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Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
d3d03d4f | 47 | #include <linux/kmemcheck.h> |
af012961 | 48 | |
fbb9ce95 IM |
49 | #include <asm/sections.h> |
50 | ||
51 | #include "lockdep_internals.h" | |
52 | ||
a8d154b0 | 53 | #define CREATE_TRACE_POINTS |
67178767 | 54 | #include <trace/events/lock.h> |
a8d154b0 | 55 | |
f20786ff PZ |
56 | #ifdef CONFIG_PROVE_LOCKING |
57 | int prove_locking = 1; | |
58 | module_param(prove_locking, int, 0644); | |
59 | #else | |
60 | #define prove_locking 0 | |
61 | #endif | |
62 | ||
63 | #ifdef CONFIG_LOCK_STAT | |
64 | int lock_stat = 1; | |
65 | module_param(lock_stat, int, 0644); | |
66 | #else | |
67 | #define lock_stat 0 | |
68 | #endif | |
69 | ||
fbb9ce95 | 70 | /* |
74c383f1 IM |
71 | * lockdep_lock: protects the lockdep graph, the hashes and the |
72 | * class/list/hash allocators. | |
fbb9ce95 IM |
73 | * |
74 | * This is one of the rare exceptions where it's justified | |
75 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 76 | * code to recurse back into the lockdep code... |
fbb9ce95 | 77 | */ |
edc35bd7 | 78 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
79 | |
80 | static int graph_lock(void) | |
81 | { | |
0199c4e6 | 82 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
83 | /* |
84 | * Make sure that if another CPU detected a bug while | |
85 | * walking the graph we dont change it (while the other | |
86 | * CPU is busy printing out stuff with the graph lock | |
87 | * dropped already) | |
88 | */ | |
89 | if (!debug_locks) { | |
0199c4e6 | 90 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
91 | return 0; |
92 | } | |
bb065afb SR |
93 | /* prevent any recursions within lockdep from causing deadlocks */ |
94 | current->lockdep_recursion++; | |
74c383f1 IM |
95 | return 1; |
96 | } | |
97 | ||
98 | static inline int graph_unlock(void) | |
99 | { | |
0119fee4 PZ |
100 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
101 | /* | |
102 | * The lockdep graph lock isn't locked while we expect it to | |
103 | * be, we're confused now, bye! | |
104 | */ | |
381a2292 | 105 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 106 | } |
381a2292 | 107 | |
bb065afb | 108 | current->lockdep_recursion--; |
0199c4e6 | 109 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
110 | return 0; |
111 | } | |
112 | ||
113 | /* | |
114 | * Turn lock debugging off and return with 0 if it was off already, | |
115 | * and also release the graph lock: | |
116 | */ | |
117 | static inline int debug_locks_off_graph_unlock(void) | |
118 | { | |
119 | int ret = debug_locks_off(); | |
120 | ||
0199c4e6 | 121 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
122 | |
123 | return ret; | |
124 | } | |
fbb9ce95 IM |
125 | |
126 | static int lockdep_initialized; | |
127 | ||
128 | unsigned long nr_list_entries; | |
af012961 | 129 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 130 | |
fbb9ce95 IM |
131 | /* |
132 | * All data structures here are protected by the global debug_lock. | |
133 | * | |
134 | * Mutex key structs only get allocated, once during bootup, and never | |
135 | * get freed - this significantly simplifies the debugging code. | |
136 | */ | |
137 | unsigned long nr_lock_classes; | |
138 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
139 | ||
f82b217e DJ |
140 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
141 | { | |
142 | if (!hlock->class_idx) { | |
0119fee4 PZ |
143 | /* |
144 | * Someone passed in garbage, we give up. | |
145 | */ | |
f82b217e DJ |
146 | DEBUG_LOCKS_WARN_ON(1); |
147 | return NULL; | |
148 | } | |
149 | return lock_classes + hlock->class_idx - 1; | |
150 | } | |
151 | ||
f20786ff | 152 | #ifdef CONFIG_LOCK_STAT |
1871e52c TH |
153 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
154 | cpu_lock_stats); | |
f20786ff | 155 | |
3365e779 PZ |
156 | static inline u64 lockstat_clock(void) |
157 | { | |
c676329a | 158 | return local_clock(); |
3365e779 PZ |
159 | } |
160 | ||
c7e78cff | 161 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
162 | { |
163 | int i; | |
164 | ||
c7e78cff PZ |
165 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
166 | if (points[i] == 0) { | |
167 | points[i] = ip; | |
f20786ff PZ |
168 | break; |
169 | } | |
c7e78cff | 170 | if (points[i] == ip) |
f20786ff PZ |
171 | break; |
172 | } | |
173 | ||
174 | return i; | |
175 | } | |
176 | ||
3365e779 | 177 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
178 | { |
179 | if (time > lt->max) | |
180 | lt->max = time; | |
181 | ||
109d71c6 | 182 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
183 | lt->min = time; |
184 | ||
185 | lt->total += time; | |
186 | lt->nr++; | |
187 | } | |
188 | ||
c46261de PZ |
189 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
190 | { | |
109d71c6 FR |
191 | if (!src->nr) |
192 | return; | |
193 | ||
194 | if (src->max > dst->max) | |
195 | dst->max = src->max; | |
196 | ||
197 | if (src->min < dst->min || !dst->nr) | |
198 | dst->min = src->min; | |
199 | ||
c46261de PZ |
200 | dst->total += src->total; |
201 | dst->nr += src->nr; | |
202 | } | |
203 | ||
204 | struct lock_class_stats lock_stats(struct lock_class *class) | |
205 | { | |
206 | struct lock_class_stats stats; | |
207 | int cpu, i; | |
208 | ||
209 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
210 | for_each_possible_cpu(cpu) { | |
211 | struct lock_class_stats *pcs = | |
1871e52c | 212 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
213 | |
214 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
215 | stats.contention_point[i] += pcs->contention_point[i]; | |
216 | ||
c7e78cff PZ |
217 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
218 | stats.contending_point[i] += pcs->contending_point[i]; | |
219 | ||
c46261de PZ |
220 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
221 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
222 | ||
223 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
224 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
225 | |
226 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
227 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
228 | } |
229 | ||
230 | return stats; | |
231 | } | |
232 | ||
233 | void clear_lock_stats(struct lock_class *class) | |
234 | { | |
235 | int cpu; | |
236 | ||
237 | for_each_possible_cpu(cpu) { | |
238 | struct lock_class_stats *cpu_stats = | |
1871e52c | 239 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
240 | |
241 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
242 | } | |
243 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 244 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
245 | } |
246 | ||
f20786ff PZ |
247 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
248 | { | |
1871e52c | 249 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
250 | } |
251 | ||
252 | static void put_lock_stats(struct lock_class_stats *stats) | |
253 | { | |
1871e52c | 254 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
255 | } |
256 | ||
257 | static void lock_release_holdtime(struct held_lock *hlock) | |
258 | { | |
259 | struct lock_class_stats *stats; | |
3365e779 | 260 | u64 holdtime; |
f20786ff PZ |
261 | |
262 | if (!lock_stat) | |
263 | return; | |
264 | ||
3365e779 | 265 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 266 | |
f82b217e | 267 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
268 | if (hlock->read) |
269 | lock_time_inc(&stats->read_holdtime, holdtime); | |
270 | else | |
271 | lock_time_inc(&stats->write_holdtime, holdtime); | |
272 | put_lock_stats(stats); | |
273 | } | |
274 | #else | |
275 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
276 | { | |
277 | } | |
278 | #endif | |
279 | ||
fbb9ce95 IM |
280 | /* |
281 | * We keep a global list of all lock classes. The list only grows, | |
282 | * never shrinks. The list is only accessed with the lockdep | |
283 | * spinlock lock held. | |
284 | */ | |
285 | LIST_HEAD(all_lock_classes); | |
286 | ||
287 | /* | |
288 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
289 | */ | |
290 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
291 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 292 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
293 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
294 | ||
295 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
296 | ||
fbb9ce95 IM |
297 | /* |
298 | * We put the lock dependency chains into a hash-table as well, to cache | |
299 | * their existence: | |
300 | */ | |
301 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
302 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 303 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
304 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
305 | ||
306 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
307 | ||
308 | /* | |
309 | * The hash key of the lock dependency chains is a hash itself too: | |
310 | * it's a hash of all locks taken up to that lock, including that lock. | |
311 | * It's a 64-bit hash, because it's important for the keys to be | |
312 | * unique. | |
313 | */ | |
314 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
315 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
316 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
317 | (key2)) |
318 | ||
1d09daa5 | 319 | void lockdep_off(void) |
fbb9ce95 IM |
320 | { |
321 | current->lockdep_recursion++; | |
322 | } | |
fbb9ce95 IM |
323 | EXPORT_SYMBOL(lockdep_off); |
324 | ||
1d09daa5 | 325 | void lockdep_on(void) |
fbb9ce95 IM |
326 | { |
327 | current->lockdep_recursion--; | |
328 | } | |
fbb9ce95 IM |
329 | EXPORT_SYMBOL(lockdep_on); |
330 | ||
fbb9ce95 IM |
331 | /* |
332 | * Debugging switches: | |
333 | */ | |
334 | ||
335 | #define VERBOSE 0 | |
33e94e96 | 336 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
337 | |
338 | #if VERBOSE | |
339 | # define HARDIRQ_VERBOSE 1 | |
340 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 341 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
342 | #else |
343 | # define HARDIRQ_VERBOSE 0 | |
344 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 345 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
346 | #endif |
347 | ||
cf40bd16 | 348 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
349 | /* |
350 | * Quick filtering for interesting events: | |
351 | */ | |
352 | static int class_filter(struct lock_class *class) | |
353 | { | |
f9829cce AK |
354 | #if 0 |
355 | /* Example */ | |
fbb9ce95 | 356 | if (class->name_version == 1 && |
f9829cce | 357 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
358 | return 1; |
359 | if (class->name_version == 1 && | |
f9829cce | 360 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 361 | return 1; |
f9829cce | 362 | #endif |
a6640897 IM |
363 | /* Filter everything else. 1 would be to allow everything else */ |
364 | return 0; | |
fbb9ce95 IM |
365 | } |
366 | #endif | |
367 | ||
368 | static int verbose(struct lock_class *class) | |
369 | { | |
370 | #if VERBOSE | |
371 | return class_filter(class); | |
372 | #endif | |
373 | return 0; | |
374 | } | |
375 | ||
fbb9ce95 IM |
376 | /* |
377 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 378 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
379 | */ |
380 | unsigned long nr_stack_trace_entries; | |
381 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
382 | ||
383 | static int save_trace(struct stack_trace *trace) | |
384 | { | |
385 | trace->nr_entries = 0; | |
386 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
387 | trace->entries = stack_trace + nr_stack_trace_entries; | |
388 | ||
5a1b3999 | 389 | trace->skip = 3; |
5a1b3999 | 390 | |
ab1b6f03 | 391 | save_stack_trace(trace); |
fbb9ce95 | 392 | |
4f84f433 PZ |
393 | /* |
394 | * Some daft arches put -1 at the end to indicate its a full trace. | |
395 | * | |
396 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
397 | * complete trace that maxes out the entries provided will be reported | |
398 | * as incomplete, friggin useless </rant> | |
399 | */ | |
ea5b41f9 TL |
400 | if (trace->nr_entries != 0 && |
401 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
402 | trace->nr_entries--; |
403 | ||
fbb9ce95 IM |
404 | trace->max_entries = trace->nr_entries; |
405 | ||
406 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 407 | |
4f84f433 | 408 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
409 | if (!debug_locks_off_graph_unlock()) |
410 | return 0; | |
411 | ||
412 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
413 | printk("turning off the locking correctness validator.\n"); | |
414 | dump_stack(); | |
415 | ||
fbb9ce95 IM |
416 | return 0; |
417 | } | |
418 | ||
419 | return 1; | |
420 | } | |
421 | ||
422 | unsigned int nr_hardirq_chains; | |
423 | unsigned int nr_softirq_chains; | |
424 | unsigned int nr_process_chains; | |
425 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
426 | |
427 | #ifdef CONFIG_DEBUG_LOCKDEP | |
428 | /* | |
429 | * We cannot printk in early bootup code. Not even early_printk() | |
430 | * might work. So we mark any initialization errors and printk | |
431 | * about it later on, in lockdep_info(). | |
432 | */ | |
433 | static int lockdep_init_error; | |
81140acc | 434 | static const char *lock_init_error; |
c71063c9 JB |
435 | static unsigned long lockdep_init_trace_data[20]; |
436 | static struct stack_trace lockdep_init_trace = { | |
437 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
438 | .entries = lockdep_init_trace_data, | |
439 | }; | |
fbb9ce95 IM |
440 | |
441 | /* | |
442 | * Various lockdep statistics: | |
443 | */ | |
bd6d29c2 | 444 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
445 | #endif |
446 | ||
447 | /* | |
448 | * Locking printouts: | |
449 | */ | |
450 | ||
fabe9c42 | 451 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
452 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
453 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
454 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
455 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 456 | |
fbb9ce95 IM |
457 | static const char *usage_str[] = |
458 | { | |
fabe9c42 PZ |
459 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
460 | #include "lockdep_states.h" | |
461 | #undef LOCKDEP_STATE | |
462 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
463 | }; |
464 | ||
465 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
466 | { | |
ffb45122 | 467 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
468 | } |
469 | ||
3ff176ca | 470 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 471 | { |
3ff176ca PZ |
472 | return 1UL << bit; |
473 | } | |
fbb9ce95 | 474 | |
3ff176ca PZ |
475 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
476 | { | |
477 | char c = '.'; | |
478 | ||
479 | if (class->usage_mask & lock_flag(bit + 2)) | |
480 | c = '+'; | |
481 | if (class->usage_mask & lock_flag(bit)) { | |
482 | c = '-'; | |
483 | if (class->usage_mask & lock_flag(bit + 2)) | |
484 | c = '?'; | |
fbb9ce95 IM |
485 | } |
486 | ||
3ff176ca PZ |
487 | return c; |
488 | } | |
cf40bd16 | 489 | |
f510b233 | 490 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 491 | { |
f510b233 | 492 | int i = 0; |
cf40bd16 | 493 | |
f510b233 PZ |
494 | #define LOCKDEP_STATE(__STATE) \ |
495 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
496 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
497 | #include "lockdep_states.h" | |
498 | #undef LOCKDEP_STATE | |
499 | ||
500 | usage[i] = '\0'; | |
fbb9ce95 IM |
501 | } |
502 | ||
e5e78d08 | 503 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
504 | { |
505 | char str[KSYM_NAME_LEN]; | |
506 | const char *name; | |
507 | ||
fbb9ce95 IM |
508 | name = class->name; |
509 | if (!name) { | |
510 | name = __get_key_name(class->key, str); | |
e5e78d08 | 511 | printk("%s", name); |
fbb9ce95 | 512 | } else { |
e5e78d08 | 513 | printk("%s", name); |
fbb9ce95 IM |
514 | if (class->name_version > 1) |
515 | printk("#%d", class->name_version); | |
516 | if (class->subclass) | |
517 | printk("/%d", class->subclass); | |
518 | } | |
e5e78d08 SR |
519 | } |
520 | ||
521 | static void print_lock_name(struct lock_class *class) | |
522 | { | |
523 | char usage[LOCK_USAGE_CHARS]; | |
524 | ||
525 | get_usage_chars(class, usage); | |
526 | ||
527 | printk(" ("); | |
528 | __print_lock_name(class); | |
f510b233 | 529 | printk("){%s}", usage); |
fbb9ce95 IM |
530 | } |
531 | ||
532 | static void print_lockdep_cache(struct lockdep_map *lock) | |
533 | { | |
534 | const char *name; | |
9281acea | 535 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
536 | |
537 | name = lock->name; | |
538 | if (!name) | |
539 | name = __get_key_name(lock->key->subkeys, str); | |
540 | ||
541 | printk("%s", name); | |
542 | } | |
543 | ||
544 | static void print_lock(struct held_lock *hlock) | |
545 | { | |
f82b217e | 546 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
547 | printk(", at: "); |
548 | print_ip_sym(hlock->acquire_ip); | |
549 | } | |
550 | ||
551 | static void lockdep_print_held_locks(struct task_struct *curr) | |
552 | { | |
553 | int i, depth = curr->lockdep_depth; | |
554 | ||
555 | if (!depth) { | |
ba25f9dc | 556 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
557 | return; |
558 | } | |
559 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 560 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
561 | |
562 | for (i = 0; i < depth; i++) { | |
563 | printk(" #%d: ", i); | |
564 | print_lock(curr->held_locks + i); | |
565 | } | |
566 | } | |
fbb9ce95 | 567 | |
fbdc4b9a | 568 | static void print_kernel_ident(void) |
8e18257d | 569 | { |
fbdc4b9a | 570 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 571 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
572 | init_utsname()->version, |
573 | print_tainted()); | |
8e18257d PZ |
574 | } |
575 | ||
576 | static int very_verbose(struct lock_class *class) | |
577 | { | |
578 | #if VERY_VERBOSE | |
579 | return class_filter(class); | |
580 | #endif | |
581 | return 0; | |
582 | } | |
583 | ||
fbb9ce95 | 584 | /* |
8e18257d | 585 | * Is this the address of a static object: |
fbb9ce95 | 586 | */ |
8e18257d | 587 | static int static_obj(void *obj) |
fbb9ce95 | 588 | { |
8e18257d PZ |
589 | unsigned long start = (unsigned long) &_stext, |
590 | end = (unsigned long) &_end, | |
591 | addr = (unsigned long) obj; | |
8e18257d | 592 | |
fbb9ce95 | 593 | /* |
8e18257d | 594 | * static variable? |
fbb9ce95 | 595 | */ |
8e18257d PZ |
596 | if ((addr >= start) && (addr < end)) |
597 | return 1; | |
fbb9ce95 | 598 | |
2a9ad18d MF |
599 | if (arch_is_kernel_data(addr)) |
600 | return 1; | |
601 | ||
fbb9ce95 | 602 | /* |
10fad5e4 | 603 | * in-kernel percpu var? |
fbb9ce95 | 604 | */ |
10fad5e4 TH |
605 | if (is_kernel_percpu_address(addr)) |
606 | return 1; | |
fbb9ce95 | 607 | |
8e18257d | 608 | /* |
10fad5e4 | 609 | * module static or percpu var? |
8e18257d | 610 | */ |
10fad5e4 | 611 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a DJ |
612 | } |
613 | ||
fbb9ce95 | 614 | /* |
8e18257d PZ |
615 | * To make lock name printouts unique, we calculate a unique |
616 | * class->name_version generation counter: | |
fbb9ce95 | 617 | */ |
8e18257d | 618 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 619 | { |
8e18257d PZ |
620 | struct lock_class *class; |
621 | int count = 0; | |
fbb9ce95 | 622 | |
8e18257d | 623 | if (!new_class->name) |
fbb9ce95 IM |
624 | return 0; |
625 | ||
8e18257d PZ |
626 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
627 | if (new_class->key - new_class->subclass == class->key) | |
628 | return class->name_version; | |
629 | if (class->name && !strcmp(class->name, new_class->name)) | |
630 | count = max(count, class->name_version); | |
631 | } | |
fbb9ce95 | 632 | |
8e18257d | 633 | return count + 1; |
fbb9ce95 IM |
634 | } |
635 | ||
8e18257d PZ |
636 | /* |
637 | * Register a lock's class in the hash-table, if the class is not present | |
638 | * yet. Otherwise we look it up. We cache the result in the lock object | |
639 | * itself, so actual lookup of the hash should be once per lock object. | |
640 | */ | |
641 | static inline struct lock_class * | |
642 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 643 | { |
8e18257d PZ |
644 | struct lockdep_subclass_key *key; |
645 | struct list_head *hash_head; | |
646 | struct lock_class *class; | |
fbb9ce95 | 647 | |
8e18257d PZ |
648 | #ifdef CONFIG_DEBUG_LOCKDEP |
649 | /* | |
650 | * If the architecture calls into lockdep before initializing | |
651 | * the hashes then we'll warn about it later. (we cannot printk | |
652 | * right now) | |
653 | */ | |
654 | if (unlikely(!lockdep_initialized)) { | |
655 | lockdep_init(); | |
656 | lockdep_init_error = 1; | |
81140acc | 657 | lock_init_error = lock->name; |
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)) | |
87cdee71 | 725 | goto out_set_class_cache; |
8e18257d PZ |
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 | ||
87cdee71 | 810 | out_set_class_cache: |
8e18257d | 811 | if (!subclass || force) |
62016250 HM |
812 | lock->class_cache[0] = class; |
813 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
814 | lock->class_cache[subclass] = class; | |
8e18257d | 815 | |
0119fee4 PZ |
816 | /* |
817 | * Hash collision, did we smoke some? We found a class with a matching | |
818 | * hash but the subclass -- which is hashed in -- didn't match. | |
819 | */ | |
8e18257d PZ |
820 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
821 | return NULL; | |
822 | ||
823 | return class; | |
824 | } | |
825 | ||
826 | #ifdef CONFIG_PROVE_LOCKING | |
827 | /* | |
828 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
829 | * with NULL on failure) | |
830 | */ | |
831 | static struct lock_list *alloc_list_entry(void) | |
832 | { | |
833 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
834 | if (!debug_locks_off_graph_unlock()) | |
835 | return NULL; | |
836 | ||
837 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
838 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 839 | dump_stack(); |
8e18257d PZ |
840 | return NULL; |
841 | } | |
842 | return list_entries + nr_list_entries++; | |
843 | } | |
844 | ||
845 | /* | |
846 | * Add a new dependency to the head of the list: | |
847 | */ | |
848 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
4726f2a6 YZ |
849 | struct list_head *head, unsigned long ip, |
850 | int distance, struct stack_trace *trace) | |
8e18257d PZ |
851 | { |
852 | struct lock_list *entry; | |
853 | /* | |
854 | * Lock not present yet - get a new dependency struct and | |
855 | * add it to the list: | |
856 | */ | |
857 | entry = alloc_list_entry(); | |
858 | if (!entry) | |
859 | return 0; | |
860 | ||
74870172 ZY |
861 | entry->class = this; |
862 | entry->distance = distance; | |
4726f2a6 | 863 | entry->trace = *trace; |
8e18257d PZ |
864 | /* |
865 | * Since we never remove from the dependency list, the list can | |
866 | * be walked lockless by other CPUs, it's only allocation | |
867 | * that must be protected by the spinlock. But this also means | |
868 | * we must make new entries visible only once writes to the | |
869 | * entry become visible - hence the RCU op: | |
870 | */ | |
871 | list_add_tail_rcu(&entry->entry, head); | |
872 | ||
873 | return 1; | |
874 | } | |
875 | ||
98c33edd PZ |
876 | /* |
877 | * For good efficiency of modular, we use power of 2 | |
878 | */ | |
af012961 PZ |
879 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
880 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
881 | ||
98c33edd PZ |
882 | /* |
883 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
884 | * breadth-first search(BFS)algorithem, by which we can build |
885 | * the shortest path from the next lock to be acquired to the | |
886 | * previous held lock if there is a circular between them. | |
98c33edd | 887 | */ |
af012961 PZ |
888 | struct circular_queue { |
889 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
890 | unsigned int front, rear; | |
891 | }; | |
892 | ||
893 | static struct circular_queue lock_cq; | |
af012961 | 894 | |
12f3dfd0 | 895 | unsigned int max_bfs_queue_depth; |
af012961 | 896 | |
e351b660 ML |
897 | static unsigned int lockdep_dependency_gen_id; |
898 | ||
af012961 PZ |
899 | static inline void __cq_init(struct circular_queue *cq) |
900 | { | |
901 | cq->front = cq->rear = 0; | |
e351b660 | 902 | lockdep_dependency_gen_id++; |
af012961 PZ |
903 | } |
904 | ||
905 | static inline int __cq_empty(struct circular_queue *cq) | |
906 | { | |
907 | return (cq->front == cq->rear); | |
908 | } | |
909 | ||
910 | static inline int __cq_full(struct circular_queue *cq) | |
911 | { | |
912 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
913 | } | |
914 | ||
915 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
916 | { | |
917 | if (__cq_full(cq)) | |
918 | return -1; | |
919 | ||
920 | cq->element[cq->rear] = elem; | |
921 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
922 | return 0; | |
923 | } | |
924 | ||
925 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
926 | { | |
927 | if (__cq_empty(cq)) | |
928 | return -1; | |
929 | ||
930 | *elem = cq->element[cq->front]; | |
931 | cq->front = (cq->front + 1) & CQ_MASK; | |
932 | return 0; | |
933 | } | |
934 | ||
935 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
936 | { | |
937 | return (cq->rear - cq->front) & CQ_MASK; | |
938 | } | |
939 | ||
940 | static inline void mark_lock_accessed(struct lock_list *lock, | |
941 | struct lock_list *parent) | |
942 | { | |
943 | unsigned long nr; | |
98c33edd | 944 | |
af012961 | 945 | nr = lock - list_entries; |
0119fee4 | 946 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 947 | lock->parent = parent; |
e351b660 | 948 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
949 | } |
950 | ||
951 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
952 | { | |
953 | unsigned long nr; | |
98c33edd | 954 | |
af012961 | 955 | nr = lock - list_entries; |
0119fee4 | 956 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 957 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
958 | } |
959 | ||
960 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
961 | { | |
962 | return child->parent; | |
963 | } | |
964 | ||
965 | static inline int get_lock_depth(struct lock_list *child) | |
966 | { | |
967 | int depth = 0; | |
968 | struct lock_list *parent; | |
969 | ||
970 | while ((parent = get_lock_parent(child))) { | |
971 | child = parent; | |
972 | depth++; | |
973 | } | |
974 | return depth; | |
975 | } | |
976 | ||
9e2d551e | 977 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
978 | void *data, |
979 | int (*match)(struct lock_list *entry, void *data), | |
980 | struct lock_list **target_entry, | |
981 | int forward) | |
c94aa5ca ML |
982 | { |
983 | struct lock_list *entry; | |
d588e461 | 984 | struct list_head *head; |
c94aa5ca ML |
985 | struct circular_queue *cq = &lock_cq; |
986 | int ret = 1; | |
987 | ||
9e2d551e | 988 | if (match(source_entry, data)) { |
c94aa5ca ML |
989 | *target_entry = source_entry; |
990 | ret = 0; | |
991 | goto exit; | |
992 | } | |
993 | ||
d588e461 ML |
994 | if (forward) |
995 | head = &source_entry->class->locks_after; | |
996 | else | |
997 | head = &source_entry->class->locks_before; | |
998 | ||
999 | if (list_empty(head)) | |
1000 | goto exit; | |
1001 | ||
1002 | __cq_init(cq); | |
c94aa5ca ML |
1003 | __cq_enqueue(cq, (unsigned long)source_entry); |
1004 | ||
1005 | while (!__cq_empty(cq)) { | |
1006 | struct lock_list *lock; | |
c94aa5ca ML |
1007 | |
1008 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1009 | ||
1010 | if (!lock->class) { | |
1011 | ret = -2; | |
1012 | goto exit; | |
1013 | } | |
1014 | ||
1015 | if (forward) | |
1016 | head = &lock->class->locks_after; | |
1017 | else | |
1018 | head = &lock->class->locks_before; | |
1019 | ||
1020 | list_for_each_entry(entry, head, entry) { | |
1021 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 1022 | unsigned int cq_depth; |
c94aa5ca | 1023 | mark_lock_accessed(entry, lock); |
9e2d551e | 1024 | if (match(entry, data)) { |
c94aa5ca ML |
1025 | *target_entry = entry; |
1026 | ret = 0; | |
1027 | goto exit; | |
1028 | } | |
1029 | ||
1030 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1031 | ret = -1; | |
1032 | goto exit; | |
1033 | } | |
12f3dfd0 ML |
1034 | cq_depth = __cq_get_elem_count(cq); |
1035 | if (max_bfs_queue_depth < cq_depth) | |
1036 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1037 | } |
1038 | } | |
1039 | } | |
1040 | exit: | |
1041 | return ret; | |
1042 | } | |
1043 | ||
d7aaba14 | 1044 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1045 | void *data, |
1046 | int (*match)(struct lock_list *entry, void *data), | |
1047 | struct lock_list **target_entry) | |
c94aa5ca | 1048 | { |
9e2d551e | 1049 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1050 | |
1051 | } | |
1052 | ||
d7aaba14 | 1053 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1054 | void *data, |
1055 | int (*match)(struct lock_list *entry, void *data), | |
1056 | struct lock_list **target_entry) | |
c94aa5ca | 1057 | { |
9e2d551e | 1058 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1059 | |
1060 | } | |
1061 | ||
8e18257d PZ |
1062 | /* |
1063 | * Recursive, forwards-direction lock-dependency checking, used for | |
1064 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1065 | * checking. | |
8e18257d | 1066 | */ |
8e18257d PZ |
1067 | |
1068 | /* | |
1069 | * Print a dependency chain entry (this is only done when a deadlock | |
1070 | * has been detected): | |
1071 | */ | |
1072 | static noinline int | |
24208ca7 | 1073 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1074 | { |
1075 | if (debug_locks_silent) | |
1076 | return 0; | |
1077 | printk("\n-> #%u", depth); | |
1078 | print_lock_name(target->class); | |
1079 | printk(":\n"); | |
1080 | print_stack_trace(&target->trace, 6); | |
1081 | ||
1082 | return 0; | |
1083 | } | |
1084 | ||
f4185812 SR |
1085 | static void |
1086 | print_circular_lock_scenario(struct held_lock *src, | |
1087 | struct held_lock *tgt, | |
1088 | struct lock_list *prt) | |
1089 | { | |
1090 | struct lock_class *source = hlock_class(src); | |
1091 | struct lock_class *target = hlock_class(tgt); | |
1092 | struct lock_class *parent = prt->class; | |
1093 | ||
1094 | /* | |
1095 | * A direct locking problem where unsafe_class lock is taken | |
1096 | * directly by safe_class lock, then all we need to show | |
1097 | * is the deadlock scenario, as it is obvious that the | |
1098 | * unsafe lock is taken under the safe lock. | |
1099 | * | |
1100 | * But if there is a chain instead, where the safe lock takes | |
1101 | * an intermediate lock (middle_class) where this lock is | |
1102 | * not the same as the safe lock, then the lock chain is | |
1103 | * used to describe the problem. Otherwise we would need | |
1104 | * to show a different CPU case for each link in the chain | |
1105 | * from the safe_class lock to the unsafe_class lock. | |
1106 | */ | |
1107 | if (parent != source) { | |
1108 | printk("Chain exists of:\n "); | |
1109 | __print_lock_name(source); | |
1110 | printk(" --> "); | |
1111 | __print_lock_name(parent); | |
1112 | printk(" --> "); | |
1113 | __print_lock_name(target); | |
1114 | printk("\n\n"); | |
1115 | } | |
1116 | ||
1117 | printk(" Possible unsafe locking scenario:\n\n"); | |
1118 | printk(" CPU0 CPU1\n"); | |
1119 | printk(" ---- ----\n"); | |
1120 | printk(" lock("); | |
1121 | __print_lock_name(target); | |
1122 | printk(");\n"); | |
1123 | printk(" lock("); | |
1124 | __print_lock_name(parent); | |
1125 | printk(");\n"); | |
1126 | printk(" lock("); | |
1127 | __print_lock_name(target); | |
1128 | printk(");\n"); | |
1129 | printk(" lock("); | |
1130 | __print_lock_name(source); | |
1131 | printk(");\n"); | |
1132 | printk("\n *** DEADLOCK ***\n\n"); | |
1133 | } | |
1134 | ||
8e18257d PZ |
1135 | /* |
1136 | * When a circular dependency is detected, print the | |
1137 | * header first: | |
1138 | */ | |
1139 | static noinline int | |
db0002a3 ML |
1140 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1141 | struct held_lock *check_src, | |
1142 | struct held_lock *check_tgt) | |
8e18257d PZ |
1143 | { |
1144 | struct task_struct *curr = current; | |
1145 | ||
c94aa5ca | 1146 | if (debug_locks_silent) |
8e18257d PZ |
1147 | return 0; |
1148 | ||
b3fbab05 PM |
1149 | printk("\n"); |
1150 | printk("======================================================\n"); | |
1151 | printk("[ INFO: possible circular locking dependency detected ]\n"); | |
fbdc4b9a | 1152 | print_kernel_ident(); |
b3fbab05 | 1153 | printk("-------------------------------------------------------\n"); |
8e18257d | 1154 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1155 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1156 | print_lock(check_src); |
8e18257d | 1157 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1158 | print_lock(check_tgt); |
8e18257d PZ |
1159 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1160 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1161 | ||
1162 | print_circular_bug_entry(entry, depth); | |
1163 | ||
1164 | return 0; | |
1165 | } | |
1166 | ||
9e2d551e ML |
1167 | static inline int class_equal(struct lock_list *entry, void *data) |
1168 | { | |
1169 | return entry->class == data; | |
1170 | } | |
1171 | ||
db0002a3 ML |
1172 | static noinline int print_circular_bug(struct lock_list *this, |
1173 | struct lock_list *target, | |
1174 | struct held_lock *check_src, | |
1175 | struct held_lock *check_tgt) | |
8e18257d PZ |
1176 | { |
1177 | struct task_struct *curr = current; | |
c94aa5ca | 1178 | struct lock_list *parent; |
f4185812 | 1179 | struct lock_list *first_parent; |
24208ca7 | 1180 | int depth; |
8e18257d | 1181 | |
c94aa5ca | 1182 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1183 | return 0; |
1184 | ||
db0002a3 | 1185 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1186 | return 0; |
1187 | ||
c94aa5ca ML |
1188 | depth = get_lock_depth(target); |
1189 | ||
db0002a3 | 1190 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1191 | |
1192 | parent = get_lock_parent(target); | |
f4185812 | 1193 | first_parent = parent; |
c94aa5ca ML |
1194 | |
1195 | while (parent) { | |
1196 | print_circular_bug_entry(parent, --depth); | |
1197 | parent = get_lock_parent(parent); | |
1198 | } | |
8e18257d PZ |
1199 | |
1200 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1201 | print_circular_lock_scenario(check_src, check_tgt, |
1202 | first_parent); | |
1203 | ||
8e18257d PZ |
1204 | lockdep_print_held_locks(curr); |
1205 | ||
1206 | printk("\nstack backtrace:\n"); | |
1207 | dump_stack(); | |
1208 | ||
1209 | return 0; | |
1210 | } | |
1211 | ||
db0002a3 ML |
1212 | static noinline int print_bfs_bug(int ret) |
1213 | { | |
1214 | if (!debug_locks_off_graph_unlock()) | |
1215 | return 0; | |
1216 | ||
0119fee4 PZ |
1217 | /* |
1218 | * Breadth-first-search failed, graph got corrupted? | |
1219 | */ | |
db0002a3 ML |
1220 | WARN(1, "lockdep bfs error:%d\n", ret); |
1221 | ||
1222 | return 0; | |
1223 | } | |
1224 | ||
ef681026 | 1225 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1226 | { |
ef681026 ML |
1227 | (*(unsigned long *)data)++; |
1228 | return 0; | |
1229 | } | |
419ca3f1 | 1230 | |
ef681026 ML |
1231 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1232 | { | |
1233 | unsigned long count = 0; | |
1234 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1235 | |
ef681026 | 1236 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1237 | |
ef681026 | 1238 | return count; |
419ca3f1 | 1239 | } |
419ca3f1 DM |
1240 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1241 | { | |
1242 | unsigned long ret, flags; | |
ef681026 ML |
1243 | struct lock_list this; |
1244 | ||
1245 | this.parent = NULL; | |
1246 | this.class = class; | |
419ca3f1 DM |
1247 | |
1248 | local_irq_save(flags); | |
0199c4e6 | 1249 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1250 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1251 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1252 | local_irq_restore(flags); |
1253 | ||
1254 | return ret; | |
1255 | } | |
1256 | ||
ef681026 | 1257 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1258 | { |
ef681026 ML |
1259 | unsigned long count = 0; |
1260 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1261 | |
ef681026 | 1262 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1263 | |
ef681026 | 1264 | return count; |
419ca3f1 DM |
1265 | } |
1266 | ||
1267 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1268 | { | |
1269 | unsigned long ret, flags; | |
ef681026 ML |
1270 | struct lock_list this; |
1271 | ||
1272 | this.parent = NULL; | |
1273 | this.class = class; | |
419ca3f1 DM |
1274 | |
1275 | local_irq_save(flags); | |
0199c4e6 | 1276 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1277 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1278 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1279 | local_irq_restore(flags); |
1280 | ||
1281 | return ret; | |
1282 | } | |
1283 | ||
8e18257d PZ |
1284 | /* |
1285 | * Prove that the dependency graph starting at <entry> can not | |
1286 | * lead to <target>. Print an error and return 0 if it does. | |
1287 | */ | |
1288 | static noinline int | |
db0002a3 ML |
1289 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1290 | struct lock_list **target_entry) | |
8e18257d | 1291 | { |
db0002a3 | 1292 | int result; |
8e18257d | 1293 | |
bd6d29c2 | 1294 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1295 | |
d7aaba14 | 1296 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1297 | |
db0002a3 ML |
1298 | return result; |
1299 | } | |
c94aa5ca | 1300 | |
81d68a96 | 1301 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1302 | /* |
1303 | * Forwards and backwards subgraph searching, for the purposes of | |
1304 | * proving that two subgraphs can be connected by a new dependency | |
1305 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1306 | */ | |
fbb9ce95 | 1307 | |
d7aaba14 ML |
1308 | static inline int usage_match(struct lock_list *entry, void *bit) |
1309 | { | |
1310 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1311 | } | |
1312 | ||
1313 | ||
1314 | ||
fbb9ce95 IM |
1315 | /* |
1316 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1317 | * at @root->class that matches @bit. |
fbb9ce95 | 1318 | * |
d7aaba14 ML |
1319 | * Return 0 if such a node exists in the subgraph, and put that node |
1320 | * into *@target_entry. | |
fbb9ce95 | 1321 | * |
d7aaba14 ML |
1322 | * Return 1 otherwise and keep *@target_entry unchanged. |
1323 | * Return <0 on error. | |
fbb9ce95 | 1324 | */ |
d7aaba14 ML |
1325 | static int |
1326 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1327 | struct lock_list **target_entry) | |
fbb9ce95 | 1328 | { |
d7aaba14 | 1329 | int result; |
fbb9ce95 | 1330 | |
bd6d29c2 | 1331 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1332 | |
d7aaba14 ML |
1333 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1334 | ||
1335 | return result; | |
fbb9ce95 IM |
1336 | } |
1337 | ||
1338 | /* | |
1339 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1340 | * at @root->class that matches @bit. |
fbb9ce95 | 1341 | * |
d7aaba14 ML |
1342 | * Return 0 if such a node exists in the subgraph, and put that node |
1343 | * into *@target_entry. | |
fbb9ce95 | 1344 | * |
d7aaba14 ML |
1345 | * Return 1 otherwise and keep *@target_entry unchanged. |
1346 | * Return <0 on error. | |
fbb9ce95 | 1347 | */ |
d7aaba14 ML |
1348 | static int |
1349 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1350 | struct lock_list **target_entry) | |
fbb9ce95 | 1351 | { |
d7aaba14 | 1352 | int result; |
fbb9ce95 | 1353 | |
bd6d29c2 | 1354 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1355 | |
d7aaba14 | 1356 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1357 | |
d7aaba14 | 1358 | return result; |
fbb9ce95 IM |
1359 | } |
1360 | ||
af012961 PZ |
1361 | static void print_lock_class_header(struct lock_class *class, int depth) |
1362 | { | |
1363 | int bit; | |
1364 | ||
1365 | printk("%*s->", depth, ""); | |
1366 | print_lock_name(class); | |
1367 | printk(" ops: %lu", class->ops); | |
1368 | printk(" {\n"); | |
1369 | ||
1370 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1371 | if (class->usage_mask & (1 << bit)) { | |
1372 | int len = depth; | |
1373 | ||
1374 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1375 | len += printk(" at:\n"); | |
1376 | print_stack_trace(class->usage_traces + bit, len); | |
1377 | } | |
1378 | } | |
1379 | printk("%*s }\n", depth, ""); | |
1380 | ||
1381 | printk("%*s ... key at: ",depth,""); | |
1382 | print_ip_sym((unsigned long)class->key); | |
1383 | } | |
1384 | ||
1385 | /* | |
1386 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1387 | */ | |
1388 | static void __used | |
1389 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1390 | struct lock_list *root) | |
1391 | { | |
1392 | struct lock_list *entry = leaf; | |
1393 | int depth; | |
1394 | ||
1395 | /*compute depth from generated tree by BFS*/ | |
1396 | depth = get_lock_depth(leaf); | |
1397 | ||
1398 | do { | |
1399 | print_lock_class_header(entry->class, depth); | |
1400 | printk("%*s ... acquired at:\n", depth, ""); | |
1401 | print_stack_trace(&entry->trace, 2); | |
1402 | printk("\n"); | |
1403 | ||
1404 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1405 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1406 | break; |
1407 | } | |
1408 | ||
1409 | entry = get_lock_parent(entry); | |
1410 | depth--; | |
1411 | } while (entry && (depth >= 0)); | |
1412 | ||
1413 | return; | |
1414 | } | |
d7aaba14 | 1415 | |
3003eba3 SR |
1416 | static void |
1417 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1418 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1419 | struct lock_class *prev_class, |
1420 | struct lock_class *next_class) | |
3003eba3 SR |
1421 | { |
1422 | struct lock_class *safe_class = safe_entry->class; | |
1423 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1424 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1425 | |
1426 | if (middle_class == safe_class) | |
dad3d743 | 1427 | middle_class = next_class; |
3003eba3 SR |
1428 | |
1429 | /* | |
1430 | * A direct locking problem where unsafe_class lock is taken | |
1431 | * directly by safe_class lock, then all we need to show | |
1432 | * is the deadlock scenario, as it is obvious that the | |
1433 | * unsafe lock is taken under the safe lock. | |
1434 | * | |
1435 | * But if there is a chain instead, where the safe lock takes | |
1436 | * an intermediate lock (middle_class) where this lock is | |
1437 | * not the same as the safe lock, then the lock chain is | |
1438 | * used to describe the problem. Otherwise we would need | |
1439 | * to show a different CPU case for each link in the chain | |
1440 | * from the safe_class lock to the unsafe_class lock. | |
1441 | */ | |
1442 | if (middle_class != unsafe_class) { | |
1443 | printk("Chain exists of:\n "); | |
1444 | __print_lock_name(safe_class); | |
1445 | printk(" --> "); | |
1446 | __print_lock_name(middle_class); | |
1447 | printk(" --> "); | |
1448 | __print_lock_name(unsafe_class); | |
1449 | printk("\n\n"); | |
1450 | } | |
1451 | ||
1452 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1453 | printk(" CPU0 CPU1\n"); | |
1454 | printk(" ---- ----\n"); | |
1455 | printk(" lock("); | |
1456 | __print_lock_name(unsafe_class); | |
1457 | printk(");\n"); | |
1458 | printk(" local_irq_disable();\n"); | |
1459 | printk(" lock("); | |
1460 | __print_lock_name(safe_class); | |
1461 | printk(");\n"); | |
1462 | printk(" lock("); | |
1463 | __print_lock_name(middle_class); | |
1464 | printk(");\n"); | |
1465 | printk(" <Interrupt>\n"); | |
1466 | printk(" lock("); | |
1467 | __print_lock_name(safe_class); | |
1468 | printk(");\n"); | |
1469 | printk("\n *** DEADLOCK ***\n\n"); | |
1470 | } | |
1471 | ||
fbb9ce95 IM |
1472 | static int |
1473 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1474 | struct lock_list *prev_root, |
1475 | struct lock_list *next_root, | |
1476 | struct lock_list *backwards_entry, | |
1477 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1478 | struct held_lock *prev, |
1479 | struct held_lock *next, | |
1480 | enum lock_usage_bit bit1, | |
1481 | enum lock_usage_bit bit2, | |
1482 | const char *irqclass) | |
1483 | { | |
74c383f1 | 1484 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1485 | return 0; |
1486 | ||
b3fbab05 PM |
1487 | printk("\n"); |
1488 | printk("======================================================\n"); | |
1489 | printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
fbb9ce95 | 1490 | irqclass, irqclass); |
fbdc4b9a | 1491 | print_kernel_ident(); |
b3fbab05 | 1492 | printk("------------------------------------------------------\n"); |
fbb9ce95 | 1493 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1494 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1495 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1496 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1497 | curr->hardirqs_enabled, | |
1498 | curr->softirqs_enabled); | |
1499 | print_lock(next); | |
1500 | ||
1501 | printk("\nand this task is already holding:\n"); | |
1502 | print_lock(prev); | |
1503 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1504 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1505 | printk(" ->"); |
f82b217e | 1506 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1507 | printk("\n"); |
1508 | ||
1509 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1510 | irqclass); | |
24208ca7 | 1511 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1512 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1513 | ||
24208ca7 | 1514 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1515 | |
1516 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1517 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1518 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1519 | printk("..."); | |
1520 | ||
24208ca7 | 1521 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1522 | |
1523 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1524 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1525 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1526 | |
fbb9ce95 IM |
1527 | lockdep_print_held_locks(curr); |
1528 | ||
24208ca7 ML |
1529 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1530 | printk(" and the holding lock:\n"); | |
1531 | if (!save_trace(&prev_root->trace)) | |
1532 | return 0; | |
1533 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1534 | |
24208ca7 ML |
1535 | printk("\nthe dependencies between the lock to be acquired"); |
1536 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1537 | if (!save_trace(&next_root->trace)) | |
1538 | return 0; | |
1539 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1540 | |
1541 | printk("\nstack backtrace:\n"); | |
1542 | dump_stack(); | |
1543 | ||
1544 | return 0; | |
1545 | } | |
1546 | ||
1547 | static int | |
1548 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1549 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1550 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1551 | { | |
1552 | int ret; | |
24208ca7 | 1553 | struct lock_list this, that; |
d7aaba14 | 1554 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1555 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1556 | |
1557 | this.parent = NULL; | |
1558 | ||
1559 | this.class = hlock_class(prev); | |
1560 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1561 | if (ret < 0) |
1562 | return print_bfs_bug(ret); | |
1563 | if (ret == 1) | |
1564 | return ret; | |
d7aaba14 | 1565 | |
24208ca7 ML |
1566 | that.parent = NULL; |
1567 | that.class = hlock_class(next); | |
1568 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1569 | if (ret < 0) |
1570 | return print_bfs_bug(ret); | |
1571 | if (ret == 1) | |
1572 | return ret; | |
fbb9ce95 | 1573 | |
24208ca7 ML |
1574 | return print_bad_irq_dependency(curr, &this, &that, |
1575 | target_entry, target_entry1, | |
1576 | prev, next, | |
fbb9ce95 IM |
1577 | bit_backwards, bit_forwards, irqclass); |
1578 | } | |
1579 | ||
4f367d8a PZ |
1580 | static const char *state_names[] = { |
1581 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1582 | __stringify(__STATE), |
4f367d8a PZ |
1583 | #include "lockdep_states.h" |
1584 | #undef LOCKDEP_STATE | |
1585 | }; | |
1586 | ||
1587 | static const char *state_rnames[] = { | |
1588 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1589 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1590 | #include "lockdep_states.h" |
1591 | #undef LOCKDEP_STATE | |
1592 | }; | |
1593 | ||
1594 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1595 | { |
4f367d8a PZ |
1596 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1597 | } | |
8e18257d | 1598 | |
4f367d8a PZ |
1599 | static int exclusive_bit(int new_bit) |
1600 | { | |
8e18257d | 1601 | /* |
4f367d8a PZ |
1602 | * USED_IN |
1603 | * USED_IN_READ | |
1604 | * ENABLED | |
1605 | * ENABLED_READ | |
1606 | * | |
1607 | * bit 0 - write/read | |
1608 | * bit 1 - used_in/enabled | |
1609 | * bit 2+ state | |
8e18257d | 1610 | */ |
4f367d8a PZ |
1611 | |
1612 | int state = new_bit & ~3; | |
1613 | int dir = new_bit & 2; | |
8e18257d PZ |
1614 | |
1615 | /* | |
4f367d8a | 1616 | * keep state, bit flip the direction and strip read. |
8e18257d | 1617 | */ |
4f367d8a PZ |
1618 | return state | (dir ^ 2); |
1619 | } | |
1620 | ||
1621 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1622 | struct held_lock *next, enum lock_usage_bit bit) | |
1623 | { | |
8e18257d | 1624 | /* |
4f367d8a PZ |
1625 | * Prove that the new dependency does not connect a hardirq-safe |
1626 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1627 | * the backwards-subgraph starting at <prev>, and the |
1628 | * forwards-subgraph starting at <next>: | |
1629 | */ | |
4f367d8a PZ |
1630 | if (!check_usage(curr, prev, next, bit, |
1631 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1632 | return 0; |
1633 | ||
4f367d8a PZ |
1634 | bit++; /* _READ */ |
1635 | ||
cf40bd16 | 1636 | /* |
4f367d8a PZ |
1637 | * Prove that the new dependency does not connect a hardirq-safe-read |
1638 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1639 | * the backwards-subgraph starting at <prev>, and the |
1640 | * forwards-subgraph starting at <next>: | |
1641 | */ | |
4f367d8a PZ |
1642 | if (!check_usage(curr, prev, next, bit, |
1643 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1644 | return 0; |
1645 | ||
4f367d8a PZ |
1646 | return 1; |
1647 | } | |
1648 | ||
1649 | static int | |
1650 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1651 | struct held_lock *next) | |
1652 | { | |
1653 | #define LOCKDEP_STATE(__STATE) \ | |
1654 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1655 | return 0; |
4f367d8a PZ |
1656 | #include "lockdep_states.h" |
1657 | #undef LOCKDEP_STATE | |
cf40bd16 | 1658 | |
8e18257d PZ |
1659 | return 1; |
1660 | } | |
1661 | ||
1662 | static void inc_chains(void) | |
1663 | { | |
1664 | if (current->hardirq_context) | |
1665 | nr_hardirq_chains++; | |
1666 | else { | |
1667 | if (current->softirq_context) | |
1668 | nr_softirq_chains++; | |
1669 | else | |
1670 | nr_process_chains++; | |
1671 | } | |
1672 | } | |
1673 | ||
1674 | #else | |
1675 | ||
1676 | static inline int | |
1677 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1678 | struct held_lock *next) | |
1679 | { | |
1680 | return 1; | |
1681 | } | |
1682 | ||
1683 | static inline void inc_chains(void) | |
1684 | { | |
1685 | nr_process_chains++; | |
1686 | } | |
1687 | ||
fbb9ce95 IM |
1688 | #endif |
1689 | ||
48702ecf SR |
1690 | static void |
1691 | print_deadlock_scenario(struct held_lock *nxt, | |
1692 | struct held_lock *prv) | |
1693 | { | |
1694 | struct lock_class *next = hlock_class(nxt); | |
1695 | struct lock_class *prev = hlock_class(prv); | |
1696 | ||
1697 | printk(" Possible unsafe locking scenario:\n\n"); | |
1698 | printk(" CPU0\n"); | |
1699 | printk(" ----\n"); | |
1700 | printk(" lock("); | |
1701 | __print_lock_name(prev); | |
1702 | printk(");\n"); | |
1703 | printk(" lock("); | |
1704 | __print_lock_name(next); | |
1705 | printk(");\n"); | |
1706 | printk("\n *** DEADLOCK ***\n\n"); | |
1707 | printk(" May be due to missing lock nesting notation\n\n"); | |
1708 | } | |
1709 | ||
fbb9ce95 IM |
1710 | static int |
1711 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1712 | struct held_lock *next) | |
1713 | { | |
74c383f1 | 1714 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1715 | return 0; |
1716 | ||
b3fbab05 PM |
1717 | printk("\n"); |
1718 | printk("=============================================\n"); | |
1719 | printk("[ INFO: possible recursive locking detected ]\n"); | |
fbdc4b9a | 1720 | print_kernel_ident(); |
b3fbab05 | 1721 | printk("---------------------------------------------\n"); |
fbb9ce95 | 1722 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1723 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1724 | print_lock(next); |
1725 | printk("\nbut task is already holding lock:\n"); | |
1726 | print_lock(prev); | |
1727 | ||
1728 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1729 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1730 | lockdep_print_held_locks(curr); |
1731 | ||
1732 | printk("\nstack backtrace:\n"); | |
1733 | dump_stack(); | |
1734 | ||
1735 | return 0; | |
1736 | } | |
1737 | ||
1738 | /* | |
1739 | * Check whether we are holding such a class already. | |
1740 | * | |
1741 | * (Note that this has to be done separately, because the graph cannot | |
1742 | * detect such classes of deadlocks.) | |
1743 | * | |
1744 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1745 | */ | |
1746 | static int | |
1747 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1748 | struct lockdep_map *next_instance, int read) | |
1749 | { | |
1750 | struct held_lock *prev; | |
7531e2f3 | 1751 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1752 | int i; |
1753 | ||
1754 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1755 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1756 | |
1757 | if (prev->instance == next->nest_lock) | |
1758 | nest = prev; | |
1759 | ||
f82b217e | 1760 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1761 | continue; |
7531e2f3 | 1762 | |
fbb9ce95 IM |
1763 | /* |
1764 | * Allow read-after-read recursion of the same | |
6c9076ec | 1765 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1766 | */ |
6c9076ec | 1767 | if ((read == 2) && prev->read) |
fbb9ce95 | 1768 | return 2; |
7531e2f3 PZ |
1769 | |
1770 | /* | |
1771 | * We're holding the nest_lock, which serializes this lock's | |
1772 | * nesting behaviour. | |
1773 | */ | |
1774 | if (nest) | |
1775 | return 2; | |
1776 | ||
fbb9ce95 IM |
1777 | return print_deadlock_bug(curr, prev, next); |
1778 | } | |
1779 | return 1; | |
1780 | } | |
1781 | ||
1782 | /* | |
1783 | * There was a chain-cache miss, and we are about to add a new dependency | |
1784 | * to a previous lock. We recursively validate the following rules: | |
1785 | * | |
1786 | * - would the adding of the <prev> -> <next> dependency create a | |
1787 | * circular dependency in the graph? [== circular deadlock] | |
1788 | * | |
1789 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1790 | * (in the full backwards-subgraph starting at <prev>) with any | |
1791 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1792 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1793 | * | |
1794 | * - does the new prev->next dependency connect any softirq-safe lock | |
1795 | * (in the full backwards-subgraph starting at <prev>) with any | |
1796 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1797 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1798 | * | |
1799 | * any of these scenarios could lead to a deadlock. | |
1800 | * | |
1801 | * Then if all the validations pass, we add the forwards and backwards | |
1802 | * dependency. | |
1803 | */ | |
1804 | static int | |
1805 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
4726f2a6 | 1806 | struct held_lock *next, int distance, int trylock_loop) |
fbb9ce95 IM |
1807 | { |
1808 | struct lock_list *entry; | |
1809 | int ret; | |
db0002a3 ML |
1810 | struct lock_list this; |
1811 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1812 | /* |
1813 | * Static variable, serialized by the graph_lock(). | |
1814 | * | |
1815 | * We use this static variable to save the stack trace in case | |
1816 | * we call into this function multiple times due to encountering | |
1817 | * trylocks in the held lock stack. | |
1818 | */ | |
1819 | static struct stack_trace trace; | |
fbb9ce95 IM |
1820 | |
1821 | /* | |
1822 | * Prove that the new <prev> -> <next> dependency would not | |
1823 | * create a circular dependency in the graph. (We do this by | |
1824 | * forward-recursing into the graph starting at <next>, and | |
1825 | * checking whether we can reach <prev>.) | |
1826 | * | |
1827 | * We are using global variables to control the recursion, to | |
1828 | * keep the stackframe size of the recursive functions low: | |
1829 | */ | |
db0002a3 ML |
1830 | this.class = hlock_class(next); |
1831 | this.parent = NULL; | |
1832 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1833 | if (unlikely(!ret)) | |
1834 | return print_circular_bug(&this, target_entry, next, prev); | |
1835 | else if (unlikely(ret < 0)) | |
1836 | return print_bfs_bug(ret); | |
c94aa5ca | 1837 | |
8e18257d | 1838 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1839 | return 0; |
1840 | ||
fbb9ce95 IM |
1841 | /* |
1842 | * For recursive read-locks we do all the dependency checks, | |
1843 | * but we dont store read-triggered dependencies (only | |
1844 | * write-triggered dependencies). This ensures that only the | |
1845 | * write-side dependencies matter, and that if for example a | |
1846 | * write-lock never takes any other locks, then the reads are | |
1847 | * equivalent to a NOP. | |
1848 | */ | |
1849 | if (next->read == 2 || prev->read == 2) | |
1850 | return 1; | |
1851 | /* | |
1852 | * Is the <prev> -> <next> dependency already present? | |
1853 | * | |
1854 | * (this may occur even though this is a new chain: consider | |
1855 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1856 | * chains - the second one will be new, but L1 already has | |
1857 | * L2 added to its dependency list, due to the first chain.) | |
1858 | */ | |
f82b217e DJ |
1859 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1860 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1861 | if (distance == 1) |
1862 | entry->distance = 1; | |
fbb9ce95 | 1863 | return 2; |
068135e6 | 1864 | } |
fbb9ce95 IM |
1865 | } |
1866 | ||
4726f2a6 YZ |
1867 | if (!trylock_loop && !save_trace(&trace)) |
1868 | return 0; | |
1869 | ||
fbb9ce95 IM |
1870 | /* |
1871 | * Ok, all validations passed, add the new lock | |
1872 | * to the previous lock's dependency list: | |
1873 | */ | |
f82b217e DJ |
1874 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1875 | &hlock_class(prev)->locks_after, | |
4726f2a6 | 1876 | next->acquire_ip, distance, &trace); |
068135e6 | 1877 | |
fbb9ce95 IM |
1878 | if (!ret) |
1879 | return 0; | |
910b1b2e | 1880 | |
f82b217e DJ |
1881 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1882 | &hlock_class(next)->locks_before, | |
4726f2a6 | 1883 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1884 | if (!ret) |
1885 | return 0; | |
fbb9ce95 IM |
1886 | |
1887 | /* | |
8e18257d PZ |
1888 | * Debugging printouts: |
1889 | */ | |
f82b217e | 1890 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1891 | graph_unlock(); |
1892 | printk("\n new dependency: "); | |
f82b217e | 1893 | print_lock_name(hlock_class(prev)); |
8e18257d | 1894 | printk(" => "); |
f82b217e | 1895 | print_lock_name(hlock_class(next)); |
8e18257d | 1896 | printk("\n"); |
fbb9ce95 | 1897 | dump_stack(); |
8e18257d | 1898 | return graph_lock(); |
fbb9ce95 | 1899 | } |
8e18257d PZ |
1900 | return 1; |
1901 | } | |
fbb9ce95 | 1902 | |
8e18257d PZ |
1903 | /* |
1904 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1905 | * The ones that are relevant are (in increasing distance from curr): | |
1906 | * all consecutive trylock entries and the final non-trylock entry - or | |
1907 | * the end of this context's lock-chain - whichever comes first. | |
1908 | */ | |
1909 | static int | |
1910 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1911 | { | |
1912 | int depth = curr->lockdep_depth; | |
4726f2a6 | 1913 | int trylock_loop = 0; |
8e18257d | 1914 | struct held_lock *hlock; |
d6d897ce | 1915 | |
fbb9ce95 | 1916 | /* |
8e18257d PZ |
1917 | * Debugging checks. |
1918 | * | |
1919 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1920 | */ |
8e18257d PZ |
1921 | if (!depth) |
1922 | goto out_bug; | |
fbb9ce95 | 1923 | /* |
8e18257d PZ |
1924 | * At least two relevant locks must exist for this |
1925 | * to be a head: | |
fbb9ce95 | 1926 | */ |
8e18257d PZ |
1927 | if (curr->held_locks[depth].irq_context != |
1928 | curr->held_locks[depth-1].irq_context) | |
1929 | goto out_bug; | |
74c383f1 | 1930 | |
8e18257d PZ |
1931 | for (;;) { |
1932 | int distance = curr->lockdep_depth - depth + 1; | |
1933 | hlock = curr->held_locks + depth-1; | |
1934 | /* | |
1935 | * Only non-recursive-read entries get new dependencies | |
1936 | * added: | |
1937 | */ | |
1938 | if (hlock->read != 2) { | |
4726f2a6 YZ |
1939 | if (!check_prev_add(curr, hlock, next, |
1940 | distance, trylock_loop)) | |
8e18257d PZ |
1941 | return 0; |
1942 | /* | |
1943 | * Stop after the first non-trylock entry, | |
1944 | * as non-trylock entries have added their | |
1945 | * own direct dependencies already, so this | |
1946 | * lock is connected to them indirectly: | |
1947 | */ | |
1948 | if (!hlock->trylock) | |
1949 | break; | |
74c383f1 | 1950 | } |
8e18257d PZ |
1951 | depth--; |
1952 | /* | |
1953 | * End of lock-stack? | |
1954 | */ | |
1955 | if (!depth) | |
1956 | break; | |
1957 | /* | |
1958 | * Stop the search if we cross into another context: | |
1959 | */ | |
1960 | if (curr->held_locks[depth].irq_context != | |
1961 | curr->held_locks[depth-1].irq_context) | |
1962 | break; | |
4726f2a6 | 1963 | trylock_loop = 1; |
fbb9ce95 | 1964 | } |
8e18257d PZ |
1965 | return 1; |
1966 | out_bug: | |
1967 | if (!debug_locks_off_graph_unlock()) | |
1968 | return 0; | |
fbb9ce95 | 1969 | |
0119fee4 PZ |
1970 | /* |
1971 | * Clearly we all shouldn't be here, but since we made it we | |
1972 | * can reliable say we messed up our state. See the above two | |
1973 | * gotos for reasons why we could possibly end up here. | |
1974 | */ | |
8e18257d | 1975 | WARN_ON(1); |
fbb9ce95 | 1976 | |
8e18257d | 1977 | return 0; |
fbb9ce95 IM |
1978 | } |
1979 | ||
8e18257d | 1980 | unsigned long nr_lock_chains; |
443cd507 | 1981 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1982 | int nr_chain_hlocks; |
443cd507 HY |
1983 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1984 | ||
1985 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1986 | { | |
1987 | return lock_classes + chain_hlocks[chain->base + i]; | |
1988 | } | |
8e18257d | 1989 | |
fbb9ce95 IM |
1990 | /* |
1991 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1992 | * add it and return 1 - in this case the new dependency chain is |
1993 | * validated. If the key is already hashed, return 0. | |
1994 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1995 | */ |
443cd507 HY |
1996 | static inline int lookup_chain_cache(struct task_struct *curr, |
1997 | struct held_lock *hlock, | |
1998 | u64 chain_key) | |
fbb9ce95 | 1999 | { |
f82b217e | 2000 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
2001 | struct list_head *hash_head = chainhashentry(chain_key); |
2002 | struct lock_chain *chain; | |
443cd507 | 2003 | struct held_lock *hlock_curr, *hlock_next; |
e0944ee6 | 2004 | int i, j; |
fbb9ce95 | 2005 | |
0119fee4 PZ |
2006 | /* |
2007 | * We might need to take the graph lock, ensure we've got IRQs | |
2008 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2009 | * lockdep won't complain about its own locking errors. | |
2010 | */ | |
381a2292 JP |
2011 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2012 | return 0; | |
fbb9ce95 IM |
2013 | /* |
2014 | * We can walk it lock-free, because entries only get added | |
2015 | * to the hash: | |
2016 | */ | |
2017 | list_for_each_entry(chain, hash_head, entry) { | |
2018 | if (chain->chain_key == chain_key) { | |
2019 | cache_hit: | |
bd6d29c2 | 2020 | debug_atomic_inc(chain_lookup_hits); |
81fc685a | 2021 | if (very_verbose(class)) |
755cd900 AM |
2022 | printk("\nhash chain already cached, key: " |
2023 | "%016Lx tail class: [%p] %s\n", | |
2024 | (unsigned long long)chain_key, | |
2025 | class->key, class->name); | |
fbb9ce95 IM |
2026 | return 0; |
2027 | } | |
2028 | } | |
81fc685a | 2029 | if (very_verbose(class)) |
755cd900 AM |
2030 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2031 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2032 | /* |
2033 | * Allocate a new chain entry from the static array, and add | |
2034 | * it to the hash: | |
2035 | */ | |
74c383f1 IM |
2036 | if (!graph_lock()) |
2037 | return 0; | |
fbb9ce95 IM |
2038 | /* |
2039 | * We have to walk the chain again locked - to avoid duplicates: | |
2040 | */ | |
2041 | list_for_each_entry(chain, hash_head, entry) { | |
2042 | if (chain->chain_key == chain_key) { | |
74c383f1 | 2043 | graph_unlock(); |
fbb9ce95 IM |
2044 | goto cache_hit; |
2045 | } | |
2046 | } | |
2047 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2048 | if (!debug_locks_off_graph_unlock()) |
2049 | return 0; | |
2050 | ||
fbb9ce95 IM |
2051 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
2052 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2053 | dump_stack(); |
fbb9ce95 IM |
2054 | return 0; |
2055 | } | |
2056 | chain = lock_chains + nr_lock_chains++; | |
2057 | chain->chain_key = chain_key; | |
443cd507 HY |
2058 | chain->irq_context = hlock->irq_context; |
2059 | /* Find the first held_lock of current chain */ | |
2060 | hlock_next = hlock; | |
2061 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2062 | hlock_curr = curr->held_locks + i; | |
2063 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
2064 | break; | |
2065 | hlock_next = hlock; | |
2066 | } | |
2067 | i++; | |
2068 | chain->depth = curr->lockdep_depth + 1 - i; | |
e0944ee6 SR |
2069 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2070 | chain->base = nr_chain_hlocks; | |
2071 | nr_chain_hlocks += chain->depth; | |
443cd507 | 2072 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2073 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2074 | chain_hlocks[chain->base + j] = lock_id; |
2075 | } | |
2076 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2077 | } | |
fbb9ce95 | 2078 | list_add_tail_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2079 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2080 | inc_chains(); |
2081 | ||
2082 | return 1; | |
2083 | } | |
2084 | ||
2085 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2086 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2087 | { |
2088 | /* | |
2089 | * Trylock needs to maintain the stack of held locks, but it | |
2090 | * does not add new dependencies, because trylock can be done | |
2091 | * in any order. | |
2092 | * | |
2093 | * We look up the chain_key and do the O(N^2) check and update of | |
2094 | * the dependencies only if this is a new dependency chain. | |
2095 | * (If lookup_chain_cache() returns with 1 it acquires | |
2096 | * graph_lock for us) | |
2097 | */ | |
2098 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 2099 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2100 | /* |
2101 | * Check whether last held lock: | |
2102 | * | |
2103 | * - is irq-safe, if this lock is irq-unsafe | |
2104 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2105 | * | |
2106 | * And check whether the new lock's dependency graph | |
2107 | * could lead back to the previous lock. | |
2108 | * | |
2109 | * any of these scenarios could lead to a deadlock. If | |
2110 | * All validations | |
2111 | */ | |
2112 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2113 | ||
2114 | if (!ret) | |
2115 | return 0; | |
2116 | /* | |
2117 | * Mark recursive read, as we jump over it when | |
2118 | * building dependencies (just like we jump over | |
2119 | * trylock entries): | |
2120 | */ | |
2121 | if (ret == 2) | |
2122 | hlock->read = 2; | |
2123 | /* | |
2124 | * Add dependency only if this lock is not the head | |
2125 | * of the chain, and if it's not a secondary read-lock: | |
2126 | */ | |
2127 | if (!chain_head && ret != 2) | |
2128 | if (!check_prevs_add(curr, hlock)) | |
2129 | return 0; | |
2130 | graph_unlock(); | |
2131 | } else | |
2132 | /* after lookup_chain_cache(): */ | |
2133 | if (unlikely(!debug_locks)) | |
2134 | return 0; | |
fbb9ce95 IM |
2135 | |
2136 | return 1; | |
2137 | } | |
8e18257d PZ |
2138 | #else |
2139 | static inline int validate_chain(struct task_struct *curr, | |
2140 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2141 | int chain_head, u64 chain_key) |
8e18257d PZ |
2142 | { |
2143 | return 1; | |
2144 | } | |
ca58abcb | 2145 | #endif |
fbb9ce95 IM |
2146 | |
2147 | /* | |
2148 | * We are building curr_chain_key incrementally, so double-check | |
2149 | * it from scratch, to make sure that it's done correctly: | |
2150 | */ | |
1d09daa5 | 2151 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2152 | { |
2153 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2154 | struct held_lock *hlock, *prev_hlock = NULL; | |
2155 | unsigned int i, id; | |
2156 | u64 chain_key = 0; | |
2157 | ||
2158 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2159 | hlock = curr->held_locks + i; | |
2160 | if (chain_key != hlock->prev_chain_key) { | |
2161 | debug_locks_off(); | |
0119fee4 PZ |
2162 | /* |
2163 | * We got mighty confused, our chain keys don't match | |
2164 | * with what we expect, someone trample on our task state? | |
2165 | */ | |
2df8b1d6 | 2166 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2167 | curr->lockdep_depth, i, |
2168 | (unsigned long long)chain_key, | |
2169 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2170 | return; |
2171 | } | |
f82b217e | 2172 | id = hlock->class_idx - 1; |
0119fee4 PZ |
2173 | /* |
2174 | * Whoops ran out of static storage again? | |
2175 | */ | |
381a2292 JP |
2176 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
2177 | return; | |
2178 | ||
fbb9ce95 IM |
2179 | if (prev_hlock && (prev_hlock->irq_context != |
2180 | hlock->irq_context)) | |
2181 | chain_key = 0; | |
2182 | chain_key = iterate_chain_key(chain_key, id); | |
2183 | prev_hlock = hlock; | |
2184 | } | |
2185 | if (chain_key != curr->curr_chain_key) { | |
2186 | debug_locks_off(); | |
0119fee4 PZ |
2187 | /* |
2188 | * More smoking hash instead of calculating it, damn see these | |
2189 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2190 | */ | |
2df8b1d6 | 2191 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2192 | curr->lockdep_depth, i, |
2193 | (unsigned long long)chain_key, | |
2194 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2195 | } |
2196 | #endif | |
2197 | } | |
2198 | ||
282b5c2f SR |
2199 | static void |
2200 | print_usage_bug_scenario(struct held_lock *lock) | |
2201 | { | |
2202 | struct lock_class *class = hlock_class(lock); | |
2203 | ||
2204 | printk(" Possible unsafe locking scenario:\n\n"); | |
2205 | printk(" CPU0\n"); | |
2206 | printk(" ----\n"); | |
2207 | printk(" lock("); | |
2208 | __print_lock_name(class); | |
2209 | printk(");\n"); | |
2210 | printk(" <Interrupt>\n"); | |
2211 | printk(" lock("); | |
2212 | __print_lock_name(class); | |
2213 | printk(");\n"); | |
2214 | printk("\n *** DEADLOCK ***\n\n"); | |
2215 | } | |
2216 | ||
8e18257d PZ |
2217 | static int |
2218 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2219 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2220 | { | |
2221 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2222 | return 0; | |
2223 | ||
b3fbab05 PM |
2224 | printk("\n"); |
2225 | printk("=================================\n"); | |
2226 | printk("[ INFO: inconsistent lock state ]\n"); | |
fbdc4b9a | 2227 | print_kernel_ident(); |
b3fbab05 | 2228 | printk("---------------------------------\n"); |
8e18257d PZ |
2229 | |
2230 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2231 | usage_str[prev_bit], usage_str[new_bit]); | |
2232 | ||
2233 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2234 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2235 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2236 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2237 | trace_hardirqs_enabled(curr), | |
2238 | trace_softirqs_enabled(curr)); | |
2239 | print_lock(this); | |
2240 | ||
2241 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2242 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2243 | |
2244 | print_irqtrace_events(curr); | |
2245 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2246 | print_usage_bug_scenario(this); |
2247 | ||
8e18257d PZ |
2248 | lockdep_print_held_locks(curr); |
2249 | ||
2250 | printk("\nstack backtrace:\n"); | |
2251 | dump_stack(); | |
2252 | ||
2253 | return 0; | |
2254 | } | |
2255 | ||
2256 | /* | |
2257 | * Print out an error if an invalid bit is set: | |
2258 | */ | |
2259 | static inline int | |
2260 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2261 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2262 | { | |
f82b217e | 2263 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2264 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2265 | return 1; | |
2266 | } | |
2267 | ||
2268 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2269 | enum lock_usage_bit new_bit); | |
2270 | ||
81d68a96 | 2271 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2272 | |
2273 | /* | |
2274 | * print irq inversion bug: | |
2275 | */ | |
2276 | static int | |
24208ca7 ML |
2277 | print_irq_inversion_bug(struct task_struct *curr, |
2278 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2279 | struct held_lock *this, int forwards, |
2280 | const char *irqclass) | |
2281 | { | |
dad3d743 SR |
2282 | struct lock_list *entry = other; |
2283 | struct lock_list *middle = NULL; | |
2284 | int depth; | |
2285 | ||
74c383f1 | 2286 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2287 | return 0; |
2288 | ||
b3fbab05 PM |
2289 | printk("\n"); |
2290 | printk("=========================================================\n"); | |
2291 | printk("[ INFO: possible irq lock inversion dependency detected ]\n"); | |
fbdc4b9a | 2292 | print_kernel_ident(); |
b3fbab05 | 2293 | printk("---------------------------------------------------------\n"); |
fbb9ce95 | 2294 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2295 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2296 | print_lock(this); |
2297 | if (forwards) | |
26575e28 | 2298 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2299 | else |
26575e28 | 2300 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2301 | print_lock_name(other->class); |
fbb9ce95 IM |
2302 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2303 | ||
2304 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2305 | |
2306 | /* Find a middle lock (if one exists) */ | |
2307 | depth = get_lock_depth(other); | |
2308 | do { | |
2309 | if (depth == 0 && (entry != root)) { | |
2310 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2311 | break; | |
2312 | } | |
2313 | middle = entry; | |
2314 | entry = get_lock_parent(entry); | |
2315 | depth--; | |
2316 | } while (entry && entry != root && (depth >= 0)); | |
2317 | if (forwards) | |
2318 | print_irq_lock_scenario(root, other, | |
2319 | middle ? middle->class : root->class, other->class); | |
2320 | else | |
2321 | print_irq_lock_scenario(other, root, | |
2322 | middle ? middle->class : other->class, root->class); | |
2323 | ||
fbb9ce95 IM |
2324 | lockdep_print_held_locks(curr); |
2325 | ||
24208ca7 ML |
2326 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2327 | if (!save_trace(&root->trace)) | |
2328 | return 0; | |
2329 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2330 | |
2331 | printk("\nstack backtrace:\n"); | |
2332 | dump_stack(); | |
2333 | ||
2334 | return 0; | |
2335 | } | |
2336 | ||
2337 | /* | |
2338 | * Prove that in the forwards-direction subgraph starting at <this> | |
2339 | * there is no lock matching <mask>: | |
2340 | */ | |
2341 | static int | |
2342 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2343 | enum lock_usage_bit bit, const char *irqclass) | |
2344 | { | |
2345 | int ret; | |
d7aaba14 ML |
2346 | struct lock_list root; |
2347 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2348 | |
d7aaba14 ML |
2349 | root.parent = NULL; |
2350 | root.class = hlock_class(this); | |
2351 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2352 | if (ret < 0) |
2353 | return print_bfs_bug(ret); | |
2354 | if (ret == 1) | |
2355 | return ret; | |
fbb9ce95 | 2356 | |
24208ca7 | 2357 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2358 | this, 1, irqclass); |
fbb9ce95 IM |
2359 | } |
2360 | ||
2361 | /* | |
2362 | * Prove that in the backwards-direction subgraph starting at <this> | |
2363 | * there is no lock matching <mask>: | |
2364 | */ | |
2365 | static int | |
2366 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2367 | enum lock_usage_bit bit, const char *irqclass) | |
2368 | { | |
2369 | int ret; | |
d7aaba14 ML |
2370 | struct lock_list root; |
2371 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2372 | |
d7aaba14 ML |
2373 | root.parent = NULL; |
2374 | root.class = hlock_class(this); | |
2375 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2376 | if (ret < 0) |
2377 | return print_bfs_bug(ret); | |
2378 | if (ret == 1) | |
2379 | return ret; | |
fbb9ce95 | 2380 | |
24208ca7 | 2381 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2382 | this, 0, irqclass); |
fbb9ce95 IM |
2383 | } |
2384 | ||
3117df04 | 2385 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2386 | { |
2387 | printk("irq event stamp: %u\n", curr->irq_events); | |
2388 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2389 | print_ip_sym(curr->hardirq_enable_ip); | |
2390 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2391 | print_ip_sym(curr->hardirq_disable_ip); | |
2392 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2393 | print_ip_sym(curr->softirq_enable_ip); | |
2394 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2395 | print_ip_sym(curr->softirq_disable_ip); | |
2396 | } | |
2397 | ||
cd95302d | 2398 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2399 | { |
8e18257d PZ |
2400 | #if HARDIRQ_VERBOSE |
2401 | return class_filter(class); | |
2402 | #endif | |
fbb9ce95 IM |
2403 | return 0; |
2404 | } | |
2405 | ||
cd95302d | 2406 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2407 | { |
8e18257d PZ |
2408 | #if SOFTIRQ_VERBOSE |
2409 | return class_filter(class); | |
2410 | #endif | |
2411 | return 0; | |
fbb9ce95 IM |
2412 | } |
2413 | ||
cd95302d | 2414 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2415 | { |
2416 | #if RECLAIM_VERBOSE | |
2417 | return class_filter(class); | |
2418 | #endif | |
2419 | return 0; | |
2420 | } | |
2421 | ||
fbb9ce95 IM |
2422 | #define STRICT_READ_CHECKS 1 |
2423 | ||
cd95302d PZ |
2424 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2425 | #define LOCKDEP_STATE(__STATE) \ | |
2426 | __STATE##_verbose, | |
2427 | #include "lockdep_states.h" | |
2428 | #undef LOCKDEP_STATE | |
2429 | }; | |
2430 | ||
2431 | static inline int state_verbose(enum lock_usage_bit bit, | |
2432 | struct lock_class *class) | |
2433 | { | |
2434 | return state_verbose_f[bit >> 2](class); | |
2435 | } | |
2436 | ||
42c50d54 PZ |
2437 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2438 | enum lock_usage_bit bit, const char *name); | |
2439 | ||
6a6904d3 | 2440 | static int |
1c21f14e PZ |
2441 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2442 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2443 | { |
f989209e | 2444 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2445 | int read = new_bit & 1; |
42c50d54 PZ |
2446 | int dir = new_bit & 2; |
2447 | ||
38aa2714 PZ |
2448 | /* |
2449 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2450 | * has ENABLED state, which would allow recursion deadlocks. | |
2451 | * | |
2452 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2453 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2454 | */ | |
42c50d54 PZ |
2455 | check_usage_f usage = dir ? |
2456 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2457 | |
38aa2714 PZ |
2458 | /* |
2459 | * Validate that this particular lock does not have conflicting | |
2460 | * usage states. | |
2461 | */ | |
6a6904d3 PZ |
2462 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2463 | return 0; | |
42c50d54 | 2464 | |
38aa2714 PZ |
2465 | /* |
2466 | * Validate that the lock dependencies don't have conflicting usage | |
2467 | * states. | |
2468 | */ | |
2469 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2470 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2471 | return 0; |
780e820b | 2472 | |
38aa2714 PZ |
2473 | /* |
2474 | * Check for read in write conflicts | |
2475 | */ | |
2476 | if (!read) { | |
2477 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2478 | return 0; | |
2479 | ||
2480 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2481 | !usage(curr, this, excl_bit + 1, |
2482 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2483 | return 0; |
2484 | } | |
780e820b | 2485 | |
cd95302d | 2486 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2487 | return 2; |
2488 | ||
2489 | return 1; | |
2490 | } | |
2491 | ||
cf40bd16 | 2492 | enum mark_type { |
36bfb9bb PZ |
2493 | #define LOCKDEP_STATE(__STATE) __STATE, |
2494 | #include "lockdep_states.h" | |
2495 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2496 | }; |
2497 | ||
fbb9ce95 IM |
2498 | /* |
2499 | * Mark all held locks with a usage bit: | |
2500 | */ | |
1d09daa5 | 2501 | static int |
cf40bd16 | 2502 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2503 | { |
2504 | enum lock_usage_bit usage_bit; | |
2505 | struct held_lock *hlock; | |
2506 | int i; | |
2507 | ||
2508 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2509 | hlock = curr->held_locks + i; | |
2510 | ||
cf2ad4d1 PZ |
2511 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2512 | if (hlock->read) | |
2513 | usage_bit += 1; /* READ */ | |
2514 | ||
2515 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2516 | |
70a0686a | 2517 | if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys) |
efbe2eee PZ |
2518 | continue; |
2519 | ||
4ff773bb | 2520 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2521 | return 0; |
2522 | } | |
2523 | ||
2524 | return 1; | |
2525 | } | |
2526 | ||
fbb9ce95 IM |
2527 | /* |
2528 | * Hardirqs will be enabled: | |
2529 | */ | |
dd4e5d3a | 2530 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2531 | { |
2532 | struct task_struct *curr = current; | |
fbb9ce95 | 2533 | |
fbb9ce95 IM |
2534 | /* we'll do an OFF -> ON transition: */ |
2535 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2536 | |
fbb9ce95 IM |
2537 | /* |
2538 | * We are going to turn hardirqs on, so set the | |
2539 | * usage bit for all held locks: | |
2540 | */ | |
cf40bd16 | 2541 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2542 | return; |
2543 | /* | |
2544 | * If we have softirqs enabled, then set the usage | |
2545 | * bit for all held locks. (disabled hardirqs prevented | |
2546 | * this bit from being set before) | |
2547 | */ | |
2548 | if (curr->softirqs_enabled) | |
cf40bd16 | 2549 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2550 | return; |
2551 | ||
8e18257d PZ |
2552 | curr->hardirq_enable_ip = ip; |
2553 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2554 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2555 | } |
dd4e5d3a PZ |
2556 | |
2557 | void trace_hardirqs_on_caller(unsigned long ip) | |
2558 | { | |
2559 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2560 | ||
2561 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2562 | return; | |
2563 | ||
7d36b26b PZ |
2564 | if (unlikely(current->hardirqs_enabled)) { |
2565 | /* | |
2566 | * Neither irq nor preemption are disabled here | |
2567 | * so this is racy by nature but losing one hit | |
2568 | * in a stat is not a big deal. | |
2569 | */ | |
2570 | __debug_atomic_inc(redundant_hardirqs_on); | |
2571 | return; | |
2572 | } | |
2573 | ||
0119fee4 PZ |
2574 | /* |
2575 | * We're enabling irqs and according to our state above irqs weren't | |
2576 | * already enabled, yet we find the hardware thinks they are in fact | |
2577 | * enabled.. someone messed up their IRQ state tracing. | |
2578 | */ | |
dd4e5d3a PZ |
2579 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2580 | return; | |
2581 | ||
0119fee4 PZ |
2582 | /* |
2583 | * See the fine text that goes along with this variable definition. | |
2584 | */ | |
7d36b26b PZ |
2585 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2586 | return; | |
2587 | ||
0119fee4 PZ |
2588 | /* |
2589 | * Can't allow enabling interrupts while in an interrupt handler, | |
2590 | * that's general bad form and such. Recursion, limited stack etc.. | |
2591 | */ | |
7d36b26b PZ |
2592 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2593 | return; | |
2594 | ||
dd4e5d3a PZ |
2595 | current->lockdep_recursion = 1; |
2596 | __trace_hardirqs_on_caller(ip); | |
2597 | current->lockdep_recursion = 0; | |
2598 | } | |
81d68a96 | 2599 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2600 | |
1d09daa5 | 2601 | void trace_hardirqs_on(void) |
81d68a96 SR |
2602 | { |
2603 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2604 | } | |
8e18257d PZ |
2605 | EXPORT_SYMBOL(trace_hardirqs_on); |
2606 | ||
2607 | /* | |
2608 | * Hardirqs were disabled: | |
2609 | */ | |
6afe40b4 | 2610 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2611 | { |
2612 | struct task_struct *curr = current; | |
2613 | ||
6afe40b4 | 2614 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2615 | |
8e18257d PZ |
2616 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2617 | return; | |
2618 | ||
0119fee4 PZ |
2619 | /* |
2620 | * So we're supposed to get called after you mask local IRQs, but for | |
2621 | * some reason the hardware doesn't quite think you did a proper job. | |
2622 | */ | |
8e18257d PZ |
2623 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2624 | return; | |
2625 | ||
2626 | if (curr->hardirqs_enabled) { | |
2627 | /* | |
2628 | * We have done an ON -> OFF transition: | |
2629 | */ | |
2630 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2631 | curr->hardirq_disable_ip = ip; |
8e18257d | 2632 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2633 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2634 | } else |
bd6d29c2 | 2635 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2636 | } |
81d68a96 | 2637 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2638 | |
1d09daa5 | 2639 | void trace_hardirqs_off(void) |
81d68a96 SR |
2640 | { |
2641 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2642 | } | |
8e18257d PZ |
2643 | EXPORT_SYMBOL(trace_hardirqs_off); |
2644 | ||
2645 | /* | |
2646 | * Softirqs will be enabled: | |
2647 | */ | |
2648 | void trace_softirqs_on(unsigned long ip) | |
2649 | { | |
2650 | struct task_struct *curr = current; | |
2651 | ||
dd4e5d3a | 2652 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2653 | return; |
2654 | ||
0119fee4 PZ |
2655 | /* |
2656 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2657 | * funny state and nesting things. | |
2658 | */ | |
8e18257d PZ |
2659 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2660 | return; | |
2661 | ||
2662 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2663 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2664 | return; |
2665 | } | |
2666 | ||
dd4e5d3a | 2667 | current->lockdep_recursion = 1; |
8e18257d PZ |
2668 | /* |
2669 | * We'll do an OFF -> ON transition: | |
2670 | */ | |
2671 | curr->softirqs_enabled = 1; | |
2672 | curr->softirq_enable_ip = ip; | |
2673 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2674 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2675 | /* |
2676 | * We are going to turn softirqs on, so set the | |
2677 | * usage bit for all held locks, if hardirqs are | |
2678 | * enabled too: | |
2679 | */ | |
2680 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2681 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2682 | current->lockdep_recursion = 0; |
8e18257d PZ |
2683 | } |
2684 | ||
2685 | /* | |
2686 | * Softirqs were disabled: | |
2687 | */ | |
2688 | void trace_softirqs_off(unsigned long ip) | |
2689 | { | |
2690 | struct task_struct *curr = current; | |
2691 | ||
dd4e5d3a | 2692 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2693 | return; |
2694 | ||
0119fee4 PZ |
2695 | /* |
2696 | * We fancy IRQs being disabled here, see softirq.c | |
2697 | */ | |
8e18257d PZ |
2698 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2699 | return; | |
2700 | ||
2701 | if (curr->softirqs_enabled) { | |
2702 | /* | |
2703 | * We have done an ON -> OFF transition: | |
2704 | */ | |
2705 | curr->softirqs_enabled = 0; | |
2706 | curr->softirq_disable_ip = ip; | |
2707 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2708 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
2709 | /* |
2710 | * Whoops, we wanted softirqs off, so why aren't they? | |
2711 | */ | |
8e18257d PZ |
2712 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2713 | } else | |
bd6d29c2 | 2714 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2715 | } |
2716 | ||
2f850181 | 2717 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2718 | { |
2719 | struct task_struct *curr = current; | |
2720 | ||
2721 | if (unlikely(!debug_locks)) | |
2722 | return; | |
2723 | ||
2724 | /* no reclaim without waiting on it */ | |
2725 | if (!(gfp_mask & __GFP_WAIT)) | |
2726 | return; | |
2727 | ||
2728 | /* this guy won't enter reclaim */ | |
2729 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2730 | return; | |
2731 | ||
2732 | /* We're only interested __GFP_FS allocations for now */ | |
2733 | if (!(gfp_mask & __GFP_FS)) | |
2734 | return; | |
2735 | ||
0119fee4 PZ |
2736 | /* |
2737 | * Oi! Can't be having __GFP_FS allocations with IRQs disabled. | |
2738 | */ | |
2f850181 | 2739 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2740 | return; |
2741 | ||
2742 | mark_held_locks(curr, RECLAIM_FS); | |
2743 | } | |
2744 | ||
2f850181 PZ |
2745 | static void check_flags(unsigned long flags); |
2746 | ||
2747 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2748 | { | |
2749 | unsigned long flags; | |
2750 | ||
2751 | if (unlikely(current->lockdep_recursion)) | |
2752 | return; | |
2753 | ||
2754 | raw_local_irq_save(flags); | |
2755 | check_flags(flags); | |
2756 | current->lockdep_recursion = 1; | |
2757 | __lockdep_trace_alloc(gfp_mask, flags); | |
2758 | current->lockdep_recursion = 0; | |
2759 | raw_local_irq_restore(flags); | |
2760 | } | |
2761 | ||
8e18257d PZ |
2762 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2763 | { | |
2764 | /* | |
2765 | * If non-trylock use in a hardirq or softirq context, then | |
2766 | * mark the lock as used in these contexts: | |
2767 | */ | |
2768 | if (!hlock->trylock) { | |
2769 | if (hlock->read) { | |
2770 | if (curr->hardirq_context) | |
2771 | if (!mark_lock(curr, hlock, | |
2772 | LOCK_USED_IN_HARDIRQ_READ)) | |
2773 | return 0; | |
2774 | if (curr->softirq_context) | |
2775 | if (!mark_lock(curr, hlock, | |
2776 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2777 | return 0; | |
2778 | } else { | |
2779 | if (curr->hardirq_context) | |
2780 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2781 | return 0; | |
2782 | if (curr->softirq_context) | |
2783 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2784 | return 0; | |
2785 | } | |
2786 | } | |
2787 | if (!hlock->hardirqs_off) { | |
2788 | if (hlock->read) { | |
2789 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2790 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2791 | return 0; |
2792 | if (curr->softirqs_enabled) | |
2793 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2794 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2795 | return 0; |
2796 | } else { | |
2797 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2798 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2799 | return 0; |
2800 | if (curr->softirqs_enabled) | |
2801 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2802 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2803 | return 0; |
2804 | } | |
2805 | } | |
2806 | ||
cf40bd16 NP |
2807 | /* |
2808 | * We reuse the irq context infrastructure more broadly as a general | |
2809 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2810 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2811 | * allocation). | |
2812 | */ | |
2813 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2814 | if (hlock->read) { | |
2815 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2816 | return 0; | |
2817 | } else { | |
2818 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2819 | return 0; | |
2820 | } | |
2821 | } | |
2822 | ||
8e18257d PZ |
2823 | return 1; |
2824 | } | |
2825 | ||
2826 | static int separate_irq_context(struct task_struct *curr, | |
2827 | struct held_lock *hlock) | |
2828 | { | |
2829 | unsigned int depth = curr->lockdep_depth; | |
2830 | ||
2831 | /* | |
2832 | * Keep track of points where we cross into an interrupt context: | |
2833 | */ | |
2834 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2835 | curr->softirq_context; | |
2836 | if (depth) { | |
2837 | struct held_lock *prev_hlock; | |
2838 | ||
2839 | prev_hlock = curr->held_locks + depth-1; | |
2840 | /* | |
2841 | * If we cross into another context, reset the | |
2842 | * hash key (this also prevents the checking and the | |
2843 | * adding of the dependency to 'prev'): | |
2844 | */ | |
2845 | if (prev_hlock->irq_context != hlock->irq_context) | |
2846 | return 1; | |
2847 | } | |
2848 | return 0; | |
fbb9ce95 IM |
2849 | } |
2850 | ||
0119fee4 | 2851 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 2852 | |
8e18257d PZ |
2853 | static inline |
2854 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2855 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2856 | { |
0119fee4 | 2857 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
2858 | return 1; |
2859 | } | |
fbb9ce95 | 2860 | |
8e18257d PZ |
2861 | static inline int mark_irqflags(struct task_struct *curr, |
2862 | struct held_lock *hlock) | |
2863 | { | |
2864 | return 1; | |
2865 | } | |
fbb9ce95 | 2866 | |
8e18257d PZ |
2867 | static inline int separate_irq_context(struct task_struct *curr, |
2868 | struct held_lock *hlock) | |
2869 | { | |
2870 | return 0; | |
fbb9ce95 IM |
2871 | } |
2872 | ||
868a23a8 PZ |
2873 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2874 | { | |
2875 | } | |
2876 | ||
0119fee4 | 2877 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
2878 | |
2879 | /* | |
8e18257d | 2880 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2881 | */ |
1d09daa5 | 2882 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2883 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2884 | { |
8e18257d | 2885 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2886 | |
2887 | /* | |
8e18257d PZ |
2888 | * If already set then do not dirty the cacheline, |
2889 | * nor do any checks: | |
fbb9ce95 | 2890 | */ |
f82b217e | 2891 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2892 | return 1; |
2893 | ||
2894 | if (!graph_lock()) | |
2895 | return 0; | |
fbb9ce95 | 2896 | /* |
25985edc | 2897 | * Make sure we didn't race: |
fbb9ce95 | 2898 | */ |
f82b217e | 2899 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2900 | graph_unlock(); |
2901 | return 1; | |
2902 | } | |
fbb9ce95 | 2903 | |
f82b217e | 2904 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2905 | |
f82b217e | 2906 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2907 | return 0; |
fbb9ce95 | 2908 | |
8e18257d | 2909 | switch (new_bit) { |
5346417e PZ |
2910 | #define LOCKDEP_STATE(__STATE) \ |
2911 | case LOCK_USED_IN_##__STATE: \ | |
2912 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2913 | case LOCK_ENABLED_##__STATE: \ | |
2914 | case LOCK_ENABLED_##__STATE##_READ: | |
2915 | #include "lockdep_states.h" | |
2916 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2917 | ret = mark_lock_irq(curr, this, new_bit); |
2918 | if (!ret) | |
2919 | return 0; | |
2920 | break; | |
2921 | case LOCK_USED: | |
bd6d29c2 | 2922 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
2923 | break; |
2924 | default: | |
2925 | if (!debug_locks_off_graph_unlock()) | |
2926 | return 0; | |
2927 | WARN_ON(1); | |
2928 | return 0; | |
2929 | } | |
fbb9ce95 | 2930 | |
8e18257d PZ |
2931 | graph_unlock(); |
2932 | ||
2933 | /* | |
2934 | * We must printk outside of the graph_lock: | |
2935 | */ | |
2936 | if (ret == 2) { | |
2937 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2938 | print_lock(this); | |
2939 | print_irqtrace_events(curr); | |
2940 | dump_stack(); | |
2941 | } | |
2942 | ||
2943 | return ret; | |
2944 | } | |
fbb9ce95 IM |
2945 | |
2946 | /* | |
2947 | * Initialize a lock instance's lock-class mapping info: | |
2948 | */ | |
2949 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2950 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2951 | { |
d3d03d4f YZ |
2952 | int i; |
2953 | ||
2954 | kmemcheck_mark_initialized(lock, sizeof(*lock)); | |
2955 | ||
2956 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) | |
2957 | lock->class_cache[i] = NULL; | |
62016250 | 2958 | |
c8a25005 PZ |
2959 | #ifdef CONFIG_LOCK_STAT |
2960 | lock->cpu = raw_smp_processor_id(); | |
2961 | #endif | |
2962 | ||
0119fee4 PZ |
2963 | /* |
2964 | * Can't be having no nameless bastards around this place! | |
2965 | */ | |
c8a25005 PZ |
2966 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
2967 | lock->name = "NULL"; | |
fbb9ce95 | 2968 | return; |
c8a25005 PZ |
2969 | } |
2970 | ||
2971 | lock->name = name; | |
fbb9ce95 | 2972 | |
0119fee4 PZ |
2973 | /* |
2974 | * No key, no joy, we need to hash something. | |
2975 | */ | |
fbb9ce95 IM |
2976 | if (DEBUG_LOCKS_WARN_ON(!key)) |
2977 | return; | |
fbb9ce95 IM |
2978 | /* |
2979 | * Sanity check, the lock-class key must be persistent: | |
2980 | */ | |
2981 | if (!static_obj(key)) { | |
2982 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
2983 | /* |
2984 | * What it says above ^^^^^, I suggest you read it. | |
2985 | */ | |
fbb9ce95 IM |
2986 | DEBUG_LOCKS_WARN_ON(1); |
2987 | return; | |
2988 | } | |
fbb9ce95 | 2989 | lock->key = key; |
c8a25005 PZ |
2990 | |
2991 | if (unlikely(!debug_locks)) | |
2992 | return; | |
2993 | ||
4dfbb9d8 PZ |
2994 | if (subclass) |
2995 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2996 | } |
fbb9ce95 IM |
2997 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2998 | ||
1704f47b PZ |
2999 | struct lock_class_key __lockdep_no_validate__; |
3000 | ||
d0945950 ML |
3001 | static int |
3002 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3003 | struct held_lock *hlock, | |
3004 | unsigned long ip) | |
3005 | { | |
3006 | if (!debug_locks_off()) | |
3007 | return 0; | |
3008 | if (debug_locks_silent) | |
3009 | return 0; | |
3010 | ||
3011 | printk("\n"); | |
3012 | printk("==================================\n"); | |
3013 | printk("[ BUG: Nested lock was not taken ]\n"); | |
3014 | print_kernel_ident(); | |
3015 | printk("----------------------------------\n"); | |
3016 | ||
3017 | printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); | |
3018 | print_lock(hlock); | |
3019 | ||
3020 | printk("\nbut this task is not holding:\n"); | |
3021 | printk("%s\n", hlock->nest_lock->name); | |
3022 | ||
3023 | printk("\nstack backtrace:\n"); | |
3024 | dump_stack(); | |
3025 | ||
3026 | printk("\nother info that might help us debug this:\n"); | |
3027 | lockdep_print_held_locks(curr); | |
3028 | ||
3029 | printk("\nstack backtrace:\n"); | |
3030 | dump_stack(); | |
3031 | ||
3032 | return 0; | |
3033 | } | |
3034 | ||
3035 | static int __lock_is_held(struct lockdep_map *lock); | |
3036 | ||
fbb9ce95 IM |
3037 | /* |
3038 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3039 | * We maintain the dependency maps and validate the locking attempt: | |
3040 | */ | |
3041 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3042 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
3043 | struct lockdep_map *nest_lock, unsigned long ip, |
3044 | int references) | |
fbb9ce95 IM |
3045 | { |
3046 | struct task_struct *curr = current; | |
d6d897ce | 3047 | struct lock_class *class = NULL; |
fbb9ce95 | 3048 | struct held_lock *hlock; |
fbb9ce95 IM |
3049 | unsigned int depth, id; |
3050 | int chain_head = 0; | |
bb97a91e | 3051 | int class_idx; |
fbb9ce95 IM |
3052 | u64 chain_key; |
3053 | ||
f20786ff PZ |
3054 | if (!prove_locking) |
3055 | check = 1; | |
3056 | ||
fbb9ce95 IM |
3057 | if (unlikely(!debug_locks)) |
3058 | return 0; | |
3059 | ||
0119fee4 PZ |
3060 | /* |
3061 | * Lockdep should run with IRQs disabled, otherwise we could | |
3062 | * get an interrupt which would want to take locks, which would | |
3063 | * end up in lockdep and have you got a head-ache already? | |
3064 | */ | |
fbb9ce95 IM |
3065 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3066 | return 0; | |
3067 | ||
1704f47b PZ |
3068 | if (lock->key == &__lockdep_no_validate__) |
3069 | check = 1; | |
3070 | ||
62016250 HM |
3071 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3072 | class = lock->class_cache[subclass]; | |
d6d897ce | 3073 | /* |
62016250 | 3074 | * Not cached? |
d6d897ce | 3075 | */ |
fbb9ce95 | 3076 | if (unlikely(!class)) { |
4dfbb9d8 | 3077 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3078 | if (!class) |
3079 | return 0; | |
3080 | } | |
bd6d29c2 | 3081 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3082 | if (very_verbose(class)) { |
3083 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3084 | if (class->name_version > 1) | |
3085 | printk("#%d", class->name_version); | |
3086 | printk("\n"); | |
3087 | dump_stack(); | |
3088 | } | |
3089 | ||
3090 | /* | |
3091 | * Add the lock to the list of currently held locks. | |
3092 | * (we dont increase the depth just yet, up until the | |
3093 | * dependency checks are done) | |
3094 | */ | |
3095 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3096 | /* |
3097 | * Ran out of static storage for our per-task lock stack again have we? | |
3098 | */ | |
fbb9ce95 IM |
3099 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3100 | return 0; | |
3101 | ||
bb97a91e PZ |
3102 | class_idx = class - lock_classes + 1; |
3103 | ||
3104 | if (depth) { | |
3105 | hlock = curr->held_locks + depth - 1; | |
3106 | if (hlock->class_idx == class_idx && nest_lock) { | |
3107 | if (hlock->references) | |
3108 | hlock->references++; | |
3109 | else | |
3110 | hlock->references = 2; | |
3111 | ||
3112 | return 1; | |
3113 | } | |
3114 | } | |
3115 | ||
fbb9ce95 | 3116 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3117 | /* |
3118 | * Plain impossible, we just registered it and checked it weren't no | |
3119 | * NULL like.. I bet this mushroom I ate was good! | |
3120 | */ | |
f82b217e DJ |
3121 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3122 | return 0; | |
bb97a91e | 3123 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3124 | hlock->acquire_ip = ip; |
3125 | hlock->instance = lock; | |
7531e2f3 | 3126 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
3127 | hlock->trylock = trylock; |
3128 | hlock->read = read; | |
3129 | hlock->check = check; | |
6951b12a | 3130 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3131 | hlock->references = references; |
f20786ff PZ |
3132 | #ifdef CONFIG_LOCK_STAT |
3133 | hlock->waittime_stamp = 0; | |
3365e779 | 3134 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3135 | #endif |
fbb9ce95 | 3136 | |
8e18257d PZ |
3137 | if (check == 2 && !mark_irqflags(curr, hlock)) |
3138 | return 0; | |
3139 | ||
fbb9ce95 | 3140 | /* mark it as used: */ |
4ff773bb | 3141 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3142 | return 0; |
8e18257d | 3143 | |
fbb9ce95 | 3144 | /* |
17aacfb9 | 3145 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3146 | * lock keys along the dependency chain. We save the hash value |
3147 | * at every step so that we can get the current hash easily | |
3148 | * after unlock. The chain hash is then used to cache dependency | |
3149 | * results. | |
3150 | * | |
3151 | * The 'key ID' is what is the most compact key value to drive | |
3152 | * the hash, not class->key. | |
3153 | */ | |
3154 | id = class - lock_classes; | |
0119fee4 PZ |
3155 | /* |
3156 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3157 | */ | |
fbb9ce95 IM |
3158 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
3159 | return 0; | |
3160 | ||
3161 | chain_key = curr->curr_chain_key; | |
3162 | if (!depth) { | |
0119fee4 PZ |
3163 | /* |
3164 | * How can we have a chain hash when we ain't got no keys?! | |
3165 | */ | |
fbb9ce95 IM |
3166 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3167 | return 0; | |
3168 | chain_head = 1; | |
3169 | } | |
3170 | ||
3171 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3172 | if (separate_irq_context(curr, hlock)) { |
3173 | chain_key = 0; | |
3174 | chain_head = 1; | |
fbb9ce95 | 3175 | } |
fbb9ce95 | 3176 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 3177 | |
d0945950 ML |
3178 | if (nest_lock && !__lock_is_held(nest_lock)) |
3179 | return print_lock_nested_lock_not_held(curr, hlock, ip); | |
3180 | ||
3aa416b0 | 3181 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3182 | return 0; |
381a2292 | 3183 | |
3aa416b0 | 3184 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3185 | curr->lockdep_depth++; |
3186 | check_chain_key(curr); | |
60e114d1 JP |
3187 | #ifdef CONFIG_DEBUG_LOCKDEP |
3188 | if (unlikely(!debug_locks)) | |
3189 | return 0; | |
3190 | #endif | |
fbb9ce95 IM |
3191 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3192 | debug_locks_off(); | |
c0540606 BG |
3193 | printk("BUG: MAX_LOCK_DEPTH too low, depth: %i max: %lu!\n", |
3194 | curr->lockdep_depth, MAX_LOCK_DEPTH); | |
fbb9ce95 | 3195 | printk("turning off the locking correctness validator.\n"); |
c0540606 BG |
3196 | |
3197 | lockdep_print_held_locks(current); | |
3198 | debug_show_all_locks(); | |
eedeeabd | 3199 | dump_stack(); |
c0540606 | 3200 | |
fbb9ce95 IM |
3201 | return 0; |
3202 | } | |
381a2292 | 3203 | |
fbb9ce95 IM |
3204 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3205 | max_lockdep_depth = curr->lockdep_depth; | |
3206 | ||
3207 | return 1; | |
3208 | } | |
3209 | ||
3210 | static int | |
f86f7554 | 3211 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3212 | unsigned long ip) |
3213 | { | |
3214 | if (!debug_locks_off()) | |
3215 | return 0; | |
3216 | if (debug_locks_silent) | |
3217 | return 0; | |
3218 | ||
b3fbab05 PM |
3219 | printk("\n"); |
3220 | printk("=====================================\n"); | |
3221 | printk("[ BUG: bad unlock balance detected! ]\n"); | |
fbdc4b9a | 3222 | print_kernel_ident(); |
b3fbab05 | 3223 | printk("-------------------------------------\n"); |
fbb9ce95 | 3224 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3225 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3226 | print_lockdep_cache(lock); |
3227 | printk(") at:\n"); | |
3228 | print_ip_sym(ip); | |
3229 | printk("but there are no more locks to release!\n"); | |
3230 | printk("\nother info that might help us debug this:\n"); | |
3231 | lockdep_print_held_locks(curr); | |
3232 | ||
3233 | printk("\nstack backtrace:\n"); | |
3234 | dump_stack(); | |
3235 | ||
3236 | return 0; | |
3237 | } | |
3238 | ||
3239 | /* | |
3240 | * Common debugging checks for both nested and non-nested unlock: | |
3241 | */ | |
3242 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
3243 | unsigned long ip) | |
3244 | { | |
3245 | if (unlikely(!debug_locks)) | |
3246 | return 0; | |
0119fee4 PZ |
3247 | /* |
3248 | * Lockdep should run with IRQs disabled, recursion, head-ache, etc.. | |
3249 | */ | |
fbb9ce95 IM |
3250 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3251 | return 0; | |
3252 | ||
3253 | if (curr->lockdep_depth <= 0) | |
f86f7554 | 3254 | return print_unlock_imbalance_bug(curr, lock, ip); |
fbb9ce95 IM |
3255 | |
3256 | return 1; | |
3257 | } | |
3258 | ||
bb97a91e PZ |
3259 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3260 | { | |
3261 | if (hlock->instance == lock) | |
3262 | return 1; | |
3263 | ||
3264 | if (hlock->references) { | |
62016250 | 3265 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3266 | |
3267 | if (!class) | |
3268 | class = look_up_lock_class(lock, 0); | |
3269 | ||
80e0401e PZ |
3270 | /* |
3271 | * If look_up_lock_class() failed to find a class, we're trying | |
3272 | * to test if we hold a lock that has never yet been acquired. | |
3273 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3274 | * holding it either, so report failure. | |
3275 | */ | |
3276 | if (!class) | |
bb97a91e PZ |
3277 | return 0; |
3278 | ||
0119fee4 PZ |
3279 | /* |
3280 | * References, but not a lock we're actually ref-counting? | |
3281 | * State got messed up, follow the sites that change ->references | |
3282 | * and try to make sense of it. | |
3283 | */ | |
bb97a91e PZ |
3284 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3285 | return 0; | |
3286 | ||
3287 | if (hlock->class_idx == class - lock_classes + 1) | |
3288 | return 1; | |
3289 | } | |
3290 | ||
3291 | return 0; | |
3292 | } | |
3293 | ||
64aa348e | 3294 | static int |
00ef9f73 PZ |
3295 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3296 | struct lock_class_key *key, unsigned int subclass, | |
3297 | unsigned long ip) | |
64aa348e PZ |
3298 | { |
3299 | struct task_struct *curr = current; | |
3300 | struct held_lock *hlock, *prev_hlock; | |
3301 | struct lock_class *class; | |
3302 | unsigned int depth; | |
3303 | int i; | |
3304 | ||
3305 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3306 | /* |
3307 | * This function is about (re)setting the class of a held lock, | |
3308 | * yet we're not actually holding any locks. Naughty user! | |
3309 | */ | |
64aa348e PZ |
3310 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3311 | return 0; | |
3312 | ||
3313 | prev_hlock = NULL; | |
3314 | for (i = depth-1; i >= 0; i--) { | |
3315 | hlock = curr->held_locks + i; | |
3316 | /* | |
3317 | * We must not cross into another context: | |
3318 | */ | |
3319 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3320 | break; | |
bb97a91e | 3321 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3322 | goto found_it; |
3323 | prev_hlock = hlock; | |
3324 | } | |
f86f7554 | 3325 | return print_unlock_imbalance_bug(curr, lock, ip); |
64aa348e PZ |
3326 | |
3327 | found_it: | |
00ef9f73 | 3328 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3329 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3330 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3331 | |
3332 | curr->lockdep_depth = i; | |
3333 | curr->curr_chain_key = hlock->prev_chain_key; | |
3334 | ||
3335 | for (; i < depth; i++) { | |
3336 | hlock = curr->held_locks + i; | |
3337 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3338 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3339 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3340 | hlock->nest_lock, hlock->acquire_ip, |
3341 | hlock->references)) | |
64aa348e PZ |
3342 | return 0; |
3343 | } | |
3344 | ||
0119fee4 PZ |
3345 | /* |
3346 | * I took it apart and put it back together again, except now I have | |
3347 | * these 'spare' parts.. where shall I put them. | |
3348 | */ | |
64aa348e PZ |
3349 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3350 | return 0; | |
3351 | return 1; | |
3352 | } | |
3353 | ||
fbb9ce95 IM |
3354 | /* |
3355 | * Remove the lock to the list of currently held locks in a | |
3356 | * potentially non-nested (out of order) manner. This is a | |
3357 | * relatively rare operation, as all the unlock APIs default | |
3358 | * to nested mode (which uses lock_release()): | |
3359 | */ | |
3360 | static int | |
3361 | lock_release_non_nested(struct task_struct *curr, | |
3362 | struct lockdep_map *lock, unsigned long ip) | |
3363 | { | |
3364 | struct held_lock *hlock, *prev_hlock; | |
3365 | unsigned int depth; | |
3366 | int i; | |
3367 | ||
3368 | /* | |
3369 | * Check whether the lock exists in the current stack | |
3370 | * of held locks: | |
3371 | */ | |
3372 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3373 | /* |
3374 | * So we're all set to release this lock.. wait what lock? We don't | |
3375 | * own any locks, you've been drinking again? | |
3376 | */ | |
fbb9ce95 IM |
3377 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3378 | return 0; | |
3379 | ||
3380 | prev_hlock = NULL; | |
3381 | for (i = depth-1; i >= 0; i--) { | |
3382 | hlock = curr->held_locks + i; | |
3383 | /* | |
3384 | * We must not cross into another context: | |
3385 | */ | |
3386 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3387 | break; | |
bb97a91e | 3388 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3389 | goto found_it; |
3390 | prev_hlock = hlock; | |
3391 | } | |
f86f7554 | 3392 | return print_unlock_imbalance_bug(curr, lock, ip); |
fbb9ce95 IM |
3393 | |
3394 | found_it: | |
bb97a91e PZ |
3395 | if (hlock->instance == lock) |
3396 | lock_release_holdtime(hlock); | |
3397 | ||
3398 | if (hlock->references) { | |
3399 | hlock->references--; | |
3400 | if (hlock->references) { | |
3401 | /* | |
3402 | * We had, and after removing one, still have | |
3403 | * references, the current lock stack is still | |
3404 | * valid. We're done! | |
3405 | */ | |
3406 | return 1; | |
3407 | } | |
3408 | } | |
f20786ff | 3409 | |
fbb9ce95 IM |
3410 | /* |
3411 | * We have the right lock to unlock, 'hlock' points to it. | |
3412 | * Now we remove it from the stack, and add back the other | |
3413 | * entries (if any), recalculating the hash along the way: | |
3414 | */ | |
bb97a91e | 3415 | |
fbb9ce95 IM |
3416 | curr->lockdep_depth = i; |
3417 | curr->curr_chain_key = hlock->prev_chain_key; | |
3418 | ||
3419 | for (i++; i < depth; i++) { | |
3420 | hlock = curr->held_locks + i; | |
3421 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3422 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3423 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3424 | hlock->nest_lock, hlock->acquire_ip, |
3425 | hlock->references)) | |
fbb9ce95 IM |
3426 | return 0; |
3427 | } | |
3428 | ||
0119fee4 PZ |
3429 | /* |
3430 | * We had N bottles of beer on the wall, we drank one, but now | |
3431 | * there's not N-1 bottles of beer left on the wall... | |
3432 | */ | |
fbb9ce95 IM |
3433 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3434 | return 0; | |
3435 | return 1; | |
3436 | } | |
3437 | ||
3438 | /* | |
3439 | * Remove the lock to the list of currently held locks - this gets | |
3440 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3441 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3442 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3443 | */ | |
3444 | static int lock_release_nested(struct task_struct *curr, | |
3445 | struct lockdep_map *lock, unsigned long ip) | |
3446 | { | |
3447 | struct held_lock *hlock; | |
3448 | unsigned int depth; | |
3449 | ||
3450 | /* | |
3451 | * Pop off the top of the lock stack: | |
3452 | */ | |
3453 | depth = curr->lockdep_depth - 1; | |
3454 | hlock = curr->held_locks + depth; | |
3455 | ||
3456 | /* | |
3457 | * Is the unlock non-nested: | |
3458 | */ | |
bb97a91e | 3459 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3460 | return lock_release_non_nested(curr, lock, ip); |
3461 | curr->lockdep_depth--; | |
3462 | ||
0119fee4 PZ |
3463 | /* |
3464 | * No more locks, but somehow we've got hash left over, who left it? | |
3465 | */ | |
fbb9ce95 IM |
3466 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) |
3467 | return 0; | |
3468 | ||
3469 | curr->curr_chain_key = hlock->prev_chain_key; | |
3470 | ||
f20786ff PZ |
3471 | lock_release_holdtime(hlock); |
3472 | ||
fbb9ce95 IM |
3473 | #ifdef CONFIG_DEBUG_LOCKDEP |
3474 | hlock->prev_chain_key = 0; | |
f82b217e | 3475 | hlock->class_idx = 0; |
fbb9ce95 IM |
3476 | hlock->acquire_ip = 0; |
3477 | hlock->irq_context = 0; | |
3478 | #endif | |
3479 | return 1; | |
3480 | } | |
3481 | ||
3482 | /* | |
3483 | * Remove the lock to the list of currently held locks - this gets | |
3484 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3485 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3486 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3487 | */ | |
3488 | static void | |
3489 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3490 | { | |
3491 | struct task_struct *curr = current; | |
3492 | ||
3493 | if (!check_unlock(curr, lock, ip)) | |
3494 | return; | |
3495 | ||
3496 | if (nested) { | |
3497 | if (!lock_release_nested(curr, lock, ip)) | |
3498 | return; | |
3499 | } else { | |
3500 | if (!lock_release_non_nested(curr, lock, ip)) | |
3501 | return; | |
3502 | } | |
3503 | ||
3504 | check_chain_key(curr); | |
3505 | } | |
3506 | ||
f607c668 PZ |
3507 | static int __lock_is_held(struct lockdep_map *lock) |
3508 | { | |
3509 | struct task_struct *curr = current; | |
3510 | int i; | |
3511 | ||
3512 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3513 | struct held_lock *hlock = curr->held_locks + i; |
3514 | ||
3515 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3516 | return 1; |
3517 | } | |
3518 | ||
3519 | return 0; | |
3520 | } | |
3521 | ||
fbb9ce95 IM |
3522 | /* |
3523 | * Check whether we follow the irq-flags state precisely: | |
3524 | */ | |
1d09daa5 | 3525 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3526 | { |
992860e9 IM |
3527 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3528 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3529 | if (!debug_locks) |
3530 | return; | |
3531 | ||
5f9fa8a6 IM |
3532 | if (irqs_disabled_flags(flags)) { |
3533 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3534 | printk("possible reason: unannotated irqs-off.\n"); | |
3535 | } | |
3536 | } else { | |
3537 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3538 | printk("possible reason: unannotated irqs-on.\n"); | |
3539 | } | |
3540 | } | |
fbb9ce95 IM |
3541 | |
3542 | /* | |
3543 | * We dont accurately track softirq state in e.g. | |
3544 | * hardirq contexts (such as on 4KSTACKS), so only | |
3545 | * check if not in hardirq contexts: | |
3546 | */ | |
3547 | if (!hardirq_count()) { | |
0119fee4 PZ |
3548 | if (softirq_count()) { |
3549 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3550 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3551 | } else { |
3552 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3553 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3554 | } |
fbb9ce95 IM |
3555 | } |
3556 | ||
3557 | if (!debug_locks) | |
3558 | print_irqtrace_events(current); | |
3559 | #endif | |
3560 | } | |
3561 | ||
00ef9f73 PZ |
3562 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3563 | struct lock_class_key *key, unsigned int subclass, | |
3564 | unsigned long ip) | |
64aa348e PZ |
3565 | { |
3566 | unsigned long flags; | |
3567 | ||
3568 | if (unlikely(current->lockdep_recursion)) | |
3569 | return; | |
3570 | ||
3571 | raw_local_irq_save(flags); | |
3572 | current->lockdep_recursion = 1; | |
3573 | check_flags(flags); | |
00ef9f73 | 3574 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3575 | check_chain_key(current); |
3576 | current->lockdep_recursion = 0; | |
3577 | raw_local_irq_restore(flags); | |
3578 | } | |
00ef9f73 | 3579 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3580 | |
fbb9ce95 IM |
3581 | /* |
3582 | * We are not always called with irqs disabled - do that here, | |
3583 | * and also avoid lockdep recursion: | |
3584 | */ | |
1d09daa5 | 3585 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3586 | int trylock, int read, int check, |
3587 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3588 | { |
3589 | unsigned long flags; | |
3590 | ||
3591 | if (unlikely(current->lockdep_recursion)) | |
3592 | return; | |
3593 | ||
3594 | raw_local_irq_save(flags); | |
3595 | check_flags(flags); | |
3596 | ||
3597 | current->lockdep_recursion = 1; | |
db2c4c77 | 3598 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3599 | __lock_acquire(lock, subclass, trylock, read, check, |
bb97a91e | 3600 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3601 | current->lockdep_recursion = 0; |
3602 | raw_local_irq_restore(flags); | |
3603 | } | |
fbb9ce95 IM |
3604 | EXPORT_SYMBOL_GPL(lock_acquire); |
3605 | ||
1d09daa5 | 3606 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3607 | unsigned long ip) |
fbb9ce95 IM |
3608 | { |
3609 | unsigned long flags; | |
3610 | ||
3611 | if (unlikely(current->lockdep_recursion)) | |
3612 | return; | |
3613 | ||
3614 | raw_local_irq_save(flags); | |
3615 | check_flags(flags); | |
3616 | current->lockdep_recursion = 1; | |
93135439 | 3617 | trace_lock_release(lock, ip); |
fbb9ce95 IM |
3618 | __lock_release(lock, nested, ip); |
3619 | current->lockdep_recursion = 0; | |
3620 | raw_local_irq_restore(flags); | |
3621 | } | |
fbb9ce95 IM |
3622 | EXPORT_SYMBOL_GPL(lock_release); |
3623 | ||
f607c668 PZ |
3624 | int lock_is_held(struct lockdep_map *lock) |
3625 | { | |
3626 | unsigned long flags; | |
3627 | int ret = 0; | |
3628 | ||
3629 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3630 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3631 | |
3632 | raw_local_irq_save(flags); | |
3633 | check_flags(flags); | |
3634 | ||
3635 | current->lockdep_recursion = 1; | |
3636 | ret = __lock_is_held(lock); | |
3637 | current->lockdep_recursion = 0; | |
3638 | raw_local_irq_restore(flags); | |
3639 | ||
3640 | return ret; | |
3641 | } | |
3642 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3643 | ||
cf40bd16 NP |
3644 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3645 | { | |
3646 | current->lockdep_reclaim_gfp = gfp_mask; | |
3647 | } | |
3648 | ||
3649 | void lockdep_clear_current_reclaim_state(void) | |
3650 | { | |
3651 | current->lockdep_reclaim_gfp = 0; | |
3652 | } | |
3653 | ||
f20786ff PZ |
3654 | #ifdef CONFIG_LOCK_STAT |
3655 | static int | |
3656 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3657 | unsigned long ip) | |
3658 | { | |
3659 | if (!debug_locks_off()) | |
3660 | return 0; | |
3661 | if (debug_locks_silent) | |
3662 | return 0; | |
3663 | ||
b3fbab05 PM |
3664 | printk("\n"); |
3665 | printk("=================================\n"); | |
3666 | printk("[ BUG: bad contention detected! ]\n"); | |
fbdc4b9a | 3667 | print_kernel_ident(); |
b3fbab05 | 3668 | printk("---------------------------------\n"); |
f20786ff | 3669 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3670 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3671 | print_lockdep_cache(lock); |
3672 | printk(") at:\n"); | |
3673 | print_ip_sym(ip); | |
3674 | printk("but there are no locks held!\n"); | |
3675 | printk("\nother info that might help us debug this:\n"); | |
3676 | lockdep_print_held_locks(curr); | |
3677 | ||
3678 | printk("\nstack backtrace:\n"); | |
3679 | dump_stack(); | |
3680 | ||
3681 | return 0; | |
3682 | } | |
3683 | ||
3684 | static void | |
3685 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3686 | { | |
3687 | struct task_struct *curr = current; | |
3688 | struct held_lock *hlock, *prev_hlock; | |
3689 | struct lock_class_stats *stats; | |
3690 | unsigned int depth; | |
c7e78cff | 3691 | int i, contention_point, contending_point; |
f20786ff PZ |
3692 | |
3693 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3694 | /* |
3695 | * Whee, we contended on this lock, except it seems we're not | |
3696 | * actually trying to acquire anything much at all.. | |
3697 | */ | |
f20786ff PZ |
3698 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3699 | return; | |
3700 | ||
3701 | prev_hlock = NULL; | |
3702 | for (i = depth-1; i >= 0; i--) { | |
3703 | hlock = curr->held_locks + i; | |
3704 | /* | |
3705 | * We must not cross into another context: | |
3706 | */ | |
3707 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3708 | break; | |
bb97a91e | 3709 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3710 | goto found_it; |
3711 | prev_hlock = hlock; | |
3712 | } | |
3713 | print_lock_contention_bug(curr, lock, ip); | |
3714 | return; | |
3715 | ||
3716 | found_it: | |
bb97a91e PZ |
3717 | if (hlock->instance != lock) |
3718 | return; | |
3719 | ||
3365e779 | 3720 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3721 | |
c7e78cff PZ |
3722 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3723 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3724 | lock->ip); | |
f20786ff | 3725 | |
f82b217e | 3726 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3727 | if (contention_point < LOCKSTAT_POINTS) |
3728 | stats->contention_point[contention_point]++; | |
3729 | if (contending_point < LOCKSTAT_POINTS) | |
3730 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3731 | if (lock->cpu != smp_processor_id()) |
3732 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3733 | put_lock_stats(stats); |
3734 | } | |
3735 | ||
3736 | static void | |
c7e78cff | 3737 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3738 | { |
3739 | struct task_struct *curr = current; | |
3740 | struct held_lock *hlock, *prev_hlock; | |
3741 | struct lock_class_stats *stats; | |
3742 | unsigned int depth; | |
3365e779 | 3743 | u64 now, waittime = 0; |
96645678 | 3744 | int i, cpu; |
f20786ff PZ |
3745 | |
3746 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3747 | /* |
3748 | * Yay, we acquired ownership of this lock we didn't try to | |
3749 | * acquire, how the heck did that happen? | |
3750 | */ | |
f20786ff PZ |
3751 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3752 | return; | |
3753 | ||
3754 | prev_hlock = NULL; | |
3755 | for (i = depth-1; i >= 0; i--) { | |
3756 | hlock = curr->held_locks + i; | |
3757 | /* | |
3758 | * We must not cross into another context: | |
3759 | */ | |
3760 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3761 | break; | |
bb97a91e | 3762 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3763 | goto found_it; |
3764 | prev_hlock = hlock; | |
3765 | } | |
3766 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3767 | return; | |
3768 | ||
3769 | found_it: | |
bb97a91e PZ |
3770 | if (hlock->instance != lock) |
3771 | return; | |
3772 | ||
96645678 PZ |
3773 | cpu = smp_processor_id(); |
3774 | if (hlock->waittime_stamp) { | |
3365e779 | 3775 | now = lockstat_clock(); |
96645678 PZ |
3776 | waittime = now - hlock->waittime_stamp; |
3777 | hlock->holdtime_stamp = now; | |
3778 | } | |
f20786ff | 3779 | |
883a2a31 | 3780 | trace_lock_acquired(lock, ip); |
2062501a | 3781 | |
f82b217e | 3782 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3783 | if (waittime) { |
3784 | if (hlock->read) | |
3785 | lock_time_inc(&stats->read_waittime, waittime); | |
3786 | else | |
3787 | lock_time_inc(&stats->write_waittime, waittime); | |
3788 | } | |
3789 | if (lock->cpu != cpu) | |
3790 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3791 | put_lock_stats(stats); |
96645678 PZ |
3792 | |
3793 | lock->cpu = cpu; | |
c7e78cff | 3794 | lock->ip = ip; |
f20786ff PZ |
3795 | } |
3796 | ||
3797 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3798 | { | |
3799 | unsigned long flags; | |
3800 | ||
3801 | if (unlikely(!lock_stat)) | |
3802 | return; | |
3803 | ||
3804 | if (unlikely(current->lockdep_recursion)) | |
3805 | return; | |
3806 | ||
3807 | raw_local_irq_save(flags); | |
3808 | check_flags(flags); | |
3809 | current->lockdep_recursion = 1; | |
db2c4c77 | 3810 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3811 | __lock_contended(lock, ip); |
3812 | current->lockdep_recursion = 0; | |
3813 | raw_local_irq_restore(flags); | |
3814 | } | |
3815 | EXPORT_SYMBOL_GPL(lock_contended); | |
3816 | ||
c7e78cff | 3817 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3818 | { |
3819 | unsigned long flags; | |
3820 | ||
3821 | if (unlikely(!lock_stat)) | |
3822 | return; | |
3823 | ||
3824 | if (unlikely(current->lockdep_recursion)) | |
3825 | return; | |
3826 | ||
3827 | raw_local_irq_save(flags); | |
3828 | check_flags(flags); | |
3829 | current->lockdep_recursion = 1; | |
c7e78cff | 3830 | __lock_acquired(lock, ip); |
f20786ff PZ |
3831 | current->lockdep_recursion = 0; |
3832 | raw_local_irq_restore(flags); | |
3833 | } | |
3834 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3835 | #endif | |
3836 | ||
fbb9ce95 IM |
3837 | /* |
3838 | * Used by the testsuite, sanitize the validator state | |
3839 | * after a simulated failure: | |
3840 | */ | |
3841 | ||
3842 | void lockdep_reset(void) | |
3843 | { | |
3844 | unsigned long flags; | |
23d95a03 | 3845 | int i; |
fbb9ce95 IM |
3846 | |
3847 | raw_local_irq_save(flags); | |
3848 | current->curr_chain_key = 0; | |
3849 | current->lockdep_depth = 0; | |
3850 | current->lockdep_recursion = 0; | |
3851 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3852 | nr_hardirq_chains = 0; | |
3853 | nr_softirq_chains = 0; | |
3854 | nr_process_chains = 0; | |
3855 | debug_locks = 1; | |
23d95a03 IM |
3856 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3857 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3858 | raw_local_irq_restore(flags); |
3859 | } | |
3860 | ||
3861 | static void zap_class(struct lock_class *class) | |
3862 | { | |
3863 | int i; | |
3864 | ||
3865 | /* | |
3866 | * Remove all dependencies this lock is | |
3867 | * involved in: | |
3868 | */ | |
3869 | for (i = 0; i < nr_list_entries; i++) { | |
3870 | if (list_entries[i].class == class) | |
3871 | list_del_rcu(&list_entries[i].entry); | |
3872 | } | |
3873 | /* | |
3874 | * Unhash the class and remove it from the all_lock_classes list: | |
3875 | */ | |
3876 | list_del_rcu(&class->hash_entry); | |
3877 | list_del_rcu(&class->lock_entry); | |
3878 | ||
8bfe0298 | 3879 | class->key = NULL; |
fbb9ce95 IM |
3880 | } |
3881 | ||
fabe874a | 3882 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3883 | { |
3884 | return addr >= start && addr < start + size; | |
3885 | } | |
3886 | ||
3887 | void lockdep_free_key_range(void *start, unsigned long size) | |
3888 | { | |
3889 | struct lock_class *class, *next; | |
3890 | struct list_head *head; | |
3891 | unsigned long flags; | |
3892 | int i; | |
5a26db5b | 3893 | int locked; |
fbb9ce95 IM |
3894 | |
3895 | raw_local_irq_save(flags); | |
5a26db5b | 3896 | locked = graph_lock(); |
fbb9ce95 IM |
3897 | |
3898 | /* | |
3899 | * Unhash all classes that were created by this module: | |
3900 | */ | |
3901 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3902 | head = classhash_table + i; | |
3903 | if (list_empty(head)) | |
3904 | continue; | |
fabe874a | 3905 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3906 | if (within(class->key, start, size)) |
3907 | zap_class(class); | |
fabe874a AV |
3908 | else if (within(class->name, start, size)) |
3909 | zap_class(class); | |
3910 | } | |
fbb9ce95 IM |
3911 | } |
3912 | ||
5a26db5b NP |
3913 | if (locked) |
3914 | graph_unlock(); | |
fbb9ce95 IM |
3915 | raw_local_irq_restore(flags); |
3916 | } | |
3917 | ||
3918 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3919 | { | |
d6d897ce | 3920 | struct lock_class *class, *next; |
fbb9ce95 IM |
3921 | struct list_head *head; |
3922 | unsigned long flags; | |
3923 | int i, j; | |
5a26db5b | 3924 | int locked; |
fbb9ce95 IM |
3925 | |
3926 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3927 | |
3928 | /* | |
d6d897ce IM |
3929 | * Remove all classes this lock might have: |
3930 | */ | |
3931 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3932 | /* | |
3933 | * If the class exists we look it up and zap it: | |
3934 | */ | |
3935 | class = look_up_lock_class(lock, j); | |
3936 | if (class) | |
3937 | zap_class(class); | |
3938 | } | |
3939 | /* | |
3940 | * Debug check: in the end all mapped classes should | |
3941 | * be gone. | |
fbb9ce95 | 3942 | */ |
5a26db5b | 3943 | locked = graph_lock(); |
fbb9ce95 IM |
3944 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3945 | head = classhash_table + i; | |
3946 | if (list_empty(head)) | |
3947 | continue; | |
3948 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
62016250 HM |
3949 | int match = 0; |
3950 | ||
3951 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
3952 | match |= class == lock->class_cache[j]; | |
3953 | ||
3954 | if (unlikely(match)) { | |
0119fee4 PZ |
3955 | if (debug_locks_off_graph_unlock()) { |
3956 | /* | |
3957 | * We all just reset everything, how did it match? | |
3958 | */ | |
74c383f1 | 3959 | WARN_ON(1); |
0119fee4 | 3960 | } |
d6d897ce | 3961 | goto out_restore; |
fbb9ce95 IM |
3962 | } |
3963 | } | |
3964 | } | |
5a26db5b NP |
3965 | if (locked) |
3966 | graph_unlock(); | |
d6d897ce IM |
3967 | |
3968 | out_restore: | |
fbb9ce95 IM |
3969 | raw_local_irq_restore(flags); |
3970 | } | |
3971 | ||
1499993c | 3972 | void lockdep_init(void) |
fbb9ce95 IM |
3973 | { |
3974 | int i; | |
3975 | ||
3976 | /* | |
3977 | * Some architectures have their own start_kernel() | |
3978 | * code which calls lockdep_init(), while we also | |
3979 | * call lockdep_init() from the start_kernel() itself, | |
3980 | * and we want to initialize the hashes only once: | |
3981 | */ | |
3982 | if (lockdep_initialized) | |
3983 | return; | |
3984 | ||
3985 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3986 | INIT_LIST_HEAD(classhash_table + i); | |
3987 | ||
3988 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3989 | INIT_LIST_HEAD(chainhash_table + i); | |
3990 | ||
3991 | lockdep_initialized = 1; | |
3992 | } | |
3993 | ||
3994 | void __init lockdep_info(void) | |
3995 | { | |
3996 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3997 | ||
b0788caf | 3998 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3999 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
4000 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 4001 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
4002 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
4003 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
4004 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
4005 | ||
4006 | printk(" memory used by lock dependency info: %lu kB\n", | |
4007 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
4008 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
4009 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
4010 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 4011 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 4012 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 4013 | + sizeof(struct circular_queue) |
4dd861d6 | 4014 | #endif |
90629209 | 4015 | ) / 1024 |
4dd861d6 | 4016 | ); |
fbb9ce95 IM |
4017 | |
4018 | printk(" per task-struct memory footprint: %lu bytes\n", | |
4019 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
4020 | ||
4021 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 | 4022 | if (lockdep_init_error) { |
81140acc ML |
4023 | printk("WARNING: lockdep init error! lock-%s was acquired" |
4024 | "before lockdep_init\n", lock_init_error); | |
c71063c9 JB |
4025 | printk("Call stack leading to lockdep invocation was:\n"); |
4026 | print_stack_trace(&lockdep_init_trace, 0); | |
4027 | } | |
fbb9ce95 IM |
4028 | #endif |
4029 | } | |
4030 | ||
fbb9ce95 IM |
4031 | static void |
4032 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 4033 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
4034 | { |
4035 | if (!debug_locks_off()) | |
4036 | return; | |
4037 | if (debug_locks_silent) | |
4038 | return; | |
4039 | ||
b3fbab05 PM |
4040 | printk("\n"); |
4041 | printk("=========================\n"); | |
4042 | printk("[ BUG: held lock freed! ]\n"); | |
fbdc4b9a | 4043 | print_kernel_ident(); |
b3fbab05 | 4044 | printk("-------------------------\n"); |
fbb9ce95 | 4045 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 4046 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 4047 | print_lock(hlock); |
fbb9ce95 IM |
4048 | lockdep_print_held_locks(curr); |
4049 | ||
4050 | printk("\nstack backtrace:\n"); | |
4051 | dump_stack(); | |
4052 | } | |
4053 | ||
54561783 ON |
4054 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4055 | const void* lock_from, unsigned long lock_len) | |
4056 | { | |
4057 | return lock_from + lock_len <= mem_from || | |
4058 | mem_from + mem_len <= lock_from; | |
4059 | } | |
4060 | ||
fbb9ce95 IM |
4061 | /* |
4062 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4063 | * is destroyed or reinitialized - this code checks whether there is | |
4064 | * any held lock in the memory range of <from> to <to>: | |
4065 | */ | |
4066 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4067 | { | |
fbb9ce95 IM |
4068 | struct task_struct *curr = current; |
4069 | struct held_lock *hlock; | |
4070 | unsigned long flags; | |
4071 | int i; | |
4072 | ||
4073 | if (unlikely(!debug_locks)) | |
4074 | return; | |
4075 | ||
4076 | local_irq_save(flags); | |
4077 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4078 | hlock = curr->held_locks + i; | |
4079 | ||
54561783 ON |
4080 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4081 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4082 | continue; |
4083 | ||
54561783 | 4084 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4085 | break; |
4086 | } | |
4087 | local_irq_restore(flags); | |
4088 | } | |
ed07536e | 4089 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
4090 | |
4091 | static void print_held_locks_bug(struct task_struct *curr) | |
4092 | { | |
4093 | if (!debug_locks_off()) | |
4094 | return; | |
4095 | if (debug_locks_silent) | |
4096 | return; | |
4097 | ||
b3fbab05 PM |
4098 | printk("\n"); |
4099 | printk("=====================================\n"); | |
4100 | printk("[ BUG: lock held at task exit time! ]\n"); | |
fbdc4b9a | 4101 | print_kernel_ident(); |
b3fbab05 | 4102 | printk("-------------------------------------\n"); |
fbb9ce95 | 4103 | printk("%s/%d is exiting with locks still held!\n", |
ba25f9dc | 4104 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
4105 | lockdep_print_held_locks(curr); |
4106 | ||
4107 | printk("\nstack backtrace:\n"); | |
4108 | dump_stack(); | |
4109 | } | |
4110 | ||
4111 | void debug_check_no_locks_held(struct task_struct *task) | |
4112 | { | |
4113 | if (unlikely(task->lockdep_depth > 0)) | |
4114 | print_held_locks_bug(task); | |
4115 | } | |
4116 | ||
4117 | void debug_show_all_locks(void) | |
4118 | { | |
4119 | struct task_struct *g, *p; | |
4120 | int count = 10; | |
4121 | int unlock = 1; | |
4122 | ||
9c35dd7f JP |
4123 | if (unlikely(!debug_locks)) { |
4124 | printk("INFO: lockdep is turned off.\n"); | |
4125 | return; | |
4126 | } | |
fbb9ce95 IM |
4127 | printk("\nShowing all locks held in the system:\n"); |
4128 | ||
4129 | /* | |
4130 | * Here we try to get the tasklist_lock as hard as possible, | |
4131 | * if not successful after 2 seconds we ignore it (but keep | |
4132 | * trying). This is to enable a debug printout even if a | |
4133 | * tasklist_lock-holding task deadlocks or crashes. | |
4134 | */ | |
4135 | retry: | |
4136 | if (!read_trylock(&tasklist_lock)) { | |
4137 | if (count == 10) | |
4138 | printk("hm, tasklist_lock locked, retrying... "); | |
4139 | if (count) { | |
4140 | count--; | |
4141 | printk(" #%d", 10-count); | |
4142 | mdelay(200); | |
4143 | goto retry; | |
4144 | } | |
4145 | printk(" ignoring it.\n"); | |
4146 | unlock = 0; | |
46fec7ac | 4147 | } else { |
4148 | if (count != 10) | |
4149 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 4150 | } |
fbb9ce95 IM |
4151 | |
4152 | do_each_thread(g, p) { | |
85684873 IM |
4153 | /* |
4154 | * It's not reliable to print a task's held locks | |
4155 | * if it's not sleeping (or if it's not the current | |
4156 | * task): | |
4157 | */ | |
4158 | if (p->state == TASK_RUNNING && p != current) | |
4159 | continue; | |
fbb9ce95 IM |
4160 | if (p->lockdep_depth) |
4161 | lockdep_print_held_locks(p); | |
4162 | if (!unlock) | |
4163 | if (read_trylock(&tasklist_lock)) | |
4164 | unlock = 1; | |
4165 | } while_each_thread(g, p); | |
4166 | ||
4167 | printk("\n"); | |
4168 | printk("=============================================\n\n"); | |
4169 | ||
4170 | if (unlock) | |
4171 | read_unlock(&tasklist_lock); | |
4172 | } | |
fbb9ce95 IM |
4173 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
4174 | ||
82a1fcb9 IM |
4175 | /* |
4176 | * Careful: only use this function if you are sure that | |
4177 | * the task cannot run in parallel! | |
4178 | */ | |
f1b499f0 | 4179 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4180 | { |
9c35dd7f JP |
4181 | if (unlikely(!debug_locks)) { |
4182 | printk("INFO: lockdep is turned off.\n"); | |
4183 | return; | |
4184 | } | |
fbb9ce95 IM |
4185 | lockdep_print_held_locks(task); |
4186 | } | |
fbb9ce95 | 4187 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
4188 | |
4189 | void lockdep_sys_exit(void) | |
4190 | { | |
4191 | struct task_struct *curr = current; | |
4192 | ||
4193 | if (unlikely(curr->lockdep_depth)) { | |
4194 | if (!debug_locks_off()) | |
4195 | return; | |
b3fbab05 PM |
4196 | printk("\n"); |
4197 | printk("================================================\n"); | |
4198 | printk("[ BUG: lock held when returning to user space! ]\n"); | |
fbdc4b9a | 4199 | print_kernel_ident(); |
b3fbab05 | 4200 | printk("------------------------------------------------\n"); |
b351d164 PZ |
4201 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4202 | curr->comm, curr->pid); | |
4203 | lockdep_print_held_locks(curr); | |
4204 | } | |
4205 | } | |
0632eb3d | 4206 | |
b3fbab05 | 4207 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4208 | { |
4209 | struct task_struct *curr = current; | |
4210 | ||
2b3fc35f | 4211 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4212 | if (!debug_locks_off()) |
4213 | return; | |
2b3fc35f LJ |
4214 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4215 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 PM |
4216 | printk("\n"); |
4217 | printk("===============================\n"); | |
4218 | printk("[ INFO: suspicious RCU usage. ]\n"); | |
fbdc4b9a | 4219 | print_kernel_ident(); |
b3fbab05 PM |
4220 | printk("-------------------------------\n"); |
4221 | printk("%s:%d %s!\n", file, line, s); | |
0632eb3d | 4222 | printk("\nother info that might help us debug this:\n\n"); |
c5fdcec9 PM |
4223 | printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n", |
4224 | !rcu_lockdep_current_cpu_online() | |
4225 | ? "RCU used illegally from offline CPU!\n" | |
4226 | : rcu_is_cpu_idle() | |
4227 | ? "RCU used illegally from idle CPU!\n" | |
4228 | : "", | |
4229 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
4230 | |
4231 | /* | |
4232 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
4233 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
4234 | * considers that CPU to be in an "extended quiescent state", | |
4235 | * which means that RCU will be completely ignoring that CPU. | |
4236 | * Therefore, rcu_read_lock() and friends have absolutely no | |
4237 | * effect on a CPU running in that state. In other words, even if | |
4238 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
4239 | * delete data structures out from under it. RCU really has no | |
4240 | * choice here: we need to keep an RCU-free window in idle where | |
4241 | * the CPU may possibly enter into low power mode. This way we can | |
4242 | * notice an extended quiescent state to other CPUs that started a grace | |
4243 | * period. Otherwise we would delay any grace period as long as we run | |
4244 | * in the idle task. | |
4245 | * | |
4246 | * So complain bitterly if someone does call rcu_read_lock(), | |
4247 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
4248 | */ | |
4249 | if (rcu_is_cpu_idle()) | |
4250 | printk("RCU used illegally from extended quiescent state!\n"); | |
4251 | ||
0632eb3d PM |
4252 | lockdep_print_held_locks(curr); |
4253 | printk("\nstack backtrace:\n"); | |
4254 | dump_stack(); | |
4255 | } | |
b3fbab05 | 4256 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |