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> |
d3d03d4f | 47 | #include <linux/kmemcheck.h> |
af012961 | 48 | |
fbb9ce95 IM |
49 | #include <asm/sections.h> |
50 | ||
51 | #include "lockdep_internals.h" | |
52 | ||
a8d154b0 | 53 | #define CREATE_TRACE_POINTS |
67178767 | 54 | #include <trace/events/lock.h> |
a8d154b0 | 55 | |
f20786ff PZ |
56 | #ifdef CONFIG_PROVE_LOCKING |
57 | int prove_locking = 1; | |
58 | module_param(prove_locking, int, 0644); | |
59 | #else | |
60 | #define prove_locking 0 | |
61 | #endif | |
62 | ||
63 | #ifdef CONFIG_LOCK_STAT | |
64 | int lock_stat = 1; | |
65 | module_param(lock_stat, int, 0644); | |
66 | #else | |
67 | #define lock_stat 0 | |
68 | #endif | |
69 | ||
fbb9ce95 | 70 | /* |
74c383f1 IM |
71 | * lockdep_lock: protects the lockdep graph, the hashes and the |
72 | * class/list/hash allocators. | |
fbb9ce95 IM |
73 | * |
74 | * This is one of the rare exceptions where it's justified | |
75 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 76 | * code to recurse back into the lockdep code... |
fbb9ce95 | 77 | */ |
edc35bd7 | 78 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
79 | |
80 | static int graph_lock(void) | |
81 | { | |
0199c4e6 | 82 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
83 | /* |
84 | * Make sure that if another CPU detected a bug while | |
85 | * walking the graph we dont change it (while the other | |
86 | * CPU is busy printing out stuff with the graph lock | |
87 | * dropped already) | |
88 | */ | |
89 | if (!debug_locks) { | |
0199c4e6 | 90 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
91 | return 0; |
92 | } | |
bb065afb SR |
93 | /* prevent any recursions within lockdep from causing deadlocks */ |
94 | current->lockdep_recursion++; | |
74c383f1 IM |
95 | return 1; |
96 | } | |
97 | ||
98 | static inline int graph_unlock(void) | |
99 | { | |
0119fee4 PZ |
100 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
101 | /* | |
102 | * The lockdep graph lock isn't locked while we expect it to | |
103 | * be, we're confused now, bye! | |
104 | */ | |
381a2292 | 105 | return DEBUG_LOCKS_WARN_ON(1); |
0119fee4 | 106 | } |
381a2292 | 107 | |
bb065afb | 108 | current->lockdep_recursion--; |
0199c4e6 | 109 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
110 | return 0; |
111 | } | |
112 | ||
113 | /* | |
114 | * Turn lock debugging off and return with 0 if it was off already, | |
115 | * and also release the graph lock: | |
116 | */ | |
117 | static inline int debug_locks_off_graph_unlock(void) | |
118 | { | |
119 | int ret = debug_locks_off(); | |
120 | ||
0199c4e6 | 121 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
122 | |
123 | return ret; | |
124 | } | |
fbb9ce95 IM |
125 | |
126 | static int lockdep_initialized; | |
127 | ||
128 | unsigned long nr_list_entries; | |
af012961 | 129 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 130 | |
fbb9ce95 IM |
131 | /* |
132 | * All data structures here are protected by the global debug_lock. | |
133 | * | |
134 | * Mutex key structs only get allocated, once during bootup, and never | |
135 | * get freed - this significantly simplifies the debugging code. | |
136 | */ | |
137 | unsigned long nr_lock_classes; | |
138 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
139 | ||
f82b217e DJ |
140 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
141 | { | |
142 | if (!hlock->class_idx) { | |
0119fee4 PZ |
143 | /* |
144 | * Someone passed in garbage, we give up. | |
145 | */ | |
f82b217e DJ |
146 | DEBUG_LOCKS_WARN_ON(1); |
147 | return NULL; | |
148 | } | |
149 | return lock_classes + hlock->class_idx - 1; | |
150 | } | |
151 | ||
f20786ff | 152 | #ifdef CONFIG_LOCK_STAT |
1871e52c TH |
153 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
154 | cpu_lock_stats); | |
f20786ff | 155 | |
3365e779 PZ |
156 | static inline u64 lockstat_clock(void) |
157 | { | |
c676329a | 158 | return local_clock(); |
3365e779 PZ |
159 | } |
160 | ||
c7e78cff | 161 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
162 | { |
163 | int i; | |
164 | ||
c7e78cff PZ |
165 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
166 | if (points[i] == 0) { | |
167 | points[i] = ip; | |
f20786ff PZ |
168 | break; |
169 | } | |
c7e78cff | 170 | if (points[i] == ip) |
f20786ff PZ |
171 | break; |
172 | } | |
173 | ||
174 | return i; | |
175 | } | |
176 | ||
3365e779 | 177 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
178 | { |
179 | if (time > lt->max) | |
180 | lt->max = time; | |
181 | ||
109d71c6 | 182 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
183 | lt->min = time; |
184 | ||
185 | lt->total += time; | |
186 | lt->nr++; | |
187 | } | |
188 | ||
c46261de PZ |
189 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
190 | { | |
109d71c6 FR |
191 | if (!src->nr) |
192 | return; | |
193 | ||
194 | if (src->max > dst->max) | |
195 | dst->max = src->max; | |
196 | ||
197 | if (src->min < dst->min || !dst->nr) | |
198 | dst->min = src->min; | |
199 | ||
c46261de PZ |
200 | dst->total += src->total; |
201 | dst->nr += src->nr; | |
202 | } | |
203 | ||
204 | struct lock_class_stats lock_stats(struct lock_class *class) | |
205 | { | |
206 | struct lock_class_stats stats; | |
207 | int cpu, i; | |
208 | ||
209 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
210 | for_each_possible_cpu(cpu) { | |
211 | struct lock_class_stats *pcs = | |
1871e52c | 212 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
213 | |
214 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
215 | stats.contention_point[i] += pcs->contention_point[i]; | |
216 | ||
c7e78cff PZ |
217 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
218 | stats.contending_point[i] += pcs->contending_point[i]; | |
219 | ||
c46261de PZ |
220 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
221 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
222 | ||
223 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
224 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
225 | |
226 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
227 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
228 | } |
229 | ||
230 | return stats; | |
231 | } | |
232 | ||
233 | void clear_lock_stats(struct lock_class *class) | |
234 | { | |
235 | int cpu; | |
236 | ||
237 | for_each_possible_cpu(cpu) { | |
238 | struct lock_class_stats *cpu_stats = | |
1871e52c | 239 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
240 | |
241 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
242 | } | |
243 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 244 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
245 | } |
246 | ||
f20786ff PZ |
247 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
248 | { | |
1871e52c | 249 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
250 | } |
251 | ||
252 | static void put_lock_stats(struct lock_class_stats *stats) | |
253 | { | |
1871e52c | 254 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
255 | } |
256 | ||
257 | static void lock_release_holdtime(struct held_lock *hlock) | |
258 | { | |
259 | struct lock_class_stats *stats; | |
3365e779 | 260 | u64 holdtime; |
f20786ff PZ |
261 | |
262 | if (!lock_stat) | |
263 | return; | |
264 | ||
3365e779 | 265 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 266 | |
f82b217e | 267 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
268 | if (hlock->read) |
269 | lock_time_inc(&stats->read_holdtime, holdtime); | |
270 | else | |
271 | lock_time_inc(&stats->write_holdtime, holdtime); | |
272 | put_lock_stats(stats); | |
273 | } | |
274 | #else | |
275 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
276 | { | |
277 | } | |
278 | #endif | |
279 | ||
fbb9ce95 IM |
280 | /* |
281 | * We keep a global list of all lock classes. The list only grows, | |
282 | * never shrinks. The list is only accessed with the lockdep | |
283 | * spinlock lock held. | |
284 | */ | |
285 | LIST_HEAD(all_lock_classes); | |
286 | ||
287 | /* | |
288 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
289 | */ | |
290 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
291 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 292 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
293 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
294 | ||
295 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
296 | ||
fbb9ce95 IM |
297 | /* |
298 | * We put the lock dependency chains into a hash-table as well, to cache | |
299 | * their existence: | |
300 | */ | |
301 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
302 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 303 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
304 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
305 | ||
306 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
307 | ||
308 | /* | |
309 | * The hash key of the lock dependency chains is a hash itself too: | |
310 | * it's a hash of all locks taken up to that lock, including that lock. | |
311 | * It's a 64-bit hash, because it's important for the keys to be | |
312 | * unique. | |
313 | */ | |
314 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
315 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
316 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
317 | (key2)) |
318 | ||
1d09daa5 | 319 | void lockdep_off(void) |
fbb9ce95 IM |
320 | { |
321 | current->lockdep_recursion++; | |
322 | } | |
fbb9ce95 IM |
323 | EXPORT_SYMBOL(lockdep_off); |
324 | ||
1d09daa5 | 325 | void lockdep_on(void) |
fbb9ce95 IM |
326 | { |
327 | current->lockdep_recursion--; | |
328 | } | |
fbb9ce95 IM |
329 | EXPORT_SYMBOL(lockdep_on); |
330 | ||
fbb9ce95 IM |
331 | /* |
332 | * Debugging switches: | |
333 | */ | |
334 | ||
335 | #define VERBOSE 0 | |
33e94e96 | 336 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
337 | |
338 | #if VERBOSE | |
339 | # define HARDIRQ_VERBOSE 1 | |
340 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 341 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
342 | #else |
343 | # define HARDIRQ_VERBOSE 0 | |
344 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 345 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
346 | #endif |
347 | ||
cf40bd16 | 348 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
349 | /* |
350 | * Quick filtering for interesting events: | |
351 | */ | |
352 | static int class_filter(struct lock_class *class) | |
353 | { | |
f9829cce AK |
354 | #if 0 |
355 | /* Example */ | |
fbb9ce95 | 356 | if (class->name_version == 1 && |
f9829cce | 357 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
358 | return 1; |
359 | if (class->name_version == 1 && | |
f9829cce | 360 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 361 | return 1; |
f9829cce | 362 | #endif |
a6640897 IM |
363 | /* Filter everything else. 1 would be to allow everything else */ |
364 | return 0; | |
fbb9ce95 IM |
365 | } |
366 | #endif | |
367 | ||
368 | static int verbose(struct lock_class *class) | |
369 | { | |
370 | #if VERBOSE | |
371 | return class_filter(class); | |
372 | #endif | |
373 | return 0; | |
374 | } | |
375 | ||
fbb9ce95 IM |
376 | /* |
377 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 378 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
379 | */ |
380 | unsigned long nr_stack_trace_entries; | |
381 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
382 | ||
2c522836 DJ |
383 | static void print_lockdep_off(const char *bug_msg) |
384 | { | |
385 | printk(KERN_DEBUG "%s\n", bug_msg); | |
386 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); | |
acf59377 | 387 | #ifdef CONFIG_LOCK_STAT |
2c522836 | 388 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
acf59377 | 389 | #endif |
2c522836 DJ |
390 | } |
391 | ||
fbb9ce95 IM |
392 | static int save_trace(struct stack_trace *trace) |
393 | { | |
394 | trace->nr_entries = 0; | |
395 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
396 | trace->entries = stack_trace + nr_stack_trace_entries; | |
397 | ||
5a1b3999 | 398 | trace->skip = 3; |
5a1b3999 | 399 | |
ab1b6f03 | 400 | save_stack_trace(trace); |
fbb9ce95 | 401 | |
4f84f433 PZ |
402 | /* |
403 | * Some daft arches put -1 at the end to indicate its a full trace. | |
404 | * | |
405 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
406 | * complete trace that maxes out the entries provided will be reported | |
407 | * as incomplete, friggin useless </rant> | |
408 | */ | |
ea5b41f9 LT |
409 | if (trace->nr_entries != 0 && |
410 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
411 | trace->nr_entries--; |
412 | ||
fbb9ce95 IM |
413 | trace->max_entries = trace->nr_entries; |
414 | ||
415 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 416 | |
4f84f433 | 417 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
418 | if (!debug_locks_off_graph_unlock()) |
419 | return 0; | |
420 | ||
2c522836 | 421 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
74c383f1 IM |
422 | dump_stack(); |
423 | ||
fbb9ce95 IM |
424 | return 0; |
425 | } | |
426 | ||
427 | return 1; | |
428 | } | |
429 | ||
430 | unsigned int nr_hardirq_chains; | |
431 | unsigned int nr_softirq_chains; | |
432 | unsigned int nr_process_chains; | |
433 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
434 | |
435 | #ifdef CONFIG_DEBUG_LOCKDEP | |
436 | /* | |
437 | * We cannot printk in early bootup code. Not even early_printk() | |
438 | * might work. So we mark any initialization errors and printk | |
439 | * about it later on, in lockdep_info(). | |
440 | */ | |
441 | static int lockdep_init_error; | |
81140acc | 442 | static const char *lock_init_error; |
c71063c9 JB |
443 | static unsigned long lockdep_init_trace_data[20]; |
444 | static struct stack_trace lockdep_init_trace = { | |
445 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
446 | .entries = lockdep_init_trace_data, | |
447 | }; | |
fbb9ce95 IM |
448 | |
449 | /* | |
450 | * Various lockdep statistics: | |
451 | */ | |
bd6d29c2 | 452 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
453 | #endif |
454 | ||
455 | /* | |
456 | * Locking printouts: | |
457 | */ | |
458 | ||
fabe9c42 | 459 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
460 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
461 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
462 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
463 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 464 | |
fbb9ce95 IM |
465 | static const char *usage_str[] = |
466 | { | |
fabe9c42 PZ |
467 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
468 | #include "lockdep_states.h" | |
469 | #undef LOCKDEP_STATE | |
470 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
471 | }; |
472 | ||
473 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
474 | { | |
ffb45122 | 475 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
476 | } |
477 | ||
3ff176ca | 478 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 479 | { |
3ff176ca PZ |
480 | return 1UL << bit; |
481 | } | |
fbb9ce95 | 482 | |
3ff176ca PZ |
483 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
484 | { | |
485 | char c = '.'; | |
486 | ||
487 | if (class->usage_mask & lock_flag(bit + 2)) | |
488 | c = '+'; | |
489 | if (class->usage_mask & lock_flag(bit)) { | |
490 | c = '-'; | |
491 | if (class->usage_mask & lock_flag(bit + 2)) | |
492 | c = '?'; | |
fbb9ce95 IM |
493 | } |
494 | ||
3ff176ca PZ |
495 | return c; |
496 | } | |
cf40bd16 | 497 | |
f510b233 | 498 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 499 | { |
f510b233 | 500 | int i = 0; |
cf40bd16 | 501 | |
f510b233 PZ |
502 | #define LOCKDEP_STATE(__STATE) \ |
503 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
504 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
505 | #include "lockdep_states.h" | |
506 | #undef LOCKDEP_STATE | |
507 | ||
508 | usage[i] = '\0'; | |
fbb9ce95 IM |
509 | } |
510 | ||
e5e78d08 | 511 | static void __print_lock_name(struct lock_class *class) |
3003eba3 SR |
512 | { |
513 | char str[KSYM_NAME_LEN]; | |
514 | const char *name; | |
515 | ||
fbb9ce95 IM |
516 | name = class->name; |
517 | if (!name) { | |
518 | name = __get_key_name(class->key, str); | |
e5e78d08 | 519 | printk("%s", name); |
fbb9ce95 | 520 | } else { |
e5e78d08 | 521 | printk("%s", name); |
fbb9ce95 IM |
522 | if (class->name_version > 1) |
523 | printk("#%d", class->name_version); | |
524 | if (class->subclass) | |
525 | printk("/%d", class->subclass); | |
526 | } | |
e5e78d08 SR |
527 | } |
528 | ||
529 | static void print_lock_name(struct lock_class *class) | |
530 | { | |
531 | char usage[LOCK_USAGE_CHARS]; | |
532 | ||
533 | get_usage_chars(class, usage); | |
534 | ||
535 | printk(" ("); | |
536 | __print_lock_name(class); | |
f510b233 | 537 | printk("){%s}", usage); |
fbb9ce95 IM |
538 | } |
539 | ||
540 | static void print_lockdep_cache(struct lockdep_map *lock) | |
541 | { | |
542 | const char *name; | |
9281acea | 543 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
544 | |
545 | name = lock->name; | |
546 | if (!name) | |
547 | name = __get_key_name(lock->key->subkeys, str); | |
548 | ||
549 | printk("%s", name); | |
550 | } | |
551 | ||
552 | static void print_lock(struct held_lock *hlock) | |
553 | { | |
d7bc3197 PZ |
554 | /* |
555 | * We can be called locklessly through debug_show_all_locks() so be | |
556 | * extra careful, the hlock might have been released and cleared. | |
557 | */ | |
558 | unsigned int class_idx = hlock->class_idx; | |
559 | ||
560 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ | |
561 | barrier(); | |
562 | ||
563 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { | |
564 | printk("<RELEASED>\n"); | |
565 | return; | |
566 | } | |
567 | ||
568 | print_lock_name(lock_classes + class_idx - 1); | |
fbb9ce95 IM |
569 | printk(", at: "); |
570 | print_ip_sym(hlock->acquire_ip); | |
571 | } | |
572 | ||
573 | static void lockdep_print_held_locks(struct task_struct *curr) | |
574 | { | |
575 | int i, depth = curr->lockdep_depth; | |
576 | ||
577 | if (!depth) { | |
ba25f9dc | 578 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
579 | return; |
580 | } | |
581 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 582 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
583 | |
584 | for (i = 0; i < depth; i++) { | |
585 | printk(" #%d: ", i); | |
586 | print_lock(curr->held_locks + i); | |
587 | } | |
588 | } | |
fbb9ce95 | 589 | |
fbdc4b9a | 590 | static void print_kernel_ident(void) |
8e18257d | 591 | { |
fbdc4b9a | 592 | printk("%s %.*s %s\n", init_utsname()->release, |
8e18257d | 593 | (int)strcspn(init_utsname()->version, " "), |
fbdc4b9a BH |
594 | init_utsname()->version, |
595 | print_tainted()); | |
8e18257d PZ |
596 | } |
597 | ||
598 | static int very_verbose(struct lock_class *class) | |
599 | { | |
600 | #if VERY_VERBOSE | |
601 | return class_filter(class); | |
602 | #endif | |
603 | return 0; | |
604 | } | |
605 | ||
fbb9ce95 | 606 | /* |
8e18257d | 607 | * Is this the address of a static object: |
fbb9ce95 | 608 | */ |
8dce7a9a | 609 | #ifdef __KERNEL__ |
8e18257d | 610 | static int static_obj(void *obj) |
fbb9ce95 | 611 | { |
8e18257d PZ |
612 | unsigned long start = (unsigned long) &_stext, |
613 | end = (unsigned long) &_end, | |
614 | addr = (unsigned long) obj; | |
8e18257d | 615 | |
fbb9ce95 | 616 | /* |
8e18257d | 617 | * static variable? |
fbb9ce95 | 618 | */ |
8e18257d PZ |
619 | if ((addr >= start) && (addr < end)) |
620 | return 1; | |
fbb9ce95 | 621 | |
2a9ad18d MF |
622 | if (arch_is_kernel_data(addr)) |
623 | return 1; | |
624 | ||
fbb9ce95 | 625 | /* |
10fad5e4 | 626 | * in-kernel percpu var? |
fbb9ce95 | 627 | */ |
10fad5e4 TH |
628 | if (is_kernel_percpu_address(addr)) |
629 | return 1; | |
fbb9ce95 | 630 | |
8e18257d | 631 | /* |
10fad5e4 | 632 | * module static or percpu var? |
8e18257d | 633 | */ |
10fad5e4 | 634 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a | 635 | } |
8dce7a9a | 636 | #endif |
99de055a | 637 | |
fbb9ce95 | 638 | /* |
8e18257d PZ |
639 | * To make lock name printouts unique, we calculate a unique |
640 | * class->name_version generation counter: | |
fbb9ce95 | 641 | */ |
8e18257d | 642 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 643 | { |
8e18257d PZ |
644 | struct lock_class *class; |
645 | int count = 0; | |
fbb9ce95 | 646 | |
8e18257d | 647 | if (!new_class->name) |
fbb9ce95 IM |
648 | return 0; |
649 | ||
35a9393c | 650 | list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) { |
8e18257d PZ |
651 | if (new_class->key - new_class->subclass == class->key) |
652 | return class->name_version; | |
653 | if (class->name && !strcmp(class->name, new_class->name)) | |
654 | count = max(count, class->name_version); | |
655 | } | |
fbb9ce95 | 656 | |
8e18257d | 657 | return count + 1; |
fbb9ce95 IM |
658 | } |
659 | ||
8e18257d PZ |
660 | /* |
661 | * Register a lock's class in the hash-table, if the class is not present | |
662 | * yet. Otherwise we look it up. We cache the result in the lock object | |
663 | * itself, so actual lookup of the hash should be once per lock object. | |
664 | */ | |
665 | static inline struct lock_class * | |
666 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 667 | { |
8e18257d PZ |
668 | struct lockdep_subclass_key *key; |
669 | struct list_head *hash_head; | |
670 | struct lock_class *class; | |
fbb9ce95 | 671 | |
8e18257d PZ |
672 | #ifdef CONFIG_DEBUG_LOCKDEP |
673 | /* | |
674 | * If the architecture calls into lockdep before initializing | |
675 | * the hashes then we'll warn about it later. (we cannot printk | |
676 | * right now) | |
677 | */ | |
678 | if (unlikely(!lockdep_initialized)) { | |
679 | lockdep_init(); | |
680 | lockdep_init_error = 1; | |
81140acc | 681 | lock_init_error = lock->name; |
c71063c9 | 682 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
683 | } |
684 | #endif | |
fbb9ce95 | 685 | |
4ba053c0 HM |
686 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
687 | debug_locks_off(); | |
688 | printk(KERN_ERR | |
689 | "BUG: looking up invalid subclass: %u\n", subclass); | |
690 | printk(KERN_ERR | |
691 | "turning off the locking correctness validator.\n"); | |
692 | dump_stack(); | |
693 | return NULL; | |
694 | } | |
695 | ||
8e18257d PZ |
696 | /* |
697 | * Static locks do not have their class-keys yet - for them the key | |
698 | * is the lock object itself: | |
699 | */ | |
700 | if (unlikely(!lock->key)) | |
701 | lock->key = (void *)lock; | |
fbb9ce95 | 702 | |
8e18257d PZ |
703 | /* |
704 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
705 | * lock_class_key variable is passed in through the mutex_init() | |
706 | * (or spin_lock_init()) call - which acts as the key. For static | |
707 | * locks we use the lock object itself as the key. | |
708 | */ | |
4b32d0a4 PZ |
709 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
710 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 711 | |
8e18257d | 712 | key = lock->key->subkeys + subclass; |
ca268c69 | 713 | |
8e18257d | 714 | hash_head = classhashentry(key); |
74c383f1 | 715 | |
8e18257d | 716 | /* |
35a9393c | 717 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
8e18257d | 718 | */ |
35a9393c PZ |
719 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
720 | return NULL; | |
721 | ||
722 | list_for_each_entry_rcu(class, hash_head, hash_entry) { | |
4b32d0a4 | 723 | if (class->key == key) { |
0119fee4 PZ |
724 | /* |
725 | * Huh! same key, different name? Did someone trample | |
726 | * on some memory? We're most confused. | |
727 | */ | |
4b32d0a4 | 728 | WARN_ON_ONCE(class->name != lock->name); |
8e18257d | 729 | return class; |
4b32d0a4 PZ |
730 | } |
731 | } | |
fbb9ce95 | 732 | |
8e18257d | 733 | return NULL; |
fbb9ce95 IM |
734 | } |
735 | ||
736 | /* | |
8e18257d PZ |
737 | * Register a lock's class in the hash-table, if the class is not present |
738 | * yet. Otherwise we look it up. We cache the result in the lock object | |
739 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 740 | */ |
8e18257d PZ |
741 | static inline struct lock_class * |
742 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 743 | { |
8e18257d PZ |
744 | struct lockdep_subclass_key *key; |
745 | struct list_head *hash_head; | |
746 | struct lock_class *class; | |
35a9393c PZ |
747 | |
748 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); | |
8e18257d PZ |
749 | |
750 | class = look_up_lock_class(lock, subclass); | |
751 | if (likely(class)) | |
87cdee71 | 752 | goto out_set_class_cache; |
8e18257d PZ |
753 | |
754 | /* | |
755 | * Debug-check: all keys must be persistent! | |
756 | */ | |
757 | if (!static_obj(lock->key)) { | |
758 | debug_locks_off(); | |
759 | printk("INFO: trying to register non-static key.\n"); | |
760 | printk("the code is fine but needs lockdep annotation.\n"); | |
761 | printk("turning off the locking correctness validator.\n"); | |
762 | dump_stack(); | |
763 | ||
764 | return NULL; | |
765 | } | |
766 | ||
767 | key = lock->key->subkeys + subclass; | |
768 | hash_head = classhashentry(key); | |
769 | ||
8e18257d | 770 | if (!graph_lock()) { |
8e18257d PZ |
771 | return NULL; |
772 | } | |
773 | /* | |
774 | * We have to do the hash-walk again, to avoid races | |
775 | * with another CPU: | |
776 | */ | |
35a9393c | 777 | list_for_each_entry_rcu(class, hash_head, hash_entry) { |
8e18257d PZ |
778 | if (class->key == key) |
779 | goto out_unlock_set; | |
35a9393c PZ |
780 | } |
781 | ||
8e18257d PZ |
782 | /* |
783 | * Allocate a new key from the static array, and add it to | |
784 | * the hash: | |
785 | */ | |
786 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
787 | if (!debug_locks_off_graph_unlock()) { | |
8e18257d PZ |
788 | return NULL; |
789 | } | |
8e18257d | 790 | |
2c522836 | 791 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
eedeeabd | 792 | dump_stack(); |
8e18257d PZ |
793 | return NULL; |
794 | } | |
795 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 796 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
797 | class->key = key; |
798 | class->name = lock->name; | |
799 | class->subclass = subclass; | |
800 | INIT_LIST_HEAD(&class->lock_entry); | |
801 | INIT_LIST_HEAD(&class->locks_before); | |
802 | INIT_LIST_HEAD(&class->locks_after); | |
803 | class->name_version = count_matching_names(class); | |
804 | /* | |
805 | * We use RCU's safe list-add method to make | |
806 | * parallel walking of the hash-list safe: | |
807 | */ | |
808 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
809 | /* |
810 | * Add it to the global list of classes: | |
811 | */ | |
812 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
813 | |
814 | if (verbose(class)) { | |
815 | graph_unlock(); | |
8e18257d PZ |
816 | |
817 | printk("\nnew class %p: %s", class->key, class->name); | |
818 | if (class->name_version > 1) | |
819 | printk("#%d", class->name_version); | |
820 | printk("\n"); | |
821 | dump_stack(); | |
822 | ||
8e18257d | 823 | if (!graph_lock()) { |
8e18257d PZ |
824 | return NULL; |
825 | } | |
826 | } | |
827 | out_unlock_set: | |
828 | graph_unlock(); | |
8e18257d | 829 | |
87cdee71 | 830 | out_set_class_cache: |
8e18257d | 831 | if (!subclass || force) |
62016250 HM |
832 | lock->class_cache[0] = class; |
833 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
834 | lock->class_cache[subclass] = class; | |
8e18257d | 835 | |
0119fee4 PZ |
836 | /* |
837 | * Hash collision, did we smoke some? We found a class with a matching | |
838 | * hash but the subclass -- which is hashed in -- didn't match. | |
839 | */ | |
8e18257d PZ |
840 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
841 | return NULL; | |
842 | ||
843 | return class; | |
844 | } | |
845 | ||
846 | #ifdef CONFIG_PROVE_LOCKING | |
847 | /* | |
848 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
849 | * with NULL on failure) | |
850 | */ | |
851 | static struct lock_list *alloc_list_entry(void) | |
852 | { | |
853 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
854 | if (!debug_locks_off_graph_unlock()) | |
855 | return NULL; | |
856 | ||
2c522836 | 857 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
eedeeabd | 858 | dump_stack(); |
8e18257d PZ |
859 | return NULL; |
860 | } | |
861 | return list_entries + nr_list_entries++; | |
862 | } | |
863 | ||
864 | /* | |
865 | * Add a new dependency to the head of the list: | |
866 | */ | |
867 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
4726f2a6 YZ |
868 | struct list_head *head, unsigned long ip, |
869 | int distance, struct stack_trace *trace) | |
8e18257d PZ |
870 | { |
871 | struct lock_list *entry; | |
872 | /* | |
873 | * Lock not present yet - get a new dependency struct and | |
874 | * add it to the list: | |
875 | */ | |
876 | entry = alloc_list_entry(); | |
877 | if (!entry) | |
878 | return 0; | |
879 | ||
74870172 ZY |
880 | entry->class = this; |
881 | entry->distance = distance; | |
4726f2a6 | 882 | entry->trace = *trace; |
8e18257d | 883 | /* |
35a9393c PZ |
884 | * Both allocation and removal are done under the graph lock; but |
885 | * iteration is under RCU-sched; see look_up_lock_class() and | |
886 | * lockdep_free_key_range(). | |
8e18257d PZ |
887 | */ |
888 | list_add_tail_rcu(&entry->entry, head); | |
889 | ||
890 | return 1; | |
891 | } | |
892 | ||
98c33edd PZ |
893 | /* |
894 | * For good efficiency of modular, we use power of 2 | |
895 | */ | |
af012961 PZ |
896 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
897 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
898 | ||
98c33edd PZ |
899 | /* |
900 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
901 | * breadth-first search(BFS)algorithem, by which we can build |
902 | * the shortest path from the next lock to be acquired to the | |
903 | * previous held lock if there is a circular between them. | |
98c33edd | 904 | */ |
af012961 PZ |
905 | struct circular_queue { |
906 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
907 | unsigned int front, rear; | |
908 | }; | |
909 | ||
910 | static struct circular_queue lock_cq; | |
af012961 | 911 | |
12f3dfd0 | 912 | unsigned int max_bfs_queue_depth; |
af012961 | 913 | |
e351b660 ML |
914 | static unsigned int lockdep_dependency_gen_id; |
915 | ||
af012961 PZ |
916 | static inline void __cq_init(struct circular_queue *cq) |
917 | { | |
918 | cq->front = cq->rear = 0; | |
e351b660 | 919 | lockdep_dependency_gen_id++; |
af012961 PZ |
920 | } |
921 | ||
922 | static inline int __cq_empty(struct circular_queue *cq) | |
923 | { | |
924 | return (cq->front == cq->rear); | |
925 | } | |
926 | ||
927 | static inline int __cq_full(struct circular_queue *cq) | |
928 | { | |
929 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
930 | } | |
931 | ||
932 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
933 | { | |
934 | if (__cq_full(cq)) | |
935 | return -1; | |
936 | ||
937 | cq->element[cq->rear] = elem; | |
938 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
939 | return 0; | |
940 | } | |
941 | ||
942 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
943 | { | |
944 | if (__cq_empty(cq)) | |
945 | return -1; | |
946 | ||
947 | *elem = cq->element[cq->front]; | |
948 | cq->front = (cq->front + 1) & CQ_MASK; | |
949 | return 0; | |
950 | } | |
951 | ||
952 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
953 | { | |
954 | return (cq->rear - cq->front) & CQ_MASK; | |
955 | } | |
956 | ||
957 | static inline void mark_lock_accessed(struct lock_list *lock, | |
958 | struct lock_list *parent) | |
959 | { | |
960 | unsigned long nr; | |
98c33edd | 961 | |
af012961 | 962 | nr = lock - list_entries; |
0119fee4 | 963 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
af012961 | 964 | lock->parent = parent; |
e351b660 | 965 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
966 | } |
967 | ||
968 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
969 | { | |
970 | unsigned long nr; | |
98c33edd | 971 | |
af012961 | 972 | nr = lock - list_entries; |
0119fee4 | 973 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
e351b660 | 974 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
975 | } |
976 | ||
977 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
978 | { | |
979 | return child->parent; | |
980 | } | |
981 | ||
982 | static inline int get_lock_depth(struct lock_list *child) | |
983 | { | |
984 | int depth = 0; | |
985 | struct lock_list *parent; | |
986 | ||
987 | while ((parent = get_lock_parent(child))) { | |
988 | child = parent; | |
989 | depth++; | |
990 | } | |
991 | return depth; | |
992 | } | |
993 | ||
9e2d551e | 994 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
995 | void *data, |
996 | int (*match)(struct lock_list *entry, void *data), | |
997 | struct lock_list **target_entry, | |
998 | int forward) | |
c94aa5ca ML |
999 | { |
1000 | struct lock_list *entry; | |
d588e461 | 1001 | struct list_head *head; |
c94aa5ca ML |
1002 | struct circular_queue *cq = &lock_cq; |
1003 | int ret = 1; | |
1004 | ||
9e2d551e | 1005 | if (match(source_entry, data)) { |
c94aa5ca ML |
1006 | *target_entry = source_entry; |
1007 | ret = 0; | |
1008 | goto exit; | |
1009 | } | |
1010 | ||
d588e461 ML |
1011 | if (forward) |
1012 | head = &source_entry->class->locks_after; | |
1013 | else | |
1014 | head = &source_entry->class->locks_before; | |
1015 | ||
1016 | if (list_empty(head)) | |
1017 | goto exit; | |
1018 | ||
1019 | __cq_init(cq); | |
c94aa5ca ML |
1020 | __cq_enqueue(cq, (unsigned long)source_entry); |
1021 | ||
1022 | while (!__cq_empty(cq)) { | |
1023 | struct lock_list *lock; | |
c94aa5ca ML |
1024 | |
1025 | __cq_dequeue(cq, (unsigned long *)&lock); | |
1026 | ||
1027 | if (!lock->class) { | |
1028 | ret = -2; | |
1029 | goto exit; | |
1030 | } | |
1031 | ||
1032 | if (forward) | |
1033 | head = &lock->class->locks_after; | |
1034 | else | |
1035 | head = &lock->class->locks_before; | |
1036 | ||
35a9393c PZ |
1037 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
1038 | ||
1039 | list_for_each_entry_rcu(entry, head, entry) { | |
c94aa5ca | 1040 | if (!lock_accessed(entry)) { |
12f3dfd0 | 1041 | unsigned int cq_depth; |
c94aa5ca | 1042 | mark_lock_accessed(entry, lock); |
9e2d551e | 1043 | if (match(entry, data)) { |
c94aa5ca ML |
1044 | *target_entry = entry; |
1045 | ret = 0; | |
1046 | goto exit; | |
1047 | } | |
1048 | ||
1049 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1050 | ret = -1; | |
1051 | goto exit; | |
1052 | } | |
12f3dfd0 ML |
1053 | cq_depth = __cq_get_elem_count(cq); |
1054 | if (max_bfs_queue_depth < cq_depth) | |
1055 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1056 | } |
1057 | } | |
1058 | } | |
1059 | exit: | |
1060 | return ret; | |
1061 | } | |
1062 | ||
d7aaba14 | 1063 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1064 | void *data, |
1065 | int (*match)(struct lock_list *entry, void *data), | |
1066 | struct lock_list **target_entry) | |
c94aa5ca | 1067 | { |
9e2d551e | 1068 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1069 | |
1070 | } | |
1071 | ||
d7aaba14 | 1072 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1073 | void *data, |
1074 | int (*match)(struct lock_list *entry, void *data), | |
1075 | struct lock_list **target_entry) | |
c94aa5ca | 1076 | { |
9e2d551e | 1077 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1078 | |
1079 | } | |
1080 | ||
8e18257d PZ |
1081 | /* |
1082 | * Recursive, forwards-direction lock-dependency checking, used for | |
1083 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1084 | * checking. | |
8e18257d | 1085 | */ |
8e18257d PZ |
1086 | |
1087 | /* | |
1088 | * Print a dependency chain entry (this is only done when a deadlock | |
1089 | * has been detected): | |
1090 | */ | |
1091 | static noinline int | |
24208ca7 | 1092 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1093 | { |
1094 | if (debug_locks_silent) | |
1095 | return 0; | |
1096 | printk("\n-> #%u", depth); | |
1097 | print_lock_name(target->class); | |
1098 | printk(":\n"); | |
1099 | print_stack_trace(&target->trace, 6); | |
1100 | ||
1101 | return 0; | |
1102 | } | |
1103 | ||
f4185812 SR |
1104 | static void |
1105 | print_circular_lock_scenario(struct held_lock *src, | |
1106 | struct held_lock *tgt, | |
1107 | struct lock_list *prt) | |
1108 | { | |
1109 | struct lock_class *source = hlock_class(src); | |
1110 | struct lock_class *target = hlock_class(tgt); | |
1111 | struct lock_class *parent = prt->class; | |
1112 | ||
1113 | /* | |
1114 | * A direct locking problem where unsafe_class lock is taken | |
1115 | * directly by safe_class lock, then all we need to show | |
1116 | * is the deadlock scenario, as it is obvious that the | |
1117 | * unsafe lock is taken under the safe lock. | |
1118 | * | |
1119 | * But if there is a chain instead, where the safe lock takes | |
1120 | * an intermediate lock (middle_class) where this lock is | |
1121 | * not the same as the safe lock, then the lock chain is | |
1122 | * used to describe the problem. Otherwise we would need | |
1123 | * to show a different CPU case for each link in the chain | |
1124 | * from the safe_class lock to the unsafe_class lock. | |
1125 | */ | |
1126 | if (parent != source) { | |
1127 | printk("Chain exists of:\n "); | |
1128 | __print_lock_name(source); | |
1129 | printk(" --> "); | |
1130 | __print_lock_name(parent); | |
1131 | printk(" --> "); | |
1132 | __print_lock_name(target); | |
1133 | printk("\n\n"); | |
1134 | } | |
1135 | ||
1136 | printk(" Possible unsafe locking scenario:\n\n"); | |
1137 | printk(" CPU0 CPU1\n"); | |
1138 | printk(" ---- ----\n"); | |
1139 | printk(" lock("); | |
1140 | __print_lock_name(target); | |
1141 | printk(");\n"); | |
1142 | printk(" lock("); | |
1143 | __print_lock_name(parent); | |
1144 | printk(");\n"); | |
1145 | printk(" lock("); | |
1146 | __print_lock_name(target); | |
1147 | printk(");\n"); | |
1148 | printk(" lock("); | |
1149 | __print_lock_name(source); | |
1150 | printk(");\n"); | |
1151 | printk("\n *** DEADLOCK ***\n\n"); | |
1152 | } | |
1153 | ||
8e18257d PZ |
1154 | /* |
1155 | * When a circular dependency is detected, print the | |
1156 | * header first: | |
1157 | */ | |
1158 | static noinline int | |
db0002a3 ML |
1159 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1160 | struct held_lock *check_src, | |
1161 | struct held_lock *check_tgt) | |
8e18257d PZ |
1162 | { |
1163 | struct task_struct *curr = current; | |
1164 | ||
c94aa5ca | 1165 | if (debug_locks_silent) |
8e18257d PZ |
1166 | return 0; |
1167 | ||
b3fbab05 PM |
1168 | printk("\n"); |
1169 | printk("======================================================\n"); | |
1170 | printk("[ INFO: possible circular locking dependency detected ]\n"); | |
fbdc4b9a | 1171 | print_kernel_ident(); |
b3fbab05 | 1172 | printk("-------------------------------------------------------\n"); |
8e18257d | 1173 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1174 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1175 | print_lock(check_src); |
8e18257d | 1176 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1177 | print_lock(check_tgt); |
8e18257d PZ |
1178 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1179 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1180 | ||
1181 | print_circular_bug_entry(entry, depth); | |
1182 | ||
1183 | return 0; | |
1184 | } | |
1185 | ||
9e2d551e ML |
1186 | static inline int class_equal(struct lock_list *entry, void *data) |
1187 | { | |
1188 | return entry->class == data; | |
1189 | } | |
1190 | ||
db0002a3 ML |
1191 | static noinline int print_circular_bug(struct lock_list *this, |
1192 | struct lock_list *target, | |
1193 | struct held_lock *check_src, | |
1194 | struct held_lock *check_tgt) | |
8e18257d PZ |
1195 | { |
1196 | struct task_struct *curr = current; | |
c94aa5ca | 1197 | struct lock_list *parent; |
f4185812 | 1198 | struct lock_list *first_parent; |
24208ca7 | 1199 | int depth; |
8e18257d | 1200 | |
c94aa5ca | 1201 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1202 | return 0; |
1203 | ||
db0002a3 | 1204 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1205 | return 0; |
1206 | ||
c94aa5ca ML |
1207 | depth = get_lock_depth(target); |
1208 | ||
db0002a3 | 1209 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1210 | |
1211 | parent = get_lock_parent(target); | |
f4185812 | 1212 | first_parent = parent; |
c94aa5ca ML |
1213 | |
1214 | while (parent) { | |
1215 | print_circular_bug_entry(parent, --depth); | |
1216 | parent = get_lock_parent(parent); | |
1217 | } | |
8e18257d PZ |
1218 | |
1219 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1220 | print_circular_lock_scenario(check_src, check_tgt, |
1221 | first_parent); | |
1222 | ||
8e18257d PZ |
1223 | lockdep_print_held_locks(curr); |
1224 | ||
1225 | printk("\nstack backtrace:\n"); | |
1226 | dump_stack(); | |
1227 | ||
1228 | return 0; | |
1229 | } | |
1230 | ||
db0002a3 ML |
1231 | static noinline int print_bfs_bug(int ret) |
1232 | { | |
1233 | if (!debug_locks_off_graph_unlock()) | |
1234 | return 0; | |
1235 | ||
0119fee4 PZ |
1236 | /* |
1237 | * Breadth-first-search failed, graph got corrupted? | |
1238 | */ | |
db0002a3 ML |
1239 | WARN(1, "lockdep bfs error:%d\n", ret); |
1240 | ||
1241 | return 0; | |
1242 | } | |
1243 | ||
ef681026 | 1244 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1245 | { |
ef681026 ML |
1246 | (*(unsigned long *)data)++; |
1247 | return 0; | |
1248 | } | |
419ca3f1 | 1249 | |
5216d530 | 1250 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
ef681026 ML |
1251 | { |
1252 | unsigned long count = 0; | |
1253 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1254 | |
ef681026 | 1255 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1256 | |
ef681026 | 1257 | return count; |
419ca3f1 | 1258 | } |
419ca3f1 DM |
1259 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1260 | { | |
1261 | unsigned long ret, flags; | |
ef681026 ML |
1262 | struct lock_list this; |
1263 | ||
1264 | this.parent = NULL; | |
1265 | this.class = class; | |
419ca3f1 DM |
1266 | |
1267 | local_irq_save(flags); | |
0199c4e6 | 1268 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1269 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1270 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1271 | local_irq_restore(flags); |
1272 | ||
1273 | return ret; | |
1274 | } | |
1275 | ||
5216d530 | 1276 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1277 | { |
ef681026 ML |
1278 | unsigned long count = 0; |
1279 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1280 | |
ef681026 | 1281 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1282 | |
ef681026 | 1283 | return count; |
419ca3f1 DM |
1284 | } |
1285 | ||
1286 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1287 | { | |
1288 | unsigned long ret, flags; | |
ef681026 ML |
1289 | struct lock_list this; |
1290 | ||
1291 | this.parent = NULL; | |
1292 | this.class = class; | |
419ca3f1 DM |
1293 | |
1294 | local_irq_save(flags); | |
0199c4e6 | 1295 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1296 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1297 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1298 | local_irq_restore(flags); |
1299 | ||
1300 | return ret; | |
1301 | } | |
1302 | ||
8e18257d PZ |
1303 | /* |
1304 | * Prove that the dependency graph starting at <entry> can not | |
1305 | * lead to <target>. Print an error and return 0 if it does. | |
1306 | */ | |
1307 | static noinline int | |
db0002a3 ML |
1308 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1309 | struct lock_list **target_entry) | |
8e18257d | 1310 | { |
db0002a3 | 1311 | int result; |
8e18257d | 1312 | |
bd6d29c2 | 1313 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1314 | |
d7aaba14 | 1315 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1316 | |
db0002a3 ML |
1317 | return result; |
1318 | } | |
c94aa5ca | 1319 | |
81d68a96 | 1320 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1321 | /* |
1322 | * Forwards and backwards subgraph searching, for the purposes of | |
1323 | * proving that two subgraphs can be connected by a new dependency | |
1324 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1325 | */ | |
fbb9ce95 | 1326 | |
d7aaba14 ML |
1327 | static inline int usage_match(struct lock_list *entry, void *bit) |
1328 | { | |
1329 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1330 | } | |
1331 | ||
1332 | ||
1333 | ||
fbb9ce95 IM |
1334 | /* |
1335 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1336 | * at @root->class that matches @bit. |
fbb9ce95 | 1337 | * |
d7aaba14 ML |
1338 | * Return 0 if such a node exists in the subgraph, and put that node |
1339 | * into *@target_entry. | |
fbb9ce95 | 1340 | * |
d7aaba14 ML |
1341 | * Return 1 otherwise and keep *@target_entry unchanged. |
1342 | * Return <0 on error. | |
fbb9ce95 | 1343 | */ |
d7aaba14 ML |
1344 | static int |
1345 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1346 | struct lock_list **target_entry) | |
fbb9ce95 | 1347 | { |
d7aaba14 | 1348 | int result; |
fbb9ce95 | 1349 | |
bd6d29c2 | 1350 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1351 | |
d7aaba14 ML |
1352 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1353 | ||
1354 | return result; | |
fbb9ce95 IM |
1355 | } |
1356 | ||
1357 | /* | |
1358 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1359 | * at @root->class that matches @bit. |
fbb9ce95 | 1360 | * |
d7aaba14 ML |
1361 | * Return 0 if such a node exists in the subgraph, and put that node |
1362 | * into *@target_entry. | |
fbb9ce95 | 1363 | * |
d7aaba14 ML |
1364 | * Return 1 otherwise and keep *@target_entry unchanged. |
1365 | * Return <0 on error. | |
fbb9ce95 | 1366 | */ |
d7aaba14 ML |
1367 | static int |
1368 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1369 | struct lock_list **target_entry) | |
fbb9ce95 | 1370 | { |
d7aaba14 | 1371 | int result; |
fbb9ce95 | 1372 | |
bd6d29c2 | 1373 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1374 | |
d7aaba14 | 1375 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1376 | |
d7aaba14 | 1377 | return result; |
fbb9ce95 IM |
1378 | } |
1379 | ||
af012961 PZ |
1380 | static void print_lock_class_header(struct lock_class *class, int depth) |
1381 | { | |
1382 | int bit; | |
1383 | ||
1384 | printk("%*s->", depth, ""); | |
1385 | print_lock_name(class); | |
1386 | printk(" ops: %lu", class->ops); | |
1387 | printk(" {\n"); | |
1388 | ||
1389 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1390 | if (class->usage_mask & (1 << bit)) { | |
1391 | int len = depth; | |
1392 | ||
1393 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1394 | len += printk(" at:\n"); | |
1395 | print_stack_trace(class->usage_traces + bit, len); | |
1396 | } | |
1397 | } | |
1398 | printk("%*s }\n", depth, ""); | |
1399 | ||
1400 | printk("%*s ... key at: ",depth,""); | |
1401 | print_ip_sym((unsigned long)class->key); | |
1402 | } | |
1403 | ||
1404 | /* | |
1405 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1406 | */ | |
1407 | static void __used | |
1408 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1409 | struct lock_list *root) | |
1410 | { | |
1411 | struct lock_list *entry = leaf; | |
1412 | int depth; | |
1413 | ||
1414 | /*compute depth from generated tree by BFS*/ | |
1415 | depth = get_lock_depth(leaf); | |
1416 | ||
1417 | do { | |
1418 | print_lock_class_header(entry->class, depth); | |
1419 | printk("%*s ... acquired at:\n", depth, ""); | |
1420 | print_stack_trace(&entry->trace, 2); | |
1421 | printk("\n"); | |
1422 | ||
1423 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1424 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1425 | break; |
1426 | } | |
1427 | ||
1428 | entry = get_lock_parent(entry); | |
1429 | depth--; | |
1430 | } while (entry && (depth >= 0)); | |
1431 | ||
1432 | return; | |
1433 | } | |
d7aaba14 | 1434 | |
3003eba3 SR |
1435 | static void |
1436 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1437 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1438 | struct lock_class *prev_class, |
1439 | struct lock_class *next_class) | |
3003eba3 SR |
1440 | { |
1441 | struct lock_class *safe_class = safe_entry->class; | |
1442 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1443 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1444 | |
1445 | if (middle_class == safe_class) | |
dad3d743 | 1446 | middle_class = next_class; |
3003eba3 SR |
1447 | |
1448 | /* | |
1449 | * A direct locking problem where unsafe_class lock is taken | |
1450 | * directly by safe_class lock, then all we need to show | |
1451 | * is the deadlock scenario, as it is obvious that the | |
1452 | * unsafe lock is taken under the safe lock. | |
1453 | * | |
1454 | * But if there is a chain instead, where the safe lock takes | |
1455 | * an intermediate lock (middle_class) where this lock is | |
1456 | * not the same as the safe lock, then the lock chain is | |
1457 | * used to describe the problem. Otherwise we would need | |
1458 | * to show a different CPU case for each link in the chain | |
1459 | * from the safe_class lock to the unsafe_class lock. | |
1460 | */ | |
1461 | if (middle_class != unsafe_class) { | |
1462 | printk("Chain exists of:\n "); | |
1463 | __print_lock_name(safe_class); | |
1464 | printk(" --> "); | |
1465 | __print_lock_name(middle_class); | |
1466 | printk(" --> "); | |
1467 | __print_lock_name(unsafe_class); | |
1468 | printk("\n\n"); | |
1469 | } | |
1470 | ||
1471 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1472 | printk(" CPU0 CPU1\n"); | |
1473 | printk(" ---- ----\n"); | |
1474 | printk(" lock("); | |
1475 | __print_lock_name(unsafe_class); | |
1476 | printk(");\n"); | |
1477 | printk(" local_irq_disable();\n"); | |
1478 | printk(" lock("); | |
1479 | __print_lock_name(safe_class); | |
1480 | printk(");\n"); | |
1481 | printk(" lock("); | |
1482 | __print_lock_name(middle_class); | |
1483 | printk(");\n"); | |
1484 | printk(" <Interrupt>\n"); | |
1485 | printk(" lock("); | |
1486 | __print_lock_name(safe_class); | |
1487 | printk(");\n"); | |
1488 | printk("\n *** DEADLOCK ***\n\n"); | |
1489 | } | |
1490 | ||
fbb9ce95 IM |
1491 | static int |
1492 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1493 | struct lock_list *prev_root, |
1494 | struct lock_list *next_root, | |
1495 | struct lock_list *backwards_entry, | |
1496 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1497 | struct held_lock *prev, |
1498 | struct held_lock *next, | |
1499 | enum lock_usage_bit bit1, | |
1500 | enum lock_usage_bit bit2, | |
1501 | const char *irqclass) | |
1502 | { | |
74c383f1 | 1503 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1504 | return 0; |
1505 | ||
b3fbab05 PM |
1506 | printk("\n"); |
1507 | printk("======================================================\n"); | |
1508 | printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
fbb9ce95 | 1509 | irqclass, irqclass); |
fbdc4b9a | 1510 | print_kernel_ident(); |
b3fbab05 | 1511 | printk("------------------------------------------------------\n"); |
fbb9ce95 | 1512 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1513 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1514 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1515 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1516 | curr->hardirqs_enabled, | |
1517 | curr->softirqs_enabled); | |
1518 | print_lock(next); | |
1519 | ||
1520 | printk("\nand this task is already holding:\n"); | |
1521 | print_lock(prev); | |
1522 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1523 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1524 | printk(" ->"); |
f82b217e | 1525 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1526 | printk("\n"); |
1527 | ||
1528 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1529 | irqclass); | |
24208ca7 | 1530 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1531 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1532 | ||
24208ca7 | 1533 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1534 | |
1535 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1536 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1537 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1538 | printk("..."); | |
1539 | ||
24208ca7 | 1540 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1541 | |
1542 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1543 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1544 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1545 | |
fbb9ce95 IM |
1546 | lockdep_print_held_locks(curr); |
1547 | ||
24208ca7 ML |
1548 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1549 | printk(" and the holding lock:\n"); | |
1550 | if (!save_trace(&prev_root->trace)) | |
1551 | return 0; | |
1552 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1553 | |
24208ca7 ML |
1554 | printk("\nthe dependencies between the lock to be acquired"); |
1555 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1556 | if (!save_trace(&next_root->trace)) | |
1557 | return 0; | |
1558 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1559 | |
1560 | printk("\nstack backtrace:\n"); | |
1561 | dump_stack(); | |
1562 | ||
1563 | return 0; | |
1564 | } | |
1565 | ||
1566 | static int | |
1567 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1568 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1569 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1570 | { | |
1571 | int ret; | |
24208ca7 | 1572 | struct lock_list this, that; |
d7aaba14 | 1573 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1574 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1575 | |
1576 | this.parent = NULL; | |
1577 | ||
1578 | this.class = hlock_class(prev); | |
1579 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1580 | if (ret < 0) |
1581 | return print_bfs_bug(ret); | |
1582 | if (ret == 1) | |
1583 | return ret; | |
d7aaba14 | 1584 | |
24208ca7 ML |
1585 | that.parent = NULL; |
1586 | that.class = hlock_class(next); | |
1587 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1588 | if (ret < 0) |
1589 | return print_bfs_bug(ret); | |
1590 | if (ret == 1) | |
1591 | return ret; | |
fbb9ce95 | 1592 | |
24208ca7 ML |
1593 | return print_bad_irq_dependency(curr, &this, &that, |
1594 | target_entry, target_entry1, | |
1595 | prev, next, | |
fbb9ce95 IM |
1596 | bit_backwards, bit_forwards, irqclass); |
1597 | } | |
1598 | ||
4f367d8a PZ |
1599 | static const char *state_names[] = { |
1600 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1601 | __stringify(__STATE), |
4f367d8a PZ |
1602 | #include "lockdep_states.h" |
1603 | #undef LOCKDEP_STATE | |
1604 | }; | |
1605 | ||
1606 | static const char *state_rnames[] = { | |
1607 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1608 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1609 | #include "lockdep_states.h" |
1610 | #undef LOCKDEP_STATE | |
1611 | }; | |
1612 | ||
1613 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1614 | { |
4f367d8a PZ |
1615 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1616 | } | |
8e18257d | 1617 | |
4f367d8a PZ |
1618 | static int exclusive_bit(int new_bit) |
1619 | { | |
8e18257d | 1620 | /* |
4f367d8a PZ |
1621 | * USED_IN |
1622 | * USED_IN_READ | |
1623 | * ENABLED | |
1624 | * ENABLED_READ | |
1625 | * | |
1626 | * bit 0 - write/read | |
1627 | * bit 1 - used_in/enabled | |
1628 | * bit 2+ state | |
8e18257d | 1629 | */ |
4f367d8a PZ |
1630 | |
1631 | int state = new_bit & ~3; | |
1632 | int dir = new_bit & 2; | |
8e18257d PZ |
1633 | |
1634 | /* | |
4f367d8a | 1635 | * keep state, bit flip the direction and strip read. |
8e18257d | 1636 | */ |
4f367d8a PZ |
1637 | return state | (dir ^ 2); |
1638 | } | |
1639 | ||
1640 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1641 | struct held_lock *next, enum lock_usage_bit bit) | |
1642 | { | |
8e18257d | 1643 | /* |
4f367d8a PZ |
1644 | * Prove that the new dependency does not connect a hardirq-safe |
1645 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1646 | * the backwards-subgraph starting at <prev>, and the |
1647 | * forwards-subgraph starting at <next>: | |
1648 | */ | |
4f367d8a PZ |
1649 | if (!check_usage(curr, prev, next, bit, |
1650 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1651 | return 0; |
1652 | ||
4f367d8a PZ |
1653 | bit++; /* _READ */ |
1654 | ||
cf40bd16 | 1655 | /* |
4f367d8a PZ |
1656 | * Prove that the new dependency does not connect a hardirq-safe-read |
1657 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1658 | * the backwards-subgraph starting at <prev>, and the |
1659 | * forwards-subgraph starting at <next>: | |
1660 | */ | |
4f367d8a PZ |
1661 | if (!check_usage(curr, prev, next, bit, |
1662 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1663 | return 0; |
1664 | ||
4f367d8a PZ |
1665 | return 1; |
1666 | } | |
1667 | ||
1668 | static int | |
1669 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1670 | struct held_lock *next) | |
1671 | { | |
1672 | #define LOCKDEP_STATE(__STATE) \ | |
1673 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1674 | return 0; |
4f367d8a PZ |
1675 | #include "lockdep_states.h" |
1676 | #undef LOCKDEP_STATE | |
cf40bd16 | 1677 | |
8e18257d PZ |
1678 | return 1; |
1679 | } | |
1680 | ||
1681 | static void inc_chains(void) | |
1682 | { | |
1683 | if (current->hardirq_context) | |
1684 | nr_hardirq_chains++; | |
1685 | else { | |
1686 | if (current->softirq_context) | |
1687 | nr_softirq_chains++; | |
1688 | else | |
1689 | nr_process_chains++; | |
1690 | } | |
1691 | } | |
1692 | ||
1693 | #else | |
1694 | ||
1695 | static inline int | |
1696 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1697 | struct held_lock *next) | |
1698 | { | |
1699 | return 1; | |
1700 | } | |
1701 | ||
1702 | static inline void inc_chains(void) | |
1703 | { | |
1704 | nr_process_chains++; | |
1705 | } | |
1706 | ||
fbb9ce95 IM |
1707 | #endif |
1708 | ||
48702ecf SR |
1709 | static void |
1710 | print_deadlock_scenario(struct held_lock *nxt, | |
1711 | struct held_lock *prv) | |
1712 | { | |
1713 | struct lock_class *next = hlock_class(nxt); | |
1714 | struct lock_class *prev = hlock_class(prv); | |
1715 | ||
1716 | printk(" Possible unsafe locking scenario:\n\n"); | |
1717 | printk(" CPU0\n"); | |
1718 | printk(" ----\n"); | |
1719 | printk(" lock("); | |
1720 | __print_lock_name(prev); | |
1721 | printk(");\n"); | |
1722 | printk(" lock("); | |
1723 | __print_lock_name(next); | |
1724 | printk(");\n"); | |
1725 | printk("\n *** DEADLOCK ***\n\n"); | |
1726 | printk(" May be due to missing lock nesting notation\n\n"); | |
1727 | } | |
1728 | ||
fbb9ce95 IM |
1729 | static int |
1730 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1731 | struct held_lock *next) | |
1732 | { | |
74c383f1 | 1733 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1734 | return 0; |
1735 | ||
b3fbab05 PM |
1736 | printk("\n"); |
1737 | printk("=============================================\n"); | |
1738 | printk("[ INFO: possible recursive locking detected ]\n"); | |
fbdc4b9a | 1739 | print_kernel_ident(); |
b3fbab05 | 1740 | printk("---------------------------------------------\n"); |
fbb9ce95 | 1741 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1742 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1743 | print_lock(next); |
1744 | printk("\nbut task is already holding lock:\n"); | |
1745 | print_lock(prev); | |
1746 | ||
1747 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1748 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1749 | lockdep_print_held_locks(curr); |
1750 | ||
1751 | printk("\nstack backtrace:\n"); | |
1752 | dump_stack(); | |
1753 | ||
1754 | return 0; | |
1755 | } | |
1756 | ||
1757 | /* | |
1758 | * Check whether we are holding such a class already. | |
1759 | * | |
1760 | * (Note that this has to be done separately, because the graph cannot | |
1761 | * detect such classes of deadlocks.) | |
1762 | * | |
1763 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1764 | */ | |
1765 | static int | |
1766 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1767 | struct lockdep_map *next_instance, int read) | |
1768 | { | |
1769 | struct held_lock *prev; | |
7531e2f3 | 1770 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1771 | int i; |
1772 | ||
1773 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1774 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1775 | |
1776 | if (prev->instance == next->nest_lock) | |
1777 | nest = prev; | |
1778 | ||
f82b217e | 1779 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1780 | continue; |
7531e2f3 | 1781 | |
fbb9ce95 IM |
1782 | /* |
1783 | * Allow read-after-read recursion of the same | |
6c9076ec | 1784 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1785 | */ |
6c9076ec | 1786 | if ((read == 2) && prev->read) |
fbb9ce95 | 1787 | return 2; |
7531e2f3 PZ |
1788 | |
1789 | /* | |
1790 | * We're holding the nest_lock, which serializes this lock's | |
1791 | * nesting behaviour. | |
1792 | */ | |
1793 | if (nest) | |
1794 | return 2; | |
1795 | ||
fbb9ce95 IM |
1796 | return print_deadlock_bug(curr, prev, next); |
1797 | } | |
1798 | return 1; | |
1799 | } | |
1800 | ||
1801 | /* | |
1802 | * There was a chain-cache miss, and we are about to add a new dependency | |
1803 | * to a previous lock. We recursively validate the following rules: | |
1804 | * | |
1805 | * - would the adding of the <prev> -> <next> dependency create a | |
1806 | * circular dependency in the graph? [== circular deadlock] | |
1807 | * | |
1808 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1809 | * (in the full backwards-subgraph starting at <prev>) with any | |
1810 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1811 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1812 | * | |
1813 | * - does the new prev->next dependency connect any softirq-safe lock | |
1814 | * (in the full backwards-subgraph starting at <prev>) with any | |
1815 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1816 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1817 | * | |
1818 | * any of these scenarios could lead to a deadlock. | |
1819 | * | |
1820 | * Then if all the validations pass, we add the forwards and backwards | |
1821 | * dependency. | |
1822 | */ | |
1823 | static int | |
1824 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
4726f2a6 | 1825 | struct held_lock *next, int distance, int trylock_loop) |
fbb9ce95 IM |
1826 | { |
1827 | struct lock_list *entry; | |
1828 | int ret; | |
db0002a3 ML |
1829 | struct lock_list this; |
1830 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1831 | /* |
1832 | * Static variable, serialized by the graph_lock(). | |
1833 | * | |
1834 | * We use this static variable to save the stack trace in case | |
1835 | * we call into this function multiple times due to encountering | |
1836 | * trylocks in the held lock stack. | |
1837 | */ | |
1838 | static struct stack_trace trace; | |
fbb9ce95 IM |
1839 | |
1840 | /* | |
1841 | * Prove that the new <prev> -> <next> dependency would not | |
1842 | * create a circular dependency in the graph. (We do this by | |
1843 | * forward-recursing into the graph starting at <next>, and | |
1844 | * checking whether we can reach <prev>.) | |
1845 | * | |
1846 | * We are using global variables to control the recursion, to | |
1847 | * keep the stackframe size of the recursive functions low: | |
1848 | */ | |
db0002a3 ML |
1849 | this.class = hlock_class(next); |
1850 | this.parent = NULL; | |
1851 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1852 | if (unlikely(!ret)) | |
1853 | return print_circular_bug(&this, target_entry, next, prev); | |
1854 | else if (unlikely(ret < 0)) | |
1855 | return print_bfs_bug(ret); | |
c94aa5ca | 1856 | |
8e18257d | 1857 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1858 | return 0; |
1859 | ||
fbb9ce95 IM |
1860 | /* |
1861 | * For recursive read-locks we do all the dependency checks, | |
1862 | * but we dont store read-triggered dependencies (only | |
1863 | * write-triggered dependencies). This ensures that only the | |
1864 | * write-side dependencies matter, and that if for example a | |
1865 | * write-lock never takes any other locks, then the reads are | |
1866 | * equivalent to a NOP. | |
1867 | */ | |
1868 | if (next->read == 2 || prev->read == 2) | |
1869 | return 1; | |
1870 | /* | |
1871 | * Is the <prev> -> <next> dependency already present? | |
1872 | * | |
1873 | * (this may occur even though this is a new chain: consider | |
1874 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1875 | * chains - the second one will be new, but L1 already has | |
1876 | * L2 added to its dependency list, due to the first chain.) | |
1877 | */ | |
f82b217e DJ |
1878 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1879 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1880 | if (distance == 1) |
1881 | entry->distance = 1; | |
fbb9ce95 | 1882 | return 2; |
068135e6 | 1883 | } |
fbb9ce95 IM |
1884 | } |
1885 | ||
4726f2a6 YZ |
1886 | if (!trylock_loop && !save_trace(&trace)) |
1887 | return 0; | |
1888 | ||
fbb9ce95 IM |
1889 | /* |
1890 | * Ok, all validations passed, add the new lock | |
1891 | * to the previous lock's dependency list: | |
1892 | */ | |
f82b217e DJ |
1893 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1894 | &hlock_class(prev)->locks_after, | |
4726f2a6 | 1895 | next->acquire_ip, distance, &trace); |
068135e6 | 1896 | |
fbb9ce95 IM |
1897 | if (!ret) |
1898 | return 0; | |
910b1b2e | 1899 | |
f82b217e DJ |
1900 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1901 | &hlock_class(next)->locks_before, | |
4726f2a6 | 1902 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1903 | if (!ret) |
1904 | return 0; | |
fbb9ce95 IM |
1905 | |
1906 | /* | |
8e18257d PZ |
1907 | * Debugging printouts: |
1908 | */ | |
f82b217e | 1909 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1910 | graph_unlock(); |
1911 | printk("\n new dependency: "); | |
f82b217e | 1912 | print_lock_name(hlock_class(prev)); |
8e18257d | 1913 | printk(" => "); |
f82b217e | 1914 | print_lock_name(hlock_class(next)); |
8e18257d | 1915 | printk("\n"); |
fbb9ce95 | 1916 | dump_stack(); |
8e18257d | 1917 | return graph_lock(); |
fbb9ce95 | 1918 | } |
8e18257d PZ |
1919 | return 1; |
1920 | } | |
fbb9ce95 | 1921 | |
8e18257d PZ |
1922 | /* |
1923 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1924 | * The ones that are relevant are (in increasing distance from curr): | |
1925 | * all consecutive trylock entries and the final non-trylock entry - or | |
1926 | * the end of this context's lock-chain - whichever comes first. | |
1927 | */ | |
1928 | static int | |
1929 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1930 | { | |
1931 | int depth = curr->lockdep_depth; | |
4726f2a6 | 1932 | int trylock_loop = 0; |
8e18257d | 1933 | struct held_lock *hlock; |
d6d897ce | 1934 | |
fbb9ce95 | 1935 | /* |
8e18257d PZ |
1936 | * Debugging checks. |
1937 | * | |
1938 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1939 | */ |
8e18257d PZ |
1940 | if (!depth) |
1941 | goto out_bug; | |
fbb9ce95 | 1942 | /* |
8e18257d PZ |
1943 | * At least two relevant locks must exist for this |
1944 | * to be a head: | |
fbb9ce95 | 1945 | */ |
8e18257d PZ |
1946 | if (curr->held_locks[depth].irq_context != |
1947 | curr->held_locks[depth-1].irq_context) | |
1948 | goto out_bug; | |
74c383f1 | 1949 | |
8e18257d PZ |
1950 | for (;;) { |
1951 | int distance = curr->lockdep_depth - depth + 1; | |
1b5ff816 | 1952 | hlock = curr->held_locks + depth - 1; |
8e18257d PZ |
1953 | /* |
1954 | * Only non-recursive-read entries get new dependencies | |
1955 | * added: | |
1956 | */ | |
1b5ff816 | 1957 | if (hlock->read != 2 && hlock->check) { |
4726f2a6 YZ |
1958 | if (!check_prev_add(curr, hlock, next, |
1959 | distance, trylock_loop)) | |
8e18257d PZ |
1960 | return 0; |
1961 | /* | |
1962 | * Stop after the first non-trylock entry, | |
1963 | * as non-trylock entries have added their | |
1964 | * own direct dependencies already, so this | |
1965 | * lock is connected to them indirectly: | |
1966 | */ | |
1967 | if (!hlock->trylock) | |
1968 | break; | |
74c383f1 | 1969 | } |
8e18257d PZ |
1970 | depth--; |
1971 | /* | |
1972 | * End of lock-stack? | |
1973 | */ | |
1974 | if (!depth) | |
1975 | break; | |
1976 | /* | |
1977 | * Stop the search if we cross into another context: | |
1978 | */ | |
1979 | if (curr->held_locks[depth].irq_context != | |
1980 | curr->held_locks[depth-1].irq_context) | |
1981 | break; | |
4726f2a6 | 1982 | trylock_loop = 1; |
fbb9ce95 | 1983 | } |
8e18257d PZ |
1984 | return 1; |
1985 | out_bug: | |
1986 | if (!debug_locks_off_graph_unlock()) | |
1987 | return 0; | |
fbb9ce95 | 1988 | |
0119fee4 PZ |
1989 | /* |
1990 | * Clearly we all shouldn't be here, but since we made it we | |
1991 | * can reliable say we messed up our state. See the above two | |
1992 | * gotos for reasons why we could possibly end up here. | |
1993 | */ | |
8e18257d | 1994 | WARN_ON(1); |
fbb9ce95 | 1995 | |
8e18257d | 1996 | return 0; |
fbb9ce95 IM |
1997 | } |
1998 | ||
8e18257d | 1999 | unsigned long nr_lock_chains; |
443cd507 | 2000 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 2001 | int nr_chain_hlocks; |
443cd507 HY |
2002 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
2003 | ||
2004 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
2005 | { | |
2006 | return lock_classes + chain_hlocks[chain->base + i]; | |
2007 | } | |
8e18257d | 2008 | |
fbb9ce95 IM |
2009 | /* |
2010 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
2011 | * add it and return 1 - in this case the new dependency chain is |
2012 | * validated. If the key is already hashed, return 0. | |
2013 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 2014 | */ |
443cd507 HY |
2015 | static inline int lookup_chain_cache(struct task_struct *curr, |
2016 | struct held_lock *hlock, | |
2017 | u64 chain_key) | |
fbb9ce95 | 2018 | { |
f82b217e | 2019 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
2020 | struct list_head *hash_head = chainhashentry(chain_key); |
2021 | struct lock_chain *chain; | |
bfaf4af8 | 2022 | struct held_lock *hlock_curr; |
e0944ee6 | 2023 | int i, j; |
fbb9ce95 | 2024 | |
0119fee4 PZ |
2025 | /* |
2026 | * We might need to take the graph lock, ensure we've got IRQs | |
2027 | * disabled to make this an IRQ-safe lock.. for recursion reasons | |
2028 | * lockdep won't complain about its own locking errors. | |
2029 | */ | |
381a2292 JP |
2030 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2031 | return 0; | |
fbb9ce95 IM |
2032 | /* |
2033 | * We can walk it lock-free, because entries only get added | |
2034 | * to the hash: | |
2035 | */ | |
35a9393c | 2036 | list_for_each_entry_rcu(chain, hash_head, entry) { |
fbb9ce95 IM |
2037 | if (chain->chain_key == chain_key) { |
2038 | cache_hit: | |
bd6d29c2 | 2039 | debug_atomic_inc(chain_lookup_hits); |
81fc685a | 2040 | if (very_verbose(class)) |
755cd900 AM |
2041 | printk("\nhash chain already cached, key: " |
2042 | "%016Lx tail class: [%p] %s\n", | |
2043 | (unsigned long long)chain_key, | |
2044 | class->key, class->name); | |
fbb9ce95 IM |
2045 | return 0; |
2046 | } | |
2047 | } | |
81fc685a | 2048 | if (very_verbose(class)) |
755cd900 AM |
2049 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2050 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2051 | /* |
2052 | * Allocate a new chain entry from the static array, and add | |
2053 | * it to the hash: | |
2054 | */ | |
74c383f1 IM |
2055 | if (!graph_lock()) |
2056 | return 0; | |
fbb9ce95 IM |
2057 | /* |
2058 | * We have to walk the chain again locked - to avoid duplicates: | |
2059 | */ | |
2060 | list_for_each_entry(chain, hash_head, entry) { | |
2061 | if (chain->chain_key == chain_key) { | |
74c383f1 | 2062 | graph_unlock(); |
fbb9ce95 IM |
2063 | goto cache_hit; |
2064 | } | |
2065 | } | |
2066 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2067 | if (!debug_locks_off_graph_unlock()) |
2068 | return 0; | |
2069 | ||
2c522836 | 2070 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
eedeeabd | 2071 | dump_stack(); |
fbb9ce95 IM |
2072 | return 0; |
2073 | } | |
2074 | chain = lock_chains + nr_lock_chains++; | |
2075 | chain->chain_key = chain_key; | |
443cd507 HY |
2076 | chain->irq_context = hlock->irq_context; |
2077 | /* Find the first held_lock of current chain */ | |
443cd507 HY |
2078 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { |
2079 | hlock_curr = curr->held_locks + i; | |
bfaf4af8 | 2080 | if (hlock_curr->irq_context != hlock->irq_context) |
443cd507 | 2081 | break; |
443cd507 HY |
2082 | } |
2083 | i++; | |
2084 | chain->depth = curr->lockdep_depth + 1 - i; | |
e0944ee6 SR |
2085 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2086 | chain->base = nr_chain_hlocks; | |
2087 | nr_chain_hlocks += chain->depth; | |
443cd507 | 2088 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2089 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2090 | chain_hlocks[chain->base + j] = lock_id; |
2091 | } | |
2092 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2093 | } | |
fbb9ce95 | 2094 | list_add_tail_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2095 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2096 | inc_chains(); |
2097 | ||
2098 | return 1; | |
2099 | } | |
2100 | ||
2101 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2102 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2103 | { |
2104 | /* | |
2105 | * Trylock needs to maintain the stack of held locks, but it | |
2106 | * does not add new dependencies, because trylock can be done | |
2107 | * in any order. | |
2108 | * | |
2109 | * We look up the chain_key and do the O(N^2) check and update of | |
2110 | * the dependencies only if this is a new dependency chain. | |
2111 | * (If lookup_chain_cache() returns with 1 it acquires | |
2112 | * graph_lock for us) | |
2113 | */ | |
fb9edbe9 | 2114 | if (!hlock->trylock && hlock->check && |
443cd507 | 2115 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2116 | /* |
2117 | * Check whether last held lock: | |
2118 | * | |
2119 | * - is irq-safe, if this lock is irq-unsafe | |
2120 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2121 | * | |
2122 | * And check whether the new lock's dependency graph | |
2123 | * could lead back to the previous lock. | |
2124 | * | |
2125 | * any of these scenarios could lead to a deadlock. If | |
2126 | * All validations | |
2127 | */ | |
2128 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2129 | ||
2130 | if (!ret) | |
2131 | return 0; | |
2132 | /* | |
2133 | * Mark recursive read, as we jump over it when | |
2134 | * building dependencies (just like we jump over | |
2135 | * trylock entries): | |
2136 | */ | |
2137 | if (ret == 2) | |
2138 | hlock->read = 2; | |
2139 | /* | |
2140 | * Add dependency only if this lock is not the head | |
2141 | * of the chain, and if it's not a secondary read-lock: | |
2142 | */ | |
2143 | if (!chain_head && ret != 2) | |
2144 | if (!check_prevs_add(curr, hlock)) | |
2145 | return 0; | |
2146 | graph_unlock(); | |
2147 | } else | |
2148 | /* after lookup_chain_cache(): */ | |
2149 | if (unlikely(!debug_locks)) | |
2150 | return 0; | |
fbb9ce95 IM |
2151 | |
2152 | return 1; | |
2153 | } | |
8e18257d PZ |
2154 | #else |
2155 | static inline int validate_chain(struct task_struct *curr, | |
2156 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2157 | int chain_head, u64 chain_key) |
8e18257d PZ |
2158 | { |
2159 | return 1; | |
2160 | } | |
ca58abcb | 2161 | #endif |
fbb9ce95 IM |
2162 | |
2163 | /* | |
2164 | * We are building curr_chain_key incrementally, so double-check | |
2165 | * it from scratch, to make sure that it's done correctly: | |
2166 | */ | |
1d09daa5 | 2167 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2168 | { |
2169 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2170 | struct held_lock *hlock, *prev_hlock = NULL; | |
2171 | unsigned int i, id; | |
2172 | u64 chain_key = 0; | |
2173 | ||
2174 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2175 | hlock = curr->held_locks + i; | |
2176 | if (chain_key != hlock->prev_chain_key) { | |
2177 | debug_locks_off(); | |
0119fee4 PZ |
2178 | /* |
2179 | * We got mighty confused, our chain keys don't match | |
2180 | * with what we expect, someone trample on our task state? | |
2181 | */ | |
2df8b1d6 | 2182 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2183 | curr->lockdep_depth, i, |
2184 | (unsigned long long)chain_key, | |
2185 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2186 | return; |
2187 | } | |
f82b217e | 2188 | id = hlock->class_idx - 1; |
0119fee4 PZ |
2189 | /* |
2190 | * Whoops ran out of static storage again? | |
2191 | */ | |
381a2292 JP |
2192 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
2193 | return; | |
2194 | ||
fbb9ce95 IM |
2195 | if (prev_hlock && (prev_hlock->irq_context != |
2196 | hlock->irq_context)) | |
2197 | chain_key = 0; | |
2198 | chain_key = iterate_chain_key(chain_key, id); | |
2199 | prev_hlock = hlock; | |
2200 | } | |
2201 | if (chain_key != curr->curr_chain_key) { | |
2202 | debug_locks_off(); | |
0119fee4 PZ |
2203 | /* |
2204 | * More smoking hash instead of calculating it, damn see these | |
2205 | * numbers float.. I bet that a pink elephant stepped on my memory. | |
2206 | */ | |
2df8b1d6 | 2207 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2208 | curr->lockdep_depth, i, |
2209 | (unsigned long long)chain_key, | |
2210 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2211 | } |
2212 | #endif | |
2213 | } | |
2214 | ||
282b5c2f SR |
2215 | static void |
2216 | print_usage_bug_scenario(struct held_lock *lock) | |
2217 | { | |
2218 | struct lock_class *class = hlock_class(lock); | |
2219 | ||
2220 | printk(" Possible unsafe locking scenario:\n\n"); | |
2221 | printk(" CPU0\n"); | |
2222 | printk(" ----\n"); | |
2223 | printk(" lock("); | |
2224 | __print_lock_name(class); | |
2225 | printk(");\n"); | |
2226 | printk(" <Interrupt>\n"); | |
2227 | printk(" lock("); | |
2228 | __print_lock_name(class); | |
2229 | printk(");\n"); | |
2230 | printk("\n *** DEADLOCK ***\n\n"); | |
2231 | } | |
2232 | ||
8e18257d PZ |
2233 | static int |
2234 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2235 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2236 | { | |
2237 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2238 | return 0; | |
2239 | ||
b3fbab05 PM |
2240 | printk("\n"); |
2241 | printk("=================================\n"); | |
2242 | printk("[ INFO: inconsistent lock state ]\n"); | |
fbdc4b9a | 2243 | print_kernel_ident(); |
b3fbab05 | 2244 | printk("---------------------------------\n"); |
8e18257d PZ |
2245 | |
2246 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2247 | usage_str[prev_bit], usage_str[new_bit]); | |
2248 | ||
2249 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2250 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2251 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2252 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2253 | trace_hardirqs_enabled(curr), | |
2254 | trace_softirqs_enabled(curr)); | |
2255 | print_lock(this); | |
2256 | ||
2257 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2258 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2259 | |
2260 | print_irqtrace_events(curr); | |
2261 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2262 | print_usage_bug_scenario(this); |
2263 | ||
8e18257d PZ |
2264 | lockdep_print_held_locks(curr); |
2265 | ||
2266 | printk("\nstack backtrace:\n"); | |
2267 | dump_stack(); | |
2268 | ||
2269 | return 0; | |
2270 | } | |
2271 | ||
2272 | /* | |
2273 | * Print out an error if an invalid bit is set: | |
2274 | */ | |
2275 | static inline int | |
2276 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2277 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2278 | { | |
f82b217e | 2279 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2280 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2281 | return 1; | |
2282 | } | |
2283 | ||
2284 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2285 | enum lock_usage_bit new_bit); | |
2286 | ||
81d68a96 | 2287 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2288 | |
2289 | /* | |
2290 | * print irq inversion bug: | |
2291 | */ | |
2292 | static int | |
24208ca7 ML |
2293 | print_irq_inversion_bug(struct task_struct *curr, |
2294 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2295 | struct held_lock *this, int forwards, |
2296 | const char *irqclass) | |
2297 | { | |
dad3d743 SR |
2298 | struct lock_list *entry = other; |
2299 | struct lock_list *middle = NULL; | |
2300 | int depth; | |
2301 | ||
74c383f1 | 2302 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2303 | return 0; |
2304 | ||
b3fbab05 PM |
2305 | printk("\n"); |
2306 | printk("=========================================================\n"); | |
2307 | printk("[ INFO: possible irq lock inversion dependency detected ]\n"); | |
fbdc4b9a | 2308 | print_kernel_ident(); |
b3fbab05 | 2309 | printk("---------------------------------------------------------\n"); |
fbb9ce95 | 2310 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2311 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2312 | print_lock(this); |
2313 | if (forwards) | |
26575e28 | 2314 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2315 | else |
26575e28 | 2316 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2317 | print_lock_name(other->class); |
fbb9ce95 IM |
2318 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2319 | ||
2320 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2321 | |
2322 | /* Find a middle lock (if one exists) */ | |
2323 | depth = get_lock_depth(other); | |
2324 | do { | |
2325 | if (depth == 0 && (entry != root)) { | |
2326 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2327 | break; | |
2328 | } | |
2329 | middle = entry; | |
2330 | entry = get_lock_parent(entry); | |
2331 | depth--; | |
2332 | } while (entry && entry != root && (depth >= 0)); | |
2333 | if (forwards) | |
2334 | print_irq_lock_scenario(root, other, | |
2335 | middle ? middle->class : root->class, other->class); | |
2336 | else | |
2337 | print_irq_lock_scenario(other, root, | |
2338 | middle ? middle->class : other->class, root->class); | |
2339 | ||
fbb9ce95 IM |
2340 | lockdep_print_held_locks(curr); |
2341 | ||
24208ca7 ML |
2342 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2343 | if (!save_trace(&root->trace)) | |
2344 | return 0; | |
2345 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2346 | |
2347 | printk("\nstack backtrace:\n"); | |
2348 | dump_stack(); | |
2349 | ||
2350 | return 0; | |
2351 | } | |
2352 | ||
2353 | /* | |
2354 | * Prove that in the forwards-direction subgraph starting at <this> | |
2355 | * there is no lock matching <mask>: | |
2356 | */ | |
2357 | static int | |
2358 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2359 | enum lock_usage_bit bit, const char *irqclass) | |
2360 | { | |
2361 | int ret; | |
d7aaba14 ML |
2362 | struct lock_list root; |
2363 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2364 | |
d7aaba14 ML |
2365 | root.parent = NULL; |
2366 | root.class = hlock_class(this); | |
2367 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2368 | if (ret < 0) |
2369 | return print_bfs_bug(ret); | |
2370 | if (ret == 1) | |
2371 | return ret; | |
fbb9ce95 | 2372 | |
24208ca7 | 2373 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2374 | this, 1, irqclass); |
fbb9ce95 IM |
2375 | } |
2376 | ||
2377 | /* | |
2378 | * Prove that in the backwards-direction subgraph starting at <this> | |
2379 | * there is no lock matching <mask>: | |
2380 | */ | |
2381 | static int | |
2382 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2383 | enum lock_usage_bit bit, const char *irqclass) | |
2384 | { | |
2385 | int ret; | |
d7aaba14 ML |
2386 | struct lock_list root; |
2387 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2388 | |
d7aaba14 ML |
2389 | root.parent = NULL; |
2390 | root.class = hlock_class(this); | |
2391 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2392 | if (ret < 0) |
2393 | return print_bfs_bug(ret); | |
2394 | if (ret == 1) | |
2395 | return ret; | |
fbb9ce95 | 2396 | |
24208ca7 | 2397 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2398 | this, 0, irqclass); |
fbb9ce95 IM |
2399 | } |
2400 | ||
3117df04 | 2401 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2402 | { |
2403 | printk("irq event stamp: %u\n", curr->irq_events); | |
2404 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2405 | print_ip_sym(curr->hardirq_enable_ip); | |
2406 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2407 | print_ip_sym(curr->hardirq_disable_ip); | |
2408 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2409 | print_ip_sym(curr->softirq_enable_ip); | |
2410 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2411 | print_ip_sym(curr->softirq_disable_ip); | |
2412 | } | |
2413 | ||
cd95302d | 2414 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2415 | { |
8e18257d PZ |
2416 | #if HARDIRQ_VERBOSE |
2417 | return class_filter(class); | |
2418 | #endif | |
fbb9ce95 IM |
2419 | return 0; |
2420 | } | |
2421 | ||
cd95302d | 2422 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2423 | { |
8e18257d PZ |
2424 | #if SOFTIRQ_VERBOSE |
2425 | return class_filter(class); | |
2426 | #endif | |
2427 | return 0; | |
fbb9ce95 IM |
2428 | } |
2429 | ||
cd95302d | 2430 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2431 | { |
2432 | #if RECLAIM_VERBOSE | |
2433 | return class_filter(class); | |
2434 | #endif | |
2435 | return 0; | |
2436 | } | |
2437 | ||
fbb9ce95 IM |
2438 | #define STRICT_READ_CHECKS 1 |
2439 | ||
cd95302d PZ |
2440 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2441 | #define LOCKDEP_STATE(__STATE) \ | |
2442 | __STATE##_verbose, | |
2443 | #include "lockdep_states.h" | |
2444 | #undef LOCKDEP_STATE | |
2445 | }; | |
2446 | ||
2447 | static inline int state_verbose(enum lock_usage_bit bit, | |
2448 | struct lock_class *class) | |
2449 | { | |
2450 | return state_verbose_f[bit >> 2](class); | |
2451 | } | |
2452 | ||
42c50d54 PZ |
2453 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2454 | enum lock_usage_bit bit, const char *name); | |
2455 | ||
6a6904d3 | 2456 | static int |
1c21f14e PZ |
2457 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2458 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2459 | { |
f989209e | 2460 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2461 | int read = new_bit & 1; |
42c50d54 PZ |
2462 | int dir = new_bit & 2; |
2463 | ||
38aa2714 PZ |
2464 | /* |
2465 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2466 | * has ENABLED state, which would allow recursion deadlocks. | |
2467 | * | |
2468 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2469 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2470 | */ | |
42c50d54 PZ |
2471 | check_usage_f usage = dir ? |
2472 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2473 | |
38aa2714 PZ |
2474 | /* |
2475 | * Validate that this particular lock does not have conflicting | |
2476 | * usage states. | |
2477 | */ | |
6a6904d3 PZ |
2478 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2479 | return 0; | |
42c50d54 | 2480 | |
38aa2714 PZ |
2481 | /* |
2482 | * Validate that the lock dependencies don't have conflicting usage | |
2483 | * states. | |
2484 | */ | |
2485 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2486 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2487 | return 0; |
780e820b | 2488 | |
38aa2714 PZ |
2489 | /* |
2490 | * Check for read in write conflicts | |
2491 | */ | |
2492 | if (!read) { | |
2493 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2494 | return 0; | |
2495 | ||
2496 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2497 | !usage(curr, this, excl_bit + 1, |
2498 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2499 | return 0; |
2500 | } | |
780e820b | 2501 | |
cd95302d | 2502 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2503 | return 2; |
2504 | ||
2505 | return 1; | |
2506 | } | |
2507 | ||
cf40bd16 | 2508 | enum mark_type { |
36bfb9bb PZ |
2509 | #define LOCKDEP_STATE(__STATE) __STATE, |
2510 | #include "lockdep_states.h" | |
2511 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2512 | }; |
2513 | ||
fbb9ce95 IM |
2514 | /* |
2515 | * Mark all held locks with a usage bit: | |
2516 | */ | |
1d09daa5 | 2517 | static int |
cf40bd16 | 2518 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2519 | { |
2520 | enum lock_usage_bit usage_bit; | |
2521 | struct held_lock *hlock; | |
2522 | int i; | |
2523 | ||
2524 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2525 | hlock = curr->held_locks + i; | |
2526 | ||
cf2ad4d1 PZ |
2527 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2528 | if (hlock->read) | |
2529 | usage_bit += 1; /* READ */ | |
2530 | ||
2531 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2532 | |
34d0ed5e | 2533 | if (!hlock->check) |
efbe2eee PZ |
2534 | continue; |
2535 | ||
4ff773bb | 2536 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2537 | return 0; |
2538 | } | |
2539 | ||
2540 | return 1; | |
2541 | } | |
2542 | ||
fbb9ce95 IM |
2543 | /* |
2544 | * Hardirqs will be enabled: | |
2545 | */ | |
dd4e5d3a | 2546 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2547 | { |
2548 | struct task_struct *curr = current; | |
fbb9ce95 | 2549 | |
fbb9ce95 IM |
2550 | /* we'll do an OFF -> ON transition: */ |
2551 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2552 | |
fbb9ce95 IM |
2553 | /* |
2554 | * We are going to turn hardirqs on, so set the | |
2555 | * usage bit for all held locks: | |
2556 | */ | |
cf40bd16 | 2557 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2558 | return; |
2559 | /* | |
2560 | * If we have softirqs enabled, then set the usage | |
2561 | * bit for all held locks. (disabled hardirqs prevented | |
2562 | * this bit from being set before) | |
2563 | */ | |
2564 | if (curr->softirqs_enabled) | |
cf40bd16 | 2565 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2566 | return; |
2567 | ||
8e18257d PZ |
2568 | curr->hardirq_enable_ip = ip; |
2569 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2570 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2571 | } |
dd4e5d3a | 2572 | |
b35f8305 | 2573 | __visible void trace_hardirqs_on_caller(unsigned long ip) |
dd4e5d3a PZ |
2574 | { |
2575 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2576 | ||
2577 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2578 | return; | |
2579 | ||
7d36b26b PZ |
2580 | if (unlikely(current->hardirqs_enabled)) { |
2581 | /* | |
2582 | * Neither irq nor preemption are disabled here | |
2583 | * so this is racy by nature but losing one hit | |
2584 | * in a stat is not a big deal. | |
2585 | */ | |
2586 | __debug_atomic_inc(redundant_hardirqs_on); | |
2587 | return; | |
2588 | } | |
2589 | ||
0119fee4 PZ |
2590 | /* |
2591 | * We're enabling irqs and according to our state above irqs weren't | |
2592 | * already enabled, yet we find the hardware thinks they are in fact | |
2593 | * enabled.. someone messed up their IRQ state tracing. | |
2594 | */ | |
dd4e5d3a PZ |
2595 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2596 | return; | |
2597 | ||
0119fee4 PZ |
2598 | /* |
2599 | * See the fine text that goes along with this variable definition. | |
2600 | */ | |
7d36b26b PZ |
2601 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2602 | return; | |
2603 | ||
0119fee4 PZ |
2604 | /* |
2605 | * Can't allow enabling interrupts while in an interrupt handler, | |
2606 | * that's general bad form and such. Recursion, limited stack etc.. | |
2607 | */ | |
7d36b26b PZ |
2608 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
2609 | return; | |
2610 | ||
dd4e5d3a PZ |
2611 | current->lockdep_recursion = 1; |
2612 | __trace_hardirqs_on_caller(ip); | |
2613 | current->lockdep_recursion = 0; | |
2614 | } | |
81d68a96 | 2615 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2616 | |
1d09daa5 | 2617 | void trace_hardirqs_on(void) |
81d68a96 SR |
2618 | { |
2619 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2620 | } | |
8e18257d PZ |
2621 | EXPORT_SYMBOL(trace_hardirqs_on); |
2622 | ||
2623 | /* | |
2624 | * Hardirqs were disabled: | |
2625 | */ | |
b35f8305 | 2626 | __visible void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2627 | { |
2628 | struct task_struct *curr = current; | |
2629 | ||
6afe40b4 | 2630 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2631 | |
8e18257d PZ |
2632 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2633 | return; | |
2634 | ||
0119fee4 PZ |
2635 | /* |
2636 | * So we're supposed to get called after you mask local IRQs, but for | |
2637 | * some reason the hardware doesn't quite think you did a proper job. | |
2638 | */ | |
8e18257d PZ |
2639 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2640 | return; | |
2641 | ||
2642 | if (curr->hardirqs_enabled) { | |
2643 | /* | |
2644 | * We have done an ON -> OFF transition: | |
2645 | */ | |
2646 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2647 | curr->hardirq_disable_ip = ip; |
8e18257d | 2648 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2649 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2650 | } else |
bd6d29c2 | 2651 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2652 | } |
81d68a96 | 2653 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2654 | |
1d09daa5 | 2655 | void trace_hardirqs_off(void) |
81d68a96 SR |
2656 | { |
2657 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2658 | } | |
8e18257d PZ |
2659 | EXPORT_SYMBOL(trace_hardirqs_off); |
2660 | ||
2661 | /* | |
2662 | * Softirqs will be enabled: | |
2663 | */ | |
2664 | void trace_softirqs_on(unsigned long ip) | |
2665 | { | |
2666 | struct task_struct *curr = current; | |
2667 | ||
dd4e5d3a | 2668 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2669 | return; |
2670 | ||
0119fee4 PZ |
2671 | /* |
2672 | * We fancy IRQs being disabled here, see softirq.c, avoids | |
2673 | * funny state and nesting things. | |
2674 | */ | |
8e18257d PZ |
2675 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2676 | return; | |
2677 | ||
2678 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2679 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2680 | return; |
2681 | } | |
2682 | ||
dd4e5d3a | 2683 | current->lockdep_recursion = 1; |
8e18257d PZ |
2684 | /* |
2685 | * We'll do an OFF -> ON transition: | |
2686 | */ | |
2687 | curr->softirqs_enabled = 1; | |
2688 | curr->softirq_enable_ip = ip; | |
2689 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2690 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2691 | /* |
2692 | * We are going to turn softirqs on, so set the | |
2693 | * usage bit for all held locks, if hardirqs are | |
2694 | * enabled too: | |
2695 | */ | |
2696 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2697 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2698 | current->lockdep_recursion = 0; |
8e18257d PZ |
2699 | } |
2700 | ||
2701 | /* | |
2702 | * Softirqs were disabled: | |
2703 | */ | |
2704 | void trace_softirqs_off(unsigned long ip) | |
2705 | { | |
2706 | struct task_struct *curr = current; | |
2707 | ||
dd4e5d3a | 2708 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2709 | return; |
2710 | ||
0119fee4 PZ |
2711 | /* |
2712 | * We fancy IRQs being disabled here, see softirq.c | |
2713 | */ | |
8e18257d PZ |
2714 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2715 | return; | |
2716 | ||
2717 | if (curr->softirqs_enabled) { | |
2718 | /* | |
2719 | * We have done an ON -> OFF transition: | |
2720 | */ | |
2721 | curr->softirqs_enabled = 0; | |
2722 | curr->softirq_disable_ip = ip; | |
2723 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2724 | debug_atomic_inc(softirqs_off_events); |
0119fee4 PZ |
2725 | /* |
2726 | * Whoops, we wanted softirqs off, so why aren't they? | |
2727 | */ | |
8e18257d PZ |
2728 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2729 | } else | |
bd6d29c2 | 2730 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2731 | } |
2732 | ||
2f850181 | 2733 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2734 | { |
2735 | struct task_struct *curr = current; | |
2736 | ||
2737 | if (unlikely(!debug_locks)) | |
2738 | return; | |
2739 | ||
2740 | /* no reclaim without waiting on it */ | |
d0164adc | 2741 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) |
cf40bd16 NP |
2742 | return; |
2743 | ||
2744 | /* this guy won't enter reclaim */ | |
2745 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2746 | return; | |
2747 | ||
2748 | /* We're only interested __GFP_FS allocations for now */ | |
2749 | if (!(gfp_mask & __GFP_FS)) | |
2750 | return; | |
2751 | ||
0119fee4 PZ |
2752 | /* |
2753 | * Oi! Can't be having __GFP_FS allocations with IRQs disabled. | |
2754 | */ | |
2f850181 | 2755 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2756 | return; |
2757 | ||
2758 | mark_held_locks(curr, RECLAIM_FS); | |
2759 | } | |
2760 | ||
2f850181 PZ |
2761 | static void check_flags(unsigned long flags); |
2762 | ||
2763 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2764 | { | |
2765 | unsigned long flags; | |
2766 | ||
2767 | if (unlikely(current->lockdep_recursion)) | |
2768 | return; | |
2769 | ||
2770 | raw_local_irq_save(flags); | |
2771 | check_flags(flags); | |
2772 | current->lockdep_recursion = 1; | |
2773 | __lockdep_trace_alloc(gfp_mask, flags); | |
2774 | current->lockdep_recursion = 0; | |
2775 | raw_local_irq_restore(flags); | |
2776 | } | |
2777 | ||
8e18257d PZ |
2778 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2779 | { | |
2780 | /* | |
2781 | * If non-trylock use in a hardirq or softirq context, then | |
2782 | * mark the lock as used in these contexts: | |
2783 | */ | |
2784 | if (!hlock->trylock) { | |
2785 | if (hlock->read) { | |
2786 | if (curr->hardirq_context) | |
2787 | if (!mark_lock(curr, hlock, | |
2788 | LOCK_USED_IN_HARDIRQ_READ)) | |
2789 | return 0; | |
2790 | if (curr->softirq_context) | |
2791 | if (!mark_lock(curr, hlock, | |
2792 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2793 | return 0; | |
2794 | } else { | |
2795 | if (curr->hardirq_context) | |
2796 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2797 | return 0; | |
2798 | if (curr->softirq_context) | |
2799 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2800 | return 0; | |
2801 | } | |
2802 | } | |
2803 | if (!hlock->hardirqs_off) { | |
2804 | if (hlock->read) { | |
2805 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2806 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2807 | return 0; |
2808 | if (curr->softirqs_enabled) | |
2809 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2810 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2811 | return 0; |
2812 | } else { | |
2813 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2814 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2815 | return 0; |
2816 | if (curr->softirqs_enabled) | |
2817 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2818 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2819 | return 0; |
2820 | } | |
2821 | } | |
2822 | ||
cf40bd16 NP |
2823 | /* |
2824 | * We reuse the irq context infrastructure more broadly as a general | |
2825 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2826 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2827 | * allocation). | |
2828 | */ | |
2829 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2830 | if (hlock->read) { | |
2831 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2832 | return 0; | |
2833 | } else { | |
2834 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2835 | return 0; | |
2836 | } | |
2837 | } | |
2838 | ||
8e18257d PZ |
2839 | return 1; |
2840 | } | |
2841 | ||
2842 | static int separate_irq_context(struct task_struct *curr, | |
2843 | struct held_lock *hlock) | |
2844 | { | |
2845 | unsigned int depth = curr->lockdep_depth; | |
2846 | ||
2847 | /* | |
2848 | * Keep track of points where we cross into an interrupt context: | |
2849 | */ | |
2850 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2851 | curr->softirq_context; | |
2852 | if (depth) { | |
2853 | struct held_lock *prev_hlock; | |
2854 | ||
2855 | prev_hlock = curr->held_locks + depth-1; | |
2856 | /* | |
2857 | * If we cross into another context, reset the | |
2858 | * hash key (this also prevents the checking and the | |
2859 | * adding of the dependency to 'prev'): | |
2860 | */ | |
2861 | if (prev_hlock->irq_context != hlock->irq_context) | |
2862 | return 1; | |
2863 | } | |
2864 | return 0; | |
fbb9ce95 IM |
2865 | } |
2866 | ||
0119fee4 | 2867 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 | 2868 | |
8e18257d PZ |
2869 | static inline |
2870 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2871 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2872 | { |
0119fee4 | 2873 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
8e18257d PZ |
2874 | return 1; |
2875 | } | |
fbb9ce95 | 2876 | |
8e18257d PZ |
2877 | static inline int mark_irqflags(struct task_struct *curr, |
2878 | struct held_lock *hlock) | |
2879 | { | |
2880 | return 1; | |
2881 | } | |
fbb9ce95 | 2882 | |
8e18257d PZ |
2883 | static inline int separate_irq_context(struct task_struct *curr, |
2884 | struct held_lock *hlock) | |
2885 | { | |
2886 | return 0; | |
fbb9ce95 IM |
2887 | } |
2888 | ||
868a23a8 PZ |
2889 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2890 | { | |
2891 | } | |
2892 | ||
0119fee4 | 2893 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
fbb9ce95 IM |
2894 | |
2895 | /* | |
8e18257d | 2896 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2897 | */ |
1d09daa5 | 2898 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2899 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2900 | { |
8e18257d | 2901 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2902 | |
2903 | /* | |
8e18257d PZ |
2904 | * If already set then do not dirty the cacheline, |
2905 | * nor do any checks: | |
fbb9ce95 | 2906 | */ |
f82b217e | 2907 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2908 | return 1; |
2909 | ||
2910 | if (!graph_lock()) | |
2911 | return 0; | |
fbb9ce95 | 2912 | /* |
25985edc | 2913 | * Make sure we didn't race: |
fbb9ce95 | 2914 | */ |
f82b217e | 2915 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2916 | graph_unlock(); |
2917 | return 1; | |
2918 | } | |
fbb9ce95 | 2919 | |
f82b217e | 2920 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2921 | |
f82b217e | 2922 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2923 | return 0; |
fbb9ce95 | 2924 | |
8e18257d | 2925 | switch (new_bit) { |
5346417e PZ |
2926 | #define LOCKDEP_STATE(__STATE) \ |
2927 | case LOCK_USED_IN_##__STATE: \ | |
2928 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2929 | case LOCK_ENABLED_##__STATE: \ | |
2930 | case LOCK_ENABLED_##__STATE##_READ: | |
2931 | #include "lockdep_states.h" | |
2932 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2933 | ret = mark_lock_irq(curr, this, new_bit); |
2934 | if (!ret) | |
2935 | return 0; | |
2936 | break; | |
2937 | case LOCK_USED: | |
bd6d29c2 | 2938 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
2939 | break; |
2940 | default: | |
2941 | if (!debug_locks_off_graph_unlock()) | |
2942 | return 0; | |
2943 | WARN_ON(1); | |
2944 | return 0; | |
2945 | } | |
fbb9ce95 | 2946 | |
8e18257d PZ |
2947 | graph_unlock(); |
2948 | ||
2949 | /* | |
2950 | * We must printk outside of the graph_lock: | |
2951 | */ | |
2952 | if (ret == 2) { | |
2953 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2954 | print_lock(this); | |
2955 | print_irqtrace_events(curr); | |
2956 | dump_stack(); | |
2957 | } | |
2958 | ||
2959 | return ret; | |
2960 | } | |
fbb9ce95 IM |
2961 | |
2962 | /* | |
2963 | * Initialize a lock instance's lock-class mapping info: | |
2964 | */ | |
2965 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2966 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2967 | { |
d3d03d4f YZ |
2968 | int i; |
2969 | ||
2970 | kmemcheck_mark_initialized(lock, sizeof(*lock)); | |
2971 | ||
2972 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) | |
2973 | lock->class_cache[i] = NULL; | |
62016250 | 2974 | |
c8a25005 PZ |
2975 | #ifdef CONFIG_LOCK_STAT |
2976 | lock->cpu = raw_smp_processor_id(); | |
2977 | #endif | |
2978 | ||
0119fee4 PZ |
2979 | /* |
2980 | * Can't be having no nameless bastards around this place! | |
2981 | */ | |
c8a25005 PZ |
2982 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
2983 | lock->name = "NULL"; | |
fbb9ce95 | 2984 | return; |
c8a25005 PZ |
2985 | } |
2986 | ||
2987 | lock->name = name; | |
fbb9ce95 | 2988 | |
0119fee4 PZ |
2989 | /* |
2990 | * No key, no joy, we need to hash something. | |
2991 | */ | |
fbb9ce95 IM |
2992 | if (DEBUG_LOCKS_WARN_ON(!key)) |
2993 | return; | |
fbb9ce95 IM |
2994 | /* |
2995 | * Sanity check, the lock-class key must be persistent: | |
2996 | */ | |
2997 | if (!static_obj(key)) { | |
2998 | printk("BUG: key %p not in .data!\n", key); | |
0119fee4 PZ |
2999 | /* |
3000 | * What it says above ^^^^^, I suggest you read it. | |
3001 | */ | |
fbb9ce95 IM |
3002 | DEBUG_LOCKS_WARN_ON(1); |
3003 | return; | |
3004 | } | |
fbb9ce95 | 3005 | lock->key = key; |
c8a25005 PZ |
3006 | |
3007 | if (unlikely(!debug_locks)) | |
3008 | return; | |
3009 | ||
35a9393c PZ |
3010 | if (subclass) { |
3011 | unsigned long flags; | |
3012 | ||
3013 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) | |
3014 | return; | |
3015 | ||
3016 | raw_local_irq_save(flags); | |
3017 | current->lockdep_recursion = 1; | |
4dfbb9d8 | 3018 | register_lock_class(lock, subclass, 1); |
35a9393c PZ |
3019 | current->lockdep_recursion = 0; |
3020 | raw_local_irq_restore(flags); | |
3021 | } | |
fbb9ce95 | 3022 | } |
fbb9ce95 IM |
3023 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
3024 | ||
1704f47b | 3025 | struct lock_class_key __lockdep_no_validate__; |
ea6749c7 | 3026 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
1704f47b | 3027 | |
d0945950 ML |
3028 | static int |
3029 | print_lock_nested_lock_not_held(struct task_struct *curr, | |
3030 | struct held_lock *hlock, | |
3031 | unsigned long ip) | |
3032 | { | |
3033 | if (!debug_locks_off()) | |
3034 | return 0; | |
3035 | if (debug_locks_silent) | |
3036 | return 0; | |
3037 | ||
3038 | printk("\n"); | |
3039 | printk("==================================\n"); | |
3040 | printk("[ BUG: Nested lock was not taken ]\n"); | |
3041 | print_kernel_ident(); | |
3042 | printk("----------------------------------\n"); | |
3043 | ||
3044 | printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); | |
3045 | print_lock(hlock); | |
3046 | ||
3047 | printk("\nbut this task is not holding:\n"); | |
3048 | printk("%s\n", hlock->nest_lock->name); | |
3049 | ||
3050 | printk("\nstack backtrace:\n"); | |
3051 | dump_stack(); | |
3052 | ||
3053 | printk("\nother info that might help us debug this:\n"); | |
3054 | lockdep_print_held_locks(curr); | |
3055 | ||
3056 | printk("\nstack backtrace:\n"); | |
3057 | dump_stack(); | |
3058 | ||
3059 | return 0; | |
3060 | } | |
3061 | ||
3062 | static int __lock_is_held(struct lockdep_map *lock); | |
3063 | ||
fbb9ce95 IM |
3064 | /* |
3065 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
3066 | * We maintain the dependency maps and validate the locking attempt: | |
3067 | */ | |
3068 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
3069 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e | 3070 | struct lockdep_map *nest_lock, unsigned long ip, |
21199f27 | 3071 | int references, int pin_count) |
fbb9ce95 IM |
3072 | { |
3073 | struct task_struct *curr = current; | |
d6d897ce | 3074 | struct lock_class *class = NULL; |
fbb9ce95 | 3075 | struct held_lock *hlock; |
fbb9ce95 IM |
3076 | unsigned int depth, id; |
3077 | int chain_head = 0; | |
bb97a91e | 3078 | int class_idx; |
fbb9ce95 IM |
3079 | u64 chain_key; |
3080 | ||
3081 | if (unlikely(!debug_locks)) | |
3082 | return 0; | |
3083 | ||
0119fee4 PZ |
3084 | /* |
3085 | * Lockdep should run with IRQs disabled, otherwise we could | |
3086 | * get an interrupt which would want to take locks, which would | |
3087 | * end up in lockdep and have you got a head-ache already? | |
3088 | */ | |
fbb9ce95 IM |
3089 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
3090 | return 0; | |
3091 | ||
fb9edbe9 ON |
3092 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
3093 | check = 0; | |
1704f47b | 3094 | |
62016250 HM |
3095 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
3096 | class = lock->class_cache[subclass]; | |
d6d897ce | 3097 | /* |
62016250 | 3098 | * Not cached? |
d6d897ce | 3099 | */ |
fbb9ce95 | 3100 | if (unlikely(!class)) { |
4dfbb9d8 | 3101 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
3102 | if (!class) |
3103 | return 0; | |
3104 | } | |
bd6d29c2 | 3105 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
3106 | if (very_verbose(class)) { |
3107 | printk("\nacquire class [%p] %s", class->key, class->name); | |
3108 | if (class->name_version > 1) | |
3109 | printk("#%d", class->name_version); | |
3110 | printk("\n"); | |
3111 | dump_stack(); | |
3112 | } | |
3113 | ||
3114 | /* | |
3115 | * Add the lock to the list of currently held locks. | |
3116 | * (we dont increase the depth just yet, up until the | |
3117 | * dependency checks are done) | |
3118 | */ | |
3119 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3120 | /* |
3121 | * Ran out of static storage for our per-task lock stack again have we? | |
3122 | */ | |
fbb9ce95 IM |
3123 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
3124 | return 0; | |
3125 | ||
bb97a91e PZ |
3126 | class_idx = class - lock_classes + 1; |
3127 | ||
3128 | if (depth) { | |
3129 | hlock = curr->held_locks + depth - 1; | |
3130 | if (hlock->class_idx == class_idx && nest_lock) { | |
3131 | if (hlock->references) | |
3132 | hlock->references++; | |
3133 | else | |
3134 | hlock->references = 2; | |
3135 | ||
3136 | return 1; | |
3137 | } | |
3138 | } | |
3139 | ||
fbb9ce95 | 3140 | hlock = curr->held_locks + depth; |
0119fee4 PZ |
3141 | /* |
3142 | * Plain impossible, we just registered it and checked it weren't no | |
3143 | * NULL like.. I bet this mushroom I ate was good! | |
3144 | */ | |
f82b217e DJ |
3145 | if (DEBUG_LOCKS_WARN_ON(!class)) |
3146 | return 0; | |
bb97a91e | 3147 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
3148 | hlock->acquire_ip = ip; |
3149 | hlock->instance = lock; | |
7531e2f3 | 3150 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
3151 | hlock->trylock = trylock; |
3152 | hlock->read = read; | |
3153 | hlock->check = check; | |
6951b12a | 3154 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 3155 | hlock->references = references; |
f20786ff PZ |
3156 | #ifdef CONFIG_LOCK_STAT |
3157 | hlock->waittime_stamp = 0; | |
3365e779 | 3158 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3159 | #endif |
21199f27 | 3160 | hlock->pin_count = pin_count; |
fbb9ce95 | 3161 | |
fb9edbe9 | 3162 | if (check && !mark_irqflags(curr, hlock)) |
8e18257d PZ |
3163 | return 0; |
3164 | ||
fbb9ce95 | 3165 | /* mark it as used: */ |
4ff773bb | 3166 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3167 | return 0; |
8e18257d | 3168 | |
fbb9ce95 | 3169 | /* |
17aacfb9 | 3170 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3171 | * lock keys along the dependency chain. We save the hash value |
3172 | * at every step so that we can get the current hash easily | |
3173 | * after unlock. The chain hash is then used to cache dependency | |
3174 | * results. | |
3175 | * | |
3176 | * The 'key ID' is what is the most compact key value to drive | |
3177 | * the hash, not class->key. | |
3178 | */ | |
3179 | id = class - lock_classes; | |
0119fee4 PZ |
3180 | /* |
3181 | * Whoops, we did it again.. ran straight out of our static allocation. | |
3182 | */ | |
fbb9ce95 IM |
3183 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
3184 | return 0; | |
3185 | ||
3186 | chain_key = curr->curr_chain_key; | |
3187 | if (!depth) { | |
0119fee4 PZ |
3188 | /* |
3189 | * How can we have a chain hash when we ain't got no keys?! | |
3190 | */ | |
fbb9ce95 IM |
3191 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
3192 | return 0; | |
3193 | chain_head = 1; | |
3194 | } | |
3195 | ||
3196 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3197 | if (separate_irq_context(curr, hlock)) { |
3198 | chain_key = 0; | |
3199 | chain_head = 1; | |
fbb9ce95 | 3200 | } |
fbb9ce95 | 3201 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 3202 | |
d0945950 ML |
3203 | if (nest_lock && !__lock_is_held(nest_lock)) |
3204 | return print_lock_nested_lock_not_held(curr, hlock, ip); | |
3205 | ||
3aa416b0 | 3206 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3207 | return 0; |
381a2292 | 3208 | |
3aa416b0 | 3209 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3210 | curr->lockdep_depth++; |
3211 | check_chain_key(curr); | |
60e114d1 JP |
3212 | #ifdef CONFIG_DEBUG_LOCKDEP |
3213 | if (unlikely(!debug_locks)) | |
3214 | return 0; | |
3215 | #endif | |
fbb9ce95 IM |
3216 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3217 | debug_locks_off(); | |
2c522836 DJ |
3218 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
3219 | printk(KERN_DEBUG "depth: %i max: %lu!\n", | |
c0540606 | 3220 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
c0540606 BG |
3221 | |
3222 | lockdep_print_held_locks(current); | |
3223 | debug_show_all_locks(); | |
eedeeabd | 3224 | dump_stack(); |
c0540606 | 3225 | |
fbb9ce95 IM |
3226 | return 0; |
3227 | } | |
381a2292 | 3228 | |
fbb9ce95 IM |
3229 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3230 | max_lockdep_depth = curr->lockdep_depth; | |
3231 | ||
3232 | return 1; | |
3233 | } | |
3234 | ||
3235 | static int | |
f86f7554 | 3236 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
fbb9ce95 IM |
3237 | unsigned long ip) |
3238 | { | |
3239 | if (!debug_locks_off()) | |
3240 | return 0; | |
3241 | if (debug_locks_silent) | |
3242 | return 0; | |
3243 | ||
b3fbab05 PM |
3244 | printk("\n"); |
3245 | printk("=====================================\n"); | |
3246 | printk("[ BUG: bad unlock balance detected! ]\n"); | |
fbdc4b9a | 3247 | print_kernel_ident(); |
b3fbab05 | 3248 | printk("-------------------------------------\n"); |
fbb9ce95 | 3249 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3250 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3251 | print_lockdep_cache(lock); |
3252 | printk(") at:\n"); | |
3253 | print_ip_sym(ip); | |
3254 | printk("but there are no more locks to release!\n"); | |
3255 | printk("\nother info that might help us debug this:\n"); | |
3256 | lockdep_print_held_locks(curr); | |
3257 | ||
3258 | printk("\nstack backtrace:\n"); | |
3259 | dump_stack(); | |
3260 | ||
3261 | return 0; | |
3262 | } | |
3263 | ||
bb97a91e PZ |
3264 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3265 | { | |
3266 | if (hlock->instance == lock) | |
3267 | return 1; | |
3268 | ||
3269 | if (hlock->references) { | |
62016250 | 3270 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3271 | |
3272 | if (!class) | |
3273 | class = look_up_lock_class(lock, 0); | |
3274 | ||
80e0401e PZ |
3275 | /* |
3276 | * If look_up_lock_class() failed to find a class, we're trying | |
3277 | * to test if we hold a lock that has never yet been acquired. | |
3278 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3279 | * holding it either, so report failure. | |
3280 | */ | |
3281 | if (!class) | |
bb97a91e PZ |
3282 | return 0; |
3283 | ||
0119fee4 PZ |
3284 | /* |
3285 | * References, but not a lock we're actually ref-counting? | |
3286 | * State got messed up, follow the sites that change ->references | |
3287 | * and try to make sense of it. | |
3288 | */ | |
bb97a91e PZ |
3289 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
3290 | return 0; | |
3291 | ||
3292 | if (hlock->class_idx == class - lock_classes + 1) | |
3293 | return 1; | |
3294 | } | |
3295 | ||
3296 | return 0; | |
3297 | } | |
3298 | ||
64aa348e | 3299 | static int |
00ef9f73 PZ |
3300 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3301 | struct lock_class_key *key, unsigned int subclass, | |
3302 | unsigned long ip) | |
64aa348e PZ |
3303 | { |
3304 | struct task_struct *curr = current; | |
3305 | struct held_lock *hlock, *prev_hlock; | |
3306 | struct lock_class *class; | |
3307 | unsigned int depth; | |
3308 | int i; | |
3309 | ||
3310 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3311 | /* |
3312 | * This function is about (re)setting the class of a held lock, | |
3313 | * yet we're not actually holding any locks. Naughty user! | |
3314 | */ | |
64aa348e PZ |
3315 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3316 | return 0; | |
3317 | ||
3318 | prev_hlock = NULL; | |
3319 | for (i = depth-1; i >= 0; i--) { | |
3320 | hlock = curr->held_locks + i; | |
3321 | /* | |
3322 | * We must not cross into another context: | |
3323 | */ | |
3324 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3325 | break; | |
bb97a91e | 3326 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3327 | goto found_it; |
3328 | prev_hlock = hlock; | |
3329 | } | |
f86f7554 | 3330 | return print_unlock_imbalance_bug(curr, lock, ip); |
64aa348e PZ |
3331 | |
3332 | found_it: | |
00ef9f73 | 3333 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3334 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3335 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3336 | |
3337 | curr->lockdep_depth = i; | |
3338 | curr->curr_chain_key = hlock->prev_chain_key; | |
3339 | ||
3340 | for (; i < depth; i++) { | |
3341 | hlock = curr->held_locks + i; | |
3342 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3343 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3344 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3345 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3346 | hlock->references, hlock->pin_count)) |
64aa348e PZ |
3347 | return 0; |
3348 | } | |
3349 | ||
0119fee4 PZ |
3350 | /* |
3351 | * I took it apart and put it back together again, except now I have | |
3352 | * these 'spare' parts.. where shall I put them. | |
3353 | */ | |
64aa348e PZ |
3354 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
3355 | return 0; | |
3356 | return 1; | |
3357 | } | |
3358 | ||
fbb9ce95 | 3359 | /* |
e0f56fd7 PZ |
3360 | * Remove the lock to the list of currently held locks - this gets |
3361 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3362 | * mutex_lock_interruptible()). | |
3363 | * | |
3364 | * @nested is an hysterical artifact, needs a tree wide cleanup. | |
fbb9ce95 IM |
3365 | */ |
3366 | static int | |
e0f56fd7 | 3367 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
fbb9ce95 | 3368 | { |
e0f56fd7 | 3369 | struct task_struct *curr = current; |
fbb9ce95 IM |
3370 | struct held_lock *hlock, *prev_hlock; |
3371 | unsigned int depth; | |
3372 | int i; | |
3373 | ||
e0f56fd7 PZ |
3374 | if (unlikely(!debug_locks)) |
3375 | return 0; | |
3376 | ||
fbb9ce95 | 3377 | depth = curr->lockdep_depth; |
0119fee4 PZ |
3378 | /* |
3379 | * So we're all set to release this lock.. wait what lock? We don't | |
3380 | * own any locks, you've been drinking again? | |
3381 | */ | |
e0f56fd7 PZ |
3382 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
3383 | return print_unlock_imbalance_bug(curr, lock, ip); | |
fbb9ce95 | 3384 | |
e0f56fd7 PZ |
3385 | /* |
3386 | * Check whether the lock exists in the current stack | |
3387 | * of held locks: | |
3388 | */ | |
fbb9ce95 IM |
3389 | prev_hlock = NULL; |
3390 | for (i = depth-1; i >= 0; i--) { | |
3391 | hlock = curr->held_locks + i; | |
3392 | /* | |
3393 | * We must not cross into another context: | |
3394 | */ | |
3395 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3396 | break; | |
bb97a91e | 3397 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3398 | goto found_it; |
3399 | prev_hlock = hlock; | |
3400 | } | |
f86f7554 | 3401 | return print_unlock_imbalance_bug(curr, lock, ip); |
fbb9ce95 IM |
3402 | |
3403 | found_it: | |
bb97a91e PZ |
3404 | if (hlock->instance == lock) |
3405 | lock_release_holdtime(hlock); | |
3406 | ||
a24fc60d PZ |
3407 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
3408 | ||
bb97a91e PZ |
3409 | if (hlock->references) { |
3410 | hlock->references--; | |
3411 | if (hlock->references) { | |
3412 | /* | |
3413 | * We had, and after removing one, still have | |
3414 | * references, the current lock stack is still | |
3415 | * valid. We're done! | |
3416 | */ | |
3417 | return 1; | |
3418 | } | |
3419 | } | |
f20786ff | 3420 | |
fbb9ce95 IM |
3421 | /* |
3422 | * We have the right lock to unlock, 'hlock' points to it. | |
3423 | * Now we remove it from the stack, and add back the other | |
3424 | * entries (if any), recalculating the hash along the way: | |
3425 | */ | |
bb97a91e | 3426 | |
fbb9ce95 IM |
3427 | curr->lockdep_depth = i; |
3428 | curr->curr_chain_key = hlock->prev_chain_key; | |
3429 | ||
3430 | for (i++; i < depth; i++) { | |
3431 | hlock = curr->held_locks + i; | |
3432 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3433 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3434 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e | 3435 | hlock->nest_lock, hlock->acquire_ip, |
21199f27 | 3436 | hlock->references, hlock->pin_count)) |
fbb9ce95 IM |
3437 | return 0; |
3438 | } | |
3439 | ||
0119fee4 PZ |
3440 | /* |
3441 | * We had N bottles of beer on the wall, we drank one, but now | |
3442 | * there's not N-1 bottles of beer left on the wall... | |
3443 | */ | |
fbb9ce95 IM |
3444 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
3445 | return 0; | |
f20786ff | 3446 | |
fbb9ce95 IM |
3447 | return 1; |
3448 | } | |
3449 | ||
f607c668 | 3450 | static int __lock_is_held(struct lockdep_map *lock) |
fbb9ce95 | 3451 | { |
f607c668 PZ |
3452 | struct task_struct *curr = current; |
3453 | int i; | |
fbb9ce95 | 3454 | |
f607c668 | 3455 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e | 3456 | struct held_lock *hlock = curr->held_locks + i; |
fbb9ce95 | 3457 | |
bb97a91e | 3458 | if (match_held_lock(hlock, lock)) |
f607c668 PZ |
3459 | return 1; |
3460 | } | |
f20786ff | 3461 | |
f607c668 | 3462 | return 0; |
fbb9ce95 IM |
3463 | } |
3464 | ||
a24fc60d | 3465 | static void __lock_pin_lock(struct lockdep_map *lock) |
fbb9ce95 IM |
3466 | { |
3467 | struct task_struct *curr = current; | |
a24fc60d | 3468 | int i; |
fbb9ce95 | 3469 | |
a24fc60d | 3470 | if (unlikely(!debug_locks)) |
fbb9ce95 IM |
3471 | return; |
3472 | ||
a24fc60d PZ |
3473 | for (i = 0; i < curr->lockdep_depth; i++) { |
3474 | struct held_lock *hlock = curr->held_locks + i; | |
3475 | ||
3476 | if (match_held_lock(hlock, lock)) { | |
3477 | hlock->pin_count++; | |
fbb9ce95 | 3478 | return; |
a24fc60d | 3479 | } |
fbb9ce95 IM |
3480 | } |
3481 | ||
a24fc60d | 3482 | WARN(1, "pinning an unheld lock\n"); |
fbb9ce95 IM |
3483 | } |
3484 | ||
a24fc60d | 3485 | static void __lock_unpin_lock(struct lockdep_map *lock) |
f607c668 PZ |
3486 | { |
3487 | struct task_struct *curr = current; | |
3488 | int i; | |
3489 | ||
a24fc60d PZ |
3490 | if (unlikely(!debug_locks)) |
3491 | return; | |
3492 | ||
f607c668 | 3493 | for (i = 0; i < curr->lockdep_depth; i++) { |
bb97a91e PZ |
3494 | struct held_lock *hlock = curr->held_locks + i; |
3495 | ||
a24fc60d PZ |
3496 | if (match_held_lock(hlock, lock)) { |
3497 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) | |
3498 | return; | |
3499 | ||
3500 | hlock->pin_count--; | |
3501 | return; | |
3502 | } | |
f607c668 PZ |
3503 | } |
3504 | ||
a24fc60d | 3505 | WARN(1, "unpinning an unheld lock\n"); |
f607c668 PZ |
3506 | } |
3507 | ||
fbb9ce95 IM |
3508 | /* |
3509 | * Check whether we follow the irq-flags state precisely: | |
3510 | */ | |
1d09daa5 | 3511 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3512 | { |
992860e9 IM |
3513 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3514 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3515 | if (!debug_locks) |
3516 | return; | |
3517 | ||
5f9fa8a6 IM |
3518 | if (irqs_disabled_flags(flags)) { |
3519 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3520 | printk("possible reason: unannotated irqs-off.\n"); | |
3521 | } | |
3522 | } else { | |
3523 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3524 | printk("possible reason: unannotated irqs-on.\n"); | |
3525 | } | |
3526 | } | |
fbb9ce95 IM |
3527 | |
3528 | /* | |
3529 | * We dont accurately track softirq state in e.g. | |
3530 | * hardirq contexts (such as on 4KSTACKS), so only | |
3531 | * check if not in hardirq contexts: | |
3532 | */ | |
3533 | if (!hardirq_count()) { | |
0119fee4 PZ |
3534 | if (softirq_count()) { |
3535 | /* like the above, but with softirqs */ | |
fbb9ce95 | 3536 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
0119fee4 PZ |
3537 | } else { |
3538 | /* lick the above, does it taste good? */ | |
fbb9ce95 | 3539 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
0119fee4 | 3540 | } |
fbb9ce95 IM |
3541 | } |
3542 | ||
3543 | if (!debug_locks) | |
3544 | print_irqtrace_events(current); | |
3545 | #endif | |
3546 | } | |
3547 | ||
00ef9f73 PZ |
3548 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3549 | struct lock_class_key *key, unsigned int subclass, | |
3550 | unsigned long ip) | |
64aa348e PZ |
3551 | { |
3552 | unsigned long flags; | |
3553 | ||
3554 | if (unlikely(current->lockdep_recursion)) | |
3555 | return; | |
3556 | ||
3557 | raw_local_irq_save(flags); | |
3558 | current->lockdep_recursion = 1; | |
3559 | check_flags(flags); | |
00ef9f73 | 3560 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3561 | check_chain_key(current); |
3562 | current->lockdep_recursion = 0; | |
3563 | raw_local_irq_restore(flags); | |
3564 | } | |
00ef9f73 | 3565 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3566 | |
fbb9ce95 IM |
3567 | /* |
3568 | * We are not always called with irqs disabled - do that here, | |
3569 | * and also avoid lockdep recursion: | |
3570 | */ | |
1d09daa5 | 3571 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3572 | int trylock, int read, int check, |
3573 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3574 | { |
3575 | unsigned long flags; | |
3576 | ||
3577 | if (unlikely(current->lockdep_recursion)) | |
3578 | return; | |
3579 | ||
3580 | raw_local_irq_save(flags); | |
3581 | check_flags(flags); | |
3582 | ||
3583 | current->lockdep_recursion = 1; | |
db2c4c77 | 3584 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3585 | __lock_acquire(lock, subclass, trylock, read, check, |
21199f27 | 3586 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
fbb9ce95 IM |
3587 | current->lockdep_recursion = 0; |
3588 | raw_local_irq_restore(flags); | |
3589 | } | |
fbb9ce95 IM |
3590 | EXPORT_SYMBOL_GPL(lock_acquire); |
3591 | ||
1d09daa5 | 3592 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3593 | unsigned long ip) |
fbb9ce95 IM |
3594 | { |
3595 | unsigned long flags; | |
3596 | ||
3597 | if (unlikely(current->lockdep_recursion)) | |
3598 | return; | |
3599 | ||
3600 | raw_local_irq_save(flags); | |
3601 | check_flags(flags); | |
3602 | current->lockdep_recursion = 1; | |
93135439 | 3603 | trace_lock_release(lock, ip); |
e0f56fd7 PZ |
3604 | if (__lock_release(lock, nested, ip)) |
3605 | check_chain_key(current); | |
fbb9ce95 IM |
3606 | current->lockdep_recursion = 0; |
3607 | raw_local_irq_restore(flags); | |
3608 | } | |
fbb9ce95 IM |
3609 | EXPORT_SYMBOL_GPL(lock_release); |
3610 | ||
f607c668 PZ |
3611 | int lock_is_held(struct lockdep_map *lock) |
3612 | { | |
3613 | unsigned long flags; | |
3614 | int ret = 0; | |
3615 | ||
3616 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3617 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3618 | |
3619 | raw_local_irq_save(flags); | |
3620 | check_flags(flags); | |
3621 | ||
3622 | current->lockdep_recursion = 1; | |
3623 | ret = __lock_is_held(lock); | |
3624 | current->lockdep_recursion = 0; | |
3625 | raw_local_irq_restore(flags); | |
3626 | ||
3627 | return ret; | |
3628 | } | |
3629 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3630 | ||
a24fc60d PZ |
3631 | void lock_pin_lock(struct lockdep_map *lock) |
3632 | { | |
3633 | unsigned long flags; | |
3634 | ||
3635 | if (unlikely(current->lockdep_recursion)) | |
3636 | return; | |
3637 | ||
3638 | raw_local_irq_save(flags); | |
3639 | check_flags(flags); | |
3640 | ||
3641 | current->lockdep_recursion = 1; | |
3642 | __lock_pin_lock(lock); | |
3643 | current->lockdep_recursion = 0; | |
3644 | raw_local_irq_restore(flags); | |
3645 | } | |
3646 | EXPORT_SYMBOL_GPL(lock_pin_lock); | |
3647 | ||
3648 | void lock_unpin_lock(struct lockdep_map *lock) | |
3649 | { | |
3650 | unsigned long flags; | |
3651 | ||
3652 | if (unlikely(current->lockdep_recursion)) | |
3653 | return; | |
3654 | ||
3655 | raw_local_irq_save(flags); | |
3656 | check_flags(flags); | |
3657 | ||
3658 | current->lockdep_recursion = 1; | |
3659 | __lock_unpin_lock(lock); | |
3660 | current->lockdep_recursion = 0; | |
3661 | raw_local_irq_restore(flags); | |
3662 | } | |
3663 | EXPORT_SYMBOL_GPL(lock_unpin_lock); | |
3664 | ||
cf40bd16 NP |
3665 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3666 | { | |
3667 | current->lockdep_reclaim_gfp = gfp_mask; | |
3668 | } | |
3669 | ||
3670 | void lockdep_clear_current_reclaim_state(void) | |
3671 | { | |
3672 | current->lockdep_reclaim_gfp = 0; | |
3673 | } | |
3674 | ||
f20786ff PZ |
3675 | #ifdef CONFIG_LOCK_STAT |
3676 | static int | |
3677 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3678 | unsigned long ip) | |
3679 | { | |
3680 | if (!debug_locks_off()) | |
3681 | return 0; | |
3682 | if (debug_locks_silent) | |
3683 | return 0; | |
3684 | ||
b3fbab05 PM |
3685 | printk("\n"); |
3686 | printk("=================================\n"); | |
3687 | printk("[ BUG: bad contention detected! ]\n"); | |
fbdc4b9a | 3688 | print_kernel_ident(); |
b3fbab05 | 3689 | printk("---------------------------------\n"); |
f20786ff | 3690 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3691 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3692 | print_lockdep_cache(lock); |
3693 | printk(") at:\n"); | |
3694 | print_ip_sym(ip); | |
3695 | printk("but there are no locks held!\n"); | |
3696 | printk("\nother info that might help us debug this:\n"); | |
3697 | lockdep_print_held_locks(curr); | |
3698 | ||
3699 | printk("\nstack backtrace:\n"); | |
3700 | dump_stack(); | |
3701 | ||
3702 | return 0; | |
3703 | } | |
3704 | ||
3705 | static void | |
3706 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3707 | { | |
3708 | struct task_struct *curr = current; | |
3709 | struct held_lock *hlock, *prev_hlock; | |
3710 | struct lock_class_stats *stats; | |
3711 | unsigned int depth; | |
c7e78cff | 3712 | int i, contention_point, contending_point; |
f20786ff PZ |
3713 | |
3714 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3715 | /* |
3716 | * Whee, we contended on this lock, except it seems we're not | |
3717 | * actually trying to acquire anything much at all.. | |
3718 | */ | |
f20786ff PZ |
3719 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3720 | return; | |
3721 | ||
3722 | prev_hlock = NULL; | |
3723 | for (i = depth-1; i >= 0; i--) { | |
3724 | hlock = curr->held_locks + i; | |
3725 | /* | |
3726 | * We must not cross into another context: | |
3727 | */ | |
3728 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3729 | break; | |
bb97a91e | 3730 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3731 | goto found_it; |
3732 | prev_hlock = hlock; | |
3733 | } | |
3734 | print_lock_contention_bug(curr, lock, ip); | |
3735 | return; | |
3736 | ||
3737 | found_it: | |
bb97a91e PZ |
3738 | if (hlock->instance != lock) |
3739 | return; | |
3740 | ||
3365e779 | 3741 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3742 | |
c7e78cff PZ |
3743 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3744 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3745 | lock->ip); | |
f20786ff | 3746 | |
f82b217e | 3747 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3748 | if (contention_point < LOCKSTAT_POINTS) |
3749 | stats->contention_point[contention_point]++; | |
3750 | if (contending_point < LOCKSTAT_POINTS) | |
3751 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3752 | if (lock->cpu != smp_processor_id()) |
3753 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3754 | put_lock_stats(stats); |
3755 | } | |
3756 | ||
3757 | static void | |
c7e78cff | 3758 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3759 | { |
3760 | struct task_struct *curr = current; | |
3761 | struct held_lock *hlock, *prev_hlock; | |
3762 | struct lock_class_stats *stats; | |
3763 | unsigned int depth; | |
3365e779 | 3764 | u64 now, waittime = 0; |
96645678 | 3765 | int i, cpu; |
f20786ff PZ |
3766 | |
3767 | depth = curr->lockdep_depth; | |
0119fee4 PZ |
3768 | /* |
3769 | * Yay, we acquired ownership of this lock we didn't try to | |
3770 | * acquire, how the heck did that happen? | |
3771 | */ | |
f20786ff PZ |
3772 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
3773 | return; | |
3774 | ||
3775 | prev_hlock = NULL; | |
3776 | for (i = depth-1; i >= 0; i--) { | |
3777 | hlock = curr->held_locks + i; | |
3778 | /* | |
3779 | * We must not cross into another context: | |
3780 | */ | |
3781 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3782 | break; | |
bb97a91e | 3783 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3784 | goto found_it; |
3785 | prev_hlock = hlock; | |
3786 | } | |
3787 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3788 | return; | |
3789 | ||
3790 | found_it: | |
bb97a91e PZ |
3791 | if (hlock->instance != lock) |
3792 | return; | |
3793 | ||
96645678 PZ |
3794 | cpu = smp_processor_id(); |
3795 | if (hlock->waittime_stamp) { | |
3365e779 | 3796 | now = lockstat_clock(); |
96645678 PZ |
3797 | waittime = now - hlock->waittime_stamp; |
3798 | hlock->holdtime_stamp = now; | |
3799 | } | |
f20786ff | 3800 | |
883a2a31 | 3801 | trace_lock_acquired(lock, ip); |
2062501a | 3802 | |
f82b217e | 3803 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3804 | if (waittime) { |
3805 | if (hlock->read) | |
3806 | lock_time_inc(&stats->read_waittime, waittime); | |
3807 | else | |
3808 | lock_time_inc(&stats->write_waittime, waittime); | |
3809 | } | |
3810 | if (lock->cpu != cpu) | |
3811 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3812 | put_lock_stats(stats); |
96645678 PZ |
3813 | |
3814 | lock->cpu = cpu; | |
c7e78cff | 3815 | lock->ip = ip; |
f20786ff PZ |
3816 | } |
3817 | ||
3818 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3819 | { | |
3820 | unsigned long flags; | |
3821 | ||
3822 | if (unlikely(!lock_stat)) | |
3823 | return; | |
3824 | ||
3825 | if (unlikely(current->lockdep_recursion)) | |
3826 | return; | |
3827 | ||
3828 | raw_local_irq_save(flags); | |
3829 | check_flags(flags); | |
3830 | current->lockdep_recursion = 1; | |
db2c4c77 | 3831 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3832 | __lock_contended(lock, ip); |
3833 | current->lockdep_recursion = 0; | |
3834 | raw_local_irq_restore(flags); | |
3835 | } | |
3836 | EXPORT_SYMBOL_GPL(lock_contended); | |
3837 | ||
c7e78cff | 3838 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3839 | { |
3840 | unsigned long flags; | |
3841 | ||
3842 | if (unlikely(!lock_stat)) | |
3843 | return; | |
3844 | ||
3845 | if (unlikely(current->lockdep_recursion)) | |
3846 | return; | |
3847 | ||
3848 | raw_local_irq_save(flags); | |
3849 | check_flags(flags); | |
3850 | current->lockdep_recursion = 1; | |
c7e78cff | 3851 | __lock_acquired(lock, ip); |
f20786ff PZ |
3852 | current->lockdep_recursion = 0; |
3853 | raw_local_irq_restore(flags); | |
3854 | } | |
3855 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3856 | #endif | |
3857 | ||
fbb9ce95 IM |
3858 | /* |
3859 | * Used by the testsuite, sanitize the validator state | |
3860 | * after a simulated failure: | |
3861 | */ | |
3862 | ||
3863 | void lockdep_reset(void) | |
3864 | { | |
3865 | unsigned long flags; | |
23d95a03 | 3866 | int i; |
fbb9ce95 IM |
3867 | |
3868 | raw_local_irq_save(flags); | |
3869 | current->curr_chain_key = 0; | |
3870 | current->lockdep_depth = 0; | |
3871 | current->lockdep_recursion = 0; | |
3872 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3873 | nr_hardirq_chains = 0; | |
3874 | nr_softirq_chains = 0; | |
3875 | nr_process_chains = 0; | |
3876 | debug_locks = 1; | |
23d95a03 IM |
3877 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3878 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3879 | raw_local_irq_restore(flags); |
3880 | } | |
3881 | ||
3882 | static void zap_class(struct lock_class *class) | |
3883 | { | |
3884 | int i; | |
3885 | ||
3886 | /* | |
3887 | * Remove all dependencies this lock is | |
3888 | * involved in: | |
3889 | */ | |
3890 | for (i = 0; i < nr_list_entries; i++) { | |
3891 | if (list_entries[i].class == class) | |
3892 | list_del_rcu(&list_entries[i].entry); | |
3893 | } | |
3894 | /* | |
3895 | * Unhash the class and remove it from the all_lock_classes list: | |
3896 | */ | |
3897 | list_del_rcu(&class->hash_entry); | |
3898 | list_del_rcu(&class->lock_entry); | |
3899 | ||
cee34d88 PZ |
3900 | RCU_INIT_POINTER(class->key, NULL); |
3901 | RCU_INIT_POINTER(class->name, NULL); | |
fbb9ce95 IM |
3902 | } |
3903 | ||
fabe874a | 3904 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3905 | { |
3906 | return addr >= start && addr < start + size; | |
3907 | } | |
3908 | ||
35a9393c PZ |
3909 | /* |
3910 | * Used in module.c to remove lock classes from memory that is going to be | |
3911 | * freed; and possibly re-used by other modules. | |
3912 | * | |
3913 | * We will have had one sync_sched() before getting here, so we're guaranteed | |
3914 | * nobody will look up these exact classes -- they're properly dead but still | |
3915 | * allocated. | |
3916 | */ | |
fbb9ce95 IM |
3917 | void lockdep_free_key_range(void *start, unsigned long size) |
3918 | { | |
35a9393c | 3919 | struct lock_class *class; |
fbb9ce95 IM |
3920 | struct list_head *head; |
3921 | unsigned long flags; | |
3922 | int i; | |
5a26db5b | 3923 | int locked; |
fbb9ce95 IM |
3924 | |
3925 | raw_local_irq_save(flags); | |
5a26db5b | 3926 | locked = graph_lock(); |
fbb9ce95 IM |
3927 | |
3928 | /* | |
3929 | * Unhash all classes that were created by this module: | |
3930 | */ | |
3931 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3932 | head = classhash_table + i; | |
3933 | if (list_empty(head)) | |
3934 | continue; | |
35a9393c | 3935 | list_for_each_entry_rcu(class, head, hash_entry) { |
fbb9ce95 IM |
3936 | if (within(class->key, start, size)) |
3937 | zap_class(class); | |
fabe874a AV |
3938 | else if (within(class->name, start, size)) |
3939 | zap_class(class); | |
3940 | } | |
fbb9ce95 IM |
3941 | } |
3942 | ||
5a26db5b NP |
3943 | if (locked) |
3944 | graph_unlock(); | |
fbb9ce95 | 3945 | raw_local_irq_restore(flags); |
35a9393c PZ |
3946 | |
3947 | /* | |
3948 | * Wait for any possible iterators from look_up_lock_class() to pass | |
3949 | * before continuing to free the memory they refer to. | |
3950 | * | |
3951 | * sync_sched() is sufficient because the read-side is IRQ disable. | |
3952 | */ | |
3953 | synchronize_sched(); | |
3954 | ||
3955 | /* | |
3956 | * XXX at this point we could return the resources to the pool; | |
3957 | * instead we leak them. We would need to change to bitmap allocators | |
3958 | * instead of the linear allocators we have now. | |
3959 | */ | |
fbb9ce95 IM |
3960 | } |
3961 | ||
3962 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3963 | { | |
35a9393c | 3964 | struct lock_class *class; |
fbb9ce95 IM |
3965 | struct list_head *head; |
3966 | unsigned long flags; | |
3967 | int i, j; | |
5a26db5b | 3968 | int locked; |
fbb9ce95 IM |
3969 | |
3970 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3971 | |
3972 | /* | |
d6d897ce IM |
3973 | * Remove all classes this lock might have: |
3974 | */ | |
3975 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3976 | /* | |
3977 | * If the class exists we look it up and zap it: | |
3978 | */ | |
3979 | class = look_up_lock_class(lock, j); | |
3980 | if (class) | |
3981 | zap_class(class); | |
3982 | } | |
3983 | /* | |
3984 | * Debug check: in the end all mapped classes should | |
3985 | * be gone. | |
fbb9ce95 | 3986 | */ |
5a26db5b | 3987 | locked = graph_lock(); |
fbb9ce95 IM |
3988 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3989 | head = classhash_table + i; | |
3990 | if (list_empty(head)) | |
3991 | continue; | |
35a9393c | 3992 | list_for_each_entry_rcu(class, head, hash_entry) { |
62016250 HM |
3993 | int match = 0; |
3994 | ||
3995 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
3996 | match |= class == lock->class_cache[j]; | |
3997 | ||
3998 | if (unlikely(match)) { | |
0119fee4 PZ |
3999 | if (debug_locks_off_graph_unlock()) { |
4000 | /* | |
4001 | * We all just reset everything, how did it match? | |
4002 | */ | |
74c383f1 | 4003 | WARN_ON(1); |
0119fee4 | 4004 | } |
d6d897ce | 4005 | goto out_restore; |
fbb9ce95 IM |
4006 | } |
4007 | } | |
4008 | } | |
5a26db5b NP |
4009 | if (locked) |
4010 | graph_unlock(); | |
d6d897ce IM |
4011 | |
4012 | out_restore: | |
fbb9ce95 IM |
4013 | raw_local_irq_restore(flags); |
4014 | } | |
4015 | ||
1499993c | 4016 | void lockdep_init(void) |
fbb9ce95 IM |
4017 | { |
4018 | int i; | |
4019 | ||
4020 | /* | |
4021 | * Some architectures have their own start_kernel() | |
4022 | * code which calls lockdep_init(), while we also | |
4023 | * call lockdep_init() from the start_kernel() itself, | |
4024 | * and we want to initialize the hashes only once: | |
4025 | */ | |
4026 | if (lockdep_initialized) | |
4027 | return; | |
4028 | ||
4029 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
4030 | INIT_LIST_HEAD(classhash_table + i); | |
4031 | ||
4032 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
4033 | INIT_LIST_HEAD(chainhash_table + i); | |
4034 | ||
4035 | lockdep_initialized = 1; | |
4036 | } | |
4037 | ||
4038 | void __init lockdep_info(void) | |
4039 | { | |
4040 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
4041 | ||
b0788caf | 4042 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
4043 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
4044 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 4045 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
4046 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
4047 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
4048 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
4049 | ||
4050 | printk(" memory used by lock dependency info: %lu kB\n", | |
4051 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
4052 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
4053 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
4054 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 4055 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 4056 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 4057 | + sizeof(struct circular_queue) |
4dd861d6 | 4058 | #endif |
90629209 | 4059 | ) / 1024 |
4dd861d6 | 4060 | ); |
fbb9ce95 IM |
4061 | |
4062 | printk(" per task-struct memory footprint: %lu bytes\n", | |
4063 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
4064 | ||
4065 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 | 4066 | if (lockdep_init_error) { |
92ae1837 | 4067 | printk("WARNING: lockdep init error: lock '%s' was acquired before lockdep_init().\n", lock_init_error); |
c71063c9 JB |
4068 | printk("Call stack leading to lockdep invocation was:\n"); |
4069 | print_stack_trace(&lockdep_init_trace, 0); | |
4070 | } | |
fbb9ce95 IM |
4071 | #endif |
4072 | } | |
4073 | ||
fbb9ce95 IM |
4074 | static void |
4075 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 4076 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
4077 | { |
4078 | if (!debug_locks_off()) | |
4079 | return; | |
4080 | if (debug_locks_silent) | |
4081 | return; | |
4082 | ||
b3fbab05 PM |
4083 | printk("\n"); |
4084 | printk("=========================\n"); | |
4085 | printk("[ BUG: held lock freed! ]\n"); | |
fbdc4b9a | 4086 | print_kernel_ident(); |
b3fbab05 | 4087 | printk("-------------------------\n"); |
fbb9ce95 | 4088 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 4089 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 4090 | print_lock(hlock); |
fbb9ce95 IM |
4091 | lockdep_print_held_locks(curr); |
4092 | ||
4093 | printk("\nstack backtrace:\n"); | |
4094 | dump_stack(); | |
4095 | } | |
4096 | ||
54561783 ON |
4097 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
4098 | const void* lock_from, unsigned long lock_len) | |
4099 | { | |
4100 | return lock_from + lock_len <= mem_from || | |
4101 | mem_from + mem_len <= lock_from; | |
4102 | } | |
4103 | ||
fbb9ce95 IM |
4104 | /* |
4105 | * Called when kernel memory is freed (or unmapped), or if a lock | |
4106 | * is destroyed or reinitialized - this code checks whether there is | |
4107 | * any held lock in the memory range of <from> to <to>: | |
4108 | */ | |
4109 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
4110 | { | |
fbb9ce95 IM |
4111 | struct task_struct *curr = current; |
4112 | struct held_lock *hlock; | |
4113 | unsigned long flags; | |
4114 | int i; | |
4115 | ||
4116 | if (unlikely(!debug_locks)) | |
4117 | return; | |
4118 | ||
4119 | local_irq_save(flags); | |
4120 | for (i = 0; i < curr->lockdep_depth; i++) { | |
4121 | hlock = curr->held_locks + i; | |
4122 | ||
54561783 ON |
4123 | if (not_in_range(mem_from, mem_len, hlock->instance, |
4124 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
4125 | continue; |
4126 | ||
54561783 | 4127 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
4128 | break; |
4129 | } | |
4130 | local_irq_restore(flags); | |
4131 | } | |
ed07536e | 4132 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 | 4133 | |
1b1d2fb4 | 4134 | static void print_held_locks_bug(void) |
fbb9ce95 IM |
4135 | { |
4136 | if (!debug_locks_off()) | |
4137 | return; | |
4138 | if (debug_locks_silent) | |
4139 | return; | |
4140 | ||
b3fbab05 PM |
4141 | printk("\n"); |
4142 | printk("=====================================\n"); | |
1b1d2fb4 CC |
4143 | printk("[ BUG: %s/%d still has locks held! ]\n", |
4144 | current->comm, task_pid_nr(current)); | |
fbdc4b9a | 4145 | print_kernel_ident(); |
b3fbab05 | 4146 | printk("-------------------------------------\n"); |
1b1d2fb4 | 4147 | lockdep_print_held_locks(current); |
fbb9ce95 IM |
4148 | printk("\nstack backtrace:\n"); |
4149 | dump_stack(); | |
4150 | } | |
4151 | ||
1b1d2fb4 | 4152 | void debug_check_no_locks_held(void) |
fbb9ce95 | 4153 | { |
1b1d2fb4 CC |
4154 | if (unlikely(current->lockdep_depth > 0)) |
4155 | print_held_locks_bug(); | |
fbb9ce95 | 4156 | } |
1b1d2fb4 | 4157 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
fbb9ce95 | 4158 | |
8dce7a9a | 4159 | #ifdef __KERNEL__ |
fbb9ce95 IM |
4160 | void debug_show_all_locks(void) |
4161 | { | |
4162 | struct task_struct *g, *p; | |
4163 | int count = 10; | |
4164 | int unlock = 1; | |
4165 | ||
9c35dd7f JP |
4166 | if (unlikely(!debug_locks)) { |
4167 | printk("INFO: lockdep is turned off.\n"); | |
4168 | return; | |
4169 | } | |
fbb9ce95 IM |
4170 | printk("\nShowing all locks held in the system:\n"); |
4171 | ||
4172 | /* | |
4173 | * Here we try to get the tasklist_lock as hard as possible, | |
4174 | * if not successful after 2 seconds we ignore it (but keep | |
4175 | * trying). This is to enable a debug printout even if a | |
4176 | * tasklist_lock-holding task deadlocks or crashes. | |
4177 | */ | |
4178 | retry: | |
4179 | if (!read_trylock(&tasklist_lock)) { | |
4180 | if (count == 10) | |
4181 | printk("hm, tasklist_lock locked, retrying... "); | |
4182 | if (count) { | |
4183 | count--; | |
4184 | printk(" #%d", 10-count); | |
4185 | mdelay(200); | |
4186 | goto retry; | |
4187 | } | |
4188 | printk(" ignoring it.\n"); | |
4189 | unlock = 0; | |
46fec7ac | 4190 | } else { |
4191 | if (count != 10) | |
4192 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 4193 | } |
fbb9ce95 IM |
4194 | |
4195 | do_each_thread(g, p) { | |
85684873 IM |
4196 | /* |
4197 | * It's not reliable to print a task's held locks | |
4198 | * if it's not sleeping (or if it's not the current | |
4199 | * task): | |
4200 | */ | |
4201 | if (p->state == TASK_RUNNING && p != current) | |
4202 | continue; | |
fbb9ce95 IM |
4203 | if (p->lockdep_depth) |
4204 | lockdep_print_held_locks(p); | |
4205 | if (!unlock) | |
4206 | if (read_trylock(&tasklist_lock)) | |
4207 | unlock = 1; | |
4208 | } while_each_thread(g, p); | |
4209 | ||
4210 | printk("\n"); | |
4211 | printk("=============================================\n\n"); | |
4212 | ||
4213 | if (unlock) | |
4214 | read_unlock(&tasklist_lock); | |
4215 | } | |
fbb9ce95 | 4216 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
8dce7a9a | 4217 | #endif |
fbb9ce95 | 4218 | |
82a1fcb9 IM |
4219 | /* |
4220 | * Careful: only use this function if you are sure that | |
4221 | * the task cannot run in parallel! | |
4222 | */ | |
f1b499f0 | 4223 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 4224 | { |
9c35dd7f JP |
4225 | if (unlikely(!debug_locks)) { |
4226 | printk("INFO: lockdep is turned off.\n"); | |
4227 | return; | |
4228 | } | |
fbb9ce95 IM |
4229 | lockdep_print_held_locks(task); |
4230 | } | |
fbb9ce95 | 4231 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 | 4232 | |
722a9f92 | 4233 | asmlinkage __visible void lockdep_sys_exit(void) |
b351d164 PZ |
4234 | { |
4235 | struct task_struct *curr = current; | |
4236 | ||
4237 | if (unlikely(curr->lockdep_depth)) { | |
4238 | if (!debug_locks_off()) | |
4239 | return; | |
b3fbab05 PM |
4240 | printk("\n"); |
4241 | printk("================================================\n"); | |
4242 | printk("[ BUG: lock held when returning to user space! ]\n"); | |
fbdc4b9a | 4243 | print_kernel_ident(); |
b3fbab05 | 4244 | printk("------------------------------------------------\n"); |
b351d164 PZ |
4245 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4246 | curr->comm, curr->pid); | |
4247 | lockdep_print_held_locks(curr); | |
4248 | } | |
4249 | } | |
0632eb3d | 4250 | |
b3fbab05 | 4251 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4252 | { |
4253 | struct task_struct *curr = current; | |
4254 | ||
2b3fc35f | 4255 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4256 | if (!debug_locks_off()) |
4257 | return; | |
2b3fc35f LJ |
4258 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4259 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 PM |
4260 | printk("\n"); |
4261 | printk("===============================\n"); | |
4262 | printk("[ INFO: suspicious RCU usage. ]\n"); | |
fbdc4b9a | 4263 | print_kernel_ident(); |
b3fbab05 PM |
4264 | printk("-------------------------------\n"); |
4265 | printk("%s:%d %s!\n", file, line, s); | |
0632eb3d | 4266 | printk("\nother info that might help us debug this:\n\n"); |
c5fdcec9 PM |
4267 | printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n", |
4268 | !rcu_lockdep_current_cpu_online() | |
4269 | ? "RCU used illegally from offline CPU!\n" | |
5c173eb8 | 4270 | : !rcu_is_watching() |
c5fdcec9 PM |
4271 | ? "RCU used illegally from idle CPU!\n" |
4272 | : "", | |
4273 | rcu_scheduler_active, debug_locks); | |
0464e937 FW |
4274 | |
4275 | /* | |
4276 | * If a CPU is in the RCU-free window in idle (ie: in the section | |
4277 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU | |
4278 | * considers that CPU to be in an "extended quiescent state", | |
4279 | * which means that RCU will be completely ignoring that CPU. | |
4280 | * Therefore, rcu_read_lock() and friends have absolutely no | |
4281 | * effect on a CPU running in that state. In other words, even if | |
4282 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well | |
4283 | * delete data structures out from under it. RCU really has no | |
4284 | * choice here: we need to keep an RCU-free window in idle where | |
4285 | * the CPU may possibly enter into low power mode. This way we can | |
4286 | * notice an extended quiescent state to other CPUs that started a grace | |
4287 | * period. Otherwise we would delay any grace period as long as we run | |
4288 | * in the idle task. | |
4289 | * | |
4290 | * So complain bitterly if someone does call rcu_read_lock(), | |
4291 | * rcu_read_lock_bh() and so on from extended quiescent states. | |
4292 | */ | |
5c173eb8 | 4293 | if (!rcu_is_watching()) |
0464e937 FW |
4294 | printk("RCU used illegally from extended quiescent state!\n"); |
4295 | ||
0632eb3d PM |
4296 | lockdep_print_held_locks(curr); |
4297 | printk("\nstack backtrace:\n"); | |
4298 | dump_stack(); | |
4299 | } | |
b3fbab05 | 4300 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |