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Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
af012961 | 46 | |
fbb9ce95 IM |
47 | #include <asm/sections.h> |
48 | ||
49 | #include "lockdep_internals.h" | |
50 | ||
a8d154b0 | 51 | #define CREATE_TRACE_POINTS |
ad8d75ff | 52 | #include <trace/events/lockdep.h> |
a8d154b0 | 53 | |
f20786ff PZ |
54 | #ifdef CONFIG_PROVE_LOCKING |
55 | int prove_locking = 1; | |
56 | module_param(prove_locking, int, 0644); | |
57 | #else | |
58 | #define prove_locking 0 | |
59 | #endif | |
60 | ||
61 | #ifdef CONFIG_LOCK_STAT | |
62 | int lock_stat = 1; | |
63 | module_param(lock_stat, int, 0644); | |
64 | #else | |
65 | #define lock_stat 0 | |
66 | #endif | |
67 | ||
fbb9ce95 | 68 | /* |
74c383f1 IM |
69 | * lockdep_lock: protects the lockdep graph, the hashes and the |
70 | * class/list/hash allocators. | |
fbb9ce95 IM |
71 | * |
72 | * This is one of the rare exceptions where it's justified | |
73 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 74 | * code to recurse back into the lockdep code... |
fbb9ce95 | 75 | */ |
74c383f1 IM |
76 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
77 | ||
78 | static int graph_lock(void) | |
79 | { | |
80 | __raw_spin_lock(&lockdep_lock); | |
81 | /* | |
82 | * Make sure that if another CPU detected a bug while | |
83 | * walking the graph we dont change it (while the other | |
84 | * CPU is busy printing out stuff with the graph lock | |
85 | * dropped already) | |
86 | */ | |
87 | if (!debug_locks) { | |
88 | __raw_spin_unlock(&lockdep_lock); | |
89 | return 0; | |
90 | } | |
bb065afb SR |
91 | /* prevent any recursions within lockdep from causing deadlocks */ |
92 | current->lockdep_recursion++; | |
74c383f1 IM |
93 | return 1; |
94 | } | |
95 | ||
96 | static inline int graph_unlock(void) | |
97 | { | |
381a2292 JP |
98 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
99 | return DEBUG_LOCKS_WARN_ON(1); | |
100 | ||
bb065afb | 101 | current->lockdep_recursion--; |
74c383f1 IM |
102 | __raw_spin_unlock(&lockdep_lock); |
103 | return 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * Turn lock debugging off and return with 0 if it was off already, | |
108 | * and also release the graph lock: | |
109 | */ | |
110 | static inline int debug_locks_off_graph_unlock(void) | |
111 | { | |
112 | int ret = debug_locks_off(); | |
113 | ||
114 | __raw_spin_unlock(&lockdep_lock); | |
115 | ||
116 | return ret; | |
117 | } | |
fbb9ce95 IM |
118 | |
119 | static int lockdep_initialized; | |
120 | ||
121 | unsigned long nr_list_entries; | |
af012961 | 122 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 123 | |
fbb9ce95 IM |
124 | /* |
125 | * All data structures here are protected by the global debug_lock. | |
126 | * | |
127 | * Mutex key structs only get allocated, once during bootup, and never | |
128 | * get freed - this significantly simplifies the debugging code. | |
129 | */ | |
130 | unsigned long nr_lock_classes; | |
131 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
132 | ||
f82b217e DJ |
133 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
134 | { | |
135 | if (!hlock->class_idx) { | |
136 | DEBUG_LOCKS_WARN_ON(1); | |
137 | return NULL; | |
138 | } | |
139 | return lock_classes + hlock->class_idx - 1; | |
140 | } | |
141 | ||
f20786ff PZ |
142 | #ifdef CONFIG_LOCK_STAT |
143 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); | |
144 | ||
c7e78cff | 145 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
146 | { |
147 | int i; | |
148 | ||
c7e78cff PZ |
149 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
150 | if (points[i] == 0) { | |
151 | points[i] = ip; | |
f20786ff PZ |
152 | break; |
153 | } | |
c7e78cff | 154 | if (points[i] == ip) |
f20786ff PZ |
155 | break; |
156 | } | |
157 | ||
158 | return i; | |
159 | } | |
160 | ||
161 | static void lock_time_inc(struct lock_time *lt, s64 time) | |
162 | { | |
163 | if (time > lt->max) | |
164 | lt->max = time; | |
165 | ||
166 | if (time < lt->min || !lt->min) | |
167 | lt->min = time; | |
168 | ||
169 | lt->total += time; | |
170 | lt->nr++; | |
171 | } | |
172 | ||
c46261de PZ |
173 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
174 | { | |
175 | dst->min += src->min; | |
176 | dst->max += src->max; | |
177 | dst->total += src->total; | |
178 | dst->nr += src->nr; | |
179 | } | |
180 | ||
181 | struct lock_class_stats lock_stats(struct lock_class *class) | |
182 | { | |
183 | struct lock_class_stats stats; | |
184 | int cpu, i; | |
185 | ||
186 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
187 | for_each_possible_cpu(cpu) { | |
188 | struct lock_class_stats *pcs = | |
189 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
190 | ||
191 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
192 | stats.contention_point[i] += pcs->contention_point[i]; | |
193 | ||
c7e78cff PZ |
194 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
195 | stats.contending_point[i] += pcs->contending_point[i]; | |
196 | ||
c46261de PZ |
197 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
198 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
199 | ||
200 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
201 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
202 | |
203 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
204 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
205 | } |
206 | ||
207 | return stats; | |
208 | } | |
209 | ||
210 | void clear_lock_stats(struct lock_class *class) | |
211 | { | |
212 | int cpu; | |
213 | ||
214 | for_each_possible_cpu(cpu) { | |
215 | struct lock_class_stats *cpu_stats = | |
216 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
217 | ||
218 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
219 | } | |
220 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 221 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
222 | } |
223 | ||
f20786ff PZ |
224 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
225 | { | |
226 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
227 | } | |
228 | ||
229 | static void put_lock_stats(struct lock_class_stats *stats) | |
230 | { | |
231 | put_cpu_var(lock_stats); | |
232 | } | |
233 | ||
234 | static void lock_release_holdtime(struct held_lock *hlock) | |
235 | { | |
236 | struct lock_class_stats *stats; | |
237 | s64 holdtime; | |
238 | ||
239 | if (!lock_stat) | |
240 | return; | |
241 | ||
242 | holdtime = sched_clock() - hlock->holdtime_stamp; | |
243 | ||
f82b217e | 244 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
245 | if (hlock->read) |
246 | lock_time_inc(&stats->read_holdtime, holdtime); | |
247 | else | |
248 | lock_time_inc(&stats->write_holdtime, holdtime); | |
249 | put_lock_stats(stats); | |
250 | } | |
251 | #else | |
252 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
253 | { | |
254 | } | |
255 | #endif | |
256 | ||
fbb9ce95 IM |
257 | /* |
258 | * We keep a global list of all lock classes. The list only grows, | |
259 | * never shrinks. The list is only accessed with the lockdep | |
260 | * spinlock lock held. | |
261 | */ | |
262 | LIST_HEAD(all_lock_classes); | |
263 | ||
264 | /* | |
265 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
266 | */ | |
267 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
268 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 269 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
270 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
271 | ||
272 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
273 | ||
fbb9ce95 IM |
274 | /* |
275 | * We put the lock dependency chains into a hash-table as well, to cache | |
276 | * their existence: | |
277 | */ | |
278 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
279 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 280 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
281 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
282 | ||
283 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
284 | ||
285 | /* | |
286 | * The hash key of the lock dependency chains is a hash itself too: | |
287 | * it's a hash of all locks taken up to that lock, including that lock. | |
288 | * It's a 64-bit hash, because it's important for the keys to be | |
289 | * unique. | |
290 | */ | |
291 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
292 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
293 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
294 | (key2)) |
295 | ||
1d09daa5 | 296 | void lockdep_off(void) |
fbb9ce95 IM |
297 | { |
298 | current->lockdep_recursion++; | |
299 | } | |
fbb9ce95 IM |
300 | EXPORT_SYMBOL(lockdep_off); |
301 | ||
1d09daa5 | 302 | void lockdep_on(void) |
fbb9ce95 IM |
303 | { |
304 | current->lockdep_recursion--; | |
305 | } | |
fbb9ce95 IM |
306 | EXPORT_SYMBOL(lockdep_on); |
307 | ||
fbb9ce95 IM |
308 | /* |
309 | * Debugging switches: | |
310 | */ | |
311 | ||
312 | #define VERBOSE 0 | |
33e94e96 | 313 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
314 | |
315 | #if VERBOSE | |
316 | # define HARDIRQ_VERBOSE 1 | |
317 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 318 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
319 | #else |
320 | # define HARDIRQ_VERBOSE 0 | |
321 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 322 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
323 | #endif |
324 | ||
cf40bd16 | 325 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
326 | /* |
327 | * Quick filtering for interesting events: | |
328 | */ | |
329 | static int class_filter(struct lock_class *class) | |
330 | { | |
f9829cce AK |
331 | #if 0 |
332 | /* Example */ | |
fbb9ce95 | 333 | if (class->name_version == 1 && |
f9829cce | 334 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
335 | return 1; |
336 | if (class->name_version == 1 && | |
f9829cce | 337 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 338 | return 1; |
f9829cce | 339 | #endif |
a6640897 IM |
340 | /* Filter everything else. 1 would be to allow everything else */ |
341 | return 0; | |
fbb9ce95 IM |
342 | } |
343 | #endif | |
344 | ||
345 | static int verbose(struct lock_class *class) | |
346 | { | |
347 | #if VERBOSE | |
348 | return class_filter(class); | |
349 | #endif | |
350 | return 0; | |
351 | } | |
352 | ||
fbb9ce95 IM |
353 | /* |
354 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 355 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
356 | */ |
357 | unsigned long nr_stack_trace_entries; | |
358 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
359 | ||
360 | static int save_trace(struct stack_trace *trace) | |
361 | { | |
362 | trace->nr_entries = 0; | |
363 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
364 | trace->entries = stack_trace + nr_stack_trace_entries; | |
365 | ||
5a1b3999 | 366 | trace->skip = 3; |
5a1b3999 | 367 | |
ab1b6f03 | 368 | save_stack_trace(trace); |
fbb9ce95 | 369 | |
4f84f433 PZ |
370 | /* |
371 | * Some daft arches put -1 at the end to indicate its a full trace. | |
372 | * | |
373 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
374 | * complete trace that maxes out the entries provided will be reported | |
375 | * as incomplete, friggin useless </rant> | |
376 | */ | |
377 | if (trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
378 | trace->nr_entries--; | |
379 | ||
fbb9ce95 IM |
380 | trace->max_entries = trace->nr_entries; |
381 | ||
382 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 383 | |
4f84f433 | 384 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
385 | if (!debug_locks_off_graph_unlock()) |
386 | return 0; | |
387 | ||
388 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
389 | printk("turning off the locking correctness validator.\n"); | |
390 | dump_stack(); | |
391 | ||
fbb9ce95 IM |
392 | return 0; |
393 | } | |
394 | ||
395 | return 1; | |
396 | } | |
397 | ||
398 | unsigned int nr_hardirq_chains; | |
399 | unsigned int nr_softirq_chains; | |
400 | unsigned int nr_process_chains; | |
401 | unsigned int max_lockdep_depth; | |
402 | unsigned int max_recursion_depth; | |
403 | ||
404 | #ifdef CONFIG_DEBUG_LOCKDEP | |
405 | /* | |
406 | * We cannot printk in early bootup code. Not even early_printk() | |
407 | * might work. So we mark any initialization errors and printk | |
408 | * about it later on, in lockdep_info(). | |
409 | */ | |
410 | static int lockdep_init_error; | |
c71063c9 JB |
411 | static unsigned long lockdep_init_trace_data[20]; |
412 | static struct stack_trace lockdep_init_trace = { | |
413 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
414 | .entries = lockdep_init_trace_data, | |
415 | }; | |
fbb9ce95 IM |
416 | |
417 | /* | |
418 | * Various lockdep statistics: | |
419 | */ | |
420 | atomic_t chain_lookup_hits; | |
421 | atomic_t chain_lookup_misses; | |
422 | atomic_t hardirqs_on_events; | |
423 | atomic_t hardirqs_off_events; | |
424 | atomic_t redundant_hardirqs_on; | |
425 | atomic_t redundant_hardirqs_off; | |
426 | atomic_t softirqs_on_events; | |
427 | atomic_t softirqs_off_events; | |
428 | atomic_t redundant_softirqs_on; | |
429 | atomic_t redundant_softirqs_off; | |
430 | atomic_t nr_unused_locks; | |
431 | atomic_t nr_cyclic_checks; | |
432 | atomic_t nr_cyclic_check_recursions; | |
433 | atomic_t nr_find_usage_forwards_checks; | |
434 | atomic_t nr_find_usage_forwards_recursions; | |
435 | atomic_t nr_find_usage_backwards_checks; | |
436 | atomic_t nr_find_usage_backwards_recursions; | |
fbb9ce95 IM |
437 | #endif |
438 | ||
439 | /* | |
440 | * Locking printouts: | |
441 | */ | |
442 | ||
fabe9c42 | 443 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
444 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
445 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
446 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
447 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 448 | |
fbb9ce95 IM |
449 | static const char *usage_str[] = |
450 | { | |
fabe9c42 PZ |
451 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
452 | #include "lockdep_states.h" | |
453 | #undef LOCKDEP_STATE | |
454 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
455 | }; |
456 | ||
457 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
458 | { | |
ffb45122 | 459 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
460 | } |
461 | ||
3ff176ca | 462 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 463 | { |
3ff176ca PZ |
464 | return 1UL << bit; |
465 | } | |
fbb9ce95 | 466 | |
3ff176ca PZ |
467 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
468 | { | |
469 | char c = '.'; | |
470 | ||
471 | if (class->usage_mask & lock_flag(bit + 2)) | |
472 | c = '+'; | |
473 | if (class->usage_mask & lock_flag(bit)) { | |
474 | c = '-'; | |
475 | if (class->usage_mask & lock_flag(bit + 2)) | |
476 | c = '?'; | |
fbb9ce95 IM |
477 | } |
478 | ||
3ff176ca PZ |
479 | return c; |
480 | } | |
cf40bd16 | 481 | |
f510b233 | 482 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 483 | { |
f510b233 | 484 | int i = 0; |
cf40bd16 | 485 | |
f510b233 PZ |
486 | #define LOCKDEP_STATE(__STATE) \ |
487 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
488 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
489 | #include "lockdep_states.h" | |
490 | #undef LOCKDEP_STATE | |
491 | ||
492 | usage[i] = '\0'; | |
fbb9ce95 IM |
493 | } |
494 | ||
495 | static void print_lock_name(struct lock_class *class) | |
496 | { | |
f510b233 | 497 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
498 | const char *name; |
499 | ||
f510b233 | 500 | get_usage_chars(class, usage); |
fbb9ce95 IM |
501 | |
502 | name = class->name; | |
503 | if (!name) { | |
504 | name = __get_key_name(class->key, str); | |
505 | printk(" (%s", name); | |
506 | } else { | |
507 | printk(" (%s", name); | |
508 | if (class->name_version > 1) | |
509 | printk("#%d", class->name_version); | |
510 | if (class->subclass) | |
