline int __cq_empty(struct circular_queue *cq) | |
905 | { | |
906 | return (cq->front == cq->rear); | |
907 | } | |
908 | ||
909 | static inline int __cq_full(struct circular_queue *cq) | |
910 | { | |
911 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
912 | } | |
913 | ||
914 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
915 | { | |
916 | if (__cq_full(cq)) | |
917 | return -1; | |
918 | ||
919 | cq->element[cq->rear] = elem; | |
920 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
921 | return 0; | |
922 | } | |
923 | ||
924 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
925 | { | |
926 | if (__cq_empty(cq)) | |
927 | return -1; | |
928 | ||
929 | *elem = cq->element[cq->front]; | |
930 | cq->front = (cq->front + 1) & CQ_MASK; | |
931 | return 0; | |
932 | } | |
933 | ||
934 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
935 | { | |
936 | return (cq->rear - cq->front) & CQ_MASK; | |
937 | } | |
938 | ||
939 | static inline void mark_lock_accessed(struct lock_list *lock, | |
940 | struct lock_list *parent) | |
941 | { | |
942 | unsigned long nr; | |
98c33edd | 943 | |
af012961 | 944 | nr = lock - list_entries; |
0119fee4 | 945 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 946 | lock->parent = parent; |
e351b660 | 947 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
948 | } |
949 | ||
950 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
951 | { | |
952 | unsigned long nr; | |
98c33edd | 953 | |
af012961 | 954 | nr = lock - list_entries; |
0119fee4 | 955 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 956 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
957 | } |
958 | ||
959 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
960 | { | |
961 | return child->parent; | |
962 | } | |
963 | ||
964 | static inline int get_lock_depth(struct lock_list *child) | |
965 | { | |
966 | int depth = 0; | |
967 | struct lock_list *parent; | |
968 | ||
969 | while ((parent = get_lock_parent(child))) { | |
970 | child = parent; | |
971 | depth++; | |
972 | } | |
973 | return depth; | |
974 | } | |
975 | ||
9e2d551e | 976 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
977 | void *data, |
978 | int (*match)(struct lock_list *entry, void *data), | |
979 | struct lock_list **target_entry, | |
980 | int forward) | |
c94aa5ca ML |
981 | { |
982 | struct lock_list *entry; | |
d588e461 | 983 | struct list_head *head; |
c94aa5ca ML |
984 | struct circular_queue *cq = &lock_cq; |
985 | int ret = 1; | |
986 | ||
9e2d551e | 987 | if (match(source_entry, data)) { |
c94aa5ca ML |
988 | *target_entry = source_entry; |
989 | ret = 0; | |
990 | goto exit; | |
991 | } | |
992 | ||
d588e461 ML |
993 | if (forward) |
994 | head = &source_entry->class->locks_after; | |
995 | else | |
996 | head = &source_entry->class->locks_before; | |
997 | ||
998 | if (list_empty(head)) | |
999 | goto exit; | |
1000 | ||
1001 | __cq_init(cq); | |
c94aa5ca ML |
1002 | __cq_enqueue(cq, (unsigned long)source_entry); |
1003 | ||
1004 | while (!__cq_empty(cq)) { | |
1005 | struct lock_list *lock; | |
c94aa5ca ML |
1006 | |
1007 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1008 | ||
1009 | if (!lock->class) { | |
1010 | ret = -2; | |
1011 | goto exit; | |
1012 | } | |
1013 | ||
1014 | if (forward) | |
1015 | head = &lock->class->locks_after; | |
1016 | else | |
1017 | head = &lock->class->locks_before; | |
1018 | ||
1019 | list_for_each_entry(entry, head, entry) { | |
1020 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 1021 | unsigned int cq_depth; |
c94aa5ca | 1022 | mark_lock_accessed(entry, lock); |
9e2d551e | 1023 | if (match(entry, data)) { |
c94aa5ca ML |
1024 | *target_entry = entry; |
1025 | ret = 0; | |
1026 | goto exit; | |
1027 | } | |
1028 | ||
1029 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1030 | ret = -1; | |
1031 | goto exit; | |
1032 | } | |
12f3dfd0 ML |
1033 | cq_depth = __cq_get_elem_count(cq); |
1034 | if (max_bfs_queue_depth < cq_depth) | |
1035 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1036 | } |
1037 | } | |
1038 | } | |
1039 | exit: | |
1040 | return ret; | |
1041 | } | |
1042 | ||
d7aaba14 | 1043 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1044 | void *data, |
1045 | int (*match)(struct lock_list *entry, void *data), | |
1046 | struct lock_list **target_entry) | |
c94aa5ca | 1047 | { |
9e2d551e | 1048 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1049 | |
1050 | } | |
1051 | ||
d7aaba14 | 1052 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1053 | void *data, |
1054 | int (*match)(struct lock_list *entry, void *data), | |
1055 | struct lock_list **target_entry) | |
c94aa5ca | 1056 | { |
9e2d551e | 1057 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1058 | |
1059 | } | |
1060 | ||
8e18257d PZ |
1061 | /* |
1062 | * Recursive, forwards-direction lock-dependency checking, used for | |
1063 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1064 | * checking. | |
8e18257d | 1065 | */ |
8e18257d PZ |
1066 | |
1067 | /* | |
1068 | * Print a dependency chain entry (this is only done when a deadlock | |
1069 | * has been detected): | |
1070 | */ | |
1071 | static noinline int | |
24208ca7 | 1072 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1073 | { |
1074 | if (debug_locks_silent) | |
1075 | return 0; | |
1076 | printk("\n-> #%u", depth); | |
1077 | print_lock_name(target->class); | |
1078 | printk(":\n"); | |
1079 | print_stack_trace(&target->trace, 6); | |
1080 | ||
1081 | return 0; | |
1082 | } | |
1083 | ||
f4185812 SR |
1084 | static void |
1085 | print_circular_lock_scenario(struct held_lock *src, | |
1086 | struct held_lock *tgt, | |
1087 | struct lock_list *prt) | |
1088 | { | |
1089 | struct lock_class *source = hlock_class(src); | |
1090 | struct lock_class *target = hlock_class(tgt); | |
1091 | struct lock_class *parent = prt->class; | |
1092 | ||
1093 | /* | |
1094 | * A direct locking problem where unsafe_class lock is taken | |
1095 | * directly by safe_class lock, then all we need to show | |
1096 | * is the deadlock scenario, as it is obvious that the | |
1097 | * unsafe lock is taken under the safe lock. | |
1098 | * | |
1099 | * But if there is a chain instead, where the safe lock takes | |
1100 | * an intermediate lock (middle_class) where this lock is | |
1101 | * not the same as the safe lock, then the lock chain is | |
1102 | * used to describe the problem. Otherwise we would need | |
1103 | * to show a different CPU case for each link in the chain | |
1104 | * from the safe_class lock to the unsafe_class lock. | |
1105 | */ | |
1106 | if (parent != source) { | |
1107 | printk("Chain exists of:\n "); | |
1108 | __print_lock_name(source); | |
1109 | printk(" --> "); | |
1110 | __print_lock_name(parent); | |
1111 | printk(" --> "); | |
1112 | __print_lock_name(target); | |
1113 | printk("\n\n"); | |
1114 | } | |
1115 | ||
1116 | printk(" Possible unsafe locking scenario:\n\n"); | |
1117 | printk(" CPU0 CPU1\n"); | |
1118 | printk(" ---- ----\n"); | |
1119 | printk(" lock("); | |
1120 | __print_lock_name(target); | |
1121 | printk(");\n"); | |
1122 | printk(" lock("); | |
1123 | __print_lock_name(parent); | |
1124 | printk(");\n"); | |
1125 | printk(" lock("); | |
1126 | __print_lock_name(target); | |
1127 | printk(");\n"); | |
1128 | printk(" lock("); | |
1129 | __print_lock_name(source); | |
1130 | printk(");\n"); | |
1131 | printk("\n *** DEADLOCK ***\n\n"); | |
1132 | } | |
1133 | ||
8e18257d PZ |
1134 | /* |
1135 | * When a circular dependency is detected, print the | |
1136 | * header first: | |
1137 | */ | |
1138 | static noinline int | |
db0002a3 ML |
1139 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1140 | struct held_lock *check_src, | |
1141 | struct held_lock *check_tgt) | |
8e18257d PZ |
1142 | { |
1143 | struct task_struct *curr = current; | |
1144 | ||
c94aa5ca | 1145 | if (debug_locks_silent) |
8e18257d PZ |
1146 | return 0; |
1147 | ||
b3fbab05 PM |
1148 | printk("\n"); |
1149 | printk("======================================================\n"); | |
1150 | printk("[ INFO: possible circular locking dependency detected ]\n"); | |
8e18257d | 1151 | print_kernel_version(); |
b3fbab05 | 1152 | printk("-------------------------------------------------------\n"); |
8e18257d | 1153 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1154 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1155 | print_lock(check_src); |
8e18257d | 1156 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1157 | print_lock(check_tgt); |
8e18257d PZ |
1158 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1159 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1160 | ||
1161 | print_circular_bug_entry(entry, depth); | |
1162 | ||
1163 | return 0; | |
1164 | } | |
1165 | ||
9e2d551e ML |
1166 | static inline int class_equal(struct lock_list *entry, void *data) |
1167 | { | |
1168 | return entry->class == data; | |
1169 | } | |
1170 | ||
db0002a3 ML |
1171 | static noinline int print_circular_bug(struct lock_list *this, |
1172 | struct lock_list *target, | |
1173 | struct held_lock *check_src, | |
1174 | struct held_lock *check_tgt) | |
8e18257d PZ |
1175 | { |
1176 | struct task_struct *curr = current; | |
c94aa5ca | 1177 | struct lock_list *parent; |
f4185812 | 1178 | struct lock_list *first_parent; |
24208ca7 | 1179 | int depth; |
8e18257d | 1180 | |
c94aa5ca | 1181 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1182 | return 0; |
1183 | ||
db0002a3 | 1184 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1185 | return 0; |
1186 | ||
c94aa5ca ML |
1187 | depth = get_lock_depth(target); |
1188 | ||
db0002a3 | 1189 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1190 | |
1191 | parent = get_lock_parent(target); | |
f4185812 | 1192 | first_parent = parent; |
c94aa5ca ML |
1193 | |
1194 | while (parent) { | |
1195 | print_circular_bug_entry(parent, --depth); | |
1196 | parent = get_lock_parent(parent); | |
1197 | } | |
8e18257d PZ |
1198 | |
1199 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1200 | print_circular_lock_scenario(check_src, check_tgt, |
1201 | first_parent); | |
1202 | ||
8e18257d PZ |
1203 | lockdep_print_held_locks(curr); |
1204 | ||
1205 | printk("\nstack backtrace:\n"); | |
1206 | dump_stack(); | |
1207 | ||
1208 | return 0; | |
1209 | } | |
1210 | ||
db0002a3 ML |
1211 | static noinline int print_bfs_bug(int ret) |
1212 | { | |
1213 | if (!debug_locks_off_graph_unlock()) | |
1214 | return 0; | |
1215 | ||
0119fee4 PZ |
1216 | /* |
1217 | * Breadth-first-search failed, graph got corrupted? | |
1218 | */ | |
db0002a3 ML |
1219 | WARN(1, "lockdep bfs error:%d\n", ret); |
1220 | ||
1221 | return 0; | |
1222 | } | |
1223 | ||
ef681026 | 1224 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1225 | { |
ef681026 ML |
1226 | (*(unsigned long *)data)++; |
1227 | return 0; | |
1228 | } | |
419ca3f1 | 1229 | |
ef681026 ML |
1230 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1231 | { | |
1232 | unsigned long count = 0; | |
1233 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1234 | |
ef681026 | 1235 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1236 | |
ef681026 | 1237 | return count; |
419ca3f1 | 1238 | } |
419ca3f1 DM |
1239 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1240 | { | |
1241 | unsigned long ret, flags; | |
ef681026 ML |
1242 | struct lock_list this; |
1243 | ||
1244 | this.parent = NULL; | |
1245 | this.class = class; | |
419ca3f1 DM |
1246 | |
1247 | local_irq_save(flags); | |
0199c4e6 | 1248 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1249 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1250 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1251 | local_irq_restore(flags); |
1252 | ||
1253 | return ret; | |
1254 | } | |
1255 | ||
ef681026 | 1256 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1257 | { |
ef681026 ML |
1258 | unsigned long count = 0; |
1259 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1260 | |
ef681026 | 1261 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1262 | |
ef681026 | 1263 | return count; |
419ca3f1 DM |
1264 | } |
1265 | ||
1266 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1267 | { | |
1268 | unsigned long ret, flags; | |
ef681026 ML |
1269 | struct lock_list this; |
1270 | ||
1271 | this.parent = NULL; | |
1272 | this.class = class; | |
419ca3f1 DM |
1273 | |
1274 | local_irq_save(flags); | |
0199c4e6 | 1275 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1276 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1277 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1278 | local_irq_restore(flags); |
1279 | ||
1280 | return ret; | |
1281 | } | |
1282 | ||
8e18257d PZ |
1283 | /* |
1284 | * Prove that the dependency graph starting at <entry> can not | |
1285 | * lead to <target>. Print an error and return 0 if it does. | |
1286 | */ | |
1287 | static noinline int | |
db0002a3 ML |
1288 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1289 | struct lock_list **target_entry) | |
8e18257d | 1290 | { |
db0002a3 | 1291 | int result; |
8e18257d | 1292 | |
bd6d29c2 | 1293 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1294 | |
d7aaba14 | 1295 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1296 | |
db0002a3 ML |
1297 | return result; |
1298 | } | |
c94aa5ca | 1299 | |
81d68a96 | 1300 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1301 | /* |
1302 | * Forwards and backwards subgraph searching, for the purposes of | |
1303 | * proving that two subgraphs can be connected by a new dependency | |
1304 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1305 | */ | |
fbb9ce95 | 1306 | |
d7aaba14 ML |
1307 | static inline int usage_match(struct lock_list *entry, void *bit) |
1308 | { | |
1309 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1310 | } | |
1311 | ||
1312 | ||
1313 | ||
fbb9ce95 IM |
1314 | /* |
1315 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1316 | * at @root->class that matches @bit. |
fbb9ce95 | 1317 | * |
d7aaba14 ML |
1318 | * Return 0 if such a node exists in the subgraph, and put that node |
1319 | * into *@target_entry. | |
fbb9ce95 | 1320 | * |
d7aaba14 ML |
1321 | * Return 1 otherwise and keep *@target_entry unchanged. |
1322 | * Return <0 on error. | |
fbb9ce95 | 1323 | */ |
d7aaba14 ML |
1324 | static int |
1325 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1326 | struct lock_list **target_entry) | |
fbb9ce95 | 1327 | { |
d7aaba14 | 1328 | int result; |
fbb9ce95 | 1329 | |
bd6d29c2 | 1330 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1331 | |
d7aaba14 ML |
1332 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1333 | ||
1334 | return result; | |
fbb9ce95 IM |
1335 | } |
1336 | ||
1337 | /* | |
1338 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1339 | * at @root->class that matches @bit. |
fbb9ce95 | 1340 | * |
d7aaba14 ML |
1341 | * Return 0 if such a node exists in the subgraph, and put that node |
1342 | * into *@target_entry. | |
fbb9ce95 | 1343 | * |
d7aaba14 ML |
1344 | * Return 1 otherwise and keep *@target_entry unchanged. |
1345 | * Return <0 on error. | |
fbb9ce95 | 1346 | */ |
d7aaba14 ML |
1347 | static int |
1348 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1349 | struct lock_list **target_entry) | |
fbb9ce95 | 1350 | { |
d7aaba14 | 1351 | int result; |
fbb9ce95 | 1352 | |
bd6d29c2 | 1353 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1354 | |
d7aaba14 | 1355 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1356 | |
d7aaba14 | 1357 | return result; |
fbb9ce95 IM |
1358 | } |
1359 | ||
af012961 PZ |
1360 | static void print_lock_class_header(struct lock_class *class, int depth) |
1361 | { | |
1362 | int bit; | |
1363 | ||
1364 | printk("%*s->", depth, ""); | |
1365 | print_lock_name(class); | |
1366 | printk(" ops: %lu", class->ops); | |
1367 | printk(" {\n"); | |
1368 | ||
1369 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1370 | if (class->usage_mask & (1 << bit)) { | |
1371 | int len = depth; | |
1372 | ||
1373 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1374 | len += printk(" at:\n"); | |
1375 | print_stack_trace(class->usage_traces + bit, len); | |
1376 | } | |
1377 | } | |
1378 | printk("%*s }\n", depth, ""); | |
1379 | ||
1380 | printk("%*s ... key at: ",depth,""); | |
1381 | print_ip_sym((unsigned long)class->key); | |
1382 | } | |
1383 | ||
1384 | /* | |
1385 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1386 | */ | |
1387 | static void __used | |
1388 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1389 | struct lock_list *root) | |
1390 | { | |
1391 | struct lock_list *entry = leaf; | |
1392 | int depth; | |
1393 | ||
1394 | /*compute depth from generated tree by BFS*/ | |
1395 | depth = get_lock_depth(leaf); | |
1396 | ||
1397 | do { | |
1398 | print_lock_class_header(entry->class, depth); | |
1399 | printk("%*s ... acquired at:\n", depth, ""); | |
1400 | print_stack_trace(&entry->trace, 2); | |
1401 | printk("\n"); | |
1402 | ||
1403 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1404 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1405 | break; |
1406 | } | |
1407 | ||
1408 | entry = get_lock_parent(entry); | |
1409 | depth--; | |
1410 | } while (entry && (depth >= 0)); | |
1411 | ||
1412 | return; | |
1413 | } | |
d7aaba14 | 1414 | |
3003eba3 SR |
1415 | static void |
1416 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1417 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1418 | struct lock_class *prev_class, |
1419 | struct lock_class *next_class) | |
3003eba3 SR |
1420 | { |
1421 | struct lock_class *safe_class = safe_entry->class; | |
1422 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1423 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1424 | |
1425 | if (middle_class == safe_class) | |
dad3d743 | 1426 | middle_class = next_class; |
3003eba3 SR |
1427 | |
1428 | /* | |
1429 | * A direct locking problem where unsafe_class lock is taken | |
1430 | * directly by safe_class lock, then all we need to show | |
1431 | * is the deadlock scenario, as it is obvious that the | |
1432 | * unsafe lock is taken under the safe lock. | |
1433 | * | |
1434 | * But if there is a chain instead, where the safe lock takes | |
1435 | * an intermediate lock (middle_class) where this lock is | |
1436 | * not the same as the safe lock, then the lock chain is | |
1437 | * used to describe the problem. Otherwise we would need | |
1438 | * to show a different CPU case for each link in the chain | |
1439 | * from the safe_class lock to the unsafe_class lock. | |
1440 | */ | |
1441 | if (middle_class != unsafe_class) { | |
1442 | printk("Chain exists of:\n "); | |
1443 | __print_lock_name(safe_class); | |
1444 | printk(" --> "); | |
1445 | __print_lock_name(middle_class); | |
1446 | printk(" --> "); | |
1447 | __print_lock_name(unsafe_class); | |
1448 | printk("\n\n"); | |
1449 | } | |
1450 | ||
1451 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1452 | printk(" CPU0 CPU1\n"); | |
1453 | printk(" ---- ----\n"); | |
1454 | printk(" lock("); | |
1455 | __print_lock_name(unsafe_class); | |
1456 | printk(");\n"); | |
1457 | printk(" local_irq_disable();\n"); | |
1458 | printk(" lock("); | |
1459 | __print_lock_name(safe_class); | |
1460 | printk(");\n"); | |
1461 | printk(" lock("); | |
1462 | __print_lock_name(middle_class); | |
1463 | printk(");\n"); | |
1464 | printk(" <Interrupt>\n"); | |
1465 | printk(" lock("); | |
1466 | __print_lock_name(safe_class); | |
1467 | printk(");\n"); | |
1468 | printk("\n *** DEADLOCK ***\n\n"); | |
1469 | } | |
1470 | ||
fbb9ce95 IM |
1471 | static int |
1472 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1473 | struct lock_list *prev_root, |
1474 | struct lock_list *next_root, | |
1475 | struct lock_list *backwards_entry, | |
1476 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1477 | struct held_lock *prev, |
1478 | struct held_lock *next, | |
1479 | enum lock_usage_bit bit1, | |
1480 | enum lock_usage_bit bit2, | |
1481 | const char *irqclass) | |
1482 | { | |
74c383f1 | 1483 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1484 | return 0; |
1485 | ||
b3fbab05 PM |
1486 | printk("\n"); |
1487 | printk("======================================================\n"); | |
1488 | printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
fbb9ce95 | 1489 | irqclass, irqclass); |
99de055a | 1490 | print_kernel_version(); |
b3fbab05 | 1491 | printk("------------------------------------------------------\n"); |
fbb9ce95 | 1492 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1493 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1494 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1495 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1496 | curr->hardirqs_enabled, | |
1497 | curr->softirqs_enabled); | |
1498 | print_lock(next); | |
1499 | ||
1500 | printk("\nand this task is already holding:\n"); | |
1501 | print_lock(prev); | |
1502 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1503 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1504 | printk(" ->"); |
f82b217e | 1505 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1506 | printk("\n"); |
1507 | ||
1508 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1509 | irqclass); | |
24208ca7 | 1510 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1511 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1512 | ||
24208ca7 | 1513 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1514 | |
1515 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1516 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1517 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1518 | printk("..."); | |
1519 | ||
24208ca7 | 1520 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1521 | |
1522 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1523 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1524 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1525 | |
fbb9ce95 IM |
1526 | lockdep_print_held_locks(curr); |
1527 | ||
24208ca7 ML |
1528 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1529 | printk(" and the holding lock:\n"); | |
1530 | if (!save_trace(&prev_root->trace)) | |
1531 | return 0; | |
1532 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1533 | |
24208ca7 ML |
1534 | printk("\nthe dependencies between the lock to be acquired"); |
1535 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1536 | if (!save_trace(&next_root->trace)) | |
1537 | return 0; | |
1538 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1539 | |
1540 | printk("\nstack backtrace:\n"); | |
1541 | dump_stack(); | |
1542 | ||
1543 | return 0; | |
1544 | } | |
1545 | ||
1546 | static int | |
1547 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1548 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1549 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1550 | { | |
1551 | int ret; | |
24208ca7 | 1552 | struct lock_list this, that; |
d7aaba14 | 1553 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1554 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1555 | |
1556 | this.parent = NULL; | |
1557 | ||
1558 | this.class = hlock_class(prev); | |
1559 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1560 | if (ret < 0) |
1561 | return print_bfs_bug(ret); | |
1562 | if (ret == 1) | |
1563 | return ret; | |
d7aaba14 | 1564 | |
24208ca7 ML |
1565 | that.parent = NULL; |
1566 | that.class = hlock_class(next); | |
1567 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1568 | if (ret < 0) |
1569 | return print_bfs_bug(ret); | |
1570 | if (ret == 1) | |
1571 | return ret; | |
fbb9ce95 | 1572 | |
24208ca7 ML |
1573 | return print_bad_irq_dependency(curr, &this, &that, |
1574 | target_entry, target_entry1, | |
1575 | prev, next, | |
fbb9ce95 IM |
1576 | bit_backwards, bit_forwards, irqclass); |
1577 | } | |
1578 | ||
4f367d8a PZ |
1579 | static const char *state_names[] = { |
1580 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1581 | __stringify(__STATE), |
4f367d8a PZ |
1582 | #include "lockdep_states.h" |
1583 | #undef LOCKDEP_STATE | |
1584 | }; | |
1585 | ||
1586 | static const char *state_rnames[] = { | |
1587 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1588 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1589 | #include "lockdep_states.h" |
1590 | #undef LOCKDEP_STATE | |
1591 | }; | |
1592 | ||
1593 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1594 | { |
4f367d8a PZ |
1595 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1596 | } | |
8e18257d | 1597 | |
4f367d8a PZ |
1598 | static int exclusive_bit(int new_bit) |
1599 | { | |
8e18257d | 1600 | /* |
4f367d8a PZ |
1601 | * USED_IN |
1602 | * USED_IN_READ | |
1603 | * ENABLED | |
1604 | * ENABLED_READ | |
1605 | * | |
1606 | * bit 0 - write/read | |
1607 | * bit 1 - used_in/enabled | |
1608 | * bit 2+ state | |
8e18257d | 1609 | */ |
4f367d8a PZ |
1610 | |
1611 | int state = new_bit & ~3; | |
1612 | int dir = new_bit & 2; | |
8e18257d PZ |
1613 | |
1614 | /* | |
4f367d8a | 1615 | * keep state, bit flip the direction and strip read. |
8e18257d | 1616 | */ |
4f367d8a PZ |
1617 | return state | (dir ^ 2); |
1618 | } | |
1619 | ||
1620 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1621 | struct held_lock *next, enum lock_usage_bit bit) | |
1622 | { | |
8e18257d | 1623 | /* |
4f367d8a PZ |
1624 | * Prove that the new dependency does not connect a hardirq-safe |
1625 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1626 | * the backwards-subgraph starting at <prev>, and the |
1627 | * forwards-subgraph starting at <next>: | |
1628 | */ | |
4f367d8a PZ |
1629 | if (!check_usage(curr, prev, next, bit, |
1630 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1631 | return 0; |
1632 | ||
4f367d8a PZ |
1633 | bit++; /* _READ */ |
1634 | ||
cf40bd16 | 1635 | /* |
4f367d8a PZ |
1636 | * Prove that the new dependency does not connect a hardirq-safe-read |
1637 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1638 | * the backwards-subgraph starting at <prev>, and the |
1639 | * forwards-subgraph starting at <next>: | |
1640 | */ | |
4f367d8a PZ |
1641 | if (!check_usage(curr, prev, next, bit, |
1642 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1643 | return 0; |
1644 | ||
4f367d8a PZ |
1645 | return 1; |
1646 | } | |
1647 | ||
1648 | static int | |
1649 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1650 | struct held_lock *next) | |
1651 | { | |
1652 | #define LOCKDEP_STATE(__STATE) \ | |
1653 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1654 | return 0; |
4f367d8a PZ |
1655 | #include "lockdep_states.h" |
1656 | #undef LOCKDEP_STATE | |
cf40bd16 | 1657 | |
8e18257d PZ |
1658 | return 1; |
1659 | } | |
1660 | ||
1661 | static void inc_chains(void) | |
1662 | { | |
1663 | if (current->hardirq_context) | |
1664 | nr_hardirq_chains++; | |
1665 | else { | |
1666 | if (current->softirq_context) | |
1667 | nr_softirq_chains++; | |
1668 | else | |
1669 | nr_process_chains++; | |
1670 | } | |
1671 | } | |
1672 | ||
1673 | #else | |
1674 | ||
1675 | static inline int | |
1676 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1677 | struct held_lock *next) | |
1678 | { | |
1679 | return 1; | |
1680 | } | |
1681 | ||
1682 | static inline void inc_chains(void) | |
1683 | { | |
1684 | nr_process_chains++; | |
1685 | } | |
1686 | ||
fbb9ce95 IM |
1687 | #endif |
1688 | ||
48702ecf SR |
1689 | static void |
1690 | print_deadlock_scenario(struct held_lock *nxt, | |
1691 | struct held_lock *prv) | |
1692 | { | |
1693 | struct lock_class *next = hlock_class(nxt); | |
1694 | struct lock_class *prev = hlock_class(prv); | |
1695 | ||
1696 | printk(" Possible unsafe locking scenario:\n\n"); | |
1697 | printk(" CPU0\n"); | |
1698 | printk(" ----\n"); | |
1699 | printk(" lock("); | |
1700 | __print_lock_name(prev); | |
1701 | printk(");\n"); | |
1702 | printk(" lock("); | |
1703 | __print_lock_name(next); | |
1704 | printk(");\n"); | |
1705 | printk("\n *** DEADLOCK ***\n\n"); | |
1706 | printk(" May be due to missing lock nesting notation\n\n"); | |
1707 | } | |
1708 | ||
fbb9ce95 IM |
1709 | static int |
1710 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1711 | struct held_lock *next) | |
1712 | { | |
74c383f1 | 1713 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1714 | return 0; |
1715 | ||
b3fbab05 PM |
1716 | printk("\n"); |
1717 | printk("=============================================\n"); | |
1718 | printk("[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1719 | print_kernel_version(); |
b3fbab05 | 1720 | printk("---------------------------------------------\n"); |
fbb9ce95 | 1721 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1722 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1723 | print_lock(next); |
1724 | printk("\nbut task is already holding lock:\n"); | |
1725 | print_lock(prev); | |
1726 | ||
1727 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1728 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1729 | lockdep_print_held_locks(curr); |
1730 | ||
1731 | printk("\nstack backtrace:\n"); | |
1732 | dump_stack(); | |
1733 | ||
1734 | return 0; | |
1735 | } | |
1736 | ||
1737 | /* | |
1738 | * Check whether we are holding such a class already. | |
1739 | * | |
