Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
af012961 | 47 | |
fbb9ce95 IM |
48 | #include <asm/sections.h> |
49 | ||
50 | #include "lockdep_internals.h" | |
51 | ||
a8d154b0 | 52 | #define CREATE_TRACE_POINTS |
67178767 | 53 | #include <trace/events/lock.h> |
a8d154b0 | 54 | |
f20786ff PZ |
55 | #ifdef CONFIG_PROVE_LOCKING |
56 | int prove_locking = 1; | |
57 | module_param(prove_locking, int, 0644); | |
58 | #else | |
59 | #define prove_locking 0 | |
60 | #endif | |
61 | ||
62 | #ifdef CONFIG_LOCK_STAT | |
63 | int lock_stat = 1; | |
64 | module_param(lock_stat, int, 0644); | |
65 | #else | |
66 | #define lock_stat 0 | |
67 | #endif | |
68 | ||
fbb9ce95 | 69 | /* |
74c383f1 IM |
70 | * lockdep_lock: protects the lockdep graph, the hashes and the |
71 | * class/list/hash allocators. | |
fbb9ce95 IM |
72 | * |
73 | * This is one of the rare exceptions where it's justified | |
74 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 75 | * code to recurse back into the lockdep code... |
fbb9ce95 | 76 | */ |
edc35bd7 | 77 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
78 | |
79 | static int graph_lock(void) | |
80 | { | |
0199c4e6 | 81 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
82 | /* |
83 | * Make sure that if another CPU detected a bug while | |
84 | * walking the graph we dont change it (while the other | |
85 | * CPU is busy printing out stuff with the graph lock | |
86 | * dropped already) | |
87 | */ | |
88 | if (!debug_locks) { | |
0199c4e6 | 89 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
90 | return 0; |
91 | } | |
bb065afb SR |
92 | /* prevent any recursions within lockdep from causing deadlocks */ |
93 | current->lockdep_recursion++; | |
74c383f1 IM |
94 | return 1; |
95 | } | |
96 | ||
97 | static inline int graph_unlock(void) | |
98 | { | |
0199c4e6 | 99 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) |
381a2292 JP |
100 | return DEBUG_LOCKS_WARN_ON(1); |
101 | ||
bb065afb | 102 | current->lockdep_recursion--; |
0199c4e6 | 103 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
104 | return 0; |
105 | } | |
106 | ||
107 | /* | |
108 | * Turn lock debugging off and return with 0 if it was off already, | |
109 | * and also release the graph lock: | |
110 | */ | |
111 | static inline int debug_locks_off_graph_unlock(void) | |
112 | { | |
113 | int ret = debug_locks_off(); | |
114 | ||
0199c4e6 | 115 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
116 | |
117 | return ret; | |
118 | } | |
fbb9ce95 IM |
119 | |
120 | static int lockdep_initialized; | |
121 | ||
122 | unsigned long nr_list_entries; | |
af012961 | 123 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 124 | |
fbb9ce95 IM |
125 | /* |
126 | * All data structures here are protected by the global debug_lock. | |
127 | * | |
128 | * Mutex key structs only get allocated, once during bootup, and never | |
129 | * get freed - this significantly simplifies the debugging code. | |
130 | */ | |
131 | unsigned long nr_lock_classes; | |
132 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
133 | ||
f82b217e DJ |
134 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
135 | { | |
136 | if (!hlock->class_idx) { | |
137 | DEBUG_LOCKS_WARN_ON(1); | |
138 | return NULL; | |
139 | } | |
140 | return lock_classes + hlock->class_idx - 1; | |
141 | } | |
142 | ||
f20786ff | 143 | #ifdef CONFIG_LOCK_STAT |
1871e52c TH |
144 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
145 | cpu_lock_stats); | |
f20786ff | 146 | |
3365e779 PZ |
147 | static inline u64 lockstat_clock(void) |
148 | { | |
c676329a | 149 | return local_clock(); |
3365e779 PZ |
150 | } |
151 | ||
c7e78cff | 152 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
153 | { |
154 | int i; | |
155 | ||
c7e78cff PZ |
156 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
157 | if (points[i] == 0) { | |
158 | points[i] = ip; | |
f20786ff PZ |
159 | break; |
160 | } | |
c7e78cff | 161 | if (points[i] == ip) |
f20786ff PZ |
162 | break; |
163 | } | |
164 | ||
165 | return i; | |
166 | } | |
167 | ||
3365e779 | 168 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
169 | { |
170 | if (time > lt->max) | |
171 | lt->max = time; | |
172 | ||
109d71c6 | 173 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
174 | lt->min = time; |
175 | ||
176 | lt->total += time; | |
177 | lt->nr++; | |
178 | } | |
179 | ||
c46261de PZ |
180 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
181 | { | |
109d71c6 FR |
182 | if (!src->nr) |
183 | return; | |
184 | ||
185 | if (src->max > dst->max) | |
186 | dst->max = src->max; | |
187 | ||
188 | if (src->min < dst->min || !dst->nr) | |
189 | dst->min = src->min; | |
190 | ||
c46261de PZ |
191 | dst->total += src->total; |
192 | dst->nr += src->nr; | |
193 | } | |
194 | ||
195 | struct lock_class_stats lock_stats(struct lock_class *class) | |
196 | { | |
197 | struct lock_class_stats stats; | |
198 | int cpu, i; | |
199 | ||
200 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
201 | for_each_possible_cpu(cpu) { | |
202 | struct lock_class_stats *pcs = | |
1871e52c | 203 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
204 | |
205 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
206 | stats.contention_point[i] += pcs->contention_point[i]; | |
207 | ||
c7e78cff PZ |
208 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
209 | stats.contending_point[i] += pcs->contending_point[i]; | |
210 | ||
c46261de PZ |
211 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
212 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
213 | ||
214 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
215 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
216 | |
217 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
218 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
219 | } |
220 | ||
221 | return stats; | |
222 | } | |
223 | ||
224 | void clear_lock_stats(struct lock_class *class) | |
225 | { | |
226 | int cpu; | |
227 | ||
228 | for_each_possible_cpu(cpu) { | |
229 | struct lock_class_stats *cpu_stats = | |
1871e52c | 230 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
231 | |
232 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
233 | } | |
234 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 235 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
236 | } |
237 | ||
f20786ff PZ |
238 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
239 | { | |
1871e52c | 240 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
241 | } |
242 | ||
243 | static void put_lock_stats(struct lock_class_stats *stats) | |
244 | { | |
1871e52c | 245 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
246 | } |
247 | ||
248 | static void lock_release_holdtime(struct held_lock *hlock) | |
249 | { | |
250 | struct lock_class_stats *stats; | |
3365e779 | 251 | u64 holdtime; |
f20786ff PZ |
252 | |
253 | if (!lock_stat) | |
254 | return; | |
255 | ||
3365e779 | 256 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 257 | |
f82b217e | 258 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
259 | if (hlock->read) |
260 | lock_time_inc(&stats->read_holdtime, holdtime); | |
261 | else | |
262 | lock_time_inc(&stats->write_holdtime, holdtime); | |
263 | put_lock_stats(stats); | |
264 | } | |
265 | #else | |
266 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
267 | { | |
268 | } | |
269 | #endif | |
270 | ||
fbb9ce95 IM |
271 | /* |
272 | * We keep a global list of all lock classes. The list only grows, | |
273 | * never shrinks. The list is only accessed with the lockdep | |
274 | * spinlock lock held. | |
275 | */ | |
276 | LIST_HEAD(all_lock_classes); | |
277 | ||
278 | /* | |
279 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
280 | */ | |
281 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
282 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 283 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
284 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
285 | ||
286 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
287 | ||
fbb9ce95 IM |
288 | /* |
289 | * We put the lock dependency chains into a hash-table as well, to cache | |
290 | * their existence: | |
291 | */ | |
292 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
293 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 294 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
295 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
296 | ||
297 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
298 | ||
299 | /* | |
300 | * The hash key of the lock dependency chains is a hash itself too: | |
301 | * it's a hash of all locks taken up to that lock, including that lock. | |
302 | * It's a 64-bit hash, because it's important for the keys to be | |
303 | * unique. | |
304 | */ | |
305 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
306 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
307 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
308 | (key2)) |
309 | ||
1d09daa5 | 310 | void lockdep_off(void) |
fbb9ce95 IM |
311 | { |
312 | current->lockdep_recursion++; | |
313 | } | |
fbb9ce95 IM |
314 | EXPORT_SYMBOL(lockdep_off); |
315 | ||
1d09daa5 | 316 | void lockdep_on(void) |
fbb9ce95 IM |
317 | { |
318 | current->lockdep_recursion--; | |
319 | } | |
fbb9ce95 IM |
320 | EXPORT_SYMBOL(lockdep_on); |
321 | ||
fbb9ce95 IM |
322 | /* |
323 | * Debugging switches: | |
324 | */ | |
325 | ||
326 | #define VERBOSE 0 | |
33e94e96 | 327 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
328 | |
329 | #if VERBOSE | |
330 | # define HARDIRQ_VERBOSE 1 | |
331 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 332 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
333 | #else |
334 | # define HARDIRQ_VERBOSE 0 | |
335 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 336 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
337 | #endif |
338 | ||
cf40bd16 | 339 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
340 | /* |
341 | * Quick filtering for interesting events: | |
342 | */ | |
343 | static int class_filter(struct lock_class *class) | |
344 | { | |
f9829cce AK |
345 | #if 0 |
346 | /* Example */ | |
fbb9ce95 | 347 | if (class->name_version == 1 && |
f9829cce | 348 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
349 | return 1; |
350 | if (class->name_version == 1 && | |
f9829cce | 351 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 352 | return 1; |
f9829cce | 353 | #endif |
a6640897 IM |
354 | /* Filter everything else. 1 would be to allow everything else */ |
355 | return 0; | |
fbb9ce95 IM |
356 | } |
357 | #endif | |
358 | ||
359 | static int verbose(struct lock_class *class) | |
360 | { | |
361 | #if VERBOSE | |
362 | return class_filter(class); | |
363 | #endif | |
364 | return 0; | |
365 | } | |
366 | ||
fbb9ce95 IM |
367 | /* |
368 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 369 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
370 | */ |
371 | unsigned long nr_stack_trace_entries; | |
372 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
373 | ||
374 | static int save_trace(struct stack_trace *trace) | |
375 | { | |
376 | trace->nr_entries = 0; | |
377 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
378 | trace->entries = stack_trace + nr_stack_trace_entries; | |
379 | ||
5a1b3999 | 380 | trace->skip = 3; |
5a1b3999 | 381 | |
ab1b6f03 | 382 | save_stack_trace(trace); |
fbb9ce95 | 383 | |
4f84f433 PZ |
384 | /* |
385 | * Some daft arches put -1 at the end to indicate its a full trace. | |
386 | * | |
387 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
388 | * complete trace that maxes out the entries provided will be reported | |
389 | * as incomplete, friggin useless </rant> | |
390 | */ | |
ea5b41f9 LT |
391 | if (trace->nr_entries != 0 && |
392 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
393 | trace->nr_entries--; |
394 | ||
fbb9ce95 IM |
395 | trace->max_entries = trace->nr_entries; |
396 | ||
397 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 398 | |
4f84f433 | 399 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
400 | if (!debug_locks_off_graph_unlock()) |
401 | return 0; | |
402 | ||
403 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
404 | printk("turning off the locking correctness validator.\n"); | |
405 | dump_stack(); | |
406 | ||
fbb9ce95 IM |
407 | return 0; |
408 | } | |
409 | ||
410 | return 1; | |
411 | } | |
412 | ||
413 | unsigned int nr_hardirq_chains; | |
414 | unsigned int nr_softirq_chains; | |
415 | unsigned int nr_process_chains; | |
416 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
417 | |
418 | #ifdef CONFIG_DEBUG_LOCKDEP | |
419 | /* | |
420 | * We cannot printk in early bootup code. Not even early_printk() | |
421 | * might work. So we mark any initialization errors and printk | |
422 | * about it later on, in lockdep_info(). | |
423 | */ | |
424 | static int lockdep_init_error; | |
c71063c9 JB |
425 | static unsigned long lockdep_init_trace_data[20]; |
426 | static struct stack_trace lockdep_init_trace = { | |
427 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
428 | .entries = lockdep_init_trace_data, | |
429 | }; | |
fbb9ce95 IM |
430 | |
431 | /* | |
432 | * Various lockdep statistics: | |
433 | */ | |
bd6d29c2 | 434 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
435 | #endif |
436 | ||
437 | /* | |
438 | * Locking printouts: | |
439 | */ | |
440 | ||
fabe9c42 | 441 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
442 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
443 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
444 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
445 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 446 | |
fbb9ce95 IM |
447 | static const char *usage_str[] = |
448 | { | |
fabe9c42 PZ |
449 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
450 | #include "lockdep_states.h" | |
451 | #undef LOCKDEP_STATE | |
452 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
453 | }; |
454 | ||
455 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
456 | { | |
ffb45122 | 457 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
458 | } |
459 | ||
3ff176ca | 460 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 461 | { |
3ff176ca PZ |
462 | return 1UL << bit; |
463 | } | |
fbb9ce95 | 464 | |
3ff176ca PZ |
465 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
466 | { | |
467 | char c = '.'; | |
468 | ||
469 | if (class->usage_mask & lock_flag(bit + 2)) | |
470 | c = '+'; | |
471 | if (class->usage_mask & lock_flag(bit)) { | |
472 | c = '-'; | |
473 | if (class->usage_mask & lock_flag(bit + 2)) | |
474 | c = '?'; | |
fbb9ce95 IM |
475 | } |
476 | ||
3ff176ca PZ |
477 | return c; |
478 | } | |
cf40bd16 | 479 | |
f510b233 | 480 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 481 | { |
f510b233 | 482 | int i = 0; |
cf40bd16 | 483 | |
f510b233 PZ |
484 | #define LOCKDEP_STATE(__STATE) \ |
485 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
486 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
487 | #include "lockdep_states.h" | |
488 | #undef LOCKDEP_STATE | |
489 | ||
490 | usage[i] = '\0'; | |
fbb9ce95 IM |
491 | } |
492 | ||
3003eba3 SR |
493 | static int __print_lock_name(struct lock_class *class) |
494 | { | |
495 | char str[KSYM_NAME_LEN]; | |
496 | const char *name; | |
497 | ||
498 | name = class->name; | |
499 | if (!name) | |
500 | name = __get_key_name(class->key, str); | |
501 | ||
502 | return printk("%s", name); | |
503 | } | |
504 | ||
fbb9ce95 IM |
505 | static void print_lock_name(struct lock_class *class) |
506 | { | |
f510b233 | 507 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
508 | const char *name; |
509 | ||
f510b233 | 510 | get_usage_chars(class, usage); |
fbb9ce95 IM |
511 | |
512 | name = class->name; | |
513 | if (!name) { | |
514 | name = __get_key_name(class->key, str); | |
515 | printk(" (%s", name); | |
516 | } else { | |
517 | printk(" (%s", name); | |
518 | if (class->name_version > 1) | |
519 | printk("#%d", class->name_version); | |
520 | if (class->subclass) | |
521 | printk("/%d", class->subclass); | |
522 | } | |
f510b233 | 523 | printk("){%s}", usage); |
fbb9ce95 IM |
524 | } |
525 | ||
526 | static void print_lockdep_cache(struct lockdep_map *lock) | |
527 | { | |
528 | const char *name; | |
9281acea | 529 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
530 | |
531 | name = lock->name; | |
532 | if (!name) | |
533 | name = __get_key_name(lock->key->subkeys, str); | |
534 | ||
535 | printk("%s", name); | |
536 | } | |
537 | ||
538 | static void print_lock(struct held_lock *hlock) | |
539 | { | |
f82b217e | 540 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
541 | printk(", at: "); |
542 | print_ip_sym(hlock->acquire_ip); | |
543 | } | |
544 | ||
545 | static void lockdep_print_held_locks(struct task_struct *curr) | |
546 | { | |
547 | int i, depth = curr->lockdep_depth; | |
548 | ||
549 | if (!depth) { | |
ba25f9dc | 550 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
551 | return; |
552 | } | |
553 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 554 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
555 | |
556 | for (i = 0; i < depth; i++) { | |
557 | printk(" #%d: ", i); | |
558 | print_lock(curr->held_locks + i); | |
559 | } | |
560 | } | |
fbb9ce95 | 561 | |
8e18257d PZ |
562 | static void print_kernel_version(void) |
563 | { | |
564 | printk("%s %.*s\n", init_utsname()->release, | |
565 | (int)strcspn(init_utsname()->version, " "), | |
566 | init_utsname()->version); | |
567 | } | |
568 | ||
