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Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 | 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 | |
b09be676 BP |
61 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE |
62 | #include <linux/slab.h> | |
63 | #endif | |
64 | ||
f20786ff PZ |
65 | #ifdef CONFIG_PROVE_LOCKING |
66 | int prove_locking = 1; | |
67 | module_param(prove_locking, int, 0644); | |
68 | #else | |
69 | #define prove_locking 0 | |
70 | #endif | |
71 | ||
72 | #ifdef CONFIG_LOCK_STAT | |
73 | int lock_stat = 1; | |
74 | module_param(lock_stat, int, 0644); | |
75 | #else | |
76 | #define lock_stat 0 | |
77 | #endif | |
78 | ||
fbb9ce95 | 79 | /* |
74c383f1 IM |
80 | * lockdep_lock: protects the lockdep graph, the hashes and the |
81 | * class/list/hash allocators. | |
fbb9ce95 IM |
82 | * |
83 | * This is one of the rare exceptions where it's justified | |
84 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 85 | * code to recurse back into the lockdep code... |
fbb9ce95 | 86 | */ |
edc35bd7 | 87 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
88 | |
89 | static int graph_lock(void) | |
90 | { | |
0199c4e6 | 91 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
92 | /* |
93 | * Make sure that if another CPU detected a bug while | |
94 | * walking the graph we dont change it (while the other | |
95 | * CPU is busy printing out stuff with the graph lock | |
96 | * dropped already) | |
97 | */ | |
98 | if (!debug_locks) { | |
0199c4e6 | 99 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
100 | return 0; |
101 | } | |
bb065afb SR |
102 | /* prevent any recursions within lockdep from causing deadlocks */ |
103 | current->lockdep_recursion++; | |
74c383f1 IM |
104 | return 1; |
105 | } | |
106 | ||
107 | static inline int graph_unlock(void) | |
108 | { | |
0119fee4 PZ |
109 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
110 | /* | |
111 | * The lockdep graph lock isn't locked while we expect it to | |
112 | * be, we're confused now, bye! | |
113 | */ | |
381a2292 | 114 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 115 | } |
381a2292 | 116 | |
bb065afb | 117 | current->lockdep_recursion--; |
0199c4e6 | 118 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
119 | return 0; |
120 | } | |
121 | ||
122 | /* | |
123 | * Turn lock debugging off and return with 0 if it was off already, | |
124 | * and also release the graph lock: | |
125 | */ | |
126 | static inline int debug_locks_off_graph_unlock(void) | |
127 | { | |
128 | int ret = debug_locks_off(); | |
129 | ||
0199c4e6 | 130 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
131 | |
132 | return ret; | |
133 | } | |
fbb9ce95 | 134 | |
fbb9ce95 | 135 | unsigned long nr_list_entries; |
af012961 | 136 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 137 | |
fbb9ce95 IM |
138 | /* |
139 | * All data structures here are protected by the global debug_lock. | |
140 | * | |
141 | * Mutex key structs only get allocated, once during bootup, and never | |
142 | * get freed - this significantly simplifies the debugging code. | |
143 | */ | |
144 | unsigned long nr_lock_classes; | |
145 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
146 | ||
f82b217e DJ |
147 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
148 | { | |
149 | if (!hlock->class_idx) { | |
0119fee4 PZ |
150 | /* |
151 | * Someone passed in garbage, we give up. | |
152 | */ | |
f82b217e DJ |
153 | DEBUG_LOCKS_WARN_ON(1); |
154 | return NULL; | |
155 | } | |
156 | return lock_classes + hlock->class_idx - 1; | |
157 | } | |
158 | ||
f20786ff | 159 | #ifdef CONFIG_LOCK_STAT |
25528213 | 160 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
f20786ff | 161 | |
3365e779 PZ |
162 | static inline u64 lockstat_clock(void) |
163 | { | |
c676329a | 164 | return local_clock(); |
3365e779 PZ |
165 | } |
166 | ||
c7e78cff | 167 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
168 | { |
169 | int i; | |
170 | ||
c7e78cff PZ |
171 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
172 | if (points[i] == 0) { | |
173 | points[i] = ip; | |
f20786ff PZ |
174 | break; |
175 | } | |
c7e78cff | 176 | if (points[i] == ip) |
f20786ff PZ |
177 | break; |
178 | } | |
179 | ||
180 | return i; | |
181 | } | |
182 | ||
3365e779 | 183 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
184 | { |
185 | if (time > lt->max) | |
186 | lt->max = time; | |
187 | ||
109d71c6 | 188 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
189 | lt->min = time; |
190 | ||
191 | lt->total += time; | |
192 | lt->nr++; | |
193 | } | |
194 | ||
c46261de PZ |
195 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
196 | { | |
109d71c6 FR |
197 | if (!src->nr) |
198 | return; | |
199 | ||
200 | if (src->max > dst->max) | |
201 | dst->max = src->max; | |
202 | ||
203 | if (src->min < dst->min || !dst->nr) | |
204 | dst->min = src->min; | |
205 | ||
c46261de PZ |
206 | dst->total += src->total; |
207 | dst->nr += src->nr; | |
208 | } | |
209 | ||
210 | struct lock_class_stats lock_stats(struct lock_class *class) | |
211 | { | |
212 | struct lock_class_stats stats; | |
213 | int cpu, i; | |
214 | ||
215 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
216 | for_each_possible_cpu(cpu) { | |
217 | struct lock_class_stats *pcs = | |
1871e52c | 218 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
219 | |
220 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
221 | stats.contention_point[i] += pcs->contention_point[i]; | |
222 | ||
c7e78cff PZ |
223 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
224 | stats.contending_point[i] += pcs->contending_point[i]; | |
225 | ||
c46261de PZ |
226 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
227 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
228 | ||
229 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
230 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
231 | |
232 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
233 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
234 | } |
235 | ||
236 | return stats; | |
237 | } | |
238 | ||
239 | void clear_lock_stats(struct lock_class *class) | |
240 | { | |
241 | int cpu; | |
242 | ||
243 | for_each_possible_cpu(cpu) { | |
244 | struct lock_class_stats *cpu_stats = | |
1871e52c | 245 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
246 | |
247 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
248 | } | |
249 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 250 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
251 | } |
252 | ||
f20786ff PZ |
253 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
254 | { | |
1871e52c | 255 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
256 | } |
257 | ||
258 | static void put_lock_stats(struct lock_class_stats *stats) | |
259 | { | |
1871e52c | 260 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
261 | } |
262 | ||
263 | static void lock_release_holdtime(struct held_lock *hlock) | |
264 | { | |
265 | struct lock_class_stats *stats; | |
3365e779 | 266 | u64 holdtime; |
f20786ff PZ |
267 | |
268 | if (!lock_stat) | |
269 | return; | |
270 | ||
3365e779 | 271 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 272 | |
f82b217e | 273 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
274 | if (hlock->read) |
275 | lock_time_inc(&stats->read_holdtime, holdtime); | |
276 | else | |
277 | lock_time_inc(&stats->write_holdtime, holdtime); | |
278 | put_lock_stats(stats); | |
279 | } | |
280 | #else | |
281 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
282 | { | |
283 | } | |
284 | #endif | |
285 | ||
fbb9ce95 IM |
286 | /* |
287 | * We keep a global list of all lock classes. The list only grows, | |
288 | * never shrinks. The list is only accessed with the lockdep | |
289 | * spinlock lock held. | |
290 | */ | |
291 | LIST_HEAD(all_lock_classes); | |
292 | ||
293 | /* | |
294 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
295 | */ | |
296 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
297 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 298 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
299 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
300 | ||
a63f38cc | 301 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
fbb9ce95 | 302 | |
fbb9ce95 IM |
303 | /* |
304 | * We put the lock dependency chains into a hash-table as well, to cache | |
305 | * their existence: | |
306 | */ | |
307 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
308 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 309 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
310 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
311 | ||
a63f38cc | 312 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
fbb9ce95 IM |
313 | |
314 | /* | |
315 | * The hash key of the lock dependency chains is a hash itself too: | |
316 | * it's a hash of all locks taken up to that lock, including that lock. | |
317 | * It's a 64-bit hash, because it's important for the keys to be | |
318 | * unique. | |
319 | */ | |
dfaaf3fa PZ |
320 | static inline u64 iterate_chain_key(u64 key, u32 idx) |
321 | { | |
322 | u32 k0 = key, k1 = key >> 32; | |
323 | ||
324 | __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ | |
325 | ||
326 | return k0 | (u64)k1 << 32; | |
327 | } | |
fbb9ce95 | 328 | |
1d09daa5 | 329 | void lockdep_off(void) |
fbb9ce95 IM |
330 | { |
331 | current->lockdep_recursion++; | |
332 | } | |
fbb9ce95 IM |
333 | EXPORT_SYMBOL(lockdep_off); |
334 | ||
1d09daa5 | 335 | void lockdep_on(void) |
fbb9ce95 IM |
336 | { |
337 | current->lockdep_recursion--; | |
338 | } | |
fbb9ce95 IM |
339 | EXPORT_SYMBOL(lockdep_on); |
340 | ||
fbb9ce95 IM |
341 | /* |
342 | * Debugging switches: | |
343 | */ | |
344 | ||
345 | #define VERBOSE 0 | |
33e94e96 | 346 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
347 | |
348 | #if VERBOSE | |
349 | # define HARDIRQ_VERBOSE 1 | |
350 | # define SOFTIRQ_VERBOSE 1 | |
351 | #else | |
352 | # define HARDIRQ_VERBOSE 0 | |
353 | # define SOFTIRQ_VERBOSE 0 | |
354 | #endif | |
355 | ||
d92a8cfc | 356 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE |
fbb9ce95 IM |
357 | /* |
358 | * Quick filtering for interesting events: | |
359 | */ | |
360 | static int class_filter(struct lock_class *class) | |
361 | { | |
f9829cce AK |
362 | #if 0 |
363 | /* Example */ | |
fbb9ce95 | 364 | if (class->name_version == 1 && |
f9829cce | 365 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
366 | return 1; |
367 | if (class->name_version == 1 && | |
f9829cce | 368 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 369 | return 1; |
f9829cce | 370 | #endif |
a6640897 IM |
371 | /* Filter everything else. 1 would be to allow everything else */ |
372 | return 0; | |
fbb9ce95 IM |
373 | } |
374 | #endif | |
375 | ||
376 | static int verbose(struct lock_class *class) | |
377 | { | |
378 | #if VERBOSE | |
379 | return class_filter(class); | |
380 | #endif | |
381 | return 0; | |
382 | } | |
383 | ||
fbb9ce95 IM |
384 | /* |
385 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 386 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
387 | */ |
388 | unsigned long nr_stack_trace_entries; | |
389 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
390 | ||
2c522836 DJ |
391 | static void print_lockdep_off(const char *bug_msg) |
392 | { | |
393 | printk(KERN_DEBUG "%s\n", bug_msg); | |
394 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 395 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 396 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 397 | #endif |
2c522836 DJ |
398 | } |
399 | ||
fbb9ce95 IM |
400 | static int save_trace(struct stack_trace *trace) |
401 | { | |
402 | trace->nr_entries = 0; | |
403 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
404 | trace->entries = stack_trace + nr_stack_trace_entries; | |
405 | ||
5a1b3999 | 406 | trace->skip = 3; |
5a1b3999 | 407 | |
ab1b6f03 | 408 | save_stack_trace(trace); |
fbb9ce95 | 409 | |
4f84f433 PZ |
410 | /* |
411 | * Some daft arches put -1 at the end to indicate its a full trace. | |
412 | * | |
413 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
414 | * complete trace that maxes out the entries provided will be reported | |
415 | * as incomplete, friggin useless </rant> | |
416 | */ | |
ea5b41f9 TL |
417 | if (trace->nr_entries != 0 && |
418 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
419 | trace->nr_entries--; |
420 | ||
fbb9ce95 IM |
421 | trace->max_entries = trace->nr_entries; |
422 | ||
423 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 424 | |
4f84f433 | 425 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
426 | if (!debug_locks_off_graph_unlock()) |
427 | return 0; | |
428 | ||
2c522836 | 429 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
430 | dump_stack(); |
431 | ||
fbb9ce95 IM |
432 | return 0; |
433 | } | |
434 | ||
435 | return 1; | |
436 | } | |
437 | ||
438 | unsigned int nr_hardirq_chains; | |
439 | unsigned int nr_softirq_chains; | |
440 | unsigned int nr_process_chains; | |
441 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
442 | |
443 | #ifdef CONFIG_DEBUG_LOCKDEP | |
fbb9ce95 IM |
444 | /* |
445 | * Various lockdep statistics: | |
446 | */ | |
bd6d29c2 | 447 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
448 | #endif |
449 | ||
450 | /* | |
451 | * Locking printouts: | |
452 | */ | |
453 | ||
fabe9c42 | 454 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
455 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
456 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
457 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
458 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 459 | |
fbb9ce95 IM |
460 | static const char *usage_str[] = |
461 | { | |
fabe9c42 PZ |
462 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
463 | #include "lockdep_states.h" | |
464 | #undef LOCKDEP_STATE | |
465 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
466 | }; |
467 | ||
468 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
469 | { | |
ffb45122 | 470 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
471 | } |
472 | ||
3ff176ca | 473 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 474 | { |
3ff176ca PZ |
475 | return 1UL << bit; |
476 | } | |
fbb9ce95 | 477 | |
3ff176ca PZ |
478 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
479 | { | |
480 | char c = '.'; | |
481 | ||
482 | if (class->usage_mask & lock_flag(bit + 2)) | |
483 | c = '+'; | |
484 | if (class->usage_mask & lock_flag(bit)) { | |
485 | c = '-'; | |
486 | if (class->usage_mask & lock_flag(bit + 2)) | |
487 | c = '?'; | |
fbb9ce95 IM |
488 | } |
489 | ||
3ff176ca PZ |
490 | return c; |
491 | } | |
cf40bd16 | 492 | |
f510b233 | 493 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 494 | { |
f510b233 | 495 | int i = 0; |
cf40bd16 | 496 | |
f510b233 PZ |
497 | #define LOCKDEP_STATE(__STATE) \ |
498 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
499 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
500 | #include "lockdep_states.h" | |
501 | #undef LOCKDEP_STATE | |
502 | ||
503 | usage[i] = '\0'; | |
fbb9ce95 IM |
504 | } |
505 | ||
e5e78d08 | 506 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
507 | { |
508 | char str[KSYM_NAME_LEN]; | |
509 | const char *name; | |
510 | ||
fbb9ce95 IM |
511 | name = class->name; |
512 | if (!name) { | |
513 | name = __get_key_name(class->key, str); | |
f943fe0f | 514 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 515 | } else { |
f943fe0f | 516 | printk(KERN_CONT "%s", name); |
fbb9ce95 | 517 | if (class->name_version > 1) |
f943fe0f | 518 | printk(KERN_CONT "#%d", class->name_version); |
fbb9ce95 | 519 | if (class->subclass) |
f943fe0f | 520 | printk(KERN_CONT "/%d", class->subclass); |
fbb9ce95 | 521 | } |
e5e78d08 SR |
522 | } |
523 | ||
524 | static void print_lock_name(struct lock_class *class) | |
525 | { | |
526 | char usage[LOCK_USAGE_CHARS]; | |
527 | ||
528 | get_usage_chars(class, usage); | |
529 | ||
f943fe0f | 530 | printk(KERN_CONT " ("); |
e5e78d08 | 531 | __print_lock_name(class); |
f943fe0f | 532 | printk(KERN_CONT "){%s}", usage); |
fbb9ce95 IM |
533 | } |
534 | ||
535 | static void print_lockdep_cache(struct lockdep_map *lock) | |
536 | { | |
537 | const char *name; | |
9281acea | 538 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
539 | |
540 | name = lock->name; | |
541 | if (!name) | |
542 | name = __get_key_name(lock->key->subkeys, str); | |
543 | ||
f943fe0f | 544 | printk(KERN_CONT "%s", name); |
fbb9ce95 IM |
545 | } |
546 | ||
547 | static void print_lock(struct held_lock *hlock) | |
548 | { | |
d7bc3197 PZ |
549 | /* |
550 | * We can be called locklessly through debug_show_all_locks() so be | |
551 | * extra careful, the hlock might have been released and cleared. | |
552 | */ | |
553 | unsigned int class_idx = hlock->class_idx; | |
554 | ||
555 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ | |
556 | barrier(); | |
557 | ||
558 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { | |
f943fe0f | 559 | printk(KERN_CONT "<RELEASED>\n"); |
d7bc3197 PZ |
560 | return; |
561 | } | |
562 | ||
563 | print_lock_name(lock_classes + class_idx - 1); | |
f943fe0f DV |
564 | printk(KERN_CONT ", at: [<%p>] %pS\n", |
565 | (void *)hlock->acquire_ip, (void *)hlock->acquire_ip); | |
fbb9ce95 IM |
566 | } |
567 | ||
568 | static void lockdep_print_held_locks(struct task_struct *curr) | |
569 | { | |
570 | int i, depth = curr->lockdep_depth; | |
571 | ||
572 | if (!depth) { | |
ba25f9dc | 573 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
574 | return; |
575 | } | |
576 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 577 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
578 | |
579 | for (i = 0; i < depth; i++) { | |
580 | printk(" #%d: ", i); | |
581 | print_lock(curr->held_locks + i); | |
582 | } | |
583 | } | |
fbb9ce95 | 584 | |
fbdc4b9a | 585 | static void print_kernel_ident(void) |
8e18257d | 586 | { |
fbdc4b9a | 587 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 588 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
589 | init_utsname()->version, |
590 | print_tainted()); | |
8e18257d PZ |
591 | } |
592 | ||
593 | static int very_verbose(struct lock_class *class) | |
594 | { | |
595 | #if VERY_VERBOSE | |
596 | return class_filter(class); | |
597 | #endif | |
598 | return 0; | |
599 | } | |
600 | ||
fbb9ce95 | 601 | /* |
8e18257d | 602 | * Is this the address of a static object: |
fbb9ce95 | 603 | */ |
8dce7a9a | 604 | #ifdef __KERNEL__ |
8e18257d | 605 | static int static_obj(void *obj) |
fbb9ce95 | 606 | { |
8e18257d PZ |
607 | unsigned long start = (unsigned long) &_stext, |
608 | end = (unsigned long) &_end, | |
609 | addr = (unsigned long) obj; | |
8e18257d | 610 | |
fbb9ce95 | 611 | /* |
8e18257d | 612 | * static variable? |
fbb9ce95 | 613 | */ |
8e18257d PZ |
614 | if ((addr >= start) && (addr < end)) |
615 | return 1; | |
fbb9ce95 | 616 | |
2a9ad18d MF |
617 | if (arch_is_kernel_data(addr)) |
618 | return 1; | |
619 | ||
fbb9ce95 | 620 | /* |
10fad5e4 | 621 | * in-kernel percpu var? |
fbb9ce95 | 622 | */ |
10fad5e4 TH |
623 | if (is_kernel_percpu_address(addr)) |
624 | return 1; | |
fbb9ce95 | 625 | |
8e18257d | 626 | /* |
10fad5e4 | 627 | * module static or percpu var? |
8e18257d | 628 | */ |
10fad5e4 | 629 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 630 | } |
8dce7a9a | 631 | #endif |
99de055a | 632 | |
fbb9ce95 | 633 | /* |
8e18257d PZ |
634 | * To make lock name printouts unique, we calculate a unique |
635 | * class->name_version generation counter: | |
fbb9ce95 | 636 | */ |
8e18257d | 637 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 638 | { |
8e18257d PZ |
639 | struct lock_class *class; |
640 | int count = 0; | |
fbb9ce95 | 641 | |
8e18257d | 642 | if (!new_class->name) |
fbb9ce95 IM |
643 | return 0; |
644 | ||
35a9393c | 645 | list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
646 | if (new_class->key - new_class->subclass == class->key) |
647 | return class->name_version; | |
648 | if (class->name && !strcmp(class->name, new_class->name)) | |
649 | count = max(count, class->name_version); | |
650 | } | |
fbb9ce95 | 651 | |
8e18257d | 652 | return count + 1; |
fbb9ce95 IM |
653 | } |
654 | ||
8e18257d PZ |
655 | /* |
656 | * Register a lock's class in the hash-table, if the class is not present | |
657 | * yet. Otherwise we look it up. We cache the result in the lock object | |
658 | * itself, so actual lookup of the hash should be once per lock object. | |
659 | */ | |
660 | static inline struct lock_class * | |
661 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 662 | { |
8e18257d | 663 | struct lockdep_subclass_key *key; |
a63f38cc | 664 | struct hlist_head *hash_head; |
8e18257d | 665 | struct lock_class *class; |
383776fa | 666 | bool is_static = false; |
fbb9ce95 | 667 | |
4ba053c0 HM |
668 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
669 | debug_locks_off(); | |
670 | printk(KERN_ERR | |
671 | "BUG: looking up invalid subclass: %u\n", subclass); | |
672 | printk(KERN_ERR | |
673 | "turning off the locking correctness validator.\n"); | |
674 | dump_stack(); | |
675 | return NULL; | |
676 | } | |
677 | ||
8e18257d PZ |
678 | /* |
679 | * Static locks do not have their class-keys yet - for them the key | |
383776fa TG |
680 | * is the lock object itself. If the lock is in the per cpu area, |
681 | * the canonical address of the lock (per cpu offset removed) is | |
682 | * used. | |
8e18257d | 683 | */ |
383776fa TG |
684 | if (unlikely(!lock->key)) { |
685 | unsigned long can_addr, addr = (unsigned long)lock; | |
686 | ||
687 | if (__is_kernel_percpu_address(addr, &can_addr)) | |
688 | lock->key = (void *)can_addr; | |
689 | else if (__is_module_percpu_address(addr, &can_addr)) | |
690 | lock->key = (void *)can_addr; | |
691 | else if (static_obj(lock)) | |
692 | lock->key = (void *)lock; | |
693 | else | |
694 | return ERR_PTR(-EINVAL); | |
695 | is_static = true; | |
696 | } | |
fbb9ce95 | 697 | |
8e18257d PZ |
698 | /* |
699 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
700 | * lock_class_key variable is passed in through the mutex_init() | |
701 | * (or spin_lock_init()) call - which acts as the key. For static | |
702 | * locks we use the lock object itself as the key. | |
703 | */ | |
4b32d0a4 PZ |
704 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
705 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 706 | |
8e18257d | 707 | key = lock->key->subkeys + subclass; |
ca268c69 | 708 | |
8e18257d | 709 | hash_head = classhashentry(key); |
74c383f1 | 710 | |
8e18257d | 711 | /* |
35a9393c | 712 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 713 | */ |
35a9393c PZ |
714 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
715 | return NULL; | |
716 | ||
a63f38cc | 717 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
4b32d0a4 | 718 | if (class->key == key) { |
0119fee4 PZ |
719 | /* |
720 | * Huh! same key, different name? Did someone trample | |
721 | * on some memory? We're most confused. | |
722 | */ | |
4b32d0a4 | 723 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 724 | return class; |
4b32d0a4 PZ |
725 | } |
726 | } | |
fbb9ce95 | 727 | |
383776fa | 728 | return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL); |