1740 | * (Note that this has to be done separately, because the graph cannot | |
1741 | * detect such classes of deadlocks.) | |
1742 | * | |
1743 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1744 | */ | |
1745 | static int | |
1746 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1747 | struct lockdep_map *next_instance, int read) | |
1748 | { | |
1749 | struct held_lock *prev; | |
7531e2f3 | 1750 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1751 | int i; |
1752 | ||
1753 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1754 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1755 | |
1756 | if (prev->instance == next->nest_lock) | |
1757 | nest = prev; | |
1758 | ||
f82b217e | 1759 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1760 | continue; |
7531e2f3 | 1761 | |
fbb9ce95 IM |
1762 | /* |
1763 | * Allow read-after-read recursion of the same | |
6c9076ec | 1764 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1765 | */ |
6c9076ec | 1766 | if ((read == 2) && prev->read) |
fbb9ce95 | 1767 | return 2; |
7531e2f3 PZ |
1768 | |
1769 | /* | |
1770 | * We're holding the nest_lock, which serializes this lock's | |
1771 | * nesting behaviour. | |
1772 | */ | |
1773 | if (nest) | |
1774 | return 2; | |
1775 | ||
fbb9ce95 IM |
1776 | return print_deadlock_bug(curr, prev, next); |
1777 | } | |
1778 | return 1; | |
1779 | } | |
1780 | ||
1781 | /* | |
1782 | * There was a chain-cache miss, and we are about to add a new dependency | |
1783 | * to a previous lock. We recursively validate the following rules: | |
1784 | * | |
1785 | * - would the adding of the <prev> -> <next> dependency create a | |
1786 | * circular dependency in the graph? [== circular deadlock] | |
1787 | * | |
1788 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1789 | * (in the full backwards-subgraph starting at <prev>) with any | |
1790 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1791 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1792 | * | |
1793 | * - does the new prev->next dependency connect any softirq-safe lock | |
1794 | * (in the full backwards-subgraph starting at <prev>) with any | |
1795 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1796 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1797 | * | |
1798 | * any of these scenarios could lead to a deadlock. | |
1799 | * | |
1800 | * Then if all the validations pass, we add the forwards and backwards | |
1801 | * dependency. | |
1802 | */ | |
1803 | static int | |
1804 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
4726f2a6 | 1805 | struct held_lock *next, int distance, int trylock_loop) |
fbb9ce95 IM |
1806 | { |
1807 | struct lock_list *entry; | |
1808 | int ret; | |
db0002a3 ML |
1809 | struct lock_list this; |
1810 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1811 | /* |
1812 | * Static variable, serialized by the graph_lock(). | |
1813 | * | |
1814 | * We use this static variable to save the stack trace in case | |
1815 | * we call into this function multiple times due to encountering | |
1816 | * trylocks in the held lock stack. | |
1817 | */ | |
1818 | static struct stack_trace trace; | |
fbb9ce95 IM |
1819 | |
1820 | /* | |
1821 | * Prove that the new <prev> -> <next> dependency would not | |
1822 | * create a circular dependency in the graph. (We do this by | |
1823 | * forward-recursing into the graph starting at <next>, and | |
1824 | * checking whether we can reach <prev>.) | |
1825 | * | |
1826 | * We are using global variables to control the recursion, to | |
1827 | * keep the stackframe size of the recursive functions low: | |
1828 | */ | |
db0002a3 ML |
1829 | this.class = hlock_class(next); |
1830 | this.parent = NULL; | |
1831 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1832 | if (unlikely(!ret)) | |
1833 | return print_circular_bug(&this, target_entry, next, prev); | |
1834 | else if (unlikely(ret < 0)) | |
1835 | return print_bfs_bug(ret); | |
c94aa5ca | 1836 | |
8e18257d | 1837 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1838 | return 0; |
1839 | ||
fbb9ce95 IM |
1840 | /* |
1841 | * For recursive read-locks we do all the dependency checks, | |
1842 | * but we dont store read-triggered dependencies (only | |
1843 | * write-triggered dependencies). This ensures that only the | |
1844 | * write-side dependencies matter, and that if for example a | |
1845 | * write-lock never takes any other locks, then the reads are | |
1846 | * equivalent to a NOP. | |
1847 | */ | |
1848 | if (next->read == 2 || prev->read == 2) | |
1849 | return 1; | |
1850 | /* | |
1851 | * Is the <prev> -> <next> dependency already present? | |
1852 | * | |
1853 | * (this may occur even though this is a new chain: consider | |
1854 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1855 | * chains - the second one will be new, but L1 already has | |
1856 | * L2 added to its dependency list, due to the first chain.) | |
1857 | */ | |
f82b217e DJ |
1858 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1859 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1860 | if (distance == 1) |
1861 | entry->distance = 1; | |
fbb9ce95 | 1862 | return 2; |
068135e6 | 1863 | } |
fbb9ce95 IM |
1864 | } |
1865 | ||
4726f2a6 YZ |
1866 | if (!trylock_loop && !save_trace(&trace)) |
1867 | return 0; | |
1868 | ||
fbb9ce95 IM |
1869 | /* |
1870 | * Ok, all validations passed, add the new lock | |
1871 | * to the previous lock's dependency list: | |
1872 | */ | |
f82b217e DJ |
1873 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1874 | &hlock_class(prev)->locks_after, | |
4726f2a6 | 1875 | next->acquire_ip, distance, &trace); |
068135e6 | 1876 | |
fbb9ce95 IM |
1877 | if (!ret) |
1878 | return 0; | |
910b1b2e | 1879 | |
f82b217e DJ |
1880 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1881 | &hlock_class(next)->locks_before, | |
4726f2a6 | 1882 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1883 | if (!ret) |
1884 | return 0; | |
fbb9ce95 IM |
1885 | |
1886 | /* | |
8e18257d PZ |
1887 | * Debugging printouts: |
1888 | */ | |
f82b217e | 1889 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1890 | graph_unlock(); |
1891 | printk("\n new dependency: "); | |
f82b217e | 1892 | print_lock_name(hlock_class(prev)); |
8e18257d | 1893 | printk(" => "); |
f82b217e | 1894 | print_lock_name(hlock_class(next)); |
8e18257d | 1895 | printk("\n"); |
fbb9ce95 | 1896 | dump_stack(); |
8e18257d | 1897 | return graph_lock(); |
fbb9ce95 | 1898 | } |
8e18257d PZ |
1899 | return 1; |
1900 | } | |
fbb9ce95 | 1901 | |
8e18257d PZ |
1902 | /* |
1903 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1904 | * The ones that are relevant are (in increasing distance from curr): | |
1905 | * all consecutive trylock entries and the final non-trylock entry - or | |
1906 | * the end of this context's lock-chain - whichever comes first. | |
1907 | */ | |
1908 | static int | |
1909 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1910 | { | |
1911 | int depth = curr->lockdep_depth; | |
4726f2a6 | 1912 | int trylock_loop = 0; |
8e18257d | 1913 | struct held_lock *hlock; |
d6d897ce | 1914 | |
fbb9ce95 | 1915 | /* |
8e18257d PZ |
1916 | * Debugging checks. |
1917 | * | |
1918 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1919 | */ |
8e18257d PZ |
1920 | if (!depth) |
1921 | goto out_bug; | |
fbb9ce95 | 1922 | /* |
8e18257d PZ |
1923 | * At least two relevant locks must exist for this |
1924 | * to be a head: | |
fbb9ce95 | 1925 | */ |
8e18257d PZ |
1926 | if (curr->held_locks[depth].irq_context != |
1927 | curr->held_locks[depth-1].irq_context) | |
1928 | goto out_bug; | |
74c383f1 | 1929 | |
8e18257d PZ |
1930 | for (;;) { |
1931 | int distance = curr->lockdep_depth - depth + 1; | |
1932 | hlock = curr->held_locks + depth-1; | |
1933 | /* | |
1934 | * Only non-recursive-read entries get new dependencies | |
1935 | * added: | |
1936 | */ | |
1937 | if (hlock->read != 2) { | |
4726f2a6 YZ |
1938 | if (!check_prev_add(curr, hlock, next, |
1939 | distance, trylock_loop)) | |
8e18257d PZ |
1940 | return 0; |
1941 | /* | |
1942 | * Stop after the first non-trylock entry, | |
1943 | * as non-trylock entries have added their | |
1944 | * own direct dependencies already, so this | |
1945 | * lock is connected to them indirectly: | |
1946 | */ | |
1947 | if (!hlock->trylock) | |
1948 | break; | |
74c383f1 | 1949 | } |
8e18257d PZ |
1950 | depth--; |
1951 | /* | |
1952 | * End of lock-stack? | |
1953 | */ | |
1954 | if (!depth) | |
1955 | break; | |
1956 | /* | |
1957 | * Stop the search if we cross into another context: | |
1958 | */ | |
1959 | if (curr->held_locks[depth].irq_context != | |
1960 | curr->held_locks[depth-1].irq_context) | |
1961 | break; | |
4726f2a6 | 1962 | trylock_loop = 1; |
fbb9ce95 | 1963 | } |
8e18257d PZ |
1964 | return 1; |
1965 | out_bug: | |
1966 | if (!debug_locks_off_graph_unlock()) | |
1967 | return 0; | |
fbb9ce95 | 1968 | |
0119fee4 PZ |
1969 | /* |
1970 | * Clearly we all shouldn't be here, but since we made it we | |
1971 | * can reliable say we messed up our state. See the above two | |
1972 | * gotos for reasons why we could possibly end up here. | |
1973 | */ | |
8e18257d | 1974 | WARN_ON(1); |
fbb9ce95 | 1975 | |
8e18257d | 1976 | return 0; |
fbb9ce95 IM |
1977 | } |
1978 | ||
8e18257d | 1979 | unsigned long nr_lock_chains; |
443cd507 | 1980 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1981 | int nr_chain_hlocks; |
443cd507 HY |
1982 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1983 | ||
1984 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1985 | { | |
1986 | return lock_classes + chain_hlocks[chain->base + i]; | |
1987 | } | |
8e18257d | 1988 | |
fbb9ce95 IM |
1989 | /* |
1990 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1991 | * add it and return 1 - in this case the new dependency chain is |
1992 | * validated. If the key is already hashed, return 0. | |
1993 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1994 | */ |
443cd507 HY |
1995 | static inline int lookup_chain_cache(struct task_struct *curr, |
1996 | struct held_lock *hlock, | |
1997 | u64 chain_key) | |
fbb9ce95 | 1998 | { |
f82b217e | 1999 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
2000 | struct list_head *hash_head = chainhashentry(chain_key); |
2001 | struct lock_chain *chain; | |
443cd507 | 2002 | struct held_lock *hlock_curr, *hlock_next; |
e0944ee6 | 2003 | int i, j; |
fbb9ce95 | 2004 | |
0119fee4 PZ |
2005 | /* |
2006 | * We might need to take the graph lock, ensure we've got IRQs | |
2007 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2008 | * lockdep won't complain about its own locking errors. | |
2009 | */ | |
381a2292 JP |
2010 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2011 | return 0; | |
fbb9ce95 IM |
2012 | /* |
2013 | * We can walk it lock-free, because entries only get added | |
2014 | * to the hash: | |
2015 | */ | |
2016 | list_for_each_entry(chain, hash_head, entry) { | |
2017 | if (chain->chain_key == chain_key) { | |
2018 | cache_hit: | |
bd6d29c2 | 2019 | debug_atomic_inc(chain_lookup_hits); |
81fc685a | 2020 | if (very_verbose(class)) |
755cd900 AM |
2021 | printk("\nhash chain already cached, key: " |
2022 | "%016Lx tail class: [%p] %s\n", | |
2023 | (unsigned long long)chain_key, | |
2024 | class->key, class->name); | |
fbb9ce95 IM |
2025 | return 0; |
2026 | } | |
2027 | } | |
81fc685a | 2028 | if (very_verbose(class)) |
755cd900 AM |
2029 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2030 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2031 | /* |
2032 | * Allocate a new chain entry from the static array, and add | |
2033 | * it to the hash: | |
2034 | */ | |
74c383f1 IM |
2035 | if (!graph_lock()) |
2036 | return 0; | |
fbb9ce95 IM |
2037 | /* |
2038 | * We have to walk the chain again locked - to avoid duplicates: | |
2039 | */ | |
2040 | list_for_each_entry(chain, hash_head, entry) { | |
2041 | if (chain->chain_key == chain_key) { | |
74c383f1 | 2042 | graph_unlock(); |
fbb9ce95 IM |
2043 | goto cache_hit; |
2044 | } | |
2045 | } | |
2046 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2047 | if (!debug_locks_off_graph_unlock()) |
2048 | return 0; | |
2049 | ||
fbb9ce95 IM |
2050 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
2051 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2052 | dump_stack(); |
fbb9ce95 IM |
2053 | return 0; |
2054 | } | |
2055 | chain = lock_chains + nr_lock_chains++; | |
2056 | chain->chain_key = chain_key; | |
443cd507 HY |
2057 | chain->irq_context = hlock->irq_context; |
2058 | /* Find the first held_lock of current chain */ | |
2059 | hlock_next = hlock; | |
2060 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2061 | hlock_curr = curr->held_locks + i; | |
2062 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
2063 | break; | |
2064 | hlock_next = hlock; | |
2065 | } | |
2066 | i++; | |
2067 | chain->depth = curr->lockdep_depth + 1 - i; | |
e0944ee6 SR |
2068 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2069 | chain->base = nr_chain_hlocks; | |
2070 | nr_chain_hlocks += chain->depth; | |
443cd507 | 2071 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2072 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2073 | chain_hlocks[chain->base + j] = lock_id; |
2074 | } | |
2075 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2076 | } | |
fbb9ce95 | 2077 | list_add_tail_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2078 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2079 | inc_chains(); |
2080 | ||
2081 | return 1; | |
2082 | } | |
2083 | ||
2084 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2085 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2086 | { |
2087 | /* | |
2088 | * Trylock needs to maintain the stack of held locks, but it | |
2089 | * does not add new dependencies, because trylock can be done | |
2090 | * in any order. | |
2091 | * | |
2092 | * We look up the chain_key and do the O(N^2) check and update of | |
2093 | * the dependencies only if this is a new dependency chain. | |
2094 | * (If lookup_chain_cache() returns with 1 it acquires | |
2095 | * graph_lock for us) | |
2096 | */ | |
2097 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 2098 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2099 | /* |
2100 | * Check whether last held lock: | |
2101 | * | |
2102 | * - is irq-safe, if this lock is irq-unsafe | |
2103 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2104 | * | |
2105 | * And check whether the new lock's dependency graph | |
2106 | * could lead back to the previous lock. | |
2107 | * | |
2108 | * any of these scenarios could lead to a deadlock. If | |
2109 | * All validations | |
2110 | */ | |
2111 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2112 | ||
2113 | if (!ret) | |
2114 | return 0; | |
2115 | /* | |
2116 | * Mark recursive read, as we jump over it when | |
2117 | * building dependencies (just like we jump over | |
2118 | * trylock entries): | |
2119 | */ | |
2120 | if (ret == 2) | |
2121 | hlock->read = 2; | |
2122 | /* | |
2123 | * Add dependency only if this lock is not the head | |
2124 | * of the chain, and if it's not a secondary read-lock: | |
2125 | */ | |
2126 | if (!chain_head && ret != 2) | |
2127 | if (!check_prevs_add(curr, hlock)) | |
2128 | return 0; | |
2129 | graph_unlock(); | |
2130 | } else | |
2131 | /* after lookup_chain_cache(): */ | |
2132 | if (unlikely(!debug_locks)) | |
2133 | return 0; | |
fbb9ce95 IM |
2134 | |
2135 | return 1; | |
2136 | } | |
8e18257d PZ |
2137 | #else |
2138 | static inline int validate_chain(struct task_struct *curr, | |
2139 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2140 | int chain_head, u64 chain_key) |
8e18257d PZ |
2141 | { |
2142 | return 1; | |
2143 | } | |
ca58abcb | 2144 | #endif |
fbb9ce95 IM |
2145 | |
2146 | /* | |
2147 | * We are building curr_chain_key incrementally, so double-check | |
2148 | * it from scratch, to make sure that it's done correctly: | |
2149 | */ | |
1d09daa5 | 2150 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2151 | { |
2152 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2153 | struct held_lock *hlock, *prev_hlock = NULL; | |
2154 | unsigned int i, id; | |
2155 | u64 chain_key = 0; | |
2156 | ||
2157 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2158 | hlock = curr->held_locks + i; | |
2159 | if (chain_key != hlock->prev_chain_key) { | |
2160 | debug_locks_off(); | |
0119fee4 PZ |
2161 | /* |
2162 | * We got mighty confused, our chain keys don't match | |
2163 | * with what we expect, someone trample on our task state? | |
2164 | */ | |
2df8b1d6 | 2165 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2166 | curr->lockdep_depth, i, |
2167 | (unsigned long long)chain_key, | |
2168 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2169 | return; |
2170 | } | |
f82b217e | 2171 | id = hlock->class_idx - 1; |
0119fee4 PZ |
2172 | /* |
2173 | * Whoops ran out of static storage again? | |
2174 | */ | |
381a2292 JP |
2175 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
2176 | return; | |
2177 | ||
fbb9ce95 IM |
2178 | if (prev_hlock && (prev_hlock->irq_context != |
2179 | hlock->irq_context)) | |
2180 | chain_key = 0; | |
2181 | chain_key = iterate_chain_key(chain_key, id); | |
2182 | prev_hlock = hlock; | |
2183 | } | |
2184 | if (chain_key != curr->curr_chain_key) { | |
2185 | debug_locks_off(); | |
0119fee4 PZ |
2186 | /* |
2187 | * More smoking hash instead of calculating it, damn see these | |
2188 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2189 | */ | |
2df8b1d6 | 2190 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2191 | curr->lockdep_depth, i, |
2192 | (unsigned long long)chain_key, | |
2193 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2194 | } |
2195 | #endif | |
2196 | } | |
2197 | ||
282b5c2f SR |
2198 | static void |
2199 | print_usage_bug_scenario(struct held_lock *lock) | |
2200 | { | |
2201 | struct lock_class *class = hlock_class(lock); | |
2202 | ||
2203 | printk(" Possible unsafe locking scenario:\n\n"); | |
2204 | printk(" CPU0\n"); | |
2205 | printk(" ----\n"); | |
2206 | printk(" lock("); | |
2207 | __print_lock_name(class); | |
2208 | printk(");\n"); | |
2209 | printk(" <Interrupt>\n"); | |
2210 | printk(" lock("); | |
2211 | __print_lock_name(class); | |
2212 | printk(");\n"); | |
2213 | printk("\n *** DEADLOCK ***\n\n"); | |
2214 | } | |
2215 | ||
8e18257d PZ |
2216 | static int |
2217 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2218 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2219 | { | |
2220 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2221 | return 0; | |
2222 | ||
b3fbab05 PM |
2223 | printk("\n"); |
2224 | printk("=================================\n"); | |
2225 | printk("[ INFO: inconsistent lock state ]\n"); | |
8e18257d | 2226 | print_kernel_version(); |
b3fbab05 | 2227 | printk("---------------------------------\n"); |
8e18257d PZ |
2228 | |
2229 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2230 | usage_str[prev_bit], usage_str[new_bit]); | |
2231 | ||
2232 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2233 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2234 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2235 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2236 | trace_hardirqs_enabled(curr), | |
2237 | trace_softirqs_enabled(curr)); | |
2238 | print_lock(this); | |
2239 | ||
2240 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2241 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2242 | |
2243 | print_irqtrace_events(curr); | |
2244 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2245 | print_usage_bug_scenario(this); |
2246 | ||
8e18257d PZ |
2247 | lockdep_print_held_locks(curr); |
2248 | ||
2249 | printk("\nstack backtrace:\n"); | |
2250 | dump_stack(); | |
2251 | ||
2252 | return 0; | |
2253 | } | |
2254 | ||
2255 | /* | |
2256 | * Print out an error if an invalid bit is set: | |
2257 | */ | |
2258 | static inline int | |
2259 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2260 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2261 | { | |
f82b217e | 2262 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2263 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2264 | return 1; | |
2265 | } | |
2266 | ||
2267 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2268 | enum lock_usage_bit new_bit); | |
2269 | ||
81d68a96 | 2270 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2271 | |
2272 | /* | |
2273 | * print irq inversion bug: | |
2274 | */ | |
2275 | static int | |
24208ca7 ML |
2276 | print_irq_inversion_bug(struct task_struct *curr, |
2277 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2278 | struct held_lock *this, int forwards, |
2279 | const char *irqclass) | |
2280 | { | |
dad3d743 SR |
2281 | struct lock_list *entry = other; |
2282 | struct lock_list *middle = NULL; | |
2283 | int depth; | |
2284 | ||
74c383f1 | 2285 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2286 | return 0; |
2287 | ||
b3fbab05 PM |
2288 | printk("\n"); |
2289 | printk("=========================================================\n"); | |
2290 | printk("[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2291 | print_kernel_version(); |
b3fbab05 | 2292 | printk("---------------------------------------------------------\n"); |
fbb9ce95 | 2293 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2294 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2295 | print_lock(this); |
2296 | if (forwards) | |
26575e28 | 2297 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2298 | else |
26575e28 | 2299 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2300 | print_lock_name(other->class); |
fbb9ce95 IM |
2301 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2302 | ||
2303 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2304 | |
2305 | /* Find a middle lock (if one exists) */ | |
2306 | depth = get_lock_depth(other); | |
2307 | do { | |
2308 | if (depth == 0 && (entry != root)) { | |
2309 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2310 | break; | |
2311 | } | |
2312 | middle = entry; | |
2313 | entry = get_lock_parent(entry); | |
2314 | depth--; | |
2315 | } while (entry && entry != root && (depth >= 0)); | |
2316 | if (forwards) | |
2317 | print_irq_lock_scenario(root, other, | |
2318 | middle ? middle->class : root->class, other->class); | |
2319 | else | |
2320 | print_irq_lock_scenario(other, root, | |
2321 | middle ? middle->class : other->class, root->class); | |
2322 | ||
fbb9ce95 IM |
2323 | lockdep_print_held_locks(curr); |
2324 | ||
24208ca7 ML |
2325 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2326 | if (!save_trace(&root->trace)) | |
2327 | return 0; | |
2328 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2329 | |
2330 | printk("\nstack backtrace:\n"); | |
2331 | dump_stack(); | |
2332 | ||
2333 | return 0; | |
2334 | } | |
2335 | ||
2336 | /* | |
2337 | * Prove that in the forwards-direction subgraph starting at <this> | |
2338 | * there is no lock matching <mask>: | |
2339 | */ | |
2340 | static int | |
2341 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2342 | enum lock_usage_bit bit, const char *irqclass) | |
2343 | { | |
2344 | int ret; | |
d7aaba14 ML |
2345 | struct lock_list root; |
2346 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2347 | |
d7aaba14 ML |
2348 | root.parent = NULL; |
2349 | root.class = hlock_class(this); | |
2350 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2351 | if (ret < 0) |
2352 | return print_bfs_bug(ret); | |
2353 | if (ret == 1) | |
2354 | return ret; | |
fbb9ce95 | 2355 | |
24208ca7 | 2356 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2357 | this, 1, irqclass); |
fbb9ce95 IM |
2358 | } |
2359 | ||
2360 | /* | |
2361 | * Prove that in the backwards-direction subgraph starting at <this> | |
2362 | * there is no lock matching <mask>: | |
2363 | */ | |
2364 | static int | |
2365 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2366 | enum lock_usage_bit bit, const char *irqclass) | |
2367 | { | |
2368 | int ret; | |
d7aaba14 ML |
2369 | struct lock_list root; |
2370 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2371 | |
d7aaba14 ML |
2372 | root.parent = NULL; |
2373 | root.class = hlock_class(this); | |
2374 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2375 | if (ret < 0) |
2376 | return print_bfs_bug(ret); | |
2377 | if (ret == 1) | |
2378 | return ret; | |
fbb9ce95 | 2379 | |
24208ca7 | 2380 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2381 | this, 0, irqclass); |
fbb9ce95 IM |
2382 | } |
2383 | ||
3117df04 | 2384 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2385 | { |
2386 | printk("irq event stamp: %u\n", curr->irq_events); | |
2387 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2388 | print_ip_sym(curr->hardirq_enable_ip); | |
2389 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2390 | print_ip_sym(curr->hardirq_disable_ip); | |
2391 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2392 | print_ip_sym(curr->softirq_enable_ip); | |
2393 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2394 | print_ip_sym(curr->softirq_disable_ip); | |
2395 | } | |
2396 | ||
cd95302d | 2397 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2398 | { |
8e18257d PZ |
2399 | #if HARDIRQ_VERBOSE |
2400 | return class_filter(class); | |
2401 | #endif | |
fbb9ce95 IM |
2402 | return 0; |
2403 | } | |
2404 | ||
cd95302d | 2405 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2406 | { |
8e18257d PZ |
2407 | #if SOFTIRQ_VERBOSE |
2408 | return class_filter(class); | |
2409 | #endif | |
2410 | return 0; | |
fbb9ce95 IM |
2411 | } |
2412 | ||
cd95302d | 2413 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2414 | { |
2415 | #if RECLAIM_VERBOSE | |
2416 | return class_filter(class); | |
2417 | #endif | |
2418 | return 0; | |
2419 | } | |
2420 | ||
fbb9ce95 IM |
2421 | #define STRICT_READ_CHECKS 1 |
2422 | ||
cd95302d PZ |
2423 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2424 | #define LOCKDEP_STATE(__STATE) \ | |
2425 | __STATE##_verbose, | |
2426 | #include "lockdep_states.h" | |
2427 | #undef LOCKDEP_STATE | |
2428 | }; | |
2429 | ||
2430 | static inline int state_verbose(enum lock_usage_bit bit, | |
2431 | struct lock_class *class) | |
2432 | { | |
2433 | return state_verbose_f[bit >> 2](class); | |
2434 | } | |
2435 | ||
42c50d54 PZ |
2436 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2437 | enum lock_usage_bit bit, const char *name); | |
2438 | ||
6a6904d3 | 2439 | static int |
1c21f14e PZ |
2440 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2441 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2442 | { |
f989209e | 2443 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2444 | int read = new_bit & 1; |
42c50d54 PZ |
2445 | int dir = new_bit & 2; |
2446 | ||
38aa2714 PZ |
2447 | /* |
2448 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2449 | * has ENABLED state, which would allow recursion deadlocks. | |
2450 | * | |
2451 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2452 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2453 | */ | |
42c50d54 PZ |
2454 | check_usage_f usage = dir ? |
2455 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2456 | |
38aa2714 PZ |
2457 | /* |
2458 | * Validate that this particular lock does not have conflicting | |
2459 | * usage states. | |
2460 | */ | |
6a6904d3 PZ |
2461 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2462 | return 0; | |
42c50d54 | 2463 | |
38aa2714 PZ |
2464 | /* |
2465 | * Validate that the lock dependencies don't have conflicting usage | |
2466 | * states. | |
2467 | */ | |
2468 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2469 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2470 | return 0; |
780e820b | 2471 | |
38aa2714 PZ |
2472 | /* |
2473 | * Check for read in write conflicts | |
2474 | */ | |
2475 | if (!read) { | |
2476 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2477 | return 0; | |
2478 | ||
2479 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2480 | !usage(curr, this, excl_bit + 1, |
2481 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2482 | return 0; |
2483 | } | |
780e820b | 2484 | |
cd95302d | 2485 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2486 | return 2; |
2487 | ||
2488 | return 1; | |
2489 | } | |
2490 | ||
cf40bd16 | 2491 | enum mark_type { |
36bfb9bb PZ |
2492 | #define LOCKDEP_STATE(__STATE) __STATE, |
2493 | #include "lockdep_states.h" | |
2494 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2495 | }; |
2496 | ||
fbb9ce95 IM |
2497 | /* |
2498 | * Mark all held locks with a usage bit: | |
2499 | */ | |
1d09daa5 | 2500 | static int |
cf40bd16 | 2501 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2502 | { |
2503 | enum lock_usage_bit usage_bit; | |
2504 | struct held_lock *hlock; | |
2505 | int i; | |
2506 | ||
2507 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2508 | hlock = curr->held_locks + i; | |
2509 | ||
cf2ad4d1 PZ |
2510 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2511 | if (hlock->read) | |
2512 | usage_bit += 1; /* READ */ | |
2513 | ||
2514 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2515 | |