569 | static int very_verbose(struct lock_class *class) | |
570 | { | |
571 | #if VERY_VERBOSE | |
572 | return class_filter(class); | |
573 | #endif | |
574 | return 0; | |
575 | } | |
576 | ||
fbb9ce95 | 577 | /* |
8e18257d | 578 | * Is this the address of a static object: |
fbb9ce95 | 579 | */ |
8e18257d | 580 | static int static_obj(void *obj) |
fbb9ce95 | 581 | { |
8e18257d PZ |
582 | unsigned long start = (unsigned long) &_stext, |
583 | end = (unsigned long) &_end, | |
584 | addr = (unsigned long) obj; | |
8e18257d | 585 | |
fbb9ce95 | 586 | /* |
8e18257d | 587 | * static variable? |
fbb9ce95 | 588 | */ |
8e18257d PZ |
589 | if ((addr >= start) && (addr < end)) |
590 | return 1; | |
fbb9ce95 | 591 | |
2a9ad18d MF |
592 | if (arch_is_kernel_data(addr)) |
593 | return 1; | |
594 | ||
fbb9ce95 | 595 | /* |
10fad5e4 | 596 | * in-kernel percpu var? |
fbb9ce95 | 597 | */ |
10fad5e4 TH |
598 | if (is_kernel_percpu_address(addr)) |
599 | return 1; | |
fbb9ce95 | 600 | |
8e18257d | 601 | /* |
10fad5e4 | 602 | * module static or percpu var? |
8e18257d | 603 | */ |
10fad5e4 | 604 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a DJ |
605 | } |
606 | ||
fbb9ce95 | 607 | /* |
8e18257d PZ |
608 | * To make lock name printouts unique, we calculate a unique |
609 | * class->name_version generation counter: | |
fbb9ce95 | 610 | */ |
8e18257d | 611 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 612 | { |
8e18257d PZ |
613 | struct lock_class *class; |
614 | int count = 0; | |
fbb9ce95 | 615 | |
8e18257d | 616 | if (!new_class->name) |
fbb9ce95 IM |
617 | return 0; |
618 | ||
8e18257d PZ |
619 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
620 | if (new_class->key - new_class->subclass == class->key) | |
621 | return class->name_version; | |
622 | if (class->name && !strcmp(class->name, new_class->name)) | |
623 | count = max(count, class->name_version); | |
624 | } | |
fbb9ce95 | 625 | |
8e18257d | 626 | return count + 1; |
fbb9ce95 IM |
627 | } |
628 | ||
8e18257d PZ |
629 | /* |
630 | * Register a lock's class in the hash-table, if the class is not present | |
631 | * yet. Otherwise we look it up. We cache the result in the lock object | |
632 | * itself, so actual lookup of the hash should be once per lock object. | |
633 | */ | |
634 | static inline struct lock_class * | |
635 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 636 | { |
8e18257d PZ |
637 | struct lockdep_subclass_key *key; |
638 | struct list_head *hash_head; | |
639 | struct lock_class *class; | |
fbb9ce95 | 640 | |
8e18257d PZ |
641 | #ifdef CONFIG_DEBUG_LOCKDEP |
642 | /* | |
643 | * If the architecture calls into lockdep before initializing | |
644 | * the hashes then we'll warn about it later. (we cannot printk | |
645 | * right now) | |
646 | */ | |
647 | if (unlikely(!lockdep_initialized)) { | |
648 | lockdep_init(); | |
649 | lockdep_init_error = 1; | |
c71063c9 | 650 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
651 | } |
652 | #endif | |
fbb9ce95 | 653 | |
4ba053c0 HM |
654 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
655 | debug_locks_off(); | |
656 | printk(KERN_ERR | |
657 | "BUG: looking up invalid subclass: %u\n", subclass); | |
658 | printk(KERN_ERR | |
659 | "turning off the locking correctness validator.\n"); | |
660 | dump_stack(); | |
661 | return NULL; | |
662 | } | |
663 | ||
8e18257d PZ |
664 | /* |
665 | * Static locks do not have their class-keys yet - for them the key | |
666 | * is the lock object itself: | |
667 | */ | |
668 | if (unlikely(!lock->key)) | |
669 | lock->key = (void *)lock; | |
fbb9ce95 | 670 | |
8e18257d PZ |
671 | /* |
672 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
673 | * lock_class_key variable is passed in through the mutex_init() | |
674 | * (or spin_lock_init()) call - which acts as the key. For static | |
675 | * locks we use the lock object itself as the key. | |
676 | */ | |
4b32d0a4 PZ |
677 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
678 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 679 | |
8e18257d | 680 | key = lock->key->subkeys + subclass; |
ca268c69 | 681 | |
8e18257d | 682 | hash_head = classhashentry(key); |
74c383f1 | 683 | |
8e18257d PZ |
684 | /* |
685 | * We can walk the hash lockfree, because the hash only | |
686 | * grows, and we are careful when adding entries to the end: | |
687 | */ | |
4b32d0a4 PZ |
688 | list_for_each_entry(class, hash_head, hash_entry) { |
689 | if (class->key == key) { | |
690 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 691 | return class; |
4b32d0a4 PZ |
692 | } |
693 | } | |
fbb9ce95 | 694 | |
8e18257d | 695 | return NULL; |
fbb9ce95 IM |
696 | } |
697 | ||
698 | /* | |
8e18257d PZ |
699 | * Register a lock's class in the hash-table, if the class is not present |
700 | * yet. Otherwise we look it up. We cache the result in the lock object | |
701 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 702 | */ |
8e18257d PZ |
703 | static inline struct lock_class * |
704 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 705 | { |
8e18257d PZ |
706 | struct lockdep_subclass_key *key; |
707 | struct list_head *hash_head; | |
708 | struct lock_class *class; | |
709 | unsigned long flags; | |
710 | ||
711 | class = look_up_lock_class(lock, subclass); | |
712 | if (likely(class)) | |
713 | return class; | |
714 | ||
715 | /* | |
716 | * Debug-check: all keys must be persistent! | |
717 | */ | |
718 | if (!static_obj(lock->key)) { | |
719 | debug_locks_off(); | |
720 | printk("INFO: trying to register non-static key.\n"); | |
721 | printk("the code is fine but needs lockdep annotation.\n"); | |
722 | printk("turning off the locking correctness validator.\n"); | |
723 | dump_stack(); | |
724 | ||
725 | return NULL; | |
726 | } | |
727 | ||
728 | key = lock->key->subkeys + subclass; | |
729 | hash_head = classhashentry(key); | |
730 | ||
731 | raw_local_irq_save(flags); | |
732 | if (!graph_lock()) { | |
733 | raw_local_irq_restore(flags); | |
734 | return NULL; | |
735 | } | |
736 | /* | |
737 | * We have to do the hash-walk again, to avoid races | |
738 | * with another CPU: | |
739 | */ | |
740 | list_for_each_entry(class, hash_head, hash_entry) | |
741 | if (class->key == key) | |
742 | goto out_unlock_set; | |
743 | /* | |
744 | * Allocate a new key from the static array, and add it to | |
745 | * the hash: | |
746 | */ | |
747 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
748 | if (!debug_locks_off_graph_unlock()) { | |
749 | raw_local_irq_restore(flags); | |
750 | return NULL; | |
751 | } | |
752 | raw_local_irq_restore(flags); | |
753 | ||
754 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
755 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 756 | dump_stack(); |
8e18257d PZ |
757 | return NULL; |
758 | } | |
759 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 760 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
761 | class->key = key; |
762 | class->name = lock->name; | |
763 | class->subclass = subclass; | |
764 | INIT_LIST_HEAD(&class->lock_entry); | |
765 | INIT_LIST_HEAD(&class->locks_before); | |
766 | INIT_LIST_HEAD(&class->locks_after); | |
767 | class->name_version = count_matching_names(class); | |
768 | /* | |
769 | * We use RCU's safe list-add method to make | |
770 | * parallel walking of the hash-list safe: | |
771 | */ | |
772 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
773 | /* |
774 | * Add it to the global list of classes: | |
775 | */ | |
776 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
777 | |
778 | if (verbose(class)) { | |
779 | graph_unlock(); | |
780 | raw_local_irq_restore(flags); | |
781 | ||
782 | printk("\nnew class %p: %s", class->key, class->name); | |
783 | if (class->name_version > 1) | |
784 | printk("#%d", class->name_version); | |
785 | printk("\n"); | |
786 | dump_stack(); | |
787 | ||
788 | raw_local_irq_save(flags); | |
789 | if (!graph_lock()) { | |
790 | raw_local_irq_restore(flags); | |
791 | return NULL; | |
792 | } | |
793 | } | |
794 | out_unlock_set: | |
795 | graph_unlock(); | |
796 | raw_local_irq_restore(flags); | |
797 | ||
798 | if (!subclass || force) | |
62016250 HM |
799 | lock->class_cache[0] = class; |
800 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
801 | lock->class_cache[subclass] = class; | |
8e18257d PZ |
802 | |
803 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
804 | return NULL; | |
805 | ||
806 | return class; | |
807 | } | |
808 | ||
809 | #ifdef CONFIG_PROVE_LOCKING | |
810 | /* | |
811 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
812 | * with NULL on failure) | |
813 | */ | |
814 | static struct lock_list *alloc_list_entry(void) | |
815 | { | |
816 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
817 | if (!debug_locks_off_graph_unlock()) | |
818 | return NULL; | |
819 | ||
820 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
821 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 822 | dump_stack(); |
8e18257d PZ |
823 | return NULL; |
824 | } | |
825 | return list_entries + nr_list_entries++; | |
826 | } | |
827 | ||
828 | /* | |
829 | * Add a new dependency to the head of the list: | |
830 | */ | |
831 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
4726f2a6 YZ |
832 | struct list_head *head, unsigned long ip, |
833 | int distance, struct stack_trace *trace) | |
8e18257d PZ |
834 | { |
835 | struct lock_list *entry; | |
836 | /* | |
837 | * Lock not present yet - get a new dependency struct and | |
838 | * add it to the list: | |
839 | */ | |
840 | entry = alloc_list_entry(); | |
841 | if (!entry) | |
842 | return 0; | |
843 | ||
74870172 ZY |
844 | entry->class = this; |
845 | entry->distance = distance; | |
4726f2a6 | 846 | entry->trace = *trace; |
8e18257d PZ |
847 | /* |
848 | * Since we never remove from the dependency list, the list can | |
849 | * be walked lockless by other CPUs, it's only allocation | |
850 | * that must be protected by the spinlock. But this also means | |
851 | * we must make new entries visible only once writes to the | |
852 | * entry become visible - hence the RCU op: | |
853 | */ | |
854 | list_add_tail_rcu(&entry->entry, head); | |
855 | ||
856 | return 1; | |
857 | } | |
858 | ||
98c33edd PZ |
859 | /* |
860 | * For good efficiency of modular, we use power of 2 | |
861 | */ | |
af012961 PZ |
862 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
863 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
864 | ||
98c33edd PZ |
865 | /* |
866 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
867 | * breadth-first search(BFS)algorithem, by which we can build |
868 | * the shortest path from the next lock to be acquired to the | |
869 | * previous held lock if there is a circular between them. | |
98c33edd | 870 | */ |
af012961 PZ |
871 | struct circular_queue { |
872 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
873 | unsigned int front, rear; | |
874 | }; | |
875 | ||
876 | static struct circular_queue lock_cq; | |
af012961 | 877 | |
12f3dfd0 | 878 | unsigned int max_bfs_queue_depth; |
af012961 | 879 | |
e351b660 ML |
880 | static unsigned int lockdep_dependency_gen_id; |
881 | ||
af012961 PZ |
882 | static inline void __cq_init(struct circular_queue *cq) |
883 | { | |
884 | cq->front = cq->rear = 0; | |
e351b660 | 885 | lockdep_dependency_gen_id++; |
af012961 PZ |
886 | } |
887 | ||
888 | static inline int __cq_empty(struct circular_queue *cq) | |
889 | { | |
890 | return (cq->front == cq->rear); | |
891 | } | |
892 | ||
893 | static inline int __cq_full(struct circular_queue *cq) | |
894 | { | |
895 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
896 | } | |
897 | ||
898 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
899 | { | |
900 | if (__cq_full(cq)) | |
901 | return -1; | |
902 | ||
903 | cq->element[cq->rear] = elem; | |
904 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
905 | return 0; | |
906 | } | |
907 | ||
908 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
909 | { | |
910 | if (__cq_empty(cq)) | |
911 | return -1; | |
912 | ||
913 | *elem = cq->element[cq->front]; | |
914 | cq->front = (cq->front + 1) & CQ_MASK; | |
915 | return 0; | |
916 | } | |
917 | ||
918 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
919 | { | |
920 | return (cq->rear - cq->front) & CQ_MASK; | |
921 | } | |
922 | ||
923 | static inline void mark_lock_accessed(struct lock_list *lock, | |
924 | struct lock_list *parent) | |
925 | { | |
926 | unsigned long nr; | |
98c33edd | 927 | |
af012961 PZ |
928 | nr = lock - list_entries; |
929 | WARN_ON(nr >= nr_list_entries); | |
930 | lock->parent = parent; | |
e351b660 | 931 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
932 | } |
933 | ||
934 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
935 | { | |
936 | unsigned long nr; | |
98c33edd | 937 | |
af012961 PZ |
938 | nr = lock - list_entries; |
939 | WARN_ON(nr >= nr_list_entries); | |
e351b660 | 940 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
941 | } |
942 | ||
943 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
944 | { | |
945 | return child->parent; | |
946 | } | |
947 | ||
948 | static inline int get_lock_depth(struct lock_list *child) | |
949 | { | |
950 | int depth = 0; | |
951 | struct lock_list *parent; | |
952 | ||
953 | while ((parent = get_lock_parent(child))) { | |
954 | child = parent; | |
955 | depth++; | |
956 | } | |
957 | return depth; | |
958 | } | |
959 | ||
9e2d551e | 960 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
961 | void *data, |
962 | int (*match)(struct lock_list *entry, void *data), | |
963 | struct lock_list **target_entry, | |
964 | int forward) | |
c94aa5ca ML |
965 | { |
966 | struct lock_list *entry; | |
d588e461 | 967 | struct list_head *head; |
c94aa5ca ML |
968 | struct circular_queue *cq = &lock_cq; |
969 | int ret = 1; | |
970 | ||
9e2d551e | 971 | if (match(source_entry, data)) { |
c94aa5ca ML |
972 | *target_entry = source_entry; |
973 | ret = 0; | |
974 | goto exit; | |
975 | } | |
976 | ||
d588e461 ML |
977 | if (forward) |
978 | head = &source_entry->class->locks_after; | |
979 | else | |
980 | head = &source_entry->class->locks_before; | |
981 | ||
982 | if (list_empty(head)) | |
983 | goto exit; | |
984 | ||
985 | __cq_init(cq); | |
c94aa5ca ML |
986 | __cq_enqueue(cq, (unsigned long)source_entry); |
987 | ||
988 | while (!__cq_empty(cq)) { | |
989 | struct lock_list *lock; | |
c94aa5ca ML |
990 | |
991 | __cq_dequeue(cq, (unsigned long *)&lock); | |
992 | ||
993 | if (!lock->class) { | |
994 | ret = -2; | |
995 | goto exit; | |
996 | } | |
997 | ||
998 | if (forward) | |
999 | head = &lock->class->locks_after; | |
1000 | else | |
1001 | head = &lock->class->locks_before; | |
1002 | ||
1003 | list_for_each_entry(entry, head, entry) { | |
1004 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 1005 | unsigned int cq_depth; |
c94aa5ca | 1006 | mark_lock_accessed(entry, lock); |
9e2d551e | 1007 | if (match(entry, data)) { |
c94aa5ca ML |
1008 | *target_entry = entry; |
1009 | ret = 0; | |
1010 | goto exit; | |
1011 | } | |
1012 | ||
1013 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1014 | ret = -1; | |
1015 | goto exit; | |
1016 | } | |
12f3dfd0 ML |
1017 | cq_depth = __cq_get_elem_count(cq); |
1018 | if (max_bfs_queue_depth < cq_depth) | |
1019 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1020 | } |
1021 | } | |
1022 | } | |
1023 | exit: | |
1024 | return ret; | |
1025 | } | |
1026 | ||
d7aaba14 | 1027 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1028 | void *data, |
1029 | int (*match)(struct lock_list *entry, void *data), | |
1030 | struct lock_list **target_entry) | |
c94aa5ca | 1031 | { |
9e2d551e | 1032 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1033 | |
1034 | } | |
1035 | ||
d7aaba14 | 1036 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1037 | void *data, |
1038 | int (*match)(struct lock_list *entry, void *data), | |
1039 | struct lock_list **target_entry) | |
c94aa5ca | 1040 | { |
9e2d551e | 1041 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1042 | |
1043 | } | |
1044 | ||
8e18257d PZ |
1045 | /* |
1046 | * Recursive, forwards-direction lock-dependency checking, used for | |
1047 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1048 | * checking. | |
8e18257d | 1049 | */ |
8e18257d PZ |
1050 | |
1051 | /* | |
1052 | * Print a dependency chain entry (this is only done when a deadlock | |
1053 | * has been detected): | |
1054 | */ | |
1055 | static noinline int | |
24208ca7 | 1056 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1057 | { |
1058 | if (debug_locks_silent) | |
1059 | return 0; | |
1060 | printk("\n-> #%u", depth); | |
1061 | print_lock_name(target->class); | |
1062 | printk(":\n"); | |
1063 | print_stack_trace(&target->trace, 6); | |
1064 | ||
1065 | return 0; | |
1066 | } | |
1067 | ||
f4185812 SR |
1068 | static void |
1069 | print_circular_lock_scenario(struct held_lock *src, | |
1070 | struct held_lock *tgt, | |
1071 | struct lock_list *prt) | |
1072 | { | |
1073 | struct lock_class *source = hlock_class(src); | |
1074 | struct lock_class *target = hlock_class(tgt); | |
1075 | struct lock_class *parent = prt->class; | |
1076 | ||
1077 | /* | |
1078 | * A direct locking problem where unsafe_class lock is taken | |
1079 | * directly by safe_class lock, then all we need to show | |
1080 | * is the deadlock scenario, as it is obvious that the | |
1081 | * unsafe lock is taken under the safe lock. | |
1082 | * | |
1083 | * But if there is a chain instead, where the safe lock takes | |
