Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 | 8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
90eec103 | 9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra |
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> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
d3d03d4f | 47 | #include <linux/kmemcheck.h> |
e7904a28 | 48 | #include <linux/random.h> |
dfaaf3fa | 49 | #include <linux/jhash.h> |
af012961 | 50 | |
fbb9ce95 IM |
51 | #include <asm/sections.h> |
52 | ||
53 | #include "lockdep_internals.h" | |
54 | ||
a8d154b0 | 55 | #define CREATE_TRACE_POINTS |
67178767 | 56 | #include <trace/events/lock.h> |
a8d154b0 | 57 | |
f20786ff PZ |
58 | #ifdef CONFIG_PROVE_LOCKING |
59 | int prove_locking = 1; | |
60 | module_param(prove_locking, int, 0644); | |
61 | #else | |
62 | #define prove_locking 0 | |
63 | #endif | |
64 | ||
65 | #ifdef CONFIG_LOCK_STAT | |
66 | int lock_stat = 1; | |
67 | module_param(lock_stat, int, 0644); | |
68 | #else | |
69 | #define lock_stat 0 | |
70 | #endif | |
71 | ||
fbb9ce95 | 72 | /* |
74c383f1 IM |
73 | * lockdep_lock: protects the lockdep graph, the hashes and the |
74 | * class/list/hash allocators. | |
fbb9ce95 IM |
75 | * |
76 | * This is one of the rare exceptions where it's justified | |
77 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 78 | * code to recurse back into the lockdep code... |
fbb9ce95 | 79 | */ |
edc35bd7 | 80 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
81 | |
82 | static int graph_lock(void) | |
83 | { | |
0199c4e6 | 84 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
85 | /* |
86 | * Make sure that if another CPU detected a bug while | |
87 | * walking the graph we dont change it (while the other | |
88 | * CPU is busy printing out stuff with the graph lock | |
89 | * dropped already) | |
90 | */ | |
91 | if (!debug_locks) { | |
0199c4e6 | 92 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
93 | return 0; |
94 | } | |
bb065afb SR |
95 | /* prevent any recursions within lockdep from causing deadlocks */ |
96 | current->lockdep_recursion++; | |
74c383f1 IM |
97 | return 1; |
98 | } | |
99 | ||
100 | static inline int graph_unlock(void) | |
101 | { | |
0119fee4 PZ |
102 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
103 | /* | |
104 | * The lockdep graph lock isn't locked while we expect it to | |
105 | * be, we're confused now, bye! | |
106 | */ | |
381a2292 | 107 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 108 | } |
381a2292 | 109 | |
bb065afb | 110 | current->lockdep_recursion--; |
0199c4e6 | 111 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
112 | return 0; |
113 | } | |
114 | ||
115 | /* | |
116 | * Turn lock debugging off and return with 0 if it was off already, | |
117 | * and also release the graph lock: | |
118 | */ | |
119 | static inline int debug_locks_off_graph_unlock(void) | |
120 | { | |
121 | int ret = debug_locks_off(); | |
122 | ||
0199c4e6 | 123 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
124 | |
125 | return ret; | |
126 | } | |
fbb9ce95 | 127 | |
fbb9ce95 | 128 | unsigned long nr_list_entries; |
af012961 | 129 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 130 | |
fbb9ce95 IM |
131 | /* |
132 | * All data structures here are protected by the global debug_lock. | |
133 | * | |
134 | * Mutex key structs only get allocated, once during bootup, and never | |
135 | * get freed - this significantly simplifies the debugging code. | |
136 | */ | |
137 | unsigned long nr_lock_classes; | |
138 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
139 | ||
f82b217e DJ |
140 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
141 | { | |
142 | if (!hlock->class_idx) { | |
0119fee4 PZ |
143 | /* |
144 | * Someone passed in garbage, we give up. | |
145 | */ | |
f82b217e DJ |
146 | DEBUG_LOCKS_WARN_ON(1); |
147 | return NULL; | |
148 | } | |
149 | return lock_classes + hlock->class_idx - 1; | |
150 | } | |
151 | ||
f20786ff | 152 | #ifdef CONFIG_LOCK_STAT |
25528213 | 153 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
f20786ff | 154 | |
3365e779 PZ |
155 | static inline u64 lockstat_clock(void) |
156 | { | |
c676329a | 157 | return local_clock(); |
3365e779 PZ |
158 | } |
159 | ||
c7e78cff | 160 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
161 | { |
162 | int i; | |
163 | ||
c7e78cff PZ |
164 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
165 | if (points[i] == 0) { | |
166 | points[i] = ip; | |
f20786ff PZ |
167 | break; |
168 | } | |
c7e78cff | 169 | if (points[i] == ip) |
f20786ff PZ |
170 | break; |
171 | } | |
172 | ||
173 | return i; | |
174 | } | |
175 | ||
3365e779 | 176 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
177 | { |
178 | if (time > lt->max) | |
179 | lt->max = time; | |
180 | ||
109d71c6 | 181 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
182 | lt->min = time; |
183 | ||
184 | lt->total += time; | |
185 | lt->nr++; | |
186 | } | |
187 | ||
c46261de PZ |
188 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
189 | { | |
109d71c6 FR |
190 | if (!src->nr) |
191 | return; | |
192 | ||
193 | if (src->max > dst->max) | |
194 | dst->max = src->max; | |
195 | ||
196 | if (src->min < dst->min || !dst->nr) | |
197 | dst->min = src->min; | |
198 | ||
c46261de PZ |
199 | dst->total += src->total; |
200 | dst->nr += src->nr; | |
201 | } | |
202 | ||
203 | struct lock_class_stats lock_stats(struct lock_class *class) | |
204 | { | |
205 | struct lock_class_stats stats; | |
206 | int cpu, i; | |
207 | ||
208 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
209 | for_each_possible_cpu(cpu) { | |
210 | struct lock_class_stats *pcs = | |
1871e52c | 211 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
212 | |
213 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
214 | stats.contention_point[i] += pcs->contention_point[i]; | |
215 | ||
c7e78cff PZ |
216 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
217 | stats.contending_point[i] += pcs->contending_point[i]; | |
218 | ||
c46261de PZ |
219 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
220 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
221 | ||
222 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
223 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
224 | |
225 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
226 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
227 | } |
228 | ||
229 | return stats; | |
230 | } | |
231 | ||
232 | void clear_lock_stats(struct lock_class *class) | |
233 | { | |
234 | int cpu; | |
235 | ||
236 | for_each_possible_cpu(cpu) { | |
237 | struct lock_class_stats *cpu_stats = | |
1871e52c | 238 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
239 | |
240 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
241 | } | |
242 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 243 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
244 | } |
245 | ||
f20786ff PZ |
246 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
247 | { | |
1871e52c | 248 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
249 | } |
250 | ||
251 | static void put_lock_stats(struct lock_class_stats *stats) | |
252 | { | |
1871e52c | 253 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
254 | } |
255 | ||
256 | static void lock_release_holdtime(struct held_lock *hlock) | |
257 | { | |
258 | struct lock_class_stats *stats; | |
3365e779 | 259 | u64 holdtime; |
f20786ff PZ |
260 | |
261 | if (!lock_stat) | |
262 | return; | |
263 | ||
3365e779 | 264 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 265 | |
f82b217e | 266 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
267 | if (hlock->read) |
268 | lock_time_inc(&stats->read_holdtime, holdtime); | |
269 | else | |
270 | lock_time_inc(&stats->write_holdtime, holdtime); | |
271 | put_lock_stats(stats); | |
272 | } | |
273 | #else | |
274 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
275 | { | |
276 | } | |
277 | #endif | |
278 | ||
fbb9ce95 IM |
279 | /* |
280 | * We keep a global list of all lock classes. The list only grows, | |
281 | * never shrinks. The list is only accessed with the lockdep | |
282 | * spinlock lock held. | |
283 | */ | |
284 | LIST_HEAD(all_lock_classes); | |
285 | ||
286 | /* | |
287 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
288 | */ | |
289 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
290 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 291 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
292 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
293 | ||
a63f38cc | 294 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
fbb9ce95 | 295 | |
fbb9ce95 IM |
296 | /* |
297 | * We put the lock dependency chains into a hash-table as well, to cache | |
298 | * their existence: | |
299 | */ | |
300 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
301 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 302 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
303 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
304 | ||
a63f38cc | 305 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
fbb9ce95 IM |
306 | |
307 | /* | |
308 | * The hash key of the lock dependency chains is a hash itself too: | |
309 | * it's a hash of all locks taken up to that lock, including that lock. | |
310 | * It's a 64-bit hash, because it's important for the keys to be | |
311 | * unique. | |
312 | */ | |
dfaaf3fa PZ |
313 | static inline u64 iterate_chain_key(u64 key, u32 idx) |
314 | { | |
315 | u32 k0 = key, k1 = key >> 32; | |
316 | ||
317 | __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ | |
318 | ||
319 | return k0 | (u64)k1 << 32; | |
320 | } | |
fbb9ce95 | 321 | |
1d09daa5 | 322 | void lockdep_off(void) |
fbb9ce95 IM |
323 | { |
324 | current->lockdep_recursion++; | |
325 | } | |
fbb9ce95 IM |
326 | EXPORT_SYMBOL(lockdep_off); |
327 | ||
1d09daa5 | 328 | void lockdep_on(void) |
fbb9ce95 IM |
329 | { |
330 | current->lockdep_recursion--; | |
331 | } | |
fbb9ce95 IM |
332 | EXPORT_SYMBOL(lockdep_on); |
333 | ||
fbb9ce95 IM |
334 | /* |
335 | * Debugging switches: | |
336 | */ | |
337 | ||
338 | #define VERBOSE 0 | |
33e94e96 | 339 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
340 | |
341 | #if VERBOSE | |
342 | # define HARDIRQ_VERBOSE 1 | |
343 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 344 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
345 | #else |
346 | # define HARDIRQ_VERBOSE 0 | |
347 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 348 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
349 | #endif |
350 | ||
cf40bd16 | 351 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
352 | /* |
353 | * Quick filtering for interesting events: | |
354 | */ | |
355 | static int class_filter(struct lock_class *class) | |
356 | { | |
f9829cce AK |
357 | #if 0 |
358 | /* Example */ | |
fbb9ce95 | 359 | if (class->name_version == 1 && |
f9829cce | 360 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
361 | return 1; |
362 | if (class->name_version == 1 && | |
f9829cce | 363 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 364 | return 1; |
f9829cce | 365 | #endif |
a6640897 IM |
366 | /* Filter everything else. 1 would be to allow everything else */ |
367 | return 0; | |
fbb9ce95 IM |
368 | } |
369 | #endif | |
370 | ||
371 | static int verbose(struct lock_class *class) | |
372 | { | |
373 | #if VERBOSE | |
374 | return class_filter(class); | |
375 | #endif | |
376 | return 0; | |
377 | } | |
378 | ||
fbb9ce95 IM |
379 | /* |
380 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 381 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
382 | */ |
383 | unsigned long nr_stack_trace_entries; | |
384 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
385 | ||
2c522836 DJ |
386 | static void print_lockdep_off(const char *bug_msg) |
387 | { | |
388 | printk(KERN_DEBUG "%s\n", bug_msg); | |
389 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 390 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 391 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 392 | #endif |
2c522836 DJ |
393 | } |
394 | ||
fbb9ce95 IM |
395 | static int save_trace(struct stack_trace *trace) |
396 | { | |
397 | trace->nr_entries = 0; | |
398 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
399 | trace->entries = stack_trace + nr_stack_trace_entries; | |
400 | ||
5a1b3999 | 401 | trace->skip = 3; |
5a1b3999 | 402 | |
ab1b6f03 | 403 | save_stack_trace(trace); |
fbb9ce95 | 404 | |
4f84f433 PZ |
405 | /* |
406 | * Some daft arches put -1 at the end to indicate its a full trace. | |
407 | * | |
408 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
409 | * complete trace that maxes out the entries provided will be reported | |
410 | * as incomplete, friggin useless </rant> | |
411 | */ | |
ea5b41f9 LT |
412 | if (trace->nr_entries != 0 && |
413 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
414 | trace->nr_entries--; |
415 | ||
fbb9ce95 IM |
416 | trace->max_entries = trace->nr_entries; |
417 | ||
418 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 419 | |
4f84f433 | 420 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
421 | if (!debug_locks_off_graph_unlock()) |
422 | return 0; | |
423 | ||
2c522836 | 424 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
425 | dump_stack(); |
426 | ||
fbb9ce95 IM |
427 | return 0; |
428 | } | |
429 | ||
430 | return 1; | |
431 | } | |
432 | ||
433 | unsigned int nr_hardirq_chains; | |
434 | unsigned int nr_softirq_chains; | |
435 | unsigned int nr_process_chains; | |
436 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
437 | |
438 | #ifdef CONFIG_DEBUG_LOCKDEP | |
fbb9ce95 IM |
439 | /* |
440 | * Various lockdep statistics: | |
441 | */ | |
bd6d29c2 | 442 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
443 | #endif |
444 | ||
445 | /* | |
446 | * Locking printouts: | |
447 | */ | |
448 | ||
fabe9c42 | 449 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
450 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
451 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
452 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
453 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 454 | |
fbb9ce95 IM |
455 | static const char *usage_str[] = |
456 | { | |
fabe9c42 PZ |
457 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
458 | #include "lockdep_states.h" | |
459 | #undef LOCKDEP_STATE | |
460 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
461 | }; |
462 | ||
463 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
464 | { | |
ffb45122 | 465 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
466 | } |
467 | ||
3ff176ca | 468 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 469 | { |
3ff176ca PZ |
470 | return 1UL << bit; |
471 | } | |
fbb9ce95 | 472 | |
3ff176ca PZ |
473 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
474 | { | |
475 | char c = '.'; | |
476 | ||
477 | if (class->usage_mask & lock_flag(bit + 2)) | |
478 | c = '+'; | |
479 | if (class->usage_mask & lock_flag(bit)) { | |
480 | c = '-'; | |
481 | if (class->usage_mask & lock_flag(bit + 2)) | |
482 | c = '?'; | |
fbb9ce95 IM |
483 | } |
484 | ||
3ff176ca PZ |
485 | return c; |
486 | } | |
cf40bd16 | 487 | |
f510b233 | 488 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 489 | { |
f510b233 | 490 | int i = 0; |
cf40bd16 | 491 | |
f510b233 PZ |
492 | #define LOCKDEP_STATE(__STATE) \ |
493 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
494 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
495 | #include "lockdep_states.h" | |
496 | #undef LOCKDEP_STATE | |
497 | ||
498 | usage[i] = '\0'; | |
fbb9ce95 IM |
499 | } |
500 | ||
e5e78d08 | 501 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
502 | { |
503 | char str[KSYM_NAME_LEN]; | |
504 | const char *name; | |
505 | ||
fbb9ce95 IM |
506 | name = class->name; |
507 | if (!name) { | |
508 | name = __get_key_name(class->key, str); | |
e5e78d08 | 509 | printk("%s", name); |
fbb9ce95 | 510 | } else { |
e5e78d08 | 511 | printk("%s", name); |
fbb9ce95 IM |
512 | if (class->name_version > 1) |
513 | printk("#%d", class->name_version); | |
514 | if (class->subclass) | |
515 | printk("/%d", class->subclass); | |
516 | } | |
e5e78d08 SR |
517 | } |
518 | ||
519 | static void print_lock_name(struct lock_class *class) | |
520 | { | |
521 | char usage[LOCK_USAGE_CHARS]; | |
522 | ||
523 | get_usage_chars(class, usage); | |
524 | ||
525 | printk(" ("); | |
526 | __print_lock_name(class); | |
f510b233 | 527 | printk("){%s}", usage); |
fbb9ce95 IM |
528 | } |
529 | ||
530 | static void print_lockdep_cache(struct lockdep_map *lock) | |
531 | { | |
532 | const char *name; | |
9281acea | 533 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
534 | |
535 | name = lock->name; | |
536 | if (!name) | |
537 | name = __get_key_name(lock->key->subkeys, str); | |
538 | ||
539 | printk("%s", name); | |
540 | } | |
541 | ||
542 | static void print_lock(struct held_lock *hlock) | |
543 | { | |
d7bc3197 PZ |
544 | /* |
545 | * We can be called locklessly through debug_show_all_locks() so be | |
546 | * extra careful, the hlock might have been released and cleared. | |
547 | */ | |
548 | unsigned int class_idx = hlock->class_idx; | |
549 | ||
550 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ | |
551 | barrier(); | |
552 | ||
553 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { | |
554 | printk("<RELEASED>\n"); | |
555 | return; | |
556 | } | |
557 | ||
558 | print_lock_name(lock_classes + class_idx - 1); | |
fbb9ce95 IM |
559 | printk(", at: "); |
560 | print_ip_sym(hlock->acquire_ip); | |
561 | } | |
562 | ||
563 | static void lockdep_print_held_locks(struct task_struct *curr) | |
564 | { | |
565 | int i, depth = curr->lockdep_depth; | |
566 | ||
567 | if (!depth) { | |
ba25f9dc | 568 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
569 | return; |
570 | } | |
571 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 572 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
573 | |
574 | for (i = 0; i < depth; i++) { | |
575 | printk(" #%d: ", i); | |
576 | print_lock(curr->held_locks + i); | |
577 | } | |
578 | } | |
fbb9ce95 | 579 | |
fbdc4b9a | 580 | static void print_kernel_ident(void) |
8e18257d | 581 | { |
fbdc4b9a | 582 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 583 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
584 | init_utsname()->version, |
585 | print_tainted()); | |
8e18257d PZ |
586 | } |
587 | ||
588 | static int very_verbose(struct lock_class *class) | |
589 | { | |
590 | #if VERY_VERBOSE | |
591 | return class_filter(class); | |
592 | #endif | |
593 | return 0; | |
594 | } | |
595 | ||
fbb9ce95 | 596 | /* |
8e18257d | 597 | * Is this the address of a static object: |
fbb9ce95 | 598 | */ |
8dce7a9a | 599 | #ifdef __KERNEL__ |
8e18257d | 600 | static int static_obj(void *obj) |
fbb9ce95 | 601 | { |
8e18257d PZ |
602 | unsigned long start = (unsigned long) &_stext, |
603 | end = (unsigned long) &_end, | |
604 | addr = (unsigned long) obj; | |
8e18257d | 605 | |
fbb9ce95 | 606 | /* |
8e18257d | 607 | * static variable? |
fbb9ce95 | 608 | */ |
8e18257d PZ |
609 | if ((addr >= start) && (addr < end)) |
610 | return 1; | |
fbb9ce95 | 611 | |
2a9ad18d MF |
612 | if (arch_is_kernel_data(addr)) |
613 | return 1; | |
614 | ||
fbb9ce95 | 615 | /* |
10fad5e4 | 616 | * in-kernel percpu var? |
fbb9ce95 | 617 | */ |
10fad5e4 TH |
618 | if (is_kernel_percpu_address(addr)) |
619 | return 1; | |
fbb9ce95 | 620 | |
8e18257d | 621 | /* |
10fad5e4 | 622 | * module static or percpu var? |
8e18257d | 623 | */ |
10fad5e4 | 624 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 625 | } |
8dce7a9a | 626 | #endif |
99de055a | 627 | |
fbb9ce95 | 628 | /* |
8e18257d PZ |
629 | * To make lock name printouts unique, we calculate a unique |
630 | * class->name_version generation counter: | |
fbb9ce95 | 631 | */ |
8e18257d | 632 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 633 | { |
8e18257d PZ |
634 | struct lock_class *class; |
635 | int count = 0; | |
fbb9ce95 | 636 | |
8e18257d | 637 | if (!new_class->name) |
fbb9ce95 IM |
638 | return 0; |
639 | ||
35a9393c | 640 | list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
641 | if (new_class->key - new_class->subclass == class->key) |
642 | return class->name_version; | |
643 | if (class->name && !strcmp(class->name, new_class->name)) | |
644 | count = max(count, class->name_version); | |
645 | } | |
fbb9ce95 | 646 | |
8e18257d | 647 | return count + 1; |
fbb9ce95 IM |
648 | } |
649 | ||
8e18257d PZ |
650 | /* |
651 | * Register a lock's class in the hash-table, if the class is not present | |
652 | * yet. Otherwise we look it up. We cache the result in the lock object | |
653 | * itself, so actual lookup of the hash should be once per lock object. | |
654 | */ | |
655 | static inline struct lock_class * | |
656 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 657 | { |
8e18257d | 658 | struct lockdep_subclass_key *key; |
a63f38cc | 659 | struct hlist_head *hash_head; |
8e18257d | 660 | struct lock_class *class; |
fbb9ce95 | 661 | |
4ba053c0 HM |
662 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
663 | debug_locks_off(); | |
664 | printk(KERN_ERR | |
665 | "BUG: looking up invalid subclass: %u\n", subclass); | |
666 | printk(KERN_ERR | |
667 | "turning off the locking correctness validator.\n"); | |
668 | dump_stack(); | |
669 | return NULL; | |
670 | } | |
671 | ||
8e18257d PZ |
672 | /* |
673 | * Static locks do not have their class-keys yet - for them the key | |
674 | * is the lock object itself: | |
675 | */ | |
676 | if (unlikely(!lock->key)) | |
677 | lock->key = (void *)lock; | |
fbb9ce95 | 678 | |
8e18257d PZ |
679 | /* |
680 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
681 | * lock_class_key variable is passed in through the mutex_init() | |
682 | * (or spin_lock_init()) call - which acts as the key. For static | |
683 | * locks we use the lock object itself as the key. | |
684 | */ | |
4b32d0a4 PZ |
685 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
686 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 687 | |
8e18257d | 688 | key = lock->key->subkeys + subclass; |
ca268c69 | 689 | |
8e18257d | 690 | hash_head = classhashentry(key); |
74c383f1 | 691 | |
8e18257d | 692 | /* |
35a9393c | 693 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 694 | */ |
35a9393c PZ |
695 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
696 | return NULL; | |
697 | ||
a63f38cc | 698 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
4b32d0a4 | 699 | if (class->key == key) { |
0119fee4 PZ |
700 | /* |
701 | * Huh! same key, different name? Did someone trample | |
702 | * on some memory? We're most confused. | |
703 | */ | |
4b32d0a4 | 704 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 705 | return class; |
4b32d0a4 PZ |
706 | } |
707 | } | |
fbb9ce95 | 708 | |
8e18257d | 709 | return NULL; |
fbb9ce95 IM |
710 | } |
711 | ||
712 | /* | |
8e18257d PZ |
713 | * Register a lock's class in the hash-table, if the class is not present |
714 | * yet. Otherwise we look it up. We cache the result in the lock object | |
715 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 716 | */ |
c003ed92 | 717 | static struct lock_class * |
8e18257d | 718 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
fbb9ce95 | 719 | { |
8e18257d | 720 | struct lockdep_subclass_key *key; |
a63f38cc | 721 | struct hlist_head *hash_head; |
8e18257d | 722 | struct lock_class *class; |
35a9393c PZ |
723 | |
724 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
725 | |
726 | class = look_up_lock_class(lock, subclass); | |
727 | if (likely(class)) | |
87cdee71 | 728 | goto out_set_class_cache; |
8e18257d PZ |
729 | |
730 | /* | |
731 | * Debug-check: all keys must be persistent! | |
732 | */ | |
733 | if (!static_obj(lock->key)) { | |
734 | debug_locks_off(); | |
735 | printk("INFO: trying to register non-static key.\n"); | |
736 | printk("the code is fine but needs lockdep annotation.\n"); | |
737 | printk("turning off the locking correctness validator.\n"); | |
738 | dump_stack(); | |
739 | ||
740 | return NULL; | |
741 | } | |
742 | ||
743 | key = lock->key->subkeys + subclass; | |
744 | hash_head = classhashentry(key); | |
745 | ||
8e18257d | 746 | if (!graph_lock()) { |
8e18257d PZ |
747 | return NULL; |
748 | } | |
749 | /* | |
750 | * We have to do the hash-walk again, to avoid races | |
751 | * with another CPU: | |
752 | */ | |
a63f38cc | 753 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
754 | if (class->key == key) |
755 | goto out_unlock_set; | |
35a9393c PZ |
756 | } |
757 | ||
8e18257d PZ |
758 | /* |
759 | * Allocate a new key from the static array, and add it to | |
760 | * the hash: | |
761 | */ | |
762 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
763 | if (!debug_locks_off_graph_unlock()) { | |
8e18257d PZ |
764 | return NULL; |
765 | } | |
8e18257d | 766 | |
2c522836 | 767 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 768 | dump_stack(); |
8e18257d PZ |
769 | return NULL; |
770 | } | |
771 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 772 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
773 | class->key = key; |
774 | class->name = lock->name; | |
775 | class->subclass = subclass; | |
776 | INIT_LIST_HEAD(&class->lock_entry); | |
777 | INIT_LIST_HEAD(&class->locks_before); | |
778 | INIT_LIST_HEAD(&class->locks_after); | |
779 | class->name_version = count_matching_names(class); | |
780 | /* | |
781 | * We use RCU's safe list-add method to make | |
782 | * parallel walking of the hash-list safe: | |
783 | */ | |
a63f38cc | 784 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
1481197b DF |
785 | /* |
786 | * Add it to the global list of classes: | |
787 | */ | |
788 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
789 | |
790 | if (verbose(class)) { | |
791 | graph_unlock(); | |
8e18257d PZ |
792 | |
793 | printk("\nnew class %p: %s", class->key, class->name); | |
794 | if (class->name_version > 1) | |
795 | printk("#%d", class->name_version); | |
796 | printk("\n"); | |
797 | dump_stack(); | |
798 | ||
8e18257d | 799 | if (!graph_lock()) { |
8e18257d PZ |
800 | return NULL; |
801 | } | |
802 | } | |
803 | out_unlock_set: | |
804 | graph_unlock(); | |
8e18257d | 805 | |
87cdee71 | 806 | out_set_class_cache: |
8e18257d | 807 | if (!subclass || force) |
62016250 HM |
808 | lock->class_cache[0] = class; |
809 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
810 | lock->class_cache[subclass] = class; | |
8e18257d | 811 | |
0119fee4 PZ |
812 | /* |
813 | * Hash collision, did we smoke some? We found a class with a matching | |
814 | * hash but the subclass -- which is hashed in -- didn't match. | |
815 | */ | |
8e18257d PZ |
816 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
817 | return NULL; | |
818 | ||
819 | return class; | |
820 | } | |
821 | ||
822 | #ifdef CONFIG_PROVE_LOCKING | |
823 | /* | |
824 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
825 | * with NULL on failure) | |
826 | */ | |
827 | static struct lock_list *alloc_list_entry(void) | |
828 | { | |
829 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
830 | if (!debug_locks_off_graph_unlock()) | |
831 | return NULL; | |
832 | ||
2c522836 | 833 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 834 | dump_stack(); |
8e18257d PZ |
835 | return NULL; |
836 | } | |
837 | return list_entries + nr_list_entries++; | |
838 | } | |
839 | ||
840 | /* | |
841 | * Add a new dependency to the head of the list: | |
842 | */ | |
843 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
4726f2a6 YZ |
844 | struct list_head *head, unsigned long ip, |
845 | int distance, struct stack_trace *trace) | |
8e18257d PZ |
846 | { |
847 | struct lock_list *entry; | |
848 | /* | |
849 | * Lock not present yet - get a new dependency struct and | |
850 | * add it to the list: | |
851 | */ | |
852 | entry = alloc_list_entry(); | |
853 | if (!entry) | |
854 | return 0; | |
855 | ||
74870172 ZY |
856 | entry->class = this; |
857 | entry->distance = distance; | |
4726f2a6 | 858 | entry->trace = *trace; |
8e18257d | 859 | /* |
35a9393c PZ |
860 | * Both allocation and removal are done under the graph lock; but |
861 | * iteration is under RCU-sched; see look_up_lock_class() and | |
862 | * lockdep_free_key_range(). | |
8e18257d PZ |
863 | */ |
864 | list_add_tail_rcu(&entry->entry, head); | |
865 | ||
866 | return 1; | |
867 | } | |
868 | ||
98c33edd PZ |
869 | /* |
870 | * For good efficiency of modular, we use power of 2 | |
871 | */ | |
af012961 PZ |
872 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
873 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
874 | ||
98c33edd PZ |
875 | /* |
876 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
877 | * breadth-first search(BFS)algorithem, by which we can build |
878 | * the shortest path from the next lock to be acquired to the | |
879 | * previous held lock if there is a circular between them. | |
98c33edd | 880 | */ |
af012961 PZ |
881 | struct circular_queue { |
882 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
883 | unsigned int front, rear; | |
884 | }; | |
885 | ||
886 | static struct circular_queue lock_cq; | |
af012961 | 887 | |
12f3dfd0 | 888 | unsigned int max_bfs_queue_depth; |
af012961 | 889 | |
e351b660 ML |
890 | static unsigned int lockdep_dependency_gen_id; |
891 | ||
af012961 PZ |
892 | static inline void __cq_init(struct circular_queue *cq) |
893 | { | |
894 | cq->front = cq->rear = 0; | |
e351b660 | 895 | lockdep_dependency_gen_id++; |
af012961 PZ |
896 | } |
897 | ||
898 | static inline int __cq_empty(struct circular_queue *cq) | |
899 | { | |
900 | return (cq->front == cq->rear); | |
901 | } | |
902 | ||
903 | static inline int __cq_full(struct circular_queue *cq) | |
904 | { | |
905 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
906 | } | |
907 | ||
908 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
909 | { | |
910 | if (__cq_full(cq)) | |
911 | return -1; | |
912 | ||
913 | cq->element[cq->rear] = elem; | |
914 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
915 | return 0; | |
916 | } | |
917 | ||
918 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
919 | { | |
920 | if (__cq_empty(cq)) | |
921 | return -1; | |
922 | ||
923 | *elem = cq->element[cq->front]; | |
924 | cq->front = (cq->front + 1) & CQ_MASK; | |
925 | return 0; | |
926 | } | |
927 | ||
928 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
929 | { | |
930 | return (cq->rear - cq->front) & CQ_MASK; | |
931 | } | |
932 | ||
933 | static inline void mark_lock_accessed(struct lock_list *lock, | |
934 | struct lock_list *parent) | |
935 | { | |
936 | unsigned long nr; | |
98c33edd | 937 | |
af012961 | 938 | nr = lock - list_entries; |
0119fee4 | 939 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 940 | lock->parent = parent; |
e351b660 | 941 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
942 | } |
943 | ||
944 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
945 | { | |
946 | unsigned long nr; | |
98c33edd | 947 | |
af012961 | 948 | nr = lock - list_entries; |
0119fee4 | 949 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 950 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
951 | } |
952 | ||
953 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
954 | { | |
955 | return child->parent; | |
956 | } | |
957 | ||
958 | static inline int get_lock_depth(struct lock_list *child) | |
959 | { | |
960 | int depth = 0; | |
961 | struct lock_list *parent; | |
962 | ||
963 | while ((parent = get_lock_parent(child))) { | |
964 | child = parent; | |
965 | depth++; | |
966 | } | |
967 | return depth; | |
968 | } | |
969 | ||
9e2d551e | 970 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
971 | void *data, |
972 | int (*match)(struct lock_list *entry, void *data), | |
973 | struct lock_list **target_entry, | |
974 | int forward) | |
c94aa5ca ML |
975 | { |
976 | struct lock_list *entry; | |
d588e461 | 977 | struct list_head *head; |
c94aa5ca ML |
978 | struct circular_queue *cq = &lock_cq; |
979 | int ret = 1; | |
980 | ||
9e2d551e | 981 | if (match(source_entry, data)) { |
c94aa5ca ML |
982 | *target_entry = source_entry; |
983 | ret = 0; | |
984 | goto exit; | |
985 | } | |
986 | ||
d588e461 ML |
987 | if (forward) |
988 | head = &source_entry->class->locks_after; | |
989 | else | |
990 | head = &source_entry->class->locks_before; | |
991 | ||
992 | if (list_empty(head)) | |
993 | goto exit; | |
994 | ||
995 | __cq_init(cq); | |
c94aa5ca ML |
996 | __cq_enqueue(cq, (unsigned long)source_entry); |
997 | ||
998 | while (!__cq_empty(cq)) { | |
999 | struct lock_list *lock; | |
c94aa5ca ML |
1000 | |
1001 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1002 | ||
1003 | if (!lock->class) { | |
1004 | ret = -2; | |
1005 | goto exit; | |
1006 | } | |
1007 | ||
1008 | if (forward) | |
1009 | head = &lock->class->locks_after; | |
1010 | else | |
1011 | head = &lock->class->locks_before; | |
1012 | ||
35a9393c PZ |
1013 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1014 | ||
1015 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1016 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1017 | unsigned int cq_depth; |
c94aa5ca | 1018 | mark_lock_accessed(entry, lock); |
9e2d551e | 1019 | if (match(entry, data)) { |
c94aa5ca ML |
1020 | *target_entry = entry; |
1021 | ret = 0; | |
1022 | goto exit; | |
1023 | } | |
1024 | ||
1025 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1026 | ret = -1; | |
1027 | goto exit; | |
1028 | } | |
12f3dfd0 ML |
1029 | cq_depth = __cq_get_elem_count(cq); |
1030 | if (max_bfs_queue_depth < cq_depth) | |
1031 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1032 | } |
1033 | } | |
1034 | } | |
1035 | exit: | |
1036 | return ret; | |
1037 | } | |
1038 | ||
d7aaba14 | 1039 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1040 | void *data, |
1041 | int (*match)(struct lock_list *entry, void *data), | |
1042 | struct lock_list **target_entry) | |
c94aa5ca | 1043 | { |
9e2d551e | 1044 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1045 | |
1046 | } | |
1047 | ||
d7aaba14 | 1048 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1049 | void *data, |
1050 | int (*match)(struct lock_list *entry, void *data), | |
1051 | struct lock_list **target_entry) | |
c94aa5ca | 1052 | { |
9e2d551e | 1053 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1054 | |
1055 | } | |
1056 | ||
8e18257d PZ |
1057 | /* |
1058 | * Recursive, forwards-direction lock-dependency checking, used for | |
1059 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1060 | * checking. | |
8e18257d | 1061 | */ |
8e18257d PZ |
1062 | |
1063 | /* | |
1064 | * Print a dependency chain entry (this is only done when a deadlock | |
1065 | * has been detected): | |
1066 | */ | |
1067 | static noinline int | |
24208ca7 | 1068 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1069 | { |
1070 | if (debug_locks_silent) | |
1071 | return 0; | |
1072 | printk("\n-> #%u", depth); | |
1073 | print_lock_name(target->class); | |
1074 | printk(":\n"); | |
1075 | print_stack_trace(&target->trace, 6); | |
1076 | ||
1077 | return 0; | |
1078 | } | |
1079 | ||
f4185812 SR |
1080 | static void |
1081 | print_circular_lock_scenario(struct held_lock *src, | |
1082 | struct held_lock *tgt, | |
1083 | struct lock_list *prt) | |
1084 | { | |
1085 | struct lock_class *source = hlock_class(src); | |
1086 | struct lock_class *target = hlock_class(tgt); | |
1087 | struct lock_class *parent = prt->class; | |
1088 | ||
1089 | /* | |
1090 | * A direct locking problem where unsafe_class lock is taken | |
1091 | * directly by safe_class lock, then all we need to show | |
1092 | * is the deadlock scenario, as it is obvious that the | |
1093 | * unsafe lock is taken under the safe lock. | |
1094 | * | |
1095 | * But if there is a chain instead, where the safe lock takes | |
1096 | * an intermediate lock (middle_class) where this lock is | |
1097 | * not the same as the safe lock, then the lock chain is | |
1098 | * used to describe the problem. Otherwise we would need | |
1099 | * to show a different CPU case for each link in the chain | |
1100 | * from the safe_class lock to the unsafe_class lock. | |
1101 | */ | |
1102 | if (parent != source) { | |
1103 | printk("Chain exists of:\n "); | |
1104 | __print_lock_name(source); | |
1105 | printk(" --> "); | |
1106 | __print_lock_name(parent); | |
1107 | printk(" --> "); | |
1108 | __print_lock_name(target); | |
1109 | printk("\n\n"); | |
1110 | } | |
1111 | ||
1112 | printk(" Possible unsafe locking scenario:\n\n"); | |
1113 | printk(" CPU0 CPU1\n"); | |
1114 | printk(" ---- ----\n"); | |
1115 | printk(" lock("); | |
1116 | __print_lock_name(target); | |
1117 | printk(");\n"); | |
1118 | printk(" lock("); | |
1119 | __print_lock_name(parent); | |
1120 | printk(");\n"); | |
1121 | printk(" lock("); | |
1122 | __print_lock_name(target); | |
1123 | printk(");\n"); | |
1124 | printk(" lock("); | |
1125 | __print_lock_name(source); | |
1126 | printk(");\n"); | |
1127 | printk("\n *** DEADLOCK ***\n\n"); | |
1128 | } | |
1129 | ||
8e18257d PZ |
1130 | /* |
1131 | * When a circular dependency is detected, print the | |
1132 | * header first: | |
1133 | */ | |
1134 | static noinline int | |
db0002a3 ML |
1135 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1136 | struct held_lock *check_src, | |
1137 | struct held_lock *check_tgt) | |
8e18257d PZ |
1138 | { |
1139 | struct task_struct *curr = current; | |
1140 | ||
c94aa5ca | 1141 | if (debug_locks_silent) |
8e18257d PZ |
1142 | return 0; |
1143 | ||
b3fbab05 PM |
1144 | printk("\n"); |
1145 | printk("======================================================\n"); | |
1146 | printk("[ INFO: possible circular locking dependency detected ]\n"); | |
fbdc4b9a | 1147 | print_kernel_ident(); |
b3fbab05 | 1148 | printk("-------------------------------------------------------\n"); |
8e18257d | 1149 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1150 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1151 | print_lock(check_src); |
8e18257d | 1152 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1153 | print_lock(check_tgt); |
8e18257d PZ |
1154 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1155 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1156 | ||
1157 | print_circular_bug_entry(entry, depth); | |
1158 | ||
1159 | return 0; | |
1160 | } | |
1161 | ||
9e2d551e ML |
1162 | static inline int class_equal(struct lock_list *entry, void *data) |
1163 | { | |
1164 | return entry->class == data; | |
1165 | } | |
1166 | ||
db0002a3 ML |
1167 | static noinline int print_circular_bug(struct lock_list *this, |
1168 | struct lock_list *target, | |
1169 | struct held_lock *check_src, | |
1170 | struct held_lock *check_tgt) | |
8e18257d PZ |
1171 | { |
1172 | struct task_struct *curr = current; | |
c94aa5ca | 1173 | struct lock_list *parent; |
f4185812 | 1174 | struct lock_list *first_parent; |
24208ca7 | 1175 | int depth; |
8e18257d | 1176 | |
c94aa5ca | 1177 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1178 | return 0; |
1179 | ||
db0002a3 | 1180 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1181 | return 0; |
1182 | ||
c94aa5ca ML |
1183 | depth = get_lock_depth(target); |
1184 | ||
db0002a3 | 1185 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1186 | |
1187 | parent = get_lock_parent(target); | |
f4185812 | 1188 | first_parent = parent; |
c94aa5ca ML |
1189 | |
1190 | while (parent) { | |
1191 | print_circular_bug_entry(parent, --depth); | |
1192 | parent = get_lock_parent(parent); | |
1193 | } | |
8e18257d PZ |
1194 | |
1195 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1196 | print_circular_lock_scenario(check_src, check_tgt, |
1197 | first_parent); | |
1198 | ||
8e18257d PZ |
1199 | lockdep_print_held_locks(curr); |
1200 | ||
1201 | printk("\nstack backtrace:\n"); | |
1202 | dump_stack(); | |
1203 | ||
1204 | return 0; | |
1205 | } | |
1206 | ||
db0002a3 ML |
1207 | static noinline int print_bfs_bug(int ret) |
1208 | { | |
1209 | if (!debug_locks_off_graph_unlock()) | |
1210 | return 0; | |
1211 | ||
0119fee4 PZ |
1212 | /* |
1213 | * Breadth-first-search failed, graph got corrupted? | |
1214 | */ | |
db0002a3 ML |
1215 | WARN(1, "lockdep bfs error:%d\n", ret); |
1216 | ||
1217 | return 0; | |
1218 | } | |
1219 | ||
ef681026 | 1220 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1221 | { |
ef681026 ML |
1222 | (*(unsigned long *)data)++; |
1223 | return 0; | |
1224 | } | |
419ca3f1 | 1225 | |
5216d530 | 1226 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1227 | { |
1228 | unsigned long count = 0; | |
1229 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1230 | |
ef681026 | 1231 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1232 | |
ef681026 | 1233 | return count; |
419ca3f1 | 1234 | } |
419ca3f1 DM |
1235 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1236 | { | |
1237 | unsigned long ret, flags; | |
ef681026 ML |
1238 | struct lock_list this; |
1239 | ||
1240 | this.parent = NULL; | |
1241 | this.class = class; | |
419ca3f1 DM |
1242 | |
1243 | local_irq_save(flags); | |
0199c4e6 | 1244 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1245 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1246 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1247 | local_irq_restore(flags); |
1248 | ||
1249 | return ret; | |
1250 | } | |
1251 | ||
5216d530 | 1252 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1253 | { |
ef681026 ML |
1254 | unsigned long count = 0; |
1255 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1256 | |
ef681026 | 1257 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1258 | |
ef681026 | 1259 | return count; |
419ca3f1 DM |
1260 | } |
1261 | ||
1262 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1263 | { | |
1264 | unsigned long ret, flags; | |
ef681026 ML |
1265 | struct lock_list this; |
1266 | ||
1267 | this.parent = NULL; | |
1268 | this.class = class; | |
419ca3f1 DM |
1269 | |
1270 | local_irq_save(flags); | |
0199c4e6 | 1271 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1272 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1273 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1274 | local_irq_restore(flags); |
1275 | ||
1276 | return ret; | |
1277 | } | |
1278 | ||
8e18257d PZ |
1279 | /* |
1280 | * Prove that the dependency graph starting at <entry> can not | |
1281 | * lead to <target>. Print an error and return 0 if it does. | |
1282 | */ | |
1283 | static noinline int | |
db0002a3 ML |
1284 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1285 | struct lock_list **target_entry) | |
8e18257d | 1286 | { |
db0002a3 | 1287 | int result; |
8e18257d | 1288 | |
bd6d29c2 | 1289 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1290 | |
d7aaba14 | 1291 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1292 | |
db0002a3 ML |
1293 | return result; |
1294 | } | |
c94aa5ca | 1295 | |
81d68a96 | 1296 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1297 | /* |
1298 | * Forwards and backwards subgraph searching, for the purposes of | |
1299 | * proving that two subgraphs can be connected by a new dependency | |
1300 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1301 | */ | |
fbb9ce95 | 1302 | |
d7aaba14 ML |
1303 | static inline int usage_match(struct lock_list *entry, void *bit) |
1304 | { | |
1305 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1306 | } | |
1307 | ||
1308 | ||
1309 | ||
fbb9ce95 IM |
1310 | /* |
1311 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1312 | * at @root->class that matches @bit. |
fbb9ce95 | 1313 | * |
d7aaba14 ML |
1314 | * Return 0 if such a node exists in the subgraph, and put that node |
1315 | * into *@target_entry. | |
fbb9ce95 | 1316 | * |
d7aaba14 ML |
1317 | * Return 1 otherwise and keep *@target_entry unchanged. |
1318 | * Return <0 on error. | |
fbb9ce95 | 1319 | */ |
d7aaba14 ML |
1320 | static int |
1321 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1322 | struct lock_list **target_entry) | |
fbb9ce95 | 1323 | { |
d7aaba14 | 1324 | int result; |
fbb9ce95 | 1325 | |
bd6d29c2 | 1326 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1327 | |
d7aaba14 ML |
1328 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1329 | ||
1330 | return result; | |
fbb9ce95 IM |
1331 | } |
1332 | ||
1333 | /* | |
1334 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1335 | * at @root->class that matches @bit. |
fbb9ce95 | 1336 | * |
d7aaba14 ML |
1337 | * Return 0 if such a node exists in the subgraph, and put that node |
1338 | * into *@target_entry. | |
fbb9ce95 | 1339 | * |
d7aaba14 ML |
1340 | * Return 1 otherwise and keep *@target_entry unchanged. |
1341 | * Return <0 on error. | |
fbb9ce95 | 1342 | */ |
d7aaba14 ML |
1343 | static int |
1344 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1345 | struct lock_list **target_entry) | |
fbb9ce95 | 1346 | { |
d7aaba14 | 1347 | int result; |
fbb9ce95 | 1348 | |
bd6d29c2 | 1349 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1350 | |
d7aaba14 | 1351 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1352 | |
d7aaba14 | 1353 | return result; |
fbb9ce95 IM |
1354 | } |
1355 | ||
af012961 PZ |
1356 | static void print_lock_class_header(struct lock_class *class, int depth) |
1357 | { | |
1358 | int bit; | |
1359 | ||
1360 | printk("%*s->", depth, ""); | |
1361 | print_lock_name(class); | |
1362 | printk(" ops: %lu", class->ops); | |
1363 | printk(" {\n"); | |
1364 | ||
1365 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1366 | if (class->usage_mask & (1 << bit)) { | |
1367 | int len = depth; | |
1368 | ||
1369 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1370 | len += printk(" at:\n"); | |
1371 | print_stack_trace(class->usage_traces + bit, len); | |
1372 | } | |
1373 | } | |
1374 | printk("%*s }\n", depth, ""); | |
1375 | ||
1376 | printk("%*s ... key at: ",depth,""); | |
1377 | print_ip_sym((unsigned long)class->key); | |
1378 | } | |
1379 | ||
1380 | /* | |
1381 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1382 | */ | |
1383 | static void __used | |
1384 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1385 | struct lock_list *root) | |
1386 | { | |
1387 | struct lock_list *entry = leaf; | |
1388 | int depth; | |
1389 | ||
1390 | /*compute depth from generated tree by BFS*/ | |
1391 | depth = get_lock_depth(leaf); | |
1392 | ||
1393 | do { | |
1394 | print_lock_class_header(entry->class, depth); | |
1395 | printk("%*s ... acquired at:\n", depth, ""); | |
1396 | print_stack_trace(&entry->trace, 2); | |
1397 | printk("\n"); | |
1398 | ||
1399 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1400 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1401 | break; |
1402 | } | |
1403 | ||
1404 | entry = get_lock_parent(entry); | |
1405 | depth--; | |
1406 | } while (entry && (depth >= 0)); | |
1407 | ||
1408 | return; | |
1409 | } | |
d7aaba14 | 1410 | |
3003eba3 SR |
1411 | static void |
1412 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1413 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1414 | struct lock_class *prev_class, |
1415 | struct lock_class *next_class) | |
3003eba3 SR |
1416 | { |
1417 | struct lock_class *safe_class = safe_entry->class; | |
1418 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1419 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1420 | |
1421 | if (middle_class == safe_class) | |
dad3d743 | 1422 | middle_class = next_class; |
3003eba3 SR |
1423 | |
1424 | /* | |
1425 | * A direct locking problem where unsafe_class lock is taken | |
1426 | * directly by safe_class lock, then all we need to show | |
1427 | * is the deadlock scenario, as it is obvious that the | |
1428 | * unsafe lock is taken under the safe lock. | |
1429 | * | |
1430 | * But if there is a chain instead, where the safe lock takes | |
1431 | * an intermediate lock (middle_class) where this lock is | |
1432 | * not the same as the safe lock, then the lock chain is | |
1433 | * used to describe the problem. Otherwise we would need | |
1434 | * to show a different CPU case for each link in the chain | |
1435 | * from the safe_class lock to the unsafe_class lock. | |
1436 | */ | |
1437 | if (middle_class != unsafe_class) { | |
1438 | printk("Chain exists of:\n "); | |
1439 | __print_lock_name(safe_class); | |
1440 | printk(" --> "); | |
1441 | __print_lock_name(middle_class); | |
1442 | printk(" --> "); | |
1443 | __print_lock_name(unsafe_class); | |
1444 | printk("\n\n"); | |
1445 | } | |
1446 | ||
1447 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1448 | printk(" CPU0 CPU1\n"); | |
1449 | printk(" ---- ----\n"); | |
1450 | printk(" lock("); | |
1451 | __print_lock_name(unsafe_class); | |
1452 | printk(");\n"); | |
1453 | printk(" local_irq_disable();\n"); | |
1454 | printk(" lock("); | |
1455 | __print_lock_name(safe_class); | |
1456 | printk(");\n"); | |
1457 | printk(" lock("); | |
1458 | __print_lock_name(middle_class); | |
1459 | printk(");\n"); | |
1460 | printk(" <Interrupt>\n"); | |
1461 | printk(" lock("); | |
1462 | __print_lock_name(safe_class); | |
1463 | printk(");\n"); | |
1464 | printk("\n *** DEADLOCK ***\n\n"); | |
1465 | } | |
1466 | ||
fbb9ce95 IM |
1467 | static int |
1468 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1469 | struct lock_list *prev_root, |
1470 | struct lock_list *next_root, | |
1471 | struct lock_list *backwards_entry, | |
1472 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1473 | struct held_lock *prev, |
1474 | struct held_lock *next, | |
1475 | enum lock_usage_bit bit1, | |
1476 | enum lock_usage_bit bit2, | |
1477 | const char *irqclass) | |
1478 | { | |
74c383f1 | 1479 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1480 | return 0; |
1481 | ||
b3fbab05 PM |
1482 | printk("\n"); |
1483 | printk("======================================================\n"); | |
1484 | printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
fbb9ce95 | 1485 | irqclass, irqclass); |
fbdc4b9a | 1486 | print_kernel_ident(); |
b3fbab05 | 1487 | printk("------------------------------------------------------\n"); |
fbb9ce95 | 1488 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1489 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1490 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1491 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1492 | curr->hardirqs_enabled, | |
1493 | curr->softirqs_enabled); | |
1494 | print_lock(next); | |
1495 | ||
1496 | printk("\nand this task is already holding:\n"); | |
1497 | print_lock(prev); | |
1498 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1499 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1500 | printk(" ->"); |
f82b217e | 1501 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1502 | printk("\n"); |
1503 | ||
1504 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1505 | irqclass); | |
24208ca7 | 1506 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1507 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1508 | ||
24208ca7 | 1509 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1510 | |
1511 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1512 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1513 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1514 | printk("..."); | |
1515 | ||
24208ca7 | 1516 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1517 | |
1518 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1519 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1520 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1521 | |
fbb9ce95 IM |
1522 | lockdep_print_held_locks(curr); |
1523 | ||
24208ca7 ML |
1524 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1525 | printk(" and the holding lock:\n"); | |
1526 | if (!save_trace(&prev_root->trace)) | |
1527 | return 0; | |
1528 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1529 | |
24208ca7 ML |
1530 | printk("\nthe dependencies between the lock to be acquired"); |
1531 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1532 | if (!save_trace(&next_root->trace)) | |
1533 | return 0; | |
1534 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1535 | |
1536 | printk("\nstack backtrace:\n"); | |
1537 | dump_stack(); | |
1538 | ||
1539 | return 0; | |
1540 | } | |
1541 | ||
1542 | static int | |
1543 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1544 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1545 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1546 | { | |
1547 | int ret; | |
24208ca7 | 1548 | struct lock_list this, that; |
d7aaba14 | 1549 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1550 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1551 | |
1552 | this.parent = NULL; | |
1553 | ||
1554 | this.class = hlock_class(prev); | |
1555 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1556 | if (ret < 0) |
1557 | return print_bfs_bug(ret); | |
1558 | if (ret == 1) | |
1559 | return ret; | |
d7aaba14 | 1560 | |
24208ca7 ML |
1561 | that.parent = NULL; |
1562 | that.class = hlock_class(next); | |
1563 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1564 | if (ret < 0) |
1565 | return print_bfs_bug(ret); | |
1566 | if (ret == 1) | |
1567 | return ret; | |
fbb9ce95 | 1568 | |
24208ca7 ML |
1569 | return print_bad_irq_dependency(curr, &this, &that, |
1570 | target_entry, target_entry1, | |
1571 | prev, next, | |
fbb9ce95 IM |
1572 | bit_backwards, bit_forwards, irqclass); |
1573 | } | |
1574 | ||
4f367d8a PZ |
1575 | static const char *state_names[] = { |
1576 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1577 | __stringify(__STATE), |
4f367d8a PZ |
1578 | #include "lockdep_states.h" |
1579 | #undef LOCKDEP_STATE | |
1580 | }; | |
1581 | ||
1582 | static const char *state_rnames[] = { | |
1583 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1584 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1585 | #include "lockdep_states.h" |
1586 | #undef LOCKDEP_STATE | |
1587 | }; | |
1588 | ||
1589 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1590 | { |
4f367d8a PZ |
1591 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1592 | } | |
8e18257d | 1593 | |
4f367d8a PZ |
1594 | static int exclusive_bit(int new_bit) |
1595 | { | |
8e18257d | 1596 | /* |
4f367d8a PZ |
1597 | * USED_IN |
1598 | * USED_IN_READ | |
1599 | * ENABLED | |
1600 | * ENABLED_READ | |
1601 | * | |
1602 | * bit 0 - write/read | |
1603 | * bit 1 - used_in/enabled | |
1604 | * bit 2+ state | |
8e18257d | 1605 | */ |
4f367d8a PZ |
1606 | |
1607 | int state = new_bit & ~3; | |
1608 | int dir = new_bit & 2; | |
8e18257d PZ |
1609 | |
1610 | /* | |
4f367d8a | 1611 | * keep state, bit flip the direction and strip read. |
8e18257d | 1612 | */ |
4f367d8a PZ |
1613 | return state | (dir ^ 2); |
1614 | } | |
1615 | ||
1616 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1617 | struct held_lock *next, enum lock_usage_bit bit) | |
1618 | { | |
8e18257d | 1619 | /* |
4f367d8a PZ |
1620 | * Prove that the new dependency does not connect a hardirq-safe |
1621 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1622 | * the backwards-subgraph starting at <prev>, and the |
1623 | * forwards-subgraph starting at <next>: | |
1624 | */ | |
4f367d8a PZ |
1625 | if (!check_usage(curr, prev, next, bit, |
1626 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1627 | return 0; |
1628 | ||
4f367d8a PZ |
1629 | bit++; /* _READ */ |
1630 | ||
cf40bd16 | 1631 | /* |
4f367d8a PZ |
1632 | * Prove that the new dependency does not connect a hardirq-safe-read |
1633 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1634 | * the backwards-subgraph starting at <prev>, and the |
1635 | * forwards-subgraph starting at <next>: | |
1636 | */ | |
4f367d8a PZ |
1637 | if (!check_usage(curr, prev, next, bit, |
1638 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1639 | return 0; |
1640 | ||
4f367d8a PZ |
1641 | return 1; |
1642 | } | |
1643 | ||
1644 | static int | |
1645 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1646 | struct held_lock *next) | |
1647 | { | |
1648 | #define LOCKDEP_STATE(__STATE) \ | |
1649 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1650 | return 0; |
4f367d8a PZ |
1651 | #include "lockdep_states.h" |
1652 | #undef LOCKDEP_STATE | |
cf40bd16 | 1653 | |
8e18257d PZ |
1654 | return 1; |
1655 | } | |
1656 | ||
1657 | static void inc_chains(void) | |
1658 | { | |
1659 | if (current->hardirq_context) | |
1660 | nr_hardirq_chains++; | |
1661 | else { | |
1662 | if (current->softirq_context) | |
1663 | nr_softirq_chains++; | |
1664 | else | |
1665 | nr_process_chains++; | |
1666 | } | |
1667 | } | |
1668 | ||
1669 | #else | |
1670 | ||
1671 | static inline int | |
1672 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1673 | struct held_lock *next) | |
1674 | { | |
1675 | return 1; | |
1676 | } | |
1677 | ||
1678 | static inline void inc_chains(void) | |
1679 | { | |
1680 | nr_process_chains++; | |
1681 | } | |
1682 | ||
fbb9ce95 IM |
1683 | #endif |
1684 | ||
48702ecf SR |
1685 | static void |
1686 | print_deadlock_scenario(struct held_lock *nxt, | |
1687 | struct held_lock *prv) | |
1688 | { | |
1689 | struct lock_class *next = hlock_class(nxt); | |
1690 | struct lock_class *prev = hlock_class(prv); | |
1691 | ||
1692 | printk(" Possible unsafe locking scenario:\n\n"); | |
1693 | printk(" CPU0\n"); | |
1694 | printk(" ----\n"); | |
1695 | printk(" lock("); | |
1696 | __print_lock_name(prev); | |
1697 | printk(");\n"); | |
1698 | printk(" lock("); | |
1699 | __print_lock_name(next); | |
1700 | printk(");\n"); | |
1701 | printk("\n *** DEADLOCK ***\n\n"); | |
1702 | printk(" May be due to missing lock nesting notation\n\n"); | |
1703 | } | |
1704 | ||
fbb9ce95 IM |
1705 | static int |
1706 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1707 | struct held_lock *next) | |
1708 | { | |
74c383f1 | 1709 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1710 | return 0; |
1711 | ||
b3fbab05 PM |
1712 | printk("\n"); |
1713 | printk("=============================================\n"); | |
1714 | printk("[ INFO: possible recursive locking detected ]\n"); | |
fbdc4b9a | 1715 | print_kernel_ident(); |
b3fbab05 | 1716 | printk("---------------------------------------------\n"); |
fbb9ce95 | 1717 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1718 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1719 | print_lock(next); |
1720 | printk("\nbut task is already holding lock:\n"); | |
1721 | print_lock(prev); | |
1722 | ||
1723 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1724 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1725 | lockdep_print_held_locks(curr); |
1726 | ||
1727 | printk("\nstack backtrace:\n"); | |
1728 | dump_stack(); | |
1729 | ||
1730 | return 0; | |
1731 | } | |
1732 | ||
1733 | /* | |
1734 | * Check whether we are holding such a class already. | |
1735 | * | |
1736 | * (Note that this has to be done separately, because the graph cannot | |
1737 | * detect such classes of deadlocks.) | |
1738 | * | |
1739 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1740 | */ | |
1741 | static int | |
1742 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1743 | struct lockdep_map *next_instance, int read) | |
1744 | { | |
1745 | struct held_lock *prev; | |
7531e2f3 | 1746 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1747 | int i; |
1748 | ||
1749 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1750 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1751 | |
1752 | if (prev->instance == next->nest_lock) | |
1753 | nest = prev; | |
1754 | ||
f82b217e | 1755 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1756 | continue; |
7531e2f3 | 1757 | |
fbb9ce95 IM |
1758 | /* |
1759 | * Allow read-after-read recursion of the same | |
6c9076ec | 1760 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1761 | */ |
6c9076ec | 1762 | if ((read == 2) && prev->read) |
fbb9ce95 | 1763 | return 2; |
7531e2f3 PZ |
1764 | |
1765 | /* | |
1766 | * We're holding the nest_lock, which serializes this lock's | |
1767 | * nesting behaviour. | |
1768 | */ | |
1769 | if (nest) | |
1770 | return 2; | |
1771 | ||
fbb9ce95 IM |
1772 | return print_deadlock_bug(curr, prev, next); |
1773 | } | |
1774 | return 1; | |
1775 | } | |
1776 | ||
1777 | /* | |
1778 | * There was a chain-cache miss, and we are about to add a new dependency | |
1779 | * to a previous lock. We recursively validate the following rules: | |
1780 | * | |
1781 | * - would the adding of the <prev> -> <next> dependency create a | |
1782 | * circular dependency in the graph? [== circular deadlock] | |
1783 | * | |
1784 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1785 | * (in the full backwards-subgraph starting at <prev>) with any | |
1786 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1787 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1788 | * | |
1789 | * - does the new prev->next dependency connect any softirq-safe lock | |
1790 | * (in the full backwards-subgraph starting at <prev>) with any | |
1791 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1792 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1793 | * | |
1794 | * any of these scenarios could lead to a deadlock. | |
1795 | * | |
1796 | * Then if all the validations pass, we add the forwards and backwards | |
1797 | * dependency. | |
1798 | */ | |
1799 | static int | |
1800 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
8a5fd564 | 1801 | struct held_lock *next, int distance, int *stack_saved) |
fbb9ce95 IM |
1802 | { |
1803 | struct lock_list *entry; | |
1804 | int ret; | |
db0002a3 ML |
1805 | struct lock_list this; |
1806 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1807 | /* |
1808 | * Static variable, serialized by the graph_lock(). | |
1809 | * | |
1810 | * We use this static variable to save the stack trace in case | |
1811 | * we call into this function multiple times due to encountering | |
1812 | * trylocks in the held lock stack. | |
1813 | */ | |
1814 | static struct stack_trace trace; | |
fbb9ce95 IM |
1815 | |
1816 | /* | |
1817 | * Prove that the new <prev> -> <next> dependency would not | |
1818 | * create a circular dependency in the graph. (We do this by | |
1819 | * forward-recursing into the graph starting at <next>, and | |
1820 | * checking whether we can reach <prev>.) | |
1821 | * | |
1822 | * We are using global variables to control the recursion, to | |
1823 | * keep the stackframe size of the recursive functions low: | |
1824 | */ | |
db0002a3 ML |
1825 | this.class = hlock_class(next); |
1826 | this.parent = NULL; | |
1827 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1828 | if (unlikely(!ret)) | |
1829 | return print_circular_bug(&this, target_entry, next, prev); | |
1830 | else if (unlikely(ret < 0)) | |
1831 | return print_bfs_bug(ret); | |
c94aa5ca | 1832 | |
8e18257d | 1833 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1834 | return 0; |
1835 | ||
fbb9ce95 IM |
1836 | /* |
1837 | * For recursive read-locks we do all the dependency checks, | |
1838 | * but we dont store read-triggered dependencies (only | |
1839 | * write-triggered dependencies). This ensures that only the | |
1840 | * write-side dependencies matter, and that if for example a | |
1841 | * write-lock never takes any other locks, then the reads are | |
1842 | * equivalent to a NOP. | |
1843 | */ | |
1844 | if (next->read == 2 || prev->read == 2) | |
1845 | return 1; | |
1846 | /* | |
1847 | * Is the <prev> -> <next> dependency already present? | |
1848 | * | |
1849 | * (this may occur even though this is a new chain: consider | |
1850 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1851 | * chains - the second one will be new, but L1 already has | |
1852 | * L2 added to its dependency list, due to the first chain.) | |
1853 | */ | |
f82b217e DJ |
1854 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1855 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1856 | if (distance == 1) |
1857 | entry->distance = 1; | |
fbb9ce95 | 1858 | return 2; |
068135e6 | 1859 | } |
fbb9ce95 IM |
1860 | } |
1861 | ||
8a5fd564 DV |
1862 | if (!*stack_saved) { |
1863 | if (!save_trace(&trace)) | |
1864 | return 0; | |
1865 | *stack_saved = 1; | |
1866 | } | |
4726f2a6 | 1867 | |
fbb9ce95 IM |
1868 | /* |
1869 | * Ok, all validations passed, add the new lock | |
1870 | * to the previous lock's dependency list: | |
1871 | */ | |
f82b217e DJ |
1872 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1873 | &hlock_class(prev)->locks_after, | |
4726f2a6 | 1874 | next->acquire_ip, distance, &trace); |
068135e6 | 1875 | |
fbb9ce95 IM |
1876 | if (!ret) |
1877 | return 0; | |
910b1b2e | 1878 | |
f82b217e DJ |
1879 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1880 | &hlock_class(next)->locks_before, | |
4726f2a6 | 1881 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1882 | if (!ret) |
1883 | return 0; | |
fbb9ce95 IM |
1884 | |
1885 | /* | |
8e18257d PZ |
1886 | * Debugging printouts: |
1887 | */ | |
f82b217e | 1888 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8a5fd564 DV |
1889 | /* We drop graph lock, so another thread can overwrite trace. */ |
1890 | *stack_saved = 0; | |
8e18257d PZ |
1891 | graph_unlock(); |
1892 | printk("\n new dependency: "); | |
f82b217e | 1893 | print_lock_name(hlock_class(prev)); |
8e18257d | 1894 | printk(" => "); |
f82b217e | 1895 | print_lock_name(hlock_class(next)); |
8e18257d | 1896 | printk("\n"); |
fbb9ce95 | 1897 | dump_stack(); |
8e18257d | 1898 | return graph_lock(); |
fbb9ce95 | 1899 | } |
8e18257d PZ |
1900 | return 1; |
1901 | } | |
fbb9ce95 | 1902 | |
8e18257d PZ |
1903 | /* |
1904 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1905 | * The ones that are relevant are (in increasing distance from curr): | |
1906 | * all consecutive trylock entries and the final non-trylock entry - or | |
1907 | * the end of this context's lock-chain - whichever comes first. | |
1908 | */ | |
1909 | static int | |
1910 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1911 | { | |
1912 | int depth = curr->lockdep_depth; | |
8a5fd564 | 1913 | int stack_saved = 0; |
8e18257d | 1914 | struct held_lock *hlock; |
d6d897ce | 1915 | |
fbb9ce95 | 1916 | /* |
8e18257d PZ |
1917 | * Debugging checks. |
1918 | * | |
1919 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1920 | */ |
8e18257d PZ |
1921 | if (!depth) |
1922 | goto out_bug; | |
fbb9ce95 | 1923 | /* |
8e18257d PZ |
1924 | * At least two relevant locks must exist for this |
1925 | * to be a head: | |
fbb9ce95 | 1926 | */ |
8e18257d PZ |
1927 | if (curr->held_locks[depth].irq_context != |
1928 | curr->held_locks[depth-1].irq_context) | |
1929 | goto out_bug; | |
74c383f1 | 1930 | |
8e18257d PZ |
1931 | for (;;) { |
1932 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 1933 | hlock = curr->held_locks + depth - 1; |
8e18257d PZ |
1934 | /* |
1935 | * Only non-recursive-read entries get new dependencies | |
1936 | * added: | |
1937 | */ | |
1b5ff816 | 1938 | if (hlock->read != 2 && hlock->check) { |
4726f2a6 | 1939 | if (!check_prev_add(curr, hlock, next, |
8a5fd564 | 1940 | distance, &stack_saved)) |
8e18257d PZ |
1941 | return 0; |
1942 | /* | |
1943 | * Stop after the first non-trylock entry, | |
1944 | * as non-trylock entries have added their | |
1945 | * own direct dependencies already, so this | |
1946 | * lock is connected to them indirectly: | |
1947 | */ | |
1948 | if (!hlock->trylock) | |
1949 | break; | |
74c383f1 | 1950 | } |
8e18257d PZ |
1951 | depth--; |
1952 | /* | |
1953 | * End of lock-stack? | |
1954 | */ | |
1955 | if (!depth) | |
1956 | break; | |
1957 | /* | |
1958 | * Stop the search if we cross into another context: | |
1959 | */ | |
1960 | if (curr->held_locks[depth].irq_context != | |
1961 | curr->held_locks[depth-1].irq_context) | |
1962 | break; | |
fbb9ce95 | 1963 | } |
8e18257d PZ |
1964 | return 1; |
1965 | out_bug: | |
1966 | if (!debug_locks_off_graph_unlock()) | |
1967 | return 0; | |
fbb9ce95 | 1968 | |
0119fee4 PZ |
1969 | /* |
1970 | * Clearly we all shouldn't be here, but since we made it we | |
1971 | * can reliable say we messed up our state. See the above two | |
1972 | * gotos for reasons why we could possibly end up here. | |
1973 | */ | |
8e18257d | 1974 | WARN_ON(1); |
fbb9ce95 | 1975 | |
8e18257d | 1976 | return 0; |
fbb9ce95 IM |
1977 | } |
1978 | ||
8e18257d | 1979 | unsigned long nr_lock_chains; |
443cd507 | 1980 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1981 | int nr_chain_hlocks; |
443cd507 HY |
1982 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1983 | ||
1984 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1985 | { | |
1986 | return lock_classes + chain_hlocks[chain->base + i]; | |
1987 | } | |
8e18257d | 1988 | |
9e4e7554 IM |
1989 | /* |
1990 | * Returns the index of the first held_lock of the current chain | |
1991 | */ | |
1992 | static inline int get_first_held_lock(struct task_struct *curr, | |
1993 | struct held_lock *hlock) | |
1994 | { | |
1995 | int i; | |
1996 | struct held_lock *hlock_curr; | |
1997 | ||
1998 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1999 | hlock_curr = curr->held_locks + i; | |
2000 | if (hlock_curr->irq_context != hlock->irq_context) | |
2001 | break; | |
2002 | ||
2003 | } | |
2004 | ||
2005 | return ++i; | |
2006 | } | |
2007 | ||
5c8a010c | 2008 | #ifdef CONFIG_DEBUG_LOCKDEP |
39e2e173 AAF |
2009 | /* |
2010 | * Returns the next chain_key iteration | |
2011 | */ | |
2012 | static u64 print_chain_key_iteration(int class_idx, u64 chain_key) | |
2013 | { | |
2014 | u64 new_chain_key = iterate_chain_key(chain_key, class_idx); | |
2015 | ||
2016 | printk(" class_idx:%d -> chain_key:%016Lx", | |
2017 | class_idx, | |
2018 | (unsigned long long)new_chain_key); | |
2019 | return new_chain_key; | |
2020 | } | |
2021 | ||
2022 | static void | |
2023 | print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) | |
2024 | { | |
2025 | struct held_lock *hlock; | |
2026 | u64 chain_key = 0; | |
2027 | int depth = curr->lockdep_depth; | |
2028 | int i; | |
2029 | ||
2030 | printk("depth: %u\n", depth + 1); | |
2031 | for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { | |
2032 | hlock = curr->held_locks + i; | |
2033 | chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); | |
2034 | ||
2035 | print_lock(hlock); | |
2036 | } | |
2037 | ||
2038 | print_chain_key_iteration(hlock_next->class_idx, chain_key); | |
2039 | print_lock(hlock_next); | |
2040 | } | |
2041 | ||
2042 | static void print_chain_keys_chain(struct lock_chain *chain) | |
2043 | { | |
2044 | int i; | |
2045 | u64 chain_key = 0; | |
2046 | int class_id; | |
2047 | ||
2048 | printk("depth: %u\n", chain->depth); | |
2049 | for (i = 0; i < chain->depth; i++) { | |
2050 | class_id = chain_hlocks[chain->base + i]; | |
2051 | chain_key = print_chain_key_iteration(class_id + 1, chain_key); | |
2052 | ||
2053 | print_lock_name(lock_classes + class_id); | |
2054 | printk("\n"); | |
2055 | } | |
2056 | } | |
2057 | ||
2058 | static void print_collision(struct task_struct *curr, | |
2059 | struct held_lock *hlock_next, | |
2060 | struct lock_chain *chain) | |
2061 | { | |
2062 | printk("\n"); | |
2063 | printk("======================\n"); | |
2064 | printk("[chain_key collision ]\n"); | |
2065 | print_kernel_ident(); | |
2066 | printk("----------------------\n"); | |
2067 | printk("%s/%d: ", current->comm, task_pid_nr(current)); | |
2068 | printk("Hash chain already cached but the contents don't match!\n"); | |
2069 | ||
2070 | printk("Held locks:"); | |
2071 | print_chain_keys_held_locks(curr, hlock_next); | |
2072 | ||
2073 | printk("Locks in cached chain:"); | |
2074 | print_chain_keys_chain(chain); | |
2075 | ||
2076 | printk("\nstack backtrace:\n"); | |
2077 | dump_stack(); | |
2078 | } | |
5c8a010c | 2079 | #endif |
39e2e173 | 2080 | |
9e4e7554 IM |
2081 | /* |
2082 | * Checks whether the chain and the current held locks are consistent | |
2083 | * in depth and also in content. If they are not it most likely means | |
2084 | * that there was a collision during the calculation of the chain_key. | |
2085 | * Returns: 0 not passed, 1 passed | |
2086 | */ | |
2087 | static int check_no_collision(struct task_struct *curr, | |
2088 | struct held_lock *hlock, | |
2089 | struct lock_chain *chain) | |
2090 | { | |
2091 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2092 | int i, j, id; | |
2093 | ||
2094 | i = get_first_held_lock(curr, hlock); | |
2095 | ||
39e2e173 AAF |
2096 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { |
2097 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2098 | return 0; |
39e2e173 | 2099 | } |
9e4e7554 IM |
2100 | |
2101 | for (j = 0; j < chain->depth - 1; j++, i++) { | |
2102 | id = curr->held_locks[i].class_idx - 1; | |
2103 | ||
39e2e173 AAF |
2104 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { |
2105 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2106 | return 0; |
39e2e173 | 2107 | } |
9e4e7554 IM |
2108 | } |
2109 | #endif | |
2110 | return 1; | |
2111 | } | |
2112 | ||
fbb9ce95 IM |
2113 | /* |
2114 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
2115 | * add it and return 1 - in this case the new dependency chain is |
2116 | * validated. If the key is already hashed, return 0. | |
2117 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 2118 | */ |
443cd507 HY |
2119 | static inline int lookup_chain_cache(struct task_struct *curr, |
2120 | struct held_lock *hlock, | |
2121 | u64 chain_key) | |
fbb9ce95 | 2122 | { |
f82b217e | 2123 | struct lock_class *class = hlock_class(hlock); |
a63f38cc | 2124 | struct hlist_head *hash_head = chainhashentry(chain_key); |
fbb9ce95 | 2125 | struct lock_chain *chain; |
e0944ee6 | 2126 | int i, j; |
fbb9ce95 | 2127 | |
0119fee4 PZ |
2128 | /* |
2129 | * We might need to take the graph lock, ensure we've got IRQs | |
2130 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2131 | * lockdep won't complain about its own locking errors. | |
2132 | */ | |
381a2292 JP |
2133 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2134 | return 0; | |
fbb9ce95 IM |
2135 | /* |
2136 | * We can walk it lock-free, because entries only get added | |
2137 | * to the hash: | |
2138 | */ | |
a63f38cc | 2139 | hlist_for_each_entry_rcu(chain, hash_head, entry) { |
fbb9ce95 IM |
2140 | if (chain->chain_key == chain_key) { |
2141 | cache_hit: | |
bd6d29c2 | 2142 | debug_atomic_inc(chain_lookup_hits); |
9e4e7554 IM |
2143 | if (!check_no_collision(curr, hlock, chain)) |
2144 | return 0; | |
2145 | ||
81fc685a | 2146 | if (very_verbose(class)) |
755cd900 AM |
2147 | printk("\nhash chain already cached, key: " |
2148 | "%016Lx tail class: [%p] %s\n", | |
2149 | (unsigned long long)chain_key, | |
2150 | class->key, class->name); | |
fbb9ce95 IM |
2151 | return 0; |
2152 | } | |
2153 | } | |
81fc685a | 2154 | if (very_verbose(class)) |
755cd900 AM |
2155 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2156 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2157 | /* |
2158 | * Allocate a new chain entry from the static array, and add | |
2159 | * it to the hash: | |
2160 | */ | |
74c383f1 IM |
2161 | if (!graph_lock()) |
2162 | return 0; | |
fbb9ce95 IM |
2163 | /* |
2164 | * We have to walk the chain again locked - to avoid duplicates: | |
2165 | */ | |
a63f38cc | 2166 | hlist_for_each_entry(chain, hash_head, entry) { |
fbb9ce95 | 2167 | if (chain->chain_key == chain_key) { |
74c383f1 | 2168 | graph_unlock(); |
fbb9ce95 IM |
2169 | goto cache_hit; |
2170 | } | |
2171 | } | |
2172 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2173 | if (!debug_locks_off_graph_unlock()) |
2174 | return 0; | |
2175 | ||
2c522836 | 2176 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2177 | dump_stack(); |
fbb9ce95 IM |
2178 | return 0; |
2179 | } | |
2180 | chain = lock_chains + nr_lock_chains++; | |
2181 | chain->chain_key = chain_key; | |
443cd507 | 2182 | chain->irq_context = hlock->irq_context; |
9e4e7554 | 2183 | i = get_first_held_lock(curr, hlock); |
443cd507 | 2184 | chain->depth = curr->lockdep_depth + 1 - i; |
75dd602a PZ |
2185 | |
2186 | BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks)); | |
2187 | BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks)); | |
2188 | BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes)); | |
2189 | ||
e0944ee6 SR |
2190 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2191 | chain->base = nr_chain_hlocks; | |
443cd507 | 2192 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2193 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2194 | chain_hlocks[chain->base + j] = lock_id; |
2195 | } | |
2196 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2197 | } | |
75dd602a PZ |
2198 | |
2199 | if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS) | |
2200 | nr_chain_hlocks += chain->depth; | |
2201 | ||
2202 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2203 | /* | |
2204 | * Important for check_no_collision(). | |
2205 | */ | |
2206 | if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
2207 | if (debug_locks_off_graph_unlock()) | |
2208 | return 0; | |
2209 | ||
2210 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); | |
2211 | dump_stack(); | |
2212 | return 0; | |
2213 | } | |
2214 | #endif | |
2215 | ||
a63f38cc | 2216 | hlist_add_head_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2217 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2218 | inc_chains(); |
2219 | ||
2220 | return 1; | |
2221 | } | |
2222 | ||
2223 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2224 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2225 | { |
2226 | /* | |
2227 | * Trylock needs to maintain the stack of held locks, but it | |
2228 | * does not add new dependencies, because trylock can be done | |
2229 | * in any order. | |
2230 | * | |
2231 | * We look up the chain_key and do the O(N^2) check and update of | |
2232 | * the dependencies only if this is a new dependency chain. | |
2233 | * (If lookup_chain_cache() returns with 1 it acquires | |
2234 | * graph_lock for us) | |
2235 | */ | |
fb9edbe9 | 2236 | if (!hlock->trylock && hlock->check && |
443cd507 | 2237 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2238 | /* |
2239 | * Check whether last held lock: | |
2240 | * | |
2241 | * - is irq-safe, if this lock is irq-unsafe | |
2242 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2243 | * | |
2244 | * And check whether the new lock's dependency graph | |
2245 | * could lead back to the previous lock. | |
2246 | * | |
2247 | * any of these scenarios could lead to a deadlock. If | |
2248 | * All validations | |
2249 | */ | |
2250 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2251 | ||
2252 | if (!ret) | |
2253 | return 0; | |
2254 | /* | |
2255 | * Mark recursive read, as we jump over it when | |
2256 | * building dependencies (just like we jump over | |
2257 | * trylock entries): | |
2258 | */ | |
2259 | if (ret == 2) | |
2260 | hlock->read = 2; | |
2261 | /* | |
2262 | * Add dependency only if this lock is not the head | |
2263 | * of the chain, and if it's not a secondary read-lock: | |
2264 | */ | |
2265 | if (!chain_head && ret != 2) | |
2266 | if (!check_prevs_add(curr, hlock)) | |
2267 | return 0; | |
2268 | graph_unlock(); | |
2269 | } else | |
2270 | /* after lookup_chain_cache(): */ | |
2271 | if (unlikely(!debug_locks)) | |
2272 | return 0; | |
fbb9ce95 IM |
2273 | |
2274 | return 1; | |
2275 | } | |
8e18257d PZ |
2276 | #else |
2277 | static inline int validate_chain(struct task_struct *curr, | |
2278 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2279 | int chain_head, u64 chain_key) |
8e18257d PZ |
2280 | { |
2281 | return 1; | |
2282 | } | |
ca58abcb | 2283 | #endif |
fbb9ce95 IM |
2284 | |
2285 | /* | |
2286 | * We are building curr_chain_key incrementally, so double-check | |
2287 | * it from scratch, to make sure that it's done correctly: | |
2288 | */ | |
1d09daa5 | 2289 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2290 | { |
2291 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2292 | struct held_lock *hlock, *prev_hlock = NULL; | |
5f18ab5c | 2293 | unsigned int i; |
fbb9ce95 IM |
2294 | u64 chain_key = 0; |
2295 | ||
2296 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2297 | hlock = curr->held_locks + i; | |
2298 | if (chain_key != hlock->prev_chain_key) { | |
2299 | debug_locks_off(); | |
0119fee4 PZ |
2300 | /* |
2301 | * We got mighty confused, our chain keys don't match | |
2302 | * with what we expect, someone trample on our task state? | |
2303 | */ | |
2df8b1d6 | 2304 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2305 | curr->lockdep_depth, i, |
2306 | (unsigned long long)chain_key, | |
2307 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2308 | return; |
2309 | } | |
0119fee4 PZ |
2310 | /* |
2311 | * Whoops ran out of static storage again? | |
2312 | */ | |
5f18ab5c | 2313 | if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) |
381a2292 JP |
2314 | return; |
2315 | ||
fbb9ce95 IM |
2316 | if (prev_hlock && (prev_hlock->irq_context != |
2317 | hlock->irq_context)) | |
2318 | chain_key = 0; | |
5f18ab5c | 2319 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
fbb9ce95 IM |
2320 | prev_hlock = hlock; |
2321 | } | |
2322 | if (chain_key != curr->curr_chain_key) { | |
2323 | debug_locks_off(); | |
0119fee4 PZ |
2324 | /* |
2325 | * More smoking hash instead of calculating it, damn see these | |
2326 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2327 | */ | |
2df8b1d6 | 2328 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2329 | curr->lockdep_depth, i, |
2330 | (unsigned long long)chain_key, | |
2331 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2332 | } |
2333 | #endif | |
2334 | } | |
2335 | ||
282b5c2f SR |
2336 | static void |
2337 | print_usage_bug_scenario(struct held_lock *lock) | |
2338 | { | |
2339 | struct lock_class *class = hlock_class(lock); | |
2340 | ||
2341 | printk(" Possible unsafe locking scenario:\n\n"); | |
2342 | printk(" CPU0\n"); | |
2343 | printk(" ----\n"); | |
2344 | printk(" lock("); | |
2345 | __print_lock_name(class); | |
2346 | printk(");\n"); | |
2347 | printk(" <Interrupt>\n"); | |
2348 | printk(" lock("); | |
2349 | __print_lock_name(class); | |
2350 | printk(");\n"); | |
2351 | printk("\n *** DEADLOCK ***\n\n"); | |
2352 | } | |
2353 | ||
8e18257d PZ |
2354 | static int |
2355 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2356 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2357 | { | |
2358 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2359 | return 0; | |
2360 | ||
b3fbab05 PM |
2361 | printk("\n"); |
2362 | printk("=================================\n"); | |
2363 | printk("[ INFO: inconsistent lock state ]\n"); | |
fbdc4b9a | 2364 | print_kernel_ident(); |
b3fbab05 | 2365 | printk("---------------------------------\n"); |
8e18257d PZ |
2366 | |
2367 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2368 | usage_str[prev_bit], usage_str[new_bit]); | |
2369 | ||
2370 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2371 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2372 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2373 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2374 | trace_hardirqs_enabled(curr), | |
2375 | trace_softirqs_enabled(curr)); | |
2376 | print_lock(this); | |
2377 | ||
2378 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2379 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2380 | |
2381 | print_irqtrace_events(curr); | |
2382 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2383 | print_usage_bug_scenario(this); |
2384 | ||
8e18257d PZ |
2385 | lockdep_print_held_locks(curr); |
2386 | ||
2387 | printk("\nstack backtrace:\n"); | |
2388 | dump_stack(); | |
2389 | ||
2390 | return 0; | |
2391 | } | |
2392 | ||
2393 | /* | |
2394 | * Print out an error if an invalid bit is set: | |
2395 | */ | |
2396 | static inline int | |
2397 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2398 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2399 | { | |
f82b217e | 2400 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2401 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2402 | return 1; | |
2403 | } | |
2404 | ||
2405 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2406 | enum lock_usage_bit new_bit); | |
2407 | ||
81d68a96 | 2408 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2409 | |
2410 | /* | |
2411 | * print irq inversion bug: | |
2412 | */ | |
2413 | static int | |
24208ca7 ML |
2414 | print_irq_inversion_bug(struct task_struct *curr, |
2415 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2416 | struct held_lock *this, int forwards, |
2417 | const char *irqclass) | |
2418 | { | |
dad3d743 SR |
2419 | struct lock_list *entry = other; |
2420 | struct lock_list *middle = NULL; | |
2421 | int depth; | |
2422 | ||
74c383f1 | 2423 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2424 | return 0; |
2425 | ||
b3fbab05 PM |
2426 | printk("\n"); |
2427 | printk("=========================================================\n"); | |
2428 | printk("[ INFO: possible irq lock inversion dependency detected ]\n"); | |
fbdc4b9a | 2429 | print_kernel_ident(); |
b3fbab05 | 2430 | printk("---------------------------------------------------------\n"); |
fbb9ce95 | 2431 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2432 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2433 | print_lock(this); |
2434 | if (forwards) | |
26575e28 | 2435 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2436 | else |
26575e28 | 2437 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2438 | print_lock_name(other->class); |
fbb9ce95 IM |
2439 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2440 | ||
2441 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2442 | |
2443 | /* Find a middle lock (if one exists) */ | |
2444 | depth = get_lock_depth(other); | |
2445 | do { | |
2446 | if (depth == 0 && (entry != root)) { | |
2447 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2448 | break; | |
2449 | } | |
2450 | middle = entry; | |
2451 | entry = get_lock_parent(entry); | |
2452 | depth--; | |
2453 | } while (entry && entry != root && (depth >= 0)); | |
2454 | if (forwards) | |
2455 | print_irq_lock_scenario(root, other, | |
2456 | middle ? middle->class : root->class, other->class); | |
2457 | else | |
2458 | print_irq_lock_scenario(other, root, | |
2459 | middle ? middle->class : other->class, root->class); | |
2460 | ||
fbb9ce95 IM |
2461 | lockdep_print_held_locks(curr); |
2462 | ||
24208ca7 ML |
2463 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2464 | if (!save_trace(&root->trace)) | |
2465 | return 0; | |
2466 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2467 | |
2468 | printk("\nstack backtrace:\n"); | |
2469 | dump_stack(); | |
2470 | ||
2471 | return 0; | |
2472 | } | |
2473 | ||
2474 | /* | |
2475 | * Prove that in the forwards-direction subgraph starting at <this> | |
2476 | * there is no lock matching <mask>: | |
2477 | */ | |
2478 | static int | |
2479 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2480 | enum lock_usage_bit bit, const char *irqclass) | |
2481 | { | |
2482 | int ret; | |
d7aaba14 ML |
2483 | struct lock_list root; |
2484 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2485 | |
d7aaba14 ML |
2486 | root.parent = NULL; |
2487 | root.class = hlock_class(this); | |
2488 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2489 | if (ret < 0) |
2490 | return print_bfs_bug(ret); | |
2491 | if (ret == 1) | |
2492 | return ret; | |
fbb9ce95 | 2493 | |
24208ca7 | 2494 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2495 | this, 1, irqclass); |
fbb9ce95 IM |
2496 | } |
2497 | ||
2498 | /* | |
2499 | * Prove that in the backwards-direction subgraph starting at <this> | |
2500 | * there is no lock matching <mask>: | |
2501 | */ | |
2502 | static int | |
2503 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2504 | enum lock_usage_bit bit, const char *irqclass) | |
2505 | { | |
2506 | int ret; | |
d7aaba14 ML |
2507 | struct lock_list root; |
2508 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2509 | |
d7aaba14 ML |
2510 | root.parent = NULL; |
2511 | root.class = hlock_class(this); | |
2512 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2513 | if (ret < 0) |
2514 | return print_bfs_bug(ret); | |
2515 | if (ret == 1) | |
2516 | return ret; | |
fbb9ce95 | 2517 | |
24208ca7 | 2518 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2519 | this, 0, irqclass); |
fbb9ce95 IM |
2520 | } |
2521 | ||
3117df04 | 2522 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2523 | { |
2524 | printk("irq event stamp: %u\n", curr->irq_events); | |
2525 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2526 | print_ip_sym(curr->hardirq_enable_ip); | |
2527 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2528 | print_ip_sym(curr->hardirq_disable_ip); | |
2529 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2530 | print_ip_sym(curr->softirq_enable_ip); | |
2531 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2532 | print_ip_sym(curr->softirq_disable_ip); | |
2533 | } | |
2534 | ||
cd95302d | 2535 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2536 | { |
8e18257d PZ |
2537 | #if HARDIRQ_VERBOSE |
2538 | return class_filter(class); | |
2539 | #endif | |
fbb9ce95 IM |
2540 | return 0; |
2541 | } | |
2542 | ||
cd95302d | 2543 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2544 | { |
8e18257d PZ |
2545 | #if SOFTIRQ_VERBOSE |
2546 | return class_filter(class); | |
2547 | #endif | |
2548 | return 0; | |
fbb9ce95 IM |
2549 | } |
2550 | ||
cd95302d | 2551 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2552 | { |
2553 | #if RECLAIM_VERBOSE | |
2554 | return class_filter(class); | |
2555 | #endif | |
2556 | return 0; | |
2557 | } | |
2558 | ||
fbb9ce95 IM |
2559 | #define STRICT_READ_CHECKS 1 |
2560 | ||
cd95302d PZ |
2561 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2562 | #define LOCKDEP_STATE(__STATE) \ | |
2563 | __STATE##_verbose, | |
2564 | #include "lockdep_states.h" | |
2565 | #undef LOCKDEP_STATE | |
2566 | }; | |
2567 | ||
2568 | static inline int state_verbose(enum lock_usage_bit bit, | |
2569 | struct lock_class *class) | |
2570 | { | |
2571 | return state_verbose_f[bit >> 2](class); | |
2572 | } | |
2573 | ||
42c50d54 PZ |
2574 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2575 | enum lock_usage_bit bit, const char *name); | |
2576 | ||
6a6904d3 | 2577 | static int |
1c21f14e PZ |
2578 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2579 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2580 | { |
f989209e | 2581 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2582 | int read = new_bit & 1; |
42c50d54 PZ |
2583 | int dir = new_bit & 2; |
2584 | ||
38aa2714 PZ |
2585 | /* |
2586 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2587 | * has ENABLED state, which would allow recursion deadlocks. | |
2588 | * | |
2589 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2590 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2591 | */ | |
42c50d54 PZ |
2592 | check_usage_f usage = dir ? |
2593 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2594 | |
38aa2714 PZ |
2595 | /* |
2596 | * Validate that this particular lock does not have conflicting | |
2597 | * usage states. | |
2598 | */ | |
6a6904d3 PZ |
2599 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2600 | return 0; | |
42c50d54 | 2601 | |
38aa2714 PZ |
2602 | /* |
2603 | * Validate that the lock dependencies don't have conflicting usage | |
2604 | * states. | |
2605 | */ | |
2606 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2607 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2608 | return 0; |
780e820b | 2609 | |
38aa2714 PZ |
2610 | /* |
2611 | * Check for read in write conflicts | |
2612 | */ | |
2613 | if (!read) { | |
2614 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2615 | return 0; | |
2616 | ||
2617 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2618 | !usage(curr, this, excl_bit + 1, |
2619 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2620 | return 0; |
2621 | } | |
780e820b | 2622 | |
cd95302d | 2623 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2624 | return 2; |
2625 | ||
2626 | return 1; | |
2627 | } | |
2628 | ||
cf40bd16 | 2629 | enum mark_type { |
36bfb9bb PZ |
2630 | #define LOCKDEP_STATE(__STATE) __STATE, |
2631 | #include "lockdep_states.h" | |
2632 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2633 | }; |
2634 | ||
fbb9ce95 IM |
2635 | /* |
2636 | * Mark all held locks with a usage bit: | |
2637 | */ | |
1d09daa5 | 2638 | static int |
cf40bd16 | 2639 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2640 | { |
2641 | enum lock_usage_bit usage_bit; | |
2642 | struct held_lock *hlock; | |
2643 | int i; | |
2644 | ||
2645 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2646 | hlock = curr->held_locks + i; | |
2647 | ||
cf2ad4d1 PZ |
2648 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2649 | if (hlock->read) | |
2650 | usage_bit += 1; /* READ */ | |
2651 | ||
2652 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2653 | |
34d0ed5e | 2654 | if (!hlock->check) |
efbe2eee PZ |
2655 | continue; |
2656 | ||
4ff773bb | 2657 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2658 | return 0; |
2659 | } | |
2660 | ||
2661 | return 1; | |
2662 | } | |
2663 | ||
fbb9ce95 IM |
2664 | /* |
2665 | * Hardirqs will be enabled: | |
2666 | */ | |
dd4e5d3a | 2667 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2668 | { |
2669 | struct task_struct *curr = current; | |
fbb9ce95 | 2670 | |
fbb9ce95 IM |
2671 | /* we'll do an OFF -> ON transition: */ |
2672 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2673 | |
fbb9ce95 IM |
2674 | /* |
2675 | * We are going to turn hardirqs on, so set the | |
2676 | * usage bit for all held locks: | |
2677 | */ | |
cf40bd16 | 2678 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2679 | return; |
2680 | /* | |
2681 | * If we have softirqs enabled, then set the usage | |
2682 | * bit for all held locks. (disabled hardirqs prevented | |
2683 | * this bit from being set before) | |
2684 | */ | |
2685 | if (curr->softirqs_enabled) | |
cf40bd16 | 2686 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2687 | return; |
2688 | ||
8e18257d PZ |
2689 | curr->hardirq_enable_ip = ip; |
2690 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2691 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2692 | } |
dd4e5d3a | 2693 | |
b35f8305 | 2694 | __visible void trace_hardirqs_on_caller(unsigned long ip) |
dd4e5d3a PZ |
2695 | { |
2696 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2697 | ||
2698 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2699 | return; | |
2700 | ||
7d36b26b PZ |
2701 | if (unlikely(current->hardirqs_enabled)) { |
2702 | /* | |
2703 | * Neither irq nor preemption are disabled here | |
2704 | * so this is racy by nature but losing one hit | |
2705 | * in a stat is not a big deal. | |
2706 | */ | |
2707 | __debug_atomic_inc(redundant_hardirqs_on); | |
2708 | return; | |
2709 | } | |
2710 | ||
0119fee4 PZ |
2711 | /* |
2712 | * We're enabling irqs and according to our state above irqs weren't | |
2713 | * already enabled, yet we find the hardware thinks they are in fact | |
2714 | * enabled.. someone messed up their IRQ state tracing. | |
2715 | */ | |
dd4e5d3a PZ |
2716 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2717 | return; | |
2718 | ||
0119fee4 PZ |
2719 | /* |
2720 | * See the fine text that goes along with this variable definition. | |
2721 | */ | |
7d36b26b PZ |
2722 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2723 | return; | |
2724 | ||
0119fee4 PZ |
2725 | /* |
2726 | * Can't allow enabling interrupts while in an interrupt handler, | |
2727 | * that's general bad form and such. Recursion, limited stack etc.. | |
2728 | */ | |
7d36b26b PZ |
2729 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2730 | return; | |
2731 | ||
dd4e5d3a PZ |
2732 | current->lockdep_recursion = 1; |
2733 | __trace_hardirqs_on_caller(ip); | |
2734 | current->lockdep_recursion = 0; | |
2735 | } | |
81d68a96 | 2736 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2737 | |
1d09daa5 | 2738 | void trace_hardirqs_on(void) |
81d68a96 SR |
2739 | { |
2740 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2741 | } | |
8e18257d PZ |
2742 | EXPORT_SYMBOL(trace_hardirqs_on); |
2743 | ||
2744 | /* | |
2745 | * Hardirqs were disabled: | |
2746 | */ | |
b35f8305 | 2747 | __visible void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2748 | { |
2749 | struct task_struct *curr = current; | |
2750 | ||
6afe40b4 | 2751 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2752 | |
8e18257d PZ |
2753 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2754 | return; | |
2755 | ||
0119fee4 PZ |
2756 | /* |
2757 | * So we're supposed to get called after you mask local IRQs, but for | |
2758 | * some reason the hardware doesn't quite think you did a proper job. | |
2759 | */ | |
8e18257d PZ |
2760 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2761 | return; | |
2762 | ||
2763 | if (curr->hardirqs_enabled) { | |
2764 | /* | |
2765 | * We have done an ON -> OFF transition: | |
2766 | */ | |
2767 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2768 | curr->hardirq_disable_ip = ip; |
8e18257d | 2769 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2770 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2771 | } else |
bd6d29c2 | 2772 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2773 | } |
81d68a96 | 2774 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2775 | |
1d09daa5 | 2776 | void trace_hardirqs_off(void) |
81d68a96 SR |
2777 | { |
2778 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2779 | } | |
8e18257d PZ |
2780 | EXPORT_SYMBOL(trace_hardirqs_off); |
2781 | ||
2782 | /* | |
2783 | * Softirqs will be enabled: | |
2784 | */ | |
2785 | void trace_softirqs_on(unsigned long ip) | |
2786 | { | |
2787 | struct task_struct *curr = current; | |
2788 | ||
dd4e5d3a | 2789 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2790 | return; |
2791 | ||
0119fee4 PZ |
2792 | /* |
2793 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2794 | * funny state and nesting things. | |
2795 | */ | |
8e18257d PZ |
2796 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2797 | return; | |
2798 | ||
2799 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2800 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2801 | return; |
2802 | } | |
2803 | ||
dd4e5d3a | 2804 | current->lockdep_recursion = 1; |
8e18257d PZ |
2805 | /* |
2806 | * We'll do an OFF -> ON transition: | |
2807 | */ | |
2808 | curr->softirqs_enabled = 1; | |
2809 | curr->softirq_enable_ip = ip; | |
2810 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2811 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2812 | /* |
2813 | * We are going to turn softirqs on, so set the | |
2814 | * usage bit for all held locks, if hardirqs are | |
2815 | * enabled too: | |
2816 | */ | |
2817 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2818 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2819 | current->lockdep_recursion = 0; |
8e18257d PZ |
2820 | } |
2821 | ||
2822 | /* | |
2823 | * Softirqs were disabled: | |
2824 | */ | |
2825 | void trace_softirqs_off(unsigned long ip) | |
2826 | { | |
2827 | struct task_struct *curr = current; | |
2828 | ||
dd4e5d3a | 2829 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2830 | return; |
2831 | ||
0119fee4 PZ |
2832 | /* |
2833 | * We fancy IRQs being disabled here, see softirq.c | |
2834 | */ | |
8e18257d PZ |
2835 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2836 | return; | |
2837 | ||
2838 | if (curr->softirqs_enabled) { | |
2839 | /* | |
2840 | * We have done an ON -> OFF transition: | |
2841 | */ | |
2842 | curr->softirqs_enabled = 0; | |
2843 | curr->softirq_disable_ip = ip; | |
2844 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2845 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
2846 | /* |
2847 | * Whoops, we wanted softirqs off, so why aren't they? | |
2848 | */ | |
8e18257d PZ |
2849 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2850 | } else | |
bd6d29c2 | 2851 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2852 | } |
2853 | ||
2f850181 | 2854 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2855 | { |
2856 | struct task_struct *curr = current; | |
2857 | ||
2858 | if (unlikely(!debug_locks)) | |
2859 | return; | |
2860 | ||
2861 | /* no reclaim without waiting on it */ | |
d0164adc | 2862 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) |
cf40bd16 NP |
2863 | return; |
2864 | ||
2865 | /* this guy won't enter reclaim */ | |
2866 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2867 | return; | |
2868 | ||
2869 | /* We're only interested __GFP_FS allocations for now */ | |
2870 | if (!(gfp_mask & __GFP_FS)) | |
2871 | return; | |
2872 | ||
0119fee4 PZ |
2873 | /* |
2874 | * Oi! Can't be having __GFP_FS allocations with IRQs disabled. | |
2875 | */ | |
2f850181 | 2876 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2877 | return; |
2878 | ||
2879 | mark_held_locks(curr, RECLAIM_FS); | |
2880 | } | |
2881 | ||
2f850181 PZ |
2882 | static void check_flags(unsigned long flags); |
2883 | ||
2884 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2885 | { | |
2886 | unsigned long flags; | |
2887 | ||
2888 | if (unlikely(current->lockdep_recursion)) | |
2889 | return; | |
2890 | ||
2891 | raw_local_irq_save(flags); | |
2892 | check_flags(flags); | |
2893 | current->lockdep_recursion = 1; | |
2894 | __lockdep_trace_alloc(gfp_mask, flags); | |
2895 | current->lockdep_recursion = 0; | |
2896 | raw_local_irq_restore(flags); | |
2897 | } | |
2898 | ||
8e18257d PZ |
2899 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2900 | { | |
2901 | /* | |
2902 | * If non-trylock use in a hardirq or softirq context, then | |
2903 | * mark the lock as used in these contexts: | |
2904 | */ | |
2905 | if (!hlock->trylock) { | |
2906 | if (hlock->read) { | |
2907 | if (curr->hardirq_context) | |
2908 | if (!mark_lock(curr, hlock, | |
2909 | LOCK_USED_IN_HARDIRQ_READ)) | |
2910 | return 0; | |
2911 | if (curr->softirq_context) | |
2912 | if (!mark_lock(curr, hlock, | |
2913 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2914 | return 0; | |
2915 | } else { | |
2916 | if (curr->hardirq_context) | |
2917 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2918 | return 0; | |
2919 | if (curr->softirq_context) | |
2920 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2921 | return 0; | |
2922 | } | |
2923 | } | |
2924 | if (!hlock->hardirqs_off) { | |
2925 | if (hlock->read) { | |
2926 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2927 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2928 | return 0; |
2929 | if (curr->softirqs_enabled) | |
2930 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2931 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2932 | return 0; |
2933 | } else { | |
2934 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2935 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2936 | return 0; |
2937 | if (curr->softirqs_enabled) | |
2938 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2939 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2940 | return 0; |
2941 | } | |
2942 | } | |
2943 | ||
cf40bd16 NP |
2944 | /* |
2945 | * We reuse the irq context infrastructure more broadly as a general | |
2946 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2947 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2948 | * allocation). | |
2949 | */ | |
2950 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2951 | if (hlock->read) { | |
2952 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2953 | return 0; | |
2954 | } else { | |
2955 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2956 | return 0; | |
2957 | } | |
2958 | } | |
2959 | ||
8e18257d PZ |
2960 | return 1; |
2961 | } | |
2962 | ||
c2469756 BF |
2963 | static inline unsigned int task_irq_context(struct task_struct *task) |
2964 | { | |
2965 | return 2 * !!task->hardirq_context + !!task->softirq_context; | |
2966 | } | |
2967 | ||
8e18257d PZ |
2968 | static int separate_irq_context(struct task_struct *curr, |
2969 | struct held_lock *hlock) | |
2970 | { | |
2971 | unsigned int depth = curr->lockdep_depth; | |
2972 | ||
2973 | /* | |
2974 | * Keep track of points where we cross into an interrupt context: | |
2975 | */ | |
8e18257d PZ |
2976 | if (depth) { |
2977 | struct held_lock *prev_hlock; | |
2978 | ||
2979 | prev_hlock = curr->held_locks + depth-1; | |
2980 | /* | |
2981 | * If we cross into another context, reset the | |
2982 | * hash key (this also prevents the checking and the | |
2983 | * adding of the dependency to 'prev'): | |
2984 | */ | |
2985 | if (prev_hlock->irq_context != hlock->irq_context) | |
2986 | return 1; | |
2987 | } | |
2988 | return 0; | |
fbb9ce95 IM |
2989 | } |
2990 | ||
0119fee4 | 2991 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 2992 | |
8e18257d PZ |
2993 | static inline |
2994 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2995 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2996 | { |
0119fee4 | 2997 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
2998 | return 1; |
2999 | } | |
fbb9ce95 | 3000 | |
8e18257d PZ |
3001 | static inline int mark_irqflags(struct task_struct *curr, |
3002 | struct held_lock *hlock) | |
3003 | { | |
3004 | return 1; | |
3005 | } | |
fbb9ce95 | 3006 | |
c2469756 BF |
3007 | static inline unsigned int task_irq_context(struct task_struct *task) |
3008 | { | |
3009 | return 0; | |
3010 | } | |
3011 | ||
8e18257d PZ |
3012 | static inline int separate_irq_context(struct task_struct *curr, |
3013 | struct held_lock *hlock) | |
3014 | { | |
3015 | return 0; | |
fbb9ce95 IM |
3016 | } |
3017 | ||
868a23a8 PZ |
3018 | void lockdep_trace_alloc(gfp_t gfp_mask) |
3019 | { | |
3020 | } | |
3021 | ||
0119fee4 | 3022 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
3023 | |
3024 | /* | |
8e18257d | 3025 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 3026 | */ |
1d09daa5 | 3027 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 3028 | enum lock_usage_bit new_bit) |
fbb9ce95 | 3029 | { |
8e18257d | 3030 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
3031 | |
3032 | /* | |
8e18257d PZ |
3033 | * If already set then do not dirty the cacheline, |
3034 | * nor do any checks: | |
fbb9ce95 | 3035 | */ |
f82b217e | 3036 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
3037 | return 1; |
3038 | ||
3039 | if (!graph_lock()) | |
3040 | return 0; | |
fbb9ce95 | 3041 | /* |
25985edc | 3042 | * Make sure we didn't race: |
fbb9ce95 | 3043 | */ |
f82b217e | 3044 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
3045 | graph_unlock(); |
3046 | return 1; | |
3047 | } | |
fbb9ce95 | 3048 | |
f82b217e | 3049 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 3050 | |
f82b217e | 3051 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 3052 | return 0; |
fbb9ce95 | 3053 | |
8e18257d | 3054 | switch (new_bit) { |
5346417e PZ |
3055 | #define LOCKDEP_STATE(__STATE) \ |
3056 | case LOCK_USED_IN_##__STATE: \ | |
3057 | case LOCK_USED_IN_##__STATE##_READ: \ | |
3058 | case LOCK_ENABLED_##__STATE: \ | |
3059 | case LOCK_ENABLED_##__STATE##_READ: | |
3060 | #include "lockdep_states.h" | |
3061 | #undef LOCKDEP_STATE | |
8e18257d PZ |
3062 | ret = mark_lock_irq(curr, this, new_bit); |
3063 | if (!ret) | |
3064 | return 0; | |
3065 | break; | |
3066 | case LOCK_USED: | |
bd6d29c2 | 3067 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
3068 | break; |
3069 | default: | |
3070 | if (!debug_locks_off_graph_unlock()) | |
3071 | return 0; | |
3072 | WARN_ON(1); | |
3073 | return 0; | |
3074 | } | |
fbb9ce95 | 3075 | |
8e18257d PZ |
3076 | graph_unlock(); |
3077 | ||
3078 | /* | |
3079 | * We must printk outside of the graph_lock: | |
3080 | */ | |
3081 | if (ret == 2) { | |
3082 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
3083 | print_lock(this); | |
3084 | print_irqtrace_events(curr); | |
3085 | dump_stack(); | |
3086 | } | |
3087 | ||
3088 | return ret; | |
3089 | } | |
fbb9ce95 IM |
3090 | |
3091 | /* | |
3092 | * Initialize a lock instance's lock-class mapping info: | |
3093 | */ | |
3094 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 3095 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 3096 | { |
d3d03d4f YZ |
3097 | int i; |
3098 | ||
3099 | kmemcheck_mark_initialized(lock, sizeof(*lock)); | |
3100 | ||
3101 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) | |
3102 | lock->class_cache[i] = NULL; | |
62016250 | 3103 | |
c8a25005 PZ |
3104 | #ifdef CONFIG_LOCK_STAT |
3105 | lock->cpu = raw_smp_processor_id(); | |
3106 | #endif | |
3107 | ||
0119fee4 PZ |
3108 | /* |
3109 | * Can't be having no nameless bastards around this place! | |
3110 | */ | |
c8a25005 PZ |
3111 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
3112 | lock->name = "NULL"; | |
fbb9ce95 | 3113 | return; |
c8a25005 PZ |
3114 | } |
3115 | ||
3116 | lock->name = name; | |
fbb9ce95 | 3117 | |
0119fee4 PZ |
3118 | /* |
3119 | * No key, no joy, we need to hash something. | |
3120 | */ | |
fbb9ce95 IM |
3121 | if (DEBUG_LOCKS_WARN_ON(!key)) |
3122 | return; | |
fbb9ce95 IM |
3123 | /* |
3124 | * Sanity check, the lock-class key must be persistent: | |
3125 | */ | |
3126 | if (!static_obj(key)) { | |
3127 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
3128 | /* |
3129 | * What it says above ^^^^^, I suggest you read it. | |
3130 | */ | |
fbb9ce95 IM |
3131 | DEBUG_LOCKS_WARN_ON(1); |
3132 | return; | |
3133 | } | |
fbb9ce95 | 3134 | lock->key = key; |
c8a25005 PZ |
3135 | |
3136 | if (unlikely(!debug_locks)) | |
3137 | return; | |
3138 | ||
35a9393c PZ |
3139 | if (subclass) { |
3140 | unsigned long flags; | |
3141 | ||
3142 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3143 | return; | |
3144 | ||
3145 | raw_local_irq_save(flags); | |
3146 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3147 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3148 | current->lockdep_recursion = 0; |
3149 | raw_local_irq_restore(flags); | |
3150 | } | |
fbb9ce95 | 3151 | } |
fbb9ce95 IM |
3152 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3153 | ||
1704f47b | 3154 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3155 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3156 | |
d0945950 ML |
3157 | static int |
3158 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3159 | struct held_lock *hlock, | |
3160 | unsigned long ip) | |
3161 | { | |
3162 | if (!debug_locks_off()) | |
3163 | return 0; | |
3164 | if (debug_locks_silent) | |
3165 | return 0; | |
3166 | ||
3167 | printk("\n"); | |
3168 | printk("==================================\n"); | |
3169 | printk("[ BUG: Nested lock was not taken ]\n"); | |
3170 | print_kernel_ident(); | |
3171 | printk("----------------------------------\n"); | |
3172 | ||
3173 | printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); | |
3174 | print_lock(hlock); | |
3175 | ||
3176 | printk("\nbut this task is not holding:\n"); | |
3177 | printk("%s\n", hlock->nest_lock->name); | |
3178 | ||
3179 | printk("\nstack backtrace:\n"); | |
3180 | dump_stack(); | |
3181 | ||
3182 | printk("\nother info that might help us debug this:\n"); | |
3183 | lockdep_print_held_locks(curr); | |
3184 | ||
3185 | printk("\nstack backtrace:\n"); | |
3186 | dump_stack(); | |
3187 | ||
3188 | return 0; | |
3189 | } | |
3190 | ||
3191 | static int __lock_is_held(struct lockdep_map *lock); | |
3192 | ||
fbb9ce95 IM |
3193 | /* |
3194 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3195 | * We maintain the dependency maps and validate the locking attempt: | |
3196 | */ | |
3197 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3198 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3199 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3200 | int references, int pin_count) |
fbb9ce95 IM |
3201 | { |
3202 | struct task_struct *curr = current; | |
d6d897ce | 3203 | struct lock_class *class = NULL; |
fbb9ce95 | 3204 | struct held_lock *hlock; |
5f18ab5c | 3205 | unsigned int depth; |
fbb9ce95 | 3206 | int chain_head = 0; |
bb97a91e | 3207 | int class_idx; |
fbb9ce95 IM |
3208 | u64 chain_key; |
3209 | ||
3210 | if (unlikely(!debug_locks)) | |
3211 | return 0; | |
3212 | ||
0119fee4 PZ |
3213 | /* |
3214 | * Lockdep should run with IRQs disabled, otherwise we could | |
3215 | * get an interrupt which would want to take locks, which would | |
3216 | * end up in lockdep and have you got a head-ache already? | |
3217 | */ | |
fbb9ce95 IM |
3218 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3219 | return 0; | |
3220 | ||
fb9edbe9 ON |
3221 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3222 | check = 0; | |
1704f47b | 3223 | |
62016250 HM |
3224 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3225 | class = lock->class_cache[subclass]; | |
d6d897ce | 3226 | /* |
62016250 | 3227 | * Not cached? |
d6d897ce | 3228 | */ |
fbb9ce95 | 3229 | if (unlikely(!class)) { |
4dfbb9d8 | 3230 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3231 | if (!class) |
3232 | return 0; | |
3233 | } | |
bd6d29c2 | 3234 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3235 | if (very_verbose(class)) { |
3236 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3237 | if (class->name_version > 1) | |
3238 | printk("#%d", class->name_version); | |
3239 | printk("\n"); | |
3240 | dump_stack(); | |
3241 | } | |
3242 | ||
3243 | /* | |
3244 | * Add the lock to the list of currently held locks. | |
3245 | * (we dont increase the depth just yet, up until the | |
3246 | * dependency checks are done) | |
3247 | */ | |
3248 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3249 | /* |
3250 | * Ran out of static storage for our per-task lock stack again have we? | |
3251 | */ | |
fbb9ce95 IM |
3252 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3253 | return 0; | |
3254 | ||
bb97a91e PZ |
3255 | class_idx = class - lock_classes + 1; |
3256 | ||
3257 | if (depth) { | |
3258 | hlock = curr->held_locks + depth - 1; | |
3259 | if (hlock->class_idx == class_idx && nest_lock) { | |
3260 | if (hlock->references) | |
3261 | hlock->references++; | |
3262 | else | |
3263 | hlock->references = 2; | |
3264 | ||
3265 | return 1; | |
3266 | } | |
3267 | } | |
3268 | ||
fbb9ce95 | 3269 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3270 | /* |
3271 | * Plain impossible, we just registered it and checked it weren't no | |
3272 | * NULL like.. I bet this mushroom I ate was good! | |
3273 | */ | |
f82b217e DJ |
3274 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3275 | return 0; | |
bb97a91e | 3276 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3277 | hlock->acquire_ip = ip; |
3278 | hlock->instance = lock; | |
7531e2f3 | 3279 | hlock->nest_lock = nest_lock; |
c2469756 | 3280 | hlock->irq_context = task_irq_context(curr); |
fbb9ce95 IM |
3281 | hlock->trylock = trylock; |
3282 | hlock->read = read; | |
3283 | hlock->check = check; | |
6951b12a | 3284 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3285 | hlock->references = references; |
f20786ff PZ |
3286 | #ifdef CONFIG_LOCK_STAT |
3287 | hlock->waittime_stamp = 0; | |
3365e779 | 3288 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3289 | #endif |
21199f27 | 3290 | hlock->pin_count = pin_count; |
fbb9ce95 | 3291 | |
fb9edbe9 | 3292 | if (check && !mark_irqflags(curr, hlock)) |
8e18257d PZ |
3293 | return 0; |
3294 | ||
fbb9ce95 | 3295 | /* mark it as used: */ |
4ff773bb | 3296 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3297 | return 0; |
8e18257d | 3298 | |
fbb9ce95 | 3299 | /* |
17aacfb9 | 3300 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3301 | * lock keys along the dependency chain. We save the hash value |
3302 | * at every step so that we can get the current hash easily | |
3303 | * after unlock. The chain hash is then used to cache dependency | |
3304 | * results. | |
3305 | * | |
3306 | * The 'key ID' is what is the most compact key value to drive | |
3307 | * the hash, not class->key. | |
3308 | */ | |
0119fee4 PZ |
3309 | /* |
3310 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3311 | */ | |
5f18ab5c | 3312 | if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) |
fbb9ce95 IM |
3313 | return 0; |
3314 | ||
3315 | chain_key = curr->curr_chain_key; | |
3316 | if (!depth) { | |
0119fee4 PZ |
3317 | /* |
3318 | * How can we have a chain hash when we ain't got no keys?! | |
3319 | */ | |
fbb9ce95 IM |
3320 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3321 | return 0; | |
3322 | chain_head = 1; | |
3323 | } | |
3324 | ||
3325 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3326 | if (separate_irq_context(curr, hlock)) { |
3327 | chain_key = 0; | |
3328 | chain_head = 1; | |
fbb9ce95 | 3329 | } |
5f18ab5c | 3330 | chain_key = iterate_chain_key(chain_key, class_idx); |
fbb9ce95 | 3331 | |
d0945950 ML |
3332 | if (nest_lock && !__lock_is_held(nest_lock)) |
3333 | return print_lock_nested_lock_not_held(curr, hlock, ip); | |
3334 | ||
3aa416b0 | 3335 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3336 | return 0; |
381a2292 | 3337 | |
3aa416b0 | 3338 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3339 | curr->lockdep_depth++; |
3340 | check_chain_key(curr); | |
60e114d1 JP |
3341 | #ifdef CONFIG_DEBUG_LOCKDEP |
3342 | if (unlikely(!debug_locks)) | |
3343 | return 0; | |
3344 | #endif | |
fbb9ce95 IM |
3345 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3346 | debug_locks_off(); | |
2c522836 DJ |
3347 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3348 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3349 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3350 | |
3351 | lockdep_print_held_locks(current); | |
3352 | debug_show_all_locks(); | |
eedeeabd | 3353 | dump_stack(); |
c0540606 | 3354 | |
fbb9ce95 IM |
3355 | return 0; |
3356 | } | |
381a2292 | 3357 | |
fbb9ce95 IM |
3358 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3359 | max_lockdep_depth = curr->lockdep_depth; | |
3360 | ||
3361 | return 1; | |
3362 | } | |
3363 | ||
3364 | static int | |
f86f7554 | 3365 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3366 | unsigned long ip) |
3367 | { | |
3368 | if (!debug_locks_off()) | |
3369 | return 0; | |
3370 | if (debug_locks_silent) | |
3371 | return 0; | |
3372 | ||
b3fbab05 PM |
3373 | printk("\n"); |
3374 | printk("=====================================\n"); | |
3375 | printk("[ BUG: bad unlock balance detected! ]\n"); | |
fbdc4b9a | 3376 | print_kernel_ident(); |
b3fbab05 | 3377 | printk("-------------------------------------\n"); |
fbb9ce95 | 3378 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3379 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3380 | print_lockdep_cache(lock); |
3381 | printk(") at:\n"); | |
3382 | print_ip_sym(ip); | |
3383 | printk("but there are no more locks to release!\n"); | |
3384 | printk("\nother info that might help us debug this:\n"); | |
3385 | lockdep_print_held_locks(curr); | |
3386 | ||
3387 | printk("\nstack backtrace:\n"); | |
3388 | dump_stack(); | |
3389 | ||
3390 | return 0; | |
3391 | } | |
3392 | ||
bb97a91e PZ |
3393 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3394 | { | |
3395 | if (hlock->instance == lock) | |
3396 | return 1; | |
3397 | ||
3398 | if (hlock->references) { | |
62016250 | 3399 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3400 | |
3401 | if (!class) | |
3402 | class = look_up_lock_class(lock, 0); | |
3403 | ||
80e0401e PZ |
3404 | /* |
3405 | * If look_up_lock_class() failed to find a class, we're trying | |
3406 | * to test if we hold a lock that has never yet been acquired. | |
3407 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3408 | * holding it either, so report failure. | |
3409 | */ | |
3410 | if (!class) | |
bb97a91e PZ |
3411 | return 0; |
3412 | ||
0119fee4 PZ |
3413 | /* |
3414 | * References, but not a lock we're actually ref-counting? | |
3415 | * State got messed up, follow the sites that change ->references | |
3416 | * and try to make sense of it. | |
3417 | */ | |
bb97a91e PZ |
3418 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3419 | return 0; | |
3420 | ||
3421 | if (hlock->class_idx == class - lock_classes + 1) | |
3422 | return 1; | |
3423 | } | |
3424 | ||
3425 | return 0; | |
3426 | } | |
3427 | ||
64aa348e | 3428 | static int |
00ef9f73 PZ |
3429 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3430 | struct lock_class_key *key, unsigned int subclass, | |
3431 | unsigned long ip) | |
64aa348e PZ |
3432 | { |
3433 | struct task_struct *curr = current; | |
3434 | struct held_lock *hlock, *prev_hlock; | |
3435 | struct lock_class *class; | |
3436 | unsigned int depth; | |
3437 | int i; | |
3438 | ||
3439 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3440 | /* |
3441 | * This function is about (re)setting the class of a held lock, | |
3442 | * yet we're not actually holding any locks. Naughty user! | |
3443 | */ | |
64aa348e PZ |
3444 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3445 | return 0; | |
3446 | ||
3447 | prev_hlock = NULL; | |
3448 | for (i = depth-1; i >= 0; i--) { | |
3449 | hlock = curr->held_locks + i; | |
3450 | /* | |
3451 | * We must not cross into another context: | |
3452 | */ | |
3453 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3454 | break; | |
bb97a91e | 3455 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3456 | goto found_it; |
3457 | prev_hlock = hlock; | |
3458 | } | |
f86f7554 | 3459 | return print_unlock_imbalance_bug(curr, lock, ip); |
64aa348e PZ |
3460 | |
3461 | found_it: | |
00ef9f73 | 3462 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3463 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3464 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3465 | |
3466 | curr->lockdep_depth = i; | |
3467 | curr->curr_chain_key = hlock->prev_chain_key; | |
3468 | ||
3469 | for (; i < depth; i++) { | |
3470 | hlock = curr->held_locks + i; | |
3471 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3472 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3473 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3474 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3475 | hlock->references, hlock->pin_count)) |
64aa348e PZ |
3476 | return 0; |
3477 | } | |
3478 | ||
0119fee4 PZ |
3479 | /* |
3480 | * I took it apart and put it back together again, except now I have | |
3481 | * these 'spare' parts.. where shall I put them. | |
3482 | */ | |
64aa348e PZ |
3483 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3484 | return 0; | |
3485 | return 1; | |
3486 | } | |
3487 | ||
fbb9ce95 | 3488 | /* |
e0f56fd7 PZ |
3489 | * Remove the lock to the list of currently held locks - this gets |
3490 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3491 | * mutex_lock_interruptible()). | |
3492 | * | |
3493 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
3494 | */ |
3495 | static int | |
e0f56fd7 | 3496 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
fbb9ce95 | 3497 | { |
e0f56fd7 | 3498 | struct task_struct *curr = current; |
fbb9ce95 IM |
3499 | struct held_lock *hlock, *prev_hlock; |
3500 | unsigned int depth; | |
3501 | int i; | |
3502 | ||
e0f56fd7 PZ |
3503 | if (unlikely(!debug_locks)) |
3504 | return 0; | |
3505 | ||
fbb9ce95 | 3506 | depth = curr->lockdep_depth; |
0119fee4 PZ |
3507 | /* |
3508 | * So we're all set to release this lock.. wait what lock? We don't | |
3509 | * own any locks, you've been drinking again? | |
3510 | */ | |
e0f56fd7 PZ |
3511 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
3512 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3513 | |
e0f56fd7 PZ |
3514 | /* |
3515 | * Check whether the lock exists in the current stack | |
3516 | * of held locks: | |
3517 | */ | |
fbb9ce95 IM |
3518 | prev_hlock = NULL; |
3519 | for (i = depth-1; i >= 0; i--) { | |
3520 | hlock = curr->held_locks + i; | |
3521 | /* | |
3522 | * We must not cross into another context: | |
3523 | */ | |
3524 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3525 | break; | |
bb97a91e | 3526 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3527 | goto found_it; |
3528 | prev_hlock = hlock; | |
3529 | } | |
f86f7554 | 3530 | return print_unlock_imbalance_bug(curr, lock, ip); |
fbb9ce95 IM |
3531 | |
3532 | found_it: | |
bb97a91e PZ |
3533 | if (hlock->instance == lock) |
3534 | lock_release_holdtime(hlock); | |
3535 | ||
a24fc60d PZ |
3536 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
3537 | ||
bb97a91e PZ |
3538 | if (hlock->references) { |
3539 | hlock->references--; | |
3540 | if (hlock->references) { | |
3541 | /* | |
3542 | * We had, and after removing one, still have | |
3543 | * references, the current lock stack is still | |
3544 | * valid. We're done! | |
3545 | */ | |
3546 | return 1; | |
3547 | } | |
3548 | } | |
f20786ff | 3549 | |
fbb9ce95 IM |
3550 | /* |
3551 | * We have the right lock to unlock, 'hlock' points to it. | |
3552 | * Now we remove it from the stack, and add back the other | |
3553 | * entries (if any), recalculating the hash along the way: | |
3554 | */ | |
bb97a91e | 3555 | |
fbb9ce95 IM |
3556 | curr->lockdep_depth = i; |
3557 | curr->curr_chain_key = hlock->prev_chain_key; | |
3558 | ||
3559 | for (i++; i < depth; i++) { | |
3560 | hlock = curr->held_locks + i; | |
3561 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3562 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3563 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3564 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3565 | hlock->references, hlock->pin_count)) |
fbb9ce95 IM |
3566 | return 0; |
3567 | } | |
3568 | ||
0119fee4 PZ |
3569 | /* |
3570 | * We had N bottles of beer on the wall, we drank one, but now | |
3571 | * there's not N-1 bottles of beer left on the wall... | |
3572 | */ | |
fbb9ce95 IM |
3573 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3574 | return 0; | |
f20786ff | 3575 | |
fbb9ce95 IM |
3576 | return 1; |
3577 | } | |
3578 | ||
f607c668 | 3579 | static int __lock_is_held(struct lockdep_map *lock) |
fbb9ce95 | 3580 | { |
f607c668 PZ |
3581 | struct task_struct *curr = current; |
3582 | int i; | |
fbb9ce95 | 3583 | |
f607c668 | 3584 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 3585 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 3586 | |
bb97a91e | 3587 | if (match_held_lock(hlock, lock)) |
f607c668 PZ |
3588 | return 1; |
3589 | } | |
f20786ff | 3590 | |
f607c668 | 3591 | return 0; |
fbb9ce95 IM |
3592 | } |
3593 | ||
e7904a28 PZ |
3594 | static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) |
3595 | { | |
3596 | struct pin_cookie cookie = NIL_COOKIE; | |
3597 | struct task_struct *curr = current; | |
3598 | int i; | |
3599 | ||
3600 | if (unlikely(!debug_locks)) | |
3601 | return cookie; | |
3602 | ||
3603 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3604 | struct held_lock *hlock = curr->held_locks + i; | |
3605 | ||
3606 | if (match_held_lock(hlock, lock)) { | |
3607 | /* | |
3608 | * Grab 16bits of randomness; this is sufficient to not | |
3609 | * be guessable and still allows some pin nesting in | |
3610 | * our u32 pin_count. | |
3611 | */ | |
3612 | cookie.val = 1 + (prandom_u32() >> 16); | |
3613 | hlock->pin_count += cookie.val; | |
3614 | return cookie; | |
3615 | } | |
3616 | } | |
3617 | ||
3618 | WARN(1, "pinning an unheld lock\n"); | |
3619 | return cookie; | |
3620 | } | |
3621 | ||
3622 | static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
fbb9ce95 IM |
3623 | { |
3624 | struct task_struct *curr = current; | |
a24fc60d | 3625 | int i; |
fbb9ce95 | 3626 | |
a24fc60d | 3627 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
3628 | return; |
3629 | ||
a24fc60d PZ |
3630 | for (i = 0; i < curr->lockdep_depth; i++) { |
3631 | struct held_lock *hlock = curr->held_locks + i; | |
3632 | ||
3633 | if (match_held_lock(hlock, lock)) { | |
e7904a28 | 3634 | hlock->pin_count += cookie.val; |
fbb9ce95 | 3635 | return; |
a24fc60d | 3636 | } |
fbb9ce95 IM |
3637 | } |
3638 | ||
a24fc60d | 3639 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
3640 | } |
3641 | ||
e7904a28 | 3642 | static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
f607c668 PZ |
3643 | { |
3644 | struct task_struct *curr = current; | |
3645 | int i; | |
3646 | ||
a24fc60d PZ |
3647 | if (unlikely(!debug_locks)) |
3648 | return; | |
3649 | ||
f607c668 | 3650 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
3651 | struct held_lock *hlock = curr->held_locks + i; |
3652 | ||
a24fc60d PZ |
3653 | if (match_held_lock(hlock, lock)) { |
3654 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
3655 | return; | |
3656 | ||
e7904a28 PZ |
3657 | hlock->pin_count -= cookie.val; |
3658 | ||
3659 | if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n")) | |
3660 | hlock->pin_count = 0; | |
3661 | ||
a24fc60d PZ |
3662 | return; |
3663 | } | |
f607c668 PZ |
3664 | } |
3665 | ||
a24fc60d | 3666 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
3667 | } |
3668 | ||
fbb9ce95 IM |
3669 | /* |
3670 | * Check whether we follow the irq-flags state precisely: | |
3671 | */ | |
1d09daa5 | 3672 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3673 | { |
992860e9 IM |
3674 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3675 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3676 | if (!debug_locks) |
3677 | return; | |
3678 | ||
5f9fa8a6 IM |
3679 | if (irqs_disabled_flags(flags)) { |
3680 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3681 | printk("possible reason: unannotated irqs-off.\n"); | |
3682 | } | |
3683 | } else { | |
3684 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3685 | printk("possible reason: unannotated irqs-on.\n"); | |
3686 | } | |
3687 | } | |
fbb9ce95 IM |
3688 | |
3689 | /* | |
3690 | * We dont accurately track softirq state in e.g. | |
3691 | * hardirq contexts (such as on 4KSTACKS), so only | |
3692 | * check if not in hardirq contexts: | |
3693 | */ | |
3694 | if (!hardirq_count()) { | |
0119fee4 PZ |
3695 | if (softirq_count()) { |
3696 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3697 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3698 | } else { |
3699 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3700 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3701 | } |
fbb9ce95 IM |
3702 | } |
3703 | ||
3704 | if (!debug_locks) | |
3705 | print_irqtrace_events(current); | |
3706 | #endif | |
3707 | } | |
3708 | ||
00ef9f73 PZ |
3709 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3710 | struct lock_class_key *key, unsigned int subclass, | |
3711 | unsigned long ip) | |
64aa348e PZ |
3712 | { |
3713 | unsigned long flags; | |
3714 | ||
3715 | if (unlikely(current->lockdep_recursion)) | |
3716 | return; | |
3717 | ||
3718 | raw_local_irq_save(flags); | |
3719 | current->lockdep_recursion = 1; | |
3720 | check_flags(flags); | |
00ef9f73 | 3721 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3722 | check_chain_key(current); |
3723 | current->lockdep_recursion = 0; | |
3724 | raw_local_irq_restore(flags); | |
3725 | } | |
00ef9f73 | 3726 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3727 | |
fbb9ce95 IM |
3728 | /* |
3729 | * We are not always called with irqs disabled - do that here, | |
3730 | * and also avoid lockdep recursion: | |
3731 | */ | |
1d09daa5 | 3732 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3733 | int trylock, int read, int check, |
3734 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3735 | { |
3736 | unsigned long flags; | |
3737 | ||
3738 | if (unlikely(current->lockdep_recursion)) | |
3739 | return; | |
3740 | ||
3741 | raw_local_irq_save(flags); | |
3742 | check_flags(flags); | |
3743 | ||
3744 | current->lockdep_recursion = 1; | |
db2c4c77 | 3745 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3746 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 3747 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
3748 | current->lockdep_recursion = 0; |
3749 | raw_local_irq_restore(flags); | |
3750 | } | |
fbb9ce95 IM |
3751 | EXPORT_SYMBOL_GPL(lock_acquire); |
3752 | ||
1d09daa5 | 3753 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3754 | unsigned long ip) |
fbb9ce95 IM |
3755 | { |
3756 | unsigned long flags; | |
3757 | ||
3758 | if (unlikely(current->lockdep_recursion)) | |
3759 | return; | |
3760 | ||
3761 | raw_local_irq_save(flags); | |
3762 | check_flags(flags); | |
3763 | current->lockdep_recursion = 1; | |
93135439 | 3764 | trace_lock_release(lock, ip); |
e0f56fd7 PZ |
3765 | if (__lock_release(lock, nested, ip)) |
3766 | check_chain_key(current); | |
fbb9ce95 IM |
3767 | current->lockdep_recursion = 0; |
3768 | raw_local_irq_restore(flags); | |
3769 | } | |
fbb9ce95 IM |
3770 | EXPORT_SYMBOL_GPL(lock_release); |
3771 | ||
f607c668 PZ |
3772 | int lock_is_held(struct lockdep_map *lock) |
3773 | { | |
3774 | unsigned long flags; | |
3775 | int ret = 0; | |
3776 | ||
3777 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3778 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3779 | |
3780 | raw_local_irq_save(flags); | |
3781 | check_flags(flags); | |
3782 | ||
3783 | current->lockdep_recursion = 1; | |
3784 | ret = __lock_is_held(lock); | |
3785 | current->lockdep_recursion = 0; | |
3786 | raw_local_irq_restore(flags); | |
3787 | ||
3788 | return ret; | |
3789 | } | |
3790 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3791 | ||
e7904a28 | 3792 | struct pin_cookie lock_pin_lock(struct lockdep_map *lock) |
a24fc60d | 3793 | { |
e7904a28 | 3794 | struct pin_cookie cookie = NIL_COOKIE; |
a24fc60d PZ |
3795 | unsigned long flags; |
3796 | ||
3797 | if (unlikely(current->lockdep_recursion)) | |
e7904a28 | 3798 | return cookie; |
a24fc60d PZ |
3799 | |
3800 | raw_local_irq_save(flags); | |
3801 | check_flags(flags); | |
3802 | ||
3803 | current->lockdep_recursion = 1; | |
e7904a28 | 3804 | cookie = __lock_pin_lock(lock); |
a24fc60d PZ |
3805 | current->lockdep_recursion = 0; |
3806 | raw_local_irq_restore(flags); | |
e7904a28 PZ |
3807 | |
3808 | return cookie; | |
a24fc60d PZ |
3809 | } |
3810 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
3811 | ||
e7904a28 PZ |
3812 | void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
3813 | { | |
3814 | unsigned long flags; | |
3815 | ||
3816 | if (unlikely(current->lockdep_recursion)) | |
3817 | return; | |
3818 | ||
3819 | raw_local_irq_save(flags); | |
3820 | check_flags(flags); | |
3821 | ||
3822 | current->lockdep_recursion = 1; | |
3823 | __lock_repin_lock(lock, cookie); | |
3824 | current->lockdep_recursion = 0; | |
3825 | raw_local_irq_restore(flags); | |
3826 | } | |
3827 | EXPORT_SYMBOL_GPL(lock_repin_lock); | |
3828 | ||
3829 | void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
a24fc60d PZ |
3830 | { |
3831 | unsigned long flags; | |
3832 | ||
3833 | if (unlikely(current->lockdep_recursion)) | |
3834 | return; | |
3835 | ||
3836 | raw_local_irq_save(flags); | |
3837 | check_flags(flags); | |
3838 | ||
3839 | current->lockdep_recursion = 1; | |
e7904a28 | 3840 | __lock_unpin_lock(lock, cookie); |
a24fc60d PZ |
3841 | current->lockdep_recursion = 0; |
3842 | raw_local_irq_restore(flags); | |
3843 | } | |
3844 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
3845 | ||
cf40bd16 NP |
3846 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3847 | { | |
3848 | current->lockdep_reclaim_gfp = gfp_mask; | |
3849 | } | |
3850 | ||
3851 | void lockdep_clear_current_reclaim_state(void) | |
3852 | { | |
3853 | current->lockdep_reclaim_gfp = 0; | |
3854 | } | |
3855 | ||
f20786ff PZ |
3856 | #ifdef CONFIG_LOCK_STAT |
3857 | static int | |
3858 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3859 | unsigned long ip) | |
3860 | { | |
3861 | if (!debug_locks_off()) | |
3862 | return 0; | |
3863 | if (debug_locks_silent) | |
3864 | return 0; | |
3865 | ||
b3fbab05 PM |
3866 | printk("\n"); |
3867 | printk("=================================\n"); | |
3868 | printk("[ BUG: bad contention detected! ]\n"); | |
fbdc4b9a | 3869 | print_kernel_ident(); |
b3fbab05 | 3870 | printk("---------------------------------\n"); |
f20786ff | 3871 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3872 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3873 | print_lockdep_cache(lock); |
3874 | printk(") at:\n"); | |
3875 | print_ip_sym(ip); | |
3876 | printk("but there are no locks held!\n"); | |
3877 | printk("\nother info that might help us debug this:\n"); | |
3878 | lockdep_print_held_locks(curr); | |
3879 | ||
3880 | printk("\nstack backtrace:\n"); | |
3881 | dump_stack(); | |
3882 | ||
3883 | return 0; | |
3884 | } | |
3885 | ||
3886 | static void | |
3887 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3888 | { | |
3889 | struct task_struct *curr = current; | |
3890 | struct held_lock *hlock, *prev_hlock; | |
3891 | struct lock_class_stats *stats; | |
3892 | unsigned int depth; | |
c7e78cff | 3893 | int i, contention_point, contending_point; |
f20786ff PZ |
3894 | |
3895 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3896 | /* |
3897 | * Whee, we contended on this lock, except it seems we're not | |
3898 | * actually trying to acquire anything much at all.. | |
3899 | */ | |
f20786ff PZ |
3900 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3901 | return; | |
3902 | ||
3903 | prev_hlock = NULL; | |
3904 | for (i = depth-1; i >= 0; i--) { | |
3905 | hlock = curr->held_locks + i; | |
3906 | /* | |
3907 | * We must not cross into another context: | |
3908 | */ | |
3909 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3910 | break; | |
bb97a91e | 3911 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3912 | goto found_it; |
3913 | prev_hlock = hlock; | |
3914 | } | |
3915 | print_lock_contention_bug(curr, lock, ip); | |
3916 | return; | |
3917 | ||
3918 | found_it: | |
bb97a91e PZ |
3919 | if (hlock->instance != lock) |
3920 | return; | |
3921 | ||
3365e779 | 3922 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3923 | |
c7e78cff PZ |
3924 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3925 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3926 | lock->ip); | |
f20786ff | 3927 | |
f82b217e | 3928 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3929 | if (contention_point < LOCKSTAT_POINTS) |
3930 | stats->contention_point[contention_point]++; | |
3931 | if (contending_point < LOCKSTAT_POINTS) | |
3932 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3933 | if (lock->cpu != smp_processor_id()) |
3934 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3935 | put_lock_stats(stats); |
3936 | } | |
3937 | ||
3938 | static void | |
c7e78cff | 3939 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3940 | { |
3941 | struct task_struct *curr = current; | |
3942 | struct held_lock *hlock, *prev_hlock; | |
3943 | struct lock_class_stats *stats; | |
3944 | unsigned int depth; | |
3365e779 | 3945 | u64 now, waittime = 0; |
96645678 | 3946 | int i, cpu; |
f20786ff PZ |
3947 | |
3948 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3949 | /* |
3950 | * Yay, we acquired ownership of this lock we didn't try to | |
3951 | * acquire, how the heck did that happen? | |
3952 | */ | |
f20786ff PZ |
3953 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3954 | return; | |
3955 | ||
3956 | prev_hlock = NULL; | |
3957 | for (i = depth-1; i >= 0; i--) { | |
3958 | hlock = curr->held_locks + i; | |
3959 | /* | |
3960 | * We must not cross into another context: | |
3961 | */ | |
3962 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3963 | break; | |
bb97a91e | 3964 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3965 | goto found_it; |
3966 | prev_hlock = hlock; | |
3967 | } | |
3968 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3969 | return; | |
3970 | ||
3971 | found_it: | |
bb97a91e PZ |
3972 | if (hlock->instance != lock) |
3973 | return; | |
3974 | ||
96645678 PZ |
3975 | cpu = smp_processor_id(); |
3976 | if (hlock->waittime_stamp) { | |
3365e779 | 3977 | now = lockstat_clock(); |
96645678 PZ |
3978 | waittime = now - hlock->waittime_stamp; |
3979 | hlock->holdtime_stamp = now; | |
3980 | } | |
f20786ff | 3981 | |
883a2a31 | 3982 | trace_lock_acquired(lock, ip); |
2062501a | 3983 | |
f82b217e | 3984 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3985 | if (waittime) { |
3986 | if (hlock->read) | |
3987 | lock_time_inc(&stats->read_waittime, waittime); | |
3988 | else | |
3989 | lock_time_inc(&stats->write_waittime, waittime); | |
3990 | } | |
3991 | if (lock->cpu != cpu) | |
3992 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3993 | put_lock_stats(stats); |
96645678 PZ |
3994 | |
3995 | lock->cpu = cpu; | |
c7e78cff | 3996 | lock->ip = ip; |
f20786ff PZ |
3997 | } |
3998 | ||
3999 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4000 | { | |
4001 | unsigned long flags; | |
4002 | ||
4003 | if (unlikely(!lock_stat)) | |
4004 | return; | |
4005 | ||
4006 | if (unlikely(current->lockdep_recursion)) | |
4007 | return; | |
4008 | ||
4009 | raw_local_irq_save(flags); | |
4010 | check_flags(flags); | |
4011 | current->lockdep_recursion = 1; | |
db2c4c77 | 4012 | trace_lock_contended(lock, ip); |
f20786ff PZ |
4013 | __lock_contended(lock, ip); |
4014 | current->lockdep_recursion = 0; | |
4015 | raw_local_irq_restore(flags); | |
4016 | } | |
4017 | EXPORT_SYMBOL_GPL(lock_contended); | |
4018 | ||
c7e78cff | 4019 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4020 | { |
4021 | unsigned long flags; | |
4022 | ||
4023 | if (unlikely(!lock_stat)) | |
4024 | return; | |
4025 | ||
4026 | if (unlikely(current->lockdep_recursion)) | |
4027 | return; | |
4028 | ||
4029 | raw_local_irq_save(flags); | |
4030 | check_flags(flags); | |
4031 | current->lockdep_recursion = 1; | |
c7e78cff | 4032 | __lock_acquired(lock, ip); |
f20786ff PZ |
4033 | current->lockdep_recursion = 0; |
4034 | raw_local_irq_restore(flags); | |
4035 | } | |
4036 | EXPORT_SYMBOL_GPL(lock_acquired); | |
4037 | #endif | |
4038 | ||
fbb9ce95 IM |
4039 | /* |
4040 | * Used by the testsuite, sanitize the validator state | |
4041 | * after a simulated failure: | |
4042 | */ | |
4043 | ||
4044 | void lockdep_reset(void) | |
4045 | { | |
4046 | unsigned long flags; | |
23d95a03 | 4047 | int i; |
fbb9ce95 IM |
4048 | |
4049 | raw_local_irq_save(flags); | |
4050 | current->curr_chain_key = 0; | |
4051 | current->lockdep_depth = 0; | |
4052 | current->lockdep_recursion = 0; | |
4053 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
4054 | nr_hardirq_chains = 0; | |
4055 | nr_softirq_chains = 0; | |
4056 | nr_process_chains = 0; | |
4057 | debug_locks = 1; | |
23d95a03 | 4058 | for (i = 0; i < CHAINHASH_SIZE; i++) |
a63f38cc | 4059 | INIT_HLIST_HEAD(chainhash_table + i); |
fbb9ce95 IM |
4060 | raw_local_irq_restore(flags); |
4061 | } | |
4062 | ||
4063 | static void zap_class(struct lock_class *class) | |
4064 | { | |
4065 | int i; | |
4066 | ||
4067 | /* | |
4068 | * Remove all dependencies this lock is | |
4069 | * involved in: | |
4070 | */ | |
4071 | for (i = 0; i < nr_list_entries; i++) { | |
4072 | if (list_entries[i].class == class) | |
4073 | list_del_rcu(&list_entries[i].entry); | |
4074 | } | |
4075 | /* | |
4076 | * Unhash the class and remove it from the all_lock_classes list: | |
4077 | */ | |
a63f38cc | 4078 | hlist_del_rcu(&class->hash_entry); |
fbb9ce95 IM |
4079 | list_del_rcu(&class->lock_entry); |
4080 | ||
cee34d88 PZ |
4081 | RCU_INIT_POINTER(class->key, NULL); |
4082 | RCU_INIT_POINTER(class->name, NULL); | |
fbb9ce95 IM |
4083 | } |
4084 | ||
fabe874a | 4085 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
4086 | { |
4087 | return addr >= start && addr < start + size; | |
4088 | } | |
4089 | ||
35a9393c PZ |
4090 | /* |
4091 | * Used in module.c to remove lock classes from memory that is going to be | |
4092 | * freed; and possibly re-used by other modules. | |
4093 | * | |
4094 | * We will have had one sync_sched() before getting here, so we're guaranteed | |
4095 | * nobody will look up these exact classes -- they're properly dead but still | |
4096 | * allocated. | |
4097 | */ | |
fbb9ce95 IM |
4098 | void lockdep_free_key_range(void *start, unsigned long size) |
4099 | { | |
35a9393c | 4100 | struct lock_class *class; |
a63f38cc | 4101 | struct hlist_head *head; |
fbb9ce95 IM |
4102 | unsigned long flags; |
4103 | int i; | |
5a26db5b | 4104 | int locked; |
fbb9ce95 IM |
4105 | |
4106 | raw_local_irq_save(flags); | |
5a26db5b | 4107 | locked = graph_lock(); |
fbb9ce95 IM |
4108 | |
4109 | /* | |
4110 | * Unhash all classes that were created by this module: | |
4111 | */ | |
4112 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
4113 | head = classhash_table + i; | |
a63f38cc | 4114 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
fbb9ce95 IM |
4115 | if (within(class->key, start, size)) |
4116 | zap_class(class); | |
fabe874a AV |
4117 | else if (within(class->name, start, size)) |
4118 | zap_class(class); | |
4119 | } | |
fbb9ce95 IM |
4120 | } |
4121 | ||
5a26db5b NP |
4122 | if (locked) |
4123 | graph_unlock(); | |
fbb9ce95 | 4124 | raw_local_irq_restore(flags); |
35a9393c PZ |
4125 | |
4126 | /* | |
4127 | * Wait for any possible iterators from look_up_lock_class() to pass | |
4128 | * before continuing to free the memory they refer to. | |
4129 | * | |
4130 | * sync_sched() is sufficient because the read-side is IRQ disable. | |
4131 | */ | |
4132 | synchronize_sched(); | |
4133 | ||
4134 | /* | |
4135 | * XXX at this point we could return the resources to the pool; | |
4136 | * instead we leak them. We would need to change to bitmap allocators | |
4137 | * instead of the linear allocators we have now. | |
4138 | */ | |
fbb9ce95 IM |
4139 | } |
4140 | ||
4141 | void lockdep_reset_lock(struct lockdep_map *lock) | |
4142 | { | |
35a9393c | 4143 | struct lock_class *class; |
a63f38cc | 4144 | struct hlist_head *head; |
fbb9ce95 IM |
4145 | unsigned long flags; |
4146 | int i, j; | |
5a26db5b | 4147 | int locked; |
fbb9ce95 IM |
4148 | |
4149 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
4150 | |
4151 | /* | |
d6d897ce IM |
4152 | * Remove all classes this lock might have: |
4153 | */ | |
4154 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
4155 | /* | |
4156 | * If the class exists we look it up and zap it: | |
4157 | */ | |
4158 | class = look_up_lock_class(lock, j); | |
4159 | if (class) | |
4160 | zap_class(class); | |
4161 | } | |
4162 | /* | |
4163 | * Debug check: in the end all mapped classes should | |
4164 | * be gone. | |
fbb9ce95 | 4165 | */ |
5a26db5b | 4166 | locked = graph_lock(); |
fbb9ce95 IM |
4167 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
4168 | head = classhash_table + i; | |
a63f38cc | 4169 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
62016250 HM |
4170 | int match = 0; |
4171 | ||
4172 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
4173 | match |= class == lock->class_cache[j]; | |
4174 | ||
4175 | if (unlikely(match)) { | |
0119fee4 PZ |
4176 | if (debug_locks_off_graph_unlock()) { |
4177 | /* | |
4178 | * We all just reset everything, how did it match? | |
4179 | */ | |
74c383f1 | 4180 | WARN_ON(1); |
0119fee4 | 4181 | } |
d6d897ce | 4182 | goto out_restore; |
fbb9ce95 IM |
4183 | } |
4184 | } | |
4185 | } | |
5a26db5b NP |
4186 | if (locked) |
4187 | graph_unlock(); | |
d6d897ce IM |
4188 | |
4189 | out_restore: | |
fbb9ce95 IM |
4190 | raw_local_irq_restore(flags); |
4191 | } | |
4192 | ||
fbb9ce95 IM |
4193 | void __init lockdep_info(void) |
4194 | { | |
4195 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
4196 | ||
b0788caf | 4197 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
4198 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
4199 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 4200 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
4201 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
4202 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
4203 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
4204 | ||
4205 | printk(" memory used by lock dependency info: %lu kB\n", | |
4206 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
4207 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
4208 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
4209 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 4210 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 4211 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 4212 | + sizeof(struct circular_queue) |
4dd861d6 | 4213 | #endif |
90629209 | 4214 | ) / 1024 |
4dd861d6 | 4215 | ); |
fbb9ce95 IM |
4216 | |
4217 | printk(" per task-struct memory footprint: %lu bytes\n", | |
4218 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
fbb9ce95 IM |
4219 | } |
4220 | ||
fbb9ce95 IM |
4221 | static void |
4222 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 4223 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
4224 | { |
4225 | if (!debug_locks_off()) | |
4226 | return; | |
4227 | if (debug_locks_silent) | |
4228 | return; | |
4229 | ||
b3fbab05 PM |
4230 | printk("\n"); |
4231 | printk("=========================\n"); | |
4232 | printk("[ BUG: held lock freed! ]\n"); | |
fbdc4b9a | 4233 | print_kernel_ident(); |
b3fbab05 | 4234 | printk("-------------------------\n"); |
fbb9ce95 | 4235 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 4236 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 4237 | print_lock(hlock); |
fbb9ce95 IM |
4238 | lockdep_print_held_locks(curr); |
4239 | ||
4240 | printk("\nstack backtrace:\n"); | |
4241 | dump_stack(); | |
4242 | } | |
4243 | ||
54561783 ON |
4244 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4245 | const void* lock_from, unsigned long lock_len) | |
4246 | { | |
4247 | return lock_from + lock_len <= mem_from || | |
4248 | mem_from + mem_len <= lock_from; | |
4249 | } | |
4250 | ||
fbb9ce95 IM |
4251 | /* |
4252 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4253 | * is destroyed or reinitialized - this code checks whether there is | |
4254 | * any held lock in the memory range of <from> to <to>: | |
4255 | */ | |
4256 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4257 | { | |
fbb9ce95 IM |
4258 | struct task_struct *curr = current; |
4259 | struct held_lock *hlock; | |
4260 | unsigned long flags; | |
4261 | int i; | |
4262 | ||
4263 | if (unlikely(!debug_locks)) | |
4264 | return; | |
4265 | ||
4266 | local_irq_save(flags); | |
4267 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4268 | hlock = curr->held_locks + i; | |
4269 | ||
54561783 ON |
4270 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4271 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4272 | continue; |
4273 | ||
54561783 | 4274 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4275 | break; |
4276 | } | |
4277 | local_irq_restore(flags); | |
4278 | } | |
ed07536e | 4279 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 4280 | |
1b1d2fb4 | 4281 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
4282 | { |
4283 | if (!debug_locks_off()) | |
4284 | return; | |
4285 | if (debug_locks_silent) | |
4286 | return; | |
4287 | ||
b3fbab05 PM |
4288 | printk("\n"); |
4289 | printk("=====================================\n"); | |
1b1d2fb4 CC |
4290 | printk("[ BUG: %s/%d still has locks held! ]\n", |
4291 | current->comm, task_pid_nr(current)); | |
fbdc4b9a | 4292 | print_kernel_ident(); |
b3fbab05 | 4293 | printk("-------------------------------------\n"); |
1b1d2fb4 | 4294 | lockdep_print_held_locks(current); |
fbb9ce95 IM |
4295 | printk("\nstack backtrace:\n"); |
4296 | dump_stack(); | |
4297 | } | |
4298 | ||
1b1d2fb4 | 4299 | void debug_check_no_locks_held(void) |
fbb9ce95 | 4300 | { |
1b1d2fb4 CC |
4301 | if (unlikely(current->lockdep_depth > 0)) |
4302 | print_held_locks_bug(); | |
fbb9ce95 | 4303 | } |
1b1d2fb4 | 4304 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 4305 | |
8dce7a9a | 4306 | #ifdef __KERNEL__ |
fbb9ce95 IM |
4307 | void debug_show_all_locks(void) |
4308 | { | |
4309 | struct task_struct *g, *p; | |
4310 | int count = 10; | |
4311 | int unlock = 1; | |
4312 | ||
9c35dd7f JP |
4313 | if (unlikely(!debug_locks)) { |
4314 | printk("INFO: lockdep is turned off.\n"); | |
4315 | return; | |
4316 | } | |
fbb9ce95 IM |
4317 | printk("\nShowing all locks held in the system:\n"); |
4318 | ||
4319 | /* | |
4320 | * Here we try to get the tasklist_lock as hard as possible, | |
4321 | * if not successful after 2 seconds we ignore it (but keep | |
4322 | * trying). This is to enable a debug printout even if a | |
4323 | * tasklist_lock-holding task deadlocks or crashes. | |
4324 | */ | |
4325 | retry: | |
4326 | if (!read_trylock(&tasklist_lock)) { | |
4327 | if (count == 10) | |
4328 | printk("hm, tasklist_lock locked, retrying... "); | |
4329 | if (count) { | |
4330 | count--; | |
4331 | printk(" #%d", 10-count); | |
4332 | mdelay(200); | |
4333 | goto retry; | |
4334 | } | |
4335 | printk(" ignoring it.\n"); | |
4336 | unlock = 0; | |
46fec7ac | 4337 | } else { |
4338 | if (count != 10) | |
4339 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 4340 | } |
fbb9ce95 IM |
4341 | |
4342 | do_each_thread(g, p) { | |
85684873 IM |
4343 | /* |
4344 | * It's not reliable to print a task's held locks | |
4345 | * if it's not sleeping (or if it's not the current | |
4346 | * task): | |
4347 | */ | |
4348 | if (p->state == TASK_RUNNING && p != current) | |
4349 | continue; | |
fbb9ce95 IM |
4350 | if (p->lockdep_depth) |
4351 | lockdep_print_held_locks(p); | |
4352 | if (!unlock) | |
4353 | if (read_trylock(&tasklist_lock)) | |
4354 | unlock = 1; | |
4355 | } while_each_thread(g, p); | |
4356 | ||
4357 | printk("\n"); | |
4358 | printk("=============================================\n\n"); | |
4359 | ||
4360 | if (unlock) | |
4361 | read_unlock(&tasklist_lock); | |
4362 | } | |
fbb9ce95 | 4363 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 4364 | #endif |
fbb9ce95 | 4365 | |
82a1fcb9 IM |
4366 | /* |
4367 | * Careful: only use this function if you are sure that | |
4368 | * the task cannot run in parallel! | |
4369 | */ | |
f1b499f0 | 4370 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4371 | { |
9c35dd7f JP |
4372 | if (unlikely(!debug_locks)) { |
4373 | printk("INFO: lockdep is turned off.\n"); | |
4374 | return; | |
4375 | } | |
fbb9ce95 IM |
4376 | lockdep_print_held_locks(task); |
4377 | } | |
fbb9ce95 | 4378 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 4379 | |
722a9f92 | 4380 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
4381 | { |
4382 | struct task_struct *curr = current; | |
4383 | ||
4384 | if (unlikely(curr->lockdep_depth)) { | |
4385 | if (!debug_locks_off()) | |
4386 | return; | |
b3fbab05 PM |
4387 | printk("\n"); |
4388 | printk("================================================\n"); | |
4389 | printk("[ BUG: lock held when returning to user space! ]\n"); | |
fbdc4b9a | 4390 | print_kernel_ident(); |
b3fbab05 | 4391 | printk("------------------------------------------------\n"); |
b351d164 PZ |
4392 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4393 | curr->comm, curr->pid); | |
4394 | lockdep_print_held_locks(curr); | |
4395 | } | |
4396 | } | |
0632eb3d | 4397 | |
b3fbab05 | 4398 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4399 | { |
4400 | struct task_struct *curr = current; | |
4401 | ||
2b3fc35f | 4402 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4403 | if (!debug_locks_off()) |
4404 | return; | |
2b3fc35f LJ |
4405 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4406 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 PM |
4407 | printk("\n"); |
4408 | printk("===============================\n"); | |
4409 | printk("[ INFO: suspicious RCU usage. ]\n"); | |
fbdc4b9a | 4410 | print_kernel_ident(); |
b3fbab05 PM |
4411 | printk("-------------------------------\n"); |
4412 | printk("%s:%d %s!\n", file, line, s); | |
0632eb3d | 4413 | printk("\nother info that might help us debug this:\n\n"); |
c5fdcec9 PM |
4414 | printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n", |
4415 | !rcu_lockdep_current_cpu_online() | |
4416 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 4417 | : !rcu_is_watching() |
c5fdcec9 PM |
4418 | ? "RCU used illegally from idle CPU!\n" |
4419 | : "", | |
4420 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
4421 | |
4422 | /* | |
4423 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
4424 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
4425 | * considers that CPU to be in an "extended quiescent state", | |
4426 | * which means that RCU will be completely ignoring that CPU. | |
4427 | * Therefore, rcu_read_lock() and friends have absolutely no | |
4428 | * effect on a CPU running in that state. In other words, even if | |
4429 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
4430 | * delete data structures out from under it. RCU really has no | |
4431 | * choice here: we need to keep an RCU-free window in idle where | |
4432 | * the CPU may possibly enter into low power mode. This way we can | |
4433 | * notice an extended quiescent state to other CPUs that started a grace | |
4434 | * period. Otherwise we would delay any grace period as long as we run | |
4435 | * in the idle task. | |
4436 | * | |
4437 | * So complain bitterly if someone does call rcu_read_lock(), | |
4438 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
4439 | */ | |
5c173eb8 | 4440 | if (!rcu_is_watching()) |
0464e937 FW |
4441 | printk("RCU used illegally from extended quiescent state!\n"); |
4442 | ||
0632eb3d PM |
4443 | lockdep_print_held_locks(curr); |
4444 | printk("\nstack backtrace:\n"); | |
4445 | dump_stack(); | |
4446 | } | |
b3fbab05 | 4447 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |