]>
Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
8 | * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
9 | * | |
10 | * this code maps all the lock dependencies as they occur in a live kernel | |
11 | * and will warn about the following classes of locking bugs: | |
12 | * | |
13 | * - lock inversion scenarios | |
14 | * - circular lock dependencies | |
15 | * - hardirq/softirq safe/unsafe locking bugs | |
16 | * | |
17 | * Bugs are reported even if the current locking scenario does not cause | |
18 | * any deadlock at this point. | |
19 | * | |
20 | * I.e. if anytime in the past two locks were taken in a different order, | |
21 | * even if it happened for another task, even if those were different | |
22 | * locks (but of the same class as this lock), this code will detect it. | |
23 | * | |
24 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
25 | * mapping lock dependencies runtime. | |
26 | */ | |
27 | #include <linux/mutex.h> | |
28 | #include <linux/sched.h> | |
29 | #include <linux/delay.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/proc_fs.h> | |
32 | #include <linux/seq_file.h> | |
33 | #include <linux/spinlock.h> | |
34 | #include <linux/kallsyms.h> | |
35 | #include <linux/interrupt.h> | |
36 | #include <linux/stacktrace.h> | |
37 | #include <linux/debug_locks.h> | |
38 | #include <linux/irqflags.h> | |
99de055a | 39 | #include <linux/utsname.h> |
fbb9ce95 IM |
40 | |
41 | #include <asm/sections.h> | |
42 | ||
43 | #include "lockdep_internals.h" | |
44 | ||
45 | /* | |
74c383f1 IM |
46 | * lockdep_lock: protects the lockdep graph, the hashes and the |
47 | * class/list/hash allocators. | |
fbb9ce95 IM |
48 | * |
49 | * This is one of the rare exceptions where it's justified | |
50 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 51 | * code to recurse back into the lockdep code... |
fbb9ce95 | 52 | */ |
74c383f1 IM |
53 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
54 | ||
55 | static int graph_lock(void) | |
56 | { | |
57 | __raw_spin_lock(&lockdep_lock); | |
58 | /* | |
59 | * Make sure that if another CPU detected a bug while | |
60 | * walking the graph we dont change it (while the other | |
61 | * CPU is busy printing out stuff with the graph lock | |
62 | * dropped already) | |
63 | */ | |
64 | if (!debug_locks) { | |
65 | __raw_spin_unlock(&lockdep_lock); | |
66 | return 0; | |
67 | } | |
68 | return 1; | |
69 | } | |
70 | ||
71 | static inline int graph_unlock(void) | |
72 | { | |
381a2292 JP |
73 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
74 | return DEBUG_LOCKS_WARN_ON(1); | |
75 | ||
74c383f1 IM |
76 | __raw_spin_unlock(&lockdep_lock); |
77 | return 0; | |
78 | } | |
79 | ||
80 | /* | |
81 | * Turn lock debugging off and return with 0 if it was off already, | |
82 | * and also release the graph lock: | |
83 | */ | |
84 | static inline int debug_locks_off_graph_unlock(void) | |
85 | { | |
86 | int ret = debug_locks_off(); | |
87 | ||
88 | __raw_spin_unlock(&lockdep_lock); | |
89 | ||
90 | return ret; | |
91 | } | |
fbb9ce95 IM |
92 | |
93 | static int lockdep_initialized; | |
94 | ||
95 | unsigned long nr_list_entries; | |
96 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; | |
97 | ||
ca58abcb | 98 | #ifdef CONFIG_PROVE_LOCKING |
fbb9ce95 | 99 | /* |
74c383f1 | 100 | * Allocate a lockdep entry. (assumes the graph_lock held, returns |
fbb9ce95 IM |
101 | * with NULL on failure) |
102 | */ | |
103 | static struct lock_list *alloc_list_entry(void) | |
104 | { | |
105 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
74c383f1 IM |
106 | if (!debug_locks_off_graph_unlock()) |
107 | return NULL; | |
108 | ||
fbb9ce95 IM |
109 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); |
110 | printk("turning off the locking correctness validator.\n"); | |
111 | return NULL; | |
112 | } | |
113 | return list_entries + nr_list_entries++; | |
114 | } | |
ca58abcb | 115 | #endif |
fbb9ce95 IM |
116 | |
117 | /* | |
118 | * All data structures here are protected by the global debug_lock. | |
119 | * | |
120 | * Mutex key structs only get allocated, once during bootup, and never | |
121 | * get freed - this significantly simplifies the debugging code. | |
122 | */ | |
123 | unsigned long nr_lock_classes; | |
124 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
125 | ||
126 | /* | |
127 | * We keep a global list of all lock classes. The list only grows, | |
128 | * never shrinks. The list is only accessed with the lockdep | |
129 | * spinlock lock held. | |
130 | */ | |
131 | LIST_HEAD(all_lock_classes); | |
132 | ||
133 | /* | |
134 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
135 | */ | |
136 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
137 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
138 | #define CLASSHASH_MASK (CLASSHASH_SIZE - 1) | |
139 | #define __classhashfn(key) ((((unsigned long)key >> CLASSHASH_BITS) + (unsigned long)key) & CLASSHASH_MASK) | |
140 | #define classhashentry(key) (classhash_table + __classhashfn((key))) | |
141 | ||
142 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
143 | ||
144 | unsigned long nr_lock_chains; | |
ca58abcb | 145 | #ifdef CONFIG_PROVE_LOCKING |
fbb9ce95 | 146 | static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
ca58abcb | 147 | #endif |
fbb9ce95 IM |
148 | |
149 | /* | |
150 | * We put the lock dependency chains into a hash-table as well, to cache | |
151 | * their existence: | |
152 | */ | |
153 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
154 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
155 | #define CHAINHASH_MASK (CHAINHASH_SIZE - 1) | |
156 | #define __chainhashfn(chain) \ | |
157 | (((chain >> CHAINHASH_BITS) + chain) & CHAINHASH_MASK) | |
158 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) | |
159 | ||
160 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
161 | ||
162 | /* | |
163 | * The hash key of the lock dependency chains is a hash itself too: | |
164 | * it's a hash of all locks taken up to that lock, including that lock. | |
165 | * It's a 64-bit hash, because it's important for the keys to be | |
166 | * unique. | |
167 | */ | |
168 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
169 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
170 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
171 | (key2)) |
172 | ||
173 | void lockdep_off(void) | |
174 | { | |
175 | current->lockdep_recursion++; | |
176 | } | |
177 | ||
178 | EXPORT_SYMBOL(lockdep_off); | |
179 | ||
180 | void lockdep_on(void) | |
181 | { | |
182 | current->lockdep_recursion--; | |
183 | } | |
184 | ||
185 | EXPORT_SYMBOL(lockdep_on); | |
186 | ||
fbb9ce95 IM |
187 | /* |
188 | * Debugging switches: | |
189 | */ | |
190 | ||
191 | #define VERBOSE 0 | |
33e94e96 | 192 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
193 | |
194 | #if VERBOSE | |
195 | # define HARDIRQ_VERBOSE 1 | |
196 | # define SOFTIRQ_VERBOSE 1 | |
197 | #else | |
198 | # define HARDIRQ_VERBOSE 0 | |
199 | # define SOFTIRQ_VERBOSE 0 | |
200 | #endif | |
201 | ||
202 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE | |
203 | /* | |
204 | * Quick filtering for interesting events: | |
205 | */ | |
206 | static int class_filter(struct lock_class *class) | |
207 | { | |
f9829cce AK |
208 | #if 0 |
209 | /* Example */ | |
fbb9ce95 | 210 | if (class->name_version == 1 && |
f9829cce | 211 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
212 | return 1; |
213 | if (class->name_version == 1 && | |
f9829cce | 214 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 215 | return 1; |
f9829cce | 216 | #endif |
a6640897 IM |
217 | /* Filter everything else. 1 would be to allow everything else */ |
218 | return 0; | |
fbb9ce95 IM |
219 | } |
220 | #endif | |
221 | ||
222 | static int verbose(struct lock_class *class) | |
223 | { | |
224 | #if VERBOSE | |
225 | return class_filter(class); | |
226 | #endif | |
227 | return 0; | |
228 | } | |
229 | ||
230 | #ifdef CONFIG_TRACE_IRQFLAGS | |
231 | ||
232 | static int hardirq_verbose(struct lock_class *class) | |
233 | { | |
234 | #if HARDIRQ_VERBOSE | |
235 | return class_filter(class); | |
236 | #endif | |
237 | return 0; | |
238 | } | |
239 | ||
240 | static int softirq_verbose(struct lock_class *class) | |
241 | { | |
242 | #if SOFTIRQ_VERBOSE | |
243 | return class_filter(class); | |
244 | #endif | |
245 | return 0; | |
246 | } | |
247 | ||
248 | #endif | |
249 | ||
250 | /* | |
251 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 252 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
253 | */ |
254 | unsigned long nr_stack_trace_entries; | |
255 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
256 | ||
257 | static int save_trace(struct stack_trace *trace) | |
258 | { | |
259 | trace->nr_entries = 0; | |
260 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
261 | trace->entries = stack_trace + nr_stack_trace_entries; | |
262 | ||
5a1b3999 | 263 | trace->skip = 3; |
5a1b3999 | 264 | |
ab1b6f03 | 265 | save_stack_trace(trace); |
fbb9ce95 IM |
266 | |
267 | trace->max_entries = trace->nr_entries; | |
268 | ||
269 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
270 | |
271 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
272 | if (!debug_locks_off_graph_unlock()) |
273 | return 0; | |
274 | ||
275 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
276 | printk("turning off the locking correctness validator.\n"); | |
277 | dump_stack(); | |
278 | ||
fbb9ce95 IM |
279 | return 0; |
280 | } | |
281 | ||
282 | return 1; | |
283 | } | |
284 | ||
285 | unsigned int nr_hardirq_chains; | |
286 | unsigned int nr_softirq_chains; | |
287 | unsigned int nr_process_chains; | |
288 | unsigned int max_lockdep_depth; | |
289 | unsigned int max_recursion_depth; | |
290 | ||
291 | #ifdef CONFIG_DEBUG_LOCKDEP | |
292 | /* | |
293 | * We cannot printk in early bootup code. Not even early_printk() | |
294 | * might work. So we mark any initialization errors and printk | |
295 | * about it later on, in lockdep_info(). | |
296 | */ | |
297 | static int lockdep_init_error; | |
298 | ||
299 | /* | |
300 | * Various lockdep statistics: | |
301 | */ | |
302 | atomic_t chain_lookup_hits; | |
303 | atomic_t chain_lookup_misses; | |
304 | atomic_t hardirqs_on_events; | |
305 | atomic_t hardirqs_off_events; | |
306 | atomic_t redundant_hardirqs_on; | |
307 | atomic_t redundant_hardirqs_off; | |
308 | atomic_t softirqs_on_events; | |
309 | atomic_t softirqs_off_events; | |
310 | atomic_t redundant_softirqs_on; | |
311 | atomic_t redundant_softirqs_off; | |
312 | atomic_t nr_unused_locks; | |
313 | atomic_t nr_cyclic_checks; | |
314 | atomic_t nr_cyclic_check_recursions; | |
315 | atomic_t nr_find_usage_forwards_checks; | |
316 | atomic_t nr_find_usage_forwards_recursions; | |
317 | atomic_t nr_find_usage_backwards_checks; | |
318 | atomic_t nr_find_usage_backwards_recursions; | |
319 | # define debug_atomic_inc(ptr) atomic_inc(ptr) | |
320 | # define debug_atomic_dec(ptr) atomic_dec(ptr) | |
321 | # define debug_atomic_read(ptr) atomic_read(ptr) | |
322 | #else | |
323 | # define debug_atomic_inc(ptr) do { } while (0) | |
324 | # define debug_atomic_dec(ptr) do { } while (0) | |
325 | # define debug_atomic_read(ptr) 0 | |
326 | #endif | |
327 | ||
328 | /* | |
329 | * Locking printouts: | |
330 | */ | |
331 | ||
332 | static const char *usage_str[] = | |
333 | { | |
334 | [LOCK_USED] = "initial-use ", | |
335 | [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W", | |
336 | [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W", | |
337 | [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W", | |
338 | [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W", | |
339 | [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R", | |
340 | [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R", | |
341 | [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R", | |
342 | [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R", | |
343 | }; | |
344 | ||
345 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
346 | { | |
ffb45122 | 347 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
348 | } |
349 | ||
350 | void | |
351 | get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4) | |
352 | { | |
353 | *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.'; | |
354 | ||
355 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) | |
356 | *c1 = '+'; | |
357 | else | |
358 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) | |
359 | *c1 = '-'; | |
360 | ||
361 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) | |
362 | *c2 = '+'; | |
363 | else | |
364 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) | |
365 | *c2 = '-'; | |
366 | ||
367 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
368 | *c3 = '-'; | |
369 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { | |
370 | *c3 = '+'; | |
371 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
372 | *c3 = '?'; | |
373 | } | |
374 | ||
375 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
376 | *c4 = '-'; | |
377 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { | |
378 | *c4 = '+'; | |
379 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
380 | *c4 = '?'; | |
381 | } | |
382 | } | |
383 | ||
384 | static void print_lock_name(struct lock_class *class) | |
385 | { | |
9281acea | 386 | char str[KSYM_NAME_LEN], c1, c2, c3, c4; |
fbb9ce95 IM |
387 | const char *name; |
388 | ||
389 | get_usage_chars(class, &c1, &c2, &c3, &c4); | |
390 | ||
391 | name = class->name; | |
392 | if (!name) { | |
393 | name = __get_key_name(class->key, str); | |
394 | printk(" (%s", name); | |
395 | } else { | |
396 | printk(" (%s", name); | |
397 | if (class->name_version > 1) | |
398 | printk("#%d", class->name_version); | |
399 | if (class->subclass) | |
400 | printk("/%d", class->subclass); | |
401 | } | |
402 | printk("){%c%c%c%c}", c1, c2, c3, c4); | |
403 | } | |
404 | ||
405 | static void print_lockdep_cache(struct lockdep_map *lock) | |
406 | { | |
407 | const char *name; | |
9281acea | 408 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
409 | |
410 | name = lock->name; | |
411 | if (!name) | |
412 | name = __get_key_name(lock->key->subkeys, str); | |
413 | ||
414 | printk("%s", name); | |
415 | } | |
416 | ||
417 | static void print_lock(struct held_lock *hlock) | |
418 | { | |
419 | print_lock_name(hlock->class); | |
420 | printk(", at: "); | |
421 | print_ip_sym(hlock->acquire_ip); | |
422 | } | |
423 | ||
424 | static void lockdep_print_held_locks(struct task_struct *curr) | |
425 | { | |
426 | int i, depth = curr->lockdep_depth; | |
427 | ||
428 | if (!depth) { | |
429 | printk("no locks held by %s/%d.\n", curr->comm, curr->pid); | |
430 | return; | |
431 | } | |
432 | printk("%d lock%s held by %s/%d:\n", | |
433 | depth, depth > 1 ? "s" : "", curr->comm, curr->pid); | |
434 | ||
435 | for (i = 0; i < depth; i++) { | |
436 | printk(" #%d: ", i); | |
437 | print_lock(curr->held_locks + i); | |
438 | } | |
439 | } | |
fbb9ce95 IM |
440 | |
441 | static void print_lock_class_header(struct lock_class *class, int depth) | |
442 | { | |
443 | int bit; | |
444 | ||
f9829cce | 445 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
446 | print_lock_name(class); |
447 | printk(" ops: %lu", class->ops); | |
448 | printk(" {\n"); | |
449 | ||
450 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
451 | if (class->usage_mask & (1 << bit)) { | |
452 | int len = depth; | |
453 | ||
f9829cce | 454 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
455 | len += printk(" at:\n"); |
456 | print_stack_trace(class->usage_traces + bit, len); | |
457 | } | |
458 | } | |
f9829cce | 459 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 460 | |
f9829cce | 461 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
462 | print_ip_sym((unsigned long)class->key); |
463 | } | |
464 | ||
465 | /* | |
466 | * printk all lock dependencies starting at <entry>: | |
467 | */ | |
468 | static void print_lock_dependencies(struct lock_class *class, int depth) | |
469 | { | |
470 | struct lock_list *entry; | |
471 | ||
472 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) | |
473 | return; | |
474 | ||
475 | print_lock_class_header(class, depth); | |
476 | ||
477 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
478 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
479 | return; | |
480 | ||
fbb9ce95 IM |
481 | print_lock_dependencies(entry->class, depth + 1); |
482 | ||
f9829cce | 483 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
484 | print_stack_trace(&entry->trace, 2); |
485 | printk("\n"); | |
486 | } | |
487 | } | |
488 | ||
ca58abcb | 489 | #ifdef CONFIG_PROVE_LOCKING |
fbb9ce95 IM |
490 | /* |
491 | * Add a new dependency to the head of the list: | |
492 | */ | |
493 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
068135e6 | 494 | struct list_head *head, unsigned long ip, int distance) |
fbb9ce95 IM |
495 | { |
496 | struct lock_list *entry; | |
497 | /* | |
498 | * Lock not present yet - get a new dependency struct and | |
499 | * add it to the list: | |
500 | */ | |
501 | entry = alloc_list_entry(); | |
502 | if (!entry) | |
503 | return 0; | |
504 | ||
505 | entry->class = this; | |
068135e6 | 506 | entry->distance = distance; |
910b1b2e JP |
507 | if (!save_trace(&entry->trace)) |
508 | return 0; | |
fbb9ce95 IM |
509 | |
510 | /* | |
511 | * Since we never remove from the dependency list, the list can | |
512 | * be walked lockless by other CPUs, it's only allocation | |
513 | * that must be protected by the spinlock. But this also means | |
514 | * we must make new entries visible only once writes to the | |
515 | * entry become visible - hence the RCU op: | |
516 | */ | |
517 | list_add_tail_rcu(&entry->entry, head); | |
518 | ||
519 | return 1; | |
520 | } | |
521 | ||
522 | /* | |
523 | * Recursive, forwards-direction lock-dependency checking, used for | |
524 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
525 | * checking. | |
526 | * | |
527 | * (to keep the stackframe of the recursive functions small we | |
528 | * use these global variables, and we also mark various helper | |
529 | * functions as noinline.) | |
530 | */ | |
531 | static struct held_lock *check_source, *check_target; | |
532 | ||
533 | /* | |
534 | * Print a dependency chain entry (this is only done when a deadlock | |
535 | * has been detected): | |
536 | */ | |
537 | static noinline int | |
538 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |
539 | { | |
540 | if (debug_locks_silent) | |
541 | return 0; | |
542 | printk("\n-> #%u", depth); | |
543 | print_lock_name(target->class); | |
544 | printk(":\n"); | |
545 | print_stack_trace(&target->trace, 6); | |
546 | ||
547 | return 0; | |
548 | } | |
ca58abcb | 549 | #endif |
fbb9ce95 | 550 | |
99de055a DJ |
551 | static void print_kernel_version(void) |
552 | { | |
96b644bd SH |
553 | printk("%s %.*s\n", init_utsname()->release, |
554 | (int)strcspn(init_utsname()->version, " "), | |
555 | init_utsname()->version); | |
99de055a DJ |
556 | } |
557 | ||
ca58abcb | 558 | #ifdef CONFIG_PROVE_LOCKING |
fbb9ce95 IM |
559 | /* |
560 | * When a circular dependency is detected, print the | |
561 | * header first: | |
562 | */ | |
563 | static noinline int | |
564 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) | |
565 | { | |
566 | struct task_struct *curr = current; | |
567 | ||
74c383f1 | 568 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
569 | return 0; |
570 | ||
571 | printk("\n=======================================================\n"); | |
572 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
99de055a | 573 | print_kernel_version(); |
fbb9ce95 IM |
574 | printk( "-------------------------------------------------------\n"); |
575 | printk("%s/%d is trying to acquire lock:\n", | |
576 | curr->comm, curr->pid); | |
577 | print_lock(check_source); | |
578 | printk("\nbut task is already holding lock:\n"); | |
579 | print_lock(check_target); | |
580 | printk("\nwhich lock already depends on the new lock.\n\n"); | |
581 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
582 | ||
583 | print_circular_bug_entry(entry, depth); | |
584 | ||
585 | return 0; | |
586 | } | |
587 | ||
588 | static noinline int print_circular_bug_tail(void) | |
589 | { | |
590 | struct task_struct *curr = current; | |
591 | struct lock_list this; | |
592 | ||
593 | if (debug_locks_silent) | |
594 | return 0; | |
595 | ||
596 | this.class = check_source->class; | |
910b1b2e JP |
597 | if (!save_trace(&this.trace)) |
598 | return 0; | |
74c383f1 | 599 | |
fbb9ce95 IM |
600 | print_circular_bug_entry(&this, 0); |
601 | ||
602 | printk("\nother info that might help us debug this:\n\n"); | |
603 | lockdep_print_held_locks(curr); | |
604 | ||
605 | printk("\nstack backtrace:\n"); | |
606 | dump_stack(); | |
607 | ||
608 | return 0; | |
609 | } | |
610 | ||
ca268c69 IM |
611 | #define RECURSION_LIMIT 40 |
612 | ||
fbb9ce95 IM |
613 | static int noinline print_infinite_recursion_bug(void) |
614 | { | |
74c383f1 IM |
615 | if (!debug_locks_off_graph_unlock()) |
616 | return 0; | |
617 | ||
618 | WARN_ON(1); | |
fbb9ce95 IM |
619 | |
620 | return 0; | |
621 | } | |
622 | ||
623 | /* | |
624 | * Prove that the dependency graph starting at <entry> can not | |
625 | * lead to <target>. Print an error and return 0 if it does. | |
626 | */ | |
627 | static noinline int | |
628 | check_noncircular(struct lock_class *source, unsigned int depth) | |
629 | { | |
630 | struct lock_list *entry; | |
631 | ||
632 | debug_atomic_inc(&nr_cyclic_check_recursions); | |
633 | if (depth > max_recursion_depth) | |
634 | max_recursion_depth = depth; | |
ca268c69 | 635 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
636 | return print_infinite_recursion_bug(); |
637 | /* | |
638 | * Check this lock's dependency list: | |
639 | */ | |
640 | list_for_each_entry(entry, &source->locks_after, entry) { | |
641 | if (entry->class == check_target->class) | |
642 | return print_circular_bug_header(entry, depth+1); | |
643 | debug_atomic_inc(&nr_cyclic_checks); | |
644 | if (!check_noncircular(entry->class, depth+1)) | |
645 | return print_circular_bug_entry(entry, depth+1); | |
646 | } | |
647 | return 1; | |
648 | } | |
ca58abcb | 649 | #endif |
fbb9ce95 IM |
650 | |
651 | static int very_verbose(struct lock_class *class) | |
652 | { | |
653 | #if VERY_VERBOSE | |
654 | return class_filter(class); | |
655 | #endif | |
656 | return 0; | |
657 | } | |
658 | #ifdef CONFIG_TRACE_IRQFLAGS | |
659 | ||
660 | /* | |
661 | * Forwards and backwards subgraph searching, for the purposes of | |
662 | * proving that two subgraphs can be connected by a new dependency | |
663 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
664 | */ | |
665 | static enum lock_usage_bit find_usage_bit; | |
666 | static struct lock_class *forwards_match, *backwards_match; | |
667 | ||
668 | /* | |
669 | * Find a node in the forwards-direction dependency sub-graph starting | |
670 | * at <source> that matches <find_usage_bit>. | |
671 | * | |
672 | * Return 2 if such a node exists in the subgraph, and put that node | |
673 | * into <forwards_match>. | |
674 | * | |
675 | * Return 1 otherwise and keep <forwards_match> unchanged. | |
676 | * Return 0 on error. | |
677 | */ | |
678 | static noinline int | |
679 | find_usage_forwards(struct lock_class *source, unsigned int depth) | |
680 | { | |
681 | struct lock_list *entry; | |
682 | int ret; | |
683 | ||
684 | if (depth > max_recursion_depth) | |
685 | max_recursion_depth = depth; | |
ca268c69 | 686 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
687 | return print_infinite_recursion_bug(); |
688 | ||
689 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
690 | if (source->usage_mask & (1 << find_usage_bit)) { | |
691 | forwards_match = source; | |
692 | return 2; | |
693 | } | |
694 | ||
695 | /* | |
696 | * Check this lock's dependency list: | |
697 | */ | |
698 | list_for_each_entry(entry, &source->locks_after, entry) { | |
699 | debug_atomic_inc(&nr_find_usage_forwards_recursions); | |
700 | ret = find_usage_forwards(entry->class, depth+1); | |
701 | if (ret == 2 || ret == 0) | |
702 | return ret; | |
703 | } | |
704 | return 1; | |
705 | } | |
706 | ||
707 | /* | |
708 | * Find a node in the backwards-direction dependency sub-graph starting | |
709 | * at <source> that matches <find_usage_bit>. | |
710 | * | |
711 | * Return 2 if such a node exists in the subgraph, and put that node | |
712 | * into <backwards_match>. | |
713 | * | |
714 | * Return 1 otherwise and keep <backwards_match> unchanged. | |
715 | * Return 0 on error. | |
716 | */ | |
717 | static noinline int | |
718 | find_usage_backwards(struct lock_class *source, unsigned int depth) | |
719 | { | |
720 | struct lock_list *entry; | |
721 | int ret; | |
722 | ||
381a2292 JP |
723 | if (!__raw_spin_is_locked(&lockdep_lock)) |
724 | return DEBUG_LOCKS_WARN_ON(1); | |
725 | ||
fbb9ce95 IM |
726 | if (depth > max_recursion_depth) |
727 | max_recursion_depth = depth; | |
ca268c69 | 728 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
729 | return print_infinite_recursion_bug(); |
730 | ||
731 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
732 | if (source->usage_mask & (1 << find_usage_bit)) { | |
733 | backwards_match = source; | |
734 | return 2; | |
735 | } | |
736 | ||
737 | /* | |
738 | * Check this lock's dependency list: | |
739 | */ | |
740 | list_for_each_entry(entry, &source->locks_before, entry) { | |
741 | debug_atomic_inc(&nr_find_usage_backwards_recursions); | |
742 | ret = find_usage_backwards(entry->class, depth+1); | |
743 | if (ret == 2 || ret == 0) | |
744 | return ret; | |
745 | } | |
746 | return 1; | |
747 | } | |
748 | ||
749 | static int | |
750 | print_bad_irq_dependency(struct task_struct *curr, | |
751 | struct held_lock *prev, | |
752 | struct held_lock *next, | |
753 | enum lock_usage_bit bit1, | |
754 | enum lock_usage_bit bit2, | |
755 | const char *irqclass) | |
756 | { | |
74c383f1 | 757 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
758 | return 0; |
759 | ||
760 | printk("\n======================================================\n"); | |
761 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
762 | irqclass, irqclass); | |
99de055a | 763 | print_kernel_version(); |
fbb9ce95 IM |
764 | printk( "------------------------------------------------------\n"); |
765 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
766 | curr->comm, curr->pid, | |
767 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, | |
768 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
769 | curr->hardirqs_enabled, | |
770 | curr->softirqs_enabled); | |
771 | print_lock(next); | |
772 | ||
773 | printk("\nand this task is already holding:\n"); | |
774 | print_lock(prev); | |
775 | printk("which would create a new lock dependency:\n"); | |
776 | print_lock_name(prev->class); | |
777 | printk(" ->"); | |
778 | print_lock_name(next->class); | |
779 | printk("\n"); | |
780 | ||
781 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
782 | irqclass); | |
783 | print_lock_name(backwards_match); | |
784 | printk("\n... which became %s-irq-safe at:\n", irqclass); | |
785 | ||
786 | print_stack_trace(backwards_match->usage_traces + bit1, 1); | |
787 | ||
788 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
789 | print_lock_name(forwards_match); | |
790 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); | |
791 | printk("..."); | |
792 | ||
793 | print_stack_trace(forwards_match->usage_traces + bit2, 1); | |
794 | ||
795 | printk("\nother info that might help us debug this:\n\n"); | |
796 | lockdep_print_held_locks(curr); | |
797 | ||
798 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); | |
799 | print_lock_dependencies(backwards_match, 0); | |
800 | ||
801 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); | |
802 | print_lock_dependencies(forwards_match, 0); | |
803 | ||
804 | printk("\nstack backtrace:\n"); | |
805 | dump_stack(); | |
806 | ||
807 | return 0; | |
808 | } | |
809 | ||
810 | static int | |
811 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
812 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
813 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
814 | { | |
815 | int ret; | |
816 | ||
817 | find_usage_bit = bit_backwards; | |
818 | /* fills in <backwards_match> */ | |
819 | ret = find_usage_backwards(prev->class, 0); | |
820 | if (!ret || ret == 1) | |
821 | return ret; | |
822 | ||
823 | find_usage_bit = bit_forwards; | |
824 | ret = find_usage_forwards(next->class, 0); | |
825 | if (!ret || ret == 1) | |
826 | return ret; | |
827 | /* ret == 2 */ | |
828 | return print_bad_irq_dependency(curr, prev, next, | |
829 | bit_backwards, bit_forwards, irqclass); | |
830 | } | |
831 | ||
832 | #endif | |
833 | ||
ca58abcb | 834 | #ifdef CONFIG_PROVE_LOCKING |
fbb9ce95 IM |
835 | static int |
836 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
837 | struct held_lock *next) | |
838 | { | |
74c383f1 | 839 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
840 | return 0; |
841 | ||
842 | printk("\n=============================================\n"); | |
843 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 844 | print_kernel_version(); |
fbb9ce95 IM |
845 | printk( "---------------------------------------------\n"); |
846 | printk("%s/%d is trying to acquire lock:\n", | |
847 | curr->comm, curr->pid); | |
848 | print_lock(next); | |
849 | printk("\nbut task is already holding lock:\n"); | |
850 | print_lock(prev); | |
851 | ||
852 | printk("\nother info that might help us debug this:\n"); | |
853 | lockdep_print_held_locks(curr); | |
854 | ||
855 | printk("\nstack backtrace:\n"); | |
856 | dump_stack(); | |
857 | ||
858 | return 0; | |
859 | } | |
860 | ||
861 | /* | |
862 | * Check whether we are holding such a class already. | |
863 | * | |
864 | * (Note that this has to be done separately, because the graph cannot | |
865 | * detect such classes of deadlocks.) | |
866 | * | |
867 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
868 | */ | |
869 | static int | |
870 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
871 | struct lockdep_map *next_instance, int read) | |
872 | { | |
873 | struct held_lock *prev; | |
874 | int i; | |
875 | ||
876 | for (i = 0; i < curr->lockdep_depth; i++) { | |
877 | prev = curr->held_locks + i; | |
878 | if (prev->class != next->class) | |
879 | continue; | |
880 | /* | |
881 | * Allow read-after-read recursion of the same | |
6c9076ec | 882 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 883 | */ |
6c9076ec | 884 | if ((read == 2) && prev->read) |
fbb9ce95 IM |
885 | return 2; |
886 | return print_deadlock_bug(curr, prev, next); | |
887 | } | |
888 | return 1; | |
889 | } | |
890 | ||
891 | /* | |
892 | * There was a chain-cache miss, and we are about to add a new dependency | |
893 | * to a previous lock. We recursively validate the following rules: | |
894 | * | |
895 | * - would the adding of the <prev> -> <next> dependency create a | |
896 | * circular dependency in the graph? [== circular deadlock] | |
897 | * | |
898 | * - does the new prev->next dependency connect any hardirq-safe lock | |
899 | * (in the full backwards-subgraph starting at <prev>) with any | |
900 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
901 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
902 | * | |
903 | * - does the new prev->next dependency connect any softirq-safe lock | |
904 | * (in the full backwards-subgraph starting at <prev>) with any | |
905 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
906 | * <next>)? [== illegal lock inversion with softirq contexts] | |
907 | * | |
908 | * any of these scenarios could lead to a deadlock. | |
909 | * | |
910 | * Then if all the validations pass, we add the forwards and backwards | |
911 | * dependency. | |
912 | */ | |
913 | static int | |
914 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 915 | struct held_lock *next, int distance) |
fbb9ce95 IM |
916 | { |
917 | struct lock_list *entry; | |
918 | int ret; | |
919 | ||
920 | /* | |
921 | * Prove that the new <prev> -> <next> dependency would not | |
922 | * create a circular dependency in the graph. (We do this by | |
923 | * forward-recursing into the graph starting at <next>, and | |
924 | * checking whether we can reach <prev>.) | |
925 | * | |
926 | * We are using global variables to control the recursion, to | |
927 | * keep the stackframe size of the recursive functions low: | |
928 | */ | |
929 | check_source = next; | |
930 | check_target = prev; | |
931 | if (!(check_noncircular(next->class, 0))) | |
932 | return print_circular_bug_tail(); | |
933 | ||
934 | #ifdef CONFIG_TRACE_IRQFLAGS | |
935 | /* | |
936 | * Prove that the new dependency does not connect a hardirq-safe | |
937 | * lock with a hardirq-unsafe lock - to achieve this we search | |
938 | * the backwards-subgraph starting at <prev>, and the | |
939 | * forwards-subgraph starting at <next>: | |
940 | */ | |
941 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, | |
942 | LOCK_ENABLED_HARDIRQS, "hard")) | |
943 | return 0; | |
944 | ||
945 | /* | |
946 | * Prove that the new dependency does not connect a hardirq-safe-read | |
947 | * lock with a hardirq-unsafe lock - to achieve this we search | |
948 | * the backwards-subgraph starting at <prev>, and the | |
949 | * forwards-subgraph starting at <next>: | |
950 | */ | |
951 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, | |
952 | LOCK_ENABLED_HARDIRQS, "hard-read")) | |
953 | return 0; | |
954 | ||
955 | /* | |
956 | * Prove that the new dependency does not connect a softirq-safe | |
957 | * lock with a softirq-unsafe lock - to achieve this we search | |
958 | * the backwards-subgraph starting at <prev>, and the | |
959 | * forwards-subgraph starting at <next>: | |
960 | */ | |
961 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, | |
962 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
963 | return 0; | |
964 | /* | |
965 | * Prove that the new dependency does not connect a softirq-safe-read | |
966 | * lock with a softirq-unsafe lock - to achieve this we search | |
967 | * the backwards-subgraph starting at <prev>, and the | |
968 | * forwards-subgraph starting at <next>: | |
969 | */ | |
970 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, | |
971 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
972 | return 0; | |
973 | #endif | |
974 | /* | |
975 | * For recursive read-locks we do all the dependency checks, | |
976 | * but we dont store read-triggered dependencies (only | |
977 | * write-triggered dependencies). This ensures that only the | |
978 | * write-side dependencies matter, and that if for example a | |
979 | * write-lock never takes any other locks, then the reads are | |
980 | * equivalent to a NOP. | |
981 | */ | |
982 | if (next->read == 2 || prev->read == 2) | |
983 | return 1; | |
984 | /* | |
985 | * Is the <prev> -> <next> dependency already present? | |
986 | * | |
987 | * (this may occur even though this is a new chain: consider | |
988 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
989 | * chains - the second one will be new, but L1 already has | |
990 | * L2 added to its dependency list, due to the first chain.) | |
991 | */ | |
992 | list_for_each_entry(entry, &prev->class->locks_after, entry) { | |
068135e6 JB |
993 | if (entry->class == next->class) { |
994 | if (distance == 1) | |
995 | entry->distance = 1; | |
fbb9ce95 | 996 | return 2; |
068135e6 | 997 | } |
fbb9ce95 IM |
998 | } |
999 | ||
1000 | /* | |
1001 | * Ok, all validations passed, add the new lock | |
1002 | * to the previous lock's dependency list: | |
1003 | */ | |
1004 | ret = add_lock_to_list(prev->class, next->class, | |
068135e6 JB |
1005 | &prev->class->locks_after, next->acquire_ip, distance); |
1006 | ||
fbb9ce95 IM |
1007 | if (!ret) |
1008 | return 0; | |
910b1b2e | 1009 | |
fbb9ce95 | 1010 | ret = add_lock_to_list(next->class, prev->class, |
068135e6 | 1011 | &next->class->locks_before, next->acquire_ip, distance); |
910b1b2e JP |
1012 | if (!ret) |
1013 | return 0; | |
fbb9ce95 IM |
1014 | |
1015 | /* | |
1016 | * Debugging printouts: | |
1017 | */ | |
1018 | if (verbose(prev->class) || verbose(next->class)) { | |
74c383f1 | 1019 | graph_unlock(); |
fbb9ce95 IM |
1020 | printk("\n new dependency: "); |
1021 | print_lock_name(prev->class); | |
1022 | printk(" => "); | |
1023 | print_lock_name(next->class); | |
1024 | printk("\n"); | |
1025 | dump_stack(); | |
74c383f1 | 1026 | return graph_lock(); |
fbb9ce95 IM |
1027 | } |
1028 | return 1; | |
1029 | } | |
1030 | ||
1031 | /* | |
1032 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1033 | * The ones that are relevant are (in increasing distance from curr): | |
1034 | * all consecutive trylock entries and the final non-trylock entry - or | |
1035 | * the end of this context's lock-chain - whichever comes first. | |
1036 | */ | |
1037 | static int | |
1038 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1039 | { | |
1040 | int depth = curr->lockdep_depth; | |
1041 | struct held_lock *hlock; | |
1042 | ||
1043 | /* | |
1044 | * Debugging checks. | |
1045 | * | |
1046 | * Depth must not be zero for a non-head lock: | |
1047 | */ | |
1048 | if (!depth) | |
1049 | goto out_bug; | |
1050 | /* | |
1051 | * At least two relevant locks must exist for this | |
1052 | * to be a head: | |
1053 | */ | |
1054 | if (curr->held_locks[depth].irq_context != | |
1055 | curr->held_locks[depth-1].irq_context) | |
1056 | goto out_bug; | |
1057 | ||
1058 | for (;;) { | |
068135e6 | 1059 | int distance = curr->lockdep_depth - depth + 1; |
fbb9ce95 IM |
1060 | hlock = curr->held_locks + depth-1; |
1061 | /* | |
1062 | * Only non-recursive-read entries get new dependencies | |
1063 | * added: | |
1064 | */ | |
1065 | if (hlock->read != 2) { | |
068135e6 | 1066 | if (!check_prev_add(curr, hlock, next, distance)) |
910b1b2e | 1067 | return 0; |
fbb9ce95 IM |
1068 | /* |
1069 | * Stop after the first non-trylock entry, | |
1070 | * as non-trylock entries have added their | |
1071 | * own direct dependencies already, so this | |
1072 | * lock is connected to them indirectly: | |
1073 | */ | |
1074 | if (!hlock->trylock) | |
1075 | break; | |
1076 | } | |
1077 | depth--; | |
1078 | /* | |
1079 | * End of lock-stack? | |
1080 | */ | |
1081 | if (!depth) | |
1082 | break; | |
1083 | /* | |
1084 | * Stop the search if we cross into another context: | |
1085 | */ | |
1086 | if (curr->held_locks[depth].irq_context != | |
1087 | curr->held_locks[depth-1].irq_context) | |
1088 | break; | |
1089 | } | |
1090 | return 1; | |
1091 | out_bug: | |
74c383f1 IM |
1092 | if (!debug_locks_off_graph_unlock()) |
1093 | return 0; | |
1094 | ||
1095 | WARN_ON(1); | |
fbb9ce95 IM |
1096 | |
1097 | return 0; | |
1098 | } | |
ca58abcb | 1099 | #endif |
fbb9ce95 IM |
1100 | |
1101 | /* | |
1102 | * Is this the address of a static object: | |
1103 | */ | |
1104 | static int static_obj(void *obj) | |
1105 | { | |
1106 | unsigned long start = (unsigned long) &_stext, | |
1107 | end = (unsigned long) &_end, | |
1108 | addr = (unsigned long) obj; | |
1109 | #ifdef CONFIG_SMP | |
1110 | int i; | |
1111 | #endif | |
1112 | ||
1113 | /* | |
1114 | * static variable? | |
1115 | */ | |
1116 | if ((addr >= start) && (addr < end)) | |
1117 | return 1; | |
1118 | ||
1119 | #ifdef CONFIG_SMP | |
1120 | /* | |
1121 | * percpu var? | |
1122 | */ | |
1123 | for_each_possible_cpu(i) { | |
1124 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
1ff56830 IM |
1125 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM |
1126 | + per_cpu_offset(i); | |
fbb9ce95 IM |
1127 | |
1128 | if ((addr >= start) && (addr < end)) | |
1129 | return 1; | |
1130 | } | |
1131 | #endif | |
1132 | ||
1133 | /* | |
1134 | * module var? | |
1135 | */ | |
1136 | return is_module_address(addr); | |
1137 | } | |
1138 | ||
1139 | /* | |
1140 | * To make lock name printouts unique, we calculate a unique | |
1141 | * class->name_version generation counter: | |
1142 | */ | |
1143 | static int count_matching_names(struct lock_class *new_class) | |
1144 | { | |
1145 | struct lock_class *class; | |
1146 | int count = 0; | |
1147 | ||
1148 | if (!new_class->name) | |
1149 | return 0; | |
1150 | ||
1151 | list_for_each_entry(class, &all_lock_classes, lock_entry) { | |
1152 | if (new_class->key - new_class->subclass == class->key) | |
1153 | return class->name_version; | |
1154 | if (class->name && !strcmp(class->name, new_class->name)) | |
1155 | count = max(count, class->name_version); | |
1156 | } | |
1157 | ||
1158 | return count + 1; | |
1159 | } | |
1160 | ||
fbb9ce95 IM |
1161 | /* |
1162 | * Register a lock's class in the hash-table, if the class is not present | |
1163 | * yet. Otherwise we look it up. We cache the result in the lock object | |
1164 | * itself, so actual lookup of the hash should be once per lock object. | |
1165 | */ | |
1166 | static inline struct lock_class * | |
d6d897ce | 1167 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) |
fbb9ce95 IM |
1168 | { |
1169 | struct lockdep_subclass_key *key; | |
1170 | struct list_head *hash_head; | |
1171 | struct lock_class *class; | |
1172 | ||
1173 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1174 | /* | |
1175 | * If the architecture calls into lockdep before initializing | |
1176 | * the hashes then we'll warn about it later. (we cannot printk | |
1177 | * right now) | |
1178 | */ | |
1179 | if (unlikely(!lockdep_initialized)) { | |
1180 | lockdep_init(); | |
1181 | lockdep_init_error = 1; | |
1182 | } | |
1183 | #endif | |
1184 | ||
1185 | /* | |
1186 | * Static locks do not have their class-keys yet - for them the key | |
1187 | * is the lock object itself: | |
1188 | */ | |
1189 | if (unlikely(!lock->key)) | |
1190 | lock->key = (void *)lock; | |
1191 | ||
1192 | /* | |
1193 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
1194 | * lock_class_key variable is passed in through the mutex_init() | |
1195 | * (or spin_lock_init()) call - which acts as the key. For static | |
1196 | * locks we use the lock object itself as the key. | |
1197 | */ | |
3dc3099a | 1198 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class)); |
fbb9ce95 IM |
1199 | |
1200 | key = lock->key->subkeys + subclass; | |
1201 | ||
1202 | hash_head = classhashentry(key); | |
1203 | ||
1204 | /* | |
1205 | * We can walk the hash lockfree, because the hash only | |
1206 | * grows, and we are careful when adding entries to the end: | |
1207 | */ | |
1208 | list_for_each_entry(class, hash_head, hash_entry) | |
1209 | if (class->key == key) | |
d6d897ce IM |
1210 | return class; |
1211 | ||
1212 | return NULL; | |
1213 | } | |
1214 | ||
1215 | /* | |
1216 | * Register a lock's class in the hash-table, if the class is not present | |
1217 | * yet. Otherwise we look it up. We cache the result in the lock object | |
1218 | * itself, so actual lookup of the hash should be once per lock object. | |
1219 | */ | |
1220 | static inline struct lock_class * | |
4dfbb9d8 | 1221 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
d6d897ce IM |
1222 | { |
1223 | struct lockdep_subclass_key *key; | |
1224 | struct list_head *hash_head; | |
1225 | struct lock_class *class; | |
70e45067 | 1226 | unsigned long flags; |
d6d897ce IM |
1227 | |
1228 | class = look_up_lock_class(lock, subclass); | |
1229 | if (likely(class)) | |
1230 | return class; | |
fbb9ce95 IM |
1231 | |
1232 | /* | |
1233 | * Debug-check: all keys must be persistent! | |
1234 | */ | |
1235 | if (!static_obj(lock->key)) { | |
1236 | debug_locks_off(); | |
1237 | printk("INFO: trying to register non-static key.\n"); | |
1238 | printk("the code is fine but needs lockdep annotation.\n"); | |
1239 | printk("turning off the locking correctness validator.\n"); | |
1240 | dump_stack(); | |
1241 | ||
1242 | return NULL; | |
1243 | } | |
1244 | ||
d6d897ce IM |
1245 | key = lock->key->subkeys + subclass; |
1246 | hash_head = classhashentry(key); | |
1247 | ||
70e45067 | 1248 | raw_local_irq_save(flags); |
74c383f1 IM |
1249 | if (!graph_lock()) { |
1250 | raw_local_irq_restore(flags); | |
1251 | return NULL; | |
1252 | } | |
fbb9ce95 IM |
1253 | /* |
1254 | * We have to do the hash-walk again, to avoid races | |
1255 | * with another CPU: | |
1256 | */ | |
1257 | list_for_each_entry(class, hash_head, hash_entry) | |
1258 | if (class->key == key) | |
1259 | goto out_unlock_set; | |
1260 | /* | |
1261 | * Allocate a new key from the static array, and add it to | |
1262 | * the hash: | |
1263 | */ | |
1264 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
74c383f1 IM |
1265 | if (!debug_locks_off_graph_unlock()) { |
1266 | raw_local_irq_restore(flags); | |
1267 | return NULL; | |
1268 | } | |
70e45067 | 1269 | raw_local_irq_restore(flags); |
74c383f1 | 1270 | |
fbb9ce95 IM |
1271 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); |
1272 | printk("turning off the locking correctness validator.\n"); | |
1273 | return NULL; | |
1274 | } | |
1275 | class = lock_classes + nr_lock_classes++; | |
1276 | debug_atomic_inc(&nr_unused_locks); | |
1277 | class->key = key; | |
1278 | class->name = lock->name; | |
1279 | class->subclass = subclass; | |
1280 | INIT_LIST_HEAD(&class->lock_entry); | |
1281 | INIT_LIST_HEAD(&class->locks_before); | |
1282 | INIT_LIST_HEAD(&class->locks_after); | |
1283 | class->name_version = count_matching_names(class); | |
1284 | /* | |
1285 | * We use RCU's safe list-add method to make | |
1286 | * parallel walking of the hash-list safe: | |
1287 | */ | |
1288 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1289 | ||
1290 | if (verbose(class)) { | |
74c383f1 | 1291 | graph_unlock(); |
70e45067 | 1292 | raw_local_irq_restore(flags); |
74c383f1 | 1293 | |
fbb9ce95 IM |
1294 | printk("\nnew class %p: %s", class->key, class->name); |
1295 | if (class->name_version > 1) | |
1296 | printk("#%d", class->name_version); | |
1297 | printk("\n"); | |
1298 | dump_stack(); | |
74c383f1 | 1299 | |
70e45067 | 1300 | raw_local_irq_save(flags); |
74c383f1 IM |
1301 | if (!graph_lock()) { |
1302 | raw_local_irq_restore(flags); | |
1303 | return NULL; | |
1304 | } | |
fbb9ce95 IM |
1305 | } |
1306 | out_unlock_set: | |
74c383f1 | 1307 | graph_unlock(); |
70e45067 | 1308 | raw_local_irq_restore(flags); |
fbb9ce95 | 1309 | |
4dfbb9d8 | 1310 | if (!subclass || force) |
d6d897ce | 1311 | lock->class_cache = class; |
fbb9ce95 | 1312 | |
381a2292 JP |
1313 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
1314 | return NULL; | |
fbb9ce95 IM |
1315 | |
1316 | return class; | |
1317 | } | |
1318 | ||
ca58abcb | 1319 | #ifdef CONFIG_PROVE_LOCKING |
fbb9ce95 IM |
1320 | /* |
1321 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1322 | * add it and return 1 - in this case the new dependency chain is |
1323 | * validated. If the key is already hashed, return 0. | |
1324 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1325 | */ |
81fc685a | 1326 | static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class) |
fbb9ce95 IM |
1327 | { |
1328 | struct list_head *hash_head = chainhashentry(chain_key); | |
1329 | struct lock_chain *chain; | |
1330 | ||
381a2292 JP |
1331 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1332 | return 0; | |
fbb9ce95 IM |
1333 | /* |
1334 | * We can walk it lock-free, because entries only get added | |
1335 | * to the hash: | |
1336 | */ | |
1337 | list_for_each_entry(chain, hash_head, entry) { | |
1338 | if (chain->chain_key == chain_key) { | |
1339 | cache_hit: | |
1340 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1341 | if (very_verbose(class)) |
755cd900 AM |
1342 | printk("\nhash chain already cached, key: " |
1343 | "%016Lx tail class: [%p] %s\n", | |
1344 | (unsigned long long)chain_key, | |
1345 | class->key, class->name); | |
fbb9ce95 IM |
1346 | return 0; |
1347 | } | |
1348 | } | |
81fc685a | 1349 | if (very_verbose(class)) |
755cd900 AM |
1350 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1351 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1352 | /* |
1353 | * Allocate a new chain entry from the static array, and add | |
1354 | * it to the hash: | |
1355 | */ | |
74c383f1 IM |
1356 | if (!graph_lock()) |
1357 | return 0; | |
fbb9ce95 IM |
1358 | /* |
1359 | * We have to walk the chain again locked - to avoid duplicates: | |
1360 | */ | |
1361 | list_for_each_entry(chain, hash_head, entry) { | |
1362 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1363 | graph_unlock(); |
fbb9ce95 IM |
1364 | goto cache_hit; |
1365 | } | |
1366 | } | |
1367 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1368 | if (!debug_locks_off_graph_unlock()) |
1369 | return 0; | |
1370 | ||
fbb9ce95 IM |
1371 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1372 | printk("turning off the locking correctness validator.\n"); | |
1373 | return 0; | |
1374 | } | |
1375 | chain = lock_chains + nr_lock_chains++; | |
1376 | chain->chain_key = chain_key; | |
1377 | list_add_tail_rcu(&chain->entry, hash_head); | |
1378 | debug_atomic_inc(&chain_lookup_misses); | |
1379 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1380 | if (current->hardirq_context) | |
1381 | nr_hardirq_chains++; | |
1382 | else { | |
1383 | if (current->softirq_context) | |
1384 | nr_softirq_chains++; | |
1385 | else | |
1386 | nr_process_chains++; | |
1387 | } | |
1388 | #else | |
1389 | nr_process_chains++; | |
1390 | #endif | |
1391 | ||
1392 | return 1; | |
1393 | } | |
ca58abcb | 1394 | #endif |
fbb9ce95 IM |
1395 | |
1396 | /* | |
1397 | * We are building curr_chain_key incrementally, so double-check | |
1398 | * it from scratch, to make sure that it's done correctly: | |
1399 | */ | |
1400 | static void check_chain_key(struct task_struct *curr) | |
1401 | { | |
1402 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1403 | struct held_lock *hlock, *prev_hlock = NULL; | |
1404 | unsigned int i, id; | |
1405 | u64 chain_key = 0; | |
1406 | ||
1407 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1408 | hlock = curr->held_locks + i; | |
1409 | if (chain_key != hlock->prev_chain_key) { | |
1410 | debug_locks_off(); | |
1411 | printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n", | |
1412 | curr->lockdep_depth, i, | |
1413 | (unsigned long long)chain_key, | |
1414 | (unsigned long long)hlock->prev_chain_key); | |
1415 | WARN_ON(1); | |
1416 | return; | |
1417 | } | |
1418 | id = hlock->class - lock_classes; | |
381a2292 JP |
1419 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1420 | return; | |
1421 | ||
fbb9ce95 IM |
1422 | if (prev_hlock && (prev_hlock->irq_context != |
1423 | hlock->irq_context)) | |
1424 | chain_key = 0; | |
1425 | chain_key = iterate_chain_key(chain_key, id); | |
1426 | prev_hlock = hlock; | |
1427 | } | |
1428 | if (chain_key != curr->curr_chain_key) { | |
1429 | debug_locks_off(); | |
1430 | printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n", | |
1431 | curr->lockdep_depth, i, | |
1432 | (unsigned long long)chain_key, | |
1433 | (unsigned long long)curr->curr_chain_key); | |
1434 | WARN_ON(1); | |
1435 | } | |
1436 | #endif | |
1437 | } | |
1438 | ||
1439 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1440 | ||
1441 | /* | |
1442 | * print irq inversion bug: | |
1443 | */ | |
1444 | static int | |
1445 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, | |
1446 | struct held_lock *this, int forwards, | |
1447 | const char *irqclass) | |
1448 | { | |
74c383f1 | 1449 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1450 | return 0; |
1451 | ||
1452 | printk("\n=========================================================\n"); | |
1453 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 1454 | print_kernel_version(); |
fbb9ce95 IM |
1455 | printk( "---------------------------------------------------------\n"); |
1456 | printk("%s/%d just changed the state of lock:\n", | |
1457 | curr->comm, curr->pid); | |
1458 | print_lock(this); | |
1459 | if (forwards) | |
1460 | printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass); | |
1461 | else | |
1462 | printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass); | |
1463 | print_lock_name(other); | |
1464 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); | |
1465 | ||
1466 | printk("\nother info that might help us debug this:\n"); | |
1467 | lockdep_print_held_locks(curr); | |
1468 | ||
1469 | printk("\nthe first lock's dependencies:\n"); | |
1470 | print_lock_dependencies(this->class, 0); | |
1471 | ||
1472 | printk("\nthe second lock's dependencies:\n"); | |
1473 | print_lock_dependencies(other, 0); | |
1474 | ||
1475 | printk("\nstack backtrace:\n"); | |
1476 | dump_stack(); | |
1477 | ||
1478 | return 0; | |
1479 | } | |
1480 | ||
1481 | /* | |
1482 | * Prove that in the forwards-direction subgraph starting at <this> | |
1483 | * there is no lock matching <mask>: | |
1484 | */ | |
1485 | static int | |
1486 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
1487 | enum lock_usage_bit bit, const char *irqclass) | |
1488 | { | |
1489 | int ret; | |
1490 | ||
1491 | find_usage_bit = bit; | |
1492 | /* fills in <forwards_match> */ | |
1493 | ret = find_usage_forwards(this->class, 0); | |
1494 | if (!ret || ret == 1) | |
1495 | return ret; | |
1496 | ||
1497 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); | |
1498 | } | |
1499 | ||
1500 | /* | |
1501 | * Prove that in the backwards-direction subgraph starting at <this> | |
1502 | * there is no lock matching <mask>: | |
1503 | */ | |
1504 | static int | |
1505 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
1506 | enum lock_usage_bit bit, const char *irqclass) | |
1507 | { | |
1508 | int ret; | |
1509 | ||
1510 | find_usage_bit = bit; | |
1511 | /* fills in <backwards_match> */ | |
1512 | ret = find_usage_backwards(this->class, 0); | |
1513 | if (!ret || ret == 1) | |
1514 | return ret; | |
1515 | ||
1516 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); | |
1517 | } | |
1518 | ||
3117df04 | 1519 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
1520 | { |
1521 | printk("irq event stamp: %u\n", curr->irq_events); | |
1522 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
1523 | print_ip_sym(curr->hardirq_enable_ip); | |
1524 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
1525 | print_ip_sym(curr->hardirq_disable_ip); | |
1526 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
1527 | print_ip_sym(curr->softirq_enable_ip); | |
1528 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
1529 | print_ip_sym(curr->softirq_disable_ip); | |
1530 | } | |
1531 | ||
fbb9ce95 IM |
1532 | #endif |
1533 | ||
1534 | static int | |
1535 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1536 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1537 | { | |
74c383f1 | 1538 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1539 | return 0; |
1540 | ||
1541 | printk("\n=================================\n"); | |
1542 | printk( "[ INFO: inconsistent lock state ]\n"); | |
99de055a | 1543 | print_kernel_version(); |
fbb9ce95 IM |
1544 | printk( "---------------------------------\n"); |
1545 | ||
1546 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1547 | usage_str[prev_bit], usage_str[new_bit]); | |
1548 | ||
1549 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
1550 | curr->comm, curr->pid, | |
1551 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, | |
1552 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1553 | trace_hardirqs_enabled(curr), | |
1554 | trace_softirqs_enabled(curr)); | |
1555 | print_lock(this); | |
1556 | ||
1557 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
1558 | print_stack_trace(this->class->usage_traces + prev_bit, 1); | |
1559 | ||
1560 | print_irqtrace_events(curr); | |
1561 | printk("\nother info that might help us debug this:\n"); | |
1562 | lockdep_print_held_locks(curr); | |
1563 | ||
1564 | printk("\nstack backtrace:\n"); | |
1565 | dump_stack(); | |
1566 | ||
1567 | return 0; | |
1568 | } | |
1569 | ||
1570 | /* | |
1571 | * Print out an error if an invalid bit is set: | |
1572 | */ | |
1573 | static inline int | |
1574 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1575 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1576 | { | |
1577 | if (unlikely(this->class->usage_mask & (1 << bad_bit))) | |
1578 | return print_usage_bug(curr, this, bad_bit, new_bit); | |
1579 | return 1; | |
1580 | } | |
1581 | ||
1582 | #define STRICT_READ_CHECKS 1 | |
1583 | ||
1584 | /* | |
1585 | * Mark a lock with a usage bit, and validate the state transition: | |
1586 | */ | |
1587 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
4ff773bb | 1588 | enum lock_usage_bit new_bit) |
fbb9ce95 IM |
1589 | { |
1590 | unsigned int new_mask = 1 << new_bit, ret = 1; | |
1591 | ||
1592 | /* | |
1593 | * If already set then do not dirty the cacheline, | |
1594 | * nor do any checks: | |
1595 | */ | |
1596 | if (likely(this->class->usage_mask & new_mask)) | |
1597 | return 1; | |
1598 | ||
74c383f1 IM |
1599 | if (!graph_lock()) |
1600 | return 0; | |
fbb9ce95 IM |
1601 | /* |
1602 | * Make sure we didnt race: | |
1603 | */ | |
1604 | if (unlikely(this->class->usage_mask & new_mask)) { | |
74c383f1 | 1605 | graph_unlock(); |
fbb9ce95 IM |
1606 | return 1; |
1607 | } | |
1608 | ||
1609 | this->class->usage_mask |= new_mask; | |
1610 | ||
fbb9ce95 IM |
1611 | if (!save_trace(this->class->usage_traces + new_bit)) |
1612 | return 0; | |
1613 | ||
1614 | switch (new_bit) { | |
1615 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1616 | case LOCK_USED_IN_HARDIRQ: | |
1617 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1618 | return 0; | |
1619 | if (!valid_state(curr, this, new_bit, | |
1620 | LOCK_ENABLED_HARDIRQS_READ)) | |
1621 | return 0; | |
1622 | /* | |
1623 | * just marked it hardirq-safe, check that this lock | |
1624 | * took no hardirq-unsafe lock in the past: | |
1625 | */ | |
1626 | if (!check_usage_forwards(curr, this, | |
1627 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1628 | return 0; | |
1629 | #if STRICT_READ_CHECKS | |
1630 | /* | |
1631 | * just marked it hardirq-safe, check that this lock | |
1632 | * took no hardirq-unsafe-read lock in the past: | |
1633 | */ | |
1634 | if (!check_usage_forwards(curr, this, | |
1635 | LOCK_ENABLED_HARDIRQS_READ, "hard-read")) | |
1636 | return 0; | |
1637 | #endif | |
1638 | if (hardirq_verbose(this->class)) | |
1639 | ret = 2; | |
1640 | break; | |
1641 | case LOCK_USED_IN_SOFTIRQ: | |
1642 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1643 | return 0; | |
1644 | if (!valid_state(curr, this, new_bit, | |
1645 | LOCK_ENABLED_SOFTIRQS_READ)) | |
1646 | return 0; | |
1647 | /* | |
1648 | * just marked it softirq-safe, check that this lock | |
1649 | * took no softirq-unsafe lock in the past: | |
1650 | */ | |
1651 | if (!check_usage_forwards(curr, this, | |
1652 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1653 | return 0; | |
1654 | #if STRICT_READ_CHECKS | |
1655 | /* | |
1656 | * just marked it softirq-safe, check that this lock | |
1657 | * took no softirq-unsafe-read lock in the past: | |
1658 | */ | |
1659 | if (!check_usage_forwards(curr, this, | |
1660 | LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) | |
1661 | return 0; | |
1662 | #endif | |
1663 | if (softirq_verbose(this->class)) | |
1664 | ret = 2; | |
1665 | break; | |
1666 | case LOCK_USED_IN_HARDIRQ_READ: | |
1667 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1668 | return 0; | |
1669 | /* | |
1670 | * just marked it hardirq-read-safe, check that this lock | |
1671 | * took no hardirq-unsafe lock in the past: | |
1672 | */ | |
1673 | if (!check_usage_forwards(curr, this, | |
1674 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1675 | return 0; | |
1676 | if (hardirq_verbose(this->class)) | |
1677 | ret = 2; | |
1678 | break; | |
1679 | case LOCK_USED_IN_SOFTIRQ_READ: | |
1680 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1681 | return 0; | |
1682 | /* | |
1683 | * just marked it softirq-read-safe, check that this lock | |
1684 | * took no softirq-unsafe lock in the past: | |
1685 | */ | |
1686 | if (!check_usage_forwards(curr, this, | |
1687 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1688 | return 0; | |
1689 | if (softirq_verbose(this->class)) | |
1690 | ret = 2; | |
1691 | break; | |
1692 | case LOCK_ENABLED_HARDIRQS: | |
1693 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
1694 | return 0; | |
1695 | if (!valid_state(curr, this, new_bit, | |
1696 | LOCK_USED_IN_HARDIRQ_READ)) | |
1697 | return 0; | |
1698 | /* | |
1699 | * just marked it hardirq-unsafe, check that no hardirq-safe | |
1700 | * lock in the system ever took it in the past: | |
1701 | */ | |
1702 | if (!check_usage_backwards(curr, this, | |
1703 | LOCK_USED_IN_HARDIRQ, "hard")) | |
1704 | return 0; | |
1705 | #if STRICT_READ_CHECKS | |
1706 | /* | |
1707 | * just marked it hardirq-unsafe, check that no | |
1708 | * hardirq-safe-read lock in the system ever took | |
1709 | * it in the past: | |
1710 | */ | |
1711 | if (!check_usage_backwards(curr, this, | |
1712 | LOCK_USED_IN_HARDIRQ_READ, "hard-read")) | |
1713 | return 0; | |
1714 | #endif | |
1715 | if (hardirq_verbose(this->class)) | |
1716 | ret = 2; | |
1717 | break; | |
1718 | case LOCK_ENABLED_SOFTIRQS: | |
1719 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
1720 | return 0; | |
1721 | if (!valid_state(curr, this, new_bit, | |
1722 | LOCK_USED_IN_SOFTIRQ_READ)) | |
1723 | return 0; | |
1724 | /* | |
1725 | * just marked it softirq-unsafe, check that no softirq-safe | |
1726 | * lock in the system ever took it in the past: | |
1727 | */ | |
1728 | if (!check_usage_backwards(curr, this, | |
1729 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
1730 | return 0; | |
1731 | #if STRICT_READ_CHECKS | |
1732 | /* | |
1733 | * just marked it softirq-unsafe, check that no | |
1734 | * softirq-safe-read lock in the system ever took | |
1735 | * it in the past: | |
1736 | */ | |
1737 | if (!check_usage_backwards(curr, this, | |
1738 | LOCK_USED_IN_SOFTIRQ_READ, "soft-read")) | |
1739 | return 0; | |
1740 | #endif | |
1741 | if (softirq_verbose(this->class)) | |
1742 | ret = 2; | |
1743 | break; | |
1744 | case LOCK_ENABLED_HARDIRQS_READ: | |
1745 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
1746 | return 0; | |
1747 | #if STRICT_READ_CHECKS | |
1748 | /* | |
1749 | * just marked it hardirq-read-unsafe, check that no | |
1750 | * hardirq-safe lock in the system ever took it in the past: | |
1751 | */ | |
1752 | if (!check_usage_backwards(curr, this, | |
1753 | LOCK_USED_IN_HARDIRQ, "hard")) | |
1754 | return 0; | |
1755 | #endif | |
1756 | if (hardirq_verbose(this->class)) | |
1757 | ret = 2; | |
1758 | break; | |
1759 | case LOCK_ENABLED_SOFTIRQS_READ: | |
1760 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
1761 | return 0; | |
1762 | #if STRICT_READ_CHECKS | |
1763 | /* | |
1764 | * just marked it softirq-read-unsafe, check that no | |
1765 | * softirq-safe lock in the system ever took it in the past: | |
1766 | */ | |
1767 | if (!check_usage_backwards(curr, this, | |
1768 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
1769 | return 0; | |
1770 | #endif | |
1771 | if (softirq_verbose(this->class)) | |
1772 | ret = 2; | |
1773 | break; | |
1774 | #endif | |
1775 | case LOCK_USED: | |
1776 | /* | |
1777 | * Add it to the global list of classes: | |
1778 | */ | |
1779 | list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes); | |
1780 | debug_atomic_dec(&nr_unused_locks); | |
1781 | break; | |
1782 | default: | |
74c383f1 IM |
1783 | if (!debug_locks_off_graph_unlock()) |
1784 | return 0; | |
fbb9ce95 IM |
1785 | WARN_ON(1); |
1786 | return 0; | |
1787 | } | |
1788 | ||
74c383f1 | 1789 | graph_unlock(); |
fbb9ce95 IM |
1790 | |
1791 | /* | |
74c383f1 | 1792 | * We must printk outside of the graph_lock: |
fbb9ce95 IM |
1793 | */ |
1794 | if (ret == 2) { | |
1795 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
1796 | print_lock(this); | |
1797 | print_irqtrace_events(curr); | |
1798 | dump_stack(); | |
1799 | } | |
1800 | ||
1801 | return ret; | |
1802 | } | |
1803 | ||
1804 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1805 | /* | |
1806 | * Mark all held locks with a usage bit: | |
1807 | */ | |
1808 | static int | |
4ff773bb | 1809 | mark_held_locks(struct task_struct *curr, int hardirq) |
fbb9ce95 IM |
1810 | { |
1811 | enum lock_usage_bit usage_bit; | |
1812 | struct held_lock *hlock; | |
1813 | int i; | |
1814 | ||
1815 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1816 | hlock = curr->held_locks + i; | |
1817 | ||
1818 | if (hardirq) { | |
1819 | if (hlock->read) | |
1820 | usage_bit = LOCK_ENABLED_HARDIRQS_READ; | |
1821 | else | |
1822 | usage_bit = LOCK_ENABLED_HARDIRQS; | |
1823 | } else { | |
1824 | if (hlock->read) | |
1825 | usage_bit = LOCK_ENABLED_SOFTIRQS_READ; | |
1826 | else | |
1827 | usage_bit = LOCK_ENABLED_SOFTIRQS; | |
1828 | } | |
4ff773bb | 1829 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
1830 | return 0; |
1831 | } | |
1832 | ||
1833 | return 1; | |
1834 | } | |
1835 | ||
1836 | /* | |
1837 | * Debugging helper: via this flag we know that we are in | |
1838 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
1839 | */ | |
1840 | static int early_boot_irqs_enabled; | |
1841 | ||
1842 | void early_boot_irqs_off(void) | |
1843 | { | |
1844 | early_boot_irqs_enabled = 0; | |
1845 | } | |
1846 | ||
1847 | void early_boot_irqs_on(void) | |
1848 | { | |
1849 | early_boot_irqs_enabled = 1; | |
1850 | } | |
1851 | ||
1852 | /* | |
1853 | * Hardirqs will be enabled: | |
1854 | */ | |
1855 | void trace_hardirqs_on(void) | |
1856 | { | |
1857 | struct task_struct *curr = current; | |
1858 | unsigned long ip; | |
1859 | ||
1860 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
1861 | return; | |
1862 | ||
1863 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
1864 | return; | |
1865 | ||
1866 | if (unlikely(curr->hardirqs_enabled)) { | |
1867 | debug_atomic_inc(&redundant_hardirqs_on); | |
1868 | return; | |
1869 | } | |
1870 | /* we'll do an OFF -> ON transition: */ | |
1871 | curr->hardirqs_enabled = 1; | |
1872 | ip = (unsigned long) __builtin_return_address(0); | |
1873 | ||
1874 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1875 | return; | |
1876 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
1877 | return; | |
1878 | /* | |
1879 | * We are going to turn hardirqs on, so set the | |
1880 | * usage bit for all held locks: | |
1881 | */ | |
4ff773bb | 1882 | if (!mark_held_locks(curr, 1)) |
fbb9ce95 IM |
1883 | return; |
1884 | /* | |
1885 | * If we have softirqs enabled, then set the usage | |
1886 | * bit for all held locks. (disabled hardirqs prevented | |
1887 | * this bit from being set before) | |
1888 | */ | |
1889 | if (curr->softirqs_enabled) | |
4ff773bb | 1890 | if (!mark_held_locks(curr, 0)) |
fbb9ce95 IM |
1891 | return; |
1892 | ||
1893 | curr->hardirq_enable_ip = ip; | |
1894 | curr->hardirq_enable_event = ++curr->irq_events; | |
1895 | debug_atomic_inc(&hardirqs_on_events); | |
1896 | } | |
1897 | ||
1898 | EXPORT_SYMBOL(trace_hardirqs_on); | |
1899 | ||
1900 | /* | |
1901 | * Hardirqs were disabled: | |
1902 | */ | |
1903 | void trace_hardirqs_off(void) | |
1904 | { | |
1905 | struct task_struct *curr = current; | |
1906 | ||
1907 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
1908 | return; | |
1909 | ||
1910 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1911 | return; | |
1912 | ||
1913 | if (curr->hardirqs_enabled) { | |
1914 | /* | |
1915 | * We have done an ON -> OFF transition: | |
1916 | */ | |
1917 | curr->hardirqs_enabled = 0; | |
1918 | curr->hardirq_disable_ip = _RET_IP_; | |
1919 | curr->hardirq_disable_event = ++curr->irq_events; | |
1920 | debug_atomic_inc(&hardirqs_off_events); | |
1921 | } else | |
1922 | debug_atomic_inc(&redundant_hardirqs_off); | |
1923 | } | |
1924 | ||
1925 | EXPORT_SYMBOL(trace_hardirqs_off); | |
1926 | ||
1927 | /* | |
1928 | * Softirqs will be enabled: | |
1929 | */ | |
1930 | void trace_softirqs_on(unsigned long ip) | |
1931 | { | |
1932 | struct task_struct *curr = current; | |
1933 | ||
1934 | if (unlikely(!debug_locks)) | |
1935 | return; | |
1936 | ||
1937 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1938 | return; | |
1939 | ||
1940 | if (curr->softirqs_enabled) { | |
1941 | debug_atomic_inc(&redundant_softirqs_on); | |
1942 | return; | |
1943 | } | |
1944 | ||
1945 | /* | |
1946 | * We'll do an OFF -> ON transition: | |
1947 | */ | |
1948 | curr->softirqs_enabled = 1; | |
1949 | curr->softirq_enable_ip = ip; | |
1950 | curr->softirq_enable_event = ++curr->irq_events; | |
1951 | debug_atomic_inc(&softirqs_on_events); | |
1952 | /* | |
1953 | * We are going to turn softirqs on, so set the | |
1954 | * usage bit for all held locks, if hardirqs are | |
1955 | * enabled too: | |
1956 | */ | |
1957 | if (curr->hardirqs_enabled) | |
4ff773bb | 1958 | mark_held_locks(curr, 0); |
fbb9ce95 IM |
1959 | } |
1960 | ||
1961 | /* | |
1962 | * Softirqs were disabled: | |
1963 | */ | |
1964 | void trace_softirqs_off(unsigned long ip) | |
1965 | { | |
1966 | struct task_struct *curr = current; | |
1967 | ||
1968 | if (unlikely(!debug_locks)) | |
1969 | return; | |
1970 | ||
1971 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1972 | return; | |
1973 | ||
1974 | if (curr->softirqs_enabled) { | |
1975 | /* | |
1976 | * We have done an ON -> OFF transition: | |
1977 | */ | |
1978 | curr->softirqs_enabled = 0; | |
1979 | curr->softirq_disable_ip = ip; | |
1980 | curr->softirq_disable_event = ++curr->irq_events; | |
1981 | debug_atomic_inc(&softirqs_off_events); | |
1982 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
1983 | } else | |
1984 | debug_atomic_inc(&redundant_softirqs_off); | |
1985 | } | |
1986 | ||
1987 | #endif | |
1988 | ||
1989 | /* | |
1990 | * Initialize a lock instance's lock-class mapping info: | |
1991 | */ | |
1992 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 1993 | struct lock_class_key *key, int subclass) |
fbb9ce95 IM |
1994 | { |
1995 | if (unlikely(!debug_locks)) | |
1996 | return; | |
1997 | ||
1998 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
1999 | return; | |
2000 | if (DEBUG_LOCKS_WARN_ON(!name)) | |
2001 | return; | |
2002 | /* | |
2003 | * Sanity check, the lock-class key must be persistent: | |
2004 | */ | |
2005 | if (!static_obj(key)) { | |
2006 | printk("BUG: key %p not in .data!\n", key); | |
2007 | DEBUG_LOCKS_WARN_ON(1); | |
2008 | return; | |
2009 | } | |
2010 | lock->name = name; | |
2011 | lock->key = key; | |
d6d897ce | 2012 | lock->class_cache = NULL; |
4dfbb9d8 PZ |
2013 | if (subclass) |
2014 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 IM |
2015 | } |
2016 | ||
2017 | EXPORT_SYMBOL_GPL(lockdep_init_map); | |
2018 | ||
2019 | /* | |
2020 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2021 | * We maintain the dependency maps and validate the locking attempt: | |
2022 | */ | |
2023 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2024 | int trylock, int read, int check, int hardirqs_off, | |
2025 | unsigned long ip) | |
2026 | { | |
2027 | struct task_struct *curr = current; | |
d6d897ce | 2028 | struct lock_class *class = NULL; |
fbb9ce95 | 2029 | struct held_lock *hlock; |
fbb9ce95 IM |
2030 | unsigned int depth, id; |
2031 | int chain_head = 0; | |
2032 | u64 chain_key; | |
2033 | ||
2034 | if (unlikely(!debug_locks)) | |
2035 | return 0; | |
2036 | ||
2037 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2038 | return 0; | |
2039 | ||
2040 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2041 | debug_locks_off(); | |
2042 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2043 | printk("turning off the locking correctness validator.\n"); | |
2044 | return 0; | |
2045 | } | |
2046 | ||
d6d897ce IM |
2047 | if (!subclass) |
2048 | class = lock->class_cache; | |
2049 | /* | |
2050 | * Not cached yet or subclass? | |
2051 | */ | |
fbb9ce95 | 2052 | if (unlikely(!class)) { |
4dfbb9d8 | 2053 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2054 | if (!class) |
2055 | return 0; | |
2056 | } | |
2057 | debug_atomic_inc((atomic_t *)&class->ops); | |
2058 | if (very_verbose(class)) { | |
2059 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2060 | if (class->name_version > 1) | |
2061 | printk("#%d", class->name_version); | |
2062 | printk("\n"); | |
2063 | dump_stack(); | |
2064 | } | |
2065 | ||
2066 | /* | |
2067 | * Add the lock to the list of currently held locks. | |
2068 | * (we dont increase the depth just yet, up until the | |
2069 | * dependency checks are done) | |
2070 | */ | |
2071 | depth = curr->lockdep_depth; | |
2072 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2073 | return 0; | |
2074 | ||
2075 | hlock = curr->held_locks + depth; | |
2076 | ||
2077 | hlock->class = class; | |
2078 | hlock->acquire_ip = ip; | |
2079 | hlock->instance = lock; | |
2080 | hlock->trylock = trylock; | |
2081 | hlock->read = read; | |
2082 | hlock->check = check; | |
2083 | hlock->hardirqs_off = hardirqs_off; | |
2084 | ||
2085 | if (check != 2) | |
2086 | goto out_calc_hash; | |
2087 | #ifdef CONFIG_TRACE_IRQFLAGS | |
2088 | /* | |
2089 | * If non-trylock use in a hardirq or softirq context, then | |
2090 | * mark the lock as used in these contexts: | |
2091 | */ | |
2092 | if (!trylock) { | |
2093 | if (read) { | |
2094 | if (curr->hardirq_context) | |
2095 | if (!mark_lock(curr, hlock, | |
4ff773bb | 2096 | LOCK_USED_IN_HARDIRQ_READ)) |
fbb9ce95 IM |
2097 | return 0; |
2098 | if (curr->softirq_context) | |
2099 | if (!mark_lock(curr, hlock, | |
4ff773bb | 2100 | LOCK_USED_IN_SOFTIRQ_READ)) |
fbb9ce95 IM |
2101 | return 0; |
2102 | } else { | |
2103 | if (curr->hardirq_context) | |
4ff773bb | 2104 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) |
fbb9ce95 IM |
2105 | return 0; |
2106 | if (curr->softirq_context) | |
4ff773bb | 2107 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) |
fbb9ce95 IM |
2108 | return 0; |
2109 | } | |
2110 | } | |
2111 | if (!hardirqs_off) { | |
2112 | if (read) { | |
2113 | if (!mark_lock(curr, hlock, | |
4ff773bb | 2114 | LOCK_ENABLED_HARDIRQS_READ)) |
fbb9ce95 IM |
2115 | return 0; |
2116 | if (curr->softirqs_enabled) | |
2117 | if (!mark_lock(curr, hlock, | |
4ff773bb | 2118 | LOCK_ENABLED_SOFTIRQS_READ)) |
fbb9ce95 IM |
2119 | return 0; |
2120 | } else { | |
2121 | if (!mark_lock(curr, hlock, | |
4ff773bb | 2122 | LOCK_ENABLED_HARDIRQS)) |
fbb9ce95 IM |
2123 | return 0; |
2124 | if (curr->softirqs_enabled) | |
2125 | if (!mark_lock(curr, hlock, | |
4ff773bb | 2126 | LOCK_ENABLED_SOFTIRQS)) |
fbb9ce95 IM |
2127 | return 0; |
2128 | } | |
2129 | } | |
2130 | #endif | |
2131 | /* mark it as used: */ | |
4ff773bb | 2132 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 IM |
2133 | return 0; |
2134 | out_calc_hash: | |
2135 | /* | |
2136 | * Calculate the chain hash: it's the combined has of all the | |
2137 | * lock keys along the dependency chain. We save the hash value | |
2138 | * at every step so that we can get the current hash easily | |
2139 | * after unlock. The chain hash is then used to cache dependency | |
2140 | * results. | |
2141 | * | |
2142 | * The 'key ID' is what is the most compact key value to drive | |
2143 | * the hash, not class->key. | |
2144 | */ | |
2145 | id = class - lock_classes; | |
2146 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2147 | return 0; | |
2148 | ||
2149 | chain_key = curr->curr_chain_key; | |
2150 | if (!depth) { | |
2151 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2152 | return 0; | |
2153 | chain_head = 1; | |
2154 | } | |
2155 | ||
2156 | hlock->prev_chain_key = chain_key; | |
2157 | ||
2158 | #ifdef CONFIG_TRACE_IRQFLAGS | |
2159 | /* | |
2160 | * Keep track of points where we cross into an interrupt context: | |
2161 | */ | |
2162 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2163 | curr->softirq_context; | |
2164 | if (depth) { | |
2165 | struct held_lock *prev_hlock; | |
2166 | ||
2167 | prev_hlock = curr->held_locks + depth-1; | |
2168 | /* | |
2169 | * If we cross into another context, reset the | |
2170 | * hash key (this also prevents the checking and the | |
2171 | * adding of the dependency to 'prev'): | |
2172 | */ | |
2173 | if (prev_hlock->irq_context != hlock->irq_context) { | |
2174 | chain_key = 0; | |
2175 | chain_head = 1; | |
2176 | } | |
2177 | } | |
2178 | #endif | |
2179 | chain_key = iterate_chain_key(chain_key, id); | |
2180 | curr->curr_chain_key = chain_key; | |
2181 | ||
2182 | /* | |
2183 | * Trylock needs to maintain the stack of held locks, but it | |
2184 | * does not add new dependencies, because trylock can be done | |
2185 | * in any order. | |
2186 | * | |
2187 | * We look up the chain_key and do the O(N^2) check and update of | |
2188 | * the dependencies only if this is a new dependency chain. | |
2189 | * (If lookup_chain_cache() returns with 1 it acquires | |
74c383f1 | 2190 | * graph_lock for us) |
fbb9ce95 | 2191 | */ |
81fc685a | 2192 | if (!trylock && (check == 2) && lookup_chain_cache(chain_key, class)) { |
fbb9ce95 IM |
2193 | /* |
2194 | * Check whether last held lock: | |
2195 | * | |
2196 | * - is irq-safe, if this lock is irq-unsafe | |
2197 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2198 | * | |
2199 | * And check whether the new lock's dependency graph | |
2200 | * could lead back to the previous lock. | |
2201 | * | |
2202 | * any of these scenarios could lead to a deadlock. If | |
2203 | * All validations | |
2204 | */ | |
2205 | int ret = check_deadlock(curr, hlock, lock, read); | |
2206 | ||
2207 | if (!ret) | |
2208 | return 0; | |
2209 | /* | |
2210 | * Mark recursive read, as we jump over it when | |
2211 | * building dependencies (just like we jump over | |
2212 | * trylock entries): | |
2213 | */ | |
2214 | if (ret == 2) | |
2215 | hlock->read = 2; | |
2216 | /* | |
2217 | * Add dependency only if this lock is not the head | |
2218 | * of the chain, and if it's not a secondary read-lock: | |
2219 | */ | |
2220 | if (!chain_head && ret != 2) | |
2221 | if (!check_prevs_add(curr, hlock)) | |
2222 | return 0; | |
74c383f1 | 2223 | graph_unlock(); |
381a2292 JP |
2224 | } else |
2225 | /* after lookup_chain_cache(): */ | |
2226 | if (unlikely(!debug_locks)) | |
2227 | return 0; | |
2228 | ||
fbb9ce95 IM |
2229 | curr->lockdep_depth++; |
2230 | check_chain_key(curr); | |
60e114d1 JP |
2231 | #ifdef CONFIG_DEBUG_LOCKDEP |
2232 | if (unlikely(!debug_locks)) | |
2233 | return 0; | |
2234 | #endif | |
fbb9ce95 IM |
2235 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2236 | debug_locks_off(); | |
2237 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2238 | printk("turning off the locking correctness validator.\n"); | |
2239 | return 0; | |
2240 | } | |
381a2292 | 2241 | |
fbb9ce95 IM |
2242 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2243 | max_lockdep_depth = curr->lockdep_depth; | |
2244 | ||
2245 | return 1; | |
2246 | } | |
2247 | ||
2248 | static int | |
2249 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2250 | unsigned long ip) | |
2251 | { | |
2252 | if (!debug_locks_off()) | |
2253 | return 0; | |
2254 | if (debug_locks_silent) | |
2255 | return 0; | |
2256 | ||
2257 | printk("\n=====================================\n"); | |
2258 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2259 | printk( "-------------------------------------\n"); | |
2260 | printk("%s/%d is trying to release lock (", | |
2261 | curr->comm, curr->pid); | |
2262 | print_lockdep_cache(lock); | |
2263 | printk(") at:\n"); | |
2264 | print_ip_sym(ip); | |
2265 | printk("but there are no more locks to release!\n"); | |
2266 | printk("\nother info that might help us debug this:\n"); | |
2267 | lockdep_print_held_locks(curr); | |
2268 | ||
2269 | printk("\nstack backtrace:\n"); | |
2270 | dump_stack(); | |
2271 | ||
2272 | return 0; | |
2273 | } | |
2274 | ||
2275 | /* | |
2276 | * Common debugging checks for both nested and non-nested unlock: | |
2277 | */ | |
2278 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2279 | unsigned long ip) | |
2280 | { | |
2281 | if (unlikely(!debug_locks)) | |
2282 | return 0; | |
2283 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2284 | return 0; | |
2285 | ||
2286 | if (curr->lockdep_depth <= 0) | |
2287 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2288 | ||
2289 | return 1; | |
2290 | } | |
2291 | ||
2292 | /* | |
2293 | * Remove the lock to the list of currently held locks in a | |
2294 | * potentially non-nested (out of order) manner. This is a | |
2295 | * relatively rare operation, as all the unlock APIs default | |
2296 | * to nested mode (which uses lock_release()): | |
2297 | */ | |
2298 | static int | |
2299 | lock_release_non_nested(struct task_struct *curr, | |
2300 | struct lockdep_map *lock, unsigned long ip) | |
2301 | { | |
2302 | struct held_lock *hlock, *prev_hlock; | |
2303 | unsigned int depth; | |
2304 | int i; | |
2305 | ||
2306 | /* | |
2307 | * Check whether the lock exists in the current stack | |
2308 | * of held locks: | |
2309 | */ | |
2310 | depth = curr->lockdep_depth; | |
2311 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2312 | return 0; | |
2313 | ||
2314 | prev_hlock = NULL; | |
2315 | for (i = depth-1; i >= 0; i--) { | |
2316 | hlock = curr->held_locks + i; | |
2317 | /* | |
2318 | * We must not cross into another context: | |
2319 | */ | |
2320 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2321 | break; | |
2322 | if (hlock->instance == lock) | |
2323 | goto found_it; | |
2324 | prev_hlock = hlock; | |
2325 | } | |
2326 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2327 | ||
2328 | found_it: | |
2329 | /* | |
2330 | * We have the right lock to unlock, 'hlock' points to it. | |
2331 | * Now we remove it from the stack, and add back the other | |
2332 | * entries (if any), recalculating the hash along the way: | |
2333 | */ | |
2334 | curr->lockdep_depth = i; | |
2335 | curr->curr_chain_key = hlock->prev_chain_key; | |
2336 | ||
2337 | for (i++; i < depth; i++) { | |
2338 | hlock = curr->held_locks + i; | |
2339 | if (!__lock_acquire(hlock->instance, | |
2340 | hlock->class->subclass, hlock->trylock, | |
2341 | hlock->read, hlock->check, hlock->hardirqs_off, | |
2342 | hlock->acquire_ip)) | |
2343 | return 0; | |
2344 | } | |
2345 | ||
2346 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2347 | return 0; | |
2348 | return 1; | |
2349 | } | |
2350 | ||
2351 | /* | |
2352 | * Remove the lock to the list of currently held locks - this gets | |
2353 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2354 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2355 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2356 | */ | |
2357 | static int lock_release_nested(struct task_struct *curr, | |
2358 | struct lockdep_map *lock, unsigned long ip) | |
2359 | { | |
2360 | struct held_lock *hlock; | |
2361 | unsigned int depth; | |
2362 | ||
2363 | /* | |
2364 | * Pop off the top of the lock stack: | |
2365 | */ | |
2366 | depth = curr->lockdep_depth - 1; | |
2367 | hlock = curr->held_locks + depth; | |
2368 | ||
2369 | /* | |
2370 | * Is the unlock non-nested: | |
2371 | */ | |
2372 | if (hlock->instance != lock) | |
2373 | return lock_release_non_nested(curr, lock, ip); | |
2374 | curr->lockdep_depth--; | |
2375 | ||
2376 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2377 | return 0; | |
2378 | ||
2379 | curr->curr_chain_key = hlock->prev_chain_key; | |
2380 | ||
2381 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2382 | hlock->prev_chain_key = 0; | |
2383 | hlock->class = NULL; | |
2384 | hlock->acquire_ip = 0; | |
2385 | hlock->irq_context = 0; | |
2386 | #endif | |
2387 | return 1; | |
2388 | } | |
2389 | ||
2390 | /* | |
2391 | * Remove the lock to the list of currently held locks - this gets | |
2392 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2393 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2394 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2395 | */ | |
2396 | static void | |
2397 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2398 | { | |
2399 | struct task_struct *curr = current; | |
2400 | ||
2401 | if (!check_unlock(curr, lock, ip)) | |
2402 | return; | |
2403 | ||
2404 | if (nested) { | |
2405 | if (!lock_release_nested(curr, lock, ip)) | |
2406 | return; | |
2407 | } else { | |
2408 | if (!lock_release_non_nested(curr, lock, ip)) | |
2409 | return; | |
2410 | } | |
2411 | ||
2412 | check_chain_key(curr); | |
2413 | } | |
2414 | ||
2415 | /* | |
2416 | * Check whether we follow the irq-flags state precisely: | |
2417 | */ | |
2418 | static void check_flags(unsigned long flags) | |
2419 | { | |
2420 | #if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS) | |
2421 | if (!debug_locks) | |
2422 | return; | |
2423 | ||
2424 | if (irqs_disabled_flags(flags)) | |
2425 | DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled); | |
2426 | else | |
2427 | DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled); | |
2428 | ||
2429 | /* | |
2430 | * We dont accurately track softirq state in e.g. | |
2431 | * hardirq contexts (such as on 4KSTACKS), so only | |
2432 | * check if not in hardirq contexts: | |
2433 | */ | |
2434 | if (!hardirq_count()) { | |
2435 | if (softirq_count()) | |
2436 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
2437 | else | |
2438 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
2439 | } | |
2440 | ||
2441 | if (!debug_locks) | |
2442 | print_irqtrace_events(current); | |
2443 | #endif | |
2444 | } | |
2445 | ||
2446 | /* | |
2447 | * We are not always called with irqs disabled - do that here, | |
2448 | * and also avoid lockdep recursion: | |
2449 | */ | |
2450 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2451 | int trylock, int read, int check, unsigned long ip) | |
2452 | { | |
2453 | unsigned long flags; | |
2454 | ||
2455 | if (unlikely(current->lockdep_recursion)) | |
2456 | return; | |
2457 | ||
2458 | raw_local_irq_save(flags); | |
2459 | check_flags(flags); | |
2460 | ||
2461 | current->lockdep_recursion = 1; | |
2462 | __lock_acquire(lock, subclass, trylock, read, check, | |
2463 | irqs_disabled_flags(flags), ip); | |
2464 | current->lockdep_recursion = 0; | |
2465 | raw_local_irq_restore(flags); | |
2466 | } | |
2467 | ||
2468 | EXPORT_SYMBOL_GPL(lock_acquire); | |
2469 | ||
2470 | void lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2471 | { | |
2472 | unsigned long flags; | |
2473 | ||
2474 | if (unlikely(current->lockdep_recursion)) | |
2475 | return; | |
2476 | ||
2477 | raw_local_irq_save(flags); | |
2478 | check_flags(flags); | |
2479 | current->lockdep_recursion = 1; | |
2480 | __lock_release(lock, nested, ip); | |
2481 | current->lockdep_recursion = 0; | |
2482 | raw_local_irq_restore(flags); | |
2483 | } | |
2484 | ||
2485 | EXPORT_SYMBOL_GPL(lock_release); | |
2486 | ||
2487 | /* | |
2488 | * Used by the testsuite, sanitize the validator state | |
2489 | * after a simulated failure: | |
2490 | */ | |
2491 | ||
2492 | void lockdep_reset(void) | |
2493 | { | |
2494 | unsigned long flags; | |
23d95a03 | 2495 | int i; |
fbb9ce95 IM |
2496 | |
2497 | raw_local_irq_save(flags); | |
2498 | current->curr_chain_key = 0; | |
2499 | current->lockdep_depth = 0; | |
2500 | current->lockdep_recursion = 0; | |
2501 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
2502 | nr_hardirq_chains = 0; | |
2503 | nr_softirq_chains = 0; | |
2504 | nr_process_chains = 0; | |
2505 | debug_locks = 1; | |
23d95a03 IM |
2506 | for (i = 0; i < CHAINHASH_SIZE; i++) |
2507 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
2508 | raw_local_irq_restore(flags); |
2509 | } | |
2510 | ||
2511 | static void zap_class(struct lock_class *class) | |
2512 | { | |
2513 | int i; | |
2514 | ||
2515 | /* | |
2516 | * Remove all dependencies this lock is | |
2517 | * involved in: | |
2518 | */ | |
2519 | for (i = 0; i < nr_list_entries; i++) { | |
2520 | if (list_entries[i].class == class) | |
2521 | list_del_rcu(&list_entries[i].entry); | |
2522 | } | |
2523 | /* | |
2524 | * Unhash the class and remove it from the all_lock_classes list: | |
2525 | */ | |
2526 | list_del_rcu(&class->hash_entry); | |
2527 | list_del_rcu(&class->lock_entry); | |
2528 | ||
2529 | } | |
2530 | ||
2531 | static inline int within(void *addr, void *start, unsigned long size) | |
2532 | { | |
2533 | return addr >= start && addr < start + size; | |
2534 | } | |
2535 | ||
2536 | void lockdep_free_key_range(void *start, unsigned long size) | |
2537 | { | |
2538 | struct lock_class *class, *next; | |
2539 | struct list_head *head; | |
2540 | unsigned long flags; | |
2541 | int i; | |
2542 | ||
2543 | raw_local_irq_save(flags); | |
74c383f1 | 2544 | graph_lock(); |
fbb9ce95 IM |
2545 | |
2546 | /* | |
2547 | * Unhash all classes that were created by this module: | |
2548 | */ | |
2549 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
2550 | head = classhash_table + i; | |
2551 | if (list_empty(head)) | |
2552 | continue; | |
2553 | list_for_each_entry_safe(class, next, head, hash_entry) | |
2554 | if (within(class->key, start, size)) | |
2555 | zap_class(class); | |
2556 | } | |
2557 | ||
74c383f1 | 2558 | graph_unlock(); |
fbb9ce95 IM |
2559 | raw_local_irq_restore(flags); |
2560 | } | |
2561 | ||
2562 | void lockdep_reset_lock(struct lockdep_map *lock) | |
2563 | { | |
d6d897ce | 2564 | struct lock_class *class, *next; |
fbb9ce95 IM |
2565 | struct list_head *head; |
2566 | unsigned long flags; | |
2567 | int i, j; | |
2568 | ||
2569 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
2570 | |
2571 | /* | |
d6d897ce IM |
2572 | * Remove all classes this lock might have: |
2573 | */ | |
2574 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
2575 | /* | |
2576 | * If the class exists we look it up and zap it: | |
2577 | */ | |
2578 | class = look_up_lock_class(lock, j); | |
2579 | if (class) | |
2580 | zap_class(class); | |
2581 | } | |
2582 | /* | |
2583 | * Debug check: in the end all mapped classes should | |
2584 | * be gone. | |
fbb9ce95 | 2585 | */ |
74c383f1 | 2586 | graph_lock(); |
fbb9ce95 IM |
2587 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
2588 | head = classhash_table + i; | |
2589 | if (list_empty(head)) | |
2590 | continue; | |
2591 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 2592 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
2593 | if (debug_locks_off_graph_unlock()) |
2594 | WARN_ON(1); | |
d6d897ce | 2595 | goto out_restore; |
fbb9ce95 IM |
2596 | } |
2597 | } | |
2598 | } | |
74c383f1 | 2599 | graph_unlock(); |
d6d897ce IM |
2600 | |
2601 | out_restore: | |
fbb9ce95 IM |
2602 | raw_local_irq_restore(flags); |
2603 | } | |
2604 | ||
1499993c | 2605 | void lockdep_init(void) |
fbb9ce95 IM |
2606 | { |
2607 | int i; | |
2608 | ||
2609 | /* | |
2610 | * Some architectures have their own start_kernel() | |
2611 | * code which calls lockdep_init(), while we also | |
2612 | * call lockdep_init() from the start_kernel() itself, | |
2613 | * and we want to initialize the hashes only once: | |
2614 | */ | |
2615 | if (lockdep_initialized) | |
2616 | return; | |
2617 | ||
2618 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
2619 | INIT_LIST_HEAD(classhash_table + i); | |
2620 | ||
2621 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
2622 | INIT_LIST_HEAD(chainhash_table + i); | |
2623 | ||
2624 | lockdep_initialized = 1; | |
2625 | } | |
2626 | ||
2627 | void __init lockdep_info(void) | |
2628 | { | |
2629 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
2630 | ||
2631 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); | |
2632 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); | |
2633 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
2634 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); | |
2635 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); | |
2636 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
2637 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
2638 | ||
2639 | printk(" memory used by lock dependency info: %lu kB\n", | |
2640 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
2641 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
2642 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
2643 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
2644 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
2645 | ||
2646 | printk(" per task-struct memory footprint: %lu bytes\n", | |
2647 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
2648 | ||
2649 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2650 | if (lockdep_init_error) | |
2651 | printk("WARNING: lockdep init error! Arch code didnt call lockdep_init() early enough?\n"); | |
2652 | #endif | |
2653 | } | |
2654 | ||
2655 | static inline int in_range(const void *start, const void *addr, const void *end) | |
2656 | { | |
2657 | return addr >= start && addr <= end; | |
2658 | } | |
2659 | ||
2660 | static void | |
2661 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 2662 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
2663 | { |
2664 | if (!debug_locks_off()) | |
2665 | return; | |
2666 | if (debug_locks_silent) | |
2667 | return; | |
2668 | ||
2669 | printk("\n=========================\n"); | |
2670 | printk( "[ BUG: held lock freed! ]\n"); | |
2671 | printk( "-------------------------\n"); | |
2672 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
2673 | curr->comm, curr->pid, mem_from, mem_to-1); | |
55794a41 | 2674 | print_lock(hlock); |
fbb9ce95 IM |
2675 | lockdep_print_held_locks(curr); |
2676 | ||
2677 | printk("\nstack backtrace:\n"); | |
2678 | dump_stack(); | |
2679 | } | |
2680 | ||
2681 | /* | |
2682 | * Called when kernel memory is freed (or unmapped), or if a lock | |
2683 | * is destroyed or reinitialized - this code checks whether there is | |
2684 | * any held lock in the memory range of <from> to <to>: | |
2685 | */ | |
2686 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
2687 | { | |
2688 | const void *mem_to = mem_from + mem_len, *lock_from, *lock_to; | |
2689 | struct task_struct *curr = current; | |
2690 | struct held_lock *hlock; | |
2691 | unsigned long flags; | |
2692 | int i; | |
2693 | ||
2694 | if (unlikely(!debug_locks)) | |
2695 | return; | |
2696 | ||
2697 | local_irq_save(flags); | |
2698 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2699 | hlock = curr->held_locks + i; | |
2700 | ||
2701 | lock_from = (void *)hlock->instance; | |
2702 | lock_to = (void *)(hlock->instance + 1); | |
2703 | ||
2704 | if (!in_range(mem_from, lock_from, mem_to) && | |
2705 | !in_range(mem_from, lock_to, mem_to)) | |
2706 | continue; | |
2707 | ||
55794a41 | 2708 | print_freed_lock_bug(curr, mem_from, mem_to, hlock); |
fbb9ce95 IM |
2709 | break; |
2710 | } | |
2711 | local_irq_restore(flags); | |
2712 | } | |
ed07536e | 2713 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
2714 | |
2715 | static void print_held_locks_bug(struct task_struct *curr) | |
2716 | { | |
2717 | if (!debug_locks_off()) | |
2718 | return; | |
2719 | if (debug_locks_silent) | |
2720 | return; | |
2721 | ||
2722 | printk("\n=====================================\n"); | |
2723 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
2724 | printk( "-------------------------------------\n"); | |
2725 | printk("%s/%d is exiting with locks still held!\n", | |
2726 | curr->comm, curr->pid); | |
2727 | lockdep_print_held_locks(curr); | |
2728 | ||
2729 | printk("\nstack backtrace:\n"); | |
2730 | dump_stack(); | |
2731 | } | |
2732 | ||
2733 | void debug_check_no_locks_held(struct task_struct *task) | |
2734 | { | |
2735 | if (unlikely(task->lockdep_depth > 0)) | |
2736 | print_held_locks_bug(task); | |
2737 | } | |
2738 | ||
2739 | void debug_show_all_locks(void) | |
2740 | { | |
2741 | struct task_struct *g, *p; | |
2742 | int count = 10; | |
2743 | int unlock = 1; | |
2744 | ||
9c35dd7f JP |
2745 | if (unlikely(!debug_locks)) { |
2746 | printk("INFO: lockdep is turned off.\n"); | |
2747 | return; | |
2748 | } | |
fbb9ce95 IM |
2749 | printk("\nShowing all locks held in the system:\n"); |
2750 | ||
2751 | /* | |
2752 | * Here we try to get the tasklist_lock as hard as possible, | |
2753 | * if not successful after 2 seconds we ignore it (but keep | |
2754 | * trying). This is to enable a debug printout even if a | |
2755 | * tasklist_lock-holding task deadlocks or crashes. | |
2756 | */ | |
2757 | retry: | |
2758 | if (!read_trylock(&tasklist_lock)) { | |
2759 | if (count == 10) | |
2760 | printk("hm, tasklist_lock locked, retrying... "); | |
2761 | if (count) { | |
2762 | count--; | |
2763 | printk(" #%d", 10-count); | |
2764 | mdelay(200); | |
2765 | goto retry; | |
2766 | } | |
2767 | printk(" ignoring it.\n"); | |
2768 | unlock = 0; | |
2769 | } | |
2770 | if (count != 10) | |
2771 | printk(" locked it.\n"); | |
2772 | ||
2773 | do_each_thread(g, p) { | |
2774 | if (p->lockdep_depth) | |
2775 | lockdep_print_held_locks(p); | |
2776 | if (!unlock) | |
2777 | if (read_trylock(&tasklist_lock)) | |
2778 | unlock = 1; | |
2779 | } while_each_thread(g, p); | |
2780 | ||
2781 | printk("\n"); | |
2782 | printk("=============================================\n\n"); | |
2783 | ||
2784 | if (unlock) | |
2785 | read_unlock(&tasklist_lock); | |
2786 | } | |
2787 | ||
2788 | EXPORT_SYMBOL_GPL(debug_show_all_locks); | |
2789 | ||
2790 | void debug_show_held_locks(struct task_struct *task) | |
2791 | { | |
9c35dd7f JP |
2792 | if (unlikely(!debug_locks)) { |
2793 | printk("INFO: lockdep is turned off.\n"); | |
2794 | return; | |
2795 | } | |
fbb9ce95 IM |
2796 | lockdep_print_held_locks(task); |
2797 | } | |
2798 | ||
2799 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |