Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
af012961 | 47 | |
fbb9ce95 IM |
48 | #include <asm/sections.h> |
49 | ||
50 | #include "lockdep_internals.h" | |
51 | ||
a8d154b0 | 52 | #define CREATE_TRACE_POINTS |
67178767 | 53 | #include <trace/events/lock.h> |
a8d154b0 | 54 | |
f20786ff PZ |
55 | #ifdef CONFIG_PROVE_LOCKING |
56 | int prove_locking = 1; | |
57 | module_param(prove_locking, int, 0644); | |
58 | #else | |
59 | #define prove_locking 0 | |
60 | #endif | |
61 | ||
62 | #ifdef CONFIG_LOCK_STAT | |
63 | int lock_stat = 1; | |
64 | module_param(lock_stat, int, 0644); | |
65 | #else | |
66 | #define lock_stat 0 | |
67 | #endif | |
68 | ||
fbb9ce95 | 69 | /* |
74c383f1 IM |
70 | * lockdep_lock: protects the lockdep graph, the hashes and the |
71 | * class/list/hash allocators. | |
fbb9ce95 IM |
72 | * |
73 | * This is one of the rare exceptions where it's justified | |
74 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 75 | * code to recurse back into the lockdep code... |
fbb9ce95 | 76 | */ |
edc35bd7 | 77 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
78 | |
79 | static int graph_lock(void) | |
80 | { | |
0199c4e6 | 81 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
82 | /* |
83 | * Make sure that if another CPU detected a bug while | |
84 | * walking the graph we dont change it (while the other | |
85 | * CPU is busy printing out stuff with the graph lock | |
86 | * dropped already) | |
87 | */ | |
88 | if (!debug_locks) { | |
0199c4e6 | 89 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
90 | return 0; |
91 | } | |
bb065afb SR |
92 | /* prevent any recursions within lockdep from causing deadlocks */ |
93 | current->lockdep_recursion++; | |
74c383f1 IM |
94 | return 1; |
95 | } | |
96 | ||
97 | static inline int graph_unlock(void) | |
98 | { | |
0199c4e6 | 99 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) |
381a2292 JP |
100 | return DEBUG_LOCKS_WARN_ON(1); |
101 | ||
bb065afb | 102 | current->lockdep_recursion--; |
0199c4e6 | 103 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
104 | return 0; |
105 | } | |
106 | ||
107 | /* | |
108 | * Turn lock debugging off and return with 0 if it was off already, | |
109 | * and also release the graph lock: | |
110 | */ | |
111 | static inline int debug_locks_off_graph_unlock(void) | |
112 | { | |
113 | int ret = debug_locks_off(); | |
114 | ||
0199c4e6 | 115 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
116 | |
117 | return ret; | |
118 | } | |
fbb9ce95 IM |
119 | |
120 | static int lockdep_initialized; | |
121 | ||
122 | unsigned long nr_list_entries; | |
af012961 | 123 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 124 | |
fbb9ce95 IM |
125 | /* |
126 | * All data structures here are protected by the global debug_lock. | |
127 | * | |
128 | * Mutex key structs only get allocated, once during bootup, and never | |
129 | * get freed - this significantly simplifies the debugging code. | |
130 | */ | |
131 | unsigned long nr_lock_classes; | |
132 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
133 | ||
f82b217e DJ |
134 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
135 | { | |
136 | if (!hlock->class_idx) { | |
137 | DEBUG_LOCKS_WARN_ON(1); | |
138 | return NULL; | |
139 | } | |
140 | return lock_classes + hlock->class_idx - 1; | |
141 | } | |
142 | ||
f20786ff | 143 | #ifdef CONFIG_LOCK_STAT |
1871e52c TH |
144 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
145 | cpu_lock_stats); | |
f20786ff | 146 | |
3365e779 PZ |
147 | static inline u64 lockstat_clock(void) |
148 | { | |
149 | return cpu_clock(smp_processor_id()); | |
150 | } | |
151 | ||
c7e78cff | 152 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
153 | { |
154 | int i; | |
155 | ||
c7e78cff PZ |
156 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
157 | if (points[i] == 0) { | |
158 | points[i] = ip; | |
f20786ff PZ |
159 | break; |
160 | } | |
c7e78cff | 161 | if (points[i] == ip) |
f20786ff PZ |
162 | break; |
163 | } | |
164 | ||
165 | return i; | |
166 | } | |
167 | ||
3365e779 | 168 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
169 | { |
170 | if (time > lt->max) | |
171 | lt->max = time; | |
172 | ||
109d71c6 | 173 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
174 | lt->min = time; |
175 | ||
176 | lt->total += time; | |
177 | lt->nr++; | |
178 | } | |
179 | ||
c46261de PZ |
180 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
181 | { | |
109d71c6 FR |
182 | if (!src->nr) |
183 | return; | |
184 | ||
185 | if (src->max > dst->max) | |
186 | dst->max = src->max; | |
187 | ||
188 | if (src->min < dst->min || !dst->nr) | |
189 | dst->min = src->min; | |
190 | ||
c46261de PZ |
191 | dst->total += src->total; |
192 | dst->nr += src->nr; | |
193 | } | |
194 | ||
195 | struct lock_class_stats lock_stats(struct lock_class *class) | |
196 | { | |
197 | struct lock_class_stats stats; | |
198 | int cpu, i; | |
199 | ||
200 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
201 | for_each_possible_cpu(cpu) { | |
202 | struct lock_class_stats *pcs = | |
1871e52c | 203 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
204 | |
205 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
206 | stats.contention_point[i] += pcs->contention_point[i]; | |
207 | ||
c7e78cff PZ |
208 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
209 | stats.contending_point[i] += pcs->contending_point[i]; | |
210 | ||
c46261de PZ |
211 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
212 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
213 | ||
214 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
215 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
216 | |
217 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
218 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
219 | } |
220 | ||
221 | return stats; | |
222 | } | |
223 | ||
224 | void clear_lock_stats(struct lock_class *class) | |
225 | { | |
226 | int cpu; | |
227 | ||
228 | for_each_possible_cpu(cpu) { | |
229 | struct lock_class_stats *cpu_stats = | |
1871e52c | 230 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
231 | |
232 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
233 | } | |
234 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 235 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
236 | } |
237 | ||
f20786ff PZ |
238 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
239 | { | |
1871e52c | 240 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
241 | } |
242 | ||
243 | static void put_lock_stats(struct lock_class_stats *stats) | |
244 | { | |
1871e52c | 245 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
246 | } |
247 | ||
248 | static void lock_release_holdtime(struct held_lock *hlock) | |
249 | { | |
250 | struct lock_class_stats *stats; | |
3365e779 | 251 | u64 holdtime; |
f20786ff PZ |
252 | |
253 | if (!lock_stat) | |
254 | return; | |
255 | ||
3365e779 | 256 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 257 | |
f82b217e | 258 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
259 | if (hlock->read) |
260 | lock_time_inc(&stats->read_holdtime, holdtime); | |
261 | else | |
262 | lock_time_inc(&stats->write_holdtime, holdtime); | |
263 | put_lock_stats(stats); | |
264 | } | |
265 | #else | |
266 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
267 | { | |
268 | } | |
269 | #endif | |
270 | ||
fbb9ce95 IM |
271 | /* |
272 | * We keep a global list of all lock classes. The list only grows, | |
273 | * never shrinks. The list is only accessed with the lockdep | |
274 | * spinlock lock held. | |
275 | */ | |
276 | LIST_HEAD(all_lock_classes); | |
277 | ||
278 | /* | |
279 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
280 | */ | |
281 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
282 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 283 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
284 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
285 | ||
286 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
287 | ||
fbb9ce95 IM |
288 | /* |
289 | * We put the lock dependency chains into a hash-table as well, to cache | |
290 | * their existence: | |
291 | */ | |
292 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
293 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 294 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
295 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
296 | ||
297 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
298 | ||
299 | /* | |
300 | * The hash key of the lock dependency chains is a hash itself too: | |
301 | * it's a hash of all locks taken up to that lock, including that lock. | |
302 | * It's a 64-bit hash, because it's important for the keys to be | |
303 | * unique. | |
304 | */ | |
305 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
306 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
307 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
308 | (key2)) |
309 | ||
1d09daa5 | 310 | void lockdep_off(void) |
fbb9ce95 IM |
311 | { |
312 | current->lockdep_recursion++; | |
313 | } | |
fbb9ce95 IM |
314 | EXPORT_SYMBOL(lockdep_off); |
315 | ||
1d09daa5 | 316 | void lockdep_on(void) |
fbb9ce95 IM |
317 | { |
318 | current->lockdep_recursion--; | |
319 | } | |
fbb9ce95 IM |
320 | EXPORT_SYMBOL(lockdep_on); |
321 | ||
fbb9ce95 IM |
322 | /* |
323 | * Debugging switches: | |
324 | */ | |
325 | ||
326 | #define VERBOSE 0 | |
33e94e96 | 327 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
328 | |
329 | #if VERBOSE | |
330 | # define HARDIRQ_VERBOSE 1 | |
331 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 332 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
333 | #else |
334 | # define HARDIRQ_VERBOSE 0 | |
335 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 336 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
337 | #endif |
338 | ||
cf40bd16 | 339 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
340 | /* |
341 | * Quick filtering for interesting events: | |
342 | */ | |
343 | static int class_filter(struct lock_class *class) | |
344 | { | |
f9829cce AK |
345 | #if 0 |
346 | /* Example */ | |
fbb9ce95 | 347 | if (class->name_version == 1 && |
f9829cce | 348 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
349 | return 1; |
350 | if (class->name_version == 1 && | |
f9829cce | 351 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 352 | return 1; |
f9829cce | 353 | #endif |
a6640897 IM |
354 | /* Filter everything else. 1 would be to allow everything else */ |
355 | return 0; | |
fbb9ce95 IM |
356 | } |
357 | #endif | |
358 | ||
359 | static int verbose(struct lock_class *class) | |
360 | { | |
361 | #if VERBOSE | |
362 | return class_filter(class); | |
363 | #endif | |
364 | return 0; | |
365 | } | |
366 | ||
fbb9ce95 IM |
367 | /* |
368 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 369 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
370 | */ |
371 | unsigned long nr_stack_trace_entries; | |
372 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
373 | ||
374 | static int save_trace(struct stack_trace *trace) | |
375 | { | |
376 | trace->nr_entries = 0; | |
377 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
378 | trace->entries = stack_trace + nr_stack_trace_entries; | |
379 | ||
5a1b3999 | 380 | trace->skip = 3; |
5a1b3999 | 381 | |
ab1b6f03 | 382 | save_stack_trace(trace); |
fbb9ce95 | 383 | |
4f84f433 PZ |
384 | /* |
385 | * Some daft arches put -1 at the end to indicate its a full trace. | |
386 | * | |
387 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
388 | * complete trace that maxes out the entries provided will be reported | |
389 | * as incomplete, friggin useless </rant> | |
390 | */ | |
ea5b41f9 LT |
391 | if (trace->nr_entries != 0 && |
392 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
393 | trace->nr_entries--; |
394 | ||
fbb9ce95 IM |
395 | trace->max_entries = trace->nr_entries; |
396 | ||
397 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 398 | |
4f84f433 | 399 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
400 | if (!debug_locks_off_graph_unlock()) |
401 | return 0; | |
402 | ||
403 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
404 | printk("turning off the locking correctness validator.\n"); | |
405 | dump_stack(); | |
406 | ||
fbb9ce95 IM |
407 | return 0; |
408 | } | |
409 | ||
410 | return 1; | |
411 | } | |
412 | ||
413 | unsigned int nr_hardirq_chains; | |
414 | unsigned int nr_softirq_chains; | |
415 | unsigned int nr_process_chains; | |
416 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
417 | |
418 | #ifdef CONFIG_DEBUG_LOCKDEP | |
419 | /* | |
420 | * We cannot printk in early bootup code. Not even early_printk() | |
421 | * might work. So we mark any initialization errors and printk | |
422 | * about it later on, in lockdep_info(). | |
423 | */ | |
424 | static int lockdep_init_error; | |
c71063c9 JB |
425 | static unsigned long lockdep_init_trace_data[20]; |
426 | static struct stack_trace lockdep_init_trace = { | |
427 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
428 | .entries = lockdep_init_trace_data, | |
429 | }; | |
fbb9ce95 IM |
430 | |
431 | /* | |
432 | * Various lockdep statistics: | |
433 | */ | |
434 | atomic_t chain_lookup_hits; | |
435 | atomic_t chain_lookup_misses; | |
436 | atomic_t hardirqs_on_events; | |
437 | atomic_t hardirqs_off_events; | |
438 | atomic_t redundant_hardirqs_on; | |
439 | atomic_t redundant_hardirqs_off; | |
440 | atomic_t softirqs_on_events; | |
441 | atomic_t softirqs_off_events; | |
442 | atomic_t redundant_softirqs_on; | |
443 | atomic_t redundant_softirqs_off; | |
444 | atomic_t nr_unused_locks; | |
445 | atomic_t nr_cyclic_checks; | |
fbb9ce95 | 446 | atomic_t nr_find_usage_forwards_checks; |
fbb9ce95 | 447 | atomic_t nr_find_usage_backwards_checks; |
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 | ||
506 | static void print_lock_name(struct lock_class *class) | |
507 | { | |
f510b233 | 508 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
509 | const char *name; |
510 | ||
f510b233 | 511 | get_usage_chars(class, usage); |
fbb9ce95 IM |
512 | |
513 | name = class->name; | |
514 | if (!name) { | |
515 | name = __get_key_name(class->key, str); | |
516 | printk(" (%s", name); | |
517 | } else { | |
518 | printk(" (%s", name); | |
519 | if (class->name_version > 1) | |
520 | printk("#%d", class->name_version); | |
521 | if (class->subclass) | |
522 | printk("/%d", class->subclass); | |
523 | } | |
f510b233 | 524 | printk("){%s}", usage); |
fbb9ce95 IM |
525 | } |
526 | ||
527 | static void print_lockdep_cache(struct lockdep_map *lock) | |
528 | { | |
529 | const char *name; | |
9281acea | 530 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
531 | |
532 | name = lock->name; | |
533 | if (!name) | |
534 | name = __get_key_name(lock->key->subkeys, str); | |
535 | ||
536 | printk("%s", name); | |
537 | } | |
538 | ||
539 | static void print_lock(struct held_lock *hlock) | |
540 | { | |
f82b217e | 541 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
542 | printk(", at: "); |
543 | print_ip_sym(hlock->acquire_ip); | |
544 | } | |
545 | ||
546 | static void lockdep_print_held_locks(struct task_struct *curr) | |
547 | { | |
548 | int i, depth = curr->lockdep_depth; | |
549 | ||
550 | if (!depth) { | |
ba25f9dc | 551 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
552 | return; |
553 | } | |
554 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 555 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
556 | |
557 | for (i = 0; i < depth; i++) { | |
558 | printk(" #%d: ", i); | |
559 | print_lock(curr->held_locks + i); | |
560 | } | |
561 | } | |
fbb9ce95 | 562 | |
8e18257d PZ |
563 | static void print_kernel_version(void) |
564 | { | |
565 | printk("%s %.*s\n", init_utsname()->release, | |
566 | (int)strcspn(init_utsname()->version, " "), | |
567 | init_utsname()->version); | |
568 | } | |
569 | ||
570 | static int very_verbose(struct lock_class *class) | |
571 | { | |
572 | #if VERY_VERBOSE | |
573 | return class_filter(class); | |
574 | #endif | |
575 | return 0; | |
576 | } | |
577 | ||
fbb9ce95 | 578 | /* |
8e18257d | 579 | * Is this the address of a static object: |
fbb9ce95 | 580 | */ |
8e18257d | 581 | static int static_obj(void *obj) |
fbb9ce95 | 582 | { |
8e18257d PZ |
583 | unsigned long start = (unsigned long) &_stext, |
584 | end = (unsigned long) &_end, | |
585 | addr = (unsigned long) obj; | |
586 | #ifdef CONFIG_SMP | |
587 | int i; | |
588 | #endif | |
589 | ||
fbb9ce95 | 590 | /* |
8e18257d | 591 | * static variable? |
fbb9ce95 | 592 | */ |
8e18257d PZ |
593 | if ((addr >= start) && (addr < end)) |
594 | return 1; | |
fbb9ce95 | 595 | |
2a9ad18d MF |
596 | if (arch_is_kernel_data(addr)) |
597 | return 1; | |
598 | ||
8e18257d | 599 | #ifdef CONFIG_SMP |
fbb9ce95 | 600 | /* |
8e18257d | 601 | * percpu var? |
fbb9ce95 | 602 | */ |
8e18257d PZ |
603 | for_each_possible_cpu(i) { |
604 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
605 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
606 | + per_cpu_offset(i); | |
fbb9ce95 | 607 | |
8e18257d PZ |
608 | if ((addr >= start) && (addr < end)) |
609 | return 1; | |
610 | } | |
ca58abcb | 611 | #endif |
fbb9ce95 | 612 | |
8e18257d PZ |
613 | /* |
614 | * module var? | |
615 | */ | |
616 | return is_module_address(addr); | |
99de055a DJ |
617 | } |
618 | ||
fbb9ce95 | 619 | /* |
8e18257d PZ |
620 | * To make lock name printouts unique, we calculate a unique |
621 | * class->name_version generation counter: | |
fbb9ce95 | 622 | */ |
8e18257d | 623 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 624 | { |
8e18257d PZ |
625 | struct lock_class *class; |
626 | int count = 0; | |
fbb9ce95 | 627 | |
8e18257d | 628 | if (!new_class->name) |
fbb9ce95 IM |
629 | return 0; |
630 | ||
8e18257d PZ |
631 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
632 | if (new_class->key - new_class->subclass == class->key) | |
633 | return class->name_version; | |
634 | if (class->name && !strcmp(class->name, new_class->name)) | |
635 | count = max(count, class->name_version); | |
636 | } | |
fbb9ce95 | 637 | |
8e18257d | 638 | return count + 1; |
fbb9ce95 IM |
639 | } |
640 | ||
8e18257d PZ |
641 | /* |
642 | * Register a lock's class in the hash-table, if the class is not present | |
643 | * yet. Otherwise we look it up. We cache the result in the lock object | |
644 | * itself, so actual lookup of the hash should be once per lock object. | |
645 | */ | |
646 | static inline struct lock_class * | |
647 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 648 | { |
8e18257d PZ |
649 | struct lockdep_subclass_key *key; |
650 | struct list_head *hash_head; | |
651 | struct lock_class *class; | |
fbb9ce95 | 652 | |
8e18257d PZ |
653 | #ifdef CONFIG_DEBUG_LOCKDEP |
654 | /* | |
655 | * If the architecture calls into lockdep before initializing | |
656 | * the hashes then we'll warn about it later. (we cannot printk | |
657 | * right now) | |
658 | */ | |
659 | if (unlikely(!lockdep_initialized)) { | |
660 | lockdep_init(); | |
661 | lockdep_init_error = 1; | |
c71063c9 | 662 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
663 | } |
664 | #endif | |
fbb9ce95 | 665 | |
8e18257d PZ |
666 | /* |
667 | * Static locks do not have their class-keys yet - for them the key | |
668 | * is the lock object itself: | |
669 | */ | |
670 | if (unlikely(!lock->key)) | |
671 | lock->key = (void *)lock; | |
fbb9ce95 | 672 | |
8e18257d PZ |
673 | /* |
674 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
675 | * lock_class_key variable is passed in through the mutex_init() | |
676 | * (or spin_lock_init()) call - which acts as the key. For static | |
677 | * locks we use the lock object itself as the key. | |
678 | */ | |
4b32d0a4 PZ |
679 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
680 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 681 | |
8e18257d | 682 | key = lock->key->subkeys + subclass; |
ca268c69 | 683 | |
8e18257d | 684 | hash_head = classhashentry(key); |
74c383f1 | 685 | |
8e18257d PZ |
686 | /* |
687 | * We can walk the hash lockfree, because the hash only | |
688 | * grows, and we are careful when adding entries to the end: | |
689 | */ | |
4b32d0a4 PZ |
690 | list_for_each_entry(class, hash_head, hash_entry) { |
691 | if (class->key == key) { | |
692 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 693 | return class; |
4b32d0a4 PZ |
694 | } |
695 | } | |
fbb9ce95 | 696 | |
8e18257d | 697 | return NULL; |
fbb9ce95 IM |
698 | } |
699 | ||
700 | /* | |
8e18257d PZ |
701 | * Register a lock's class in the hash-table, if the class is not present |
702 | * yet. Otherwise we look it up. We cache the result in the lock object | |
703 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 704 | */ |
8e18257d PZ |
705 | static inline struct lock_class * |
706 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 707 | { |
8e18257d PZ |
708 | struct lockdep_subclass_key *key; |
709 | struct list_head *hash_head; | |
710 | struct lock_class *class; | |
711 | unsigned long flags; | |
712 | ||
713 | class = look_up_lock_class(lock, subclass); | |
714 | if (likely(class)) | |
715 | return class; | |
716 | ||
717 | /* | |
718 | * Debug-check: all keys must be persistent! | |
719 | */ | |
720 | if (!static_obj(lock->key)) { | |
721 | debug_locks_off(); | |
722 | printk("INFO: trying to register non-static key.\n"); | |
723 | printk("the code is fine but needs lockdep annotation.\n"); | |
724 | printk("turning off the locking correctness validator.\n"); | |
725 | dump_stack(); | |
726 | ||
727 | return NULL; | |
728 | } | |
729 | ||
730 | key = lock->key->subkeys + subclass; | |
731 | hash_head = classhashentry(key); | |
732 | ||
733 | raw_local_irq_save(flags); | |
734 | if (!graph_lock()) { | |
735 | raw_local_irq_restore(flags); | |
736 | return NULL; | |
737 | } | |
738 | /* | |
739 | * We have to do the hash-walk again, to avoid races | |
740 | * with another CPU: | |
741 | */ | |
742 | list_for_each_entry(class, hash_head, hash_entry) | |
743 | if (class->key == key) | |
744 | goto out_unlock_set; | |
745 | /* | |
746 | * Allocate a new key from the static array, and add it to | |
747 | * the hash: | |
748 | */ | |
749 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
750 | if (!debug_locks_off_graph_unlock()) { | |
751 | raw_local_irq_restore(flags); | |
752 | return NULL; | |
753 | } | |
754 | raw_local_irq_restore(flags); | |
755 | ||
756 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
757 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 758 | dump_stack(); |
8e18257d PZ |
759 | return NULL; |
760 | } | |
761 | class = lock_classes + nr_lock_classes++; | |
762 | debug_atomic_inc(&nr_unused_locks); | |
763 | class->key = key; | |
764 | class->name = lock->name; | |
765 | class->subclass = subclass; | |
766 | INIT_LIST_HEAD(&class->lock_entry); | |
767 | INIT_LIST_HEAD(&class->locks_before); | |
768 | INIT_LIST_HEAD(&class->locks_after); | |
769 | class->name_version = count_matching_names(class); | |
770 | /* | |
771 | * We use RCU's safe list-add method to make | |
772 | * parallel walking of the hash-list safe: | |
773 | */ | |
774 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
775 | /* |
776 | * Add it to the global list of classes: | |
777 | */ | |
778 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
779 | |
780 | if (verbose(class)) { | |
781 | graph_unlock(); | |
782 | raw_local_irq_restore(flags); | |
783 | ||
784 | printk("\nnew class %p: %s", class->key, class->name); | |
785 | if (class->name_version > 1) | |
786 | printk("#%d", class->name_version); | |
787 | printk("\n"); | |
788 | dump_stack(); | |
789 | ||
790 | raw_local_irq_save(flags); | |
791 | if (!graph_lock()) { | |
792 | raw_local_irq_restore(flags); | |
793 | return NULL; | |
794 | } | |
795 | } | |
796 | out_unlock_set: | |
797 | graph_unlock(); | |
798 | raw_local_irq_restore(flags); | |
799 | ||
800 | if (!subclass || force) | |
801 | lock->class_cache = class; | |
802 | ||
803 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
804 | return NULL; | |
805 | ||
806 | return class; | |
807 | } | |
808 | ||
809 | #ifdef CONFIG_PROVE_LOCKING | |
810 | /* | |
811 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
812 | * with NULL on failure) | |
813 | */ | |
814 | static struct lock_list *alloc_list_entry(void) | |
815 | { | |
816 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
817 | if (!debug_locks_off_graph_unlock()) | |
818 | return NULL; | |
819 | ||
820 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
821 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 822 | dump_stack(); |
8e18257d PZ |
823 | return NULL; |
824 | } | |
825 | return list_entries + nr_list_entries++; | |
826 | } | |
827 | ||
828 | /* | |
829 | * Add a new dependency to the head of the list: | |
830 | */ | |
831 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
832 | struct list_head *head, unsigned long ip, int distance) | |
833 | { | |
834 | struct lock_list *entry; | |
835 | /* | |
836 | * Lock not present yet - get a new dependency struct and | |
837 | * add it to the list: | |
838 | */ | |
839 | entry = alloc_list_entry(); | |
840 | if (!entry) | |
841 | return 0; | |
842 | ||
8e18257d PZ |
843 | if (!save_trace(&entry->trace)) |
844 | return 0; | |
845 | ||
74870172 ZY |
846 | entry->class = this; |
847 | entry->distance = distance; | |
8e18257d PZ |
848 | /* |
849 | * Since we never remove from the dependency list, the list can | |
850 | * be walked lockless by other CPUs, it's only allocation | |
851 | * that must be protected by the spinlock. But this also means | |
852 | * we must make new entries visible only once writes to the | |
853 | * entry become visible - hence the RCU op: | |
854 | */ | |
855 | list_add_tail_rcu(&entry->entry, head); | |
856 | ||
857 | return 1; | |
858 | } | |
859 | ||
98c33edd PZ |
860 | /* |
861 | * For good efficiency of modular, we use power of 2 | |
862 | */ | |
af012961 PZ |
863 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
864 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
865 | ||
98c33edd PZ |
866 | /* |
867 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
868 | * breadth-first search(BFS)algorithem, by which we can build |
869 | * the shortest path from the next lock to be acquired to the | |
870 | * previous held lock if there is a circular between them. | |
98c33edd | 871 | */ |
af012961 PZ |
872 | struct circular_queue { |
873 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
874 | unsigned int front, rear; | |
875 | }; | |
876 | ||
877 | static struct circular_queue lock_cq; | |
af012961 | 878 | |
12f3dfd0 | 879 | unsigned int max_bfs_queue_depth; |
af012961 | 880 | |
e351b660 ML |
881 | static unsigned int lockdep_dependency_gen_id; |
882 | ||
af012961 PZ |
883 | static inline void __cq_init(struct circular_queue *cq) |
884 | { | |
885 | cq->front = cq->rear = 0; | |
e351b660 | 886 | lockdep_dependency_gen_id++; |
af012961 PZ |
887 | } |
888 | ||
889 | static inline int __cq_empty(struct circular_queue *cq) | |
890 | { | |
891 | return (cq->front == cq->rear); | |
892 | } | |
893 | ||
894 | static inline int __cq_full(struct circular_queue *cq) | |
895 | { | |
896 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
897 | } | |
898 | ||
899 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
900 | { | |
901 | if (__cq_full(cq)) | |
902 | return -1; | |
903 | ||
904 | cq->element[cq->rear] = elem; | |
905 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
906 | return 0; | |
907 | } | |
908 | ||
909 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
910 | { | |
911 | if (__cq_empty(cq)) | |
912 | return -1; | |
913 | ||
914 | *elem = cq->element[cq->front]; | |
915 | cq->front = (cq->front + 1) & CQ_MASK; | |
916 | return 0; | |
917 | } | |
918 | ||
919 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
920 | { | |
921 | return (cq->rear - cq->front) & CQ_MASK; | |
922 | } | |
923 | ||
924 | static inline void mark_lock_accessed(struct lock_list *lock, | |
925 | struct lock_list *parent) | |
926 | { | |
927 | unsigned long nr; | |
98c33edd | 928 | |
af012961 PZ |
929 | nr = lock - list_entries; |
930 | WARN_ON(nr >= nr_list_entries); | |
931 | lock->parent = parent; | |
e351b660 | 932 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
933 | } |
934 | ||
935 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
936 | { | |
937 | unsigned long nr; | |
98c33edd | 938 | |
af012961 PZ |
939 | nr = lock - list_entries; |
940 | WARN_ON(nr >= nr_list_entries); | |
e351b660 | 941 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
942 | } |
943 | ||
944 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
945 | { | |
946 | return child->parent; | |
947 | } | |
948 | ||
949 | static inline int get_lock_depth(struct lock_list *child) | |
950 | { | |
951 | int depth = 0; | |
952 | struct lock_list *parent; | |
953 | ||
954 | while ((parent = get_lock_parent(child))) { | |
955 | child = parent; | |
956 | depth++; | |
957 | } | |
958 | return depth; | |
959 | } | |
960 | ||
9e2d551e | 961 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
962 | void *data, |
963 | int (*match)(struct lock_list *entry, void *data), | |
964 | struct lock_list **target_entry, | |
965 | int forward) | |
c94aa5ca ML |
966 | { |
967 | struct lock_list *entry; | |
d588e461 | 968 | struct list_head *head; |
c94aa5ca ML |
969 | struct circular_queue *cq = &lock_cq; |
970 | int ret = 1; | |
971 | ||
9e2d551e | 972 | if (match(source_entry, data)) { |
c94aa5ca ML |
973 | *target_entry = source_entry; |
974 | ret = 0; | |
975 | goto exit; | |
976 | } | |
977 | ||
d588e461 ML |
978 | if (forward) |
979 | head = &source_entry->class->locks_after; | |
980 | else | |
981 | head = &source_entry->class->locks_before; | |
982 | ||
983 | if (list_empty(head)) | |
984 | goto exit; | |
985 | ||
986 | __cq_init(cq); | |
c94aa5ca ML |
987 | __cq_enqueue(cq, (unsigned long)source_entry); |
988 | ||
989 | while (!__cq_empty(cq)) { | |
990 | struct lock_list *lock; | |
c94aa5ca ML |
991 | |
992 | __cq_dequeue(cq, (unsigned long *)&lock); | |
993 | ||
994 | if (!lock->class) { | |
995 | ret = -2; | |
996 | goto exit; | |
997 | } | |
998 | ||
999 | if (forward) | |
1000 | head = &lock->class->locks_after; | |
1001 | else | |
1002 | head = &lock->class->locks_before; | |
1003 | ||
1004 | list_for_each_entry(entry, head, entry) { | |
1005 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 1006 | unsigned int cq_depth; |
c94aa5ca | 1007 | mark_lock_accessed(entry, lock); |
9e2d551e | 1008 | if (match(entry, data)) { |
c94aa5ca ML |
1009 | *target_entry = entry; |
1010 | ret = 0; | |
1011 | goto exit; | |
1012 | } | |
1013 | ||
1014 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1015 | ret = -1; | |
1016 | goto exit; | |
1017 | } | |
12f3dfd0 ML |
1018 | cq_depth = __cq_get_elem_count(cq); |
1019 | if (max_bfs_queue_depth < cq_depth) | |
1020 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1021 | } |
1022 | } | |
1023 | } | |
1024 | exit: | |
1025 | return ret; | |
1026 | } | |
1027 | ||
d7aaba14 | 1028 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1029 | void *data, |
1030 | int (*match)(struct lock_list *entry, void *data), | |
1031 | struct lock_list **target_entry) | |
c94aa5ca | 1032 | { |
9e2d551e | 1033 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1034 | |
1035 | } | |
1036 | ||
d7aaba14 | 1037 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1038 | void *data, |
1039 | int (*match)(struct lock_list *entry, void *data), | |
1040 | struct lock_list **target_entry) | |
c94aa5ca | 1041 | { |
9e2d551e | 1042 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1043 | |
1044 | } | |
1045 | ||
8e18257d PZ |
1046 | /* |
1047 | * Recursive, forwards-direction lock-dependency checking, used for | |
1048 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1049 | * checking. | |
8e18257d | 1050 | */ |
8e18257d PZ |
1051 | |
1052 | /* | |
1053 | * Print a dependency chain entry (this is only done when a deadlock | |
1054 | * has been detected): | |
1055 | */ | |
1056 | static noinline int | |
24208ca7 | 1057 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1058 | { |
1059 | if (debug_locks_silent) | |
1060 | return 0; | |
1061 | printk("\n-> #%u", depth); | |
1062 | print_lock_name(target->class); | |
1063 | printk(":\n"); | |
1064 | print_stack_trace(&target->trace, 6); | |
1065 | ||
1066 | return 0; | |
1067 | } | |
1068 | ||
1069 | /* | |
1070 | * When a circular dependency is detected, print the | |
1071 | * header first: | |
1072 | */ | |
1073 | static noinline int | |
db0002a3 ML |
1074 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1075 | struct held_lock *check_src, | |
1076 | struct held_lock *check_tgt) | |
8e18257d PZ |
1077 | { |
1078 | struct task_struct *curr = current; | |
1079 | ||
c94aa5ca | 1080 | if (debug_locks_silent) |
8e18257d PZ |
1081 | return 0; |
1082 | ||
1083 | printk("\n=======================================================\n"); | |
1084 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1085 | print_kernel_version(); | |
1086 | printk( "-------------------------------------------------------\n"); | |
1087 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1088 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1089 | print_lock(check_src); |
8e18257d | 1090 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1091 | print_lock(check_tgt); |
8e18257d PZ |
1092 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1093 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1094 | ||
1095 | print_circular_bug_entry(entry, depth); | |
1096 | ||
1097 | return 0; | |
1098 | } | |
1099 | ||
9e2d551e ML |
1100 | static inline int class_equal(struct lock_list *entry, void *data) |
1101 | { | |
1102 | return entry->class == data; | |
1103 | } | |
1104 | ||
db0002a3 ML |
1105 | static noinline int print_circular_bug(struct lock_list *this, |
1106 | struct lock_list *target, | |
1107 | struct held_lock *check_src, | |
1108 | struct held_lock *check_tgt) | |
8e18257d PZ |
1109 | { |
1110 | struct task_struct *curr = current; | |
c94aa5ca | 1111 | struct lock_list *parent; |
24208ca7 | 1112 | int depth; |
8e18257d | 1113 | |
c94aa5ca | 1114 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1115 | return 0; |
1116 | ||
db0002a3 | 1117 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1118 | return 0; |
1119 | ||
c94aa5ca ML |
1120 | depth = get_lock_depth(target); |
1121 | ||
db0002a3 | 1122 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1123 | |
1124 | parent = get_lock_parent(target); | |
1125 | ||
1126 | while (parent) { | |
1127 | print_circular_bug_entry(parent, --depth); | |
1128 | parent = get_lock_parent(parent); | |
1129 | } | |
8e18257d PZ |
1130 | |
1131 | printk("\nother info that might help us debug this:\n\n"); | |
1132 | lockdep_print_held_locks(curr); | |
1133 | ||
1134 | printk("\nstack backtrace:\n"); | |
1135 | dump_stack(); | |
1136 | ||
1137 | return 0; | |
1138 | } | |
1139 | ||
db0002a3 ML |
1140 | static noinline int print_bfs_bug(int ret) |
1141 | { | |
1142 | if (!debug_locks_off_graph_unlock()) | |
1143 | return 0; | |
1144 | ||
1145 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1146 | ||
1147 | return 0; | |
1148 | } | |
1149 | ||
ef681026 | 1150 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1151 | { |
ef681026 ML |
1152 | (*(unsigned long *)data)++; |
1153 | return 0; | |
1154 | } | |
419ca3f1 | 1155 | |
ef681026 ML |
1156 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1157 | { | |
1158 | unsigned long count = 0; | |
1159 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1160 | |
ef681026 | 1161 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1162 | |
ef681026 | 1163 | return count; |
419ca3f1 | 1164 | } |
419ca3f1 DM |
1165 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1166 | { | |
1167 | unsigned long ret, flags; | |
ef681026 ML |
1168 | struct lock_list this; |
1169 | ||
1170 | this.parent = NULL; | |
1171 | this.class = class; | |
419ca3f1 DM |
1172 | |
1173 | local_irq_save(flags); | |
0199c4e6 | 1174 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1175 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1176 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1177 | local_irq_restore(flags); |
1178 | ||
1179 | return ret; | |
1180 | } | |
1181 | ||
ef681026 | 1182 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1183 | { |
ef681026 ML |
1184 | unsigned long count = 0; |
1185 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1186 | |
ef681026 | 1187 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1188 | |
ef681026 | 1189 | return count; |
419ca3f1 DM |
1190 | } |
1191 | ||
1192 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1193 | { | |
1194 | unsigned long ret, flags; | |
ef681026 ML |
1195 | struct lock_list this; |
1196 | ||
1197 | this.parent = NULL; | |
1198 | this.class = class; | |
419ca3f1 DM |
1199 | |
1200 | local_irq_save(flags); | |
0199c4e6 | 1201 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1202 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1203 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1204 | local_irq_restore(flags); |
1205 | ||
1206 | return ret; | |
1207 | } | |
1208 | ||
8e18257d PZ |
1209 | /* |
1210 | * Prove that the dependency graph starting at <entry> can not | |
1211 | * lead to <target>. Print an error and return 0 if it does. | |
1212 | */ | |
1213 | static noinline int | |
db0002a3 ML |
1214 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1215 | struct lock_list **target_entry) | |
8e18257d | 1216 | { |
db0002a3 | 1217 | int result; |
8e18257d | 1218 | |
db0002a3 | 1219 | debug_atomic_inc(&nr_cyclic_checks); |
419ca3f1 | 1220 | |
d7aaba14 | 1221 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1222 | |
db0002a3 ML |
1223 | return result; |
1224 | } | |
c94aa5ca | 1225 | |
81d68a96 | 1226 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1227 | /* |
1228 | * Forwards and backwards subgraph searching, for the purposes of | |
1229 | * proving that two subgraphs can be connected by a new dependency | |
1230 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1231 | */ | |
fbb9ce95 | 1232 | |
d7aaba14 ML |
1233 | static inline int usage_match(struct lock_list *entry, void *bit) |
1234 | { | |
1235 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1236 | } | |
1237 | ||
1238 | ||
1239 | ||
fbb9ce95 IM |
1240 | /* |
1241 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1242 | * at @root->class that matches @bit. |
fbb9ce95 | 1243 | * |
d7aaba14 ML |
1244 | * Return 0 if such a node exists in the subgraph, and put that node |
1245 | * into *@target_entry. | |
fbb9ce95 | 1246 | * |
d7aaba14 ML |
1247 | * Return 1 otherwise and keep *@target_entry unchanged. |
1248 | * Return <0 on error. | |
fbb9ce95 | 1249 | */ |
d7aaba14 ML |
1250 | static int |
1251 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1252 | struct lock_list **target_entry) | |
fbb9ce95 | 1253 | { |
d7aaba14 | 1254 | int result; |
fbb9ce95 IM |
1255 | |
1256 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
fbb9ce95 | 1257 | |
d7aaba14 ML |
1258 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1259 | ||
1260 | return result; | |
fbb9ce95 IM |
1261 | } |
1262 | ||
1263 | /* | |
1264 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1265 | * at @root->class that matches @bit. |
fbb9ce95 | 1266 | * |
d7aaba14 ML |
1267 | * Return 0 if such a node exists in the subgraph, and put that node |
1268 | * into *@target_entry. | |
fbb9ce95 | 1269 | * |
d7aaba14 ML |
1270 | * Return 1 otherwise and keep *@target_entry unchanged. |
1271 | * Return <0 on error. | |
fbb9ce95 | 1272 | */ |
d7aaba14 ML |
1273 | static int |
1274 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1275 | struct lock_list **target_entry) | |
fbb9ce95 | 1276 | { |
d7aaba14 | 1277 | int result; |
fbb9ce95 IM |
1278 | |
1279 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
fbb9ce95 | 1280 | |
d7aaba14 | 1281 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1282 | |
d7aaba14 | 1283 | return result; |
fbb9ce95 IM |
1284 | } |
1285 | ||
af012961 PZ |
1286 | static void print_lock_class_header(struct lock_class *class, int depth) |
1287 | { | |
1288 | int bit; | |
1289 | ||
1290 | printk("%*s->", depth, ""); | |
1291 | print_lock_name(class); | |
1292 | printk(" ops: %lu", class->ops); | |
1293 | printk(" {\n"); | |
1294 | ||
1295 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1296 | if (class->usage_mask & (1 << bit)) { | |
1297 | int len = depth; | |
1298 | ||
1299 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1300 | len += printk(" at:\n"); | |
1301 | print_stack_trace(class->usage_traces + bit, len); | |
1302 | } | |
1303 | } | |
1304 | printk("%*s }\n", depth, ""); | |
1305 | ||
1306 | printk("%*s ... key at: ",depth,""); | |
1307 | print_ip_sym((unsigned long)class->key); | |
1308 | } | |
1309 | ||
1310 | /* | |
1311 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1312 | */ | |
1313 | static void __used | |
1314 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1315 | struct lock_list *root) | |
1316 | { | |
1317 | struct lock_list *entry = leaf; | |
1318 | int depth; | |
1319 | ||
1320 | /*compute depth from generated tree by BFS*/ | |
1321 | depth = get_lock_depth(leaf); | |
1322 | ||
1323 | do { | |
1324 | print_lock_class_header(entry->class, depth); | |
1325 | printk("%*s ... acquired at:\n", depth, ""); | |
1326 | print_stack_trace(&entry->trace, 2); | |
1327 | printk("\n"); | |
1328 | ||
1329 | if (depth == 0 && (entry != root)) { | |
1330 | printk("lockdep:%s bad BFS generated tree\n", __func__); | |
1331 | break; | |
1332 | } | |
1333 | ||
1334 | entry = get_lock_parent(entry); | |
1335 | depth--; | |
1336 | } while (entry && (depth >= 0)); | |
1337 | ||
1338 | return; | |
1339 | } | |
d7aaba14 | 1340 | |
fbb9ce95 IM |
1341 | static int |
1342 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1343 | struct lock_list *prev_root, |
1344 | struct lock_list *next_root, | |
1345 | struct lock_list *backwards_entry, | |
1346 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1347 | struct held_lock *prev, |
1348 | struct held_lock *next, | |
1349 | enum lock_usage_bit bit1, | |
1350 | enum lock_usage_bit bit2, | |
1351 | const char *irqclass) | |
1352 | { | |
74c383f1 | 1353 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1354 | return 0; |
1355 | ||
1356 | printk("\n======================================================\n"); | |
1357 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1358 | irqclass, irqclass); | |
99de055a | 1359 | print_kernel_version(); |
fbb9ce95 IM |
1360 | printk( "------------------------------------------------------\n"); |
1361 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1362 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1363 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1364 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1365 | curr->hardirqs_enabled, | |
1366 | curr->softirqs_enabled); | |
1367 | print_lock(next); | |
1368 | ||
1369 | printk("\nand this task is already holding:\n"); | |
1370 | print_lock(prev); | |
1371 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1372 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1373 | printk(" ->"); |
f82b217e | 1374 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1375 | printk("\n"); |
1376 | ||
1377 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1378 | irqclass); | |
24208ca7 | 1379 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1380 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1381 | ||
24208ca7 | 1382 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1383 | |
1384 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1385 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1386 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1387 | printk("..."); | |
1388 | ||
24208ca7 | 1389 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1390 | |
1391 | printk("\nother info that might help us debug this:\n\n"); | |
1392 | lockdep_print_held_locks(curr); | |
1393 | ||
24208ca7 ML |
1394 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1395 | printk(" and the holding lock:\n"); | |
1396 | if (!save_trace(&prev_root->trace)) | |
1397 | return 0; | |
1398 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1399 | |
24208ca7 ML |
1400 | printk("\nthe dependencies between the lock to be acquired"); |
1401 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1402 | if (!save_trace(&next_root->trace)) | |
1403 | return 0; | |
1404 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1405 | |
1406 | printk("\nstack backtrace:\n"); | |
1407 | dump_stack(); | |
1408 | ||
1409 | return 0; | |
1410 | } | |
1411 | ||
1412 | static int | |
1413 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1414 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1415 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1416 | { | |
1417 | int ret; | |
24208ca7 | 1418 | struct lock_list this, that; |
d7aaba14 | 1419 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1420 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1421 | |
1422 | this.parent = NULL; | |
1423 | ||
1424 | this.class = hlock_class(prev); | |
1425 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1426 | if (ret < 0) |
1427 | return print_bfs_bug(ret); | |
1428 | if (ret == 1) | |
1429 | return ret; | |
d7aaba14 | 1430 | |
24208ca7 ML |
1431 | that.parent = NULL; |
1432 | that.class = hlock_class(next); | |
1433 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1434 | if (ret < 0) |
1435 | return print_bfs_bug(ret); | |
1436 | if (ret == 1) | |
1437 | return ret; | |
fbb9ce95 | 1438 | |
24208ca7 ML |
1439 | return print_bad_irq_dependency(curr, &this, &that, |
1440 | target_entry, target_entry1, | |
1441 | prev, next, | |
fbb9ce95 IM |
1442 | bit_backwards, bit_forwards, irqclass); |
1443 | } | |
1444 | ||
4f367d8a PZ |
1445 | static const char *state_names[] = { |
1446 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1447 | __stringify(__STATE), |
4f367d8a PZ |
1448 | #include "lockdep_states.h" |
1449 | #undef LOCKDEP_STATE | |
1450 | }; | |
1451 | ||
1452 | static const char *state_rnames[] = { | |
1453 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1454 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1455 | #include "lockdep_states.h" |
1456 | #undef LOCKDEP_STATE | |
1457 | }; | |
1458 | ||
1459 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1460 | { |
4f367d8a PZ |
1461 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1462 | } | |
8e18257d | 1463 | |
4f367d8a PZ |
1464 | static int exclusive_bit(int new_bit) |
1465 | { | |
8e18257d | 1466 | /* |
4f367d8a PZ |
1467 | * USED_IN |
1468 | * USED_IN_READ | |
1469 | * ENABLED | |
1470 | * ENABLED_READ | |
1471 | * | |
1472 | * bit 0 - write/read | |
1473 | * bit 1 - used_in/enabled | |
1474 | * bit 2+ state | |
8e18257d | 1475 | */ |
4f367d8a PZ |
1476 | |
1477 | int state = new_bit & ~3; | |
1478 | int dir = new_bit & 2; | |
8e18257d PZ |
1479 | |
1480 | /* | |
4f367d8a | 1481 | * keep state, bit flip the direction and strip read. |
8e18257d | 1482 | */ |
4f367d8a PZ |
1483 | return state | (dir ^ 2); |
1484 | } | |
1485 | ||
1486 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1487 | struct held_lock *next, enum lock_usage_bit bit) | |
1488 | { | |
8e18257d | 1489 | /* |
4f367d8a PZ |
1490 | * Prove that the new dependency does not connect a hardirq-safe |
1491 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1492 | * the backwards-subgraph starting at <prev>, and the |
1493 | * forwards-subgraph starting at <next>: | |
1494 | */ | |
4f367d8a PZ |
1495 | if (!check_usage(curr, prev, next, bit, |
1496 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1497 | return 0; |
1498 | ||
4f367d8a PZ |
1499 | bit++; /* _READ */ |
1500 | ||
cf40bd16 | 1501 | /* |
4f367d8a PZ |
1502 | * Prove that the new dependency does not connect a hardirq-safe-read |
1503 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1504 | * the backwards-subgraph starting at <prev>, and the |
1505 | * forwards-subgraph starting at <next>: | |
1506 | */ | |
4f367d8a PZ |
1507 | if (!check_usage(curr, prev, next, bit, |
1508 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1509 | return 0; |
1510 | ||
4f367d8a PZ |
1511 | return 1; |
1512 | } | |
1513 | ||
1514 | static int | |
1515 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1516 | struct held_lock *next) | |
1517 | { | |