511 | printk("/%d", class->subclass); | |
512 | } | |
f510b233 | 513 | printk("){%s}", usage); |
fbb9ce95 IM |
514 | } |
515 | ||
516 | static void print_lockdep_cache(struct lockdep_map *lock) | |
517 | { | |
518 | const char *name; | |
9281acea | 519 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
520 | |
521 | name = lock->name; | |
522 | if (!name) | |
523 | name = __get_key_name(lock->key->subkeys, str); | |
524 | ||
525 | printk("%s", name); | |
526 | } | |
527 | ||
528 | static void print_lock(struct held_lock *hlock) | |
529 | { | |
f82b217e | 530 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
531 | printk(", at: "); |
532 | print_ip_sym(hlock->acquire_ip); | |
533 | } | |
534 | ||
535 | static void lockdep_print_held_locks(struct task_struct *curr) | |
536 | { | |
537 | int i, depth = curr->lockdep_depth; | |
538 | ||
539 | if (!depth) { | |
ba25f9dc | 540 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
541 | return; |
542 | } | |
543 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 544 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
545 | |
546 | for (i = 0; i < depth; i++) { | |
547 | printk(" #%d: ", i); | |
548 | print_lock(curr->held_locks + i); | |
549 | } | |
550 | } | |
fbb9ce95 | 551 | |
8e18257d PZ |
552 | static void print_kernel_version(void) |
553 | { | |
554 | printk("%s %.*s\n", init_utsname()->release, | |
555 | (int)strcspn(init_utsname()->version, " "), | |
556 | init_utsname()->version); | |
557 | } | |
558 | ||
559 | static int very_verbose(struct lock_class *class) | |
560 | { | |
561 | #if VERY_VERBOSE | |
562 | return class_filter(class); | |
563 | #endif | |
564 | return 0; | |
565 | } | |
566 | ||
fbb9ce95 | 567 | /* |
8e18257d | 568 | * Is this the address of a static object: |
fbb9ce95 | 569 | */ |
8e18257d | 570 | static int static_obj(void *obj) |
fbb9ce95 | 571 | { |
8e18257d PZ |
572 | unsigned long start = (unsigned long) &_stext, |
573 | end = (unsigned long) &_end, | |
574 | addr = (unsigned long) obj; | |
575 | #ifdef CONFIG_SMP | |
576 | int i; | |
577 | #endif | |
578 | ||
fbb9ce95 | 579 | /* |
8e18257d | 580 | * static variable? |
fbb9ce95 | 581 | */ |
8e18257d PZ |
582 | if ((addr >= start) && (addr < end)) |
583 | return 1; | |
fbb9ce95 | 584 | |
8e18257d | 585 | #ifdef CONFIG_SMP |
fbb9ce95 | 586 | /* |
8e18257d | 587 | * percpu var? |
fbb9ce95 | 588 | */ |
8e18257d PZ |
589 | for_each_possible_cpu(i) { |
590 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
591 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
592 | + per_cpu_offset(i); | |
fbb9ce95 | 593 | |
8e18257d PZ |
594 | if ((addr >= start) && (addr < end)) |
595 | return 1; | |
596 | } | |
ca58abcb | 597 | #endif |
fbb9ce95 | 598 | |
8e18257d PZ |
599 | /* |
600 | * module var? | |
601 | */ | |
602 | return is_module_address(addr); | |
99de055a DJ |
603 | } |
604 | ||
fbb9ce95 | 605 | /* |
8e18257d PZ |
606 | * To make lock name printouts unique, we calculate a unique |
607 | * class->name_version generation counter: | |
fbb9ce95 | 608 | */ |
8e18257d | 609 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 610 | { |
8e18257d PZ |
611 | struct lock_class *class; |
612 | int count = 0; | |
fbb9ce95 | 613 | |
8e18257d | 614 | if (!new_class->name) |
fbb9ce95 IM |
615 | return 0; |
616 | ||
8e18257d PZ |
617 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
618 | if (new_class->key - new_class->subclass == class->key) | |
619 | return class->name_version; | |
620 | if (class->name && !strcmp(class->name, new_class->name)) | |
621 | count = max(count, class->name_version); | |
622 | } | |
fbb9ce95 | 623 | |
8e18257d | 624 | return count + 1; |
fbb9ce95 IM |
625 | } |
626 | ||
8e18257d PZ |
627 | /* |
628 | * Register a lock's class in the hash-table, if the class is not present | |
629 | * yet. Otherwise we look it up. We cache the result in the lock object | |
630 | * itself, so actual lookup of the hash should be once per lock object. | |
631 | */ | |
632 | static inline struct lock_class * | |
633 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 634 | { |
8e18257d PZ |
635 | struct lockdep_subclass_key *key; |
636 | struct list_head *hash_head; | |
637 | struct lock_class *class; | |
fbb9ce95 | 638 | |
8e18257d PZ |
639 | #ifdef CONFIG_DEBUG_LOCKDEP |
640 | /* | |
641 | * If the architecture calls into lockdep before initializing | |
642 | * the hashes then we'll warn about it later. (we cannot printk | |
643 | * right now) | |
644 | */ | |
645 | if (unlikely(!lockdep_initialized)) { | |
646 | lockdep_init(); | |
647 | lockdep_init_error = 1; | |
c71063c9 | 648 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
649 | } |
650 | #endif | |
fbb9ce95 | 651 | |
8e18257d PZ |
652 | /* |
653 | * Static locks do not have their class-keys yet - for them the key | |
654 | * is the lock object itself: | |
655 | */ | |
656 | if (unlikely(!lock->key)) | |
657 | lock->key = (void *)lock; | |
fbb9ce95 | 658 | |
8e18257d PZ |
659 | /* |
660 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
661 | * lock_class_key variable is passed in through the mutex_init() | |
662 | * (or spin_lock_init()) call - which acts as the key. For static | |
663 | * locks we use the lock object itself as the key. | |
664 | */ | |
4b32d0a4 PZ |
665 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
666 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 667 | |
8e18257d | 668 | key = lock->key->subkeys + subclass; |
ca268c69 | 669 | |
8e18257d | 670 | hash_head = classhashentry(key); |
74c383f1 | 671 | |
8e18257d PZ |
672 | /* |
673 | * We can walk the hash lockfree, because the hash only | |
674 | * grows, and we are careful when adding entries to the end: | |
675 | */ | |
4b32d0a4 PZ |
676 | list_for_each_entry(class, hash_head, hash_entry) { |
677 | if (class->key == key) { | |
678 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 679 | return class; |
4b32d0a4 PZ |
680 | } |
681 | } | |
fbb9ce95 | 682 | |
8e18257d | 683 | return NULL; |
fbb9ce95 IM |
684 | } |
685 | ||
686 | /* | |
8e18257d PZ |
687 | * Register a lock's class in the hash-table, if the class is not present |
688 | * yet. Otherwise we look it up. We cache the result in the lock object | |
689 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 690 | */ |
8e18257d PZ |
691 | static inline struct lock_class * |
692 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 693 | { |
8e18257d PZ |
694 | struct lockdep_subclass_key *key; |
695 | struct list_head *hash_head; | |
696 | struct lock_class *class; | |
697 | unsigned long flags; | |
698 | ||
699 | class = look_up_lock_class(lock, subclass); | |
700 | if (likely(class)) | |
701 | return class; | |
702 | ||
703 | /* | |
704 | * Debug-check: all keys must be persistent! | |
705 | */ | |
706 | if (!static_obj(lock->key)) { | |
707 | debug_locks_off(); | |
708 | printk("INFO: trying to register non-static key.\n"); | |
709 | printk("the code is fine but needs lockdep annotation.\n"); | |
710 | printk("turning off the locking correctness validator.\n"); | |
711 | dump_stack(); | |
712 | ||
713 | return NULL; | |
714 | } | |
715 | ||
716 | key = lock->key->subkeys + subclass; | |
717 | hash_head = classhashentry(key); | |
718 | ||
719 | raw_local_irq_save(flags); | |
720 | if (!graph_lock()) { | |
721 | raw_local_irq_restore(flags); | |
722 | return NULL; | |
723 | } | |
724 | /* | |
725 | * We have to do the hash-walk again, to avoid races | |
726 | * with another CPU: | |
727 | */ | |
728 | list_for_each_entry(class, hash_head, hash_entry) | |
729 | if (class->key == key) | |
730 | goto out_unlock_set; | |
731 | /* | |
732 | * Allocate a new key from the static array, and add it to | |
733 | * the hash: | |
734 | */ | |
735 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
736 | if (!debug_locks_off_graph_unlock()) { | |
737 | raw_local_irq_restore(flags); | |
738 | return NULL; | |
739 | } | |
740 | raw_local_irq_restore(flags); | |
741 | ||
742 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
743 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 744 | dump_stack(); |
8e18257d PZ |
745 | return NULL; |
746 | } | |
747 | class = lock_classes + nr_lock_classes++; | |
748 | debug_atomic_inc(&nr_unused_locks); | |
749 | class->key = key; | |
750 | class->name = lock->name; | |
751 | class->subclass = subclass; | |
752 | INIT_LIST_HEAD(&class->lock_entry); | |
753 | INIT_LIST_HEAD(&class->locks_before); | |
754 | INIT_LIST_HEAD(&class->locks_after); | |
755 | class->name_version = count_matching_names(class); | |
756 | /* | |
757 | * We use RCU's safe list-add method to make | |
758 | * parallel walking of the hash-list safe: | |
759 | */ | |
760 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
761 | /* |
762 | * Add it to the global list of classes: | |
763 | */ | |
764 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
765 | |
766 | if (verbose(class)) { | |
767 | graph_unlock(); | |
768 | raw_local_irq_restore(flags); | |
769 | ||
770 | printk("\nnew class %p: %s", class->key, class->name); | |
771 | if (class->name_version > 1) | |
772 | printk("#%d", class->name_version); | |
773 | printk("\n"); | |
774 | dump_stack(); | |
775 | ||
776 | raw_local_irq_save(flags); | |
777 | if (!graph_lock()) { | |
778 | raw_local_irq_restore(flags); | |
779 | return NULL; | |
780 | } | |
781 | } | |
782 | out_unlock_set: | |
783 | graph_unlock(); | |
784 | raw_local_irq_restore(flags); | |
785 | ||
786 | if (!subclass || force) | |
787 | lock->class_cache = class; | |
788 | ||
789 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
790 | return NULL; | |
791 | ||
792 | return class; | |
793 | } | |
794 | ||
795 | #ifdef CONFIG_PROVE_LOCKING | |
796 | /* | |
797 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
798 | * with NULL on failure) | |
799 | */ | |
800 | static struct lock_list *alloc_list_entry(void) | |
801 | { | |
802 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
803 | if (!debug_locks_off_graph_unlock()) | |
804 | return NULL; | |
805 | ||
806 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
807 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 808 | dump_stack(); |
8e18257d PZ |
809 | return NULL; |
810 | } | |
811 | return list_entries + nr_list_entries++; | |
812 | } | |
813 | ||
814 | /* | |
815 | * Add a new dependency to the head of the list: | |
816 | */ | |
817 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
818 | struct list_head *head, unsigned long ip, int distance) | |
819 | { | |
820 | struct lock_list *entry; | |
821 | /* | |
822 | * Lock not present yet - get a new dependency struct and | |
823 | * add it to the list: | |
824 | */ | |
825 | entry = alloc_list_entry(); | |
826 | if (!entry) | |
827 | return 0; | |
828 | ||
8e18257d PZ |
829 | if (!save_trace(&entry->trace)) |
830 | return 0; | |
831 | ||
74870172 ZY |
832 | entry->class = this; |
833 | entry->distance = distance; | |
8e18257d PZ |
834 | /* |
835 | * Since we never remove from the dependency list, the list can | |
836 | * be walked lockless by other CPUs, it's only allocation | |
837 | * that must be protected by the spinlock. But this also means | |
838 | * we must make new entries visible only once writes to the | |
839 | * entry become visible - hence the RCU op: | |
840 | */ | |
841 | list_add_tail_rcu(&entry->entry, head); | |
842 | ||
843 | return 1; | |
844 | } | |
845 | ||
af012961 PZ |
846 | /*For good efficiency of modular, we use power of 2*/ |
847 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL | |
848 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
849 | ||
850 | /* The circular_queue and helpers is used to implement the | |
851 | * breadth-first search(BFS)algorithem, by which we can build | |
852 | * the shortest path from the next lock to be acquired to the | |
853 | * previous held lock if there is a circular between them. | |
854 | * */ | |
855 | struct circular_queue { | |
856 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
857 | unsigned int front, rear; | |
858 | }; | |
859 | ||
860 | static struct circular_queue lock_cq; | |
861 | static unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)]; | |
862 | ||
12f3dfd0 | 863 | unsigned int max_bfs_queue_depth; |
af012961 PZ |
864 | |
865 | static inline void __cq_init(struct circular_queue *cq) | |
866 | { | |
867 | cq->front = cq->rear = 0; | |
868 | bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES); | |
869 | } | |
870 | ||
871 | static inline int __cq_empty(struct circular_queue *cq) | |
872 | { | |
873 | return (cq->front == cq->rear); | |
874 | } | |
875 | ||
876 | static inline int __cq_full(struct circular_queue *cq) | |
877 | { | |
878 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
879 | } | |
880 | ||
881 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
882 | { | |
883 | if (__cq_full(cq)) | |
884 | return -1; | |
885 | ||
886 | cq->element[cq->rear] = elem; | |
887 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
888 | return 0; | |
889 | } | |
890 | ||
891 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
892 | { | |
893 | if (__cq_empty(cq)) | |
894 | return -1; | |
895 | ||
896 | *elem = cq->element[cq->front]; | |
897 | cq->front = (cq->front + 1) & CQ_MASK; | |
898 | return 0; | |
899 | } | |
900 | ||
901 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
902 | { | |
903 | return (cq->rear - cq->front) & CQ_MASK; | |
904 | } | |
905 | ||
906 | static inline void mark_lock_accessed(struct lock_list *lock, | |
907 | struct lock_list *parent) | |
908 | { | |
909 | unsigned long nr; | |
910 | nr = lock - list_entries; | |
911 | WARN_ON(nr >= nr_list_entries); | |
912 | lock->parent = parent; | |
913 | set_bit(nr, bfs_accessed); | |
914 | } | |
915 | ||
916 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
917 | { | |
918 | unsigned long nr; | |
919 | nr = lock - list_entries; | |
920 | WARN_ON(nr >= nr_list_entries); | |
921 | return test_bit(nr, bfs_accessed); | |
922 | } | |
923 | ||
924 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
925 | { | |
926 | return child->parent; | |
927 | } | |
928 | ||
929 | static inline int get_lock_depth(struct lock_list *child) | |
930 | { | |
931 | int depth = 0; | |
932 | struct lock_list *parent; | |
933 | ||
934 | while ((parent = get_lock_parent(child))) { | |
935 | child = parent; | |
936 | depth++; | |
937 | } | |
938 | return depth; | |
939 | } | |
940 | ||
9e2d551e | 941 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
942 | void *data, |
943 | int (*match)(struct lock_list *entry, void *data), | |
944 | struct lock_list **target_entry, | |
945 | int forward) | |
c94aa5ca ML |
946 | { |
947 | struct lock_list *entry; | |
d588e461 | 948 | struct list_head *head; |
c94aa5ca ML |
949 | struct circular_queue *cq = &lock_cq; |
950 | int ret = 1; | |
951 | ||
9e2d551e | 952 | if (match(source_entry, data)) { |
c94aa5ca ML |
953 | *target_entry = source_entry; |
954 | ret = 0; | |
955 | goto exit; | |
956 | } | |
957 | ||
d588e461 ML |
958 | if (forward) |
959 | head = &source_entry->class->locks_after; | |
960 | else | |
961 | head = &source_entry->class->locks_before; | |
962 | ||
963 | if (list_empty(head)) | |
964 | goto exit; | |
965 | ||
966 | __cq_init(cq); | |
c94aa5ca ML |
967 | __cq_enqueue(cq, (unsigned long)source_entry); |
968 | ||
969 | while (!__cq_empty(cq)) { | |
970 | struct lock_list *lock; | |
c94aa5ca ML |
971 | |
972 | __cq_dequeue(cq, (unsigned long *)&lock); | |
973 | ||
974 | if (!lock->class) { | |
975 | ret = -2; | |
976 | goto exit; | |
977 | } | |
978 | ||
979 | if (forward) | |
980 | head = &lock->class->locks_after; | |
981 | else | |
982 | head = &lock->class->locks_before; | |
983 | ||
984 | list_for_each_entry(entry, head, entry) { | |
985 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 986 | unsigned int cq_depth; |
c94aa5ca | 987 | mark_lock_accessed(entry, lock); |
9e2d551e | 988 | if (match(entry, data)) { |
c94aa5ca ML |
989 | *target_entry = entry; |
990 | ret = 0; | |
991 | goto exit; | |
992 | } | |
993 | ||
994 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
995 | ret = -1; | |
996 | goto exit; | |
997 | } | |
12f3dfd0 ML |
998 | cq_depth = __cq_get_elem_count(cq); |
999 | if (max_bfs_queue_depth < cq_depth) | |
1000 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1001 | } |
1002 | } | |
1003 | } | |
1004 | exit: | |
1005 | return ret; | |
1006 | } | |
1007 | ||
d7aaba14 | 1008 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1009 | void *data, |
1010 | int (*match)(struct lock_list *entry, void *data), | |
1011 | struct lock_list **target_entry) | |
c94aa5ca | 1012 | { |
9e2d551e | 1013 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1014 | |
1015 | } | |
1016 | ||
d7aaba14 | 1017 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1018 | void *data, |
1019 | int (*match)(struct lock_list *entry, void *data), | |
1020 | struct lock_list **target_entry) | |
c94aa5ca | 1021 | { |
9e2d551e | 1022 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1023 | |
1024 | } | |
1025 | ||
8e18257d PZ |
1026 | /* |
1027 | * Recursive, forwards-direction lock-dependency checking, used for | |
1028 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1029 | * checking. | |
8e18257d | 1030 | */ |
8e18257d PZ |
1031 | |
1032 | /* | |
1033 | * Print a dependency chain entry (this is only done when a deadlock | |
1034 | * has been detected): | |
1035 | */ | |
1036 | static noinline int | |
24208ca7 | 1037 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1038 | { |
1039 | if (debug_locks_silent) | |
1040 | return 0; | |
1041 | printk("\n-> #%u", depth); | |
1042 | print_lock_name(target->class); | |
1043 | printk(":\n"); | |
1044 | print_stack_trace(&target->trace, 6); | |
1045 | ||
1046 | return 0; | |
1047 | } | |
1048 | ||
1049 | /* | |
1050 | * When a circular dependency is detected, print the | |
1051 | * header first: | |
1052 | */ | |
1053 | static noinline int | |
db0002a3 ML |
1054 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1055 | struct held_lock *check_src, | |
1056 | struct held_lock *check_tgt) | |
8e18257d PZ |
1057 | { |
1058 | struct task_struct *curr = current; | |
1059 | ||
c94aa5ca | 1060 | if (debug_locks_silent) |
8e18257d PZ |
1061 | return 0; |
1062 | ||
1063 | printk("\n=======================================================\n"); | |
1064 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1065 | print_kernel_version(); | |
1066 | printk( "-------------------------------------------------------\n"); | |
1067 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1068 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1069 | print_lock(check_src); |
8e18257d | 1070 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1071 | print_lock(check_tgt); |
8e18257d PZ |
1072 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1073 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1074 | ||
1075 | print_circular_bug_entry(entry, depth); | |
1076 | ||
1077 | return 0; | |
1078 | } | |
1079 | ||
9e2d551e ML |
1080 | static inline int class_equal(struct lock_list *entry, void *data) |
1081 | { | |
1082 | return entry->class == data; | |
1083 | } | |
1084 | ||
db0002a3 ML |
1085 | static noinline int print_circular_bug(struct lock_list *this, |
1086 | struct lock_list *target, | |
1087 | struct held_lock *check_src, | |
1088 | struct held_lock *check_tgt) | |
8e18257d PZ |
1089 | { |
1090 | struct task_struct *curr = current; | |
c94aa5ca | 1091 | struct lock_list *parent; |
24208ca7 | 1092 | int depth; |
8e18257d | 1093 | |
c94aa5ca | 1094 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1095 | return 0; |
1096 | ||
db0002a3 | 1097 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1098 | return 0; |
1099 | ||
c94aa5ca ML |
1100 | depth = get_lock_depth(target); |
1101 | ||
db0002a3 | 1102 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1103 | |
1104 | parent = get_lock_parent(target); | |
1105 | ||
1106 | while (parent) { | |
1107 | print_circular_bug_entry(parent, --depth); | |
1108 | parent = get_lock_parent(parent); | |
1109 | } | |
8e18257d PZ |
1110 | |
1111 | printk("\nother info that might help us debug this:\n\n"); | |
1112 | lockdep_print_held_locks(curr); | |
1113 | ||
1114 | printk("\nstack backtrace:\n"); | |
1115 | dump_stack(); | |
1116 | ||
1117 | return 0; | |
1118 | } | |
1119 | ||
db0002a3 ML |
1120 | static noinline int print_bfs_bug(int ret) |
1121 | { | |
1122 | if (!debug_locks_off_graph_unlock()) | |
1123 | return 0; | |
1124 | ||
1125 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1126 | ||
1127 | return 0; | |
1128 | } | |
1129 | ||
ef681026 | 1130 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1131 | { |
ef681026 ML |
1132 | (*(unsigned long *)data)++; |
1133 | return 0; | |
1134 | } | |
419ca3f1 | 1135 | |
ef681026 ML |
1136 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1137 | { | |
1138 | unsigned long count = 0; | |
1139 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1140 | |
ef681026 | 1141 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1142 | |
ef681026 | 1143 | return count; |
419ca3f1 | 1144 | } |
419ca3f1 DM |
1145 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1146 | { | |
1147 | unsigned long ret, flags; | |
ef681026 ML |
1148 | struct lock_list this; |
1149 | ||
1150 | this.parent = NULL; | |
1151 | this.class = class; | |
419ca3f1 DM |
1152 | |
1153 | local_irq_save(flags); | |
1154 | __raw_spin_lock(&lockdep_lock); | |
ef681026 | 1155 | ret = __lockdep_count_forward_deps(&this); |
419ca3f1 DM |
1156 | __raw_spin_unlock(&lockdep_lock); |
1157 | local_irq_restore(flags); | |
1158 | ||
1159 | return ret; | |
1160 | } | |
1161 | ||
ef681026 | 1162 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1163 | { |
ef681026 ML |
1164 | unsigned long count = 0; |
1165 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1166 | |
ef681026 | 1167 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1168 | |
ef681026 | 1169 | return count; |
419ca3f1 DM |
1170 | } |
1171 | ||
1172 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1173 | { | |
1174 | unsigned long ret, flags; | |
ef681026 ML |
1175 | struct lock_list this; |
1176 | ||
1177 | this.parent = NULL; | |
1178 | this.class = class; | |
419ca3f1 DM |
1179 | |
1180 | local_irq_save(flags); | |
1181 | __raw_spin_lock(&lockdep_lock); | |
ef681026 | 1182 | ret = __lockdep_count_backward_deps(&this); |
419ca3f1 DM |
1183 | __raw_spin_unlock(&lockdep_lock); |
1184 | local_irq_restore(flags); | |
1185 | ||
1186 | return ret; | |
1187 | } | |
1188 | ||
8e18257d PZ |
1189 | /* |
1190 | * Prove that the dependency graph starting at <entry> can not | |
1191 | * lead to <target>. Print an error and return 0 if it does. | |
1192 | */ | |
1193 | static noinline int | |
db0002a3 ML |
1194 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1195 | struct lock_list **target_entry) | |
8e18257d | 1196 | { |
db0002a3 | 1197 | int result; |
8e18257d | 1198 | |
db0002a3 | 1199 | debug_atomic_inc(&nr_cyclic_checks); |
419ca3f1 | 1200 | |
d7aaba14 | 1201 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1202 | |
db0002a3 ML |
1203 | return result; |
1204 | } | |
c94aa5ca | 1205 | |
81d68a96 | 1206 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1207 | /* |
1208 | * Forwards and backwards subgraph searching, for the purposes of | |
1209 | * proving that two subgraphs can be connected by a new dependency | |
1210 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1211 | */ | |
fbb9ce95 | 1212 | |
d7aaba14 ML |
1213 | static inline int usage_match(struct lock_list *entry, void *bit) |
1214 | { | |
1215 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1216 | } | |
1217 | ||
1218 | ||
1219 | ||
fbb9ce95 IM |
1220 | /* |
1221 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1222 | * at @root->class that matches @bit. |
fbb9ce95 | 1223 | * |
d7aaba14 ML |
1224 | * Return 0 if such a node exists in the subgraph, and put that node |
1225 | * into *@target_entry. | |
fbb9ce95 | 1226 | * |
d7aaba14 ML |
1227 | * Return 1 otherwise and keep *@target_entry unchanged. |
1228 | * Return <0 on error. | |
fbb9ce95 | 1229 | */ |
d7aaba14 ML |
1230 | static int |
1231 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1232 | struct lock_list **target_entry) | |
fbb9ce95 | 1233 | { |
d7aaba14 | 1234 | int result; |
fbb9ce95 IM |
1235 | |
1236 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
fbb9ce95 | 1237 | |
d7aaba14 ML |
1238 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1239 | ||
1240 | return result; | |
fbb9ce95 IM |
1241 | } |
1242 | ||
1243 | /* | |
1244 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1245 | * at @root->class that matches @bit. |
fbb9ce95 | 1246 | * |
d7aaba14 ML |
1247 | * Return 0 if such a node exists in the subgraph, and put that node |
1248 | * into *@target_entry. | |
fbb9ce95 | 1249 | * |
d7aaba14 ML |
1250 | * Return 1 otherwise and keep *@target_entry unchanged. |
1251 | * Return <0 on error. | |
fbb9ce95 | 1252 | */ |
d7aaba14 ML |
1253 | static int |
1254 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1255 | struct lock_list **target_entry) | |
fbb9ce95 | 1256 | { |
d7aaba14 | 1257 | int result; |
fbb9ce95 IM |
1258 | |
1259 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
fbb9ce95 | 1260 | |
d7aaba14 | 1261 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1262 | |
d7aaba14 | 1263 | return result; |
fbb9ce95 IM |
1264 | } |
1265 | ||
af012961 PZ |
1266 | static void print_lock_class_header(struct lock_class *class, int depth) |
1267 | { | |
1268 | int bit; | |
1269 | ||
1270 | printk("%*s->", depth, ""); | |
1271 | print_lock_name(class); | |
1272 | printk(" ops: %lu", class->ops); | |
1273 | printk(" {\n"); | |
1274 | ||
1275 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1276 | if (class->usage_mask & (1 << bit)) { | |
1277 | int len = depth; | |
1278 | ||
1279 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1280 | len += printk(" at:\n"); | |
1281 | print_stack_trace(class->usage_traces + bit, len); | |
1282 | } | |
1283 | } | |
1284 | printk("%*s }\n", depth, ""); | |
1285 | ||
1286 | printk("%*s ... key at: ",depth,""); | |
1287 | print_ip_sym((unsigned long)class->key); | |
1288 | } | |
1289 | ||
1290 | /* | |
1291 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1292 | */ | |
1293 | static void __used | |
1294 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1295 | struct lock_list *root) | |
1296 | { | |
1297 | struct lock_list *entry = leaf; | |
1298 | int depth; | |
1299 | ||
1300 | /*compute depth from generated tree by BFS*/ | |
1301 | depth = get_lock_depth(leaf); | |
1302 | ||
1303 | do { | |
1304 | print_lock_class_header(entry->class, depth); | |
1305 | printk("%*s ... acquired at:\n", depth, ""); | |
1306 | print_stack_trace(&entry->trace, 2); | |
1307 | printk("\n"); | |
1308 | ||
1309 | if (depth == 0 && (entry != root)) { | |
1310 | printk("lockdep:%s bad BFS generated tree\n", __func__); | |
1311 | break; | |
1312 | } | |
1313 | ||
1314 | entry = get_lock_parent(entry); | |
1315 | depth--; | |
1316 | } while (entry && (depth >= 0)); | |
1317 | ||
1318 | return; | |
1319 | } | |
d7aaba14 | 1320 | |
fbb9ce95 IM |
1321 | static int |
1322 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1323 | struct lock_list *prev_root, |
1324 | struct lock_list *next_root, | |
1325 | struct lock_list *backwards_entry, | |
1326 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1327 | struct held_lock *prev, |
1328 | struct held_lock *next, | |
1329 | enum lock_usage_bit bit1, | |
1330 | enum lock_usage_bit bit2, | |
1331 | const char *irqclass) | |
1332 | { | |
74c383f1 | 1333 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1334 | return 0; |
1335 | ||
1336 | printk("\n======================================================\n"); | |
1337 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1338 | irqclass, irqclass); | |
99de055a | 1339 | print_kernel_version(); |
fbb9ce95 IM |
1340 | printk( "------------------------------------------------------\n"); |
1341 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1342 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1343 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1344 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1345 | curr->hardirqs_enabled, | |
1346 | curr->softirqs_enabled); | |
1347 | print_lock(next); | |
1348 | ||
1349 | printk("\nand this task is already holding:\n"); | |
1350 | print_lock(prev); | |
1351 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1352 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1353 | printk(" ->"); |
f82b217e | 1354 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1355 | printk("\n"); |
1356 | ||
1357 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1358 | irqclass); | |
24208ca7 | 1359 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1360 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1361 | ||
24208ca7 | 1362 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1363 | |
1364 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1365 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1366 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1367 | printk("..."); | |
1368 | ||
24208ca7 | 1369 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1370 | |
1371 | printk("\nother info that might help us debug this:\n\n"); | |
1372 | lockdep_print_held_locks(curr); | |
1373 | ||
24208ca7 ML |
1374 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1375 | printk(" and the holding lock:\n"); | |
1376 | if (!save_trace(&prev_root->trace)) | |
1377 | return 0; | |
1378 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1379 | |
24208ca7 ML |
1380 | printk("\nthe dependencies between the lock to be acquired"); |
1381 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1382 | if (!save_trace(&next_root->trace)) | |
1383 | return 0; | |
1384 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1385 | |
1386 | printk("\nstack backtrace:\n"); | |
1387 | dump_stack(); | |
1388 | ||
1389 | return 0; | |
1390 | } | |
1391 | ||
1392 | static int | |
1393 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1394 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1395 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1396 | { | |
1397 | int ret; | |
24208ca7 | 1398 | struct lock_list this, that; |
d7aaba14 | 1399 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1400 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1401 | |
1402 | this.parent = NULL; | |
1403 | ||
1404 | this.class = hlock_class(prev); | |
1405 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1406 | if (ret < 0) |
1407 | return print_bfs_bug(ret); | |
1408 | if (ret == 1) | |
1409 | return ret; | |
d7aaba14 | 1410 | |
24208ca7 ML |
1411 | that.parent = NULL; |
1412 | that.class = hlock_class(next); | |
1413 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1414 | if (ret < 0) |
1415 | return print_bfs_bug(ret); | |
1416 | if (ret == 1) | |
1417 | return ret; | |
fbb9ce95 | 1418 | |
24208ca7 ML |
1419 | return print_bad_irq_dependency(curr, &this, &that, |
1420 | target_entry, target_entry1, | |
1421 | prev, next, | |
fbb9ce95 IM |
1422 | bit_backwards, bit_forwards, irqclass); |
1423 | } | |
1424 | ||
4f367d8a PZ |
1425 | static const char *state_names[] = { |
1426 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1427 | __stringify(__STATE), |
4f367d8a PZ |
1428 | #include "lockdep_states.h" |
1429 | #undef LOCKDEP_STATE | |
1430 | }; | |
1431 | ||
1432 | static const char *state_rnames[] = { | |
1433 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1434 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1435 | #include "lockdep_states.h" |
1436 | #undef LOCKDEP_STATE | |
1437 | }; | |
1438 | ||
1439 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1440 | { |
4f367d8a PZ |
1441 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1442 | } | |
8e18257d | 1443 | |
4f367d8a PZ |
1444 | static int exclusive_bit(int new_bit) |
1445 | { | |
8e18257d | 1446 | /* |
4f367d8a PZ |
1447 | * USED_IN |
1448 | * USED_IN_READ | |
1449 | * ENABLED | |
1450 | * ENABLED_READ | |
1451 | * | |
1452 | * bit 0 - write/read | |
1453 | * bit 1 - used_in/enabled | |
1454 | * bit 2+ state | |
8e18257d | 1455 | */ |
4f367d8a PZ |
1456 | |
1457 | int state = new_bit & ~3; | |
1458 | int dir = new_bit & 2; | |
8e18257d PZ |
1459 | |
1460 | /* | |
4f367d8a | 1461 | * keep state, bit flip the direction and strip read. |
8e18257d | 1462 | */ |
4f367d8a PZ |
1463 | return state | (dir ^ 2); |
1464 | } | |
1465 | ||
1466 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1467 | struct held_lock *next, enum lock_usage_bit bit) | |
1468 | { | |
8e18257d | 1469 | /* |
4f367d8a PZ |
1470 | * Prove that the new dependency does not connect a hardirq-safe |
1471 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1472 | * the backwards-subgraph starting at <prev>, and the |
1473 | * forwards-subgraph starting at <next>: | |
1474 | */ | |
4f367d8a PZ |
1475 | if (!check_usage(curr, prev, next, bit, |
1476 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1477 | return 0; |
1478 | ||
4f367d8a PZ |
1479 | bit++; /* _READ */ |
1480 | ||
cf40bd16 | 1481 | /* |
4f367d8a PZ |
1482 | * Prove that the new dependency does not connect a hardirq-safe-read |
1483 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1484 | * the backwards-subgraph starting at <prev>, and the |
1485 | * forwards-subgraph starting at <next>: | |
1486 | */ | |
4f367d8a PZ |
1487 | if (!check_usage(curr, prev, next, bit, |
1488 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1489 | return 0; |
1490 | ||
4f367d8a PZ |
1491 | return 1; |
1492 | } | |
1493 | ||
1494 | static int | |
1495 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1496 | struct held_lock *next) | |
1497 | { | |
1498 | #define LOCKDEP_STATE(__STATE) \ | |
1499 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1500 | return 0; |
4f367d8a PZ |
1501 | #include "lockdep_states.h" |
1502 | #undef LOCKDEP_STATE | |
cf40bd16 | 1503 | |
8e18257d PZ |
1504 | return 1; |
1505 | } | |
1506 | ||
1507 | static void inc_chains(void) | |
1508 | { | |
1509 | if (current->hardirq_context) | |
1510 | nr_hardirq_chains++; | |
1511 | else { | |
1512 | if (current->softirq_context) | |
1513 | nr_softirq_chains++; | |
1514 | else | |
1515 | nr_process_chains++; | |
1516 | } | |
1517 | } | |
1518 | ||
1519 | #else | |
1520 | ||
1521 | static inline int | |
1522 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1523 | struct held_lock *next) | |
1524 | { | |
1525 | return 1; | |
1526 | } | |
1527 | ||
1528 | static inline void inc_chains(void) | |
1529 | { | |
1530 | nr_process_chains++; | |
1531 | } | |
1532 | ||
fbb9ce95 IM |
1533 | #endif |
1534 | ||
1535 | static int | |
1536 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1537 | struct held_lock *next) | |
1538 | { | |
74c383f1 | 1539 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1540 | return 0; |
1541 | ||
1542 | printk("\n=============================================\n"); | |
1543 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1544 | print_kernel_version(); |
fbb9ce95 IM |
1545 | printk( "---------------------------------------------\n"); |
1546 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1547 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1548 | print_lock(next); |
1549 | printk("\nbut task is already holding lock:\n"); | |
1550 | print_lock(prev); | |
1551 | ||
1552 | printk("\nother info that might help us debug this:\n"); | |
1553 | lockdep_print_held_locks(curr); | |
1554 | ||
1555 | printk("\nstack backtrace:\n"); | |
1556 | dump_stack(); | |
1557 | ||
1558 | return 0; | |
1559 | } | |
1560 | ||
1561 | /* | |
1562 | * Check whether we are holding such a class already. | |
1563 | * | |
1564 | * (Note that this has to be done separately, because the graph cannot | |
1565 | * detect such classes of deadlocks.) | |
1566 | * | |
1567 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1568 | */ | |
1569 | static int | |
1570 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1571 | struct lockdep_map *next_instance, int read) | |
1572 | { | |
1573 | struct held_lock *prev; | |
7531e2f3 | 1574 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1575 | int i; |
1576 | ||
1577 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1578 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1579 | |
1580 | if (prev->instance == next->nest_lock) | |
1581 | nest = prev; | |
1582 | ||
f82b217e | 1583 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1584 | continue; |
7531e2f3 | 1585 | |
fbb9ce95 IM |
1586 | /* |
1587 | * Allow read-after-read recursion of the same | |
6c9076ec | 1588 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1589 | */ |
6c9076ec | 1590 | if ((read == 2) && prev->read) |
fbb9ce95 | 1591 | return 2; |
7531e2f3 PZ |
1592 | |
1593 | /* | |
1594 | * We're holding the nest_lock, which serializes this lock's | |
1595 | * nesting behaviour. | |
1596 | */ | |
1597 | if (nest) | |
1598 | return 2; | |
1599 | ||
fbb9ce95 IM |
1600 | return print_deadlock_bug(curr, prev, next); |
1601 | } | |
1602 | return 1; | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * There was a chain-cache miss, and we are about to add a new dependency | |
1607 | * to a previous lock. We recursively validate the following rules: | |
1608 | * | |
1609 | * - would the adding of the <prev> -> <next> dependency create a | |
1610 | * circular dependency in the graph? [== circular deadlock] | |
1611 | * | |
1612 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1613 | * (in the full backwards-subgraph starting at <prev>) with any | |
1614 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1615 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1616 | * | |
1617 | * - does the new prev->next dependency connect any softirq-safe lock | |
1618 | * (in the full backwards-subgraph starting at <prev>) with any | |
1619 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1620 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1621 | * | |
1622 | * any of these scenarios could lead to a deadlock. | |
1623 | * | |
1624 | * Then if all the validations pass, we add the forwards and backwards | |
1625 | * dependency. | |
1626 | */ | |
1627 | static int | |
1628 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1629 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1630 | { |
1631 | struct lock_list *entry; | |
1632 | int ret; | |
db0002a3 ML |
1633 | struct lock_list this; |
1634 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 IM |
1635 | |
1636 | /* | |
1637 | * Prove that the new <prev> -> <next> dependency would not | |
1638 | * create a circular dependency in the graph. (We do this by | |
1639 | * forward-recursing into the graph starting at <next>, and | |
1640 | * checking whether we can reach <prev>.) | |
1641 | * | |
1642 | * We are using global variables to control the recursion, to | |
1643 | * keep the stackframe size of the recursive functions low: | |
1644 | */ | |
db0002a3 ML |
1645 | this.class = hlock_class(next); |
1646 | this.parent = NULL; | |
1647 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1648 | if (unlikely(!ret)) | |
1649 | return print_circular_bug(&this, target_entry, next, prev); | |
1650 | else if (unlikely(ret < 0)) | |
1651 | return print_bfs_bug(ret); | |
c94aa5ca | 1652 | |
8e18257d | 1653 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1654 | return 0; |
1655 | ||
fbb9ce95 IM |
1656 | /* |
1657 | * For recursive read-locks we do all the dependency checks, | |
1658 | * but we dont store read-triggered dependencies (only | |
1659 | * write-triggered dependencies). This ensures that only the | |
1660 | * write-side dependencies matter, and that if for example a | |
1661 | * write-lock never takes any other locks, then the reads are | |
1662 | * equivalent to a NOP. | |
1663 | */ | |
1664 | if (next->read == 2 || prev->read == 2) | |
1665 | return 1; | |
1666 | /* | |
1667 | * Is the <prev> -> <next> dependency already present? | |
1668 | * | |
1669 | * (this may occur even though this is a new chain: consider | |
1670 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1671 | * chains - the second one will be new, but L1 already has | |
1672 | * L2 added to its dependency list, due to the first chain.) | |
1673 | */ | |
f82b217e DJ |
1674 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1675 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1676 | if (distance == 1) |
1677 | entry->distance = 1; | |
fbb9ce95 | 1678 | return 2; |
068135e6 | 1679 | } |
fbb9ce95 IM |
1680 | } |
1681 | ||
1682 | /* | |
1683 | * Ok, all validations passed, add the new lock | |
1684 | * to the previous lock's dependency list: | |
1685 | */ | |
f82b217e DJ |
1686 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1687 | &hlock_class(prev)->locks_after, | |
1688 | next->acquire_ip, distance); | |
068135e6 | 1689 | |
fbb9ce95 IM |
1690 | if (!ret) |
1691 | return 0; | |
910b1b2e | 1692 | |
f82b217e DJ |
1693 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1694 | &hlock_class(next)->locks_before, | |
1695 | next->acquire_ip, distance); | |
910b1b2e JP |
1696 | if (!ret) |
1697 | return 0; | |
fbb9ce95 IM |
1698 | |
1699 | /* | |
8e18257d PZ |
1700 | * Debugging printouts: |
1701 | */ | |
f82b217e | 1702 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1703 | graph_unlock(); |
1704 | printk("\n new dependency: "); | |
f82b217e | 1705 | print_lock_name(hlock_class(prev)); |
8e18257d | 1706 | printk(" => "); |
f82b217e | 1707 | print_lock_name(hlock_class(next)); |
8e18257d | 1708 | printk("\n"); |
fbb9ce95 | 1709 | dump_stack(); |
8e18257d | 1710 | return graph_lock(); |
fbb9ce95 | 1711 | } |
8e18257d PZ |
1712 | return 1; |
1713 | } | |
fbb9ce95 | 1714 | |
8e18257d PZ |
1715 | /* |
1716 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1717 | * The ones that are relevant are (in increasing distance from curr): | |
1718 | * all consecutive trylock entries and the final non-trylock entry - or | |
1719 | * the end of this context's lock-chain - whichever comes first. | |
1720 | */ | |
1721 | static int | |
1722 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1723 | { | |
1724 | int depth = curr->lockdep_depth; | |
1725 | struct held_lock *hlock; | |
d6d897ce | 1726 | |
fbb9ce95 | 1727 | /* |
8e18257d PZ |
1728 | * Debugging checks. |
1729 | * | |
1730 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1731 | */ |
8e18257d PZ |
1732 | if (!depth) |
1733 | goto out_bug; | |
fbb9ce95 | 1734 | /* |
8e18257d PZ |
1735 | * At least two relevant locks must exist for this |
1736 | * to be a head: | |
fbb9ce95 | 1737 | */ |
8e18257d PZ |
1738 | if (curr->held_locks[depth].irq_context != |
1739 | curr->held_locks[depth-1].irq_context) | |
1740 | goto out_bug; | |
74c383f1 | 1741 | |
8e18257d PZ |
1742 | for (;;) { |
1743 | int distance = curr->lockdep_depth - depth + 1; | |
1744 | hlock = curr->held_locks + depth-1; | |
1745 | /* | |
1746 | * Only non-recursive-read entries get new dependencies | |
1747 | * added: | |
1748 | */ | |
1749 | if (hlock->read != 2) { | |
1750 | if (!check_prev_add(curr, hlock, next, distance)) | |
1751 | return 0; | |
1752 | /* | |
1753 | * Stop after the first non-trylock entry, | |
1754 | * as non-trylock entries have added their | |
1755 | * own direct dependencies already, so this | |
1756 | * lock is connected to them indirectly: | |
1757 | */ | |
1758 | if (!hlock->trylock) | |
1759 | break; | |
74c383f1 | 1760 | } |
8e18257d PZ |
1761 | depth--; |
1762 | /* | |
1763 | * End of lock-stack? | |
1764 | */ | |
1765 | if (!depth) | |
1766 | break; | |
1767 | /* | |
1768 | * Stop the search if we cross into another context: | |
1769 | */ | |
1770 | if (curr->held_locks[depth].irq_context != | |
1771 | curr->held_locks[depth-1].irq_context) | |
1772 | break; | |
fbb9ce95 | 1773 | } |
8e18257d PZ |
1774 | return 1; |
1775 | out_bug: | |
1776 | if (!debug_locks_off_graph_unlock()) | |
1777 | return 0; | |
fbb9ce95 | 1778 | |
8e18257d | 1779 | WARN_ON(1); |
fbb9ce95 | 1780 | |
8e18257d | 1781 | return 0; |
fbb9ce95 IM |
1782 | } |
1783 | ||
8e18257d | 1784 | unsigned long nr_lock_chains; |
443cd507 | 1785 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1786 | int nr_chain_hlocks; |
443cd507 HY |
1787 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1788 | ||
1789 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1790 | { | |
1791 | return lock_classes + chain_hlocks[chain->base + i]; | |
1792 | } | |
8e18257d | 1793 | |
fbb9ce95 IM |
1794 | /* |
1795 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1796 | * add it and return 1 - in this case the new dependency chain is |
1797 | * validated. If the key is already hashed, return 0. | |
1798 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1799 | */ |
443cd507 HY |
1800 | static inline int lookup_chain_cache(struct task_struct *curr, |
1801 | struct held_lock *hlock, | |
1802 | u64 chain_key) | |
fbb9ce95 | 1803 | { |
f82b217e | 1804 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1805 | struct list_head *hash_head = chainhashentry(chain_key); |
1806 | struct lock_chain *chain; | |
443cd507 | 1807 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1808 | int i, j, n, cn; |
fbb9ce95 | 1809 | |
381a2292 JP |
1810 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1811 | return 0; | |
fbb9ce95 IM |
1812 | /* |
1813 | * We can walk it lock-free, because entries only get added | |
1814 | * to the hash: | |
1815 | */ | |
1816 | list_for_each_entry(chain, hash_head, entry) { | |
1817 | if (chain->chain_key == chain_key) { | |
1818 | cache_hit: | |
1819 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1820 | if (very_verbose(class)) |
755cd900 AM |
1821 | printk("\nhash chain already cached, key: " |
1822 | "%016Lx tail class: [%p] %s\n", | |
1823 | (unsigned long long)chain_key, | |
1824 | class->key, class->name); | |
fbb9ce95 IM |
1825 | return 0; |
1826 | } | |
1827 | } | |
81fc685a | 1828 | if (very_verbose(class)) |
755cd900 AM |
1829 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1830 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1831 | /* |
1832 | * Allocate a new chain entry from the static array, and add | |
1833 | * it to the hash: | |
1834 | */ | |
74c383f1 IM |
1835 | if (!graph_lock()) |
1836 | return 0; | |
fbb9ce95 IM |
1837 | /* |
1838 | * We have to walk the chain again locked - to avoid duplicates: | |
1839 | */ | |
1840 | list_for_each_entry(chain, hash_head, entry) { | |
1841 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1842 | graph_unlock(); |
fbb9ce95 IM |
1843 | goto cache_hit; |
1844 | } | |
1845 | } | |
1846 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1847 | if (!debug_locks_off_graph_unlock()) |
1848 | return 0; | |
1849 | ||
fbb9ce95 IM |
1850 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1851 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 1852 | dump_stack(); |
fbb9ce95 IM |
1853 | return 0; |
1854 | } | |
1855 | chain = lock_chains + nr_lock_chains++; | |
1856 | chain->chain_key = chain_key; | |
443cd507 HY |
1857 | chain->irq_context = hlock->irq_context; |
1858 | /* Find the first held_lock of current chain */ | |
1859 | hlock_next = hlock; | |
1860 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1861 | hlock_curr = curr->held_locks + i; | |
1862 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1863 | break; | |
1864 | hlock_next = hlock; | |
1865 | } | |
1866 | i++; | |
1867 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1868 | cn = nr_chain_hlocks; |
1869 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1870 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1871 | if (n == cn) | |
1872 | break; | |
1873 | cn = n; | |
1874 | } | |
1875 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1876 | chain->base = cn; | |
443cd507 | 1877 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1878 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1879 | chain_hlocks[chain->base + j] = lock_id; |
1880 | } | |
1881 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1882 | } | |
fbb9ce95 IM |
1883 | list_add_tail_rcu(&chain->entry, hash_head); |
1884 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1885 | inc_chains(); |
1886 | ||
1887 | return 1; | |
1888 | } | |
1889 | ||
1890 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1891 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1892 | { |
1893 | /* | |
1894 | * Trylock needs to maintain the stack of held locks, but it | |
1895 | * does not add new dependencies, because trylock can be done | |
1896 | * in any order. | |
1897 | * | |
1898 | * We look up the chain_key and do the O(N^2) check and update of | |
1899 | * the dependencies only if this is a new dependency chain. | |
1900 | * (If lookup_chain_cache() returns with 1 it acquires | |
1901 | * graph_lock for us) | |
1902 | */ | |
1903 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1904 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1905 | /* |
1906 | * Check whether last held lock: | |
1907 | * | |
1908 | * - is irq-safe, if this lock is irq-unsafe | |
1909 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1910 | * | |
1911 | * And check whether the new lock's dependency graph | |
1912 | * could lead back to the previous lock. | |
1913 | * | |
1914 | * any of these scenarios could lead to a deadlock. If | |
1915 | * All validations | |
1916 | */ | |
1917 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1918 | ||
1919 | if (!ret) | |
1920 | return 0; | |
1921 | /* | |
1922 | * Mark recursive read, as we jump over it when | |
1923 | * building dependencies (just like we jump over | |
1924 | * trylock entries): | |
1925 | */ | |
1926 | if (ret == 2) | |
1927 | hlock->read = 2; | |
1928 | /* | |
1929 | * Add dependency only if this lock is not the head | |
1930 | * of the chain, and if it's not a secondary read-lock: | |
1931 | */ | |
1932 | if (!chain_head && ret != 2) | |
1933 | if (!check_prevs_add(curr, hlock)) | |
1934 | return 0; | |
1935 | graph_unlock(); | |
1936 | } else | |
1937 | /* after lookup_chain_cache(): */ | |
1938 | if (unlikely(!debug_locks)) | |
1939 | return 0; | |
fbb9ce95 IM |
1940 | |
1941 | return 1; | |
1942 | } | |
8e18257d PZ |
1943 | #else |
1944 | static inline int validate_chain(struct task_struct *curr, | |
1945 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1946 | int chain_head, u64 chain_key) |
8e18257d PZ |
1947 | { |
1948 | return 1; | |
1949 | } | |
ca58abcb | 1950 | #endif |
fbb9ce95 IM |
1951 | |
1952 | /* | |
1953 | * We are building curr_chain_key incrementally, so double-check | |
1954 | * it from scratch, to make sure that it's done correctly: | |
1955 | */ | |
1d09daa5 | 1956 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1957 | { |
1958 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1959 | struct held_lock *hlock, *prev_hlock = NULL; | |
1960 | unsigned int i, id; | |
1961 | u64 chain_key = 0; | |
1962 | ||
1963 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1964 | hlock = curr->held_locks + i; | |
1965 | if (chain_key != hlock->prev_chain_key) { | |
1966 | debug_locks_off(); | |
2df8b1d6 | 1967 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1968 | curr->lockdep_depth, i, |
1969 | (unsigned long long)chain_key, | |
1970 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1971 | return; |
1972 | } | |
f82b217e | 1973 | id = hlock->class_idx - 1; |
381a2292 JP |
1974 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1975 | return; | |
1976 | ||
fbb9ce95 IM |
1977 | if (prev_hlock && (prev_hlock->irq_context != |
1978 | hlock->irq_context)) | |
1979 | chain_key = 0; | |
1980 | chain_key = iterate_chain_key(chain_key, id); | |
1981 | prev_hlock = hlock; | |
1982 | } | |
1983 | if (chain_key != curr->curr_chain_key) { | |
1984 | debug_locks_off(); | |
2df8b1d6 | 1985 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1986 | curr->lockdep_depth, i, |
1987 | (unsigned long long)chain_key, | |
1988 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1989 | } |
1990 | #endif | |
1991 | } | |
1992 | ||
8e18257d PZ |
1993 | static int |
1994 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1995 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1996 | { | |
1997 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1998 | return 0; | |
1999 | ||
2000 | printk("\n=================================\n"); | |
2001 | printk( "[ INFO: inconsistent lock state ]\n"); | |
2002 | print_kernel_version(); | |
2003 | printk( "---------------------------------\n"); | |
2004 | ||
2005 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2006 | usage_str[prev_bit], usage_str[new_bit]); | |
2007 | ||
2008 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2009 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2010 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2011 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2012 | trace_hardirqs_enabled(curr), | |
2013 | trace_softirqs_enabled(curr)); | |
2014 | print_lock(this); | |
2015 | ||
2016 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2017 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2018 | |
2019 | print_irqtrace_events(curr); | |
2020 | printk("\nother info that might help us debug this:\n"); | |
2021 | lockdep_print_held_locks(curr); | |
2022 | ||
2023 | printk("\nstack backtrace:\n"); | |
2024 | dump_stack(); | |
2025 | ||
2026 | return 0; | |
2027 | } | |
2028 | ||
2029 | /* | |
2030 | * Print out an error if an invalid bit is set: | |
2031 | */ | |
2032 | static inline int | |
2033 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2034 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2035 | { | |
f82b217e | 2036 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2037 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2038 | return 1; | |
2039 | } | |
2040 | ||
2041 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2042 | enum lock_usage_bit new_bit); | |
2043 | ||
81d68a96 | 2044 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2045 | |
2046 | /* | |
2047 | * print irq inversion bug: | |
2048 | */ | |
2049 | static int | |
24208ca7 ML |
2050 | print_irq_inversion_bug(struct task_struct *curr, |
2051 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2052 | struct held_lock *this, int forwards, |
2053 | const char *irqclass) | |
2054 | { | |
74c383f1 | 2055 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2056 | return 0; |
2057 | ||
2058 | printk("\n=========================================================\n"); | |
2059 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2060 | print_kernel_version(); |
fbb9ce95 IM |
2061 | printk( "---------------------------------------------------------\n"); |
2062 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2063 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2064 | print_lock(this); |
2065 | if (forwards) | |
26575e28 | 2066 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2067 | else |
26575e28 | 2068 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2069 | print_lock_name(other->class); |
fbb9ce95 IM |
2070 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2071 | ||
2072 | printk("\nother info that might help us debug this:\n"); | |
2073 | lockdep_print_held_locks(curr); | |
2074 | ||
24208ca7 ML |
2075 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2076 | if (!save_trace(&root->trace)) | |
2077 | return 0; | |
2078 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2079 | |
2080 | printk("\nstack backtrace:\n"); | |
2081 | dump_stack(); | |
2082 | ||
2083 | return 0; | |
2084 | } | |
2085 | ||
2086 | /* | |
2087 | * Prove that in the forwards-direction subgraph starting at <this> | |
2088 | * there is no lock matching <mask>: | |
2089 | */ | |
2090 | static int | |
2091 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2092 | enum lock_usage_bit bit, const char *irqclass) | |
2093 | { | |
2094 | int ret; | |
d7aaba14 ML |
2095 | struct lock_list root; |
2096 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2097 | |
d7aaba14 ML |
2098 | root.parent = NULL; |
2099 | root.class = hlock_class(this); | |
2100 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2101 | if (ret < 0) |
2102 | return print_bfs_bug(ret); | |
2103 | if (ret == 1) | |
2104 | return ret; | |
fbb9ce95 | 2105 | |
24208ca7 | 2106 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2107 | this, 1, irqclass); |
fbb9ce95 IM |
2108 | } |
2109 | ||
2110 | /* | |
2111 | * Prove that in the backwards-direction subgraph starting at <this> | |
2112 | * there is no lock matching <mask>: | |
2113 | */ | |
2114 | static int | |
2115 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2116 | enum lock_usage_bit bit, const char *irqclass) | |
2117 | { | |
2118 | int ret; | |
d7aaba14 ML |
2119 | struct lock_list root; |
2120 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2121 | |
d7aaba14 ML |
2122 | root.parent = NULL; |
2123 | root.class = hlock_class(this); | |
2124 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2125 | if (ret < 0) |
2126 | return print_bfs_bug(ret); | |
2127 | if (ret == 1) | |
2128 | return ret; | |
fbb9ce95 | 2129 | |
24208ca7 | 2130 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2131 | this, 1, irqclass); |
fbb9ce95 IM |
2132 | } |
2133 | ||
3117df04 | 2134 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2135 | { |
2136 | printk("irq event stamp: %u\n", curr->irq_events); | |
2137 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2138 | print_ip_sym(curr->hardirq_enable_ip); | |
2139 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2140 | print_ip_sym(curr->hardirq_disable_ip); | |
2141 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2142 | print_ip_sym(curr->softirq_enable_ip); | |
2143 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2144 | print_ip_sym(curr->softirq_disable_ip); | |
2145 | } | |
2146 | ||
cd95302d | 2147 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2148 | { |
8e18257d PZ |
2149 | #if HARDIRQ_VERBOSE |
2150 | return class_filter(class); | |
2151 | #endif | |
fbb9ce95 IM |
2152 | return 0; |
2153 | } | |
2154 | ||
cd95302d | 2155 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2156 | { |
8e18257d PZ |
2157 | #if SOFTIRQ_VERBOSE |
2158 | return class_filter(class); | |
2159 | #endif | |
2160 | return 0; | |
fbb9ce95 IM |
2161 | } |
2162 | ||
cd95302d | 2163 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2164 | { |
2165 | #if RECLAIM_VERBOSE | |
2166 | return class_filter(class); | |
2167 | #endif | |
2168 | return 0; | |
2169 | } | |
2170 | ||
fbb9ce95 IM |
2171 | #define STRICT_READ_CHECKS 1 |
2172 | ||
cd95302d PZ |
2173 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2174 | #define LOCKDEP_STATE(__STATE) \ | |
2175 | __STATE##_verbose, | |
2176 | #include "lockdep_states.h" | |
2177 | #undef LOCKDEP_STATE | |
2178 | }; | |
2179 | ||
2180 | static inline int state_verbose(enum lock_usage_bit bit, | |
2181 | struct lock_class *class) | |
2182 | { | |
2183 | return state_verbose_f[bit >> 2](class); | |
2184 | } | |
2185 | ||
42c50d54 PZ |
2186 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2187 | enum lock_usage_bit bit, const char *name); | |
2188 | ||
6a6904d3 | 2189 | static int |
1c21f14e PZ |
2190 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2191 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2192 | { |
f989209e | 2193 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2194 | int read = new_bit & 1; |
42c50d54 PZ |
2195 | int dir = new_bit & 2; |
2196 | ||
38aa2714 PZ |
2197 | /* |
2198 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2199 | * has ENABLED state, which would allow recursion deadlocks. | |
2200 | * | |
2201 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2202 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2203 | */ | |
42c50d54 PZ |
2204 | check_usage_f usage = dir ? |
2205 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2206 | |
38aa2714 PZ |
2207 | /* |
2208 | * Validate that this particular lock does not have conflicting | |
2209 | * usage states. | |
2210 | */ | |
6a6904d3 PZ |
2211 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2212 | return 0; | |
42c50d54 | 2213 | |
38aa2714 PZ |
2214 | /* |
2215 | * Validate that the lock dependencies don't have conflicting usage | |
2216 | * states. | |
2217 | */ | |
2218 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2219 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2220 | return 0; |
780e820b | 2221 | |
38aa2714 PZ |
2222 | /* |
2223 | * Check for read in write conflicts | |
2224 | */ | |
2225 | if (!read) { | |
2226 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2227 | return 0; | |
2228 | ||
2229 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2230 | !usage(curr, this, excl_bit + 1, |
2231 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2232 | return 0; |
2233 | } | |
780e820b | 2234 | |
cd95302d | 2235 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2236 | return 2; |
2237 | ||
2238 | return 1; | |
2239 | } | |
2240 | ||
cf40bd16 | 2241 | enum mark_type { |
36bfb9bb PZ |
2242 | #define LOCKDEP_STATE(__STATE) __STATE, |
2243 | #include "lockdep_states.h" | |
2244 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2245 | }; |
2246 | ||
fbb9ce95 IM |
2247 | /* |
2248 | * Mark all held locks with a usage bit: | |
2249 | */ | |
1d09daa5 | 2250 | static int |
cf40bd16 | 2251 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2252 | { |
2253 | enum lock_usage_bit usage_bit; | |
2254 | struct held_lock *hlock; | |
2255 | int i; | |
2256 | ||
2257 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2258 | hlock = curr->held_locks + i; | |
2259 | ||
cf2ad4d1 PZ |
2260 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2261 | if (hlock->read) | |
2262 | usage_bit += 1; /* READ */ | |
2263 | ||
2264 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2265 | |
4ff773bb | 2266 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2267 | return 0; |
2268 | } | |
2269 | ||
2270 | return 1; | |
2271 | } | |
2272 | ||
2273 | /* | |
2274 | * Debugging helper: via this flag we know that we are in | |
2275 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2276 | */ | |
2277 | static int early_boot_irqs_enabled; | |
2278 | ||
2279 | void early_boot_irqs_off(void) | |
2280 | { | |
2281 | early_boot_irqs_enabled = 0; | |
2282 | } | |
2283 | ||
2284 | void early_boot_irqs_on(void) | |
2285 | { | |
2286 | early_boot_irqs_enabled = 1; | |
2287 | } | |
2288 | ||
2289 | /* | |
2290 | * Hardirqs will be enabled: | |
2291 | */ | |
6afe40b4 | 2292 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2293 | { |
2294 | struct task_struct *curr = current; | |
fbb9ce95 | 2295 | |
6afe40b4 | 2296 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2297 | |
fbb9ce95 IM |
2298 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2299 | return; | |
2300 | ||
2301 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2302 | return; | |
2303 | ||
2304 | if (unlikely(curr->hardirqs_enabled)) { | |
2305 | debug_atomic_inc(&redundant_hardirqs_on); | |
2306 | return; | |
2307 | } | |
2308 | /* we'll do an OFF -> ON transition: */ | |
2309 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2310 | |
2311 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2312 | return; | |
2313 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2314 | return; | |
2315 | /* | |
2316 | * We are going to turn hardirqs on, so set the | |
2317 | * usage bit for all held locks: | |
2318 | */ | |
cf40bd16 | 2319 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2320 | return; |
2321 | /* | |
2322 | * If we have softirqs enabled, then set the usage | |
2323 | * bit for all held locks. (disabled hardirqs prevented | |
2324 | * this bit from being set before) | |
2325 | */ | |
2326 | if (curr->softirqs_enabled) | |
cf40bd16 | 2327 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2328 | return; |
2329 | ||
8e18257d PZ |
2330 | curr->hardirq_enable_ip = ip; |
2331 | curr->hardirq_enable_event = ++curr->irq_events; | |
2332 | debug_atomic_inc(&hardirqs_on_events); | |
2333 | } | |
81d68a96 | 2334 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2335 | |
1d09daa5 | 2336 | void trace_hardirqs_on(void) |
81d68a96 SR |
2337 | { |
2338 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2339 | } | |
8e18257d PZ |
2340 | EXPORT_SYMBOL(trace_hardirqs_on); |
2341 | ||
2342 | /* | |
2343 | * Hardirqs were disabled: | |
2344 | */ | |
6afe40b4 | 2345 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2346 | { |
2347 | struct task_struct *curr = current; | |
2348 | ||
6afe40b4 | 2349 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2350 | |
8e18257d PZ |
2351 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2352 | return; | |
2353 | ||
2354 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2355 | return; | |
2356 | ||
2357 | if (curr->hardirqs_enabled) { | |
2358 | /* | |
2359 | * We have done an ON -> OFF transition: | |
2360 | */ | |
2361 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2362 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2363 | curr->hardirq_disable_event = ++curr->irq_events; |
2364 | debug_atomic_inc(&hardirqs_off_events); | |
2365 | } else | |
2366 | debug_atomic_inc(&redundant_hardirqs_off); | |
2367 | } | |
81d68a96 | 2368 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2369 | |
1d09daa5 | 2370 | void trace_hardirqs_off(void) |
81d68a96 SR |
2371 | { |
2372 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2373 | } | |
8e18257d PZ |
2374 | EXPORT_SYMBOL(trace_hardirqs_off); |
2375 | ||
2376 | /* | |
2377 | * Softirqs will be enabled: | |
2378 | */ | |
2379 | void trace_softirqs_on(unsigned long ip) | |
2380 | { | |
2381 | struct task_struct *curr = current; | |
2382 | ||
2383 | if (unlikely(!debug_locks)) | |
2384 | return; | |
2385 | ||
2386 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2387 | return; | |
2388 | ||
2389 | if (curr->softirqs_enabled) { | |
2390 | debug_atomic_inc(&redundant_softirqs_on); | |
2391 | return; | |
2392 | } | |
2393 | ||
2394 | /* | |
2395 | * We'll do an OFF -> ON transition: | |
2396 | */ | |
2397 | curr->softirqs_enabled = 1; | |
2398 | curr->softirq_enable_ip = ip; | |
2399 | curr->softirq_enable_event = ++curr->irq_events; | |
2400 | debug_atomic_inc(&softirqs_on_events); | |
2401 | /* | |
2402 | * We are going to turn softirqs on, so set the | |
2403 | * usage bit for all held locks, if hardirqs are | |
2404 | * enabled too: | |
2405 | */ | |
2406 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2407 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2408 | } |
2409 | ||
2410 | /* | |
2411 | * Softirqs were disabled: | |
2412 | */ | |
2413 | void trace_softirqs_off(unsigned long ip) | |
2414 | { | |
2415 | struct task_struct *curr = current; | |
2416 | ||
2417 | if (unlikely(!debug_locks)) | |
2418 | return; | |
2419 | ||
2420 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2421 | return; | |
2422 | ||
2423 | if (curr->softirqs_enabled) { | |
2424 | /* | |
2425 | * We have done an ON -> OFF transition: | |
2426 | */ | |
2427 | curr->softirqs_enabled = 0; | |
2428 | curr->softirq_disable_ip = ip; | |
2429 | curr->softirq_disable_event = ++curr->irq_events; | |
2430 | debug_atomic_inc(&softirqs_off_events); | |
2431 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2432 | } else | |
2433 | debug_atomic_inc(&redundant_softirqs_off); | |
2434 | } | |
2435 | ||
2f850181 | 2436 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2437 | { |
2438 | struct task_struct *curr = current; | |
2439 | ||
2440 | if (unlikely(!debug_locks)) | |
2441 | return; | |
2442 | ||
2443 | /* no reclaim without waiting on it */ | |
2444 | if (!(gfp_mask & __GFP_WAIT)) | |
2445 | return; | |
2446 | ||
2447 | /* this guy won't enter reclaim */ | |
2448 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2449 | return; | |
2450 | ||
2451 | /* We're only interested __GFP_FS allocations for now */ | |
2452 | if (!(gfp_mask & __GFP_FS)) | |
2453 | return; | |
2454 | ||
2f850181 | 2455 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2456 | return; |
2457 | ||
2458 | mark_held_locks(curr, RECLAIM_FS); | |
2459 | } | |
2460 | ||
2f850181 PZ |
2461 | static void check_flags(unsigned long flags); |
2462 | ||
2463 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2464 | { | |
2465 | unsigned long flags; | |
2466 | ||
2467 | if (unlikely(current->lockdep_recursion)) | |
2468 | return; | |
2469 | ||
2470 | raw_local_irq_save(flags); | |
2471 | check_flags(flags); | |
2472 | current->lockdep_recursion = 1; | |
2473 | __lockdep_trace_alloc(gfp_mask, flags); | |
2474 | current->lockdep_recursion = 0; | |
2475 | raw_local_irq_restore(flags); | |
2476 | } | |
2477 | ||
8e18257d PZ |
2478 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2479 | { | |
2480 | /* | |
2481 | * If non-trylock use in a hardirq or softirq context, then | |
2482 | * mark the lock as used in these contexts: | |
2483 | */ | |
2484 | if (!hlock->trylock) { | |
2485 | if (hlock->read) { | |
2486 | if (curr->hardirq_context) | |
2487 | if (!mark_lock(curr, hlock, | |
2488 | LOCK_USED_IN_HARDIRQ_READ)) | |
2489 | return 0; | |
2490 | if (curr->softirq_context) | |
2491 | if (!mark_lock(curr, hlock, | |
2492 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2493 | return 0; | |
2494 | } else { | |
2495 | if (curr->hardirq_context) | |
2496 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2497 | return 0; | |
2498 | if (curr->softirq_context) | |
2499 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2500 | return 0; | |
2501 | } | |
2502 | } | |
2503 | if (!hlock->hardirqs_off) { | |
2504 | if (hlock->read) { | |
2505 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2506 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2507 | return 0; |
2508 | if (curr->softirqs_enabled) | |
2509 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2510 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2511 | return 0; |
2512 | } else { | |
2513 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2514 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2515 | return 0; |
2516 | if (curr->softirqs_enabled) | |
2517 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2518 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2519 | return 0; |
2520 | } | |
2521 | } | |
2522 | ||
cf40bd16 NP |
2523 | /* |
2524 | * We reuse the irq context infrastructure more broadly as a general | |
2525 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2526 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2527 | * allocation). | |
2528 | */ | |
2529 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2530 | if (hlock->read) { | |
2531 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2532 | return 0; | |
2533 | } else { | |
2534 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2535 | return 0; | |
2536 | } | |
2537 | } | |
2538 | ||
8e18257d PZ |
2539 | return 1; |
2540 | } | |
2541 | ||
2542 | static int separate_irq_context(struct task_struct *curr, | |
2543 | struct held_lock *hlock) | |
2544 | { | |
2545 | unsigned int depth = curr->lockdep_depth; | |
2546 | ||
2547 | /* | |
2548 | * Keep track of points where we cross into an interrupt context: | |
2549 | */ | |
2550 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2551 | curr->softirq_context; | |
2552 | if (depth) { | |
2553 | struct held_lock *prev_hlock; | |
2554 | ||
2555 | prev_hlock = curr->held_locks + depth-1; | |
2556 | /* | |
2557 | * If we cross into another context, reset the | |
2558 | * hash key (this also prevents the checking and the | |
2559 | * adding of the dependency to 'prev'): | |
2560 | */ | |
2561 | if (prev_hlock->irq_context != hlock->irq_context) | |
2562 | return 1; | |
2563 | } | |
2564 | return 0; | |
fbb9ce95 IM |
2565 | } |
2566 | ||
8e18257d | 2567 | #else |
fbb9ce95 | 2568 | |
8e18257d PZ |
2569 | static inline |
2570 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2571 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2572 | { |
8e18257d PZ |
2573 | WARN_ON(1); |
2574 | return 1; | |
2575 | } | |
fbb9ce95 | 2576 | |
8e18257d PZ |
2577 | static inline int mark_irqflags(struct task_struct *curr, |
2578 | struct held_lock *hlock) | |
2579 | { | |
2580 | return 1; | |
2581 | } | |
fbb9ce95 | 2582 | |
8e18257d PZ |
2583 | static inline int separate_irq_context(struct task_struct *curr, |
2584 | struct held_lock *hlock) | |
2585 | { | |
2586 | return 0; | |
fbb9ce95 IM |
2587 | } |
2588 | ||
868a23a8 PZ |
2589 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2590 | { | |
2591 | } | |
2592 | ||
8e18257d | 2593 | #endif |
fbb9ce95 IM |
2594 | |
2595 | /* | |
8e18257d | 2596 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2597 | */ |
1d09daa5 | 2598 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2599 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2600 | { |
8e18257d | 2601 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2602 | |
2603 | /* | |
8e18257d PZ |
2604 | * If already set then do not dirty the cacheline, |
2605 | * nor do any checks: | |
fbb9ce95 | 2606 | */ |
f82b217e | 2607 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2608 | return 1; |
2609 | ||
2610 | if (!graph_lock()) | |
2611 | return 0; | |
fbb9ce95 | 2612 | /* |
8e18257d | 2613 | * Make sure we didnt race: |
fbb9ce95 | 2614 | */ |
f82b217e | 2615 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2616 | graph_unlock(); |
2617 | return 1; | |
2618 | } | |
fbb9ce95 | 2619 | |
f82b217e | 2620 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2621 | |
f82b217e | 2622 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2623 | return 0; |
fbb9ce95 | 2624 | |
8e18257d | 2625 | switch (new_bit) { |
5346417e PZ |
2626 | #define LOCKDEP_STATE(__STATE) \ |
2627 | case LOCK_USED_IN_##__STATE: \ | |
2628 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2629 | case LOCK_ENABLED_##__STATE: \ | |
2630 | case LOCK_ENABLED_##__STATE##_READ: | |
2631 | #include "lockdep_states.h" | |
2632 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2633 | ret = mark_lock_irq(curr, this, new_bit); |
2634 | if (!ret) | |
2635 | return 0; | |
2636 | break; | |
2637 | case LOCK_USED: | |
8e18257d PZ |
2638 | debug_atomic_dec(&nr_unused_locks); |
2639 | break; | |
2640 | default: | |
2641 | if (!debug_locks_off_graph_unlock()) | |
2642 | return 0; | |
2643 | WARN_ON(1); | |
2644 | return 0; | |
2645 | } | |
fbb9ce95 | 2646 | |
8e18257d PZ |
2647 | graph_unlock(); |
2648 | ||
2649 | /* | |
2650 | * We must printk outside of the graph_lock: | |
2651 | */ | |
2652 | if (ret == 2) { | |
2653 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2654 | print_lock(this); | |
2655 | print_irqtrace_events(curr); | |
2656 | dump_stack(); | |
2657 | } | |
2658 | ||
2659 | return ret; | |
2660 | } | |
fbb9ce95 IM |
2661 | |
2662 | /* | |
2663 | * Initialize a lock instance's lock-class mapping info: | |
2664 | */ | |
2665 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2666 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2667 | { |
c8a25005 PZ |
2668 | lock->class_cache = NULL; |
2669 | #ifdef CONFIG_LOCK_STAT | |
2670 | lock->cpu = raw_smp_processor_id(); | |
2671 | #endif | |
2672 | ||
2673 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2674 | lock->name = "NULL"; | |
fbb9ce95 | 2675 | return; |
c8a25005 PZ |
2676 | } |
2677 | ||
2678 | lock->name = name; | |
fbb9ce95 IM |
2679 | |
2680 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2681 | return; | |
fbb9ce95 IM |
2682 | /* |
2683 | * Sanity check, the lock-class key must be persistent: | |
2684 | */ | |
2685 | if (!static_obj(key)) { | |
2686 | printk("BUG: key %p not in .data!\n", key); | |
2687 | DEBUG_LOCKS_WARN_ON(1); | |
2688 | return; | |
2689 | } | |
fbb9ce95 | 2690 | lock->key = key; |
c8a25005 PZ |
2691 | |
2692 | if (unlikely(!debug_locks)) | |
2693 | return; | |
2694 | ||
4dfbb9d8 PZ |
2695 | if (subclass) |
2696 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2697 | } |
fbb9ce95 IM |
2698 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2699 | ||
2700 | /* | |
2701 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2702 | * We maintain the dependency maps and validate the locking attempt: | |
2703 | */ | |
2704 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2705 | int trylock, int read, int check, int hardirqs_off, | |
7531e2f3 | 2706 | struct lockdep_map *nest_lock, unsigned long ip) |
fbb9ce95 IM |
2707 | { |
2708 | struct task_struct *curr = current; | |
d6d897ce | 2709 | struct lock_class *class = NULL; |
fbb9ce95 | 2710 | struct held_lock *hlock; |
fbb9ce95 IM |
2711 | unsigned int depth, id; |
2712 | int chain_head = 0; | |
2713 | u64 chain_key; | |
2714 | ||
f20786ff PZ |
2715 | if (!prove_locking) |
2716 | check = 1; | |
2717 | ||
fbb9ce95 IM |
2718 | if (unlikely(!debug_locks)) |
2719 | return 0; | |
2720 | ||
2721 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2722 | return 0; | |
2723 | ||
2724 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2725 | debug_locks_off(); | |
2726 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2727 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2728 | dump_stack(); |
fbb9ce95 IM |
2729 | return 0; |
2730 | } | |
2731 | ||
d6d897ce IM |
2732 | if (!subclass) |
2733 | class = lock->class_cache; | |
2734 | /* | |
2735 | * Not cached yet or subclass? | |
2736 | */ | |
fbb9ce95 | 2737 | if (unlikely(!class)) { |
4dfbb9d8 | 2738 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2739 | if (!class) |
2740 | return 0; | |
2741 | } | |
2742 | debug_atomic_inc((atomic_t *)&class->ops); | |
2743 | if (very_verbose(class)) { | |
2744 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2745 | if (class->name_version > 1) | |
2746 | printk("#%d", class->name_version); | |
2747 | printk("\n"); | |
2748 | dump_stack(); | |
2749 | } | |
2750 | ||
2751 | /* | |
2752 | * Add the lock to the list of currently held locks. | |
2753 | * (we dont increase the depth just yet, up until the | |
2754 | * dependency checks are done) | |
2755 | */ | |
2756 | depth = curr->lockdep_depth; | |
2757 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2758 | return 0; | |
2759 | ||
2760 | hlock = curr->held_locks + depth; | |
f82b217e DJ |
2761 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2762 | return 0; | |
2763 | hlock->class_idx = class - lock_classes + 1; | |
fbb9ce95 IM |
2764 | hlock->acquire_ip = ip; |
2765 | hlock->instance = lock; | |
7531e2f3 | 2766 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2767 | hlock->trylock = trylock; |
2768 | hlock->read = read; | |
2769 | hlock->check = check; | |
6951b12a | 2770 | hlock->hardirqs_off = !!hardirqs_off; |
f20786ff PZ |
2771 | #ifdef CONFIG_LOCK_STAT |
2772 | hlock->waittime_stamp = 0; | |
2773 | hlock->holdtime_stamp = sched_clock(); | |
2774 | #endif | |
fbb9ce95 | 2775 | |
8e18257d PZ |
2776 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2777 | return 0; | |
2778 | ||
fbb9ce95 | 2779 | /* mark it as used: */ |
4ff773bb | 2780 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2781 | return 0; |
8e18257d | 2782 | |
fbb9ce95 | 2783 | /* |
17aacfb9 | 2784 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2785 | * lock keys along the dependency chain. We save the hash value |
2786 | * at every step so that we can get the current hash easily | |
2787 | * after unlock. The chain hash is then used to cache dependency | |
2788 | * results. | |
2789 | * | |
2790 | * The 'key ID' is what is the most compact key value to drive | |
2791 | * the hash, not class->key. | |
2792 | */ | |
2793 | id = class - lock_classes; | |
2794 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2795 | return 0; | |
2796 | ||
2797 | chain_key = curr->curr_chain_key; | |
2798 | if (!depth) { | |
2799 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2800 | return 0; | |
2801 | chain_head = 1; | |
2802 | } | |
2803 | ||
2804 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2805 | if (separate_irq_context(curr, hlock)) { |
2806 | chain_key = 0; | |
2807 | chain_head = 1; | |
fbb9ce95 | 2808 | } |
fbb9ce95 | 2809 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2810 | |
3aa416b0 | 2811 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2812 | return 0; |
381a2292 | 2813 | |
3aa416b0 | 2814 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2815 | curr->lockdep_depth++; |
2816 | check_chain_key(curr); | |
60e114d1 JP |
2817 | #ifdef CONFIG_DEBUG_LOCKDEP |
2818 | if (unlikely(!debug_locks)) | |
2819 | return 0; | |
2820 | #endif | |
fbb9ce95 IM |
2821 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2822 | debug_locks_off(); | |
2823 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2824 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2825 | dump_stack(); |
fbb9ce95 IM |
2826 | return 0; |
2827 | } | |
381a2292 | 2828 | |
fbb9ce95 IM |
2829 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2830 | max_lockdep_depth = curr->lockdep_depth; | |
2831 | ||
2832 | return 1; | |
2833 | } | |
2834 | ||
2835 | static int | |
2836 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2837 | unsigned long ip) | |
2838 | { | |
2839 | if (!debug_locks_off()) | |
2840 | return 0; | |
2841 | if (debug_locks_silent) | |
2842 | return 0; | |
2843 | ||
2844 | printk("\n=====================================\n"); | |
2845 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2846 | printk( "-------------------------------------\n"); | |
2847 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2848 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2849 | print_lockdep_cache(lock); |
2850 | printk(") at:\n"); | |
2851 | print_ip_sym(ip); | |
2852 | printk("but there are no more locks to release!\n"); | |
2853 | printk("\nother info that might help us debug this:\n"); | |
2854 | lockdep_print_held_locks(curr); | |
2855 | ||
2856 | printk("\nstack backtrace:\n"); | |
2857 | dump_stack(); | |
2858 | ||
2859 | return 0; | |
2860 | } | |
2861 | ||
2862 | /* | |
2863 | * Common debugging checks for both nested and non-nested unlock: | |
2864 | */ | |
2865 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2866 | unsigned long ip) | |
2867 | { | |
2868 | if (unlikely(!debug_locks)) | |
2869 | return 0; | |
2870 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2871 | return 0; | |
2872 | ||
2873 | if (curr->lockdep_depth <= 0) | |
2874 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2875 | ||
2876 | return 1; | |
2877 | } | |
2878 | ||
64aa348e | 2879 | static int |
00ef9f73 PZ |
2880 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2881 | struct lock_class_key *key, unsigned int subclass, | |
2882 | unsigned long ip) | |
64aa348e PZ |
2883 | { |
2884 | struct task_struct *curr = current; | |
2885 | struct held_lock *hlock, *prev_hlock; | |
2886 | struct lock_class *class; | |
2887 | unsigned int depth; | |
2888 | int i; | |
2889 | ||
2890 | depth = curr->lockdep_depth; | |
2891 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2892 | return 0; | |
2893 | ||
2894 | prev_hlock = NULL; | |
2895 | for (i = depth-1; i >= 0; i--) { | |
2896 | hlock = curr->held_locks + i; | |
2897 | /* | |
2898 | * We must not cross into another context: | |
2899 | */ | |
2900 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2901 | break; | |
2902 | if (hlock->instance == lock) | |
2903 | goto found_it; | |
2904 | prev_hlock = hlock; | |
2905 | } | |
2906 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2907 | ||
2908 | found_it: | |
00ef9f73 | 2909 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2910 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2911 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2912 | |
2913 | curr->lockdep_depth = i; | |
2914 | curr->curr_chain_key = hlock->prev_chain_key; | |
2915 | ||
2916 | for (; i < depth; i++) { | |
2917 | hlock = curr->held_locks + i; | |
2918 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2919 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2920 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2921 | hlock->nest_lock, hlock->acquire_ip)) |
64aa348e PZ |
2922 | return 0; |
2923 | } | |
2924 | ||
2925 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2926 | return 0; | |
2927 | return 1; | |
2928 | } | |
2929 | ||
fbb9ce95 IM |
2930 | /* |
2931 | * Remove the lock to the list of currently held locks in a | |
2932 | * potentially non-nested (out of order) manner. This is a | |
2933 | * relatively rare operation, as all the unlock APIs default | |
2934 | * to nested mode (which uses lock_release()): | |
2935 | */ | |
2936 | static int | |
2937 | lock_release_non_nested(struct task_struct *curr, | |
2938 | struct lockdep_map *lock, unsigned long ip) | |
2939 | { | |
2940 | struct held_lock *hlock, *prev_hlock; | |
2941 | unsigned int depth; | |
2942 | int i; | |
2943 | ||
2944 | /* | |
2945 | * Check whether the lock exists in the current stack | |
2946 | * of held locks: | |
2947 | */ | |
2948 | depth = curr->lockdep_depth; | |
2949 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2950 | return 0; | |
2951 | ||
2952 | prev_hlock = NULL; | |
2953 | for (i = depth-1; i >= 0; i--) { | |
2954 | hlock = curr->held_locks + i; | |
2955 | /* | |
2956 | * We must not cross into another context: | |
2957 | */ | |
2958 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2959 | break; | |
2960 | if (hlock->instance == lock) | |
2961 | goto found_it; | |
2962 | prev_hlock = hlock; | |
2963 | } | |
2964 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2965 | ||
2966 | found_it: | |
f20786ff PZ |
2967 | lock_release_holdtime(hlock); |
2968 | ||
fbb9ce95 IM |
2969 | /* |
2970 | * We have the right lock to unlock, 'hlock' points to it. | |
2971 | * Now we remove it from the stack, and add back the other | |
2972 | * entries (if any), recalculating the hash along the way: | |
2973 | */ | |
2974 | curr->lockdep_depth = i; | |
2975 | curr->curr_chain_key = hlock->prev_chain_key; | |
2976 | ||
2977 | for (i++; i < depth; i++) { | |
2978 | hlock = curr->held_locks + i; | |
2979 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2980 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 2981 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2982 | hlock->nest_lock, hlock->acquire_ip)) |
fbb9ce95 IM |
2983 | return 0; |
2984 | } | |
2985 | ||
2986 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2987 | return 0; | |
2988 | return 1; | |
2989 | } | |
2990 | ||
2991 | /* | |
2992 | * Remove the lock to the list of currently held locks - this gets | |
2993 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2994 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2995 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2996 | */ | |
2997 | static int lock_release_nested(struct task_struct *curr, | |
2998 | struct lockdep_map *lock, unsigned long ip) | |
2999 | { | |
3000 | struct held_lock *hlock; | |
3001 | unsigned int depth; | |
3002 | ||
3003 | /* | |
3004 | * Pop off the top of the lock stack: | |
3005 | */ | |
3006 | depth = curr->lockdep_depth - 1; | |
3007 | hlock = curr->held_locks + depth; | |
3008 | ||
3009 | /* | |
3010 | * Is the unlock non-nested: | |
3011 | */ | |
3012 | if (hlock->instance != lock) | |
3013 | return lock_release_non_nested(curr, lock, ip); | |
3014 | curr->lockdep_depth--; | |
3015 | ||
3016 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
3017 | return 0; | |
3018 | ||
3019 | curr->curr_chain_key = hlock->prev_chain_key; | |
3020 | ||
f20786ff PZ |
3021 | lock_release_holdtime(hlock); |
3022 | ||
fbb9ce95 IM |
3023 | #ifdef CONFIG_DEBUG_LOCKDEP |
3024 | hlock->prev_chain_key = 0; | |
f82b217e | 3025 | hlock->class_idx = 0; |
fbb9ce95 IM |
3026 | hlock->acquire_ip = 0; |
3027 | hlock->irq_context = 0; | |
3028 | #endif | |
3029 | return 1; | |
3030 | } | |
3031 | ||
3032 | /* | |
3033 | * Remove the lock to the list of currently held locks - this gets | |
3034 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3035 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3036 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3037 | */ | |
3038 | static void | |
3039 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3040 | { | |
3041 | struct task_struct *curr = current; | |
3042 | ||
3043 | if (!check_unlock(curr, lock, ip)) | |
3044 | return; | |
3045 | ||
3046 | if (nested) { | |
3047 | if (!lock_release_nested(curr, lock, ip)) | |
3048 | return; | |
3049 | } else { | |
3050 | if (!lock_release_non_nested(curr, lock, ip)) | |
3051 | return; | |
3052 | } | |
3053 | ||
3054 | check_chain_key(curr); | |
3055 | } | |
3056 | ||
3057 | /* | |
3058 | * Check whether we follow the irq-flags state precisely: | |
3059 | */ | |
1d09daa5 | 3060 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3061 | { |
992860e9 IM |
3062 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3063 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3064 | if (!debug_locks) |
3065 | return; | |
3066 | ||
5f9fa8a6 IM |
3067 | if (irqs_disabled_flags(flags)) { |
3068 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3069 | printk("possible reason: unannotated irqs-off.\n"); | |
3070 | } | |
3071 | } else { | |
3072 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3073 | printk("possible reason: unannotated irqs-on.\n"); | |
3074 | } | |
3075 | } | |
fbb9ce95 IM |
3076 | |
3077 | /* | |
3078 | * We dont accurately track softirq state in e.g. | |
3079 | * hardirq contexts (such as on 4KSTACKS), so only | |
3080 | * check if not in hardirq contexts: | |
3081 | */ | |
3082 | if (!hardirq_count()) { | |
3083 | if (softirq_count()) | |
3084 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3085 | else | |
3086 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3087 | } | |
3088 | ||
3089 | if (!debug_locks) | |
3090 | print_irqtrace_events(current); | |
3091 | #endif | |
3092 | } | |
3093 | ||
00ef9f73 PZ |
3094 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3095 | struct lock_class_key *key, unsigned int subclass, | |
3096 | unsigned long ip) | |
64aa348e PZ |
3097 | { |
3098 | unsigned long flags; | |
3099 | ||
3100 | if (unlikely(current->lockdep_recursion)) | |
3101 | return; | |
3102 | ||
3103 | raw_local_irq_save(flags); | |
3104 | current->lockdep_recursion = 1; | |
3105 | check_flags(flags); | |
00ef9f73 | 3106 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3107 | check_chain_key(current); |
3108 | current->lockdep_recursion = 0; | |
3109 | raw_local_irq_restore(flags); | |
3110 | } | |
00ef9f73 | 3111 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3112 | |
fbb9ce95 IM |
3113 | /* |
3114 | * We are not always called with irqs disabled - do that here, | |
3115 | * and also avoid lockdep recursion: | |
3116 | */ | |
1d09daa5 | 3117 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3118 | int trylock, int read, int check, |
3119 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3120 | { |
3121 | unsigned long flags; | |
3122 | ||
efed792d PZ |
3123 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
3124 | ||
fbb9ce95 IM |
3125 | if (unlikely(current->lockdep_recursion)) |
3126 | return; | |
3127 | ||
3128 | raw_local_irq_save(flags); | |
3129 | check_flags(flags); | |
3130 | ||
3131 | current->lockdep_recursion = 1; | |
3132 | __lock_acquire(lock, subclass, trylock, read, check, | |
7531e2f3 | 3133 | irqs_disabled_flags(flags), nest_lock, ip); |
fbb9ce95 IM |
3134 | current->lockdep_recursion = 0; |
3135 | raw_local_irq_restore(flags); | |
3136 | } | |
fbb9ce95 IM |
3137 | EXPORT_SYMBOL_GPL(lock_acquire); |
3138 | ||
1d09daa5 | 3139 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3140 | unsigned long ip) |
fbb9ce95 IM |
3141 | { |
3142 | unsigned long flags; | |
3143 | ||
efed792d PZ |
3144 | trace_lock_release(lock, nested, ip); |
3145 | ||
fbb9ce95 IM |
3146 | if (unlikely(current->lockdep_recursion)) |
3147 | return; | |
3148 | ||
3149 | raw_local_irq_save(flags); | |
3150 | check_flags(flags); | |
3151 | current->lockdep_recursion = 1; | |
3152 | __lock_release(lock, nested, ip); | |
3153 | current->lockdep_recursion = 0; | |
3154 | raw_local_irq_restore(flags); | |
3155 | } | |
fbb9ce95 IM |
3156 | EXPORT_SYMBOL_GPL(lock_release); |
3157 | ||
cf40bd16 NP |
3158 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3159 | { | |
3160 | current->lockdep_reclaim_gfp = gfp_mask; | |
3161 | } | |
3162 | ||
3163 | void lockdep_clear_current_reclaim_state(void) | |
3164 | { | |
3165 | current->lockdep_reclaim_gfp = 0; | |
3166 | } | |
3167 | ||
f20786ff PZ |
3168 | #ifdef CONFIG_LOCK_STAT |
3169 | static int | |
3170 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3171 | unsigned long ip) | |
3172 | { | |
3173 | if (!debug_locks_off()) | |
3174 | return 0; | |
3175 | if (debug_locks_silent) | |
3176 | return 0; | |
3177 | ||
3178 | printk("\n=================================\n"); | |
3179 | printk( "[ BUG: bad contention detected! ]\n"); | |
3180 | printk( "---------------------------------\n"); | |
3181 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3182 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3183 | print_lockdep_cache(lock); |
3184 | printk(") at:\n"); | |
3185 | print_ip_sym(ip); | |
3186 | printk("but there are no locks held!\n"); | |
3187 | printk("\nother info that might help us debug this:\n"); | |
3188 | lockdep_print_held_locks(curr); | |
3189 | ||
3190 | printk("\nstack backtrace:\n"); | |
3191 | dump_stack(); | |
3192 | ||
3193 | return 0; | |
3194 | } | |
3195 | ||
3196 | static void | |
3197 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3198 | { | |
3199 | struct task_struct *curr = current; | |
3200 | struct held_lock *hlock, *prev_hlock; | |
3201 | struct lock_class_stats *stats; | |
3202 | unsigned int depth; | |
c7e78cff | 3203 | int i, contention_point, contending_point; |
f20786ff PZ |
3204 | |
3205 | depth = curr->lockdep_depth; | |
3206 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3207 | return; | |
3208 | ||
3209 | prev_hlock = NULL; | |
3210 | for (i = depth-1; i >= 0; i--) { | |
3211 | hlock = curr->held_locks + i; | |
3212 | /* | |
3213 | * We must not cross into another context: | |
3214 | */ | |
3215 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3216 | break; | |
3217 | if (hlock->instance == lock) | |
3218 | goto found_it; | |
3219 | prev_hlock = hlock; | |
3220 | } | |
3221 | print_lock_contention_bug(curr, lock, ip); | |
3222 | return; | |
3223 | ||
3224 | found_it: | |
3225 | hlock->waittime_stamp = sched_clock(); | |
3226 | ||
c7e78cff PZ |
3227 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3228 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3229 | lock->ip); | |
f20786ff | 3230 | |
f82b217e | 3231 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3232 | if (contention_point < LOCKSTAT_POINTS) |
3233 | stats->contention_point[contention_point]++; | |
3234 | if (contending_point < LOCKSTAT_POINTS) | |
3235 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3236 | if (lock->cpu != smp_processor_id()) |
3237 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3238 | put_lock_stats(stats); |
3239 | } | |
3240 | ||
3241 | static void | |
c7e78cff | 3242 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3243 | { |
3244 | struct task_struct *curr = current; | |
3245 | struct held_lock *hlock, *prev_hlock; | |
3246 | struct lock_class_stats *stats; | |
3247 | unsigned int depth; | |
3248 | u64 now; | |
96645678 PZ |
3249 | s64 waittime = 0; |
3250 | int i, cpu; | |
f20786ff PZ |
3251 | |
3252 | depth = curr->lockdep_depth; | |
3253 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3254 | return; | |
3255 | ||
3256 | prev_hlock = NULL; | |
3257 | for (i = depth-1; i >= 0; i--) { | |
3258 | hlock = curr->held_locks + i; | |
3259 | /* | |
3260 | * We must not cross into another context: | |
3261 | */ | |
3262 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3263 | break; | |
3264 | if (hlock->instance == lock) | |
3265 | goto found_it; | |
3266 | prev_hlock = hlock; | |
3267 | } | |
3268 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3269 | return; | |
3270 | ||
3271 | found_it: | |
96645678 PZ |
3272 | cpu = smp_processor_id(); |
3273 | if (hlock->waittime_stamp) { | |
3274 | now = sched_clock(); | |
3275 | waittime = now - hlock->waittime_stamp; | |
3276 | hlock->holdtime_stamp = now; | |
3277 | } | |
f20786ff | 3278 | |
2062501a FW |
3279 | trace_lock_acquired(lock, ip, waittime); |
3280 | ||
f82b217e | 3281 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3282 | if (waittime) { |
3283 | if (hlock->read) | |
3284 | lock_time_inc(&stats->read_waittime, waittime); | |
3285 | else | |
3286 | lock_time_inc(&stats->write_waittime, waittime); | |
3287 | } | |
3288 | if (lock->cpu != cpu) | |
3289 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3290 | put_lock_stats(stats); |
96645678 PZ |
3291 | |
3292 | lock->cpu = cpu; | |
c7e78cff | 3293 | lock->ip = ip; |
f20786ff PZ |
3294 | } |
3295 | ||
3296 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3297 | { | |
3298 | unsigned long flags; | |
3299 | ||
efed792d PZ |
3300 | trace_lock_contended(lock, ip); |
3301 | ||
f20786ff PZ |
3302 | if (unlikely(!lock_stat)) |
3303 | return; | |
3304 | ||
3305 | if (unlikely(current->lockdep_recursion)) | |
3306 | return; | |
3307 | ||
3308 | raw_local_irq_save(flags); | |
3309 | check_flags(flags); | |
3310 | current->lockdep_recursion = 1; | |
3311 | __lock_contended(lock, ip); | |
3312 | current->lockdep_recursion = 0; | |
3313 | raw_local_irq_restore(flags); | |
3314 | } | |
3315 | EXPORT_SYMBOL_GPL(lock_contended); | |
3316 | ||
c7e78cff | 3317 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3318 | { |
3319 | unsigned long flags; | |
3320 | ||
3321 | if (unlikely(!lock_stat)) | |
3322 | return; | |
3323 | ||
3324 | if (unlikely(current->lockdep_recursion)) | |
3325 | return; | |
3326 | ||
3327 | raw_local_irq_save(flags); | |
3328 | check_flags(flags); | |
3329 | current->lockdep_recursion = 1; | |
c7e78cff | 3330 | __lock_acquired(lock, ip); |
f20786ff PZ |
3331 | current->lockdep_recursion = 0; |
3332 | raw_local_irq_restore(flags); | |
3333 | } | |
3334 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3335 | #endif | |
3336 | ||
fbb9ce95 IM |
3337 | /* |
3338 | * Used by the testsuite, sanitize the validator state | |
3339 | * after a simulated failure: | |
3340 | */ | |
3341 | ||
3342 | void lockdep_reset(void) | |
3343 | { | |
3344 | unsigned long flags; | |
23d95a03 | 3345 | int i; |
fbb9ce95 IM |
3346 | |
3347 | raw_local_irq_save(flags); | |
3348 | current->curr_chain_key = 0; | |
3349 | current->lockdep_depth = 0; | |
3350 | current->lockdep_recursion = 0; | |
3351 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3352 | nr_hardirq_chains = 0; | |
3353 | nr_softirq_chains = 0; | |
3354 | nr_process_chains = 0; | |
3355 | debug_locks = 1; | |
23d95a03 IM |
3356 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3357 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3358 | raw_local_irq_restore(flags); |
3359 | } | |
3360 | ||
3361 | static void zap_class(struct lock_class *class) | |
3362 | { | |
3363 | int i; | |
3364 | ||
3365 | /* | |
3366 | * Remove all dependencies this lock is | |
3367 | * involved in: | |
3368 | */ | |
3369 | for (i = 0; i < nr_list_entries; i++) { | |
3370 | if (list_entries[i].class == class) | |
3371 | list_del_rcu(&list_entries[i].entry); | |
3372 | } | |
3373 | /* | |
3374 | * Unhash the class and remove it from the all_lock_classes list: | |
3375 | */ | |
3376 | list_del_rcu(&class->hash_entry); | |
3377 | list_del_rcu(&class->lock_entry); | |
3378 | ||
8bfe0298 | 3379 | class->key = NULL; |
fbb9ce95 IM |
3380 | } |
3381 | ||
fabe874a | 3382 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3383 | { |
3384 | return addr >= start && addr < start + size; | |
3385 | } | |
3386 | ||
3387 | void lockdep_free_key_range(void *start, unsigned long size) | |
3388 | { | |
3389 | struct lock_class *class, *next; | |
3390 | struct list_head *head; | |
3391 | unsigned long flags; | |
3392 | int i; | |
5a26db5b | 3393 | int locked; |
fbb9ce95 IM |
3394 | |
3395 | raw_local_irq_save(flags); | |
5a26db5b | 3396 | locked = graph_lock(); |
fbb9ce95 IM |
3397 | |
3398 | /* | |
3399 | * Unhash all classes that were created by this module: | |
3400 | */ | |
3401 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3402 | head = classhash_table + i; | |
3403 | if (list_empty(head)) | |
3404 | continue; | |
fabe874a | 3405 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3406 | if (within(class->key, start, size)) |
3407 | zap_class(class); | |
fabe874a AV |
3408 | else if (within(class->name, start, size)) |
3409 | zap_class(class); | |
3410 | } | |
fbb9ce95 IM |
3411 | } |
3412 | ||
5a26db5b NP |
3413 | if (locked) |
3414 | graph_unlock(); | |
fbb9ce95 IM |
3415 | raw_local_irq_restore(flags); |
3416 | } | |
3417 | ||
3418 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3419 | { | |
d6d897ce | 3420 | struct lock_class *class, *next; |
fbb9ce95 IM |
3421 | struct list_head *head; |
3422 | unsigned long flags; | |
3423 | int i, j; | |
5a26db5b | 3424 | int locked; |
fbb9ce95 IM |
3425 | |
3426 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3427 | |
3428 | /* | |
d6d897ce IM |
3429 | * Remove all classes this lock might have: |
3430 | */ | |
3431 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3432 | /* | |
3433 | * If the class exists we look it up and zap it: | |
3434 | */ | |
3435 | class = look_up_lock_class(lock, j); | |
3436 | if (class) | |
3437 | zap_class(class); | |
3438 | } | |
3439 | /* | |
3440 | * Debug check: in the end all mapped classes should | |
3441 | * be gone. | |
fbb9ce95 | 3442 | */ |
5a26db5b | 3443 | locked = graph_lock(); |
fbb9ce95 IM |
3444 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3445 | head = classhash_table + i; | |
3446 | if (list_empty(head)) | |
3447 | continue; | |
3448 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3449 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3450 | if (debug_locks_off_graph_unlock()) |
3451 | WARN_ON(1); | |
d6d897ce | 3452 | goto out_restore; |
fbb9ce95 IM |
3453 | } |
3454 | } | |
3455 | } | |
5a26db5b NP |
3456 | if (locked) |
3457 | graph_unlock(); | |
d6d897ce IM |
3458 | |
3459 | out_restore: | |
fbb9ce95 IM |
3460 | raw_local_irq_restore(flags); |
3461 | } | |
3462 | ||
1499993c | 3463 | void lockdep_init(void) |
fbb9ce95 IM |
3464 | { |
3465 | int i; | |
3466 | ||
3467 | /* | |
3468 | * Some architectures have their own start_kernel() | |
3469 | * code which calls lockdep_init(), while we also | |
3470 | * call lockdep_init() from the start_kernel() itself, | |
3471 | * and we want to initialize the hashes only once: | |
3472 | */ | |
3473 | if (lockdep_initialized) | |
3474 | return; | |
3475 | ||
3476 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3477 | INIT_LIST_HEAD(classhash_table + i); | |
3478 | ||
3479 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3480 | INIT_LIST_HEAD(chainhash_table + i); | |
3481 | ||
3482 | lockdep_initialized = 1; | |
3483 | } | |
3484 | ||
3485 | void __init lockdep_info(void) | |
3486 | { | |
3487 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3488 | ||
b0788caf | 3489 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3490 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3491 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3492 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3493 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3494 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3495 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3496 | ||
3497 | printk(" memory used by lock dependency info: %lu kB\n", | |
3498 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3499 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3500 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3501 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
4dd861d6 ML |
3502 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024 |
3503 | #ifdef CONFIG_PROVE_LOCKING | |
3504 | + sizeof(struct circular_queue) + sizeof(bfs_accessed) | |
3505 | #endif | |
3506 | ); | |
fbb9ce95 IM |
3507 | |
3508 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3509 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3510 | ||
3511 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3512 | if (lockdep_init_error) { |
3513 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3514 | printk("Call stack leading to lockdep invocation was:\n"); | |
3515 | print_stack_trace(&lockdep_init_trace, 0); | |
3516 | } | |
fbb9ce95 IM |
3517 | #endif |
3518 | } | |
3519 | ||
fbb9ce95 IM |
3520 | static void |
3521 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3522 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3523 | { |
3524 | if (!debug_locks_off()) | |
3525 | return; | |
3526 | if (debug_locks_silent) | |
3527 | return; | |
3528 | ||
3529 | printk("\n=========================\n"); | |
3530 | printk( "[ BUG: held lock freed! ]\n"); | |
3531 | printk( "-------------------------\n"); | |
3532 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3533 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3534 | print_lock(hlock); |
fbb9ce95 IM |
3535 | lockdep_print_held_locks(curr); |
3536 | ||
3537 | printk("\nstack backtrace:\n"); | |
3538 | dump_stack(); | |
3539 | } | |
3540 | ||
54561783 ON |
3541 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3542 | const void* lock_from, unsigned long lock_len) | |
3543 | { | |
3544 | return lock_from + lock_len <= mem_from || | |
3545 | mem_from + mem_len <= lock_from; | |
3546 | } | |
3547 | ||
fbb9ce95 IM |
3548 | /* |
3549 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3550 | * is destroyed or reinitialized - this code checks whether there is | |
3551 | * any held lock in the memory range of <from> to <to>: | |
3552 | */ | |
3553 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3554 | { | |
fbb9ce95 IM |
3555 | struct task_struct *curr = current; |
3556 | struct held_lock *hlock; | |
3557 | unsigned long flags; | |
3558 | int i; | |
3559 | ||
3560 | if (unlikely(!debug_locks)) | |
3561 | return; | |
3562 | ||
3563 | local_irq_save(flags); | |
3564 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3565 | hlock = curr->held_locks + i; | |
3566 | ||
54561783 ON |
3567 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3568 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3569 | continue; |
3570 | ||
54561783 | 3571 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3572 | break; |
3573 | } | |
3574 | local_irq_restore(flags); | |
3575 | } | |
ed07536e | 3576 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3577 | |
3578 | static void print_held_locks_bug(struct task_struct *curr) | |
3579 | { | |
3580 | if (!debug_locks_off()) | |
3581 | return; | |
3582 | if (debug_locks_silent) | |
3583 | return; | |
3584 | ||
3585 | printk("\n=====================================\n"); | |
3586 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3587 | printk( "-------------------------------------\n"); | |
3588 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3589 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3590 | lockdep_print_held_locks(curr); |
3591 | ||
3592 | printk("\nstack backtrace:\n"); | |
3593 | dump_stack(); | |
3594 | } | |
3595 | ||
3596 | void debug_check_no_locks_held(struct task_struct *task) | |
3597 | { | |
3598 | if (unlikely(task->lockdep_depth > 0)) | |
3599 | print_held_locks_bug(task); | |
3600 | } | |
3601 | ||
3602 | void debug_show_all_locks(void) | |
3603 | { | |
3604 | struct task_struct *g, *p; | |
3605 | int count = 10; | |
3606 | int unlock = 1; | |
3607 | ||
9c35dd7f JP |
3608 | if (unlikely(!debug_locks)) { |
3609 | printk("INFO: lockdep is turned off.\n"); | |
3610 | return; | |
3611 | } | |
fbb9ce95 IM |
3612 | printk("\nShowing all locks held in the system:\n"); |
3613 | ||
3614 | /* | |
3615 | * Here we try to get the tasklist_lock as hard as possible, | |
3616 | * if not successful after 2 seconds we ignore it (but keep | |
3617 | * trying). This is to enable a debug printout even if a | |
3618 | * tasklist_lock-holding task deadlocks or crashes. | |
3619 | */ | |
3620 | retry: | |
3621 | if (!read_trylock(&tasklist_lock)) { | |
3622 | if (count == 10) | |
3623 | printk("hm, tasklist_lock locked, retrying... "); | |
3624 | if (count) { | |
3625 | count--; | |
3626 | printk(" #%d", 10-count); | |
3627 | mdelay(200); | |
3628 | goto retry; | |
3629 | } | |
3630 | printk(" ignoring it.\n"); | |
3631 | unlock = 0; | |
46fec7ac | 3632 | } else { |
3633 | if (count != 10) | |
3634 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3635 | } |
fbb9ce95 IM |
3636 | |
3637 | do_each_thread(g, p) { | |
85684873 IM |
3638 | /* |
3639 | * It's not reliable to print a task's held locks | |
3640 | * if it's not sleeping (or if it's not the current | |
3641 | * task): | |
3642 | */ | |
3643 | if (p->state == TASK_RUNNING && p != current) | |
3644 | continue; | |
fbb9ce95 IM |
3645 | if (p->lockdep_depth) |
3646 | lockdep_print_held_locks(p); | |
3647 | if (!unlock) | |
3648 | if (read_trylock(&tasklist_lock)) | |
3649 | unlock = 1; | |
3650 | } while_each_thread(g, p); | |
3651 | ||
3652 | printk("\n"); | |
3653 | printk("=============================================\n\n"); | |
3654 | ||
3655 | if (unlock) | |
3656 | read_unlock(&tasklist_lock); | |
3657 | } | |
fbb9ce95 IM |
3658 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3659 | ||
82a1fcb9 IM |
3660 | /* |
3661 | * Careful: only use this function if you are sure that | |
3662 | * the task cannot run in parallel! | |
3663 | */ | |
3664 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3665 | { |
9c35dd7f JP |
3666 | if (unlikely(!debug_locks)) { |
3667 | printk("INFO: lockdep is turned off.\n"); | |
3668 | return; | |
3669 | } | |
fbb9ce95 IM |
3670 | lockdep_print_held_locks(task); |
3671 | } | |
82a1fcb9 IM |
3672 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3673 | ||
3674 | void debug_show_held_locks(struct task_struct *task) | |
3675 | { | |
3676 | __debug_show_held_locks(task); | |
3677 | } | |
fbb9ce95 | 3678 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3679 | |
3680 | void lockdep_sys_exit(void) | |
3681 | { | |
3682 | struct task_struct *curr = current; | |
3683 | ||
3684 | if (unlikely(curr->lockdep_depth)) { | |
3685 | if (!debug_locks_off()) | |
3686 | return; | |
3687 | printk("\n================================================\n"); | |
3688 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3689 | printk( "------------------------------------------------\n"); | |
3690 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3691 | curr->comm, curr->pid); | |
3692 | lockdep_print_held_locks(curr); | |
3693 | } | |
3694 | } |