1084 | * an intermediate lock (middle_class) where this lock is | |
1085 | * not the same as the safe lock, then the lock chain is | |
1086 | * used to describe the problem. Otherwise we would need | |
1087 | * to show a different CPU case for each link in the chain | |
1088 | * from the safe_class lock to the unsafe_class lock. | |
1089 | */ | |
1090 | if (parent != source) { | |
1091 | printk("Chain exists of:\n "); | |
1092 | __print_lock_name(source); | |
1093 | printk(" --> "); | |
1094 | __print_lock_name(parent); | |
1095 | printk(" --> "); | |
1096 | __print_lock_name(target); | |
1097 | printk("\n\n"); | |
1098 | } | |
1099 | ||
1100 | printk(" Possible unsafe locking scenario:\n\n"); | |
1101 | printk(" CPU0 CPU1\n"); | |
1102 | printk(" ---- ----\n"); | |
1103 | printk(" lock("); | |
1104 | __print_lock_name(target); | |
1105 | printk(");\n"); | |
1106 | printk(" lock("); | |
1107 | __print_lock_name(parent); | |
1108 | printk(");\n"); | |
1109 | printk(" lock("); | |
1110 | __print_lock_name(target); | |
1111 | printk(");\n"); | |
1112 | printk(" lock("); | |
1113 | __print_lock_name(source); | |
1114 | printk(");\n"); | |
1115 | printk("\n *** DEADLOCK ***\n\n"); | |
1116 | } | |
1117 | ||
8e18257d PZ |
1118 | /* |
1119 | * When a circular dependency is detected, print the | |
1120 | * header first: | |
1121 | */ | |
1122 | static noinline int | |
db0002a3 ML |
1123 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1124 | struct held_lock *check_src, | |
1125 | struct held_lock *check_tgt) | |
8e18257d PZ |
1126 | { |
1127 | struct task_struct *curr = current; | |
1128 | ||
c94aa5ca | 1129 | if (debug_locks_silent) |
8e18257d PZ |
1130 | return 0; |
1131 | ||
b3fbab05 PM |
1132 | printk("\n"); |
1133 | printk("======================================================\n"); | |
1134 | printk("[ INFO: possible circular locking dependency detected ]\n"); | |
8e18257d | 1135 | print_kernel_version(); |
b3fbab05 | 1136 | printk("-------------------------------------------------------\n"); |
8e18257d | 1137 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1138 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1139 | print_lock(check_src); |
8e18257d | 1140 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1141 | print_lock(check_tgt); |
8e18257d PZ |
1142 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1143 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1144 | ||
1145 | print_circular_bug_entry(entry, depth); | |
1146 | ||
1147 | return 0; | |
1148 | } | |
1149 | ||
9e2d551e ML |
1150 | static inline int class_equal(struct lock_list *entry, void *data) |
1151 | { | |
1152 | return entry->class == data; | |
1153 | } | |
1154 | ||
db0002a3 ML |
1155 | static noinline int print_circular_bug(struct lock_list *this, |
1156 | struct lock_list *target, | |
1157 | struct held_lock *check_src, | |
1158 | struct held_lock *check_tgt) | |
8e18257d PZ |
1159 | { |
1160 | struct task_struct *curr = current; | |
c94aa5ca | 1161 | struct lock_list *parent; |
f4185812 | 1162 | struct lock_list *first_parent; |
24208ca7 | 1163 | int depth; |
8e18257d | 1164 | |
c94aa5ca | 1165 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1166 | return 0; |
1167 | ||
db0002a3 | 1168 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1169 | return 0; |
1170 | ||
c94aa5ca ML |
1171 | depth = get_lock_depth(target); |
1172 | ||
db0002a3 | 1173 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1174 | |
1175 | parent = get_lock_parent(target); | |
f4185812 | 1176 | first_parent = parent; |
c94aa5ca ML |
1177 | |
1178 | while (parent) { | |
1179 | print_circular_bug_entry(parent, --depth); | |
1180 | parent = get_lock_parent(parent); | |
1181 | } | |
8e18257d PZ |
1182 | |
1183 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1184 | print_circular_lock_scenario(check_src, check_tgt, |
1185 | first_parent); | |
1186 | ||
8e18257d PZ |
1187 | lockdep_print_held_locks(curr); |
1188 | ||
1189 | printk("\nstack backtrace:\n"); | |
1190 | dump_stack(); | |
1191 | ||
1192 | return 0; | |
1193 | } | |
1194 | ||
db0002a3 ML |
1195 | static noinline int print_bfs_bug(int ret) |
1196 | { | |
1197 | if (!debug_locks_off_graph_unlock()) | |
1198 | return 0; | |
1199 | ||
1200 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1201 | ||
1202 | return 0; | |
1203 | } | |
1204 | ||
ef681026 | 1205 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1206 | { |
ef681026 ML |
1207 | (*(unsigned long *)data)++; |
1208 | return 0; | |
1209 | } | |
419ca3f1 | 1210 | |
ef681026 ML |
1211 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1212 | { | |
1213 | unsigned long count = 0; | |
1214 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1215 | |
ef681026 | 1216 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1217 | |
ef681026 | 1218 | return count; |
419ca3f1 | 1219 | } |
419ca3f1 DM |
1220 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1221 | { | |
1222 | unsigned long ret, flags; | |
ef681026 ML |
1223 | struct lock_list this; |
1224 | ||
1225 | this.parent = NULL; | |
1226 | this.class = class; | |
419ca3f1 DM |
1227 | |
1228 | local_irq_save(flags); | |
0199c4e6 | 1229 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1230 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1231 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1232 | local_irq_restore(flags); |
1233 | ||
1234 | return ret; | |
1235 | } | |
1236 | ||
ef681026 | 1237 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1238 | { |
ef681026 ML |
1239 | unsigned long count = 0; |
1240 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1241 | |
ef681026 | 1242 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1243 | |
ef681026 | 1244 | return count; |
419ca3f1 DM |
1245 | } |
1246 | ||
1247 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1248 | { | |
1249 | unsigned long ret, flags; | |
ef681026 ML |
1250 | struct lock_list this; |
1251 | ||
1252 | this.parent = NULL; | |
1253 | this.class = class; | |
419ca3f1 DM |
1254 | |
1255 | local_irq_save(flags); | |
0199c4e6 | 1256 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1257 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1258 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1259 | local_irq_restore(flags); |
1260 | ||
1261 | return ret; | |
1262 | } | |
1263 | ||
8e18257d PZ |
1264 | /* |
1265 | * Prove that the dependency graph starting at <entry> can not | |
1266 | * lead to <target>. Print an error and return 0 if it does. | |
1267 | */ | |
1268 | static noinline int | |
db0002a3 ML |
1269 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1270 | struct lock_list **target_entry) | |
8e18257d | 1271 | { |
db0002a3 | 1272 | int result; |
8e18257d | 1273 | |
bd6d29c2 | 1274 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1275 | |
d7aaba14 | 1276 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1277 | |
db0002a3 ML |
1278 | return result; |
1279 | } | |
c94aa5ca | 1280 | |
81d68a96 | 1281 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1282 | /* |
1283 | * Forwards and backwards subgraph searching, for the purposes of | |
1284 | * proving that two subgraphs can be connected by a new dependency | |
1285 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1286 | */ | |
fbb9ce95 | 1287 | |
d7aaba14 ML |
1288 | static inline int usage_match(struct lock_list *entry, void *bit) |
1289 | { | |
1290 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1291 | } | |
1292 | ||
1293 | ||
1294 | ||
fbb9ce95 IM |
1295 | /* |
1296 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1297 | * at @root->class that matches @bit. |
fbb9ce95 | 1298 | * |
d7aaba14 ML |
1299 | * Return 0 if such a node exists in the subgraph, and put that node |
1300 | * into *@target_entry. | |
fbb9ce95 | 1301 | * |
d7aaba14 ML |
1302 | * Return 1 otherwise and keep *@target_entry unchanged. |
1303 | * Return <0 on error. | |
fbb9ce95 | 1304 | */ |
d7aaba14 ML |
1305 | static int |
1306 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1307 | struct lock_list **target_entry) | |
fbb9ce95 | 1308 | { |
d7aaba14 | 1309 | int result; |
fbb9ce95 | 1310 | |
bd6d29c2 | 1311 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1312 | |
d7aaba14 ML |
1313 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1314 | ||
1315 | return result; | |
fbb9ce95 IM |
1316 | } |
1317 | ||
1318 | /* | |
1319 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1320 | * at @root->class that matches @bit. |
fbb9ce95 | 1321 | * |
d7aaba14 ML |
1322 | * Return 0 if such a node exists in the subgraph, and put that node |
1323 | * into *@target_entry. | |
fbb9ce95 | 1324 | * |
d7aaba14 ML |
1325 | * Return 1 otherwise and keep *@target_entry unchanged. |
1326 | * Return <0 on error. | |
fbb9ce95 | 1327 | */ |
d7aaba14 ML |
1328 | static int |
1329 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1330 | struct lock_list **target_entry) | |
fbb9ce95 | 1331 | { |
d7aaba14 | 1332 | int result; |
fbb9ce95 | 1333 | |
bd6d29c2 | 1334 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1335 | |
d7aaba14 | 1336 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1337 | |
d7aaba14 | 1338 | return result; |
fbb9ce95 IM |
1339 | } |
1340 | ||
af012961 PZ |
1341 | static void print_lock_class_header(struct lock_class *class, int depth) |
1342 | { | |
1343 | int bit; | |
1344 | ||
1345 | printk("%*s->", depth, ""); | |
1346 | print_lock_name(class); | |
1347 | printk(" ops: %lu", class->ops); | |
1348 | printk(" {\n"); | |
1349 | ||
1350 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1351 | if (class->usage_mask & (1 << bit)) { | |
1352 | int len = depth; | |
1353 | ||
1354 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1355 | len += printk(" at:\n"); | |
1356 | print_stack_trace(class->usage_traces + bit, len); | |
1357 | } | |
1358 | } | |
1359 | printk("%*s }\n", depth, ""); | |
1360 | ||
1361 | printk("%*s ... key at: ",depth,""); | |
1362 | print_ip_sym((unsigned long)class->key); | |
1363 | } | |
1364 | ||
1365 | /* | |
1366 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1367 | */ | |
1368 | static void __used | |
1369 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1370 | struct lock_list *root) | |
1371 | { | |
1372 | struct lock_list *entry = leaf; | |
1373 | int depth; | |
1374 | ||
1375 | /*compute depth from generated tree by BFS*/ | |
1376 | depth = get_lock_depth(leaf); | |
1377 | ||
1378 | do { | |
1379 | print_lock_class_header(entry->class, depth); | |
1380 | printk("%*s ... acquired at:\n", depth, ""); | |
1381 | print_stack_trace(&entry->trace, 2); | |
1382 | printk("\n"); | |
1383 | ||
1384 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1385 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1386 | break; |
1387 | } | |
1388 | ||
1389 | entry = get_lock_parent(entry); | |
1390 | depth--; | |
1391 | } while (entry && (depth >= 0)); | |
1392 | ||
1393 | return; | |
1394 | } | |
d7aaba14 | 1395 | |
3003eba3 SR |
1396 | static void |
1397 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1398 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1399 | struct lock_class *prev_class, |
1400 | struct lock_class *next_class) | |
3003eba3 SR |
1401 | { |
1402 | struct lock_class *safe_class = safe_entry->class; | |
1403 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1404 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1405 | |
1406 | if (middle_class == safe_class) | |
dad3d743 | 1407 | middle_class = next_class; |
3003eba3 SR |
1408 | |
1409 | /* | |
1410 | * A direct locking problem where unsafe_class lock is taken | |
1411 | * directly by safe_class lock, then all we need to show | |
1412 | * is the deadlock scenario, as it is obvious that the | |
1413 | * unsafe lock is taken under the safe lock. | |
1414 | * | |
1415 | * But if there is a chain instead, where the safe lock takes | |
1416 | * an intermediate lock (middle_class) where this lock is | |
1417 | * not the same as the safe lock, then the lock chain is | |
1418 | * used to describe the problem. Otherwise we would need | |
1419 | * to show a different CPU case for each link in the chain | |
1420 | * from the safe_class lock to the unsafe_class lock. | |
1421 | */ | |
1422 | if (middle_class != unsafe_class) { | |
1423 | printk("Chain exists of:\n "); | |
1424 | __print_lock_name(safe_class); | |
1425 | printk(" --> "); | |
1426 | __print_lock_name(middle_class); | |
1427 | printk(" --> "); | |
1428 | __print_lock_name(unsafe_class); | |
1429 | printk("\n\n"); | |
1430 | } | |
1431 | ||
1432 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1433 | printk(" CPU0 CPU1\n"); | |
1434 | printk(" ---- ----\n"); | |
1435 | printk(" lock("); | |
1436 | __print_lock_name(unsafe_class); | |
1437 | printk(");\n"); | |
1438 | printk(" local_irq_disable();\n"); | |
1439 | printk(" lock("); | |
1440 | __print_lock_name(safe_class); | |
1441 | printk(");\n"); | |
1442 | printk(" lock("); | |
1443 | __print_lock_name(middle_class); | |
1444 | printk(");\n"); | |
1445 | printk(" <Interrupt>\n"); | |
1446 | printk(" lock("); | |
1447 | __print_lock_name(safe_class); | |
1448 | printk(");\n"); | |
1449 | printk("\n *** DEADLOCK ***\n\n"); | |
1450 | } | |
1451 | ||
fbb9ce95 IM |
1452 | static int |
1453 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1454 | struct lock_list *prev_root, |
1455 | struct lock_list *next_root, | |
1456 | struct lock_list *backwards_entry, | |
1457 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1458 | struct held_lock *prev, |
1459 | struct held_lock *next, | |
1460 | enum lock_usage_bit bit1, | |
1461 | enum lock_usage_bit bit2, | |
1462 | const char *irqclass) | |
1463 | { | |
74c383f1 | 1464 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1465 | return 0; |
1466 | ||
b3fbab05 PM |
1467 | printk("\n"); |
1468 | printk("======================================================\n"); | |
1469 | printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
fbb9ce95 | 1470 | irqclass, irqclass); |
99de055a | 1471 | print_kernel_version(); |
b3fbab05 | 1472 | printk("------------------------------------------------------\n"); |
fbb9ce95 | 1473 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
ba25f9dc | 1474 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1475 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1476 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1477 | curr->hardirqs_enabled, | |
1478 | curr->softirqs_enabled); | |
1479 | print_lock(next); | |
1480 | ||
1481 | printk("\nand this task is already holding:\n"); | |
1482 | print_lock(prev); | |
1483 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1484 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1485 | printk(" ->"); |
f82b217e | 1486 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1487 | printk("\n"); |
1488 | ||
1489 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1490 | irqclass); | |
24208ca7 | 1491 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1492 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1493 | ||
24208ca7 | 1494 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1495 | |
1496 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1497 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1498 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1499 | printk("..."); | |
1500 | ||
24208ca7 | 1501 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1502 | |
1503 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1504 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1505 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1506 | |
fbb9ce95 IM |
1507 | lockdep_print_held_locks(curr); |
1508 | ||
24208ca7 ML |
1509 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1510 | printk(" and the holding lock:\n"); | |
1511 | if (!save_trace(&prev_root->trace)) | |
1512 | return 0; | |
1513 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1514 | |
24208ca7 ML |
1515 | printk("\nthe dependencies between the lock to be acquired"); |
1516 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1517 | if (!save_trace(&next_root->trace)) | |
1518 | return 0; | |
1519 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1520 | |
1521 | printk("\nstack backtrace:\n"); | |
1522 | dump_stack(); | |
1523 | ||
1524 | return 0; | |
1525 | } | |
1526 | ||
1527 | static int | |
1528 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1529 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1530 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1531 | { | |
1532 | int ret; | |
24208ca7 | 1533 | struct lock_list this, that; |
d7aaba14 | 1534 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1535 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1536 | |
1537 | this.parent = NULL; | |
1538 | ||
1539 | this.class = hlock_class(prev); | |
1540 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1541 | if (ret < 0) |
1542 | return print_bfs_bug(ret); | |
1543 | if (ret == 1) | |
1544 | return ret; | |
d7aaba14 | 1545 | |
24208ca7 ML |
1546 | that.parent = NULL; |
1547 | that.class = hlock_class(next); | |
1548 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1549 | if (ret < 0) |
1550 | return print_bfs_bug(ret); | |
1551 | if (ret == 1) | |
1552 | return ret; | |
fbb9ce95 | 1553 | |
24208ca7 ML |
1554 | return print_bad_irq_dependency(curr, &this, &that, |
1555 | target_entry, target_entry1, | |
1556 | prev, next, | |
fbb9ce95 IM |
1557 | bit_backwards, bit_forwards, irqclass); |
1558 | } | |
1559 | ||
4f367d8a PZ |
1560 | static const char *state_names[] = { |
1561 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1562 | __stringify(__STATE), |
4f367d8a PZ |
1563 | #include "lockdep_states.h" |
1564 | #undef LOCKDEP_STATE | |
1565 | }; | |
1566 | ||
1567 | static const char *state_rnames[] = { | |
1568 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1569 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1570 | #include "lockdep_states.h" |
1571 | #undef LOCKDEP_STATE | |
1572 | }; | |
1573 | ||
1574 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1575 | { |
4f367d8a PZ |
1576 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1577 | } | |
8e18257d | 1578 | |
4f367d8a PZ |
1579 | static int exclusive_bit(int new_bit) |
1580 | { | |
8e18257d | 1581 | /* |
4f367d8a PZ |
1582 | * USED_IN |
1583 | * USED_IN_READ | |
1584 | * ENABLED | |
1585 | * ENABLED_READ | |
1586 | * | |
1587 | * bit 0 - write/read | |
1588 | * bit 1 - used_in/enabled | |
1589 | * bit 2+ state | |
8e18257d | 1590 | */ |
4f367d8a PZ |
1591 | |
1592 | int state = new_bit & ~3; | |
1593 | int dir = new_bit & 2; | |
8e18257d PZ |
1594 | |
1595 | /* | |
4f367d8a | 1596 | * keep state, bit flip the direction and strip read. |
8e18257d | 1597 | */ |
4f367d8a PZ |
1598 | return state | (dir ^ 2); |
1599 | } | |
1600 | ||
1601 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1602 | struct held_lock *next, enum lock_usage_bit bit) | |
1603 | { | |
8e18257d | 1604 | /* |
4f367d8a PZ |
1605 | * Prove that the new dependency does not connect a hardirq-safe |
1606 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1607 | * the backwards-subgraph starting at <prev>, and the |
1608 | * forwards-subgraph starting at <next>: | |
1609 | */ | |
4f367d8a PZ |
1610 | if (!check_usage(curr, prev, next, bit, |
1611 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1612 | return 0; |
1613 | ||
4f367d8a PZ |
1614 | bit++; /* _READ */ |
1615 | ||
cf40bd16 | 1616 | /* |
4f367d8a PZ |
1617 | * Prove that the new dependency does not connect a hardirq-safe-read |
1618 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1619 | * the backwards-subgraph starting at <prev>, and the |
1620 | * forwards-subgraph starting at <next>: | |
1621 | */ | |
4f367d8a PZ |
1622 | if (!check_usage(curr, prev, next, bit, |
1623 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1624 | return 0; |
1625 | ||
4f367d8a PZ |
1626 | return 1; |
1627 | } | |
1628 | ||
1629 | static int | |
1630 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1631 | struct held_lock *next) | |
1632 | { | |
1633 | #define LOCKDEP_STATE(__STATE) \ | |
1634 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1635 | return 0; |
4f367d8a PZ |
1636 | #include "lockdep_states.h" |
1637 | #undef LOCKDEP_STATE | |
cf40bd16 | 1638 | |
8e18257d PZ |
1639 | return 1; |
1640 | } | |
1641 | ||
1642 | static void inc_chains(void) | |
1643 | { | |
1644 | if (current->hardirq_context) | |
1645 | nr_hardirq_chains++; | |
1646 | else { | |
1647 | if (current->softirq_context) | |
1648 | nr_softirq_chains++; | |
1649 | else | |
1650 | nr_process_chains++; | |
1651 | } | |
1652 | } | |
1653 | ||
1654 | #else | |
1655 | ||
1656 | static inline int | |
1657 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1658 | struct held_lock *next) | |
1659 | { | |
1660 | return 1; | |
1661 | } | |
1662 | ||
1663 | static inline void inc_chains(void) | |
1664 | { | |
1665 | nr_process_chains++; | |
1666 | } | |
1667 | ||
fbb9ce95 IM |
1668 | #endif |
1669 | ||
48702ecf SR |
1670 | static void |
1671 | print_deadlock_scenario(struct held_lock *nxt, | |
1672 | struct held_lock *prv) | |
1673 | { | |
1674 | struct lock_class *next = hlock_class(nxt); | |
1675 | struct lock_class *prev = hlock_class(prv); | |
1676 | ||
1677 | printk(" Possible unsafe locking scenario:\n\n"); | |
1678 | printk(" CPU0\n"); | |
1679 | printk(" ----\n"); | |
1680 | printk(" lock("); | |
1681 | __print_lock_name(prev); | |
1682 | printk(");\n"); | |
1683 | printk(" lock("); | |
1684 | __print_lock_name(next); | |
1685 | printk(");\n"); | |
1686 | printk("\n *** DEADLOCK ***\n\n"); | |
1687 | printk(" May be due to missing lock nesting notation\n\n"); | |
1688 | } | |
1689 | ||
fbb9ce95 IM |
1690 | static int |
1691 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1692 | struct held_lock *next) | |
1693 | { | |
74c383f1 | 1694 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1695 | return 0; |
1696 | ||
b3fbab05 PM |
1697 | printk("\n"); |
1698 | printk("=============================================\n"); | |
1699 | printk("[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1700 | print_kernel_version(); |
b3fbab05 | 1701 | printk("---------------------------------------------\n"); |
fbb9ce95 | 1702 | printk("%s/%d is trying to acquire lock:\n", |
ba25f9dc | 1703 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1704 | print_lock(next); |
1705 | printk("\nbut task is already holding lock:\n"); | |
1706 | print_lock(prev); | |
1707 | ||
1708 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1709 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1710 | lockdep_print_held_locks(curr); |
1711 | ||
1712 | printk("\nstack backtrace:\n"); | |
1713 | dump_stack(); | |
1714 | ||
1715 | return 0; | |
1716 | } | |
1717 | ||
1718 | /* | |
1719 | * Check whether we are holding such a class already. | |
1720 | * | |
1721 | * (Note that this has to be done separately, because the graph cannot | |
1722 | * detect such classes of deadlocks.) | |
1723 | * | |
1724 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1725 | */ | |
1726 | static int | |
1727 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1728 | struct lockdep_map *next_instance, int read) | |
1729 | { | |
1730 | struct held_lock *prev; | |
7531e2f3 | 1731 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1732 | int i; |
1733 | ||
1734 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1735 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1736 | |
1737 | if (prev->instance == next->nest_lock) | |
1738 | nest = prev; | |
1739 | ||
f82b217e | 1740 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1741 | continue; |
7531e2f3 | 1742 | |
fbb9ce95 IM |
1743 | /* |
1744 | * Allow read-after-read recursion of the same | |
6c9076ec | 1745 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1746 | */ |
6c9076ec | 1747 | if ((read == 2) && prev->read) |
fbb9ce95 | 1748 | return 2; |
7531e2f3 PZ |
1749 | |
1750 | /* | |
1751 | * We're holding the nest_lock, which serializes this lock's | |
1752 | * nesting behaviour. | |
1753 | */ | |
1754 | if (nest) | |
1755 | return 2; | |
1756 | ||
fbb9ce95 IM |
1757 | return print_deadlock_bug(curr, prev, next); |
1758 | } | |
1759 | return 1; | |
1760 | } | |
1761 | ||
1762 | /* | |
1763 | * There was a chain-cache miss, and we are about to add a new dependency | |
1764 | * to a previous lock. We recursively validate the following rules: | |
1765 | * | |
1766 | * - would the adding of the <prev> -> <next> dependency create a | |
1767 | * circular dependency in the graph? [== circular deadlock] | |
1768 | * | |
1769 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1770 | * (in the full backwards-subgraph starting at <prev>) with any | |
1771 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1772 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1773 | * | |
1774 | * - does the new prev->next dependency connect any softirq-safe lock | |
1775 | * (in the full backwards-subgraph starting at <prev>) with any | |
1776 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1777 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1778 | * | |
1779 | * any of these scenarios could lead to a deadlock. | |
1780 | * | |
1781 | * Then if all the validations pass, we add the forwards and backwards | |
1782 | * dependency. | |
1783 | */ | |
1784 | static int | |
1785 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
4726f2a6 | 1786 | struct held_lock *next, int distance, int trylock_loop) |
fbb9ce95 IM |
1787 | { |
1788 | struct lock_list *entry; | |
1789 | int ret; | |
db0002a3 ML |
1790 | struct lock_list this; |
1791 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1792 | /* |
1793 | * Static variable, serialized by the graph_lock(). | |
1794 | * | |
1795 | * We use this static variable to save the stack trace in case | |
1796 | * we call into this function multiple times due to encountering | |
1797 | * trylocks in the held lock stack. | |
1798 | */ | |
1799 | static struct stack_trace trace; | |
fbb9ce95 IM |
1800 | |
1801 | /* | |
1802 | * Prove that the new <prev> -> <next> dependency would not | |
1803 | * create a circular dependency in the graph. (We do this by | |
1804 | * forward-recursing into the graph starting at <next>, and | |
1805 | * checking whether we can reach <prev>.) | |
1806 | * | |
1807 | * We are using global variables to control the recursion, to | |
1808 | * keep the stackframe size of the recursive functions low: | |
1809 | */ | |
db0002a3 ML |
1810 | this.class = hlock_class(next); |
1811 | this.parent = NULL; | |
1812 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1813 | if (unlikely(!ret)) | |
1814 | return print_circular_bug(&this, target_entry, next, prev); | |
1815 | else if (unlikely(ret < 0)) | |
1816 | return print_bfs_bug(ret); | |
c94aa5ca | 1817 | |
8e18257d | 1818 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1819 | return 0; |
1820 | ||
fbb9ce95 IM |
1821 | /* |
1822 | * For recursive read-locks we do all the dependency checks, | |
1823 | * but we dont store read-triggered dependencies (only | |
1824 | * write-triggered dependencies). This ensures that only the | |
1825 | * write-side dependencies matter, and that if for example a | |
1826 | * write-lock never takes any other locks, then the reads are | |
1827 | * equivalent to a NOP. | |
1828 | */ | |
1829 | if (next->read == 2 || prev->read == 2) | |
1830 | return 1; | |
1831 | /* | |
1832 | * Is the <prev> -> <next> dependency already present? | |
1833 | * | |
1834 | * (this may occur even though this is a new chain: consider | |
1835 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1836 | * chains - the second one will be new, but L1 already has | |
1837 | * L2 added to its dependency list, due to the first chain.) | |
1838 | */ | |
f82b217e DJ |
1839 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1840 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1841 | if (distance == 1) |
1842 | entry->distance = 1; | |
fbb9ce95 | 1843 | return 2; |
068135e6 | 1844 | } |
fbb9ce95 IM |
1845 | } |
1846 | ||
4726f2a6 YZ |
1847 | if (!trylock_loop && !save_trace(&trace)) |
1848 | return 0; | |
1849 | ||
fbb9ce95 IM |
1850 | /* |
1851 | * Ok, all validations passed, add the new lock | |
1852 | * to the previous lock's dependency list: | |
1853 | */ | |
f82b217e DJ |
1854 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1855 | &hlock_class(prev)->locks_after, | |
4726f2a6 | 1856 | next->acquire_ip, distance, &trace); |
068135e6 | 1857 | |
fbb9ce95 IM |
1858 | if (!ret) |
1859 | return 0; | |
910b1b2e | 1860 | |
f82b217e DJ |
1861 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1862 | &hlock_class(next)->locks_before, | |
4726f2a6 | 1863 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1864 | if (!ret) |
1865 | return 0; | |
fbb9ce95 IM |
1866 | |
1867 | /* | |
8e18257d PZ |
1868 | * Debugging printouts: |
1869 | */ | |
f82b217e | 1870 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1871 | graph_unlock(); |
1872 | printk("\n new dependency: "); | |
f82b217e | 1873 | print_lock_name(hlock_class(prev)); |
8e18257d | 1874 | printk(" => "); |
f82b217e | 1875 | print_lock_name(hlock_class(next)); |
8e18257d | 1876 | printk("\n"); |
fbb9ce95 | 1877 | dump_stack(); |
8e18257d | 1878 | return graph_lock(); |
fbb9ce95 | 1879 | } |
8e18257d PZ |
1880 | return 1; |
1881 | } | |
fbb9ce95 | 1882 | |
8e18257d PZ |
1883 | /* |
1884 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1885 | * The ones that are relevant are (in increasing distance from curr): | |
1886 | * all consecutive trylock entries and the final non-trylock entry - or | |
1887 | * the end of this context's lock-chain - whichever comes first. | |
1888 | */ | |
1889 | static int | |
1890 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1891 | { | |
1892 | int depth = curr->lockdep_depth; | |
4726f2a6 | 1893 | int trylock_loop = 0; |
8e18257d | 1894 | struct held_lock *hlock; |
d6d897ce | 1895 | |
fbb9ce95 | 1896 | /* |
8e18257d PZ |
1897 | * Debugging checks. |
1898 | * | |
1899 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1900 | */ |
8e18257d PZ |
1901 | if (!depth) |
1902 | goto out_bug; | |
fbb9ce95 | 1903 | /* |
8e18257d PZ |
1904 | * At least two relevant locks must exist for this |
1905 | * to be a head: | |
fbb9ce95 | 1906 | */ |
8e18257d PZ |
1907 | if (curr->held_locks[depth].irq_context != |
1908 | curr->held_locks[depth-1].irq_context) | |
1909 | goto out_bug; | |
74c383f1 | 1910 | |
8e18257d PZ |
1911 | for (;;) { |
1912 | int distance = curr->lockdep_depth - depth + 1; | |
1913 | hlock = curr->held_locks + depth-1; | |
1914 | /* | |
1915 | * Only non-recursive-read entries get new dependencies | |
1916 | * added: | |
1917 | */ | |
1918 | if (hlock->read != 2) { | |
4726f2a6 YZ |
1919 | if (!check_prev_add(curr, hlock, next, |
1920 | distance, trylock_loop)) | |
8e18257d PZ |
1921 | return 0; |
1922 | /* | |
1923 | * Stop after the first non-trylock entry, | |
1924 | * as non-trylock entries have added their | |
1925 | * own direct dependencies already, so this | |
1926 | * lock is connected to them indirectly: | |
1927 | */ | |
1928 | if (!hlock->trylock) | |
1929 | break; | |
74c383f1 | 1930 | } |
8e18257d PZ |
1931 | depth--; |
1932 | /* | |
1933 | * End of lock-stack? | |
1934 | */ | |
1935 | if (!depth) | |
1936 | break; | |
1937 | /* | |
1938 | * Stop the search if we cross into another context: | |
1939 | */ | |
1940 | if (curr->held_locks[depth].irq_context != | |
1941 | curr->held_locks[depth-1].irq_context) | |
1942 | break; | |
4726f2a6 | 1943 | trylock_loop = 1; |
fbb9ce95 | 1944 | } |
8e18257d PZ |
1945 | return 1; |
1946 | out_bug: | |
1947 | if (!debug_locks_off_graph_unlock()) | |
1948 | return 0; | |
fbb9ce95 | 1949 | |
8e18257d | 1950 | WARN_ON(1); |
fbb9ce95 | 1951 | |
8e18257d | 1952 | return 0; |
fbb9ce95 IM |
1953 | } |
1954 | ||
8e18257d | 1955 | unsigned long nr_lock_chains; |
443cd507 | 1956 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1957 | int nr_chain_hlocks; |
443cd507 HY |
1958 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1959 | ||
1960 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1961 | { | |
1962 | return lock_classes + chain_hlocks[chain->base + i]; | |
1963 | } | |
8e18257d | 1964 | |
fbb9ce95 IM |
1965 | /* |
1966 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1967 | * add it and return 1 - in this case the new dependency chain is |
1968 | * validated. If the key is already hashed, return 0. | |
1969 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1970 | */ |
443cd507 HY |
1971 | static inline int lookup_chain_cache(struct task_struct *curr, |
1972 | struct held_lock *hlock, | |
1973 | u64 chain_key) | |
fbb9ce95 | 1974 | { |
f82b217e | 1975 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1976 | struct list_head *hash_head = chainhashentry(chain_key); |
1977 | struct lock_chain *chain; | |
443cd507 | 1978 | struct held_lock *hlock_curr, *hlock_next; |
e0944ee6 | 1979 | int i, j; |
fbb9ce95 | 1980 | |
381a2292 JP |
1981 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1982 | return 0; | |
fbb9ce95 IM |
1983 | /* |
1984 | * We can walk it lock-free, because entries only get added | |
1985 | * to the hash: | |
1986 | */ | |
1987 | list_for_each_entry(chain, hash_head, entry) { | |
1988 | if (chain->chain_key == chain_key) { | |
1989 | cache_hit: | |
bd6d29c2 | 1990 | debug_atomic_inc(chain_lookup_hits); |
81fc685a | 1991 | if (very_verbose(class)) |
755cd900 AM |
1992 | printk("\nhash chain already cached, key: " |
1993 | "%016Lx tail class: [%p] %s\n", | |
1994 | (unsigned long long)chain_key, | |
1995 | class->key, class->name); | |
fbb9ce95 IM |
1996 | return 0; |
1997 | } | |
1998 | } | |
81fc685a | 1999 | if (very_verbose(class)) |
755cd900 AM |
2000 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
2001 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
2002 | /* |
2003 | * Allocate a new chain entry from the static array, and add | |
2004 | * it to the hash: | |
2005 | */ | |
74c383f1 IM |
2006 | if (!graph_lock()) |
2007 | return 0; | |
fbb9ce95 IM |
2008 | /* |
2009 | * We have to walk the chain again locked - to avoid duplicates: | |
2010 | */ | |
2011 | list_for_each_entry(chain, hash_head, entry) { | |
2012 | if (chain->chain_key == chain_key) { | |
74c383f1 | 2013 | graph_unlock(); |
fbb9ce95 IM |
2014 | goto cache_hit; |
2015 | } | |
2016 | } | |
2017 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2018 | if (!debug_locks_off_graph_unlock()) |
2019 | return 0; | |
2020 | ||
fbb9ce95 IM |
2021 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
2022 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2023 | dump_stack(); |
fbb9ce95 IM |
2024 | return 0; |
2025 | } | |
2026 | chain = lock_chains + nr_lock_chains++; | |
2027 | chain->chain_key = chain_key; | |
443cd507 HY |
2028 | chain->irq_context = hlock->irq_context; |
2029 | /* Find the first held_lock of current chain */ | |
2030 | hlock_next = hlock; | |
2031 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2032 | hlock_curr = curr->held_locks + i; | |
2033 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
2034 | break; | |
2035 | hlock_next = hlock; | |
2036 | } | |
2037 | i++; | |
2038 | chain->depth = curr->lockdep_depth + 1 - i; | |
e0944ee6 SR |
2039 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2040 | chain->base = nr_chain_hlocks; | |
2041 | nr_chain_hlocks += chain->depth; | |
443cd507 | 2042 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2043 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2044 | chain_hlocks[chain->base + j] = lock_id; |
2045 | } | |
2046 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2047 | } | |
fbb9ce95 | 2048 | list_add_tail_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2049 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2050 | inc_chains(); |
2051 | ||
2052 | return 1; | |
2053 | } | |
2054 | ||
2055 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2056 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2057 | { |
2058 | /* | |
2059 | * Trylock needs to maintain the stack of held locks, but it | |
2060 | * does not add new dependencies, because trylock can be done | |
2061 | * in any order. | |
2062 | * | |
2063 | * We look up the chain_key and do the O(N^2) check and update of | |
2064 | * the dependencies only if this is a new dependency chain. | |
2065 | * (If lookup_chain_cache() returns with 1 it acquires | |
2066 | * graph_lock for us) | |
2067 | */ | |
2068 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 2069 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2070 | /* |
2071 | * Check whether last held lock: | |
2072 | * | |
2073 | * - is irq-safe, if this lock is irq-unsafe | |
2074 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2075 | * | |
2076 | * And check whether the new lock's dependency graph | |
2077 | * could lead back to the previous lock. | |
2078 | * | |
2079 | * any of these scenarios could lead to a deadlock. If | |
2080 | * All validations | |
2081 | */ | |
2082 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2083 | ||
2084 | if (!ret) | |
2085 | return 0; | |
2086 | /* | |
2087 | * Mark recursive read, as we jump over it when | |
2088 | * building dependencies (just like we jump over | |
2089 | * trylock entries): | |
2090 | */ | |
2091 | if (ret == 2) | |
2092 | hlock->read = 2; | |
2093 | /* | |
2094 | * Add dependency only if this lock is not the head | |
2095 | * of the chain, and if it's not a secondary read-lock: | |
2096 | */ | |
2097 | if (!chain_head && ret != 2) | |
2098 | if (!check_prevs_add(curr, hlock)) | |
2099 | return 0; | |
2100 | graph_unlock(); | |
2101 | } else | |
2102 | /* after lookup_chain_cache(): */ | |
2103 | if (unlikely(!debug_locks)) | |
2104 | return 0; | |
fbb9ce95 IM |
2105 | |
2106 | return 1; | |
2107 | } | |
8e18257d PZ |
2108 | #else |
2109 | static inline int validate_chain(struct task_struct *curr, | |
2110 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2111 | int chain_head, u64 chain_key) |
8e18257d PZ |
2112 | { |
2113 | return 1; | |
2114 | } | |
ca58abcb | 2115 | #endif |
fbb9ce95 IM |
2116 | |
2117 | /* | |
2118 | * We are building curr_chain_key incrementally, so double-check | |
2119 | * it from scratch, to make sure that it's done correctly: | |
2120 | */ | |
1d09daa5 | 2121 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2122 | { |
2123 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2124 | struct held_lock *hlock, *prev_hlock = NULL; | |
2125 | unsigned int i, id; | |
2126 | u64 chain_key = 0; | |
2127 | ||
2128 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2129 | hlock = curr->held_locks + i; | |
2130 | if (chain_key != hlock->prev_chain_key) { | |
2131 | debug_locks_off(); | |
2df8b1d6 | 2132 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2133 | curr->lockdep_depth, i, |
2134 | (unsigned long long)chain_key, | |
2135 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2136 | return; |
2137 | } | |
f82b217e | 2138 | id = hlock->class_idx - 1; |
381a2292 JP |
2139 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
2140 | return; | |
2141 | ||
fbb9ce95 IM |
2142 | if (prev_hlock && (prev_hlock->irq_context != |
2143 | hlock->irq_context)) | |
2144 | chain_key = 0; | |
2145 | chain_key = iterate_chain_key(chain_key, id); | |
2146 | prev_hlock = hlock; | |
2147 | } | |
2148 | if (chain_key != curr->curr_chain_key) { | |
2149 | debug_locks_off(); | |
2df8b1d6 | 2150 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2151 | curr->lockdep_depth, i, |
2152 | (unsigned long long)chain_key, | |
2153 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2154 | } |
2155 | #endif | |
2156 | } | |
2157 | ||
282b5c2f SR |
2158 | static void |
2159 | print_usage_bug_scenario(struct held_lock *lock) | |
2160 | { | |
2161 | struct lock_class *class = hlock_class(lock); | |
2162 | ||
2163 | printk(" Possible unsafe locking scenario:\n\n"); | |
2164 | printk(" CPU0\n"); | |
2165 | printk(" ----\n"); | |
2166 | printk(" lock("); | |
2167 | __print_lock_name(class); | |
2168 | printk(");\n"); | |
2169 | printk(" <Interrupt>\n"); | |
2170 | printk(" lock("); | |
2171 | __print_lock_name(class); | |
2172 | printk(");\n"); | |
2173 | printk("\n *** DEADLOCK ***\n\n"); | |
2174 | } | |
2175 | ||
8e18257d PZ |
2176 | static int |
2177 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2178 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2179 | { | |
2180 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2181 | return 0; | |
2182 | ||
b3fbab05 PM |
2183 | printk("\n"); |
2184 | printk("=================================\n"); | |
2185 | printk("[ INFO: inconsistent lock state ]\n"); | |
8e18257d | 2186 | print_kernel_version(); |
b3fbab05 | 2187 | printk("---------------------------------\n"); |
8e18257d PZ |
2188 | |
2189 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2190 | usage_str[prev_bit], usage_str[new_bit]); | |
2191 | ||
2192 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2193 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2194 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2195 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2196 | trace_hardirqs_enabled(curr), | |
2197 | trace_softirqs_enabled(curr)); | |
2198 | print_lock(this); | |
2199 | ||
2200 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2201 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2202 | |
2203 | print_irqtrace_events(curr); | |
2204 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2205 | print_usage_bug_scenario(this); |
2206 | ||
8e18257d PZ |
2207 | lockdep_print_held_locks(curr); |
2208 | ||
2209 | printk("\nstack backtrace:\n"); | |
2210 | dump_stack(); | |
2211 | ||
2212 | return 0; | |
2213 | } | |
2214 | ||
2215 | /* | |
2216 | * Print out an error if an invalid bit is set: | |
2217 | */ | |
2218 | static inline int | |
2219 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2220 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2221 | { | |
f82b217e | 2222 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2223 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2224 | return 1; | |
2225 | } | |
2226 | ||
2227 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2228 | enum lock_usage_bit new_bit); | |
2229 | ||
81d68a96 | 2230 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2231 | |
2232 | /* | |
2233 | * print irq inversion bug: | |
2234 | */ | |
2235 | static int | |
24208ca7 ML |
2236 | print_irq_inversion_bug(struct task_struct *curr, |
2237 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2238 | struct held_lock *this, int forwards, |
2239 | const char *irqclass) | |
2240 | { | |
dad3d743 SR |
2241 | struct lock_list *entry = other; |
2242 | struct lock_list *middle = NULL; | |
2243 | int depth; | |
2244 | ||
74c383f1 | 2245 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2246 | return 0; |
2247 | ||
b3fbab05 PM |
2248 | printk("\n"); |
2249 | printk("=========================================================\n"); | |
2250 | printk("[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2251 | print_kernel_version(); |
b3fbab05 | 2252 | printk("---------------------------------------------------------\n"); |
fbb9ce95 | 2253 | printk("%s/%d just changed the state of lock:\n", |
ba25f9dc | 2254 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2255 | print_lock(this); |
2256 | if (forwards) | |
26575e28 | 2257 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2258 | else |
26575e28 | 2259 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2260 | print_lock_name(other->class); |
fbb9ce95 IM |
2261 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2262 | ||
2263 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2264 | |
2265 | /* Find a middle lock (if one exists) */ | |
2266 | depth = get_lock_depth(other); | |
2267 | do { | |
2268 | if (depth == 0 && (entry != root)) { | |
2269 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2270 | break; | |
2271 | } | |
2272 | middle = entry; | |
2273 | entry = get_lock_parent(entry); | |
2274 | depth--; | |
2275 | } while (entry && entry != root && (depth >= 0)); | |
2276 | if (forwards) | |
2277 | print_irq_lock_scenario(root, other, | |
2278 | middle ? middle->class : root->class, other->class); | |
2279 | else | |
2280 | print_irq_lock_scenario(other, root, | |
2281 | middle ? middle->class : other->class, root->class); | |
2282 | ||
fbb9ce95 IM |
2283 | lockdep_print_held_locks(curr); |
2284 | ||
24208ca7 ML |
2285 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2286 | if (!save_trace(&root->trace)) | |
2287 | return 0; | |
2288 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2289 | |
2290 | printk("\nstack backtrace:\n"); | |
2291 | dump_stack(); | |
2292 | ||
2293 | return 0; | |
2294 | } | |
2295 | ||
2296 | /* | |
2297 | * Prove that in the forwards-direction subgraph starting at <this> | |
2298 | * there is no lock matching <mask>: | |
2299 | */ | |
2300 | static int | |
2301 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2302 | enum lock_usage_bit bit, const char *irqclass) | |
2303 | { | |
2304 | int ret; | |
d7aaba14 ML |
2305 | struct lock_list root; |
2306 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2307 | |
d7aaba14 ML |
2308 | root.parent = NULL; |
2309 | root.class = hlock_class(this); | |
2310 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2311 | if (ret < 0) |
2312 | return print_bfs_bug(ret); | |
2313 | if (ret == 1) | |
2314 | return ret; | |
fbb9ce95 | 2315 | |
24208ca7 | 2316 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2317 | this, 1, irqclass); |
fbb9ce95 IM |
2318 | } |
2319 | ||
2320 | /* | |
2321 | * Prove that in the backwards-direction subgraph starting at <this> | |
2322 | * there is no lock matching <mask>: | |
2323 | */ | |
2324 | static int | |
2325 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2326 | enum lock_usage_bit bit, const char *irqclass) | |
2327 | { | |
2328 | int ret; | |
d7aaba14 ML |
2329 | struct lock_list root; |
2330 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2331 | |
d7aaba14 ML |
2332 | root.parent = NULL; |
2333 | root.class = hlock_class(this); | |
2334 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2335 | if (ret < 0) |
2336 | return print_bfs_bug(ret); | |
2337 | if (ret == 1) | |
2338 | return ret; | |
fbb9ce95 | 2339 | |
24208ca7 | 2340 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2341 | this, 0, irqclass); |
fbb9ce95 IM |
2342 | } |
2343 | ||
3117df04 | 2344 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2345 | { |
2346 | printk("irq event stamp: %u\n", curr->irq_events); | |
2347 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2348 | print_ip_sym(curr->hardirq_enable_ip); | |
2349 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2350 | print_ip_sym(curr->hardirq_disable_ip); | |
2351 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2352 | print_ip_sym(curr->softirq_enable_ip); | |
2353 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2354 | print_ip_sym(curr->softirq_disable_ip); | |
2355 | } | |
2356 | ||
cd95302d | 2357 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2358 | { |
8e18257d PZ |
2359 | #if HARDIRQ_VERBOSE |
2360 | return class_filter(class); | |
2361 | #endif | |
fbb9ce95 IM |
2362 | return 0; |
2363 | } | |
2364 | ||
cd95302d | 2365 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2366 | { |
8e18257d PZ |
2367 | #if SOFTIRQ_VERBOSE |
2368 | return class_filter(class); | |
2369 | #endif | |
2370 | return 0; | |
fbb9ce95 IM |
2371 | } |
2372 | ||
cd95302d | 2373 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2374 | { |
2375 | #if RECLAIM_VERBOSE | |
2376 | return class_filter(class); | |
2377 | #endif | |
2378 | return 0; | |
2379 | } | |
2380 | ||
fbb9ce95 IM |
2381 | #define STRICT_READ_CHECKS 1 |
2382 | ||
cd95302d PZ |
2383 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2384 | #define LOCKDEP_STATE(__STATE) \ | |
2385 | __STATE##_verbose, | |
2386 | #include "lockdep_states.h" | |
2387 | #undef LOCKDEP_STATE | |
2388 | }; | |
2389 | ||
2390 | static inline int state_verbose(enum lock_usage_bit bit, | |
2391 | struct lock_class *class) | |
2392 | { | |
2393 | return state_verbose_f[bit >> 2](class); | |
2394 | } | |
2395 | ||
42c50d54 PZ |
2396 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2397 | enum lock_usage_bit bit, const char *name); | |
2398 | ||
6a6904d3 | 2399 | static int |
1c21f14e PZ |
2400 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2401 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2402 | { |
f989209e | 2403 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2404 | int read = new_bit & 1; |
42c50d54 PZ |
2405 | int dir = new_bit & 2; |
2406 | ||
38aa2714 PZ |
2407 | /* |
2408 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2409 | * has ENABLED state, which would allow recursion deadlocks. | |
2410 | * | |
2411 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2412 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2413 | */ | |
42c50d54 PZ |
2414 | check_usage_f usage = dir ? |
2415 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2416 | |
38aa2714 PZ |
2417 | /* |
2418 | * Validate that this particular lock does not have conflicting | |
2419 | * usage states. | |
2420 | */ | |
6a6904d3 PZ |
2421 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2422 | return 0; | |
42c50d54 | 2423 | |
38aa2714 PZ |
2424 | /* |
2425 | * Validate that the lock dependencies don't have conflicting usage | |
2426 | * states. | |
2427 | */ | |
2428 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2429 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2430 | return 0; |
780e820b | 2431 | |
38aa2714 PZ |
2432 | /* |
2433 | * Check for read in write conflicts | |
2434 | */ | |
2435 | if (!read) { | |
2436 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2437 | return 0; | |
2438 | ||
2439 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2440 | !usage(curr, this, excl_bit + 1, |
2441 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2442 | return 0; |
2443 | } | |
780e820b | 2444 | |
cd95302d | 2445 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2446 | return 2; |
2447 | ||
2448 | return 1; | |
2449 | } | |
2450 | ||
cf40bd16 | 2451 | enum mark_type { |
36bfb9bb PZ |
2452 | #define LOCKDEP_STATE(__STATE) __STATE, |
2453 | #include "lockdep_states.h" | |
2454 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2455 | }; |
2456 | ||
fbb9ce95 IM |
2457 | /* |
2458 | * Mark all held locks with a usage bit: | |
2459 | */ | |
1d09daa5 | 2460 | static int |
cf40bd16 | 2461 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2462 | { |
2463 | enum lock_usage_bit usage_bit; | |
2464 | struct held_lock *hlock; | |
2465 | int i; | |
2466 | ||
2467 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2468 | hlock = curr->held_locks + i; | |
2469 | ||
cf2ad4d1 PZ |
2470 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2471 | if (hlock->read) | |
2472 | usage_bit += 1; /* READ */ | |
2473 | ||
2474 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2475 | |
70a0686a | 2476 | if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys) |
efbe2eee PZ |
2477 | continue; |
2478 | ||
4ff773bb | 2479 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2480 | return 0; |
2481 | } | |
2482 | ||
2483 | return 1; | |
2484 | } | |
2485 | ||
fbb9ce95 IM |
2486 | /* |
2487 | * Hardirqs will be enabled: | |
2488 | */ | |
dd4e5d3a | 2489 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2490 | { |
2491 | struct task_struct *curr = current; | |
fbb9ce95 | 2492 | |
fbb9ce95 IM |
2493 | /* we'll do an OFF -> ON transition: */ |
2494 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2495 | |
fbb9ce95 IM |
2496 | /* |
2497 | * We are going to turn hardirqs on, so set the | |
2498 | * usage bit for all held locks: | |
2499 | */ | |
cf40bd16 | 2500 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2501 | return; |
2502 | /* | |
2503 | * If we have softirqs enabled, then set the usage | |
2504 | * bit for all held locks. (disabled hardirqs prevented | |
2505 | * this bit from being set before) | |
2506 | */ | |
2507 | if (curr->softirqs_enabled) | |
cf40bd16 | 2508 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2509 | return; |
2510 | ||
8e18257d PZ |
2511 | curr->hardirq_enable_ip = ip; |
2512 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2513 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2514 | } |
dd4e5d3a PZ |
2515 | |
2516 | void trace_hardirqs_on_caller(unsigned long ip) | |
2517 | { | |
2518 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2519 | ||
2520 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2521 | return; | |
2522 | ||
7d36b26b PZ |
2523 | if (unlikely(current->hardirqs_enabled)) { |
2524 | /* | |
2525 | * Neither irq nor preemption are disabled here | |
2526 | * so this is racy by nature but losing one hit | |
2527 | * in a stat is not a big deal. | |
2528 | */ | |
2529 | __debug_atomic_inc(redundant_hardirqs_on); | |
2530 | return; | |
2531 | } | |
2532 | ||
dd4e5d3a PZ |
2533 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2534 | return; | |
2535 | ||
7d36b26b PZ |
2536 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2537 | return; | |
2538 | ||
2539 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2540 | return; | |
2541 | ||
dd4e5d3a PZ |
2542 | current->lockdep_recursion = 1; |
2543 | __trace_hardirqs_on_caller(ip); | |
2544 | current->lockdep_recursion = 0; | |
2545 | } | |
81d68a96 | 2546 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2547 | |
1d09daa5 | 2548 | void trace_hardirqs_on(void) |
81d68a96 SR |
2549 | { |
2550 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2551 | } | |
8e18257d PZ |
2552 | EXPORT_SYMBOL(trace_hardirqs_on); |
2553 | ||
2554 | /* | |
2555 | * Hardirqs were disabled: | |
2556 | */ | |
6afe40b4 | 2557 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2558 | { |
2559 | struct task_struct *curr = current; | |
2560 | ||
6afe40b4 | 2561 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2562 | |
8e18257d PZ |
2563 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2564 | return; | |
2565 | ||
2566 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2567 | return; | |
2568 | ||
2569 | if (curr->hardirqs_enabled) { | |
2570 | /* | |
2571 | * We have done an ON -> OFF transition: | |
2572 | */ | |
2573 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2574 | curr->hardirq_disable_ip = ip; |
8e18257d | 2575 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2576 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2577 | } else |
bd6d29c2 | 2578 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2579 | } |
81d68a96 | 2580 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2581 | |
1d09daa5 | 2582 | void trace_hardirqs_off(void) |
81d68a96 SR |
2583 | { |
2584 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2585 | } | |
8e18257d PZ |
2586 | EXPORT_SYMBOL(trace_hardirqs_off); |
2587 | ||
2588 | /* | |
2589 | * Softirqs will be enabled: | |
2590 | */ | |
2591 | void trace_softirqs_on(unsigned long ip) | |
2592 | { | |
2593 | struct task_struct *curr = current; | |
2594 | ||
dd4e5d3a | 2595 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2596 | return; |
2597 | ||
2598 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2599 | return; | |
2600 | ||
2601 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2602 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2603 | return; |
2604 | } | |
2605 | ||
dd4e5d3a | 2606 | current->lockdep_recursion = 1; |
8e18257d PZ |
2607 | /* |
2608 | * We'll do an OFF -> ON transition: | |
2609 | */ | |
2610 | curr->softirqs_enabled = 1; | |
2611 | curr->softirq_enable_ip = ip; | |
2612 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2613 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2614 | /* |
2615 | * We are going to turn softirqs on, so set the | |
2616 | * usage bit for all held locks, if hardirqs are | |
2617 | * enabled too: | |
2618 | */ | |
2619 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2620 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2621 | current->lockdep_recursion = 0; |
8e18257d PZ |
2622 | } |
2623 | ||
2624 | /* | |
2625 | * Softirqs were disabled: | |
2626 | */ | |
2627 | void trace_softirqs_off(unsigned long ip) | |
2628 | { | |
2629 | struct task_struct *curr = current; | |
2630 | ||
dd4e5d3a | 2631 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2632 | return; |
2633 | ||
2634 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2635 | return; | |
2636 | ||
2637 | if (curr->softirqs_enabled) { | |
2638 | /* | |
2639 | * We have done an ON -> OFF transition: | |
2640 | */ | |
2641 | curr->softirqs_enabled = 0; | |
2642 | curr->softirq_disable_ip = ip; | |
2643 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2644 | debug_atomic_inc(softirqs_off_events); |
8e18257d PZ |
2645 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2646 | } else | |
bd6d29c2 | 2647 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2648 | } |
2649 | ||
2f850181 | 2650 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2651 | { |
2652 | struct task_struct *curr = current; | |
2653 | ||
2654 | if (unlikely(!debug_locks)) | |
2655 | return; | |
2656 | ||
2657 | /* no reclaim without waiting on it */ | |
2658 | if (!(gfp_mask & __GFP_WAIT)) | |
2659 | return; | |
2660 | ||
2661 | /* this guy won't enter reclaim */ | |
2662 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2663 | return; | |
2664 | ||
2665 | /* We're only interested __GFP_FS allocations for now */ | |
2666 | if (!(gfp_mask & __GFP_FS)) | |
2667 | return; | |
2668 | ||
2f850181 | 2669 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2670 | return; |
2671 | ||
2672 | mark_held_locks(curr, RECLAIM_FS); | |
2673 | } | |
2674 | ||
2f850181 PZ |
2675 | static void check_flags(unsigned long flags); |
2676 | ||
2677 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2678 | { | |
2679 | unsigned long flags; | |
2680 | ||
2681 | if (unlikely(current->lockdep_recursion)) | |
2682 | return; | |
2683 | ||
2684 | raw_local_irq_save(flags); | |
2685 | check_flags(flags); | |
2686 | current->lockdep_recursion = 1; | |
2687 | __lockdep_trace_alloc(gfp_mask, flags); | |
2688 | current->lockdep_recursion = 0; | |
2689 | raw_local_irq_restore(flags); | |
2690 | } | |
2691 | ||
8e18257d PZ |
2692 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2693 | { | |
2694 | /* | |
2695 | * If non-trylock use in a hardirq or softirq context, then | |
2696 | * mark the lock as used in these contexts: | |
2697 | */ | |
2698 | if (!hlock->trylock) { | |
2699 | if (hlock->read) { | |
2700 | if (curr->hardirq_context) | |
2701 | if (!mark_lock(curr, hlock, | |
2702 | LOCK_USED_IN_HARDIRQ_READ)) | |
2703 | return 0; | |
2704 | if (curr->softirq_context) | |
2705 | if (!mark_lock(curr, hlock, | |
2706 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2707 | return 0; | |
2708 | } else { | |
2709 | if (curr->hardirq_context) | |
2710 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2711 | return 0; | |
2712 | if (curr->softirq_context) | |
2713 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2714 | return 0; | |
2715 | } | |
2716 | } | |
2717 | if (!hlock->hardirqs_off) { | |
2718 | if (hlock->read) { | |
2719 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2720 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2721 | return 0; |
2722 | if (curr->softirqs_enabled) | |
2723 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2724 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2725 | return 0; |
2726 | } else { | |
2727 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2728 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2729 | return 0; |
2730 | if (curr->softirqs_enabled) | |
2731 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2732 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2733 | return 0; |
2734 | } | |
2735 | } | |
2736 | ||
cf40bd16 NP |
2737 | /* |
2738 | * We reuse the irq context infrastructure more broadly as a general | |
2739 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2740 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2741 | * allocation). | |
2742 | */ | |
2743 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2744 | if (hlock->read) { | |
2745 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2746 | return 0; | |
2747 | } else { | |
2748 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2749 | return 0; | |
2750 | } | |
2751 | } | |
2752 | ||
8e18257d PZ |
2753 | return 1; |
2754 | } | |
2755 | ||
2756 | static int separate_irq_context(struct task_struct *curr, | |
2757 | struct held_lock *hlock) | |
2758 | { | |
2759 | unsigned int depth = curr->lockdep_depth; | |
2760 | ||
2761 | /* | |
2762 | * Keep track of points where we cross into an interrupt context: | |
2763 | */ | |
2764 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2765 | curr->softirq_context; | |
2766 | if (depth) { | |
2767 | struct held_lock *prev_hlock; | |
2768 | ||
2769 | prev_hlock = curr->held_locks + depth-1; | |
2770 | /* | |
2771 | * If we cross into another context, reset the | |
2772 | * hash key (this also prevents the checking and the | |
2773 | * adding of the dependency to 'prev'): | |
2774 | */ | |
2775 | if (prev_hlock->irq_context != hlock->irq_context) | |
2776 | return 1; | |
2777 | } | |
2778 | return 0; | |
fbb9ce95 IM |
2779 | } |
2780 | ||
8e18257d | 2781 | #else |
fbb9ce95 | 2782 | |
8e18257d PZ |
2783 | static inline |
2784 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2785 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2786 | { |
8e18257d PZ |
2787 | WARN_ON(1); |
2788 | return 1; | |
2789 | } | |
fbb9ce95 | 2790 | |
8e18257d PZ |
2791 | static inline int mark_irqflags(struct task_struct *curr, |
2792 | struct held_lock *hlock) | |
2793 | { | |
2794 | return 1; | |
2795 | } | |
fbb9ce95 | 2796 | |
8e18257d PZ |
2797 | static inline int separate_irq_context(struct task_struct *curr, |
2798 | struct held_lock *hlock) | |
2799 | { | |
2800 | return 0; | |
fbb9ce95 IM |
2801 | } |
2802 | ||
868a23a8 PZ |
2803 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2804 | { | |
2805 | } | |
2806 | ||
8e18257d | 2807 | #endif |
fbb9ce95 IM |
2808 | |
2809 | /* | |
8e18257d | 2810 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2811 | */ |
1d09daa5 | 2812 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2813 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2814 | { |
8e18257d | 2815 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2816 | |
2817 | /* | |
8e18257d PZ |
2818 | * If already set then do not dirty the cacheline, |
2819 | * nor do any checks: | |
fbb9ce95 | 2820 | */ |
f82b217e | 2821 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2822 | return 1; |
2823 | ||
2824 | if (!graph_lock()) | |
2825 | return 0; | |
fbb9ce95 | 2826 | /* |
25985edc | 2827 | * Make sure we didn't race: |
fbb9ce95 | 2828 | */ |
f82b217e | 2829 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2830 | graph_unlock(); |
2831 | return 1; | |
2832 | } | |
fbb9ce95 | 2833 | |
f82b217e | 2834 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2835 | |
f82b217e | 2836 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2837 | return 0; |
fbb9ce95 | 2838 | |
8e18257d | 2839 | switch (new_bit) { |
5346417e PZ |
2840 | #define LOCKDEP_STATE(__STATE) \ |
2841 | case LOCK_USED_IN_##__STATE: \ | |
2842 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2843 | case LOCK_ENABLED_##__STATE: \ | |
2844 | case LOCK_ENABLED_##__STATE##_READ: | |
2845 | #include "lockdep_states.h" | |
2846 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2847 | ret = mark_lock_irq(curr, this, new_bit); |
2848 | if (!ret) | |
2849 | return 0; | |
2850 | break; | |
2851 | case LOCK_USED: | |
bd6d29c2 | 2852 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
2853 | break; |
2854 | default: | |
2855 | if (!debug_locks_off_graph_unlock()) | |
2856 | return 0; | |
2857 | WARN_ON(1); | |
2858 | return 0; | |
2859 | } | |
fbb9ce95 | 2860 | |
8e18257d PZ |
2861 | graph_unlock(); |
2862 | ||
2863 | /* | |
2864 | * We must printk outside of the graph_lock: | |
2865 | */ | |
2866 | if (ret == 2) { | |
2867 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2868 | print_lock(this); | |
2869 | print_irqtrace_events(curr); | |
2870 | dump_stack(); | |
2871 | } | |
2872 | ||
2873 | return ret; | |
2874 | } | |
fbb9ce95 IM |
2875 | |
2876 | /* | |
2877 | * Initialize a lock instance's lock-class mapping info: | |
2878 | */ | |
2879 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2880 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2881 | { |
f59de899 | 2882 | memset(lock, 0, sizeof(*lock)); |
62016250 | 2883 | |
c8a25005 PZ |
2884 | #ifdef CONFIG_LOCK_STAT |
2885 | lock->cpu = raw_smp_processor_id(); | |
2886 | #endif | |
2887 | ||
2888 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2889 | lock->name = "NULL"; | |
fbb9ce95 | 2890 | return; |
c8a25005 PZ |
2891 | } |
2892 | ||
2893 | lock->name = name; | |
fbb9ce95 IM |
2894 | |
2895 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2896 | return; | |
fbb9ce95 IM |
2897 | /* |
2898 | * Sanity check, the lock-class key must be persistent: | |
2899 | */ | |
2900 | if (!static_obj(key)) { | |
2901 | printk("BUG: key %p not in .data!\n", key); | |
2902 | DEBUG_LOCKS_WARN_ON(1); | |
2903 | return; | |
2904 | } | |
fbb9ce95 | 2905 | lock->key = key; |
c8a25005 PZ |
2906 | |
2907 | if (unlikely(!debug_locks)) | |
2908 | return; | |
2909 | ||
4dfbb9d8 PZ |
2910 | if (subclass) |
2911 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2912 | } |
fbb9ce95 IM |
2913 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2914 | ||
1704f47b PZ |
2915 | struct lock_class_key __lockdep_no_validate__; |
2916 | ||
fbb9ce95 IM |
2917 | /* |
2918 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2919 | * We maintain the dependency maps and validate the locking attempt: | |
2920 | */ | |
2921 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2922 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
2923 | struct lockdep_map *nest_lock, unsigned long ip, |
2924 | int references) | |
fbb9ce95 IM |
2925 | { |
2926 | struct task_struct *curr = current; | |
d6d897ce | 2927 | struct lock_class *class = NULL; |
fbb9ce95 | 2928 | struct held_lock *hlock; |
fbb9ce95 IM |
2929 | unsigned int depth, id; |
2930 | int chain_head = 0; | |
bb97a91e | 2931 | int class_idx; |
fbb9ce95 IM |
2932 | u64 chain_key; |
2933 | ||
f20786ff PZ |
2934 | if (!prove_locking) |
2935 | check = 1; | |
2936 | ||
fbb9ce95 IM |
2937 | if (unlikely(!debug_locks)) |
2938 | return 0; | |
2939 | ||
2940 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2941 | return 0; | |
2942 | ||
1704f47b PZ |
2943 | if (lock->key == &__lockdep_no_validate__) |
2944 | check = 1; | |
2945 | ||
62016250 HM |
2946 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
2947 | class = lock->class_cache[subclass]; | |
d6d897ce | 2948 | /* |
62016250 | 2949 | * Not cached? |
d6d897ce | 2950 | */ |
fbb9ce95 | 2951 | if (unlikely(!class)) { |
4dfbb9d8 | 2952 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2953 | if (!class) |
2954 | return 0; | |
2955 | } | |
bd6d29c2 | 2956 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
2957 | if (very_verbose(class)) { |
2958 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2959 | if (class->name_version > 1) | |
2960 | printk("#%d", class->name_version); | |
2961 | printk("\n"); | |
2962 | dump_stack(); | |
2963 | } | |
2964 | ||
2965 | /* | |
2966 | * Add the lock to the list of currently held locks. | |
2967 | * (we dont increase the depth just yet, up until the | |
2968 | * dependency checks are done) | |
2969 | */ | |
2970 | depth = curr->lockdep_depth; | |
2971 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2972 | return 0; | |
2973 | ||
bb97a91e PZ |
2974 | class_idx = class - lock_classes + 1; |
2975 | ||
2976 | if (depth) { | |
2977 | hlock = curr->held_locks + depth - 1; | |
2978 | if (hlock->class_idx == class_idx && nest_lock) { | |
2979 | if (hlock->references) | |
2980 | hlock->references++; | |
2981 | else | |
2982 | hlock->references = 2; | |
2983 | ||
2984 | return 1; | |
2985 | } | |
2986 | } | |
2987 | ||
fbb9ce95 | 2988 | hlock = curr->held_locks + depth; |
f82b217e DJ |
2989 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2990 | return 0; | |
bb97a91e | 2991 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
2992 | hlock->acquire_ip = ip; |
2993 | hlock->instance = lock; | |
7531e2f3 | 2994 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2995 | hlock->trylock = trylock; |
2996 | hlock->read = read; | |
2997 | hlock->check = check; | |
6951b12a | 2998 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 2999 | hlock->references = references; |
f20786ff PZ |
3000 | #ifdef CONFIG_LOCK_STAT |
3001 | hlock->waittime_stamp = 0; | |
3365e779 | 3002 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 3003 | #endif |
fbb9ce95 | 3004 | |
8e18257d PZ |
3005 | if (check == 2 && !mark_irqflags(curr, hlock)) |
3006 | return 0; | |
3007 | ||
fbb9ce95 | 3008 | /* mark it as used: */ |
4ff773bb | 3009 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3010 | return 0; |
8e18257d | 3011 | |
fbb9ce95 | 3012 | /* |
17aacfb9 | 3013 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3014 | * lock keys along the dependency chain. We save the hash value |
3015 | * at every step so that we can get the current hash easily | |
3016 | * after unlock. The chain hash is then used to cache dependency | |
3017 | * results. | |
3018 | * | |
3019 | * The 'key ID' is what is the most compact key value to drive | |
3020 | * the hash, not class->key. | |
3021 | */ | |
3022 | id = class - lock_classes; | |
3023 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
3024 | return 0; | |
3025 | ||
3026 | chain_key = curr->curr_chain_key; | |
3027 | if (!depth) { | |
3028 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
3029 | return 0; | |