70a0686a | 2516 | if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys) |
efbe2eee PZ |
2517 | continue; |
2518 | ||
4ff773bb | 2519 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2520 | return 0; |
2521 | } | |
2522 | ||
2523 | return 1; | |
2524 | } | |
2525 | ||
fbb9ce95 IM |
2526 | /* |
2527 | * Hardirqs will be enabled: | |
2528 | */ | |
dd4e5d3a | 2529 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2530 | { |
2531 | struct task_struct *curr = current; | |
fbb9ce95 | 2532 | |
fbb9ce95 IM |
2533 | /* we'll do an OFF -> ON transition: */ |
2534 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2535 | |
fbb9ce95 IM |
2536 | /* |
2537 | * We are going to turn hardirqs on, so set the | |
2538 | * usage bit for all held locks: | |
2539 | */ | |
cf40bd16 | 2540 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2541 | return; |
2542 | /* | |
2543 | * If we have softirqs enabled, then set the usage | |
2544 | * bit for all held locks. (disabled hardirqs prevented | |
2545 | * this bit from being set before) | |
2546 | */ | |
2547 | if (curr->softirqs_enabled) | |
cf40bd16 | 2548 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2549 | return; |
2550 | ||
8e18257d PZ |
2551 | curr->hardirq_enable_ip = ip; |
2552 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2553 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2554 | } |
dd4e5d3a PZ |
2555 | |
2556 | void trace_hardirqs_on_caller(unsigned long ip) | |
2557 | { | |
2558 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2559 | ||
2560 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2561 | return; | |
2562 | ||
7d36b26b PZ |
2563 | if (unlikely(current->hardirqs_enabled)) { |
2564 | /* | |
2565 | * Neither irq nor preemption are disabled here | |
2566 | * so this is racy by nature but losing one hit | |
2567 | * in a stat is not a big deal. | |
2568 | */ | |
2569 | __debug_atomic_inc(redundant_hardirqs_on); | |
2570 | return; | |
2571 | } | |
2572 | ||
0119fee4 PZ |
2573 | /* |
2574 | * We're enabling irqs and according to our state above irqs weren't | |
2575 | * already enabled, yet we find the hardware thinks they are in fact | |
2576 | * enabled.. someone messed up their IRQ state tracing. | |
2577 | */ | |
dd4e5d3a PZ |
2578 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2579 | return; | |
2580 | ||
0119fee4 PZ |
2581 | /* |
2582 | * See the fine text that goes along with this variable definition. | |
2583 | */ | |
7d36b26b PZ |
2584 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2585 | return; | |
2586 | ||
0119fee4 PZ |
2587 | /* |
2588 | * Can't allow enabling interrupts while in an interrupt handler, | |
2589 | * that's general bad form and such. Recursion, limited stack etc.. | |
2590 | */ | |
7d36b26b PZ |
2591 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2592 | return; | |
2593 | ||
dd4e5d3a PZ |
2594 | current->lockdep_recursion = 1; |
2595 | __trace_hardirqs_on_caller(ip); | |
2596 | current->lockdep_recursion = 0; | |
2597 | } | |
81d68a96 | 2598 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2599 | |
1d09daa5 | 2600 | void trace_hardirqs_on(void) |
81d68a96 SR |
2601 | { |
2602 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2603 | } | |
8e18257d PZ |
2604 | EXPORT_SYMBOL(trace_hardirqs_on); |
2605 | ||
2606 | /* | |
2607 | * Hardirqs were disabled: | |
2608 | */ | |
6afe40b4 | 2609 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2610 | { |
2611 | struct task_struct *curr = current; | |
2612 | ||
6afe40b4 | 2613 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2614 | |
8e18257d PZ |
2615 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2616 | return; | |
2617 | ||
0119fee4 PZ |
2618 | /* |
2619 | * So we're supposed to get called after you mask local IRQs, but for | |
2620 | * some reason the hardware doesn't quite think you did a proper job. | |
2621 | */ | |
8e18257d PZ |
2622 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2623 | return; | |
2624 | ||
2625 | if (curr->hardirqs_enabled) { | |
2626 | /* | |
2627 | * We have done an ON -> OFF transition: | |
2628 | */ | |
2629 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2630 | curr->hardirq_disable_ip = ip; |
8e18257d | 2631 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2632 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2633 | } else |
bd6d29c2 | 2634 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2635 | } |
81d68a96 | 2636 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2637 | |
1d09daa5 | 2638 | void trace_hardirqs_off(void) |
81d68a96 SR |
2639 | { |
2640 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2641 | } | |
8e18257d PZ |
2642 | EXPORT_SYMBOL(trace_hardirqs_off); |
2643 | ||
2644 | /* | |
2645 | * Softirqs will be enabled: | |
2646 | */ | |
2647 | void trace_softirqs_on(unsigned long ip) | |
2648 | { | |
2649 | struct task_struct *curr = current; | |
2650 | ||
dd4e5d3a | 2651 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2652 | return; |
2653 | ||
0119fee4 PZ |
2654 | /* |
2655 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2656 | * funny state and nesting things. | |
2657 | */ | |
8e18257d PZ |
2658 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2659 | return; | |
2660 | ||
2661 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2662 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2663 | return; |
2664 | } | |
2665 | ||
dd4e5d3a | 2666 | current->lockdep_recursion = 1; |
8e18257d PZ |
2667 | /* |
2668 | * We'll do an OFF -> ON transition: | |
2669 | */ | |
2670 | curr->softirqs_enabled = 1; | |
2671 | curr->softirq_enable_ip = ip; | |
2672 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2673 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2674 | /* |
2675 | * We are going to turn softirqs on, so set the | |
2676 | * usage bit for all held locks, if hardirqs are | |
2677 | * enabled too: | |
2678 | */ | |
2679 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2680 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2681 | current->lockdep_recursion = 0; |
8e18257d PZ |
2682 | } |
2683 | ||
2684 | /* | |
2685 | * Softirqs were disabled: | |
2686 | */ | |
2687 | void trace_softirqs_off(unsigned long ip) | |
2688 | { | |
2689 | struct task_struct *curr = current; | |
2690 | ||
dd4e5d3a | 2691 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2692 | return; |
2693 | ||
0119fee4 PZ |
2694 | /* |
2695 | * We fancy IRQs being disabled here, see softirq.c | |
2696 | */ | |
8e18257d PZ |
2697 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2698 | return; | |
2699 | ||
2700 | if (curr->softirqs_enabled) { | |
2701 | /* | |
2702 | * We have done an ON -> OFF transition: | |
2703 | */ | |
2704 | curr->softirqs_enabled = 0; | |
2705 | curr->softirq_disable_ip = ip; | |
2706 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2707 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
2708 | /* |
2709 | * Whoops, we wanted softirqs off, so why aren't they? | |
2710 | */ | |
8e18257d PZ |
2711 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2712 | } else | |
bd6d29c2 | 2713 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2714 | } |
2715 | ||
2f850181 | 2716 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2717 | { |
2718 | struct task_struct *curr = current; | |
2719 | ||
2720 | if (unlikely(!debug_locks)) | |
2721 | return; | |
2722 | ||
2723 | /* no reclaim without waiting on it */ | |
2724 | if (!(gfp_mask & __GFP_WAIT)) | |
2725 | return; | |
2726 | ||
2727 | /* this guy won't enter reclaim */ | |
2728 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2729 | return; | |
2730 | ||
2731 | /* We're only interested __GFP_FS allocations for now */ | |
2732 | if (!(gfp_mask & __GFP_FS)) | |
2733 | return; | |
2734 | ||
0119fee4 PZ |
2735 | /* |
2736 | * Oi! Can't be having __GFP_FS allocations with IRQs disabled. | |
2737 | */ | |
2f850181 | 2738 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2739 | return; |
2740 | ||
2741 | mark_held_locks(curr, RECLAIM_FS); | |
2742 | } | |
2743 | ||
2f850181 PZ |
2744 | static void check_flags(unsigned long flags); |
2745 | ||
2746 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2747 | { | |
2748 | unsigned long flags; | |
2749 | ||
2750 | if (unlikely(current->lockdep_recursion)) | |
2751 | return; | |
2752 | ||
2753 | raw_local_irq_save(flags); | |
2754 | check_flags(flags); | |
2755 | current->lockdep_recursion = 1; | |
2756 | __lockdep_trace_alloc(gfp_mask, flags); | |
2757 | current->lockdep_recursion = 0; | |
2758 | raw_local_irq_restore(flags); | |
2759 | } | |
2760 | ||
8e18257d PZ |
2761 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2762 | { | |
2763 | /* | |
2764 | * If non-trylock use in a hardirq or softirq context, then | |
2765 | * mark the lock as used in these contexts: | |
2766 | */ | |
2767 | if (!hlock->trylock) { | |
2768 | if (hlock->read) { | |
2769 | if (curr->hardirq_context) | |
2770 | if (!mark_lock(curr, hlock, | |
2771 | LOCK_USED_IN_HARDIRQ_READ)) | |
2772 | return 0; | |
2773 | if (curr->softirq_context) | |
2774 | if (!mark_lock(curr, hlock, | |
2775 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2776 | return 0; | |
2777 | } else { | |
2778 | if (curr->hardirq_context) | |
2779 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2780 | return 0; | |
2781 | if (curr->softirq_context) | |
2782 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2783 | return 0; | |
2784 | } | |
2785 | } | |
2786 | if (!hlock->hardirqs_off) { | |
2787 | if (hlock->read) { | |
2788 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2789 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2790 | return 0; |
2791 | if (curr->softirqs_enabled) | |
2792 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2793 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2794 | return 0; |
2795 | } else { | |
2796 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2797 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2798 | return 0; |
2799 | if (curr->softirqs_enabled) | |
2800 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2801 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2802 | return 0; |
2803 | } | |
2804 | } | |
2805 | ||
cf40bd16 NP |
2806 | /* |
2807 | * We reuse the irq context infrastructure more broadly as a general | |
2808 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2809 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2810 | * allocation). | |
2811 | */ | |
2812 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2813 | if (hlock->read) { | |
2814 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2815 | return 0; | |
2816 | } else { | |
2817 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2818 | return 0; | |
2819 | } | |
2820 | } | |
2821 | ||
8e18257d PZ |
2822 | return 1; |
2823 | } | |
2824 | ||
2825 | static int separate_irq_context(struct task_struct *curr, | |
2826 | struct held_lock *hlock) | |
2827 | { | |
2828 | unsigned int depth = curr->lockdep_depth; | |
2829 | ||
2830 | /* | |
2831 | * Keep track of points where we cross into an interrupt context: | |
2832 | */ | |
2833 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2834 | curr->softirq_context; | |
2835 | if (depth) { | |
2836 | struct held_lock *prev_hlock; | |
2837 | ||
2838 | prev_hlock = curr->held_locks + depth-1; | |
2839 | /* | |
2840 | * If we cross into another context, reset the | |
2841 | * hash key (this also prevents the checking and the | |
2842 | * adding of the dependency to 'prev'): | |
2843 | */ | |
2844 | if (prev_hlock->irq_context != hlock->irq_context) | |
2845 | return 1; | |
2846 | } | |
2847 | return 0; | |
fbb9ce95 IM |
2848 | } |
2849 | ||
0119fee4 | 2850 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 2851 | |
8e18257d PZ |
2852 | static inline |
2853 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2854 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2855 | { |
0119fee4 | 2856 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
2857 | return 1; |
2858 | } | |
fbb9ce95 | 2859 | |
8e18257d PZ |
2860 | static inline int mark_irqflags(struct task_struct *curr, |
2861 | struct held_lock *hlock) | |
2862 | { | |
2863 | return 1; | |
2864 | } | |
fbb9ce95 | 2865 | |
8e18257d PZ |
2866 | static inline int separate_irq_context(struct task_struct *curr, |
2867 | struct held_lock *hlock) | |
2868 | { | |
2869 | return 0; | |
fbb9ce95 IM |
2870 | } |
2871 | ||
868a23a8 PZ |
2872 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2873 | { | |
2874 | } | |
2875 | ||
0119fee4 | 2876 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
2877 | |
2878 | /* | |
8e18257d | 2879 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2880 | */ |
1d09daa5 | 2881 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2882 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2883 | { |
8e18257d | 2884 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2885 | |
2886 | /* | |
8e18257d PZ |
2887 | * If already set then do not dirty the cacheline, |
2888 | * nor do any checks: | |
fbb9ce95 | 2889 | */ |
f82b217e | 2890 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2891 | return 1; |
2892 | ||
2893 | if (!graph_lock()) | |
2894 | return 0; | |
fbb9ce95 | 2895 | /* |
25985edc | 2896 | * Make sure we didn't race: |
fbb9ce95 | 2897 | */ |
f82b217e | 2898 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2899 | graph_unlock(); |
2900 | return 1; | |
2901 | } | |
fbb9ce95 | 2902 | |
f82b217e | 2903 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2904 | |
f82b217e | 2905 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2906 | return 0; |
fbb9ce95 | 2907 | |
8e18257d | 2908 | switch (new_bit) { |
5346417e PZ |
2909 | #define LOCKDEP_STATE(__STATE) \ |
2910 | case LOCK_USED_IN_##__STATE: \ | |
2911 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2912 | case LOCK_ENABLED_##__STATE: \ | |
2913 | case LOCK_ENABLED_##__STATE##_READ: | |
2914 | #include "lockdep_states.h" | |
2915 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2916 | ret = mark_lock_irq(curr, this, new_bit); |
2917 | if (!ret) | |
2918 | return 0; | |
2919 | break; | |
2920 | case LOCK_USED: | |
bd6d29c2 | 2921 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
2922 | break; |
2923 | default: | |
2924 | if (!debug_locks_off_graph_unlock()) | |
2925 | return 0; | |
2926 | WARN_ON(1); | |
2927 | return 0; | |
2928 | } | |
fbb9ce95 | 2929 | |
8e18257d PZ |
2930 | graph_unlock(); |
2931 | ||
2932 | /* | |
2933 | * We must printk outside of the graph_lock: | |
2934 | */ | |
2935 | if (ret == 2) { | |
2936 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2937 | print_lock(this); | |
2938 | print_irqtrace_events(curr); | |
2939 | dump_stack(); | |
2940 | } | |
2941 | ||
2942 | return ret; | |
2943 | } | |
fbb9ce95 IM |
2944 | |
2945 | /* | |
2946 | * Initialize a lock instance's lock-class mapping info: | |
2947 | */ | |
2948 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2949 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2950 | { |
f59de899 | 2951 | memset(lock, 0, sizeof(*lock)); |
62016250 | 2952 | |
c8a25005 PZ |
2953 | #ifdef CONFIG_LOCK_STAT |
2954 | lock->cpu = raw_smp_processor_id(); | |
2955 | #endif | |
2956 | ||
0119fee4 PZ |
2957 | /* |
2958 | * Can't be having no nameless bastards around this place! | |
2959 | */ | |
c8a25005 PZ |
2960 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
2961 | lock->name = "NULL"; | |
fbb9ce95 | 2962 | return; |
c8a25005 PZ |
2963 | } |
2964 | ||
2965 | lock->name = name; | |
fbb9ce95 | 2966 | |
0119fee4 PZ |
2967 | /* |
2968 | * No key, no joy, we need to hash something. | |
2969 | */ | |
fbb9ce95 IM |
2970 | if (DEBUG_LOCKS_WARN_ON(!key)) |
2971 | return; | |
fbb9ce95 IM |
2972 | /* |
2973 | * Sanity check, the lock-class key must be persistent: | |
2974 | */ | |
2975 | if (!static_obj(key)) { | |
2976 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
2977 | /* |
2978 | * What it says above ^^^^^, I suggest you read it. | |
2979 | */ | |
fbb9ce95 IM |
2980 | DEBUG_LOCKS_WARN_ON(1); |
2981 | return; | |
2982 | } | |
fbb9ce95 | 2983 | lock->key = key; |
c8a25005 PZ |
2984 | |
2985 | if (unlikely(!debug_locks)) | |
2986 | return; | |
2987 | ||
4dfbb9d8 PZ |
2988 | if (subclass) |
2989 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2990 | } |
fbb9ce95 IM |
2991 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2992 | ||
1704f47b PZ |
2993 | struct lock_class_key __lockdep_no_validate__; |
2994 | ||
fbb9ce95 IM |
2995 | /* |
2996 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2997 | * We maintain the dependency maps and validate the locking attempt: | |
2998 | */ | |
2999 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3000 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
3001 | struct lockdep_map *nest_lock, unsigned long ip, |
3002 | int references) | |
fbb9ce95 IM |
3003 | { |
3004 | struct task_struct *curr = current; | |
d6d897ce | 3005 | struct lock_class *class = NULL; |
fbb9ce95 | 3006 | struct held_lock *hlock; |
fbb9ce95 IM |
3007 | unsigned int depth, id; |
3008 | int chain_head = 0; | |
bb97a91e | 3009 | int class_idx; |
fbb9ce95 IM |
3010 | u64 chain_key; |
3011 | ||
f20786ff PZ |
3012 | if (!prove_locking) |
3013 | check = 1; | |
3014 | ||
fbb9ce95 IM |
3015 | if (unlikely(!debug_locks)) |
3016 | return 0; | |
3017 | ||
0119fee4 PZ |
3018 | /* |
3019 | * Lockdep should run with IRQs disabled, otherwise we could | |
3020 | * get an interrupt which would want to take locks, which would | |
3021 | * end up in lockdep and have you got a head-ache already? | |
3022 | */ | |
fbb9ce95 IM |
3023 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3024 | return 0; | |
3025 | ||
1704f47b PZ |
3026 | if (lock->key == &__lockdep_no_validate__) |
3027 | check = 1; | |
3028 | ||
62016250 HM |
3029 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3030 | class = lock->class_cache[subclass]; | |
d6d897ce | 3031 | /* |
62016250 | 3032 | * Not cached? |
d6d897ce | 3033 | */ |
fbb9ce95 | 3034 | if (unlikely(!class)) { |
4dfbb9d8 | 3035 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3036 | if (!class) |
3037 | return 0; | |
3038 | } | |
bd6d29c2 | 3039 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3040 | if (very_verbose(class)) { |
3041 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3042 | if (class->name_version > 1) | |
3043 | printk("#%d", class->name_version); | |
3044 | printk("\n"); | |
3045 | dump_stack(); | |
3046 | } | |
3047 | ||
3048 | /* | |
3049 | * Add the lock to the list of currently held locks. | |
3050 | * (we dont increase the depth just yet, up until the | |
3051 | * dependency checks are done) | |
3052 | */ | |
3053 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3054 | /* |
3055 | * Ran out of static storage for our per-task lock stack again have we? | |
3056 | */ | |
fbb9ce95 IM |
3057 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3058 | return 0; | |
3059 | ||
bb97a91e PZ |
3060 | class_idx = class - lock_classes + 1; |
3061 | ||
3062 | if (depth) { | |
3063 | hlock = curr->held_locks + depth - 1; | |
3064 | if (hlock->class_idx == class_idx && nest_lock) { | |
3065 | if (hlock->references) | |
3066 | hlock->references++; | |
3067 | else | |
3068 | hlock->references = 2; | |
3069 | ||
3070 | return 1; | |
3071 | } | |
3072 | } | |
3073 | ||
fbb9ce95 | 3074 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3075 | /* |
3076 | * Plain impossible, we just registered it and checked it weren't no | |
3077 | * NULL like.. I bet this mushroom I ate was good! | |
3078 | */ | |
f82b217e DJ |
3079 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3080 | return 0; | |
bb97a91e | 3081 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3082 | hlock->acquire_ip = ip; |
3083 | hlock->instance = lock; | |
7531e2f3 | 3084 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
3085 | hlock->trylock = trylock; |
3086 | hlock->read = read; | |
3087 | hlock->check = check; | |
6951b12a | 3088 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3089 | hlock->references = references; |
f20786ff PZ |
3090 | #ifdef CONFIG_LOCK_STAT |
3091 | hlock->waittime_stamp = 0; | |
3365e779 | 3092 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3093 | #endif |
fbb9ce95 | 3094 | |
8e18257d PZ |
3095 | if (check == 2 && !mark_irqflags(curr, hlock)) |
3096 | return 0; | |
3097 | ||
fbb9ce95 | 3098 | /* mark it as used: */ |
4ff773bb | 3099 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3100 | return 0; |
8e18257d | 3101 | |
fbb9ce95 | 3102 | /* |
17aacfb9 | 3103 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3104 | * lock keys along the dependency chain. We save the hash value |
3105 | * at every step so that we can get the current hash easily | |
3106 | * after unlock. The chain hash is then used to cache dependency | |
3107 | * results. | |
3108 | * | |
3109 | * The 'key ID' is what is the most compact key value to drive | |
3110 | * the hash, not class->key. | |
3111 | */ | |
3112 | id = class - lock_classes; | |
0119fee4 PZ |
3113 | /* |
3114 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3115 | */ | |
fbb9ce95 IM |
3116 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
3117 | return 0; | |
3118 | ||
3119 | chain_key = curr->curr_chain_key; | |
3120 | if (!depth) { | |
0119fee4 PZ |
3121 | /* |
3122 | * How can we have a chain hash when we ain't got no keys?! | |
3123 | */ | |
fbb9ce95 IM |
3124 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3125 | return 0; | |
3126 | chain_head = 1; | |
3127 | } | |
3128 | ||
3129 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3130 | if (separate_irq_context(curr, hlock)) { |
3131 | chain_key = 0; | |
3132 | chain_head = 1; | |
fbb9ce95 | 3133 | } |
fbb9ce95 | 3134 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 3135 | |
3aa416b0 | 3136 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3137 | return 0; |
381a2292 | 3138 | |
3aa416b0 | 3139 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3140 | curr->lockdep_depth++; |
3141 | check_chain_key(curr); | |
60e114d1 JP |
3142 | #ifdef CONFIG_DEBUG_LOCKDEP |
3143 | if (unlikely(!debug_locks)) | |
3144 | return 0; | |
3145 | #endif | |
fbb9ce95 IM |
3146 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3147 | debug_locks_off(); | |
3148 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
3149 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 3150 | dump_stack(); |
fbb9ce95 IM |
3151 | return 0; |
3152 | } | |
381a2292 | 3153 | |
fbb9ce95 IM |
3154 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3155 | max_lockdep_depth = curr->lockdep_depth; | |
3156 | ||
3157 | return 1; | |
3158 | } | |
3159 | ||
3160 | static int | |
3161 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3162 | unsigned long ip) | |
3163 | { | |
3164 | if (!debug_locks_off()) | |
3165 | return 0; | |
3166 | if (debug_locks_silent) | |
3167 | return 0; | |
3168 | ||
b3fbab05 PM |
3169 | printk("\n"); |
3170 | printk("=====================================\n"); | |
3171 | printk("[ BUG: bad unlock balance detected! ]\n"); | |
3172 | printk("-------------------------------------\n"); | |
fbb9ce95 | 3173 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3174 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3175 | print_lockdep_cache(lock); |
3176 | printk(") at:\n"); | |
3177 | print_ip_sym(ip); | |
3178 | printk("but there are no more locks to release!\n"); | |
3179 | printk("\nother info that might help us debug this:\n"); | |
3180 | lockdep_print_held_locks(curr); | |
3181 | ||
3182 | printk("\nstack backtrace:\n"); | |
3183 | dump_stack(); | |
3184 | ||
3185 | return 0; | |
3186 | } | |
3187 | ||
3188 | /* | |
3189 | * Common debugging checks for both nested and non-nested unlock: | |
3190 | */ | |
3191 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
3192 | unsigned long ip) | |
3193 | { | |
3194 | if (unlikely(!debug_locks)) | |
3195 | return 0; | |
0119fee4 PZ |
3196 | /* |
3197 | * Lockdep should run with IRQs disabled, recursion, head-ache, etc.. | |
3198 | */ | |
fbb9ce95 IM |
3199 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3200 | return 0; | |
3201 | ||
3202 | if (curr->lockdep_depth <= 0) | |
3203 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3204 | ||
3205 | return 1; | |
3206 | } | |
3207 | ||
bb97a91e PZ |
3208 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3209 | { | |
3210 | if (hlock->instance == lock) | |
3211 | return 1; | |
3212 | ||
3213 | if (hlock->references) { | |
62016250 | 3214 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3215 | |
3216 | if (!class) | |
3217 | class = look_up_lock_class(lock, 0); | |
3218 | ||
80e0401e PZ |
3219 | /* |
3220 | * If look_up_lock_class() failed to find a class, we're trying | |
3221 | * to test if we hold a lock that has never yet been acquired. | |
3222 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3223 | * holding it either, so report failure. | |
3224 | */ | |
3225 | if (!class) | |
bb97a91e PZ |
3226 | return 0; |
3227 | ||
0119fee4 PZ |
3228 | /* |
3229 | * References, but not a lock we're actually ref-counting? | |
3230 | * State got messed up, follow the sites that change ->references | |
3231 | * and try to make sense of it. | |
3232 | */ | |
bb97a91e PZ |
3233 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3234 | return 0; | |
3235 | ||
3236 | if (hlock->class_idx == class - lock_classes + 1) | |
3237 | return 1; | |
3238 | } | |
3239 | ||
3240 | return 0; | |
3241 | } | |
3242 | ||
64aa348e | 3243 | static int |
00ef9f73 PZ |
3244 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3245 | struct lock_class_key *key, unsigned int subclass, | |
3246 | unsigned long ip) | |
64aa348e PZ |
3247 | { |
3248 | struct task_struct *curr = current; | |
3249 | struct held_lock *hlock, *prev_hlock; | |
3250 | struct lock_class *class; | |
3251 | unsigned int depth; | |
3252 | int i; | |
3253 | ||
3254 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3255 | /* |
3256 | * This function is about (re)setting the class of a held lock, | |
3257 | * yet we're not actually holding any locks. Naughty user! | |
3258 | */ | |
64aa348e PZ |
3259 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3260 | return 0; | |
3261 | ||
3262 | prev_hlock = NULL; | |
3263 | for (i = depth-1; i >= 0; i--) { | |
3264 | hlock = curr->held_locks + i; | |
3265 | /* | |
3266 | * We must not cross into another context: | |
3267 | */ | |
3268 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3269 | break; | |
bb97a91e | 3270 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3271 | goto found_it; |
3272 | prev_hlock = hlock; | |
3273 | } | |
3274 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3275 | ||
3276 | found_it: | |
00ef9f73 | 3277 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3278 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3279 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3280 | |
3281 | curr->lockdep_depth = i; | |
3282 | curr->curr_chain_key = hlock->prev_chain_key; | |
3283 | ||
3284 | for (; i < depth; i++) { | |
3285 | hlock = curr->held_locks + i; | |
3286 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3287 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3288 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3289 | hlock->nest_lock, hlock->acquire_ip, |
3290 | hlock->references)) | |
64aa348e PZ |
3291 | return 0; |
3292 | } | |
3293 | ||
0119fee4 PZ |
3294 | /* |
3295 | * I took it apart and put it back together again, except now I have | |
3296 | * these 'spare' parts.. where shall I put them. | |
3297 | */ | |
64aa348e PZ |
3298 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3299 | return 0; | |
3300 | return 1; | |
3301 | } | |
3302 | ||
fbb9ce95 IM |
3303 | /* |
3304 | * Remove the lock to the list of currently held locks in a | |
3305 | * potentially non-nested (out of order) manner. This is a | |
3306 | * relatively rare operation, as all the unlock APIs default | |
3307 | * to nested mode (which uses lock_release()): | |
3308 | */ | |
3309 | static int | |
3310 | lock_release_non_nested(struct task_struct *curr, | |
3311 | struct lockdep_map *lock, unsigned long ip) | |
3312 | { | |
3313 | struct held_lock *hlock, *prev_hlock; | |
3314 | unsigned int depth; | |
3315 | int i; | |
3316 | ||
3317 | /* | |
3318 | * Check whether the lock exists in the current stack | |
3319 | * of held locks: | |
3320 | */ | |
3321 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3322 | /* |
3323 | * So we're all set to release this lock.. wait what lock? We don't | |
3324 | * own any locks, you've been drinking again? | |
3325 | */ | |
fbb9ce95 IM |
3326 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3327 | return 0; | |
3328 | ||
3329 | prev_hlock = NULL; | |
3330 | for (i = depth-1; i >= 0; i--) { | |
3331 | hlock = curr->held_locks + i; | |
3332 | /* | |
3333 | * We must not cross into another context: | |
3334 | */ | |
3335 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3336 | break; | |
bb97a91e | 3337 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3338 | goto found_it; |
3339 | prev_hlock = hlock; | |
3340 | } | |
3341 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3342 | ||
3343 | found_it: | |
bb97a91e PZ |
3344 | if (hlock->instance == lock) |
3345 | lock_release_holdtime(hlock); | |
3346 | ||
3347 | if (hlock->references) { | |
3348 | hlock->references--; | |
3349 | if (hlock->references) { | |
3350 | /* | |
3351 | * We had, and after removing one, still have | |
3352 | * references, the current lock stack is still | |
3353 | * valid. We're done! | |
3354 | */ | |
3355 | return 1; | |
3356 | } | |
3357 | } | |
f20786ff | 3358 | |
fbb9ce95 IM |
3359 | /* |
3360 | * We have the right lock to unlock, 'hlock' points to it. | |
3361 | * Now we remove it from the stack, and add back the other | |
3362 | * entries (if any), recalculating the hash along the way: | |
3363 | */ | |
bb97a91e | 3364 | |
fbb9ce95 IM |
3365 | curr->lockdep_depth = i; |
3366 | curr->curr_chain_key = hlock->prev_chain_key; | |
3367 | ||
3368 | for (i++; i < depth; i++) { | |
3369 | hlock = curr->held_locks + i; | |
3370 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3371 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3372 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3373 | hlock->nest_lock, hlock->acquire_ip, |
3374 | hlock->references)) | |
fbb9ce95 IM |
3375 | return 0; |
3376 | } | |
3377 | ||
0119fee4 PZ |
3378 | /* |
3379 | * We had N bottles of beer on the wall, we drank one, but now | |
3380 | * there's not N-1 bottles of beer left on the wall... | |
3381 | */ | |
fbb9ce95 IM |
3382 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3383 | return 0; | |
3384 | return 1; | |
3385 | } | |
3386 | ||
3387 | /* | |
3388 | * Remove the lock to the list of currently held locks - this gets | |
3389 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3390 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3391 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3392 | */ | |
3393 | static int lock_release_nested(struct task_struct *curr, | |
3394 | struct lockdep_map *lock, unsigned long ip) | |
3395 | { | |
3396 | struct held_lock *hlock; | |
3397 | unsigned int depth; | |
3398 | ||
3399 | /* | |
3400 | * Pop off the top of the lock stack: | |
3401 | */ | |
3402 | depth = curr->lockdep_depth - 1; | |
3403 | hlock = curr->held_locks + depth; | |
3404 | ||
3405 | /* | |
3406 | * Is the unlock non-nested: | |
3407 | */ | |
bb97a91e | 3408 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3409 | return lock_release_non_nested(curr, lock, ip); |
3410 | curr->lockdep_depth--; | |
3411 | ||
0119fee4 PZ |
3412 | /* |
3413 | * No more locks, but somehow we've got hash left over, who left it? | |
3414 | */ | |
fbb9ce95 IM |
3415 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) |
3416 | return 0; | |
3417 | ||
3418 | curr->curr_chain_key = hlock->prev_chain_key; | |
3419 | ||
f20786ff PZ |
3420 | lock_release_holdtime(hlock); |
3421 | ||
fbb9ce95 IM |
3422 | #ifdef CONFIG_DEBUG_LOCKDEP |
3423 | hlock->prev_chain_key = 0; | |
f82b217e | 3424 | hlock->class_idx = 0; |
fbb9ce95 IM |
3425 | hlock->acquire_ip = 0; |
3426 | hlock->irq_context = 0; | |
3427 | #endif | |
3428 | return 1; | |
3429 | } | |
3430 | ||
3431 | /* | |
3432 | * Remove the lock to the list of currently held locks - this gets | |
3433 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3434 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3435 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3436 | */ | |
3437 | static void | |
3438 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3439 | { | |
3440 | struct task_struct *curr = current; | |
3441 | ||
3442 | if (!check_unlock(curr, lock, ip)) | |
3443 | return; | |
3444 | ||
3445 | if (nested) { | |
3446 | if (!lock_release_nested(curr, lock, ip)) | |
3447 | return; | |
3448 | } else { | |
3449 | if (!lock_release_non_nested(curr, lock, ip)) | |
3450 | return; | |
3451 | } | |
3452 | ||
3453 | check_chain_key(curr); | |
3454 | } | |
3455 | ||
f607c668 PZ |
3456 | static int __lock_is_held(struct lockdep_map *lock) |
3457 | { | |
3458 | struct task_struct *curr = current; | |
3459 | int i; | |
3460 | ||
3461 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3462 | struct held_lock *hlock = curr->held_locks + i; |
3463 | ||
3464 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3465 | return 1; |
3466 | } | |
3467 | ||
3468 | return 0; | |
3469 | } | |
3470 | ||
fbb9ce95 IM |
3471 | /* |
3472 | * Check whether we follow the irq-flags state precisely: | |
3473 | */ | |
1d09daa5 | 3474 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3475 | { |
992860e9 IM |
3476 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3477 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3478 | if (!debug_locks) |
3479 | return; | |
3480 | ||
5f9fa8a6 IM |
3481 | if (irqs_disabled_flags(flags)) { |
3482 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3483 | printk("possible reason: unannotated irqs-off.\n"); | |
3484 | } | |
3485 | } else { | |
3486 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3487 | printk("possible reason: unannotated irqs-on.\n"); | |
3488 | } | |
3489 | } | |
fbb9ce95 IM |
3490 | |
3491 | /* | |
3492 | * We dont accurately track softirq state in e.g. | |
3493 | * hardirq contexts (such as on 4KSTACKS), so only | |
3494 | * check if not in hardirq contexts: | |
3495 | */ | |
3496 | if (!hardirq_count()) { | |
0119fee4 PZ |
3497 | if (softirq_count()) { |
3498 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3499 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3500 | } else { |
3501 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3502 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3503 | } |
fbb9ce95 IM |
3504 | } |
3505 | ||
3506 | if (!debug_locks) | |
3507 | print_irqtrace_events(current); | |
3508 | #endif | |
3509 | } | |
3510 | ||
00ef9f73 PZ |
3511 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3512 | struct lock_class_key *key, unsigned int subclass, | |
3513 | unsigned long ip) | |
64aa348e PZ |
3514 | { |
3515 | unsigned long flags; | |
3516 | ||
3517 | if (unlikely(current->lockdep_recursion)) | |
3518 | return; | |
3519 | ||
3520 | raw_local_irq_save(flags); | |
3521 | current->lockdep_recursion = 1; | |
3522 | check_flags(flags); | |
00ef9f73 | 3523 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3524 | check_chain_key(current); |
3525 | current->lockdep_recursion = 0; | |
3526 | raw_local_irq_restore(flags); | |
3527 | } | |
00ef9f73 | 3528 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3529 | |
fbb9ce95 IM |
3530 | /* |
3531 | * We are not always called with irqs disabled - do that here, | |
3532 | * and also avoid lockdep recursion: | |
3533 | */ | |
1d09daa5 | 3534 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3535 | int trylock, int read, int check, |
3536 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3537 | { |
3538 | unsigned long flags; | |
3539 | ||
3540 | if (unlikely(current->lockdep_recursion)) | |
3541 | return; | |
3542 | ||
3543 | raw_local_irq_save(flags); | |
3544 | check_flags(flags); | |
3545 | ||
3546 | current->lockdep_recursion = 1; | |
db2c4c77 | 3547 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3548 | __lock_acquire(lock, subclass, trylock, read, check, |
bb97a91e | 3549 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3550 | current->lockdep_recursion = 0; |
3551 | raw_local_irq_restore(flags); | |
3552 | } | |
fbb9ce95 IM |
3553 | EXPORT_SYMBOL_GPL(lock_acquire); |
3554 | ||
1d09daa5 | 3555 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3556 | unsigned long ip) |
fbb9ce95 IM |
3557 | { |
3558 | unsigned long flags; | |
3559 | ||
3560 | if (unlikely(current->lockdep_recursion)) | |
3561 | return; | |
3562 | ||
3563 | raw_local_irq_save(flags); | |
3564 | check_flags(flags); | |
3565 | current->lockdep_recursion = 1; | |
93135439 | 3566 | trace_lock_release(lock, ip); |
fbb9ce95 IM |
3567 | __lock_release(lock, nested, ip); |
3568 | current->lockdep_recursion = 0; | |
3569 | raw_local_irq_restore(flags); | |
3570 | } | |
fbb9ce95 IM |
3571 | EXPORT_SYMBOL_GPL(lock_release); |
3572 | ||
f607c668 PZ |
3573 | int lock_is_held(struct lockdep_map *lock) |
3574 | { | |
3575 | unsigned long flags; | |
3576 | int ret = 0; | |
3577 | ||
3578 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3579 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3580 | |
3581 | raw_local_irq_save(flags); | |
3582 | check_flags(flags); | |
3583 | ||
3584 | current->lockdep_recursion = 1; | |
3585 | ret = __lock_is_held(lock); | |
3586 | current->lockdep_recursion = 0; | |
3587 | raw_local_irq_restore(flags); | |
3588 | ||
3589 | return ret; | |
3590 | } | |
3591 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3592 | ||
cf40bd16 NP |
3593 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3594 | { | |
3595 | current->lockdep_reclaim_gfp = gfp_mask; | |
3596 | } | |
3597 | ||
3598 | void lockdep_clear_current_reclaim_state(void) | |
3599 | { | |
3600 | current->lockdep_reclaim_gfp = 0; | |
3601 | } | |
3602 | ||
f20786ff PZ |
3603 | #ifdef CONFIG_LOCK_STAT |
3604 | static int | |
3605 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3606 | unsigned long ip) | |
3607 | { | |
3608 | if (!debug_locks_off()) | |
3609 | return 0; | |
3610 | if (debug_locks_silent) | |
3611 | return 0; | |
3612 | ||
b3fbab05 PM |
3613 | printk("\n"); |
3614 | printk("=================================\n"); | |
3615 | printk("[ BUG: bad contention detected! ]\n"); | |
3616 | printk("---------------------------------\n"); | |
f20786ff | 3617 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3618 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3619 | print_lockdep_cache(lock); |
3620 | printk(") at:\n"); | |
3621 | print_ip_sym(ip); | |
3622 | printk("but there are no locks held!\n"); | |
3623 | printk("\nother info that might help us debug this:\n"); | |
3624 | lockdep_print_held_locks(curr); | |
3625 | ||
3626 | printk("\nstack backtrace:\n"); | |
3627 | dump_stack(); | |
3628 | ||
3629 | return 0; | |
3630 | } | |
3631 | ||
3632 | static void | |
3633 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3634 | { | |
3635 | struct task_struct *curr = current; | |
3636 | struct held_lock *hlock, *prev_hlock; | |
3637 | struct lock_class_stats *stats; | |
3638 | unsigned int depth; | |
c7e78cff | 3639 | int i, contention_point, contending_point; |
f20786ff PZ |
3640 | |
3641 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3642 | /* |
3643 | * Whee, we contended on this lock, except it seems we're not | |
3644 | * actually trying to acquire anything much at all.. | |
3645 | */ | |
f20786ff PZ |
3646 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3647 | return; | |
3648 | ||
3649 | prev_hlock = NULL; | |
3650 | for (i = depth-1; i >= 0; i--) { | |
3651 | hlock = curr->held_locks + i; | |
3652 | /* | |
3653 | * We must not cross into another context: | |
3654 | */ | |
3655 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3656 | break; | |
bb97a91e | 3657 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3658 | goto found_it; |
3659 | prev_hlock = hlock; | |
3660 | } | |
3661 | print_lock_contention_bug(curr, lock, ip); | |
3662 | return; | |
3663 | ||
3664 | found_it: | |
bb97a91e PZ |
3665 | if (hlock->instance != lock) |
3666 | return; | |
3667 | ||
3365e779 | 3668 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3669 | |
c7e78cff PZ |
3670 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3671 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3672 | lock->ip); | |
f20786ff | 3673 | |
f82b217e | 3674 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3675 | if (contention_point < LOCKSTAT_POINTS) |
3676 | stats->contention_point[contention_point]++; | |
3677 | if (contending_point < LOCKSTAT_POINTS) | |
3678 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3679 | if (lock->cpu != smp_processor_id()) |
3680 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3681 | put_lock_stats(stats); |
3682 | } | |
3683 | ||
3684 | static void | |
c7e78cff | 3685 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3686 | { |
3687 | struct task_struct *curr = current; | |
3688 | struct held_lock *hlock, *prev_hlock; | |
3689 | struct lock_class_stats *stats; | |
3690 | unsigned int depth; | |
3365e779 | 3691 | u64 now, waittime = 0; |
96645678 | 3692 | int i, cpu; |
f20786ff PZ |
3693 | |
3694 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3695 | /* |
3696 | * Yay, we acquired ownership of this lock we didn't try to | |
3697 | * acquire, how the heck did that happen? | |
3698 | */ | |
f20786ff PZ |
3699 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3700 | return; | |
3701 | ||
3702 | prev_hlock = NULL; | |
3703 | for (i = depth-1; i >= 0; i--) { | |
3704 | hlock = curr->held_locks + i; | |
3705 | /* | |
3706 | * We must not cross into another context: | |
3707 | */ | |
3708 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3709 | break; | |
bb97a91e | 3710 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3711 | goto found_it; |
3712 | prev_hlock = hlock; | |
3713 | } | |
3714 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3715 | return; | |
3716 | ||
3717 | found_it: | |
bb97a91e PZ |
3718 | if (hlock->instance != lock) |
3719 | return; | |
3720 | ||
96645678 PZ |
3721 | cpu = smp_processor_id(); |
3722 | if (hlock->waittime_stamp) { | |
3365e779 | 3723 | now = lockstat_clock(); |
96645678 PZ |
3724 | waittime = now - hlock->waittime_stamp; |
3725 | hlock->holdtime_stamp = now; | |
3726 | } | |
f20786ff | 3727 | |
883a2a31 | 3728 | trace_lock_acquired(lock, ip); |
2062501a | 3729 | |
f82b217e | 3730 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3731 | if (waittime) { |
3732 | if (hlock->read) | |
3733 | lock_time_inc(&stats->read_waittime, waittime); | |
3734 | else | |
3735 | lock_time_inc(&stats->write_waittime, waittime); | |
3736 | } | |
3737 | if (lock->cpu != cpu) | |
3738 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3739 | put_lock_stats(stats); |
96645678 PZ |
3740 | |
3741 | lock->cpu = cpu; | |
c7e78cff | 3742 | lock->ip = ip; |
f20786ff PZ |
3743 | } |
3744 | ||
3745 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3746 | { | |
3747 | unsigned long flags; | |
3748 | ||
3749 | if (unlikely(!lock_stat)) | |
3750 | return; | |
3751 | ||
3752 | if (unlikely(current->lockdep_recursion)) | |
3753 | return; | |
3754 | ||
3755 | raw_local_irq_save(flags); | |
3756 | check_flags(flags); | |
3757 | current->lockdep_recursion = 1; | |
db2c4c77 | 3758 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3759 | __lock_contended(lock, ip); |
3760 | current->lockdep_recursion = 0; | |
3761 | raw_local_irq_restore(flags); | |
3762 | } | |
3763 | EXPORT_SYMBOL_GPL(lock_contended); | |
3764 | ||
c7e78cff | 3765 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3766 | { |
3767 | unsigned long flags; | |
3768 | ||
3769 | if (unlikely(!lock_stat)) | |
3770 | return; | |
3771 | ||
3772 | if (unlikely(current->lockdep_recursion)) | |
3773 | return; | |
3774 | ||
3775 | raw_local_irq_save(flags); | |
3776 | check_flags(flags); | |
3777 | current->lockdep_recursion = 1; | |
c7e78cff | 3778 | __lock_acquired(lock, ip); |
f20786ff PZ |
3779 | current->lockdep_recursion = 0; |
3780 | raw_local_irq_restore(flags); | |
3781 | } | |
3782 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3783 | #endif | |
3784 | ||
fbb9ce95 IM |
3785 | /* |
3786 | * Used by the testsuite, sanitize the validator state | |
3787 | * after a simulated failure: | |
3788 | */ | |
3789 | ||
3790 | void lockdep_reset(void) | |
3791 | { | |
3792 | unsigned long flags; | |
23d95a03 | 3793 | int i; |
fbb9ce95 IM |
3794 | |
3795 | raw_local_irq_save(flags); | |
3796 | current->curr_chain_key = 0; | |
3797 | current->lockdep_depth = 0; | |
3798 | current->lockdep_recursion = 0; | |
3799 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3800 | nr_hardirq_chains = 0; | |
3801 | nr_softirq_chains = 0; | |
3802 | nr_process_chains = 0; | |
3803 | debug_locks = 1; | |
23d95a03 IM |
3804 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3805 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3806 | raw_local_irq_restore(flags); |
3807 | } | |
3808 | ||
3809 | static void zap_class(struct lock_class *class) | |
3810 | { | |
3811 | int i; | |
3812 | ||
3813 | /* | |
3814 | * Remove all dependencies this lock is | |
3815 | * involved in: | |
3816 | */ | |
3817 | for (i = 0; i < nr_list_entries; i++) { | |
3818 | if (list_entries[i].class == class) | |
3819 | list_del_rcu(&list_entries[i].entry); | |
3820 | } | |
3821 | /* | |
3822 | * Unhash the class and remove it from the all_lock_classes list: | |
3823 | */ | |
3824 | list_del_rcu(&class->hash_entry); | |
3825 | list_del_rcu(&class->lock_entry); | |
3826 | ||
8bfe0298 | 3827 | class->key = NULL; |
fbb9ce95 IM |
3828 | } |
3829 | ||
fabe874a | 3830 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3831 | { |
3832 | return addr >= start && addr < start + size; | |
3833 | } | |
3834 | ||
3835 | void lockdep_free_key_range(void *start, unsigned long size) | |
3836 | { | |
3837 | struct lock_class *class, *next; | |
3838 | struct list_head *head; | |
3839 | unsigned long flags; | |
3840 | int i; | |
5a26db5b | 3841 | int locked; |
fbb9ce95 IM |
3842 | |
3843 | raw_local_irq_save(flags); | |
5a26db5b | 3844 | locked = graph_lock(); |
fbb9ce95 IM |
3845 | |
3846 | /* | |
3847 | * Unhash all classes that were created by this module: | |
3848 | */ | |
3849 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3850 | head = classhash_table + i; | |
3851 | if (list_empty(head)) | |
3852 | continue; | |
fabe874a | 3853 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3854 | if (within(class->key, start, size)) |
3855 | zap_class(class); | |
fabe874a AV |
3856 | else if (within(class->name, start, size)) |
3857 | zap_class(class); | |
3858 | } | |
fbb9ce95 IM |
3859 | } |
3860 | ||
5a26db5b NP |
3861 | if (locked) |
3862 | graph_unlock(); | |
fbb9ce95 IM |
3863 | raw_local_irq_restore(flags); |
3864 | } | |
3865 | ||
3866 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3867 | { | |
d6d897ce | 3868 | struct lock_class *class, *next; |
fbb9ce95 IM |
3869 | struct list_head *head; |
3870 | unsigned long flags; | |
3871 | int i, j; | |
5a26db5b | 3872 | int locked; |
fbb9ce95 IM |
3873 | |
3874 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3875 | |
3876 | /* | |
d6d897ce IM |
3877 | * Remove all classes this lock might have: |
3878 | */ | |
3879 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3880 | /* | |
3881 | * If the class exists we look it up and zap it: | |
3882 | */ | |
3883 | class = look_up_lock_class(lock, j); | |
3884 | if (class) | |
3885 | zap_class(class); | |
3886 | } | |
3887 | /* | |
3888 | * Debug check: in the end all mapped classes should | |
3889 | * be gone. | |
fbb9ce95 | 3890 | */ |
5a26db5b | 3891 | locked = graph_lock(); |
fbb9ce95 IM |
3892 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3893 | head = classhash_table + i; | |
3894 | if (list_empty(head)) | |
3895 | continue; | |
3896 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
62016250 HM |
3897 | int match = 0; |
3898 | ||
3899 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
3900 | match |= class == lock->class_cache[j]; | |
3901 | ||
3902 | if (unlikely(match)) { | |
0119fee4 PZ |
3903 | if (debug_locks_off_graph_unlock()) { |
3904 | /* | |
3905 | * We all just reset everything, how did it match? | |
3906 | */ | |
74c383f1 | 3907 | WARN_ON(1); |
0119fee4 | 3908 | } |
d6d897ce | 3909 | goto out_restore; |
fbb9ce95 IM |
3910 | } |
3911 | } | |
3912 | } | |
5a26db5b NP |
3913 | if (locked) |
3914 | graph_unlock(); | |
d6d897ce IM |
3915 | |
3916 | out_restore: | |
fbb9ce95 IM |
3917 | raw_local_irq_restore(flags); |
3918 | } | |
3919 | ||
1499993c | 3920 | void lockdep_init(void) |
fbb9ce95 IM |
3921 | { |
3922 | int i; | |
3923 | ||
3924 | /* | |
3925 | * Some architectures have their own start_kernel() | |
3926 | * code which calls lockdep_init(), while we also | |
3927 | * call lockdep_init() from the start_kernel() itself, | |
3928 | * and we want to initialize the hashes only once: | |
3929 | */ | |
3930 | if (lockdep_initialized) | |
3931 | return; | |
3932 | ||
3933 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3934 | INIT_LIST_HEAD(classhash_table + i); | |
3935 | ||
3936 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3937 | INIT_LIST_HEAD(chainhash_table + i); | |
3938 | ||
3939 | lockdep_initialized = 1; | |
3940 | } | |
3941 | ||
3942 | void __init lockdep_info(void) | |
3943 | { | |
3944 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3945 | ||
b0788caf | 3946 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3947 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3948 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3949 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3950 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3951 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3952 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3953 | ||
3954 | printk(" memory used by lock dependency info: %lu kB\n", | |
3955 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3956 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3957 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3958 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 3959 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 3960 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 3961 | + sizeof(struct circular_queue) |
4dd861d6 | 3962 | #endif |
90629209 | 3963 | ) / 1024 |
4dd861d6 | 3964 | ); |
fbb9ce95 IM |
3965 | |
3966 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3967 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3968 | ||
3969 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3970 | if (lockdep_init_error) { |
3971 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3972 | printk("Call stack leading to lockdep invocation was:\n"); | |
3973 | print_stack_trace(&lockdep_init_trace, 0); | |
3974 | } | |
fbb9ce95 IM |
3975 | #endif |
3976 | } | |
3977 | ||
fbb9ce95 IM |
3978 | static void |
3979 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3980 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3981 | { |
3982 | if (!debug_locks_off()) | |
3983 | return; | |
3984 | if (debug_locks_silent) | |
3985 | return; | |
3986 | ||
b3fbab05 PM |
3987 | printk("\n"); |
3988 | printk("=========================\n"); | |
3989 | printk("[ BUG: held lock freed! ]\n"); | |
3990 | printk("-------------------------\n"); | |
fbb9ce95 | 3991 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 3992 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3993 | print_lock(hlock); |
fbb9ce95 IM |
3994 | lockdep_print_held_locks(curr); |
3995 | ||
3996 | printk("\nstack backtrace:\n"); | |
3997 | dump_stack(); | |
3998 | } | |
3999 | ||
54561783 ON |
4000 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4001 | const void* lock_from, unsigned long lock_len) | |
4002 | { | |
4003 | return lock_from + lock_len <= mem_from || | |
4004 | mem_from + mem_len <= lock_from; | |
4005 | } | |
4006 | ||
fbb9ce95 IM |
4007 | /* |
4008 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4009 | * is destroyed or reinitialized - this code checks whether there is | |
4010 | * any held lock in the memory range of <from> to <to>: | |
4011 | */ | |
4012 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4013 | { | |
fbb9ce95 IM |
4014 | struct task_struct *curr = current; |
4015 | struct held_lock *hlock; | |
4016 | unsigned long flags; | |
4017 | int i; | |
4018 | ||
4019 | if (unlikely(!debug_locks)) | |
4020 | return; | |
4021 | ||
4022 | local_irq_save(flags); | |
4023 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4024 | hlock = curr->held_locks + i; | |
4025 | ||
54561783 ON |
4026 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4027 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4028 | continue; |
4029 | ||
54561783 | 4030 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4031 | break; |
4032 | } | |
4033 | local_irq_restore(flags); | |
4034 | } | |
ed07536e | 4035 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
4036 | |
4037 | static void print_held_locks_bug(struct task_struct *curr) | |
4038 | { | |
4039 | if (!debug_locks_off()) | |
4040 | return; | |
4041 | if (debug_locks_silent) | |
4042 | return; | |
4043 | ||
b3fbab05 PM |
4044 | printk("\n"); |
4045 | printk("=====================================\n"); | |
4046 | printk("[ BUG: lock held at task exit time! ]\n"); | |
4047 | printk("-------------------------------------\n"); | |
fbb9ce95 | 4048 | printk("%s/%d is exiting with locks still held!\n", |
ba25f9dc | 4049 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
4050 | lockdep_print_held_locks(curr); |
4051 | ||
4052 | printk("\nstack backtrace:\n"); | |
4053 | dump_stack(); | |
4054 | } | |
4055 | ||
4056 | void debug_check_no_locks_held(struct task_struct *task) | |
4057 | { | |
4058 | if (unlikely(task->lockdep_depth > 0)) | |
4059 | print_held_locks_bug(task); | |
4060 | } | |
4061 | ||
4062 | void debug_show_all_locks(void) | |
4063 | { | |
4064 | struct task_struct *g, *p; | |
4065 | int count = 10; | |
4066 | int unlock = 1; | |
4067 | ||
9c35dd7f JP |
4068 | if (unlikely(!debug_locks)) { |
4069 | printk("INFO: lockdep is turned off.\n"); | |
4070 | return; | |
4071 | } | |
fbb9ce95 IM |
4072 | printk("\nShowing all locks held in the system:\n"); |
4073 | ||
4074 | /* | |
4075 | * Here we try to get the tasklist_lock as hard as possible, | |
4076 | * if not successful after 2 seconds we ignore it (but keep | |
4077 | * trying). This is to enable a debug printout even if a | |
4078 | * tasklist_lock-holding task deadlocks or crashes. | |
4079 | */ | |
4080 | retry: | |
4081 | if (!read_trylock(&tasklist_lock)) { | |
4082 | if (count == 10) | |
4083 | printk("hm, tasklist_lock locked, retrying... "); | |
4084 | if (count) { | |
4085 | count--; | |
4086 | printk(" #%d", 10-count); | |
4087 | mdelay(200); | |
4088 | goto retry; | |
4089 | } | |
4090 | printk(" ignoring it.\n"); | |
4091 | unlock = 0; | |
46fec7ac | 4092 | } else { |
4093 | if (count != 10) | |
4094 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 4095 | } |
fbb9ce95 IM |
4096 | |
4097 | do_each_thread(g, p) { | |
85684873 IM |
4098 | /* |
4099 | * It's not reliable to print a task's held locks | |
4100 | * if it's not sleeping (or if it's not the current | |
4101 | * task): | |
4102 | */ | |
4103 | if (p->state == TASK_RUNNING && p != current) | |
4104 | continue; | |
fbb9ce95 IM |
4105 | if (p->lockdep_depth) |
4106 | lockdep_print_held_locks(p); | |
4107 | if (!unlock) | |
4108 | if (read_trylock(&tasklist_lock)) | |
4109 | unlock = 1; | |
4110 | } while_each_thread(g, p); | |
4111 | ||
4112 | printk("\n"); | |
4113 | printk("=============================================\n\n"); | |
4114 | ||
4115 | if (unlock) | |
4116 | read_unlock(&tasklist_lock); | |
4117 | } | |
fbb9ce95 IM |
4118 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
4119 | ||
82a1fcb9 IM |
4120 | /* |
4121 | * Careful: only use this function if you are sure that | |
4122 | * the task cannot run in parallel! | |
4123 | */ | |
f1b499f0 | 4124 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4125 | { |
9c35dd7f JP |
4126 | if (unlikely(!debug_locks)) { |
4127 | printk("INFO: lockdep is turned off.\n"); | |
4128 | return; | |
4129 | } | |
fbb9ce95 IM |
4130 | lockdep_print_held_locks(task); |
4131 | } | |
fbb9ce95 | 4132 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
4133 | |
4134 | void lockdep_sys_exit(void) | |
4135 | { | |
4136 | struct task_struct *curr = current; | |
4137 | ||
4138 | if (unlikely(curr->lockdep_depth)) { | |
4139 | if (!debug_locks_off()) | |
4140 | return; | |
b3fbab05 PM |
4141 | printk("\n"); |
4142 | printk("================================================\n"); | |
4143 | printk("[ BUG: lock held when returning to user space! ]\n"); | |
4144 | printk("------------------------------------------------\n"); | |
b351d164 PZ |
4145 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4146 | curr->comm, curr->pid); | |
4147 | lockdep_print_held_locks(curr); | |
4148 | } | |
4149 | } | |
0632eb3d | 4150 | |
b3fbab05 | 4151 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4152 | { |
4153 | struct task_struct *curr = current; | |
4154 | ||
2b3fc35f | 4155 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4156 | if (!debug_locks_off()) |
4157 | return; | |
2b3fc35f LJ |
4158 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4159 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 PM |
4160 | printk("\n"); |
4161 | printk("===============================\n"); | |
4162 | printk("[ INFO: suspicious RCU usage. ]\n"); | |
4163 | printk("-------------------------------\n"); | |
4164 | printk("%s:%d %s!\n", file, line, s); | |
0632eb3d | 4165 | printk("\nother info that might help us debug this:\n\n"); |
cc5b83a9 | 4166 | printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks); |
0632eb3d PM |
4167 | lockdep_print_held_locks(curr); |
4168 | printk("\nstack backtrace:\n"); | |
4169 | dump_stack(); | |
4170 | } | |
b3fbab05 | 4171 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |