Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
fbb9ce95 IM |
44 | |
45 | #include <asm/sections.h> | |
46 | ||
47 | #include "lockdep_internals.h" | |
48 | ||
f20786ff PZ |
49 | #ifdef CONFIG_PROVE_LOCKING |
50 | int prove_locking = 1; | |
51 | module_param(prove_locking, int, 0644); | |
52 | #else | |
53 | #define prove_locking 0 | |
54 | #endif | |
55 | ||
56 | #ifdef CONFIG_LOCK_STAT | |
57 | int lock_stat = 1; | |
58 | module_param(lock_stat, int, 0644); | |
59 | #else | |
60 | #define lock_stat 0 | |
61 | #endif | |
62 | ||
fbb9ce95 | 63 | /* |
74c383f1 IM |
64 | * lockdep_lock: protects the lockdep graph, the hashes and the |
65 | * class/list/hash allocators. | |
fbb9ce95 IM |
66 | * |
67 | * This is one of the rare exceptions where it's justified | |
68 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 69 | * code to recurse back into the lockdep code... |
fbb9ce95 | 70 | */ |
74c383f1 IM |
71 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
72 | ||
73 | static int graph_lock(void) | |
74 | { | |
75 | __raw_spin_lock(&lockdep_lock); | |
76 | /* | |
77 | * Make sure that if another CPU detected a bug while | |
78 | * walking the graph we dont change it (while the other | |
79 | * CPU is busy printing out stuff with the graph lock | |
80 | * dropped already) | |
81 | */ | |
82 | if (!debug_locks) { | |
83 | __raw_spin_unlock(&lockdep_lock); | |
84 | return 0; | |
85 | } | |
bb065afb SR |
86 | /* prevent any recursions within lockdep from causing deadlocks */ |
87 | current->lockdep_recursion++; | |
74c383f1 IM |
88 | return 1; |
89 | } | |
90 | ||
91 | static inline int graph_unlock(void) | |
92 | { | |
381a2292 JP |
93 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
94 | return DEBUG_LOCKS_WARN_ON(1); | |
95 | ||
bb065afb | 96 | current->lockdep_recursion--; |
74c383f1 IM |
97 | __raw_spin_unlock(&lockdep_lock); |
98 | return 0; | |
99 | } | |
100 | ||
101 | /* | |
102 | * Turn lock debugging off and return with 0 if it was off already, | |
103 | * and also release the graph lock: | |
104 | */ | |
105 | static inline int debug_locks_off_graph_unlock(void) | |
106 | { | |
107 | int ret = debug_locks_off(); | |
108 | ||
109 | __raw_spin_unlock(&lockdep_lock); | |
110 | ||
111 | return ret; | |
112 | } | |
fbb9ce95 IM |
113 | |
114 | static int lockdep_initialized; | |
115 | ||
116 | unsigned long nr_list_entries; | |
117 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; | |
118 | ||
fbb9ce95 IM |
119 | /* |
120 | * All data structures here are protected by the global debug_lock. | |
121 | * | |
122 | * Mutex key structs only get allocated, once during bootup, and never | |
123 | * get freed - this significantly simplifies the debugging code. | |
124 | */ | |
125 | unsigned long nr_lock_classes; | |
126 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
127 | ||
f82b217e DJ |
128 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
129 | { | |
130 | if (!hlock->class_idx) { | |
131 | DEBUG_LOCKS_WARN_ON(1); | |
132 | return NULL; | |
133 | } | |
134 | return lock_classes + hlock->class_idx - 1; | |
135 | } | |
136 | ||
f20786ff PZ |
137 | #ifdef CONFIG_LOCK_STAT |
138 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); | |
139 | ||
140 | static int lock_contention_point(struct lock_class *class, unsigned long ip) | |
141 | { | |
142 | int i; | |
143 | ||
144 | for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) { | |
145 | if (class->contention_point[i] == 0) { | |
146 | class->contention_point[i] = ip; | |
147 | break; | |
148 | } | |
149 | if (class->contention_point[i] == ip) | |
150 | break; | |
151 | } | |
152 | ||
153 | return i; | |
154 | } | |
155 | ||
156 | static void lock_time_inc(struct lock_time *lt, s64 time) | |
157 | { | |
158 | if (time > lt->max) | |
159 | lt->max = time; | |
160 | ||
161 | if (time < lt->min || !lt->min) | |
162 | lt->min = time; | |
163 | ||
164 | lt->total += time; | |
165 | lt->nr++; | |
166 | } | |
167 | ||
c46261de PZ |
168 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
169 | { | |
170 | dst->min += src->min; | |
171 | dst->max += src->max; | |
172 | dst->total += src->total; | |
173 | dst->nr += src->nr; | |
174 | } | |
175 | ||
176 | struct lock_class_stats lock_stats(struct lock_class *class) | |
177 | { | |
178 | struct lock_class_stats stats; | |
179 | int cpu, i; | |
180 | ||
181 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
182 | for_each_possible_cpu(cpu) { | |
183 | struct lock_class_stats *pcs = | |
184 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
185 | ||
186 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
187 | stats.contention_point[i] += pcs->contention_point[i]; | |
188 | ||
189 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); | |
190 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
191 | ||
192 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
193 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
194 | |
195 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
196 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
197 | } |
198 | ||
199 | return stats; | |
200 | } | |
201 | ||
202 | void clear_lock_stats(struct lock_class *class) | |
203 | { | |
204 | int cpu; | |
205 | ||
206 | for_each_possible_cpu(cpu) { | |
207 | struct lock_class_stats *cpu_stats = | |
208 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
209 | ||
210 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
211 | } | |
212 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
213 | } | |
214 | ||
f20786ff PZ |
215 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
216 | { | |
217 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
218 | } | |
219 | ||
220 | static void put_lock_stats(struct lock_class_stats *stats) | |
221 | { | |
222 | put_cpu_var(lock_stats); | |
223 | } | |
224 | ||
225 | static void lock_release_holdtime(struct held_lock *hlock) | |
226 | { | |
227 | struct lock_class_stats *stats; | |
228 | s64 holdtime; | |
229 | ||
230 | if (!lock_stat) | |
231 | return; | |
232 | ||
233 | holdtime = sched_clock() - hlock->holdtime_stamp; | |
234 | ||
f82b217e | 235 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
236 | if (hlock->read) |
237 | lock_time_inc(&stats->read_holdtime, holdtime); | |
238 | else | |
239 | lock_time_inc(&stats->write_holdtime, holdtime); | |
240 | put_lock_stats(stats); | |
241 | } | |
242 | #else | |
243 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
244 | { | |
245 | } | |
246 | #endif | |
247 | ||
fbb9ce95 IM |
248 | /* |
249 | * We keep a global list of all lock classes. The list only grows, | |
250 | * never shrinks. The list is only accessed with the lockdep | |
251 | * spinlock lock held. | |
252 | */ | |
253 | LIST_HEAD(all_lock_classes); | |
254 | ||
255 | /* | |
256 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
257 | */ | |
258 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
259 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 260 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
261 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
262 | ||
263 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
264 | ||
fbb9ce95 IM |
265 | /* |
266 | * We put the lock dependency chains into a hash-table as well, to cache | |
267 | * their existence: | |
268 | */ | |
269 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
270 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 271 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
272 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
273 | ||
274 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
275 | ||
276 | /* | |
277 | * The hash key of the lock dependency chains is a hash itself too: | |
278 | * it's a hash of all locks taken up to that lock, including that lock. | |
279 | * It's a 64-bit hash, because it's important for the keys to be | |
280 | * unique. | |
281 | */ | |
282 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
283 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
284 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
285 | (key2)) |
286 | ||
1d09daa5 | 287 | void lockdep_off(void) |
fbb9ce95 IM |
288 | { |
289 | current->lockdep_recursion++; | |
290 | } | |
291 | ||
292 | EXPORT_SYMBOL(lockdep_off); | |
293 | ||
1d09daa5 | 294 | void lockdep_on(void) |
fbb9ce95 IM |
295 | { |
296 | current->lockdep_recursion--; | |
297 | } | |
298 | ||
299 | EXPORT_SYMBOL(lockdep_on); | |
300 | ||
fbb9ce95 IM |
301 | /* |
302 | * Debugging switches: | |
303 | */ | |
304 | ||
305 | #define VERBOSE 0 | |
33e94e96 | 306 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
307 | |
308 | #if VERBOSE | |
309 | # define HARDIRQ_VERBOSE 1 | |
310 | # define SOFTIRQ_VERBOSE 1 | |
311 | #else | |
312 | # define HARDIRQ_VERBOSE 0 | |
313 | # define SOFTIRQ_VERBOSE 0 | |
314 | #endif | |
315 | ||
316 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE | |
317 | /* | |
318 | * Quick filtering for interesting events: | |
319 | */ | |
320 | static int class_filter(struct lock_class *class) | |
321 | { | |
f9829cce AK |
322 | #if 0 |
323 | /* Example */ | |
fbb9ce95 | 324 | if (class->name_version == 1 && |
f9829cce | 325 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
326 | return 1; |
327 | if (class->name_version == 1 && | |
f9829cce | 328 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 329 | return 1; |
f9829cce | 330 | #endif |
a6640897 IM |
331 | /* Filter everything else. 1 would be to allow everything else */ |
332 | return 0; | |
fbb9ce95 IM |
333 | } |
334 | #endif | |
335 | ||
336 | static int verbose(struct lock_class *class) | |
337 | { | |
338 | #if VERBOSE | |
339 | return class_filter(class); | |
340 | #endif | |
341 | return 0; | |
342 | } | |
343 | ||
fbb9ce95 IM |
344 | /* |
345 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 346 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
347 | */ |
348 | unsigned long nr_stack_trace_entries; | |
349 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
350 | ||
351 | static int save_trace(struct stack_trace *trace) | |
352 | { | |
353 | trace->nr_entries = 0; | |
354 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
355 | trace->entries = stack_trace + nr_stack_trace_entries; | |
356 | ||
5a1b3999 | 357 | trace->skip = 3; |
5a1b3999 | 358 | |
ab1b6f03 | 359 | save_stack_trace(trace); |
fbb9ce95 IM |
360 | |
361 | trace->max_entries = trace->nr_entries; | |
362 | ||
363 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
364 | |
365 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
366 | if (!debug_locks_off_graph_unlock()) |
367 | return 0; | |
368 | ||
369 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
370 | printk("turning off the locking correctness validator.\n"); | |
371 | dump_stack(); | |
372 | ||
fbb9ce95 IM |
373 | return 0; |
374 | } | |
375 | ||
376 | return 1; | |
377 | } | |
378 | ||
379 | unsigned int nr_hardirq_chains; | |
380 | unsigned int nr_softirq_chains; | |
381 | unsigned int nr_process_chains; | |
382 | unsigned int max_lockdep_depth; | |
383 | unsigned int max_recursion_depth; | |
384 | ||
419ca3f1 DM |
385 | static unsigned int lockdep_dependency_gen_id; |
386 | ||
387 | static bool lockdep_dependency_visit(struct lock_class *source, | |
388 | unsigned int depth) | |
389 | { | |
390 | if (!depth) | |
391 | lockdep_dependency_gen_id++; | |
392 | if (source->dep_gen_id == lockdep_dependency_gen_id) | |
393 | return true; | |
394 | source->dep_gen_id = lockdep_dependency_gen_id; | |
395 | return false; | |
396 | } | |
397 | ||
fbb9ce95 IM |
398 | #ifdef CONFIG_DEBUG_LOCKDEP |
399 | /* | |
400 | * We cannot printk in early bootup code. Not even early_printk() | |
401 | * might work. So we mark any initialization errors and printk | |
402 | * about it later on, in lockdep_info(). | |
403 | */ | |
404 | static int lockdep_init_error; | |
c71063c9 JB |
405 | static unsigned long lockdep_init_trace_data[20]; |
406 | static struct stack_trace lockdep_init_trace = { | |
407 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
408 | .entries = lockdep_init_trace_data, | |
409 | }; | |
fbb9ce95 IM |
410 | |
411 | /* | |
412 | * Various lockdep statistics: | |
413 | */ | |
414 | atomic_t chain_lookup_hits; | |
415 | atomic_t chain_lookup_misses; | |
416 | atomic_t hardirqs_on_events; | |
417 | atomic_t hardirqs_off_events; | |
418 | atomic_t redundant_hardirqs_on; | |
419 | atomic_t redundant_hardirqs_off; | |
420 | atomic_t softirqs_on_events; | |
421 | atomic_t softirqs_off_events; | |
422 | atomic_t redundant_softirqs_on; | |
423 | atomic_t redundant_softirqs_off; | |
424 | atomic_t nr_unused_locks; | |
425 | atomic_t nr_cyclic_checks; | |
426 | atomic_t nr_cyclic_check_recursions; | |
427 | atomic_t nr_find_usage_forwards_checks; | |
428 | atomic_t nr_find_usage_forwards_recursions; | |
429 | atomic_t nr_find_usage_backwards_checks; | |
430 | atomic_t nr_find_usage_backwards_recursions; | |
431 | # define debug_atomic_inc(ptr) atomic_inc(ptr) | |
432 | # define debug_atomic_dec(ptr) atomic_dec(ptr) | |
433 | # define debug_atomic_read(ptr) atomic_read(ptr) | |
434 | #else | |
435 | # define debug_atomic_inc(ptr) do { } while (0) | |
436 | # define debug_atomic_dec(ptr) do { } while (0) | |
437 | # define debug_atomic_read(ptr) 0 | |
438 | #endif | |
439 | ||
440 | /* | |
441 | * Locking printouts: | |
442 | */ | |
443 | ||
444 | static const char *usage_str[] = | |
445 | { | |
446 | [LOCK_USED] = "initial-use ", | |
447 | [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W", | |
448 | [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W", | |
449 | [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W", | |
450 | [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W", | |
451 | [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R", | |
452 | [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R", | |
453 | [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R", | |
454 | [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R", | |
455 | }; | |
456 | ||
457 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
458 | { | |
ffb45122 | 459 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
460 | } |
461 | ||
462 | void | |
463 | get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4) | |
464 | { | |
465 | *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.'; | |
466 | ||
467 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) | |
468 | *c1 = '+'; | |
469 | else | |
470 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) | |
471 | *c1 = '-'; | |
472 | ||
473 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) | |
474 | *c2 = '+'; | |
475 | else | |
476 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) | |
477 | *c2 = '-'; | |
478 | ||
479 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
480 | *c3 = '-'; | |
481 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { | |
482 | *c3 = '+'; | |
483 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
484 | *c3 = '?'; | |
485 | } | |
486 | ||
487 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
488 | *c4 = '-'; | |
489 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { | |
490 | *c4 = '+'; | |
491 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
492 | *c4 = '?'; | |
493 | } | |
494 | } | |
495 | ||
496 | static void print_lock_name(struct lock_class *class) | |
497 | { | |
9281acea | 498 | char str[KSYM_NAME_LEN], c1, c2, c3, c4; |
fbb9ce95 IM |
499 | const char *name; |
500 | ||
501 | get_usage_chars(class, &c1, &c2, &c3, &c4); | |
502 | ||
503 | name = class->name; | |
504 | if (!name) { | |
505 | name = __get_key_name(class->key, str); | |
506 | printk(" (%s", name); | |
507 | } else { | |
508 | printk(" (%s", name); | |
509 | if (class->name_version > 1) | |
510 | printk("#%d", class->name_version); | |
511 | if (class->subclass) | |
512 | printk("/%d", class->subclass); | |
513 | } | |
514 | printk("){%c%c%c%c}", c1, c2, c3, c4); | |
515 | } | |
516 | ||
517 | static void print_lockdep_cache(struct lockdep_map *lock) | |
518 | { | |
519 | const char *name; | |
9281acea | 520 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
521 | |
522 | name = lock->name; | |
523 | if (!name) | |
524 | name = __get_key_name(lock->key->subkeys, str); | |
525 | ||
526 | printk("%s", name); | |
527 | } | |
528 | ||
529 | static void print_lock(struct held_lock *hlock) | |
530 | { | |
f82b217e | 531 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
532 | printk(", at: "); |
533 | print_ip_sym(hlock->acquire_ip); | |
534 | } | |
535 | ||
536 | static void lockdep_print_held_locks(struct task_struct *curr) | |
537 | { | |
538 | int i, depth = curr->lockdep_depth; | |
539 | ||
540 | if (!depth) { | |
ba25f9dc | 541 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
542 | return; |
543 | } | |
544 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 545 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
546 | |
547 | for (i = 0; i < depth; i++) { | |
548 | printk(" #%d: ", i); | |
549 | print_lock(curr->held_locks + i); | |
550 | } | |
551 | } | |
fbb9ce95 IM |
552 | |
553 | static void print_lock_class_header(struct lock_class *class, int depth) | |
554 | { | |
555 | int bit; | |
556 | ||
f9829cce | 557 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
558 | print_lock_name(class); |
559 | printk(" ops: %lu", class->ops); | |
560 | printk(" {\n"); | |
561 | ||
562 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
563 | if (class->usage_mask & (1 << bit)) { | |
564 | int len = depth; | |
565 | ||
f9829cce | 566 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
567 | len += printk(" at:\n"); |
568 | print_stack_trace(class->usage_traces + bit, len); | |
569 | } | |
570 | } | |
f9829cce | 571 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 572 | |
f9829cce | 573 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
574 | print_ip_sym((unsigned long)class->key); |
575 | } | |
576 | ||
577 | /* | |
578 | * printk all lock dependencies starting at <entry>: | |
579 | */ | |
580 | static void print_lock_dependencies(struct lock_class *class, int depth) | |
581 | { | |
582 | struct lock_list *entry; | |
583 | ||
419ca3f1 DM |
584 | if (lockdep_dependency_visit(class, depth)) |
585 | return; | |
586 | ||
fbb9ce95 IM |
587 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) |
588 | return; | |
589 | ||
590 | print_lock_class_header(class, depth); | |
591 | ||
592 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
593 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
594 | return; | |
595 | ||
fbb9ce95 IM |
596 | print_lock_dependencies(entry->class, depth + 1); |
597 | ||
f9829cce | 598 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
599 | print_stack_trace(&entry->trace, 2); |
600 | printk("\n"); | |
601 | } | |
602 | } | |
603 | ||
8e18257d PZ |
604 | static void print_kernel_version(void) |
605 | { | |
606 | printk("%s %.*s\n", init_utsname()->release, | |
607 | (int)strcspn(init_utsname()->version, " "), | |
608 | init_utsname()->version); | |
609 | } | |
610 | ||
611 | static int very_verbose(struct lock_class *class) | |
612 | { | |
613 | #if VERY_VERBOSE | |
614 | return class_filter(class); | |
615 | #endif | |
616 | return 0; | |
617 | } | |
618 | ||
fbb9ce95 | 619 | /* |
8e18257d | 620 | * Is this the address of a static object: |
fbb9ce95 | 621 | */ |
8e18257d | 622 | static int static_obj(void *obj) |
fbb9ce95 | 623 | { |
8e18257d PZ |
624 | unsigned long start = (unsigned long) &_stext, |
625 | end = (unsigned long) &_end, | |
626 | addr = (unsigned long) obj; | |
627 | #ifdef CONFIG_SMP | |
628 | int i; | |
629 | #endif | |
630 | ||
fbb9ce95 | 631 | /* |
8e18257d | 632 | * static variable? |
fbb9ce95 | 633 | */ |
8e18257d PZ |
634 | if ((addr >= start) && (addr < end)) |
635 | return 1; | |
fbb9ce95 | 636 | |
8e18257d | 637 | #ifdef CONFIG_SMP |
fbb9ce95 | 638 | /* |
8e18257d | 639 | * percpu var? |
fbb9ce95 | 640 | */ |
8e18257d PZ |
641 | for_each_possible_cpu(i) { |
642 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
643 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
644 | + per_cpu_offset(i); | |
fbb9ce95 | 645 | |
8e18257d PZ |
646 | if ((addr >= start) && (addr < end)) |
647 | return 1; | |
648 | } | |
ca58abcb | 649 | #endif |
fbb9ce95 | 650 | |
8e18257d PZ |
651 | /* |
652 | * module var? | |
653 | */ | |
654 | return is_module_address(addr); | |
99de055a DJ |
655 | } |
656 | ||
fbb9ce95 | 657 | /* |
8e18257d PZ |
658 | * To make lock name printouts unique, we calculate a unique |
659 | * class->name_version generation counter: | |
fbb9ce95 | 660 | */ |
8e18257d | 661 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 662 | { |
8e18257d PZ |
663 | struct lock_class *class; |
664 | int count = 0; | |
fbb9ce95 | 665 | |
8e18257d | 666 | if (!new_class->name) |
fbb9ce95 IM |
667 | return 0; |
668 | ||
8e18257d PZ |
669 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
670 | if (new_class->key - new_class->subclass == class->key) | |
671 | return class->name_version; | |
672 | if (class->name && !strcmp(class->name, new_class->name)) | |
673 | count = max(count, class->name_version); | |
674 | } | |
fbb9ce95 | 675 | |
8e18257d | 676 | return count + 1; |
fbb9ce95 IM |
677 | } |
678 | ||
8e18257d PZ |
679 | /* |
680 | * Register a lock's class in the hash-table, if the class is not present | |
681 | * yet. Otherwise we look it up. We cache the result in the lock object | |
682 | * itself, so actual lookup of the hash should be once per lock object. | |
683 | */ | |
684 | static inline struct lock_class * | |
685 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 686 | { |
8e18257d PZ |
687 | struct lockdep_subclass_key *key; |
688 | struct list_head *hash_head; | |
689 | struct lock_class *class; | |
fbb9ce95 | 690 | |
8e18257d PZ |
691 | #ifdef CONFIG_DEBUG_LOCKDEP |
692 | /* | |
693 | * If the architecture calls into lockdep before initializing | |
694 | * the hashes then we'll warn about it later. (we cannot printk | |
695 | * right now) | |
696 | */ | |
697 | if (unlikely(!lockdep_initialized)) { | |
698 | lockdep_init(); | |
699 | lockdep_init_error = 1; | |
c71063c9 | 700 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
701 | } |
702 | #endif | |
fbb9ce95 | 703 | |
8e18257d PZ |
704 | /* |
705 | * Static locks do not have their class-keys yet - for them the key | |
706 | * is the lock object itself: | |
707 | */ | |
708 | if (unlikely(!lock->key)) | |
709 | lock->key = (void *)lock; | |
fbb9ce95 | 710 | |
8e18257d PZ |
711 | /* |
712 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
713 | * lock_class_key variable is passed in through the mutex_init() | |
714 | * (or spin_lock_init()) call - which acts as the key. For static | |
715 | * locks we use the lock object itself as the key. | |
716 | */ | |
4b32d0a4 PZ |
717 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
718 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 719 | |
8e18257d | 720 | key = lock->key->subkeys + subclass; |
ca268c69 | 721 | |
8e18257d | 722 | hash_head = classhashentry(key); |
74c383f1 | 723 | |
8e18257d PZ |
724 | /* |
725 | * We can walk the hash lockfree, because the hash only | |
726 | * grows, and we are careful when adding entries to the end: | |
727 | */ | |
4b32d0a4 PZ |
728 | list_for_each_entry(class, hash_head, hash_entry) { |
729 | if (class->key == key) { | |
730 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 731 | return class; |
4b32d0a4 PZ |
732 | } |
733 | } | |
fbb9ce95 | 734 | |
8e18257d | 735 | return NULL; |
fbb9ce95 IM |
736 | } |
737 | ||
738 | /* | |
8e18257d PZ |
739 | * Register a lock's class in the hash-table, if the class is not present |
740 | * yet. Otherwise we look it up. We cache the result in the lock object | |
741 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 742 | */ |
8e18257d PZ |
743 | static inline struct lock_class * |
744 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 745 | { |
8e18257d PZ |
746 | struct lockdep_subclass_key *key; |
747 | struct list_head *hash_head; | |
748 | struct lock_class *class; | |
749 | unsigned long flags; | |
750 | ||
751 | class = look_up_lock_class(lock, subclass); | |
752 | if (likely(class)) | |
753 | return class; | |
754 | ||
755 | /* | |
756 | * Debug-check: all keys must be persistent! | |
757 | */ | |
758 | if (!static_obj(lock->key)) { | |
759 | debug_locks_off(); | |
760 | printk("INFO: trying to register non-static key.\n"); | |
761 | printk("the code is fine but needs lockdep annotation.\n"); | |
762 | printk("turning off the locking correctness validator.\n"); | |
763 | dump_stack(); | |
764 | ||
765 | return NULL; | |
766 | } | |
767 | ||
768 | key = lock->key->subkeys + subclass; | |
769 | hash_head = classhashentry(key); | |
770 | ||
771 | raw_local_irq_save(flags); | |
772 | if (!graph_lock()) { | |
773 | raw_local_irq_restore(flags); | |
774 | return NULL; | |
775 | } | |
776 | /* | |
777 | * We have to do the hash-walk again, to avoid races | |
778 | * with another CPU: | |
779 | */ | |
780 | list_for_each_entry(class, hash_head, hash_entry) | |
781 | if (class->key == key) | |
782 | goto out_unlock_set; | |
783 | /* | |
784 | * Allocate a new key from the static array, and add it to | |
785 | * the hash: | |
786 | */ | |
787 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
788 | if (!debug_locks_off_graph_unlock()) { | |
789 | raw_local_irq_restore(flags); | |
790 | return NULL; | |
791 | } | |
792 | raw_local_irq_restore(flags); | |
793 | ||
794 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
795 | printk("turning off the locking correctness validator.\n"); | |
796 | return NULL; | |
797 | } | |
798 | class = lock_classes + nr_lock_classes++; | |
799 | debug_atomic_inc(&nr_unused_locks); | |
800 | class->key = key; | |
801 | class->name = lock->name; | |
802 | class->subclass = subclass; | |
803 | INIT_LIST_HEAD(&class->lock_entry); | |
804 | INIT_LIST_HEAD(&class->locks_before); | |
805 | INIT_LIST_HEAD(&class->locks_after); | |
806 | class->name_version = count_matching_names(class); | |
807 | /* | |
808 | * We use RCU's safe list-add method to make | |
809 | * parallel walking of the hash-list safe: | |
810 | */ | |
811 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
812 | /* |
813 | * Add it to the global list of classes: | |
814 | */ | |
815 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
816 | |
817 | if (verbose(class)) { | |
818 | graph_unlock(); | |
819 | raw_local_irq_restore(flags); | |
820 | ||
821 | printk("\nnew class %p: %s", class->key, class->name); | |
822 | if (class->name_version > 1) | |
823 | printk("#%d", class->name_version); | |
824 | printk("\n"); | |
825 | dump_stack(); | |
826 | ||
827 | raw_local_irq_save(flags); | |
828 | if (!graph_lock()) { | |
829 | raw_local_irq_restore(flags); | |
830 | return NULL; | |
831 | } | |
832 | } | |
833 | out_unlock_set: | |
834 | graph_unlock(); | |
835 | raw_local_irq_restore(flags); | |
836 | ||
837 | if (!subclass || force) | |
838 | lock->class_cache = class; | |
839 | ||
840 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
841 | return NULL; | |
842 | ||
843 | return class; | |
844 | } | |
845 | ||
846 | #ifdef CONFIG_PROVE_LOCKING | |
847 | /* | |
848 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
849 | * with NULL on failure) | |
850 | */ | |
851 | static struct lock_list *alloc_list_entry(void) | |
852 | { | |
853 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
854 | if (!debug_locks_off_graph_unlock()) | |
855 | return NULL; | |
856 | ||
857 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
858 | printk("turning off the locking correctness validator.\n"); | |
859 | return NULL; | |
860 | } | |
861 | return list_entries + nr_list_entries++; | |
862 | } | |
863 | ||
864 | /* | |
865 | * Add a new dependency to the head of the list: | |
866 | */ | |
867 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
868 | struct list_head *head, unsigned long ip, int distance) | |
869 | { | |
870 | struct lock_list *entry; | |
871 | /* | |
872 | * Lock not present yet - get a new dependency struct and | |
873 | * add it to the list: | |
874 | */ | |
875 | entry = alloc_list_entry(); | |
876 | if (!entry) | |
877 | return 0; | |
878 | ||
8e18257d PZ |
879 | if (!save_trace(&entry->trace)) |
880 | return 0; | |
881 | ||
74870172 ZY |
882 | entry->class = this; |
883 | entry->distance = distance; | |
8e18257d PZ |
884 | /* |
885 | * Since we never remove from the dependency list, the list can | |
886 | * be walked lockless by other CPUs, it's only allocation | |
887 | * that must be protected by the spinlock. But this also means | |
888 | * we must make new entries visible only once writes to the | |
889 | * entry become visible - hence the RCU op: | |
890 | */ | |
891 | list_add_tail_rcu(&entry->entry, head); | |
892 | ||
893 | return 1; | |
894 | } | |
895 | ||
896 | /* | |
897 | * Recursive, forwards-direction lock-dependency checking, used for | |
898 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
899 | * checking. | |
900 | * | |
901 | * (to keep the stackframe of the recursive functions small we | |
902 | * use these global variables, and we also mark various helper | |
903 | * functions as noinline.) | |
904 | */ | |
905 | static struct held_lock *check_source, *check_target; | |
906 | ||
907 | /* | |
908 | * Print a dependency chain entry (this is only done when a deadlock | |
909 | * has been detected): | |
910 | */ | |
911 | static noinline int | |
912 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |
913 | { | |
914 | if (debug_locks_silent) | |
915 | return 0; | |
916 | printk("\n-> #%u", depth); | |
917 | print_lock_name(target->class); | |
918 | printk(":\n"); | |
919 | print_stack_trace(&target->trace, 6); | |
920 | ||
921 | return 0; | |
922 | } | |
923 | ||
924 | /* | |
925 | * When a circular dependency is detected, print the | |
926 | * header first: | |
927 | */ | |
928 | static noinline int | |
929 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) | |
930 | { | |
931 | struct task_struct *curr = current; | |
932 | ||
933 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
934 | return 0; | |
935 | ||
936 | printk("\n=======================================================\n"); | |
937 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
938 | print_kernel_version(); | |
939 | printk( "-------------------------------------------------------\n"); | |
940 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 941 | curr->comm, task_pid_nr(curr)); |
8e18257d PZ |
942 | print_lock(check_source); |
943 | printk("\nbut task is already holding lock:\n"); | |
944 | print_lock(check_target); | |
945 | printk("\nwhich lock already depends on the new lock.\n\n"); | |
946 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
947 | ||
948 | print_circular_bug_entry(entry, depth); | |
949 | ||
950 | return 0; | |
951 | } | |
952 | ||
953 | static noinline int print_circular_bug_tail(void) | |
954 | { | |
955 | struct task_struct *curr = current; | |
956 | struct lock_list this; | |
957 | ||
958 | if (debug_locks_silent) | |
959 | return 0; | |
960 | ||
f82b217e | 961 | this.class = hlock_class(check_source); |
8e18257d PZ |
962 | if (!save_trace(&this.trace)) |
963 | return 0; | |
964 | ||
965 | print_circular_bug_entry(&this, 0); | |
966 | ||
967 | printk("\nother info that might help us debug this:\n\n"); | |
968 | lockdep_print_held_locks(curr); | |
969 | ||
970 | printk("\nstack backtrace:\n"); | |
971 | dump_stack(); | |
972 | ||
973 | return 0; | |
974 | } | |
975 | ||
976 | #define RECURSION_LIMIT 40 | |
977 | ||
978 | static int noinline print_infinite_recursion_bug(void) | |
979 | { | |
980 | if (!debug_locks_off_graph_unlock()) | |
981 | return 0; | |
982 | ||
983 | WARN_ON(1); | |
984 | ||
985 | return 0; | |
986 | } | |
987 | ||
419ca3f1 DM |
988 | unsigned long __lockdep_count_forward_deps(struct lock_class *class, |
989 | unsigned int depth) | |
990 | { | |
991 | struct lock_list *entry; | |
992 | unsigned long ret = 1; | |
993 | ||
994 | if (lockdep_dependency_visit(class, depth)) | |
995 | return 0; | |
996 | ||
997 | /* | |
998 | * Recurse this class's dependency list: | |
999 | */ | |
1000 | list_for_each_entry(entry, &class->locks_after, entry) | |
1001 | ret += __lockdep_count_forward_deps(entry->class, depth + 1); | |
1002 | ||
1003 | return ret; | |
1004 | } | |
1005 | ||
1006 | unsigned long lockdep_count_forward_deps(struct lock_class *class) | |
1007 | { | |
1008 | unsigned long ret, flags; | |
1009 | ||
1010 | local_irq_save(flags); | |
1011 | __raw_spin_lock(&lockdep_lock); | |
1012 | ret = __lockdep_count_forward_deps(class, 0); | |
1013 | __raw_spin_unlock(&lockdep_lock); | |
1014 | local_irq_restore(flags); | |
1015 | ||
1016 | return ret; | |
1017 | } | |
1018 | ||
1019 | unsigned long __lockdep_count_backward_deps(struct lock_class *class, | |
1020 | unsigned int depth) | |
1021 | { | |
1022 | struct lock_list *entry; | |
1023 | unsigned long ret = 1; | |
1024 | ||
1025 | if (lockdep_dependency_visit(class, depth)) | |
1026 | return 0; | |
1027 | /* | |
1028 | * Recurse this class's dependency list: | |
1029 | */ | |
1030 | list_for_each_entry(entry, &class->locks_before, entry) | |
1031 | ret += __lockdep_count_backward_deps(entry->class, depth + 1); | |
1032 | ||
1033 | return ret; | |
1034 | } | |
1035 | ||
1036 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1037 | { | |
1038 | unsigned long ret, flags; | |
1039 | ||
1040 | local_irq_save(flags); | |
1041 | __raw_spin_lock(&lockdep_lock); | |
1042 | ret = __lockdep_count_backward_deps(class, 0); | |
1043 | __raw_spin_unlock(&lockdep_lock); | |
1044 | local_irq_restore(flags); | |
1045 | ||
1046 | return ret; | |
1047 | } | |
1048 | ||
8e18257d PZ |
1049 | /* |
1050 | * Prove that the dependency graph starting at <entry> can not | |
1051 | * lead to <target>. Print an error and return 0 if it does. | |
1052 | */ | |
1053 | static noinline int | |
1054 | check_noncircular(struct lock_class *source, unsigned int depth) | |
1055 | { | |
1056 | struct lock_list *entry; | |
1057 | ||
419ca3f1 DM |
1058 | if (lockdep_dependency_visit(source, depth)) |
1059 | return 1; | |
1060 | ||
8e18257d PZ |
1061 | debug_atomic_inc(&nr_cyclic_check_recursions); |
1062 | if (depth > max_recursion_depth) | |
fbb9ce95 | 1063 | max_recursion_depth = depth; |
ca268c69 | 1064 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1065 | return print_infinite_recursion_bug(); |
1066 | /* | |
1067 | * Check this lock's dependency list: | |
1068 | */ | |
1069 | list_for_each_entry(entry, &source->locks_after, entry) { | |
f82b217e | 1070 | if (entry->class == hlock_class(check_target)) |
fbb9ce95 IM |
1071 | return print_circular_bug_header(entry, depth+1); |
1072 | debug_atomic_inc(&nr_cyclic_checks); | |
1073 | if (!check_noncircular(entry->class, depth+1)) | |
1074 | return print_circular_bug_entry(entry, depth+1); | |
1075 | } | |
1076 | return 1; | |
1077 | } | |
1078 | ||
81d68a96 | 1079 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1080 | /* |
1081 | * Forwards and backwards subgraph searching, for the purposes of | |
1082 | * proving that two subgraphs can be connected by a new dependency | |
1083 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1084 | */ | |
1085 | static enum lock_usage_bit find_usage_bit; | |
1086 | static struct lock_class *forwards_match, *backwards_match; | |
1087 | ||
1088 | /* | |
1089 | * Find a node in the forwards-direction dependency sub-graph starting | |
1090 | * at <source> that matches <find_usage_bit>. | |
1091 | * | |
1092 | * Return 2 if such a node exists in the subgraph, and put that node | |
1093 | * into <forwards_match>. | |
1094 | * | |
1095 | * Return 1 otherwise and keep <forwards_match> unchanged. | |
1096 | * Return 0 on error. | |
1097 | */ | |
1098 | static noinline int | |
1099 | find_usage_forwards(struct lock_class *source, unsigned int depth) | |
1100 | { | |
1101 | struct lock_list *entry; | |
1102 | int ret; | |
1103 | ||
419ca3f1 DM |
1104 | if (lockdep_dependency_visit(source, depth)) |
1105 | return 1; | |
1106 | ||
fbb9ce95 IM |
1107 | if (depth > max_recursion_depth) |
1108 | max_recursion_depth = depth; | |
ca268c69 | 1109 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1110 | return print_infinite_recursion_bug(); |
1111 | ||
1112 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
1113 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1114 | forwards_match = source; | |
1115 | return 2; | |
1116 | } | |
1117 | ||
1118 | /* | |
1119 | * Check this lock's dependency list: | |
1120 | */ | |
1121 | list_for_each_entry(entry, &source->locks_after, entry) { | |
1122 | debug_atomic_inc(&nr_find_usage_forwards_recursions); | |
1123 | ret = find_usage_forwards(entry->class, depth+1); | |
1124 | if (ret == 2 || ret == 0) | |
1125 | return ret; | |
1126 | } | |
1127 | return 1; | |
1128 | } | |
1129 | ||
1130 | /* | |
1131 | * Find a node in the backwards-direction dependency sub-graph starting | |
1132 | * at <source> that matches <find_usage_bit>. | |
1133 | * | |
1134 | * Return 2 if such a node exists in the subgraph, and put that node | |
1135 | * into <backwards_match>. | |
1136 | * | |
1137 | * Return 1 otherwise and keep <backwards_match> unchanged. | |
1138 | * Return 0 on error. | |
1139 | */ | |
1d09daa5 | 1140 | static noinline int |
fbb9ce95 IM |
1141 | find_usage_backwards(struct lock_class *source, unsigned int depth) |
1142 | { | |
1143 | struct lock_list *entry; | |
1144 | int ret; | |
1145 | ||
419ca3f1 DM |
1146 | if (lockdep_dependency_visit(source, depth)) |
1147 | return 1; | |
1148 | ||
381a2292 JP |
1149 | if (!__raw_spin_is_locked(&lockdep_lock)) |
1150 | return DEBUG_LOCKS_WARN_ON(1); | |
1151 | ||
fbb9ce95 IM |
1152 | if (depth > max_recursion_depth) |
1153 | max_recursion_depth = depth; | |
ca268c69 | 1154 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1155 | return print_infinite_recursion_bug(); |
1156 | ||
1157 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
1158 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1159 | backwards_match = source; | |
1160 | return 2; | |
1161 | } | |
1162 | ||
f82b217e DJ |
1163 | if (!source && debug_locks_off_graph_unlock()) { |
1164 | WARN_ON(1); | |
1165 | return 0; | |
1166 | } | |
1167 | ||
fbb9ce95 IM |
1168 | /* |
1169 | * Check this lock's dependency list: | |
1170 | */ | |
1171 | list_for_each_entry(entry, &source->locks_before, entry) { | |
1172 | debug_atomic_inc(&nr_find_usage_backwards_recursions); | |
1173 | ret = find_usage_backwards(entry->class, depth+1); | |
1174 | if (ret == 2 || ret == 0) | |
1175 | return ret; | |
1176 | } | |
1177 | return 1; | |
1178 | } | |
1179 | ||
1180 | static int | |
1181 | print_bad_irq_dependency(struct task_struct *curr, | |
1182 | struct held_lock *prev, | |
1183 | struct held_lock *next, | |
1184 | enum lock_usage_bit bit1, | |
1185 | enum lock_usage_bit bit2, | |
1186 | const char *irqclass) | |
1187 | { | |
74c383f1 | 1188 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1189 | return 0; |
1190 | ||
1191 | printk("\n======================================================\n"); | |
1192 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1193 | irqclass, irqclass); | |
99de055a | 1194 | print_kernel_version(); |
fbb9ce95 IM |
1195 | printk( "------------------------------------------------------\n"); |
1196 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1197 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1198 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1199 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1200 | curr->hardirqs_enabled, | |
1201 | curr->softirqs_enabled); | |
1202 | print_lock(next); | |
1203 | ||
1204 | printk("\nand this task is already holding:\n"); | |
1205 | print_lock(prev); | |
1206 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1207 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1208 | printk(" ->"); |
f82b217e | 1209 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1210 | printk("\n"); |
1211 | ||
1212 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1213 | irqclass); | |
1214 | print_lock_name(backwards_match); | |
1215 | printk("\n... which became %s-irq-safe at:\n", irqclass); | |
1216 | ||
1217 | print_stack_trace(backwards_match->usage_traces + bit1, 1); | |
1218 | ||
1219 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
1220 | print_lock_name(forwards_match); | |
1221 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); | |
1222 | printk("..."); | |
1223 | ||
1224 | print_stack_trace(forwards_match->usage_traces + bit2, 1); | |
1225 | ||
1226 | printk("\nother info that might help us debug this:\n\n"); | |
1227 | lockdep_print_held_locks(curr); | |
1228 | ||
1229 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); | |
1230 | print_lock_dependencies(backwards_match, 0); | |
1231 | ||
1232 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); | |
1233 | print_lock_dependencies(forwards_match, 0); | |
1234 | ||
1235 | printk("\nstack backtrace:\n"); | |
1236 | dump_stack(); | |
1237 | ||
1238 | return 0; | |
1239 | } | |
1240 | ||
1241 | static int | |
1242 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1243 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1244 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1245 | { | |
1246 | int ret; | |
1247 | ||
1248 | find_usage_bit = bit_backwards; | |
1249 | /* fills in <backwards_match> */ | |
f82b217e | 1250 | ret = find_usage_backwards(hlock_class(prev), 0); |
fbb9ce95 IM |
1251 | if (!ret || ret == 1) |
1252 | return ret; | |
1253 | ||
1254 | find_usage_bit = bit_forwards; | |
f82b217e | 1255 | ret = find_usage_forwards(hlock_class(next), 0); |
fbb9ce95 IM |
1256 | if (!ret || ret == 1) |
1257 | return ret; | |
1258 | /* ret == 2 */ | |
1259 | return print_bad_irq_dependency(curr, prev, next, | |
1260 | bit_backwards, bit_forwards, irqclass); | |
1261 | } | |
1262 | ||
8e18257d PZ |
1263 | static int |
1264 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1265 | struct held_lock *next) | |
1266 | { | |
1267 | /* | |
1268 | * Prove that the new dependency does not connect a hardirq-safe | |
1269 | * lock with a hardirq-unsafe lock - to achieve this we search | |
1270 | * the backwards-subgraph starting at <prev>, and the | |
1271 | * forwards-subgraph starting at <next>: | |
1272 | */ | |
1273 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, | |
1274 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1275 | return 0; | |
1276 | ||
1277 | /* | |
1278 | * Prove that the new dependency does not connect a hardirq-safe-read | |
1279 | * lock with a hardirq-unsafe lock - to achieve this we search | |
1280 | * the backwards-subgraph starting at <prev>, and the | |
1281 | * forwards-subgraph starting at <next>: | |
1282 | */ | |
1283 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, | |
1284 | LOCK_ENABLED_HARDIRQS, "hard-read")) | |
1285 | return 0; | |
1286 | ||
1287 | /* | |
1288 | * Prove that the new dependency does not connect a softirq-safe | |
1289 | * lock with a softirq-unsafe lock - to achieve this we search | |
1290 | * the backwards-subgraph starting at <prev>, and the | |
1291 | * forwards-subgraph starting at <next>: | |
1292 | */ | |
1293 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, | |
1294 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1295 | return 0; | |
1296 | /* | |
1297 | * Prove that the new dependency does not connect a softirq-safe-read | |
1298 | * lock with a softirq-unsafe lock - to achieve this we search | |
1299 | * the backwards-subgraph starting at <prev>, and the | |
1300 | * forwards-subgraph starting at <next>: | |
1301 | */ | |
1302 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, | |
1303 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1304 | return 0; | |
1305 | ||
1306 | return 1; | |
1307 | } | |
1308 | ||
1309 | static void inc_chains(void) | |
1310 | { | |
1311 | if (current->hardirq_context) | |
1312 | nr_hardirq_chains++; | |
1313 | else { | |
1314 | if (current->softirq_context) | |
1315 | nr_softirq_chains++; | |
1316 | else | |
1317 | nr_process_chains++; | |
1318 | } | |
1319 | } | |
1320 | ||
1321 | #else | |
1322 | ||
1323 | static inline int | |
1324 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1325 | struct held_lock *next) | |
1326 | { | |
1327 | return 1; | |
1328 | } | |
1329 | ||
1330 | static inline void inc_chains(void) | |
1331 | { | |
1332 | nr_process_chains++; | |
1333 | } | |
1334 | ||
fbb9ce95 IM |
1335 | #endif |
1336 | ||
1337 | static int | |
1338 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1339 | struct held_lock *next) | |
1340 | { | |
74c383f1 | 1341 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1342 | return 0; |
1343 | ||
1344 | printk("\n=============================================\n"); | |
1345 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1346 | print_kernel_version(); |
fbb9ce95 IM |
1347 | printk( "---------------------------------------------\n"); |
1348 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1349 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1350 | print_lock(next); |
1351 | printk("\nbut task is already holding lock:\n"); | |
1352 | print_lock(prev); | |
1353 | ||
1354 | printk("\nother info that might help us debug this:\n"); | |
1355 | lockdep_print_held_locks(curr); | |
1356 | ||
1357 | printk("\nstack backtrace:\n"); | |
1358 | dump_stack(); | |
1359 | ||
1360 | return 0; | |
1361 | } | |
1362 | ||
1363 | /* | |
1364 | * Check whether we are holding such a class already. | |
1365 | * | |
1366 | * (Note that this has to be done separately, because the graph cannot | |
1367 | * detect such classes of deadlocks.) | |
1368 | * | |
1369 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1370 | */ | |
1371 | static int | |
1372 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1373 | struct lockdep_map *next_instance, int read) | |
1374 | { | |
1375 | struct held_lock *prev; | |
7531e2f3 | 1376 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1377 | int i; |
1378 | ||
1379 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1380 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1381 | |
1382 | if (prev->instance == next->nest_lock) | |
1383 | nest = prev; | |
1384 | ||
f82b217e | 1385 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1386 | continue; |
7531e2f3 | 1387 | |
fbb9ce95 IM |
1388 | /* |
1389 | * Allow read-after-read recursion of the same | |
6c9076ec | 1390 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1391 | */ |
6c9076ec | 1392 | if ((read == 2) && prev->read) |
fbb9ce95 | 1393 | return 2; |
7531e2f3 PZ |
1394 | |
1395 | /* | |
1396 | * We're holding the nest_lock, which serializes this lock's | |
1397 | * nesting behaviour. | |
1398 | */ | |
1399 | if (nest) | |
1400 | return 2; | |
1401 | ||
fbb9ce95 IM |
1402 | return print_deadlock_bug(curr, prev, next); |
1403 | } | |
1404 | return 1; | |
1405 | } | |
1406 | ||
1407 | /* | |
1408 | * There was a chain-cache miss, and we are about to add a new dependency | |
1409 | * to a previous lock. We recursively validate the following rules: | |
1410 | * | |
1411 | * - would the adding of the <prev> -> <next> dependency create a | |
1412 | * circular dependency in the graph? [== circular deadlock] | |
1413 | * | |
1414 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1415 | * (in the full backwards-subgraph starting at <prev>) with any | |
1416 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1417 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1418 | * | |
1419 | * - does the new prev->next dependency connect any softirq-safe lock | |
1420 | * (in the full backwards-subgraph starting at <prev>) with any | |
1421 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1422 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1423 | * | |
1424 | * any of these scenarios could lead to a deadlock. | |
1425 | * | |
1426 | * Then if all the validations pass, we add the forwards and backwards | |
1427 | * dependency. | |
1428 | */ | |
1429 | static int | |
1430 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1431 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1432 | { |
1433 | struct lock_list *entry; | |
1434 | int ret; | |
1435 | ||
1436 | /* | |
1437 | * Prove that the new <prev> -> <next> dependency would not | |
1438 | * create a circular dependency in the graph. (We do this by | |
1439 | * forward-recursing into the graph starting at <next>, and | |
1440 | * checking whether we can reach <prev>.) | |
1441 | * | |
1442 | * We are using global variables to control the recursion, to | |
1443 | * keep the stackframe size of the recursive functions low: | |
1444 | */ | |
1445 | check_source = next; | |
1446 | check_target = prev; | |
f82b217e | 1447 | if (!(check_noncircular(hlock_class(next), 0))) |
fbb9ce95 IM |
1448 | return print_circular_bug_tail(); |
1449 | ||
8e18257d | 1450 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1451 | return 0; |
1452 | ||
fbb9ce95 IM |
1453 | /* |
1454 | * For recursive read-locks we do all the dependency checks, | |
1455 | * but we dont store read-triggered dependencies (only | |
1456 | * write-triggered dependencies). This ensures that only the | |
1457 | * write-side dependencies matter, and that if for example a | |
1458 | * write-lock never takes any other locks, then the reads are | |
1459 | * equivalent to a NOP. | |
1460 | */ | |
1461 | if (next->read == 2 || prev->read == 2) | |
1462 | return 1; | |
1463 | /* | |
1464 | * Is the <prev> -> <next> dependency already present? | |
1465 | * | |
1466 | * (this may occur even though this is a new chain: consider | |
1467 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1468 | * chains - the second one will be new, but L1 already has | |
1469 | * L2 added to its dependency list, due to the first chain.) | |
1470 | */ | |
f82b217e DJ |
1471 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1472 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1473 | if (distance == 1) |
1474 | entry->distance = 1; | |
fbb9ce95 | 1475 | return 2; |
068135e6 | 1476 | } |
fbb9ce95 IM |
1477 | } |
1478 | ||
1479 | /* | |
1480 | * Ok, all validations passed, add the new lock | |
1481 | * to the previous lock's dependency list: | |
1482 | */ | |
f82b217e DJ |
1483 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1484 | &hlock_class(prev)->locks_after, | |
1485 | next->acquire_ip, distance); | |
068135e6 | 1486 | |
fbb9ce95 IM |
1487 | if (!ret) |
1488 | return 0; | |
910b1b2e | 1489 | |
f82b217e DJ |
1490 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1491 | &hlock_class(next)->locks_before, | |
1492 | next->acquire_ip, distance); | |
910b1b2e JP |
1493 | if (!ret) |
1494 | return 0; | |
fbb9ce95 IM |
1495 | |
1496 | /* | |
8e18257d PZ |
1497 | * Debugging printouts: |
1498 | */ | |
f82b217e | 1499 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1500 | graph_unlock(); |
1501 | printk("\n new dependency: "); | |
f82b217e | 1502 | print_lock_name(hlock_class(prev)); |
8e18257d | 1503 | printk(" => "); |
f82b217e | 1504 | print_lock_name(hlock_class(next)); |
8e18257d | 1505 | printk("\n"); |
fbb9ce95 | 1506 | dump_stack(); |
8e18257d | 1507 | return graph_lock(); |
fbb9ce95 | 1508 | } |
8e18257d PZ |
1509 | return 1; |
1510 | } | |
fbb9ce95 | 1511 | |
8e18257d PZ |
1512 | /* |
1513 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1514 | * The ones that are relevant are (in increasing distance from curr): | |
1515 | * all consecutive trylock entries and the final non-trylock entry - or | |
1516 | * the end of this context's lock-chain - whichever comes first. | |
1517 | */ | |
1518 | static int | |
1519 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1520 | { | |
1521 | int depth = curr->lockdep_depth; | |
1522 | struct held_lock *hlock; | |
d6d897ce | 1523 | |
fbb9ce95 | 1524 | /* |
8e18257d PZ |
1525 | * Debugging checks. |
1526 | * | |
1527 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1528 | */ |
8e18257d PZ |
1529 | if (!depth) |
1530 | goto out_bug; | |
fbb9ce95 | 1531 | /* |
8e18257d PZ |
1532 | * At least two relevant locks must exist for this |
1533 | * to be a head: | |
fbb9ce95 | 1534 | */ |
8e18257d PZ |
1535 | if (curr->held_locks[depth].irq_context != |
1536 | curr->held_locks[depth-1].irq_context) | |
1537 | goto out_bug; | |
74c383f1 | 1538 | |
8e18257d PZ |
1539 | for (;;) { |
1540 | int distance = curr->lockdep_depth - depth + 1; | |
1541 | hlock = curr->held_locks + depth-1; | |
1542 | /* | |
1543 | * Only non-recursive-read entries get new dependencies | |
1544 | * added: | |
1545 | */ | |
1546 | if (hlock->read != 2) { | |
1547 | if (!check_prev_add(curr, hlock, next, distance)) | |
1548 | return 0; | |
1549 | /* | |
1550 | * Stop after the first non-trylock entry, | |
1551 | * as non-trylock entries have added their | |
1552 | * own direct dependencies already, so this | |
1553 | * lock is connected to them indirectly: | |
1554 | */ | |
1555 | if (!hlock->trylock) | |
1556 | break; | |
74c383f1 | 1557 | } |
8e18257d PZ |
1558 | depth--; |
1559 | /* | |
1560 | * End of lock-stack? | |
1561 | */ | |
1562 | if (!depth) | |
1563 | break; | |
1564 | /* | |
1565 | * Stop the search if we cross into another context: | |
1566 | */ | |
1567 | if (curr->held_locks[depth].irq_context != | |
1568 | curr->held_locks[depth-1].irq_context) | |
1569 | break; | |
fbb9ce95 | 1570 | } |
8e18257d PZ |
1571 | return 1; |
1572 | out_bug: | |
1573 | if (!debug_locks_off_graph_unlock()) | |
1574 | return 0; | |
fbb9ce95 | 1575 | |
8e18257d | 1576 | WARN_ON(1); |
fbb9ce95 | 1577 | |
8e18257d | 1578 | return 0; |
fbb9ce95 IM |
1579 | } |
1580 | ||
8e18257d | 1581 | unsigned long nr_lock_chains; |
443cd507 | 1582 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1583 | int nr_chain_hlocks; |
443cd507 HY |
1584 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1585 | ||
1586 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1587 | { | |
1588 | return lock_classes + chain_hlocks[chain->base + i]; | |
1589 | } | |
8e18257d | 1590 | |
fbb9ce95 IM |
1591 | /* |
1592 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1593 | * add it and return 1 - in this case the new dependency chain is |
1594 | * validated. If the key is already hashed, return 0. | |
1595 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1596 | */ |
443cd507 HY |
1597 | static inline int lookup_chain_cache(struct task_struct *curr, |
1598 | struct held_lock *hlock, | |
1599 | u64 chain_key) | |
fbb9ce95 | 1600 | { |
f82b217e | 1601 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1602 | struct list_head *hash_head = chainhashentry(chain_key); |
1603 | struct lock_chain *chain; | |
443cd507 | 1604 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1605 | int i, j, n, cn; |
fbb9ce95 | 1606 | |
381a2292 JP |
1607 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1608 | return 0; | |
fbb9ce95 IM |
1609 | /* |
1610 | * We can walk it lock-free, because entries only get added | |
1611 | * to the hash: | |
1612 | */ | |
1613 | list_for_each_entry(chain, hash_head, entry) { | |
1614 | if (chain->chain_key == chain_key) { | |
1615 | cache_hit: | |
1616 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1617 | if (very_verbose(class)) |
755cd900 AM |
1618 | printk("\nhash chain already cached, key: " |
1619 | "%016Lx tail class: [%p] %s\n", | |
1620 | (unsigned long long)chain_key, | |
1621 | class->key, class->name); | |
fbb9ce95 IM |
1622 | return 0; |
1623 | } | |
1624 | } | |
81fc685a | 1625 | if (very_verbose(class)) |
755cd900 AM |
1626 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1627 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1628 | /* |
1629 | * Allocate a new chain entry from the static array, and add | |
1630 | * it to the hash: | |
1631 | */ | |
74c383f1 IM |
1632 | if (!graph_lock()) |
1633 | return 0; | |
fbb9ce95 IM |
1634 | /* |
1635 | * We have to walk the chain again locked - to avoid duplicates: | |
1636 | */ | |
1637 | list_for_each_entry(chain, hash_head, entry) { | |
1638 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1639 | graph_unlock(); |
fbb9ce95 IM |
1640 | goto cache_hit; |
1641 | } | |
1642 | } | |
1643 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1644 | if (!debug_locks_off_graph_unlock()) |
1645 | return 0; | |
1646 | ||
fbb9ce95 IM |
1647 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1648 | printk("turning off the locking correctness validator.\n"); | |
1649 | return 0; | |
1650 | } | |
1651 | chain = lock_chains + nr_lock_chains++; | |
1652 | chain->chain_key = chain_key; | |
443cd507 HY |
1653 | chain->irq_context = hlock->irq_context; |
1654 | /* Find the first held_lock of current chain */ | |
1655 | hlock_next = hlock; | |
1656 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1657 | hlock_curr = curr->held_locks + i; | |
1658 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1659 | break; | |
1660 | hlock_next = hlock; | |
1661 | } | |
1662 | i++; | |
1663 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1664 | cn = nr_chain_hlocks; |
1665 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1666 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1667 | if (n == cn) | |
1668 | break; | |
1669 | cn = n; | |
1670 | } | |
1671 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1672 | chain->base = cn; | |
443cd507 | 1673 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1674 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1675 | chain_hlocks[chain->base + j] = lock_id; |
1676 | } | |
1677 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1678 | } | |
fbb9ce95 IM |
1679 | list_add_tail_rcu(&chain->entry, hash_head); |
1680 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1681 | inc_chains(); |
1682 | ||
1683 | return 1; | |
1684 | } | |
1685 | ||
1686 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1687 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1688 | { |
1689 | /* | |
1690 | * Trylock needs to maintain the stack of held locks, but it | |
1691 | * does not add new dependencies, because trylock can be done | |
1692 | * in any order. | |
1693 | * | |
1694 | * We look up the chain_key and do the O(N^2) check and update of | |
1695 | * the dependencies only if this is a new dependency chain. | |
1696 | * (If lookup_chain_cache() returns with 1 it acquires | |
1697 | * graph_lock for us) | |
1698 | */ | |
1699 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1700 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1701 | /* |
1702 | * Check whether last held lock: | |
1703 | * | |
1704 | * - is irq-safe, if this lock is irq-unsafe | |
1705 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1706 | * | |
1707 | * And check whether the new lock's dependency graph | |
1708 | * could lead back to the previous lock. | |
1709 | * | |
1710 | * any of these scenarios could lead to a deadlock. If | |
1711 | * All validations | |
1712 | */ | |
1713 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1714 | ||
1715 | if (!ret) | |
1716 | return 0; | |
1717 | /* | |
1718 | * Mark recursive read, as we jump over it when | |
1719 | * building dependencies (just like we jump over | |
1720 | * trylock entries): | |
1721 | */ | |
1722 | if (ret == 2) | |
1723 | hlock->read = 2; | |
1724 | /* | |
1725 | * Add dependency only if this lock is not the head | |
1726 | * of the chain, and if it's not a secondary read-lock: | |
1727 | */ | |
1728 | if (!chain_head && ret != 2) | |
1729 | if (!check_prevs_add(curr, hlock)) | |
1730 | return 0; | |
1731 | graph_unlock(); | |
1732 | } else | |
1733 | /* after lookup_chain_cache(): */ | |
1734 | if (unlikely(!debug_locks)) | |
1735 | return 0; | |
fbb9ce95 IM |
1736 | |
1737 | return 1; | |
1738 | } | |
8e18257d PZ |
1739 | #else |
1740 | static inline int validate_chain(struct task_struct *curr, | |
1741 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1742 | int chain_head, u64 chain_key) |
8e18257d PZ |
1743 | { |
1744 | return 1; | |
1745 | } | |
ca58abcb | 1746 | #endif |
fbb9ce95 IM |
1747 | |
1748 | /* | |
1749 | * We are building curr_chain_key incrementally, so double-check | |
1750 | * it from scratch, to make sure that it's done correctly: | |
1751 | */ | |
1d09daa5 | 1752 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1753 | { |
1754 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1755 | struct held_lock *hlock, *prev_hlock = NULL; | |
1756 | unsigned int i, id; | |
1757 | u64 chain_key = 0; | |
1758 | ||
1759 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1760 | hlock = curr->held_locks + i; | |
1761 | if (chain_key != hlock->prev_chain_key) { | |
1762 | debug_locks_off(); | |
2df8b1d6 | 1763 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1764 | curr->lockdep_depth, i, |
1765 | (unsigned long long)chain_key, | |
1766 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1767 | return; |
1768 | } | |
f82b217e | 1769 | id = hlock->class_idx - 1; |
381a2292 JP |
1770 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1771 | return; | |
1772 | ||
fbb9ce95 IM |
1773 | if (prev_hlock && (prev_hlock->irq_context != |
1774 | hlock->irq_context)) | |
1775 | chain_key = 0; | |
1776 | chain_key = iterate_chain_key(chain_key, id); | |
1777 | prev_hlock = hlock; | |
1778 | } | |
1779 | if (chain_key != curr->curr_chain_key) { | |
1780 | debug_locks_off(); | |
2df8b1d6 | 1781 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1782 | curr->lockdep_depth, i, |
1783 | (unsigned long long)chain_key, | |
1784 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1785 | } |
1786 | #endif | |
1787 | } | |
1788 | ||
8e18257d PZ |
1789 | static int |
1790 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1791 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1792 | { | |
1793 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1794 | return 0; | |
1795 | ||
1796 | printk("\n=================================\n"); | |
1797 | printk( "[ INFO: inconsistent lock state ]\n"); | |
1798 | print_kernel_version(); | |
1799 | printk( "---------------------------------\n"); | |
1800 | ||
1801 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1802 | usage_str[prev_bit], usage_str[new_bit]); | |
1803 | ||
1804 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 1805 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
1806 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
1807 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1808 | trace_hardirqs_enabled(curr), | |
1809 | trace_softirqs_enabled(curr)); | |
1810 | print_lock(this); | |
1811 | ||
1812 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 1813 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
1814 | |
1815 | print_irqtrace_events(curr); | |
1816 | printk("\nother info that might help us debug this:\n"); | |
1817 | lockdep_print_held_locks(curr); | |
1818 | ||
1819 | printk("\nstack backtrace:\n"); | |
1820 | dump_stack(); | |
1821 | ||
1822 | return 0; | |
1823 | } | |
1824 | ||
1825 | /* | |
1826 | * Print out an error if an invalid bit is set: | |
1827 | */ | |
1828 | static inline int | |
1829 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1830 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1831 | { | |
f82b217e | 1832 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
1833 | return print_usage_bug(curr, this, bad_bit, new_bit); |
1834 | return 1; | |
1835 | } | |
1836 | ||
1837 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
1838 | enum lock_usage_bit new_bit); | |
1839 | ||
81d68a96 | 1840 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1841 | |
1842 | /* | |
1843 | * print irq inversion bug: | |
1844 | */ | |
1845 | static int | |
1846 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, | |
1847 | struct held_lock *this, int forwards, | |
1848 | const char *irqclass) | |
1849 | { | |
74c383f1 | 1850 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1851 | return 0; |
1852 | ||
1853 | printk("\n=========================================================\n"); | |
1854 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 1855 | print_kernel_version(); |
fbb9ce95 IM |
1856 | printk( "---------------------------------------------------------\n"); |
1857 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 1858 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1859 | print_lock(this); |
1860 | if (forwards) | |
1861 | printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass); | |
1862 | else | |
1863 | printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass); | |
1864 | print_lock_name(other); | |
1865 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); | |
1866 | ||
1867 | printk("\nother info that might help us debug this:\n"); | |
1868 | lockdep_print_held_locks(curr); | |
1869 | ||
1870 | printk("\nthe first lock's dependencies:\n"); | |
f82b217e | 1871 | print_lock_dependencies(hlock_class(this), 0); |
fbb9ce95 IM |
1872 | |
1873 | printk("\nthe second lock's dependencies:\n"); | |
1874 | print_lock_dependencies(other, 0); | |
1875 | ||
1876 | printk("\nstack backtrace:\n"); | |
1877 | dump_stack(); | |
1878 | ||
1879 | return 0; | |
1880 | } | |
1881 | ||
1882 | /* | |
1883 | * Prove that in the forwards-direction subgraph starting at <this> | |
1884 | * there is no lock matching <mask>: | |
1885 | */ | |
1886 | static int | |
1887 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
1888 | enum lock_usage_bit bit, const char *irqclass) | |
1889 | { | |
1890 | int ret; | |
1891 | ||
1892 | find_usage_bit = bit; | |
1893 | /* fills in <forwards_match> */ | |
f82b217e | 1894 | ret = find_usage_forwards(hlock_class(this), 0); |
fbb9ce95 IM |
1895 | if (!ret || ret == 1) |
1896 | return ret; | |
1897 | ||
1898 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); | |
1899 | } | |
1900 | ||
1901 | /* | |
1902 | * Prove that in the backwards-direction subgraph starting at <this> | |
1903 | * there is no lock matching <mask>: | |
1904 | */ | |
1905 | static int | |
1906 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
1907 | enum lock_usage_bit bit, const char *irqclass) | |
1908 | { | |
1909 | int ret; | |
1910 | ||
1911 | find_usage_bit = bit; | |
1912 | /* fills in <backwards_match> */ | |
f82b217e | 1913 | ret = find_usage_backwards(hlock_class(this), 0); |
fbb9ce95 IM |
1914 | if (!ret || ret == 1) |
1915 | return ret; | |
1916 | ||
1917 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); | |
1918 | } | |
1919 | ||
3117df04 | 1920 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
1921 | { |
1922 | printk("irq event stamp: %u\n", curr->irq_events); | |
1923 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
1924 | print_ip_sym(curr->hardirq_enable_ip); | |
1925 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
1926 | print_ip_sym(curr->hardirq_disable_ip); | |
1927 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
1928 | print_ip_sym(curr->softirq_enable_ip); | |
1929 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
1930 | print_ip_sym(curr->softirq_disable_ip); | |
1931 | } | |
1932 | ||
8e18257d | 1933 | static int hardirq_verbose(struct lock_class *class) |
fbb9ce95 | 1934 | { |
8e18257d PZ |
1935 | #if HARDIRQ_VERBOSE |
1936 | return class_filter(class); | |
1937 | #endif | |
fbb9ce95 IM |
1938 | return 0; |
1939 | } | |
1940 | ||
8e18257d | 1941 | static int softirq_verbose(struct lock_class *class) |
fbb9ce95 | 1942 | { |
8e18257d PZ |
1943 | #if SOFTIRQ_VERBOSE |
1944 | return class_filter(class); | |
1945 | #endif | |
1946 | return 0; | |
fbb9ce95 IM |
1947 | } |
1948 | ||
1949 | #define STRICT_READ_CHECKS 1 | |
1950 | ||
8e18257d PZ |
1951 | static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
1952 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 1953 | { |
8e18257d | 1954 | int ret = 1; |
fbb9ce95 | 1955 | |
8e18257d | 1956 | switch(new_bit) { |
fbb9ce95 IM |
1957 | case LOCK_USED_IN_HARDIRQ: |
1958 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1959 | return 0; | |
1960 | if (!valid_state(curr, this, new_bit, | |
1961 | LOCK_ENABLED_HARDIRQS_READ)) | |
1962 | return 0; | |
1963 | /* | |
1964 | * just marked it hardirq-safe, check that this lock | |
1965 | * took no hardirq-unsafe lock in the past: | |
1966 | */ | |
1967 | if (!check_usage_forwards(curr, this, | |
1968 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1969 | return 0; | |
1970 | #if STRICT_READ_CHECKS | |
1971 | /* | |
1972 | * just marked it hardirq-safe, check that this lock | |
1973 | * took no hardirq-unsafe-read lock in the past: | |
1974 | */ | |
1975 | if (!check_usage_forwards(curr, this, | |
1976 | LOCK_ENABLED_HARDIRQS_READ, "hard-read")) | |
1977 | return 0; | |
1978 | #endif | |
f82b217e | 1979 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
1980 | ret = 2; |
1981 | break; | |
1982 | case LOCK_USED_IN_SOFTIRQ: | |
1983 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1984 | return 0; | |
1985 | if (!valid_state(curr, this, new_bit, | |
1986 | LOCK_ENABLED_SOFTIRQS_READ)) | |
1987 | return 0; | |
1988 | /* | |
1989 | * just marked it softirq-safe, check that this lock | |
1990 | * took no softirq-unsafe lock in the past: | |
1991 | */ | |
1992 | if (!check_usage_forwards(curr, this, | |
1993 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1994 | return 0; | |
1995 | #if STRICT_READ_CHECKS | |
1996 | /* | |
1997 | * just marked it softirq-safe, check that this lock | |
1998 | * took no softirq-unsafe-read lock in the past: | |
1999 | */ | |
2000 | if (!check_usage_forwards(curr, this, | |
2001 | LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) | |
2002 | return 0; | |
2003 | #endif | |
f82b217e | 2004 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2005 | ret = 2; |
2006 | break; | |
2007 | case LOCK_USED_IN_HARDIRQ_READ: | |
2008 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
2009 | return 0; | |
2010 | /* | |
2011 | * just marked it hardirq-read-safe, check that this lock | |
2012 | * took no hardirq-unsafe lock in the past: | |
2013 | */ | |
2014 | if (!check_usage_forwards(curr, this, | |
2015 | LOCK_ENABLED_HARDIRQS, "hard")) | |
2016 | return 0; | |
f82b217e | 2017 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2018 | ret = 2; |
2019 | break; | |
2020 | case LOCK_USED_IN_SOFTIRQ_READ: | |
2021 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
2022 | return 0; | |
2023 | /* | |
2024 | * just marked it softirq-read-safe, check that this lock | |
2025 | * took no softirq-unsafe lock in the past: | |
2026 | */ | |
2027 | if (!check_usage_forwards(curr, this, | |
2028 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
2029 | return 0; | |
f82b217e | 2030 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2031 | ret = 2; |
2032 | break; | |
2033 | case LOCK_ENABLED_HARDIRQS: | |
2034 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
2035 | return 0; | |
2036 | if (!valid_state(curr, this, new_bit, | |
2037 | LOCK_USED_IN_HARDIRQ_READ)) | |
2038 | return 0; | |
2039 | /* | |
2040 | * just marked it hardirq-unsafe, check that no hardirq-safe | |
2041 | * lock in the system ever took it in the past: | |
2042 | */ | |
2043 | if (!check_usage_backwards(curr, this, | |
2044 | LOCK_USED_IN_HARDIRQ, "hard")) | |
2045 | return 0; | |
2046 | #if STRICT_READ_CHECKS | |
2047 | /* | |
2048 | * just marked it hardirq-unsafe, check that no | |
2049 | * hardirq-safe-read lock in the system ever took | |
2050 | * it in the past: | |
2051 | */ | |
2052 | if (!check_usage_backwards(curr, this, | |
2053 | LOCK_USED_IN_HARDIRQ_READ, "hard-read")) | |
2054 | return 0; | |
2055 | #endif | |
f82b217e | 2056 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2057 | ret = 2; |
2058 | break; | |
2059 | case LOCK_ENABLED_SOFTIRQS: | |
2060 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
2061 | return 0; | |
2062 | if (!valid_state(curr, this, new_bit, | |
2063 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2064 | return 0; | |
2065 | /* | |
2066 | * just marked it softirq-unsafe, check that no softirq-safe | |
2067 | * lock in the system ever took it in the past: | |
2068 | */ | |
2069 | if (!check_usage_backwards(curr, this, | |
2070 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
2071 | return 0; | |
2072 | #if STRICT_READ_CHECKS | |
2073 | /* | |
2074 | * just marked it softirq-unsafe, check that no | |
2075 | * softirq-safe-read lock in the system ever took | |
2076 | * it in the past: | |
2077 | */ | |
2078 | if (!check_usage_backwards(curr, this, | |
2079 | LOCK_USED_IN_SOFTIRQ_READ, "soft-read")) | |
2080 | return 0; | |
2081 | #endif | |
f82b217e | 2082 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2083 | ret = 2; |
2084 | break; | |
2085 | case LOCK_ENABLED_HARDIRQS_READ: | |
2086 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
2087 | return 0; | |
2088 | #if STRICT_READ_CHECKS | |
2089 | /* | |
2090 | * just marked it hardirq-read-unsafe, check that no | |
2091 | * hardirq-safe lock in the system ever took it in the past: | |
2092 | */ | |
2093 | if (!check_usage_backwards(curr, this, | |
2094 | LOCK_USED_IN_HARDIRQ, "hard")) | |
2095 | return 0; | |
2096 | #endif | |
f82b217e | 2097 | if (hardirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2098 | ret = 2; |
2099 | break; | |
2100 | case LOCK_ENABLED_SOFTIRQS_READ: | |
2101 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
2102 | return 0; | |
2103 | #if STRICT_READ_CHECKS | |
2104 | /* | |
2105 | * just marked it softirq-read-unsafe, check that no | |
2106 | * softirq-safe lock in the system ever took it in the past: | |
2107 | */ | |
2108 | if (!check_usage_backwards(curr, this, | |
2109 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
2110 | return 0; | |
2111 | #endif | |
f82b217e | 2112 | if (softirq_verbose(hlock_class(this))) |
fbb9ce95 IM |
2113 | ret = 2; |
2114 | break; | |
fbb9ce95 | 2115 | default: |
fbb9ce95 | 2116 | WARN_ON(1); |
8e18257d | 2117 | break; |
fbb9ce95 IM |
2118 | } |
2119 | ||
2120 | return ret; | |
2121 | } | |
2122 | ||
fbb9ce95 IM |
2123 | /* |
2124 | * Mark all held locks with a usage bit: | |
2125 | */ | |
1d09daa5 | 2126 | static int |
4ff773bb | 2127 | mark_held_locks(struct task_struct *curr, int hardirq) |
fbb9ce95 IM |
2128 | { |
2129 | enum lock_usage_bit usage_bit; | |
2130 | struct held_lock *hlock; | |
2131 | int i; | |
2132 | ||
2133 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2134 | hlock = curr->held_locks + i; | |
2135 | ||
2136 | if (hardirq) { | |
2137 | if (hlock->read) | |
2138 | usage_bit = LOCK_ENABLED_HARDIRQS_READ; | |
2139 | else | |
2140 | usage_bit = LOCK_ENABLED_HARDIRQS; | |
2141 | } else { | |
2142 | if (hlock->read) | |
2143 | usage_bit = LOCK_ENABLED_SOFTIRQS_READ; | |
2144 | else | |
2145 | usage_bit = LOCK_ENABLED_SOFTIRQS; | |
2146 | } | |
4ff773bb | 2147 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2148 | return 0; |
2149 | } | |
2150 | ||
2151 | return 1; | |
2152 | } | |
2153 | ||
2154 | /* | |
2155 | * Debugging helper: via this flag we know that we are in | |
2156 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2157 | */ | |
2158 | static int early_boot_irqs_enabled; | |
2159 | ||
2160 | void early_boot_irqs_off(void) | |
2161 | { | |
2162 | early_boot_irqs_enabled = 0; | |
2163 | } | |
2164 | ||
2165 | void early_boot_irqs_on(void) | |
2166 | { | |
2167 | early_boot_irqs_enabled = 1; | |
2168 | } | |
2169 | ||
2170 | /* | |
2171 | * Hardirqs will be enabled: | |
2172 | */ | |
6afe40b4 | 2173 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2174 | { |
2175 | struct task_struct *curr = current; | |
fbb9ce95 | 2176 | |
6afe40b4 | 2177 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2178 | |
fbb9ce95 IM |
2179 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2180 | return; | |
2181 | ||
2182 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2183 | return; | |
2184 | ||
2185 | if (unlikely(curr->hardirqs_enabled)) { | |
2186 | debug_atomic_inc(&redundant_hardirqs_on); | |
2187 | return; | |
2188 | } | |
2189 | /* we'll do an OFF -> ON transition: */ | |
2190 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2191 | |
2192 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2193 | return; | |
2194 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2195 | return; | |
2196 | /* | |
2197 | * We are going to turn hardirqs on, so set the | |
2198 | * usage bit for all held locks: | |
2199 | */ | |
4ff773bb | 2200 | if (!mark_held_locks(curr, 1)) |
fbb9ce95 IM |
2201 | return; |
2202 | /* | |
2203 | * If we have softirqs enabled, then set the usage | |
2204 | * bit for all held locks. (disabled hardirqs prevented | |
2205 | * this bit from being set before) | |
2206 | */ | |
2207 | if (curr->softirqs_enabled) | |
4ff773bb | 2208 | if (!mark_held_locks(curr, 0)) |
fbb9ce95 IM |
2209 | return; |
2210 | ||
8e18257d PZ |
2211 | curr->hardirq_enable_ip = ip; |
2212 | curr->hardirq_enable_event = ++curr->irq_events; | |
2213 | debug_atomic_inc(&hardirqs_on_events); | |
2214 | } | |
81d68a96 | 2215 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2216 | |
1d09daa5 | 2217 | void trace_hardirqs_on(void) |
81d68a96 SR |
2218 | { |
2219 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2220 | } | |
8e18257d PZ |
2221 | EXPORT_SYMBOL(trace_hardirqs_on); |
2222 | ||
2223 | /* | |
2224 | * Hardirqs were disabled: | |
2225 | */ | |
6afe40b4 | 2226 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2227 | { |
2228 | struct task_struct *curr = current; | |
2229 | ||
6afe40b4 | 2230 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2231 | |
8e18257d PZ |
2232 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2233 | return; | |
2234 | ||
2235 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2236 | return; | |
2237 | ||
2238 | if (curr->hardirqs_enabled) { | |
2239 | /* | |
2240 | * We have done an ON -> OFF transition: | |
2241 | */ | |
2242 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2243 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2244 | curr->hardirq_disable_event = ++curr->irq_events; |
2245 | debug_atomic_inc(&hardirqs_off_events); | |
2246 | } else | |
2247 | debug_atomic_inc(&redundant_hardirqs_off); | |
2248 | } | |
81d68a96 | 2249 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2250 | |
1d09daa5 | 2251 | void trace_hardirqs_off(void) |
81d68a96 SR |
2252 | { |
2253 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2254 | } | |
8e18257d PZ |
2255 | EXPORT_SYMBOL(trace_hardirqs_off); |
2256 | ||
2257 | /* | |
2258 | * Softirqs will be enabled: | |
2259 | */ | |
2260 | void trace_softirqs_on(unsigned long ip) | |
2261 | { | |
2262 | struct task_struct *curr = current; | |
2263 | ||
2264 | if (unlikely(!debug_locks)) | |
2265 | return; | |
2266 | ||
2267 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2268 | return; | |
2269 | ||
2270 | if (curr->softirqs_enabled) { | |
2271 | debug_atomic_inc(&redundant_softirqs_on); | |
2272 | return; | |
2273 | } | |
2274 | ||
2275 | /* | |
2276 | * We'll do an OFF -> ON transition: | |
2277 | */ | |
2278 | curr->softirqs_enabled = 1; | |
2279 | curr->softirq_enable_ip = ip; | |
2280 | curr->softirq_enable_event = ++curr->irq_events; | |
2281 | debug_atomic_inc(&softirqs_on_events); | |
2282 | /* | |
2283 | * We are going to turn softirqs on, so set the | |
2284 | * usage bit for all held locks, if hardirqs are | |
2285 | * enabled too: | |
2286 | */ | |
2287 | if (curr->hardirqs_enabled) | |
2288 | mark_held_locks(curr, 0); | |
2289 | } | |
2290 | ||
2291 | /* | |
2292 | * Softirqs were disabled: | |
2293 | */ | |
2294 | void trace_softirqs_off(unsigned long ip) | |
2295 | { | |
2296 | struct task_struct *curr = current; | |
2297 | ||
2298 | if (unlikely(!debug_locks)) | |
2299 | return; | |
2300 | ||
2301 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2302 | return; | |
2303 | ||
2304 | if (curr->softirqs_enabled) { | |
2305 | /* | |
2306 | * We have done an ON -> OFF transition: | |
2307 | */ | |
2308 | curr->softirqs_enabled = 0; | |
2309 | curr->softirq_disable_ip = ip; | |
2310 | curr->softirq_disable_event = ++curr->irq_events; | |
2311 | debug_atomic_inc(&softirqs_off_events); | |
2312 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2313 | } else | |
2314 | debug_atomic_inc(&redundant_softirqs_off); | |
2315 | } | |
2316 | ||
2317 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) | |
2318 | { | |
2319 | /* | |
2320 | * If non-trylock use in a hardirq or softirq context, then | |
2321 | * mark the lock as used in these contexts: | |
2322 | */ | |
2323 | if (!hlock->trylock) { | |
2324 | if (hlock->read) { | |
2325 | if (curr->hardirq_context) | |
2326 | if (!mark_lock(curr, hlock, | |
2327 | LOCK_USED_IN_HARDIRQ_READ)) | |
2328 | return 0; | |
2329 | if (curr->softirq_context) | |
2330 | if (!mark_lock(curr, hlock, | |
2331 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2332 | return 0; | |
2333 | } else { | |
2334 | if (curr->hardirq_context) | |
2335 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2336 | return 0; | |
2337 | if (curr->softirq_context) | |
2338 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2339 | return 0; | |
2340 | } | |
2341 | } | |
2342 | if (!hlock->hardirqs_off) { | |
2343 | if (hlock->read) { | |
2344 | if (!mark_lock(curr, hlock, | |
2345 | LOCK_ENABLED_HARDIRQS_READ)) | |
2346 | return 0; | |
2347 | if (curr->softirqs_enabled) | |
2348 | if (!mark_lock(curr, hlock, | |
2349 | LOCK_ENABLED_SOFTIRQS_READ)) | |
2350 | return 0; | |
2351 | } else { | |
2352 | if (!mark_lock(curr, hlock, | |
2353 | LOCK_ENABLED_HARDIRQS)) | |
2354 | return 0; | |
2355 | if (curr->softirqs_enabled) | |
2356 | if (!mark_lock(curr, hlock, | |
2357 | LOCK_ENABLED_SOFTIRQS)) | |
2358 | return 0; | |
2359 | } | |
2360 | } | |
2361 | ||
2362 | return 1; | |
2363 | } | |
2364 | ||
2365 | static int separate_irq_context(struct task_struct *curr, | |
2366 | struct held_lock *hlock) | |
2367 | { | |
2368 | unsigned int depth = curr->lockdep_depth; | |
2369 | ||
2370 | /* | |
2371 | * Keep track of points where we cross into an interrupt context: | |
2372 | */ | |
2373 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2374 | curr->softirq_context; | |
2375 | if (depth) { | |
2376 | struct held_lock *prev_hlock; | |
2377 | ||
2378 | prev_hlock = curr->held_locks + depth-1; | |
2379 | /* | |
2380 | * If we cross into another context, reset the | |
2381 | * hash key (this also prevents the checking and the | |
2382 | * adding of the dependency to 'prev'): | |
2383 | */ | |
2384 | if (prev_hlock->irq_context != hlock->irq_context) | |
2385 | return 1; | |
2386 | } | |
2387 | return 0; | |
fbb9ce95 IM |
2388 | } |
2389 | ||
8e18257d | 2390 | #else |
fbb9ce95 | 2391 | |
8e18257d PZ |
2392 | static inline |
2393 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2394 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2395 | { |
8e18257d PZ |
2396 | WARN_ON(1); |
2397 | return 1; | |
2398 | } | |
fbb9ce95 | 2399 | |
8e18257d PZ |
2400 | static inline int mark_irqflags(struct task_struct *curr, |
2401 | struct held_lock *hlock) | |
2402 | { | |
2403 | return 1; | |
2404 | } | |
fbb9ce95 | 2405 | |
8e18257d PZ |
2406 | static inline int separate_irq_context(struct task_struct *curr, |
2407 | struct held_lock *hlock) | |
2408 | { | |
2409 | return 0; | |
fbb9ce95 IM |
2410 | } |
2411 | ||
8e18257d | 2412 | #endif |
fbb9ce95 IM |
2413 | |
2414 | /* | |
8e18257d | 2415 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2416 | */ |
1d09daa5 | 2417 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2418 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2419 | { |
8e18257d | 2420 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2421 | |
2422 | /* | |
8e18257d PZ |
2423 | * If already set then do not dirty the cacheline, |
2424 | * nor do any checks: | |
fbb9ce95 | 2425 | */ |
f82b217e | 2426 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2427 | return 1; |
2428 | ||
2429 | if (!graph_lock()) | |
2430 | return 0; | |
fbb9ce95 | 2431 | /* |
8e18257d | 2432 | * Make sure we didnt race: |
fbb9ce95 | 2433 | */ |
f82b217e | 2434 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2435 | graph_unlock(); |
2436 | return 1; | |
2437 | } | |
fbb9ce95 | 2438 | |
f82b217e | 2439 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2440 | |
f82b217e | 2441 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2442 | return 0; |
fbb9ce95 | 2443 | |
8e18257d PZ |
2444 | switch (new_bit) { |
2445 | case LOCK_USED_IN_HARDIRQ: | |
2446 | case LOCK_USED_IN_SOFTIRQ: | |
2447 | case LOCK_USED_IN_HARDIRQ_READ: | |
2448 | case LOCK_USED_IN_SOFTIRQ_READ: | |
2449 | case LOCK_ENABLED_HARDIRQS: | |
2450 | case LOCK_ENABLED_SOFTIRQS: | |
2451 | case LOCK_ENABLED_HARDIRQS_READ: | |
2452 | case LOCK_ENABLED_SOFTIRQS_READ: | |
2453 | ret = mark_lock_irq(curr, this, new_bit); | |
2454 | if (!ret) | |
2455 | return 0; | |
2456 | break; | |
2457 | case LOCK_USED: | |
8e18257d PZ |
2458 | debug_atomic_dec(&nr_unused_locks); |
2459 | break; | |
2460 | default: | |
2461 | if (!debug_locks_off_graph_unlock()) | |
2462 | return 0; | |
2463 | WARN_ON(1); | |
2464 | return 0; | |
2465 | } | |
fbb9ce95 | 2466 | |
8e18257d PZ |
2467 | graph_unlock(); |
2468 | ||
2469 | /* | |
2470 | * We must printk outside of the graph_lock: | |
2471 | */ | |
2472 | if (ret == 2) { | |
2473 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2474 | print_lock(this); | |
2475 | print_irqtrace_events(curr); | |
2476 | dump_stack(); | |
2477 | } | |
2478 | ||
2479 | return ret; | |
2480 | } | |
fbb9ce95 IM |
2481 | |
2482 | /* | |
2483 | * Initialize a lock instance's lock-class mapping info: | |
2484 | */ | |
2485 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2486 | struct lock_class_key *key, int subclass) |
fbb9ce95 IM |
2487 | { |
2488 | if (unlikely(!debug_locks)) | |
2489 | return; | |
2490 | ||
2491 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2492 | return; | |
2493 | if (DEBUG_LOCKS_WARN_ON(!name)) | |
2494 | return; | |
2495 | /* | |
2496 | * Sanity check, the lock-class key must be persistent: | |
2497 | */ | |
2498 | if (!static_obj(key)) { | |
2499 | printk("BUG: key %p not in .data!\n", key); | |
2500 | DEBUG_LOCKS_WARN_ON(1); | |
2501 | return; | |
2502 | } | |
2503 | lock->name = name; | |
2504 | lock->key = key; | |
d6d897ce | 2505 | lock->class_cache = NULL; |
96645678 PZ |
2506 | #ifdef CONFIG_LOCK_STAT |
2507 | lock->cpu = raw_smp_processor_id(); | |
2508 | #endif | |
4dfbb9d8 PZ |
2509 | if (subclass) |
2510 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 IM |
2511 | } |
2512 | ||
2513 | EXPORT_SYMBOL_GPL(lockdep_init_map); | |
2514 | ||
2515 | /* | |
2516 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2517 | * We maintain the dependency maps and validate the locking attempt: | |
2518 | */ | |
2519 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2520 | int trylock, int read, int check, int hardirqs_off, | |
7531e2f3 | 2521 | struct lockdep_map *nest_lock, unsigned long ip) |
fbb9ce95 IM |
2522 | { |
2523 | struct task_struct *curr = current; | |
d6d897ce | 2524 | struct lock_class *class = NULL; |
fbb9ce95 | 2525 | struct held_lock *hlock; |
fbb9ce95 IM |
2526 | unsigned int depth, id; |
2527 | int chain_head = 0; | |
2528 | u64 chain_key; | |
2529 | ||
f20786ff PZ |
2530 | if (!prove_locking) |
2531 | check = 1; | |
2532 | ||
fbb9ce95 IM |
2533 | if (unlikely(!debug_locks)) |
2534 | return 0; | |
2535 | ||
2536 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2537 | return 0; | |
2538 | ||
2539 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2540 | debug_locks_off(); | |
2541 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2542 | printk("turning off the locking correctness validator.\n"); | |
2543 | return 0; | |
2544 | } | |
2545 | ||
d6d897ce IM |
2546 | if (!subclass) |
2547 | class = lock->class_cache; | |
2548 | /* | |
2549 | * Not cached yet or subclass? | |
2550 | */ | |
fbb9ce95 | 2551 | if (unlikely(!class)) { |
4dfbb9d8 | 2552 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2553 | if (!class) |
2554 | return 0; | |
2555 | } | |
2556 | debug_atomic_inc((atomic_t *)&class->ops); | |
2557 | if (very_verbose(class)) { | |
2558 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2559 | if (class->name_version > 1) | |
2560 | printk("#%d", class->name_version); | |
2561 | printk("\n"); | |
2562 | dump_stack(); | |
2563 | } | |
2564 | ||
2565 | /* | |
2566 | * Add the lock to the list of currently held locks. | |
2567 | * (we dont increase the depth just yet, up until the | |
2568 | * dependency checks are done) | |
2569 | */ | |
2570 | depth = curr->lockdep_depth; | |
2571 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2572 | return 0; | |
2573 | ||
2574 | hlock = curr->held_locks + depth; | |
f82b217e DJ |
2575 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2576 | return 0; | |
2577 | hlock->class_idx = class - lock_classes + 1; | |
fbb9ce95 IM |
2578 | hlock->acquire_ip = ip; |
2579 | hlock->instance = lock; | |
7531e2f3 | 2580 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2581 | hlock->trylock = trylock; |
2582 | hlock->read = read; | |
2583 | hlock->check = check; | |
6951b12a | 2584 | hlock->hardirqs_off = !!hardirqs_off; |
f20786ff PZ |
2585 | #ifdef CONFIG_LOCK_STAT |
2586 | hlock->waittime_stamp = 0; | |
2587 | hlock->holdtime_stamp = sched_clock(); | |
2588 | #endif | |
fbb9ce95 | 2589 | |
8e18257d PZ |
2590 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2591 | return 0; | |
2592 | ||
fbb9ce95 | 2593 | /* mark it as used: */ |
4ff773bb | 2594 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2595 | return 0; |
8e18257d | 2596 | |
fbb9ce95 | 2597 | /* |
17aacfb9 | 2598 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2599 | * lock keys along the dependency chain. We save the hash value |
2600 | * at every step so that we can get the current hash easily | |
2601 | * after unlock. The chain hash is then used to cache dependency | |
2602 | * results. | |
2603 | * | |
2604 | * The 'key ID' is what is the most compact key value to drive | |
2605 | * the hash, not class->key. | |
2606 | */ | |
2607 | id = class - lock_classes; | |
2608 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2609 | return 0; | |
2610 | ||
2611 | chain_key = curr->curr_chain_key; | |
2612 | if (!depth) { | |
2613 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2614 | return 0; | |
2615 | chain_head = 1; | |
2616 | } | |
2617 | ||
2618 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2619 | if (separate_irq_context(curr, hlock)) { |
2620 | chain_key = 0; | |
2621 | chain_head = 1; | |
fbb9ce95 | 2622 | } |
fbb9ce95 | 2623 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2624 | |
3aa416b0 | 2625 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2626 | return 0; |
381a2292 | 2627 | |
3aa416b0 | 2628 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2629 | curr->lockdep_depth++; |
2630 | check_chain_key(curr); | |
60e114d1 JP |
2631 | #ifdef CONFIG_DEBUG_LOCKDEP |
2632 | if (unlikely(!debug_locks)) | |
2633 | return 0; | |
2634 | #endif | |
fbb9ce95 IM |
2635 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2636 | debug_locks_off(); | |
2637 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2638 | printk("turning off the locking correctness validator.\n"); | |
2639 | return 0; | |
2640 | } | |
381a2292 | 2641 | |
fbb9ce95 IM |
2642 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2643 | max_lockdep_depth = curr->lockdep_depth; | |
2644 | ||
2645 | return 1; | |
2646 | } | |
2647 | ||
2648 | static int | |
2649 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2650 | unsigned long ip) | |
2651 | { | |
2652 | if (!debug_locks_off()) | |
2653 | return 0; | |
2654 | if (debug_locks_silent) | |
2655 | return 0; | |
2656 | ||
2657 | printk("\n=====================================\n"); | |
2658 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2659 | printk( "-------------------------------------\n"); | |
2660 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2661 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2662 | print_lockdep_cache(lock); |
2663 | printk(") at:\n"); | |
2664 | print_ip_sym(ip); | |
2665 | printk("but there are no more locks to release!\n"); | |
2666 | printk("\nother info that might help us debug this:\n"); | |
2667 | lockdep_print_held_locks(curr); | |
2668 | ||
2669 | printk("\nstack backtrace:\n"); | |
2670 | dump_stack(); | |
2671 | ||
2672 | return 0; | |
2673 | } | |
2674 | ||
2675 | /* | |
2676 | * Common debugging checks for both nested and non-nested unlock: | |
2677 | */ | |
2678 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2679 | unsigned long ip) | |
2680 | { | |
2681 | if (unlikely(!debug_locks)) | |
2682 | return 0; | |
2683 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2684 | return 0; | |
2685 | ||
2686 | if (curr->lockdep_depth <= 0) | |
2687 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2688 | ||
2689 | return 1; | |
2690 | } | |
2691 | ||
64aa348e PZ |
2692 | static int |
2693 | __lock_set_subclass(struct lockdep_map *lock, | |
2694 | unsigned int subclass, unsigned long ip) | |
2695 | { | |
2696 | struct task_struct *curr = current; | |
2697 | struct held_lock *hlock, *prev_hlock; | |
2698 | struct lock_class *class; | |
2699 | unsigned int depth; | |
2700 | int i; | |
2701 | ||
2702 | depth = curr->lockdep_depth; | |
2703 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2704 | return 0; | |
2705 | ||
2706 | prev_hlock = NULL; | |
2707 | for (i = depth-1; i >= 0; i--) { | |
2708 | hlock = curr->held_locks + i; | |
2709 | /* | |
2710 | * We must not cross into another context: | |
2711 | */ | |
2712 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2713 | break; | |
2714 | if (hlock->instance == lock) | |
2715 | goto found_it; | |
2716 | prev_hlock = hlock; | |
2717 | } | |
2718 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2719 | ||
2720 | found_it: | |
2721 | class = register_lock_class(lock, subclass, 0); | |
f82b217e | 2722 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2723 | |
2724 | curr->lockdep_depth = i; | |
2725 | curr->curr_chain_key = hlock->prev_chain_key; | |
2726 | ||
2727 | for (; i < depth; i++) { | |
2728 | hlock = curr->held_locks + i; | |
2729 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2730 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2731 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2732 | hlock->nest_lock, hlock->acquire_ip)) |
64aa348e PZ |
2733 | return 0; |
2734 | } | |
2735 | ||
2736 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2737 | return 0; | |
2738 | return 1; | |
2739 | } | |
2740 | ||
fbb9ce95 IM |
2741 | /* |
2742 | * Remove the lock to the list of currently held locks in a | |
2743 | * potentially non-nested (out of order) manner. This is a | |
2744 | * relatively rare operation, as all the unlock APIs default | |
2745 | * to nested mode (which uses lock_release()): | |
2746 | */ | |
2747 | static int | |
2748 | lock_release_non_nested(struct task_struct *curr, | |
2749 | struct lockdep_map *lock, unsigned long ip) | |
2750 | { | |
2751 | struct held_lock *hlock, *prev_hlock; | |
2752 | unsigned int depth; | |
2753 | int i; | |
2754 | ||
2755 | /* | |
2756 | * Check whether the lock exists in the current stack | |
2757 | * of held locks: | |
2758 | */ | |
2759 | depth = curr->lockdep_depth; | |
2760 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2761 | return 0; | |
2762 | ||
2763 | prev_hlock = NULL; | |
2764 | for (i = depth-1; i >= 0; i--) { | |
2765 | hlock = curr->held_locks + i; | |
2766 | /* | |
2767 | * We must not cross into another context: | |
2768 | */ | |
2769 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2770 | break; | |
2771 | if (hlock->instance == lock) | |
2772 | goto found_it; | |
2773 | prev_hlock = hlock; | |
2774 | } | |
2775 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2776 | ||
2777 | found_it: | |
f20786ff PZ |
2778 | lock_release_holdtime(hlock); |
2779 | ||
fbb9ce95 IM |
2780 | /* |
2781 | * We have the right lock to unlock, 'hlock' points to it. | |
2782 | * Now we remove it from the stack, and add back the other | |
2783 | * entries (if any), recalculating the hash along the way: | |
2784 | */ | |
2785 | curr->lockdep_depth = i; | |
2786 | curr->curr_chain_key = hlock->prev_chain_key; | |
2787 | ||
2788 | for (i++; i < depth; i++) { | |
2789 | hlock = curr->held_locks + i; | |
2790 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2791 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 2792 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2793 | hlock->nest_lock, hlock->acquire_ip)) |
fbb9ce95 IM |
2794 | return 0; |
2795 | } | |
2796 | ||
2797 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2798 | return 0; | |
2799 | return 1; | |
2800 | } | |
2801 | ||
2802 | /* | |
2803 | * Remove the lock to the list of currently held locks - this gets | |
2804 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2805 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2806 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2807 | */ | |
2808 | static int lock_release_nested(struct task_struct *curr, | |
2809 | struct lockdep_map *lock, unsigned long ip) | |
2810 | { | |
2811 | struct held_lock *hlock; | |
2812 | unsigned int depth; | |
2813 | ||
2814 | /* | |
2815 | * Pop off the top of the lock stack: | |
2816 | */ | |
2817 | depth = curr->lockdep_depth - 1; | |
2818 | hlock = curr->held_locks + depth; | |
2819 | ||
2820 | /* | |
2821 | * Is the unlock non-nested: | |
2822 | */ | |
2823 | if (hlock->instance != lock) | |
2824 | return lock_release_non_nested(curr, lock, ip); | |
2825 | curr->lockdep_depth--; | |
2826 | ||
2827 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2828 | return 0; | |
2829 | ||
2830 | curr->curr_chain_key = hlock->prev_chain_key; | |
2831 | ||
f20786ff PZ |
2832 | lock_release_holdtime(hlock); |
2833 | ||
fbb9ce95 IM |
2834 | #ifdef CONFIG_DEBUG_LOCKDEP |
2835 | hlock->prev_chain_key = 0; | |
f82b217e | 2836 | hlock->class_idx = 0; |
fbb9ce95 IM |
2837 | hlock->acquire_ip = 0; |
2838 | hlock->irq_context = 0; | |
2839 | #endif | |
2840 | return 1; | |
2841 | } | |
2842 | ||
2843 | /* | |
2844 | * Remove the lock to the list of currently held locks - this gets | |
2845 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2846 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2847 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2848 | */ | |
2849 | static void | |
2850 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2851 | { | |
2852 | struct task_struct *curr = current; | |
2853 | ||
2854 | if (!check_unlock(curr, lock, ip)) | |
2855 | return; | |
2856 | ||
2857 | if (nested) { | |
2858 | if (!lock_release_nested(curr, lock, ip)) | |
2859 | return; | |
2860 | } else { | |
2861 | if (!lock_release_non_nested(curr, lock, ip)) | |
2862 | return; | |
2863 | } | |
2864 | ||
2865 | check_chain_key(curr); | |
2866 | } | |
2867 | ||
2868 | /* | |
2869 | * Check whether we follow the irq-flags state precisely: | |
2870 | */ | |
1d09daa5 | 2871 | static void check_flags(unsigned long flags) |
fbb9ce95 | 2872 | { |
992860e9 IM |
2873 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
2874 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
2875 | if (!debug_locks) |
2876 | return; | |
2877 | ||
5f9fa8a6 IM |
2878 | if (irqs_disabled_flags(flags)) { |
2879 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
2880 | printk("possible reason: unannotated irqs-off.\n"); | |
2881 | } | |
2882 | } else { | |
2883 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
2884 | printk("possible reason: unannotated irqs-on.\n"); | |
2885 | } | |
2886 | } | |
fbb9ce95 IM |
2887 | |
2888 | /* | |
2889 | * We dont accurately track softirq state in e.g. | |
2890 | * hardirq contexts (such as on 4KSTACKS), so only | |
2891 | * check if not in hardirq contexts: | |
2892 | */ | |
2893 | if (!hardirq_count()) { | |
2894 | if (softirq_count()) | |
2895 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
2896 | else | |
2897 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
2898 | } | |
2899 | ||
2900 | if (!debug_locks) | |
2901 | print_irqtrace_events(current); | |
2902 | #endif | |
2903 | } | |
2904 | ||
64aa348e PZ |
2905 | void |
2906 | lock_set_subclass(struct lockdep_map *lock, | |
2907 | unsigned int subclass, unsigned long ip) | |
2908 | { | |
2909 | unsigned long flags; | |
2910 | ||
2911 | if (unlikely(current->lockdep_recursion)) | |
2912 | return; | |
2913 | ||
2914 | raw_local_irq_save(flags); | |
2915 | current->lockdep_recursion = 1; | |
2916 | check_flags(flags); | |
2917 | if (__lock_set_subclass(lock, subclass, ip)) | |
2918 | check_chain_key(current); | |
2919 | current->lockdep_recursion = 0; | |
2920 | raw_local_irq_restore(flags); | |
2921 | } | |
2922 | ||
2923 | EXPORT_SYMBOL_GPL(lock_set_subclass); | |
2924 | ||
fbb9ce95 IM |
2925 | /* |
2926 | * We are not always called with irqs disabled - do that here, | |
2927 | * and also avoid lockdep recursion: | |
2928 | */ | |
1d09daa5 | 2929 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
2930 | int trylock, int read, int check, |
2931 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
2932 | { |
2933 | unsigned long flags; | |
2934 | ||
2935 | if (unlikely(current->lockdep_recursion)) | |
2936 | return; | |
2937 | ||
2938 | raw_local_irq_save(flags); | |
2939 | check_flags(flags); | |
2940 | ||
2941 | current->lockdep_recursion = 1; | |
2942 | __lock_acquire(lock, subclass, trylock, read, check, | |
7531e2f3 | 2943 | irqs_disabled_flags(flags), nest_lock, ip); |
fbb9ce95 IM |
2944 | current->lockdep_recursion = 0; |
2945 | raw_local_irq_restore(flags); | |
2946 | } | |
2947 | ||
2948 | EXPORT_SYMBOL_GPL(lock_acquire); | |
2949 | ||
1d09daa5 | 2950 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 2951 | unsigned long ip) |
fbb9ce95 IM |
2952 | { |
2953 | unsigned long flags; | |
2954 | ||
2955 | if (unlikely(current->lockdep_recursion)) | |
2956 | return; | |
2957 | ||
2958 | raw_local_irq_save(flags); | |
2959 | check_flags(flags); | |
2960 | current->lockdep_recursion = 1; | |
2961 | __lock_release(lock, nested, ip); | |
2962 | current->lockdep_recursion = 0; | |
2963 | raw_local_irq_restore(flags); | |
2964 | } | |
2965 | ||
2966 | EXPORT_SYMBOL_GPL(lock_release); | |
2967 | ||
f20786ff PZ |
2968 | #ifdef CONFIG_LOCK_STAT |
2969 | static int | |
2970 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2971 | unsigned long ip) | |
2972 | { | |
2973 | if (!debug_locks_off()) | |
2974 | return 0; | |
2975 | if (debug_locks_silent) | |
2976 | return 0; | |
2977 | ||
2978 | printk("\n=================================\n"); | |
2979 | printk( "[ BUG: bad contention detected! ]\n"); | |
2980 | printk( "---------------------------------\n"); | |
2981 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 2982 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
2983 | print_lockdep_cache(lock); |
2984 | printk(") at:\n"); | |
2985 | print_ip_sym(ip); | |
2986 | printk("but there are no locks held!\n"); | |
2987 | printk("\nother info that might help us debug this:\n"); | |
2988 | lockdep_print_held_locks(curr); | |
2989 | ||
2990 | printk("\nstack backtrace:\n"); | |
2991 | dump_stack(); | |
2992 | ||
2993 | return 0; | |
2994 | } | |
2995 | ||
2996 | static void | |
2997 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
2998 | { | |
2999 | struct task_struct *curr = current; | |
3000 | struct held_lock *hlock, *prev_hlock; | |
3001 | struct lock_class_stats *stats; | |
3002 | unsigned int depth; | |
3003 | int i, point; | |
3004 | ||
3005 | depth = curr->lockdep_depth; | |
3006 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3007 | return; | |
3008 | ||
3009 | prev_hlock = NULL; | |
3010 | for (i = depth-1; i >= 0; i--) { | |
3011 | hlock = curr->held_locks + i; | |
3012 | /* | |
3013 | * We must not cross into another context: | |
3014 | */ | |
3015 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3016 | break; | |
3017 | if (hlock->instance == lock) | |
3018 | goto found_it; | |
3019 | prev_hlock = hlock; | |
3020 | } | |
3021 | print_lock_contention_bug(curr, lock, ip); | |
3022 | return; | |
3023 | ||
3024 | found_it: | |
3025 | hlock->waittime_stamp = sched_clock(); | |
3026 | ||
f82b217e | 3027 | point = lock_contention_point(hlock_class(hlock), ip); |
f20786ff | 3028 | |
f82b217e | 3029 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff | 3030 | if (point < ARRAY_SIZE(stats->contention_point)) |
04148b73 | 3031 | stats->contention_point[point]++; |
96645678 PZ |
3032 | if (lock->cpu != smp_processor_id()) |
3033 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3034 | put_lock_stats(stats); |
3035 | } | |
3036 | ||
3037 | static void | |
3038 | __lock_acquired(struct lockdep_map *lock) | |
3039 | { | |
3040 | struct task_struct *curr = current; | |
3041 | struct held_lock *hlock, *prev_hlock; | |
3042 | struct lock_class_stats *stats; | |
3043 | unsigned int depth; | |
3044 | u64 now; | |
96645678 PZ |
3045 | s64 waittime = 0; |
3046 | int i, cpu; | |
f20786ff PZ |
3047 | |
3048 | depth = curr->lockdep_depth; | |
3049 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3050 | return; | |
3051 | ||
3052 | prev_hlock = NULL; | |
3053 | for (i = depth-1; i >= 0; i--) { | |
3054 | hlock = curr->held_locks + i; | |
3055 | /* | |
3056 | * We must not cross into another context: | |
3057 | */ | |
3058 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3059 | break; | |
3060 | if (hlock->instance == lock) | |
3061 | goto found_it; | |
3062 | prev_hlock = hlock; | |
3063 | } | |
3064 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3065 | return; | |
3066 | ||
3067 | found_it: | |
96645678 PZ |
3068 | cpu = smp_processor_id(); |
3069 | if (hlock->waittime_stamp) { | |
3070 | now = sched_clock(); | |
3071 | waittime = now - hlock->waittime_stamp; | |
3072 | hlock->holdtime_stamp = now; | |
3073 | } | |
f20786ff | 3074 | |
f82b217e | 3075 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3076 | if (waittime) { |
3077 | if (hlock->read) | |
3078 | lock_time_inc(&stats->read_waittime, waittime); | |
3079 | else | |
3080 | lock_time_inc(&stats->write_waittime, waittime); | |
3081 | } | |
3082 | if (lock->cpu != cpu) | |
3083 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3084 | put_lock_stats(stats); |
96645678 PZ |
3085 | |
3086 | lock->cpu = cpu; | |
f20786ff PZ |
3087 | } |
3088 | ||
3089 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3090 | { | |
3091 | unsigned long flags; | |
3092 | ||
3093 | if (unlikely(!lock_stat)) | |
3094 | return; | |
3095 | ||
3096 | if (unlikely(current->lockdep_recursion)) | |
3097 | return; | |
3098 | ||
3099 | raw_local_irq_save(flags); | |
3100 | check_flags(flags); | |
3101 | current->lockdep_recursion = 1; | |
3102 | __lock_contended(lock, ip); | |
3103 | current->lockdep_recursion = 0; | |
3104 | raw_local_irq_restore(flags); | |
3105 | } | |
3106 | EXPORT_SYMBOL_GPL(lock_contended); | |
3107 | ||
3108 | void lock_acquired(struct lockdep_map *lock) | |
3109 | { | |
3110 | unsigned long flags; | |
3111 | ||
3112 | if (unlikely(!lock_stat)) | |
3113 | return; | |
3114 | ||
3115 | if (unlikely(current->lockdep_recursion)) | |
3116 | return; | |
3117 | ||
3118 | raw_local_irq_save(flags); | |
3119 | check_flags(flags); | |
3120 | current->lockdep_recursion = 1; | |
3121 | __lock_acquired(lock); | |
3122 | current->lockdep_recursion = 0; | |
3123 | raw_local_irq_restore(flags); | |
3124 | } | |
3125 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3126 | #endif | |
3127 | ||
fbb9ce95 IM |
3128 | /* |
3129 | * Used by the testsuite, sanitize the validator state | |
3130 | * after a simulated failure: | |
3131 | */ | |
3132 | ||
3133 | void lockdep_reset(void) | |
3134 | { | |
3135 | unsigned long flags; | |
23d95a03 | 3136 | int i; |
fbb9ce95 IM |
3137 | |
3138 | raw_local_irq_save(flags); | |
3139 | current->curr_chain_key = 0; | |
3140 | current->lockdep_depth = 0; | |
3141 | current->lockdep_recursion = 0; | |
3142 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3143 | nr_hardirq_chains = 0; | |
3144 | nr_softirq_chains = 0; | |
3145 | nr_process_chains = 0; | |
3146 | debug_locks = 1; | |
23d95a03 IM |
3147 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3148 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3149 | raw_local_irq_restore(flags); |
3150 | } | |
3151 | ||
3152 | static void zap_class(struct lock_class *class) | |
3153 | { | |
3154 | int i; | |
3155 | ||
3156 | /* | |
3157 | * Remove all dependencies this lock is | |
3158 | * involved in: | |
3159 | */ | |
3160 | for (i = 0; i < nr_list_entries; i++) { | |
3161 | if (list_entries[i].class == class) | |
3162 | list_del_rcu(&list_entries[i].entry); | |
3163 | } | |
3164 | /* | |
3165 | * Unhash the class and remove it from the all_lock_classes list: | |
3166 | */ | |
3167 | list_del_rcu(&class->hash_entry); | |
3168 | list_del_rcu(&class->lock_entry); | |
3169 | ||
8bfe0298 | 3170 | class->key = NULL; |
fbb9ce95 IM |
3171 | } |
3172 | ||
fabe874a | 3173 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3174 | { |
3175 | return addr >= start && addr < start + size; | |
3176 | } | |
3177 | ||
3178 | void lockdep_free_key_range(void *start, unsigned long size) | |
3179 | { | |
3180 | struct lock_class *class, *next; | |
3181 | struct list_head *head; | |
3182 | unsigned long flags; | |
3183 | int i; | |
5a26db5b | 3184 | int locked; |
fbb9ce95 IM |
3185 | |
3186 | raw_local_irq_save(flags); | |
5a26db5b | 3187 | locked = graph_lock(); |
fbb9ce95 IM |
3188 | |
3189 | /* | |
3190 | * Unhash all classes that were created by this module: | |
3191 | */ | |
3192 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3193 | head = classhash_table + i; | |
3194 | if (list_empty(head)) | |
3195 | continue; | |
fabe874a | 3196 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3197 | if (within(class->key, start, size)) |
3198 | zap_class(class); | |
fabe874a AV |
3199 | else if (within(class->name, start, size)) |
3200 | zap_class(class); | |
3201 | } | |
fbb9ce95 IM |
3202 | } |
3203 | ||
5a26db5b NP |
3204 | if (locked) |
3205 | graph_unlock(); | |
fbb9ce95 IM |
3206 | raw_local_irq_restore(flags); |
3207 | } | |
3208 | ||
3209 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3210 | { | |
d6d897ce | 3211 | struct lock_class *class, *next; |
fbb9ce95 IM |
3212 | struct list_head *head; |
3213 | unsigned long flags; | |
3214 | int i, j; | |
5a26db5b | 3215 | int locked; |
fbb9ce95 IM |
3216 | |
3217 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3218 | |
3219 | /* | |
d6d897ce IM |
3220 | * Remove all classes this lock might have: |
3221 | */ | |
3222 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3223 | /* | |
3224 | * If the class exists we look it up and zap it: | |
3225 | */ | |
3226 | class = look_up_lock_class(lock, j); | |
3227 | if (class) | |
3228 | zap_class(class); | |
3229 | } | |
3230 | /* | |
3231 | * Debug check: in the end all mapped classes should | |
3232 | * be gone. | |
fbb9ce95 | 3233 | */ |
5a26db5b | 3234 | locked = graph_lock(); |
fbb9ce95 IM |
3235 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3236 | head = classhash_table + i; | |
3237 | if (list_empty(head)) | |
3238 | continue; | |
3239 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3240 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3241 | if (debug_locks_off_graph_unlock()) |
3242 | WARN_ON(1); | |
d6d897ce | 3243 | goto out_restore; |
fbb9ce95 IM |
3244 | } |
3245 | } | |
3246 | } | |
5a26db5b NP |
3247 | if (locked) |
3248 | graph_unlock(); | |
d6d897ce IM |
3249 | |
3250 | out_restore: | |
fbb9ce95 IM |
3251 | raw_local_irq_restore(flags); |
3252 | } | |
3253 | ||
1499993c | 3254 | void lockdep_init(void) |
fbb9ce95 IM |
3255 | { |
3256 | int i; | |
3257 | ||
3258 | /* | |
3259 | * Some architectures have their own start_kernel() | |
3260 | * code which calls lockdep_init(), while we also | |
3261 | * call lockdep_init() from the start_kernel() itself, | |
3262 | * and we want to initialize the hashes only once: | |
3263 | */ | |
3264 | if (lockdep_initialized) | |
3265 | return; | |
3266 | ||
3267 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3268 | INIT_LIST_HEAD(classhash_table + i); | |
3269 | ||
3270 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3271 | INIT_LIST_HEAD(chainhash_table + i); | |
3272 | ||
3273 | lockdep_initialized = 1; | |
3274 | } | |
3275 | ||
3276 | void __init lockdep_info(void) | |
3277 | { | |
3278 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3279 | ||
b0788caf | 3280 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3281 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3282 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3283 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3284 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3285 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3286 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3287 | ||
3288 | printk(" memory used by lock dependency info: %lu kB\n", | |
3289 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3290 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3291 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3292 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
3293 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
3294 | ||
3295 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3296 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3297 | ||
3298 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3299 | if (lockdep_init_error) { |
3300 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3301 | printk("Call stack leading to lockdep invocation was:\n"); | |
3302 | print_stack_trace(&lockdep_init_trace, 0); | |
3303 | } | |
fbb9ce95 IM |
3304 | #endif |
3305 | } | |
3306 | ||
fbb9ce95 IM |
3307 | static void |
3308 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3309 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3310 | { |
3311 | if (!debug_locks_off()) | |
3312 | return; | |
3313 | if (debug_locks_silent) | |
3314 | return; | |
3315 | ||
3316 | printk("\n=========================\n"); | |
3317 | printk( "[ BUG: held lock freed! ]\n"); | |
3318 | printk( "-------------------------\n"); | |
3319 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3320 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3321 | print_lock(hlock); |
fbb9ce95 IM |
3322 | lockdep_print_held_locks(curr); |
3323 | ||
3324 | printk("\nstack backtrace:\n"); | |
3325 | dump_stack(); | |
3326 | } | |
3327 | ||
54561783 ON |
3328 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3329 | const void* lock_from, unsigned long lock_len) | |
3330 | { | |
3331 | return lock_from + lock_len <= mem_from || | |
3332 | mem_from + mem_len <= lock_from; | |
3333 | } | |
3334 | ||
fbb9ce95 IM |
3335 | /* |
3336 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3337 | * is destroyed or reinitialized - this code checks whether there is | |
3338 | * any held lock in the memory range of <from> to <to>: | |
3339 | */ | |
3340 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3341 | { | |
fbb9ce95 IM |
3342 | struct task_struct *curr = current; |
3343 | struct held_lock *hlock; | |
3344 | unsigned long flags; | |
3345 | int i; | |
3346 | ||
3347 | if (unlikely(!debug_locks)) | |
3348 | return; | |
3349 | ||
3350 | local_irq_save(flags); | |
3351 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3352 | hlock = curr->held_locks + i; | |
3353 | ||
54561783 ON |
3354 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3355 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3356 | continue; |
3357 | ||
54561783 | 3358 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3359 | break; |
3360 | } | |
3361 | local_irq_restore(flags); | |
3362 | } | |
ed07536e | 3363 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3364 | |
3365 | static void print_held_locks_bug(struct task_struct *curr) | |
3366 | { | |
3367 | if (!debug_locks_off()) | |
3368 | return; | |
3369 | if (debug_locks_silent) | |
3370 | return; | |
3371 | ||
3372 | printk("\n=====================================\n"); | |
3373 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3374 | printk( "-------------------------------------\n"); | |
3375 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3376 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3377 | lockdep_print_held_locks(curr); |
3378 | ||
3379 | printk("\nstack backtrace:\n"); | |
3380 | dump_stack(); | |
3381 | } | |
3382 | ||
3383 | void debug_check_no_locks_held(struct task_struct *task) | |
3384 | { | |
3385 | if (unlikely(task->lockdep_depth > 0)) | |
3386 | print_held_locks_bug(task); | |
3387 | } | |
3388 | ||
3389 | void debug_show_all_locks(void) | |
3390 | { | |
3391 | struct task_struct *g, *p; | |
3392 | int count = 10; | |
3393 | int unlock = 1; | |
3394 | ||
9c35dd7f JP |
3395 | if (unlikely(!debug_locks)) { |
3396 | printk("INFO: lockdep is turned off.\n"); | |
3397 | return; | |
3398 | } | |
fbb9ce95 IM |
3399 | printk("\nShowing all locks held in the system:\n"); |
3400 | ||
3401 | /* | |
3402 | * Here we try to get the tasklist_lock as hard as possible, | |
3403 | * if not successful after 2 seconds we ignore it (but keep | |
3404 | * trying). This is to enable a debug printout even if a | |
3405 | * tasklist_lock-holding task deadlocks or crashes. | |
3406 | */ | |
3407 | retry: | |
3408 | if (!read_trylock(&tasklist_lock)) { | |
3409 | if (count == 10) | |
3410 | printk("hm, tasklist_lock locked, retrying... "); | |
3411 | if (count) { | |
3412 | count--; | |
3413 | printk(" #%d", 10-count); | |
3414 | mdelay(200); | |
3415 | goto retry; | |
3416 | } | |
3417 | printk(" ignoring it.\n"); | |
3418 | unlock = 0; | |
46fec7ac | 3419 | } else { |
3420 | if (count != 10) | |
3421 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3422 | } |
fbb9ce95 IM |
3423 | |
3424 | do_each_thread(g, p) { | |
85684873 IM |
3425 | /* |
3426 | * It's not reliable to print a task's held locks | |
3427 | * if it's not sleeping (or if it's not the current | |
3428 | * task): | |
3429 | */ | |
3430 | if (p->state == TASK_RUNNING && p != current) | |
3431 | continue; | |
fbb9ce95 IM |
3432 | if (p->lockdep_depth) |
3433 | lockdep_print_held_locks(p); | |
3434 | if (!unlock) | |
3435 | if (read_trylock(&tasklist_lock)) | |
3436 | unlock = 1; | |
3437 | } while_each_thread(g, p); | |
3438 | ||
3439 | printk("\n"); | |
3440 | printk("=============================================\n\n"); | |
3441 | ||
3442 | if (unlock) | |
3443 | read_unlock(&tasklist_lock); | |
3444 | } | |
3445 | ||
3446 | EXPORT_SYMBOL_GPL(debug_show_all_locks); | |
3447 | ||
82a1fcb9 IM |
3448 | /* |
3449 | * Careful: only use this function if you are sure that | |
3450 | * the task cannot run in parallel! | |
3451 | */ | |
3452 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3453 | { |
9c35dd7f JP |
3454 | if (unlikely(!debug_locks)) { |
3455 | printk("INFO: lockdep is turned off.\n"); | |
3456 | return; | |
3457 | } | |
fbb9ce95 IM |
3458 | lockdep_print_held_locks(task); |
3459 | } | |
82a1fcb9 IM |
3460 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3461 | ||
3462 | void debug_show_held_locks(struct task_struct *task) | |
3463 | { | |
3464 | __debug_show_held_locks(task); | |
3465 | } | |
fbb9ce95 IM |
3466 | |
3467 | EXPORT_SYMBOL_GPL(debug_show_held_locks); | |
b351d164 PZ |
3468 | |
3469 | void lockdep_sys_exit(void) | |
3470 | { | |
3471 | struct task_struct *curr = current; | |
3472 | ||
3473 | if (unlikely(curr->lockdep_depth)) { | |
3474 | if (!debug_locks_off()) | |
3475 | return; | |
3476 | printk("\n================================================\n"); | |
3477 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3478 | printk( "------------------------------------------------\n"); | |
3479 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3480 | curr->comm, curr->pid); | |
3481 | lockdep_print_held_locks(curr); | |
3482 | } | |
3483 | } |