1518 | #define LOCKDEP_STATE(__STATE) \ | |
1519 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1520 | return 0; |
4f367d8a PZ |
1521 | #include "lockdep_states.h" |
1522 | #undef LOCKDEP_STATE | |
cf40bd16 | 1523 | |
8e18257d PZ |
1524 | return 1; |
1525 | } | |
1526 | ||
1527 | static void inc_chains(void) | |
1528 | { | |
1529 | if (current->hardirq_context) | |
1530 | nr_hardirq_chains++; | |
1531 | else { | |
1532 | if (current->softirq_context) | |
1533 | nr_softirq_chains++; | |
1534 | else | |
1535 | nr_process_chains++; | |
1536 | } | |
1537 | } | |
1538 | ||
1539 | #else | |
1540 | ||
1541 | static inline int | |
1542 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1543 | struct held_lock *next) | |
1544 | { | |
1545 | return 1; | |
1546 | } | |
1547 | ||
1548 | static inline void inc_chains(void) | |
1549 | { | |
1550 | nr_process_chains++; | |
1551 | } | |
1552 | ||
fbb9ce95 IM |
1553 | #endif |
1554 | ||
1555 | static int | |
1556 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1557 | struct held_lock *next) | |
1558 | { | |
74c383f1 | 1559 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1560 | return 0; |
1561 | ||
1562 | printk("\n=============================================\n"); | |
1563 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1564 | print_kernel_version(); |
fbb9ce95 IM |
1565 | printk( "---------------------------------------------\n"); |
1566 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1567 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1568 | print_lock(next); |
1569 | printk("\nbut task is already holding lock:\n"); | |
1570 | print_lock(prev); | |
1571 | ||
1572 | printk("\nother info that might help us debug this:\n"); | |
1573 | lockdep_print_held_locks(curr); | |
1574 | ||
1575 | printk("\nstack backtrace:\n"); | |
1576 | dump_stack(); | |
1577 | ||
1578 | return 0; | |
1579 | } | |
1580 | ||
1581 | /* | |
1582 | * Check whether we are holding such a class already. | |
1583 | * | |
1584 | * (Note that this has to be done separately, because the graph cannot | |
1585 | * detect such classes of deadlocks.) | |
1586 | * | |
1587 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1588 | */ | |
1589 | static int | |
1590 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1591 | struct lockdep_map *next_instance, int read) | |
1592 | { | |
1593 | struct held_lock *prev; | |
7531e2f3 | 1594 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1595 | int i; |
1596 | ||
1597 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1598 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1599 | |
1600 | if (prev->instance == next->nest_lock) | |
1601 | nest = prev; | |
1602 | ||
f82b217e | 1603 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1604 | continue; |
7531e2f3 | 1605 | |
fbb9ce95 IM |
1606 | /* |
1607 | * Allow read-after-read recursion of the same | |
6c9076ec | 1608 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1609 | */ |
6c9076ec | 1610 | if ((read == 2) && prev->read) |
fbb9ce95 | 1611 | return 2; |
7531e2f3 PZ |
1612 | |
1613 | /* | |
1614 | * We're holding the nest_lock, which serializes this lock's | |
1615 | * nesting behaviour. | |
1616 | */ | |
1617 | if (nest) | |
1618 | return 2; | |
1619 | ||
fbb9ce95 IM |
1620 | return print_deadlock_bug(curr, prev, next); |
1621 | } | |
1622 | return 1; | |
1623 | } | |
1624 | ||
1625 | /* | |
1626 | * There was a chain-cache miss, and we are about to add a new dependency | |
1627 | * to a previous lock. We recursively validate the following rules: | |
1628 | * | |
1629 | * - would the adding of the <prev> -> <next> dependency create a | |
1630 | * circular dependency in the graph? [== circular deadlock] | |
1631 | * | |
1632 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1633 | * (in the full backwards-subgraph starting at <prev>) with any | |
1634 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1635 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1636 | * | |
1637 | * - does the new prev->next dependency connect any softirq-safe lock | |
1638 | * (in the full backwards-subgraph starting at <prev>) with any | |
1639 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1640 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1641 | * | |
1642 | * any of these scenarios could lead to a deadlock. | |
1643 | * | |
1644 | * Then if all the validations pass, we add the forwards and backwards | |
1645 | * dependency. | |
1646 | */ | |
1647 | static int | |
1648 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1649 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1650 | { |
1651 | struct lock_list *entry; | |
1652 | int ret; | |
db0002a3 ML |
1653 | struct lock_list this; |
1654 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 IM |
1655 | |
1656 | /* | |
1657 | * Prove that the new <prev> -> <next> dependency would not | |
1658 | * create a circular dependency in the graph. (We do this by | |
1659 | * forward-recursing into the graph starting at <next>, and | |
1660 | * checking whether we can reach <prev>.) | |
1661 | * | |
1662 | * We are using global variables to control the recursion, to | |
1663 | * keep the stackframe size of the recursive functions low: | |
1664 | */ | |
db0002a3 ML |
1665 | this.class = hlock_class(next); |
1666 | this.parent = NULL; | |
1667 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1668 | if (unlikely(!ret)) | |
1669 | return print_circular_bug(&this, target_entry, next, prev); | |
1670 | else if (unlikely(ret < 0)) | |
1671 | return print_bfs_bug(ret); | |
c94aa5ca | 1672 | |
8e18257d | 1673 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1674 | return 0; |
1675 | ||
fbb9ce95 IM |
1676 | /* |
1677 | * For recursive read-locks we do all the dependency checks, | |
1678 | * but we dont store read-triggered dependencies (only | |
1679 | * write-triggered dependencies). This ensures that only the | |
1680 | * write-side dependencies matter, and that if for example a | |
1681 | * write-lock never takes any other locks, then the reads are | |
1682 | * equivalent to a NOP. | |
1683 | */ | |
1684 | if (next->read == 2 || prev->read == 2) | |
1685 | return 1; | |
1686 | /* | |
1687 | * Is the <prev> -> <next> dependency already present? | |
1688 | * | |
1689 | * (this may occur even though this is a new chain: consider | |
1690 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1691 | * chains - the second one will be new, but L1 already has | |
1692 | * L2 added to its dependency list, due to the first chain.) | |
1693 | */ | |
f82b217e DJ |
1694 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1695 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1696 | if (distance == 1) |
1697 | entry->distance = 1; | |
fbb9ce95 | 1698 | return 2; |
068135e6 | 1699 | } |
fbb9ce95 IM |
1700 | } |
1701 | ||
1702 | /* | |
1703 | * Ok, all validations passed, add the new lock | |
1704 | * to the previous lock's dependency list: | |
1705 | */ | |
f82b217e DJ |
1706 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1707 | &hlock_class(prev)->locks_after, | |
1708 | next->acquire_ip, distance); | |
068135e6 | 1709 | |
fbb9ce95 IM |
1710 | if (!ret) |
1711 | return 0; | |
910b1b2e | 1712 | |
f82b217e DJ |
1713 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1714 | &hlock_class(next)->locks_before, | |
1715 | next->acquire_ip, distance); | |
910b1b2e JP |
1716 | if (!ret) |
1717 | return 0; | |
fbb9ce95 IM |
1718 | |
1719 | /* | |
8e18257d PZ |
1720 | * Debugging printouts: |
1721 | */ | |
f82b217e | 1722 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1723 | graph_unlock(); |
1724 | printk("\n new dependency: "); | |
f82b217e | 1725 | print_lock_name(hlock_class(prev)); |
8e18257d | 1726 | printk(" => "); |
f82b217e | 1727 | print_lock_name(hlock_class(next)); |
8e18257d | 1728 | printk("\n"); |
fbb9ce95 | 1729 | dump_stack(); |
8e18257d | 1730 | return graph_lock(); |
fbb9ce95 | 1731 | } |
8e18257d PZ |
1732 | return 1; |
1733 | } | |
fbb9ce95 | 1734 | |
8e18257d PZ |
1735 | /* |
1736 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1737 | * The ones that are relevant are (in increasing distance from curr): | |
1738 | * all consecutive trylock entries and the final non-trylock entry - or | |
1739 | * the end of this context's lock-chain - whichever comes first. | |
1740 | */ | |
1741 | static int | |
1742 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1743 | { | |
1744 | int depth = curr->lockdep_depth; | |
1745 | struct held_lock *hlock; | |
d6d897ce | 1746 | |
fbb9ce95 | 1747 | /* |
8e18257d PZ |
1748 | * Debugging checks. |
1749 | * | |
1750 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1751 | */ |
8e18257d PZ |
1752 | if (!depth) |
1753 | goto out_bug; | |
fbb9ce95 | 1754 | /* |
8e18257d PZ |
1755 | * At least two relevant locks must exist for this |
1756 | * to be a head: | |
fbb9ce95 | 1757 | */ |
8e18257d PZ |
1758 | if (curr->held_locks[depth].irq_context != |
1759 | curr->held_locks[depth-1].irq_context) | |
1760 | goto out_bug; | |
74c383f1 | 1761 | |
8e18257d PZ |
1762 | for (;;) { |
1763 | int distance = curr->lockdep_depth - depth + 1; | |
1764 | hlock = curr->held_locks + depth-1; | |
1765 | /* | |
1766 | * Only non-recursive-read entries get new dependencies | |
1767 | * added: | |
1768 | */ | |
1769 | if (hlock->read != 2) { | |
1770 | if (!check_prev_add(curr, hlock, next, distance)) | |
1771 | return 0; | |
1772 | /* | |
1773 | * Stop after the first non-trylock entry, | |
1774 | * as non-trylock entries have added their | |
1775 | * own direct dependencies already, so this | |
1776 | * lock is connected to them indirectly: | |
1777 | */ | |
1778 | if (!hlock->trylock) | |
1779 | break; | |
74c383f1 | 1780 | } |
8e18257d PZ |
1781 | depth--; |
1782 | /* | |
1783 | * End of lock-stack? | |
1784 | */ | |
1785 | if (!depth) | |
1786 | break; | |
1787 | /* | |
1788 | * Stop the search if we cross into another context: | |
1789 | */ | |
1790 | if (curr->held_locks[depth].irq_context != | |
1791 | curr->held_locks[depth-1].irq_context) | |
1792 | break; | |
fbb9ce95 | 1793 | } |
8e18257d PZ |
1794 | return 1; |
1795 | out_bug: | |
1796 | if (!debug_locks_off_graph_unlock()) | |
1797 | return 0; | |
fbb9ce95 | 1798 | |
8e18257d | 1799 | WARN_ON(1); |
fbb9ce95 | 1800 | |
8e18257d | 1801 | return 0; |
fbb9ce95 IM |
1802 | } |
1803 | ||
8e18257d | 1804 | unsigned long nr_lock_chains; |
443cd507 | 1805 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1806 | int nr_chain_hlocks; |
443cd507 HY |
1807 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1808 | ||
1809 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1810 | { | |
1811 | return lock_classes + chain_hlocks[chain->base + i]; | |
1812 | } | |
8e18257d | 1813 | |
fbb9ce95 IM |
1814 | /* |
1815 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1816 | * add it and return 1 - in this case the new dependency chain is |
1817 | * validated. If the key is already hashed, return 0. | |
1818 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1819 | */ |
443cd507 HY |
1820 | static inline int lookup_chain_cache(struct task_struct *curr, |
1821 | struct held_lock *hlock, | |
1822 | u64 chain_key) | |
fbb9ce95 | 1823 | { |
f82b217e | 1824 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1825 | struct list_head *hash_head = chainhashentry(chain_key); |
1826 | struct lock_chain *chain; | |
443cd507 | 1827 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1828 | int i, j, n, cn; |
fbb9ce95 | 1829 | |
381a2292 JP |
1830 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1831 | return 0; | |
fbb9ce95 IM |
1832 | /* |
1833 | * We can walk it lock-free, because entries only get added | |
1834 | * to the hash: | |
1835 | */ | |
1836 | list_for_each_entry(chain, hash_head, entry) { | |
1837 | if (chain->chain_key == chain_key) { | |
1838 | cache_hit: | |
1839 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1840 | if (very_verbose(class)) |
755cd900 AM |
1841 | printk("\nhash chain already cached, key: " |
1842 | "%016Lx tail class: [%p] %s\n", | |
1843 | (unsigned long long)chain_key, | |
1844 | class->key, class->name); | |
fbb9ce95 IM |
1845 | return 0; |
1846 | } | |
1847 | } | |
81fc685a | 1848 | if (very_verbose(class)) |
755cd900 AM |
1849 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1850 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1851 | /* |
1852 | * Allocate a new chain entry from the static array, and add | |
1853 | * it to the hash: | |
1854 | */ | |
74c383f1 IM |
1855 | if (!graph_lock()) |
1856 | return 0; | |
fbb9ce95 IM |
1857 | /* |
1858 | * We have to walk the chain again locked - to avoid duplicates: | |
1859 | */ | |
1860 | list_for_each_entry(chain, hash_head, entry) { | |
1861 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1862 | graph_unlock(); |
fbb9ce95 IM |
1863 | goto cache_hit; |
1864 | } | |
1865 | } | |
1866 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1867 | if (!debug_locks_off_graph_unlock()) |
1868 | return 0; | |
1869 | ||
fbb9ce95 IM |
1870 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1871 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 1872 | dump_stack(); |
fbb9ce95 IM |
1873 | return 0; |
1874 | } | |
1875 | chain = lock_chains + nr_lock_chains++; | |
1876 | chain->chain_key = chain_key; | |
443cd507 HY |
1877 | chain->irq_context = hlock->irq_context; |
1878 | /* Find the first held_lock of current chain */ | |
1879 | hlock_next = hlock; | |
1880 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1881 | hlock_curr = curr->held_locks + i; | |
1882 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1883 | break; | |
1884 | hlock_next = hlock; | |
1885 | } | |
1886 | i++; | |
1887 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1888 | cn = nr_chain_hlocks; |
1889 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1890 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1891 | if (n == cn) | |
1892 | break; | |
1893 | cn = n; | |
1894 | } | |
1895 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1896 | chain->base = cn; | |
443cd507 | 1897 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1898 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1899 | chain_hlocks[chain->base + j] = lock_id; |
1900 | } | |
1901 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1902 | } | |
fbb9ce95 IM |
1903 | list_add_tail_rcu(&chain->entry, hash_head); |
1904 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1905 | inc_chains(); |
1906 | ||
1907 | return 1; | |
1908 | } | |
1909 | ||
1910 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1911 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1912 | { |
1913 | /* | |
1914 | * Trylock needs to maintain the stack of held locks, but it | |
1915 | * does not add new dependencies, because trylock can be done | |
1916 | * in any order. | |
1917 | * | |
1918 | * We look up the chain_key and do the O(N^2) check and update of | |
1919 | * the dependencies only if this is a new dependency chain. | |
1920 | * (If lookup_chain_cache() returns with 1 it acquires | |
1921 | * graph_lock for us) | |
1922 | */ | |
1923 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1924 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1925 | /* |
1926 | * Check whether last held lock: | |
1927 | * | |
1928 | * - is irq-safe, if this lock is irq-unsafe | |
1929 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1930 | * | |
1931 | * And check whether the new lock's dependency graph | |
1932 | * could lead back to the previous lock. | |
1933 | * | |
1934 | * any of these scenarios could lead to a deadlock. If | |
1935 | * All validations | |
1936 | */ | |
1937 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1938 | ||
1939 | if (!ret) | |
1940 | return 0; | |
1941 | /* | |
1942 | * Mark recursive read, as we jump over it when | |
1943 | * building dependencies (just like we jump over | |
1944 | * trylock entries): | |
1945 | */ | |
1946 | if (ret == 2) | |
1947 | hlock->read = 2; | |
1948 | /* | |
1949 | * Add dependency only if this lock is not the head | |
1950 | * of the chain, and if it's not a secondary read-lock: | |
1951 | */ | |
1952 | if (!chain_head && ret != 2) | |
1953 | if (!check_prevs_add(curr, hlock)) | |
1954 | return 0; | |
1955 | graph_unlock(); | |
1956 | } else | |
1957 | /* after lookup_chain_cache(): */ | |
1958 | if (unlikely(!debug_locks)) | |
1959 | return 0; | |
fbb9ce95 IM |
1960 | |
1961 | return 1; | |
1962 | } | |
8e18257d PZ |
1963 | #else |
1964 | static inline int validate_chain(struct task_struct *curr, | |
1965 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1966 | int chain_head, u64 chain_key) |
8e18257d PZ |
1967 | { |
1968 | return 1; | |
1969 | } | |
ca58abcb | 1970 | #endif |
fbb9ce95 IM |
1971 | |
1972 | /* | |
1973 | * We are building curr_chain_key incrementally, so double-check | |
1974 | * it from scratch, to make sure that it's done correctly: | |
1975 | */ | |
1d09daa5 | 1976 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1977 | { |
1978 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1979 | struct held_lock *hlock, *prev_hlock = NULL; | |
1980 | unsigned int i, id; | |
1981 | u64 chain_key = 0; | |
1982 | ||
1983 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1984 | hlock = curr->held_locks + i; | |
1985 | if (chain_key != hlock->prev_chain_key) { | |
1986 | debug_locks_off(); | |
2df8b1d6 | 1987 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1988 | curr->lockdep_depth, i, |
1989 | (unsigned long long)chain_key, | |
1990 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1991 | return; |
1992 | } | |
f82b217e | 1993 | id = hlock->class_idx - 1; |
381a2292 JP |
1994 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1995 | return; | |
1996 | ||
fbb9ce95 IM |
1997 | if (prev_hlock && (prev_hlock->irq_context != |
1998 | hlock->irq_context)) | |
1999 | chain_key = 0; | |
2000 | chain_key = iterate_chain_key(chain_key, id); | |
2001 | prev_hlock = hlock; | |
2002 | } | |
2003 | if (chain_key != curr->curr_chain_key) { | |
2004 | debug_locks_off(); | |
2df8b1d6 | 2005 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2006 | curr->lockdep_depth, i, |
2007 | (unsigned long long)chain_key, | |
2008 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2009 | } |
2010 | #endif | |
2011 | } | |
2012 | ||
8e18257d PZ |
2013 | static int |
2014 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2015 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2016 | { | |
2017 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2018 | return 0; | |
2019 | ||
2020 | printk("\n=================================\n"); | |
2021 | printk( "[ INFO: inconsistent lock state ]\n"); | |
2022 | print_kernel_version(); | |
2023 | printk( "---------------------------------\n"); | |
2024 | ||
2025 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2026 | usage_str[prev_bit], usage_str[new_bit]); | |
2027 | ||
2028 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2029 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2030 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2031 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2032 | trace_hardirqs_enabled(curr), | |
2033 | trace_softirqs_enabled(curr)); | |
2034 | print_lock(this); | |
2035 | ||
2036 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2037 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2038 | |
2039 | print_irqtrace_events(curr); | |
2040 | printk("\nother info that might help us debug this:\n"); | |
2041 | lockdep_print_held_locks(curr); | |
2042 | ||
2043 | printk("\nstack backtrace:\n"); | |
2044 | dump_stack(); | |
2045 | ||
2046 | return 0; | |
2047 | } | |
2048 | ||
2049 | /* | |
2050 | * Print out an error if an invalid bit is set: | |
2051 | */ | |
2052 | static inline int | |
2053 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2054 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2055 | { | |
f82b217e | 2056 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2057 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2058 | return 1; | |
2059 | } | |
2060 | ||
2061 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2062 | enum lock_usage_bit new_bit); | |
2063 | ||
81d68a96 | 2064 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2065 | |
2066 | /* | |
2067 | * print irq inversion bug: | |
2068 | */ | |
2069 | static int | |
24208ca7 ML |
2070 | print_irq_inversion_bug(struct task_struct *curr, |
2071 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2072 | struct held_lock *this, int forwards, |
2073 | const char *irqclass) | |
2074 | { | |
74c383f1 | 2075 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2076 | return 0; |
2077 | ||
2078 | printk("\n=========================================================\n"); | |
2079 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2080 | print_kernel_version(); |
fbb9ce95 IM |
2081 | printk( "---------------------------------------------------------\n"); |
2082 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2083 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2084 | print_lock(this); |
2085 | if (forwards) | |
26575e28 | 2086 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2087 | else |
26575e28 | 2088 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2089 | print_lock_name(other->class); |
fbb9ce95 IM |
2090 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2091 | ||
2092 | printk("\nother info that might help us debug this:\n"); | |
2093 | lockdep_print_held_locks(curr); | |
2094 | ||
24208ca7 ML |
2095 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2096 | if (!save_trace(&root->trace)) | |
2097 | return 0; | |
2098 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2099 | |
2100 | printk("\nstack backtrace:\n"); | |
2101 | dump_stack(); | |
2102 | ||
2103 | return 0; | |
2104 | } | |
2105 | ||
2106 | /* | |
2107 | * Prove that in the forwards-direction subgraph starting at <this> | |
2108 | * there is no lock matching <mask>: | |
2109 | */ | |
2110 | static int | |
2111 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2112 | enum lock_usage_bit bit, const char *irqclass) | |
2113 | { | |
2114 | int ret; | |
d7aaba14 ML |
2115 | struct lock_list root; |
2116 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2117 | |
d7aaba14 ML |
2118 | root.parent = NULL; |
2119 | root.class = hlock_class(this); | |
2120 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2121 | if (ret < 0) |
2122 | return print_bfs_bug(ret); | |
2123 | if (ret == 1) | |
2124 | return ret; | |
fbb9ce95 | 2125 | |
24208ca7 | 2126 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2127 | this, 1, irqclass); |
fbb9ce95 IM |
2128 | } |
2129 | ||
2130 | /* | |
2131 | * Prove that in the backwards-direction subgraph starting at <this> | |
2132 | * there is no lock matching <mask>: | |
2133 | */ | |
2134 | static int | |
2135 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2136 | enum lock_usage_bit bit, const char *irqclass) | |
2137 | { | |
2138 | int ret; | |
d7aaba14 ML |
2139 | struct lock_list root; |
2140 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2141 | |
d7aaba14 ML |
2142 | root.parent = NULL; |
2143 | root.class = hlock_class(this); | |
2144 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2145 | if (ret < 0) |
2146 | return print_bfs_bug(ret); | |
2147 | if (ret == 1) | |
2148 | return ret; | |
fbb9ce95 | 2149 | |
24208ca7 | 2150 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2151 | this, 0, irqclass); |
fbb9ce95 IM |
2152 | } |
2153 | ||
3117df04 | 2154 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2155 | { |
2156 | printk("irq event stamp: %u\n", curr->irq_events); | |
2157 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2158 | print_ip_sym(curr->hardirq_enable_ip); | |
2159 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2160 | print_ip_sym(curr->hardirq_disable_ip); | |
2161 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2162 | print_ip_sym(curr->softirq_enable_ip); | |
2163 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2164 | print_ip_sym(curr->softirq_disable_ip); | |
2165 | } | |
2166 | ||
cd95302d | 2167 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2168 | { |
8e18257d PZ |
2169 | #if HARDIRQ_VERBOSE |
2170 | return class_filter(class); | |
2171 | #endif | |
fbb9ce95 IM |
2172 | return 0; |
2173 | } | |
2174 | ||
cd95302d | 2175 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2176 | { |
8e18257d PZ |
2177 | #if SOFTIRQ_VERBOSE |
2178 | return class_filter(class); | |
2179 | #endif | |
2180 | return 0; | |
fbb9ce95 IM |
2181 | } |
2182 | ||
cd95302d | 2183 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2184 | { |
2185 | #if RECLAIM_VERBOSE | |
2186 | return class_filter(class); | |
2187 | #endif | |
2188 | return 0; | |
2189 | } | |
2190 | ||
fbb9ce95 IM |
2191 | #define STRICT_READ_CHECKS 1 |
2192 | ||
cd95302d PZ |
2193 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2194 | #define LOCKDEP_STATE(__STATE) \ | |
2195 | __STATE##_verbose, | |
2196 | #include "lockdep_states.h" | |
2197 | #undef LOCKDEP_STATE | |
2198 | }; | |
2199 | ||
2200 | static inline int state_verbose(enum lock_usage_bit bit, | |
2201 | struct lock_class *class) | |
2202 | { | |
2203 | return state_verbose_f[bit >> 2](class); | |
2204 | } | |
2205 | ||
42c50d54 PZ |
2206 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2207 | enum lock_usage_bit bit, const char *name); | |
2208 | ||
6a6904d3 | 2209 | static int |
1c21f14e PZ |
2210 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2211 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2212 | { |
f989209e | 2213 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2214 | int read = new_bit & 1; |
42c50d54 PZ |
2215 | int dir = new_bit & 2; |
2216 | ||
38aa2714 PZ |
2217 | /* |
2218 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2219 | * has ENABLED state, which would allow recursion deadlocks. | |
2220 | * | |
2221 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2222 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2223 | */ | |
42c50d54 PZ |
2224 | check_usage_f usage = dir ? |
2225 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2226 | |
38aa2714 PZ |
2227 | /* |
2228 | * Validate that this particular lock does not have conflicting | |
2229 | * usage states. | |
2230 | */ | |
6a6904d3 PZ |
2231 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2232 | return 0; | |
42c50d54 | 2233 | |
38aa2714 PZ |
2234 | /* |
2235 | * Validate that the lock dependencies don't have conflicting usage | |
2236 | * states. | |
2237 | */ | |
2238 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2239 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2240 | return 0; |
780e820b | 2241 | |
38aa2714 PZ |
2242 | /* |
2243 | * Check for read in write conflicts | |
2244 | */ | |
2245 | if (!read) { | |
2246 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2247 | return 0; | |
2248 | ||
2249 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2250 | !usage(curr, this, excl_bit + 1, |
2251 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2252 | return 0; |
2253 | } | |
780e820b | 2254 | |
cd95302d | 2255 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2256 | return 2; |
2257 | ||
2258 | return 1; | |
2259 | } | |
2260 | ||
cf40bd16 | 2261 | enum mark_type { |
36bfb9bb PZ |
2262 | #define LOCKDEP_STATE(__STATE) __STATE, |
2263 | #include "lockdep_states.h" | |
2264 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2265 | }; |
2266 | ||
fbb9ce95 IM |
2267 | /* |
2268 | * Mark all held locks with a usage bit: | |
2269 | */ | |
1d09daa5 | 2270 | static int |
cf40bd16 | 2271 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2272 | { |
2273 | enum lock_usage_bit usage_bit; | |
2274 | struct held_lock *hlock; | |
2275 | int i; | |
2276 | ||
2277 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2278 | hlock = curr->held_locks + i; | |
2279 | ||
cf2ad4d1 PZ |
2280 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2281 | if (hlock->read) | |
2282 | usage_bit += 1; /* READ */ | |
2283 | ||
2284 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2285 | |
4ff773bb | 2286 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2287 | return 0; |
2288 | } | |
2289 | ||
2290 | return 1; | |
2291 | } | |
2292 | ||
2293 | /* | |
2294 | * Debugging helper: via this flag we know that we are in | |
2295 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2296 | */ | |
2297 | static int early_boot_irqs_enabled; | |
2298 | ||
2299 | void early_boot_irqs_off(void) | |
2300 | { | |
2301 | early_boot_irqs_enabled = 0; | |
2302 | } | |
2303 | ||
2304 | void early_boot_irqs_on(void) | |
2305 | { | |
2306 | early_boot_irqs_enabled = 1; | |
2307 | } | |
2308 | ||
2309 | /* | |
2310 | * Hardirqs will be enabled: | |
2311 | */ | |
6afe40b4 | 2312 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2313 | { |
2314 | struct task_struct *curr = current; | |
fbb9ce95 | 2315 | |
6afe40b4 | 2316 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2317 | |
fbb9ce95 IM |
2318 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2319 | return; | |
2320 | ||
2321 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2322 | return; | |
2323 | ||
2324 | if (unlikely(curr->hardirqs_enabled)) { | |
2325 | debug_atomic_inc(&redundant_hardirqs_on); | |
2326 | return; | |
2327 | } | |
2328 | /* we'll do an OFF -> ON transition: */ | |
2329 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2330 | |
2331 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2332 | return; | |
2333 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2334 | return; | |
2335 | /* | |
2336 | * We are going to turn hardirqs on, so set the | |
2337 | * usage bit for all held locks: | |
2338 | */ | |
cf40bd16 | 2339 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2340 | return; |
2341 | /* | |
2342 | * If we have softirqs enabled, then set the usage | |
2343 | * bit for all held locks. (disabled hardirqs prevented | |
2344 | * this bit from being set before) | |
2345 | */ | |
2346 | if (curr->softirqs_enabled) | |
cf40bd16 | 2347 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2348 | return; |
2349 | ||
8e18257d PZ |
2350 | curr->hardirq_enable_ip = ip; |
2351 | curr->hardirq_enable_event = ++curr->irq_events; | |
2352 | debug_atomic_inc(&hardirqs_on_events); | |
2353 | } | |
81d68a96 | 2354 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2355 | |
1d09daa5 | 2356 | void trace_hardirqs_on(void) |
81d68a96 SR |
2357 | { |
2358 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2359 | } | |
8e18257d PZ |
2360 | EXPORT_SYMBOL(trace_hardirqs_on); |
2361 | ||
2362 | /* | |
2363 | * Hardirqs were disabled: | |
2364 | */ | |
6afe40b4 | 2365 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2366 | { |
2367 | struct task_struct *curr = current; | |
2368 | ||
6afe40b4 | 2369 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2370 | |
8e18257d PZ |
2371 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2372 | return; | |
2373 | ||
2374 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2375 | return; | |
2376 | ||
2377 | if (curr->hardirqs_enabled) { | |
2378 | /* | |
2379 | * We have done an ON -> OFF transition: | |
2380 | */ | |
2381 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2382 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2383 | curr->hardirq_disable_event = ++curr->irq_events; |
2384 | debug_atomic_inc(&hardirqs_off_events); | |
2385 | } else | |
2386 | debug_atomic_inc(&redundant_hardirqs_off); | |
2387 | } | |
81d68a96 | 2388 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2389 | |
1d09daa5 | 2390 | void trace_hardirqs_off(void) |
81d68a96 SR |
2391 | { |
2392 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2393 | } | |
8e18257d PZ |
2394 | EXPORT_SYMBOL(trace_hardirqs_off); |
2395 | ||
2396 | /* | |
2397 | * Softirqs will be enabled: | |
2398 | */ | |
2399 | void trace_softirqs_on(unsigned long ip) | |
2400 | { | |
2401 | struct task_struct *curr = current; | |
2402 | ||
2403 | if (unlikely(!debug_locks)) | |
2404 | return; | |
2405 | ||
2406 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2407 | return; | |
2408 | ||
2409 | if (curr->softirqs_enabled) { | |
2410 | debug_atomic_inc(&redundant_softirqs_on); | |
2411 | return; | |
2412 | } | |
2413 | ||
2414 | /* | |
2415 | * We'll do an OFF -> ON transition: | |
2416 | */ | |
2417 | curr->softirqs_enabled = 1; | |
2418 | curr->softirq_enable_ip = ip; | |
2419 | curr->softirq_enable_event = ++curr->irq_events; | |
2420 | debug_atomic_inc(&softirqs_on_events); | |
2421 | /* | |
2422 | * We are going to turn softirqs on, so set the | |
2423 | * usage bit for all held locks, if hardirqs are | |
2424 | * enabled too: | |
2425 | */ | |
2426 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2427 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2428 | } |
2429 | ||
2430 | /* | |
2431 | * Softirqs were disabled: | |
2432 | */ | |
2433 | void trace_softirqs_off(unsigned long ip) | |
2434 | { | |
2435 | struct task_struct *curr = current; | |
2436 | ||
2437 | if (unlikely(!debug_locks)) | |
2438 | return; | |
2439 | ||
2440 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2441 | return; | |
2442 | ||
2443 | if (curr->softirqs_enabled) { | |
2444 | /* | |
2445 | * We have done an ON -> OFF transition: | |
2446 | */ | |
2447 | curr->softirqs_enabled = 0; | |
2448 | curr->softirq_disable_ip = ip; | |
2449 | curr->softirq_disable_event = ++curr->irq_events; | |
2450 | debug_atomic_inc(&softirqs_off_events); | |
2451 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2452 | } else | |
2453 | debug_atomic_inc(&redundant_softirqs_off); | |
2454 | } | |
2455 | ||
2f850181 | 2456 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2457 | { |
2458 | struct task_struct *curr = current; | |
2459 | ||
2460 | if (unlikely(!debug_locks)) | |
2461 | return; | |
2462 | ||
2463 | /* no reclaim without waiting on it */ | |
2464 | if (!(gfp_mask & __GFP_WAIT)) | |
2465 | return; | |
2466 | ||
2467 | /* this guy won't enter reclaim */ | |
2468 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2469 | return; | |
2470 | ||
2471 | /* We're only interested __GFP_FS allocations for now */ | |
2472 | if (!(gfp_mask & __GFP_FS)) | |
2473 | return; | |
2474 | ||
2f850181 | 2475 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2476 | return; |
2477 | ||
2478 | mark_held_locks(curr, RECLAIM_FS); | |
2479 | } | |
2480 | ||
2f850181 PZ |
2481 | static void check_flags(unsigned long flags); |
2482 | ||
2483 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2484 | { | |
2485 | unsigned long flags; | |
2486 | ||
2487 | if (unlikely(current->lockdep_recursion)) | |
2488 | return; | |
2489 | ||
2490 | raw_local_irq_save(flags); | |
2491 | check_flags(flags); | |
2492 | current->lockdep_recursion = 1; | |
2493 | __lockdep_trace_alloc(gfp_mask, flags); | |
2494 | current->lockdep_recursion = 0; | |
2495 | raw_local_irq_restore(flags); | |
2496 | } | |
2497 | ||
8e18257d PZ |
2498 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2499 | { | |
2500 | /* | |
2501 | * If non-trylock use in a hardirq or softirq context, then | |
2502 | * mark the lock as used in these contexts: | |
2503 | */ | |
2504 | if (!hlock->trylock) { | |
2505 | if (hlock->read) { | |
2506 | if (curr->hardirq_context) | |
2507 | if (!mark_lock(curr, hlock, | |
2508 | LOCK_USED_IN_HARDIRQ_READ)) | |
2509 | return 0; | |
2510 | if (curr->softirq_context) | |
2511 | if (!mark_lock(curr, hlock, | |
2512 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2513 | return 0; | |
2514 | } else { | |
2515 | if (curr->hardirq_context) | |
2516 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2517 | return 0; | |
2518 | if (curr->softirq_context) | |
2519 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2520 | return 0; | |
2521 | } | |
2522 | } | |
2523 | if (!hlock->hardirqs_off) { | |
2524 | if (hlock->read) { | |
2525 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2526 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2527 | return 0; |
2528 | if (curr->softirqs_enabled) | |
2529 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2530 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2531 | return 0; |
2532 | } else { | |
2533 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2534 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2535 | return 0; |
2536 | if (curr->softirqs_enabled) | |
2537 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2538 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2539 | return 0; |
2540 | } | |
2541 | } | |
2542 | ||
cf40bd16 NP |
2543 | /* |
2544 | * We reuse the irq context infrastructure more broadly as a general | |
2545 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2546 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2547 | * allocation). | |
2548 | */ | |
2549 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2550 | if (hlock->read) { | |
2551 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2552 | return 0; | |
2553 | } else { | |
2554 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2555 | return 0; | |
2556 | } | |
2557 | } | |
2558 | ||
8e18257d PZ |
2559 | return 1; |
2560 | } | |
2561 | ||
2562 | static int separate_irq_context(struct task_struct *curr, | |
2563 | struct held_lock *hlock) | |
2564 | { | |
2565 | unsigned int depth = curr->lockdep_depth; | |
2566 | ||
2567 | /* | |
2568 | * Keep track of points where we cross into an interrupt context: | |
2569 | */ | |
2570 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2571 | curr->softirq_context; | |
2572 | if (depth) { | |
2573 | struct held_lock *prev_hlock; | |
2574 | ||
2575 | prev_hlock = curr->held_locks + depth-1; | |
2576 | /* | |
2577 | * If we cross into another context, reset the | |
2578 | * hash key (this also prevents the checking and the | |
2579 | * adding of the dependency to 'prev'): | |
2580 | */ | |
2581 | if (prev_hlock->irq_context != hlock->irq_context) | |
2582 | return 1; | |
2583 | } | |
2584 | return 0; | |
fbb9ce95 IM |
2585 | } |
2586 | ||
8e18257d | 2587 | #else |
fbb9ce95 | 2588 | |
8e18257d PZ |
2589 | static inline |
2590 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2591 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2592 | { |
8e18257d PZ |
2593 | WARN_ON(1); |
2594 | return 1; | |
2595 | } | |
fbb9ce95 | 2596 | |
8e18257d PZ |
2597 | static inline int mark_irqflags(struct task_struct *curr, |
2598 | struct held_lock *hlock) | |
2599 | { | |
2600 | return 1; | |
2601 | } | |
fbb9ce95 | 2602 | |
8e18257d PZ |
2603 | static inline int separate_irq_context(struct task_struct *curr, |
2604 | struct held_lock *hlock) | |
2605 | { | |
2606 | return 0; | |
fbb9ce95 IM |
2607 | } |
2608 | ||
868a23a8 PZ |
2609 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2610 | { | |
2611 | } | |
2612 | ||
8e18257d | 2613 | #endif |
fbb9ce95 IM |
2614 | |
2615 | /* | |
8e18257d | 2616 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2617 | */ |
1d09daa5 | 2618 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2619 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2620 | { |
8e18257d | 2621 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2622 | |
2623 | /* | |
8e18257d PZ |
2624 | * If already set then do not dirty the cacheline, |
2625 | * nor do any checks: | |
fbb9ce95 | 2626 | */ |
f82b217e | 2627 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2628 | return 1; |
2629 | ||
2630 | if (!graph_lock()) | |
2631 | return 0; | |
fbb9ce95 | 2632 | /* |
8e18257d | 2633 | * Make sure we didnt race: |
fbb9ce95 | 2634 | */ |
f82b217e | 2635 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2636 | graph_unlock(); |
2637 | return 1; | |
2638 | } | |
fbb9ce95 | 2639 | |
f82b217e | 2640 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2641 | |
f82b217e | 2642 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2643 | return 0; |
fbb9ce95 | 2644 | |
8e18257d | 2645 | switch (new_bit) { |
5346417e PZ |
2646 | #define LOCKDEP_STATE(__STATE) \ |
2647 | case LOCK_USED_IN_##__STATE: \ | |
2648 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2649 | case LOCK_ENABLED_##__STATE: \ | |
2650 | case LOCK_ENABLED_##__STATE##_READ: | |
2651 | #include "lockdep_states.h" | |
2652 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2653 | ret = mark_lock_irq(curr, this, new_bit); |
2654 | if (!ret) | |
2655 | return 0; | |
2656 | break; | |
2657 | case LOCK_USED: | |
8e18257d PZ |
2658 | debug_atomic_dec(&nr_unused_locks); |
2659 | break; | |
2660 | default: | |
2661 | if (!debug_locks_off_graph_unlock()) | |
2662 | return 0; | |
2663 | WARN_ON(1); | |
2664 | return 0; | |
2665 | } | |
fbb9ce95 | 2666 | |
8e18257d PZ |
2667 | graph_unlock(); |
2668 | ||
2669 | /* | |
2670 | * We must printk outside of the graph_lock: | |
2671 | */ | |
2672 | if (ret == 2) { | |
2673 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2674 | print_lock(this); | |
2675 | print_irqtrace_events(curr); | |
2676 | dump_stack(); | |
2677 | } | |
2678 | ||
2679 | return ret; | |
2680 | } | |
fbb9ce95 IM |
2681 | |
2682 | /* | |
2683 | * Initialize a lock instance's lock-class mapping info: | |
2684 | */ | |
2685 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2686 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2687 | { |
c8a25005 PZ |
2688 | lock->class_cache = NULL; |
2689 | #ifdef CONFIG_LOCK_STAT | |
2690 | lock->cpu = raw_smp_processor_id(); | |
2691 | #endif | |
2692 | ||
2693 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2694 | lock->name = "NULL"; | |
fbb9ce95 | 2695 | return; |
c8a25005 PZ |
2696 | } |
2697 | ||
2698 | lock->name = name; | |
fbb9ce95 IM |
2699 | |
2700 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2701 | return; | |
fbb9ce95 IM |
2702 | /* |
2703 | * Sanity check, the lock-class key must be persistent: | |
2704 | */ | |
2705 | if (!static_obj(key)) { | |
2706 | printk("BUG: key %p not in .data!\n", key); | |
2707 | DEBUG_LOCKS_WARN_ON(1); | |
2708 | return; | |
2709 | } | |
fbb9ce95 | 2710 | lock->key = key; |
c8a25005 PZ |
2711 | |
2712 | if (unlikely(!debug_locks)) | |
2713 | return; | |
2714 | ||
4dfbb9d8 PZ |
2715 | if (subclass) |
2716 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2717 | } |
fbb9ce95 IM |
2718 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2719 | ||
2720 | /* | |
2721 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2722 | * We maintain the dependency maps and validate the locking attempt: | |
2723 | */ | |
2724 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2725 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
2726 | struct lockdep_map *nest_lock, unsigned long ip, |
2727 | int references) | |
fbb9ce95 IM |
2728 | { |
2729 | struct task_struct *curr = current; | |
d6d897ce | 2730 | struct lock_class *class = NULL; |
fbb9ce95 | 2731 | struct held_lock *hlock; |
fbb9ce95 IM |
2732 | unsigned int depth, id; |
2733 | int chain_head = 0; | |
bb97a91e | 2734 | int class_idx; |
fbb9ce95 IM |
2735 | u64 chain_key; |
2736 | ||
f20786ff PZ |
2737 | if (!prove_locking) |
2738 | check = 1; | |
2739 | ||
fbb9ce95 IM |
2740 | if (unlikely(!debug_locks)) |
2741 | return 0; | |
2742 | ||
2743 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2744 | return 0; | |
2745 | ||
2746 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2747 | debug_locks_off(); | |
2748 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2749 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2750 | dump_stack(); |
fbb9ce95 IM |
2751 | return 0; |
2752 | } | |
2753 | ||
d6d897ce IM |
2754 | if (!subclass) |
2755 | class = lock->class_cache; | |
2756 | /* | |
2757 | * Not cached yet or subclass? | |
2758 | */ | |
fbb9ce95 | 2759 | if (unlikely(!class)) { |
4dfbb9d8 | 2760 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2761 | if (!class) |
2762 | return 0; | |
2763 | } | |
2764 | debug_atomic_inc((atomic_t *)&class->ops); | |
2765 | if (very_verbose(class)) { | |
2766 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2767 | if (class->name_version > 1) | |
2768 | printk("#%d", class->name_version); | |
2769 | printk("\n"); | |
2770 | dump_stack(); | |
2771 | } | |
2772 | ||
2773 | /* | |
2774 | * Add the lock to the list of currently held locks. | |
2775 | * (we dont increase the depth just yet, up until the | |
2776 | * dependency checks are done) | |
2777 | */ | |
2778 | depth = curr->lockdep_depth; | |
2779 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2780 | return 0; | |
2781 | ||
bb97a91e PZ |
2782 | class_idx = class - lock_classes + 1; |
2783 | ||
2784 | if (depth) { | |
2785 | hlock = curr->held_locks + depth - 1; | |
2786 | if (hlock->class_idx == class_idx && nest_lock) { | |
2787 | if (hlock->references) | |
2788 | hlock->references++; | |
2789 | else | |
2790 | hlock->references = 2; | |
2791 | ||
2792 | return 1; | |
2793 | } | |
2794 | } | |
2795 | ||
fbb9ce95 | 2796 | hlock = curr->held_locks + depth; |
f82b217e DJ |
2797 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2798 | return 0; | |
bb97a91e | 2799 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
2800 | hlock->acquire_ip = ip; |
2801 | hlock->instance = lock; | |
7531e2f3 | 2802 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2803 | hlock->trylock = trylock; |
2804 | hlock->read = read; | |
2805 | hlock->check = check; | |
6951b12a | 2806 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 2807 | hlock->references = references; |
f20786ff PZ |
2808 | #ifdef CONFIG_LOCK_STAT |
2809 | hlock->waittime_stamp = 0; | |
3365e779 | 2810 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 2811 | #endif |
fbb9ce95 | 2812 | |
8e18257d PZ |
2813 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2814 | return 0; | |
2815 | ||
fbb9ce95 | 2816 | /* mark it as used: */ |
4ff773bb | 2817 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2818 | return 0; |
8e18257d | 2819 | |
fbb9ce95 | 2820 | /* |
17aacfb9 | 2821 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2822 | * lock keys along the dependency chain. We save the hash value |
2823 | * at every step so that we can get the current hash easily | |
2824 | * after unlock. The chain hash is then used to cache dependency | |
2825 | * results. | |
2826 | * | |
2827 | * The 'key ID' is what is the most compact key value to drive | |
2828 | * the hash, not class->key. | |
2829 | */ | |
2830 | id = class - lock_classes; | |
2831 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2832 | return 0; | |
2833 | ||
2834 | chain_key = curr->curr_chain_key; | |
2835 | if (!depth) { | |
2836 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2837 | return 0; | |
2838 | chain_head = 1; | |
2839 | } | |
2840 | ||
2841 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2842 | if (separate_irq_context(curr, hlock)) { |
2843 | chain_key = 0; | |
2844 | chain_head = 1; | |
fbb9ce95 | 2845 | } |
fbb9ce95 | 2846 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2847 | |
3aa416b0 | 2848 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2849 | return 0; |
381a2292 | 2850 | |
3aa416b0 | 2851 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2852 | curr->lockdep_depth++; |
2853 | check_chain_key(curr); | |
60e114d1 JP |
2854 | #ifdef CONFIG_DEBUG_LOCKDEP |
2855 | if (unlikely(!debug_locks)) | |
2856 | return 0; | |
2857 | #endif | |
fbb9ce95 IM |
2858 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2859 | debug_locks_off(); | |
2860 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2861 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2862 | dump_stack(); |
fbb9ce95 IM |
2863 | return 0; |
2864 | } | |
381a2292 | 2865 | |
fbb9ce95 IM |
2866 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2867 | max_lockdep_depth = curr->lockdep_depth; | |
2868 | ||
2869 | return 1; | |
2870 | } | |
2871 | ||
2872 | static int | |
2873 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2874 | unsigned long ip) | |
2875 | { | |
2876 | if (!debug_locks_off()) | |
2877 | return 0; | |
2878 | if (debug_locks_silent) | |
2879 | return 0; | |
2880 | ||
2881 | printk("\n=====================================\n"); | |
2882 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2883 | printk( "-------------------------------------\n"); | |
2884 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2885 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2886 | print_lockdep_cache(lock); |
2887 | printk(") at:\n"); | |
2888 | print_ip_sym(ip); | |
2889 | printk("but there are no more locks to release!\n"); | |
2890 | printk("\nother info that might help us debug this:\n"); | |
2891 | lockdep_print_held_locks(curr); | |
2892 | ||
2893 | printk("\nstack backtrace:\n"); | |
2894 | dump_stack(); | |
2895 | ||
2896 | return 0; | |
2897 | } | |
2898 | ||
2899 | /* | |
2900 | * Common debugging checks for both nested and non-nested unlock: | |
2901 | */ | |
2902 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2903 | unsigned long ip) | |
2904 | { | |
2905 | if (unlikely(!debug_locks)) | |
2906 | return 0; | |
2907 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2908 | return 0; | |
2909 | ||
2910 | if (curr->lockdep_depth <= 0) | |
2911 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2912 | ||
2913 | return 1; | |
2914 | } | |
2915 | ||
bb97a91e PZ |
2916 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
2917 | { | |
2918 | if (hlock->instance == lock) | |
2919 | return 1; | |
2920 | ||
2921 | if (hlock->references) { | |
2922 | struct lock_class *class = lock->class_cache; | |
2923 | ||
2924 | if (!class) | |
2925 | class = look_up_lock_class(lock, 0); | |
2926 | ||
2927 | if (DEBUG_LOCKS_WARN_ON(!class)) | |
2928 | return 0; | |
2929 | ||
2930 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) | |
2931 | return 0; | |
2932 | ||
2933 | if (hlock->class_idx == class - lock_classes + 1) | |
2934 | return 1; | |
2935 | } | |
2936 | ||
2937 | return 0; | |
2938 | } | |
2939 | ||
64aa348e | 2940 | static int |
00ef9f73 PZ |
2941 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2942 | struct lock_class_key *key, unsigned int subclass, | |
2943 | unsigned long ip) | |
64aa348e PZ |
2944 | { |
2945 | struct task_struct *curr = current; | |
2946 | struct held_lock *hlock, *prev_hlock; | |
2947 | struct lock_class *class; | |
2948 | unsigned int depth; | |
2949 | int i; | |
2950 | ||
2951 | depth = curr->lockdep_depth; | |
2952 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2953 | return 0; | |
2954 | ||
2955 | prev_hlock = NULL; | |
2956 | for (i = depth-1; i >= 0; i--) { | |
2957 | hlock = curr->held_locks + i; | |
2958 | /* | |
2959 | * We must not cross into another context: | |
2960 | */ | |
2961 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2962 | break; | |
bb97a91e | 2963 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
2964 | goto found_it; |
2965 | prev_hlock = hlock; | |
2966 | } | |
2967 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2968 | ||
2969 | found_it: | |
00ef9f73 | 2970 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2971 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2972 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2973 | |
2974 | curr->lockdep_depth = i; | |
2975 | curr->curr_chain_key = hlock->prev_chain_key; | |
2976 | ||
2977 | for (; i < depth; i++) { | |
2978 | hlock = curr->held_locks + i; | |
2979 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2980 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2981 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
2982 | hlock->nest_lock, hlock->acquire_ip, |
2983 | hlock->references)) | |
64aa348e PZ |
2984 | return 0; |
2985 | } | |
2986 | ||
2987 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2988 | return 0; | |
2989 | return 1; | |
2990 | } | |
2991 | ||
fbb9ce95 IM |
2992 | /* |
2993 | * Remove the lock to the list of currently held locks in a | |
2994 | * potentially non-nested (out of order) manner. This is a | |
2995 | * relatively rare operation, as all the unlock APIs default | |
2996 | * to nested mode (which uses lock_release()): | |
2997 | */ | |
2998 | static int | |
2999 | lock_release_non_nested(struct task_struct *curr, | |
3000 | struct lockdep_map *lock, unsigned long ip) | |
3001 | { | |
3002 | struct held_lock *hlock, *prev_hlock; | |
3003 | unsigned int depth; | |
3004 | int i; | |
3005 | ||
3006 | /* | |
3007 | * Check whether the lock exists in the current stack | |
3008 | * of held locks: | |
3009 | */ | |
3010 | depth = curr->lockdep_depth; | |
3011 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3012 | return 0; | |
3013 | ||
3014 | prev_hlock = NULL; | |
3015 | for (i = depth-1; i >= 0; i--) { | |
3016 | hlock = curr->held_locks + i; | |
3017 | /* | |
3018 | * We must not cross into another context: | |
3019 | */ | |
3020 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3021 | break; | |
bb97a91e | 3022 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3023 | goto found_it; |
3024 | prev_hlock = hlock; | |
3025 | } | |
3026 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3027 | ||
3028 | found_it: | |
bb97a91e PZ |
3029 | if (hlock->instance == lock) |
3030 | lock_release_holdtime(hlock); | |
3031 | ||
3032 | if (hlock->references) { | |
3033 | hlock->references--; | |
3034 | if (hlock->references) { | |
3035 | /* | |
3036 | * We had, and after removing one, still have | |
3037 | * references, the current lock stack is still | |
3038 | * valid. We're done! | |
3039 | */ | |
3040 | return 1; | |
3041 | } | |
3042 | } | |
f20786ff | 3043 | |
fbb9ce95 IM |
3044 | /* |
3045 | * We have the right lock to unlock, 'hlock' points to it. | |
3046 | * Now we remove it from the stack, and add back the other | |
3047 | * entries (if any), recalculating the hash along the way: | |
3048 | */ | |
bb97a91e | 3049 | |
fbb9ce95 IM |
3050 | curr->lockdep_depth = i; |
3051 | curr->curr_chain_key = hlock->prev_chain_key; | |
3052 | ||
3053 | for (i++; i < depth; i++) { | |
3054 | hlock = curr->held_locks + i; | |
3055 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3056 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3057 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3058 | hlock->nest_lock, hlock->acquire_ip, |
3059 | hlock->references)) | |
fbb9ce95 IM |
3060 | return 0; |
3061 | } | |
3062 | ||
3063 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
3064 | return 0; | |
3065 | return 1; | |
3066 | } | |
3067 | ||
3068 | /* | |
3069 | * Remove the lock to the list of currently held locks - this gets | |
3070 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3071 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3072 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3073 | */ | |
3074 | static int lock_release_nested(struct task_struct *curr, | |
3075 | struct lockdep_map *lock, unsigned long ip) | |
3076 | { | |
3077 | struct held_lock *hlock; | |
3078 | unsigned int depth; | |
3079 | ||
3080 | /* | |
3081 | * Pop off the top of the lock stack: | |
3082 | */ | |
3083 | depth = curr->lockdep_depth - 1; | |
3084 | hlock = curr->held_locks + depth; | |
3085 | ||
3086 | /* | |
3087 | * Is the unlock non-nested: | |
3088 | */ | |
bb97a91e | 3089 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3090 | return lock_release_non_nested(curr, lock, ip); |
3091 | curr->lockdep_depth--; | |
3092 | ||
3093 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
3094 | return 0; | |
3095 | ||
3096 | curr->curr_chain_key = hlock->prev_chain_key; | |
3097 | ||
f20786ff PZ |
3098 | lock_release_holdtime(hlock); |
3099 | ||
fbb9ce95 IM |
3100 | #ifdef CONFIG_DEBUG_LOCKDEP |
3101 | hlock->prev_chain_key = 0; | |
f82b217e | 3102 | hlock->class_idx = 0; |
fbb9ce95 IM |
3103 | hlock->acquire_ip = 0; |
3104 | hlock->irq_context = 0; | |
3105 | #endif | |
3106 | return 1; | |
3107 | } | |
3108 | ||
3109 | /* | |
3110 | * Remove the lock to the list of currently held locks - this gets | |
3111 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3112 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3113 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3114 | */ | |
3115 | static void | |
3116 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3117 | { | |
3118 | struct task_struct *curr = current; | |
3119 | ||
3120 | if (!check_unlock(curr, lock, ip)) | |
3121 | return; | |
3122 | ||
3123 | if (nested) { | |
3124 | if (!lock_release_nested(curr, lock, ip)) | |
3125 | return; | |
3126 | } else { | |
3127 | if (!lock_release_non_nested(curr, lock, ip)) | |
3128 | return; | |
3129 | } | |
3130 | ||
3131 | check_chain_key(curr); | |
3132 | } | |
3133 | ||
f607c668 PZ |
3134 | static int __lock_is_held(struct lockdep_map *lock) |
3135 | { | |
3136 | struct task_struct *curr = current; | |
3137 | int i; | |
3138 | ||
3139 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3140 | struct held_lock *hlock = curr->held_locks + i; |
3141 | ||
3142 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3143 | return 1; |
3144 | } | |
3145 | ||
3146 | return 0; | |
3147 | } | |
3148 | ||
fbb9ce95 IM |
3149 | /* |
3150 | * Check whether we follow the irq-flags state precisely: | |
3151 | */ | |
1d09daa5 | 3152 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3153 | { |
992860e9 IM |
3154 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3155 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3156 | if (!debug_locks) |
3157 | return; | |
3158 | ||
5f9fa8a6 IM |
3159 | if (irqs_disabled_flags(flags)) { |
3160 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3161 | printk("possible reason: unannotated irqs-off.\n"); | |
3162 | } | |
3163 | } else { | |
3164 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3165 | printk("possible reason: unannotated irqs-on.\n"); | |
3166 | } | |
3167 | } | |
fbb9ce95 IM |
3168 | |
3169 | /* | |
3170 | * We dont accurately track softirq state in e.g. | |
3171 | * hardirq contexts (such as on 4KSTACKS), so only | |
3172 | * check if not in hardirq contexts: | |
3173 | */ | |
3174 | if (!hardirq_count()) { | |
3175 | if (softirq_count()) | |
3176 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3177 | else | |
3178 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3179 | } | |
3180 | ||
3181 | if (!debug_locks) | |
3182 | print_irqtrace_events(current); | |
3183 | #endif | |
3184 | } | |
3185 | ||
00ef9f73 PZ |
3186 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3187 | struct lock_class_key *key, unsigned int subclass, | |
3188 | unsigned long ip) | |
64aa348e PZ |
3189 | { |
3190 | unsigned long flags; | |
3191 | ||
3192 | if (unlikely(current->lockdep_recursion)) | |
3193 | return; | |
3194 | ||
3195 | raw_local_irq_save(flags); | |
3196 | current->lockdep_recursion = 1; | |
3197 | check_flags(flags); | |
00ef9f73 | 3198 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3199 | check_chain_key(current); |
3200 | current->lockdep_recursion = 0; | |
3201 | raw_local_irq_restore(flags); | |
3202 | } | |
00ef9f73 | 3203 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3204 | |
fbb9ce95 IM |
3205 | /* |
3206 | * We are not always called with irqs disabled - do that here, | |
3207 | * and also avoid lockdep recursion: | |
3208 | */ | |
1d09daa5 | 3209 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3210 | int trylock, int read, int check, |
3211 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3212 | { |
3213 | unsigned long flags; | |
3214 | ||
3215 | if (unlikely(current->lockdep_recursion)) | |
3216 | return; | |
3217 | ||
3218 | raw_local_irq_save(flags); | |
3219 | check_flags(flags); | |
3220 | ||
3221 | current->lockdep_recursion = 1; | |
db2c4c77 | 3222 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3223 | __lock_acquire(lock, subclass, trylock, read, check, |
bb97a91e | 3224 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3225 | current->lockdep_recursion = 0; |
3226 | raw_local_irq_restore(flags); | |
3227 | } | |
fbb9ce95 IM |
3228 | EXPORT_SYMBOL_GPL(lock_acquire); |
3229 | ||
1d09daa5 | 3230 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3231 | unsigned long ip) |
fbb9ce95 IM |
3232 | { |
3233 | unsigned long flags; | |
3234 | ||
3235 | if (unlikely(current->lockdep_recursion)) | |
3236 | return; | |
3237 | ||
3238 | raw_local_irq_save(flags); | |
3239 | check_flags(flags); | |
3240 | current->lockdep_recursion = 1; | |
db2c4c77 | 3241 | trace_lock_release(lock, nested, ip); |
fbb9ce95 IM |
3242 | __lock_release(lock, nested, ip); |
3243 | current->lockdep_recursion = 0; | |
3244 | raw_local_irq_restore(flags); | |
3245 | } | |
fbb9ce95 IM |
3246 | EXPORT_SYMBOL_GPL(lock_release); |
3247 | ||
f607c668 PZ |
3248 | int lock_is_held(struct lockdep_map *lock) |
3249 | { | |
3250 | unsigned long flags; | |
3251 | int ret = 0; | |
3252 | ||
3253 | if (unlikely(current->lockdep_recursion)) | |
3254 | return ret; | |
3255 | ||
3256 | raw_local_irq_save(flags); | |
3257 | check_flags(flags); | |
3258 | ||
3259 | current->lockdep_recursion = 1; | |
3260 | ret = __lock_is_held(lock); | |
3261 | current->lockdep_recursion = 0; | |
3262 | raw_local_irq_restore(flags); | |
3263 | ||
3264 | return ret; | |
3265 | } | |
3266 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3267 | ||
cf40bd16 NP |
3268 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3269 | { | |
3270 | current->lockdep_reclaim_gfp = gfp_mask; | |
3271 | } | |
3272 | ||
3273 | void lockdep_clear_current_reclaim_state(void) | |
3274 | { | |
3275 | current->lockdep_reclaim_gfp = 0; | |
3276 | } | |
3277 | ||
f20786ff PZ |
3278 | #ifdef CONFIG_LOCK_STAT |
3279 | static int | |
3280 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3281 | unsigned long ip) | |
3282 | { | |
3283 | if (!debug_locks_off()) | |
3284 | return 0; | |
3285 | if (debug_locks_silent) | |
3286 | return 0; | |
3287 | ||
3288 | printk("\n=================================\n"); | |
3289 | printk( "[ BUG: bad contention detected! ]\n"); | |
3290 | printk( "---------------------------------\n"); | |
3291 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3292 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3293 | print_lockdep_cache(lock); |
3294 | printk(") at:\n"); | |
3295 | print_ip_sym(ip); | |
3296 | printk("but there are no locks held!\n"); | |
3297 | printk("\nother info that might help us debug this:\n"); | |
3298 | lockdep_print_held_locks(curr); | |
3299 | ||
3300 | printk("\nstack backtrace:\n"); | |
3301 | dump_stack(); | |
3302 | ||
3303 | return 0; | |
3304 | } | |
3305 | ||
3306 | static void | |
3307 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3308 | { | |
3309 | struct task_struct *curr = current; | |
3310 | struct held_lock *hlock, *prev_hlock; | |
3311 | struct lock_class_stats *stats; | |
3312 | unsigned int depth; | |
c7e78cff | 3313 | int i, contention_point, contending_point; |
f20786ff PZ |
3314 | |
3315 | depth = curr->lockdep_depth; | |
3316 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3317 | return; | |
3318 | ||
3319 | prev_hlock = NULL; | |
3320 | for (i = depth-1; i >= 0; i--) { | |
3321 | hlock = curr->held_locks + i; | |
3322 | /* | |
3323 | * We must not cross into another context: | |
3324 | */ | |
3325 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3326 | break; | |
bb97a91e | 3327 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3328 | goto found_it; |
3329 | prev_hlock = hlock; | |
3330 | } | |
3331 | print_lock_contention_bug(curr, lock, ip); | |
3332 | return; | |
3333 | ||
3334 | found_it: | |
bb97a91e PZ |
3335 | if (hlock->instance != lock) |
3336 | return; | |
3337 | ||
3365e779 | 3338 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3339 | |
c7e78cff PZ |
3340 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3341 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3342 | lock->ip); | |
f20786ff | 3343 | |
f82b217e | 3344 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3345 | if (contention_point < LOCKSTAT_POINTS) |
3346 | stats->contention_point[contention_point]++; | |
3347 | if (contending_point < LOCKSTAT_POINTS) | |
3348 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3349 | if (lock->cpu != smp_processor_id()) |
3350 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3351 | put_lock_stats(stats); |
3352 | } | |
3353 | ||
3354 | static void | |
c7e78cff | 3355 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3356 | { |
3357 | struct task_struct *curr = current; | |
3358 | struct held_lock *hlock, *prev_hlock; | |
3359 | struct lock_class_stats *stats; | |
3360 | unsigned int depth; | |
3365e779 | 3361 | u64 now, waittime = 0; |
96645678 | 3362 | int i, cpu; |
f20786ff PZ |
3363 | |
3364 | depth = curr->lockdep_depth; | |
3365 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3366 | return; | |
3367 | ||
3368 | prev_hlock = NULL; | |
3369 | for (i = depth-1; i >= 0; i--) { | |
3370 | hlock = curr->held_locks + i; | |
3371 | /* | |
3372 | * We must not cross into another context: | |
3373 | */ | |
3374 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3375 | break; | |
bb97a91e | 3376 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3377 | goto found_it; |
3378 | prev_hlock = hlock; | |
3379 | } | |
3380 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3381 | return; | |
3382 | ||
3383 | found_it: | |
bb97a91e PZ |
3384 | if (hlock->instance != lock) |
3385 | return; | |
3386 | ||
96645678 PZ |
3387 | cpu = smp_processor_id(); |
3388 | if (hlock->waittime_stamp) { | |
3365e779 | 3389 | now = lockstat_clock(); |
96645678 PZ |
3390 | waittime = now - hlock->waittime_stamp; |
3391 | hlock->holdtime_stamp = now; | |
3392 | } | |
f20786ff | 3393 | |
2062501a FW |
3394 | trace_lock_acquired(lock, ip, waittime); |
3395 | ||
f82b217e | 3396 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3397 | if (waittime) { |
3398 | if (hlock->read) | |
3399 | lock_time_inc(&stats->read_waittime, waittime); | |
3400 | else | |
3401 | lock_time_inc(&stats->write_waittime, waittime); | |
3402 | } | |
3403 | if (lock->cpu != cpu) | |
3404 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3405 | put_lock_stats(stats); |
96645678 PZ |
3406 | |
3407 | lock->cpu = cpu; | |
c7e78cff | 3408 | lock->ip = ip; |
f20786ff PZ |
3409 | } |
3410 | ||
3411 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3412 | { | |
3413 | unsigned long flags; | |
3414 | ||
3415 | if (unlikely(!lock_stat)) | |
3416 | return; | |
3417 | ||
3418 | if (unlikely(current->lockdep_recursion)) | |
3419 | return; | |
3420 | ||
3421 | raw_local_irq_save(flags); | |
3422 | check_flags(flags); | |
3423 | current->lockdep_recursion = 1; | |
db2c4c77 | 3424 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3425 | __lock_contended(lock, ip); |
3426 | current->lockdep_recursion = 0; | |
3427 | raw_local_irq_restore(flags); | |
3428 | } | |
3429 | EXPORT_SYMBOL_GPL(lock_contended); | |
3430 | ||
c7e78cff | 3431 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3432 | { |
3433 | unsigned long flags; | |
3434 | ||
3435 | if (unlikely(!lock_stat)) | |
3436 | return; | |
3437 | ||
3438 | if (unlikely(current->lockdep_recursion)) | |
3439 | return; | |
3440 | ||
3441 | raw_local_irq_save(flags); | |
3442 | check_flags(flags); | |
3443 | current->lockdep_recursion = 1; | |
c7e78cff | 3444 | __lock_acquired(lock, ip); |
f20786ff PZ |
3445 | current->lockdep_recursion = 0; |
3446 | raw_local_irq_restore(flags); | |
3447 | } | |
3448 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3449 | #endif | |
3450 | ||
fbb9ce95 IM |
3451 | /* |
3452 | * Used by the testsuite, sanitize the validator state | |
3453 | * after a simulated failure: | |
3454 | */ | |
3455 | ||
3456 | void lockdep_reset(void) | |
3457 | { | |
3458 | unsigned long flags; | |
23d95a03 | 3459 | int i; |
fbb9ce95 IM |
3460 | |
3461 | raw_local_irq_save(flags); | |
3462 | current->curr_chain_key = 0; | |
3463 | current->lockdep_depth = 0; | |
3464 | current->lockdep_recursion = 0; | |
3465 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3466 | nr_hardirq_chains = 0; | |
3467 | nr_softirq_chains = 0; | |
3468 | nr_process_chains = 0; | |
3469 | debug_locks = 1; | |
23d95a03 IM |
3470 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3471 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3472 | raw_local_irq_restore(flags); |
3473 | } | |
3474 | ||
3475 | static void zap_class(struct lock_class *class) | |
3476 | { | |
3477 | int i; | |
3478 | ||
3479 | /* | |
3480 | * Remove all dependencies this lock is | |
3481 | * involved in: | |
3482 | */ | |
3483 | for (i = 0; i < nr_list_entries; i++) { | |
3484 | if (list_entries[i].class == class) | |
3485 | list_del_rcu(&list_entries[i].entry); | |
3486 | } | |
3487 | /* | |
3488 | * Unhash the class and remove it from the all_lock_classes list: | |
3489 | */ | |
3490 | list_del_rcu(&class->hash_entry); | |
3491 | list_del_rcu(&class->lock_entry); | |
3492 | ||
8bfe0298 | 3493 | class->key = NULL; |
fbb9ce95 IM |
3494 | } |
3495 | ||
fabe874a | 3496 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3497 | { |
3498 | return addr >= start && addr < start + size; | |
3499 | } | |
3500 | ||
3501 | void lockdep_free_key_range(void *start, unsigned long size) | |
3502 | { | |
3503 | struct lock_class *class, *next; | |
3504 | struct list_head *head; | |
3505 | unsigned long flags; | |
3506 | int i; | |
5a26db5b | 3507 | int locked; |
fbb9ce95 IM |
3508 | |
3509 | raw_local_irq_save(flags); | |
5a26db5b | 3510 | locked = graph_lock(); |
fbb9ce95 IM |
3511 | |
3512 | /* | |
3513 | * Unhash all classes that were created by this module: | |
3514 | */ | |
3515 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3516 | head = classhash_table + i; | |
3517 | if (list_empty(head)) | |
3518 | continue; | |
fabe874a | 3519 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3520 | if (within(class->key, start, size)) |
3521 | zap_class(class); | |
fabe874a AV |
3522 | else if (within(class->name, start, size)) |
3523 | zap_class(class); | |
3524 | } | |
fbb9ce95 IM |
3525 | } |
3526 | ||
5a26db5b NP |
3527 | if (locked) |
3528 | graph_unlock(); | |
fbb9ce95 IM |
3529 | raw_local_irq_restore(flags); |
3530 | } | |
3531 | ||
3532 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3533 | { | |
d6d897ce | 3534 | struct lock_class *class, *next; |
fbb9ce95 IM |
3535 | struct list_head *head; |
3536 | unsigned long flags; | |
3537 | int i, j; | |
5a26db5b | 3538 | int locked; |
fbb9ce95 IM |
3539 | |
3540 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3541 | |
3542 | /* | |
d6d897ce IM |
3543 | * Remove all classes this lock might have: |
3544 | */ | |
3545 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3546 | /* | |
3547 | * If the class exists we look it up and zap it: | |
3548 | */ | |
3549 | class = look_up_lock_class(lock, j); | |
3550 | if (class) | |
3551 | zap_class(class); | |
3552 | } | |
3553 | /* | |
3554 | * Debug check: in the end all mapped classes should | |
3555 | * be gone. | |
fbb9ce95 | 3556 | */ |
5a26db5b | 3557 | locked = graph_lock(); |
fbb9ce95 IM |
3558 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3559 | head = classhash_table + i; | |
3560 | if (list_empty(head)) | |
3561 | continue; | |
3562 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3563 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3564 | if (debug_locks_off_graph_unlock()) |
3565 | WARN_ON(1); | |
d6d897ce | 3566 | goto out_restore; |
fbb9ce95 IM |
3567 | } |
3568 | } | |
3569 | } | |
5a26db5b NP |
3570 | if (locked) |
3571 | graph_unlock(); | |
d6d897ce IM |
3572 | |
3573 | out_restore: | |
fbb9ce95 IM |
3574 | raw_local_irq_restore(flags); |
3575 | } | |
3576 | ||
1499993c | 3577 | void lockdep_init(void) |
fbb9ce95 IM |
3578 | { |
3579 | int i; | |
3580 | ||
3581 | /* | |
3582 | * Some architectures have their own start_kernel() | |
3583 | * code which calls lockdep_init(), while we also | |
3584 | * call lockdep_init() from the start_kernel() itself, | |
3585 | * and we want to initialize the hashes only once: | |
3586 | */ | |
3587 | if (lockdep_initialized) | |
3588 | return; | |
3589 | ||
3590 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3591 | INIT_LIST_HEAD(classhash_table + i); | |
3592 | ||
3593 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3594 | INIT_LIST_HEAD(chainhash_table + i); | |
3595 | ||
3596 | lockdep_initialized = 1; | |
3597 | } | |
3598 | ||
3599 | void __init lockdep_info(void) | |
3600 | { | |
3601 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3602 | ||
b0788caf | 3603 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3604 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3605 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3606 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3607 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3608 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3609 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3610 | ||
3611 | printk(" memory used by lock dependency info: %lu kB\n", | |
3612 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3613 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3614 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3615 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 3616 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 3617 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 3618 | + sizeof(struct circular_queue) |
4dd861d6 | 3619 | #endif |
90629209 | 3620 | ) / 1024 |
4dd861d6 | 3621 | ); |
fbb9ce95 IM |
3622 | |
3623 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3624 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3625 | ||
3626 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3627 | if (lockdep_init_error) { |
3628 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3629 | printk("Call stack leading to lockdep invocation was:\n"); | |
3630 | print_stack_trace(&lockdep_init_trace, 0); | |
3631 | } | |
fbb9ce95 IM |
3632 | #endif |
3633 | } | |
3634 | ||
fbb9ce95 IM |
3635 | static void |
3636 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3637 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3638 | { |
3639 | if (!debug_locks_off()) | |
3640 | return; | |
3641 | if (debug_locks_silent) | |
3642 | return; | |
3643 | ||
3644 | printk("\n=========================\n"); | |
3645 | printk( "[ BUG: held lock freed! ]\n"); | |
3646 | printk( "-------------------------\n"); | |
3647 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3648 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3649 | print_lock(hlock); |
fbb9ce95 IM |
3650 | lockdep_print_held_locks(curr); |
3651 | ||
3652 | printk("\nstack backtrace:\n"); | |
3653 | dump_stack(); | |
3654 | } | |
3655 | ||
54561783 ON |
3656 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3657 | const void* lock_from, unsigned long lock_len) | |
3658 | { | |
3659 | return lock_from + lock_len <= mem_from || | |
3660 | mem_from + mem_len <= lock_from; | |
3661 | } | |
3662 | ||
fbb9ce95 IM |
3663 | /* |
3664 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3665 | * is destroyed or reinitialized - this code checks whether there is | |
3666 | * any held lock in the memory range of <from> to <to>: | |
3667 | */ | |
3668 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3669 | { | |
fbb9ce95 IM |
3670 | struct task_struct *curr = current; |
3671 | struct held_lock *hlock; | |
3672 | unsigned long flags; | |
3673 | int i; | |
3674 | ||
3675 | if (unlikely(!debug_locks)) | |
3676 | return; | |
3677 | ||
3678 | local_irq_save(flags); | |
3679 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3680 | hlock = curr->held_locks + i; | |
3681 | ||
54561783 ON |
3682 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3683 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3684 | continue; |
3685 | ||
54561783 | 3686 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3687 | break; |
3688 | } | |
3689 | local_irq_restore(flags); | |
3690 | } | |
ed07536e | 3691 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3692 | |
3693 | static void print_held_locks_bug(struct task_struct *curr) | |
3694 | { | |
3695 | if (!debug_locks_off()) | |
3696 | return; | |
3697 | if (debug_locks_silent) | |
3698 | return; | |
3699 | ||
3700 | printk("\n=====================================\n"); | |
3701 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3702 | printk( "-------------------------------------\n"); | |
3703 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3704 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3705 | lockdep_print_held_locks(curr); |
3706 | ||
3707 | printk("\nstack backtrace:\n"); | |
3708 | dump_stack(); | |
3709 | } | |
3710 | ||
3711 | void debug_check_no_locks_held(struct task_struct *task) | |
3712 | { | |
3713 | if (unlikely(task->lockdep_depth > 0)) | |
3714 | print_held_locks_bug(task); | |
3715 | } | |
3716 | ||
3717 | void debug_show_all_locks(void) | |
3718 | { | |
3719 | struct task_struct *g, *p; | |
3720 | int count = 10; | |
3721 | int unlock = 1; | |
3722 | ||
9c35dd7f JP |
3723 | if (unlikely(!debug_locks)) { |
3724 | printk("INFO: lockdep is turned off.\n"); | |
3725 | return; | |
3726 | } | |
fbb9ce95 IM |
3727 | printk("\nShowing all locks held in the system:\n"); |
3728 | ||
3729 | /* | |
3730 | * Here we try to get the tasklist_lock as hard as possible, | |
3731 | * if not successful after 2 seconds we ignore it (but keep | |
3732 | * trying). This is to enable a debug printout even if a | |
3733 | * tasklist_lock-holding task deadlocks or crashes. | |
3734 | */ | |
3735 | retry: | |
3736 | if (!read_trylock(&tasklist_lock)) { | |
3737 | if (count == 10) | |
3738 | printk("hm, tasklist_lock locked, retrying... "); | |
3739 | if (count) { | |
3740 | count--; | |
3741 | printk(" #%d", 10-count); | |
3742 | mdelay(200); | |
3743 | goto retry; | |
3744 | } | |
3745 | printk(" ignoring it.\n"); | |
3746 | unlock = 0; | |
46fec7ac | 3747 | } else { |
3748 | if (count != 10) | |
3749 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3750 | } |
fbb9ce95 IM |
3751 | |
3752 | do_each_thread(g, p) { | |
85684873 IM |
3753 | /* |
3754 | * It's not reliable to print a task's held locks | |
3755 | * if it's not sleeping (or if it's not the current | |
3756 | * task): | |
3757 | */ | |
3758 | if (p->state == TASK_RUNNING && p != current) | |
3759 | continue; | |
fbb9ce95 IM |
3760 | if (p->lockdep_depth) |
3761 | lockdep_print_held_locks(p); | |
3762 | if (!unlock) | |
3763 | if (read_trylock(&tasklist_lock)) | |
3764 | unlock = 1; | |
3765 | } while_each_thread(g, p); | |
3766 | ||
3767 | printk("\n"); | |
3768 | printk("=============================================\n\n"); | |
3769 | ||
3770 | if (unlock) | |
3771 | read_unlock(&tasklist_lock); | |
3772 | } | |
fbb9ce95 IM |
3773 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3774 | ||
82a1fcb9 IM |
3775 | /* |
3776 | * Careful: only use this function if you are sure that | |
3777 | * the task cannot run in parallel! | |
3778 | */ | |
3779 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3780 | { |
9c35dd7f JP |
3781 | if (unlikely(!debug_locks)) { |
3782 | printk("INFO: lockdep is turned off.\n"); | |
3783 | return; | |
3784 | } | |
fbb9ce95 IM |
3785 | lockdep_print_held_locks(task); |
3786 | } | |
82a1fcb9 IM |
3787 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3788 | ||
3789 | void debug_show_held_locks(struct task_struct *task) | |
3790 | { | |
3791 | __debug_show_held_locks(task); | |
3792 | } | |
fbb9ce95 | 3793 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3794 | |
3795 | void lockdep_sys_exit(void) | |
3796 | { | |
3797 | struct task_struct *curr = current; | |
3798 | ||
3799 | if (unlikely(curr->lockdep_depth)) { | |
3800 | if (!debug_locks_off()) | |
3801 | return; | |
3802 | printk("\n================================================\n"); | |
3803 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3804 | printk( "------------------------------------------------\n"); | |
3805 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3806 | curr->comm, curr->pid); | |
3807 | lockdep_print_held_locks(curr); | |
3808 | } | |
3809 | } | |
0632eb3d PM |
3810 | |
3811 | void lockdep_rcu_dereference(const char *file, const int line) | |
3812 | { | |
3813 | struct task_struct *curr = current; | |
3814 | ||
3815 | if (!debug_locks_off()) | |
3816 | return; | |
056ba4a9 PM |
3817 | printk("\n===================================================\n"); |
3818 | printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n"); | |
3819 | printk( "---------------------------------------------------\n"); | |
0632eb3d PM |
3820 | printk("%s:%d invoked rcu_dereference_check() without protection!\n", |
3821 | file, line); | |
3822 | printk("\nother info that might help us debug this:\n\n"); | |
cc5b83a9 | 3823 | printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks); |
0632eb3d PM |
3824 | lockdep_print_held_locks(curr); |
3825 | printk("\nstack backtrace:\n"); | |
3826 | dump_stack(); | |
3827 | } | |
3828 | EXPORT_SYMBOL_GPL(lockdep_rcu_dereference); |