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