]>
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> | |
e6017571 | 31 | #include <linux/sched/clock.h> |
29930025 | 32 | #include <linux/sched/task.h> |
6d7225f0 | 33 | #include <linux/sched/mm.h> |
fbb9ce95 IM |
34 | #include <linux/delay.h> |
35 | #include <linux/module.h> | |
36 | #include <linux/proc_fs.h> | |
37 | #include <linux/seq_file.h> | |
38 | #include <linux/spinlock.h> | |
39 | #include <linux/kallsyms.h> | |
40 | #include <linux/interrupt.h> | |
41 | #include <linux/stacktrace.h> | |
42 | #include <linux/debug_locks.h> | |
43 | #include <linux/irqflags.h> | |
99de055a | 44 | #include <linux/utsname.h> |
4b32d0a4 | 45 | #include <linux/hash.h> |
81d68a96 | 46 | #include <linux/ftrace.h> |
b4b136f4 | 47 | #include <linux/stringify.h> |
d588e461 | 48 | #include <linux/bitops.h> |
5a0e3ad6 | 49 | #include <linux/gfp.h> |
d3d03d4f | 50 | #include <linux/kmemcheck.h> |
e7904a28 | 51 | #include <linux/random.h> |
dfaaf3fa | 52 | #include <linux/jhash.h> |
af012961 | 53 | |
fbb9ce95 IM |
54 | #include <asm/sections.h> |
55 | ||
56 | #include "lockdep_internals.h" | |
57 | ||
a8d154b0 | 58 | #define CREATE_TRACE_POINTS |
67178767 | 59 | #include <trace/events/lock.h> |
a8d154b0 | 60 | |
f20786ff PZ |
61 | #ifdef CONFIG_PROVE_LOCKING |
62 | int prove_locking = 1; | |
63 | module_param(prove_locking, int, 0644); | |
64 | #else | |
65 | #define prove_locking 0 | |
66 | #endif | |
67 | ||
68 | #ifdef CONFIG_LOCK_STAT | |
69 | int lock_stat = 1; | |
70 | module_param(lock_stat, int, 0644); | |
71 | #else | |
72 | #define lock_stat 0 | |
73 | #endif | |
74 | ||
fbb9ce95 | 75 | /* |
74c383f1 IM |
76 | * lockdep_lock: protects the lockdep graph, the hashes and the |
77 | * class/list/hash allocators. | |
fbb9ce95 IM |
78 | * |
79 | * This is one of the rare exceptions where it's justified | |
80 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 81 | * code to recurse back into the lockdep code... |
fbb9ce95 | 82 | */ |
edc35bd7 | 83 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
84 | |
85 | static int graph_lock(void) | |
86 | { | |
0199c4e6 | 87 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
88 | /* |
89 | * Make sure that if another CPU detected a bug while | |
90 | * walking the graph we dont change it (while the other | |
91 | * CPU is busy printing out stuff with the graph lock | |
92 | * dropped already) | |
93 | */ | |
94 | if (!debug_locks) { | |
0199c4e6 | 95 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
96 | return 0; |
97 | } | |
bb065afb SR |
98 | /* prevent any recursions within lockdep from causing deadlocks */ |
99 | current->lockdep_recursion++; | |
74c383f1 IM |
100 | return 1; |
101 | } | |
102 | ||
103 | static inline int graph_unlock(void) | |
104 | { | |
0119fee4 PZ |
105 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
106 | /* | |
107 | * The lockdep graph lock isn't locked while we expect it to | |
108 | * be, we're confused now, bye! | |
109 | */ | |
381a2292 | 110 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 111 | } |
381a2292 | 112 | |
bb065afb | 113 | current->lockdep_recursion--; |
0199c4e6 | 114 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
115 | return 0; |
116 | } | |
117 | ||
118 | /* | |
119 | * Turn lock debugging off and return with 0 if it was off already, | |
120 | * and also release the graph lock: | |
121 | */ | |
122 | static inline int debug_locks_off_graph_unlock(void) | |
123 | { | |
124 | int ret = debug_locks_off(); | |
125 | ||
0199c4e6 | 126 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
127 | |
128 | return ret; | |
129 | } | |
fbb9ce95 | 130 | |
fbb9ce95 | 131 | unsigned long nr_list_entries; |
af012961 | 132 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 133 | |
fbb9ce95 IM |
134 | /* |
135 | * All data structures here are protected by the global debug_lock. | |
136 | * | |
137 | * Mutex key structs only get allocated, once during bootup, and never | |
138 | * get freed - this significantly simplifies the debugging code. | |
139 | */ | |
140 | unsigned long nr_lock_classes; | |
141 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
142 | ||
f82b217e DJ |
143 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
144 | { | |
145 | if (!hlock->class_idx) { | |
0119fee4 PZ |
146 | /* |
147 | * Someone passed in garbage, we give up. | |
148 | */ | |
f82b217e DJ |
149 | DEBUG_LOCKS_WARN_ON(1); |
150 | return NULL; | |
151 | } | |
152 | return lock_classes + hlock->class_idx - 1; | |
153 | } | |
154 | ||
f20786ff | 155 | #ifdef CONFIG_LOCK_STAT |
25528213 | 156 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
f20786ff | 157 | |
3365e779 PZ |
158 | static inline u64 lockstat_clock(void) |
159 | { | |
c676329a | 160 | return local_clock(); |
3365e779 PZ |
161 | } |
162 | ||
c7e78cff | 163 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
164 | { |
165 | int i; | |
166 | ||
c7e78cff PZ |
167 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
168 | if (points[i] == 0) { | |
169 | points[i] = ip; | |
f20786ff PZ |
170 | break; |
171 | } | |
c7e78cff | 172 | if (points[i] == ip) |
f20786ff PZ |
173 | break; |
174 | } | |
175 | ||
176 | return i; | |
177 | } | |
178 | ||
3365e779 | 179 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
180 | { |
181 | if (time > lt->max) | |
182 | lt->max = time; | |
183 | ||
109d71c6 | 184 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
185 | lt->min = time; |
186 | ||
187 | lt->total += time; | |
188 | lt->nr++; | |
189 | } | |
190 | ||
c46261de PZ |
191 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
192 | { | |
109d71c6 FR |
193 | if (!src->nr) |
194 | return; | |
195 | ||
196 | if (src->max > dst->max) | |
197 | dst->max = src->max; | |
198 | ||
199 | if (src->min < dst->min || !dst->nr) | |
200 | dst->min = src->min; | |
201 | ||
c46261de PZ |
202 | dst->total += src->total; |
203 | dst->nr += src->nr; | |
204 | } | |
205 | ||
206 | struct lock_class_stats lock_stats(struct lock_class *class) | |
207 | { | |
208 | struct lock_class_stats stats; | |
209 | int cpu, i; | |
210 | ||
211 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
212 | for_each_possible_cpu(cpu) { | |
213 | struct lock_class_stats *pcs = | |
1871e52c | 214 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
215 | |
216 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
217 | stats.contention_point[i] += pcs->contention_point[i]; | |
218 | ||
c7e78cff PZ |
219 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
220 | stats.contending_point[i] += pcs->contending_point[i]; | |
221 | ||
c46261de PZ |
222 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
223 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
224 | ||
225 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
226 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
227 | |
228 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
229 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
230 | } |
231 | ||
232 | return stats; | |
233 | } | |
234 | ||
235 | void clear_lock_stats(struct lock_class *class) | |
236 | { | |
237 | int cpu; | |
238 | ||
239 | for_each_possible_cpu(cpu) { | |
240 | struct lock_class_stats *cpu_stats = | |
1871e52c | 241 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
242 | |
243 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
244 | } | |
245 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 246 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
247 | } |
248 | ||
f20786ff PZ |
249 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
250 | { | |
1871e52c | 251 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
252 | } |
253 | ||
254 | static void put_lock_stats(struct lock_class_stats *stats) | |
255 | { | |
1871e52c | 256 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
257 | } |
258 | ||
259 | static void lock_release_holdtime(struct held_lock *hlock) | |
260 | { | |
261 | struct lock_class_stats *stats; | |
3365e779 | 262 | u64 holdtime; |
f20786ff PZ |
263 | |
264 | if (!lock_stat) | |
265 | return; | |
266 | ||
3365e779 | 267 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 268 | |
f82b217e | 269 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
270 | if (hlock->read) |
271 | lock_time_inc(&stats->read_holdtime, holdtime); | |
272 | else | |
273 | lock_time_inc(&stats->write_holdtime, holdtime); | |
274 | put_lock_stats(stats); | |
275 | } | |
276 | #else | |
277 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
278 | { | |
279 | } | |
280 | #endif | |
281 | ||
fbb9ce95 IM |
282 | /* |
283 | * We keep a global list of all lock classes. The list only grows, | |
284 | * never shrinks. The list is only accessed with the lockdep | |
285 | * spinlock lock held. | |
286 | */ | |
287 | LIST_HEAD(all_lock_classes); | |
288 | ||
289 | /* | |
290 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
291 | */ | |
292 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
293 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 294 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
295 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
296 | ||
a63f38cc | 297 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
fbb9ce95 | 298 | |
fbb9ce95 IM |
299 | /* |
300 | * We put the lock dependency chains into a hash-table as well, to cache | |
301 | * their existence: | |
302 | */ | |
303 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
304 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 305 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
306 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
307 | ||
a63f38cc | 308 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
fbb9ce95 IM |
309 | |
310 | /* | |
311 | * The hash key of the lock dependency chains is a hash itself too: | |
312 | * it's a hash of all locks taken up to that lock, including that lock. | |
313 | * It's a 64-bit hash, because it's important for the keys to be | |
314 | * unique. | |
315 | */ | |
dfaaf3fa PZ |
316 | static inline u64 iterate_chain_key(u64 key, u32 idx) |
317 | { | |
318 | u32 k0 = key, k1 = key >> 32; | |
319 | ||
320 | __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ | |
321 | ||
322 | return k0 | (u64)k1 << 32; | |
323 | } | |
fbb9ce95 | 324 | |
1d09daa5 | 325 | void lockdep_off(void) |
fbb9ce95 IM |
326 | { |
327 | current->lockdep_recursion++; | |
328 | } | |
fbb9ce95 IM |
329 | EXPORT_SYMBOL(lockdep_off); |
330 | ||
1d09daa5 | 331 | void lockdep_on(void) |
fbb9ce95 IM |
332 | { |
333 | current->lockdep_recursion--; | |
334 | } | |
fbb9ce95 IM |
335 | EXPORT_SYMBOL(lockdep_on); |
336 | ||
fbb9ce95 IM |
337 | /* |
338 | * Debugging switches: | |
339 | */ | |
340 | ||
341 | #define VERBOSE 0 | |
33e94e96 | 342 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
343 | |
344 | #if VERBOSE | |
345 | # define HARDIRQ_VERBOSE 1 | |
346 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 347 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
348 | #else |
349 | # define HARDIRQ_VERBOSE 0 | |
350 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 351 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
352 | #endif |
353 | ||
cf40bd16 | 354 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
355 | /* |
356 | * Quick filtering for interesting events: | |
357 | */ | |
358 | static int class_filter(struct lock_class *class) | |
359 | { | |
f9829cce AK |
360 | #if 0 |
361 | /* Example */ | |
fbb9ce95 | 362 | if (class->name_version == 1 && |
f9829cce | 363 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
364 | return 1; |
365 | if (class->name_version == 1 && | |
f9829cce | 366 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 367 | return 1; |
f9829cce | 368 | #endif |
a6640897 IM |
369 | /* Filter everything else. 1 would be to allow everything else */ |
370 | return 0; | |
fbb9ce95 IM |
371 | } |
372 | #endif | |
373 | ||
374 | static int verbose(struct lock_class *class) | |
375 | { | |
376 | #if VERBOSE | |
377 | return class_filter(class); | |
378 | #endif | |
379 | return 0; | |
380 | } | |
381 | ||
fbb9ce95 IM |
382 | /* |
383 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 384 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
385 | */ |
386 | unsigned long nr_stack_trace_entries; | |
387 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
388 | ||
2c522836 DJ |
389 | static void print_lockdep_off(const char *bug_msg) |
390 | { | |
391 | printk(KERN_DEBUG "%s\n", bug_msg); | |
392 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 393 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 394 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 395 | #endif |
2c522836 DJ |
396 | } |
397 | ||
fbb9ce95 IM |
398 | static int save_trace(struct stack_trace *trace) |
399 | { | |
400 | trace->nr_entries = 0; | |
401 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
402 | trace->entries = stack_trace + nr_stack_trace_entries; | |
403 | ||
5a1b3999 | 404 | trace->skip = 3; |
5a1b3999 | 405 | |
ab1b6f03 | 406 | save_stack_trace(trace); |
fbb9ce95 | 407 | |
4f84f433 PZ |
408 | /* |
409 | * Some daft arches put -1 at the end to indicate its a full trace. | |
410 | * | |
411 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
412 | * complete trace that maxes out the entries provided will be reported | |
413 | * as incomplete, friggin useless </rant> | |
414 | */ | |
ea5b41f9 TL |
415 | if (trace->nr_entries != 0 && |
416 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
417 | trace->nr_entries--; |
418 | ||
fbb9ce95 IM |
419 | trace->max_entries = trace->nr_entries; |
420 | ||
421 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 422 | |
4f84f433 | 423 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
424 | if (!debug_locks_off_graph_unlock()) |
425 | return 0; | |
426 | ||
2c522836 | 427 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
428 | dump_stack(); |
429 | ||
fbb9ce95 IM |
430 | return 0; |
431 | } | |
432 | ||
433 | return 1; | |
434 | } | |
435 | ||
436 | unsigned int nr_hardirq_chains; | |
437 | unsigned int nr_softirq_chains; | |
438 | unsigned int nr_process_chains; | |
439 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
440 | |
441 | #ifdef CONFIG_DEBUG_LOCKDEP | |
fbb9ce95 IM |
442 | /* |
443 | * Various lockdep statistics: | |
444 | */ | |
bd6d29c2 | 445 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
446 | #endif |
447 | ||
448 | /* | |
449 | * Locking printouts: | |
450 | */ | |
451 | ||
fabe9c42 | 452 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
453 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
454 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
455 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
456 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 457 | |
fbb9ce95 IM |
458 | static const char *usage_str[] = |
459 | { | |
fabe9c42 PZ |
460 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
461 | #include "lockdep_states.h" | |
462 | #undef LOCKDEP_STATE | |
463 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
464 | }; |
465 | ||
466 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
467 | { | |
ffb45122 | 468 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
469 | } |
470 | ||
3ff176ca | 471 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 472 | { |
3ff176ca PZ |
473 | return 1UL << bit; |
474 | } | |
fbb9ce95 | 475 | |
3ff176ca PZ |
476 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
477 | { | |
478 | char c = '.'; | |
479 | ||
480 | if (class->usage_mask & lock_flag(bit + 2)) | |
481 | c = '+'; | |
482 | if (class->usage_mask & lock_flag(bit)) { | |
483 | c = '-'; | |
484 | if (class->usage_mask & lock_flag(bit + 2)) | |
485 | c = '?'; | |
fbb9ce95 IM |
486 | } |
487 | ||
3ff176ca PZ |
488 | return c; |
489 | } | |
cf40bd16 | 490 | |
f510b233 | 491 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 492 | { |
f510b233 | 493 | int i = 0; |
cf40bd16 | 494 | |
f510b233 PZ |
495 | #define LOCKDEP_STATE(__STATE) \ |
496 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
497 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
498 | #include "lockdep_states.h" | |
499 | #undef LOCKDEP_STATE | |
500 | ||
501 | usage[i] = '\0'; | |
fbb9ce95 IM |
502 | } |
503 | ||
e5e78d08 | 504 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
505 | { |
506 | char str[KSYM_NAME_LEN]; | |
507 | const char *name; | |
508 | ||
fbb9ce95 IM |
509 | name = class->name; |
510 | if (!name) { | |
511 | name = __get_key_name(class->key, str); | |
f943fe0f | 512 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 513 | } else { |
f943fe0f | 514 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 515 | if (class->name_version > 1) |
f943fe0f | 516 | printk(KERN_CONT "#%d", class->name_version); |
fbb9ce95 | 517 | if (class->subclass) |
f943fe0f | 518 | printk(KERN_CONT "/%d", class->subclass); |
fbb9ce95 | 519 | } |
e5e78d08 SR |
520 | } |
521 | ||
522 | static void print_lock_name(struct lock_class *class) | |
523 | { | |
524 | char usage[LOCK_USAGE_CHARS]; | |
525 | ||
526 | get_usage_chars(class, usage); | |
527 | ||
f943fe0f | 528 | printk(KERN_CONT " ("); |
e5e78d08 | 529 | __print_lock_name(class); |
f943fe0f | 530 | printk(KERN_CONT "){%s}", usage); |
fbb9ce95 IM |
531 | } |
532 | ||
533 | static void print_lockdep_cache(struct lockdep_map *lock) | |
534 | { | |
535 | const char *name; | |
9281acea | 536 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
537 | |
538 | name = lock->name; | |
539 | if (!name) | |
540 | name = __get_key_name(lock->key->subkeys, str); | |
541 | ||
f943fe0f | 542 | printk(KERN_CONT "%s", name); |
fbb9ce95 IM |
543 | } |
544 | ||
545 | static void print_lock(struct held_lock *hlock) | |
546 | { | |
d7bc3197 PZ |
547 | /* |
548 | * We can be called locklessly through debug_show_all_locks() so be | |
549 | * extra careful, the hlock might have been released and cleared. | |
550 | */ | |
551 | unsigned int class_idx = hlock->class_idx; | |
552 | ||
553 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ | |
554 | barrier(); | |
555 | ||
556 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { | |
f943fe0f | 557 | printk(KERN_CONT "<RELEASED>\n"); |
d7bc3197 PZ |
558 | return; |
559 | } | |
560 | ||
561 | print_lock_name(lock_classes + class_idx - 1); | |
f943fe0f DV |
562 | printk(KERN_CONT ", at: [<%p>] %pS\n", |
563 | (void *)hlock->acquire_ip, (void *)hlock->acquire_ip); | |
fbb9ce95 IM |
564 | } |
565 | ||
566 | static void lockdep_print_held_locks(struct task_struct *curr) | |
567 | { | |
568 | int i, depth = curr->lockdep_depth; | |
569 | ||
570 | if (!depth) { | |
ba25f9dc | 571 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
572 | return; |
573 | } | |
574 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 575 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
576 | |
577 | for (i = 0; i < depth; i++) { | |
578 | printk(" #%d: ", i); | |
579 | print_lock(curr->held_locks + i); | |
580 | } | |
581 | } | |
fbb9ce95 | 582 | |
fbdc4b9a | 583 | static void print_kernel_ident(void) |
8e18257d | 584 | { |
fbdc4b9a | 585 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 586 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
587 | init_utsname()->version, |
588 | print_tainted()); | |
8e18257d PZ |
589 | } |
590 | ||
591 | static int very_verbose(struct lock_class *class) | |
592 | { | |
593 | #if VERY_VERBOSE | |
594 | return class_filter(class); | |
595 | #endif | |
596 | return 0; | |
597 | } | |
598 | ||
fbb9ce95 | 599 | /* |
8e18257d | 600 | * Is this the address of a static object: |
fbb9ce95 | 601 | */ |
8dce7a9a | 602 | #ifdef __KERNEL__ |
8e18257d | 603 | static int static_obj(void *obj) |
fbb9ce95 | 604 | { |
8e18257d PZ |
605 | unsigned long start = (unsigned long) &_stext, |
606 | end = (unsigned long) &_end, | |
607 | addr = (unsigned long) obj; | |
8e18257d | 608 | |
fbb9ce95 | 609 | /* |
8e18257d | 610 | * static variable? |
fbb9ce95 | 611 | */ |
8e18257d PZ |
612 | if ((addr >= start) && (addr < end)) |
613 | return 1; | |
fbb9ce95 | 614 | |
2a9ad18d MF |
615 | if (arch_is_kernel_data(addr)) |
616 | return 1; | |
617 | ||
fbb9ce95 | 618 | /* |
10fad5e4 | 619 | * in-kernel percpu var? |
fbb9ce95 | 620 | */ |
10fad5e4 TH |
621 | if (is_kernel_percpu_address(addr)) |
622 | return 1; | |
fbb9ce95 | 623 | |
8e18257d | 624 | /* |
10fad5e4 | 625 | * module static or percpu var? |
8e18257d | 626 | */ |
10fad5e4 | 627 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 628 | } |
8dce7a9a | 629 | #endif |
99de055a | 630 | |
fbb9ce95 | 631 | /* |
8e18257d PZ |
632 | * To make lock name printouts unique, we calculate a unique |
633 | * class->name_version generation counter: | |
fbb9ce95 | 634 | */ |
8e18257d | 635 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 636 | { |
8e18257d PZ |
637 | struct lock_class *class; |
638 | int count = 0; | |
fbb9ce95 | 639 | |
8e18257d | 640 | if (!new_class->name) |
fbb9ce95 IM |
641 | return 0; |
642 | ||
35a9393c | 643 | list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
644 | if (new_class->key - new_class->subclass == class->key) |
645 | return class->name_version; | |
646 | if (class->name && !strcmp(class->name, new_class->name)) | |
647 | count = max(count, class->name_version); | |
648 | } | |
fbb9ce95 | 649 | |
8e18257d | 650 | return count + 1; |
fbb9ce95 IM |
651 | } |
652 | ||
8e18257d PZ |
653 | /* |
654 | * Register a lock's class in the hash-table, if the class is not present | |
655 | * yet. Otherwise we look it up. We cache the result in the lock object | |
656 | * itself, so actual lookup of the hash should be once per lock object. | |
657 | */ | |
658 | static inline struct lock_class * | |
659 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 660 | { |
8e18257d | 661 | struct lockdep_subclass_key *key; |
a63f38cc | 662 | struct hlist_head *hash_head; |
8e18257d | 663 | struct lock_class *class; |
383776fa | 664 | bool is_static = false; |
fbb9ce95 | 665 | |
4ba053c0 HM |
666 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
667 | debug_locks_off(); | |
668 | printk(KERN_ERR | |
669 | "BUG: looking up invalid subclass: %u\n", subclass); | |
670 | printk(KERN_ERR | |
671 | "turning off the locking correctness validator.\n"); | |
672 | dump_stack(); | |
673 | return NULL; | |
674 | } | |
675 | ||
8e18257d PZ |
676 | /* |
677 | * Static locks do not have their class-keys yet - for them the key | |
383776fa TG |
678 | * is the lock object itself. If the lock is in the per cpu area, |
679 | * the canonical address of the lock (per cpu offset removed) is | |
680 | * used. | |
8e18257d | 681 | */ |
383776fa TG |
682 | if (unlikely(!lock->key)) { |
683 | unsigned long can_addr, addr = (unsigned long)lock; | |
684 | ||
685 | if (__is_kernel_percpu_address(addr, &can_addr)) | |
686 | lock->key = (void *)can_addr; | |
687 | else if (__is_module_percpu_address(addr, &can_addr)) | |
688 | lock->key = (void *)can_addr; | |
689 | else if (static_obj(lock)) | |
690 | lock->key = (void *)lock; | |
691 | else | |
692 | return ERR_PTR(-EINVAL); | |
693 | is_static = true; | |
694 | } | |
fbb9ce95 | 695 | |
8e18257d PZ |
696 | /* |
697 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
698 | * lock_class_key variable is passed in through the mutex_init() | |
699 | * (or spin_lock_init()) call - which acts as the key. For static | |
700 | * locks we use the lock object itself as the key. | |
701 | */ | |
4b32d0a4 PZ |
702 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
703 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 704 | |
8e18257d | 705 | key = lock->key->subkeys + subclass; |
ca268c69 | 706 | |
8e18257d | 707 | hash_head = classhashentry(key); |
74c383f1 | 708 | |
8e18257d | 709 | /* |
35a9393c | 710 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 711 | */ |
35a9393c PZ |
712 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
713 | return NULL; | |
714 | ||
a63f38cc | 715 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
4b32d0a4 | 716 | if (class->key == key) { |
0119fee4 PZ |
717 | /* |
718 | * Huh! same key, different name? Did someone trample | |
719 | * on some memory? We're most confused. | |
720 | */ | |
4b32d0a4 | 721 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 722 | return class; |
4b32d0a4 PZ |
723 | } |
724 | } | |
fbb9ce95 | 725 | |
383776fa | 726 | return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL); |
fbb9ce95 IM |
727 | } |
728 | ||
729 | /* | |
8e18257d PZ |
730 | * Register a lock's class in the hash-table, if the class is not present |
731 | * yet. Otherwise we look it up. We cache the result in the lock object | |
732 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 733 | */ |
c003ed92 | 734 | static struct lock_class * |
8e18257d | 735 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
fbb9ce95 | 736 | { |
8e18257d | 737 | struct lockdep_subclass_key *key; |
a63f38cc | 738 | struct hlist_head *hash_head; |
8e18257d | 739 | struct lock_class *class; |
35a9393c PZ |
740 | |
741 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
742 | |
743 | class = look_up_lock_class(lock, subclass); | |
383776fa | 744 | if (likely(!IS_ERR_OR_NULL(class))) |
87cdee71 | 745 | goto out_set_class_cache; |
8e18257d PZ |
746 | |
747 | /* | |
748 | * Debug-check: all keys must be persistent! | |
383776fa TG |
749 | */ |
750 | if (IS_ERR(class)) { | |
8e18257d PZ |
751 | debug_locks_off(); |
752 | printk("INFO: trying to register non-static key.\n"); | |
753 | printk("the code is fine but needs lockdep annotation.\n"); | |
754 | printk("turning off the locking correctness validator.\n"); | |
755 | dump_stack(); | |
8e18257d PZ |
756 | return NULL; |
757 | } | |
758 | ||
759 | key = lock->key->subkeys + subclass; | |
760 | hash_head = classhashentry(key); | |
761 | ||
8e18257d | 762 | if (!graph_lock()) { |
8e18257d PZ |
763 | return NULL; |
764 | } | |
765 | /* | |
766 | * We have to do the hash-walk again, to avoid races | |
767 | * with another CPU: | |
768 | */ | |
a63f38cc | 769 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
770 | if (class->key == key) |
771 | goto out_unlock_set; | |
35a9393c PZ |
772 | } |
773 | ||
8e18257d PZ |
774 | /* |
775 | * Allocate a new key from the static array, and add it to | |
776 | * the hash: | |
777 | */ | |
778 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
779 | if (!debug_locks_off_graph_unlock()) { | |
8e18257d PZ |
780 | return NULL; |
781 | } | |
8e18257d | 782 | |
2c522836 | 783 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 784 | dump_stack(); |
8e18257d PZ |
785 | return NULL; |
786 | } | |
787 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 788 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
789 | class->key = key; |
790 | class->name = lock->name; | |
791 | class->subclass = subclass; | |
792 | INIT_LIST_HEAD(&class->lock_entry); | |
793 | INIT_LIST_HEAD(&class->locks_before); | |
794 | INIT_LIST_HEAD(&class->locks_after); | |
795 | class->name_version = count_matching_names(class); | |
796 | /* | |
797 | * We use RCU's safe list-add method to make | |
798 | * parallel walking of the hash-list safe: | |
799 | */ | |
a63f38cc | 800 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
1481197b DF |
801 | /* |
802 | * Add it to the global list of classes: | |
803 | */ | |
804 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
805 | |
806 | if (verbose(class)) { | |
807 | graph_unlock(); | |
8e18257d PZ |
808 | |
809 | printk("\nnew class %p: %s", class->key, class->name); | |
810 | if (class->name_version > 1) | |
f943fe0f DV |
811 | printk(KERN_CONT "#%d", class->name_version); |
812 | printk(KERN_CONT "\n"); | |
8e18257d PZ |
813 | dump_stack(); |
814 | ||
8e18257d | 815 | if (!graph_lock()) { |
8e18257d PZ |
816 | return NULL; |
817 | } | |
818 | } | |
819 | out_unlock_set: | |
820 | graph_unlock(); | |
8e18257d | 821 | |
87cdee71 | 822 | out_set_class_cache: |
8e18257d | 823 | if (!subclass || force) |
62016250 HM |
824 | lock->class_cache[0] = class; |
825 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
826 | lock->class_cache[subclass] = class; | |
8e18257d | 827 | |
0119fee4 PZ |
828 | /* |
829 | * Hash collision, did we smoke some? We found a class with a matching | |
830 | * hash but the subclass -- which is hashed in -- didn't match. | |
831 | */ | |
8e18257d PZ |
832 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
833 | return NULL; | |
834 | ||
835 | return class; | |
836 | } | |
837 | ||
838 | #ifdef CONFIG_PROVE_LOCKING | |
839 | /* | |
840 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
841 | * with NULL on failure) | |
842 | */ | |
843 | static struct lock_list *alloc_list_entry(void) | |
844 | { | |
845 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
846 | if (!debug_locks_off_graph_unlock()) | |
847 | return NULL; | |
848 | ||
2c522836 | 849 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 850 | dump_stack(); |
8e18257d PZ |
851 | return NULL; |
852 | } | |
853 | return list_entries + nr_list_entries++; | |
854 | } | |
855 | ||
856 | /* | |
857 | * Add a new dependency to the head of the list: | |
858 | */ | |
83f06168 TE |
859 | static int add_lock_to_list(struct lock_class *this, struct list_head *head, |
860 | unsigned long ip, int distance, | |
861 | struct stack_trace *trace) | |
8e18257d PZ |
862 | { |
863 | struct lock_list *entry; | |
864 | /* | |
865 | * Lock not present yet - get a new dependency struct and | |
866 | * add it to the list: | |
867 | */ | |
868 | entry = alloc_list_entry(); | |
869 | if (!entry) | |
870 | return 0; | |
871 | ||
74870172 ZY |
872 | entry->class = this; |
873 | entry->distance = distance; | |
4726f2a6 | 874 | entry->trace = *trace; |
8e18257d | 875 | /* |
35a9393c PZ |
876 | * Both allocation and removal are done under the graph lock; but |
877 | * iteration is under RCU-sched; see look_up_lock_class() and | |
878 | * lockdep_free_key_range(). | |
8e18257d PZ |
879 | */ |
880 | list_add_tail_rcu(&entry->entry, head); | |
881 | ||
882 | return 1; | |
883 | } | |
884 | ||
98c33edd PZ |
885 | /* |
886 | * For good efficiency of modular, we use power of 2 | |
887 | */ | |
af012961 PZ |
888 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
889 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
890 | ||
98c33edd PZ |
891 | /* |
892 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
893 | * breadth-first search(BFS)algorithem, by which we can build |
894 | * the shortest path from the next lock to be acquired to the | |
895 | * previous held lock if there is a circular between them. | |
98c33edd | 896 | */ |
af012961 PZ |
897 | struct circular_queue { |
898 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
899 | unsigned int front, rear; | |
900 | }; | |
901 | ||
902 | static struct circular_queue lock_cq; | |
af012961 | 903 | |
12f3dfd0 | 904 | unsigned int max_bfs_queue_depth; |
af012961 | 905 | |
e351b660 ML |
906 | static unsigned int lockdep_dependency_gen_id; |
907 | ||
af012961 PZ |
908 | static inline void __cq_init(struct circular_queue *cq) |
909 | { | |
910 | cq->front = cq->rear = 0; | |
e351b660 | 911 | lockdep_dependency_gen_id++; |
af012961 PZ |
912 | } |
913 | ||
914 | static inline int __cq_empty(struct circular_queue *cq) | |
915 | { | |
916 | return (cq->front == cq->rear); | |
917 | } | |
918 | ||
919 | static inline int __cq_full(struct circular_queue *cq) | |
920 | { | |
921 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
922 | } | |
923 | ||
924 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
925 | { | |
926 | if (__cq_full(cq)) | |
927 | return -1; | |
928 | ||
929 | cq->element[cq->rear] = elem; | |
930 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
931 | return 0; | |
932 | } | |
933 | ||
934 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
935 | { | |
936 | if (__cq_empty(cq)) | |
937 | return -1; | |
938 | ||
939 | *elem = cq->element[cq->front]; | |
940 | cq->front = (cq->front + 1) & CQ_MASK; | |
941 | return 0; | |
942 | } | |
943 | ||
944 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
945 | { | |
946 | return (cq->rear - cq->front) & CQ_MASK; | |
947 | } | |
948 | ||
949 | static inline void mark_lock_accessed(struct lock_list *lock, | |
950 | struct lock_list *parent) | |
951 | { | |
952 | unsigned long nr; | |
98c33edd | 953 | |
af012961 | 954 | nr = lock - list_entries; |
0119fee4 | 955 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 956 | lock->parent = parent; |
e351b660 | 957 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
958 | } |
959 | ||
960 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
961 | { | |
962 | unsigned long nr; | |
98c33edd | 963 | |
af012961 | 964 | nr = lock - list_entries; |
0119fee4 | 965 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 966 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
967 | } |
968 | ||
969 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
970 | { | |
971 | return child->parent; | |
972 | } | |
973 | ||
974 | static inline int get_lock_depth(struct lock_list *child) | |
975 | { | |
976 | int depth = 0; | |
977 | struct lock_list *parent; | |
978 | ||
979 | while ((parent = get_lock_parent(child))) { | |
980 | child = parent; | |
981 | depth++; | |
982 | } | |
983 | return depth; | |
984 | } | |
985 | ||
9e2d551e | 986 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
987 | void *data, |
988 | int (*match)(struct lock_list *entry, void *data), | |
989 | struct lock_list **target_entry, | |
990 | int forward) | |
c94aa5ca ML |
991 | { |
992 | struct lock_list *entry; | |
d588e461 | 993 | struct list_head *head; |
c94aa5ca ML |
994 | struct circular_queue *cq = &lock_cq; |
995 | int ret = 1; | |
996 | ||
9e2d551e | 997 | if (match(source_entry, data)) { |
c94aa5ca ML |
998 | *target_entry = source_entry; |
999 | ret = 0; | |
1000 | goto exit; | |
1001 | } | |
1002 | ||
d588e461 ML |
1003 | if (forward) |
1004 | head = &source_entry->class->locks_after; | |
1005 | else | |
1006 | head = &source_entry->class->locks_before; | |
1007 | ||
1008 | if (list_empty(head)) | |
1009 | goto exit; | |
1010 | ||
1011 | __cq_init(cq); | |
c94aa5ca ML |
1012 | __cq_enqueue(cq, (unsigned long)source_entry); |
1013 | ||
1014 | while (!__cq_empty(cq)) { | |
1015 | struct lock_list *lock; | |
c94aa5ca ML |
1016 | |
1017 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1018 | ||
1019 | if (!lock->class) { | |
1020 | ret = -2; | |
1021 | goto exit; | |
1022 | } | |
1023 | ||
1024 | if (forward) | |
1025 | head = &lock->class->locks_after; | |
1026 | else | |
1027 | head = &lock->class->locks_before; | |
1028 | ||
35a9393c PZ |
1029 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1030 | ||
1031 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1032 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1033 | unsigned int cq_depth; |
c94aa5ca | 1034 | mark_lock_accessed(entry, lock); |
9e2d551e | 1035 | if (match(entry, data)) { |
c94aa5ca ML |
1036 | *target_entry = entry; |
1037 | ret = 0; | |
1038 | goto exit; | |
1039 | } | |
1040 | ||
1041 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1042 | ret = -1; | |
1043 | goto exit; | |
1044 | } | |
12f3dfd0 ML |
1045 | cq_depth = __cq_get_elem_count(cq); |
1046 | if (max_bfs_queue_depth < cq_depth) | |
1047 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1048 | } |
1049 | } | |
1050 | } | |
1051 | exit: | |
1052 | return ret; | |
1053 | } | |
1054 | ||
d7aaba14 | 1055 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1056 | void *data, |
1057 | int (*match)(struct lock_list *entry, void *data), | |
1058 | struct lock_list **target_entry) | |
c94aa5ca | 1059 | { |
9e2d551e | 1060 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1061 | |
1062 | } | |
1063 | ||
d7aaba14 | 1064 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1065 | void *data, |
1066 | int (*match)(struct lock_list *entry, void *data), | |
1067 | struct lock_list **target_entry) | |
c94aa5ca | 1068 | { |
9e2d551e | 1069 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1070 | |
1071 | } | |
1072 | ||
8e18257d PZ |
1073 | /* |
1074 | * Recursive, forwards-direction lock-dependency checking, used for | |
1075 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1076 | * checking. | |
8e18257d | 1077 | */ |
8e18257d PZ |
1078 | |
1079 | /* | |
1080 | * Print a dependency chain entry (this is only done when a deadlock | |
1081 | * has been detected): | |
1082 | */ | |
1083 | static noinline int | |
24208ca7 | 1084 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1085 | { |
1086 | if (debug_locks_silent) | |
1087 | return 0; | |
1088 | printk("\n-> #%u", depth); | |
1089 | print_lock_name(target->class); | |
f943fe0f | 1090 | printk(KERN_CONT ":\n"); |
8e18257d PZ |
1091 | print_stack_trace(&target->trace, 6); |
1092 | ||
1093 | return 0; | |
1094 | } | |
1095 | ||
f4185812 SR |
1096 | static void |
1097 | print_circular_lock_scenario(struct held_lock *src, | |
1098 | struct held_lock *tgt, | |
1099 | struct lock_list *prt) | |
1100 | { | |
1101 | struct lock_class *source = hlock_class(src); | |
1102 | struct lock_class *target = hlock_class(tgt); | |
1103 | struct lock_class *parent = prt->class; | |
1104 | ||
1105 | /* | |
1106 | * A direct locking problem where unsafe_class lock is taken | |
1107 | * directly by safe_class lock, then all we need to show | |
1108 | * is the deadlock scenario, as it is obvious that the | |
1109 | * unsafe lock is taken under the safe lock. | |
1110 | * | |
1111 | * But if there is a chain instead, where the safe lock takes | |
1112 | * an intermediate lock (middle_class) where this lock is | |
1113 | * not the same as the safe lock, then the lock chain is | |
1114 | * used to describe the problem. Otherwise we would need | |
1115 | * to show a different CPU case for each link in the chain | |
1116 | * from the safe_class lock to the unsafe_class lock. | |
1117 | */ | |
1118 | if (parent != source) { | |
1119 | printk("Chain exists of:\n "); | |
1120 | __print_lock_name(source); | |
f943fe0f | 1121 | printk(KERN_CONT " --> "); |
f4185812 | 1122 | __print_lock_name(parent); |
f943fe0f | 1123 | printk(KERN_CONT " --> "); |
f4185812 | 1124 | __print_lock_name(target); |
f943fe0f | 1125 | printk(KERN_CONT "\n\n"); |
f4185812 SR |
1126 | } |
1127 | ||
1128 | printk(" Possible unsafe locking scenario:\n\n"); | |
1129 | printk(" CPU0 CPU1\n"); | |
1130 | printk(" ---- ----\n"); | |
1131 | printk(" lock("); | |
1132 | __print_lock_name(target); | |
f943fe0f | 1133 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1134 | printk(" lock("); |
1135 | __print_lock_name(parent); | |
f943fe0f | 1136 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1137 | printk(" lock("); |
1138 | __print_lock_name(target); | |
f943fe0f | 1139 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1140 | printk(" lock("); |
1141 | __print_lock_name(source); | |
f943fe0f | 1142 | printk(KERN_CONT ");\n"); |
f4185812 SR |
1143 | printk("\n *** DEADLOCK ***\n\n"); |
1144 | } | |
1145 | ||
8e18257d PZ |
1146 | /* |
1147 | * When a circular dependency is detected, print the | |
1148 | * header first: | |
1149 | */ | |
1150 | static noinline int | |
db0002a3 ML |
1151 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1152 | struct held_lock *check_src, | |
1153 | struct held_lock *check_tgt) | |
8e18257d PZ |
1154 | { |
1155 | struct task_struct *curr = current; | |
1156 | ||
c94aa5ca | 1157 | if (debug_locks_silent) |
8e18257d PZ |
1158 | return 0; |
1159 | ||
b3fbab05 | 1160 | printk("\n"); |
a5dd63ef PM |
1161 | pr_warn("======================================================\n"); |
1162 | pr_warn("WARNING: possible circular locking dependency detected\n"); | |
fbdc4b9a | 1163 | print_kernel_ident(); |
a5dd63ef | 1164 | pr_warn("------------------------------------------------------\n"); |
8e18257d | 1165 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1166 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1167 | print_lock(check_src); |
8e18257d | 1168 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1169 | print_lock(check_tgt); |
8e18257d PZ |
1170 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1171 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1172 | ||
1173 | print_circular_bug_entry(entry, depth); | |
1174 | ||
1175 | return 0; | |
1176 | } | |
1177 | ||
9e2d551e ML |
1178 | static inline int class_equal(struct lock_list *entry, void *data) |
1179 | { | |
1180 | return entry->class == data; | |
1181 | } | |
1182 | ||
db0002a3 ML |
1183 | static noinline int print_circular_bug(struct lock_list *this, |
1184 | struct lock_list *target, | |
1185 | struct held_lock *check_src, | |
1186 | struct held_lock *check_tgt) | |
8e18257d PZ |
1187 | { |
1188 | struct task_struct *curr = current; | |
c94aa5ca | 1189 | struct lock_list *parent; |
f4185812 | 1190 | struct lock_list *first_parent; |
24208ca7 | 1191 | int depth; |
8e18257d | 1192 | |
c94aa5ca | 1193 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1194 | return 0; |
1195 | ||
db0002a3 | 1196 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1197 | return 0; |
1198 | ||
c94aa5ca ML |
1199 | depth = get_lock_depth(target); |
1200 | ||
db0002a3 | 1201 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1202 | |
1203 | parent = get_lock_parent(target); | |
f4185812 | 1204 | first_parent = parent; |
c94aa5ca ML |
1205 | |
1206 | while (parent) { | |
1207 | print_circular_bug_entry(parent, --depth); | |
1208 | parent = get_lock_parent(parent); | |
1209 | } | |
8e18257d PZ |
1210 | |
1211 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1212 | print_circular_lock_scenario(check_src, check_tgt, |
1213 | first_parent); | |
1214 | ||
8e18257d PZ |
1215 | lockdep_print_held_locks(curr); |
1216 | ||
1217 | printk("\nstack backtrace:\n"); | |
1218 | dump_stack(); | |
1219 | ||
1220 | return 0; | |
1221 | } | |
1222 | ||
db0002a3 ML |
1223 | static noinline int print_bfs_bug(int ret) |
1224 | { | |
1225 | if (!debug_locks_off_graph_unlock()) | |
1226 | return 0; | |
1227 | ||
0119fee4 PZ |
1228 | /* |
1229 | * Breadth-first-search failed, graph got corrupted? | |
1230 | */ | |
db0002a3 ML |
1231 | WARN(1, "lockdep bfs error:%d\n", ret); |
1232 | ||
1233 | return 0; | |
1234 | } | |
1235 | ||
ef681026 | 1236 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1237 | { |
ef681026 ML |
1238 | (*(unsigned long *)data)++; |
1239 | return 0; | |
1240 | } | |
419ca3f1 | 1241 | |
5216d530 | 1242 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1243 | { |
1244 | unsigned long count = 0; | |
1245 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1246 | |
ef681026 | 1247 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1248 | |
ef681026 | 1249 | return count; |
419ca3f1 | 1250 | } |
419ca3f1 DM |
1251 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1252 | { | |
1253 | unsigned long ret, flags; | |
ef681026 ML |
1254 | struct lock_list this; |
1255 | ||
1256 | this.parent = NULL; | |
1257 | this.class = class; | |
419ca3f1 DM |
1258 | |
1259 | local_irq_save(flags); | |
0199c4e6 | 1260 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1261 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1262 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1263 | local_irq_restore(flags); |
1264 | ||
1265 | return ret; | |
1266 | } | |
1267 | ||
5216d530 | 1268 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1269 | { |
ef681026 ML |
1270 | unsigned long count = 0; |
1271 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1272 | |
ef681026 | 1273 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1274 | |
ef681026 | 1275 | return count; |
419ca3f1 DM |
1276 | } |
1277 | ||
1278 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1279 | { | |
1280 | unsigned long ret, flags; | |
ef681026 ML |
1281 | struct lock_list this; |
1282 | ||
1283 | this.parent = NULL; | |
1284 | this.class = class; | |
419ca3f1 DM |
1285 | |
1286 | local_irq_save(flags); | |
0199c4e6 | 1287 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1288 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1289 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1290 | local_irq_restore(flags); |
1291 | ||
1292 | return ret; | |
1293 | } | |
1294 | ||
8e18257d PZ |
1295 | /* |
1296 | * Prove that the dependency graph starting at <entry> can not | |
1297 | * lead to <target>. Print an error and return 0 if it does. | |
1298 | */ | |
1299 | static noinline int | |
db0002a3 ML |
1300 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1301 | struct lock_list **target_entry) | |
8e18257d | 1302 | { |
db0002a3 | 1303 | int result; |
8e18257d | 1304 | |
bd6d29c2 | 1305 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1306 | |
d7aaba14 | 1307 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1308 | |
db0002a3 ML |
1309 | return result; |
1310 | } | |
c94aa5ca | 1311 | |
81d68a96 | 1312 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1313 | /* |
1314 | * Forwards and backwards subgraph searching, for the purposes of | |
1315 | * proving that two subgraphs can be connected by a new dependency | |
1316 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1317 | */ | |
fbb9ce95 | 1318 | |
d7aaba14 ML |
1319 | static inline int usage_match(struct lock_list *entry, void *bit) |
1320 | { | |
1321 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1322 | } | |
1323 | ||
1324 | ||
1325 | ||
fbb9ce95 IM |
1326 | /* |
1327 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1328 | * at @root->class that matches @bit. |
fbb9ce95 | 1329 | * |
d7aaba14 ML |
1330 | * Return 0 if such a node exists in the subgraph, and put that node |
1331 | * into *@target_entry. | |
fbb9ce95 | 1332 | * |
d7aaba14 ML |
1333 | * Return 1 otherwise and keep *@target_entry unchanged. |
1334 | * Return <0 on error. | |
fbb9ce95 | 1335 | */ |
d7aaba14 ML |
1336 | static int |
1337 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1338 | struct lock_list **target_entry) | |
fbb9ce95 | 1339 | { |
d7aaba14 | 1340 | int result; |
fbb9ce95 | 1341 | |
bd6d29c2 | 1342 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1343 | |
d7aaba14 ML |
1344 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1345 | ||
1346 | return result; | |
fbb9ce95 IM |
1347 | } |
1348 | ||
1349 | /* | |
1350 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1351 | * at @root->class that matches @bit. |
fbb9ce95 | 1352 | * |
d7aaba14 ML |
1353 | * Return 0 if such a node exists in the subgraph, and put that node |
1354 | * into *@target_entry. | |
fbb9ce95 | 1355 | * |
d7aaba14 ML |
1356 | * Return 1 otherwise and keep *@target_entry unchanged. |
1357 | * Return <0 on error. | |
fbb9ce95 | 1358 | */ |
d7aaba14 ML |
1359 | static int |
1360 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1361 | struct lock_list **target_entry) | |
fbb9ce95 | 1362 | { |
d7aaba14 | 1363 | int result; |
fbb9ce95 | 1364 | |
bd6d29c2 | 1365 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1366 | |
d7aaba14 | 1367 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1368 | |
d7aaba14 | 1369 | return result; |
fbb9ce95 IM |
1370 | } |
1371 | ||
af012961 PZ |
1372 | static void print_lock_class_header(struct lock_class *class, int depth) |
1373 | { | |
1374 | int bit; | |
1375 | ||
1376 | printk("%*s->", depth, ""); | |
1377 | print_lock_name(class); | |
f943fe0f DV |
1378 | printk(KERN_CONT " ops: %lu", class->ops); |
1379 | printk(KERN_CONT " {\n"); | |
af012961 PZ |
1380 | |
1381 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1382 | if (class->usage_mask & (1 << bit)) { | |
1383 | int len = depth; | |
1384 | ||
1385 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
f943fe0f | 1386 | len += printk(KERN_CONT " at:\n"); |
af012961 PZ |
1387 | print_stack_trace(class->usage_traces + bit, len); |
1388 | } | |
1389 | } | |
1390 | printk("%*s }\n", depth, ""); | |
1391 | ||
f943fe0f DV |
1392 | printk("%*s ... key at: [<%p>] %pS\n", |
1393 | depth, "", class->key, class->key); | |
af012961 PZ |
1394 | } |
1395 | ||
1396 | /* | |
1397 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1398 | */ | |
1399 | static void __used | |
1400 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1401 | struct lock_list *root) | |
1402 | { | |
1403 | struct lock_list *entry = leaf; | |
1404 | int depth; | |
1405 | ||
1406 | /*compute depth from generated tree by BFS*/ | |
1407 | depth = get_lock_depth(leaf); | |
1408 | ||
1409 | do { | |
1410 | print_lock_class_header(entry->class, depth); | |
1411 | printk("%*s ... acquired at:\n", depth, ""); | |
1412 | print_stack_trace(&entry->trace, 2); | |
1413 | printk("\n"); | |
1414 | ||
1415 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1416 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1417 | break; |
1418 | } | |
1419 | ||
1420 | entry = get_lock_parent(entry); | |
1421 | depth--; | |
1422 | } while (entry && (depth >= 0)); | |
1423 | ||
1424 | return; | |
1425 | } | |
d7aaba14 | 1426 | |
3003eba3 SR |
1427 | static void |
1428 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1429 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1430 | struct lock_class *prev_class, |
1431 | struct lock_class *next_class) | |
3003eba3 SR |
1432 | { |
1433 | struct lock_class *safe_class = safe_entry->class; | |
1434 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1435 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1436 | |
1437 | if (middle_class == safe_class) | |
dad3d743 | 1438 | middle_class = next_class; |
3003eba3 SR |
1439 | |
1440 | /* | |
1441 | * A direct locking problem where unsafe_class lock is taken | |
1442 | * directly by safe_class lock, then all we need to show | |
1443 | * is the deadlock scenario, as it is obvious that the | |
1444 | * unsafe lock is taken under the safe lock. | |
1445 | * | |
1446 | * But if there is a chain instead, where the safe lock takes | |
1447 | * an intermediate lock (middle_class) where this lock is | |
1448 | * not the same as the safe lock, then the lock chain is | |
1449 | * used to describe the problem. Otherwise we would need | |
1450 | * to show a different CPU case for each link in the chain | |
1451 | * from the safe_class lock to the unsafe_class lock. | |
1452 | */ | |
1453 | if (middle_class != unsafe_class) { | |
1454 | printk("Chain exists of:\n "); | |
1455 | __print_lock_name(safe_class); | |
f943fe0f | 1456 | printk(KERN_CONT " --> "); |
3003eba3 | 1457 | __print_lock_name(middle_class); |
f943fe0f | 1458 | printk(KERN_CONT " --> "); |
3003eba3 | 1459 | __print_lock_name(unsafe_class); |
f943fe0f | 1460 | printk(KERN_CONT "\n\n"); |
3003eba3 SR |
1461 | } |
1462 | ||
1463 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1464 | printk(" CPU0 CPU1\n"); | |
1465 | printk(" ---- ----\n"); | |
1466 | printk(" lock("); | |
1467 | __print_lock_name(unsafe_class); | |
f943fe0f | 1468 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1469 | printk(" local_irq_disable();\n"); |
1470 | printk(" lock("); | |
1471 | __print_lock_name(safe_class); | |
f943fe0f | 1472 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1473 | printk(" lock("); |
1474 | __print_lock_name(middle_class); | |
f943fe0f | 1475 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1476 | printk(" <Interrupt>\n"); |
1477 | printk(" lock("); | |
1478 | __print_lock_name(safe_class); | |
f943fe0f | 1479 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1480 | printk("\n *** DEADLOCK ***\n\n"); |
1481 | } | |
1482 | ||
fbb9ce95 IM |
1483 | static int |
1484 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1485 | struct lock_list *prev_root, |
1486 | struct lock_list *next_root, | |
1487 | struct lock_list *backwards_entry, | |
1488 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1489 | struct held_lock *prev, |
1490 | struct held_lock *next, | |
1491 | enum lock_usage_bit bit1, | |
1492 | enum lock_usage_bit bit2, | |
1493 | const char *irqclass) | |
1494 | { | |
74c383f1 | 1495 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1496 | return 0; |
1497 | ||
b3fbab05 | 1498 | printk("\n"); |
a5dd63ef PM |
1499 | pr_warn("=====================================================\n"); |
1500 | pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n", | |
fbb9ce95 | 1501 | irqclass, irqclass); |
fbdc4b9a | 1502 | print_kernel_ident(); |
a5dd63ef | 1503 | pr_warn("-----------------------------------------------------\n"); |
fbb9ce95 | 1504 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1505 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1506 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1507 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1508 | curr->hardirqs_enabled, | |
1509 | curr->softirqs_enabled); | |
1510 | print_lock(next); | |
1511 | ||
1512 | printk("\nand this task is already holding:\n"); | |
1513 | print_lock(prev); | |
1514 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1515 | print_lock_name(hlock_class(prev)); |
f943fe0f | 1516 | printk(KERN_CONT " ->"); |
f82b217e | 1517 | print_lock_name(hlock_class(next)); |
f943fe0f | 1518 | printk(KERN_CONT "\n"); |
fbb9ce95 IM |
1519 | |
1520 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1521 | irqclass); | |
24208ca7 | 1522 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1523 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1524 | ||
24208ca7 | 1525 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1526 | |
1527 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1528 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1529 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1530 | printk("..."); | |
1531 | ||
24208ca7 | 1532 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1533 | |
1534 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1535 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1536 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1537 | |
fbb9ce95 IM |
1538 | lockdep_print_held_locks(curr); |
1539 | ||
f943fe0f | 1540 | printk("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass); |
24208ca7 ML |
1541 | if (!save_trace(&prev_root->trace)) |
1542 | return 0; | |
1543 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1544 | |
24208ca7 ML |
1545 | printk("\nthe dependencies between the lock to be acquired"); |
1546 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1547 | if (!save_trace(&next_root->trace)) | |
1548 | return 0; | |
1549 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1550 | |
1551 | printk("\nstack backtrace:\n"); | |
1552 | dump_stack(); | |
1553 | ||
1554 | return 0; | |
1555 | } | |
1556 | ||
1557 | static int | |
1558 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1559 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1560 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1561 | { | |
1562 | int ret; | |
24208ca7 | 1563 | struct lock_list this, that; |
d7aaba14 | 1564 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1565 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1566 | |
1567 | this.parent = NULL; | |
1568 | ||
1569 | this.class = hlock_class(prev); | |
1570 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1571 | if (ret < 0) |
1572 | return print_bfs_bug(ret); | |
1573 | if (ret == 1) | |
1574 | return ret; | |
d7aaba14 | 1575 | |
24208ca7 ML |
1576 | that.parent = NULL; |
1577 | that.class = hlock_class(next); | |
1578 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1579 | if (ret < 0) |
1580 | return print_bfs_bug(ret); | |
1581 | if (ret == 1) | |
1582 | return ret; | |
fbb9ce95 | 1583 | |
24208ca7 ML |
1584 | return print_bad_irq_dependency(curr, &this, &that, |
1585 | target_entry, target_entry1, | |
1586 | prev, next, | |
fbb9ce95 IM |
1587 | bit_backwards, bit_forwards, irqclass); |
1588 | } | |
1589 | ||
4f367d8a PZ |
1590 | static const char *state_names[] = { |
1591 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1592 | __stringify(__STATE), |
4f367d8a PZ |
1593 | #include "lockdep_states.h" |
1594 | #undef LOCKDEP_STATE | |
1595 | }; | |
1596 | ||
1597 | static const char *state_rnames[] = { | |
1598 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1599 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1600 | #include "lockdep_states.h" |
1601 | #undef LOCKDEP_STATE | |
1602 | }; | |
1603 | ||
1604 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1605 | { |
4f367d8a PZ |
1606 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1607 | } | |
8e18257d | 1608 | |
4f367d8a PZ |
1609 | static int exclusive_bit(int new_bit) |
1610 | { | |
8e18257d | 1611 | /* |
4f367d8a PZ |
1612 | * USED_IN |
1613 | * USED_IN_READ | |
1614 | * ENABLED | |
1615 | * ENABLED_READ | |
1616 | * | |
1617 | * bit 0 - write/read | |
1618 | * bit 1 - used_in/enabled | |
1619 | * bit 2+ state | |
8e18257d | 1620 | */ |
4f367d8a PZ |
1621 | |
1622 | int state = new_bit & ~3; | |
1623 | int dir = new_bit & 2; | |
8e18257d PZ |
1624 | |
1625 | /* | |
4f367d8a | 1626 | * keep state, bit flip the direction and strip read. |
8e18257d | 1627 | */ |
4f367d8a PZ |
1628 | return state | (dir ^ 2); |
1629 | } | |
1630 | ||
1631 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1632 | struct held_lock *next, enum lock_usage_bit bit) | |
1633 | { | |
8e18257d | 1634 | /* |
4f367d8a PZ |
1635 | * Prove that the new dependency does not connect a hardirq-safe |
1636 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1637 | * the backwards-subgraph starting at <prev>, and the |
1638 | * forwards-subgraph starting at <next>: | |
1639 | */ | |
4f367d8a PZ |
1640 | if (!check_usage(curr, prev, next, bit, |
1641 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1642 | return 0; |
1643 | ||
4f367d8a PZ |
1644 | bit++; /* _READ */ |
1645 | ||
cf40bd16 | 1646 | /* |
4f367d8a PZ |
1647 | * Prove that the new dependency does not connect a hardirq-safe-read |
1648 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1649 | * the backwards-subgraph starting at <prev>, and the |
1650 | * forwards-subgraph starting at <next>: | |
1651 | */ | |
4f367d8a PZ |
1652 | if (!check_usage(curr, prev, next, bit, |
1653 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1654 | return 0; |
1655 | ||
4f367d8a PZ |
1656 | return 1; |
1657 | } | |
1658 | ||
1659 | static int | |
1660 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1661 | struct held_lock *next) | |
1662 | { | |
1663 | #define LOCKDEP_STATE(__STATE) \ | |
1664 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1665 | return 0; |
4f367d8a PZ |
1666 | #include "lockdep_states.h" |
1667 | #undef LOCKDEP_STATE | |
cf40bd16 | 1668 | |
8e18257d PZ |
1669 | return 1; |
1670 | } | |
1671 | ||
1672 | static void inc_chains(void) | |
1673 | { | |
1674 | if (current->hardirq_context) | |
1675 | nr_hardirq_chains++; | |
1676 | else { | |
1677 | if (current->softirq_context) | |
1678 | nr_softirq_chains++; | |
1679 | else | |
1680 | nr_process_chains++; | |
1681 | } | |
1682 | } | |
1683 | ||
1684 | #else | |
1685 | ||
1686 | static inline int | |
1687 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1688 | struct held_lock *next) | |
1689 | { | |
1690 | return 1; | |
1691 | } | |
1692 | ||
1693 | static inline void inc_chains(void) | |
1694 | { | |
1695 | nr_process_chains++; | |
1696 | } | |
1697 | ||
fbb9ce95 IM |
1698 | #endif |
1699 | ||
48702ecf SR |
1700 | static void |
1701 | print_deadlock_scenario(struct held_lock *nxt, | |
1702 | struct held_lock *prv) | |
1703 | { | |
1704 | struct lock_class *next = hlock_class(nxt); | |
1705 | struct lock_class *prev = hlock_class(prv); | |
1706 | ||
1707 | printk(" Possible unsafe locking scenario:\n\n"); | |
1708 | printk(" CPU0\n"); | |
1709 | printk(" ----\n"); | |
1710 | printk(" lock("); | |
1711 | __print_lock_name(prev); | |
f943fe0f | 1712 | printk(KERN_CONT ");\n"); |
48702ecf SR |
1713 | printk(" lock("); |
1714 | __print_lock_name(next); | |
f943fe0f | 1715 | printk(KERN_CONT ");\n"); |
48702ecf SR |
1716 | printk("\n *** DEADLOCK ***\n\n"); |
1717 | printk(" May be due to missing lock nesting notation\n\n"); | |
1718 | } | |
1719 | ||
fbb9ce95 IM |
1720 | static int |
1721 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1722 | struct held_lock *next) | |
1723 | { | |
74c383f1 | 1724 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1725 | return 0; |
1726 | ||
b3fbab05 | 1727 | printk("\n"); |
a5dd63ef PM |
1728 | pr_warn("============================================\n"); |
1729 | pr_warn("WARNING: possible recursive locking detected\n"); | |
fbdc4b9a | 1730 | print_kernel_ident(); |
a5dd63ef | 1731 | pr_warn("--------------------------------------------\n"); |
fbb9ce95 | 1732 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1733 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1734 | print_lock(next); |
1735 | printk("\nbut task is already holding lock:\n"); | |
1736 | print_lock(prev); | |
1737 | ||
1738 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1739 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1740 | lockdep_print_held_locks(curr); |
1741 | ||
1742 | printk("\nstack backtrace:\n"); | |
1743 | dump_stack(); | |
1744 | ||
1745 | return 0; | |
1746 | } | |
1747 | ||
1748 | /* | |
1749 | * Check whether we are holding such a class already. | |
1750 | * | |
1751 | * (Note that this has to be done separately, because the graph cannot | |
1752 | * detect such classes of deadlocks.) | |
1753 | * | |
1754 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1755 | */ | |
1756 | static int | |
1757 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1758 | struct lockdep_map *next_instance, int read) | |
1759 | { | |
1760 | struct held_lock *prev; | |
7531e2f3 | 1761 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1762 | int i; |
1763 | ||
1764 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1765 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1766 | |
1767 | if (prev->instance == next->nest_lock) | |
1768 | nest = prev; | |
1769 | ||
f82b217e | 1770 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1771 | continue; |
7531e2f3 | 1772 | |
fbb9ce95 IM |
1773 | /* |
1774 | * Allow read-after-read recursion of the same | |
6c9076ec | 1775 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1776 | */ |
6c9076ec | 1777 | if ((read == 2) && prev->read) |
fbb9ce95 | 1778 | return 2; |
7531e2f3 PZ |
1779 | |
1780 | /* | |
1781 | * We're holding the nest_lock, which serializes this lock's | |
1782 | * nesting behaviour. | |
1783 | */ | |
1784 | if (nest) | |
1785 | return 2; | |
1786 | ||
fbb9ce95 IM |
1787 | return print_deadlock_bug(curr, prev, next); |
1788 | } | |
1789 | return 1; | |
1790 | } | |
1791 | ||
1792 | /* | |
1793 | * There was a chain-cache miss, and we are about to add a new dependency | |
1794 | * to a previous lock. We recursively validate the following rules: | |
1795 | * | |
1796 | * - would the adding of the <prev> -> <next> dependency create a | |
1797 | * circular dependency in the graph? [== circular deadlock] | |
1798 | * | |
1799 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1800 | * (in the full backwards-subgraph starting at <prev>) with any | |
1801 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1802 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1803 | * | |
1804 | * - does the new prev->next dependency connect any softirq-safe lock | |
1805 | * (in the full backwards-subgraph starting at <prev>) with any | |
1806 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1807 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1808 | * | |
1809 | * any of these scenarios could lead to a deadlock. | |
1810 | * | |
1811 | * Then if all the validations pass, we add the forwards and backwards | |
1812 | * dependency. | |
1813 | */ | |
1814 | static int | |
1815 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
8a5fd564 | 1816 | struct held_lock *next, int distance, int *stack_saved) |
fbb9ce95 IM |
1817 | { |
1818 | struct lock_list *entry; | |
1819 | int ret; | |
db0002a3 ML |
1820 | struct lock_list this; |
1821 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1822 | /* |
1823 | * Static variable, serialized by the graph_lock(). | |
1824 | * | |
1825 | * We use this static variable to save the stack trace in case | |
1826 | * we call into this function multiple times due to encountering | |
1827 | * trylocks in the held lock stack. | |
1828 | */ | |
1829 | static struct stack_trace trace; | |
fbb9ce95 IM |
1830 | |
1831 | /* | |
1832 | * Prove that the new <prev> -> <next> dependency would not | |
1833 | * create a circular dependency in the graph. (We do this by | |
1834 | * forward-recursing into the graph starting at <next>, and | |
1835 | * checking whether we can reach <prev>.) | |
1836 | * | |
1837 | * We are using global variables to control the recursion, to | |
1838 | * keep the stackframe size of the recursive functions low: | |
1839 | */ | |
db0002a3 ML |
1840 | this.class = hlock_class(next); |
1841 | this.parent = NULL; | |
1842 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1843 | if (unlikely(!ret)) | |
1844 | return print_circular_bug(&this, target_entry, next, prev); | |
1845 | else if (unlikely(ret < 0)) | |
1846 | return print_bfs_bug(ret); | |
c94aa5ca | 1847 | |
8e18257d | 1848 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1849 | return 0; |
1850 | ||
fbb9ce95 IM |
1851 | /* |
1852 | * For recursive read-locks we do all the dependency checks, | |
1853 | * but we dont store read-triggered dependencies (only | |
1854 | * write-triggered dependencies). This ensures that only the | |
1855 | * write-side dependencies matter, and that if for example a | |
1856 | * write-lock never takes any other locks, then the reads are | |
1857 | * equivalent to a NOP. | |
1858 | */ | |
1859 | if (next->read == 2 || prev->read == 2) | |
1860 | return 1; | |
1861 | /* | |
1862 | * Is the <prev> -> <next> dependency already present? | |
1863 | * | |
1864 | * (this may occur even though this is a new chain: consider | |
1865 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1866 | * chains - the second one will be new, but L1 already has | |
1867 | * L2 added to its dependency list, due to the first chain.) | |
1868 | */ | |
f82b217e DJ |
1869 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1870 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1871 | if (distance == 1) |
1872 | entry->distance = 1; | |
fbb9ce95 | 1873 | return 2; |
068135e6 | 1874 | } |
fbb9ce95 IM |
1875 | } |
1876 | ||
8a5fd564 DV |
1877 | if (!*stack_saved) { |
1878 | if (!save_trace(&trace)) | |
1879 | return 0; | |
1880 | *stack_saved = 1; | |
1881 | } | |
4726f2a6 | 1882 | |
fbb9ce95 IM |
1883 | /* |
1884 | * Ok, all validations passed, add the new lock | |
1885 | * to the previous lock's dependency list: | |
1886 | */ | |
83f06168 | 1887 | ret = add_lock_to_list(hlock_class(next), |
f82b217e | 1888 | &hlock_class(prev)->locks_after, |
4726f2a6 | 1889 | next->acquire_ip, distance, &trace); |
068135e6 | 1890 | |
fbb9ce95 IM |
1891 | if (!ret) |
1892 | return 0; | |
910b1b2e | 1893 | |
83f06168 | 1894 | ret = add_lock_to_list(hlock_class(prev), |
f82b217e | 1895 | &hlock_class(next)->locks_before, |
4726f2a6 | 1896 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1897 | if (!ret) |
1898 | return 0; | |
fbb9ce95 IM |
1899 | |
1900 | /* | |
8e18257d PZ |
1901 | * Debugging printouts: |
1902 | */ | |
f82b217e | 1903 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8a5fd564 DV |
1904 | /* We drop graph lock, so another thread can overwrite trace. */ |
1905 | *stack_saved = 0; | |
8e18257d PZ |
1906 | graph_unlock(); |
1907 | printk("\n new dependency: "); | |
f82b217e | 1908 | print_lock_name(hlock_class(prev)); |
f943fe0f | 1909 | printk(KERN_CONT " => "); |
f82b217e | 1910 | print_lock_name(hlock_class(next)); |
f943fe0f | 1911 | printk(KERN_CONT "\n"); |
fbb9ce95 | 1912 | dump_stack(); |
8e18257d | 1913 | return graph_lock(); |
fbb9ce95 | 1914 | } |
8e18257d PZ |
1915 | return 1; |
1916 | } | |
fbb9ce95 | 1917 | |
8e18257d PZ |
1918 | /* |
1919 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1920 | * The ones that are relevant are (in increasing distance from curr): | |
1921 | * all consecutive trylock entries and the final non-trylock entry - or | |
1922 | * the end of this context's lock-chain - whichever comes first. | |
1923 | */ | |
1924 | static int | |
1925 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1926 | { | |
1927 | int depth = curr->lockdep_depth; | |
8a5fd564 | 1928 | int stack_saved = 0; |
8e18257d | 1929 | struct held_lock *hlock; |
d6d897ce | 1930 | |
fbb9ce95 | 1931 | /* |
8e18257d PZ |
1932 | * Debugging checks. |
1933 | * | |
1934 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1935 | */ |
8e18257d PZ |
1936 | if (!depth) |
1937 | goto out_bug; | |
fbb9ce95 | 1938 | /* |
8e18257d PZ |
1939 | * At least two relevant locks must exist for this |
1940 | * to be a head: | |
fbb9ce95 | 1941 | */ |
8e18257d PZ |
1942 | if (curr->held_locks[depth].irq_context != |
1943 | curr->held_locks[depth-1].irq_context) | |
1944 | goto out_bug; | |
74c383f1 | 1945 | |
8e18257d PZ |
1946 | for (;;) { |
1947 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 1948 | hlock = curr->held_locks + depth - 1; |
8e18257d PZ |
1949 | /* |
1950 | * Only non-recursive-read entries get new dependencies | |
1951 | * added: | |
1952 | */ | |
1b5ff816 | 1953 | if (hlock->read != 2 && hlock->check) { |
4726f2a6 | 1954 | if (!check_prev_add(curr, hlock, next, |
8a5fd564 | 1955 | distance, &stack_saved)) |
8e18257d PZ |
1956 | return 0; |
1957 | /* | |
1958 | * Stop after the first non-trylock entry, | |
1959 | * as non-trylock entries have added their | |
1960 | * own direct dependencies already, so this | |
1961 | * lock is connected to them indirectly: | |
1962 | */ | |
1963 | if (!hlock->trylock) | |
1964 | break; | |
74c383f1 | 1965 | } |
8e18257d PZ |
1966 | depth--; |
1967 | /* | |
1968 | * End of lock-stack? | |
1969 | */ | |
1970 | if (!depth) | |
1971 | break; | |
1972 | /* | |
1973 | * Stop the search if we cross into another context: | |
1974 | */ | |
1975 | if (curr->held_locks[depth].irq_context != | |
1976 | curr->held_locks[depth-1].irq_context) | |
1977 | break; | |
fbb9ce95 | 1978 | } |
8e18257d PZ |
1979 | return 1; |
1980 | out_bug: | |
1981 | if (!debug_locks_off_graph_unlock()) | |
1982 | return 0; | |
fbb9ce95 | 1983 | |
0119fee4 PZ |
1984 | /* |
1985 | * Clearly we all shouldn't be here, but since we made it we | |
1986 | * can reliable say we messed up our state. See the above two | |
1987 | * gotos for reasons why we could possibly end up here. | |
1988 | */ | |
8e18257d | 1989 | WARN_ON(1); |
fbb9ce95 | 1990 | |
8e18257d | 1991 | return 0; |
fbb9ce95 IM |
1992 | } |
1993 | ||
8e18257d | 1994 | unsigned long nr_lock_chains; |
443cd507 | 1995 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1996 | int nr_chain_hlocks; |
443cd507 HY |
1997 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1998 | ||
1999 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
2000 | { | |
2001 | return lock_classes + chain_hlocks[chain->base + i]; | |
2002 | } | |
8e18257d | 2003 | |
9e4e7554 IM |
2004 | /* |
2005 | * Returns the index of the first held_lock of the current chain | |
2006 | */ | |
2007 | static inline int get_first_held_lock(struct task_struct *curr, | |
2008 | struct held_lock *hlock) | |
2009 | { | |
2010 | int i; | |
2011 | struct held_lock *hlock_curr; | |
2012 | ||
2013 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2014 | hlock_curr = curr->held_locks + i; | |
2015 | if (hlock_curr->irq_context != hlock->irq_context) | |
2016 | break; | |
2017 | ||
2018 | } | |
2019 | ||
2020 | return ++i; | |
2021 | } | |
2022 | ||
5c8a010c | 2023 | #ifdef CONFIG_DEBUG_LOCKDEP |
39e2e173 AAF |
2024 | /* |
2025 | * Returns the next chain_key iteration | |
2026 | */ | |
2027 | static u64 print_chain_key_iteration(int class_idx, u64 chain_key) | |
2028 | { | |
2029 | u64 new_chain_key = iterate_chain_key(chain_key, class_idx); | |
2030 | ||
2031 | printk(" class_idx:%d -> chain_key:%016Lx", | |
2032 | class_idx, | |
2033 | (unsigned long long)new_chain_key); | |
2034 | return new_chain_key; | |
2035 | } | |
2036 | ||
2037 | static void | |
2038 | print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) | |
2039 | { | |
2040 | struct held_lock *hlock; | |
2041 | u64 chain_key = 0; | |
2042 | int depth = curr->lockdep_depth; | |
2043 | int i; | |
2044 | ||
2045 | printk("depth: %u\n", depth + 1); | |
2046 | for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { | |
2047 | hlock = curr->held_locks + i; | |
2048 | chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); | |
2049 | ||
2050 | print_lock(hlock); | |
2051 | } | |
2052 | ||
2053 | print_chain_key_iteration(hlock_next->class_idx, chain_key); | |
2054 | print_lock(hlock_next); | |
2055 | } | |
2056 | ||
2057 | static void print_chain_keys_chain(struct lock_chain *chain) | |
2058 | { | |
2059 | int i; | |
2060 | u64 chain_key = 0; | |
2061 | int class_id; | |
2062 | ||
2063 | printk("depth: %u\n", chain->depth); | |
2064 | for (i = 0; i < chain->depth; i++) { | |
2065 | class_id = chain_hlocks[chain->base + i]; | |
2066 | chain_key = print_chain_key_iteration(class_id + 1, chain_key); | |
2067 | ||
2068 | print_lock_name(lock_classes + class_id); | |
2069 | printk("\n"); | |
2070 | } | |
2071 | } | |
2072 | ||
2073 | static void print_collision(struct task_struct *curr, | |
2074 | struct held_lock *hlock_next, | |
2075 | struct lock_chain *chain) | |
2076 | { | |
2077 | printk("\n"); | |
a5dd63ef PM |
2078 | pr_warn("============================\n"); |
2079 | pr_warn("WARNING: chain_key collision\n"); | |
39e2e173 | 2080 | print_kernel_ident(); |
a5dd63ef | 2081 | pr_warn("----------------------------\n"); |
39e2e173 AAF |
2082 | printk("%s/%d: ", current->comm, task_pid_nr(current)); |
2083 | printk("Hash chain already cached but the contents don't match!\n"); | |
2084 | ||
2085 | printk("Held locks:"); | |
2086 | print_chain_keys_held_locks(curr, hlock_next); | |
2087 | ||
2088 | printk("Locks in cached chain:"); | |
2089 | print_chain_keys_chain(chain); | |
2090 | ||
2091 | printk("\nstack backtrace:\n"); | |
2092 | dump_stack(); | |
2093 | } | |
5c8a010c | 2094 | #endif |
39e2e173 | 2095 | |
9e4e7554 IM |
2096 | /* |
2097 | * Checks whether the chain and the current held locks are consistent | |
2098 | * in depth and also in content. If they are not it most likely means | |
2099 | * that there was a collision during the calculation of the chain_key. | |
2100 | * Returns: 0 not passed, 1 passed | |
2101 | */ | |
2102 | static int check_no_collision(struct task_struct *curr, | |
2103 | struct held_lock *hlock, | |
2104 | struct lock_chain *chain) | |
2105 | { | |
2106 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2107 | int i, j, id; | |
2108 | ||
2109 | i = get_first_held_lock(curr, hlock); | |
2110 | ||
39e2e173 AAF |
2111 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { |
2112 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2113 | return 0; |
39e2e173 | 2114 | } |
9e4e7554 IM |
2115 | |
2116 | for (j = 0; j < chain->depth - 1; j++, i++) { | |
2117 | id = curr->held_locks[i].class_idx - 1; | |
2118 | ||
39e2e173 AAF |
2119 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { |
2120 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2121 | return 0; |
39e2e173 | 2122 | } |
9e4e7554 IM |
2123 | } |
2124 | #endif | |
2125 | return 1; | |
2126 | } | |
2127 | ||
fbb9ce95 IM |
2128 | /* |
2129 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
2130 | * add it and return 1 - in this case the new dependency chain is |
2131 | * validated. If the key is already hashed, return 0. | |
2132 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 2133 | */ |
443cd507 HY |
2134 | static inline int lookup_chain_cache(struct task_struct *curr, |
2135 | struct held_lock *hlock, | |
2136 | u64 chain_key) | |
fbb9ce95 | 2137 | { |
f82b217e | 2138 | struct lock_class *class = hlock_class(hlock); |
a63f38cc | 2139 | struct hlist_head *hash_head = chainhashentry(chain_key); |
fbb9ce95 | 2140 | struct lock_chain *chain; |
e0944ee6 | 2141 | int i, j; |
fbb9ce95 | 2142 | |
0119fee4 PZ |
2143 | /* |
2144 | * We might need to take the graph lock, ensure we've got IRQs | |
2145 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2146 | * lockdep won't complain about its own locking errors. | |
2147 | */ | |
381a2292 JP |
2148 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2149 | return 0; | |
fbb9ce95 IM |
2150 | /* |
2151 | * We can walk it lock-free, because entries only get added | |
2152 | * to the hash: | |
2153 | */ | |
a63f38cc | 2154 | hlist_for_each_entry_rcu(chain, hash_head, entry) { |
fbb9ce95 IM |
2155 | if (chain->chain_key == chain_key) { |
2156 | cache_hit: | |
bd6d29c2 | 2157 | debug_atomic_inc(chain_lookup_hits); |
9e4e7554 IM |
2158 | if (!check_no_collision(curr, hlock, chain)) |
2159 | return 0; | |
2160 | ||
81fc685a | 2161 | if (very_verbose(class)) |
755cd900 AM |
2162 | printk("\nhash chain already cached, key: " |
2163 | "%016Lx tail class: [%p] %s\n", | |
2164 | (unsigned long long)chain_key, | |
2165 | class->key, class->name); | |
fbb9ce95 IM |
2166 | return 0; |
2167 | } | |
2168 | } | |
81fc685a | 2169 | if (very_verbose(class)) |
755cd900 AM |
2170 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2171 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2172 | /* |
2173 | * Allocate a new chain entry from the static array, and add | |
2174 | * it to the hash: | |
2175 | */ | |
74c383f1 IM |
2176 | if (!graph_lock()) |
2177 | return 0; | |
fbb9ce95 IM |
2178 | /* |
2179 | * We have to walk the chain again locked - to avoid duplicates: | |
2180 | */ | |
a63f38cc | 2181 | hlist_for_each_entry(chain, hash_head, entry) { |
fbb9ce95 | 2182 | if (chain->chain_key == chain_key) { |
74c383f1 | 2183 | graph_unlock(); |
fbb9ce95 IM |
2184 | goto cache_hit; |
2185 | } | |
2186 | } | |
2187 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2188 | if (!debug_locks_off_graph_unlock()) |
2189 | return 0; | |
2190 | ||
2c522836 | 2191 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2192 | dump_stack(); |
fbb9ce95 IM |
2193 | return 0; |
2194 | } | |
2195 | chain = lock_chains + nr_lock_chains++; | |
2196 | chain->chain_key = chain_key; | |
443cd507 | 2197 | chain->irq_context = hlock->irq_context; |
9e4e7554 | 2198 | i = get_first_held_lock(curr, hlock); |
443cd507 | 2199 | chain->depth = curr->lockdep_depth + 1 - i; |
75dd602a PZ |
2200 | |
2201 | BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks)); | |
2202 | BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks)); | |
2203 | BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes)); | |
2204 | ||
e0944ee6 SR |
2205 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2206 | chain->base = nr_chain_hlocks; | |
443cd507 | 2207 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2208 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2209 | chain_hlocks[chain->base + j] = lock_id; |
2210 | } | |
2211 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2212 | } | |
75dd602a PZ |
2213 | |
2214 | if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS) | |
2215 | nr_chain_hlocks += chain->depth; | |
2216 | ||
2217 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2218 | /* | |
2219 | * Important for check_no_collision(). | |
2220 | */ | |
2221 | if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
f9af456a | 2222 | if (!debug_locks_off_graph_unlock()) |
75dd602a PZ |
2223 | return 0; |
2224 | ||
2225 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); | |
2226 | dump_stack(); | |
2227 | return 0; | |
2228 | } | |
2229 | #endif | |
2230 | ||
a63f38cc | 2231 | hlist_add_head_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2232 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2233 | inc_chains(); |
2234 | ||
2235 | return 1; | |
2236 | } | |
2237 | ||
2238 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2239 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2240 | { |
2241 | /* | |
2242 | * Trylock needs to maintain the stack of held locks, but it | |
2243 | * does not add new dependencies, because trylock can be done | |
2244 | * in any order. | |
2245 | * | |
2246 | * We look up the chain_key and do the O(N^2) check and update of | |
2247 | * the dependencies only if this is a new dependency chain. | |
2248 | * (If lookup_chain_cache() returns with 1 it acquires | |
2249 | * graph_lock for us) | |
2250 | */ | |
fb9edbe9 | 2251 | if (!hlock->trylock && hlock->check && |
443cd507 | 2252 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2253 | /* |
2254 | * Check whether last held lock: | |
2255 | * | |
2256 | * - is irq-safe, if this lock is irq-unsafe | |
2257 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2258 | * | |
2259 | * And check whether the new lock's dependency graph | |
2260 | * could lead back to the previous lock. | |
2261 | * | |
2262 | * any of these scenarios could lead to a deadlock. If | |
2263 | * All validations | |
2264 | */ | |
2265 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2266 | ||
2267 | if (!ret) | |
2268 | return 0; | |
2269 | /* | |
2270 | * Mark recursive read, as we jump over it when | |
2271 | * building dependencies (just like we jump over | |
2272 | * trylock entries): | |
2273 | */ | |
2274 | if (ret == 2) | |
2275 | hlock->read = 2; | |
2276 | /* | |
2277 | * Add dependency only if this lock is not the head | |
2278 | * of the chain, and if it's not a secondary read-lock: | |
2279 | */ | |
2280 | if (!chain_head && ret != 2) | |
2281 | if (!check_prevs_add(curr, hlock)) | |
2282 | return 0; | |
2283 | graph_unlock(); | |
2284 | } else | |
2285 | /* after lookup_chain_cache(): */ | |
2286 | if (unlikely(!debug_locks)) | |
2287 | return 0; | |
fbb9ce95 IM |
2288 | |
2289 | return 1; | |
2290 | } | |
8e18257d PZ |
2291 | #else |
2292 | static inline int validate_chain(struct task_struct *curr, | |
2293 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2294 | int chain_head, u64 chain_key) |
8e18257d PZ |
2295 | { |
2296 | return 1; | |
2297 | } | |
ca58abcb | 2298 | #endif |
fbb9ce95 IM |
2299 | |
2300 | /* | |
2301 | * We are building curr_chain_key incrementally, so double-check | |
2302 | * it from scratch, to make sure that it's done correctly: | |
2303 | */ | |
1d09daa5 | 2304 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2305 | { |
2306 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2307 | struct held_lock *hlock, *prev_hlock = NULL; | |
5f18ab5c | 2308 | unsigned int i; |
fbb9ce95 IM |
2309 | u64 chain_key = 0; |
2310 | ||
2311 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2312 | hlock = curr->held_locks + i; | |
2313 | if (chain_key != hlock->prev_chain_key) { | |
2314 | debug_locks_off(); | |
0119fee4 PZ |
2315 | /* |
2316 | * We got mighty confused, our chain keys don't match | |
2317 | * with what we expect, someone trample on our task state? | |
2318 | */ | |
2df8b1d6 | 2319 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2320 | curr->lockdep_depth, i, |
2321 | (unsigned long long)chain_key, | |
2322 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2323 | return; |
2324 | } | |
0119fee4 PZ |
2325 | /* |
2326 | * Whoops ran out of static storage again? | |
2327 | */ | |
5f18ab5c | 2328 | if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) |
381a2292 JP |
2329 | return; |
2330 | ||
fbb9ce95 IM |
2331 | if (prev_hlock && (prev_hlock->irq_context != |
2332 | hlock->irq_context)) | |
2333 | chain_key = 0; | |
5f18ab5c | 2334 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
fbb9ce95 IM |
2335 | prev_hlock = hlock; |
2336 | } | |
2337 | if (chain_key != curr->curr_chain_key) { | |
2338 | debug_locks_off(); | |
0119fee4 PZ |
2339 | /* |
2340 | * More smoking hash instead of calculating it, damn see these | |
2341 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2342 | */ | |
2df8b1d6 | 2343 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2344 | curr->lockdep_depth, i, |
2345 | (unsigned long long)chain_key, | |
2346 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2347 | } |
2348 | #endif | |
2349 | } | |
2350 | ||
282b5c2f SR |
2351 | static void |
2352 | print_usage_bug_scenario(struct held_lock *lock) | |
2353 | { | |
2354 | struct lock_class *class = hlock_class(lock); | |
2355 | ||
2356 | printk(" Possible unsafe locking scenario:\n\n"); | |
2357 | printk(" CPU0\n"); | |
2358 | printk(" ----\n"); | |
2359 | printk(" lock("); | |
2360 | __print_lock_name(class); | |
f943fe0f | 2361 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2362 | printk(" <Interrupt>\n"); |
2363 | printk(" lock("); | |
2364 | __print_lock_name(class); | |
f943fe0f | 2365 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2366 | printk("\n *** DEADLOCK ***\n\n"); |
2367 | } | |
2368 | ||
8e18257d PZ |
2369 | static int |
2370 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2371 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2372 | { | |
2373 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2374 | return 0; | |
2375 | ||
b3fbab05 | 2376 | printk("\n"); |
a5dd63ef PM |
2377 | pr_warn("================================\n"); |
2378 | pr_warn("WARNING: inconsistent lock state\n"); | |
fbdc4b9a | 2379 | print_kernel_ident(); |
a5dd63ef | 2380 | pr_warn("--------------------------------\n"); |
8e18257d PZ |
2381 | |
2382 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2383 | usage_str[prev_bit], usage_str[new_bit]); | |
2384 | ||
2385 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2386 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2387 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2388 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2389 | trace_hardirqs_enabled(curr), | |
2390 | trace_softirqs_enabled(curr)); | |
2391 | print_lock(this); | |
2392 | ||
2393 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2394 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2395 | |
2396 | print_irqtrace_events(curr); | |
2397 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2398 | print_usage_bug_scenario(this); |
2399 | ||
8e18257d PZ |
2400 | lockdep_print_held_locks(curr); |
2401 | ||
2402 | printk("\nstack backtrace:\n"); | |
2403 | dump_stack(); | |
2404 | ||
2405 | return 0; | |
2406 | } | |
2407 | ||
2408 | /* | |
2409 | * Print out an error if an invalid bit is set: | |
2410 | */ | |
2411 | static inline int | |
2412 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2413 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2414 | { | |
f82b217e | 2415 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2416 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2417 | return 1; | |
2418 | } | |
2419 | ||
2420 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2421 | enum lock_usage_bit new_bit); | |
2422 | ||
81d68a96 | 2423 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2424 | |
2425 | /* | |
2426 | * print irq inversion bug: | |
2427 | */ | |
2428 | static int | |
24208ca7 ML |
2429 | print_irq_inversion_bug(struct task_struct *curr, |
2430 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2431 | struct held_lock *this, int forwards, |
2432 | const char *irqclass) | |
2433 | { | |
dad3d743 SR |
2434 | struct lock_list *entry = other; |
2435 | struct lock_list *middle = NULL; | |
2436 | int depth; | |
2437 | ||
74c383f1 | 2438 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2439 | return 0; |
2440 | ||
b3fbab05 | 2441 | printk("\n"); |
a5dd63ef PM |
2442 | pr_warn("========================================================\n"); |
2443 | pr_warn("WARNING: possible irq lock inversion dependency detected\n"); | |
fbdc4b9a | 2444 | print_kernel_ident(); |
a5dd63ef | 2445 | pr_warn("--------------------------------------------------------\n"); |
fbb9ce95 | 2446 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2447 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2448 | print_lock(this); |
2449 | if (forwards) | |
26575e28 | 2450 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2451 | else |
26575e28 | 2452 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2453 | print_lock_name(other->class); |
fbb9ce95 IM |
2454 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2455 | ||
2456 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2457 | |
2458 | /* Find a middle lock (if one exists) */ | |
2459 | depth = get_lock_depth(other); | |
2460 | do { | |
2461 | if (depth == 0 && (entry != root)) { | |
2462 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2463 | break; | |
2464 | } | |
2465 | middle = entry; | |
2466 | entry = get_lock_parent(entry); | |
2467 | depth--; | |
2468 | } while (entry && entry != root && (depth >= 0)); | |
2469 | if (forwards) | |
2470 | print_irq_lock_scenario(root, other, | |
2471 | middle ? middle->class : root->class, other->class); | |
2472 | else | |
2473 | print_irq_lock_scenario(other, root, | |
2474 | middle ? middle->class : other->class, root->class); | |
2475 | ||
fbb9ce95 IM |
2476 | lockdep_print_held_locks(curr); |
2477 | ||
24208ca7 ML |
2478 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2479 | if (!save_trace(&root->trace)) | |
2480 | return 0; | |
2481 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2482 | |
2483 | printk("\nstack backtrace:\n"); | |
2484 | dump_stack(); | |
2485 | ||
2486 | return 0; | |
2487 | } | |
2488 | ||
2489 | /* | |
2490 | * Prove that in the forwards-direction subgraph starting at <this> | |
2491 | * there is no lock matching <mask>: | |
2492 | */ | |
2493 | static int | |
2494 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2495 | enum lock_usage_bit bit, const char *irqclass) | |
2496 | { | |
2497 | int ret; | |
d7aaba14 ML |
2498 | struct lock_list root; |
2499 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2500 | |
d7aaba14 ML |
2501 | root.parent = NULL; |
2502 | root.class = hlock_class(this); | |
2503 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2504 | if (ret < 0) |
2505 | return print_bfs_bug(ret); | |
2506 | if (ret == 1) | |
2507 | return ret; | |
fbb9ce95 | 2508 | |
24208ca7 | 2509 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2510 | this, 1, irqclass); |
fbb9ce95 IM |
2511 | } |
2512 | ||
2513 | /* | |
2514 | * Prove that in the backwards-direction subgraph starting at <this> | |
2515 | * there is no lock matching <mask>: | |
2516 | */ | |
2517 | static int | |
2518 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2519 | enum lock_usage_bit bit, const char *irqclass) | |
2520 | { | |
2521 | int ret; | |
d7aaba14 ML |
2522 | struct lock_list root; |
2523 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2524 | |
d7aaba14 ML |
2525 | root.parent = NULL; |
2526 | root.class = hlock_class(this); | |
2527 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2528 | if (ret < 0) |
2529 | return print_bfs_bug(ret); | |
2530 | if (ret == 1) | |
2531 | return ret; | |
fbb9ce95 | 2532 | |
24208ca7 | 2533 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2534 | this, 0, irqclass); |
fbb9ce95 IM |
2535 | } |
2536 | ||
3117df04 | 2537 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2538 | { |
2539 | printk("irq event stamp: %u\n", curr->irq_events); | |
f943fe0f DV |
2540 | printk("hardirqs last enabled at (%u): [<%p>] %pS\n", |
2541 | curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip, | |
2542 | (void *)curr->hardirq_enable_ip); | |
2543 | printk("hardirqs last disabled at (%u): [<%p>] %pS\n", | |
2544 | curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip, | |
2545 | (void *)curr->hardirq_disable_ip); | |
2546 | printk("softirqs last enabled at (%u): [<%p>] %pS\n", | |
2547 | curr->softirq_enable_event, (void *)curr->softirq_enable_ip, | |
2548 | (void *)curr->softirq_enable_ip); | |
2549 | printk("softirqs last disabled at (%u): [<%p>] %pS\n", | |
2550 | curr->softirq_disable_event, (void *)curr->softirq_disable_ip, | |
2551 | (void *)curr->softirq_disable_ip); | |
fbb9ce95 IM |
2552 | } |
2553 | ||
cd95302d | 2554 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2555 | { |
8e18257d PZ |
2556 | #if HARDIRQ_VERBOSE |
2557 | return class_filter(class); | |
2558 | #endif | |
fbb9ce95 IM |
2559 | return 0; |
2560 | } | |
2561 | ||
cd95302d | 2562 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2563 | { |
8e18257d PZ |
2564 | #if SOFTIRQ_VERBOSE |
2565 | return class_filter(class); | |
2566 | #endif | |
2567 | return 0; | |
fbb9ce95 IM |
2568 | } |
2569 | ||
cd95302d | 2570 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2571 | { |
2572 | #if RECLAIM_VERBOSE | |
2573 | return class_filter(class); | |
2574 | #endif | |
2575 | return 0; | |
2576 | } | |
2577 | ||
fbb9ce95 IM |
2578 | #define STRICT_READ_CHECKS 1 |
2579 | ||
cd95302d PZ |
2580 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2581 | #define LOCKDEP_STATE(__STATE) \ | |
2582 | __STATE##_verbose, | |
2583 | #include "lockdep_states.h" | |
2584 | #undef LOCKDEP_STATE | |
2585 | }; | |
2586 | ||
2587 | static inline int state_verbose(enum lock_usage_bit bit, | |
2588 | struct lock_class *class) | |
2589 | { | |
2590 | return state_verbose_f[bit >> 2](class); | |
2591 | } | |
2592 | ||
42c50d54 PZ |
2593 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2594 | enum lock_usage_bit bit, const char *name); | |
2595 | ||
6a6904d3 | 2596 | static int |
1c21f14e PZ |
2597 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2598 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2599 | { |
f989209e | 2600 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2601 | int read = new_bit & 1; |
42c50d54 PZ |
2602 | int dir = new_bit & 2; |
2603 | ||
38aa2714 PZ |
2604 | /* |
2605 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2606 | * has ENABLED state, which would allow recursion deadlocks. | |
2607 | * | |
2608 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2609 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2610 | */ | |
42c50d54 PZ |
2611 | check_usage_f usage = dir ? |
2612 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2613 | |
38aa2714 PZ |
2614 | /* |
2615 | * Validate that this particular lock does not have conflicting | |
2616 | * usage states. | |
2617 | */ | |
6a6904d3 PZ |
2618 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2619 | return 0; | |
42c50d54 | 2620 | |
38aa2714 PZ |
2621 | /* |
2622 | * Validate that the lock dependencies don't have conflicting usage | |
2623 | * states. | |
2624 | */ | |
2625 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2626 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2627 | return 0; |
780e820b | 2628 | |
38aa2714 PZ |
2629 | /* |
2630 | * Check for read in write conflicts | |
2631 | */ | |
2632 | if (!read) { | |
2633 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2634 | return 0; | |
2635 | ||
2636 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2637 | !usage(curr, this, excl_bit + 1, |
2638 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2639 | return 0; |
2640 | } | |
780e820b | 2641 | |
cd95302d | 2642 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2643 | return 2; |
2644 | ||
2645 | return 1; | |
2646 | } | |
2647 | ||
cf40bd16 | 2648 | enum mark_type { |
36bfb9bb PZ |
2649 | #define LOCKDEP_STATE(__STATE) __STATE, |
2650 | #include "lockdep_states.h" | |
2651 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2652 | }; |
2653 | ||
fbb9ce95 IM |
2654 | /* |
2655 | * Mark all held locks with a usage bit: | |
2656 | */ | |
1d09daa5 | 2657 | static int |
cf40bd16 | 2658 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2659 | { |
2660 | enum lock_usage_bit usage_bit; | |
2661 | struct held_lock *hlock; | |
2662 | int i; | |
2663 | ||
2664 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2665 | hlock = curr->held_locks + i; | |
2666 | ||
cf2ad4d1 PZ |
2667 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2668 | if (hlock->read) | |
2669 | usage_bit += 1; /* READ */ | |
2670 | ||
2671 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2672 | |
34d0ed5e | 2673 | if (!hlock->check) |
efbe2eee PZ |
2674 | continue; |
2675 | ||
4ff773bb | 2676 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2677 | return 0; |
2678 | } | |
2679 | ||
2680 | return 1; | |
2681 | } | |
2682 | ||
fbb9ce95 IM |
2683 | /* |
2684 | * Hardirqs will be enabled: | |
2685 | */ | |
dd4e5d3a | 2686 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2687 | { |
2688 | struct task_struct *curr = current; | |
fbb9ce95 | 2689 | |
fbb9ce95 IM |
2690 | /* we'll do an OFF -> ON transition: */ |
2691 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2692 | |
fbb9ce95 IM |
2693 | /* |
2694 | * We are going to turn hardirqs on, so set the | |
2695 | * usage bit for all held locks: | |
2696 | */ | |
cf40bd16 | 2697 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2698 | return; |
2699 | /* | |
2700 | * If we have softirqs enabled, then set the usage | |
2701 | * bit for all held locks. (disabled hardirqs prevented | |
2702 | * this bit from being set before) | |
2703 | */ | |
2704 | if (curr->softirqs_enabled) | |
cf40bd16 | 2705 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2706 | return; |
2707 | ||
8e18257d PZ |
2708 | curr->hardirq_enable_ip = ip; |
2709 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2710 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2711 | } |
dd4e5d3a | 2712 | |
b35f8305 | 2713 | __visible void trace_hardirqs_on_caller(unsigned long ip) |
dd4e5d3a PZ |
2714 | { |
2715 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2716 | ||
2717 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2718 | return; | |
2719 | ||
7d36b26b PZ |
2720 | if (unlikely(current->hardirqs_enabled)) { |
2721 | /* | |
2722 | * Neither irq nor preemption are disabled here | |
2723 | * so this is racy by nature but losing one hit | |
2724 | * in a stat is not a big deal. | |
2725 | */ | |
2726 | __debug_atomic_inc(redundant_hardirqs_on); | |
2727 | return; | |
2728 | } | |
2729 | ||
0119fee4 PZ |
2730 | /* |
2731 | * We're enabling irqs and according to our state above irqs weren't | |
2732 | * already enabled, yet we find the hardware thinks they are in fact | |
2733 | * enabled.. someone messed up their IRQ state tracing. | |
2734 | */ | |
dd4e5d3a PZ |
2735 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2736 | return; | |
2737 | ||
0119fee4 PZ |
2738 | /* |
2739 | * See the fine text that goes along with this variable definition. | |
2740 | */ | |
7d36b26b PZ |
2741 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2742 | return; | |
2743 | ||
0119fee4 PZ |
2744 | /* |
2745 | * Can't allow enabling interrupts while in an interrupt handler, | |
2746 | * that's general bad form and such. Recursion, limited stack etc.. | |
2747 | */ | |
7d36b26b PZ |
2748 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2749 | return; | |
2750 | ||
dd4e5d3a PZ |
2751 | current->lockdep_recursion = 1; |
2752 | __trace_hardirqs_on_caller(ip); | |
2753 | current->lockdep_recursion = 0; | |
2754 | } | |
81d68a96 | 2755 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2756 | |
1d09daa5 | 2757 | void trace_hardirqs_on(void) |
81d68a96 SR |
2758 | { |
2759 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2760 | } | |
8e18257d PZ |
2761 | EXPORT_SYMBOL(trace_hardirqs_on); |
2762 | ||
2763 | /* | |
2764 | * Hardirqs were disabled: | |
2765 | */ | |
b35f8305 | 2766 | __visible void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2767 | { |
2768 | struct task_struct *curr = current; | |
2769 | ||
6afe40b4 | 2770 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2771 | |
8e18257d PZ |
2772 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2773 | return; | |
2774 | ||
0119fee4 PZ |
2775 | /* |
2776 | * So we're supposed to get called after you mask local IRQs, but for | |
2777 | * some reason the hardware doesn't quite think you did a proper job. | |
2778 | */ | |
8e18257d PZ |
2779 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2780 | return; | |
2781 | ||
2782 | if (curr->hardirqs_enabled) { | |
2783 | /* | |
2784 | * We have done an ON -> OFF transition: | |
2785 | */ | |
2786 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2787 | curr->hardirq_disable_ip = ip; |
8e18257d | 2788 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2789 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2790 | } else |
bd6d29c2 | 2791 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2792 | } |
81d68a96 | 2793 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2794 | |
1d09daa5 | 2795 | void trace_hardirqs_off(void) |
81d68a96 SR |
2796 | { |
2797 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2798 | } | |
8e18257d PZ |
2799 | EXPORT_SYMBOL(trace_hardirqs_off); |
2800 | ||
2801 | /* | |
2802 | * Softirqs will be enabled: | |
2803 | */ | |
2804 | void trace_softirqs_on(unsigned long ip) | |
2805 | { | |
2806 | struct task_struct *curr = current; | |
2807 | ||
dd4e5d3a | 2808 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2809 | return; |
2810 | ||
0119fee4 PZ |
2811 | /* |
2812 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2813 | * funny state and nesting things. | |
2814 | */ | |
8e18257d PZ |
2815 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2816 | return; | |
2817 | ||
2818 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2819 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2820 | return; |
2821 | } | |
2822 | ||
dd4e5d3a | 2823 | current->lockdep_recursion = 1; |
8e18257d PZ |
2824 | /* |
2825 | * We'll do an OFF -> ON transition: | |
2826 | */ | |
2827 | curr->softirqs_enabled = 1; | |
2828 | curr->softirq_enable_ip = ip; | |
2829 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2830 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2831 | /* |
2832 | * We are going to turn softirqs on, so set the | |
2833 | * usage bit for all held locks, if hardirqs are | |
2834 | * enabled too: | |
2835 | */ | |
2836 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2837 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2838 | current->lockdep_recursion = 0; |
8e18257d PZ |
2839 | } |
2840 | ||
2841 | /* | |
2842 | * Softirqs were disabled: | |
2843 | */ | |
2844 | void trace_softirqs_off(unsigned long ip) | |
2845 | { | |
2846 | struct task_struct *curr = current; | |
2847 | ||
dd4e5d3a | 2848 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2849 | return; |
2850 | ||
0119fee4 PZ |
2851 | /* |
2852 | * We fancy IRQs being disabled here, see softirq.c | |
2853 | */ | |
8e18257d PZ |
2854 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2855 | return; | |
2856 | ||
2857 | if (curr->softirqs_enabled) { | |
2858 | /* | |
2859 | * We have done an ON -> OFF transition: | |
2860 | */ | |
2861 | curr->softirqs_enabled = 0; | |
2862 | curr->softirq_disable_ip = ip; | |
2863 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2864 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
2865 | /* |
2866 | * Whoops, we wanted softirqs off, so why aren't they? | |
2867 | */ | |
8e18257d PZ |
2868 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2869 | } else | |
bd6d29c2 | 2870 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2871 | } |
2872 | ||
2f850181 | 2873 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2874 | { |
2875 | struct task_struct *curr = current; | |
2876 | ||
2877 | if (unlikely(!debug_locks)) | |
2878 | return; | |
2879 | ||
7dea19f9 | 2880 | gfp_mask = current_gfp_context(gfp_mask); |
6d7225f0 | 2881 | |
cf40bd16 | 2882 | /* no reclaim without waiting on it */ |
d0164adc | 2883 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) |
cf40bd16 NP |
2884 | return; |
2885 | ||
2886 | /* this guy won't enter reclaim */ | |
2887 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2888 | return; | |
2889 | ||
2890 | /* We're only interested __GFP_FS allocations for now */ | |
7dea19f9 | 2891 | if (!(gfp_mask & __GFP_FS) || (curr->flags & PF_MEMALLOC_NOFS)) |
cf40bd16 NP |
2892 | return; |
2893 | ||
0119fee4 PZ |
2894 | /* |
2895 | * Oi! Can't be having __GFP_FS allocations with IRQs disabled. | |
2896 | */ | |
2f850181 | 2897 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2898 | return; |
2899 | ||
7e784422 MH |
2900 | /* Disable lockdep if explicitly requested */ |
2901 | if (gfp_mask & __GFP_NOLOCKDEP) | |
2902 | return; | |
2903 | ||
cf40bd16 NP |
2904 | mark_held_locks(curr, RECLAIM_FS); |
2905 | } | |
2906 | ||
2f850181 PZ |
2907 | static void check_flags(unsigned long flags); |
2908 | ||
2909 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2910 | { | |
2911 | unsigned long flags; | |
2912 | ||
2913 | if (unlikely(current->lockdep_recursion)) | |
2914 | return; | |
2915 | ||
2916 | raw_local_irq_save(flags); | |
2917 | check_flags(flags); | |
2918 | current->lockdep_recursion = 1; | |
2919 | __lockdep_trace_alloc(gfp_mask, flags); | |
2920 | current->lockdep_recursion = 0; | |
2921 | raw_local_irq_restore(flags); | |
2922 | } | |
2923 | ||
8e18257d PZ |
2924 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2925 | { | |
2926 | /* | |
2927 | * If non-trylock use in a hardirq or softirq context, then | |
2928 | * mark the lock as used in these contexts: | |
2929 | */ | |
2930 | if (!hlock->trylock) { | |
2931 | if (hlock->read) { | |
2932 | if (curr->hardirq_context) | |
2933 | if (!mark_lock(curr, hlock, | |
2934 | LOCK_USED_IN_HARDIRQ_READ)) | |
2935 | return 0; | |
2936 | if (curr->softirq_context) | |
2937 | if (!mark_lock(curr, hlock, | |
2938 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2939 | return 0; | |
2940 | } else { | |
2941 | if (curr->hardirq_context) | |
2942 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2943 | return 0; | |
2944 | if (curr->softirq_context) | |
2945 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2946 | return 0; | |
2947 | } | |
2948 | } | |
2949 | if (!hlock->hardirqs_off) { | |
2950 | if (hlock->read) { | |
2951 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2952 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2953 | return 0; |
2954 | if (curr->softirqs_enabled) | |
2955 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2956 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2957 | return 0; |
2958 | } else { | |
2959 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2960 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2961 | return 0; |
2962 | if (curr->softirqs_enabled) | |
2963 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2964 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2965 | return 0; |
2966 | } | |
2967 | } | |
2968 | ||
cf40bd16 NP |
2969 | /* |
2970 | * We reuse the irq context infrastructure more broadly as a general | |
2971 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2972 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2973 | * allocation). | |
2974 | */ | |
2975 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2976 | if (hlock->read) { | |
2977 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2978 | return 0; | |
2979 | } else { | |
2980 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2981 | return 0; | |
2982 | } | |
2983 | } | |
2984 | ||
8e18257d PZ |
2985 | return 1; |
2986 | } | |
2987 | ||
c2469756 BF |
2988 | static inline unsigned int task_irq_context(struct task_struct *task) |
2989 | { | |
2990 | return 2 * !!task->hardirq_context + !!task->softirq_context; | |
2991 | } | |
2992 | ||
8e18257d PZ |
2993 | static int separate_irq_context(struct task_struct *curr, |
2994 | struct held_lock *hlock) | |
2995 | { | |
2996 | unsigned int depth = curr->lockdep_depth; | |
2997 | ||
2998 | /* | |
2999 | * Keep track of points where we cross into an interrupt context: | |
3000 | */ | |
8e18257d PZ |
3001 | if (depth) { |
3002 | struct held_lock *prev_hlock; | |
3003 | ||
3004 | prev_hlock = curr->held_locks + depth-1; | |
3005 | /* | |
3006 | * If we cross into another context, reset the | |
3007 | * hash key (this also prevents the checking and the | |
3008 | * adding of the dependency to 'prev'): | |
3009 | */ | |
3010 | if (prev_hlock->irq_context != hlock->irq_context) | |
3011 | return 1; | |
3012 | } | |
3013 | return 0; | |
fbb9ce95 IM |
3014 | } |
3015 | ||
0119fee4 | 3016 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 3017 | |
8e18257d PZ |
3018 | static inline |
3019 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
3020 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 3021 | { |
0119fee4 | 3022 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
3023 | return 1; |
3024 | } | |
fbb9ce95 | 3025 | |
8e18257d PZ |
3026 | static inline int mark_irqflags(struct task_struct *curr, |
3027 | struct held_lock *hlock) | |
3028 | { | |
3029 | return 1; | |
3030 | } | |
fbb9ce95 | 3031 | |
c2469756 BF |
3032 | static inline unsigned int task_irq_context(struct task_struct *task) |
3033 | { | |
3034 | return 0; | |
3035 | } | |
3036 | ||
8e18257d PZ |
3037 | static inline int separate_irq_context(struct task_struct *curr, |
3038 | struct held_lock *hlock) | |
3039 | { | |
3040 | return 0; | |
fbb9ce95 IM |
3041 | } |
3042 | ||
868a23a8 PZ |
3043 | void lockdep_trace_alloc(gfp_t gfp_mask) |
3044 | { | |
3045 | } | |
3046 | ||
0119fee4 | 3047 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
3048 | |
3049 | /* | |
8e18257d | 3050 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 3051 | */ |
1d09daa5 | 3052 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 3053 | enum lock_usage_bit new_bit) |
fbb9ce95 | 3054 | { |
8e18257d | 3055 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
3056 | |
3057 | /* | |
8e18257d PZ |
3058 | * If already set then do not dirty the cacheline, |
3059 | * nor do any checks: | |
fbb9ce95 | 3060 | */ |
f82b217e | 3061 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
3062 | return 1; |
3063 | ||
3064 | if (!graph_lock()) | |
3065 | return 0; | |
fbb9ce95 | 3066 | /* |
25985edc | 3067 | * Make sure we didn't race: |
fbb9ce95 | 3068 | */ |
f82b217e | 3069 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
3070 | graph_unlock(); |
3071 | return 1; | |
3072 | } | |
fbb9ce95 | 3073 | |
f82b217e | 3074 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 3075 | |
f82b217e | 3076 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 3077 | return 0; |
fbb9ce95 | 3078 | |
8e18257d | 3079 | switch (new_bit) { |
5346417e PZ |
3080 | #define LOCKDEP_STATE(__STATE) \ |
3081 | case LOCK_USED_IN_##__STATE: \ | |
3082 | case LOCK_USED_IN_##__STATE##_READ: \ | |
3083 | case LOCK_ENABLED_##__STATE: \ | |
3084 | case LOCK_ENABLED_##__STATE##_READ: | |
3085 | #include "lockdep_states.h" | |
3086 | #undef LOCKDEP_STATE | |
8e18257d PZ |
3087 | ret = mark_lock_irq(curr, this, new_bit); |
3088 | if (!ret) | |
3089 | return 0; | |
3090 | break; | |
3091 | case LOCK_USED: | |
bd6d29c2 | 3092 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
3093 | break; |
3094 | default: | |
3095 | if (!debug_locks_off_graph_unlock()) | |
3096 | return 0; | |
3097 | WARN_ON(1); | |
3098 | return 0; | |
3099 | } | |
fbb9ce95 | 3100 | |
8e18257d PZ |
3101 | graph_unlock(); |
3102 | ||
3103 | /* | |
3104 | * We must printk outside of the graph_lock: | |
3105 | */ | |
3106 | if (ret == 2) { | |
3107 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
3108 | print_lock(this); | |
3109 | print_irqtrace_events(curr); | |
3110 | dump_stack(); | |
3111 | } | |
3112 | ||
3113 | return ret; | |
3114 | } | |
fbb9ce95 IM |
3115 | |
3116 | /* | |
3117 | * Initialize a lock instance's lock-class mapping info: | |
3118 | */ | |
3119 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 3120 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 3121 | { |
d3d03d4f YZ |
3122 | int i; |
3123 | ||
3124 | kmemcheck_mark_initialized(lock, sizeof(*lock)); | |
3125 | ||
3126 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) | |
3127 | lock->class_cache[i] = NULL; | |
62016250 | 3128 | |
c8a25005 PZ |
3129 | #ifdef CONFIG_LOCK_STAT |
3130 | lock->cpu = raw_smp_processor_id(); | |
3131 | #endif | |
3132 | ||
0119fee4 PZ |
3133 | /* |
3134 | * Can't be having no nameless bastards around this place! | |
3135 | */ | |
c8a25005 PZ |
3136 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
3137 | lock->name = "NULL"; | |
fbb9ce95 | 3138 | return; |
c8a25005 PZ |
3139 | } |
3140 | ||
3141 | lock->name = name; | |
fbb9ce95 | 3142 | |
0119fee4 PZ |
3143 | /* |
3144 | * No key, no joy, we need to hash something. | |
3145 | */ | |
fbb9ce95 IM |
3146 | if (DEBUG_LOCKS_WARN_ON(!key)) |
3147 | return; | |
fbb9ce95 IM |
3148 | /* |
3149 | * Sanity check, the lock-class key must be persistent: | |
3150 | */ | |
3151 | if (!static_obj(key)) { | |
3152 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
3153 | /* |
3154 | * What it says above ^^^^^, I suggest you read it. | |
3155 | */ | |
fbb9ce95 IM |
3156 | DEBUG_LOCKS_WARN_ON(1); |
3157 | return; | |
3158 | } | |
fbb9ce95 | 3159 | lock->key = key; |
c8a25005 PZ |
3160 | |
3161 | if (unlikely(!debug_locks)) | |
3162 | return; | |
3163 | ||
35a9393c PZ |
3164 | if (subclass) { |
3165 | unsigned long flags; | |
3166 | ||
3167 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3168 | return; | |
3169 | ||
3170 | raw_local_irq_save(flags); | |
3171 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3172 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3173 | current->lockdep_recursion = 0; |
3174 | raw_local_irq_restore(flags); | |
3175 | } | |
fbb9ce95 | 3176 | } |
fbb9ce95 IM |
3177 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3178 | ||
1704f47b | 3179 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3180 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3181 | |
d0945950 ML |
3182 | static int |
3183 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3184 | struct held_lock *hlock, | |
3185 | unsigned long ip) | |
3186 | { | |
3187 | if (!debug_locks_off()) | |
3188 | return 0; | |
3189 | if (debug_locks_silent) | |
3190 | return 0; | |
3191 | ||
3192 | printk("\n"); | |
a5dd63ef PM |
3193 | pr_warn("==================================\n"); |
3194 | pr_warn("WARNING: Nested lock was not taken\n"); | |
d0945950 | 3195 | print_kernel_ident(); |
a5dd63ef | 3196 | pr_warn("----------------------------------\n"); |
d0945950 ML |
3197 | |
3198 | printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); | |
3199 | print_lock(hlock); | |
3200 | ||
3201 | printk("\nbut this task is not holding:\n"); | |
3202 | printk("%s\n", hlock->nest_lock->name); | |
3203 | ||
3204 | printk("\nstack backtrace:\n"); | |
3205 | dump_stack(); | |
3206 | ||
3207 | printk("\nother info that might help us debug this:\n"); | |
3208 | lockdep_print_held_locks(curr); | |
3209 | ||
3210 | printk("\nstack backtrace:\n"); | |
3211 | dump_stack(); | |
3212 | ||
3213 | return 0; | |
3214 | } | |
3215 | ||
f8319483 | 3216 | static int __lock_is_held(struct lockdep_map *lock, int read); |
d0945950 | 3217 | |
fbb9ce95 IM |
3218 | /* |
3219 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3220 | * We maintain the dependency maps and validate the locking attempt: | |
3221 | */ | |
3222 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3223 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3224 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3225 | int references, int pin_count) |
fbb9ce95 IM |
3226 | { |
3227 | struct task_struct *curr = current; | |
d6d897ce | 3228 | struct lock_class *class = NULL; |
fbb9ce95 | 3229 | struct held_lock *hlock; |
5f18ab5c | 3230 | unsigned int depth; |
fbb9ce95 | 3231 | int chain_head = 0; |
bb97a91e | 3232 | int class_idx; |
fbb9ce95 IM |
3233 | u64 chain_key; |
3234 | ||
3235 | if (unlikely(!debug_locks)) | |
3236 | return 0; | |
3237 | ||
0119fee4 PZ |
3238 | /* |
3239 | * Lockdep should run with IRQs disabled, otherwise we could | |
3240 | * get an interrupt which would want to take locks, which would | |
3241 | * end up in lockdep and have you got a head-ache already? | |
3242 | */ | |
fbb9ce95 IM |
3243 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3244 | return 0; | |
3245 | ||
fb9edbe9 ON |
3246 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3247 | check = 0; | |
1704f47b | 3248 | |
62016250 HM |
3249 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3250 | class = lock->class_cache[subclass]; | |
d6d897ce | 3251 | /* |
62016250 | 3252 | * Not cached? |
d6d897ce | 3253 | */ |
fbb9ce95 | 3254 | if (unlikely(!class)) { |
4dfbb9d8 | 3255 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3256 | if (!class) |
3257 | return 0; | |
3258 | } | |
bd6d29c2 | 3259 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3260 | if (very_verbose(class)) { |
3261 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3262 | if (class->name_version > 1) | |
f943fe0f DV |
3263 | printk(KERN_CONT "#%d", class->name_version); |
3264 | printk(KERN_CONT "\n"); | |
fbb9ce95 IM |
3265 | dump_stack(); |
3266 | } | |
3267 | ||
3268 | /* | |
3269 | * Add the lock to the list of currently held locks. | |
3270 | * (we dont increase the depth just yet, up until the | |
3271 | * dependency checks are done) | |
3272 | */ | |
3273 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3274 | /* |
3275 | * Ran out of static storage for our per-task lock stack again have we? | |
3276 | */ | |
fbb9ce95 IM |
3277 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3278 | return 0; | |
3279 | ||
bb97a91e PZ |
3280 | class_idx = class - lock_classes + 1; |
3281 | ||
3282 | if (depth) { | |
3283 | hlock = curr->held_locks + depth - 1; | |
3284 | if (hlock->class_idx == class_idx && nest_lock) { | |
7fb4a2ce PZ |
3285 | if (hlock->references) { |
3286 | /* | |
3287 | * Check: unsigned int references:12, overflow. | |
3288 | */ | |
3289 | if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) | |
3290 | return 0; | |
3291 | ||
bb97a91e | 3292 | hlock->references++; |
7fb4a2ce | 3293 | } else { |
bb97a91e | 3294 | hlock->references = 2; |
7fb4a2ce | 3295 | } |
bb97a91e PZ |
3296 | |
3297 | return 1; | |
3298 | } | |
3299 | } | |
3300 | ||
fbb9ce95 | 3301 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3302 | /* |
3303 | * Plain impossible, we just registered it and checked it weren't no | |
3304 | * NULL like.. I bet this mushroom I ate was good! | |
3305 | */ | |
f82b217e DJ |
3306 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3307 | return 0; | |
bb97a91e | 3308 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3309 | hlock->acquire_ip = ip; |
3310 | hlock->instance = lock; | |
7531e2f3 | 3311 | hlock->nest_lock = nest_lock; |
c2469756 | 3312 | hlock->irq_context = task_irq_context(curr); |
fbb9ce95 IM |
3313 | hlock->trylock = trylock; |
3314 | hlock->read = read; | |
3315 | hlock->check = check; | |
6951b12a | 3316 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3317 | hlock->references = references; |
f20786ff PZ |
3318 | #ifdef CONFIG_LOCK_STAT |
3319 | hlock->waittime_stamp = 0; | |
3365e779 | 3320 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3321 | #endif |
21199f27 | 3322 | hlock->pin_count = pin_count; |
fbb9ce95 | 3323 | |
fb9edbe9 | 3324 | if (check && !mark_irqflags(curr, hlock)) |
8e18257d PZ |
3325 | return 0; |
3326 | ||
fbb9ce95 | 3327 | /* mark it as used: */ |
4ff773bb | 3328 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3329 | return 0; |
8e18257d | 3330 | |
fbb9ce95 | 3331 | /* |
17aacfb9 | 3332 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3333 | * lock keys along the dependency chain. We save the hash value |
3334 | * at every step so that we can get the current hash easily | |
3335 | * after unlock. The chain hash is then used to cache dependency | |
3336 | * results. | |
3337 | * | |
3338 | * The 'key ID' is what is the most compact key value to drive | |
3339 | * the hash, not class->key. | |
3340 | */ | |
0119fee4 PZ |
3341 | /* |
3342 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3343 | */ | |
5f18ab5c | 3344 | if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) |
fbb9ce95 IM |
3345 | return 0; |
3346 | ||
3347 | chain_key = curr->curr_chain_key; | |
3348 | if (!depth) { | |
0119fee4 PZ |
3349 | /* |
3350 | * How can we have a chain hash when we ain't got no keys?! | |
3351 | */ | |
fbb9ce95 IM |
3352 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3353 | return 0; | |
3354 | chain_head = 1; | |
3355 | } | |
3356 | ||
3357 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3358 | if (separate_irq_context(curr, hlock)) { |
3359 | chain_key = 0; | |
3360 | chain_head = 1; | |
fbb9ce95 | 3361 | } |
5f18ab5c | 3362 | chain_key = iterate_chain_key(chain_key, class_idx); |
fbb9ce95 | 3363 | |
f8319483 | 3364 | if (nest_lock && !__lock_is_held(nest_lock, -1)) |
d0945950 ML |
3365 | return print_lock_nested_lock_not_held(curr, hlock, ip); |
3366 | ||
3aa416b0 | 3367 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3368 | return 0; |
381a2292 | 3369 | |
3aa416b0 | 3370 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3371 | curr->lockdep_depth++; |
3372 | check_chain_key(curr); | |
60e114d1 JP |
3373 | #ifdef CONFIG_DEBUG_LOCKDEP |
3374 | if (unlikely(!debug_locks)) | |
3375 | return 0; | |
3376 | #endif | |
fbb9ce95 IM |
3377 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3378 | debug_locks_off(); | |
2c522836 DJ |
3379 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3380 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3381 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3382 | |
3383 | lockdep_print_held_locks(current); | |
3384 | debug_show_all_locks(); | |
eedeeabd | 3385 | dump_stack(); |
c0540606 | 3386 | |
fbb9ce95 IM |
3387 | return 0; |
3388 | } | |
381a2292 | 3389 | |
fbb9ce95 IM |
3390 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3391 | max_lockdep_depth = curr->lockdep_depth; | |
3392 | ||
3393 | return 1; | |
3394 | } | |
3395 | ||
3396 | static int | |
f86f7554 | 3397 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3398 | unsigned long ip) |
3399 | { | |
3400 | if (!debug_locks_off()) | |
3401 | return 0; | |
3402 | if (debug_locks_silent) | |
3403 | return 0; | |
3404 | ||
b3fbab05 | 3405 | printk("\n"); |
a5dd63ef PM |
3406 | pr_warn("=====================================\n"); |
3407 | pr_warn("WARNING: bad unlock balance detected!\n"); | |
fbdc4b9a | 3408 | print_kernel_ident(); |
a5dd63ef | 3409 | pr_warn("-------------------------------------\n"); |
fbb9ce95 | 3410 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3411 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 3412 | print_lockdep_cache(lock); |
f943fe0f | 3413 | printk(KERN_CONT ") at:\n"); |
fbb9ce95 IM |
3414 | print_ip_sym(ip); |
3415 | printk("but there are no more locks to release!\n"); | |
3416 | printk("\nother info that might help us debug this:\n"); | |
3417 | lockdep_print_held_locks(curr); | |
3418 | ||
3419 | printk("\nstack backtrace:\n"); | |
3420 | dump_stack(); | |
3421 | ||
3422 | return 0; | |
3423 | } | |
3424 | ||
bb97a91e PZ |
3425 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3426 | { | |
3427 | if (hlock->instance == lock) | |
3428 | return 1; | |
3429 | ||
3430 | if (hlock->references) { | |
62016250 | 3431 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3432 | |
3433 | if (!class) | |
3434 | class = look_up_lock_class(lock, 0); | |
3435 | ||
80e0401e PZ |
3436 | /* |
3437 | * If look_up_lock_class() failed to find a class, we're trying | |
3438 | * to test if we hold a lock that has never yet been acquired. | |
3439 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3440 | * holding it either, so report failure. | |
3441 | */ | |
383776fa | 3442 | if (IS_ERR_OR_NULL(class)) |
bb97a91e PZ |
3443 | return 0; |
3444 | ||
0119fee4 PZ |
3445 | /* |
3446 | * References, but not a lock we're actually ref-counting? | |
3447 | * State got messed up, follow the sites that change ->references | |
3448 | * and try to make sense of it. | |
3449 | */ | |
bb97a91e PZ |
3450 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3451 | return 0; | |
3452 | ||
3453 | if (hlock->class_idx == class - lock_classes + 1) | |
3454 | return 1; | |
3455 | } | |
3456 | ||
3457 | return 0; | |
3458 | } | |
3459 | ||
41c2c5b8 O |
3460 | /* @depth must not be zero */ |
3461 | static struct held_lock *find_held_lock(struct task_struct *curr, | |
3462 | struct lockdep_map *lock, | |
3463 | unsigned int depth, int *idx) | |
3464 | { | |
3465 | struct held_lock *ret, *hlock, *prev_hlock; | |
3466 | int i; | |
3467 | ||
3468 | i = depth - 1; | |
3469 | hlock = curr->held_locks + i; | |
3470 | ret = hlock; | |
3471 | if (match_held_lock(hlock, lock)) | |
3472 | goto out; | |
3473 | ||
3474 | ret = NULL; | |
3475 | for (i--, prev_hlock = hlock--; | |
3476 | i >= 0; | |
3477 | i--, prev_hlock = hlock--) { | |
3478 | /* | |
3479 | * We must not cross into another context: | |
3480 | */ | |
3481 | if (prev_hlock->irq_context != hlock->irq_context) { | |
3482 | ret = NULL; | |
3483 | break; | |
3484 | } | |
3485 | if (match_held_lock(hlock, lock)) { | |
3486 | ret = hlock; | |
3487 | break; | |
3488 | } | |
3489 | } | |
3490 | ||
3491 | out: | |
3492 | *idx = i; | |
3493 | return ret; | |
3494 | } | |
3495 | ||
e969970b O |
3496 | static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, |
3497 | int idx) | |
3498 | { | |
3499 | struct held_lock *hlock; | |
3500 | ||
3501 | for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) { | |
3502 | if (!__lock_acquire(hlock->instance, | |
3503 | hlock_class(hlock)->subclass, | |
3504 | hlock->trylock, | |
3505 | hlock->read, hlock->check, | |
3506 | hlock->hardirqs_off, | |
3507 | hlock->nest_lock, hlock->acquire_ip, | |
3508 | hlock->references, hlock->pin_count)) | |
3509 | return 1; | |
3510 | } | |
3511 | return 0; | |
3512 | } | |
3513 | ||
64aa348e | 3514 | static int |
00ef9f73 PZ |
3515 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3516 | struct lock_class_key *key, unsigned int subclass, | |
3517 | unsigned long ip) | |
64aa348e PZ |
3518 | { |
3519 | struct task_struct *curr = current; | |
41c2c5b8 | 3520 | struct held_lock *hlock; |
64aa348e PZ |
3521 | struct lock_class *class; |
3522 | unsigned int depth; | |
3523 | int i; | |
3524 | ||
3525 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3526 | /* |
3527 | * This function is about (re)setting the class of a held lock, | |
3528 | * yet we're not actually holding any locks. Naughty user! | |
3529 | */ | |
64aa348e PZ |
3530 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3531 | return 0; | |
3532 | ||
41c2c5b8 O |
3533 | hlock = find_held_lock(curr, lock, depth, &i); |
3534 | if (!hlock) | |
3535 | return print_unlock_imbalance_bug(curr, lock, ip); | |
64aa348e | 3536 | |
00ef9f73 | 3537 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3538 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3539 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3540 | |
3541 | curr->lockdep_depth = i; | |
3542 | curr->curr_chain_key = hlock->prev_chain_key; | |
3543 | ||
e969970b O |
3544 | if (reacquire_held_locks(curr, depth, i)) |
3545 | return 0; | |
64aa348e | 3546 | |
0119fee4 PZ |
3547 | /* |
3548 | * I took it apart and put it back together again, except now I have | |
3549 | * these 'spare' parts.. where shall I put them. | |
3550 | */ | |
64aa348e PZ |
3551 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3552 | return 0; | |
3553 | return 1; | |
3554 | } | |
3555 | ||
6419c4af O |
3556 | static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
3557 | { | |
3558 | struct task_struct *curr = current; | |
3559 | struct held_lock *hlock; | |
3560 | unsigned int depth; | |
3561 | int i; | |
3562 | ||
3563 | depth = curr->lockdep_depth; | |
3564 | /* | |
3565 | * This function is about (re)setting the class of a held lock, | |
3566 | * yet we're not actually holding any locks. Naughty user! | |
3567 | */ | |
3568 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3569 | return 0; | |
3570 | ||
3571 | hlock = find_held_lock(curr, lock, depth, &i); | |
3572 | if (!hlock) | |
3573 | return print_unlock_imbalance_bug(curr, lock, ip); | |
3574 | ||
3575 | curr->lockdep_depth = i; | |
3576 | curr->curr_chain_key = hlock->prev_chain_key; | |
3577 | ||
3578 | WARN(hlock->read, "downgrading a read lock"); | |
3579 | hlock->read = 1; | |
3580 | hlock->acquire_ip = ip; | |
3581 | ||
3582 | if (reacquire_held_locks(curr, depth, i)) | |
3583 | return 0; | |
3584 | ||
3585 | /* | |
3586 | * I took it apart and put it back together again, except now I have | |
3587 | * these 'spare' parts.. where shall I put them. | |
3588 | */ | |
3589 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
3590 | return 0; | |
3591 | return 1; | |
3592 | } | |
3593 | ||
fbb9ce95 | 3594 | /* |
e0f56fd7 PZ |
3595 | * Remove the lock to the list of currently held locks - this gets |
3596 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3597 | * mutex_lock_interruptible()). | |
3598 | * | |
3599 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
3600 | */ |
3601 | static int | |
e0f56fd7 | 3602 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
fbb9ce95 | 3603 | { |
e0f56fd7 | 3604 | struct task_struct *curr = current; |
41c2c5b8 | 3605 | struct held_lock *hlock; |
fbb9ce95 IM |
3606 | unsigned int depth; |
3607 | int i; | |
3608 | ||
e0f56fd7 PZ |
3609 | if (unlikely(!debug_locks)) |
3610 | return 0; | |
3611 | ||
fbb9ce95 | 3612 | depth = curr->lockdep_depth; |
0119fee4 PZ |
3613 | /* |
3614 | * So we're all set to release this lock.. wait what lock? We don't | |
3615 | * own any locks, you've been drinking again? | |
3616 | */ | |
e0f56fd7 PZ |
3617 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
3618 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3619 | |
e0f56fd7 PZ |
3620 | /* |
3621 | * Check whether the lock exists in the current stack | |
3622 | * of held locks: | |
3623 | */ | |
41c2c5b8 O |
3624 | hlock = find_held_lock(curr, lock, depth, &i); |
3625 | if (!hlock) | |
3626 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3627 | |
bb97a91e PZ |
3628 | if (hlock->instance == lock) |
3629 | lock_release_holdtime(hlock); | |
3630 | ||
a24fc60d PZ |
3631 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
3632 | ||
bb97a91e PZ |
3633 | if (hlock->references) { |
3634 | hlock->references--; | |
3635 | if (hlock->references) { | |
3636 | /* | |
3637 | * We had, and after removing one, still have | |
3638 | * references, the current lock stack is still | |
3639 | * valid. We're done! | |
3640 | */ | |
3641 | return 1; | |
3642 | } | |
3643 | } | |
f20786ff | 3644 | |
fbb9ce95 IM |
3645 | /* |
3646 | * We have the right lock to unlock, 'hlock' points to it. | |
3647 | * Now we remove it from the stack, and add back the other | |
3648 | * entries (if any), recalculating the hash along the way: | |
3649 | */ | |
bb97a91e | 3650 | |
fbb9ce95 IM |
3651 | curr->lockdep_depth = i; |
3652 | curr->curr_chain_key = hlock->prev_chain_key; | |
3653 | ||
e969970b O |
3654 | if (reacquire_held_locks(curr, depth, i + 1)) |
3655 | return 0; | |
fbb9ce95 | 3656 | |
0119fee4 PZ |
3657 | /* |
3658 | * We had N bottles of beer on the wall, we drank one, but now | |
3659 | * there's not N-1 bottles of beer left on the wall... | |
3660 | */ | |
fbb9ce95 IM |
3661 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3662 | return 0; | |
f20786ff | 3663 | |
fbb9ce95 IM |
3664 | return 1; |
3665 | } | |
3666 | ||
f8319483 | 3667 | static int __lock_is_held(struct lockdep_map *lock, int read) |
fbb9ce95 | 3668 | { |
f607c668 PZ |
3669 | struct task_struct *curr = current; |
3670 | int i; | |
fbb9ce95 | 3671 | |
f607c668 | 3672 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 3673 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 3674 | |
f8319483 PZ |
3675 | if (match_held_lock(hlock, lock)) { |
3676 | if (read == -1 || hlock->read == read) | |
3677 | return 1; | |
3678 | ||
3679 | return 0; | |
3680 | } | |
f607c668 | 3681 | } |
f20786ff | 3682 | |
f607c668 | 3683 | return 0; |
fbb9ce95 IM |
3684 | } |
3685 | ||
e7904a28 PZ |
3686 | static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) |
3687 | { | |
3688 | struct pin_cookie cookie = NIL_COOKIE; | |
3689 | struct task_struct *curr = current; | |
3690 | int i; | |
3691 | ||
3692 | if (unlikely(!debug_locks)) | |
3693 | return cookie; | |
3694 | ||
3695 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3696 | struct held_lock *hlock = curr->held_locks + i; | |
3697 | ||
3698 | if (match_held_lock(hlock, lock)) { | |
3699 | /* | |
3700 | * Grab 16bits of randomness; this is sufficient to not | |
3701 | * be guessable and still allows some pin nesting in | |
3702 | * our u32 pin_count. | |
3703 | */ | |
3704 | cookie.val = 1 + (prandom_u32() >> 16); | |
3705 | hlock->pin_count += cookie.val; | |
3706 | return cookie; | |
3707 | } | |
3708 | } | |
3709 | ||
3710 | WARN(1, "pinning an unheld lock\n"); | |
3711 | return cookie; | |
3712 | } | |
3713 | ||
3714 | static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
fbb9ce95 IM |
3715 | { |
3716 | struct task_struct *curr = current; | |
a24fc60d | 3717 | int i; |
fbb9ce95 | 3718 | |
a24fc60d | 3719 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
3720 | return; |
3721 | ||
a24fc60d PZ |
3722 | for (i = 0; i < curr->lockdep_depth; i++) { |
3723 | struct held_lock *hlock = curr->held_locks + i; | |
3724 | ||
3725 | if (match_held_lock(hlock, lock)) { | |
e7904a28 | 3726 | hlock->pin_count += cookie.val; |
fbb9ce95 | 3727 | return; |
a24fc60d | 3728 | } |
fbb9ce95 IM |
3729 | } |
3730 | ||
a24fc60d | 3731 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
3732 | } |
3733 | ||
e7904a28 | 3734 | static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
f607c668 PZ |
3735 | { |
3736 | struct task_struct *curr = current; | |
3737 | int i; | |
3738 | ||
a24fc60d PZ |
3739 | if (unlikely(!debug_locks)) |
3740 | return; | |
3741 | ||
f607c668 | 3742 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
3743 | struct held_lock *hlock = curr->held_locks + i; |
3744 | ||
a24fc60d PZ |
3745 | if (match_held_lock(hlock, lock)) { |
3746 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
3747 | return; | |
3748 | ||
e7904a28 PZ |
3749 | hlock->pin_count -= cookie.val; |
3750 | ||
3751 | if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n")) | |
3752 | hlock->pin_count = 0; | |
3753 | ||
a24fc60d PZ |
3754 | return; |
3755 | } | |
f607c668 PZ |
3756 | } |
3757 | ||
a24fc60d | 3758 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
3759 | } |
3760 | ||
fbb9ce95 IM |
3761 | /* |
3762 | * Check whether we follow the irq-flags state precisely: | |
3763 | */ | |
1d09daa5 | 3764 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3765 | { |
992860e9 IM |
3766 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3767 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3768 | if (!debug_locks) |
3769 | return; | |
3770 | ||
5f9fa8a6 IM |
3771 | if (irqs_disabled_flags(flags)) { |
3772 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3773 | printk("possible reason: unannotated irqs-off.\n"); | |
3774 | } | |
3775 | } else { | |
3776 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3777 | printk("possible reason: unannotated irqs-on.\n"); | |
3778 | } | |
3779 | } | |
fbb9ce95 IM |
3780 | |
3781 | /* | |
3782 | * We dont accurately track softirq state in e.g. | |
3783 | * hardirq contexts (such as on 4KSTACKS), so only | |
3784 | * check if not in hardirq contexts: | |
3785 | */ | |
3786 | if (!hardirq_count()) { | |
0119fee4 PZ |
3787 | if (softirq_count()) { |
3788 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3789 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3790 | } else { |
3791 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3792 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3793 | } |
fbb9ce95 IM |
3794 | } |
3795 | ||
3796 | if (!debug_locks) | |
3797 | print_irqtrace_events(current); | |
3798 | #endif | |
3799 | } | |
3800 | ||
00ef9f73 PZ |
3801 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3802 | struct lock_class_key *key, unsigned int subclass, | |
3803 | unsigned long ip) | |
64aa348e PZ |
3804 | { |
3805 | unsigned long flags; | |
3806 | ||
3807 | if (unlikely(current->lockdep_recursion)) | |
3808 | return; | |
3809 | ||
3810 | raw_local_irq_save(flags); | |
3811 | current->lockdep_recursion = 1; | |
3812 | check_flags(flags); | |
00ef9f73 | 3813 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3814 | check_chain_key(current); |
3815 | current->lockdep_recursion = 0; | |
3816 | raw_local_irq_restore(flags); | |
3817 | } | |
00ef9f73 | 3818 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3819 | |
6419c4af O |
3820 | void lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
3821 | { | |
3822 | unsigned long flags; | |
3823 | ||
3824 | if (unlikely(current->lockdep_recursion)) | |
3825 | return; | |
3826 | ||
3827 | raw_local_irq_save(flags); | |
3828 | current->lockdep_recursion = 1; | |
3829 | check_flags(flags); | |
3830 | if (__lock_downgrade(lock, ip)) | |
3831 | check_chain_key(current); | |
3832 | current->lockdep_recursion = 0; | |
3833 | raw_local_irq_restore(flags); | |
3834 | } | |
3835 | EXPORT_SYMBOL_GPL(lock_downgrade); | |
3836 | ||
fbb9ce95 IM |
3837 | /* |
3838 | * We are not always called with irqs disabled - do that here, | |
3839 | * and also avoid lockdep recursion: | |
3840 | */ | |
1d09daa5 | 3841 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3842 | int trylock, int read, int check, |
3843 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3844 | { |
3845 | unsigned long flags; | |
3846 | ||
3847 | if (unlikely(current->lockdep_recursion)) | |
3848 | return; | |
3849 | ||
3850 | raw_local_irq_save(flags); | |
3851 | check_flags(flags); | |
3852 | ||
3853 | current->lockdep_recursion = 1; | |
db2c4c77 | 3854 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3855 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 3856 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
3857 | current->lockdep_recursion = 0; |
3858 | raw_local_irq_restore(flags); | |
3859 | } | |
fbb9ce95 IM |
3860 | EXPORT_SYMBOL_GPL(lock_acquire); |
3861 | ||
1d09daa5 | 3862 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3863 | unsigned long ip) |
fbb9ce95 IM |
3864 | { |
3865 | unsigned long flags; | |
3866 | ||
3867 | if (unlikely(current->lockdep_recursion)) | |
3868 | return; | |
3869 | ||
3870 | raw_local_irq_save(flags); | |
3871 | check_flags(flags); | |
3872 | current->lockdep_recursion = 1; | |
93135439 | 3873 | trace_lock_release(lock, ip); |
e0f56fd7 PZ |
3874 | if (__lock_release(lock, nested, ip)) |
3875 | check_chain_key(current); | |
fbb9ce95 IM |
3876 | current->lockdep_recursion = 0; |
3877 | raw_local_irq_restore(flags); | |
3878 | } | |
fbb9ce95 IM |
3879 | EXPORT_SYMBOL_GPL(lock_release); |
3880 | ||
f8319483 | 3881 | int lock_is_held_type(struct lockdep_map *lock, int read) |
f607c668 PZ |
3882 | { |
3883 | unsigned long flags; | |
3884 | int ret = 0; | |
3885 | ||
3886 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3887 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3888 | |
3889 | raw_local_irq_save(flags); | |
3890 | check_flags(flags); | |
3891 | ||
3892 | current->lockdep_recursion = 1; | |
f8319483 | 3893 | ret = __lock_is_held(lock, read); |
f607c668 PZ |
3894 | current->lockdep_recursion = 0; |
3895 | raw_local_irq_restore(flags); | |
3896 | ||
3897 | return ret; | |
3898 | } | |
f8319483 | 3899 | EXPORT_SYMBOL_GPL(lock_is_held_type); |
f607c668 | 3900 | |
e7904a28 | 3901 | struct pin_cookie lock_pin_lock(struct lockdep_map *lock) |
a24fc60d | 3902 | { |
e7904a28 | 3903 | struct pin_cookie cookie = NIL_COOKIE; |
a24fc60d PZ |
3904 | unsigned long flags; |
3905 | ||
3906 | if (unlikely(current->lockdep_recursion)) | |
e7904a28 | 3907 | return cookie; |
a24fc60d PZ |
3908 | |
3909 | raw_local_irq_save(flags); | |
3910 | check_flags(flags); | |
3911 | ||
3912 | current->lockdep_recursion = 1; | |
e7904a28 | 3913 | cookie = __lock_pin_lock(lock); |
a24fc60d PZ |
3914 | current->lockdep_recursion = 0; |
3915 | raw_local_irq_restore(flags); | |
e7904a28 PZ |
3916 | |
3917 | return cookie; | |
a24fc60d PZ |
3918 | } |
3919 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
3920 | ||
e7904a28 PZ |
3921 | void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
3922 | { | |
3923 | unsigned long flags; | |
3924 | ||
3925 | if (unlikely(current->lockdep_recursion)) | |
3926 | return; | |
3927 | ||
3928 | raw_local_irq_save(flags); | |
3929 | check_flags(flags); | |
3930 | ||
3931 | current->lockdep_recursion = 1; | |
3932 | __lock_repin_lock(lock, cookie); | |
3933 | current->lockdep_recursion = 0; | |
3934 | raw_local_irq_restore(flags); | |
3935 | } | |
3936 | EXPORT_SYMBOL_GPL(lock_repin_lock); | |
3937 | ||
3938 | void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
a24fc60d PZ |
3939 | { |
3940 | unsigned long flags; | |
3941 | ||
3942 | if (unlikely(current->lockdep_recursion)) | |
3943 | return; | |
3944 | ||
3945 | raw_local_irq_save(flags); | |
3946 | check_flags(flags); | |
3947 | ||
3948 | current->lockdep_recursion = 1; | |
e7904a28 | 3949 | __lock_unpin_lock(lock, cookie); |
a24fc60d PZ |
3950 | current->lockdep_recursion = 0; |
3951 | raw_local_irq_restore(flags); | |
3952 | } | |
3953 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
3954 | ||
cf40bd16 NP |
3955 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3956 | { | |
7dea19f9 | 3957 | current->lockdep_reclaim_gfp = current_gfp_context(gfp_mask); |
cf40bd16 | 3958 | } |
05df49e7 | 3959 | EXPORT_SYMBOL_GPL(lockdep_set_current_reclaim_state); |
cf40bd16 NP |
3960 | |
3961 | void lockdep_clear_current_reclaim_state(void) | |
3962 | { | |
3963 | current->lockdep_reclaim_gfp = 0; | |
3964 | } | |
05df49e7 | 3965 | EXPORT_SYMBOL_GPL(lockdep_clear_current_reclaim_state); |
cf40bd16 | 3966 | |
f20786ff PZ |
3967 | #ifdef CONFIG_LOCK_STAT |
3968 | static int | |
3969 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3970 | unsigned long ip) | |
3971 | { | |
3972 | if (!debug_locks_off()) | |
3973 | return 0; | |
3974 | if (debug_locks_silent) | |
3975 | return 0; | |
3976 | ||
b3fbab05 | 3977 | printk("\n"); |
a5dd63ef PM |
3978 | pr_warn("=================================\n"); |
3979 | pr_warn("WARNING: bad contention detected!\n"); | |
fbdc4b9a | 3980 | print_kernel_ident(); |
a5dd63ef | 3981 | pr_warn("---------------------------------\n"); |
f20786ff | 3982 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3983 | curr->comm, task_pid_nr(curr)); |
f20786ff | 3984 | print_lockdep_cache(lock); |
f943fe0f | 3985 | printk(KERN_CONT ") at:\n"); |
f20786ff PZ |
3986 | print_ip_sym(ip); |
3987 | printk("but there are no locks held!\n"); | |
3988 | printk("\nother info that might help us debug this:\n"); | |
3989 | lockdep_print_held_locks(curr); | |
3990 | ||
3991 | printk("\nstack backtrace:\n"); | |
3992 | dump_stack(); | |
3993 | ||
3994 | return 0; | |
3995 | } | |
3996 | ||
3997 | static void | |
3998 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3999 | { | |
4000 | struct task_struct *curr = current; | |
41c2c5b8 | 4001 | struct held_lock *hlock; |
f20786ff PZ |
4002 | struct lock_class_stats *stats; |
4003 | unsigned int depth; | |
c7e78cff | 4004 | int i, contention_point, contending_point; |
f20786ff PZ |
4005 | |
4006 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4007 | /* |
4008 | * Whee, we contended on this lock, except it seems we're not | |
4009 | * actually trying to acquire anything much at all.. | |
4010 | */ | |
f20786ff PZ |
4011 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4012 | return; | |
4013 | ||
41c2c5b8 O |
4014 | hlock = find_held_lock(curr, lock, depth, &i); |
4015 | if (!hlock) { | |
4016 | print_lock_contention_bug(curr, lock, ip); | |
4017 | return; | |
f20786ff | 4018 | } |
f20786ff | 4019 | |
bb97a91e PZ |
4020 | if (hlock->instance != lock) |
4021 | return; | |
4022 | ||
3365e779 | 4023 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 4024 | |
c7e78cff PZ |
4025 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
4026 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
4027 | lock->ip); | |
f20786ff | 4028 | |
f82b217e | 4029 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
4030 | if (contention_point < LOCKSTAT_POINTS) |
4031 | stats->contention_point[contention_point]++; | |
4032 | if (contending_point < LOCKSTAT_POINTS) | |
4033 | stats->contending_point[contending_point]++; | |
96645678 PZ |
4034 | if (lock->cpu != smp_processor_id()) |
4035 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
4036 | put_lock_stats(stats); |
4037 | } | |
4038 | ||
4039 | static void | |
c7e78cff | 4040 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4041 | { |
4042 | struct task_struct *curr = current; | |
41c2c5b8 | 4043 | struct held_lock *hlock; |
f20786ff PZ |
4044 | struct lock_class_stats *stats; |
4045 | unsigned int depth; | |
3365e779 | 4046 | u64 now, waittime = 0; |
96645678 | 4047 | int i, cpu; |
f20786ff PZ |
4048 | |
4049 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4050 | /* |
4051 | * Yay, we acquired ownership of this lock we didn't try to | |
4052 | * acquire, how the heck did that happen? | |
4053 | */ | |
f20786ff PZ |
4054 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4055 | return; | |
4056 | ||
41c2c5b8 O |
4057 | hlock = find_held_lock(curr, lock, depth, &i); |
4058 | if (!hlock) { | |
4059 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
4060 | return; | |
f20786ff | 4061 | } |
f20786ff | 4062 | |
bb97a91e PZ |
4063 | if (hlock->instance != lock) |
4064 | return; | |
4065 | ||
96645678 PZ |
4066 | cpu = smp_processor_id(); |
4067 | if (hlock->waittime_stamp) { | |
3365e779 | 4068 | now = lockstat_clock(); |
96645678 PZ |
4069 | waittime = now - hlock->waittime_stamp; |
4070 | hlock->holdtime_stamp = now; | |
4071 | } | |
f20786ff | 4072 | |
883a2a31 | 4073 | trace_lock_acquired(lock, ip); |
2062501a | 4074 | |
f82b217e | 4075 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
4076 | if (waittime) { |
4077 | if (hlock->read) | |
4078 | lock_time_inc(&stats->read_waittime, waittime); | |
4079 | else | |
4080 | lock_time_inc(&stats->write_waittime, waittime); | |
4081 | } | |
4082 | if (lock->cpu != cpu) | |
4083 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 4084 | put_lock_stats(stats); |
96645678 PZ |
4085 | |
4086 | lock->cpu = cpu; | |
c7e78cff | 4087 | lock->ip = ip; |
f20786ff PZ |
4088 | } |
4089 | ||
4090 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4091 | { | |
4092 | unsigned long flags; | |
4093 | ||
4094 | if (unlikely(!lock_stat)) | |
4095 | return; | |
4096 | ||
4097 | if (unlikely(current->lockdep_recursion)) | |
4098 | return; | |
4099 | ||
4100 | raw_local_irq_save(flags); | |
4101 | check_flags(flags); | |
4102 | current->lockdep_recursion = 1; | |
db2c4c77 | 4103 | trace_lock_contended(lock, ip); |
f20786ff PZ |
4104 | __lock_contended(lock, ip); |
4105 | current->lockdep_recursion = 0; | |
4106 | raw_local_irq_restore(flags); | |
4107 | } | |
4108 | EXPORT_SYMBOL_GPL(lock_contended); | |
4109 | ||
c7e78cff | 4110 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4111 | { |
4112 | unsigned long flags; | |
4113 | ||
4114 | if (unlikely(!lock_stat)) | |
4115 | return; | |
4116 | ||
4117 | if (unlikely(current->lockdep_recursion)) | |
4118 | return; | |
4119 | ||
4120 | raw_local_irq_save(flags); | |
4121 | check_flags(flags); | |
4122 | current->lockdep_recursion = 1; | |
c7e78cff | 4123 | __lock_acquired(lock, ip); |
f20786ff PZ |
4124 | current->lockdep_recursion = 0; |
4125 | raw_local_irq_restore(flags); | |
4126 | } | |
4127 | EXPORT_SYMBOL_GPL(lock_acquired); | |
4128 | #endif | |
4129 | ||
fbb9ce95 IM |
4130 | /* |
4131 | * Used by the testsuite, sanitize the validator state | |
4132 | * after a simulated failure: | |
4133 | */ | |
4134 | ||
4135 | void lockdep_reset(void) | |
4136 | { | |
4137 | unsigned long flags; | |
23d95a03 | 4138 | int i; |
fbb9ce95 IM |
4139 | |
4140 | raw_local_irq_save(flags); | |
4141 | current->curr_chain_key = 0; | |
4142 | current->lockdep_depth = 0; | |
4143 | current->lockdep_recursion = 0; | |
4144 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
4145 | nr_hardirq_chains = 0; | |
4146 | nr_softirq_chains = 0; | |
4147 | nr_process_chains = 0; | |
4148 | debug_locks = 1; | |
23d95a03 | 4149 | for (i = 0; i < CHAINHASH_SIZE; i++) |
a63f38cc | 4150 | INIT_HLIST_HEAD(chainhash_table + i); |
fbb9ce95 IM |
4151 | raw_local_irq_restore(flags); |
4152 | } | |
4153 | ||
4154 | static void zap_class(struct lock_class *class) | |
4155 | { | |
4156 | int i; | |
4157 | ||
4158 | /* | |
4159 | * Remove all dependencies this lock is | |
4160 | * involved in: | |
4161 | */ | |
4162 | for (i = 0; i < nr_list_entries; i++) { | |
4163 | if (list_entries[i].class == class) | |
4164 | list_del_rcu(&list_entries[i].entry); | |
4165 | } | |
4166 | /* | |
4167 | * Unhash the class and remove it from the all_lock_classes list: | |
4168 | */ | |
a63f38cc | 4169 | hlist_del_rcu(&class->hash_entry); |
fbb9ce95 IM |
4170 | list_del_rcu(&class->lock_entry); |
4171 | ||
cee34d88 PZ |
4172 | RCU_INIT_POINTER(class->key, NULL); |
4173 | RCU_INIT_POINTER(class->name, NULL); | |
fbb9ce95 IM |
4174 | } |
4175 | ||
fabe874a | 4176 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
4177 | { |
4178 | return addr >= start && addr < start + size; | |
4179 | } | |
4180 | ||
35a9393c PZ |
4181 | /* |
4182 | * Used in module.c to remove lock classes from memory that is going to be | |
4183 | * freed; and possibly re-used by other modules. | |
4184 | * | |
4185 | * We will have had one sync_sched() before getting here, so we're guaranteed | |
4186 | * nobody will look up these exact classes -- they're properly dead but still | |
4187 | * allocated. | |
4188 | */ | |
fbb9ce95 IM |
4189 | void lockdep_free_key_range(void *start, unsigned long size) |
4190 | { | |
35a9393c | 4191 | struct lock_class *class; |
a63f38cc | 4192 | struct hlist_head *head; |
fbb9ce95 IM |
4193 | unsigned long flags; |
4194 | int i; | |
5a26db5b | 4195 | int locked; |
fbb9ce95 IM |
4196 | |
4197 | raw_local_irq_save(flags); | |
5a26db5b | 4198 | locked = graph_lock(); |
fbb9ce95 IM |
4199 | |
4200 | /* | |
4201 | * Unhash all classes that were created by this module: | |
4202 | */ | |
4203 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
4204 | head = classhash_table + i; | |
a63f38cc | 4205 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
fbb9ce95 IM |
4206 | if (within(class->key, start, size)) |
4207 | zap_class(class); | |
fabe874a AV |
4208 | else if (within(class->name, start, size)) |
4209 | zap_class(class); | |
4210 | } | |
fbb9ce95 IM |
4211 | } |
4212 | ||
5a26db5b NP |
4213 | if (locked) |
4214 | graph_unlock(); | |
fbb9ce95 | 4215 | raw_local_irq_restore(flags); |
35a9393c PZ |
4216 | |
4217 | /* | |
4218 | * Wait for any possible iterators from look_up_lock_class() to pass | |
4219 | * before continuing to free the memory they refer to. | |
4220 | * | |
4221 | * sync_sched() is sufficient because the read-side is IRQ disable. | |
4222 | */ | |
4223 | synchronize_sched(); | |
4224 | ||
4225 | /* | |
4226 | * XXX at this point we could return the resources to the pool; | |
4227 | * instead we leak them. We would need to change to bitmap allocators | |
4228 | * instead of the linear allocators we have now. | |
4229 | */ | |
fbb9ce95 IM |
4230 | } |
4231 | ||
4232 | void lockdep_reset_lock(struct lockdep_map *lock) | |
4233 | { | |
35a9393c | 4234 | struct lock_class *class; |
a63f38cc | 4235 | struct hlist_head *head; |
fbb9ce95 IM |
4236 | unsigned long flags; |
4237 | int i, j; | |
5a26db5b | 4238 | int locked; |
fbb9ce95 IM |
4239 | |
4240 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
4241 | |
4242 | /* | |
d6d897ce IM |
4243 | * Remove all classes this lock might have: |
4244 | */ | |
4245 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
4246 | /* | |
4247 | * If the class exists we look it up and zap it: | |
4248 | */ | |
4249 | class = look_up_lock_class(lock, j); | |
383776fa | 4250 | if (!IS_ERR_OR_NULL(class)) |
d6d897ce IM |
4251 | zap_class(class); |
4252 | } | |
4253 | /* | |
4254 | * Debug check: in the end all mapped classes should | |
4255 | * be gone. | |
fbb9ce95 | 4256 | */ |
5a26db5b | 4257 | locked = graph_lock(); |
fbb9ce95 IM |
4258 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
4259 | head = classhash_table + i; | |
a63f38cc | 4260 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
62016250 HM |
4261 | int match = 0; |
4262 | ||
4263 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
4264 | match |= class == lock->class_cache[j]; | |
4265 | ||
4266 | if (unlikely(match)) { | |
0119fee4 PZ |
4267 | if (debug_locks_off_graph_unlock()) { |
4268 | /* | |
4269 | * We all just reset everything, how did it match? | |
4270 | */ | |
74c383f1 | 4271 | WARN_ON(1); |
0119fee4 | 4272 | } |
d6d897ce | 4273 | goto out_restore; |
fbb9ce95 IM |
4274 | } |
4275 | } | |
4276 | } | |
5a26db5b NP |
4277 | if (locked) |
4278 | graph_unlock(); | |
d6d897ce IM |
4279 | |
4280 | out_restore: | |
fbb9ce95 IM |
4281 | raw_local_irq_restore(flags); |
4282 | } | |
4283 | ||
fbb9ce95 IM |
4284 | void __init lockdep_info(void) |
4285 | { | |
4286 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
4287 | ||
b0788caf | 4288 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
4289 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
4290 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 4291 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
4292 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
4293 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
4294 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
4295 | ||
4296 | printk(" memory used by lock dependency info: %lu kB\n", | |
4297 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
4298 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
4299 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
4300 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 4301 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 4302 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 4303 | + sizeof(struct circular_queue) |
4dd861d6 | 4304 | #endif |
90629209 | 4305 | ) / 1024 |
4dd861d6 | 4306 | ); |
fbb9ce95 IM |
4307 | |
4308 | printk(" per task-struct memory footprint: %lu bytes\n", | |
4309 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
fbb9ce95 IM |
4310 | } |
4311 | ||
fbb9ce95 IM |
4312 | static void |
4313 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 4314 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
4315 | { |
4316 | if (!debug_locks_off()) | |
4317 | return; | |
4318 | if (debug_locks_silent) | |
4319 | return; | |
4320 | ||
b3fbab05 | 4321 | printk("\n"); |
a5dd63ef PM |
4322 | pr_warn("=========================\n"); |
4323 | pr_warn("WARNING: held lock freed!\n"); | |
fbdc4b9a | 4324 | print_kernel_ident(); |
a5dd63ef | 4325 | pr_warn("-------------------------\n"); |
fbb9ce95 | 4326 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 4327 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 4328 | print_lock(hlock); |
fbb9ce95 IM |
4329 | lockdep_print_held_locks(curr); |
4330 | ||
4331 | printk("\nstack backtrace:\n"); | |
4332 | dump_stack(); | |
4333 | } | |
4334 | ||
54561783 ON |
4335 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4336 | const void* lock_from, unsigned long lock_len) | |
4337 | { | |
4338 | return lock_from + lock_len <= mem_from || | |
4339 | mem_from + mem_len <= lock_from; | |
4340 | } | |
4341 | ||
fbb9ce95 IM |
4342 | /* |
4343 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4344 | * is destroyed or reinitialized - this code checks whether there is | |
4345 | * any held lock in the memory range of <from> to <to>: | |
4346 | */ | |
4347 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4348 | { | |
fbb9ce95 IM |
4349 | struct task_struct *curr = current; |
4350 | struct held_lock *hlock; | |
4351 | unsigned long flags; | |
4352 | int i; | |
4353 | ||
4354 | if (unlikely(!debug_locks)) | |
4355 | return; | |
4356 | ||
4357 | local_irq_save(flags); | |
4358 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4359 | hlock = curr->held_locks + i; | |
4360 | ||
54561783 ON |
4361 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4362 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4363 | continue; |
4364 | ||
54561783 | 4365 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4366 | break; |
4367 | } | |
4368 | local_irq_restore(flags); | |
4369 | } | |
ed07536e | 4370 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 4371 | |
1b1d2fb4 | 4372 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
4373 | { |
4374 | if (!debug_locks_off()) | |
4375 | return; | |
4376 | if (debug_locks_silent) | |
4377 | return; | |
4378 | ||
b3fbab05 | 4379 | printk("\n"); |
a5dd63ef PM |
4380 | pr_warn("====================================\n"); |
4381 | pr_warn("WARNING: %s/%d still has locks held!\n", | |
1b1d2fb4 | 4382 | current->comm, task_pid_nr(current)); |
fbdc4b9a | 4383 | print_kernel_ident(); |
a5dd63ef | 4384 | pr_warn("------------------------------------\n"); |
1b1d2fb4 | 4385 | lockdep_print_held_locks(current); |
fbb9ce95 IM |
4386 | printk("\nstack backtrace:\n"); |
4387 | dump_stack(); | |
4388 | } | |
4389 | ||
1b1d2fb4 | 4390 | void debug_check_no_locks_held(void) |
fbb9ce95 | 4391 | { |
1b1d2fb4 CC |
4392 | if (unlikely(current->lockdep_depth > 0)) |
4393 | print_held_locks_bug(); | |
fbb9ce95 | 4394 | } |
1b1d2fb4 | 4395 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 4396 | |
8dce7a9a | 4397 | #ifdef __KERNEL__ |
fbb9ce95 IM |
4398 | void debug_show_all_locks(void) |
4399 | { | |
4400 | struct task_struct *g, *p; | |
4401 | int count = 10; | |
4402 | int unlock = 1; | |
4403 | ||
9c35dd7f JP |
4404 | if (unlikely(!debug_locks)) { |
4405 | printk("INFO: lockdep is turned off.\n"); | |
4406 | return; | |
4407 | } | |
fbb9ce95 IM |
4408 | printk("\nShowing all locks held in the system:\n"); |
4409 | ||
4410 | /* | |
4411 | * Here we try to get the tasklist_lock as hard as possible, | |
4412 | * if not successful after 2 seconds we ignore it (but keep | |
4413 | * trying). This is to enable a debug printout even if a | |
4414 | * tasklist_lock-holding task deadlocks or crashes. | |
4415 | */ | |
4416 | retry: | |
4417 | if (!read_trylock(&tasklist_lock)) { | |
4418 | if (count == 10) | |
4419 | printk("hm, tasklist_lock locked, retrying... "); | |
4420 | if (count) { | |
4421 | count--; | |
4422 | printk(" #%d", 10-count); | |
4423 | mdelay(200); | |
4424 | goto retry; | |
4425 | } | |
4426 | printk(" ignoring it.\n"); | |
4427 | unlock = 0; | |
46fec7ac | 4428 | } else { |
4429 | if (count != 10) | |
4430 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 4431 | } |
fbb9ce95 IM |
4432 | |
4433 | do_each_thread(g, p) { | |
85684873 IM |
4434 | /* |
4435 | * It's not reliable to print a task's held locks | |
4436 | * if it's not sleeping (or if it's not the current | |
4437 | * task): | |
4438 | */ | |
4439 | if (p->state == TASK_RUNNING && p != current) | |
4440 | continue; | |
fbb9ce95 IM |
4441 | if (p->lockdep_depth) |
4442 | lockdep_print_held_locks(p); | |
4443 | if (!unlock) | |
4444 | if (read_trylock(&tasklist_lock)) | |
4445 | unlock = 1; | |
4446 | } while_each_thread(g, p); | |
4447 | ||
4448 | printk("\n"); | |
a5dd63ef | 4449 | pr_warn("=============================================\n\n"); |
fbb9ce95 IM |
4450 | |
4451 | if (unlock) | |
4452 | read_unlock(&tasklist_lock); | |
4453 | } | |
fbb9ce95 | 4454 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 4455 | #endif |
fbb9ce95 | 4456 | |
82a1fcb9 IM |
4457 | /* |
4458 | * Careful: only use this function if you are sure that | |
4459 | * the task cannot run in parallel! | |
4460 | */ | |
f1b499f0 | 4461 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4462 | { |
9c35dd7f JP |
4463 | if (unlikely(!debug_locks)) { |
4464 | printk("INFO: lockdep is turned off.\n"); | |
4465 | return; | |
4466 | } | |
fbb9ce95 IM |
4467 | lockdep_print_held_locks(task); |
4468 | } | |
fbb9ce95 | 4469 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 4470 | |
722a9f92 | 4471 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
4472 | { |
4473 | struct task_struct *curr = current; | |
4474 | ||
4475 | if (unlikely(curr->lockdep_depth)) { | |
4476 | if (!debug_locks_off()) | |
4477 | return; | |
b3fbab05 | 4478 | printk("\n"); |
a5dd63ef PM |
4479 | pr_warn("================================================\n"); |
4480 | pr_warn("WARNING: lock held when returning to user space!\n"); | |
fbdc4b9a | 4481 | print_kernel_ident(); |
a5dd63ef | 4482 | pr_warn("------------------------------------------------\n"); |
b351d164 PZ |
4483 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4484 | curr->comm, curr->pid); | |
4485 | lockdep_print_held_locks(curr); | |
4486 | } | |
4487 | } | |
0632eb3d | 4488 | |
b3fbab05 | 4489 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4490 | { |
4491 | struct task_struct *curr = current; | |
4492 | ||
2b3fc35f | 4493 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4494 | if (!debug_locks_off()) |
4495 | return; | |
2b3fc35f LJ |
4496 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4497 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 | 4498 | printk("\n"); |
a5dd63ef PM |
4499 | pr_warn("=============================\n"); |
4500 | pr_warn("WARNING: suspicious RCU usage\n"); | |
fbdc4b9a | 4501 | print_kernel_ident(); |
a5dd63ef PM |
4502 | pr_warn("-----------------------------\n"); |
4503 | printk("%s:%d %s!\n", file, line, s); | |
4504 | printk("\nother info that might help us debug this:\n\n"); | |
4505 | printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n", | |
c5fdcec9 PM |
4506 | !rcu_lockdep_current_cpu_online() |
4507 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 4508 | : !rcu_is_watching() |
c5fdcec9 PM |
4509 | ? "RCU used illegally from idle CPU!\n" |
4510 | : "", | |
4511 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
4512 | |
4513 | /* | |
4514 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
4515 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
4516 | * considers that CPU to be in an "extended quiescent state", | |
4517 | * which means that RCU will be completely ignoring that CPU. | |
4518 | * Therefore, rcu_read_lock() and friends have absolutely no | |
4519 | * effect on a CPU running in that state. In other words, even if | |
4520 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
4521 | * delete data structures out from under it. RCU really has no | |
4522 | * choice here: we need to keep an RCU-free window in idle where | |
4523 | * the CPU may possibly enter into low power mode. This way we can | |
4524 | * notice an extended quiescent state to other CPUs that started a grace | |
4525 | * period. Otherwise we would delay any grace period as long as we run | |
4526 | * in the idle task. | |
4527 | * | |
4528 | * So complain bitterly if someone does call rcu_read_lock(), | |
4529 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
4530 | */ | |
5c173eb8 | 4531 | if (!rcu_is_watching()) |
0464e937 FW |
4532 | printk("RCU used illegally from extended quiescent state!\n"); |
4533 | ||
0632eb3d PM |
4534 | lockdep_print_held_locks(curr); |
4535 | printk("\nstack backtrace:\n"); | |
4536 | dump_stack(); | |
4537 | } | |
b3fbab05 | 4538 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |