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