Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
fbb9ce95 IM |
45 | |
46 | #include <asm/sections.h> | |
47 | ||
48 | #include "lockdep_internals.h" | |
49 | ||
f20786ff PZ |
50 | #ifdef CONFIG_PROVE_LOCKING |
51 | int prove_locking = 1; | |
52 | module_param(prove_locking, int, 0644); | |
53 | #else | |
54 | #define prove_locking 0 | |
55 | #endif | |
56 | ||
57 | #ifdef CONFIG_LOCK_STAT | |
58 | int lock_stat = 1; | |
59 | module_param(lock_stat, int, 0644); | |
60 | #else | |
61 | #define lock_stat 0 | |
62 | #endif | |
63 | ||
fbb9ce95 | 64 | /* |
74c383f1 IM |
65 | * lockdep_lock: protects the lockdep graph, the hashes and the |
66 | * class/list/hash allocators. | |
fbb9ce95 IM |
67 | * |
68 | * This is one of the rare exceptions where it's justified | |
69 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 70 | * code to recurse back into the lockdep code... |
fbb9ce95 | 71 | */ |
74c383f1 IM |
72 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
73 | ||
74 | static int graph_lock(void) | |
75 | { | |
76 | __raw_spin_lock(&lockdep_lock); | |
77 | /* | |
78 | * Make sure that if another CPU detected a bug while | |
79 | * walking the graph we dont change it (while the other | |
80 | * CPU is busy printing out stuff with the graph lock | |
81 | * dropped already) | |
82 | */ | |
83 | if (!debug_locks) { | |
84 | __raw_spin_unlock(&lockdep_lock); | |
85 | return 0; | |
86 | } | |
bb065afb SR |
87 | /* prevent any recursions within lockdep from causing deadlocks */ |
88 | current->lockdep_recursion++; | |
74c383f1 IM |
89 | return 1; |
90 | } | |
91 | ||
92 | static inline int graph_unlock(void) | |
93 | { | |
381a2292 JP |
94 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
95 | return DEBUG_LOCKS_WARN_ON(1); | |
96 | ||
bb065afb | 97 | current->lockdep_recursion--; |
74c383f1 IM |
98 | __raw_spin_unlock(&lockdep_lock); |
99 | return 0; | |
100 | } | |
101 | ||
102 | /* | |
103 | * Turn lock debugging off and return with 0 if it was off already, | |
104 | * and also release the graph lock: | |
105 | */ | |
106 | static inline int debug_locks_off_graph_unlock(void) | |
107 | { | |
108 | int ret = debug_locks_off(); | |
109 | ||
110 | __raw_spin_unlock(&lockdep_lock); | |
111 | ||
112 | return ret; | |
113 | } | |
fbb9ce95 IM |
114 | |
115 | static int lockdep_initialized; | |
116 | ||
117 | unsigned long nr_list_entries; | |
118 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; | |
119 | ||
fbb9ce95 IM |
120 | /* |
121 | * All data structures here are protected by the global debug_lock. | |
122 | * | |
123 | * Mutex key structs only get allocated, once during bootup, and never | |
124 | * get freed - this significantly simplifies the debugging code. | |
125 | */ | |
126 | unsigned long nr_lock_classes; | |
127 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
128 | ||
f82b217e DJ |
129 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
130 | { | |
131 | if (!hlock->class_idx) { | |
132 | DEBUG_LOCKS_WARN_ON(1); | |
133 | return NULL; | |
134 | } | |
135 | return lock_classes + hlock->class_idx - 1; | |
136 | } | |
137 | ||
f20786ff PZ |
138 | #ifdef CONFIG_LOCK_STAT |
139 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); | |
140 | ||
c7e78cff | 141 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
142 | { |
143 | int i; | |
144 | ||
c7e78cff PZ |
145 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
146 | if (points[i] == 0) { | |
147 | points[i] = ip; | |
f20786ff PZ |
148 | break; |
149 | } | |
c7e78cff | 150 | if (points[i] == ip) |
f20786ff PZ |
151 | break; |
152 | } | |
153 | ||
154 | return i; | |
155 | } | |
156 | ||
157 | static void lock_time_inc(struct lock_time *lt, s64 time) | |
158 | { | |
159 | if (time > lt->max) | |
160 | lt->max = time; | |
161 | ||
162 | if (time < lt->min || !lt->min) | |
163 | lt->min = time; | |
164 | ||
165 | lt->total += time; | |
166 | lt->nr++; | |
167 | } | |
168 | ||
c46261de PZ |
169 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
170 | { | |
171 | dst->min += src->min; | |
172 | dst->max += src->max; | |
173 | dst->total += src->total; | |
174 | dst->nr += src->nr; | |
175 | } | |
176 | ||
177 | struct lock_class_stats lock_stats(struct lock_class *class) | |
178 | { | |
179 | struct lock_class_stats stats; | |
180 | int cpu, i; | |
181 | ||
182 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
183 | for_each_possible_cpu(cpu) { | |
184 | struct lock_class_stats *pcs = | |
185 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
186 | ||
187 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
188 | stats.contention_point[i] += pcs->contention_point[i]; | |
189 | ||
c7e78cff PZ |
190 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
191 | stats.contending_point[i] += pcs->contending_point[i]; | |
192 | ||
c46261de PZ |
193 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
194 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
195 | ||
196 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
197 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
198 | |
199 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
200 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
201 | } |
202 | ||
203 | return stats; | |
204 | } | |
205 | ||
206 | void clear_lock_stats(struct lock_class *class) | |
207 | { | |
208 | int cpu; | |
209 | ||
210 | for_each_possible_cpu(cpu) { | |
211 | struct lock_class_stats *cpu_stats = | |
212 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
213 | ||
214 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
215 | } | |
216 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 217 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
218 | } |
219 | ||
f20786ff PZ |
220 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
221 | { | |
222 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
223 | } | |
224 | ||
225 | static void put_lock_stats(struct lock_class_stats *stats) | |
226 | { | |
227 | put_cpu_var(lock_stats); | |
228 | } | |
229 | ||
230 | static void lock_release_holdtime(struct held_lock *hlock) | |
231 | { | |
232 | struct lock_class_stats *stats; | |
233 | s64 holdtime; | |
234 | ||
235 | if (!lock_stat) | |
236 | return; | |
237 | ||
238 | holdtime = sched_clock() - hlock->holdtime_stamp; | |
239 | ||
f82b217e | 240 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
241 | if (hlock->read) |
242 | lock_time_inc(&stats->read_holdtime, holdtime); | |
243 | else | |
244 | lock_time_inc(&stats->write_holdtime, holdtime); | |
245 | put_lock_stats(stats); | |
246 | } | |
247 | #else | |
248 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
249 | { | |
250 | } | |
251 | #endif | |
252 | ||
fbb9ce95 IM |
253 | /* |
254 | * We keep a global list of all lock classes. The list only grows, | |
255 | * never shrinks. The list is only accessed with the lockdep | |
256 | * spinlock lock held. | |
257 | */ | |
258 | LIST_HEAD(all_lock_classes); | |
259 | ||
260 | /* | |
261 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
262 | */ | |
263 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
264 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 265 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
266 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
267 | ||
268 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
269 | ||
fbb9ce95 IM |
270 | /* |
271 | * We put the lock dependency chains into a hash-table as well, to cache | |
272 | * their existence: | |
273 | */ | |
274 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
275 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 276 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
277 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
278 | ||
279 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
280 | ||
281 | /* | |
282 | * The hash key of the lock dependency chains is a hash itself too: | |
283 | * it's a hash of all locks taken up to that lock, including that lock. | |
284 | * It's a 64-bit hash, because it's important for the keys to be | |
285 | * unique. | |
286 | */ | |
287 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
288 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
289 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
290 | (key2)) |
291 | ||
1d09daa5 | 292 | void lockdep_off(void) |
fbb9ce95 IM |
293 | { |
294 | current->lockdep_recursion++; | |
295 | } | |
fbb9ce95 IM |
296 | EXPORT_SYMBOL(lockdep_off); |
297 | ||
1d09daa5 | 298 | void lockdep_on(void) |
fbb9ce95 IM |
299 | { |
300 | current->lockdep_recursion--; | |
301 | } | |
fbb9ce95 IM |
302 | EXPORT_SYMBOL(lockdep_on); |
303 | ||
fbb9ce95 IM |
304 | /* |
305 | * Debugging switches: | |
306 | */ | |
307 | ||
308 | #define VERBOSE 0 | |
33e94e96 | 309 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
310 | |
311 | #if VERBOSE | |
312 | # define HARDIRQ_VERBOSE 1 | |
313 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 314 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
315 | #else |
316 | # define HARDIRQ_VERBOSE 0 | |
317 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 318 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
319 | #endif |
320 | ||
cf40bd16 | 321 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
322 | /* |
323 | * Quick filtering for interesting events: | |
324 | */ | |
325 | static int class_filter(struct lock_class *class) | |
326 | { | |
f9829cce AK |
327 | #if 0 |
328 | /* Example */ | |
fbb9ce95 | 329 | if (class->name_version == 1 && |
f9829cce | 330 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
331 | return 1; |
332 | if (class->name_version == 1 && | |
f9829cce | 333 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 334 | return 1; |
f9829cce | 335 | #endif |
a6640897 IM |
336 | /* Filter everything else. 1 would be to allow everything else */ |
337 | return 0; | |
fbb9ce95 IM |
338 | } |
339 | #endif | |
340 | ||
341 | static int verbose(struct lock_class *class) | |
342 | { | |
343 | #if VERBOSE | |
344 | return class_filter(class); | |
345 | #endif | |
346 | return 0; | |
347 | } | |
348 | ||
fbb9ce95 IM |
349 | /* |
350 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 351 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
352 | */ |
353 | unsigned long nr_stack_trace_entries; | |
354 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
355 | ||
356 | static int save_trace(struct stack_trace *trace) | |
357 | { | |
358 | trace->nr_entries = 0; | |
359 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
360 | trace->entries = stack_trace + nr_stack_trace_entries; | |
361 | ||
5a1b3999 | 362 | trace->skip = 3; |
5a1b3999 | 363 | |
ab1b6f03 | 364 | save_stack_trace(trace); |
fbb9ce95 IM |
365 | |
366 | trace->max_entries = trace->nr_entries; | |
367 | ||
368 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
369 | |
370 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
371 | if (!debug_locks_off_graph_unlock()) |
372 | return 0; | |
373 | ||
374 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
375 | printk("turning off the locking correctness validator.\n"); | |
376 | dump_stack(); | |
377 | ||
fbb9ce95 IM |
378 | return 0; |
379 | } | |
380 | ||
381 | return 1; | |
382 | } | |
383 | ||
384 | unsigned int nr_hardirq_chains; | |
385 | unsigned int nr_softirq_chains; | |
386 | unsigned int nr_process_chains; | |
387 | unsigned int max_lockdep_depth; | |
388 | unsigned int max_recursion_depth; | |
389 | ||
419ca3f1 DM |
390 | static unsigned int lockdep_dependency_gen_id; |
391 | ||
392 | static bool lockdep_dependency_visit(struct lock_class *source, | |
393 | unsigned int depth) | |
394 | { | |
395 | if (!depth) | |
396 | lockdep_dependency_gen_id++; | |
397 | if (source->dep_gen_id == lockdep_dependency_gen_id) | |
398 | return true; | |
399 | source->dep_gen_id = lockdep_dependency_gen_id; | |
400 | return false; | |
401 | } | |
402 | ||
fbb9ce95 IM |
403 | #ifdef CONFIG_DEBUG_LOCKDEP |
404 | /* | |
405 | * We cannot printk in early bootup code. Not even early_printk() | |
406 | * might work. So we mark any initialization errors and printk | |
407 | * about it later on, in lockdep_info(). | |
408 | */ | |
409 | static int lockdep_init_error; | |
c71063c9 JB |
410 | static unsigned long lockdep_init_trace_data[20]; |
411 | static struct stack_trace lockdep_init_trace = { | |
412 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
413 | .entries = lockdep_init_trace_data, | |
414 | }; | |
fbb9ce95 IM |
415 | |
416 | /* | |
417 | * Various lockdep statistics: | |
418 | */ | |
419 | atomic_t chain_lookup_hits; | |
420 | atomic_t chain_lookup_misses; | |
421 | atomic_t hardirqs_on_events; | |
422 | atomic_t hardirqs_off_events; | |
423 | atomic_t redundant_hardirqs_on; | |
424 | atomic_t redundant_hardirqs_off; | |
425 | atomic_t softirqs_on_events; | |
426 | atomic_t softirqs_off_events; | |
427 | atomic_t redundant_softirqs_on; | |
428 | atomic_t redundant_softirqs_off; | |
429 | atomic_t nr_unused_locks; | |
430 | atomic_t nr_cyclic_checks; | |
431 | atomic_t nr_cyclic_check_recursions; | |
432 | atomic_t nr_find_usage_forwards_checks; | |
433 | atomic_t nr_find_usage_forwards_recursions; | |
434 | atomic_t nr_find_usage_backwards_checks; | |
435 | atomic_t nr_find_usage_backwards_recursions; | |
436 | # define debug_atomic_inc(ptr) atomic_inc(ptr) | |
437 | # define debug_atomic_dec(ptr) atomic_dec(ptr) | |
438 | # define debug_atomic_read(ptr) atomic_read(ptr) | |
439 | #else | |
440 | # define debug_atomic_inc(ptr) do { } while (0) | |
441 | # define debug_atomic_dec(ptr) do { } while (0) | |
442 | # define debug_atomic_read(ptr) 0 | |
443 | #endif | |
444 | ||
445 | /* | |
446 | * Locking printouts: | |
447 | */ | |
448 | ||
fabe9c42 | 449 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
450 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
451 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
452 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
453 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 454 | |
fbb9ce95 IM |
455 | static const char *usage_str[] = |
456 | { | |
fabe9c42 PZ |
457 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
458 | #include "lockdep_states.h" | |
459 | #undef LOCKDEP_STATE | |
460 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
461 | }; |
462 | ||
463 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
464 | { | |
ffb45122 | 465 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
466 | } |
467 | ||
3ff176ca | 468 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 469 | { |
3ff176ca PZ |
470 | return 1UL << bit; |
471 | } | |
fbb9ce95 | 472 | |
3ff176ca PZ |
473 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
474 | { | |
475 | char c = '.'; | |
476 | ||
477 | if (class->usage_mask & lock_flag(bit + 2)) | |
478 | c = '+'; | |
479 | if (class->usage_mask & lock_flag(bit)) { | |
480 | c = '-'; | |
481 | if (class->usage_mask & lock_flag(bit + 2)) | |
482 | c = '?'; | |
fbb9ce95 IM |
483 | } |
484 | ||
3ff176ca PZ |
485 | return c; |
486 | } | |
cf40bd16 | 487 | |
f510b233 | 488 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 489 | { |
f510b233 | 490 | int i = 0; |
cf40bd16 | 491 | |
f510b233 PZ |
492 | #define LOCKDEP_STATE(__STATE) \ |
493 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
494 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
495 | #include "lockdep_states.h" | |
496 | #undef LOCKDEP_STATE | |
497 | ||
498 | usage[i] = '\0'; | |
fbb9ce95 IM |
499 | } |
500 | ||
501 | static void print_lock_name(struct lock_class *class) | |
502 | { | |
f510b233 | 503 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
504 | const char *name; |
505 | ||
f510b233 | 506 | get_usage_chars(class, usage); |
fbb9ce95 IM |
507 | |
508 | name = class->name; | |
509 | if (!name) { | |
510 | name = __get_key_name(class->key, str); | |
511 | printk(" (%s", name); | |
512 | } else { | |
513 | printk(" (%s", name); | |
514 | if (class->name_version > 1) | |
515 | printk("#%d", class->name_version); | |
516 | if (class->subclass) | |
517 | printk("/%d", class->subclass); | |
518 | } | |
f510b233 | 519 | printk("){%s}", usage); |
fbb9ce95 IM |
520 | } |
521 | ||
522 | static void print_lockdep_cache(struct lockdep_map *lock) | |
523 | { | |
524 | const char *name; | |
9281acea | 525 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
526 | |
527 | name = lock->name; | |
528 | if (!name) | |
529 | name = __get_key_name(lock->key->subkeys, str); | |
530 | ||
531 | printk("%s", name); | |
532 | } | |
533 | ||
534 | static void print_lock(struct held_lock *hlock) | |
535 | { | |
f82b217e | 536 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
537 | printk(", at: "); |
538 | print_ip_sym(hlock->acquire_ip); | |
539 | } | |
540 | ||
541 | static void lockdep_print_held_locks(struct task_struct *curr) | |
542 | { | |
543 | int i, depth = curr->lockdep_depth; | |
544 | ||
545 | if (!depth) { | |
ba25f9dc | 546 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
547 | return; |
548 | } | |
549 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 550 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
551 | |
552 | for (i = 0; i < depth; i++) { | |
553 | printk(" #%d: ", i); | |
554 | print_lock(curr->held_locks + i); | |
555 | } | |
556 | } | |
fbb9ce95 IM |
557 | |
558 | static void print_lock_class_header(struct lock_class *class, int depth) | |
559 | { | |
560 | int bit; | |
561 | ||
f9829cce | 562 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
563 | print_lock_name(class); |
564 | printk(" ops: %lu", class->ops); | |
565 | printk(" {\n"); | |
566 | ||
567 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
568 | if (class->usage_mask & (1 << bit)) { | |
569 | int len = depth; | |
570 | ||
f9829cce | 571 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
572 | len += printk(" at:\n"); |
573 | print_stack_trace(class->usage_traces + bit, len); | |
574 | } | |
575 | } | |
f9829cce | 576 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 577 | |
f9829cce | 578 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
579 | print_ip_sym((unsigned long)class->key); |
580 | } | |
581 | ||
582 | /* | |
583 | * printk all lock dependencies starting at <entry>: | |
584 | */ | |
7807fafa IM |
585 | static void __used |
586 | print_lock_dependencies(struct lock_class *class, int depth) | |
fbb9ce95 IM |
587 | { |
588 | struct lock_list *entry; | |
589 | ||
419ca3f1 DM |
590 | if (lockdep_dependency_visit(class, depth)) |
591 | return; | |
592 | ||
fbb9ce95 IM |
593 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) |
594 | return; | |
595 | ||
596 | print_lock_class_header(class, depth); | |
597 | ||
598 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
599 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
600 | return; | |
601 | ||
fbb9ce95 IM |
602 | print_lock_dependencies(entry->class, depth + 1); |
603 | ||
f9829cce | 604 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
605 | print_stack_trace(&entry->trace, 2); |
606 | printk("\n"); | |
607 | } | |
608 | } | |
609 | ||
8e18257d PZ |
610 | static void print_kernel_version(void) |
611 | { | |
612 | printk("%s %.*s\n", init_utsname()->release, | |
613 | (int)strcspn(init_utsname()->version, " "), | |
614 | init_utsname()->version); | |
615 | } | |
616 | ||
617 | static int very_verbose(struct lock_class *class) | |
618 | { | |
619 | #if VERY_VERBOSE | |
620 | return class_filter(class); | |
621 | #endif | |
622 | return 0; | |
623 | } | |
624 | ||
fbb9ce95 | 625 | /* |
8e18257d | 626 | * Is this the address of a static object: |
fbb9ce95 | 627 | */ |
8e18257d | 628 | static int static_obj(void *obj) |
fbb9ce95 | 629 | { |
8e18257d PZ |
630 | unsigned long start = (unsigned long) &_stext, |
631 | end = (unsigned long) &_end, | |
632 | addr = (unsigned long) obj; | |
633 | #ifdef CONFIG_SMP | |
634 | int i; | |
635 | #endif | |
636 | ||
fbb9ce95 | 637 | /* |
8e18257d | 638 | * static variable? |
fbb9ce95 | 639 | */ |
8e18257d PZ |
640 | if ((addr >= start) && (addr < end)) |
641 | return 1; | |
fbb9ce95 | 642 | |
8e18257d | 643 | #ifdef CONFIG_SMP |
fbb9ce95 | 644 | /* |
8e18257d | 645 | * percpu var? |
fbb9ce95 | 646 | */ |
8e18257d PZ |
647 | for_each_possible_cpu(i) { |
648 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
649 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
650 | + per_cpu_offset(i); | |
fbb9ce95 | 651 | |
8e18257d PZ |
652 | if ((addr >= start) && (addr < end)) |
653 | return 1; | |
654 | } | |
ca58abcb | 655 | #endif |
fbb9ce95 | 656 | |
8e18257d PZ |
657 | /* |
658 | * module var? | |
659 | */ | |
660 | return is_module_address(addr); | |
99de055a DJ |
661 | } |
662 | ||
fbb9ce95 | 663 | /* |
8e18257d PZ |
664 | * To make lock name printouts unique, we calculate a unique |
665 | * class->name_version generation counter: | |
fbb9ce95 | 666 | */ |
8e18257d | 667 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 668 | { |
8e18257d PZ |
669 | struct lock_class *class; |
670 | int count = 0; | |
fbb9ce95 | 671 | |
8e18257d | 672 | if (!new_class->name) |
fbb9ce95 IM |
673 | return 0; |
674 | ||
8e18257d PZ |
675 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
676 | if (new_class->key - new_class->subclass == class->key) | |
677 | return class->name_version; | |
678 | if (class->name && !strcmp(class->name, new_class->name)) | |
679 | count = max(count, class->name_version); | |
680 | } | |
fbb9ce95 | 681 | |
8e18257d | 682 | return count + 1; |
fbb9ce95 IM |
683 | } |
684 | ||
8e18257d PZ |
685 | /* |
686 | * Register a lock's class in the hash-table, if the class is not present | |
687 | * yet. Otherwise we look it up. We cache the result in the lock object | |
688 | * itself, so actual lookup of the hash should be once per lock object. | |
689 | */ | |
690 | static inline struct lock_class * | |
691 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 692 | { |
8e18257d PZ |
693 | struct lockdep_subclass_key *key; |
694 | struct list_head *hash_head; | |
695 | struct lock_class *class; | |
fbb9ce95 | 696 | |
8e18257d PZ |
697 | #ifdef CONFIG_DEBUG_LOCKDEP |
698 | /* | |
699 | * If the architecture calls into lockdep before initializing | |
700 | * the hashes then we'll warn about it later. (we cannot printk | |
701 | * right now) | |
702 | */ | |
703 | if (unlikely(!lockdep_initialized)) { | |
704 | lockdep_init(); | |
705 | lockdep_init_error = 1; | |
c71063c9 | 706 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
707 | } |
708 | #endif | |
fbb9ce95 | 709 | |
8e18257d PZ |
710 | /* |
711 | * Static locks do not have their class-keys yet - for them the key | |
712 | * is the lock object itself: | |
713 | */ | |
714 | if (unlikely(!lock->key)) | |
715 | lock->key = (void *)lock; | |
fbb9ce95 | 716 | |
8e18257d PZ |
717 | /* |
718 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
719 | * lock_class_key variable is passed in through the mutex_init() | |
720 | * (or spin_lock_init()) call - which acts as the key. For static | |
721 | * locks we use the lock object itself as the key. | |
722 | */ | |
4b32d0a4 PZ |
723 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
724 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 725 | |
8e18257d | 726 | key = lock->key->subkeys + subclass; |
ca268c69 | 727 | |
8e18257d | 728 | hash_head = classhashentry(key); |
74c383f1 | 729 | |
8e18257d PZ |
730 | /* |
731 | * We can walk the hash lockfree, because the hash only | |
732 | * grows, and we are careful when adding entries to the end: | |
733 | */ | |
4b32d0a4 PZ |
734 | list_for_each_entry(class, hash_head, hash_entry) { |
735 | if (class->key == key) { | |
736 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 737 | return class; |
4b32d0a4 PZ |
738 | } |
739 | } | |
fbb9ce95 | 740 | |
8e18257d | 741 | return NULL; |
fbb9ce95 IM |
742 | } |
743 | ||
744 | /* | |
8e18257d PZ |
745 | * Register a lock's class in the hash-table, if the class is not present |
746 | * yet. Otherwise we look it up. We cache the result in the lock object | |
747 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 748 | */ |
8e18257d PZ |
749 | static inline struct lock_class * |
750 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 751 | { |
8e18257d PZ |
752 | struct lockdep_subclass_key *key; |
753 | struct list_head *hash_head; | |
754 | struct lock_class *class; | |
755 | unsigned long flags; | |
756 | ||
757 | class = look_up_lock_class(lock, subclass); | |
758 | if (likely(class)) | |
759 | return class; | |
760 | ||
761 | /* | |
762 | * Debug-check: all keys must be persistent! | |
763 | */ | |
764 | if (!static_obj(lock->key)) { | |
765 | debug_locks_off(); | |
766 | printk("INFO: trying to register non-static key.\n"); | |
767 | printk("the code is fine but needs lockdep annotation.\n"); | |
768 | printk("turning off the locking correctness validator.\n"); | |
769 | dump_stack(); | |
770 | ||
771 | return NULL; | |
772 | } | |
773 | ||
774 | key = lock->key->subkeys + subclass; | |
775 | hash_head = classhashentry(key); | |
776 | ||
777 | raw_local_irq_save(flags); | |
778 | if (!graph_lock()) { | |
779 | raw_local_irq_restore(flags); | |
780 | return NULL; | |
781 | } | |
782 | /* | |
783 | * We have to do the hash-walk again, to avoid races | |
784 | * with another CPU: | |
785 | */ | |
786 | list_for_each_entry(class, hash_head, hash_entry) | |
787 | if (class->key == key) | |
788 | goto out_unlock_set; | |
789 | /* | |
790 | * Allocate a new key from the static array, and add it to | |
791 | * the hash: | |
792 | */ | |
793 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
794 | if (!debug_locks_off_graph_unlock()) { | |
795 | raw_local_irq_restore(flags); | |
796 | return NULL; | |
797 | } | |
798 | raw_local_irq_restore(flags); | |
799 | ||
800 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
801 | printk("turning off the locking correctness validator.\n"); | |
802 | return NULL; | |
803 | } | |
804 | class = lock_classes + nr_lock_classes++; | |
805 | debug_atomic_inc(&nr_unused_locks); | |
806 | class->key = key; | |
807 | class->name = lock->name; | |
808 | class->subclass = subclass; | |
809 | INIT_LIST_HEAD(&class->lock_entry); | |
810 | INIT_LIST_HEAD(&class->locks_before); | |
811 | INIT_LIST_HEAD(&class->locks_after); | |
812 | class->name_version = count_matching_names(class); | |
813 | /* | |
814 | * We use RCU's safe list-add method to make | |
815 | * parallel walking of the hash-list safe: | |
816 | */ | |
817 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
818 | /* |
819 | * Add it to the global list of classes: | |
820 | */ | |
821 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
822 | |
823 | if (verbose(class)) { | |
824 | graph_unlock(); | |
825 | raw_local_irq_restore(flags); | |
826 | ||
827 | printk("\nnew class %p: %s", class->key, class->name); | |
828 | if (class->name_version > 1) | |
829 | printk("#%d", class->name_version); | |
830 | printk("\n"); | |
831 | dump_stack(); | |
832 | ||
833 | raw_local_irq_save(flags); | |
834 | if (!graph_lock()) { | |
835 | raw_local_irq_restore(flags); | |
836 | return NULL; | |
837 | } | |
838 | } | |
839 | out_unlock_set: | |
840 | graph_unlock(); | |
841 | raw_local_irq_restore(flags); | |
842 | ||
843 | if (!subclass || force) | |
844 | lock->class_cache = class; | |
845 | ||
846 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
847 | return NULL; | |
848 | ||
849 | return class; | |
850 | } | |
851 | ||
852 | #ifdef CONFIG_PROVE_LOCKING | |
853 | /* | |
854 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
855 | * with NULL on failure) | |
856 | */ | |
857 | static struct lock_list *alloc_list_entry(void) | |
858 | { | |
859 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
860 | if (!debug_locks_off_graph_unlock()) | |
861 | return NULL; | |
862 | ||
863 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
864 | printk("turning off the locking correctness validator.\n"); | |
865 | return NULL; | |
866 | } | |
867 | return list_entries + nr_list_entries++; | |
868 | } | |
869 | ||
870 | /* | |
871 | * Add a new dependency to the head of the list: | |
872 | */ | |
873 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
874 | struct list_head *head, unsigned long ip, int distance) | |
875 | { | |
876 | struct lock_list *entry; | |
877 | /* | |
878 | * Lock not present yet - get a new dependency struct and | |
879 | * add it to the list: | |
880 | */ | |
881 | entry = alloc_list_entry(); | |
882 | if (!entry) | |
883 | return 0; | |
884 | ||
8e18257d PZ |
885 | if (!save_trace(&entry->trace)) |
886 | return 0; | |
887 | ||
74870172 ZY |
888 | entry->class = this; |
889 | entry->distance = distance; | |
8e18257d PZ |
890 | /* |
891 | * Since we never remove from the dependency list, the list can | |
892 | * be walked lockless by other CPUs, it's only allocation | |
893 | * that must be protected by the spinlock. But this also means | |
894 | * we must make new entries visible only once writes to the | |
895 | * entry become visible - hence the RCU op: | |
896 | */ | |
897 | list_add_tail_rcu(&entry->entry, head); | |
898 | ||
899 | return 1; | |
900 | } | |
901 | ||
902 | /* | |
903 | * Recursive, forwards-direction lock-dependency checking, used for | |
904 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
905 | * checking. | |
906 | * | |
907 | * (to keep the stackframe of the recursive functions small we | |
908 | * use these global variables, and we also mark various helper | |
909 | * functions as noinline.) | |
910 | */ | |
911 | static struct held_lock *check_source, *check_target; | |
912 | ||
913 | /* | |
914 | * Print a dependency chain entry (this is only done when a deadlock | |
915 | * has been detected): | |
916 | */ | |
917 | static noinline int | |
918 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |
919 | { | |
920 | if (debug_locks_silent) | |
921 | return 0; | |
922 | printk("\n-> #%u", depth); | |
923 | print_lock_name(target->class); | |
924 | printk(":\n"); | |
925 | print_stack_trace(&target->trace, 6); | |
926 | ||
927 | return 0; | |
928 | } | |
929 | ||
930 | /* | |
931 | * When a circular dependency is detected, print the | |
932 | * header first: | |
933 | */ | |
934 | static noinline int | |
935 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) | |
936 | { | |
937 | struct task_struct *curr = current; | |
938 | ||
939 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
940 | return 0; | |
941 | ||
942 | printk("\n=======================================================\n"); | |
943 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
944 | print_kernel_version(); | |
945 | printk( "-------------------------------------------------------\n"); | |
946 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 947 | curr->comm, task_pid_nr(curr)); |
8e18257d PZ |
948 | print_lock(check_source); |
949 | printk("\nbut task is already holding lock:\n"); | |
950 | print_lock(check_target); | |
951 | printk("\nwhich lock already depends on the new lock.\n\n"); | |
952 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
953 | ||
954 | print_circular_bug_entry(entry, depth); | |
955 | ||
956 | return 0; | |
957 | } | |
958 | ||
959 | static noinline int print_circular_bug_tail(void) | |
960 | { | |
961 | struct task_struct *curr = current; | |
962 | struct lock_list this; | |
963 | ||
964 | if (debug_locks_silent) | |
965 | return 0; | |
966 | ||
f82b217e | 967 | this.class = hlock_class(check_source); |
8e18257d PZ |
968 | if (!save_trace(&this.trace)) |
969 | return 0; | |
970 | ||
971 | print_circular_bug_entry(&this, 0); | |
972 | ||
973 | printk("\nother info that might help us debug this:\n\n"); | |
974 | lockdep_print_held_locks(curr); | |
975 | ||
976 | printk("\nstack backtrace:\n"); | |
977 | dump_stack(); | |
978 | ||
979 | return 0; | |
980 | } | |
981 | ||
982 | #define RECURSION_LIMIT 40 | |
983 | ||
984 | static int noinline print_infinite_recursion_bug(void) | |
985 | { | |
986 | if (!debug_locks_off_graph_unlock()) | |
987 | return 0; | |
988 | ||
989 | WARN_ON(1); | |
990 | ||
991 | return 0; | |
992 | } | |
993 | ||
419ca3f1 DM |
994 | unsigned long __lockdep_count_forward_deps(struct lock_class *class, |
995 | unsigned int depth) | |
996 | { | |
997 | struct lock_list *entry; | |
998 | unsigned long ret = 1; | |
999 | ||
1000 | if (lockdep_dependency_visit(class, depth)) | |
1001 | return 0; | |
1002 | ||
1003 | /* | |
1004 | * Recurse this class's dependency list: | |
1005 | */ | |
1006 | list_for_each_entry(entry, &class->locks_after, entry) | |
1007 | ret += __lockdep_count_forward_deps(entry->class, depth + 1); | |
1008 | ||
1009 | return ret; | |
1010 | } | |
1011 | ||
1012 | unsigned long lockdep_count_forward_deps(struct lock_class *class) | |
1013 | { | |
1014 | unsigned long ret, flags; | |
1015 | ||
1016 | local_irq_save(flags); | |
1017 | __raw_spin_lock(&lockdep_lock); | |
1018 | ret = __lockdep_count_forward_deps(class, 0); | |
1019 | __raw_spin_unlock(&lockdep_lock); | |
1020 | local_irq_restore(flags); | |
1021 | ||
1022 | return ret; | |
1023 | } | |
1024 | ||
1025 | unsigned long __lockdep_count_backward_deps(struct lock_class *class, | |
1026 | unsigned int depth) | |
1027 | { | |
1028 | struct lock_list *entry; | |
1029 | unsigned long ret = 1; | |
1030 | ||
1031 | if (lockdep_dependency_visit(class, depth)) | |
1032 | return 0; | |
1033 | /* | |
1034 | * Recurse this class's dependency list: | |
1035 | */ | |
1036 | list_for_each_entry(entry, &class->locks_before, entry) | |
1037 | ret += __lockdep_count_backward_deps(entry->class, depth + 1); | |
1038 | ||
1039 | return ret; | |
1040 | } | |
1041 | ||
1042 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1043 | { | |
1044 | unsigned long ret, flags; | |
1045 | ||
1046 | local_irq_save(flags); | |
1047 | __raw_spin_lock(&lockdep_lock); | |
1048 | ret = __lockdep_count_backward_deps(class, 0); | |
1049 | __raw_spin_unlock(&lockdep_lock); | |
1050 | local_irq_restore(flags); | |
1051 | ||
1052 | return ret; | |
1053 | } | |
1054 | ||
8e18257d PZ |
1055 | /* |
1056 | * Prove that the dependency graph starting at <entry> can not | |
1057 | * lead to <target>. Print an error and return 0 if it does. | |
1058 | */ | |
1059 | static noinline int | |
1060 | check_noncircular(struct lock_class *source, unsigned int depth) | |
1061 | { | |
1062 | struct lock_list *entry; | |
1063 | ||
419ca3f1 DM |
1064 | if (lockdep_dependency_visit(source, depth)) |
1065 | return 1; | |
1066 | ||
8e18257d PZ |
1067 | debug_atomic_inc(&nr_cyclic_check_recursions); |
1068 | if (depth > max_recursion_depth) | |
fbb9ce95 | 1069 | max_recursion_depth = depth; |
ca268c69 | 1070 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1071 | return print_infinite_recursion_bug(); |
1072 | /* | |
1073 | * Check this lock's dependency list: | |
1074 | */ | |
1075 | list_for_each_entry(entry, &source->locks_after, entry) { | |
f82b217e | 1076 | if (entry->class == hlock_class(check_target)) |
fbb9ce95 IM |
1077 | return print_circular_bug_header(entry, depth+1); |
1078 | debug_atomic_inc(&nr_cyclic_checks); | |
1079 | if (!check_noncircular(entry->class, depth+1)) | |
1080 | return print_circular_bug_entry(entry, depth+1); | |
1081 | } | |
1082 | return 1; | |
1083 | } | |
1084 | ||
81d68a96 | 1085 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1086 | /* |
1087 | * Forwards and backwards subgraph searching, for the purposes of | |
1088 | * proving that two subgraphs can be connected by a new dependency | |
1089 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1090 | */ | |
1091 | static enum lock_usage_bit find_usage_bit; | |
1092 | static struct lock_class *forwards_match, *backwards_match; | |
1093 | ||
1094 | /* | |
1095 | * Find a node in the forwards-direction dependency sub-graph starting | |
1096 | * at <source> that matches <find_usage_bit>. | |
1097 | * | |
1098 | * Return 2 if such a node exists in the subgraph, and put that node | |
1099 | * into <forwards_match>. | |
1100 | * | |
1101 | * Return 1 otherwise and keep <forwards_match> unchanged. | |
1102 | * Return 0 on error. | |
1103 | */ | |
1104 | static noinline int | |
1105 | find_usage_forwards(struct lock_class *source, unsigned int depth) | |
1106 | { | |
1107 | struct lock_list *entry; | |
1108 | int ret; | |
1109 | ||
419ca3f1 DM |
1110 | if (lockdep_dependency_visit(source, depth)) |
1111 | return 1; | |
1112 | ||
fbb9ce95 IM |
1113 | if (depth > max_recursion_depth) |
1114 | max_recursion_depth = depth; | |
ca268c69 | 1115 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1116 | return print_infinite_recursion_bug(); |
1117 | ||
1118 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
1119 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1120 | forwards_match = source; | |
1121 | return 2; | |
1122 | } | |
1123 | ||
1124 | /* | |
1125 | * Check this lock's dependency list: | |
1126 | */ | |
1127 | list_for_each_entry(entry, &source->locks_after, entry) { | |
1128 | debug_atomic_inc(&nr_find_usage_forwards_recursions); | |
1129 | ret = find_usage_forwards(entry->class, depth+1); | |
1130 | if (ret == 2 || ret == 0) | |
1131 | return ret; | |
1132 | } | |
1133 | return 1; | |
1134 | } | |
1135 | ||
1136 | /* | |
1137 | * Find a node in the backwards-direction dependency sub-graph starting | |
1138 | * at <source> that matches <find_usage_bit>. | |
1139 | * | |
1140 | * Return 2 if such a node exists in the subgraph, and put that node | |
1141 | * into <backwards_match>. | |
1142 | * | |
1143 | * Return 1 otherwise and keep <backwards_match> unchanged. | |
1144 | * Return 0 on error. | |
1145 | */ | |
1d09daa5 | 1146 | static noinline int |
fbb9ce95 IM |
1147 | find_usage_backwards(struct lock_class *source, unsigned int depth) |
1148 | { | |
1149 | struct lock_list *entry; | |
1150 | int ret; | |
1151 | ||
419ca3f1 DM |
1152 | if (lockdep_dependency_visit(source, depth)) |
1153 | return 1; | |
1154 | ||
381a2292 JP |
1155 | if (!__raw_spin_is_locked(&lockdep_lock)) |
1156 | return DEBUG_LOCKS_WARN_ON(1); | |
1157 | ||
fbb9ce95 IM |
1158 | if (depth > max_recursion_depth) |
1159 | max_recursion_depth = depth; | |
ca268c69 | 1160 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1161 | return print_infinite_recursion_bug(); |
1162 | ||
1163 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
1164 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1165 | backwards_match = source; | |
1166 | return 2; | |
1167 | } | |
1168 | ||
f82b217e DJ |
1169 | if (!source && debug_locks_off_graph_unlock()) { |
1170 | WARN_ON(1); | |
1171 | return 0; | |
1172 | } | |
1173 | ||
fbb9ce95 IM |
1174 | /* |
1175 | * Check this lock's dependency list: | |
1176 | */ | |
1177 | list_for_each_entry(entry, &source->locks_before, entry) { | |
1178 | debug_atomic_inc(&nr_find_usage_backwards_recursions); | |
1179 | ret = find_usage_backwards(entry->class, depth+1); | |
1180 | if (ret == 2 || ret == 0) | |
1181 | return ret; | |
1182 | } | |
1183 | return 1; | |
1184 | } | |
1185 | ||
1186 | static int | |
1187 | print_bad_irq_dependency(struct task_struct *curr, | |
1188 | struct held_lock *prev, | |
1189 | struct held_lock *next, | |
1190 | enum lock_usage_bit bit1, | |
1191 | enum lock_usage_bit bit2, | |
1192 | const char *irqclass) | |
1193 | { | |
74c383f1 | 1194 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1195 | return 0; |
1196 | ||
1197 | printk("\n======================================================\n"); | |
1198 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1199 | irqclass, irqclass); | |
99de055a | 1200 | print_kernel_version(); |
fbb9ce95 IM |
1201 | printk( "------------------------------------------------------\n"); |
1202 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1203 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1204 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1205 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1206 | curr->hardirqs_enabled, | |
1207 | curr->softirqs_enabled); | |
1208 | print_lock(next); | |
1209 | ||
1210 | printk("\nand this task is already holding:\n"); | |
1211 | print_lock(prev); | |
1212 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1213 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1214 | printk(" ->"); |
f82b217e | 1215 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1216 | printk("\n"); |
1217 | ||
1218 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1219 | irqclass); | |
1220 | print_lock_name(backwards_match); | |
1221 | printk("\n... which became %s-irq-safe at:\n", irqclass); | |
1222 | ||
1223 | print_stack_trace(backwards_match->usage_traces + bit1, 1); | |
1224 | ||
1225 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
1226 | print_lock_name(forwards_match); | |
1227 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); | |
1228 | printk("..."); | |
1229 | ||
1230 | print_stack_trace(forwards_match->usage_traces + bit2, 1); | |
1231 | ||
1232 | printk("\nother info that might help us debug this:\n\n"); | |
1233 | lockdep_print_held_locks(curr); | |
1234 | ||
1235 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); | |
1236 | print_lock_dependencies(backwards_match, 0); | |
1237 | ||
1238 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); | |
1239 | print_lock_dependencies(forwards_match, 0); | |
1240 | ||
1241 | printk("\nstack backtrace:\n"); | |
1242 | dump_stack(); | |
1243 | ||
1244 | return 0; | |
1245 | } | |
1246 | ||
1247 | static int | |
1248 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1249 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1250 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1251 | { | |
1252 | int ret; | |
1253 | ||
1254 | find_usage_bit = bit_backwards; | |
1255 | /* fills in <backwards_match> */ | |
f82b217e | 1256 | ret = find_usage_backwards(hlock_class(prev), 0); |
fbb9ce95 IM |
1257 | if (!ret || ret == 1) |
1258 | return ret; | |
1259 | ||
1260 | find_usage_bit = bit_forwards; | |
f82b217e | 1261 | ret = find_usage_forwards(hlock_class(next), 0); |
fbb9ce95 IM |
1262 | if (!ret || ret == 1) |
1263 | return ret; | |
1264 | /* ret == 2 */ | |
1265 | return print_bad_irq_dependency(curr, prev, next, | |
1266 | bit_backwards, bit_forwards, irqclass); | |
1267 | } | |
1268 | ||
4f367d8a PZ |
1269 | static const char *state_names[] = { |
1270 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1271 | __stringify(__STATE), |
4f367d8a PZ |
1272 | #include "lockdep_states.h" |
1273 | #undef LOCKDEP_STATE | |
1274 | }; | |
1275 | ||
1276 | static const char *state_rnames[] = { | |
1277 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1278 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1279 | #include "lockdep_states.h" |
1280 | #undef LOCKDEP_STATE | |
1281 | }; | |
1282 | ||
1283 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1284 | { |
4f367d8a PZ |
1285 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1286 | } | |
8e18257d | 1287 | |
4f367d8a PZ |
1288 | static int exclusive_bit(int new_bit) |
1289 | { | |
8e18257d | 1290 | /* |
4f367d8a PZ |
1291 | * USED_IN |
1292 | * USED_IN_READ | |
1293 | * ENABLED | |
1294 | * ENABLED_READ | |
1295 | * | |
1296 | * bit 0 - write/read | |
1297 | * bit 1 - used_in/enabled | |
1298 | * bit 2+ state | |
8e18257d | 1299 | */ |
4f367d8a PZ |
1300 | |
1301 | int state = new_bit & ~3; | |
1302 | int dir = new_bit & 2; | |
8e18257d PZ |
1303 | |
1304 | /* | |
4f367d8a | 1305 | * keep state, bit flip the direction and strip read. |
8e18257d | 1306 | */ |
4f367d8a PZ |
1307 | return state | (dir ^ 2); |
1308 | } | |
1309 | ||
1310 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1311 | struct held_lock *next, enum lock_usage_bit bit) | |
1312 | { | |
8e18257d | 1313 | /* |
4f367d8a PZ |
1314 | * Prove that the new dependency does not connect a hardirq-safe |
1315 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1316 | * the backwards-subgraph starting at <prev>, and the |
1317 | * forwards-subgraph starting at <next>: | |
1318 | */ | |
4f367d8a PZ |
1319 | if (!check_usage(curr, prev, next, bit, |
1320 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1321 | return 0; |
1322 | ||
4f367d8a PZ |
1323 | bit++; /* _READ */ |
1324 | ||
cf40bd16 | 1325 | /* |
4f367d8a PZ |
1326 | * Prove that the new dependency does not connect a hardirq-safe-read |
1327 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1328 | * the backwards-subgraph starting at <prev>, and the |
1329 | * forwards-subgraph starting at <next>: | |
1330 | */ | |
4f367d8a PZ |
1331 | if (!check_usage(curr, prev, next, bit, |
1332 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1333 | return 0; |
1334 | ||
4f367d8a PZ |
1335 | return 1; |
1336 | } | |
1337 | ||
1338 | static int | |
1339 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1340 | struct held_lock *next) | |
1341 | { | |
1342 | #define LOCKDEP_STATE(__STATE) \ | |
1343 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1344 | return 0; |
4f367d8a PZ |
1345 | #include "lockdep_states.h" |
1346 | #undef LOCKDEP_STATE | |
cf40bd16 | 1347 | |
8e18257d PZ |
1348 | return 1; |
1349 | } | |
1350 | ||
1351 | static void inc_chains(void) | |
1352 | { | |
1353 | if (current->hardirq_context) | |
1354 | nr_hardirq_chains++; | |
1355 | else { | |
1356 | if (current->softirq_context) | |
1357 | nr_softirq_chains++; | |
1358 | else | |
1359 | nr_process_chains++; | |
1360 | } | |
1361 | } | |
1362 | ||
1363 | #else | |
1364 | ||
1365 | static inline int | |
1366 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1367 | struct held_lock *next) | |
1368 | { | |
1369 | return 1; | |
1370 | } | |
1371 | ||
1372 | static inline void inc_chains(void) | |
1373 | { | |
1374 | nr_process_chains++; | |
1375 | } | |
1376 | ||
fbb9ce95 IM |
1377 | #endif |
1378 | ||
1379 | static int | |
1380 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1381 | struct held_lock *next) | |
1382 | { | |
74c383f1 | 1383 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1384 | return 0; |
1385 | ||
1386 | printk("\n=============================================\n"); | |
1387 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1388 | print_kernel_version(); |
fbb9ce95 IM |
1389 | printk( "---------------------------------------------\n"); |
1390 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1391 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1392 | print_lock(next); |
1393 | printk("\nbut task is already holding lock:\n"); | |
1394 | print_lock(prev); | |
1395 | ||
1396 | printk("\nother info that might help us debug this:\n"); | |
1397 | lockdep_print_held_locks(curr); | |
1398 | ||
1399 | printk("\nstack backtrace:\n"); | |
1400 | dump_stack(); | |
1401 | ||
1402 | return 0; | |
1403 | } | |
1404 | ||
1405 | /* | |
1406 | * Check whether we are holding such a class already. | |
1407 | * | |
1408 | * (Note that this has to be done separately, because the graph cannot | |
1409 | * detect such classes of deadlocks.) | |
1410 | * | |
1411 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1412 | */ | |
1413 | static int | |
1414 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1415 | struct lockdep_map *next_instance, int read) | |
1416 | { | |
1417 | struct held_lock *prev; | |
7531e2f3 | 1418 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1419 | int i; |
1420 | ||
1421 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1422 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1423 | |
1424 | if (prev->instance == next->nest_lock) | |
1425 | nest = prev; | |
1426 | ||
f82b217e | 1427 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1428 | continue; |
7531e2f3 | 1429 | |
fbb9ce95 IM |
1430 | /* |
1431 | * Allow read-after-read recursion of the same | |
6c9076ec | 1432 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1433 | */ |
6c9076ec | 1434 | if ((read == 2) && prev->read) |
fbb9ce95 | 1435 | return 2; |
7531e2f3 PZ |
1436 | |
1437 | /* | |
1438 | * We're holding the nest_lock, which serializes this lock's | |
1439 | * nesting behaviour. | |
1440 | */ | |
1441 | if (nest) | |
1442 | return 2; | |
1443 | ||
fbb9ce95 IM |
1444 | return print_deadlock_bug(curr, prev, next); |
1445 | } | |
1446 | return 1; | |
1447 | } | |
1448 | ||
1449 | /* | |
1450 | * There was a chain-cache miss, and we are about to add a new dependency | |
1451 | * to a previous lock. We recursively validate the following rules: | |
1452 | * | |
1453 | * - would the adding of the <prev> -> <next> dependency create a | |
1454 | * circular dependency in the graph? [== circular deadlock] | |
1455 | * | |
1456 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1457 | * (in the full backwards-subgraph starting at <prev>) with any | |
1458 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1459 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1460 | * | |
1461 | * - does the new prev->next dependency connect any softirq-safe lock | |
1462 | * (in the full backwards-subgraph starting at <prev>) with any | |
1463 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1464 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1465 | * | |
1466 | * any of these scenarios could lead to a deadlock. | |
1467 | * | |
1468 | * Then if all the validations pass, we add the forwards and backwards | |
1469 | * dependency. | |
1470 | */ | |
1471 | static int | |
1472 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1473 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1474 | { |
1475 | struct lock_list *entry; | |
1476 | int ret; | |
1477 | ||
1478 | /* | |
1479 | * Prove that the new <prev> -> <next> dependency would not | |
1480 | * create a circular dependency in the graph. (We do this by | |
1481 | * forward-recursing into the graph starting at <next>, and | |
1482 | * checking whether we can reach <prev>.) | |
1483 | * | |
1484 | * We are using global variables to control the recursion, to | |
1485 | * keep the stackframe size of the recursive functions low: | |
1486 | */ | |
1487 | check_source = next; | |
1488 | check_target = prev; | |
f82b217e | 1489 | if (!(check_noncircular(hlock_class(next), 0))) |
fbb9ce95 IM |
1490 | return print_circular_bug_tail(); |
1491 | ||
8e18257d | 1492 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1493 | return 0; |
1494 | ||
fbb9ce95 IM |
1495 | /* |
1496 | * For recursive read-locks we do all the dependency checks, | |
1497 | * but we dont store read-triggered dependencies (only | |
1498 | * write-triggered dependencies). This ensures that only the | |
1499 | * write-side dependencies matter, and that if for example a | |
1500 | * write-lock never takes any other locks, then the reads are | |
1501 | * equivalent to a NOP. | |
1502 | */ | |
1503 | if (next->read == 2 || prev->read == 2) | |
1504 | return 1; | |
1505 | /* | |
1506 | * Is the <prev> -> <next> dependency already present? | |
1507 | * | |
1508 | * (this may occur even though this is a new chain: consider | |
1509 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1510 | * chains - the second one will be new, but L1 already has | |
1511 | * L2 added to its dependency list, due to the first chain.) | |
1512 | */ | |
f82b217e DJ |
1513 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1514 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1515 | if (distance == 1) |
1516 | entry->distance = 1; | |
fbb9ce95 | 1517 | return 2; |
068135e6 | 1518 | } |
fbb9ce95 IM |
1519 | } |
1520 | ||
1521 | /* | |
1522 | * Ok, all validations passed, add the new lock | |
1523 | * to the previous lock's dependency list: | |
1524 | */ | |
f82b217e DJ |
1525 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1526 | &hlock_class(prev)->locks_after, | |
1527 | next->acquire_ip, distance); | |
068135e6 | 1528 | |
fbb9ce95 IM |
1529 | if (!ret) |
1530 | return 0; | |
910b1b2e | 1531 | |
f82b217e DJ |
1532 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1533 | &hlock_class(next)->locks_before, | |
1534 | next->acquire_ip, distance); | |
910b1b2e JP |
1535 | if (!ret) |
1536 | return 0; | |
fbb9ce95 IM |
1537 | |
1538 | /* | |
8e18257d PZ |
1539 | * Debugging printouts: |
1540 | */ | |
f82b217e | 1541 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1542 | graph_unlock(); |
1543 | printk("\n new dependency: "); | |
f82b217e | 1544 | print_lock_name(hlock_class(prev)); |
8e18257d | 1545 | printk(" => "); |
f82b217e | 1546 | print_lock_name(hlock_class(next)); |
8e18257d | 1547 | printk("\n"); |
fbb9ce95 | 1548 | dump_stack(); |
8e18257d | 1549 | return graph_lock(); |
fbb9ce95 | 1550 | } |
8e18257d PZ |
1551 | return 1; |
1552 | } | |
fbb9ce95 | 1553 | |
8e18257d PZ |
1554 | /* |
1555 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1556 | * The ones that are relevant are (in increasing distance from curr): | |
1557 | * all consecutive trylock entries and the final non-trylock entry - or | |
1558 | * the end of this context's lock-chain - whichever comes first. | |
1559 | */ | |
1560 | static int | |
1561 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1562 | { | |
1563 | int depth = curr->lockdep_depth; | |
1564 | struct held_lock *hlock; | |
d6d897ce | 1565 | |
fbb9ce95 | 1566 | /* |
8e18257d PZ |
1567 | * Debugging checks. |
1568 | * | |
1569 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1570 | */ |
8e18257d PZ |
1571 | if (!depth) |
1572 | goto out_bug; | |
fbb9ce95 | 1573 | /* |
8e18257d PZ |
1574 | * At least two relevant locks must exist for this |
1575 | * to be a head: | |
fbb9ce95 | 1576 | */ |
8e18257d PZ |
1577 | if (curr->held_locks[depth].irq_context != |
1578 | curr->held_locks[depth-1].irq_context) | |
1579 | goto out_bug; | |
74c383f1 | 1580 | |
8e18257d PZ |
1581 | for (;;) { |
1582 | int distance = curr->lockdep_depth - depth + 1; | |
1583 | hlock = curr->held_locks + depth-1; | |
1584 | /* | |
1585 | * Only non-recursive-read entries get new dependencies | |
1586 | * added: | |
1587 | */ | |
1588 | if (hlock->read != 2) { | |
1589 | if (!check_prev_add(curr, hlock, next, distance)) | |
1590 | return 0; | |
1591 | /* | |
1592 | * Stop after the first non-trylock entry, | |
1593 | * as non-trylock entries have added their | |
1594 | * own direct dependencies already, so this | |
1595 | * lock is connected to them indirectly: | |
1596 | */ | |
1597 | if (!hlock->trylock) | |
1598 | break; | |
74c383f1 | 1599 | } |
8e18257d PZ |
1600 | depth--; |
1601 | /* | |
1602 | * End of lock-stack? | |
1603 | */ | |
1604 | if (!depth) | |
1605 | break; | |
1606 | /* | |
1607 | * Stop the search if we cross into another context: | |
1608 | */ | |
1609 | if (curr->held_locks[depth].irq_context != | |
1610 | curr->held_locks[depth-1].irq_context) | |
1611 | break; | |
fbb9ce95 | 1612 | } |
8e18257d PZ |
1613 | return 1; |
1614 | out_bug: | |
1615 | if (!debug_locks_off_graph_unlock()) | |
1616 | return 0; | |
fbb9ce95 | 1617 | |
8e18257d | 1618 | WARN_ON(1); |
fbb9ce95 | 1619 | |
8e18257d | 1620 | return 0; |
fbb9ce95 IM |
1621 | } |
1622 | ||
8e18257d | 1623 | unsigned long nr_lock_chains; |
443cd507 | 1624 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1625 | int nr_chain_hlocks; |
443cd507 HY |
1626 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1627 | ||
1628 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1629 | { | |
1630 | return lock_classes + chain_hlocks[chain->base + i]; | |
1631 | } | |
8e18257d | 1632 | |
fbb9ce95 IM |
1633 | /* |
1634 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1635 | * add it and return 1 - in this case the new dependency chain is |
1636 | * validated. If the key is already hashed, return 0. | |
1637 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1638 | */ |
443cd507 HY |
1639 | static inline int lookup_chain_cache(struct task_struct *curr, |
1640 | struct held_lock *hlock, | |
1641 | u64 chain_key) | |
fbb9ce95 | 1642 | { |
f82b217e | 1643 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1644 | struct list_head *hash_head = chainhashentry(chain_key); |
1645 | struct lock_chain *chain; | |
443cd507 | 1646 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1647 | int i, j, n, cn; |
fbb9ce95 | 1648 | |
381a2292 JP |
1649 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1650 | return 0; | |
fbb9ce95 IM |
1651 | /* |
1652 | * We can walk it lock-free, because entries only get added | |
1653 | * to the hash: | |
1654 | */ | |
1655 | list_for_each_entry(chain, hash_head, entry) { | |
1656 | if (chain->chain_key == chain_key) { | |
1657 | cache_hit: | |
1658 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1659 | if (very_verbose(class)) |
755cd900 AM |
1660 | printk("\nhash chain already cached, key: " |
1661 | "%016Lx tail class: [%p] %s\n", | |
1662 | (unsigned long long)chain_key, | |
1663 | class->key, class->name); | |
fbb9ce95 IM |
1664 | return 0; |
1665 | } | |
1666 | } | |
81fc685a | 1667 | if (very_verbose(class)) |
755cd900 AM |
1668 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1669 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1670 | /* |
1671 | * Allocate a new chain entry from the static array, and add | |
1672 | * it to the hash: | |
1673 | */ | |
74c383f1 IM |
1674 | if (!graph_lock()) |
1675 | return 0; | |
fbb9ce95 IM |
1676 | /* |
1677 | * We have to walk the chain again locked - to avoid duplicates: | |
1678 | */ | |
1679 | list_for_each_entry(chain, hash_head, entry) { | |
1680 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1681 | graph_unlock(); |
fbb9ce95 IM |
1682 | goto cache_hit; |
1683 | } | |
1684 | } | |
1685 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1686 | if (!debug_locks_off_graph_unlock()) |
1687 | return 0; | |
1688 | ||
fbb9ce95 IM |
1689 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1690 | printk("turning off the locking correctness validator.\n"); | |
1691 | return 0; | |
1692 | } | |
1693 | chain = lock_chains + nr_lock_chains++; | |
1694 | chain->chain_key = chain_key; | |
443cd507 HY |
1695 | chain->irq_context = hlock->irq_context; |
1696 | /* Find the first held_lock of current chain */ | |
1697 | hlock_next = hlock; | |
1698 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1699 | hlock_curr = curr->held_locks + i; | |
1700 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1701 | break; | |
1702 | hlock_next = hlock; | |
1703 | } | |
1704 | i++; | |
1705 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1706 | cn = nr_chain_hlocks; |
1707 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1708 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1709 | if (n == cn) | |
1710 | break; | |
1711 | cn = n; | |
1712 | } | |
1713 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1714 | chain->base = cn; | |
443cd507 | 1715 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1716 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1717 | chain_hlocks[chain->base + j] = lock_id; |
1718 | } | |
1719 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1720 | } | |
fbb9ce95 IM |
1721 | list_add_tail_rcu(&chain->entry, hash_head); |
1722 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1723 | inc_chains(); |
1724 | ||
1725 | return 1; | |
1726 | } | |
1727 | ||
1728 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1729 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1730 | { |
1731 | /* | |
1732 | * Trylock needs to maintain the stack of held locks, but it | |
1733 | * does not add new dependencies, because trylock can be done | |
1734 | * in any order. | |
1735 | * | |
1736 | * We look up the chain_key and do the O(N^2) check and update of | |
1737 | * the dependencies only if this is a new dependency chain. | |
1738 | * (If lookup_chain_cache() returns with 1 it acquires | |
1739 | * graph_lock for us) | |
1740 | */ | |
1741 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1742 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1743 | /* |
1744 | * Check whether last held lock: | |
1745 | * | |
1746 | * - is irq-safe, if this lock is irq-unsafe | |
1747 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1748 | * | |
1749 | * And check whether the new lock's dependency graph | |
1750 | * could lead back to the previous lock. | |
1751 | * | |
1752 | * any of these scenarios could lead to a deadlock. If | |
1753 | * All validations | |
1754 | */ | |
1755 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1756 | ||
1757 | if (!ret) | |
1758 | return 0; | |
1759 | /* | |
1760 | * Mark recursive read, as we jump over it when | |
1761 | * building dependencies (just like we jump over | |
1762 | * trylock entries): | |
1763 | */ | |
1764 | if (ret == 2) | |
1765 | hlock->read = 2; | |
1766 | /* | |
1767 | * Add dependency only if this lock is not the head | |
1768 | * of the chain, and if it's not a secondary read-lock: | |
1769 | */ | |
1770 | if (!chain_head && ret != 2) | |
1771 | if (!check_prevs_add(curr, hlock)) | |
1772 | return 0; | |
1773 | graph_unlock(); | |
1774 | } else | |
1775 | /* after lookup_chain_cache(): */ | |
1776 | if (unlikely(!debug_locks)) | |
1777 | return 0; | |
fbb9ce95 IM |
1778 | |
1779 | return 1; | |
1780 | } | |
8e18257d PZ |
1781 | #else |
1782 | static inline int validate_chain(struct task_struct *curr, | |
1783 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1784 | int chain_head, u64 chain_key) |
8e18257d PZ |
1785 | { |
1786 | return 1; | |
1787 | } | |
ca58abcb | 1788 | #endif |
fbb9ce95 IM |
1789 | |
1790 | /* | |
1791 | * We are building curr_chain_key incrementally, so double-check | |
1792 | * it from scratch, to make sure that it's done correctly: | |
1793 | */ | |
1d09daa5 | 1794 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1795 | { |
1796 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1797 | struct held_lock *hlock, *prev_hlock = NULL; | |
1798 | unsigned int i, id; | |
1799 | u64 chain_key = 0; | |
1800 | ||
1801 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1802 | hlock = curr->held_locks + i; | |
1803 | if (chain_key != hlock->prev_chain_key) { | |
1804 | debug_locks_off(); | |
2df8b1d6 | 1805 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1806 | curr->lockdep_depth, i, |
1807 | (unsigned long long)chain_key, | |
1808 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1809 | return; |
1810 | } | |
f82b217e | 1811 | id = hlock->class_idx - 1; |
381a2292 JP |
1812 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1813 | return; | |
1814 | ||
fbb9ce95 IM |
1815 | if (prev_hlock && (prev_hlock->irq_context != |
1816 | hlock->irq_context)) | |
1817 | chain_key = 0; | |
1818 | chain_key = iterate_chain_key(chain_key, id); | |
1819 | prev_hlock = hlock; | |
1820 | } | |
1821 | if (chain_key != curr->curr_chain_key) { | |
1822 | debug_locks_off(); | |
2df8b1d6 | 1823 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1824 | curr->lockdep_depth, i, |
1825 | (unsigned long long)chain_key, | |
1826 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1827 | } |
1828 | #endif | |
1829 | } | |
1830 | ||
8e18257d PZ |
1831 | static int |
1832 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1833 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1834 | { | |
1835 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1836 | return 0; | |
1837 | ||
1838 | printk("\n=================================\n"); | |
1839 | printk( "[ INFO: inconsistent lock state ]\n"); | |
1840 | print_kernel_version(); | |
1841 | printk( "---------------------------------\n"); | |
1842 | ||
1843 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1844 | usage_str[prev_bit], usage_str[new_bit]); | |
1845 | ||
1846 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 1847 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
1848 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
1849 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1850 | trace_hardirqs_enabled(curr), | |
1851 | trace_softirqs_enabled(curr)); | |
1852 | print_lock(this); | |
1853 | ||
1854 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 1855 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
1856 | |
1857 | print_irqtrace_events(curr); | |
1858 | printk("\nother info that might help us debug this:\n"); | |
1859 | lockdep_print_held_locks(curr); | |
1860 | ||
1861 | printk("\nstack backtrace:\n"); | |
1862 | dump_stack(); | |
1863 | ||
1864 | return 0; | |
1865 | } | |
1866 | ||
1867 | /* | |
1868 | * Print out an error if an invalid bit is set: | |
1869 | */ | |
1870 | static inline int | |
1871 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1872 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1873 | { | |
f82b217e | 1874 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
1875 | return print_usage_bug(curr, this, bad_bit, new_bit); |
1876 | return 1; | |
1877 | } | |
1878 | ||
1879 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
1880 | enum lock_usage_bit new_bit); | |
1881 | ||
81d68a96 | 1882 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1883 | |
1884 | /* | |
1885 | * print irq inversion bug: | |
1886 | */ | |
1887 | static int | |
1888 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, | |
1889 | struct held_lock *this, int forwards, | |
1890 | const char *irqclass) | |
1891 | { | |
74c383f1 | 1892 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1893 | return 0; |
1894 | ||
1895 | printk("\n=========================================================\n"); | |
1896 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 1897 | print_kernel_version(); |
fbb9ce95 IM |
1898 | printk( "---------------------------------------------------------\n"); |
1899 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 1900 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1901 | print_lock(this); |
1902 | if (forwards) | |
26575e28 | 1903 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 1904 | else |
26575e28 | 1905 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
fbb9ce95 IM |
1906 | print_lock_name(other); |
1907 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); | |
1908 | ||
1909 | printk("\nother info that might help us debug this:\n"); | |
1910 | lockdep_print_held_locks(curr); | |
1911 | ||
1912 | printk("\nthe first lock's dependencies:\n"); | |
f82b217e | 1913 | print_lock_dependencies(hlock_class(this), 0); |
fbb9ce95 IM |
1914 | |
1915 | printk("\nthe second lock's dependencies:\n"); | |
1916 | print_lock_dependencies(other, 0); | |
1917 | ||
1918 | printk("\nstack backtrace:\n"); | |
1919 | dump_stack(); | |
1920 | ||
1921 | return 0; | |
1922 | } | |
1923 | ||
1924 | /* | |
1925 | * Prove that in the forwards-direction subgraph starting at <this> | |
1926 | * there is no lock matching <mask>: | |
1927 | */ | |
1928 | static int | |
1929 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
1930 | enum lock_usage_bit bit, const char *irqclass) | |
1931 | { | |
1932 | int ret; | |
1933 | ||
1934 | find_usage_bit = bit; | |
1935 | /* fills in <forwards_match> */ | |
f82b217e | 1936 | ret = find_usage_forwards(hlock_class(this), 0); |
fbb9ce95 IM |
1937 | if (!ret || ret == 1) |
1938 | return ret; | |
1939 | ||
1940 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); | |
1941 | } | |
1942 | ||
1943 | /* | |
1944 | * Prove that in the backwards-direction subgraph starting at <this> | |
1945 | * there is no lock matching <mask>: | |
1946 | */ | |
1947 | static int | |
1948 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
1949 | enum lock_usage_bit bit, const char *irqclass) | |
1950 | { | |
1951 | int ret; | |
1952 | ||
1953 | find_usage_bit = bit; | |
1954 | /* fills in <backwards_match> */ | |
f82b217e | 1955 | ret = find_usage_backwards(hlock_class(this), 0); |
fbb9ce95 IM |
1956 | if (!ret || ret == 1) |
1957 | return ret; | |
1958 | ||
1959 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); | |
1960 | } | |
1961 | ||
3117df04 | 1962 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
1963 | { |
1964 | printk("irq event stamp: %u\n", curr->irq_events); | |
1965 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
1966 | print_ip_sym(curr->hardirq_enable_ip); | |
1967 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
1968 | print_ip_sym(curr->hardirq_disable_ip); | |
1969 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
1970 | print_ip_sym(curr->softirq_enable_ip); | |
1971 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
1972 | print_ip_sym(curr->softirq_disable_ip); | |
1973 | } | |
1974 | ||
cd95302d | 1975 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 1976 | { |
8e18257d PZ |
1977 | #if HARDIRQ_VERBOSE |
1978 | return class_filter(class); | |
1979 | #endif | |
fbb9ce95 IM |
1980 | return 0; |
1981 | } | |
1982 | ||
cd95302d | 1983 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 1984 | { |
8e18257d PZ |
1985 | #if SOFTIRQ_VERBOSE |
1986 | return class_filter(class); | |
1987 | #endif | |
1988 | return 0; | |
fbb9ce95 IM |
1989 | } |
1990 | ||
cd95302d | 1991 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
1992 | { |
1993 | #if RECLAIM_VERBOSE | |
1994 | return class_filter(class); | |
1995 | #endif | |
1996 | return 0; | |
1997 | } | |
1998 | ||
fbb9ce95 IM |
1999 | #define STRICT_READ_CHECKS 1 |
2000 | ||
cd95302d PZ |
2001 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2002 | #define LOCKDEP_STATE(__STATE) \ | |
2003 | __STATE##_verbose, | |
2004 | #include "lockdep_states.h" | |
2005 | #undef LOCKDEP_STATE | |
2006 | }; | |
2007 | ||
2008 | static inline int state_verbose(enum lock_usage_bit bit, | |
2009 | struct lock_class *class) | |
2010 | { | |
2011 | return state_verbose_f[bit >> 2](class); | |
2012 | } | |
2013 | ||
42c50d54 PZ |
2014 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2015 | enum lock_usage_bit bit, const char *name); | |
2016 | ||
6a6904d3 | 2017 | static int |
1c21f14e PZ |
2018 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2019 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2020 | { |
f989209e | 2021 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2022 | int read = new_bit & 1; |
42c50d54 PZ |
2023 | int dir = new_bit & 2; |
2024 | ||
38aa2714 PZ |
2025 | /* |
2026 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2027 | * has ENABLED state, which would allow recursion deadlocks. | |
2028 | * | |
2029 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2030 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2031 | */ | |
42c50d54 PZ |
2032 | check_usage_f usage = dir ? |
2033 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2034 | |
38aa2714 PZ |
2035 | /* |
2036 | * Validate that this particular lock does not have conflicting | |
2037 | * usage states. | |
2038 | */ | |
6a6904d3 PZ |
2039 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2040 | return 0; | |
42c50d54 | 2041 | |
38aa2714 PZ |
2042 | /* |
2043 | * Validate that the lock dependencies don't have conflicting usage | |
2044 | * states. | |
2045 | */ | |
2046 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2047 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2048 | return 0; |
780e820b | 2049 | |
38aa2714 PZ |
2050 | /* |
2051 | * Check for read in write conflicts | |
2052 | */ | |
2053 | if (!read) { | |
2054 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2055 | return 0; | |
2056 | ||
2057 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2058 | !usage(curr, this, excl_bit + 1, |
2059 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2060 | return 0; |
2061 | } | |
780e820b | 2062 | |
cd95302d | 2063 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2064 | return 2; |
2065 | ||
2066 | return 1; | |
2067 | } | |
2068 | ||
cf40bd16 | 2069 | enum mark_type { |
36bfb9bb PZ |
2070 | #define LOCKDEP_STATE(__STATE) __STATE, |
2071 | #include "lockdep_states.h" | |
2072 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2073 | }; |
2074 | ||
fbb9ce95 IM |
2075 | /* |
2076 | * Mark all held locks with a usage bit: | |
2077 | */ | |
1d09daa5 | 2078 | static int |
cf40bd16 | 2079 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2080 | { |
2081 | enum lock_usage_bit usage_bit; | |
2082 | struct held_lock *hlock; | |
2083 | int i; | |
2084 | ||
2085 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2086 | hlock = curr->held_locks + i; | |
2087 | ||
cf2ad4d1 PZ |
2088 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2089 | if (hlock->read) | |
2090 | usage_bit += 1; /* READ */ | |
2091 | ||
2092 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2093 | |
4ff773bb | 2094 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2095 | return 0; |
2096 | } | |
2097 | ||
2098 | return 1; | |
2099 | } | |
2100 | ||
2101 | /* | |
2102 | * Debugging helper: via this flag we know that we are in | |
2103 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2104 | */ | |
2105 | static int early_boot_irqs_enabled; | |
2106 | ||
2107 | void early_boot_irqs_off(void) | |
2108 | { | |
2109 | early_boot_irqs_enabled = 0; | |
2110 | } | |
2111 | ||
2112 | void early_boot_irqs_on(void) | |
2113 | { | |
2114 | early_boot_irqs_enabled = 1; | |
2115 | } | |
2116 | ||
2117 | /* | |
2118 | * Hardirqs will be enabled: | |
2119 | */ | |
6afe40b4 | 2120 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2121 | { |
2122 | struct task_struct *curr = current; | |
fbb9ce95 | 2123 | |
6afe40b4 | 2124 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2125 | |
fbb9ce95 IM |
2126 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2127 | return; | |
2128 | ||
2129 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2130 | return; | |
2131 | ||
2132 | if (unlikely(curr->hardirqs_enabled)) { | |
2133 | debug_atomic_inc(&redundant_hardirqs_on); | |
2134 | return; | |
2135 | } | |
2136 | /* we'll do an OFF -> ON transition: */ | |
2137 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2138 | |
2139 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2140 | return; | |
2141 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2142 | return; | |
2143 | /* | |
2144 | * We are going to turn hardirqs on, so set the | |
2145 | * usage bit for all held locks: | |
2146 | */ | |
cf40bd16 | 2147 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2148 | return; |
2149 | /* | |
2150 | * If we have softirqs enabled, then set the usage | |
2151 | * bit for all held locks. (disabled hardirqs prevented | |
2152 | * this bit from being set before) | |
2153 | */ | |
2154 | if (curr->softirqs_enabled) | |
cf40bd16 | 2155 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2156 | return; |
2157 | ||
8e18257d PZ |
2158 | curr->hardirq_enable_ip = ip; |
2159 | curr->hardirq_enable_event = ++curr->irq_events; | |
2160 | debug_atomic_inc(&hardirqs_on_events); | |
2161 | } | |
81d68a96 | 2162 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2163 | |
1d09daa5 | 2164 | void trace_hardirqs_on(void) |
81d68a96 SR |
2165 | { |
2166 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2167 | } | |
8e18257d PZ |
2168 | EXPORT_SYMBOL(trace_hardirqs_on); |
2169 | ||
2170 | /* | |
2171 | * Hardirqs were disabled: | |
2172 | */ | |
6afe40b4 | 2173 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2174 | { |
2175 | struct task_struct *curr = current; | |
2176 | ||
6afe40b4 | 2177 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2178 | |
8e18257d PZ |
2179 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2180 | return; | |
2181 | ||
2182 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2183 | return; | |
2184 | ||
2185 | if (curr->hardirqs_enabled) { | |
2186 | /* | |
2187 | * We have done an ON -> OFF transition: | |
2188 | */ | |
2189 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2190 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2191 | curr->hardirq_disable_event = ++curr->irq_events; |
2192 | debug_atomic_inc(&hardirqs_off_events); | |
2193 | } else | |
2194 | debug_atomic_inc(&redundant_hardirqs_off); | |
2195 | } | |
81d68a96 | 2196 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2197 | |
1d09daa5 | 2198 | void trace_hardirqs_off(void) |
81d68a96 SR |
2199 | { |
2200 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2201 | } | |
8e18257d PZ |
2202 | EXPORT_SYMBOL(trace_hardirqs_off); |
2203 | ||
2204 | /* | |
2205 | * Softirqs will be enabled: | |
2206 | */ | |
2207 | void trace_softirqs_on(unsigned long ip) | |
2208 | { | |
2209 | struct task_struct *curr = current; | |
2210 | ||
2211 | if (unlikely(!debug_locks)) | |
2212 | return; | |
2213 | ||
2214 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2215 | return; | |
2216 | ||
2217 | if (curr->softirqs_enabled) { | |
2218 | debug_atomic_inc(&redundant_softirqs_on); | |
2219 | return; | |
2220 | } | |
2221 | ||
2222 | /* | |
2223 | * We'll do an OFF -> ON transition: | |
2224 | */ | |
2225 | curr->softirqs_enabled = 1; | |
2226 | curr->softirq_enable_ip = ip; | |
2227 | curr->softirq_enable_event = ++curr->irq_events; | |
2228 | debug_atomic_inc(&softirqs_on_events); | |
2229 | /* | |
2230 | * We are going to turn softirqs on, so set the | |
2231 | * usage bit for all held locks, if hardirqs are | |
2232 | * enabled too: | |
2233 | */ | |
2234 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2235 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2236 | } |
2237 | ||
2238 | /* | |
2239 | * Softirqs were disabled: | |
2240 | */ | |
2241 | void trace_softirqs_off(unsigned long ip) | |
2242 | { | |
2243 | struct task_struct *curr = current; | |
2244 | ||
2245 | if (unlikely(!debug_locks)) | |
2246 | return; | |
2247 | ||
2248 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2249 | return; | |
2250 | ||
2251 | if (curr->softirqs_enabled) { | |
2252 | /* | |
2253 | * We have done an ON -> OFF transition: | |
2254 | */ | |
2255 | curr->softirqs_enabled = 0; | |
2256 | curr->softirq_disable_ip = ip; | |
2257 | curr->softirq_disable_event = ++curr->irq_events; | |
2258 | debug_atomic_inc(&softirqs_off_events); | |
2259 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2260 | } else | |
2261 | debug_atomic_inc(&redundant_softirqs_off); | |
2262 | } | |
2263 | ||
cf40bd16 NP |
2264 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2265 | { | |
2266 | struct task_struct *curr = current; | |
2267 | ||
2268 | if (unlikely(!debug_locks)) | |
2269 | return; | |
2270 | ||
2271 | /* no reclaim without waiting on it */ | |
2272 | if (!(gfp_mask & __GFP_WAIT)) | |
2273 | return; | |
2274 | ||
2275 | /* this guy won't enter reclaim */ | |
2276 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2277 | return; | |
2278 | ||
2279 | /* We're only interested __GFP_FS allocations for now */ | |
2280 | if (!(gfp_mask & __GFP_FS)) | |
2281 | return; | |
2282 | ||
2283 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled())) | |
2284 | return; | |
2285 | ||
2286 | mark_held_locks(curr, RECLAIM_FS); | |
2287 | } | |
2288 | ||
8e18257d PZ |
2289 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2290 | { | |
2291 | /* | |
2292 | * If non-trylock use in a hardirq or softirq context, then | |
2293 | * mark the lock as used in these contexts: | |
2294 | */ | |
2295 | if (!hlock->trylock) { | |
2296 | if (hlock->read) { | |
2297 | if (curr->hardirq_context) | |
2298 | if (!mark_lock(curr, hlock, | |
2299 | LOCK_USED_IN_HARDIRQ_READ)) | |
2300 | return 0; | |
2301 | if (curr->softirq_context) | |
2302 | if (!mark_lock(curr, hlock, | |
2303 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2304 | return 0; | |
2305 | } else { | |
2306 | if (curr->hardirq_context) | |
2307 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2308 | return 0; | |
2309 | if (curr->softirq_context) | |
2310 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2311 | return 0; | |
2312 | } | |
2313 | } | |
2314 | if (!hlock->hardirqs_off) { | |
2315 | if (hlock->read) { | |
2316 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2317 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2318 | return 0; |
2319 | if (curr->softirqs_enabled) | |
2320 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2321 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2322 | return 0; |
2323 | } else { | |
2324 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2325 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2326 | return 0; |
2327 | if (curr->softirqs_enabled) | |
2328 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2329 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2330 | return 0; |
2331 | } | |
2332 | } | |
2333 | ||
cf40bd16 NP |
2334 | /* |
2335 | * We reuse the irq context infrastructure more broadly as a general | |
2336 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2337 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2338 | * allocation). | |
2339 | */ | |
2340 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2341 | if (hlock->read) { | |
2342 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2343 | return 0; | |
2344 | } else { | |
2345 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2346 | return 0; | |
2347 | } | |
2348 | } | |
2349 | ||
8e18257d PZ |
2350 | return 1; |
2351 | } | |
2352 | ||
2353 | static int separate_irq_context(struct task_struct *curr, | |
2354 | struct held_lock *hlock) | |
2355 | { | |
2356 | unsigned int depth = curr->lockdep_depth; | |
2357 | ||
2358 | /* | |
2359 | * Keep track of points where we cross into an interrupt context: | |
2360 | */ | |
2361 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2362 | curr->softirq_context; | |
2363 | if (depth) { | |
2364 | struct held_lock *prev_hlock; | |
2365 | ||
2366 | prev_hlock = curr->held_locks + depth-1; | |
2367 | /* | |
2368 | * If we cross into another context, reset the | |
2369 | * hash key (this also prevents the checking and the | |
2370 | * adding of the dependency to 'prev'): | |
2371 | */ | |
2372 | if (prev_hlock->irq_context != hlock->irq_context) | |
2373 | return 1; | |
2374 | } | |
2375 | return 0; | |
fbb9ce95 IM |
2376 | } |
2377 | ||
8e18257d | 2378 | #else |
fbb9ce95 | 2379 | |
8e18257d PZ |
2380 | static inline |
2381 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2382 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2383 | { |
8e18257d PZ |
2384 | WARN_ON(1); |
2385 | return 1; | |
2386 | } | |
fbb9ce95 | 2387 | |
8e18257d PZ |
2388 | static inline int mark_irqflags(struct task_struct *curr, |
2389 | struct held_lock *hlock) | |
2390 | { | |
2391 | return 1; | |
2392 | } | |
fbb9ce95 | 2393 | |
8e18257d PZ |
2394 | static inline int separate_irq_context(struct task_struct *curr, |
2395 | struct held_lock *hlock) | |
2396 | { | |
2397 | return 0; | |
fbb9ce95 IM |
2398 | } |
2399 | ||
868a23a8 PZ |
2400 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2401 | { | |
2402 | } | |
2403 | ||
8e18257d | 2404 | #endif |
fbb9ce95 IM |
2405 | |
2406 | /* | |
8e18257d | 2407 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2408 | */ |
1d09daa5 | 2409 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2410 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2411 | { |
8e18257d | 2412 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2413 | |
2414 | /* | |
8e18257d PZ |
2415 | * If already set then do not dirty the cacheline, |
2416 | * nor do any checks: | |
fbb9ce95 | 2417 | */ |
f82b217e | 2418 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2419 | return 1; |
2420 | ||
2421 | if (!graph_lock()) | |
2422 | return 0; | |
fbb9ce95 | 2423 | /* |
8e18257d | 2424 | * Make sure we didnt race: |
fbb9ce95 | 2425 | */ |
f82b217e | 2426 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2427 | graph_unlock(); |
2428 | return 1; | |
2429 | } | |
fbb9ce95 | 2430 | |
f82b217e | 2431 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2432 | |
f82b217e | 2433 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2434 | return 0; |
fbb9ce95 | 2435 | |
8e18257d | 2436 | switch (new_bit) { |
5346417e PZ |
2437 | #define LOCKDEP_STATE(__STATE) \ |
2438 | case LOCK_USED_IN_##__STATE: \ | |
2439 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2440 | case LOCK_ENABLED_##__STATE: \ | |
2441 | case LOCK_ENABLED_##__STATE##_READ: | |
2442 | #include "lockdep_states.h" | |
2443 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2444 | ret = mark_lock_irq(curr, this, new_bit); |
2445 | if (!ret) | |
2446 | return 0; | |
2447 | break; | |
2448 | case LOCK_USED: | |
8e18257d PZ |
2449 | debug_atomic_dec(&nr_unused_locks); |
2450 | break; | |
2451 | default: | |
2452 | if (!debug_locks_off_graph_unlock()) | |
2453 | return 0; | |
2454 | WARN_ON(1); | |
2455 | return 0; | |
2456 | } | |
fbb9ce95 | 2457 | |
8e18257d PZ |
2458 | graph_unlock(); |
2459 | ||
2460 | /* | |
2461 | * We must printk outside of the graph_lock: | |
2462 | */ | |
2463 | if (ret == 2) { | |
2464 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2465 | print_lock(this); | |
2466 | print_irqtrace_events(curr); | |
2467 | dump_stack(); | |
2468 | } | |
2469 | ||
2470 | return ret; | |
2471 | } | |
fbb9ce95 IM |
2472 | |
2473 | /* | |
2474 | * Initialize a lock instance's lock-class mapping info: | |
2475 | */ | |
2476 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2477 | struct lock_class_key *key, int subclass) |
fbb9ce95 IM |
2478 | { |
2479 | if (unlikely(!debug_locks)) | |
2480 | return; | |
2481 | ||
2482 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2483 | return; | |
2484 | if (DEBUG_LOCKS_WARN_ON(!name)) | |
2485 | return; | |
2486 | /* | |
2487 | * Sanity check, the lock-class key must be persistent: | |
2488 | */ | |
2489 | if (!static_obj(key)) { | |
2490 | printk("BUG: key %p not in .data!\n", key); | |
2491 | DEBUG_LOCKS_WARN_ON(1); | |
2492 | return; | |
2493 | } | |
2494 | lock->name = name; | |
2495 | lock->key = key; | |
d6d897ce | 2496 | lock->class_cache = NULL; |
96645678 PZ |
2497 | #ifdef CONFIG_LOCK_STAT |
2498 | lock->cpu = raw_smp_processor_id(); | |
2499 | #endif | |
4dfbb9d8 PZ |
2500 | if (subclass) |
2501 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2502 | } |
fbb9ce95 IM |
2503 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2504 | ||
2505 | /* | |
2506 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2507 | * We maintain the dependency maps and validate the locking attempt: | |
2508 | */ | |
2509 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2510 | int trylock, int read, int check, int hardirqs_off, | |
7531e2f3 | 2511 | struct lockdep_map *nest_lock, unsigned long ip) |
fbb9ce95 IM |
2512 | { |
2513 | struct task_struct *curr = current; | |
d6d897ce | 2514 | struct lock_class *class = NULL; |
fbb9ce95 | 2515 | struct held_lock *hlock; |
fbb9ce95 IM |
2516 | unsigned int depth, id; |
2517 | int chain_head = 0; | |
2518 | u64 chain_key; | |
2519 | ||
f20786ff PZ |
2520 | if (!prove_locking) |
2521 | check = 1; | |
2522 | ||
fbb9ce95 IM |
2523 | if (unlikely(!debug_locks)) |
2524 | return 0; | |
2525 | ||
2526 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2527 | return 0; | |
2528 | ||
2529 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2530 | debug_locks_off(); | |
2531 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2532 | printk("turning off the locking correctness validator.\n"); | |
2533 | return 0; | |
2534 | } | |
2535 | ||
d6d897ce IM |
2536 | if (!subclass) |
2537 | class = lock->class_cache; | |
2538 | /* | |
2539 | * Not cached yet or subclass? | |
2540 | */ | |
fbb9ce95 | 2541 | if (unlikely(!class)) { |
4dfbb9d8 | 2542 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2543 | if (!class) |
2544 | return 0; | |
2545 | } | |
2546 | debug_atomic_inc((atomic_t *)&class->ops); | |
2547 | if (very_verbose(class)) { | |
2548 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2549 | if (class->name_version > 1) | |
2550 | printk("#%d", class->name_version); | |
2551 | printk("\n"); | |
2552 | dump_stack(); | |
2553 | } | |
2554 | ||
2555 | /* | |
2556 | * Add the lock to the list of currently held locks. | |
2557 | * (we dont increase the depth just yet, up until the | |
2558 | * dependency checks are done) | |
2559 | */ | |
2560 | depth = curr->lockdep_depth; | |
2561 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2562 | return 0; | |
2563 | ||
2564 | hlock = curr->held_locks + depth; | |
f82b217e DJ |
2565 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2566 | return 0; | |
2567 | hlock->class_idx = class - lock_classes + 1; | |
fbb9ce95 IM |
2568 | hlock->acquire_ip = ip; |
2569 | hlock->instance = lock; | |
7531e2f3 | 2570 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2571 | hlock->trylock = trylock; |
2572 | hlock->read = read; | |
2573 | hlock->check = check; | |
6951b12a | 2574 | hlock->hardirqs_off = !!hardirqs_off; |
f20786ff PZ |
2575 | #ifdef CONFIG_LOCK_STAT |
2576 | hlock->waittime_stamp = 0; | |
2577 | hlock->holdtime_stamp = sched_clock(); | |
2578 | #endif | |
fbb9ce95 | 2579 | |
8e18257d PZ |
2580 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2581 | return 0; | |
2582 | ||
fbb9ce95 | 2583 | /* mark it as used: */ |
4ff773bb | 2584 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2585 | return 0; |
8e18257d | 2586 | |
fbb9ce95 | 2587 | /* |
17aacfb9 | 2588 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2589 | * lock keys along the dependency chain. We save the hash value |
2590 | * at every step so that we can get the current hash easily | |
2591 | * after unlock. The chain hash is then used to cache dependency | |
2592 | * results. | |
2593 | * | |
2594 | * The 'key ID' is what is the most compact key value to drive | |
2595 | * the hash, not class->key. | |
2596 | */ | |
2597 | id = class - lock_classes; | |
2598 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2599 | return 0; | |
2600 | ||
2601 | chain_key = curr->curr_chain_key; | |
2602 | if (!depth) { | |
2603 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2604 | return 0; | |
2605 | chain_head = 1; | |
2606 | } | |
2607 | ||
2608 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2609 | if (separate_irq_context(curr, hlock)) { |
2610 | chain_key = 0; | |
2611 | chain_head = 1; | |
fbb9ce95 | 2612 | } |
fbb9ce95 | 2613 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2614 | |
3aa416b0 | 2615 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2616 | return 0; |
381a2292 | 2617 | |
3aa416b0 | 2618 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2619 | curr->lockdep_depth++; |
2620 | check_chain_key(curr); | |
60e114d1 JP |
2621 | #ifdef CONFIG_DEBUG_LOCKDEP |
2622 | if (unlikely(!debug_locks)) | |
2623 | return 0; | |
2624 | #endif | |
fbb9ce95 IM |
2625 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2626 | debug_locks_off(); | |
2627 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2628 | printk("turning off the locking correctness validator.\n"); | |
2629 | return 0; | |
2630 | } | |
381a2292 | 2631 | |
fbb9ce95 IM |
2632 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2633 | max_lockdep_depth = curr->lockdep_depth; | |
2634 | ||
2635 | return 1; | |
2636 | } | |
2637 | ||
2638 | static int | |
2639 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2640 | unsigned long ip) | |
2641 | { | |
2642 | if (!debug_locks_off()) | |
2643 | return 0; | |
2644 | if (debug_locks_silent) | |
2645 | return 0; | |
2646 | ||
2647 | printk("\n=====================================\n"); | |
2648 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2649 | printk( "-------------------------------------\n"); | |
2650 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2651 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2652 | print_lockdep_cache(lock); |
2653 | printk(") at:\n"); | |
2654 | print_ip_sym(ip); | |
2655 | printk("but there are no more locks to release!\n"); | |
2656 | printk("\nother info that might help us debug this:\n"); | |
2657 | lockdep_print_held_locks(curr); | |
2658 | ||
2659 | printk("\nstack backtrace:\n"); | |
2660 | dump_stack(); | |
2661 | ||
2662 | return 0; | |
2663 | } | |
2664 | ||
2665 | /* | |
2666 | * Common debugging checks for both nested and non-nested unlock: | |
2667 | */ | |
2668 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2669 | unsigned long ip) | |
2670 | { | |
2671 | if (unlikely(!debug_locks)) | |
2672 | return 0; | |
2673 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2674 | return 0; | |
2675 | ||
2676 | if (curr->lockdep_depth <= 0) | |
2677 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2678 | ||
2679 | return 1; | |
2680 | } | |
2681 | ||
64aa348e | 2682 | static int |
00ef9f73 PZ |
2683 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2684 | struct lock_class_key *key, unsigned int subclass, | |
2685 | unsigned long ip) | |
64aa348e PZ |
2686 | { |
2687 | struct task_struct *curr = current; | |
2688 | struct held_lock *hlock, *prev_hlock; | |
2689 | struct lock_class *class; | |
2690 | unsigned int depth; | |
2691 | int i; | |
2692 | ||
2693 | depth = curr->lockdep_depth; | |
2694 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2695 | return 0; | |
2696 | ||
2697 | prev_hlock = NULL; | |
2698 | for (i = depth-1; i >= 0; i--) { | |
2699 | hlock = curr->held_locks + i; | |
2700 | /* | |
2701 | * We must not cross into another context: | |
2702 | */ | |
2703 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2704 | break; | |
2705 | if (hlock->instance == lock) | |
2706 | goto found_it; | |
2707 | prev_hlock = hlock; | |
2708 | } | |
2709 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2710 | ||
2711 | found_it: | |
00ef9f73 | 2712 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2713 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2714 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2715 | |
2716 | curr->lockdep_depth = i; | |
2717 | curr->curr_chain_key = hlock->prev_chain_key; | |
2718 | ||
2719 | for (; i < depth; i++) { | |
2720 | hlock = curr->held_locks + i; | |
2721 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2722 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2723 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2724 | hlock->nest_lock, hlock->acquire_ip)) |
64aa348e PZ |
2725 | return 0; |
2726 | } | |
2727 | ||
2728 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2729 | return 0; | |
2730 | return 1; | |
2731 | } | |
2732 | ||
fbb9ce95 IM |
2733 | /* |
2734 | * Remove the lock to the list of currently held locks in a | |
2735 | * potentially non-nested (out of order) manner. This is a | |
2736 | * relatively rare operation, as all the unlock APIs default | |
2737 | * to nested mode (which uses lock_release()): | |
2738 | */ | |
2739 | static int | |
2740 | lock_release_non_nested(struct task_struct *curr, | |
2741 | struct lockdep_map *lock, unsigned long ip) | |
2742 | { | |
2743 | struct held_lock *hlock, *prev_hlock; | |
2744 | unsigned int depth; | |
2745 | int i; | |
2746 | ||
2747 | /* | |
2748 | * Check whether the lock exists in the current stack | |
2749 | * of held locks: | |
2750 | */ | |
2751 | depth = curr->lockdep_depth; | |
2752 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2753 | return 0; | |
2754 | ||
2755 | prev_hlock = NULL; | |
2756 | for (i = depth-1; i >= 0; i--) { | |
2757 | hlock = curr->held_locks + i; | |
2758 | /* | |
2759 | * We must not cross into another context: | |
2760 | */ | |
2761 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2762 | break; | |
2763 | if (hlock->instance == lock) | |
2764 | goto found_it; | |
2765 | prev_hlock = hlock; | |
2766 | } | |
2767 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2768 | ||
2769 | found_it: | |
f20786ff PZ |
2770 | lock_release_holdtime(hlock); |
2771 | ||
fbb9ce95 IM |
2772 | /* |
2773 | * We have the right lock to unlock, 'hlock' points to it. | |
2774 | * Now we remove it from the stack, and add back the other | |
2775 | * entries (if any), recalculating the hash along the way: | |
2776 | */ | |
2777 | curr->lockdep_depth = i; | |
2778 | curr->curr_chain_key = hlock->prev_chain_key; | |
2779 | ||
2780 | for (i++; i < depth; i++) { | |
2781 | hlock = curr->held_locks + i; | |
2782 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2783 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 2784 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2785 | hlock->nest_lock, hlock->acquire_ip)) |
fbb9ce95 IM |
2786 | return 0; |
2787 | } | |
2788 | ||
2789 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2790 | return 0; | |
2791 | return 1; | |
2792 | } | |
2793 | ||
2794 | /* | |
2795 | * Remove the lock to the list of currently held locks - this gets | |
2796 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2797 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2798 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2799 | */ | |
2800 | static int lock_release_nested(struct task_struct *curr, | |
2801 | struct lockdep_map *lock, unsigned long ip) | |
2802 | { | |
2803 | struct held_lock *hlock; | |
2804 | unsigned int depth; | |
2805 | ||
2806 | /* | |
2807 | * Pop off the top of the lock stack: | |
2808 | */ | |
2809 | depth = curr->lockdep_depth - 1; | |
2810 | hlock = curr->held_locks + depth; | |
2811 | ||
2812 | /* | |
2813 | * Is the unlock non-nested: | |
2814 | */ | |
2815 | if (hlock->instance != lock) | |
2816 | return lock_release_non_nested(curr, lock, ip); | |
2817 | curr->lockdep_depth--; | |
2818 | ||
2819 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2820 | return 0; | |
2821 | ||
2822 | curr->curr_chain_key = hlock->prev_chain_key; | |
2823 | ||
f20786ff PZ |
2824 | lock_release_holdtime(hlock); |
2825 | ||
fbb9ce95 IM |
2826 | #ifdef CONFIG_DEBUG_LOCKDEP |
2827 | hlock->prev_chain_key = 0; | |
f82b217e | 2828 | hlock->class_idx = 0; |
fbb9ce95 IM |
2829 | hlock->acquire_ip = 0; |
2830 | hlock->irq_context = 0; | |
2831 | #endif | |
2832 | return 1; | |
2833 | } | |
2834 | ||
2835 | /* | |
2836 | * Remove the lock to the list of currently held locks - this gets | |
2837 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2838 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2839 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2840 | */ | |
2841 | static void | |
2842 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2843 | { | |
2844 | struct task_struct *curr = current; | |
2845 | ||
2846 | if (!check_unlock(curr, lock, ip)) | |
2847 | return; | |
2848 | ||
2849 | if (nested) { | |
2850 | if (!lock_release_nested(curr, lock, ip)) | |
2851 | return; | |
2852 | } else { | |
2853 | if (!lock_release_non_nested(curr, lock, ip)) | |
2854 | return; | |
2855 | } | |
2856 | ||
2857 | check_chain_key(curr); | |
2858 | } | |
2859 | ||
2860 | /* | |
2861 | * Check whether we follow the irq-flags state precisely: | |
2862 | */ | |
1d09daa5 | 2863 | static void check_flags(unsigned long flags) |
fbb9ce95 | 2864 | { |
992860e9 IM |
2865 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
2866 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
2867 | if (!debug_locks) |
2868 | return; | |
2869 | ||
5f9fa8a6 IM |
2870 | if (irqs_disabled_flags(flags)) { |
2871 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
2872 | printk("possible reason: unannotated irqs-off.\n"); | |
2873 | } | |
2874 | } else { | |
2875 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
2876 | printk("possible reason: unannotated irqs-on.\n"); | |
2877 | } | |
2878 | } | |
fbb9ce95 IM |
2879 | |
2880 | /* | |
2881 | * We dont accurately track softirq state in e.g. | |
2882 | * hardirq contexts (such as on 4KSTACKS), so only | |
2883 | * check if not in hardirq contexts: | |
2884 | */ | |
2885 | if (!hardirq_count()) { | |
2886 | if (softirq_count()) | |
2887 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
2888 | else | |
2889 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
2890 | } | |
2891 | ||
2892 | if (!debug_locks) | |
2893 | print_irqtrace_events(current); | |
2894 | #endif | |
2895 | } | |
2896 | ||
00ef9f73 PZ |
2897 | void lock_set_class(struct lockdep_map *lock, const char *name, |
2898 | struct lock_class_key *key, unsigned int subclass, | |
2899 | unsigned long ip) | |
64aa348e PZ |
2900 | { |
2901 | unsigned long flags; | |
2902 | ||
2903 | if (unlikely(current->lockdep_recursion)) | |
2904 | return; | |
2905 | ||
2906 | raw_local_irq_save(flags); | |
2907 | current->lockdep_recursion = 1; | |
2908 | check_flags(flags); | |
00ef9f73 | 2909 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
2910 | check_chain_key(current); |
2911 | current->lockdep_recursion = 0; | |
2912 | raw_local_irq_restore(flags); | |
2913 | } | |
00ef9f73 | 2914 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 2915 | |
fbb9ce95 IM |
2916 | /* |
2917 | * We are not always called with irqs disabled - do that here, | |
2918 | * and also avoid lockdep recursion: | |
2919 | */ | |
1d09daa5 | 2920 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
2921 | int trylock, int read, int check, |
2922 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
2923 | { |
2924 | unsigned long flags; | |
2925 | ||
2926 | if (unlikely(current->lockdep_recursion)) | |
2927 | return; | |
2928 | ||
2929 | raw_local_irq_save(flags); | |
2930 | check_flags(flags); | |
2931 | ||
2932 | current->lockdep_recursion = 1; | |
2933 | __lock_acquire(lock, subclass, trylock, read, check, | |
7531e2f3 | 2934 | irqs_disabled_flags(flags), nest_lock, ip); |
fbb9ce95 IM |
2935 | current->lockdep_recursion = 0; |
2936 | raw_local_irq_restore(flags); | |
2937 | } | |
fbb9ce95 IM |
2938 | EXPORT_SYMBOL_GPL(lock_acquire); |
2939 | ||
1d09daa5 | 2940 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 2941 | unsigned long ip) |
fbb9ce95 IM |
2942 | { |
2943 | unsigned long flags; | |
2944 | ||
2945 | if (unlikely(current->lockdep_recursion)) | |
2946 | return; | |
2947 | ||
2948 | raw_local_irq_save(flags); | |
2949 | check_flags(flags); | |
2950 | current->lockdep_recursion = 1; | |
2951 | __lock_release(lock, nested, ip); | |
2952 | current->lockdep_recursion = 0; | |
2953 | raw_local_irq_restore(flags); | |
2954 | } | |
fbb9ce95 IM |
2955 | EXPORT_SYMBOL_GPL(lock_release); |
2956 | ||
cf40bd16 NP |
2957 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
2958 | { | |
2959 | current->lockdep_reclaim_gfp = gfp_mask; | |
2960 | } | |
2961 | ||
2962 | void lockdep_clear_current_reclaim_state(void) | |
2963 | { | |
2964 | current->lockdep_reclaim_gfp = 0; | |
2965 | } | |
2966 | ||
f20786ff PZ |
2967 | #ifdef CONFIG_LOCK_STAT |
2968 | static int | |
2969 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2970 | unsigned long ip) | |
2971 | { | |
2972 | if (!debug_locks_off()) | |
2973 | return 0; | |
2974 | if (debug_locks_silent) | |
2975 | return 0; | |
2976 | ||
2977 | printk("\n=================================\n"); | |
2978 | printk( "[ BUG: bad contention detected! ]\n"); | |
2979 | printk( "---------------------------------\n"); | |
2980 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 2981 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
2982 | print_lockdep_cache(lock); |
2983 | printk(") at:\n"); | |
2984 | print_ip_sym(ip); | |
2985 | printk("but there are no locks held!\n"); | |
2986 | printk("\nother info that might help us debug this:\n"); | |
2987 | lockdep_print_held_locks(curr); | |
2988 | ||
2989 | printk("\nstack backtrace:\n"); | |
2990 | dump_stack(); | |
2991 | ||
2992 | return 0; | |
2993 | } | |
2994 | ||
2995 | static void | |
2996 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
2997 | { | |
2998 | struct task_struct *curr = current; | |
2999 | struct held_lock *hlock, *prev_hlock; | |
3000 | struct lock_class_stats *stats; | |
3001 | unsigned int depth; | |
c7e78cff | 3002 | int i, contention_point, contending_point; |
f20786ff PZ |
3003 | |
3004 | depth = curr->lockdep_depth; | |
3005 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3006 | return; | |
3007 | ||
3008 | prev_hlock = NULL; | |
3009 | for (i = depth-1; i >= 0; i--) { | |
3010 | hlock = curr->held_locks + i; | |
3011 | /* | |
3012 | * We must not cross into another context: | |
3013 | */ | |
3014 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3015 | break; | |
3016 | if (hlock->instance == lock) | |
3017 | goto found_it; | |
3018 | prev_hlock = hlock; | |
3019 | } | |
3020 | print_lock_contention_bug(curr, lock, ip); | |
3021 | return; | |
3022 | ||
3023 | found_it: | |
3024 | hlock->waittime_stamp = sched_clock(); | |
3025 | ||
c7e78cff PZ |
3026 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3027 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3028 | lock->ip); | |
f20786ff | 3029 | |
f82b217e | 3030 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3031 | if (contention_point < LOCKSTAT_POINTS) |
3032 | stats->contention_point[contention_point]++; | |
3033 | if (contending_point < LOCKSTAT_POINTS) | |
3034 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3035 | if (lock->cpu != smp_processor_id()) |
3036 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3037 | put_lock_stats(stats); |
3038 | } | |
3039 | ||
3040 | static void | |
c7e78cff | 3041 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3042 | { |
3043 | struct task_struct *curr = current; | |
3044 | struct held_lock *hlock, *prev_hlock; | |
3045 | struct lock_class_stats *stats; | |
3046 | unsigned int depth; | |
3047 | u64 now; | |
96645678 PZ |
3048 | s64 waittime = 0; |
3049 | int i, cpu; | |
f20786ff PZ |
3050 | |
3051 | depth = curr->lockdep_depth; | |
3052 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3053 | return; | |
3054 | ||
3055 | prev_hlock = NULL; | |
3056 | for (i = depth-1; i >= 0; i--) { | |
3057 | hlock = curr->held_locks + i; | |
3058 | /* | |
3059 | * We must not cross into another context: | |
3060 | */ | |
3061 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3062 | break; | |
3063 | if (hlock->instance == lock) | |
3064 | goto found_it; | |
3065 | prev_hlock = hlock; | |
3066 | } | |
3067 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3068 | return; | |
3069 | ||
3070 | found_it: | |
96645678 PZ |
3071 | cpu = smp_processor_id(); |
3072 | if (hlock->waittime_stamp) { | |
3073 | now = sched_clock(); | |
3074 | waittime = now - hlock->waittime_stamp; | |
3075 | hlock->holdtime_stamp = now; | |
3076 | } | |
f20786ff | 3077 | |
f82b217e | 3078 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3079 | if (waittime) { |
3080 | if (hlock->read) | |
3081 | lock_time_inc(&stats->read_waittime, waittime); | |
3082 | else | |
3083 | lock_time_inc(&stats->write_waittime, waittime); | |
3084 | } | |
3085 | if (lock->cpu != cpu) | |
3086 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3087 | put_lock_stats(stats); |
96645678 PZ |
3088 | |
3089 | lock->cpu = cpu; | |
c7e78cff | 3090 | lock->ip = ip; |
f20786ff PZ |
3091 | } |
3092 | ||
3093 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3094 | { | |
3095 | unsigned long flags; | |
3096 | ||
3097 | if (unlikely(!lock_stat)) | |
3098 | return; | |
3099 | ||
3100 | if (unlikely(current->lockdep_recursion)) | |
3101 | return; | |
3102 | ||
3103 | raw_local_irq_save(flags); | |
3104 | check_flags(flags); | |
3105 | current->lockdep_recursion = 1; | |
3106 | __lock_contended(lock, ip); | |
3107 | current->lockdep_recursion = 0; | |
3108 | raw_local_irq_restore(flags); | |
3109 | } | |
3110 | EXPORT_SYMBOL_GPL(lock_contended); | |
3111 | ||
c7e78cff | 3112 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3113 | { |
3114 | unsigned long flags; | |
3115 | ||
3116 | if (unlikely(!lock_stat)) | |
3117 | return; | |
3118 | ||
3119 | if (unlikely(current->lockdep_recursion)) | |
3120 | return; | |
3121 | ||
3122 | raw_local_irq_save(flags); | |
3123 | check_flags(flags); | |
3124 | current->lockdep_recursion = 1; | |
c7e78cff | 3125 | __lock_acquired(lock, ip); |
f20786ff PZ |
3126 | current->lockdep_recursion = 0; |
3127 | raw_local_irq_restore(flags); | |
3128 | } | |
3129 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3130 | #endif | |
3131 | ||
fbb9ce95 IM |
3132 | /* |
3133 | * Used by the testsuite, sanitize the validator state | |
3134 | * after a simulated failure: | |
3135 | */ | |
3136 | ||
3137 | void lockdep_reset(void) | |
3138 | { | |
3139 | unsigned long flags; | |
23d95a03 | 3140 | int i; |
fbb9ce95 IM |
3141 | |
3142 | raw_local_irq_save(flags); | |
3143 | current->curr_chain_key = 0; | |
3144 | current->lockdep_depth = 0; | |
3145 | current->lockdep_recursion = 0; | |
3146 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3147 | nr_hardirq_chains = 0; | |
3148 | nr_softirq_chains = 0; | |
3149 | nr_process_chains = 0; | |
3150 | debug_locks = 1; | |
23d95a03 IM |
3151 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3152 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3153 | raw_local_irq_restore(flags); |
3154 | } | |
3155 | ||
3156 | static void zap_class(struct lock_class *class) | |
3157 | { | |
3158 | int i; | |
3159 | ||
3160 | /* | |
3161 | * Remove all dependencies this lock is | |
3162 | * involved in: | |
3163 | */ | |
3164 | for (i = 0; i < nr_list_entries; i++) { | |
3165 | if (list_entries[i].class == class) | |
3166 | list_del_rcu(&list_entries[i].entry); | |
3167 | } | |
3168 | /* | |
3169 | * Unhash the class and remove it from the all_lock_classes list: | |
3170 | */ | |
3171 | list_del_rcu(&class->hash_entry); | |
3172 | list_del_rcu(&class->lock_entry); | |
3173 | ||
8bfe0298 | 3174 | class->key = NULL; |
fbb9ce95 IM |
3175 | } |
3176 | ||
fabe874a | 3177 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3178 | { |
3179 | return addr >= start && addr < start + size; | |
3180 | } | |
3181 | ||
3182 | void lockdep_free_key_range(void *start, unsigned long size) | |
3183 | { | |
3184 | struct lock_class *class, *next; | |
3185 | struct list_head *head; | |
3186 | unsigned long flags; | |
3187 | int i; | |
5a26db5b | 3188 | int locked; |
fbb9ce95 IM |
3189 | |
3190 | raw_local_irq_save(flags); | |
5a26db5b | 3191 | locked = graph_lock(); |
fbb9ce95 IM |
3192 | |
3193 | /* | |
3194 | * Unhash all classes that were created by this module: | |
3195 | */ | |
3196 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3197 | head = classhash_table + i; | |
3198 | if (list_empty(head)) | |
3199 | continue; | |
fabe874a | 3200 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3201 | if (within(class->key, start, size)) |
3202 | zap_class(class); | |
fabe874a AV |
3203 | else if (within(class->name, start, size)) |
3204 | zap_class(class); | |
3205 | } | |
fbb9ce95 IM |
3206 | } |
3207 | ||
5a26db5b NP |
3208 | if (locked) |
3209 | graph_unlock(); | |
fbb9ce95 IM |
3210 | raw_local_irq_restore(flags); |
3211 | } | |
3212 | ||
3213 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3214 | { | |
d6d897ce | 3215 | struct lock_class *class, *next; |
fbb9ce95 IM |
3216 | struct list_head *head; |
3217 | unsigned long flags; | |
3218 | int i, j; | |
5a26db5b | 3219 | int locked; |
fbb9ce95 IM |
3220 | |
3221 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3222 | |
3223 | /* | |
d6d897ce IM |
3224 | * Remove all classes this lock might have: |
3225 | */ | |
3226 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3227 | /* | |
3228 | * If the class exists we look it up and zap it: | |
3229 | */ | |
3230 | class = look_up_lock_class(lock, j); | |
3231 | if (class) | |
3232 | zap_class(class); | |
3233 | } | |
3234 | /* | |
3235 | * Debug check: in the end all mapped classes should | |
3236 | * be gone. | |
fbb9ce95 | 3237 | */ |
5a26db5b | 3238 | locked = graph_lock(); |
fbb9ce95 IM |
3239 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3240 | head = classhash_table + i; | |
3241 | if (list_empty(head)) | |
3242 | continue; | |
3243 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3244 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3245 | if (debug_locks_off_graph_unlock()) |
3246 | WARN_ON(1); | |
d6d897ce | 3247 | goto out_restore; |
fbb9ce95 IM |
3248 | } |
3249 | } | |
3250 | } | |
5a26db5b NP |
3251 | if (locked) |
3252 | graph_unlock(); | |
d6d897ce IM |
3253 | |
3254 | out_restore: | |
fbb9ce95 IM |
3255 | raw_local_irq_restore(flags); |
3256 | } | |
3257 | ||
1499993c | 3258 | void lockdep_init(void) |
fbb9ce95 IM |
3259 | { |
3260 | int i; | |
3261 | ||
3262 | /* | |
3263 | * Some architectures have their own start_kernel() | |
3264 | * code which calls lockdep_init(), while we also | |
3265 | * call lockdep_init() from the start_kernel() itself, | |
3266 | * and we want to initialize the hashes only once: | |
3267 | */ | |
3268 | if (lockdep_initialized) | |
3269 | return; | |
3270 | ||
3271 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3272 | INIT_LIST_HEAD(classhash_table + i); | |
3273 | ||
3274 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3275 | INIT_LIST_HEAD(chainhash_table + i); | |
3276 | ||
3277 | lockdep_initialized = 1; | |
3278 | } | |
3279 | ||
3280 | void __init lockdep_info(void) | |
3281 | { | |
3282 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3283 | ||
b0788caf | 3284 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3285 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3286 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3287 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3288 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3289 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3290 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3291 | ||
3292 | printk(" memory used by lock dependency info: %lu kB\n", | |
3293 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3294 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3295 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3296 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
3297 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
3298 | ||
3299 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3300 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3301 | ||
3302 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3303 | if (lockdep_init_error) { |
3304 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3305 | printk("Call stack leading to lockdep invocation was:\n"); | |
3306 | print_stack_trace(&lockdep_init_trace, 0); | |
3307 | } | |
fbb9ce95 IM |
3308 | #endif |
3309 | } | |
3310 | ||
fbb9ce95 IM |
3311 | static void |
3312 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3313 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3314 | { |
3315 | if (!debug_locks_off()) | |
3316 | return; | |
3317 | if (debug_locks_silent) | |
3318 | return; | |
3319 | ||
3320 | printk("\n=========================\n"); | |
3321 | printk( "[ BUG: held lock freed! ]\n"); | |
3322 | printk( "-------------------------\n"); | |
3323 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3324 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3325 | print_lock(hlock); |
fbb9ce95 IM |
3326 | lockdep_print_held_locks(curr); |
3327 | ||
3328 | printk("\nstack backtrace:\n"); | |
3329 | dump_stack(); | |
3330 | } | |
3331 | ||
54561783 ON |
3332 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3333 | const void* lock_from, unsigned long lock_len) | |
3334 | { | |
3335 | return lock_from + lock_len <= mem_from || | |
3336 | mem_from + mem_len <= lock_from; | |
3337 | } | |
3338 | ||
fbb9ce95 IM |
3339 | /* |
3340 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3341 | * is destroyed or reinitialized - this code checks whether there is | |
3342 | * any held lock in the memory range of <from> to <to>: | |
3343 | */ | |
3344 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3345 | { | |
fbb9ce95 IM |
3346 | struct task_struct *curr = current; |
3347 | struct held_lock *hlock; | |
3348 | unsigned long flags; | |
3349 | int i; | |
3350 | ||
3351 | if (unlikely(!debug_locks)) | |
3352 | return; | |
3353 | ||
3354 | local_irq_save(flags); | |
3355 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3356 | hlock = curr->held_locks + i; | |
3357 | ||
54561783 ON |
3358 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3359 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3360 | continue; |
3361 | ||
54561783 | 3362 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3363 | break; |
3364 | } | |
3365 | local_irq_restore(flags); | |
3366 | } | |
ed07536e | 3367 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3368 | |
3369 | static void print_held_locks_bug(struct task_struct *curr) | |
3370 | { | |
3371 | if (!debug_locks_off()) | |
3372 | return; | |
3373 | if (debug_locks_silent) | |
3374 | return; | |
3375 | ||
3376 | printk("\n=====================================\n"); | |
3377 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3378 | printk( "-------------------------------------\n"); | |
3379 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3380 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3381 | lockdep_print_held_locks(curr); |
3382 | ||
3383 | printk("\nstack backtrace:\n"); | |
3384 | dump_stack(); | |
3385 | } | |
3386 | ||
3387 | void debug_check_no_locks_held(struct task_struct *task) | |
3388 | { | |
3389 | if (unlikely(task->lockdep_depth > 0)) | |
3390 | print_held_locks_bug(task); | |
3391 | } | |
3392 | ||
3393 | void debug_show_all_locks(void) | |
3394 | { | |
3395 | struct task_struct *g, *p; | |
3396 | int count = 10; | |
3397 | int unlock = 1; | |
3398 | ||
9c35dd7f JP |
3399 | if (unlikely(!debug_locks)) { |
3400 | printk("INFO: lockdep is turned off.\n"); | |
3401 | return; | |
3402 | } | |
fbb9ce95 IM |
3403 | printk("\nShowing all locks held in the system:\n"); |
3404 | ||
3405 | /* | |
3406 | * Here we try to get the tasklist_lock as hard as possible, | |
3407 | * if not successful after 2 seconds we ignore it (but keep | |
3408 | * trying). This is to enable a debug printout even if a | |
3409 | * tasklist_lock-holding task deadlocks or crashes. | |
3410 | */ | |
3411 | retry: | |
3412 | if (!read_trylock(&tasklist_lock)) { | |
3413 | if (count == 10) | |
3414 | printk("hm, tasklist_lock locked, retrying... "); | |
3415 | if (count) { | |
3416 | count--; | |
3417 | printk(" #%d", 10-count); | |
3418 | mdelay(200); | |
3419 | goto retry; | |
3420 | } | |
3421 | printk(" ignoring it.\n"); | |
3422 | unlock = 0; | |
46fec7ac | 3423 | } else { |
3424 | if (count != 10) | |
3425 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3426 | } |
fbb9ce95 IM |
3427 | |
3428 | do_each_thread(g, p) { | |
85684873 IM |
3429 | /* |
3430 | * It's not reliable to print a task's held locks | |
3431 | * if it's not sleeping (or if it's not the current | |
3432 | * task): | |
3433 | */ | |
3434 | if (p->state == TASK_RUNNING && p != current) | |
3435 | continue; | |
fbb9ce95 IM |
3436 | if (p->lockdep_depth) |
3437 | lockdep_print_held_locks(p); | |
3438 | if (!unlock) | |
3439 | if (read_trylock(&tasklist_lock)) | |
3440 | unlock = 1; | |
3441 | } while_each_thread(g, p); | |
3442 | ||
3443 | printk("\n"); | |
3444 | printk("=============================================\n\n"); | |
3445 | ||
3446 | if (unlock) | |
3447 | read_unlock(&tasklist_lock); | |
3448 | } | |
fbb9ce95 IM |
3449 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3450 | ||
82a1fcb9 IM |
3451 | /* |
3452 | * Careful: only use this function if you are sure that | |
3453 | * the task cannot run in parallel! | |
3454 | */ | |
3455 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3456 | { |
9c35dd7f JP |
3457 | if (unlikely(!debug_locks)) { |
3458 | printk("INFO: lockdep is turned off.\n"); | |
3459 | return; | |
3460 | } | |
fbb9ce95 IM |
3461 | lockdep_print_held_locks(task); |
3462 | } | |
82a1fcb9 IM |
3463 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3464 | ||
3465 | void debug_show_held_locks(struct task_struct *task) | |
3466 | { | |
3467 | __debug_show_held_locks(task); | |
3468 | } | |
fbb9ce95 | 3469 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3470 | |
3471 | void lockdep_sys_exit(void) | |
3472 | { | |
3473 | struct task_struct *curr = current; | |
3474 | ||
3475 | if (unlikely(curr->lockdep_depth)) { | |
3476 | if (!debug_locks_off()) | |
3477 | return; | |
3478 | printk("\n================================================\n"); | |
3479 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3480 | printk( "------------------------------------------------\n"); | |
3481 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3482 | curr->comm, curr->pid); | |
3483 | lockdep_print_held_locks(curr); | |
3484 | } | |
3485 | } |