fbb9ce95 IM |
729 | } |
730 | ||
b09be676 BP |
731 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE |
732 | static void cross_init(struct lockdep_map *lock, int cross); | |
733 | static int cross_lock(struct lockdep_map *lock); | |
734 | static int lock_acquire_crosslock(struct held_lock *hlock); | |
735 | static int lock_release_crosslock(struct lockdep_map *lock); | |
736 | #else | |
737 | static inline void cross_init(struct lockdep_map *lock, int cross) {} | |
738 | static inline int cross_lock(struct lockdep_map *lock) { return 0; } | |
739 | static inline int lock_acquire_crosslock(struct held_lock *hlock) { return 2; } | |
740 | static inline int lock_release_crosslock(struct lockdep_map *lock) { return 2; } | |
741 | #endif | |
742 | ||
fbb9ce95 | 743 | /* |
8e18257d PZ |
744 | * Register a lock's class in the hash-table, if the class is not present |
745 | * yet. Otherwise we look it up. We cache the result in the lock object | |
746 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 747 | */ |
c003ed92 | 748 | static struct lock_class * |
8e18257d | 749 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
fbb9ce95 | 750 | { |
8e18257d | 751 | struct lockdep_subclass_key *key; |
a63f38cc | 752 | struct hlist_head *hash_head; |
8e18257d | 753 | struct lock_class *class; |
35a9393c PZ |
754 | |
755 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
756 | |
757 | class = look_up_lock_class(lock, subclass); | |
383776fa | 758 | if (likely(!IS_ERR_OR_NULL(class))) |
87cdee71 | 759 | goto out_set_class_cache; |
8e18257d PZ |
760 | |
761 | /* | |
762 | * Debug-check: all keys must be persistent! | |
383776fa TG |
763 | */ |
764 | if (IS_ERR(class)) { | |
8e18257d PZ |
765 | debug_locks_off(); |
766 | printk("INFO: trying to register non-static key.\n"); | |
767 | printk("the code is fine but needs lockdep annotation.\n"); | |
768 | printk("turning off the locking correctness validator.\n"); | |
769 | dump_stack(); | |
8e18257d PZ |
770 | return NULL; |
771 | } | |
772 | ||
773 | key = lock->key->subkeys + subclass; | |
774 | hash_head = classhashentry(key); | |
775 | ||
8e18257d | 776 | if (!graph_lock()) { |
8e18257d PZ |
777 | return NULL; |
778 | } | |
779 | /* | |
780 | * We have to do the hash-walk again, to avoid races | |
781 | * with another CPU: | |
782 | */ | |
a63f38cc | 783 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
784 | if (class->key == key) |
785 | goto out_unlock_set; | |
35a9393c PZ |
786 | } |
787 | ||
8e18257d PZ |
788 | /* |
789 | * Allocate a new key from the static array, and add it to | |
790 | * the hash: | |
791 | */ | |
792 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
793 | if (!debug_locks_off_graph_unlock()) { | |
8e18257d PZ |
794 | return NULL; |
795 | } | |
8e18257d | 796 | |
2c522836 | 797 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 798 | dump_stack(); |
8e18257d PZ |
799 | return NULL; |
800 | } | |
801 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 802 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
803 | class->key = key; |
804 | class->name = lock->name; | |
805 | class->subclass = subclass; | |
806 | INIT_LIST_HEAD(&class->lock_entry); | |
807 | INIT_LIST_HEAD(&class->locks_before); | |
808 | INIT_LIST_HEAD(&class->locks_after); | |
809 | class->name_version = count_matching_names(class); | |
810 | /* | |
811 | * We use RCU's safe list-add method to make | |
812 | * parallel walking of the hash-list safe: | |
813 | */ | |
a63f38cc | 814 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
1481197b DF |
815 | /* |
816 | * Add it to the global list of classes: | |
817 | */ | |
818 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
819 | |
820 | if (verbose(class)) { | |
821 | graph_unlock(); | |
8e18257d PZ |
822 | |
823 | printk("\nnew class %p: %s", class->key, class->name); | |
824 | if (class->name_version > 1) | |
f943fe0f DV |
825 | printk(KERN_CONT "#%d", class->name_version); |
826 | printk(KERN_CONT "\n"); | |
8e18257d PZ |
827 | dump_stack(); |
828 | ||
8e18257d | 829 | if (!graph_lock()) { |
8e18257d PZ |
830 | return NULL; |
831 | } | |
832 | } | |
833 | out_unlock_set: | |
834 | graph_unlock(); | |
8e18257d | 835 | |
87cdee71 | 836 | out_set_class_cache: |
8e18257d | 837 | if (!subclass || force) |
62016250 HM |
838 | lock->class_cache[0] = class; |
839 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
840 | lock->class_cache[subclass] = class; | |
8e18257d | 841 | |
0119fee4 PZ |
842 | /* |
843 | * Hash collision, did we smoke some? We found a class with a matching | |
844 | * hash but the subclass -- which is hashed in -- didn't match. | |
845 | */ | |
8e18257d PZ |
846 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
847 | return NULL; | |
848 | ||
849 | return class; | |
850 | } | |
851 | ||
852 | #ifdef CONFIG_PROVE_LOCKING | |
853 | /* | |
854 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
855 | * with NULL on failure) | |
856 | */ | |
857 | static struct lock_list *alloc_list_entry(void) | |
858 | { | |
859 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
860 | if (!debug_locks_off_graph_unlock()) | |
861 | return NULL; | |
862 | ||
2c522836 | 863 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 864 | dump_stack(); |
8e18257d PZ |
865 | return NULL; |
866 | } | |
867 | return list_entries + nr_list_entries++; | |
868 | } | |
869 | ||
870 | /* | |
871 | * Add a new dependency to the head of the list: | |
872 | */ | |
83f06168 TE |
873 | static int add_lock_to_list(struct lock_class *this, struct list_head *head, |
874 | unsigned long ip, int distance, | |
875 | struct stack_trace *trace) | |
8e18257d PZ |
876 | { |
877 | struct lock_list *entry; | |
878 | /* | |
879 | * Lock not present yet - get a new dependency struct and | |
880 | * add it to the list: | |
881 | */ | |
882 | entry = alloc_list_entry(); | |
883 | if (!entry) | |
884 | return 0; | |
885 | ||
74870172 ZY |
886 | entry->class = this; |
887 | entry->distance = distance; | |
4726f2a6 | 888 | entry->trace = *trace; |
8e18257d | 889 | /* |
35a9393c PZ |
890 | * Both allocation and removal are done under the graph lock; but |
891 | * iteration is under RCU-sched; see look_up_lock_class() and | |
892 | * lockdep_free_key_range(). | |
8e18257d PZ |
893 | */ |
894 | list_add_tail_rcu(&entry->entry, head); | |
895 | ||
896 | return 1; | |
897 | } | |
898 | ||
98c33edd PZ |
899 | /* |
900 | * For good efficiency of modular, we use power of 2 | |
901 | */ | |
af012961 PZ |
902 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
903 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
904 | ||
98c33edd PZ |
905 | /* |
906 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
907 | * breadth-first search(BFS)algorithem, by which we can build |
908 | * the shortest path from the next lock to be acquired to the | |
909 | * previous held lock if there is a circular between them. | |
98c33edd | 910 | */ |
af012961 PZ |
911 | struct circular_queue { |
912 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
913 | unsigned int front, rear; | |
914 | }; | |
915 | ||
916 | static struct circular_queue lock_cq; | |
af012961 | 917 | |
12f3dfd0 | 918 | unsigned int max_bfs_queue_depth; |
af012961 | 919 | |
e351b660 ML |
920 | static unsigned int lockdep_dependency_gen_id; |
921 | ||
af012961 PZ |
922 | static inline void __cq_init(struct circular_queue *cq) |
923 | { | |
924 | cq->front = cq->rear = 0; | |
e351b660 | 925 | lockdep_dependency_gen_id++; |
af012961 PZ |
926 | } |
927 | ||
928 | static inline int __cq_empty(struct circular_queue *cq) | |
929 | { | |
930 | return (cq->front == cq->rear); | |
931 | } | |
932 | ||
933 | static inline int __cq_full(struct circular_queue *cq) | |
934 | { | |
935 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
936 | } | |
937 | ||
938 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
939 | { | |
940 | if (__cq_full(cq)) | |
941 | return -1; | |
942 | ||
943 | cq->element[cq->rear] = elem; | |
944 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
945 | return 0; | |
946 | } | |
947 | ||
948 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
949 | { | |
950 | if (__cq_empty(cq)) | |
951 | return -1; | |
952 | ||
953 | *elem = cq->element[cq->front]; | |
954 | cq->front = (cq->front + 1) & CQ_MASK; | |
955 | return 0; | |
956 | } | |
957 | ||
958 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
959 | { | |
960 | return (cq->rear - cq->front) & CQ_MASK; | |
961 | } | |
962 | ||
963 | static inline void mark_lock_accessed(struct lock_list *lock, | |
964 | struct lock_list *parent) | |
965 | { | |
966 | unsigned long nr; | |
98c33edd | 967 | |
af012961 | 968 | nr = lock - list_entries; |
0119fee4 | 969 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 970 | lock->parent = parent; |
e351b660 | 971 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
972 | } |
973 | ||
974 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
975 | { | |
976 | unsigned long nr; | |
98c33edd | 977 | |
af012961 | 978 | nr = lock - list_entries; |
0119fee4 | 979 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 980 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
981 | } |
982 | ||
983 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
984 | { | |
985 | return child->parent; | |
986 | } | |
987 | ||
988 | static inline int get_lock_depth(struct lock_list *child) | |
989 | { | |
990 | int depth = 0; | |
991 | struct lock_list *parent; | |
992 | ||
993 | while ((parent = get_lock_parent(child))) { | |
994 | child = parent; | |
995 | depth++; | |
996 | } | |
997 | return depth; | |
998 | } | |
999 | ||
9e2d551e | 1000 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
1001 | void *data, |
1002 | int (*match)(struct lock_list *entry, void *data), | |
1003 | struct lock_list **target_entry, | |
1004 | int forward) | |
c94aa5ca ML |
1005 | { |
1006 | struct lock_list *entry; | |
d588e461 | 1007 | struct list_head *head; |
c94aa5ca ML |
1008 | struct circular_queue *cq = &lock_cq; |
1009 | int ret = 1; | |
1010 | ||
9e2d551e | 1011 | if (match(source_entry, data)) { |
c94aa5ca ML |
1012 | *target_entry = source_entry; |
1013 | ret = 0; | |
1014 | goto exit; | |
1015 | } | |
1016 | ||
d588e461 ML |
1017 | if (forward) |
1018 | head = &source_entry->class->locks_after; | |
1019 | else | |
1020 | head = &source_entry->class->locks_before; | |
1021 | ||
1022 | if (list_empty(head)) | |
1023 | goto exit; | |
1024 | ||
1025 | __cq_init(cq); | |
c94aa5ca ML |
1026 | __cq_enqueue(cq, (unsigned long)source_entry); |
1027 | ||
1028 | while (!__cq_empty(cq)) { | |
1029 | struct lock_list *lock; | |
c94aa5ca ML |
1030 | |
1031 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1032 | ||
1033 | if (!lock->class) { | |
1034 | ret = -2; | |
1035 | goto exit; | |
1036 | } | |
1037 | ||
1038 | if (forward) | |
1039 | head = &lock->class->locks_after; | |
1040 | else | |
1041 | head = &lock->class->locks_before; | |
1042 | ||
35a9393c PZ |
1043 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1044 | ||
1045 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1046 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1047 | unsigned int cq_depth; |
c94aa5ca | 1048 | mark_lock_accessed(entry, lock); |
9e2d551e | 1049 | if (match(entry, data)) { |
c94aa5ca ML |
1050 | *target_entry = entry; |
1051 | ret = 0; | |
1052 | goto exit; | |
1053 | } | |
1054 | ||
1055 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1056 | ret = -1; | |
1057 | goto exit; | |
1058 | } | |
12f3dfd0 ML |
1059 | cq_depth = __cq_get_elem_count(cq); |
1060 | if (max_bfs_queue_depth < cq_depth) | |
1061 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1062 | } |
1063 | } | |
1064 | } | |
1065 | exit: | |
1066 | return ret; | |
1067 | } | |
1068 | ||
d7aaba14 | 1069 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1070 | void *data, |
1071 | int (*match)(struct lock_list *entry, void *data), | |
1072 | struct lock_list **target_entry) | |
c94aa5ca | 1073 | { |
9e2d551e | 1074 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1075 | |
1076 | } | |
1077 | ||
d7aaba14 | 1078 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1079 | void *data, |
1080 | int (*match)(struct lock_list *entry, void *data), | |
1081 | struct lock_list **target_entry) | |
c94aa5ca | 1082 | { |
9e2d551e | 1083 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1084 | |
1085 | } | |
1086 | ||
8e18257d PZ |
1087 | /* |
1088 | * Recursive, forwards-direction lock-dependency checking, used for | |
1089 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1090 | * checking. | |
8e18257d | 1091 | */ |
8e18257d PZ |
1092 | |
1093 | /* | |
1094 | * Print a dependency chain entry (this is only done when a deadlock | |
1095 | * has been detected): | |
1096 | */ | |
1097 | static noinline int | |
24208ca7 | 1098 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1099 | { |
1100 | if (debug_locks_silent) | |
1101 | return 0; | |
1102 | printk("\n-> #%u", depth); | |
1103 | print_lock_name(target->class); | |
f943fe0f | 1104 | printk(KERN_CONT ":\n"); |
8e18257d PZ |
1105 | print_stack_trace(&target->trace, 6); |
1106 | ||
1107 | return 0; | |
1108 | } | |
1109 | ||
f4185812 SR |
1110 | static void |
1111 | print_circular_lock_scenario(struct held_lock *src, | |
1112 | struct held_lock *tgt, | |
1113 | struct lock_list *prt) | |
1114 | { | |
1115 | struct lock_class *source = hlock_class(src); | |
1116 | struct lock_class *target = hlock_class(tgt); | |
1117 | struct lock_class *parent = prt->class; | |
1118 | ||
1119 | /* | |
1120 | * A direct locking problem where unsafe_class lock is taken | |
1121 | * directly by safe_class lock, then all we need to show | |
1122 | * is the deadlock scenario, as it is obvious that the | |
1123 | * unsafe lock is taken under the safe lock. | |
1124 | * | |
1125 | * But if there is a chain instead, where the safe lock takes | |
1126 | * an intermediate lock (middle_class) where this lock is | |
1127 | * not the same as the safe lock, then the lock chain is | |
1128 | * used to describe the problem. Otherwise we would need | |
1129 | * to show a different CPU case for each link in the chain | |
1130 | * from the safe_class lock to the unsafe_class lock. | |
1131 | */ | |
1132 | if (parent != source) { | |
1133 | printk("Chain exists of:\n "); | |
1134 | __print_lock_name(source); | |
f943fe0f | 1135 | printk(KERN_CONT " --> "); |
f4185812 | 1136 | __print_lock_name(parent); |
f943fe0f | 1137 | printk(KERN_CONT " --> "); |
f4185812 | 1138 | __print_lock_name(target); |
f943fe0f | 1139 | printk(KERN_CONT "\n\n"); |
f4185812 SR |
1140 | } |
1141 | ||
383a4bc8 BP |
1142 | if (cross_lock(tgt->instance)) { |
1143 | printk(" Possible unsafe locking scenario by crosslock:\n\n"); | |
1144 | printk(" CPU0 CPU1\n"); | |
1145 | printk(" ---- ----\n"); | |
1146 | printk(" lock("); | |
1147 | __print_lock_name(parent); | |
1148 | printk(KERN_CONT ");\n"); | |
1149 | printk(" lock("); | |
1150 | __print_lock_name(target); | |
1151 | printk(KERN_CONT ");\n"); | |
1152 | printk(" lock("); | |
1153 | __print_lock_name(source); | |
1154 | printk(KERN_CONT ");\n"); | |
1155 | printk(" unlock("); | |
1156 | __print_lock_name(target); | |
1157 | printk(KERN_CONT ");\n"); | |
1158 | printk("\n *** DEADLOCK ***\n\n"); | |
1159 | } else { | |
1160 | printk(" Possible unsafe locking scenario:\n\n"); | |
1161 | printk(" CPU0 CPU1\n"); | |
1162 | printk(" ---- ----\n"); | |
1163 | printk(" lock("); | |
1164 | __print_lock_name(target); | |
1165 | printk(KERN_CONT ");\n"); | |
1166 | printk(" lock("); | |
1167 | __print_lock_name(parent); | |
1168 | printk(KERN_CONT ");\n"); | |
1169 | printk(" lock("); | |
1170 | __print_lock_name(target); | |
1171 | printk(KERN_CONT ");\n"); | |
1172 | printk(" lock("); | |
1173 | __print_lock_name(source); | |
1174 | printk(KERN_CONT ");\n"); | |
1175 | printk("\n *** DEADLOCK ***\n\n"); | |
1176 | } | |
f4185812 SR |
1177 | } |
1178 | ||
8e18257d PZ |
1179 | /* |
1180 | * When a circular dependency is detected, print the | |
1181 | * header first: | |
1182 | */ | |
1183 | static noinline int | |
db0002a3 ML |
1184 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1185 | struct held_lock *check_src, | |
1186 | struct held_lock *check_tgt) | |
8e18257d PZ |
1187 | { |
1188 | struct task_struct *curr = current; | |
1189 | ||
c94aa5ca | 1190 | if (debug_locks_silent) |
8e18257d PZ |
1191 | return 0; |
1192 | ||
681fbec8 | 1193 | pr_warn("\n"); |
a5dd63ef PM |
1194 | pr_warn("======================================================\n"); |
1195 | pr_warn("WARNING: possible circular locking dependency detected\n"); | |
fbdc4b9a | 1196 | print_kernel_ident(); |
a5dd63ef | 1197 | pr_warn("------------------------------------------------------\n"); |
681fbec8 | 1198 | pr_warn("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1199 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1200 | print_lock(check_src); |
383a4bc8 BP |
1201 | |
1202 | if (cross_lock(check_tgt->instance)) | |
1203 | pr_warn("\nbut now in release context of a crosslock acquired at the following:\n"); | |
1204 | else | |
1205 | pr_warn("\nbut task is already holding lock:\n"); | |
1206 | ||
db0002a3 | 1207 | print_lock(check_tgt); |
681fbec8 PM |
1208 | pr_warn("\nwhich lock already depends on the new lock.\n\n"); |
1209 | pr_warn("\nthe existing dependency chain (in reverse order) is:\n"); | |
8e18257d PZ |
1210 | |
1211 | print_circular_bug_entry(entry, depth); | |
1212 | ||
1213 | return 0; | |
1214 | } | |
1215 | ||
9e2d551e ML |
1216 | static inline int class_equal(struct lock_list *entry, void *data) |
1217 | { | |
1218 | return entry->class == data; | |
1219 | } | |
1220 | ||
db0002a3 ML |
1221 | static noinline int print_circular_bug(struct lock_list *this, |
1222 | struct lock_list *target, | |
1223 | struct held_lock *check_src, | |
383a4bc8 BP |
1224 | struct held_lock *check_tgt, |
1225 | struct stack_trace *trace) | |
8e18257d PZ |
1226 | { |
1227 | struct task_struct *curr = current; | |
c94aa5ca | 1228 | struct lock_list *parent; |
f4185812 | 1229 | struct lock_list *first_parent; |
24208ca7 | 1230 | int depth; |
8e18257d | 1231 | |
c94aa5ca | 1232 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1233 | return 0; |
1234 | ||
383a4bc8 BP |
1235 | if (cross_lock(check_tgt->instance)) |
1236 | this->trace = *trace; | |
1237 | else if (!save_trace(&this->trace)) | |
8e18257d PZ |
1238 | return 0; |
1239 | ||
c94aa5ca ML |
1240 | depth = get_lock_depth(target); |
1241 | ||
db0002a3 | 1242 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1243 | |
1244 | parent = get_lock_parent(target); | |
f4185812 | 1245 | first_parent = parent; |
c94aa5ca ML |
1246 | |
1247 | while (parent) { | |
1248 | print_circular_bug_entry(parent, --depth); | |
1249 | parent = get_lock_parent(parent); | |
1250 | } | |
8e18257d PZ |
1251 | |
1252 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1253 | print_circular_lock_scenario(check_src, check_tgt, |
1254 | first_parent); | |
1255 | ||
8e18257d PZ |
1256 | lockdep_print_held_locks(curr); |
1257 | ||
1258 | printk("\nstack backtrace:\n"); | |
1259 | dump_stack(); | |
1260 | ||
1261 | return 0; | |
1262 | } | |
1263 | ||
db0002a3 ML |
1264 | static noinline int print_bfs_bug(int ret) |
1265 | { | |
1266 | if (!debug_locks_off_graph_unlock()) | |
1267 | return 0; | |
1268 | ||
0119fee4 PZ |
1269 | /* |
1270 | * Breadth-first-search failed, graph got corrupted? | |
1271 | */ | |
db0002a3 ML |
1272 | WARN(1, "lockdep bfs error:%d\n", ret); |
1273 | ||
1274 | return 0; | |
1275 | } | |
1276 | ||
ef681026 | 1277 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1278 | { |
ef681026 ML |
1279 | (*(unsigned long *)data)++; |
1280 | return 0; | |
1281 | } | |
419ca3f1 | 1282 | |
5216d530 | 1283 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1284 | { |
1285 | unsigned long count = 0; | |
1286 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1287 | |
ef681026 | 1288 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1289 | |
ef681026 | 1290 | return count; |
419ca3f1 | 1291 | } |
419ca3f1 DM |
1292 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1293 | { | |
1294 | unsigned long ret, flags; | |
ef681026 ML |
1295 | struct lock_list this; |
1296 | ||
1297 | this.parent = NULL; | |
1298 | this.class = class; | |
419ca3f1 DM |
1299 | |
1300 | local_irq_save(flags); | |
0199c4e6 | 1301 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1302 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1303 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1304 | local_irq_restore(flags); |
1305 | ||
1306 | return ret; | |
1307 | } | |
1308 | ||
5216d530 | 1309 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1310 | { |
ef681026 ML |
1311 | unsigned long count = 0; |
1312 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1313 | |
ef681026 | 1314 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1315 | |
ef681026 | 1316 | return count; |
419ca3f1 DM |
1317 | } |
1318 | ||
1319 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1320 | { | |
1321 | unsigned long ret, flags; | |
ef681026 ML |
1322 | struct lock_list this; |
1323 | ||
1324 | this.parent = NULL; | |
1325 | this.class = class; | |
419ca3f1 DM |
1326 | |
1327 | local_irq_save(flags); | |
0199c4e6 | 1328 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1329 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1330 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1331 | local_irq_restore(flags); |
1332 | ||
1333 | return ret; | |
1334 | } | |
1335 | ||
8e18257d PZ |
1336 | /* |
1337 | * Prove that the dependency graph starting at <entry> can not | |
1338 | * lead to <target>. Print an error and return 0 if it does. | |
1339 | */ | |
1340 | static noinline int | |
db0002a3 ML |
1341 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1342 | struct lock_list **target_entry) | |
8e18257d | 1343 | { |
db0002a3 | 1344 | int result; |
8e18257d | 1345 | |
bd6d29c2 | 1346 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1347 | |
d7aaba14 | 1348 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1349 | |
db0002a3 ML |
1350 | return result; |
1351 | } | |
c94aa5ca | 1352 | |
ae813308 PZ |
1353 | static noinline int |
1354 | check_redundant(struct lock_list *root, struct lock_class *target, | |
1355 | struct lock_list **target_entry) | |
1356 | { | |
1357 | int result; | |
1358 | ||
1359 | debug_atomic_inc(nr_redundant_checks); | |
1360 | ||
1361 | result = __bfs_forwards(root, target, class_equal, target_entry); | |
1362 | ||
1363 | return result; | |
1364 | } | |
1365 | ||
81d68a96 | 1366 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1367 | /* |
1368 | * Forwards and backwards subgraph searching, for the purposes of | |
1369 | * proving that two subgraphs can be connected by a new dependency | |
1370 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1371 | */ | |
fbb9ce95 | 1372 | |
d7aaba14 ML |
1373 | static inline int usage_match(struct lock_list *entry, void *bit) |
1374 | { | |
1375 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1376 | } | |
1377 | ||
1378 | ||
1379 | ||
fbb9ce95 IM |
1380 | /* |
1381 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1382 | * at @root->class that matches @bit. |
fbb9ce95 | 1383 | * |
d7aaba14 ML |
1384 | * Return 0 if such a node exists in the subgraph, and put that node |
1385 | * into *@target_entry. | |
fbb9ce95 | 1386 | * |
d7aaba14 ML |
1387 | * Return 1 otherwise and keep *@target_entry unchanged. |
1388 | * Return <0 on error. | |
fbb9ce95 | 1389 | */ |
d7aaba14 ML |
1390 | static int |
1391 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1392 | struct lock_list **target_entry) | |
fbb9ce95 | 1393 | { |
d7aaba14 | 1394 | int result; |
fbb9ce95 | 1395 | |
bd6d29c2 | 1396 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1397 | |
d7aaba14 ML |
1398 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1399 | ||
1400 | return result; | |
fbb9ce95 IM |
1401 | } |
1402 | ||
1403 | /* | |
1404 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1405 | * at @root->class that matches @bit. |
fbb9ce95 | 1406 | * |
d7aaba14 ML |
1407 | * Return 0 if such a node exists in the subgraph, and put that node |
1408 | * into *@target_entry. | |
fbb9ce95 | 1409 | * |
d7aaba14 ML |
1410 | * Return 1 otherwise and keep *@target_entry unchanged. |
1411 | * Return <0 on error. | |
fbb9ce95 | 1412 | */ |
d7aaba14 ML |
1413 | static int |
1414 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1415 | struct lock_list **target_entry) | |
fbb9ce95 | 1416 | { |
d7aaba14 | 1417 | int result; |
fbb9ce95 | 1418 | |
bd6d29c2 | 1419 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1420 | |
d7aaba14 | 1421 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1422 | |
d7aaba14 | 1423 | return result; |
fbb9ce95 IM |
1424 | } |
1425 | ||
af012961 PZ |
1426 | static void print_lock_class_header(struct lock_class *class, int depth) |
1427 | { | |
1428 | int bit; | |
1429 | ||
1430 | printk("%*s->", depth, ""); | |
1431 | print_lock_name(class); | |
f943fe0f DV |
1432 | printk(KERN_CONT " ops: %lu", class->ops); |
1433 | printk(KERN_CONT " {\n"); | |
af012961 PZ |
1434 | |
1435 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1436 | if (class->usage_mask & (1 << bit)) { | |
1437 | int len = depth; | |
1438 | ||
1439 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
f943fe0f | 1440 | len += printk(KERN_CONT " at:\n"); |
af012961 PZ |
1441 | print_stack_trace(class->usage_traces + bit, len); |
1442 | } | |
1443 | } | |
1444 | printk("%*s }\n", depth, ""); | |
1445 | ||
f943fe0f DV |
1446 | printk("%*s ... key at: [<%p>] %pS\n", |
1447 | depth, "", class->key, class->key); | |
af012961 PZ |
1448 | } |
1449 | ||
1450 | /* | |
1451 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1452 | */ | |
1453 | static void __used | |
1454 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1455 | struct lock_list *root) | |
1456 | { | |
1457 | struct lock_list *entry = leaf; | |
1458 | int depth; | |
1459 | ||
1460 | /*compute depth from generated tree by BFS*/ | |
1461 | depth = get_lock_depth(leaf); | |
1462 | ||
1463 | do { | |
1464 | print_lock_class_header(entry->class, depth); | |
1465 | printk("%*s ... acquired at:\n", depth, ""); | |
1466 | print_stack_trace(&entry->trace, 2); | |
1467 | printk("\n"); | |
1468 | ||
1469 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1470 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1471 | break; |
1472 | } | |
1473 | ||
1474 | entry = get_lock_parent(entry); | |
1475 | depth--; | |
1476 | } while (entry && (depth >= 0)); | |
1477 | ||
1478 | return; | |
1479 | } | |
d7aaba14 | 1480 | |
3003eba3 SR |
1481 | static void |
1482 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1483 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1484 | struct lock_class *prev_class, |
1485 | struct lock_class *next_class) | |
3003eba3 SR |
1486 | { |
1487 | struct lock_class *safe_class = safe_entry->class; | |
1488 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1489 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1490 | |
1491 | if (middle_class == safe_class) | |
dad3d743 | 1492 | middle_class = next_class; |
3003eba3 SR |
1493 | |
1494 | /* | |
1495 | * A direct locking problem where unsafe_class lock is taken | |
1496 | * directly by safe_class lock, then all we need to show | |
1497 | * is the deadlock scenario, as it is obvious that the | |
1498 | * unsafe lock is taken under the safe lock. | |
1499 | * | |
1500 | * But if there is a chain instead, where the safe lock takes | |
1501 | * an intermediate lock (middle_class) where this lock is | |
1502 | * not the same as the safe lock, then the lock chain is | |
1503 | * used to describe the problem. Otherwise we would need | |
1504 | * to show a different CPU case for each link in the chain | |
1505 | * from the safe_class lock to the unsafe_class lock. | |
1506 | */ | |
1507 | if (middle_class != unsafe_class) { | |
1508 | printk("Chain exists of:\n "); | |
1509 | __print_lock_name(safe_class); | |
f943fe0f | 1510 | printk(KERN_CONT " --> "); |
3003eba3 | 1511 | __print_lock_name(middle_class); |
f943fe0f | 1512 | printk(KERN_CONT " --> "); |
3003eba3 | 1513 | __print_lock_name(unsafe_class); |
f943fe0f | 1514 | printk(KERN_CONT "\n\n"); |
3003eba3 SR |
1515 | } |
1516 | ||
1517 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1518 | printk(" CPU0 CPU1\n"); | |
1519 | printk(" ---- ----\n"); | |
1520 | printk(" lock("); | |
1521 | __print_lock_name(unsafe_class); | |
f943fe0f | 1522 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1523 | printk(" local_irq_disable();\n"); |
1524 | printk(" lock("); | |
1525 | __print_lock_name(safe_class); | |
f943fe0f | 1526 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1527 | printk(" lock("); |
1528 | __print_lock_name(middle_class); | |
f943fe0f | 1529 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1530 | printk(" <Interrupt>\n"); |
1531 | printk(" lock("); | |
1532 | __print_lock_name(safe_class); | |
f943fe0f | 1533 | printk(KERN_CONT ");\n"); |
3003eba3 SR |
1534 | printk("\n *** DEADLOCK ***\n\n"); |
1535 | } | |
1536 | ||
fbb9ce95 IM |
1537 | static int |
1538 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1539 | struct lock_list *prev_root, |
1540 | struct lock_list *next_root, | |
1541 | struct lock_list *backwards_entry, | |
1542 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1543 | struct held_lock *prev, |
1544 | struct held_lock *next, | |
1545 | enum lock_usage_bit bit1, | |
1546 | enum lock_usage_bit bit2, | |
1547 | const char *irqclass) | |
1548 | { | |
74c383f1 | 1549 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1550 | return 0; |
1551 | ||
681fbec8 | 1552 | pr_warn("\n"); |
a5dd63ef PM |
1553 | pr_warn("=====================================================\n"); |
1554 | pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n", | |
fbb9ce95 | 1555 | irqclass, irqclass); |
fbdc4b9a | 1556 | print_kernel_ident(); |
a5dd63ef | 1557 | pr_warn("-----------------------------------------------------\n"); |
681fbec8 | 1558 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1559 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1560 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1561 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1562 | curr->hardirqs_enabled, | |
1563 | curr->softirqs_enabled); | |
1564 | print_lock(next); | |
1565 | ||
681fbec8 | 1566 | pr_warn("\nand this task is already holding:\n"); |
fbb9ce95 | 1567 | print_lock(prev); |
681fbec8 | 1568 | pr_warn("which would create a new lock dependency:\n"); |
f82b217e | 1569 | print_lock_name(hlock_class(prev)); |
681fbec8 | 1570 | pr_cont(" ->"); |
f82b217e | 1571 | print_lock_name(hlock_class(next)); |
681fbec8 | 1572 | pr_cont("\n"); |
fbb9ce95 | 1573 | |
681fbec8 | 1574 | pr_warn("\nbut this new dependency connects a %s-irq-safe lock:\n", |
fbb9ce95 | 1575 | irqclass); |
24208ca7 | 1576 | print_lock_name(backwards_entry->class); |
681fbec8 | 1577 | pr_warn("\n... which became %s-irq-safe at:\n", irqclass); |
fbb9ce95 | 1578 | |
24208ca7 | 1579 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 | 1580 | |
681fbec8 | 1581 | pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass); |
24208ca7 | 1582 | print_lock_name(forwards_entry->class); |
681fbec8 PM |
1583 | pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass); |
1584 | pr_warn("..."); | |
fbb9ce95 | 1585 | |
24208ca7 | 1586 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 | 1587 | |
681fbec8 | 1588 | pr_warn("\nother info that might help us debug this:\n\n"); |
dad3d743 SR |
1589 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1590 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1591 | |
fbb9ce95 IM |
1592 | lockdep_print_held_locks(curr); |
1593 | ||
681fbec8 | 1594 | pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass); |
24208ca7 ML |
1595 | if (!save_trace(&prev_root->trace)) |
1596 | return 0; | |
1597 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1598 | |
681fbec8 PM |
1599 | pr_warn("\nthe dependencies between the lock to be acquired"); |
1600 | pr_warn(" and %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 ML |
1601 | if (!save_trace(&next_root->trace)) |
1602 | return 0; | |
1603 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 | 1604 | |
681fbec8 | 1605 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
1606 | dump_stack(); |
1607 | ||
1608 | return 0; | |
1609 | } | |
1610 | ||
1611 | static int | |
1612 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1613 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1614 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1615 | { | |
1616 | int ret; | |
24208ca7 | 1617 | struct lock_list this, that; |
d7aaba14 | 1618 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1619 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1620 | |
1621 | this.parent = NULL; | |
1622 | ||
1623 | this.class = hlock_class(prev); | |
1624 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1625 | if (ret < 0) |
1626 | return print_bfs_bug(ret); | |
1627 | if (ret == 1) | |
1628 | return ret; | |
d7aaba14 | 1629 | |
24208ca7 ML |
1630 | that.parent = NULL; |
1631 | that.class = hlock_class(next); | |
1632 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1633 | if (ret < 0) |
1634 | return print_bfs_bug(ret); | |
1635 | if (ret == 1) | |
1636 | return ret; | |
fbb9ce95 | 1637 | |
24208ca7 ML |
1638 | return print_bad_irq_dependency(curr, &this, &that, |
1639 | target_entry, target_entry1, | |
1640 | prev, next, | |
fbb9ce95 IM |
1641 | bit_backwards, bit_forwards, irqclass); |
1642 | } | |
1643 | ||
4f367d8a PZ |
1644 | static const char *state_names[] = { |
1645 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1646 | __stringify(__STATE), |
4f367d8a PZ |
1647 | #include "lockdep_states.h" |
1648 | #undef LOCKDEP_STATE | |
1649 | }; | |
1650 | ||
1651 | static const char *state_rnames[] = { | |
1652 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1653 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1654 | #include "lockdep_states.h" |
1655 | #undef LOCKDEP_STATE | |
1656 | }; | |
1657 | ||
1658 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1659 | { |
4f367d8a PZ |
1660 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1661 | } | |
8e18257d | 1662 | |
4f367d8a PZ |
1663 | static int exclusive_bit(int new_bit) |
1664 | { | |
8e18257d | 1665 | /* |
4f367d8a PZ |
1666 | * USED_IN |
1667 | * USED_IN_READ | |
1668 | * ENABLED | |
1669 | * ENABLED_READ | |
1670 | * | |
1671 | * bit 0 - write/read | |
1672 | * bit 1 - used_in/enabled | |
1673 | * bit 2+ state | |
8e18257d | 1674 | */ |
4f367d8a PZ |
1675 | |
1676 | int state = new_bit & ~3; | |
1677 | int dir = new_bit & 2; | |
8e18257d PZ |
1678 | |
1679 | /* | |
4f367d8a | 1680 | * keep state, bit flip the direction and strip read. |
8e18257d | 1681 | */ |
4f367d8a PZ |
1682 | return state | (dir ^ 2); |
1683 | } | |
1684 | ||
1685 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1686 | struct held_lock *next, enum lock_usage_bit bit) | |
1687 | { | |
8e18257d | 1688 | /* |
4f367d8a PZ |
1689 | * Prove that the new dependency does not connect a hardirq-safe |
1690 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1691 | * the backwards-subgraph starting at <prev>, and the |
1692 | * forwards-subgraph starting at <next>: | |
1693 | */ | |
4f367d8a PZ |
1694 | if (!check_usage(curr, prev, next, bit, |
1695 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1696 | return 0; |
1697 | ||
4f367d8a PZ |
1698 | bit++; /* _READ */ |
1699 | ||
cf40bd16 | 1700 | /* |
4f367d8a PZ |
1701 | * Prove that the new dependency does not connect a hardirq-safe-read |
1702 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1703 | * the backwards-subgraph starting at <prev>, and the |
1704 | * forwards-subgraph starting at <next>: | |
1705 | */ | |
4f367d8a PZ |
1706 | if (!check_usage(curr, prev, next, bit, |
1707 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1708 | return 0; |
1709 | ||
4f367d8a PZ |
1710 | return 1; |
1711 | } | |
1712 | ||
1713 | static int | |
1714 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1715 | struct held_lock *next) | |
1716 | { | |
1717 | #define LOCKDEP_STATE(__STATE) \ | |
1718 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1719 | return 0; |
4f367d8a PZ |
1720 | #include "lockdep_states.h" |
1721 | #undef LOCKDEP_STATE | |
cf40bd16 | 1722 | |
8e18257d PZ |
1723 | return 1; |
1724 | } | |
1725 | ||
1726 | static void inc_chains(void) | |
1727 | { | |
1728 | if (current->hardirq_context) | |
1729 | nr_hardirq_chains++; | |
1730 | else { | |
1731 | if (current->softirq_context) | |
1732 | nr_softirq_chains++; | |
1733 | else | |
1734 | nr_process_chains++; | |
1735 | } | |
1736 | } | |
1737 | ||
1738 | #else | |
1739 | ||
1740 | static inline int | |
1741 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1742 | struct held_lock *next) | |
1743 | { | |
1744 | return 1; | |
1745 | } | |
1746 | ||
1747 | static inline void inc_chains(void) | |
1748 | { | |
1749 | nr_process_chains++; | |
1750 | } | |
1751 | ||
fbb9ce95 IM |
1752 | #endif |
1753 | ||
48702ecf SR |
1754 | static void |
1755 | print_deadlock_scenario(struct held_lock *nxt, | |
1756 | struct held_lock *prv) | |
1757 | { | |
1758 | struct lock_class *next = hlock_class(nxt); | |
1759 | struct lock_class *prev = hlock_class(prv); | |
1760 | ||
1761 | printk(" Possible unsafe locking scenario:\n\n"); | |
1762 | printk(" CPU0\n"); | |
1763 | printk(" ----\n"); | |
1764 | printk(" lock("); | |
1765 | __print_lock_name(prev); | |
f943fe0f | 1766 | printk(KERN_CONT ");\n"); |
48702ecf SR |
1767 | printk(" lock("); |
1768 | __print_lock_name(next); | |
f943fe0f | 1769 | printk(KERN_CONT ");\n"); |
48702ecf SR |
1770 | printk("\n *** DEADLOCK ***\n\n"); |
1771 | printk(" May be due to missing lock nesting notation\n\n"); | |
1772 | } | |
1773 | ||
fbb9ce95 IM |
1774 | static int |
1775 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1776 | struct held_lock *next) | |
1777 | { | |
74c383f1 | 1778 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1779 | return 0; |
1780 | ||
681fbec8 | 1781 | pr_warn("\n"); |
a5dd63ef PM |
1782 | pr_warn("============================================\n"); |
1783 | pr_warn("WARNING: possible recursive locking detected\n"); | |
fbdc4b9a | 1784 | print_kernel_ident(); |
a5dd63ef | 1785 | pr_warn("--------------------------------------------\n"); |
681fbec8 | 1786 | pr_warn("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1787 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 1788 | print_lock(next); |
681fbec8 | 1789 | pr_warn("\nbut task is already holding lock:\n"); |
fbb9ce95 IM |
1790 | print_lock(prev); |
1791 | ||
681fbec8 | 1792 | pr_warn("\nother info that might help us debug this:\n"); |
48702ecf | 1793 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1794 | lockdep_print_held_locks(curr); |
1795 | ||
681fbec8 | 1796 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
1797 | dump_stack(); |
1798 | ||
1799 | return 0; | |
1800 | } | |
1801 | ||
1802 | /* | |
1803 | * Check whether we are holding such a class already. | |
1804 | * | |
1805 | * (Note that this has to be done separately, because the graph cannot | |
1806 | * detect such classes of deadlocks.) | |
1807 | * | |
1808 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1809 | */ | |
1810 | static int | |
1811 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1812 | struct lockdep_map *next_instance, int read) | |
1813 | { | |
1814 | struct held_lock *prev; | |
7531e2f3 | 1815 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1816 | int i; |
1817 | ||
1818 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1819 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1820 | |
1821 | if (prev->instance == next->nest_lock) | |
1822 | nest = prev; | |
1823 | ||
f82b217e | 1824 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1825 | continue; |
7531e2f3 | 1826 | |
fbb9ce95 IM |
1827 | /* |
1828 | * Allow read-after-read recursion of the same | |
6c9076ec | 1829 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1830 | */ |
6c9076ec | 1831 | if ((read == 2) && prev->read) |
fbb9ce95 | 1832 | return 2; |
7531e2f3 PZ |
1833 | |
1834 | /* | |
1835 | * We're holding the nest_lock, which serializes this lock's | |
1836 | * nesting behaviour. | |
1837 | */ | |
1838 | if (nest) | |
1839 | return 2; | |
1840 | ||
b09be676 BP |
1841 | if (cross_lock(prev->instance)) |
1842 | continue; | |
1843 | ||
fbb9ce95 IM |
1844 | return print_deadlock_bug(curr, prev, next); |
1845 | } | |
1846 | return 1; | |
1847 | } | |
1848 | ||
1849 | /* | |
1850 | * There was a chain-cache miss, and we are about to add a new dependency | |
1851 | * to a previous lock. We recursively validate the following rules: | |
1852 | * | |
1853 | * - would the adding of the <prev> -> <next> dependency create a | |
1854 | * circular dependency in the graph? [== circular deadlock] | |
1855 | * | |
1856 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1857 | * (in the full backwards-subgraph starting at <prev>) with any | |
1858 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1859 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1860 | * | |
1861 | * - does the new prev->next dependency connect any softirq-safe lock | |
1862 | * (in the full backwards-subgraph starting at <prev>) with any | |
1863 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1864 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1865 | * | |
1866 | * any of these scenarios could lead to a deadlock. | |
1867 | * | |
1868 | * Then if all the validations pass, we add the forwards and backwards | |
1869 | * dependency. | |
1870 | */ | |
1871 | static int | |
1872 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
ce07a941 BP |
1873 | struct held_lock *next, int distance, struct stack_trace *trace, |
1874 | int (*save)(struct stack_trace *trace)) | |
fbb9ce95 IM |
1875 | { |
1876 | struct lock_list *entry; | |
1877 | int ret; | |
db0002a3 ML |
1878 | struct lock_list this; |
1879 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 IM |
1880 | |
1881 | /* | |
1882 | * Prove that the new <prev> -> <next> dependency would not | |
1883 | * create a circular dependency in the graph. (We do this by | |
1884 | * forward-recursing into the graph starting at <next>, and | |
1885 | * checking whether we can reach <prev>.) | |
1886 | * | |
1887 | * We are using global variables to control the recursion, to | |
1888 | * keep the stackframe size of the recursive functions low: | |
1889 | */ | |
db0002a3 ML |
1890 | this.class = hlock_class(next); |
1891 | this.parent = NULL; | |
1892 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1893 | if (unlikely(!ret)) | |
383a4bc8 | 1894 | return print_circular_bug(&this, target_entry, next, prev, trace); |
db0002a3 ML |
1895 | else if (unlikely(ret < 0)) |
1896 | return print_bfs_bug(ret); | |
c94aa5ca | 1897 | |
8e18257d | 1898 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1899 | return 0; |
1900 | ||
fbb9ce95 IM |
1901 | /* |
1902 | * For recursive read-locks we do all the dependency checks, | |
1903 | * but we dont store read-triggered dependencies (only | |
1904 | * write-triggered dependencies). This ensures that only the | |
1905 | * write-side dependencies matter, and that if for example a | |
1906 | * write-lock never takes any other locks, then the reads are | |
1907 | * equivalent to a NOP. | |
1908 | */ | |
1909 | if (next->read == 2 || prev->read == 2) | |
1910 | return 1; | |
1911 | /* | |
1912 | * Is the <prev> -> <next> dependency already present? | |
1913 | * | |
1914 | * (this may occur even though this is a new chain: consider | |
1915 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1916 | * chains - the second one will be new, but L1 already has | |
1917 | * L2 added to its dependency list, due to the first chain.) | |
1918 | */ | |
f82b217e DJ |
1919 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1920 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1921 | if (distance == 1) |
1922 | entry->distance = 1; | |
70911fdc | 1923 | return 1; |
068135e6 | 1924 | } |
fbb9ce95 IM |
1925 | } |
1926 | ||
ae813308 PZ |
1927 | /* |
1928 | * Is the <prev> -> <next> link redundant? | |
1929 | */ | |
1930 | this.class = hlock_class(prev); | |
1931 | this.parent = NULL; | |
1932 | ret = check_redundant(&this, hlock_class(next), &target_entry); | |
1933 | if (!ret) { | |
1934 | debug_atomic_inc(nr_redundant); | |
1935 | return 2; | |
1936 | } | |
1937 | if (ret < 0) | |
1938 | return print_bfs_bug(ret); | |
1939 | ||
1940 | ||
ce07a941 BP |
1941 | if (save && !save(trace)) |
1942 | return 0; | |
4726f2a6 | 1943 | |
fbb9ce95 IM |
1944 | /* |
1945 | * Ok, all validations passed, add the new lock | |
1946 | * to the previous lock's dependency list: | |
1947 | */ | |
83f06168 | 1948 | ret = add_lock_to_list(hlock_class(next), |
f82b217e | 1949 | &hlock_class(prev)->locks_after, |
ce07a941 | 1950 | next->acquire_ip, distance, trace); |
068135e6 | 1951 | |
fbb9ce95 IM |
1952 | if (!ret) |
1953 | return 0; | |
910b1b2e | 1954 | |
83f06168 | 1955 | ret = add_lock_to_list(hlock_class(prev), |
f82b217e | 1956 | &hlock_class(next)->locks_before, |
ce07a941 | 1957 | next->acquire_ip, distance, trace); |
910b1b2e JP |
1958 | if (!ret) |
1959 | return 0; | |
fbb9ce95 IM |
1960 | |
1961 | /* | |
8e18257d PZ |
1962 | * Debugging printouts: |
1963 | */ | |
f82b217e | 1964 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1965 | graph_unlock(); |
1966 | printk("\n new dependency: "); | |
f82b217e | 1967 | print_lock_name(hlock_class(prev)); |
f943fe0f | 1968 | printk(KERN_CONT " => "); |
f82b217e | 1969 | print_lock_name(hlock_class(next)); |
f943fe0f | 1970 | printk(KERN_CONT "\n"); |
fbb9ce95 | 1971 | dump_stack(); |
70911fdc BP |
1972 | if (!graph_lock()) |
1973 | return 0; | |
fbb9ce95 | 1974 | } |
70911fdc | 1975 | return 2; |
8e18257d | 1976 | } |
fbb9ce95 | 1977 | |
8e18257d PZ |
1978 | /* |
1979 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1980 | * The ones that are relevant are (in increasing distance from curr): | |
1981 | * all consecutive trylock entries and the final non-trylock entry - or | |
1982 | * the end of this context's lock-chain - whichever comes first. | |
1983 | */ | |
1984 | static int | |
1985 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1986 | { | |
1987 | int depth = curr->lockdep_depth; | |
1988 | struct held_lock *hlock; | |
ce07a941 BP |
1989 | struct stack_trace trace; |
1990 | int (*save)(struct stack_trace *trace) = save_trace; | |
d6d897ce | 1991 | |
fbb9ce95 | 1992 | /* |
8e18257d PZ |
1993 | * Debugging checks. |
1994 | * | |
1995 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1996 | */ |
8e18257d PZ |
1997 | if (!depth) |
1998 | goto out_bug; | |
fbb9ce95 | 1999 | /* |
8e18257d PZ |
2000 | * At least two relevant locks must exist for this |
2001 | * to be a head: | |
fbb9ce95 | 2002 | */ |
8e18257d PZ |
2003 | if (curr->held_locks[depth].irq_context != |
2004 | curr->held_locks[depth-1].irq_context) | |
2005 | goto out_bug; | |
74c383f1 | 2006 | |
8e18257d PZ |
2007 | for (;;) { |
2008 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 2009 | hlock = curr->held_locks + depth - 1; |
8e18257d | 2010 | /* |
b09be676 BP |
2011 | * Only non-crosslock entries get new dependencies added. |
2012 | * Crosslock entries will be added by commit later: | |
8e18257d | 2013 | */ |
b09be676 | 2014 | if (!cross_lock(hlock->instance)) { |
ce07a941 | 2015 | /* |
b09be676 BP |
2016 | * Only non-recursive-read entries get new dependencies |
2017 | * added: | |
ce07a941 | 2018 | */ |
b09be676 BP |
2019 | if (hlock->read != 2 && hlock->check) { |
2020 | int ret = check_prev_add(curr, hlock, next, | |
2021 | distance, &trace, save); | |
2022 | if (!ret) | |
2023 | return 0; | |
ce07a941 | 2024 | |
b09be676 BP |
2025 | /* |
2026 | * Stop saving stack_trace if save_trace() was | |
2027 | * called at least once: | |
2028 | */ | |
2029 | if (save && ret == 2) | |
2030 | save = NULL; | |
2031 | ||
2032 | /* | |
2033 | * Stop after the first non-trylock entry, | |
2034 | * as non-trylock entries have added their | |
2035 | * own direct dependencies already, so this | |
2036 | * lock is connected to them indirectly: | |
2037 | */ | |
2038 | if (!hlock->trylock) | |
2039 | break; | |
2040 | } | |
74c383f1 | 2041 | } |
8e18257d PZ |
2042 | depth--; |
2043 | /* | |
2044 | * End of lock-stack? | |
2045 | */ | |
2046 | if (!depth) | |
2047 | break; | |
2048 | /* | |
2049 | * Stop the search if we cross into another context: | |
2050 | */ | |
2051 | if (curr->held_locks[depth].irq_context != | |
2052 | curr->held_locks[depth-1].irq_context) | |
2053 | break; | |
fbb9ce95 | 2054 | } |
8e18257d PZ |
2055 | return 1; |
2056 | out_bug: | |
2057 | if (!debug_locks_off_graph_unlock()) | |
2058 | return 0; | |
fbb9ce95 | 2059 | |
0119fee4 PZ |
2060 | /* |
2061 | * Clearly we all shouldn't be here, but since we made it we | |
2062 | * can reliable say we messed up our state. See the above two | |
2063 | * gotos for reasons why we could possibly end up here. | |
2064 | */ | |
8e18257d | 2065 | WARN_ON(1); |
fbb9ce95 | 2066 | |
8e18257d | 2067 | return 0; |
fbb9ce95 IM |
2068 | } |
2069 | ||
8e18257d | 2070 | unsigned long nr_lock_chains; |
443cd507 | 2071 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 2072 | int nr_chain_hlocks; |
443cd507 HY |
2073 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
2074 | ||
2075 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
2076 | { | |
2077 | return lock_classes + chain_hlocks[chain->base + i]; | |
2078 | } | |
8e18257d | 2079 | |
9e4e7554 IM |
2080 | /* |
2081 | * Returns the index of the first held_lock of the current chain | |
2082 | */ | |
2083 | static inline int get_first_held_lock(struct task_struct *curr, | |
2084 | struct held_lock *hlock) | |
2085 | { | |
2086 | int i; | |
2087 | struct held_lock *hlock_curr; | |
2088 | ||
2089 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2090 | hlock_curr = curr->held_locks + i; | |
2091 | if (hlock_curr->irq_context != hlock->irq_context) | |
2092 | break; | |
2093 | ||
2094 | } | |
2095 | ||
2096 | return ++i; | |
2097 | } | |
2098 | ||
5c8a010c | 2099 | #ifdef CONFIG_DEBUG_LOCKDEP |
39e2e173 AAF |
2100 | /* |
2101 | * Returns the next chain_key iteration | |
2102 | */ | |
2103 | static u64 print_chain_key_iteration(int class_idx, u64 chain_key) | |
2104 | { | |
2105 | u64 new_chain_key = iterate_chain_key(chain_key, class_idx); | |
2106 | ||
2107 | printk(" class_idx:%d -> chain_key:%016Lx", | |
2108 | class_idx, | |
2109 | (unsigned long long)new_chain_key); | |
2110 | return new_chain_key; | |
2111 | } | |
2112 | ||
2113 | static void | |
2114 | print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) | |
2115 | { | |
2116 | struct held_lock *hlock; | |
2117 | u64 chain_key = 0; | |
2118 | int depth = curr->lockdep_depth; | |
2119 | int i; | |
2120 | ||
2121 | printk("depth: %u\n", depth + 1); | |
2122 | for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { | |
2123 | hlock = curr->held_locks + i; | |
2124 | chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); | |
2125 | ||
2126 | print_lock(hlock); | |
2127 | } | |
2128 | ||
2129 | print_chain_key_iteration(hlock_next->class_idx, chain_key); | |
2130 | print_lock(hlock_next); | |
2131 | } | |
2132 | ||
2133 | static void print_chain_keys_chain(struct lock_chain *chain) | |
2134 | { | |
2135 | int i; | |
2136 | u64 chain_key = 0; | |
2137 | int class_id; | |
2138 | ||
2139 | printk("depth: %u\n", chain->depth); | |
2140 | for (i = 0; i < chain->depth; i++) { | |
2141 | class_id = chain_hlocks[chain->base + i]; | |
2142 | chain_key = print_chain_key_iteration(class_id + 1, chain_key); | |
2143 | ||
2144 | print_lock_name(lock_classes + class_id); | |
2145 | printk("\n"); | |
2146 | } | |
2147 | } | |
2148 | ||
2149 | static void print_collision(struct task_struct *curr, | |
2150 | struct held_lock *hlock_next, | |
2151 | struct lock_chain *chain) | |
2152 | { | |
681fbec8 | 2153 | pr_warn("\n"); |
a5dd63ef PM |
2154 | pr_warn("============================\n"); |
2155 | pr_warn("WARNING: chain_key collision\n"); | |
39e2e173 | 2156 | print_kernel_ident(); |
a5dd63ef | 2157 | pr_warn("----------------------------\n"); |
681fbec8 PM |
2158 | pr_warn("%s/%d: ", current->comm, task_pid_nr(current)); |
2159 | pr_warn("Hash chain already cached but the contents don't match!\n"); | |
39e2e173 | 2160 | |
681fbec8 | 2161 | pr_warn("Held locks:"); |
39e2e173 AAF |
2162 | print_chain_keys_held_locks(curr, hlock_next); |
2163 | ||
681fbec8 | 2164 | pr_warn("Locks in cached chain:"); |
39e2e173 AAF |
2165 | print_chain_keys_chain(chain); |
2166 | ||
681fbec8 | 2167 | pr_warn("\nstack backtrace:\n"); |
39e2e173 AAF |
2168 | dump_stack(); |
2169 | } | |
5c8a010c | 2170 | #endif |
39e2e173 | 2171 | |
9e4e7554 IM |
2172 | /* |
2173 | * Checks whether the chain and the current held locks are consistent | |
2174 | * in depth and also in content. If they are not it most likely means | |
2175 | * that there was a collision during the calculation of the chain_key. | |
2176 | * Returns: 0 not passed, 1 passed | |
2177 | */ | |
2178 | static int check_no_collision(struct task_struct *curr, | |
2179 | struct held_lock *hlock, | |
2180 | struct lock_chain *chain) | |
2181 | { | |
2182 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2183 | int i, j, id; | |
2184 | ||
2185 | i = get_first_held_lock(curr, hlock); | |
2186 | ||
39e2e173 AAF |
2187 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { |
2188 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2189 | return 0; |
39e2e173 | 2190 | } |
9e4e7554 IM |
2191 | |
2192 | for (j = 0; j < chain->depth - 1; j++, i++) { | |
2193 | id = curr->held_locks[i].class_idx - 1; | |
2194 | ||
39e2e173 AAF |
2195 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { |
2196 | print_collision(curr, hlock, chain); | |
9e4e7554 | 2197 | return 0; |
39e2e173 | 2198 | } |
9e4e7554 IM |
2199 | } |
2200 | #endif | |
2201 | return 1; | |
2202 | } | |
2203 | ||
49347a98 BP |
2204 | /* |
2205 | * This is for building a chain between just two different classes, | |
2206 | * instead of adding a new hlock upon current, which is done by | |
2207 | * add_chain_cache(). | |
2208 | * | |
2209 | * This can be called in any context with two classes, while | |
2210 | * add_chain_cache() must be done within the lock owener's context | |
2211 | * since it uses hlock which might be racy in another context. | |
2212 | */ | |
2213 | static inline int add_chain_cache_classes(unsigned int prev, | |
2214 | unsigned int next, | |
2215 | unsigned int irq_context, | |
2216 | u64 chain_key) | |
2217 | { | |
2218 | struct hlist_head *hash_head = chainhashentry(chain_key); | |
2219 | struct lock_chain *chain; | |
2220 | ||
2221 | /* | |
2222 | * Allocate a new chain entry from the static array, and add | |
2223 | * it to the hash: | |
2224 | */ | |
2225 | ||
2226 | /* | |
2227 | * We might need to take the graph lock, ensure we've got IRQs | |
2228 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2229 | * lockdep won't complain about its own locking errors. | |
2230 | */ | |
2231 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2232 | return 0; | |
2233 | ||
2234 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
2235 | if (!debug_locks_off_graph_unlock()) | |
2236 | return 0; | |
2237 | ||
2238 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); | |
2239 | dump_stack(); | |
2240 | return 0; | |
2241 | } | |
2242 | ||
2243 | chain = lock_chains + nr_lock_chains++; | |
2244 | chain->chain_key = chain_key; | |
2245 | chain->irq_context = irq_context; | |
2246 | chain->depth = 2; | |
2247 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
2248 | chain->base = nr_chain_hlocks; | |
2249 | nr_chain_hlocks += chain->depth; | |
2250 | chain_hlocks[chain->base] = prev - 1; | |
2251 | chain_hlocks[chain->base + 1] = next -1; | |
2252 | } | |
2253 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2254 | /* | |
2255 | * Important for check_no_collision(). | |
2256 | */ | |
2257 | else { | |
2258 | if (!debug_locks_off_graph_unlock()) | |
2259 | return 0; | |
2260 | ||
2261 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); | |
2262 | dump_stack(); | |
2263 | return 0; | |
2264 | } | |
2265 | #endif | |
2266 | ||
2267 | hlist_add_head_rcu(&chain->entry, hash_head); | |
2268 | debug_atomic_inc(chain_lookup_misses); | |
2269 | inc_chains(); | |
2270 | ||
2271 | return 1; | |
2272 | } | |
2273 | ||
fbb9ce95 | 2274 | /* |
545c23f2 BP |
2275 | * Adds a dependency chain into chain hashtable. And must be called with |
2276 | * graph_lock held. | |
2277 | * | |
2278 | * Return 0 if fail, and graph_lock is released. | |
2279 | * Return 1 if succeed, with graph_lock held. | |
fbb9ce95 | 2280 | */ |
545c23f2 BP |
2281 | static inline int add_chain_cache(struct task_struct *curr, |
2282 | struct held_lock *hlock, | |
2283 | u64 chain_key) | |
fbb9ce95 | 2284 | { |
f82b217e | 2285 | struct lock_class *class = hlock_class(hlock); |
a63f38cc | 2286 | struct hlist_head *hash_head = chainhashentry(chain_key); |
fbb9ce95 | 2287 | struct lock_chain *chain; |
e0944ee6 | 2288 | int i, j; |
fbb9ce95 | 2289 | |
545c23f2 BP |
2290 | /* |
2291 | * Allocate a new chain entry from the static array, and add | |
2292 | * it to the hash: | |
2293 | */ | |
2294 | ||
0119fee4 PZ |
2295 | /* |
2296 | * We might need to take the graph lock, ensure we've got IRQs | |
2297 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2298 | * lockdep won't complain about its own locking errors. | |
2299 | */ | |
381a2292 JP |
2300 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2301 | return 0; | |
9e4e7554 | 2302 | |
fbb9ce95 | 2303 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { |
74c383f1 IM |
2304 | if (!debug_locks_off_graph_unlock()) |
2305 | return 0; | |
2306 | ||
2c522836 | 2307 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2308 | dump_stack(); |
fbb9ce95 IM |
2309 | return 0; |
2310 | } | |
2311 | chain = lock_chains + nr_lock_chains++; | |
2312 | chain->chain_key = chain_key; | |
443cd507 | 2313 | chain->irq_context = hlock->irq_context; |
9e4e7554 | 2314 | i = get_first_held_lock(curr, hlock); |
443cd507 | 2315 | chain->depth = curr->lockdep_depth + 1 - i; |
75dd602a PZ |
2316 | |
2317 | BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks)); | |
2318 | BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks)); | |
2319 | BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes)); | |
2320 | ||
e0944ee6 SR |
2321 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2322 | chain->base = nr_chain_hlocks; | |
443cd507 | 2323 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2324 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2325 | chain_hlocks[chain->base + j] = lock_id; |
2326 | } | |
2327 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2328 | } | |
75dd602a PZ |
2329 | |
2330 | if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS) | |
2331 | nr_chain_hlocks += chain->depth; | |
2332 | ||
2333 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2334 | /* | |
2335 | * Important for check_no_collision(). | |
2336 | */ | |
2337 | if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
f9af456a | 2338 | if (!debug_locks_off_graph_unlock()) |
75dd602a PZ |
2339 | return 0; |
2340 | ||
2341 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); | |
2342 | dump_stack(); | |
2343 | return 0; | |
2344 | } | |
2345 | #endif | |
2346 | ||
a63f38cc | 2347 | hlist_add_head_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2348 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2349 | inc_chains(); |
2350 | ||
2351 | return 1; | |
2352 | } | |
2353 | ||
545c23f2 BP |
2354 | /* |
2355 | * Look up a dependency chain. | |
2356 | */ | |
2357 | static inline struct lock_chain *lookup_chain_cache(u64 chain_key) | |
2358 | { | |
2359 | struct hlist_head *hash_head = chainhashentry(chain_key); | |
2360 | struct lock_chain *chain; | |
2361 | ||
2362 | /* | |
2363 | * We can walk it lock-free, because entries only get added | |
2364 | * to the hash: | |
2365 | */ | |
2366 | hlist_for_each_entry_rcu(chain, hash_head, entry) { | |
2367 | if (chain->chain_key == chain_key) { | |
2368 | debug_atomic_inc(chain_lookup_hits); | |
2369 | return chain; | |
2370 | } | |
2371 | } | |
2372 | return NULL; | |
2373 | } | |
2374 | ||
2375 | /* | |
2376 | * If the key is not present yet in dependency chain cache then | |
2377 | * add it and return 1 - in this case the new dependency chain is | |
2378 | * validated. If the key is already hashed, return 0. | |
2379 | * (On return with 1 graph_lock is held.) | |
2380 | */ | |
2381 | static inline int lookup_chain_cache_add(struct task_struct *curr, | |
2382 | struct held_lock *hlock, | |
2383 | u64 chain_key) | |
2384 | { | |
2385 | struct lock_class *class = hlock_class(hlock); | |
2386 | struct lock_chain *chain = lookup_chain_cache(chain_key); | |
2387 | ||
2388 | if (chain) { | |
2389 | cache_hit: | |
2390 | if (!check_no_collision(curr, hlock, chain)) | |
2391 | return 0; | |
2392 | ||
2393 | if (very_verbose(class)) { | |
2394 | printk("\nhash chain already cached, key: " | |
2395 | "%016Lx tail class: [%p] %s\n", | |
2396 | (unsigned long long)chain_key, | |
2397 | class->key, class->name); | |
2398 | } | |
2399 | ||
2400 | return 0; | |
2401 | } | |
2402 | ||
2403 | if (very_verbose(class)) { | |
2404 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", | |
2405 | (unsigned long long)chain_key, class->key, class->name); | |
2406 | } | |
2407 | ||
2408 | if (!graph_lock()) | |
2409 | return 0; | |
2410 | ||
2411 | /* | |
2412 | * We have to walk the chain again locked - to avoid duplicates: | |
2413 | */ | |
2414 | chain = lookup_chain_cache(chain_key); | |
2415 | if (chain) { | |
2416 | graph_unlock(); | |
2417 | goto cache_hit; | |
2418 | } | |
2419 | ||
2420 | if (!add_chain_cache(curr, hlock, chain_key)) | |
2421 | return 0; | |
2422 | ||
2423 | return 1; | |
2424 | } | |
2425 | ||
8e18257d | 2426 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, |
4e6045f1 | 2427 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2428 | { |
2429 | /* | |
2430 | * Trylock needs to maintain the stack of held locks, but it | |
2431 | * does not add new dependencies, because trylock can be done | |
2432 | * in any order. | |
2433 | * | |
2434 | * We look up the chain_key and do the O(N^2) check and update of | |
2435 | * the dependencies only if this is a new dependency chain. | |
545c23f2 | 2436 | * (If lookup_chain_cache_add() return with 1 it acquires |
8e18257d PZ |
2437 | * graph_lock for us) |
2438 | */ | |
fb9edbe9 | 2439 | if (!hlock->trylock && hlock->check && |
545c23f2 | 2440 | lookup_chain_cache_add(curr, hlock, chain_key)) { |
8e18257d PZ |
2441 | /* |
2442 | * Check whether last held lock: | |
2443 | * | |
2444 | * - is irq-safe, if this lock is irq-unsafe | |
2445 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2446 | * | |
2447 | * And check whether the new lock's dependency graph | |
2448 | * could lead back to the previous lock. | |
2449 | * | |
2450 | * any of these scenarios could lead to a deadlock. If | |
2451 | * All validations | |
2452 | */ | |
2453 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2454 | ||
2455 | if (!ret) | |
2456 | return 0; | |
2457 | /* | |
2458 | * Mark recursive read, as we jump over it when | |
2459 | * building dependencies (just like we jump over | |
2460 | * trylock entries): | |
2461 | */ | |
2462 | if (ret == 2) | |
2463 | hlock->read = 2; | |
2464 | /* | |
2465 | * Add dependency only if this lock is not the head | |
2466 | * of the chain, and if it's not a secondary read-lock: | |
2467 | */ | |
545c23f2 | 2468 | if (!chain_head && ret != 2) { |
8e18257d PZ |
2469 | if (!check_prevs_add(curr, hlock)) |
2470 | return 0; | |
545c23f2 BP |
2471 | } |
2472 | ||
8e18257d | 2473 | graph_unlock(); |
545c23f2 BP |
2474 | } else { |
2475 | /* after lookup_chain_cache_add(): */ | |
8e18257d PZ |
2476 | if (unlikely(!debug_locks)) |
2477 | return 0; | |
545c23f2 | 2478 | } |
fbb9ce95 IM |
2479 | |
2480 | return 1; | |
2481 | } | |
8e18257d PZ |
2482 | #else |
2483 | static inline int validate_chain(struct task_struct *curr, | |
2484 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2485 | int chain_head, u64 chain_key) |
8e18257d PZ |
2486 | { |
2487 | return 1; | |
2488 | } | |
ca58abcb | 2489 | #endif |
fbb9ce95 IM |
2490 | |
2491 | /* | |
2492 | * We are building curr_chain_key incrementally, so double-check | |
2493 | * it from scratch, to make sure that it's done correctly: | |
2494 | */ | |
1d09daa5 | 2495 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2496 | { |
2497 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2498 | struct held_lock *hlock, *prev_hlock = NULL; | |
5f18ab5c | 2499 | unsigned int i; |
fbb9ce95 IM |
2500 | u64 chain_key = 0; |
2501 | ||
2502 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2503 | hlock = curr->held_locks + i; | |
2504 | if (chain_key != hlock->prev_chain_key) { | |
2505 | debug_locks_off(); | |
0119fee4 PZ |
2506 | /* |
2507 | * We got mighty confused, our chain keys don't match | |
2508 | * with what we expect, someone trample on our task state? | |
2509 | */ | |
2df8b1d6 | 2510 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2511 | curr->lockdep_depth, i, |
2512 | (unsigned long long)chain_key, | |
2513 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2514 | return; |
2515 | } | |
0119fee4 PZ |
2516 | /* |
2517 | * Whoops ran out of static storage again? | |
2518 | */ | |
5f18ab5c | 2519 | if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) |
381a2292 JP |
2520 | return; |
2521 | ||
fbb9ce95 IM |
2522 | if (prev_hlock && (prev_hlock->irq_context != |
2523 | hlock->irq_context)) | |
2524 | chain_key = 0; | |
5f18ab5c | 2525 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
fbb9ce95 IM |
2526 | prev_hlock = hlock; |
2527 | } | |
2528 | if (chain_key != curr->curr_chain_key) { | |
2529 | debug_locks_off(); | |
0119fee4 PZ |
2530 | /* |
2531 | * More smoking hash instead of calculating it, damn see these | |
2532 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2533 | */ | |
2df8b1d6 | 2534 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2535 | curr->lockdep_depth, i, |
2536 | (unsigned long long)chain_key, | |
2537 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2538 | } |
2539 | #endif | |
2540 | } | |
2541 | ||
282b5c2f SR |
2542 | static void |
2543 | print_usage_bug_scenario(struct held_lock *lock) | |
2544 | { | |
2545 | struct lock_class *class = hlock_class(lock); | |
2546 | ||
2547 | printk(" Possible unsafe locking scenario:\n\n"); | |
2548 | printk(" CPU0\n"); | |
2549 | printk(" ----\n"); | |
2550 | printk(" lock("); | |
2551 | __print_lock_name(class); | |
f943fe0f | 2552 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2553 | printk(" <Interrupt>\n"); |
2554 | printk(" lock("); | |
2555 | __print_lock_name(class); | |
f943fe0f | 2556 | printk(KERN_CONT ");\n"); |
282b5c2f SR |
2557 | printk("\n *** DEADLOCK ***\n\n"); |
2558 | } | |
2559 | ||
8e18257d PZ |
2560 | static int |
2561 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2562 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2563 | { | |
2564 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2565 | return 0; | |
2566 | ||
681fbec8 | 2567 | pr_warn("\n"); |
a5dd63ef PM |
2568 | pr_warn("================================\n"); |
2569 | pr_warn("WARNING: inconsistent lock state\n"); | |
fbdc4b9a | 2570 | print_kernel_ident(); |
a5dd63ef | 2571 | pr_warn("--------------------------------\n"); |
8e18257d | 2572 | |
681fbec8 | 2573 | pr_warn("inconsistent {%s} -> {%s} usage.\n", |
8e18257d PZ |
2574 | usage_str[prev_bit], usage_str[new_bit]); |
2575 | ||
681fbec8 | 2576 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", |
ba25f9dc | 2577 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2578 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2579 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2580 | trace_hardirqs_enabled(curr), | |
2581 | trace_softirqs_enabled(curr)); | |
2582 | print_lock(this); | |
2583 | ||
681fbec8 | 2584 | pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]); |
f82b217e | 2585 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2586 | |
2587 | print_irqtrace_events(curr); | |
681fbec8 | 2588 | pr_warn("\nother info that might help us debug this:\n"); |
282b5c2f SR |
2589 | print_usage_bug_scenario(this); |
2590 | ||
8e18257d PZ |
2591 | lockdep_print_held_locks(curr); |
2592 | ||
681fbec8 | 2593 | pr_warn("\nstack backtrace:\n"); |
8e18257d PZ |
2594 | dump_stack(); |
2595 | ||
2596 | return 0; | |
2597 | } | |
2598 | ||
2599 | /* | |
2600 | * Print out an error if an invalid bit is set: | |
2601 | */ | |
2602 | static inline int | |
2603 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2604 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2605 | { | |
f82b217e | 2606 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2607 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2608 | return 1; | |
2609 | } | |
2610 | ||
2611 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2612 | enum lock_usage_bit new_bit); | |
2613 | ||
81d68a96 | 2614 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2615 | |
2616 | /* | |
2617 | * print irq inversion bug: | |
2618 | */ | |
2619 | static int | |
24208ca7 ML |
2620 | print_irq_inversion_bug(struct task_struct *curr, |
2621 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2622 | struct held_lock *this, int forwards, |
2623 | const char *irqclass) | |
2624 | { | |
dad3d743 SR |
2625 | struct lock_list *entry = other; |
2626 | struct lock_list *middle = NULL; | |
2627 | int depth; | |
2628 | ||
74c383f1 | 2629 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2630 | return 0; |
2631 | ||
681fbec8 | 2632 | pr_warn("\n"); |
a5dd63ef PM |
2633 | pr_warn("========================================================\n"); |
2634 | pr_warn("WARNING: possible irq lock inversion dependency detected\n"); | |
fbdc4b9a | 2635 | print_kernel_ident(); |
a5dd63ef | 2636 | pr_warn("--------------------------------------------------------\n"); |
681fbec8 | 2637 | pr_warn("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2638 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2639 | print_lock(this); |
2640 | if (forwards) | |
681fbec8 | 2641 | pr_warn("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2642 | else |
681fbec8 | 2643 | pr_warn("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2644 | print_lock_name(other->class); |
681fbec8 | 2645 | pr_warn("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
fbb9ce95 | 2646 | |
681fbec8 | 2647 | pr_warn("\nother info that might help us debug this:\n"); |
dad3d743 SR |
2648 | |
2649 | /* Find a middle lock (if one exists) */ | |
2650 | depth = get_lock_depth(other); | |
2651 | do { | |
2652 | if (depth == 0 && (entry != root)) { | |
681fbec8 | 2653 | pr_warn("lockdep:%s bad path found in chain graph\n", __func__); |
dad3d743 SR |
2654 | break; |
2655 | } | |
2656 | middle = entry; | |
2657 | entry = get_lock_parent(entry); | |
2658 | depth--; | |
2659 | } while (entry && entry != root && (depth >= 0)); | |
2660 | if (forwards) | |
2661 | print_irq_lock_scenario(root, other, | |
2662 | middle ? middle->class : root->class, other->class); | |
2663 | else | |
2664 | print_irq_lock_scenario(other, root, | |
2665 | middle ? middle->class : other->class, root->class); | |
2666 | ||
fbb9ce95 IM |
2667 | lockdep_print_held_locks(curr); |
2668 | ||
681fbec8 | 2669 | pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
24208ca7 ML |
2670 | if (!save_trace(&root->trace)) |
2671 | return 0; | |
2672 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 | 2673 | |
681fbec8 | 2674 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
2675 | dump_stack(); |
2676 | ||
2677 | return 0; | |
2678 | } | |
2679 | ||
2680 | /* | |
2681 | * Prove that in the forwards-direction subgraph starting at <this> | |
2682 | * there is no lock matching <mask>: | |
2683 | */ | |
2684 | static int | |
2685 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2686 | enum lock_usage_bit bit, const char *irqclass) | |
2687 | { | |
2688 | int ret; | |
d7aaba14 ML |
2689 | struct lock_list root; |
2690 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2691 | |
d7aaba14 ML |
2692 | root.parent = NULL; |
2693 | root.class = hlock_class(this); | |
2694 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2695 | if (ret < 0) |
2696 | return print_bfs_bug(ret); | |
2697 | if (ret == 1) | |
2698 | return ret; | |
fbb9ce95 | 2699 | |
24208ca7 | 2700 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2701 | this, 1, irqclass); |
fbb9ce95 IM |
2702 | } |
2703 | ||
2704 | /* | |
2705 | * Prove that in the backwards-direction subgraph starting at <this> | |
2706 | * there is no lock matching <mask>: | |
2707 | */ | |
2708 | static int | |
2709 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2710 | enum lock_usage_bit bit, const char *irqclass) | |
2711 | { | |
2712 | int ret; | |
d7aaba14 ML |
2713 | struct lock_list root; |
2714 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2715 | |
d7aaba14 ML |
2716 | root.parent = NULL; |
2717 | root.class = hlock_class(this); | |
2718 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2719 | if (ret < 0) |
2720 | return print_bfs_bug(ret); | |
2721 | if (ret == 1) | |
2722 | return ret; | |
fbb9ce95 | 2723 | |
24208ca7 | 2724 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2725 | this, 0, irqclass); |
fbb9ce95 IM |
2726 | } |
2727 | ||
3117df04 | 2728 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2729 | { |
2730 | printk("irq event stamp: %u\n", curr->irq_events); | |
f943fe0f DV |
2731 | printk("hardirqs last enabled at (%u): [<%p>] %pS\n", |
2732 | curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip, | |
2733 | (void *)curr->hardirq_enable_ip); | |
2734 | printk("hardirqs last disabled at (%u): [<%p>] %pS\n", | |
2735 | curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip, | |
2736 | (void *)curr->hardirq_disable_ip); | |
2737 | printk("softirqs last enabled at (%u): [<%p>] %pS\n", | |
2738 | curr->softirq_enable_event, (void *)curr->softirq_enable_ip, | |
2739 | (void *)curr->softirq_enable_ip); | |
2740 | printk("softirqs last disabled at (%u): [<%p>] %pS\n", | |
2741 | curr->softirq_disable_event, (void *)curr->softirq_disable_ip, | |
2742 | (void *)curr->softirq_disable_ip); | |
fbb9ce95 IM |
2743 | } |
2744 | ||
cd95302d | 2745 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2746 | { |
8e18257d PZ |
2747 | #if HARDIRQ_VERBOSE |
2748 | return class_filter(class); | |
2749 | #endif | |
fbb9ce95 IM |
2750 | return 0; |
2751 | } | |
2752 | ||
cd95302d | 2753 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2754 | { |
8e18257d PZ |
2755 | #if SOFTIRQ_VERBOSE |
2756 | return class_filter(class); | |
2757 | #endif | |
2758 | return 0; | |
fbb9ce95 IM |
2759 | } |
2760 | ||
2761 | #define STRICT_READ_CHECKS 1 | |
2762 | ||
cd95302d PZ |
2763 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2764 | #define LOCKDEP_STATE(__STATE) \ | |
2765 | __STATE##_verbose, | |
2766 | #include "lockdep_states.h" | |
2767 | #undef LOCKDEP_STATE | |
2768 | }; | |
2769 | ||
2770 | static inline int state_verbose(enum lock_usage_bit bit, | |
2771 | struct lock_class *class) | |
2772 | { | |
2773 | return state_verbose_f[bit >> 2](class); | |
2774 | } | |
2775 | ||
42c50d54 PZ |
2776 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2777 | enum lock_usage_bit bit, const char *name); | |
2778 | ||
6a6904d3 | 2779 | static int |
1c21f14e PZ |
2780 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2781 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2782 | { |
f989209e | 2783 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2784 | int read = new_bit & 1; |
42c50d54 PZ |
2785 | int dir = new_bit & 2; |
2786 | ||
38aa2714 PZ |
2787 | /* |
2788 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2789 | * has ENABLED state, which would allow recursion deadlocks. | |
2790 | * | |
2791 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2792 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2793 | */ | |
42c50d54 PZ |
2794 | check_usage_f usage = dir ? |
2795 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2796 | |
38aa2714 PZ |
2797 | /* |
2798 | * Validate that this particular lock does not have conflicting | |
2799 | * usage states. | |
2800 | */ | |
6a6904d3 PZ |
2801 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2802 | return 0; | |
42c50d54 | 2803 | |
38aa2714 PZ |
2804 | /* |
2805 | * Validate that the lock dependencies don't have conflicting usage | |
2806 | * states. | |
2807 | */ | |
2808 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2809 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2810 | return 0; |
780e820b | 2811 | |
38aa2714 PZ |
2812 | /* |
2813 | * Check for read in write conflicts | |
2814 | */ | |
2815 | if (!read) { | |
2816 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2817 | return 0; | |
2818 | ||
2819 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2820 | !usage(curr, this, excl_bit + 1, |
2821 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2822 | return 0; |
2823 | } | |
780e820b | 2824 | |
cd95302d | 2825 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2826 | return 2; |
2827 | ||
2828 | return 1; | |
2829 | } | |
2830 | ||
cf40bd16 | 2831 | enum mark_type { |
36bfb9bb PZ |
2832 | #define LOCKDEP_STATE(__STATE) __STATE, |
2833 | #include "lockdep_states.h" | |
2834 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2835 | }; |
2836 | ||
fbb9ce95 IM |
2837 | /* |
2838 | * Mark all held locks with a usage bit: | |
2839 | */ | |
1d09daa5 | 2840 | static int |
cf40bd16 | 2841 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2842 | { |
2843 | enum lock_usage_bit usage_bit; | |
2844 | struct held_lock *hlock; | |
2845 | int i; | |
2846 | ||
2847 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2848 | hlock = curr->held_locks + i; | |
2849 | ||
cf2ad4d1 PZ |
2850 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2851 | if (hlock->read) | |
2852 | usage_bit += 1; /* READ */ | |
2853 | ||
2854 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2855 | |
34d0ed5e | 2856 | if (!hlock->check) |
efbe2eee PZ |
2857 | continue; |
2858 | ||
4ff773bb | 2859 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2860 | return 0; |
2861 | } | |
2862 | ||
2863 | return 1; | |
2864 | } | |
2865 | ||
fbb9ce95 IM |
2866 | /* |
2867 | * Hardirqs will be enabled: | |
2868 | */ | |
dd4e5d3a | 2869 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2870 | { |
2871 | struct task_struct *curr = current; | |
fbb9ce95 | 2872 | |
fbb9ce95 IM |
2873 | /* we'll do an OFF -> ON transition: */ |
2874 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2875 | |
fbb9ce95 IM |
2876 | /* |
2877 | * We are going to turn hardirqs on, so set the | |
2878 | * usage bit for all held locks: | |
2879 | */ | |
cf40bd16 | 2880 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2881 | return; |
2882 | /* | |
2883 | * If we have softirqs enabled, then set the usage | |
2884 | * bit for all held locks. (disabled hardirqs prevented | |
2885 | * this bit from being set before) | |
2886 | */ | |
2887 | if (curr->softirqs_enabled) | |
cf40bd16 | 2888 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2889 | return; |
2890 | ||
8e18257d PZ |
2891 | curr->hardirq_enable_ip = ip; |
2892 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2893 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2894 | } |
dd4e5d3a | 2895 | |
b35f8305 | 2896 | __visible void trace_hardirqs_on_caller(unsigned long ip) |
dd4e5d3a PZ |
2897 | { |
2898 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2899 | ||
2900 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2901 | return; | |
2902 | ||
7d36b26b PZ |
2903 | if (unlikely(current->hardirqs_enabled)) { |
2904 | /* | |
2905 | * Neither irq nor preemption are disabled here | |
2906 | * so this is racy by nature but losing one hit | |
2907 | * in a stat is not a big deal. | |
2908 | */ | |
2909 | __debug_atomic_inc(redundant_hardirqs_on); | |
2910 | return; | |
2911 | } | |
2912 | ||
0119fee4 PZ |
2913 | /* |
2914 | * We're enabling irqs and according to our state above irqs weren't | |
2915 | * already enabled, yet we find the hardware thinks they are in fact | |
2916 | * enabled.. someone messed up their IRQ state tracing. | |
2917 | */ | |
dd4e5d3a PZ |
2918 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2919 | return; | |
2920 | ||
0119fee4 PZ |
2921 | /* |
2922 | * See the fine text that goes along with this variable definition. | |
2923 | */ | |
7d36b26b PZ |
2924 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2925 | return; | |
2926 | ||
0119fee4 PZ |
2927 | /* |
2928 | * Can't allow enabling interrupts while in an interrupt handler, | |
2929 | * that's general bad form and such. Recursion, limited stack etc.. | |
2930 | */ | |
7d36b26b PZ |
2931 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2932 | return; | |
2933 | ||
dd4e5d3a PZ |
2934 | current->lockdep_recursion = 1; |
2935 | __trace_hardirqs_on_caller(ip); | |
2936 | current->lockdep_recursion = 0; | |
2937 | } | |
81d68a96 | 2938 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2939 | |
1d09daa5 | 2940 | void trace_hardirqs_on(void) |
81d68a96 SR |
2941 | { |
2942 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2943 | } | |
8e18257d PZ |
2944 | EXPORT_SYMBOL(trace_hardirqs_on); |
2945 | ||
2946 | /* | |
2947 | * Hardirqs were disabled: | |
2948 | */ | |
b35f8305 | 2949 | __visible void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2950 | { |
2951 | struct task_struct *curr = current; | |
2952 | ||
6afe40b4 | 2953 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2954 | |
8e18257d PZ |
2955 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2956 | return; | |
2957 | ||
0119fee4 PZ |
2958 | /* |
2959 | * So we're supposed to get called after you mask local IRQs, but for | |
2960 | * some reason the hardware doesn't quite think you did a proper job. | |
2961 | */ | |
8e18257d PZ |
2962 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2963 | return; | |
2964 | ||
2965 | if (curr->hardirqs_enabled) { | |
2966 | /* | |
2967 | * We have done an ON -> OFF transition: | |
2968 | */ | |
2969 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2970 | curr->hardirq_disable_ip = ip; |
8e18257d | 2971 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2972 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2973 | } else |
bd6d29c2 | 2974 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2975 | } |
81d68a96 | 2976 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2977 | |
1d09daa5 | 2978 | void trace_hardirqs_off(void) |
81d68a96 SR |
2979 | { |
2980 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2981 | } | |
8e18257d PZ |
2982 | EXPORT_SYMBOL(trace_hardirqs_off); |
2983 | ||
2984 | /* | |
2985 | * Softirqs will be enabled: | |
2986 | */ | |
2987 | void trace_softirqs_on(unsigned long ip) | |
2988 | { | |
2989 | struct task_struct *curr = current; | |
2990 | ||
dd4e5d3a | 2991 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2992 | return; |
2993 | ||
0119fee4 PZ |
2994 | /* |
2995 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2996 | * funny state and nesting things. | |
2997 | */ | |
8e18257d PZ |
2998 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2999 | return; | |
3000 | ||
3001 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 3002 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
3003 | return; |
3004 | } | |
3005 | ||
dd4e5d3a | 3006 | current->lockdep_recursion = 1; |
8e18257d PZ |
3007 | /* |
3008 | * We'll do an OFF -> ON transition: | |
3009 | */ | |
3010 | curr->softirqs_enabled = 1; | |
3011 | curr->softirq_enable_ip = ip; | |
3012 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 3013 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
3014 | /* |
3015 | * We are going to turn softirqs on, so set the | |
3016 | * usage bit for all held locks, if hardirqs are | |
3017 | * enabled too: | |
3018 | */ | |
3019 | if (curr->hardirqs_enabled) | |
cf40bd16 | 3020 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 3021 | current->lockdep_recursion = 0; |
8e18257d PZ |
3022 | } |
3023 | ||
3024 | /* | |
3025 | * Softirqs were disabled: | |
3026 | */ | |
3027 | void trace_softirqs_off(unsigned long ip) | |
3028 | { | |
3029 | struct task_struct *curr = current; | |
3030 | ||
dd4e5d3a | 3031 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
3032 | return; |
3033 | ||
0119fee4 PZ |
3034 | /* |
3035 | * We fancy IRQs being disabled here, see softirq.c | |
3036 | */ | |
8e18257d PZ |
3037 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3038 | return; | |
3039 | ||
3040 | if (curr->softirqs_enabled) { | |
3041 | /* | |
3042 | * We have done an ON -> OFF transition: | |
3043 | */ | |
3044 | curr->softirqs_enabled = 0; | |
3045 | curr->softirq_disable_ip = ip; | |
3046 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 3047 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
3048 | /* |
3049 | * Whoops, we wanted softirqs off, so why aren't they? | |
3050 | */ | |
8e18257d PZ |
3051 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
3052 | } else | |
bd6d29c2 | 3053 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
3054 | } |
3055 | ||
3056 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) | |
3057 | { | |
3058 | /* | |
3059 | * If non-trylock use in a hardirq or softirq context, then | |
3060 | * mark the lock as used in these contexts: | |
3061 | */ | |
3062 | if (!hlock->trylock) { | |
3063 | if (hlock->read) { | |
3064 | if (curr->hardirq_context) | |
3065 | if (!mark_lock(curr, hlock, | |
3066 | LOCK_USED_IN_HARDIRQ_READ)) | |
3067 | return 0; | |
3068 | if (curr->softirq_context) | |
3069 | if (!mark_lock(curr, hlock, | |
3070 | LOCK_USED_IN_SOFTIRQ_READ)) | |
3071 | return 0; | |
3072 | } else { | |
3073 | if (curr->hardirq_context) | |
3074 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
3075 | return 0; | |
3076 | if (curr->softirq_context) | |
3077 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
3078 | return 0; | |
3079 | } | |
3080 | } | |
3081 | if (!hlock->hardirqs_off) { | |
3082 | if (hlock->read) { | |
3083 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3084 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
3085 | return 0; |
3086 | if (curr->softirqs_enabled) | |
3087 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3088 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
3089 | return 0; |
3090 | } else { | |
3091 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3092 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
3093 | return 0; |
3094 | if (curr->softirqs_enabled) | |
3095 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 3096 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
3097 | return 0; |
3098 | } | |
3099 | } | |
3100 | ||
3101 | return 1; | |
3102 | } | |
3103 | ||
c2469756 BF |
3104 | static inline unsigned int task_irq_context(struct task_struct *task) |
3105 | { | |
3106 | return 2 * !!task->hardirq_context + !!task->softirq_context; | |
3107 | } | |
3108 | ||
8e18257d PZ |
3109 | static int separate_irq_context(struct task_struct *curr, |
3110 | struct held_lock *hlock) | |
3111 | { | |
3112 | unsigned int depth = curr->lockdep_depth; | |
3113 | ||
3114 | /* | |
3115 | * Keep track of points where we cross into an interrupt context: | |
3116 | */ | |
8e18257d PZ |
3117 | if (depth) { |
3118 | struct held_lock *prev_hlock; | |
3119 | ||
3120 | prev_hlock = curr->held_locks + depth-1; | |
3121 | /* | |
3122 | * If we cross into another context, reset the | |
3123 | * hash key (this also prevents the checking and the | |
3124 | * adding of the dependency to 'prev'): | |
3125 | */ | |
3126 | if (prev_hlock->irq_context != hlock->irq_context) | |
3127 | return 1; | |
3128 | } | |
3129 | return 0; | |
fbb9ce95 IM |
3130 | } |
3131 | ||
0119fee4 | 3132 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 3133 | |
8e18257d PZ |
3134 | static inline |
3135 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
3136 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 3137 | { |
0119fee4 | 3138 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
3139 | return 1; |
3140 | } | |
fbb9ce95 | 3141 | |
8e18257d PZ |
3142 | static inline int mark_irqflags(struct task_struct *curr, |
3143 | struct held_lock *hlock) | |
3144 | { | |
3145 | return 1; | |
3146 | } | |
fbb9ce95 | 3147 | |
c2469756 BF |
3148 | static inline unsigned int task_irq_context(struct task_struct *task) |
3149 | { | |
3150 | return 0; | |
3151 | } | |
3152 | ||
8e18257d PZ |
3153 | static inline int separate_irq_context(struct task_struct *curr, |
3154 | struct held_lock *hlock) | |
3155 | { | |
3156 | return 0; | |
fbb9ce95 IM |
3157 | } |
3158 | ||
0119fee4 | 3159 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
3160 | |
3161 | /* | |
8e18257d | 3162 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 3163 | */ |
1d09daa5 | 3164 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 3165 | enum lock_usage_bit new_bit) |
fbb9ce95 | 3166 | { |
8e18257d | 3167 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
3168 | |
3169 | /* | |
8e18257d PZ |
3170 | * If already set then do not dirty the cacheline, |
3171 | * nor do any checks: | |
fbb9ce95 | 3172 | */ |
f82b217e | 3173 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
3174 | return 1; |
3175 | ||
3176 | if (!graph_lock()) | |
3177 | return 0; | |
fbb9ce95 | 3178 | /* |
25985edc | 3179 | * Make sure we didn't race: |
fbb9ce95 | 3180 | */ |
f82b217e | 3181 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
3182 | graph_unlock(); |
3183 | return 1; | |
3184 | } | |
fbb9ce95 | 3185 | |
f82b217e | 3186 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 3187 | |
f82b217e | 3188 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 3189 | return 0; |
fbb9ce95 | 3190 | |
8e18257d | 3191 | switch (new_bit) { |
5346417e PZ |
3192 | #define LOCKDEP_STATE(__STATE) \ |
3193 | case LOCK_USED_IN_##__STATE: \ | |
3194 | case LOCK_USED_IN_##__STATE##_READ: \ | |
3195 | case LOCK_ENABLED_##__STATE: \ | |
3196 | case LOCK_ENABLED_##__STATE##_READ: | |
3197 | #include "lockdep_states.h" | |
3198 | #undef LOCKDEP_STATE | |
8e18257d PZ |
3199 | ret = mark_lock_irq(curr, this, new_bit); |
3200 | if (!ret) | |
3201 | return 0; | |
3202 | break; | |
3203 | case LOCK_USED: | |
bd6d29c2 | 3204 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
3205 | break; |
3206 | default: | |
3207 | if (!debug_locks_off_graph_unlock()) | |
3208 | return 0; | |
3209 | WARN_ON(1); | |
3210 | return 0; | |
3211 | } | |
fbb9ce95 | 3212 | |
8e18257d PZ |
3213 | graph_unlock(); |
3214 | ||
3215 | /* | |
3216 | * We must printk outside of the graph_lock: | |
3217 | */ | |
3218 | if (ret == 2) { | |
3219 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
3220 | print_lock(this); | |
3221 | print_irqtrace_events(curr); | |
3222 | dump_stack(); | |
3223 | } | |
3224 | ||
3225 | return ret; | |
3226 | } | |
fbb9ce95 IM |
3227 | |
3228 | /* | |
3229 | * Initialize a lock instance's lock-class mapping info: | |
3230 | */ | |
b09be676 | 3231 | static void __lockdep_init_map(struct lockdep_map *lock, const char *name, |
4dfbb9d8 | 3232 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 3233 | { |
d3d03d4f YZ |
3234 | int i; |
3235 | ||
3236 | kmemcheck_mark_initialized(lock, sizeof(*lock)); | |
3237 | ||
3238 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) | |
3239 | lock->class_cache[i] = NULL; | |
62016250 | 3240 | |
c8a25005 PZ |
3241 | #ifdef CONFIG_LOCK_STAT |
3242 | lock->cpu = raw_smp_processor_id(); | |
3243 | #endif | |
3244 | ||
0119fee4 PZ |
3245 | /* |
3246 | * Can't be having no nameless bastards around this place! | |
3247 | */ | |
c8a25005 PZ |
3248 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
3249 | lock->name = "NULL"; | |
fbb9ce95 | 3250 | return; |
c8a25005 PZ |
3251 | } |
3252 | ||
3253 | lock->name = name; | |
fbb9ce95 | 3254 | |
0119fee4 PZ |
3255 | /* |
3256 | * No key, no joy, we need to hash something. | |
3257 | */ | |
fbb9ce95 IM |
3258 | if (DEBUG_LOCKS_WARN_ON(!key)) |
3259 | return; | |
fbb9ce95 IM |
3260 | /* |
3261 | * Sanity check, the lock-class key must be persistent: | |
3262 | */ | |
3263 | if (!static_obj(key)) { | |
3264 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
3265 | /* |
3266 | * What it says above ^^^^^, I suggest you read it. | |
3267 | */ | |
fbb9ce95 IM |
3268 | DEBUG_LOCKS_WARN_ON(1); |
3269 | return; | |
3270 | } | |
fbb9ce95 | 3271 | lock->key = key; |
c8a25005 PZ |
3272 | |
3273 | if (unlikely(!debug_locks)) | |
3274 | return; | |
3275 | ||
35a9393c PZ |
3276 | if (subclass) { |
3277 | unsigned long flags; | |
3278 | ||
3279 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3280 | return; | |
3281 | ||
3282 | raw_local_irq_save(flags); | |
3283 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3284 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3285 | current->lockdep_recursion = 0; |
3286 | raw_local_irq_restore(flags); | |
3287 | } | |
fbb9ce95 | 3288 | } |
b09be676 BP |
3289 | |
3290 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
3291 | struct lock_class_key *key, int subclass) | |
3292 | { | |
3293 | cross_init(lock, 0); | |
3294 | __lockdep_init_map(lock, name, key, subclass); | |
3295 | } | |
fbb9ce95 IM |
3296 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3297 | ||
b09be676 BP |
3298 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE |
3299 | void lockdep_init_map_crosslock(struct lockdep_map *lock, const char *name, | |
3300 | struct lock_class_key *key, int subclass) | |
3301 | { | |
3302 | cross_init(lock, 1); | |
3303 | __lockdep_init_map(lock, name, key, subclass); | |
3304 | } | |
3305 | EXPORT_SYMBOL_GPL(lockdep_init_map_crosslock); | |
3306 | #endif | |
3307 | ||
1704f47b | 3308 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3309 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3310 | |
d0945950 ML |
3311 | static int |
3312 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3313 | struct held_lock *hlock, | |
3314 | unsigned long ip) | |
3315 | { | |
3316 | if (!debug_locks_off()) | |
3317 | return 0; | |
3318 | if (debug_locks_silent) | |
3319 | return 0; | |
3320 | ||
681fbec8 | 3321 | pr_warn("\n"); |
a5dd63ef PM |
3322 | pr_warn("==================================\n"); |
3323 | pr_warn("WARNING: Nested lock was not taken\n"); | |
d0945950 | 3324 | print_kernel_ident(); |
a5dd63ef | 3325 | pr_warn("----------------------------------\n"); |
d0945950 | 3326 | |
681fbec8 | 3327 | pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); |
d0945950 ML |
3328 | print_lock(hlock); |
3329 | ||
681fbec8 PM |
3330 | pr_warn("\nbut this task is not holding:\n"); |
3331 | pr_warn("%s\n", hlock->nest_lock->name); | |
d0945950 | 3332 | |
681fbec8 | 3333 | pr_warn("\nstack backtrace:\n"); |
d0945950 ML |
3334 | dump_stack(); |
3335 | ||
681fbec8 | 3336 | pr_warn("\nother info that might help us debug this:\n"); |
d0945950 ML |
3337 | lockdep_print_held_locks(curr); |
3338 | ||
681fbec8 | 3339 | pr_warn("\nstack backtrace:\n"); |
d0945950 ML |
3340 | dump_stack(); |
3341 | ||
3342 | return 0; | |
3343 | } | |
3344 | ||
f8319483 | 3345 | static int __lock_is_held(struct lockdep_map *lock, int read); |
d0945950 | 3346 | |
fbb9ce95 IM |
3347 | /* |
3348 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3349 | * We maintain the dependency maps and validate the locking attempt: | |
3350 | */ | |
3351 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3352 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3353 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3354 | int references, int pin_count) |
fbb9ce95 IM |
3355 | { |
3356 | struct task_struct *curr = current; | |
d6d897ce | 3357 | struct lock_class *class = NULL; |
fbb9ce95 | 3358 | struct held_lock *hlock; |
5f18ab5c | 3359 | unsigned int depth; |
fbb9ce95 | 3360 | int chain_head = 0; |
bb97a91e | 3361 | int class_idx; |
fbb9ce95 | 3362 | u64 chain_key; |
b09be676 | 3363 | int ret; |
fbb9ce95 IM |
3364 | |
3365 | if (unlikely(!debug_locks)) | |
3366 | return 0; | |
3367 | ||
0119fee4 PZ |
3368 | /* |
3369 | * Lockdep should run with IRQs disabled, otherwise we could | |
3370 | * get an interrupt which would want to take locks, which would | |
3371 | * end up in lockdep and have you got a head-ache already? | |
3372 | */ | |
fbb9ce95 IM |
3373 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3374 | return 0; | |
3375 | ||
fb9edbe9 ON |
3376 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3377 | check = 0; | |
1704f47b | 3378 | |
62016250 HM |
3379 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3380 | class = lock->class_cache[subclass]; | |
d6d897ce | 3381 | /* |
62016250 | 3382 | * Not cached? |
d6d897ce | 3383 | */ |
fbb9ce95 | 3384 | if (unlikely(!class)) { |
4dfbb9d8 | 3385 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3386 | if (!class) |
3387 | return 0; | |
3388 | } | |
bd6d29c2 | 3389 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3390 | if (very_verbose(class)) { |
3391 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3392 | if (class->name_version > 1) | |
f943fe0f DV |
3393 | printk(KERN_CONT "#%d", class->name_version); |
3394 | printk(KERN_CONT "\n"); | |
fbb9ce95 IM |
3395 | dump_stack(); |
3396 | } | |
3397 | ||
3398 | /* | |
3399 | * Add the lock to the list of currently held locks. | |
3400 | * (we dont increase the depth just yet, up until the | |
3401 | * dependency checks are done) | |
3402 | */ | |
3403 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3404 | /* |
3405 | * Ran out of static storage for our per-task lock stack again have we? | |
3406 | */ | |
fbb9ce95 IM |
3407 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3408 | return 0; | |
3409 | ||
bb97a91e PZ |
3410 | class_idx = class - lock_classes + 1; |
3411 | ||
b09be676 BP |
3412 | /* TODO: nest_lock is not implemented for crosslock yet. */ |
3413 | if (depth && !cross_lock(lock)) { | |
bb97a91e PZ |
3414 | hlock = curr->held_locks + depth - 1; |
3415 | if (hlock->class_idx == class_idx && nest_lock) { | |
7fb4a2ce PZ |
3416 | if (hlock->references) { |
3417 | /* | |
3418 | * Check: unsigned int references:12, overflow. | |
3419 | */ | |
3420 | if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) | |
3421 | return 0; | |
3422 | ||
bb97a91e | 3423 | hlock->references++; |
7fb4a2ce | 3424 | } else { |
bb97a91e | 3425 | hlock->references = 2; |
7fb4a2ce | 3426 | } |
bb97a91e PZ |
3427 | |
3428 | return 1; | |
3429 | } | |
3430 | } | |
3431 | ||
fbb9ce95 | 3432 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3433 | /* |
3434 | * Plain impossible, we just registered it and checked it weren't no | |
3435 | * NULL like.. I bet this mushroom I ate was good! | |
3436 | */ | |
f82b217e DJ |
3437 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3438 | return 0; | |
bb97a91e | 3439 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3440 | hlock->acquire_ip = ip; |
3441 | hlock->instance = lock; | |
7531e2f3 | 3442 | hlock->nest_lock = nest_lock; |
c2469756 | 3443 | hlock->irq_context = task_irq_context(curr); |
fbb9ce95 IM |
3444 | hlock->trylock = trylock; |
3445 | hlock->read = read; | |
3446 | hlock->check = check; | |
6951b12a | 3447 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3448 | hlock->references = references; |
f20786ff PZ |
3449 | #ifdef CONFIG_LOCK_STAT |
3450 | hlock->waittime_stamp = 0; | |
3365e779 | 3451 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3452 | #endif |
21199f27 | 3453 | hlock->pin_count = pin_count; |
fbb9ce95 | 3454 | |
fb9edbe9 | 3455 | if (check && !mark_irqflags(curr, hlock)) |
8e18257d PZ |
3456 | return 0; |
3457 | ||
fbb9ce95 | 3458 | /* mark it as used: */ |
4ff773bb | 3459 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3460 | return 0; |
8e18257d | 3461 | |
fbb9ce95 | 3462 | /* |
17aacfb9 | 3463 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3464 | * lock keys along the dependency chain. We save the hash value |
3465 | * at every step so that we can get the current hash easily | |
3466 | * after unlock. The chain hash is then used to cache dependency | |
3467 | * results. | |
3468 | * | |
3469 | * The 'key ID' is what is the most compact key value to drive | |
3470 | * the hash, not class->key. | |
3471 | */ | |
0119fee4 PZ |
3472 | /* |
3473 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3474 | */ | |
5f18ab5c | 3475 | if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) |
fbb9ce95 IM |
3476 | return 0; |
3477 | ||
3478 | chain_key = curr->curr_chain_key; | |
3479 | if (!depth) { | |
0119fee4 PZ |
3480 | /* |
3481 | * How can we have a chain hash when we ain't got no keys?! | |
3482 | */ | |
fbb9ce95 IM |
3483 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3484 | return 0; | |
3485 | chain_head = 1; | |
3486 | } | |
3487 | ||
3488 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3489 | if (separate_irq_context(curr, hlock)) { |
3490 | chain_key = 0; | |
3491 | chain_head = 1; | |
fbb9ce95 | 3492 | } |
5f18ab5c | 3493 | chain_key = iterate_chain_key(chain_key, class_idx); |
fbb9ce95 | 3494 | |
f8319483 | 3495 | if (nest_lock && !__lock_is_held(nest_lock, -1)) |
d0945950 ML |
3496 | return print_lock_nested_lock_not_held(curr, hlock, ip); |
3497 | ||
3aa416b0 | 3498 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3499 | return 0; |
381a2292 | 3500 | |
b09be676 BP |
3501 | ret = lock_acquire_crosslock(hlock); |
3502 | /* | |
3503 | * 2 means normal acquire operations are needed. Otherwise, it's | |
3504 | * ok just to return with '0:fail, 1:success'. | |
3505 | */ | |
3506 | if (ret != 2) | |
3507 | return ret; | |
3508 | ||
3aa416b0 | 3509 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3510 | curr->lockdep_depth++; |
3511 | check_chain_key(curr); | |
60e114d1 JP |
3512 | #ifdef CONFIG_DEBUG_LOCKDEP |
3513 | if (unlikely(!debug_locks)) | |
3514 | return 0; | |
3515 | #endif | |
fbb9ce95 IM |
3516 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3517 | debug_locks_off(); | |
2c522836 DJ |
3518 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3519 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3520 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3521 | |
3522 | lockdep_print_held_locks(current); | |
3523 | debug_show_all_locks(); | |
eedeeabd | 3524 | dump_stack(); |
c0540606 | 3525 | |
fbb9ce95 IM |
3526 | return 0; |
3527 | } | |
381a2292 | 3528 | |
fbb9ce95 IM |
3529 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3530 | max_lockdep_depth = curr->lockdep_depth; | |
3531 | ||
3532 | return 1; | |
3533 | } | |
3534 | ||
3535 | static int | |
f86f7554 | 3536 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3537 | unsigned long ip) |
3538 | { | |
3539 | if (!debug_locks_off()) | |
3540 | return 0; | |
3541 | if (debug_locks_silent) | |
3542 | return 0; | |
3543 | ||
681fbec8 | 3544 | pr_warn("\n"); |
a5dd63ef PM |
3545 | pr_warn("=====================================\n"); |
3546 | pr_warn("WARNING: bad unlock balance detected!\n"); | |
fbdc4b9a | 3547 | print_kernel_ident(); |
a5dd63ef | 3548 | pr_warn("-------------------------------------\n"); |
681fbec8 | 3549 | pr_warn("%s/%d is trying to release lock (", |
ba25f9dc | 3550 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 | 3551 | print_lockdep_cache(lock); |
681fbec8 | 3552 | pr_cont(") at:\n"); |
fbb9ce95 | 3553 | print_ip_sym(ip); |
681fbec8 PM |
3554 | pr_warn("but there are no more locks to release!\n"); |
3555 | pr_warn("\nother info that might help us debug this:\n"); | |
fbb9ce95 IM |
3556 | lockdep_print_held_locks(curr); |
3557 | ||
681fbec8 | 3558 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
3559 | dump_stack(); |
3560 | ||
3561 | return 0; | |
3562 | } | |
3563 | ||
bb97a91e PZ |
3564 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3565 | { | |
3566 | if (hlock->instance == lock) | |
3567 | return 1; | |
3568 | ||
3569 | if (hlock->references) { | |
62016250 | 3570 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3571 | |
3572 | if (!class) | |
3573 | class = look_up_lock_class(lock, 0); | |
3574 | ||
80e0401e PZ |
3575 | /* |
3576 | * If look_up_lock_class() failed to find a class, we're trying | |
3577 | * to test if we hold a lock that has never yet been acquired. | |
3578 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3579 | * holding it either, so report failure. | |
3580 | */ | |
383776fa | 3581 | if (IS_ERR_OR_NULL(class)) |
bb97a91e PZ |
3582 | return 0; |
3583 | ||
0119fee4 PZ |
3584 | /* |
3585 | * References, but not a lock we're actually ref-counting? | |
3586 | * State got messed up, follow the sites that change ->references | |
3587 | * and try to make sense of it. | |
3588 | */ | |
bb97a91e PZ |
3589 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3590 | return 0; | |
3591 | ||
3592 | if (hlock->class_idx == class - lock_classes + 1) | |
3593 | return 1; | |
3594 | } | |
3595 | ||
3596 | return 0; | |
3597 | } | |
3598 | ||
41c2c5b8 O |
3599 | /* @depth must not be zero */ |
3600 | static struct held_lock *find_held_lock(struct task_struct *curr, | |
3601 | struct lockdep_map *lock, | |
3602 | unsigned int depth, int *idx) | |
3603 | { | |
3604 | struct held_lock *ret, *hlock, *prev_hlock; | |
3605 | int i; | |
3606 | ||
3607 | i = depth - 1; | |
3608 | hlock = curr->held_locks + i; | |
3609 | ret = hlock; | |
3610 | if (match_held_lock(hlock, lock)) | |
3611 | goto out; | |
3612 | ||
3613 | ret = NULL; | |
3614 | for (i--, prev_hlock = hlock--; | |
3615 | i >= 0; | |
3616 | i--, prev_hlock = hlock--) { | |
3617 | /* | |
3618 | * We must not cross into another context: | |
3619 | */ | |
3620 | if (prev_hlock->irq_context != hlock->irq_context) { | |
3621 | ret = NULL; | |
3622 | break; | |
3623 | } | |
3624 | if (match_held_lock(hlock, lock)) { | |
3625 | ret = hlock; | |
3626 | break; | |
3627 | } | |
3628 | } | |
3629 | ||
3630 | out: | |
3631 | *idx = i; | |
3632 | return ret; | |
3633 | } | |
3634 | ||
e969970b O |
3635 | static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, |
3636 | int idx) | |
3637 | { | |
3638 | struct held_lock *hlock; | |
3639 | ||
3640 | for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) { | |
3641 | if (!__lock_acquire(hlock->instance, | |
3642 | hlock_class(hlock)->subclass, | |
3643 | hlock->trylock, | |
3644 | hlock->read, hlock->check, | |
3645 | hlock->hardirqs_off, | |
3646 | hlock->nest_lock, hlock->acquire_ip, | |
3647 | hlock->references, hlock->pin_count)) | |
3648 | return 1; | |
3649 | } | |
3650 | return 0; | |
3651 | } | |
3652 | ||
64aa348e | 3653 | static int |
00ef9f73 PZ |
3654 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3655 | struct lock_class_key *key, unsigned int subclass, | |
3656 | unsigned long ip) | |
64aa348e PZ |
3657 | { |
3658 | struct task_struct *curr = current; | |
41c2c5b8 | 3659 | struct held_lock *hlock; |
64aa348e PZ |
3660 | struct lock_class *class; |
3661 | unsigned int depth; | |
3662 | int i; | |
3663 | ||
3664 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3665 | /* |
3666 | * This function is about (re)setting the class of a held lock, | |
3667 | * yet we're not actually holding any locks. Naughty user! | |
3668 | */ | |
64aa348e PZ |
3669 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3670 | return 0; | |
3671 | ||
41c2c5b8 O |
3672 | hlock = find_held_lock(curr, lock, depth, &i); |
3673 | if (!hlock) | |
3674 | return print_unlock_imbalance_bug(curr, lock, ip); | |
64aa348e | 3675 | |
00ef9f73 | 3676 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3677 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3678 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3679 | |
3680 | curr->lockdep_depth = i; | |
3681 | curr->curr_chain_key = hlock->prev_chain_key; | |
3682 | ||
e969970b O |
3683 | if (reacquire_held_locks(curr, depth, i)) |
3684 | return 0; | |
64aa348e | 3685 | |
0119fee4 PZ |
3686 | /* |
3687 | * I took it apart and put it back together again, except now I have | |
3688 | * these 'spare' parts.. where shall I put them. | |
3689 | */ | |
64aa348e PZ |
3690 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3691 | return 0; | |
3692 | return 1; | |
3693 | } | |
3694 | ||
6419c4af O |
3695 | static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
3696 | { | |
3697 | struct task_struct *curr = current; | |
3698 | struct held_lock *hlock; | |
3699 | unsigned int depth; | |
3700 | int i; | |
3701 | ||
3702 | depth = curr->lockdep_depth; | |
3703 | /* | |
3704 | * This function is about (re)setting the class of a held lock, | |
3705 | * yet we're not actually holding any locks. Naughty user! | |
3706 | */ | |
3707 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3708 | return 0; | |
3709 | ||
3710 | hlock = find_held_lock(curr, lock, depth, &i); | |
3711 | if (!hlock) | |
3712 | return print_unlock_imbalance_bug(curr, lock, ip); | |
3713 | ||
3714 | curr->lockdep_depth = i; | |
3715 | curr->curr_chain_key = hlock->prev_chain_key; | |
3716 | ||
3717 | WARN(hlock->read, "downgrading a read lock"); | |
3718 | hlock->read = 1; | |
3719 | hlock->acquire_ip = ip; | |
3720 | ||
3721 | if (reacquire_held_locks(curr, depth, i)) | |
3722 | return 0; | |
3723 | ||
3724 | /* | |
3725 | * I took it apart and put it back together again, except now I have | |
3726 | * these 'spare' parts.. where shall I put them. | |
3727 | */ | |
3728 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
3729 | return 0; | |
3730 | return 1; | |
3731 | } | |
3732 | ||
fbb9ce95 | 3733 | /* |
e0f56fd7 PZ |
3734 | * Remove the lock to the list of currently held locks - this gets |
3735 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3736 | * mutex_lock_interruptible()). | |
3737 | * | |
3738 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
3739 | */ |
3740 | static int | |
e0f56fd7 | 3741 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
fbb9ce95 | 3742 | { |
e0f56fd7 | 3743 | struct task_struct *curr = current; |
41c2c5b8 | 3744 | struct held_lock *hlock; |
fbb9ce95 | 3745 | unsigned int depth; |
b09be676 | 3746 | int ret, i; |
fbb9ce95 | 3747 | |
e0f56fd7 PZ |
3748 | if (unlikely(!debug_locks)) |
3749 | return 0; | |
3750 | ||
b09be676 BP |
3751 | ret = lock_release_crosslock(lock); |
3752 | /* | |
3753 | * 2 means normal release operations are needed. Otherwise, it's | |
3754 | * ok just to return with '0:fail, 1:success'. | |
3755 | */ | |
3756 | if (ret != 2) | |
3757 | return ret; | |
3758 | ||
fbb9ce95 | 3759 | depth = curr->lockdep_depth; |
0119fee4 PZ |
3760 | /* |
3761 | * So we're all set to release this lock.. wait what lock? We don't | |
3762 | * own any locks, you've been drinking again? | |
3763 | */ | |
e0f56fd7 PZ |
3764 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
3765 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3766 | |
e0f56fd7 PZ |
3767 | /* |
3768 | * Check whether the lock exists in the current stack | |
3769 | * of held locks: | |
3770 | */ | |
41c2c5b8 O |
3771 | hlock = find_held_lock(curr, lock, depth, &i); |
3772 | if (!hlock) | |
3773 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3774 | |
bb97a91e PZ |
3775 | if (hlock->instance == lock) |
3776 | lock_release_holdtime(hlock); | |
3777 | ||
a24fc60d PZ |
3778 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
3779 | ||
bb97a91e PZ |
3780 | if (hlock->references) { |
3781 | hlock->references--; | |
3782 | if (hlock->references) { | |
3783 | /* | |
3784 | * We had, and after removing one, still have | |
3785 | * references, the current lock stack is still | |
3786 | * valid. We're done! | |
3787 | */ | |
3788 | return 1; | |
3789 | } | |
3790 | } | |
f20786ff | 3791 | |
fbb9ce95 IM |
3792 | /* |
3793 | * We have the right lock to unlock, 'hlock' points to it. | |
3794 | * Now we remove it from the stack, and add back the other | |
3795 | * entries (if any), recalculating the hash along the way: | |
3796 | */ | |
bb97a91e | 3797 | |
fbb9ce95 IM |
3798 | curr->lockdep_depth = i; |
3799 | curr->curr_chain_key = hlock->prev_chain_key; | |
3800 | ||
e969970b O |
3801 | if (reacquire_held_locks(curr, depth, i + 1)) |
3802 | return 0; | |
fbb9ce95 | 3803 | |
0119fee4 PZ |
3804 | /* |
3805 | * We had N bottles of beer on the wall, we drank one, but now | |
3806 | * there's not N-1 bottles of beer left on the wall... | |
3807 | */ | |
fbb9ce95 IM |
3808 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3809 | return 0; | |
f20786ff | 3810 | |
fbb9ce95 IM |
3811 | return 1; |
3812 | } | |
3813 | ||
f8319483 | 3814 | static int __lock_is_held(struct lockdep_map *lock, int read) |
fbb9ce95 | 3815 | { |
f607c668 PZ |
3816 | struct task_struct *curr = current; |
3817 | int i; | |
fbb9ce95 | 3818 | |
f607c668 | 3819 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 3820 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 3821 | |
f8319483 PZ |
3822 | if (match_held_lock(hlock, lock)) { |
3823 | if (read == -1 || hlock->read == read) | |
3824 | return 1; | |
3825 | ||
3826 | return 0; | |
3827 | } | |
f607c668 | 3828 | } |
f20786ff | 3829 | |
f607c668 | 3830 | return 0; |
fbb9ce95 IM |
3831 | } |
3832 | ||
e7904a28 PZ |
3833 | static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) |
3834 | { | |
3835 | struct pin_cookie cookie = NIL_COOKIE; | |
3836 | struct task_struct *curr = current; | |
3837 | int i; | |
3838 | ||
3839 | if (unlikely(!debug_locks)) | |
3840 | return cookie; | |
3841 | ||
3842 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3843 | struct held_lock *hlock = curr->held_locks + i; | |
3844 | ||
3845 | if (match_held_lock(hlock, lock)) { | |
3846 | /* | |
3847 | * Grab 16bits of randomness; this is sufficient to not | |
3848 | * be guessable and still allows some pin nesting in | |
3849 | * our u32 pin_count. | |
3850 | */ | |
3851 | cookie.val = 1 + (prandom_u32() >> 16); | |
3852 | hlock->pin_count += cookie.val; | |
3853 | return cookie; | |
3854 | } | |
3855 | } | |
3856 | ||
3857 | WARN(1, "pinning an unheld lock\n"); | |
3858 | return cookie; | |
3859 | } | |
3860 | ||
3861 | static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
fbb9ce95 IM |
3862 | { |
3863 | struct task_struct *curr = current; | |
a24fc60d | 3864 | int i; |
fbb9ce95 | 3865 | |
a24fc60d | 3866 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
3867 | return; |
3868 | ||
a24fc60d PZ |
3869 | for (i = 0; i < curr->lockdep_depth; i++) { |
3870 | struct held_lock *hlock = curr->held_locks + i; | |
3871 | ||
3872 | if (match_held_lock(hlock, lock)) { | |
e7904a28 | 3873 | hlock->pin_count += cookie.val; |
fbb9ce95 | 3874 | return; |
a24fc60d | 3875 | } |
fbb9ce95 IM |
3876 | } |
3877 | ||
a24fc60d | 3878 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
3879 | } |
3880 | ||
e7904a28 | 3881 | static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
f607c668 PZ |
3882 | { |
3883 | struct task_struct *curr = current; | |
3884 | int i; | |
3885 | ||
a24fc60d PZ |
3886 | if (unlikely(!debug_locks)) |
3887 | return; | |
3888 | ||
f607c668 | 3889 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
3890 | struct held_lock *hlock = curr->held_locks + i; |
3891 | ||
a24fc60d PZ |
3892 | if (match_held_lock(hlock, lock)) { |
3893 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
3894 | return; | |
3895 | ||
e7904a28 PZ |
3896 | hlock->pin_count -= cookie.val; |
3897 | ||
3898 | if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n")) | |
3899 | hlock->pin_count = 0; | |
3900 | ||
a24fc60d PZ |
3901 | return; |
3902 | } | |
f607c668 PZ |
3903 | } |
3904 | ||
a24fc60d | 3905 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
3906 | } |
3907 | ||
fbb9ce95 IM |
3908 | /* |
3909 | * Check whether we follow the irq-flags state precisely: | |
3910 | */ | |
1d09daa5 | 3911 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3912 | { |
992860e9 IM |
3913 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3914 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3915 | if (!debug_locks) |
3916 | return; | |
3917 | ||
5f9fa8a6 IM |
3918 | if (irqs_disabled_flags(flags)) { |
3919 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3920 | printk("possible reason: unannotated irqs-off.\n"); | |
3921 | } | |
3922 | } else { | |
3923 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3924 | printk("possible reason: unannotated irqs-on.\n"); | |
3925 | } | |
3926 | } | |
fbb9ce95 IM |
3927 | |
3928 | /* | |
3929 | * We dont accurately track softirq state in e.g. | |
3930 | * hardirq contexts (such as on 4KSTACKS), so only | |
3931 | * check if not in hardirq contexts: | |
3932 | */ | |
3933 | if (!hardirq_count()) { | |
0119fee4 PZ |
3934 | if (softirq_count()) { |
3935 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3936 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3937 | } else { |
3938 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3939 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3940 | } |
fbb9ce95 IM |
3941 | } |
3942 | ||
3943 | if (!debug_locks) | |
3944 | print_irqtrace_events(current); | |
3945 | #endif | |
3946 | } | |
3947 | ||
00ef9f73 PZ |
3948 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3949 | struct lock_class_key *key, unsigned int subclass, | |
3950 | unsigned long ip) | |
64aa348e PZ |
3951 | { |
3952 | unsigned long flags; | |
3953 | ||
3954 | if (unlikely(current->lockdep_recursion)) | |
3955 | return; | |
3956 | ||
3957 | raw_local_irq_save(flags); | |
3958 | current->lockdep_recursion = 1; | |
3959 | check_flags(flags); | |
00ef9f73 | 3960 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3961 | check_chain_key(current); |
3962 | current->lockdep_recursion = 0; | |
3963 | raw_local_irq_restore(flags); | |
3964 | } | |
00ef9f73 | 3965 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3966 | |
6419c4af O |
3967 | void lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
3968 | { | |
3969 | unsigned long flags; | |
3970 | ||
3971 | if (unlikely(current->lockdep_recursion)) | |
3972 | return; | |
3973 | ||
3974 | raw_local_irq_save(flags); | |
3975 | current->lockdep_recursion = 1; | |
3976 | check_flags(flags); | |
3977 | if (__lock_downgrade(lock, ip)) | |
3978 | check_chain_key(current); | |
3979 | current->lockdep_recursion = 0; | |
3980 | raw_local_irq_restore(flags); | |
3981 | } | |
3982 | EXPORT_SYMBOL_GPL(lock_downgrade); | |
3983 | ||
fbb9ce95 IM |
3984 | /* |
3985 | * We are not always called with irqs disabled - do that here, | |
3986 | * and also avoid lockdep recursion: | |
3987 | */ | |
1d09daa5 | 3988 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3989 | int trylock, int read, int check, |
3990 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3991 | { |
3992 | unsigned long flags; | |
3993 | ||
3994 | if (unlikely(current->lockdep_recursion)) | |
3995 | return; | |
3996 | ||
3997 | raw_local_irq_save(flags); | |
3998 | check_flags(flags); | |
3999 | ||
4000 | current->lockdep_recursion = 1; | |
db2c4c77 | 4001 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 4002 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 4003 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
4004 | current->lockdep_recursion = 0; |
4005 | raw_local_irq_restore(flags); | |
4006 | } | |
fbb9ce95 IM |
4007 | EXPORT_SYMBOL_GPL(lock_acquire); |
4008 | ||
1d09daa5 | 4009 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 4010 | unsigned long ip) |
fbb9ce95 IM |
4011 | { |
4012 | unsigned long flags; | |
4013 | ||
4014 | if (unlikely(current->lockdep_recursion)) | |
4015 | return; | |
4016 | ||
4017 | raw_local_irq_save(flags); | |
4018 | check_flags(flags); | |
4019 | current->lockdep_recursion = 1; | |
93135439 | 4020 | trace_lock_release(lock, ip); |
e0f56fd7 PZ |
4021 | if (__lock_release(lock, nested, ip)) |
4022 | check_chain_key(current); | |
fbb9ce95 IM |
4023 | current->lockdep_recursion = 0; |
4024 | raw_local_irq_restore(flags); | |
4025 | } | |
fbb9ce95 IM |
4026 | EXPORT_SYMBOL_GPL(lock_release); |
4027 | ||
f8319483 | 4028 | int lock_is_held_type(struct lockdep_map *lock, int read) |
f607c668 PZ |
4029 | { |
4030 | unsigned long flags; | |
4031 | int ret = 0; | |
4032 | ||
4033 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 4034 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
4035 | |
4036 | raw_local_irq_save(flags); | |
4037 | check_flags(flags); | |
4038 | ||
4039 | current->lockdep_recursion = 1; | |
f8319483 | 4040 | ret = __lock_is_held(lock, read); |
f607c668 PZ |
4041 | current->lockdep_recursion = 0; |
4042 | raw_local_irq_restore(flags); | |
4043 | ||
4044 | return ret; | |
4045 | } | |
f8319483 | 4046 | EXPORT_SYMBOL_GPL(lock_is_held_type); |
f607c668 | 4047 | |
e7904a28 | 4048 | struct pin_cookie lock_pin_lock(struct lockdep_map *lock) |
a24fc60d | 4049 | { |
e7904a28 | 4050 | struct pin_cookie cookie = NIL_COOKIE; |
a24fc60d PZ |
4051 | unsigned long flags; |
4052 | ||
4053 | if (unlikely(current->lockdep_recursion)) | |
e7904a28 | 4054 | return cookie; |
a24fc60d PZ |
4055 | |
4056 | raw_local_irq_save(flags); | |
4057 | check_flags(flags); | |
4058 | ||
4059 | current->lockdep_recursion = 1; | |
e7904a28 | 4060 | cookie = __lock_pin_lock(lock); |
a24fc60d PZ |
4061 | current->lockdep_recursion = 0; |
4062 | raw_local_irq_restore(flags); | |
e7904a28 PZ |
4063 | |
4064 | return cookie; | |
a24fc60d PZ |
4065 | } |
4066 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
4067 | ||
e7904a28 PZ |
4068 | void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
4069 | { | |
4070 | unsigned long flags; | |
4071 | ||
4072 | if (unlikely(current->lockdep_recursion)) | |
4073 | return; | |
4074 | ||
4075 | raw_local_irq_save(flags); | |
4076 | check_flags(flags); | |
4077 | ||
4078 | current->lockdep_recursion = 1; | |
4079 | __lock_repin_lock(lock, cookie); | |
4080 | current->lockdep_recursion = 0; | |
4081 | raw_local_irq_restore(flags); | |
4082 | } | |
4083 | EXPORT_SYMBOL_GPL(lock_repin_lock); | |
4084 | ||
4085 | void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) | |
a24fc60d PZ |
4086 | { |
4087 | unsigned long flags; | |
4088 | ||
4089 | if (unlikely(current->lockdep_recursion)) | |
4090 | return; | |
4091 | ||
4092 | raw_local_irq_save(flags); | |
4093 | check_flags(flags); | |
4094 | ||
4095 | current->lockdep_recursion = 1; | |
e7904a28 | 4096 | __lock_unpin_lock(lock, cookie); |
a24fc60d PZ |
4097 | current->lockdep_recursion = 0; |
4098 | raw_local_irq_restore(flags); | |
4099 | } | |
4100 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
4101 | ||
f20786ff PZ |
4102 | #ifdef CONFIG_LOCK_STAT |
4103 | static int | |
4104 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
4105 | unsigned long ip) | |
4106 | { | |
4107 | if (!debug_locks_off()) | |
4108 | return 0; | |
4109 | if (debug_locks_silent) | |
4110 | return 0; | |
4111 | ||
681fbec8 | 4112 | pr_warn("\n"); |
a5dd63ef PM |
4113 | pr_warn("=================================\n"); |
4114 | pr_warn("WARNING: bad contention detected!\n"); | |
fbdc4b9a | 4115 | print_kernel_ident(); |
a5dd63ef | 4116 | pr_warn("---------------------------------\n"); |
681fbec8 | 4117 | pr_warn("%s/%d is trying to contend lock (", |
ba25f9dc | 4118 | curr->comm, task_pid_nr(curr)); |
f20786ff | 4119 | print_lockdep_cache(lock); |
681fbec8 | 4120 | pr_cont(") at:\n"); |
f20786ff | 4121 | print_ip_sym(ip); |
681fbec8 PM |
4122 | pr_warn("but there are no locks held!\n"); |
4123 | pr_warn("\nother info that might help us debug this:\n"); | |
f20786ff PZ |
4124 | lockdep_print_held_locks(curr); |
4125 | ||
681fbec8 | 4126 | pr_warn("\nstack backtrace:\n"); |
f20786ff PZ |
4127 | dump_stack(); |
4128 | ||
4129 | return 0; | |
4130 | } | |
4131 | ||
4132 | static void | |
4133 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4134 | { | |
4135 | struct task_struct *curr = current; | |
41c2c5b8 | 4136 | struct held_lock *hlock; |
f20786ff PZ |
4137 | struct lock_class_stats *stats; |
4138 | unsigned int depth; | |
c7e78cff | 4139 | int i, contention_point, contending_point; |
f20786ff PZ |
4140 | |
4141 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4142 | /* |
4143 | * Whee, we contended on this lock, except it seems we're not | |
4144 | * actually trying to acquire anything much at all.. | |
4145 | */ | |
f20786ff PZ |
4146 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4147 | return; | |
4148 | ||
41c2c5b8 O |
4149 | hlock = find_held_lock(curr, lock, depth, &i); |
4150 | if (!hlock) { | |
4151 | print_lock_contention_bug(curr, lock, ip); | |
4152 | return; | |
f20786ff | 4153 | } |
f20786ff | 4154 | |
bb97a91e PZ |
4155 | if (hlock->instance != lock) |
4156 | return; | |
4157 | ||
3365e779 | 4158 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 4159 | |
c7e78cff PZ |
4160 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
4161 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
4162 | lock->ip); | |
f20786ff | 4163 | |
f82b217e | 4164 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
4165 | if (contention_point < LOCKSTAT_POINTS) |
4166 | stats->contention_point[contention_point]++; | |
4167 | if (contending_point < LOCKSTAT_POINTS) | |
4168 | stats->contending_point[contending_point]++; | |
96645678 PZ |
4169 | if (lock->cpu != smp_processor_id()) |
4170 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
4171 | put_lock_stats(stats); |
4172 | } | |
4173 | ||
4174 | static void | |
c7e78cff | 4175 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4176 | { |
4177 | struct task_struct *curr = current; | |
41c2c5b8 | 4178 | struct held_lock *hlock; |
f20786ff PZ |
4179 | struct lock_class_stats *stats; |
4180 | unsigned int depth; | |
3365e779 | 4181 | u64 now, waittime = 0; |
96645678 | 4182 | int i, cpu; |
f20786ff PZ |
4183 | |
4184 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
4185 | /* |
4186 | * Yay, we acquired ownership of this lock we didn't try to | |
4187 | * acquire, how the heck did that happen? | |
4188 | */ | |
f20786ff PZ |
4189 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
4190 | return; | |
4191 | ||
41c2c5b8 O |
4192 | hlock = find_held_lock(curr, lock, depth, &i); |
4193 | if (!hlock) { | |
4194 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
4195 | return; | |
f20786ff | 4196 | } |
f20786ff | 4197 | |
bb97a91e PZ |
4198 | if (hlock->instance != lock) |
4199 | return; | |
4200 | ||
96645678 PZ |
4201 | cpu = smp_processor_id(); |
4202 | if (hlock->waittime_stamp) { | |
3365e779 | 4203 | now = lockstat_clock(); |
96645678 PZ |
4204 | waittime = now - hlock->waittime_stamp; |
4205 | hlock->holdtime_stamp = now; | |
4206 | } | |
f20786ff | 4207 | |
883a2a31 | 4208 | trace_lock_acquired(lock, ip); |
2062501a | 4209 | |
f82b217e | 4210 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
4211 | if (waittime) { |
4212 | if (hlock->read) | |
4213 | lock_time_inc(&stats->read_waittime, waittime); | |
4214 | else | |
4215 | lock_time_inc(&stats->write_waittime, waittime); | |
4216 | } | |
4217 | if (lock->cpu != cpu) | |
4218 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 4219 | put_lock_stats(stats); |
96645678 PZ |
4220 | |
4221 | lock->cpu = cpu; | |
c7e78cff | 4222 | lock->ip = ip; |
f20786ff PZ |
4223 | } |
4224 | ||
4225 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
4226 | { | |
4227 | unsigned long flags; | |
4228 | ||
4229 | if (unlikely(!lock_stat)) | |
4230 | return; | |
4231 | ||
4232 | if (unlikely(current->lockdep_recursion)) | |
4233 | return; | |
4234 | ||
4235 | raw_local_irq_save(flags); | |
4236 | check_flags(flags); | |
4237 | current->lockdep_recursion = 1; | |
db2c4c77 | 4238 | trace_lock_contended(lock, ip); |
f20786ff PZ |
4239 | __lock_contended(lock, ip); |
4240 | current->lockdep_recursion = 0; | |
4241 | raw_local_irq_restore(flags); | |
4242 | } | |
4243 | EXPORT_SYMBOL_GPL(lock_contended); | |
4244 | ||
c7e78cff | 4245 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
4246 | { |
4247 | unsigned long flags; | |
4248 | ||
4249 | if (unlikely(!lock_stat)) | |
4250 | return; | |
4251 | ||
4252 | if (unlikely(current->lockdep_recursion)) | |
4253 | return; | |
4254 | ||
4255 | raw_local_irq_save(flags); | |
4256 | check_flags(flags); | |
4257 | current->lockdep_recursion = 1; | |
c7e78cff | 4258 | __lock_acquired(lock, ip); |
f20786ff PZ |
4259 | current->lockdep_recursion = 0; |
4260 | raw_local_irq_restore(flags); | |
4261 | } | |
4262 | EXPORT_SYMBOL_GPL(lock_acquired); | |
4263 | #endif | |
4264 | ||
fbb9ce95 IM |
4265 | /* |
4266 | * Used by the testsuite, sanitize the validator state | |
4267 | * after a simulated failure: | |
4268 | */ | |
4269 | ||
4270 | void lockdep_reset(void) | |
4271 | { | |
4272 | unsigned long flags; | |
23d95a03 | 4273 | int i; |
fbb9ce95 IM |
4274 | |
4275 | raw_local_irq_save(flags); | |
4276 | current->curr_chain_key = 0; | |
4277 | current->lockdep_depth = 0; | |
4278 | current->lockdep_recursion = 0; | |
4279 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
4280 | nr_hardirq_chains = 0; | |
4281 | nr_softirq_chains = 0; | |
4282 | nr_process_chains = 0; | |
4283 | debug_locks = 1; | |
23d95a03 | 4284 | for (i = 0; i < CHAINHASH_SIZE; i++) |
a63f38cc | 4285 | INIT_HLIST_HEAD(chainhash_table + i); |
fbb9ce95 IM |
4286 | raw_local_irq_restore(flags); |
4287 | } | |
4288 | ||
4289 | static void zap_class(struct lock_class *class) | |
4290 | { | |
4291 | int i; | |
4292 | ||
4293 | /* | |
4294 | * Remove all dependencies this lock is | |
4295 | * involved in: | |
4296 | */ | |
4297 | for (i = 0; i < nr_list_entries; i++) { | |
4298 | if (list_entries[i].class == class) | |
4299 | list_del_rcu(&list_entries[i].entry); | |
4300 | } | |
4301 | /* | |
4302 | * Unhash the class and remove it from the all_lock_classes list: | |
4303 | */ | |
a63f38cc | 4304 | hlist_del_rcu(&class->hash_entry); |
fbb9ce95 IM |
4305 | list_del_rcu(&class->lock_entry); |
4306 | ||
cee34d88 PZ |
4307 | RCU_INIT_POINTER(class->key, NULL); |
4308 | RCU_INIT_POINTER(class->name, NULL); | |
fbb9ce95 IM |
4309 | } |
4310 | ||
fabe874a | 4311 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
4312 | { |
4313 | return addr >= start && addr < start + size; | |
4314 | } | |
4315 | ||
35a9393c PZ |
4316 | /* |
4317 | * Used in module.c to remove lock classes from memory that is going to be | |
4318 | * freed; and possibly re-used by other modules. | |
4319 | * | |
4320 | * We will have had one sync_sched() before getting here, so we're guaranteed | |
4321 | * nobody will look up these exact classes -- they're properly dead but still | |
4322 | * allocated. | |
4323 | */ | |
fbb9ce95 IM |
4324 | void lockdep_free_key_range(void *start, unsigned long size) |
4325 | { | |
35a9393c | 4326 | struct lock_class *class; |
a63f38cc | 4327 | struct hlist_head *head; |
fbb9ce95 IM |
4328 | unsigned long flags; |
4329 | int i; | |
5a26db5b | 4330 | int locked; |
fbb9ce95 IM |
4331 | |
4332 | raw_local_irq_save(flags); | |
5a26db5b | 4333 | locked = graph_lock(); |
fbb9ce95 IM |
4334 | |
4335 | /* | |
4336 | * Unhash all classes that were created by this module: | |
4337 | */ | |
4338 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
4339 | head = classhash_table + i; | |
a63f38cc | 4340 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
fbb9ce95 IM |
4341 | if (within(class->key, start, size)) |
4342 | zap_class(class); | |
fabe874a AV |
4343 | else if (within(class->name, start, size)) |
4344 | zap_class(class); | |
4345 | } | |
fbb9ce95 IM |
4346 | } |
4347 | ||
5a26db5b NP |
4348 | if (locked) |
4349 | graph_unlock(); | |
fbb9ce95 | 4350 | raw_local_irq_restore(flags); |
35a9393c PZ |
4351 | |
4352 | /* | |
4353 | * Wait for any possible iterators from look_up_lock_class() to pass | |
4354 | * before continuing to free the memory they refer to. | |
4355 | * | |
4356 | * sync_sched() is sufficient because the read-side is IRQ disable. | |
4357 | */ | |
4358 | synchronize_sched(); | |
4359 | ||
4360 | /* | |
4361 | * XXX at this point we could return the resources to the pool; | |
4362 | * instead we leak them. We would need to change to bitmap allocators | |
4363 | * instead of the linear allocators we have now. | |
4364 | */ | |
fbb9ce95 IM |
4365 | } |
4366 | ||
4367 | void lockdep_reset_lock(struct lockdep_map *lock) | |
4368 | { | |
35a9393c | 4369 | struct lock_class *class; |
a63f38cc | 4370 | struct hlist_head *head; |
fbb9ce95 IM |
4371 | unsigned long flags; |
4372 | int i, j; | |
5a26db5b | 4373 | int locked; |
fbb9ce95 IM |
4374 | |
4375 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
4376 | |
4377 | /* | |
d6d897ce IM |
4378 | * Remove all classes this lock might have: |
4379 | */ | |
4380 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
4381 | /* | |
4382 | * If the class exists we look it up and zap it: | |
4383 | */ | |
4384 | class = look_up_lock_class(lock, j); | |
383776fa | 4385 | if (!IS_ERR_OR_NULL(class)) |
d6d897ce IM |
4386 | zap_class(class); |
4387 | } | |
4388 | /* | |
4389 | * Debug check: in the end all mapped classes should | |
4390 | * be gone. | |
fbb9ce95 | 4391 | */ |
5a26db5b | 4392 | locked = graph_lock(); |
fbb9ce95 IM |
4393 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
4394 | head = classhash_table + i; | |
a63f38cc | 4395 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
62016250 HM |
4396 | int match = 0; |
4397 | ||
4398 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
4399 | match |= class == lock->class_cache[j]; | |
4400 | ||
4401 | if (unlikely(match)) { | |
0119fee4 PZ |
4402 | if (debug_locks_off_graph_unlock()) { |
4403 | /* | |
4404 | * We all just reset everything, how did it match? | |
4405 | */ | |
74c383f1 | 4406 | WARN_ON(1); |
0119fee4 | 4407 | } |
d6d897ce | 4408 | goto out_restore; |
fbb9ce95 IM |
4409 | } |
4410 | } | |
4411 | } | |
5a26db5b NP |
4412 | if (locked) |
4413 | graph_unlock(); | |
d6d897ce IM |
4414 | |
4415 | out_restore: | |
fbb9ce95 IM |
4416 | raw_local_irq_restore(flags); |
4417 | } | |
4418 | ||
fbb9ce95 IM |
4419 | void __init lockdep_info(void) |
4420 | { | |
4421 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
4422 | ||
b0788caf | 4423 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
4424 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
4425 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 4426 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
4427 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
4428 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
4429 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
4430 | ||
4431 | printk(" memory used by lock dependency info: %lu kB\n", | |
4432 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
4433 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
4434 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
4435 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 4436 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 4437 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 4438 | + sizeof(struct circular_queue) |
4dd861d6 | 4439 | #endif |
90629209 | 4440 | ) / 1024 |
4dd861d6 | 4441 | ); |
fbb9ce95 IM |
4442 | |
4443 | printk(" per task-struct memory footprint: %lu bytes\n", | |
4444 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
fbb9ce95 IM |
4445 | } |
4446 | ||
fbb9ce95 IM |
4447 | static void |
4448 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 4449 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
4450 | { |
4451 | if (!debug_locks_off()) | |
4452 | return; | |
4453 | if (debug_locks_silent) | |
4454 | return; | |
4455 | ||
681fbec8 | 4456 | pr_warn("\n"); |
a5dd63ef PM |
4457 | pr_warn("=========================\n"); |
4458 | pr_warn("WARNING: held lock freed!\n"); | |
fbdc4b9a | 4459 | print_kernel_ident(); |
a5dd63ef | 4460 | pr_warn("-------------------------\n"); |
681fbec8 | 4461 | pr_warn("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 4462 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 4463 | print_lock(hlock); |
fbb9ce95 IM |
4464 | lockdep_print_held_locks(curr); |
4465 | ||
681fbec8 | 4466 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
4467 | dump_stack(); |
4468 | } | |
4469 | ||
54561783 ON |
4470 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4471 | const void* lock_from, unsigned long lock_len) | |
4472 | { | |
4473 | return lock_from + lock_len <= mem_from || | |
4474 | mem_from + mem_len <= lock_from; | |
4475 | } | |
4476 | ||
fbb9ce95 IM |
4477 | /* |
4478 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4479 | * is destroyed or reinitialized - this code checks whether there is | |
4480 | * any held lock in the memory range of <from> to <to>: | |
4481 | */ | |
4482 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4483 | { | |
fbb9ce95 IM |
4484 | struct task_struct *curr = current; |
4485 | struct held_lock *hlock; | |
4486 | unsigned long flags; | |
4487 | int i; | |
4488 | ||
4489 | if (unlikely(!debug_locks)) | |
4490 | return; | |
4491 | ||
4492 | local_irq_save(flags); | |
4493 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4494 | hlock = curr->held_locks + i; | |
4495 | ||
54561783 ON |
4496 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4497 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4498 | continue; |
4499 | ||
54561783 | 4500 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4501 | break; |
4502 | } | |
4503 | local_irq_restore(flags); | |
4504 | } | |
ed07536e | 4505 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 4506 | |
1b1d2fb4 | 4507 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
4508 | { |
4509 | if (!debug_locks_off()) | |
4510 | return; | |
4511 | if (debug_locks_silent) | |
4512 | return; | |
4513 | ||
681fbec8 | 4514 | pr_warn("\n"); |
a5dd63ef PM |
4515 | pr_warn("====================================\n"); |
4516 | pr_warn("WARNING: %s/%d still has locks held!\n", | |
1b1d2fb4 | 4517 | current->comm, task_pid_nr(current)); |
fbdc4b9a | 4518 | print_kernel_ident(); |
a5dd63ef | 4519 | pr_warn("------------------------------------\n"); |
1b1d2fb4 | 4520 | lockdep_print_held_locks(current); |
681fbec8 | 4521 | pr_warn("\nstack backtrace:\n"); |
fbb9ce95 IM |
4522 | dump_stack(); |
4523 | } | |
4524 | ||
1b1d2fb4 | 4525 | void debug_check_no_locks_held(void) |
fbb9ce95 | 4526 | { |
1b1d2fb4 CC |
4527 | if (unlikely(current->lockdep_depth > 0)) |
4528 | print_held_locks_bug(); | |
fbb9ce95 | 4529 | } |
1b1d2fb4 | 4530 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 4531 | |
8dce7a9a | 4532 | #ifdef __KERNEL__ |
fbb9ce95 IM |
4533 | void debug_show_all_locks(void) |
4534 | { | |
4535 | struct task_struct *g, *p; | |
4536 | int count = 10; | |
4537 | int unlock = 1; | |
4538 | ||
9c35dd7f | 4539 | if (unlikely(!debug_locks)) { |
681fbec8 | 4540 | pr_warn("INFO: lockdep is turned off.\n"); |
9c35dd7f JP |
4541 | return; |
4542 | } | |
681fbec8 | 4543 | pr_warn("\nShowing all locks held in the system:\n"); |
fbb9ce95 IM |
4544 | |
4545 | /* | |
4546 | * Here we try to get the tasklist_lock as hard as possible, | |
4547 | * if not successful after 2 seconds we ignore it (but keep | |
4548 | * trying). This is to enable a debug printout even if a | |
4549 | * tasklist_lock-holding task deadlocks or crashes. | |
4550 | */ | |
4551 | retry: | |
4552 | if (!read_trylock(&tasklist_lock)) { | |
4553 | if (count == 10) | |
681fbec8 | 4554 | pr_warn("hm, tasklist_lock locked, retrying... "); |
fbb9ce95 IM |
4555 | if (count) { |
4556 | count--; | |
681fbec8 | 4557 | pr_cont(" #%d", 10-count); |
fbb9ce95 IM |
4558 | mdelay(200); |
4559 | goto retry; | |
4560 | } | |
681fbec8 | 4561 | pr_cont(" ignoring it.\n"); |
fbb9ce95 | 4562 | unlock = 0; |
46fec7ac | 4563 | } else { |
4564 | if (count != 10) | |
681fbec8 | 4565 | pr_cont(" locked it.\n"); |
fbb9ce95 | 4566 | } |
fbb9ce95 IM |
4567 | |
4568 | do_each_thread(g, p) { | |
85684873 IM |
4569 | /* |
4570 | * It's not reliable to print a task's held locks | |
4571 | * if it's not sleeping (or if it's not the current | |
4572 | * task): | |
4573 | */ | |
4574 | if (p->state == TASK_RUNNING && p != current) | |
4575 | continue; | |
fbb9ce95 IM |
4576 | if (p->lockdep_depth) |
4577 | lockdep_print_held_locks(p); | |
4578 | if (!unlock) | |
4579 | if (read_trylock(&tasklist_lock)) | |
4580 | unlock = 1; | |
4581 | } while_each_thread(g, p); | |
4582 | ||
681fbec8 | 4583 | pr_warn("\n"); |
a5dd63ef | 4584 | pr_warn("=============================================\n\n"); |
fbb9ce95 IM |
4585 | |
4586 | if (unlock) | |
4587 | read_unlock(&tasklist_lock); | |
4588 | } | |
fbb9ce95 | 4589 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 4590 | #endif |
fbb9ce95 | 4591 | |
82a1fcb9 IM |
4592 | /* |
4593 | * Careful: only use this function if you are sure that | |
4594 | * the task cannot run in parallel! | |
4595 | */ | |
f1b499f0 | 4596 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4597 | { |
9c35dd7f JP |
4598 | if (unlikely(!debug_locks)) { |
4599 | printk("INFO: lockdep is turned off.\n"); | |
4600 | return; | |
4601 | } | |
fbb9ce95 IM |
4602 | lockdep_print_held_locks(task); |
4603 | } | |
fbb9ce95 | 4604 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 4605 | |
722a9f92 | 4606 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
4607 | { |
4608 | struct task_struct *curr = current; | |
4609 | ||
4610 | if (unlikely(curr->lockdep_depth)) { | |
4611 | if (!debug_locks_off()) | |
4612 | return; | |
681fbec8 | 4613 | pr_warn("\n"); |
a5dd63ef PM |
4614 | pr_warn("================================================\n"); |
4615 | pr_warn("WARNING: lock held when returning to user space!\n"); | |
fbdc4b9a | 4616 | print_kernel_ident(); |
a5dd63ef | 4617 | pr_warn("------------------------------------------------\n"); |
681fbec8 | 4618 | pr_warn("%s/%d is leaving the kernel with locks still held!\n", |
b351d164 PZ |
4619 | curr->comm, curr->pid); |
4620 | lockdep_print_held_locks(curr); | |
4621 | } | |
b09be676 BP |
4622 | |
4623 | /* | |
4624 | * The lock history for each syscall should be independent. So wipe the | |
4625 | * slate clean on return to userspace. | |
a10b5c56 BP |
4626 | * |
4627 | * crossrelease_hist_end() works well here even when getting here | |
4628 | * without starting (i.e. just after forking), because it rolls back | |
4629 | * the index to point to the last entry, which is already invalid. | |
b09be676 BP |
4630 | */ |
4631 | crossrelease_hist_end(XHLOCK_PROC); | |
e6f3faa7 | 4632 | crossrelease_hist_start(XHLOCK_PROC, false); |
b351d164 | 4633 | } |
0632eb3d | 4634 | |
b3fbab05 | 4635 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4636 | { |
4637 | struct task_struct *curr = current; | |
4638 | ||
2b3fc35f | 4639 | /* Note: the following can be executed concurrently, so be careful. */ |
681fbec8 | 4640 | pr_warn("\n"); |
a5dd63ef PM |
4641 | pr_warn("=============================\n"); |
4642 | pr_warn("WARNING: suspicious RCU usage\n"); | |
fbdc4b9a | 4643 | print_kernel_ident(); |
a5dd63ef | 4644 | pr_warn("-----------------------------\n"); |
681fbec8 PM |
4645 | pr_warn("%s:%d %s!\n", file, line, s); |
4646 | pr_warn("\nother info that might help us debug this:\n\n"); | |
4647 | pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n", | |
c5fdcec9 PM |
4648 | !rcu_lockdep_current_cpu_online() |
4649 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 4650 | : !rcu_is_watching() |
c5fdcec9 PM |
4651 | ? "RCU used illegally from idle CPU!\n" |
4652 | : "", | |
4653 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
4654 | |
4655 | /* | |
4656 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
4657 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
4658 | * considers that CPU to be in an "extended quiescent state", | |
4659 | * which means that RCU will be completely ignoring that CPU. | |
4660 | * Therefore, rcu_read_lock() and friends have absolutely no | |
4661 | * effect on a CPU running in that state. In other words, even if | |
4662 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
4663 | * delete data structures out from under it. RCU really has no | |
4664 | * choice here: we need to keep an RCU-free window in idle where | |
4665 | * the CPU may possibly enter into low power mode. This way we can | |
4666 | * notice an extended quiescent state to other CPUs that started a grace | |
4667 | * period. Otherwise we would delay any grace period as long as we run | |
4668 | * in the idle task. | |
4669 | * | |
4670 | * So complain bitterly if someone does call rcu_read_lock(), | |
4671 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
4672 | */ | |
5c173eb8 | 4673 | if (!rcu_is_watching()) |
681fbec8 | 4674 | pr_warn("RCU used illegally from extended quiescent state!\n"); |
0464e937 | 4675 | |
0632eb3d | 4676 | lockdep_print_held_locks(curr); |
681fbec8 | 4677 | pr_warn("\nstack backtrace:\n"); |
0632eb3d PM |
4678 | dump_stack(); |
4679 | } | |
b3fbab05 | 4680 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |
b09be676 BP |
4681 | |
4682 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE | |
4683 | ||
4684 | /* | |
4685 | * Crossrelease works by recording a lock history for each thread and | |
4686 | * connecting those historic locks that were taken after the | |
4687 | * wait_for_completion() in the complete() context. | |
4688 | * | |
4689 | * Task-A Task-B | |
4690 | * | |
4691 | * mutex_lock(&A); | |
4692 | * mutex_unlock(&A); | |
4693 | * | |
4694 | * wait_for_completion(&C); | |
4695 | * lock_acquire_crosslock(); | |
4696 | * atomic_inc_return(&cross_gen_id); | |
4697 | * | | |
4698 | * | mutex_lock(&B); | |
4699 | * | mutex_unlock(&B); | |
4700 | * | | |
4701 | * | complete(&C); | |
4702 | * `-- lock_commit_crosslock(); | |
4703 | * | |
4704 | * Which will then add a dependency between B and C. | |
4705 | */ | |
4706 | ||
4707 | #define xhlock(i) (current->xhlocks[(i) % MAX_XHLOCKS_NR]) | |
4708 | ||
4709 | /* | |
4710 | * Whenever a crosslock is held, cross_gen_id will be increased. | |
4711 | */ | |
4712 | static atomic_t cross_gen_id; /* Can be wrapped */ | |
4713 | ||
23f873d8 BP |
4714 | /* |
4715 | * Make an entry of the ring buffer invalid. | |
4716 | */ | |
4717 | static inline void invalidate_xhlock(struct hist_lock *xhlock) | |
4718 | { | |
4719 | /* | |
4720 | * Normally, xhlock->hlock.instance must be !NULL. | |
4721 | */ | |
4722 | xhlock->hlock.instance = NULL; | |
4723 | } | |
4724 | ||
b09be676 BP |
4725 | /* |
4726 | * Lock history stacks; we have 3 nested lock history stacks: | |
4727 | * | |
e6f3faa7 PZ |
4728 | * HARD(IRQ) |
4729 | * SOFT(IRQ) | |
4730 | * PROC(ess) | |
b09be676 | 4731 | * |
e6f3faa7 PZ |
4732 | * The thing is that once we complete a HARD/SOFT IRQ the future task locks |
4733 | * should not depend on any of the locks observed while running the IRQ. So | |
4734 | * what we do is rewind the history buffer and erase all our knowledge of that | |
4735 | * temporal event. | |
b09be676 | 4736 | * |
e6f3faa7 PZ |
4737 | * The PROCess one is special though; it is used to annotate independence |
4738 | * inside a task. | |
4739 | * | |
4740 | * Take for instance workqueues; each work is independent of the last. The | |
4741 | * completion of a future work does not depend on the completion of a past work | |
4742 | * (in general). Therefore we must not carry that (lock) dependency across | |
4743 | * works. | |
b09be676 BP |
4744 | * |
4745 | * This is true for many things; pretty much all kthreads fall into this | |
e6f3faa7 | 4746 | * pattern, where they have an invariant state and future completions do not |
b09be676 BP |
4747 | * depend on past completions. Its just that since they all have the 'same' |
4748 | * form -- the kthread does the same over and over -- it doesn't typically | |
4749 | * matter. | |
4750 | * | |
4751 | * The same is true for system-calls, once a system call is completed (we've | |
4752 | * returned to userspace) the next system call does not depend on the lock | |
4753 | * history of the previous system call. | |
e6f3faa7 PZ |
4754 | * |
4755 | * They key property for independence, this invariant state, is that it must be | |
4756 | * a point where we hold no locks and have no history. Because if we were to | |
4757 | * hold locks, the restore at _end() would not necessarily recover it's history | |
4758 | * entry. Similarly, independence per-definition means it does not depend on | |
4759 | * prior state. | |
b09be676 | 4760 | */ |
e6f3faa7 | 4761 | void crossrelease_hist_start(enum xhlock_context_t c, bool force) |
b09be676 | 4762 | { |
23f873d8 BP |
4763 | struct task_struct *cur = current; |
4764 | ||
e6f3faa7 PZ |
4765 | if (!cur->xhlocks) |
4766 | return; | |
4767 | ||
4768 | /* | |
4769 | * We call this at an invariant point, no current state, no history. | |
4770 | */ | |
4771 | if (c == XHLOCK_PROC) { | |
4772 | /* verified the former, ensure the latter */ | |
4773 | WARN_ON_ONCE(!force && cur->lockdep_depth); | |
4774 | invalidate_xhlock(&xhlock(cur->xhlock_idx)); | |
23f873d8 | 4775 | } |
e6f3faa7 PZ |
4776 | |
4777 | cur->xhlock_idx_hist[c] = cur->xhlock_idx; | |
4778 | cur->hist_id_save[c] = cur->hist_id; | |
b09be676 BP |
4779 | } |
4780 | ||
4781 | void crossrelease_hist_end(enum xhlock_context_t c) | |
4782 | { | |
23f873d8 BP |
4783 | struct task_struct *cur = current; |
4784 | ||
4785 | if (cur->xhlocks) { | |
4786 | unsigned int idx = cur->xhlock_idx_hist[c]; | |
4787 | struct hist_lock *h = &xhlock(idx); | |
4788 | ||
4789 | cur->xhlock_idx = idx; | |
4790 | ||
4791 | /* Check if the ring was overwritten. */ | |
4792 | if (h->hist_id != cur->hist_id_save[c]) | |
4793 | invalidate_xhlock(h); | |
4794 | } | |
b09be676 BP |
4795 | } |
4796 | ||
4797 | static int cross_lock(struct lockdep_map *lock) | |
4798 | { | |
4799 | return lock ? lock->cross : 0; | |
4800 | } | |
4801 | ||
4802 | /* | |
4803 | * This is needed to decide the relationship between wrapable variables. | |
4804 | */ | |
4805 | static inline int before(unsigned int a, unsigned int b) | |
4806 | { | |
4807 | return (int)(a - b) < 0; | |
4808 | } | |
4809 | ||
4810 | static inline struct lock_class *xhlock_class(struct hist_lock *xhlock) | |
4811 | { | |
4812 | return hlock_class(&xhlock->hlock); | |
4813 | } | |
4814 | ||
4815 | static inline struct lock_class *xlock_class(struct cross_lock *xlock) | |
4816 | { | |
4817 | return hlock_class(&xlock->hlock); | |
4818 | } | |
4819 | ||
4820 | /* | |
4821 | * Should we check a dependency with previous one? | |
4822 | */ | |
4823 | static inline int depend_before(struct held_lock *hlock) | |
4824 | { | |
4825 | return hlock->read != 2 && hlock->check && !hlock->trylock; | |
4826 | } | |
4827 | ||
4828 | /* | |
4829 | * Should we check a dependency with next one? | |
4830 | */ | |
4831 | static inline int depend_after(struct held_lock *hlock) | |
4832 | { | |
4833 | return hlock->read != 2 && hlock->check; | |
4834 | } | |
4835 | ||
4836 | /* | |
4837 | * Check if the xhlock is valid, which would be false if, | |
4838 | * | |
4839 | * 1. Has not used after initializaion yet. | |
23f873d8 | 4840 | * 2. Got invalidated. |
b09be676 BP |
4841 | * |
4842 | * Remind hist_lock is implemented as a ring buffer. | |
4843 | */ | |
4844 | static inline int xhlock_valid(struct hist_lock *xhlock) | |
4845 | { | |
4846 | /* | |
4847 | * xhlock->hlock.instance must be !NULL. | |
4848 | */ | |
4849 | return !!xhlock->hlock.instance; | |
4850 | } | |
4851 | ||
4852 | /* | |
4853 | * Record a hist_lock entry. | |
4854 | * | |
4855 | * Irq disable is only required. | |
4856 | */ | |
4857 | static void add_xhlock(struct held_lock *hlock) | |
4858 | { | |
4859 | unsigned int idx = ++current->xhlock_idx; | |
4860 | struct hist_lock *xhlock = &xhlock(idx); | |
4861 | ||
4862 | #ifdef CONFIG_DEBUG_LOCKDEP | |
4863 | /* | |
4864 | * This can be done locklessly because they are all task-local | |
4865 | * state, we must however ensure IRQs are disabled. | |
4866 | */ | |
4867 | WARN_ON_ONCE(!irqs_disabled()); | |
4868 | #endif | |
4869 | ||
4870 | /* Initialize hist_lock's members */ | |
4871 | xhlock->hlock = *hlock; | |
907dc16d | 4872 | xhlock->hist_id = ++current->hist_id; |
b09be676 BP |
4873 | |
4874 | xhlock->trace.nr_entries = 0; | |
4875 | xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; | |
4876 | xhlock->trace.entries = xhlock->trace_entries; | |
4877 | xhlock->trace.skip = 3; | |
4878 | save_stack_trace(&xhlock->trace); | |
4879 | } | |
4880 | ||
4881 | static inline int same_context_xhlock(struct hist_lock *xhlock) | |
4882 | { | |
4883 | return xhlock->hlock.irq_context == task_irq_context(current); | |
4884 | } | |
4885 | ||
4886 | /* | |
4887 | * This should be lockless as far as possible because this would be | |
4888 | * called very frequently. | |
4889 | */ | |
4890 | static void check_add_xhlock(struct held_lock *hlock) | |
4891 | { | |
4892 | /* | |
4893 | * Record a hist_lock, only in case that acquisitions ahead | |
4894 | * could depend on the held_lock. For example, if the held_lock | |
4895 | * is trylock then acquisitions ahead never depends on that. | |
4896 | * In that case, we don't need to record it. Just return. | |
4897 | */ | |
4898 | if (!current->xhlocks || !depend_before(hlock)) | |
4899 | return; | |
4900 | ||
4901 | add_xhlock(hlock); | |
4902 | } | |
4903 | ||
4904 | /* | |
4905 | * For crosslock. | |
4906 | */ | |
4907 | static int add_xlock(struct held_lock *hlock) | |
4908 | { | |
4909 | struct cross_lock *xlock; | |
4910 | unsigned int gen_id; | |
4911 | ||
4912 | if (!graph_lock()) | |
4913 | return 0; | |
4914 | ||
4915 | xlock = &((struct lockdep_map_cross *)hlock->instance)->xlock; | |
4916 | ||
28a903f6 BP |
4917 | /* |
4918 | * When acquisitions for a crosslock are overlapped, we use | |
4919 | * nr_acquire to perform commit for them, based on cross_gen_id | |
4920 | * of the first acquisition, which allows to add additional | |
4921 | * dependencies. | |
4922 | * | |
4923 | * Moreover, when no acquisition of a crosslock is in progress, | |
4924 | * we should not perform commit because the lock might not exist | |
4925 | * any more, which might cause incorrect memory access. So we | |
4926 | * have to track the number of acquisitions of a crosslock. | |
4927 | * | |
4928 | * depend_after() is necessary to initialize only the first | |
4929 | * valid xlock so that the xlock can be used on its commit. | |
4930 | */ | |
4931 | if (xlock->nr_acquire++ && depend_after(&xlock->hlock)) | |
4932 | goto unlock; | |
4933 | ||
b09be676 BP |
4934 | gen_id = (unsigned int)atomic_inc_return(&cross_gen_id); |
4935 | xlock->hlock = *hlock; | |
4936 | xlock->hlock.gen_id = gen_id; | |
28a903f6 | 4937 | unlock: |
b09be676 | 4938 | graph_unlock(); |
b09be676 BP |
4939 | return 1; |
4940 | } | |
4941 | ||
4942 | /* | |
4943 | * Called for both normal and crosslock acquires. Normal locks will be | |
4944 | * pushed on the hist_lock queue. Cross locks will record state and | |
4945 | * stop regular lock_acquire() to avoid being placed on the held_lock | |
4946 | * stack. | |
4947 | * | |
4948 | * Return: 0 - failure; | |
4949 | * 1 - crosslock, done; | |
4950 | * 2 - normal lock, continue to held_lock[] ops. | |
4951 | */ | |
4952 | static int lock_acquire_crosslock(struct held_lock *hlock) | |
4953 | { | |
4954 | /* | |
4955 | * CONTEXT 1 CONTEXT 2 | |
4956 | * --------- --------- | |
4957 | * lock A (cross) | |
4958 | * X = atomic_inc_return(&cross_gen_id) | |
4959 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
4960 | * Y = atomic_read_acquire(&cross_gen_id) | |
4961 | * lock B | |
4962 | * | |
4963 | * atomic_read_acquire() is for ordering between A and B, | |
4964 | * IOW, A happens before B, when CONTEXT 2 see Y >= X. | |
4965 | * | |
4966 | * Pairs with atomic_inc_return() in add_xlock(). | |
4967 | */ | |
4968 | hlock->gen_id = (unsigned int)atomic_read_acquire(&cross_gen_id); | |
4969 | ||
4970 | if (cross_lock(hlock->instance)) | |
4971 | return add_xlock(hlock); | |
4972 | ||
4973 | check_add_xhlock(hlock); | |
4974 | return 2; | |
4975 | } | |
4976 | ||
4977 | static int copy_trace(struct stack_trace *trace) | |
4978 | { | |
4979 | unsigned long *buf = stack_trace + nr_stack_trace_entries; | |
4980 | unsigned int max_nr = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
4981 | unsigned int nr = min(max_nr, trace->nr_entries); | |
4982 | ||
4983 | trace->nr_entries = nr; | |
4984 | memcpy(buf, trace->entries, nr * sizeof(trace->entries[0])); | |
4985 | trace->entries = buf; | |
4986 | nr_stack_trace_entries += nr; | |
4987 | ||
4988 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { | |
4989 | if (!debug_locks_off_graph_unlock()) | |
4990 | return 0; | |
4991 | ||
4992 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); | |
4993 | dump_stack(); | |
4994 | ||
4995 | return 0; | |
4996 | } | |
4997 | ||
4998 | return 1; | |
4999 | } | |
5000 | ||
5001 | static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock) | |
5002 | { | |
5003 | unsigned int xid, pid; | |
5004 | u64 chain_key; | |
5005 | ||
5006 | xid = xlock_class(xlock) - lock_classes; | |
5007 | chain_key = iterate_chain_key((u64)0, xid); | |
5008 | pid = xhlock_class(xhlock) - lock_classes; | |
5009 | chain_key = iterate_chain_key(chain_key, pid); | |
5010 | ||
5011 | if (lookup_chain_cache(chain_key)) | |
5012 | return 1; | |
5013 | ||
5014 | if (!add_chain_cache_classes(xid, pid, xhlock->hlock.irq_context, | |
5015 | chain_key)) | |
5016 | return 0; | |
5017 | ||
5018 | if (!check_prev_add(current, &xlock->hlock, &xhlock->hlock, 1, | |
5019 | &xhlock->trace, copy_trace)) | |
5020 | return 0; | |
5021 | ||
5022 | return 1; | |
5023 | } | |
5024 | ||
5025 | static void commit_xhlocks(struct cross_lock *xlock) | |
5026 | { | |
5027 | unsigned int cur = current->xhlock_idx; | |
23f873d8 | 5028 | unsigned int prev_hist_id = xhlock(cur).hist_id; |
b09be676 BP |
5029 | unsigned int i; |
5030 | ||
5031 | if (!graph_lock()) | |
5032 | return; | |
5033 | ||
28a903f6 BP |
5034 | if (xlock->nr_acquire) { |
5035 | for (i = 0; i < MAX_XHLOCKS_NR; i++) { | |
5036 | struct hist_lock *xhlock = &xhlock(cur - i); | |
b09be676 | 5037 | |
28a903f6 BP |
5038 | if (!xhlock_valid(xhlock)) |
5039 | break; | |
b09be676 | 5040 | |
28a903f6 BP |
5041 | if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id)) |
5042 | break; | |
b09be676 | 5043 | |
28a903f6 BP |
5044 | if (!same_context_xhlock(xhlock)) |
5045 | break; | |
b09be676 | 5046 | |
28a903f6 | 5047 | /* |
907dc16d BP |
5048 | * Filter out the cases where the ring buffer was |
5049 | * overwritten and the current entry has a bigger | |
5050 | * hist_id than the previous one, which is impossible | |
5051 | * otherwise: | |
28a903f6 | 5052 | */ |
907dc16d | 5053 | if (unlikely(before(prev_hist_id, xhlock->hist_id))) |
28a903f6 | 5054 | break; |
23f873d8 | 5055 | |
28a903f6 | 5056 | prev_hist_id = xhlock->hist_id; |
23f873d8 | 5057 | |
28a903f6 BP |
5058 | /* |
5059 | * commit_xhlock() returns 0 with graph_lock already | |
5060 | * released if fail. | |
5061 | */ | |
5062 | if (!commit_xhlock(xlock, xhlock)) | |
5063 | return; | |
5064 | } | |
b09be676 BP |
5065 | } |
5066 | ||
5067 | graph_unlock(); | |
5068 | } | |
5069 | ||
5070 | void lock_commit_crosslock(struct lockdep_map *lock) | |
5071 | { | |
5072 | struct cross_lock *xlock; | |
5073 | unsigned long flags; | |
5074 | ||
5075 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
5076 | return; | |
5077 | ||
5078 | if (!current->xhlocks) | |
5079 | return; | |
5080 | ||
5081 | /* | |
5082 | * Do commit hist_locks with the cross_lock, only in case that | |
5083 | * the cross_lock could depend on acquisitions after that. | |
5084 | * | |
5085 | * For example, if the cross_lock does not have the 'check' flag | |
5086 | * then we don't need to check dependencies and commit for that. | |
5087 | * Just skip it. In that case, of course, the cross_lock does | |
5088 | * not depend on acquisitions ahead, either. | |
5089 | * | |
5090 | * WARNING: Don't do that in add_xlock() in advance. When an | |
5091 | * acquisition context is different from the commit context, | |
5092 | * invalid(skipped) cross_lock might be accessed. | |
5093 | */ | |
5094 | if (!depend_after(&((struct lockdep_map_cross *)lock)->xlock.hlock)) | |
5095 | return; | |
5096 | ||
5097 | raw_local_irq_save(flags); | |
5098 | check_flags(flags); | |
5099 | current->lockdep_recursion = 1; | |
5100 | xlock = &((struct lockdep_map_cross *)lock)->xlock; | |
5101 | commit_xhlocks(xlock); | |
5102 | current->lockdep_recursion = 0; | |
5103 | raw_local_irq_restore(flags); | |
5104 | } | |
5105 | EXPORT_SYMBOL_GPL(lock_commit_crosslock); | |
5106 | ||
5107 | /* | |
28a903f6 BP |
5108 | * Return: 0 - failure; |
5109 | * 1 - crosslock, done; | |
b09be676 BP |
5110 | * 2 - normal lock, continue to held_lock[] ops. |
5111 | */ | |
5112 | static int lock_release_crosslock(struct lockdep_map *lock) | |
5113 | { | |
28a903f6 BP |
5114 | if (cross_lock(lock)) { |
5115 | if (!graph_lock()) | |
5116 | return 0; | |
5117 | ((struct lockdep_map_cross *)lock)->xlock.nr_acquire--; | |
5118 | graph_unlock(); | |
5119 | return 1; | |
5120 | } | |
5121 | return 2; | |
b09be676 BP |
5122 | } |
5123 | ||
5124 | static void cross_init(struct lockdep_map *lock, int cross) | |
5125 | { | |
28a903f6 BP |
5126 | if (cross) |
5127 | ((struct lockdep_map_cross *)lock)->xlock.nr_acquire = 0; | |
5128 | ||
b09be676 BP |
5129 | lock->cross = cross; |
5130 | ||
5131 | /* | |
5132 | * Crossrelease assumes that the ring buffer size of xhlocks | |
5133 | * is aligned with power of 2. So force it on build. | |
5134 | */ | |
5135 | BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCKS_NR - 1)); | |
5136 | } | |
5137 | ||
5138 | void lockdep_init_task(struct task_struct *task) | |
5139 | { | |
5140 | int i; | |
5141 | ||
5142 | task->xhlock_idx = UINT_MAX; | |
23f873d8 | 5143 | task->hist_id = 0; |
b09be676 | 5144 | |
23f873d8 | 5145 | for (i = 0; i < XHLOCK_CTX_NR; i++) { |
b09be676 | 5146 | task->xhlock_idx_hist[i] = UINT_MAX; |
23f873d8 BP |
5147 | task->hist_id_save[i] = 0; |
5148 | } | |
b09be676 BP |
5149 | |
5150 | task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR, | |
5151 | GFP_KERNEL); | |
5152 | } | |
5153 | ||
5154 | void lockdep_free_task(struct task_struct *task) | |
5155 | { | |
5156 | if (task->xhlocks) { | |
5157 | void *tmp = task->xhlocks; | |
5158 | /* Diable crossrelease for current */ | |
5159 | task->xhlocks = NULL; | |
5160 | kfree(tmp); | |
5161 | } | |
5162 | } | |
5163 | #endif |