Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
28 | #include <linux/mutex.h> | |
29 | #include <linux/sched.h> | |
30 | #include <linux/delay.h> | |
31 | #include <linux/module.h> | |
32 | #include <linux/proc_fs.h> | |
33 | #include <linux/seq_file.h> | |
34 | #include <linux/spinlock.h> | |
35 | #include <linux/kallsyms.h> | |
36 | #include <linux/interrupt.h> | |
37 | #include <linux/stacktrace.h> | |
38 | #include <linux/debug_locks.h> | |
39 | #include <linux/irqflags.h> | |
99de055a | 40 | #include <linux/utsname.h> |
4b32d0a4 | 41 | #include <linux/hash.h> |
81d68a96 | 42 | #include <linux/ftrace.h> |
fbb9ce95 IM |
43 | |
44 | #include <asm/sections.h> | |
45 | ||
46 | #include "lockdep_internals.h" | |
47 | ||
f20786ff PZ |
48 | #ifdef CONFIG_PROVE_LOCKING |
49 | int prove_locking = 1; | |
50 | module_param(prove_locking, int, 0644); | |
51 | #else | |
52 | #define prove_locking 0 | |
53 | #endif | |
54 | ||
55 | #ifdef CONFIG_LOCK_STAT | |
56 | int lock_stat = 1; | |
57 | module_param(lock_stat, int, 0644); | |
58 | #else | |
59 | #define lock_stat 0 | |
60 | #endif | |
61 | ||
fbb9ce95 | 62 | /* |
74c383f1 IM |
63 | * lockdep_lock: protects the lockdep graph, the hashes and the |
64 | * class/list/hash allocators. | |
fbb9ce95 IM |
65 | * |
66 | * This is one of the rare exceptions where it's justified | |
67 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 68 | * code to recurse back into the lockdep code... |
fbb9ce95 | 69 | */ |
74c383f1 IM |
70 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
71 | ||
72 | static int graph_lock(void) | |
73 | { | |
74 | __raw_spin_lock(&lockdep_lock); | |
75 | /* | |
76 | * Make sure that if another CPU detected a bug while | |
77 | * walking the graph we dont change it (while the other | |
78 | * CPU is busy printing out stuff with the graph lock | |
79 | * dropped already) | |
80 | */ | |
81 | if (!debug_locks) { | |
82 | __raw_spin_unlock(&lockdep_lock); | |
83 | return 0; | |
84 | } | |
bb065afb SR |
85 | /* prevent any recursions within lockdep from causing deadlocks */ |
86 | current->lockdep_recursion++; | |
74c383f1 IM |
87 | return 1; |
88 | } | |
89 | ||
90 | static inline int graph_unlock(void) | |
91 | { | |
381a2292 JP |
92 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
93 | return DEBUG_LOCKS_WARN_ON(1); | |
94 | ||
bb065afb | 95 | current->lockdep_recursion--; |
74c383f1 IM |
96 | __raw_spin_unlock(&lockdep_lock); |
97 | return 0; | |
98 | } | |
99 | ||
100 | /* | |
101 | * Turn lock debugging off and return with 0 if it was off already, | |
102 | * and also release the graph lock: | |
103 | */ | |
104 | static inline int debug_locks_off_graph_unlock(void) | |
105 | { | |
106 | int ret = debug_locks_off(); | |
107 | ||
108 | __raw_spin_unlock(&lockdep_lock); | |
109 | ||
110 | return ret; | |
111 | } | |
fbb9ce95 IM |
112 | |
113 | static int lockdep_initialized; | |
114 | ||
115 | unsigned long nr_list_entries; | |
116 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; | |
117 | ||
fbb9ce95 IM |
118 | /* |
119 | * All data structures here are protected by the global debug_lock. | |
120 | * | |
121 | * Mutex key structs only get allocated, once during bootup, and never | |
122 | * get freed - this significantly simplifies the debugging code. | |
123 | */ | |
124 | unsigned long nr_lock_classes; | |
125 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
126 | ||
f82b217e DJ |
127 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
128 | { | |
129 | if (!hlock->class_idx) { | |
130 | DEBUG_LOCKS_WARN_ON(1); | |
131 | return NULL; | |
132 | } | |
133 | return lock_classes + hlock->class_idx - 1; | |
134 | } | |
135 | ||
f20786ff PZ |
136 | #ifdef CONFIG_LOCK_STAT |
137 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); | |
138 | ||
139 | static int lock_contention_point(struct lock_class *class, unsigned long ip) | |
140 | { | |
141 | int i; | |
142 | ||
143 | for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) { | |
144 | if (class->contention_point[i] == 0) { | |
145 | class->contention_point[i] = ip; | |
146 | break; | |
147 | } | |
148 | if (class->contention_point[i] == ip) | |
149 | break; | |
150 | } | |
151 | ||
152 | return i; | |
153 | } | |
154 | ||
155 | static void lock_time_inc(struct lock_time *lt, s64 time) | |
156 | { | |
157 | if (time > lt->max) | |
158 | lt->max = time; | |
159 | ||
160 | if (time < lt->min || !lt->min) | |
161 | lt->min = time; | |
162 | ||
163 | lt->total += time; | |
164 | lt->nr++; | |
165 | } | |
166 | ||
c46261de PZ |
167 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
168 | { | |
169 | dst->min += src->min; | |
170 | dst->max += src->max; | |
171 | dst->total += src->total; | |
172 | dst->nr += src->nr; | |
173 | } | |
174 | ||
175 | struct lock_class_stats lock_stats(struct lock_class *class) | |
176 | { | |
177 | struct lock_class_stats stats; | |
178 | int cpu, i; | |
179 | ||
180 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
181 | for_each_possible_cpu(cpu) { | |
182 | struct lock_class_stats *pcs = | |
183 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
184 | ||
185 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
186 | stats.contention_point[i] += pcs->contention_point[i]; | |
187 | ||
188 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); | |
189 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
190 | ||
191 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
192 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
193 | |
194 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
195 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
196 | } |
197 | ||
198 | return stats; | |
199 | } | |
200 | ||
201 | void clear_lock_stats(struct lock_class *class) | |
202 | { | |
203 | int cpu; | |
204 | ||
205 | for_each_possible_cpu(cpu) { | |
206 | struct lock_class_stats *cpu_stats = | |
207 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
208 | ||
209 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
210 | } | |
211 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
212 | } | |
213 | ||
f20786ff PZ |
214 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
215 | { | |
216 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
217 | } | |
218 | ||
219 | static void put_lock_stats(struct lock_class_stats *stats) | |
220 | { | |
221 | put_cpu_var(lock_stats); | |
222 | } | |
223 | ||
224 | static void lock_release_holdtime(struct held_lock *hlock) | |
225 | { | |
226 | struct lock_class_stats *stats; | |
227 | s64 holdtime; | |
228 | ||
229 | if (!lock_stat) | |
230 | return; | |
231 | ||
232 | holdtime = sched_clock() - hlock->holdtime_stamp; | |
233 | ||
f82b217e | 234 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
235 | if (hlock->read) |
236 | lock_time_inc(&stats->read_holdtime, holdtime); | |
237 | else | |
238 | lock_time_inc(&stats->write_holdtime, holdtime); | |
239 | put_lock_stats(stats); | |
240 | } | |
241 | #else | |
242 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
243 | { | |
244 | } | |
245 | #endif | |
246 | ||
fbb9ce95 IM |
247 | /* |
248 | * We keep a global list of all lock classes. The list only grows, | |
249 | * never shrinks. The list is only accessed with the lockdep | |
250 | * spinlock lock held. | |
251 | */ | |
252 | LIST_HEAD(all_lock_classes); | |
253 | ||
254 | /* | |
255 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
256 | */ | |
257 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
258 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 259 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
260 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
261 | ||
262 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
263 | ||
fbb9ce95 IM |
264 | /* |
265 | * We put the lock dependency chains into a hash-table as well, to cache | |
266 | * their existence: | |
267 | */ | |
268 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
269 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 270 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
271 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
272 | ||
273 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
274 | ||
275 | /* | |
276 | * The hash key of the lock dependency chains is a hash itself too: | |
277 | * it's a hash of all locks taken up to that lock, including that lock. | |
278 | * It's a 64-bit hash, because it's important for the keys to be | |
279 | * unique. | |
280 | */ | |
281 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
282 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
283 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
284 | (key2)) |
285 | ||
1d09daa5 | 286 | void lockdep_off(void) |
fbb9ce95 IM |
287 | { |
288 | current->lockdep_recursion++; | |
289 | } | |
290 | ||
291 | EXPORT_SYMBOL(lockdep_off); | |
292 | ||
1d09daa5 | 293 | void lockdep_on(void) |
fbb9ce95 IM |
294 | { |
295 | current->lockdep_recursion--; | |
296 | } | |
297 | ||
298 | EXPORT_SYMBOL(lockdep_on); | |
299 | ||
fbb9ce95 IM |
300 | /* |
301 | * Debugging switches: | |
302 | */ | |
303 | ||
304 | #define VERBOSE 0 | |
33e94e96 | 305 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
306 | |
307 | #if VERBOSE | |
308 | # define HARDIRQ_VERBOSE 1 | |
309 | # define SOFTIRQ_VERBOSE 1 | |
310 | #else | |
311 | # define HARDIRQ_VERBOSE 0 | |
312 | # define SOFTIRQ_VERBOSE 0 | |
313 | #endif | |
314 | ||
315 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE | |
316 | /* | |
317 | * Quick filtering for interesting events: | |
318 | */ | |
319 | static int class_filter(struct lock_class *class) | |
320 | { | |
f9829cce AK |
321 | #if 0 |
322 | /* Example */ | |
fbb9ce95 | 323 | if (class->name_version == 1 && |
f9829cce | 324 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
325 | return 1; |
326 | if (class->name_version == 1 && | |
f9829cce | 327 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 328 | return 1; |
f9829cce | 329 | #endif |
a6640897 IM |
330 | /* Filter everything else. 1 would be to allow everything else */ |
331 | return 0; | |
fbb9ce95 IM |
332 | } |
333 | #endif | |
334 | ||
335 | static int verbose(struct lock_class *class) | |
336 | { | |
337 | #if VERBOSE | |
338 | return class_filter(class); | |
339 | #endif | |
340 | return 0; | |
341 | } | |
342 | ||
fbb9ce95 IM |
343 | /* |
344 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 345 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
346 | */ |
347 | unsigned long nr_stack_trace_entries; | |
348 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
349 | ||
350 | static int save_trace(struct stack_trace *trace) | |
351 | { | |
352 | trace->nr_entries = 0; | |
353 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
354 | trace->entries = stack_trace + nr_stack_trace_entries; | |
355 | ||
5a1b3999 | 356 | trace->skip = 3; |
5a1b3999 | 357 | |
ab1b6f03 | 358 | save_stack_trace(trace); |
fbb9ce95 IM |
359 | |
360 | trace->max_entries = trace->nr_entries; | |
361 | ||
362 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
363 | |
364 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
365 | if (!debug_locks_off_graph_unlock()) |
366 | return 0; | |
367 | ||
368 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
369 | printk("turning off the locking correctness validator.\n"); | |
370 | dump_stack(); | |
371 | ||
fbb9ce95 IM |
372 | return 0; |
373 | } | |
374 | ||
375 | return 1; | |
376 | } | |
377 | ||
378 | unsigned int nr_hardirq_chains; | |
379 | unsigned int nr_softirq_chains; | |
380 | unsigned int nr_process_chains; | |
381 | unsigned int max_lockdep_depth; | |
382 | unsigned int max_recursion_depth; | |
383 | ||
419ca3f1 DM |
384 | static unsigned int lockdep_dependency_gen_id; |
385 | ||
386 | static bool lockdep_dependency_visit(struct lock_class *source, | |
387 | unsigned int depth) | |
388 | { | |
389 | if (!depth) | |
390 | lockdep_dependency_gen_id++; | |
391 | if (source->dep_gen_id == lockdep_dependency_gen_id) | |
392 | return true; | |
393 | source->dep_gen_id = lockdep_dependency_gen_id; | |
394 | return false; | |
395 | } | |
396 | ||
fbb9ce95 IM |
397 | #ifdef CONFIG_DEBUG_LOCKDEP |
398 | /* | |
399 | * We cannot printk in early bootup code. Not even early_printk() | |
400 | * might work. So we mark any initialization errors and printk | |
401 | * about it later on, in lockdep_info(). | |
402 | */ | |
403 | static int lockdep_init_error; | |
c71063c9 JB |
404 | static unsigned long lockdep_init_trace_data[20]; |
405 | static struct stack_trace lockdep_init_trace = { | |
406 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
407 | .entries = lockdep_init_trace_data, | |
408 | }; | |
fbb9ce95 IM |
409 | |
410 | /* | |
411 | * Various lockdep statistics: | |
412 | */ | |
413 | atomic_t chain_lookup_hits; | |
414 | atomic_t chain_lookup_misses; | |
415 | atomic_t hardirqs_on_events; | |
416 | atomic_t hardirqs_off_events; | |
417 | atomic_t redundant_hardirqs_on; | |
418 | atomic_t redundant_hardirqs_off; | |
419 | atomic_t softirqs_on_events; | |
420 | atomic_t softirqs_off_events; | |
421 | atomic_t redundant_softirqs_on; | |
422 | atomic_t redundant_softirqs_off; | |
423 | atomic_t nr_unused_locks; | |
424 | atomic_t nr_cyclic_checks; | |
425 | atomic_t nr_cyclic_check_recursions; | |
426 | atomic_t nr_find_usage_forwards_checks; | |
427 | atomic_t nr_find_usage_forwards_recursions; | |
428 | atomic_t nr_find_usage_backwards_checks; | |
429 | atomic_t nr_find_usage_backwards_recursions; | |
430 | # define debug_atomic_inc(ptr) atomic_inc(ptr) | |
431 | # define debug_atomic_dec(ptr) atomic_dec(ptr) | |
432 | # define debug_atomic_read(ptr) atomic_read(ptr) | |
433 | #else | |
434 | # define debug_atomic_inc(ptr) do { } while (0) | |
435 | # define debug_atomic_dec(ptr) do { } while (0) | |
436 | # define debug_atomic_read(ptr) 0 | |
437 | #endif | |
438 | ||
439 | /* | |
440 | * Locking printouts: | |
441 | */ | |
442 | ||
443 | static const char *usage_str[] = | |
444 | { | |
445 | [LOCK_USED] = "initial-use ", | |
446 | [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W", | |
447 | [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W", | |
448 | [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W", | |
449 | [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W", | |
450 | [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R", | |
451 | [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R", | |
452 | [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R", | |
453 | [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R", | |
454 | }; | |
455 | ||
456 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
457 | { | |
ffb45122 | 458 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
459 | } |
460 | ||
461 | void | |
462 | get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4) | |
463 | { | |
464 | *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.'; | |
465 | ||
466 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) | |
467 | *c1 = '+'; | |
468 | else | |
469 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) | |
470 | *c1 = '-'; | |
471 | ||
472 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) | |
473 | *c2 = '+'; | |
474 | else | |
475 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) | |
476 | *c2 = '-'; | |
477 | ||
478 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
479 | *c3 = '-'; | |
480 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { | |
481 | *c3 = '+'; | |
482 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
483 | *c3 = '?'; | |
484 | } | |
485 | ||
486 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
487 | *c4 = '-'; | |
488 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { | |
489 | *c4 = '+'; | |
490 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
491 | *c4 = '?'; | |
492 | } | |
493 | } | |
494 | ||
495 | static void print_lock_name(struct lock_class *class) | |
496 | { | |
9281acea | 497 | char str[KSYM_NAME_LEN], c1, c2, c3, c4; |
fbb9ce95 IM |
498 | const char *name; |
499 | ||
500 | get_usage_chars(class, &c1, &c2, &c3, &c4); | |
501 | ||
502 | name = class->name; | |
503 | if (!name) { | |
504 | name = __get_key_name(class->key, str); | |
505 | printk(" (%s", name); | |
506 | } else { | |
507 | printk(" (%s", name); | |
508 | if (class->name_version > 1) | |
509 | printk("#%d", class->name_version); | |
510 | if (class->subclass) | |
511 | printk("/%d", class->subclass); | |
512 | } | |
513 | printk("){%c%c%c%c}", c1, c2, c3, c4); | |
514 | } | |
515 | ||
516 | static void print_lockdep_cache(struct lockdep_map *lock) | |
517 | { | |
518 | const char *name; | |
9281acea | 519 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
520 | |
521 | name = lock->name; | |
522 | if (!name) | |
523 | name = __get_key_name(lock->key->subkeys, str); | |
524 | ||
525 | printk("%s", name); | |
526 | } | |
527 | ||
528 | static void print_lock(struct held_lock *hlock) | |
529 | { | |
f82b217e | 530 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
531 | printk(", at: "); |
532 | print_ip_sym(hlock->acquire_ip); | |
533 | } | |
534 | ||
535 | static void lockdep_print_held_locks(struct task_struct *curr) | |
536 | { | |
537 | int i, depth = curr->lockdep_depth; | |
538 | ||
539 | if (!depth) { | |
ba25f9dc | 540 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
541 | return; |
542 | } | |
543 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 544 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
545 | |
546 | for (i = 0; i < depth; i++) { | |
547 | printk(" #%d: ", i); | |
548 | print_lock(curr->held_locks + i); | |
549 | } | |
550 | } | |
fbb9ce95 IM |
551 | |
552 | static void print_lock_class_header(struct lock_class *class, int depth) | |
553 | { | |
554 | int bit; | |
555 | ||
f9829cce | 556 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
557 | print_lock_name(class); |
558 | printk(" ops: %lu", class->ops); | |
559 | printk(" {\n"); | |
560 | ||
561 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
562 | if (class->usage_mask & (1 << bit)) { | |
563 | int len = depth; | |
564 | ||
f9829cce | 565 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
566 | len += printk(" at:\n"); |
567 | print_stack_trace(class->usage_traces + bit, len); | |
568 | } | |
569 | } | |
f9829cce | 570 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 571 | |
f9829cce | 572 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
573 | print_ip_sym((unsigned long)class->key); |
574 | } | |
575 | ||
576 | /* | |
577 | * printk all lock dependencies starting at <entry>: | |
578 | */ | |
579 | static void print_lock_dependencies(struct lock_class *class, int depth) | |
580 | { | |
581 | struct lock_list *entry; | |
582 | ||
419ca3f1 DM |
583 | if (lockdep_dependency_visit(class, depth)) |
584 | return; | |
585 | ||
fbb9ce95 IM |
586 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) |
587 | return; | |
588 | ||
589 | print_lock_class_header(class, depth); | |
590 | ||
591 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
592 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
593 | return; | |
594 | ||
fbb9ce95 IM |
595 | print_lock_dependencies(entry->class, depth + 1); |
596 | ||
f9829cce | 597 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
598 | print_stack_trace(&entry->trace, 2); |
599 | printk("\n"); | |
600 | } | |
601 | } | |
602 | ||
8e18257d PZ |
603 | static void print_kernel_version(void) |
604 | { | |
605 | printk("%s %.*s\n", init_utsname()->release, | |
606 | (int)strcspn(init_utsname()->version, " "), | |
607 | init_utsname()->version); | |
608 | } | |
609 | ||
610 | static int very_verbose(struct lock_class *class) | |
611 | { | |
612 | #if VERY_VERBOSE | |
613 | return class_filter(class); | |
614 | #endif | |
615 | return 0; | |
616 | } | |
617 | ||
fbb9ce95 | 618 | /* |
8e18257d | 619 | * Is this the address of a static object: |
fbb9ce95 | 620 | */ |
8e18257d | 621 | static int static_obj(void *obj) |
fbb9ce95 | 622 | { |
8e18257d PZ |
623 | unsigned long start = (unsigned long) &_stext, |
624 | end = (unsigned long) &_end, | |
625 | addr = (unsigned long) obj; | |
626 | #ifdef CONFIG_SMP | |
627 | int i; | |
628 | #endif | |
629 | ||
fbb9ce95 | 630 | /* |
8e18257d | 631 | * static variable? |
fbb9ce95 | 632 | */ |
8e18257d PZ |
633 | if ((addr >= start) && (addr < end)) |
634 | return 1; | |
fbb9ce95 | 635 | |
8e18257d | 636 | #ifdef CONFIG_SMP |
fbb9ce95 | 637 | /* |
8e18257d | 638 | * percpu var? |
fbb9ce95 | 639 | */ |
8e18257d PZ |
640 | for_each_possible_cpu(i) { |
641 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
642 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
643 | + per_cpu_offset(i); | |
fbb9ce95 | 644 | |
8e18257d PZ |
645 | if ((addr >= start) && (addr < end)) |
646 | return 1; | |
647 | } | |
ca58abcb | 648 | #endif |
fbb9ce95 | 649 | |
8e18257d PZ |
650 | /* |
651 | * module var? | |
652 | */ | |
653 | return is_module_address(addr); | |
99de055a DJ |
654 | } |
655 | ||
fbb9ce95 | 656 | /* |
8e18257d PZ |
657 | * To make lock name printouts unique, we calculate a unique |
658 | * class->name_version generation counter: | |
fbb9ce95 | 659 | */ |
8e18257d | 660 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 661 | { |
8e18257d PZ |
662 | struct lock_class *class; |
663 | int count = 0; | |
fbb9ce95 | 664 | |
8e18257d | 665 | if (!new_class->name) |
fbb9ce95 IM |
666 | return 0; |
667 | ||
8e18257d PZ |
668 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
669 | if (new_class->key - new_class->subclass == class->key) | |
670 | return class->name_version; | |
671 | if (class->name && !strcmp(class->name, new_class->name)) | |
672 | count = max(count, class->name_version); | |
673 | } | |
fbb9ce95 | 674 | |
8e18257d | 675 | return count + 1; |
fbb9ce95 IM |
676 | } |
677 | ||
8e18257d PZ |
678 | /* |
679 | * Register a lock's class in the hash-table, if the class is not present | |
680 | * yet. Otherwise we look it up. We cache the result in the lock object | |
681 | * itself, so actual lookup of the hash should be once per lock object. | |
682 | */ | |
683 | static inline struct lock_class * | |
684 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 685 | { |
8e18257d PZ |
686 | struct lockdep_subclass_key *key; |
687 | struct list_head *hash_head; | |
688 | struct lock_class *class; | |
fbb9ce95 | 689 | |
8e18257d PZ |
690 | #ifdef CONFIG_DEBUG_LOCKDEP |
691 | /* | |
692 | * If the architecture calls into lockdep before initializing | |
693 | * the hashes then we'll warn about it later. (we cannot printk | |
694 | * right now) | |
695 | */ | |
696 | if (unlikely(!lockdep_initialized)) { | |
697 | lockdep_init(); | |
698 | lockdep_init_error = 1; | |
c71063c9 | 699 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
700 | } |
701 | #endif | |
fbb9ce95 | 702 | |
8e18257d PZ |
703 | /* |
704 | * Static locks do not have their class-keys yet - for them the key | |
705 | * is the lock object itself: | |
706 | */ | |
707 | if (unlikely(!lock->key)) | |
708 | lock->key = (void *)lock; | |
fbb9ce95 | 709 | |
8e18257d PZ |
710 | /* |
711 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
712 | * lock_class_key variable is passed in through the mutex_init() | |
713 | * (or spin_lock_init()) call - which acts as the key. For static | |
714 | * locks we use the lock object itself as the key. | |
715 | */ | |
4b32d0a4 PZ |
716 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
717 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 718 | |
8e18257d | 719 | key = lock->key->subkeys + subclass; |
ca268c69 | 720 | |
8e18257d | 721 | hash_head = classhashentry(key); |
74c383f1 | 722 | |
8e18257d PZ |
723 | /* |
724 | * We can walk the hash lockfree, because the hash only | |
725 | * grows, and we are careful when adding entries to the end: | |
726 | */ | |
4b32d0a4 PZ |
727 | list_for_each_entry(class, hash_head, hash_entry) { |
728 | if (class->key == key) { | |
729 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 730 | return class; |
4b32d0a4 PZ |
731 | } |
732 | } | |
fbb9ce95 | 733 | |
8e18257d | 734 | return NULL; |
fbb9ce95 IM |
735 | } |
736 | ||
737 | /* | |
8e18257d PZ |
738 | * Register a lock's class in the hash-table, if the class is not present |
739 | * yet. Otherwise we look it up. We cache the result in the lock object | |
740 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 741 | */ |
8e18257d PZ |
742 | static inline struct lock_class * |
743 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 744 | { |
8e18257d PZ |
745 | struct lockdep_subclass_key *key; |
746 | struct list_head *hash_head; | |
747 | struct lock_class *class; | |
748 | unsigned long flags; | |
749 | ||
750 | class = look_up_lock_class(lock, subclass); | |
751 | if (likely(class)) | |
752 | return class; | |
753 | ||
754 | /* | |
755 | * Debug-check: all keys must be persistent! | |
756 | */ | |
757 | if (!static_obj(lock->key)) { | |
758 | debug_locks_off(); | |
759 | printk("INFO: trying to register non-static key.\n"); | |
760 | printk("the code is fine but needs lockdep annotation.\n"); | |
761 | printk("turning off the locking correctness validator.\n"); | |
762 | dump_stack(); | |
763 | ||
764 | return NULL; | |
765 | } | |
766 | ||
767 | key = lock->key->subkeys + subclass; | |
768 | hash_head = classhashentry(key); | |
769 | ||
770 | raw_local_irq_save(flags); | |
771 | if (!graph_lock()) { | |
772 | raw_local_irq_restore(flags); | |
773 | return NULL; | |
774 | } | |
775 | /* | |
776 | * We have to do the hash-walk again, to avoid races | |
777 | * with another CPU: | |
778 | */ | |
779 | list_for_each_entry(class, hash_head, hash_entry) | |
780 | if (class->key == key) | |
781 | goto out_unlock_set; | |
782 | /* | |
783 | * Allocate a new key from the static array, and add it to | |
784 | * the hash: | |
785 | */ | |
786 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
787 | if (!debug_locks_off_graph_unlock()) { | |
788 | raw_local_irq_restore(flags); | |
789 | return NULL; | |
790 | } | |
791 | raw_local_irq_restore(flags); | |
792 | ||
793 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
794 | printk("turning off the locking correctness validator.\n"); | |
795 | return NULL; | |
796 | } | |
797 | class = lock_classes + nr_lock_classes++; | |
798 | debug_atomic_inc(&nr_unused_locks); | |
799 | class->key = key; | |
800 | class->name = lock->name; | |
801 | class->subclass = subclass; | |
802 | INIT_LIST_HEAD(&class->lock_entry); | |
803 | INIT_LIST_HEAD(&class->locks_before); | |
804 | INIT_LIST_HEAD(&class->locks_after); | |
805 | class->name_version = count_matching_names(class); | |
806 | /* | |
807 | * We use RCU's safe list-add method to make | |
808 | * parallel walking of the hash-list safe: | |
809 | */ | |
810 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
811 | /* |
812 | * Add it to the global list of classes: | |
813 | */ | |
814 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
815 | |
816 | if (verbose(class)) { | |
817 | graph_unlock(); | |
818 | raw_local_irq_restore(flags); | |
819 | ||
820 | printk("\nnew class %p: %s", class->key, class->name); | |
821 | if (class->name_version > 1) | |
822 | printk("#%d", class->name_version); | |
823 | printk("\n"); | |
824 | dump_stack(); | |
825 | ||
826 | raw_local_irq_save(flags); | |
827 | if (!graph_lock()) { | |
828 | raw_local_irq_restore(flags); | |
829 | return NULL; | |
830 | } | |
831 | } | |
832 | out_unlock_set: | |
833 | graph_unlock(); | |
834 | raw_local_irq_restore(flags); | |
835 | ||
836 | if (!subclass || force) | |
837 | lock->class_cache = class; | |
838 | ||
839 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
840 | return NULL; | |
841 | ||
842 | return class; | |
843 | } | |
844 | ||
845 | #ifdef CONFIG_PROVE_LOCKING | |
846 | /* | |
847 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
848 | * with NULL on failure) | |
849 | */ | |
850 | static struct lock_list *alloc_list_entry(void) | |
851 | { | |
852 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
853 | if (!debug_locks_off_graph_unlock()) | |
854 | return NULL; | |
855 | ||
856 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
857 | printk("turning off the locking correctness validator.\n"); | |
858 | return NULL; | |
859 | } | |
860 | return list_entries + nr_list_entries++; | |
861 | } | |
862 | ||
863 | /* | |
864 | * Add a new dependency to the head of the list: | |
865 | */ | |
866 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
867 | struct list_head *head, unsigned long ip, int distance) | |
868 | { | |
869 | struct lock_list *entry; | |
870 | /* | |
871 | * Lock not present yet - get a new dependency struct and | |
872 | * add it to the list: | |
873 | */ | |
874 | entry = alloc_list_entry(); | |
875 | if (!entry) | |
876 | return 0; | |
877 | ||
8e18257d PZ |
878 | if (!save_trace(&entry->trace)) |
879 | return 0; | |
880 | ||
74870172 ZY |
881 | entry->class = this; |
882 | entry->distance = distance; | |
8e18257d PZ |
883 | /* |
884 | * Since we never remove from the dependency list, the list can | |
885 | * be walked lockless by other CPUs, it's only allocation | |
886 | * that must be protected by the spinlock. But this also means | |
887 | * we must make new entries visible only once writes to the | |
888 | * entry become visible - hence the RCU op: | |
889 | */ | |
890 | list_add_tail_rcu(&entry->entry, head); | |
891 | ||
892 | return 1; | |
893 | } | |
894 | ||
895 | /* | |
896 | * Recursive, forwards-direction lock-dependency checking, used for | |
897 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
898 | * checking. | |
899 | * | |
900 | * (to keep the stackframe of the recursive functions small we | |
901 | * use these global variables, and we also mark various helper | |
902 | * functions as noinline.) | |
903 | */ | |
904 | static struct held_lock *check_source, *check_target; | |
905 | ||
906 | /* | |
907 | * Print a dependency chain entry (this is only done when a deadlock | |
908 | * has been detected): | |
909 | */ | |
910 | static noinline int | |
911 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |
912 | { | |
913 | if (debug_locks_silent) | |
914 | return 0; | |
915 | printk("\n-> #%u", depth); | |
916 | print_lock_name(target->class); | |
917 | printk(":\n"); | |
918 | print_stack_trace(&target->trace, 6); | |
919 | ||
920 | return 0; | |
921 | } | |
922 | ||
923 | /* | |
924 | * When a circular dependency is detected, print the | |
925 | * header first: | |
926 | */ | |
927 | static noinline int | |
928 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) | |
929 | { | |
930 | struct task_struct *curr = current; | |
931 | ||
932 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
933 | return 0; | |
934 | ||
935 | printk("\n=======================================================\n"); | |
936 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
937 | print_kernel_version(); | |
938 | printk( "-------------------------------------------------------\n"); | |
939 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 940 | curr->comm, task_pid_nr(curr)); |
8e18257d PZ |
941 | print_lock(check_source); |
942 | printk("\nbut task is already holding lock:\n"); | |
943 | print_lock(check_target); | |
944 | printk("\nwhich lock already depends on the new lock.\n\n"); | |
945 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
946 | ||
947 | print_circular_bug_entry(entry, depth); | |
948 | ||
949 | return 0; | |
950 | } | |
951 | ||
952 | static noinline int print_circular_bug_tail(void) | |
953 | { | |
954 | struct task_struct *curr = current; | |
955 | struct lock_list this; | |
956 | ||
957 | if (debug_locks_silent) | |
958 | return 0; | |
959 | ||
f82b217e | 960 | this.class = hlock_class(check_source); |
8e18257d PZ |
961 | if (!save_trace(&this.trace)) |
962 | return 0; | |
963 | ||
964 | print_circular_bug_entry(&this, 0); | |
965 | ||
966 | printk("\nother info that might help us debug this:\n\n"); | |
967 | lockdep_print_held_locks(curr); | |
968 | ||
969 | printk("\nstack backtrace:\n"); | |
970 | dump_stack(); | |
971 | ||
972 | return 0; | |
973 | } | |
974 | ||
975 | #define RECURSION_LIMIT 40 | |
976 | ||
977 | static int noinline print_infinite_recursion_bug(void) | |
978 | { | |
979 | if (!debug_locks_off_graph_unlock()) | |
980 | return 0; | |
981 | ||
982 | WARN_ON(1); | |
983 | ||
984 | return 0; | |
985 | } | |
986 | ||
419ca3f1 DM |
987 | unsigned long __lockdep_count_forward_deps(struct lock_class *class, |
988 | unsigned int depth) | |
989 | { | |
990 | struct lock_list *entry; | |
991 | unsigned long ret = 1; | |
992 | ||
993 | if (lockdep_dependency_visit(class, depth)) | |
994 | return 0; | |
995 | ||
996 | /* | |
997 | * Recurse this class's dependency list: | |
998 | */ | |
999 | list_for_each_entry(entry, &class->locks_after, entry) | |
1000 | ret += __lockdep_count_forward_deps(entry->class, depth + 1); | |
1001 | ||
1002 | return ret; | |
1003 | } | |
1004 | ||
1005 | unsigned long lockdep_count_forward_deps(struct lock_class *class) | |
1006 | { | |
1007 | unsigned long ret, flags; | |
1008 | ||
1009 | local_irq_save(flags); | |
1010 | __raw_spin_lock(&lockdep_lock); | |
1011 | ret = __lockdep_count_forward_deps(class, 0); | |
1012 | __raw_spin_unlock(&lockdep_lock); | |
1013 | local_irq_restore(flags); | |
1014 | ||
1015 | return ret; | |
1016 | } | |
1017 | ||
1018 | unsigned long __lockdep_count_backward_deps(struct lock_class *class, | |
1019 | unsigned int depth) | |
1020 | { | |
1021 | struct lock_list *entry; | |
1022 | unsigned long ret = 1; | |
1023 | ||
1024 | if (lockdep_dependency_visit(class, depth)) | |
1025 | return 0; | |
1026 | /* | |
1027 | * Recurse this class's dependency list: | |
1028 | */ | |
1029 | list_for_each_entry(entry, &class->locks_before, entry) | |
1030 | ret += __lockdep_count_backward_deps(entry->class, depth + 1); | |
1031 | ||
1032 | return ret; | |
1033 | } | |
1034 | ||
1035 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1036 | { | |
1037 | unsigned long ret, flags; | |
1038 | ||
1039 | local_irq_save(flags); | |
1040 | __raw_spin_lock(&lockdep_lock); | |
1041 | ret = __lockdep_count_backward_deps(class, 0); | |
1042 | __raw_spin_unlock(&lockdep_lock); | |
1043 | local_irq_restore(flags); | |
1044 | ||
1045 | return ret; | |
1046 | } | |
1047 | ||
8e18257d PZ |
1048 | /* |
1049 | * Prove that the dependency graph starting at <entry> can not | |
1050 | * lead to <target>. Print an error and return 0 if it does. | |
1051 | */ | |
1052 | static noinline int | |
1053 | check_noncircular(struct lock_class *source, unsigned int depth) | |
1054 | { | |
1055 | struct lock_list *entry; | |
1056 | ||
419ca3f1 DM |
1057 | if (lockdep_dependency_visit(source, depth)) |
1058 | return 1; | |
1059 | ||
8e18257d PZ |
1060 | debug_atomic_inc(&nr_cyclic_check_recursions); |
1061 | if (depth > max_recursion_depth) | |
fbb9ce95 | 1062 | max_recursion_depth = depth; |
ca268c69 | 1063 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1064 | return print_infinite_recursion_bug(); |
1065 | /* | |
1066 | * Check this lock's dependency list: | |
1067 | */ | |
1068 | list_for_each_entry(entry, &source->locks_after, entry) { | |
f82b217e | 1069 | if (entry->class == hlock_class(check_target)) |
fbb9ce95 IM |
1070 | return print_circular_bug_header(entry, depth+1); |
1071 | debug_atomic_inc(&nr_cyclic_checks); | |
1072 | if (!check_noncircular(entry->class, depth+1)) | |
1073 | return print_circular_bug_entry(entry, depth+1); | |
1074 | } | |
1075 | return 1; | |
1076 | } | |
1077 | ||
81d68a96 | 1078 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1079 | /* |
1080 | * Forwards and backwards subgraph searching, for the purposes of | |
1081 | * proving that two subgraphs can be connected by a new dependency | |
1082 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1083 | */ | |
1084 | static enum lock_usage_bit find_usage_bit; | |
1085 | static struct lock_class *forwards_match, *backwards_match; | |
1086 | ||
1087 | /* | |
1088 | * Find a node in the forwards-direction dependency sub-graph starting | |
1089 | * at <source> that matches <find_usage_bit>. | |
1090 | * | |
1091 | * Return 2 if such a node exists in the subgraph, and put that node | |
1092 | * into <forwards_match>. | |
1093 | * | |
1094 | * Return 1 otherwise and keep <forwards_match> unchanged. | |
1095 | * Return 0 on error. | |
1096 | */ | |
1097 | static noinline int | |
1098 | find_usage_forwards(struct lock_class *source, unsigned int depth) | |
1099 | { | |
1100 | struct lock_list *entry; | |
1101 | int ret; | |
1102 | ||
419ca3f1 DM |
1103 | if (lockdep_dependency_visit(source, depth)) |
1104 | return 1; | |
1105 | ||
fbb9ce95 IM |
1106 | if (depth > max_recursion_depth) |
1107 | max_recursion_depth = depth; | |
ca268c69 | 1108 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1109 | return print_infinite_recursion_bug(); |
1110 | ||
1111 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
1112 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1113 | forwards_match = source; | |
1114 | return 2; | |
1115 | } | |
1116 | ||
1117 | /* | |
1118 | * Check this lock's dependency list: | |
1119 | */ | |
1120 | list_for_each_entry(entry, &source->locks_after, entry) { | |
1121 | debug_atomic_inc(&nr_find_usage_forwards_recursions); | |
1122 | ret = find_usage_forwards(entry->class, depth+1); | |
1123 | if (ret == 2 || ret == 0) | |
1124 | return ret; | |
1125 | } | |
1126 | return 1; | |
1127 | } | |
1128 | ||
1129 | /* | |
1130 | * Find a node in the backwards-direction dependency sub-graph starting | |
1131 | * at <source> that matches <find_usage_bit>. | |
1132 | * | |
1133 | * Return 2 if such a node exists in the subgraph, and put that node | |
1134 | * into <backwards_match>. | |
1135 | * | |
1136 | * Return 1 otherwise and keep <backwards_match> unchanged. | |
1137 | * Return 0 on error. | |
1138 | */ | |
1d09daa5 | 1139 | static noinline int |
fbb9ce95 IM |
1140 | find_usage_backwards(struct lock_class *source, unsigned int depth) |
1141 | { | |
1142 | struct lock_list *entry; | |
1143 | int ret; | |
1144 | ||
419ca3f1 DM |
1145 | if (lockdep_dependency_visit(source, depth)) |
1146 | return 1; | |
1147 | ||
381a2292 JP |
1148 | if (!__raw_spin_is_locked(&lockdep_lock)) |
1149 | return DEBUG_LOCKS_WARN_ON(1); | |
1150 | ||
fbb9ce95 IM |
1151 | if (depth > max_recursion_depth) |
1152 | max_recursion_depth = depth; | |
ca268c69 | 1153 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1154 | return print_infinite_recursion_bug(); |
1155 | ||
1156 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
1157 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1158 | backwards_match = source; | |
1159 | return 2; | |
1160 | } | |
1161 | ||
f82b217e DJ |
1162 | if (!source && debug_locks_off_graph_unlock()) { |
1163 | WARN_ON(1); | |
1164 | return 0; | |
1165 | } | |
1166 | ||
fbb9ce95 IM |
1167 | /* |
1168 | * Check this lock's dependency list: | |
1169 | */ | |
1170 | list_for_each_entry(entry, &source->locks_before, entry) { | |
1171 | debug_atomic_inc(&nr_find_usage_backwards_recursions); | |
1172 | ret = find_usage_backwards(entry->class, depth+1); | |
1173 | if (ret == 2 || ret == 0) | |
1174 | return ret; | |
1175 | } | |
1176 | return 1; | |
1177 | } | |
1178 | ||
1179 | static int | |
1180 | print_bad_irq_dependency(struct task_struct *curr, | |
1181 | struct held_lock *prev, | |
1182 | struct held_lock *next, | |
1183 | enum lock_usage_bit bit1, | |
1184 | enum lock_usage_bit bit2, | |
1185 | const char *irqclass) | |
1186 | { | |
74c383f1 | 1187 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1188 | return 0; |
1189 | ||
1190 | printk("\n======================================================\n"); | |
1191 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1192 | irqclass, irqclass); | |
99de055a | 1193 | print_kernel_version(); |
fbb9ce95 IM |
1194 | printk( "------------------------------------------------------\n"); |
1195 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1196 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1197 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1198 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1199 | curr->hardirqs_enabled, | |
1200 | curr->softirqs_enabled); | |
1201 | print_lock(next); | |
1202 | ||
1203 | printk("\nand this task is already holding:\n"); | |
1204 | print_lock(prev); | |
1205 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1206 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1207 | printk(" ->"); |
f82b217e | 1208 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1209 | printk("\n"); |
1210 | ||
1211 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1212 | irqclass); | |
1213 | print_lock_name(backwards_match); | |
1214 | printk("\n... which became %s-irq-safe at:\n", irqclass); | |
1215 | ||
1216 | print_stack_trace(backwards_match->usage_traces + bit1, 1); | |
1217 | ||
1218 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
1219 | print_lock_name(forwards_match); | |
1220 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); | |
1221 | printk("..."); | |
1222 | ||
1223 | print_stack_trace(forwards_match->usage_traces + bit2, 1); | |
1224 | ||
1225 | printk("\nother info that might help us debug this:\n\n"); | |
1226 | lockdep_print_held_locks(curr); | |
1227 | ||
1228 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); | |
1229 | print_lock_dependencies(backwards_match, 0); | |
1230 | ||
1231 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); | |
1232 | print_lock_dependencies(forwards_match, 0); | |
1233 | ||
1234 | printk("\nstack backtrace:\n"); | |
1235 | dump_stack(); | |
1236 | ||
1237 | return 0; | |
1238 | } | |
1239 | ||
1240 | static int | |
1241 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1242 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1243 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1244 | { | |
1245 | int ret; | |
1246 | ||
1247 | find_usage_bit = bit_backwards; | |
1248 | /* fills in <backwards_match> */ | |
f82b217e | 1249 | ret = find_usage_backwards(hlock_class(prev), 0); |
fbb9ce95 IM |
1250 | if (!ret || ret == 1) |
1251 | return ret; | |
1252 | ||
1253 | find_usage_bit = bit_forwards; | |
f82b217e | 1254 | ret = find_usage_forwards(hlock_class(next), 0); |
fbb9ce95 IM |
1255 | if (!ret || ret == 1) |
1256 | return ret; | |
1257 | /* ret == 2 */ | |
1258 | return print_bad_irq_dependency(curr, prev, next, | |
1259 | bit_backwards, bit_forwards, irqclass); | |
1260 | } | |
1261 | ||
8e18257d PZ |
1262 | static int |
1263 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1264 | struct held_lock *next) | |
1265 | { | |
1266 | /* | |
1267 | * Prove that the new dependency does not connect a hardirq-safe | |
1268 | * lock with a hardirq-unsafe lock - to achieve this we search | |
1269 | * the backwards-subgraph starting at <prev>, and the | |
1270 | * forwards-subgraph starting at <next>: | |
1271 | */ | |
1272 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, | |
1273 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1274 | return 0; | |
1275 | ||
1276 | /* | |
1277 | * Prove that the new dependency does not connect a hardirq-safe-read | |
1278 | * lock with a hardirq-unsafe lock - to achieve this we search | |
1279 | * the backwards-subgraph starting at <prev>, and the | |
1280 | * forwards-subgraph starting at <next>: | |
1281 | */ | |
1282 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, | |
1283 | LOCK_ENABLED_HARDIRQS, "hard-read")) | |
1284 | return 0; | |
1285 | ||
1286 | /* | |
1287 | * Prove that the new dependency does not connect a softirq-safe | |
1288 | * lock with a softirq-unsafe lock - to achieve this we search | |
1289 | * the backwards-subgraph starting at <prev>, and the | |
1290 | * forwards-subgraph starting at <next>: | |
1291 | */ | |
1292 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, | |
1293 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1294 | return 0; | |
1295 | /* | |
1296 | * Prove that the new dependency does not connect a softirq-safe-read | |
1297 | * lock with a softirq-unsafe lock - to achieve this we search | |
1298 | * the backwards-subgraph starting at <prev>, and the | |
1299 | * forwards-subgraph starting at <next>: | |
1300 | */ | |
1301 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, | |
1302 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1303 | return 0; | |
1304 | ||
1305 | return 1; | |
1306 | } | |
1307 | ||
1308 | static void inc_chains(void) | |
1309 | { | |
1310 | if (current->hardirq_context) | |
1311 | nr_hardirq_chains++; | |
1312 | else { | |
1313 | if (current->softirq_context) | |
1314 | nr_softirq_chains++; | |
1315 | else | |
1316 | nr_process_chains++; | |
1317 | } | |
1318 | } | |
1319 | ||
1320 | #else | |
1321 | ||
1322 | static inline int | |
1323 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1324 | struct held_lock *next) | |
1325 | { | |
1326 | return 1; | |
1327 | } | |
1328 | ||
1329 | static inline void inc_chains(void) | |
1330 | { | |
1331 | nr_process_chains++; | |
1332 | } | |
1333 | ||
fbb9ce95 IM |
1334 | #endif |
1335 | ||
1336 | static int | |
1337 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1338 | struct held_lock *next) | |
1339 | { | |
74c383f1 | 1340 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1341 | return 0; |
1342 | ||
1343 | printk("\n=============================================\n"); | |
1344 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1345 | print_kernel_version(); |
fbb9ce95 IM |
1346 | printk( "---------------------------------------------\n"); |
1347 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1348 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1349 | print_lock(next); |
1350 | printk("\nbut task is already holding lock:\n"); | |
1351 | print_lock(prev); | |
1352 | ||
1353 | printk("\nother info that might help us debug this:\n"); | |
1354 | lockdep_print_held_locks(curr); | |
1355 | ||
1356 | printk("\nstack backtrace:\n"); | |
1357 | dump_stack(); | |
1358 | ||
1359 | return 0; | |
1360 | } | |
1361 | ||
1362 | /* | |
1363 | * Check whether we are holding such a class already. | |
1364 | * | |
1365 | * (Note that this has to be done separately, because the graph cannot | |
1366 | * detect such classes of deadlocks.) | |
1367 | * | |
1368 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1369 | */ | |
1370 | static int | |
1371 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1372 | struct lockdep_map *next_instance, int read) | |
1373 | { | |
1374 | struct held_lock *prev; | |
7531e2f3 | 1375 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1376 | int i; |
1377 | ||
1378 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1379 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1380 | |
1381 | if (prev->instance == next->nest_lock) | |
1382 | nest = prev; | |
1383 | ||
f82b217e | 1384 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1385 | continue; |
7531e2f3 | 1386 | |
fbb9ce95 IM |
1387 | /* |
1388 | * Allow read-after-read recursion of the same | |
6c9076ec | 1389 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1390 | */ |
6c9076ec | 1391 | if ((read == 2) && prev->read) |
fbb9ce95 | 1392 | return 2; |
7531e2f3 PZ |
1393 | |
1394 | /* | |
1395 | * We're holding the nest_lock, which serializes this lock's | |
1396 | * nesting behaviour. | |
1397 | */ | |
1398 | if (nest) | |
1399 | return 2; | |
1400 | ||
fbb9ce95 IM |
1401 | return print_deadlock_bug(curr, prev, next); |
1402 | } | |
1403 | return 1; | |
1404 | } | |
1405 | ||
1406 | /* | |
1407 | * There was a chain-cache miss, and we are about to add a new dependency | |
1408 | * to a previous lock. We recursively validate the following rules: | |
1409 | * | |
1410 | * - would the adding of the <prev> -> <next> dependency create a | |
1411 | * circular dependency in the graph? [== circular deadlock] | |
1412 | * | |
1413 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1414 | * (in the full backwards-subgraph starting at <prev>) with any | |
1415 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1416 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1417 | * | |
1418 | * - does the new prev->next dependency connect any softirq-safe lock | |
1419 | * (in the full backwards-subgraph starting at <prev>) with any | |
1420 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1421 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1422 | * | |
1423 | * any of these scenarios could lead to a deadlock. | |
1424 | * | |
1425 | * Then if all the validations pass, we add the forwards and backwards | |
1426 | * dependency. | |
1427 | */ | |
1428 | static int | |
1429 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1430 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1431 | { |
1432 | struct lock_list *entry; | |
1433 | int ret; | |
1434 | ||
1435 | /* | |
1436 | * Prove that the new <prev> -> <next> dependency would not | |
1437 | * create a circular dependency in the graph. (We do this by | |
1438 | * forward-recursing into the graph starting at <next>, and | |
1439 | * checking whether we can reach <prev>.) | |
1440 | * | |
1441 | * We are using global variables to control the recursion, to | |
1442 | * keep the stackframe size of the recursive functions low: | |
1443 | */ | |
1444 | check_source = next; | |
1445 | check_target = prev; | |
f82b217e | 1446 | if (!(check_noncircular(hlock_class(next), 0))) |
fbb9ce95 IM |
1447 | return print_circular_bug_tail(); |
1448 | ||
8e18257d | 1449 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1450 | return 0; |
1451 | ||
fbb9ce95 IM |
1452 | /* |
1453 | * For recursive read-locks we do all the dependency checks, | |
1454 | * but we dont store read-triggered dependencies (only | |
1455 | * write-triggered dependencies). This ensures that only the | |
1456 | * write-side dependencies matter, and that if for example a | |
1457 | * write-lock never takes any other locks, then the reads are | |
1458 | * equivalent to a NOP. | |
1459 | */ | |
1460 | if (next->read == 2 || prev->read == 2) | |
1461 | return 1; | |
1462 | /* | |
1463 | * Is the <prev> -> <next> dependency already present? | |
1464 | * | |
1465 | * (this may occur even though this is a new chain: consider | |
1466 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1467 | * chains - the second one will be new, but L1 already has | |
1468 | * L2 added to its dependency list, due to the first chain.) | |
1469 | */ | |
f82b217e DJ |
1470 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1471 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1472 | if (distance == 1) |
1473 | entry->distance = 1; | |
fbb9ce95 | 1474 | return 2; |
068135e6 | 1475 | } |
fbb9ce95 IM |
1476 | } |
1477 | ||
1478 | /* | |
1479 | * Ok, all validations passed, add the new lock | |
1480 | * to the previous lock's dependency list: | |
1481 | */ | |
f82b217e DJ |
1482 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1483 | &hlock_class(prev)->locks_after, | |
1484 | next->acquire_ip, distance); | |
068135e6 | 1485 | |
fbb9ce95 IM |
1486 | if (!ret) |
1487 | return 0; | |
910b1b2e | 1488 | |
f82b217e DJ |
1489 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1490 | &hlock_class(next)->locks_before, | |
1491 | next->acquire_ip, distance); | |
910b1b2e JP |
1492 | if (!ret) |
1493 | return 0; | |
fbb9ce95 IM |
1494 | |
1495 | /* | |
8e18257d PZ |
1496 | * Debugging printouts: |
1497 | */ | |
f82b217e | 1498 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1499 | graph_unlock(); |
1500 | printk("\n new dependency: "); | |
f82b217e | 1501 | print_lock_name(hlock_class(prev)); |
8e18257d | 1502 | printk(" => "); |
f82b217e | 1503 | print_lock_name(hlock_class(next)); |
8e18257d | 1504 | printk("\n"); |
fbb9ce95 | 1505 | dump_stack(); |
8e18257d | 1506 | return graph_lock(); |
fbb9ce95 | 1507 | } |
8e18257d PZ |
1508 | return 1; |
1509 | } | |
fbb9ce95 | 1510 | |
8e18257d PZ |
1511 | /* |
1512 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1513 | * The ones that are relevant are (in increasing distance from curr): | |
1514 | * all consecutive trylock entries and the final non-trylock entry - or | |
1515 | * the end of this context's lock-chain - whichever comes first. | |
1516 | */ | |
1517 | static int | |
1518 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1519 | { | |
1520 | int depth = curr->lockdep_depth; | |
1521 | struct held_lock *hlock; | |
d6d897ce | 1522 | |
fbb9ce95 | 1523 | /* |
8e18257d PZ |
1524 | * Debugging checks. |
1525 | * | |
1526 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1527 | */ |
8e18257d PZ |
1528 | if (!depth) |
1529 | goto out_bug; | |
fbb9ce95 | 1530 | /* |
8e18257d PZ |
1531 | * At least two relevant locks must exist for this |
1532 | * to be a head: | |
fbb9ce95 | 1533 | */ |
8e18257d PZ |
1534 | if (curr->held_locks[depth].irq_context != |
1535 | curr->held_locks[depth-1].irq_context) | |
1536 | goto out_bug; | |
74c383f1 | 1537 | |
8e18257d PZ |
1538 | for (;;) { |
1539 | int distance = curr->lockdep_depth - depth + 1; | |
1540 | hlock = curr->held_locks + depth-1; | |
1541 | /* | |
1542 | * Only non-recursive-read entries get new dependencies | |
1543 | * added: | |
1544 | */ | |
1545 | if (hlock->read != 2) { | |
1546 | if (!check_prev_add(curr, hlock, next, distance)) | |
1547 | return 0; | |
1548 | /* | |
1549 | * Stop after the first non-trylock entry, | |
1550 | * as non-trylock entries have added their | |
1551 | * own direct dependencies already, so this | |
1552 | * lock is connected to them indirectly: | |
1553 | */ | |
1554 | if (!hlock->trylock) | |
1555 | break; | |
74c383f1 | 1556 | } |
8e18257d PZ |
1557 | depth--; |
1558 | /* | |
1559 | * End of lock-stack? | |
1560 | */ | |
1561 | if (!depth) | |
1562 | break; | |
1563 | /* | |
1564 | * Stop the search if we cross into another context: | |
1565 | */ | |
1566 | if (curr->held_locks[depth].irq_context != | |
1567 | curr->held_locks[depth-1].irq_context) | |
1568 | break; | |
fbb9ce95 | 1569 | } |
8e18257d PZ |
1570 | return 1; |
1571 | out_bug: | |
1572 | if (!debug_locks_off_graph_unlock()) | |
1573 | return 0; | |
fbb9ce95 | 1574 | |
8e18257d | 1575 | WARN_ON(1); |
fbb9ce95 | 1576 | |
8e18257d | 1577 | return 0; |
fbb9ce95 IM |
1578 | } |
1579 | ||
8e18257d | 1580 | unsigned long nr_lock_chains; |
443cd507 | 1581 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1582 | int nr_chain_hlocks; |
443cd507 HY |
1583 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1584 | ||
1585 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1586 | { | |
1587 | return lock_classes + chain_hlocks[chain->base + i]; | |
1588 | } | |
8e18257d | 1589 | |
fbb9ce95 IM |
1590 | /* |
1591 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1592 | * add it and return 1 - in this case the new dependency chain is |
1593 | * validated. If the key is already hashed, return 0. | |
1594 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1595 | */ |
443cd507 HY |
1596 | static inline int lookup_chain_cache(struct task_struct *curr, |
1597 | struct held_lock *hlock, | |
1598 | u64 chain_key) | |
fbb9ce95 | 1599 | { |
f82b217e | 1600 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1601 | struct list_head *hash_head = chainhashentry(chain_key); |
1602 | struct lock_chain *chain; | |
443cd507 | 1603 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1604 | int i, j, n, cn; |
fbb9ce95 | 1605 | |
381a2292 JP |
1606 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1607 | return 0; | |
fbb9ce95 IM |
1608 | /* |
1609 | * We can walk it lock-free, because entries only get added | |
1610 | * to the hash: | |
1611 | */ | |
1612 | list_for_each_entry(chain, hash_head, entry) { | |
1613 | if (chain->chain_key == chain_key) { | |
1614 | cache_hit: | |
1615 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1616 | if (very_verbose(class)) |
755cd900 AM |
1617 | printk("\nhash chain already cached, key: " |
1618 | "%016Lx tail class: [%p] %s\n", | |
1619 | (unsigned long long)chain_key, | |
1620 | class->key, class->name); | |
fbb9ce95 IM |
1621 | return 0; |
1622 | } | |
1623 | } | |
81fc685a | 1624 | if (very_verbose(class)) |
755cd900 AM |
1625 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1626 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1627 | /* |
1628 | * Allocate a new chain entry from the static array, and add | |
1629 | * it to the hash: | |
1630 | */ | |
74c383f1 IM |
1631 | if (!graph_lock()) |
1632 | return 0; | |
fbb9ce95 IM |
1633 | /* |
1634 | * We have to walk the chain again locked - to avoid duplicates: | |
1635 | */ | |
1636 | list_for_each_entry(chain, hash_head, entry) { | |
1637 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1638 | graph_unlock(); |
fbb9ce95 IM |
1639 | goto cache_hit; |
1640 | } | |
1641 | } | |
1642 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1643 | if (!debug_locks_off_graph_unlock()) |
1644 | return 0; | |
1645 | ||
fbb9ce95 IM |
1646 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1647 | printk("turning off the locking correctness validator.\n"); | |
1648 | return 0; | |
1649 | } | |
1650 | chain = lock_chains + nr_lock_chains++; | |
1651 | chain->chain_key = chain_key; | |
443cd507 HY |
1652 | chain->irq_context = hlock->irq_context; |
1653 | /* Find the first held_lock of current chain */ | |
1654 | hlock_next = hlock; | |
1655 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1656 | hlock_curr = curr->held_locks + i; | |
1657 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1658 | break; | |
1659 | hlock_next = hlock; | |
1660 | } | |
1661 | i++; | |
1662 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1663 | cn = nr_chain_hlocks; |
1664 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1665 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1666 | if (n == cn) | |
1667 | break; | |
1668 | cn = n; | |
1669 | } | |
1670 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1671 | chain->base = cn; | |
443cd507 | 1672 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1673 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1674 | chain_hlocks[chain->base + j] = lock_id; |
1675 | } | |
1676 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1677 | } | |
fbb9ce95 IM |
1678 | list_add_tail_rcu(&chain->entry, hash_head); |
1679 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1680 | inc_chains(); |
1681 | ||
1682 | return 1; | |
1683 | } | |
1684 | ||
1685 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1686 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1687 | { |
1688 | /* | |
1689 | * Trylock needs to maintain the stack of held locks, but it | |
1690 | * does not add new dependencies, because trylock can be done | |
1691 | * in any order. | |
1692 | * | |
1693 | * We look up the chain_key and do the O(N^2) check and update of | |
1694 | * the dependencies only if this is a new dependency chain. | |
1695 | * (If lookup_chain_cache() returns with 1 it acquires | |
1696 | * graph_lock for us) | |
1697 | */ | |
1698 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1699 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1700 | /* |
1701 | * Check whether last held lock: | |
1702 | * | |
1703 | * - is irq-safe, if this lock is irq-unsafe | |
1704 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1705 | * | |
1706 | * And check whether the new lock's dependency graph | |
1707 | * could lead back to the previous lock. | |
1708 | * | |
1709 | * any of these scenarios could lead to a deadlock. If | |
1710 | * All validations | |
1711 | */ | |
1712 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1713 | ||
1714 | if (!ret) | |
1715 | return 0; | |
1716 | /* | |
1717 | * Mark recursive read, as we jump over it when | |
1718 | * building dependencies (just like we jump over | |
1719 | * trylock entries): | |
1720 | */ | |
1721 | if (ret == 2) | |
1722 | hlock->read = 2; | |
1723 | /* | |
1724 | * Add dependency only if this lock is not the head | |
1725 | * of the chain, and if it's not a secondary read-lock: | |
1726 | */ | |
1727 | if (!chain_head && ret != 2) | |
1728 | if (!check_prevs_add(curr, hlock)) | |
1729 | return 0; | |
1730 | graph_unlock(); | |
1731 | } else | |
1732 | /* after lookup_chain_cache(): */ | |
1733 | if (unlikely(!debug_locks)) | |
1734 | return 0; | |
fbb9ce95 IM |
1735 | |
1736 | return 1; | |
1737 | } | |
8e18257d PZ |
1738 | #else |
1739 | static inline int validate_chain(struct task_struct *curr, | |
1740 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1741 | int chain_head, u64 chain_key) |
8e18257d PZ |
1742 | { |
1743 | return 1; | |
1744 | } | |
ca58abcb | 1745 | #endif |
fbb9ce95 IM |
1746 | |
1747 | /* | |
1748 | * We are building curr_chain_key incrementally, so double-check | |
1749 | * it from scratch, to make sure that it's done correctly: | |
1750 | */ | |
1d09daa5 | 1751 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1752 | { |
1753 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1754 | struct held_lock *hlock, *prev_hlock = NULL; | |
1755 | unsigned int i, id; | |
1756 | u64 chain_key = 0; | |
1757 | ||
1758 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1759 | hlock = curr->held_locks + i; | |
1760 | if (chain_key != hlock->prev_chain_key) { | |
1761 | debug_locks_off(); | |
2df8b1d6 | 1762 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1763 | curr->lockdep_depth, i, |
1764 | (unsigned long long)chain_key, | |
1765 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1766 | return; |
1767 | } | |
f82b217e | 1768 | id = hlock->class_idx - 1; |
381a2292 JP |
1769 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1770 | return; | |
1771 | ||
fbb9ce95 IM |
1772 | if (prev_hlock && (prev_hlock->irq_context != |
1773 | hlock->irq_context)) | |
1774 | chain_key = 0; | |
1775 | chain_key = iterate_chain_key(chain_key, id); | |
1776 | prev_hlock = hlock; | |
1777 | } | |
1778 | if (chain_key != curr->curr_chain_key) { | |
1779 | debug_locks_off(); | |
2df8b1d6 | 1780 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1781 | curr->lockdep_depth, i, |
1782 | (unsigned long long)chain_key, | |
1783 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1784 | } |
1785 | #endif | |
1786 | } | |
1787 | ||
8e18257d PZ |
1788 | static int |
1789 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1790 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1791 | { | |
1792 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1793 | return 0; | |
1794 | ||
1795 | printk("\n=================================\n"); | |
1796 | printk( "[ INFO: inconsistent lock state ]\n"); | |
1797 | print_kernel_version(); | |
1798 | printk( "---------------------------------\n"); | |
1799 | ||
1800 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1801 | usage_str[prev_bit], usage_str[new_bit]); | |
1802 | ||
1803 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 1804 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
1805 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
1806 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1807 | trace_hardirqs_enabled(curr), | |
1808 | trace_softirqs_enabled(curr)); | |
1809 | print_lock(this); | |
1810 | ||
1811 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 1812 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
1813 | |
1814 | print_irqtrace_events(curr); | |
1815 | printk("\nother info that might help us debug this:\n"); | |
1816 | lockdep_print_held_locks(curr); | |
1817 | ||
1818 | printk("\nstack backtrace:\n"); | |
1819 | dump_stack(); | |
1820 | ||
1821 | return 0; | |
1822 | } | |
1823 | ||
1824 | /* | |
1825 | * Print out an error if an invalid bit is set: | |
1826 | */ | |
1827 | static inline int | |
1828 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1829 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1830 | { | |
f82b217e | 1831 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
1832 | return print_usage_bug(curr, this, bad_bit, new_bit); |
1833 | return 1; | |
1834 | } | |
1835 | ||
1836 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
1837 | enum lock_usage_bit new_bit); | |
1838 | ||
81d68a96 | 1839 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1840 | |
1841 | /* | |
1842 | * print irq inversion bug: | |
1843 | */ | |
1844 | static int | |
1845 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, | |
1846 | struct held_lock *this, int forwards, | |
1847 | const char *irqclass) | |
1848 | { | |
74c383f1 | 1849 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1850 | return 0; |
1851 | ||
1852 | printk("\n=========================================================\n"); | |
1853 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 1854 | print_kernel_version(); |
fbb9ce95 IM |
1855 | printk( "---------------------------------------------------------\n"); |
1856 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 1857 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1858 | print_lock(this); |
1859 | if (forwards) | |
1860 | printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass); | |
1861 | else | |
1862 | printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass); | |
1863 | print_lock_name(other); | |
1864 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); | |
1865 | ||
1866 | printk("\nother info that might help us debug this:\n"); | |
1867 | lockdep_print_held_locks(curr); | |
1868 | ||
1869 | printk("\nthe first lock's dependencies:\n"); | |
f82b217e | 1870 | print_lock_dependencies(hlock_class(this), 0); |
fbb9ce95 IM |
1871 | |
1872 | printk("\nthe second lock's dependencies:\n"); | |
1873 | print_lock_dependencies(other, 0); | |
1874 | ||
1875 | printk("\nstack backtrace:\n"); | |
1876 | dump_stack(); | |
1877 | ||
1878 | return 0; | |
1879 | } | |
1880 | ||
1881 | /* | |
1882 | * Prove that in the forwards-direction subgraph starting at <this> | |
1883 | * there is no lock matching <mask>: | |
1884 | */ | |
1885 | static int | |
1886 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
1887 | enum lock_usage_bit bit, const char *irqclass) | |
1888 | { | |
1889 | int ret; | |
1890 | ||
1891 | find_usage_bit = bit; | |
1892 | /* fills in <forwards_match> */ | |
f82b217e | 1893 | ret = find_usage_forwards(hlock_class(this), 0); |
fbb9ce95 IM |
1894 | if (!ret || ret == 1) |
1895 | return ret; | |
1896 | ||
1897 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); | |
1898 | } | |
1899 | ||
1900 | /* | |
1901 | * Prove that in the backwards-direction subgraph starting at <this> | |
1902 | * there is no lock matching <mask>: | |
1903 | */ | |
1904 | static int | |
1905 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
1906 | enum lock_usage_bit bit, const char *irqclass) | |
1907 | { | |
1908 | int ret; | |
1909 | ||
1910 | find_usage_bit = bit; | |
1911 | /* fills in <backwards_match> */ | |
f82b217e | 1912 | ret = find_usage_backwards(hlock_class(this), 0); |
fbb9ce95 IM |
1913 | if (!ret || ret == 1) |
1914 | return ret; | |
1915 | ||
1916 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); | |
1917 | } | |
1918 | ||
3117df04 | 1919 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
1920 | { |
1921 | printk("irq event stamp: %u\n", curr->irq_events); | |
1922 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
1923 | print_ip_sym(curr->hardirq_enable_ip); | |
1924 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
1925 | print_ip_sym(curr->hardirq_disable_ip); | |
1926 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
1927 | print_ip_sym(curr->softirq_enable_ip); | |
1928 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
1929 | print_ip_sym(curr->softirq_disable_ip); | |
1930 | } | |
1931 | ||
8e18257d | 1932 | static int hardirq_verbose(struct lock_class *class) |
fbb9ce95 | 1933 | { |
8e18257d PZ |
1934 | #if HARDIRQ_VERBOSE |
1935 | return class_filter(class); | |
1936 | #endif | |
fbb9ce95 IM |
1937 | return 0; |
1938 | } | |
1939 | ||
8e18257d | 1940 | static int softirq_verbose(struct lock_class *class) |
fbb9ce95 | 1941 | { |
8e18257d PZ |
1942 | #if SOFTIRQ_VERBOSE |
1943 | return class_filter(class); | |
1944 | #endif | |
1945 | return 0; | |
fbb9ce95 IM |
1946 | } |
1947 | ||
1948 | #define STRICT_READ_CHECKS 1 | |
1949 | ||
8e18257d PZ |
1950 | static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
1951 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 1952 | { |
8e18257d | 1953 | int ret = 1; |
fbb9ce95 | 1954 | |
8e18257d | 1955 | switch(new_bit) { |
fbb9ce95 IM |
1956 | case LOCK_USED_IN_HARDIRQ: |
1957 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1958 | return 0; | |
1959 | if (!valid_state(curr, this, new_bit, | |
1960 | LOCK_ENABLED_HARDIRQS_READ)) | |
1961 | return 0; | |
1962 | /* | |
1963 | * just marked it hardirq-safe, check that this lock | |
1964 | * took no hardirq-unsafe lock in the past: | |
1965 | */ | |
1966 | if (!check_usage_forwards(curr, this, | |
1967 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1968 | return 0; | |
1969 | #if STRICT_READ_CHECKS | |
1970 | /* | |
1971 | * just marked it hardirq-safe, check that this lock | |
1972 | * took no hardirq-unsafe-read lock in the past: | |
1973 | */ | |
1974 | if (!check_usage_forwards(curr, this, | |
1975 | LOCK_ENABLED_HARDIRQS_READ, "hard-read")) | |
1976 | return 0; | |
1977 | #endif | |
f82b217e | 1978 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
1979 | ret = 2; |
1980 | break; | |
1981 | case LOCK_USED_IN_SOFTIRQ: | |
1982 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1983 | return 0; | |
1984 | if (!valid_state(curr, this, new_bit, | |
1985 | LOCK_ENABLED_SOFTIRQS_READ)) | |
1986 | return 0; | |
1987 | /* | |
1988 | * just marked it softirq-safe, check that this lock | |
1989 | * took no softirq-unsafe lock in the past: | |
1990 | */ | |
1991 | if (!check_usage_forwards(curr, this, | |
1992 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1993 | return 0; | |
1994 | #if STRICT_READ_CHECKS | |
1995 | /* | |
1996 | * just marked it softirq-safe, check that this lock | |
1997 | * took no softirq-unsafe-read lock in the past: | |
1998 | */ | |
1999 | if (!check_usage_forwards(curr, this, | |
2000 | LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) | |
2001 | return 0; | |
2002 | #endif | |
f82b217e | 2003 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2004 | ret = 2; |
2005 | break; | |
2006 | case LOCK_USED_IN_HARDIRQ_READ: | |
2007 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
2008 | return 0; | |
2009 | /* | |
2010 | * just marked it hardirq-read-safe, check that this lock | |
2011 | * took no hardirq-unsafe lock in the past: | |
2012 | */ | |
2013 | if (!check_usage_forwards(curr, this, | |
2014 | LOCK_ENABLED_HARDIRQS, "hard")) | |
2015 | return 0; | |
f82b217e | 2016 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2017 | ret = 2; |
2018 | break; | |
2019 | case LOCK_USED_IN_SOFTIRQ_READ: | |
2020 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
2021 | return 0; | |
2022 | /* | |
2023 | * just marked it softirq-read-safe, check that this lock | |
2024 | * took no softirq-unsafe lock in the past: | |
2025 | */ | |
2026 | if (!check_usage_forwards(curr, this, | |
2027 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
2028 | return 0; | |
f82b217e | 2029 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2030 | ret = 2; |
2031 | break; | |
2032 | case LOCK_ENABLED_HARDIRQS: | |
2033 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
2034 | return 0; | |
2035 | if (!valid_state(curr, this, new_bit, | |
2036 | LOCK_USED_IN_HARDIRQ_READ)) | |
2037 | return 0; | |
2038 | /* | |
2039 | * just marked it hardirq-unsafe, check that no hardirq-safe | |
2040 | * lock in the system ever took it in the past: | |
2041 | */ | |
2042 | if (!check_usage_backwards(curr, this, | |
2043 | LOCK_USED_IN_HARDIRQ, "hard")) | |
2044 | return 0; | |
2045 | #if STRICT_READ_CHECKS | |
2046 | /* | |
2047 | * just marked it hardirq-unsafe, check that no | |
2048 | * hardirq-safe-read lock in the system ever took | |
2049 | * it in the past: | |
2050 | */ | |
2051 | if (!check_usage_backwards(curr, this, | |
2052 | LOCK_USED_IN_HARDIRQ_READ, "hard-read")) | |
2053 | return 0; | |
2054 | #endif | |
f82b217e | 2055 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2056 | ret = 2; |
2057 | break; | |
2058 | case LOCK_ENABLED_SOFTIRQS: | |
2059 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
2060 | return 0; | |
2061 | if (!valid_state(curr, this, new_bit, | |
2062 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2063 | return 0; | |
2064 | /* | |
2065 | * just marked it softirq-unsafe, check that no softirq-safe | |
2066 | * lock in the system ever took it in the past: | |
2067 | */ | |
2068 | if (!check_usage_backwards(curr, this, | |
2069 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
2070 | return 0; | |
2071 | #if STRICT_READ_CHECKS | |
2072 | /* | |
2073 | * just marked it softirq-unsafe, check that no | |
2074 | * softirq-safe-read lock in the system ever took | |
2075 | * it in the past: | |
2076 | */ | |
2077 | if (!check_usage_backwards(curr, this, | |
2078 | LOCK_USED_IN_SOFTIRQ_READ, "soft-read")) | |
2079 | return 0; | |
2080 | #endif | |
f82b217e | 2081 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2082 | ret = 2; |
2083 | break; | |
2084 | case LOCK_ENABLED_HARDIRQS_READ: | |
2085 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
2086 | return 0; | |
2087 | #if STRICT_READ_CHECKS | |
2088 | /* | |
2089 | * just marked it hardirq-read-unsafe, check that no | |
2090 | * hardirq-safe lock in the system ever took it in the past: | |
2091 | */ | |
2092 | if (!check_usage_backwards(curr, this, | |
2093 | LOCK_USED_IN_HARDIRQ, "hard")) | |
2094 | return 0; | |
2095 | #endif | |
f82b217e | 2096 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2097 | ret = 2; |
2098 | break; | |
2099 | case LOCK_ENABLED_SOFTIRQS_READ: | |
2100 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
2101 | return 0; | |
2102 | #if STRICT_READ_CHECKS | |
2103 | /* | |
2104 | * just marked it softirq-read-unsafe, check that no | |
2105 | * softirq-safe lock in the system ever took it in the past: | |
2106 | */ | |
2107 | if (!check_usage_backwards(curr, this, | |
2108 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
2109 | return 0; | |
2110 | #endif | |
f82b217e | 2111 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2112 | ret = 2; |
2113 | break; | |
fbb9ce95 | 2114 | default: |
fbb9ce95 | 2115 | WARN_ON(1); |
8e18257d | 2116 | break; |
fbb9ce95 IM |
2117 | } |
2118 | ||
2119 | return ret; | |
2120 | } | |
2121 | ||
fbb9ce95 IM |
2122 | /* |
2123 | * Mark all held locks with a usage bit: | |
2124 | */ | |
1d09daa5 | 2125 | static int |
4ff773bb | 2126 | mark_held_locks(struct task_struct *curr, int hardirq) |
fbb9ce95 IM |
2127 | { |
2128 | enum lock_usage_bit usage_bit; | |
2129 | struct held_lock *hlock; | |
2130 | int i; | |
2131 | ||
2132 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2133 | hlock = curr->held_locks + i; | |
2134 | ||
2135 | if (hardirq) { | |
2136 | if (hlock->read) | |
2137 | usage_bit = LOCK_ENABLED_HARDIRQS_READ; | |
2138 | else | |
2139 | usage_bit = LOCK_ENABLED_HARDIRQS; | |
2140 | } else { | |
2141 | if (hlock->read) | |
2142 | usage_bit = LOCK_ENABLED_SOFTIRQS_READ; | |
2143 | else | |
2144 | usage_bit = LOCK_ENABLED_SOFTIRQS; | |
2145 | } | |
4ff773bb | 2146 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2147 | return 0; |
2148 | } | |
2149 | ||
2150 | return 1; | |
2151 | } | |
2152 | ||
2153 | /* | |
2154 | * Debugging helper: via this flag we know that we are in | |
2155 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2156 | */ | |
2157 | static int early_boot_irqs_enabled; | |
2158 | ||
2159 | void early_boot_irqs_off(void) | |
2160 | { | |
2161 | early_boot_irqs_enabled = 0; | |
2162 | } | |
2163 | ||
2164 | void early_boot_irqs_on(void) | |
2165 | { | |
2166 | early_boot_irqs_enabled = 1; | |
2167 | } | |
2168 | ||
2169 | /* | |
2170 | * Hardirqs will be enabled: | |
2171 | */ | |
6afe40b4 | 2172 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2173 | { |
2174 | struct task_struct *curr = current; | |
fbb9ce95 | 2175 | |
6afe40b4 | 2176 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2177 | |
fbb9ce95 IM |
2178 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2179 | return; | |
2180 | ||
2181 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2182 | return; | |
2183 | ||
2184 | if (unlikely(curr->hardirqs_enabled)) { | |
2185 | debug_atomic_inc(&redundant_hardirqs_on); | |
2186 | return; | |
2187 | } | |
2188 | /* we'll do an OFF -> ON transition: */ | |
2189 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2190 | |
2191 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2192 | return; | |
2193 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2194 | return; | |
2195 | /* | |
2196 | * We are going to turn hardirqs on, so set the | |
2197 | * usage bit for all held locks: | |
2198 | */ | |
4ff773bb | 2199 | if (!mark_held_locks(curr, 1)) |
fbb9ce95 IM |
2200 | return; |
2201 | /* | |
2202 | * If we have softirqs enabled, then set the usage | |
2203 | * bit for all held locks. (disabled hardirqs prevented | |
2204 | * this bit from being set before) | |
2205 | */ | |
2206 | if (curr->softirqs_enabled) | |
4ff773bb | 2207 | if (!mark_held_locks(curr, 0)) |
fbb9ce95 IM |
2208 | return; |
2209 | ||
8e18257d PZ |
2210 | curr->hardirq_enable_ip = ip; |
2211 | curr->hardirq_enable_event = ++curr->irq_events; | |
2212 | debug_atomic_inc(&hardirqs_on_events); | |
2213 | } | |
81d68a96 | 2214 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2215 | |
1d09daa5 | 2216 | void trace_hardirqs_on(void) |
81d68a96 SR |
2217 | { |
2218 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2219 | } | |
8e18257d PZ |
2220 | EXPORT_SYMBOL(trace_hardirqs_on); |
2221 | ||
2222 | /* | |
2223 | * Hardirqs were disabled: | |
2224 | */ | |
6afe40b4 | 2225 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2226 | { |
2227 | struct task_struct *curr = current; | |
2228 | ||
6afe40b4 | 2229 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2230 | |
8e18257d PZ |
2231 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2232 | return; | |
2233 | ||
2234 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2235 | return; | |
2236 | ||
2237 | if (curr->hardirqs_enabled) { | |
2238 | /* | |
2239 | * We have done an ON -> OFF transition: | |
2240 | */ | |
2241 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2242 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2243 | curr->hardirq_disable_event = ++curr->irq_events; |
2244 | debug_atomic_inc(&hardirqs_off_events); | |
2245 | } else | |
2246 | debug_atomic_inc(&redundant_hardirqs_off); | |
2247 | } | |
81d68a96 | 2248 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2249 | |
1d09daa5 | 2250 | void trace_hardirqs_off(void) |
81d68a96 SR |
2251 | { |
2252 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2253 | } | |
8e18257d PZ |
2254 | EXPORT_SYMBOL(trace_hardirqs_off); |
2255 | ||
2256 | /* | |
2257 | * Softirqs will be enabled: | |
2258 | */ | |
2259 | void trace_softirqs_on(unsigned long ip) | |
2260 | { | |
2261 | struct task_struct *curr = current; | |
2262 | ||
2263 | if (unlikely(!debug_locks)) | |
2264 | return; | |
2265 | ||
2266 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2267 | return; | |
2268 | ||
2269 | if (curr->softirqs_enabled) { | |
2270 | debug_atomic_inc(&redundant_softirqs_on); | |
2271 | return; | |
2272 | } | |
2273 | ||
2274 | /* | |
2275 | * We'll do an OFF -> ON transition: | |
2276 | */ | |
2277 | curr->softirqs_enabled = 1; | |
2278 | curr->softirq_enable_ip = ip; | |
2279 | curr->softirq_enable_event = ++curr->irq_events; | |
2280 | debug_atomic_inc(&softirqs_on_events); | |
2281 | /* | |
2282 | * We are going to turn softirqs on, so set the | |
2283 | * usage bit for all held locks, if hardirqs are | |
2284 | * enabled too: | |
2285 | */ | |
2286 | if (curr->hardirqs_enabled) | |
2287 | mark_held_locks(curr, 0); | |
2288 | } | |
2289 | ||
2290 | /* | |
2291 | * Softirqs were disabled: | |
2292 | */ | |
2293 | void trace_softirqs_off(unsigned long ip) | |
2294 | { | |
2295 | struct task_struct *curr = current; | |
2296 | ||
2297 | if (unlikely(!debug_locks)) | |
2298 | return; | |
2299 | ||
2300 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2301 | return; | |
2302 | ||
2303 | if (curr->softirqs_enabled) { | |
2304 | /* | |
2305 | * We have done an ON -> OFF transition: | |
2306 | */ | |
2307 | curr->softirqs_enabled = 0; | |
2308 | curr->softirq_disable_ip = ip; | |
2309 | curr->softirq_disable_event = ++curr->irq_events; | |
2310 | debug_atomic_inc(&softirqs_off_events); | |
2311 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2312 | } else | |
2313 | debug_atomic_inc(&redundant_softirqs_off); | |
2314 | } | |
2315 | ||
2316 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) | |
2317 | { | |
2318 | /* | |
2319 | * If non-trylock use in a hardirq or softirq context, then | |
2320 | * mark the lock as used in these contexts: | |
2321 | */ | |
2322 | if (!hlock->trylock) { | |
2323 | if (hlock->read) { | |
2324 | if (curr->hardirq_context) | |
2325 | if (!mark_lock(curr, hlock, | |
2326 | LOCK_USED_IN_HARDIRQ_READ)) | |
2327 | return 0; | |
2328 | if (curr->softirq_context) | |
2329 | if (!mark_lock(curr, hlock, | |
2330 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2331 | return 0; | |
2332 | } else { | |
2333 | if (curr->hardirq_context) | |
2334 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2335 | return 0; | |
2336 | if (curr->softirq_context) | |
2337 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2338 | return 0; | |
2339 | } | |
2340 | } | |
2341 | if (!hlock->hardirqs_off) { | |
2342 | if (hlock->read) { | |
2343 | if (!mark_lock(curr, hlock, | |
2344 | LOCK_ENABLED_HARDIRQS_READ)) | |
2345 | return 0; | |
2346 | if (curr->softirqs_enabled) | |
2347 | if (!mark_lock(curr, hlock, | |
2348 | LOCK_ENABLED_SOFTIRQS_READ)) | |
2349 | return 0; | |
2350 | } else { | |
2351 | if (!mark_lock(curr, hlock, | |
2352 | LOCK_ENABLED_HARDIRQS)) | |
2353 | return 0; | |
2354 | if (curr->softirqs_enabled) | |
2355 | if (!mark_lock(curr, hlock, | |
2356 | LOCK_ENABLED_SOFTIRQS)) | |
2357 | return 0; | |
2358 | } | |
2359 | } | |
2360 | ||
2361 | return 1; | |
2362 | } | |
2363 | ||
2364 | static int separate_irq_context(struct task_struct *curr, | |
2365 | struct held_lock *hlock) | |
2366 | { | |
2367 | unsigned int depth = curr->lockdep_depth; | |
2368 | ||
2369 | /* | |
2370 | * Keep track of points where we cross into an interrupt context: | |
2371 | */ | |
2372 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2373 | curr->softirq_context; | |
2374 | if (depth) { | |
2375 | struct held_lock *prev_hlock; | |
2376 | ||
2377 | prev_hlock = curr->held_locks + depth-1; | |
2378 | /* | |
2379 | * If we cross into another context, reset the | |
2380 | * hash key (this also prevents the checking and the | |
2381 | * adding of the dependency to 'prev'): | |
2382 | */ | |
2383 | if (prev_hlock->irq_context != hlock->irq_context) | |
2384 | return 1; | |
2385 | } | |
2386 | return 0; | |
fbb9ce95 IM |
2387 | } |
2388 | ||
8e18257d | 2389 | #else |
fbb9ce95 | 2390 | |
8e18257d PZ |
2391 | static inline |
2392 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2393 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2394 | { |
8e18257d PZ |
2395 | WARN_ON(1); |
2396 | return 1; | |
2397 | } | |
fbb9ce95 | 2398 | |
8e18257d PZ |
2399 | static inline int mark_irqflags(struct task_struct *curr, |
2400 | struct held_lock *hlock) | |
2401 | { | |
2402 | return 1; | |
2403 | } | |
fbb9ce95 | 2404 | |
8e18257d PZ |
2405 | static inline int separate_irq_context(struct task_struct *curr, |
2406 | struct held_lock *hlock) | |
2407 | { | |
2408 | return 0; | |
fbb9ce95 IM |
2409 | } |
2410 | ||
8e18257d | 2411 | #endif |
fbb9ce95 IM |
2412 | |
2413 | /* | |
8e18257d | 2414 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2415 | */ |
1d09daa5 | 2416 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2417 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2418 | { |
8e18257d | 2419 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2420 | |
2421 | /* | |
8e18257d PZ |
2422 | * If already set then do not dirty the cacheline, |
2423 | * nor do any checks: | |
fbb9ce95 | 2424 | */ |
f82b217e | 2425 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2426 | return 1; |
2427 | ||
2428 | if (!graph_lock()) | |
2429 | return 0; | |
fbb9ce95 | 2430 | /* |
8e18257d | 2431 | * Make sure we didnt race: |
fbb9ce95 | 2432 | */ |
f82b217e | 2433 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2434 | graph_unlock(); |
2435 | return 1; | |
2436 | } | |
fbb9ce95 | 2437 | |
f82b217e | 2438 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2439 | |
f82b217e | 2440 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2441 | return 0; |
fbb9ce95 | 2442 | |
8e18257d PZ |
2443 | switch (new_bit) { |
2444 | case LOCK_USED_IN_HARDIRQ: | |
2445 | case LOCK_USED_IN_SOFTIRQ: | |
2446 | case LOCK_USED_IN_HARDIRQ_READ: | |
2447 | case LOCK_USED_IN_SOFTIRQ_READ: | |
2448 | case LOCK_ENABLED_HARDIRQS: | |
2449 | case LOCK_ENABLED_SOFTIRQS: | |
2450 | case LOCK_ENABLED_HARDIRQS_READ: | |
2451 | case LOCK_ENABLED_SOFTIRQS_READ: | |
2452 | ret = mark_lock_irq(curr, this, new_bit); | |
2453 | if (!ret) | |
2454 | return 0; | |
2455 | break; | |
2456 | case LOCK_USED: | |
8e18257d PZ |
2457 | debug_atomic_dec(&nr_unused_locks); |
2458 | break; | |
2459 | default: | |
2460 | if (!debug_locks_off_graph_unlock()) | |
2461 | return 0; | |
2462 | WARN_ON(1); | |
2463 | return 0; | |
2464 | } | |
fbb9ce95 | 2465 | |
8e18257d PZ |
2466 | graph_unlock(); |
2467 | ||
2468 | /* | |
2469 | * We must printk outside of the graph_lock: | |
2470 | */ | |
2471 | if (ret == 2) { | |
2472 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2473 | print_lock(this); | |
2474 | print_irqtrace_events(curr); | |
2475 | dump_stack(); | |
2476 | } | |
2477 | ||
2478 | return ret; | |
2479 | } | |
fbb9ce95 IM |
2480 | |
2481 | /* | |
2482 | * Initialize a lock instance's lock-class mapping info: | |
2483 | */ | |
2484 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2485 | struct lock_class_key *key, int subclass) |
fbb9ce95 IM |
2486 | { |
2487 | if (unlikely(!debug_locks)) | |
2488 | return; | |
2489 | ||
2490 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2491 | return; | |
2492 | if (DEBUG_LOCKS_WARN_ON(!name)) | |
2493 | return; | |
2494 | /* | |
2495 | * Sanity check, the lock-class key must be persistent: | |
2496 | */ | |
2497 | if (!static_obj(key)) { | |
2498 | printk("BUG: key %p not in .data!\n", key); | |
2499 | DEBUG_LOCKS_WARN_ON(1); | |
2500 | return; | |
2501 | } | |
2502 | lock->name = name; | |
2503 | lock->key = key; | |
d6d897ce | 2504 | lock->class_cache = NULL; |
96645678 PZ |
2505 | #ifdef CONFIG_LOCK_STAT |
2506 | lock->cpu = raw_smp_processor_id(); | |
2507 | #endif | |
4dfbb9d8 PZ |
2508 | if (subclass) |
2509 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 IM |
2510 | } |
2511 | ||
2512 | EXPORT_SYMBOL_GPL(lockdep_init_map); | |
2513 | ||
2514 | /* | |
2515 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2516 | * We maintain the dependency maps and validate the locking attempt: | |
2517 | */ | |
2518 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2519 | int trylock, int read, int check, int hardirqs_off, | |
7531e2f3 | 2520 | struct lockdep_map *nest_lock, unsigned long ip) |
fbb9ce95 IM |
2521 | { |
2522 | struct task_struct *curr = current; | |
d6d897ce | 2523 | struct lock_class *class = NULL; |
fbb9ce95 | 2524 | struct held_lock *hlock; |
fbb9ce95 IM |
2525 | unsigned int depth, id; |
2526 | int chain_head = 0; | |
2527 | u64 chain_key; | |
2528 | ||
f20786ff PZ |
2529 | if (!prove_locking) |
2530 | check = 1; | |
2531 | ||
fbb9ce95 IM |
2532 | if (unlikely(!debug_locks)) |
2533 | return 0; | |
2534 | ||
2535 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2536 | return 0; | |
2537 | ||
2538 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2539 | debug_locks_off(); | |
2540 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2541 | printk("turning off the locking correctness validator.\n"); | |
2542 | return 0; | |
2543 | } | |
2544 | ||
d6d897ce IM |
2545 | if (!subclass) |
2546 | class = lock->class_cache; | |
2547 | /* | |
2548 | * Not cached yet or subclass? | |
2549 | */ | |
fbb9ce95 | 2550 | if (unlikely(!class)) { |
4dfbb9d8 | 2551 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2552 | if (!class) |
2553 | return 0; | |
2554 | } | |
2555 | debug_atomic_inc((atomic_t *)&class->ops); | |
2556 | if (very_verbose(class)) { | |
2557 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2558 | if (class->name_version > 1) | |
2559 | printk("#%d", class->name_version); | |
2560 | printk("\n"); | |
2561 | dump_stack(); | |
2562 | } | |
2563 | ||
2564 | /* | |
2565 | * Add the lock to the list of currently held locks. | |
2566 | * (we dont increase the depth just yet, up until the | |
2567 | * dependency checks are done) | |
2568 | */ | |
2569 | depth = curr->lockdep_depth; | |
2570 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2571 | return 0; | |
2572 | ||
2573 | hlock = curr->held_locks + depth; | |
f82b217e DJ |
2574 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2575 | return 0; | |
2576 | hlock->class_idx = class - lock_classes + 1; | |
fbb9ce95 IM |
2577 | hlock->acquire_ip = ip; |
2578 | hlock->instance = lock; | |
7531e2f3 | 2579 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2580 | hlock->trylock = trylock; |
2581 | hlock->read = read; | |
2582 | hlock->check = check; | |
6951b12a | 2583 | hlock->hardirqs_off = !!hardirqs_off; |
f20786ff PZ |
2584 | #ifdef CONFIG_LOCK_STAT |
2585 | hlock->waittime_stamp = 0; | |
2586 | hlock->holdtime_stamp = sched_clock(); | |
2587 | #endif | |
fbb9ce95 | 2588 | |
8e18257d PZ |
2589 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2590 | return 0; | |
2591 | ||
fbb9ce95 | 2592 | /* mark it as used: */ |
4ff773bb | 2593 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2594 | return 0; |
8e18257d | 2595 | |
fbb9ce95 | 2596 | /* |
17aacfb9 | 2597 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2598 | * lock keys along the dependency chain. We save the hash value |
2599 | * at every step so that we can get the current hash easily | |
2600 | * after unlock. The chain hash is then used to cache dependency | |
2601 | * results. | |
2602 | * | |
2603 | * The 'key ID' is what is the most compact key value to drive | |
2604 | * the hash, not class->key. | |
2605 | */ | |
2606 | id = class - lock_classes; | |
2607 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2608 | return 0; | |
2609 | ||
2610 | chain_key = curr->curr_chain_key; | |
2611 | if (!depth) { | |
2612 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2613 | return 0; | |
2614 | chain_head = 1; | |
2615 | } | |
2616 | ||
2617 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2618 | if (separate_irq_context(curr, hlock)) { |
2619 | chain_key = 0; | |
2620 | chain_head = 1; | |
fbb9ce95 | 2621 | } |
fbb9ce95 | 2622 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2623 | |
3aa416b0 | 2624 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2625 | return 0; |
381a2292 | 2626 | |
3aa416b0 | 2627 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2628 | curr->lockdep_depth++; |
2629 | check_chain_key(curr); | |
60e114d1 JP |
2630 | #ifdef CONFIG_DEBUG_LOCKDEP |
2631 | if (unlikely(!debug_locks)) | |
2632 | return 0; | |
2633 | #endif | |
fbb9ce95 IM |
2634 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2635 | debug_locks_off(); | |
2636 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2637 | printk("turning off the locking correctness validator.\n"); | |
2638 | return 0; | |
2639 | } | |
381a2292 | 2640 | |
fbb9ce95 IM |
2641 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2642 | max_lockdep_depth = curr->lockdep_depth; | |
2643 | ||
2644 | return 1; | |
2645 | } | |
2646 | ||
2647 | static int | |
2648 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2649 | unsigned long ip) | |
2650 | { | |
2651 | if (!debug_locks_off()) | |
2652 | return 0; | |
2653 | if (debug_locks_silent) | |
2654 | return 0; | |
2655 | ||
2656 | printk("\n=====================================\n"); | |
2657 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2658 | printk( "-------------------------------------\n"); | |
2659 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2660 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2661 | print_lockdep_cache(lock); |
2662 | printk(") at:\n"); | |
2663 | print_ip_sym(ip); | |
2664 | printk("but there are no more locks to release!\n"); | |
2665 | printk("\nother info that might help us debug this:\n"); | |
2666 | lockdep_print_held_locks(curr); | |
2667 | ||
2668 | printk("\nstack backtrace:\n"); | |
2669 | dump_stack(); | |
2670 | ||
2671 | return 0; | |
2672 | } | |
2673 | ||
2674 | /* | |
2675 | * Common debugging checks for both nested and non-nested unlock: | |
2676 | */ | |
2677 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2678 | unsigned long ip) | |
2679 | { | |
2680 | if (unlikely(!debug_locks)) | |
2681 | return 0; | |
2682 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2683 | return 0; | |
2684 | ||
2685 | if (curr->lockdep_depth <= 0) | |
2686 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2687 | ||
2688 | return 1; | |
2689 | } | |
2690 | ||
64aa348e PZ |
2691 | static int |
2692 | __lock_set_subclass(struct lockdep_map *lock, | |
2693 | unsigned int subclass, unsigned long ip) | |
2694 | { | |
2695 | struct task_struct *curr = current; | |
2696 | struct held_lock *hlock, *prev_hlock; | |
2697 | struct lock_class *class; | |
2698 | unsigned int depth; | |
2699 | int i; | |
2700 | ||
2701 | depth = curr->lockdep_depth; | |
2702 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2703 | return 0; | |
2704 | ||
2705 | prev_hlock = NULL; | |
2706 | for (i = depth-1; i >= 0; i--) { | |
2707 | hlock = curr->held_locks + i; | |
2708 | /* | |
2709 | * We must not cross into another context: | |
2710 | */ | |
2711 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2712 | break; | |
2713 | if (hlock->instance == lock) | |
2714 | goto found_it; | |
2715 | prev_hlock = hlock; | |
2716 | } | |
2717 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2718 | ||
2719 | found_it: | |
2720 | class = register_lock_class(lock, subclass, 0); | |
f82b217e | 2721 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2722 | |
2723 | curr->lockdep_depth = i; | |
2724 | curr->curr_chain_key = hlock->prev_chain_key; | |
2725 | ||
2726 | for (; i < depth; i++) { | |
2727 | hlock = curr->held_locks + i; | |
2728 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2729 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2730 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2731 | hlock->nest_lock, hlock->acquire_ip)) |
64aa348e PZ |
2732 | return 0; |
2733 | } | |
2734 | ||
2735 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2736 | return 0; | |
2737 | return 1; | |
2738 | } | |
2739 | ||
fbb9ce95 IM |
2740 | /* |
2741 | * Remove the lock to the list of currently held locks in a | |
2742 | * potentially non-nested (out of order) manner. This is a | |
2743 | * relatively rare operation, as all the unlock APIs default | |
2744 | * to nested mode (which uses lock_release()): | |
2745 | */ | |
2746 | static int | |
2747 | lock_release_non_nested(struct task_struct *curr, | |
2748 | struct lockdep_map *lock, unsigned long ip) | |
2749 | { | |
2750 | struct held_lock *hlock, *prev_hlock; | |
2751 | unsigned int depth; | |
2752 | int i; | |
2753 | ||
2754 | /* | |
2755 | * Check whether the lock exists in the current stack | |
2756 | * of held locks: | |
2757 | */ | |
2758 | depth = curr->lockdep_depth; | |
2759 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2760 | return 0; | |
2761 | ||
2762 | prev_hlock = NULL; | |
2763 | for (i = depth-1; i >= 0; i--) { | |
2764 | hlock = curr->held_locks + i; | |
2765 | /* | |
2766 | * We must not cross into another context: | |
2767 | */ | |
2768 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2769 | break; | |
2770 | if (hlock->instance == lock) | |
2771 | goto found_it; | |
2772 | prev_hlock = hlock; | |
2773 | } | |
2774 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2775 | ||
2776 | found_it: | |
f20786ff PZ |
2777 | lock_release_holdtime(hlock); |
2778 | ||
fbb9ce95 IM |
2779 | /* |
2780 | * We have the right lock to unlock, 'hlock' points to it. | |
2781 | * Now we remove it from the stack, and add back the other | |
2782 | * entries (if any), recalculating the hash along the way: | |
2783 | */ | |
2784 | curr->lockdep_depth = i; | |
2785 | curr->curr_chain_key = hlock->prev_chain_key; | |
2786 | ||
2787 | for (i++; i < depth; i++) { | |
2788 | hlock = curr->held_locks + i; | |
2789 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2790 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 2791 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2792 | hlock->nest_lock, hlock->acquire_ip)) |
fbb9ce95 IM |
2793 | return 0; |
2794 | } | |
2795 | ||
2796 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2797 | return 0; | |
2798 | return 1; | |
2799 | } | |
2800 | ||
2801 | /* | |
2802 | * Remove the lock to the list of currently held locks - this gets | |
2803 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2804 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2805 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2806 | */ | |
2807 | static int lock_release_nested(struct task_struct *curr, | |
2808 | struct lockdep_map *lock, unsigned long ip) | |
2809 | { | |
2810 | struct held_lock *hlock; | |
2811 | unsigned int depth; | |
2812 | ||
2813 | /* | |
2814 | * Pop off the top of the lock stack: | |
2815 | */ | |
2816 | depth = curr->lockdep_depth - 1; | |
2817 | hlock = curr->held_locks + depth; | |
2818 | ||
2819 | /* | |
2820 | * Is the unlock non-nested: | |
2821 | */ | |
2822 | if (hlock->instance != lock) | |
2823 | return lock_release_non_nested(curr, lock, ip); | |
2824 | curr->lockdep_depth--; | |
2825 | ||
2826 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2827 | return 0; | |
2828 | ||
2829 | curr->curr_chain_key = hlock->prev_chain_key; | |
2830 | ||
f20786ff PZ |
2831 | lock_release_holdtime(hlock); |
2832 | ||
fbb9ce95 IM |
2833 | #ifdef CONFIG_DEBUG_LOCKDEP |
2834 | hlock->prev_chain_key = 0; | |
f82b217e | 2835 | hlock->class_idx = 0; |
fbb9ce95 IM |
2836 | hlock->acquire_ip = 0; |
2837 | hlock->irq_context = 0; | |
2838 | #endif | |
2839 | return 1; | |
2840 | } | |
2841 | ||
2842 | /* | |
2843 | * Remove the lock to the list of currently held locks - this gets | |
2844 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2845 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2846 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2847 | */ | |
2848 | static void | |
2849 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2850 | { | |
2851 | struct task_struct *curr = current; | |
2852 | ||
2853 | if (!check_unlock(curr, lock, ip)) | |
2854 | return; | |
2855 | ||
2856 | if (nested) { | |
2857 | if (!lock_release_nested(curr, lock, ip)) | |
2858 | return; | |
2859 | } else { | |
2860 | if (!lock_release_non_nested(curr, lock, ip)) | |
2861 | return; | |
2862 | } | |
2863 | ||
2864 | check_chain_key(curr); | |
2865 | } | |
2866 | ||
2867 | /* | |
2868 | * Check whether we follow the irq-flags state precisely: | |
2869 | */ | |
1d09daa5 | 2870 | static void check_flags(unsigned long flags) |
fbb9ce95 | 2871 | { |
992860e9 IM |
2872 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
2873 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
2874 | if (!debug_locks) |
2875 | return; | |
2876 | ||
5f9fa8a6 IM |
2877 | if (irqs_disabled_flags(flags)) { |
2878 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
2879 | printk("possible reason: unannotated irqs-off.\n"); | |
2880 | } | |
2881 | } else { | |
2882 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
2883 | printk("possible reason: unannotated irqs-on.\n"); | |
2884 | } | |
2885 | } | |
fbb9ce95 IM |
2886 | |
2887 | /* | |
2888 | * We dont accurately track softirq state in e.g. | |
2889 | * hardirq contexts (such as on 4KSTACKS), so only | |
2890 | * check if not in hardirq contexts: | |
2891 | */ | |
2892 | if (!hardirq_count()) { | |
2893 | if (softirq_count()) | |
2894 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
2895 | else | |
2896 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
2897 | } | |
2898 | ||
2899 | if (!debug_locks) | |
2900 | print_irqtrace_events(current); | |
2901 | #endif | |
2902 | } | |
2903 | ||
64aa348e PZ |
2904 | void |
2905 | lock_set_subclass(struct lockdep_map *lock, | |
2906 | unsigned int subclass, unsigned long ip) | |
2907 | { | |
2908 | unsigned long flags; | |
2909 | ||
2910 | if (unlikely(current->lockdep_recursion)) | |
2911 | return; | |
2912 | ||
2913 | raw_local_irq_save(flags); | |
2914 | current->lockdep_recursion = 1; | |
2915 | check_flags(flags); | |
2916 | if (__lock_set_subclass(lock, subclass, ip)) | |
2917 | check_chain_key(current); | |
2918 | current->lockdep_recursion = 0; | |
2919 | raw_local_irq_restore(flags); | |
2920 | } | |
2921 | ||
2922 | EXPORT_SYMBOL_GPL(lock_set_subclass); | |
2923 | ||
fbb9ce95 IM |
2924 | /* |
2925 | * We are not always called with irqs disabled - do that here, | |
2926 | * and also avoid lockdep recursion: | |
2927 | */ | |
1d09daa5 | 2928 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
2929 | int trylock, int read, int check, |
2930 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
2931 | { |
2932 | unsigned long flags; | |
2933 | ||
2934 | if (unlikely(current->lockdep_recursion)) | |
2935 | return; | |
2936 | ||
2937 | raw_local_irq_save(flags); | |
2938 | check_flags(flags); | |
2939 | ||
2940 | current->lockdep_recursion = 1; | |
2941 | __lock_acquire(lock, subclass, trylock, read, check, | |
7531e2f3 | 2942 | irqs_disabled_flags(flags), nest_lock, ip); |
fbb9ce95 IM |
2943 | current->lockdep_recursion = 0; |
2944 | raw_local_irq_restore(flags); | |
2945 | } | |
2946 | ||
2947 | EXPORT_SYMBOL_GPL(lock_acquire); | |
2948 | ||
1d09daa5 | 2949 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 2950 | unsigned long ip) |
fbb9ce95 IM |
2951 | { |
2952 | unsigned long flags; | |
2953 | ||
2954 | if (unlikely(current->lockdep_recursion)) | |
2955 | return; | |
2956 | ||
2957 | raw_local_irq_save(flags); | |
2958 | check_flags(flags); | |
2959 | current->lockdep_recursion = 1; | |
2960 | __lock_release(lock, nested, ip); | |
2961 | current->lockdep_recursion = 0; | |
2962 | raw_local_irq_restore(flags); | |
2963 | } | |
2964 | ||
2965 | EXPORT_SYMBOL_GPL(lock_release); | |
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; | |
3002 | int i, point; | |
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 | ||
f82b217e | 3026 | point = lock_contention_point(hlock_class(hlock), ip); |
f20786ff | 3027 | |
f82b217e | 3028 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff | 3029 | if (point < ARRAY_SIZE(stats->contention_point)) |
04148b73 | 3030 | stats->contention_point[point]++; |
96645678 PZ |
3031 | if (lock->cpu != smp_processor_id()) |
3032 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3033 | put_lock_stats(stats); |
3034 | } | |
3035 | ||
3036 | static void | |
3037 | __lock_acquired(struct lockdep_map *lock) | |
3038 | { | |
3039 | struct task_struct *curr = current; | |
3040 | struct held_lock *hlock, *prev_hlock; | |
3041 | struct lock_class_stats *stats; | |
3042 | unsigned int depth; | |
3043 | u64 now; | |
96645678 PZ |
3044 | s64 waittime = 0; |
3045 | int i, cpu; | |
f20786ff PZ |
3046 | |
3047 | depth = curr->lockdep_depth; | |
3048 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3049 | return; | |
3050 | ||
3051 | prev_hlock = NULL; | |
3052 | for (i = depth-1; i >= 0; i--) { | |
3053 | hlock = curr->held_locks + i; | |
3054 | /* | |
3055 | * We must not cross into another context: | |
3056 | */ | |
3057 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3058 | break; | |
3059 | if (hlock->instance == lock) | |
3060 | goto found_it; | |
3061 | prev_hlock = hlock; | |
3062 | } | |
3063 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3064 | return; | |
3065 | ||
3066 | found_it: | |
96645678 PZ |
3067 | cpu = smp_processor_id(); |
3068 | if (hlock->waittime_stamp) { | |
3069 | now = sched_clock(); | |
3070 | waittime = now - hlock->waittime_stamp; | |
3071 | hlock->holdtime_stamp = now; | |
3072 | } | |
f20786ff | 3073 | |
f82b217e | 3074 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3075 | if (waittime) { |
3076 | if (hlock->read) | |
3077 | lock_time_inc(&stats->read_waittime, waittime); | |
3078 | else | |
3079 | lock_time_inc(&stats->write_waittime, waittime); | |
3080 | } | |
3081 | if (lock->cpu != cpu) | |
3082 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3083 | put_lock_stats(stats); |
96645678 PZ |
3084 | |
3085 | lock->cpu = cpu; | |
f20786ff PZ |
3086 | } |
3087 | ||
3088 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3089 | { | |
3090 | unsigned long flags; | |
3091 | ||
3092 | if (unlikely(!lock_stat)) | |
3093 | return; | |
3094 | ||
3095 | if (unlikely(current->lockdep_recursion)) | |
3096 | return; | |
3097 | ||
3098 | raw_local_irq_save(flags); | |
3099 | check_flags(flags); | |
3100 | current->lockdep_recursion = 1; | |
3101 | __lock_contended(lock, ip); | |
3102 | current->lockdep_recursion = 0; | |
3103 | raw_local_irq_restore(flags); | |
3104 | } | |
3105 | EXPORT_SYMBOL_GPL(lock_contended); | |
3106 | ||
3107 | void lock_acquired(struct lockdep_map *lock) | |
3108 | { | |
3109 | unsigned long flags; | |
3110 | ||
3111 | if (unlikely(!lock_stat)) | |
3112 | return; | |
3113 | ||
3114 | if (unlikely(current->lockdep_recursion)) | |
3115 | return; | |
3116 | ||
3117 | raw_local_irq_save(flags); | |
3118 | check_flags(flags); | |
3119 | current->lockdep_recursion = 1; | |
3120 | __lock_acquired(lock); | |
3121 | current->lockdep_recursion = 0; | |
3122 | raw_local_irq_restore(flags); | |
3123 | } | |
3124 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3125 | #endif | |
3126 | ||
fbb9ce95 IM |
3127 | /* |
3128 | * Used by the testsuite, sanitize the validator state | |
3129 | * after a simulated failure: | |
3130 | */ | |
3131 | ||
3132 | void lockdep_reset(void) | |
3133 | { | |
3134 | unsigned long flags; | |
23d95a03 | 3135 | int i; |
fbb9ce95 IM |
3136 | |
3137 | raw_local_irq_save(flags); | |
3138 | current->curr_chain_key = 0; | |
3139 | current->lockdep_depth = 0; | |
3140 | current->lockdep_recursion = 0; | |
3141 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3142 | nr_hardirq_chains = 0; | |
3143 | nr_softirq_chains = 0; | |
3144 | nr_process_chains = 0; | |
3145 | debug_locks = 1; | |
23d95a03 IM |
3146 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3147 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3148 | raw_local_irq_restore(flags); |
3149 | } | |
3150 | ||
3151 | static void zap_class(struct lock_class *class) | |
3152 | { | |
3153 | int i; | |
3154 | ||
3155 | /* | |
3156 | * Remove all dependencies this lock is | |
3157 | * involved in: | |
3158 | */ | |
3159 | for (i = 0; i < nr_list_entries; i++) { | |
3160 | if (list_entries[i].class == class) | |
3161 | list_del_rcu(&list_entries[i].entry); | |
3162 | } | |
3163 | /* | |
3164 | * Unhash the class and remove it from the all_lock_classes list: | |
3165 | */ | |
3166 | list_del_rcu(&class->hash_entry); | |
3167 | list_del_rcu(&class->lock_entry); | |
3168 | ||
8bfe0298 | 3169 | class->key = NULL; |
fbb9ce95 IM |
3170 | } |
3171 | ||
fabe874a | 3172 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3173 | { |
3174 | return addr >= start && addr < start + size; | |
3175 | } | |
3176 | ||
3177 | void lockdep_free_key_range(void *start, unsigned long size) | |
3178 | { | |
3179 | struct lock_class *class, *next; | |
3180 | struct list_head *head; | |
3181 | unsigned long flags; | |
3182 | int i; | |
5a26db5b | 3183 | int locked; |
fbb9ce95 IM |
3184 | |
3185 | raw_local_irq_save(flags); | |
5a26db5b | 3186 | locked = graph_lock(); |
fbb9ce95 IM |
3187 | |
3188 | /* | |
3189 | * Unhash all classes that were created by this module: | |
3190 | */ | |
3191 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3192 | head = classhash_table + i; | |
3193 | if (list_empty(head)) | |
3194 | continue; | |
fabe874a | 3195 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3196 | if (within(class->key, start, size)) |
3197 | zap_class(class); | |
fabe874a AV |
3198 | else if (within(class->name, start, size)) |
3199 | zap_class(class); | |
3200 | } | |
fbb9ce95 IM |
3201 | } |
3202 | ||
5a26db5b NP |
3203 | if (locked) |
3204 | graph_unlock(); | |
fbb9ce95 IM |
3205 | raw_local_irq_restore(flags); |
3206 | } | |
3207 | ||
3208 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3209 | { | |
d6d897ce | 3210 | struct lock_class *class, *next; |
fbb9ce95 IM |
3211 | struct list_head *head; |
3212 | unsigned long flags; | |
3213 | int i, j; | |
5a26db5b | 3214 | int locked; |
fbb9ce95 IM |
3215 | |
3216 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3217 | |
3218 | /* | |
d6d897ce IM |
3219 | * Remove all classes this lock might have: |
3220 | */ | |
3221 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3222 | /* | |
3223 | * If the class exists we look it up and zap it: | |
3224 | */ | |
3225 | class = look_up_lock_class(lock, j); | |
3226 | if (class) | |
3227 | zap_class(class); | |
3228 | } | |
3229 | /* | |
3230 | * Debug check: in the end all mapped classes should | |
3231 | * be gone. | |
fbb9ce95 | 3232 | */ |
5a26db5b | 3233 | locked = graph_lock(); |
fbb9ce95 IM |
3234 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3235 | head = classhash_table + i; | |
3236 | if (list_empty(head)) | |
3237 | continue; | |
3238 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3239 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3240 | if (debug_locks_off_graph_unlock()) |
3241 | WARN_ON(1); | |
d6d897ce | 3242 | goto out_restore; |
fbb9ce95 IM |
3243 | } |
3244 | } | |
3245 | } | |
5a26db5b NP |
3246 | if (locked) |
3247 | graph_unlock(); | |
d6d897ce IM |
3248 | |
3249 | out_restore: | |
fbb9ce95 IM |
3250 | raw_local_irq_restore(flags); |
3251 | } | |
3252 | ||
1499993c | 3253 | void lockdep_init(void) |
fbb9ce95 IM |
3254 | { |
3255 | int i; | |
3256 | ||
3257 | /* | |
3258 | * Some architectures have their own start_kernel() | |
3259 | * code which calls lockdep_init(), while we also | |
3260 | * call lockdep_init() from the start_kernel() itself, | |
3261 | * and we want to initialize the hashes only once: | |
3262 | */ | |
3263 | if (lockdep_initialized) | |
3264 | return; | |
3265 | ||
3266 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3267 | INIT_LIST_HEAD(classhash_table + i); | |
3268 | ||
3269 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3270 | INIT_LIST_HEAD(chainhash_table + i); | |
3271 | ||
3272 | lockdep_initialized = 1; | |
3273 | } | |
3274 | ||
3275 | void __init lockdep_info(void) | |
3276 | { | |
3277 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3278 | ||
3279 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); | |
3280 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); | |
3281 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
3282 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); | |
3283 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); | |
3284 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3285 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3286 | ||
3287 | printk(" memory used by lock dependency info: %lu kB\n", | |
3288 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3289 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3290 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3291 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
3292 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
3293 | ||
3294 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3295 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3296 | ||
3297 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3298 | if (lockdep_init_error) { |
3299 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3300 | printk("Call stack leading to lockdep invocation was:\n"); | |
3301 | print_stack_trace(&lockdep_init_trace, 0); | |
3302 | } | |
fbb9ce95 IM |
3303 | #endif |
3304 | } | |
3305 | ||
fbb9ce95 IM |
3306 | static void |
3307 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3308 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3309 | { |
3310 | if (!debug_locks_off()) | |
3311 | return; | |
3312 | if (debug_locks_silent) | |
3313 | return; | |
3314 | ||
3315 | printk("\n=========================\n"); | |
3316 | printk( "[ BUG: held lock freed! ]\n"); | |
3317 | printk( "-------------------------\n"); | |
3318 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3319 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3320 | print_lock(hlock); |
fbb9ce95 IM |
3321 | lockdep_print_held_locks(curr); |
3322 | ||
3323 | printk("\nstack backtrace:\n"); | |
3324 | dump_stack(); | |
3325 | } | |
3326 | ||
54561783 ON |
3327 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3328 | const void* lock_from, unsigned long lock_len) | |
3329 | { | |
3330 | return lock_from + lock_len <= mem_from || | |
3331 | mem_from + mem_len <= lock_from; | |
3332 | } | |
3333 | ||
fbb9ce95 IM |
3334 | /* |
3335 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3336 | * is destroyed or reinitialized - this code checks whether there is | |
3337 | * any held lock in the memory range of <from> to <to>: | |
3338 | */ | |
3339 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3340 | { | |
fbb9ce95 IM |
3341 | struct task_struct *curr = current; |
3342 | struct held_lock *hlock; | |
3343 | unsigned long flags; | |
3344 | int i; | |
3345 | ||
3346 | if (unlikely(!debug_locks)) | |
3347 | return; | |
3348 | ||
3349 | local_irq_save(flags); | |
3350 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3351 | hlock = curr->held_locks + i; | |
3352 | ||
54561783 ON |
3353 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3354 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3355 | continue; |
3356 | ||
54561783 | 3357 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3358 | break; |
3359 | } | |
3360 | local_irq_restore(flags); | |
3361 | } | |
ed07536e | 3362 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3363 | |
3364 | static void print_held_locks_bug(struct task_struct *curr) | |
3365 | { | |
3366 | if (!debug_locks_off()) | |
3367 | return; | |
3368 | if (debug_locks_silent) | |
3369 | return; | |
3370 | ||
3371 | printk("\n=====================================\n"); | |
3372 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3373 | printk( "-------------------------------------\n"); | |
3374 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3375 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3376 | lockdep_print_held_locks(curr); |
3377 | ||
3378 | printk("\nstack backtrace:\n"); | |
3379 | dump_stack(); | |
3380 | } | |
3381 | ||
3382 | void debug_check_no_locks_held(struct task_struct *task) | |
3383 | { | |
3384 | if (unlikely(task->lockdep_depth > 0)) | |
3385 | print_held_locks_bug(task); | |
3386 | } | |
3387 | ||
3388 | void debug_show_all_locks(void) | |
3389 | { | |
3390 | struct task_struct *g, *p; | |
3391 | int count = 10; | |
3392 | int unlock = 1; | |
3393 | ||
9c35dd7f JP |
3394 | if (unlikely(!debug_locks)) { |
3395 | printk("INFO: lockdep is turned off.\n"); | |
3396 | return; | |
3397 | } | |
fbb9ce95 IM |
3398 | printk("\nShowing all locks held in the system:\n"); |
3399 | ||
3400 | /* | |
3401 | * Here we try to get the tasklist_lock as hard as possible, | |
3402 | * if not successful after 2 seconds we ignore it (but keep | |
3403 | * trying). This is to enable a debug printout even if a | |
3404 | * tasklist_lock-holding task deadlocks or crashes. | |
3405 | */ | |
3406 | retry: | |
3407 | if (!read_trylock(&tasklist_lock)) { | |
3408 | if (count == 10) | |
3409 | printk("hm, tasklist_lock locked, retrying... "); | |
3410 | if (count) { | |
3411 | count--; | |
3412 | printk(" #%d", 10-count); | |
3413 | mdelay(200); | |
3414 | goto retry; | |
3415 | } | |
3416 | printk(" ignoring it.\n"); | |
3417 | unlock = 0; | |
46fec7ac | 3418 | } else { |
3419 | if (count != 10) | |
3420 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3421 | } |
fbb9ce95 IM |
3422 | |
3423 | do_each_thread(g, p) { | |
85684873 IM |
3424 | /* |
3425 | * It's not reliable to print a task's held locks | |
3426 | * if it's not sleeping (or if it's not the current | |
3427 | * task): | |
3428 | */ | |
3429 | if (p->state == TASK_RUNNING && p != current) | |
3430 | continue; | |
fbb9ce95 IM |
3431 | if (p->lockdep_depth) |
3432 | lockdep_print_held_locks(p); | |
3433 | if (!unlock) | |
3434 | if (read_trylock(&tasklist_lock)) | |
3435 | unlock = 1; | |
3436 | } while_each_thread(g, p); | |
3437 | ||
3438 | printk("\n"); | |
3439 | printk("=============================================\n\n"); | |
3440 | ||
3441 | if (unlock) | |
3442 | read_unlock(&tasklist_lock); | |
3443 | } | |
3444 | ||
3445 | EXPORT_SYMBOL_GPL(debug_show_all_locks); | |
3446 | ||
82a1fcb9 IM |
3447 | /* |
3448 | * Careful: only use this function if you are sure that | |
3449 | * the task cannot run in parallel! | |
3450 | */ | |
3451 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3452 | { |
9c35dd7f JP |
3453 | if (unlikely(!debug_locks)) { |
3454 | printk("INFO: lockdep is turned off.\n"); | |
3455 | return; | |
3456 | } | |
fbb9ce95 IM |
3457 | lockdep_print_held_locks(task); |
3458 | } | |
82a1fcb9 IM |
3459 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3460 | ||
3461 | void debug_show_held_locks(struct task_struct *task) | |
3462 | { | |
3463 | __debug_show_held_locks(task); | |
3464 | } | |
fbb9ce95 IM |
3465 | |
3466 | EXPORT_SYMBOL_GPL(debug_show_held_locks); | |
b351d164 PZ |
3467 | |
3468 | void lockdep_sys_exit(void) | |
3469 | { | |
3470 | struct task_struct *curr = current; | |
3471 | ||
3472 | if (unlikely(curr->lockdep_depth)) { | |
3473 | if (!debug_locks_off()) | |
3474 | return; | |
3475 | printk("\n================================================\n"); | |
3476 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3477 | printk( "------------------------------------------------\n"); | |
3478 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3479 | curr->comm, curr->pid); | |
3480 | lockdep_print_held_locks(curr); | |
3481 | } | |
3482 | } |