3030 | chain_head = 1; | |
3031 | } | |
3032 | ||
3033 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3034 | if (separate_irq_context(curr, hlock)) { |
3035 | chain_key = 0; | |
3036 | chain_head = 1; | |
fbb9ce95 | 3037 | } |
fbb9ce95 | 3038 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 3039 | |
3aa416b0 | 3040 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3041 | return 0; |
381a2292 | 3042 | |
3aa416b0 | 3043 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3044 | curr->lockdep_depth++; |
3045 | check_chain_key(curr); | |
60e114d1 JP |
3046 | #ifdef CONFIG_DEBUG_LOCKDEP |
3047 | if (unlikely(!debug_locks)) | |
3048 | return 0; | |
3049 | #endif | |
fbb9ce95 IM |
3050 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3051 | debug_locks_off(); | |
3052 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
3053 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 3054 | dump_stack(); |
fbb9ce95 IM |
3055 | return 0; |
3056 | } | |
381a2292 | 3057 | |
fbb9ce95 IM |
3058 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3059 | max_lockdep_depth = curr->lockdep_depth; | |
3060 | ||
3061 | return 1; | |
3062 | } | |
3063 | ||
3064 | static int | |
3065 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3066 | unsigned long ip) | |
3067 | { | |
3068 | if (!debug_locks_off()) | |
3069 | return 0; | |
3070 | if (debug_locks_silent) | |
3071 | return 0; | |
3072 | ||
b3fbab05 PM |
3073 | printk("\n"); |
3074 | printk("=====================================\n"); | |
3075 | printk("[ BUG: bad unlock balance detected! ]\n"); | |
3076 | printk("-------------------------------------\n"); | |
fbb9ce95 | 3077 | printk("%s/%d is trying to release lock (", |
ba25f9dc | 3078 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3079 | print_lockdep_cache(lock); |
3080 | printk(") at:\n"); | |
3081 | print_ip_sym(ip); | |
3082 | printk("but there are no more locks to release!\n"); | |
3083 | printk("\nother info that might help us debug this:\n"); | |
3084 | lockdep_print_held_locks(curr); | |
3085 | ||
3086 | printk("\nstack backtrace:\n"); | |
3087 | dump_stack(); | |
3088 | ||
3089 | return 0; | |
3090 | } | |
3091 | ||
3092 | /* | |
3093 | * Common debugging checks for both nested and non-nested unlock: | |
3094 | */ | |
3095 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
3096 | unsigned long ip) | |
3097 | { | |
3098 | if (unlikely(!debug_locks)) | |
3099 | return 0; | |
3100 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
3101 | return 0; | |
3102 | ||
3103 | if (curr->lockdep_depth <= 0) | |
3104 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3105 | ||
3106 | return 1; | |
3107 | } | |
3108 | ||
bb97a91e PZ |
3109 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3110 | { | |
3111 | if (hlock->instance == lock) | |
3112 | return 1; | |
3113 | ||
3114 | if (hlock->references) { | |
62016250 | 3115 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3116 | |
3117 | if (!class) | |
3118 | class = look_up_lock_class(lock, 0); | |
3119 | ||
80e0401e PZ |
3120 | /* |
3121 | * If look_up_lock_class() failed to find a class, we're trying | |
3122 | * to test if we hold a lock that has never yet been acquired. | |
3123 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3124 | * holding it either, so report failure. | |
3125 | */ | |
3126 | if (!class) | |
bb97a91e PZ |
3127 | return 0; |
3128 | ||
3129 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) | |
3130 | return 0; | |
3131 | ||
3132 | if (hlock->class_idx == class - lock_classes + 1) | |
3133 | return 1; | |
3134 | } | |
3135 | ||
3136 | return 0; | |
3137 | } | |
3138 | ||
64aa348e | 3139 | static int |
00ef9f73 PZ |
3140 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3141 | struct lock_class_key *key, unsigned int subclass, | |
3142 | unsigned long ip) | |
64aa348e PZ |
3143 | { |
3144 | struct task_struct *curr = current; | |
3145 | struct held_lock *hlock, *prev_hlock; | |
3146 | struct lock_class *class; | |
3147 | unsigned int depth; | |
3148 | int i; | |
3149 | ||
3150 | depth = curr->lockdep_depth; | |
3151 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3152 | return 0; | |
3153 | ||
3154 | prev_hlock = NULL; | |
3155 | for (i = depth-1; i >= 0; i--) { | |
3156 | hlock = curr->held_locks + i; | |
3157 | /* | |
3158 | * We must not cross into another context: | |
3159 | */ | |
3160 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3161 | break; | |
bb97a91e | 3162 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3163 | goto found_it; |
3164 | prev_hlock = hlock; | |
3165 | } | |
3166 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3167 | ||
3168 | found_it: | |
00ef9f73 | 3169 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3170 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3171 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3172 | |
3173 | curr->lockdep_depth = i; | |
3174 | curr->curr_chain_key = hlock->prev_chain_key; | |
3175 | ||
3176 | for (; i < depth; i++) { | |
3177 | hlock = curr->held_locks + i; | |
3178 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3179 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3180 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3181 | hlock->nest_lock, hlock->acquire_ip, |
3182 | hlock->references)) | |
64aa348e PZ |
3183 | return 0; |
3184 | } | |
3185 | ||
3186 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
3187 | return 0; | |
3188 | return 1; | |
3189 | } | |
3190 | ||
fbb9ce95 IM |
3191 | /* |
3192 | * Remove the lock to the list of currently held locks in a | |
3193 | * potentially non-nested (out of order) manner. This is a | |
3194 | * relatively rare operation, as all the unlock APIs default | |
3195 | * to nested mode (which uses lock_release()): | |
3196 | */ | |
3197 | static int | |
3198 | lock_release_non_nested(struct task_struct *curr, | |
3199 | struct lockdep_map *lock, unsigned long ip) | |
3200 | { | |
3201 | struct held_lock *hlock, *prev_hlock; | |
3202 | unsigned int depth; | |
3203 | int i; | |
3204 | ||
3205 | /* | |
3206 | * Check whether the lock exists in the current stack | |
3207 | * of held locks: | |
3208 | */ | |
3209 | depth = curr->lockdep_depth; | |
3210 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3211 | return 0; | |
3212 | ||
3213 | prev_hlock = NULL; | |
3214 | for (i = depth-1; i >= 0; i--) { | |
3215 | hlock = curr->held_locks + i; | |
3216 | /* | |
3217 | * We must not cross into another context: | |
3218 | */ | |
3219 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3220 | break; | |
bb97a91e | 3221 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3222 | goto found_it; |
3223 | prev_hlock = hlock; | |
3224 | } | |
3225 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3226 | ||
3227 | found_it: | |
bb97a91e PZ |
3228 | if (hlock->instance == lock) |
3229 | lock_release_holdtime(hlock); | |
3230 | ||
3231 | if (hlock->references) { | |
3232 | hlock->references--; | |
3233 | if (hlock->references) { | |
3234 | /* | |
3235 | * We had, and after removing one, still have | |
3236 | * references, the current lock stack is still | |
3237 | * valid. We're done! | |
3238 | */ | |
3239 | return 1; | |
3240 | } | |
3241 | } | |
f20786ff | 3242 | |
fbb9ce95 IM |
3243 | /* |
3244 | * We have the right lock to unlock, 'hlock' points to it. | |
3245 | * Now we remove it from the stack, and add back the other | |
3246 | * entries (if any), recalculating the hash along the way: | |
3247 | */ | |
bb97a91e | 3248 | |
fbb9ce95 IM |
3249 | curr->lockdep_depth = i; |
3250 | curr->curr_chain_key = hlock->prev_chain_key; | |
3251 | ||
3252 | for (i++; i < depth; i++) { | |
3253 | hlock = curr->held_locks + i; | |
3254 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3255 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3256 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3257 | hlock->nest_lock, hlock->acquire_ip, |
3258 | hlock->references)) | |
fbb9ce95 IM |
3259 | return 0; |
3260 | } | |
3261 | ||
3262 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
3263 | return 0; | |
3264 | return 1; | |
3265 | } | |
3266 | ||
3267 | /* | |
3268 | * Remove the lock to the list of currently held locks - this gets | |
3269 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3270 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3271 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3272 | */ | |
3273 | static int lock_release_nested(struct task_struct *curr, | |
3274 | struct lockdep_map *lock, unsigned long ip) | |
3275 | { | |
3276 | struct held_lock *hlock; | |
3277 | unsigned int depth; | |
3278 | ||
3279 | /* | |
3280 | * Pop off the top of the lock stack: | |
3281 | */ | |
3282 | depth = curr->lockdep_depth - 1; | |
3283 | hlock = curr->held_locks + depth; | |
3284 | ||
3285 | /* | |
3286 | * Is the unlock non-nested: | |
3287 | */ | |
bb97a91e | 3288 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3289 | return lock_release_non_nested(curr, lock, ip); |
3290 | curr->lockdep_depth--; | |
3291 | ||
3292 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
3293 | return 0; | |
3294 | ||
3295 | curr->curr_chain_key = hlock->prev_chain_key; | |
3296 | ||
f20786ff PZ |
3297 | lock_release_holdtime(hlock); |
3298 | ||
fbb9ce95 IM |
3299 | #ifdef CONFIG_DEBUG_LOCKDEP |
3300 | hlock->prev_chain_key = 0; | |
f82b217e | 3301 | hlock->class_idx = 0; |
fbb9ce95 IM |
3302 | hlock->acquire_ip = 0; |
3303 | hlock->irq_context = 0; | |
3304 | #endif | |
3305 | return 1; | |
3306 | } | |
3307 | ||
3308 | /* | |
3309 | * Remove the lock to the list of currently held locks - this gets | |
3310 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3311 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3312 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3313 | */ | |
3314 | static void | |
3315 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3316 | { | |
3317 | struct task_struct *curr = current; | |
3318 | ||
3319 | if (!check_unlock(curr, lock, ip)) | |
3320 | return; | |
3321 | ||
3322 | if (nested) { | |
3323 | if (!lock_release_nested(curr, lock, ip)) | |
3324 | return; | |
3325 | } else { | |
3326 | if (!lock_release_non_nested(curr, lock, ip)) | |
3327 | return; | |
3328 | } | |
3329 | ||
3330 | check_chain_key(curr); | |
3331 | } | |
3332 | ||
f607c668 PZ |
3333 | static int __lock_is_held(struct lockdep_map *lock) |
3334 | { | |
3335 | struct task_struct *curr = current; | |
3336 | int i; | |
3337 | ||
3338 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3339 | struct held_lock *hlock = curr->held_locks + i; |
3340 | ||
3341 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3342 | return 1; |
3343 | } | |
3344 | ||
3345 | return 0; | |
3346 | } | |
3347 | ||
fbb9ce95 IM |
3348 | /* |
3349 | * Check whether we follow the irq-flags state precisely: | |
3350 | */ | |
1d09daa5 | 3351 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3352 | { |
992860e9 IM |
3353 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3354 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3355 | if (!debug_locks) |
3356 | return; | |
3357 | ||
5f9fa8a6 IM |
3358 | if (irqs_disabled_flags(flags)) { |
3359 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3360 | printk("possible reason: unannotated irqs-off.\n"); | |
3361 | } | |
3362 | } else { | |
3363 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3364 | printk("possible reason: unannotated irqs-on.\n"); | |
3365 | } | |
3366 | } | |
fbb9ce95 IM |
3367 | |
3368 | /* | |
3369 | * We dont accurately track softirq state in e.g. | |
3370 | * hardirq contexts (such as on 4KSTACKS), so only | |
3371 | * check if not in hardirq contexts: | |
3372 | */ | |
3373 | if (!hardirq_count()) { | |
3374 | if (softirq_count()) | |
3375 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3376 | else | |
3377 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3378 | } | |
3379 | ||
3380 | if (!debug_locks) | |
3381 | print_irqtrace_events(current); | |
3382 | #endif | |
3383 | } | |
3384 | ||
00ef9f73 PZ |
3385 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3386 | struct lock_class_key *key, unsigned int subclass, | |
3387 | unsigned long ip) | |
64aa348e PZ |
3388 | { |
3389 | unsigned long flags; | |
3390 | ||
3391 | if (unlikely(current->lockdep_recursion)) | |
3392 | return; | |
3393 | ||
3394 | raw_local_irq_save(flags); | |
3395 | current->lockdep_recursion = 1; | |
3396 | check_flags(flags); | |
00ef9f73 | 3397 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3398 | check_chain_key(current); |
3399 | current->lockdep_recursion = 0; | |
3400 | raw_local_irq_restore(flags); | |
3401 | } | |
00ef9f73 | 3402 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3403 | |
fbb9ce95 IM |
3404 | /* |
3405 | * We are not always called with irqs disabled - do that here, | |
3406 | * and also avoid lockdep recursion: | |
3407 | */ | |
1d09daa5 | 3408 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3409 | int trylock, int read, int check, |
3410 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3411 | { |
3412 | unsigned long flags; | |
3413 | ||
3414 | if (unlikely(current->lockdep_recursion)) | |
3415 | return; | |
3416 | ||
3417 | raw_local_irq_save(flags); | |
3418 | check_flags(flags); | |
3419 | ||
3420 | current->lockdep_recursion = 1; | |
db2c4c77 | 3421 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3422 | __lock_acquire(lock, subclass, trylock, read, check, |
bb97a91e | 3423 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3424 | current->lockdep_recursion = 0; |
3425 | raw_local_irq_restore(flags); | |
3426 | } | |
fbb9ce95 IM |
3427 | EXPORT_SYMBOL_GPL(lock_acquire); |
3428 | ||
1d09daa5 | 3429 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3430 | unsigned long ip) |
fbb9ce95 IM |
3431 | { |
3432 | unsigned long flags; | |
3433 | ||
3434 | if (unlikely(current->lockdep_recursion)) | |
3435 | return; | |
3436 | ||
3437 | raw_local_irq_save(flags); | |
3438 | check_flags(flags); | |
3439 | current->lockdep_recursion = 1; | |
93135439 | 3440 | trace_lock_release(lock, ip); |
fbb9ce95 IM |
3441 | __lock_release(lock, nested, ip); |
3442 | current->lockdep_recursion = 0; | |
3443 | raw_local_irq_restore(flags); | |
3444 | } | |
fbb9ce95 IM |
3445 | EXPORT_SYMBOL_GPL(lock_release); |
3446 | ||
f607c668 PZ |
3447 | int lock_is_held(struct lockdep_map *lock) |
3448 | { | |
3449 | unsigned long flags; | |
3450 | int ret = 0; | |
3451 | ||
3452 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3453 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3454 | |
3455 | raw_local_irq_save(flags); | |
3456 | check_flags(flags); | |
3457 | ||
3458 | current->lockdep_recursion = 1; | |
3459 | ret = __lock_is_held(lock); | |
3460 | current->lockdep_recursion = 0; | |
3461 | raw_local_irq_restore(flags); | |
3462 | ||
3463 | return ret; | |
3464 | } | |
3465 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3466 | ||
cf40bd16 NP |
3467 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3468 | { | |
3469 | current->lockdep_reclaim_gfp = gfp_mask; | |
3470 | } | |
3471 | ||
3472 | void lockdep_clear_current_reclaim_state(void) | |
3473 | { | |
3474 | current->lockdep_reclaim_gfp = 0; | |
3475 | } | |
3476 | ||
f20786ff PZ |
3477 | #ifdef CONFIG_LOCK_STAT |
3478 | static int | |
3479 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3480 | unsigned long ip) | |
3481 | { | |
3482 | if (!debug_locks_off()) | |
3483 | return 0; | |
3484 | if (debug_locks_silent) | |
3485 | return 0; | |
3486 | ||
b3fbab05 PM |
3487 | printk("\n"); |
3488 | printk("=================================\n"); | |
3489 | printk("[ BUG: bad contention detected! ]\n"); | |
3490 | printk("---------------------------------\n"); | |
f20786ff | 3491 | printk("%s/%d is trying to contend lock (", |
ba25f9dc | 3492 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3493 | print_lockdep_cache(lock); |
3494 | printk(") at:\n"); | |
3495 | print_ip_sym(ip); | |
3496 | printk("but there are no locks held!\n"); | |
3497 | printk("\nother info that might help us debug this:\n"); | |
3498 | lockdep_print_held_locks(curr); | |
3499 | ||
3500 | printk("\nstack backtrace:\n"); | |
3501 | dump_stack(); | |
3502 | ||
3503 | return 0; | |
3504 | } | |
3505 | ||
3506 | static void | |
3507 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3508 | { | |
3509 | struct task_struct *curr = current; | |
3510 | struct held_lock *hlock, *prev_hlock; | |
3511 | struct lock_class_stats *stats; | |
3512 | unsigned int depth; | |
c7e78cff | 3513 | int i, contention_point, contending_point; |
f20786ff PZ |
3514 | |
3515 | depth = curr->lockdep_depth; | |
3516 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3517 | return; | |
3518 | ||
3519 | prev_hlock = NULL; | |
3520 | for (i = depth-1; i >= 0; i--) { | |
3521 | hlock = curr->held_locks + i; | |
3522 | /* | |
3523 | * We must not cross into another context: | |
3524 | */ | |
3525 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3526 | break; | |
bb97a91e | 3527 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3528 | goto found_it; |
3529 | prev_hlock = hlock; | |
3530 | } | |
3531 | print_lock_contention_bug(curr, lock, ip); | |
3532 | return; | |
3533 | ||
3534 | found_it: | |
bb97a91e PZ |
3535 | if (hlock->instance != lock) |
3536 | return; | |
3537 | ||
3365e779 | 3538 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3539 | |
c7e78cff PZ |
3540 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3541 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3542 | lock->ip); | |
f20786ff | 3543 | |
f82b217e | 3544 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3545 | if (contention_point < LOCKSTAT_POINTS) |
3546 | stats->contention_point[contention_point]++; | |
3547 | if (contending_point < LOCKSTAT_POINTS) | |
3548 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3549 | if (lock->cpu != smp_processor_id()) |
3550 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3551 | put_lock_stats(stats); |
3552 | } | |
3553 | ||
3554 | static void | |
c7e78cff | 3555 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3556 | { |
3557 | struct task_struct *curr = current; | |
3558 | struct held_lock *hlock, *prev_hlock; | |
3559 | struct lock_class_stats *stats; | |
3560 | unsigned int depth; | |
3365e779 | 3561 | u64 now, waittime = 0; |
96645678 | 3562 | int i, cpu; |
f20786ff PZ |
3563 | |
3564 | depth = curr->lockdep_depth; | |
3565 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3566 | return; | |
3567 | ||
3568 | prev_hlock = NULL; | |
3569 | for (i = depth-1; i >= 0; i--) { | |
3570 | hlock = curr->held_locks + i; | |
3571 | /* | |
3572 | * We must not cross into another context: | |
3573 | */ | |
3574 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3575 | break; | |
bb97a91e | 3576 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3577 | goto found_it; |
3578 | prev_hlock = hlock; | |
3579 | } | |
3580 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3581 | return; | |
3582 | ||
3583 | found_it: | |
bb97a91e PZ |
3584 | if (hlock->instance != lock) |
3585 | return; | |
3586 | ||
96645678 PZ |
3587 | cpu = smp_processor_id(); |
3588 | if (hlock->waittime_stamp) { | |
3365e779 | 3589 | now = lockstat_clock(); |
96645678 PZ |
3590 | waittime = now - hlock->waittime_stamp; |
3591 | hlock->holdtime_stamp = now; | |
3592 | } | |
f20786ff | 3593 | |
883a2a31 | 3594 | trace_lock_acquired(lock, ip); |
2062501a | 3595 | |
f82b217e | 3596 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3597 | if (waittime) { |
3598 | if (hlock->read) | |
3599 | lock_time_inc(&stats->read_waittime, waittime); | |
3600 | else | |
3601 | lock_time_inc(&stats->write_waittime, waittime); | |
3602 | } | |
3603 | if (lock->cpu != cpu) | |
3604 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3605 | put_lock_stats(stats); |
96645678 PZ |
3606 | |
3607 | lock->cpu = cpu; | |
c7e78cff | 3608 | lock->ip = ip; |
f20786ff PZ |
3609 | } |
3610 | ||
3611 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3612 | { | |
3613 | unsigned long flags; | |
3614 | ||
3615 | if (unlikely(!lock_stat)) | |
3616 | return; | |
3617 | ||
3618 | if (unlikely(current->lockdep_recursion)) | |
3619 | return; | |
3620 | ||
3621 | raw_local_irq_save(flags); | |
3622 | check_flags(flags); | |
3623 | current->lockdep_recursion = 1; | |
db2c4c77 | 3624 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3625 | __lock_contended(lock, ip); |
3626 | current->lockdep_recursion = 0; | |
3627 | raw_local_irq_restore(flags); | |
3628 | } | |
3629 | EXPORT_SYMBOL_GPL(lock_contended); | |
3630 | ||
c7e78cff | 3631 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3632 | { |
3633 | unsigned long flags; | |
3634 | ||
3635 | if (unlikely(!lock_stat)) | |
3636 | return; | |
3637 | ||
3638 | if (unlikely(current->lockdep_recursion)) | |
3639 | return; | |
3640 | ||
3641 | raw_local_irq_save(flags); | |
3642 | check_flags(flags); | |
3643 | current->lockdep_recursion = 1; | |
c7e78cff | 3644 | __lock_acquired(lock, ip); |
f20786ff PZ |
3645 | current->lockdep_recursion = 0; |
3646 | raw_local_irq_restore(flags); | |
3647 | } | |
3648 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3649 | #endif | |
3650 | ||
fbb9ce95 IM |
3651 | /* |
3652 | * Used by the testsuite, sanitize the validator state | |
3653 | * after a simulated failure: | |
3654 | */ | |
3655 | ||
3656 | void lockdep_reset(void) | |
3657 | { | |
3658 | unsigned long flags; | |
23d95a03 | 3659 | int i; |
fbb9ce95 IM |
3660 | |
3661 | raw_local_irq_save(flags); | |
3662 | current->curr_chain_key = 0; | |
3663 | current->lockdep_depth = 0; | |
3664 | current->lockdep_recursion = 0; | |
3665 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3666 | nr_hardirq_chains = 0; | |
3667 | nr_softirq_chains = 0; | |
3668 | nr_process_chains = 0; | |
3669 | debug_locks = 1; | |
23d95a03 IM |
3670 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3671 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3672 | raw_local_irq_restore(flags); |
3673 | } | |
3674 | ||
3675 | static void zap_class(struct lock_class *class) | |
3676 | { | |
3677 | int i; | |
3678 | ||
3679 | /* | |
3680 | * Remove all dependencies this lock is | |
3681 | * involved in: | |
3682 | */ | |
3683 | for (i = 0; i < nr_list_entries; i++) { | |
3684 | if (list_entries[i].class == class) | |
3685 | list_del_rcu(&list_entries[i].entry); | |
3686 | } | |
3687 | /* | |
3688 | * Unhash the class and remove it from the all_lock_classes list: | |
3689 | */ | |
3690 | list_del_rcu(&class->hash_entry); | |
3691 | list_del_rcu(&class->lock_entry); | |
3692 | ||
8bfe0298 | 3693 | class->key = NULL; |
fbb9ce95 IM |
3694 | } |
3695 | ||
fabe874a | 3696 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3697 | { |
3698 | return addr >= start && addr < start + size; | |
3699 | } | |
3700 | ||
3701 | void lockdep_free_key_range(void *start, unsigned long size) | |
3702 | { | |
3703 | struct lock_class *class, *next; | |
3704 | struct list_head *head; | |
3705 | unsigned long flags; | |
3706 | int i; | |
5a26db5b | 3707 | int locked; |
fbb9ce95 IM |
3708 | |
3709 | raw_local_irq_save(flags); | |
5a26db5b | 3710 | locked = graph_lock(); |
fbb9ce95 IM |
3711 | |
3712 | /* | |
3713 | * Unhash all classes that were created by this module: | |
3714 | */ | |
3715 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3716 | head = classhash_table + i; | |
3717 | if (list_empty(head)) | |
3718 | continue; | |
fabe874a | 3719 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3720 | if (within(class->key, start, size)) |
3721 | zap_class(class); | |
fabe874a AV |
3722 | else if (within(class->name, start, size)) |
3723 | zap_class(class); | |
3724 | } | |
fbb9ce95 IM |
3725 | } |
3726 | ||
5a26db5b NP |
3727 | if (locked) |
3728 | graph_unlock(); | |
fbb9ce95 IM |
3729 | raw_local_irq_restore(flags); |
3730 | } | |
3731 | ||
3732 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3733 | { | |
d6d897ce | 3734 | struct lock_class *class, *next; |
fbb9ce95 IM |
3735 | struct list_head *head; |
3736 | unsigned long flags; | |
3737 | int i, j; | |
5a26db5b | 3738 | int locked; |
fbb9ce95 IM |
3739 | |
3740 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3741 | |
3742 | /* | |
d6d897ce IM |
3743 | * Remove all classes this lock might have: |
3744 | */ | |
3745 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3746 | /* | |
3747 | * If the class exists we look it up and zap it: | |
3748 | */ | |
3749 | class = look_up_lock_class(lock, j); | |
3750 | if (class) | |
3751 | zap_class(class); | |
3752 | } | |
3753 | /* | |
3754 | * Debug check: in the end all mapped classes should | |
3755 | * be gone. | |
fbb9ce95 | 3756 | */ |
5a26db5b | 3757 | locked = graph_lock(); |
fbb9ce95 IM |
3758 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3759 | head = classhash_table + i; | |
3760 | if (list_empty(head)) | |
3761 | continue; | |
3762 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
62016250 HM |
3763 | int match = 0; |
3764 | ||
3765 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
3766 | match |= class == lock->class_cache[j]; | |
3767 | ||
3768 | if (unlikely(match)) { | |
74c383f1 IM |
3769 | if (debug_locks_off_graph_unlock()) |
3770 | WARN_ON(1); | |
d6d897ce | 3771 | goto out_restore; |
fbb9ce95 IM |
3772 | } |
3773 | } | |
3774 | } | |
5a26db5b NP |
3775 | if (locked) |
3776 | graph_unlock(); | |
d6d897ce IM |
3777 | |
3778 | out_restore: | |
fbb9ce95 IM |
3779 | raw_local_irq_restore(flags); |
3780 | } | |
3781 | ||
1499993c | 3782 | void lockdep_init(void) |
fbb9ce95 IM |
3783 | { |
3784 | int i; | |
3785 | ||
3786 | /* | |
3787 | * Some architectures have their own start_kernel() | |
3788 | * code which calls lockdep_init(), while we also | |
3789 | * call lockdep_init() from the start_kernel() itself, | |
3790 | * and we want to initialize the hashes only once: | |
3791 | */ | |
3792 | if (lockdep_initialized) | |
3793 | return; | |
3794 | ||
3795 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3796 | INIT_LIST_HEAD(classhash_table + i); | |
3797 | ||
3798 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3799 | INIT_LIST_HEAD(chainhash_table + i); | |
3800 | ||
3801 | lockdep_initialized = 1; | |
3802 | } | |
3803 | ||
3804 | void __init lockdep_info(void) | |
3805 | { | |
3806 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3807 | ||
b0788caf | 3808 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3809 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3810 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3811 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3812 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3813 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3814 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3815 | ||
3816 | printk(" memory used by lock dependency info: %lu kB\n", | |
3817 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3818 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3819 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3820 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 3821 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 3822 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 3823 | + sizeof(struct circular_queue) |
4dd861d6 | 3824 | #endif |
90629209 | 3825 | ) / 1024 |
4dd861d6 | 3826 | ); |
fbb9ce95 IM |
3827 | |
3828 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3829 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3830 | ||
3831 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3832 | if (lockdep_init_error) { |
3833 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3834 | printk("Call stack leading to lockdep invocation was:\n"); | |
3835 | print_stack_trace(&lockdep_init_trace, 0); | |
3836 | } | |
fbb9ce95 IM |
3837 | #endif |
3838 | } | |
3839 | ||
fbb9ce95 IM |
3840 | static void |
3841 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3842 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3843 | { |
3844 | if (!debug_locks_off()) | |
3845 | return; | |
3846 | if (debug_locks_silent) | |
3847 | return; | |
3848 | ||
b3fbab05 PM |
3849 | printk("\n"); |
3850 | printk("=========================\n"); | |
3851 | printk("[ BUG: held lock freed! ]\n"); | |
3852 | printk("-------------------------\n"); | |
fbb9ce95 | 3853 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
ba25f9dc | 3854 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3855 | print_lock(hlock); |
fbb9ce95 IM |
3856 | lockdep_print_held_locks(curr); |
3857 | ||
3858 | printk("\nstack backtrace:\n"); | |
3859 | dump_stack(); | |
3860 | } | |
3861 | ||
54561783 ON |
3862 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3863 | const void* lock_from, unsigned long lock_len) | |
3864 | { | |
3865 | return lock_from + lock_len <= mem_from || | |
3866 | mem_from + mem_len <= lock_from; | |
3867 | } | |
3868 | ||
fbb9ce95 IM |
3869 | /* |
3870 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3871 | * is destroyed or reinitialized - this code checks whether there is | |
3872 | * any held lock in the memory range of <from> to <to>: | |
3873 | */ | |
3874 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3875 | { | |
fbb9ce95 IM |
3876 | struct task_struct *curr = current; |
3877 | struct held_lock *hlock; | |
3878 | unsigned long flags; | |
3879 | int i; | |
3880 | ||
3881 | if (unlikely(!debug_locks)) | |
3882 | return; | |
3883 | ||
3884 | local_irq_save(flags); | |
3885 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3886 | hlock = curr->held_locks + i; | |
3887 | ||
54561783 ON |
3888 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3889 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3890 | continue; |
3891 | ||
54561783 | 3892 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3893 | break; |
3894 | } | |
3895 | local_irq_restore(flags); | |
3896 | } | |
ed07536e | 3897 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3898 | |
3899 | static void print_held_locks_bug(struct task_struct *curr) | |
3900 | { | |
3901 | if (!debug_locks_off()) | |
3902 | return; | |
3903 | if (debug_locks_silent) | |
3904 | return; | |
3905 | ||
b3fbab05 PM |
3906 | printk("\n"); |
3907 | printk("=====================================\n"); | |
3908 | printk("[ BUG: lock held at task exit time! ]\n"); | |
3909 | printk("-------------------------------------\n"); | |
fbb9ce95 | 3910 | printk("%s/%d is exiting with locks still held!\n", |
ba25f9dc | 3911 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3912 | lockdep_print_held_locks(curr); |
3913 | ||
3914 | printk("\nstack backtrace:\n"); | |
3915 | dump_stack(); | |
3916 | } | |
3917 | ||
3918 | void debug_check_no_locks_held(struct task_struct *task) | |
3919 | { | |
3920 | if (unlikely(task->lockdep_depth > 0)) | |
3921 | print_held_locks_bug(task); | |
3922 | } | |
3923 | ||
3924 | void debug_show_all_locks(void) | |
3925 | { | |
3926 | struct task_struct *g, *p; | |
3927 | int count = 10; | |
3928 | int unlock = 1; | |
3929 | ||
9c35dd7f JP |
3930 | if (unlikely(!debug_locks)) { |
3931 | printk("INFO: lockdep is turned off.\n"); | |
3932 | return; | |
3933 | } | |
fbb9ce95 IM |
3934 | printk("\nShowing all locks held in the system:\n"); |
3935 | ||
3936 | /* | |
3937 | * Here we try to get the tasklist_lock as hard as possible, | |
3938 | * if not successful after 2 seconds we ignore it (but keep | |
3939 | * trying). This is to enable a debug printout even if a | |
3940 | * tasklist_lock-holding task deadlocks or crashes. | |
3941 | */ | |
3942 | retry: | |
3943 | if (!read_trylock(&tasklist_lock)) { | |
3944 | if (count == 10) | |
3945 | printk("hm, tasklist_lock locked, retrying... "); | |
3946 | if (count) { | |
3947 | count--; | |
3948 | printk(" #%d", 10-count); | |
3949 | mdelay(200); | |
3950 | goto retry; | |
3951 | } | |
3952 | printk(" ignoring it.\n"); | |
3953 | unlock = 0; | |
46fec7ac | 3954 | } else { |
3955 | if (count != 10) | |
3956 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3957 | } |
fbb9ce95 IM |
3958 | |
3959 | do_each_thread(g, p) { | |
85684873 IM |
3960 | /* |
3961 | * It's not reliable to print a task's held locks | |
3962 | * if it's not sleeping (or if it's not the current | |
3963 | * task): | |
3964 | */ | |
3965 | if (p->state == TASK_RUNNING && p != current) | |
3966 | continue; | |
fbb9ce95 IM |
3967 | if (p->lockdep_depth) |
3968 | lockdep_print_held_locks(p); | |
3969 | if (!unlock) | |
3970 | if (read_trylock(&tasklist_lock)) | |
3971 | unlock = 1; | |
3972 | } while_each_thread(g, p); | |
3973 | ||
3974 | printk("\n"); | |
3975 | printk("=============================================\n\n"); | |
3976 | ||
3977 | if (unlock) | |
3978 | read_unlock(&tasklist_lock); | |
3979 | } | |
fbb9ce95 IM |
3980 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3981 | ||
82a1fcb9 IM |
3982 | /* |
3983 | * Careful: only use this function if you are sure that | |
3984 | * the task cannot run in parallel! | |
3985 | */ | |
f1b499f0 | 3986 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 3987 | { |
9c35dd7f JP |
3988 | if (unlikely(!debug_locks)) { |
3989 | printk("INFO: lockdep is turned off.\n"); | |
3990 | return; | |
3991 | } | |
fbb9ce95 IM |
3992 | lockdep_print_held_locks(task); |
3993 | } | |
fbb9ce95 | 3994 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3995 | |
3996 | void lockdep_sys_exit(void) | |
3997 | { | |
3998 | struct task_struct *curr = current; | |
3999 | ||
4000 | if (unlikely(curr->lockdep_depth)) { | |
4001 | if (!debug_locks_off()) | |
4002 | return; | |
b3fbab05 PM |
4003 | printk("\n"); |
4004 | printk("================================================\n"); | |
4005 | printk("[ BUG: lock held when returning to user space! ]\n"); | |
4006 | printk("------------------------------------------------\n"); | |
b351d164 PZ |
4007 | printk("%s/%d is leaving the kernel with locks still held!\n", |
4008 | curr->comm, curr->pid); | |
4009 | lockdep_print_held_locks(curr); | |
4010 | } | |
4011 | } | |
0632eb3d | 4012 | |
b3fbab05 | 4013 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
0632eb3d PM |
4014 | { |
4015 | struct task_struct *curr = current; | |
4016 | ||
2b3fc35f | 4017 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4018 | if (!debug_locks_off()) |
4019 | return; | |
2b3fc35f LJ |
4020 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4021 | /* Note: the following can be executed concurrently, so be careful. */ | |
b3fbab05 PM |
4022 | printk("\n"); |
4023 | printk("===============================\n"); | |
4024 | printk("[ INFO: suspicious RCU usage. ]\n"); | |
4025 | printk("-------------------------------\n"); | |
4026 | printk("%s:%d %s!\n", file, line, s); | |
0632eb3d | 4027 | printk("\nother info that might help us debug this:\n\n"); |
cc5b83a9 | 4028 | printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks); |
0632eb3d PM |
4029 | lockdep_print_held_locks(curr); |
4030 | printk("\nstack backtrace:\n"); | |
4031 | dump_stack(); | |
4032 | } | |
b3fbab05 | 4033 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |