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Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
af012961 | 47 | |
fbb9ce95 IM |
48 | #include <asm/sections.h> |
49 | ||
50 | #include "lockdep_internals.h" | |
51 | ||
a8d154b0 | 52 | #define CREATE_TRACE_POINTS |
67178767 | 53 | #include <trace/events/lock.h> |
a8d154b0 | 54 | |
f20786ff PZ |
55 | #ifdef CONFIG_PROVE_LOCKING |
56 | int prove_locking = 1; | |
57 | module_param(prove_locking, int, 0644); | |
58 | #else | |
59 | #define prove_locking 0 | |
60 | #endif | |
61 | ||
62 | #ifdef CONFIG_LOCK_STAT | |
63 | int lock_stat = 1; | |
64 | module_param(lock_stat, int, 0644); | |
65 | #else | |
66 | #define lock_stat 0 | |
67 | #endif | |
68 | ||
fbb9ce95 | 69 | /* |
74c383f1 IM |
70 | * lockdep_lock: protects the lockdep graph, the hashes and the |
71 | * class/list/hash allocators. | |
fbb9ce95 IM |
72 | * |
73 | * This is one of the rare exceptions where it's justified | |
74 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 75 | * code to recurse back into the lockdep code... |
fbb9ce95 | 76 | */ |
edc35bd7 | 77 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
78 | |
79 | static int graph_lock(void) | |
80 | { | |
0199c4e6 | 81 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
82 | /* |
83 | * Make sure that if another CPU detected a bug while | |
84 | * walking the graph we dont change it (while the other | |
85 | * CPU is busy printing out stuff with the graph lock | |
86 | * dropped already) | |
87 | */ | |
88 | if (!debug_locks) { | |
0199c4e6 | 89 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
90 | return 0; |
91 | } | |
bb065afb SR |
92 | /* prevent any recursions within lockdep from causing deadlocks */ |
93 | current->lockdep_recursion++; | |
74c383f1 IM |
94 | return 1; |
95 | } | |
96 | ||
97 | static inline int graph_unlock(void) | |
98 | { | |
0199c4e6 | 99 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) |
381a2292 JP |
100 | return DEBUG_LOCKS_WARN_ON(1); |
101 | ||
bb065afb | 102 | current->lockdep_recursion--; |
0199c4e6 | 103 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
104 | return 0; |
105 | } | |
106 | ||
107 | /* | |
108 | * Turn lock debugging off and return with 0 if it was off already, | |
109 | * and also release the graph lock: | |
110 | */ | |
111 | static inline int debug_locks_off_graph_unlock(void) | |
112 | { | |
113 | int ret = debug_locks_off(); | |
114 | ||
0199c4e6 | 115 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
116 | |
117 | return ret; | |
118 | } | |
fbb9ce95 IM |
119 | |
120 | static int lockdep_initialized; | |
121 | ||
122 | unsigned long nr_list_entries; | |
af012961 | 123 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 124 | |
fbb9ce95 IM |
125 | /* |
126 | * All data structures here are protected by the global debug_lock. | |
127 | * | |
128 | * Mutex key structs only get allocated, once during bootup, and never | |
129 | * get freed - this significantly simplifies the debugging code. | |
130 | */ | |
131 | unsigned long nr_lock_classes; | |
132 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
133 | ||
f82b217e DJ |
134 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
135 | { | |
136 | if (!hlock->class_idx) { | |
137 | DEBUG_LOCKS_WARN_ON(1); | |
138 | return NULL; | |
139 | } | |
140 | return lock_classes + hlock->class_idx - 1; | |
141 | } | |
142 | ||
f20786ff | 143 | #ifdef CONFIG_LOCK_STAT |
1871e52c TH |
144 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
145 | cpu_lock_stats); | |
f20786ff | 146 | |
3365e779 PZ |
147 | static inline u64 lockstat_clock(void) |
148 | { | |
149 | return cpu_clock(smp_processor_id()); | |
150 | } | |
151 | ||
c7e78cff | 152 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
153 | { |
154 | int i; | |
155 | ||
c7e78cff PZ |
156 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
157 | if (points[i] == 0) { | |
158 | points[i] = ip; | |
f20786ff PZ |
159 | break; |
160 | } | |
c7e78cff | 161 | if (points[i] == ip) |
f20786ff PZ |
162 | break; |
163 | } | |
164 | ||
165 | return i; | |
166 | } | |
167 | ||
3365e779 | 168 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
169 | { |
170 | if (time > lt->max) | |
171 | lt->max = time; | |
172 | ||
109d71c6 | 173 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
174 | lt->min = time; |
175 | ||
176 | lt->total += time; | |
177 | lt->nr++; | |
178 | } | |
179 | ||
c46261de PZ |
180 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
181 | { | |
109d71c6 FR |
182 | if (!src->nr) |
183 | return; | |
184 | ||
185 | if (src->max > dst->max) | |
186 | dst->max = src->max; | |
187 | ||
188 | if (src->min < dst->min || !dst->nr) | |
189 | dst->min = src->min; | |
190 | ||
c46261de PZ |
191 | dst->total += src->total; |
192 | dst->nr += src->nr; | |
193 | } | |
194 | ||
195 | struct lock_class_stats lock_stats(struct lock_class *class) | |
196 | { | |
197 | struct lock_class_stats stats; | |
198 | int cpu, i; | |
199 | ||
200 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
201 | for_each_possible_cpu(cpu) { | |
202 | struct lock_class_stats *pcs = | |
1871e52c | 203 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
204 | |
205 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
206 | stats.contention_point[i] += pcs->contention_point[i]; | |
207 | ||
c7e78cff PZ |
208 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
209 | stats.contending_point[i] += pcs->contending_point[i]; | |
210 | ||
c46261de PZ |
211 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
212 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
213 | ||
214 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
215 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
216 | |
217 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
218 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
219 | } |
220 | ||
221 | return stats; | |
222 | } | |
223 | ||
224 | void clear_lock_stats(struct lock_class *class) | |
225 | { | |
226 | int cpu; | |
227 | ||
228 | for_each_possible_cpu(cpu) { | |
229 | struct lock_class_stats *cpu_stats = | |
1871e52c | 230 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
231 | |
232 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
233 | } | |
234 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 235 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
236 | } |
237 | ||
f20786ff PZ |
238 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
239 | { | |
1871e52c | 240 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
241 | } |
242 | ||
243 | static void put_lock_stats(struct lock_class_stats *stats) | |
244 | { | |
1871e52c | 245 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
246 | } |
247 | ||
248 | static void lock_release_holdtime(struct held_lock *hlock) | |
249 | { | |
250 | struct lock_class_stats *stats; | |
3365e779 | 251 | u64 holdtime; |
f20786ff PZ |
252 | |
253 | if (!lock_stat) | |
254 | return; | |
255 | ||
3365e779 | 256 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 257 | |
f82b217e | 258 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
259 | if (hlock->read) |
260 | lock_time_inc(&stats->read_holdtime, holdtime); | |
261 | else | |
262 | lock_time_inc(&stats->write_holdtime, holdtime); | |
263 | put_lock_stats(stats); | |
264 | } | |
265 | #else | |
266 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
267 | { | |
268 | } | |
269 | #endif | |
270 | ||
fbb9ce95 IM |
271 | /* |
272 | * We keep a global list of all lock classes. The list only grows, | |
273 | * never shrinks. The list is only accessed with the lockdep | |
274 | * spinlock lock held. | |
275 | */ | |
276 | LIST_HEAD(all_lock_classes); | |
277 | ||
278 | /* | |
279 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
280 | */ | |
281 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
282 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 283 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
284 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
285 | ||
286 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
287 | ||
fbb9ce95 IM |
288 | /* |
289 | * We put the lock dependency chains into a hash-table as well, to cache | |
290 | * their existence: | |
291 | */ | |
292 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
293 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 294 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
295 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
296 | ||
297 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
298 | ||
299 | /* | |
300 | * The hash key of the lock dependency chains is a hash itself too: | |
301 | * it's a hash of all locks taken up to that lock, including that lock. | |
302 | * It's a 64-bit hash, because it's important for the keys to be | |
303 | * unique. | |
304 | */ | |
305 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
306 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
307 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
308 | (key2)) |
309 | ||
1d09daa5 | 310 | void lockdep_off(void) |
fbb9ce95 IM |
311 | { |
312 | current->lockdep_recursion++; | |
313 | } | |
fbb9ce95 IM |
314 | EXPORT_SYMBOL(lockdep_off); |
315 | ||
1d09daa5 | 316 | void lockdep_on(void) |
fbb9ce95 IM |
317 | { |
318 | current->lockdep_recursion--; | |
319 | } | |
fbb9ce95 IM |
320 | EXPORT_SYMBOL(lockdep_on); |
321 | ||
fbb9ce95 IM |
322 | /* |
323 | * Debugging switches: | |
324 | */ | |
325 | ||
326 | #define VERBOSE 0 | |
33e94e96 | 327 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
328 | |
329 | #if VERBOSE | |
330 | # define HARDIRQ_VERBOSE 1 | |
331 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 332 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
333 | #else |
334 | # define HARDIRQ_VERBOSE 0 | |
335 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 336 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
337 | #endif |
338 | ||
cf40bd16 | 339 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
340 | /* |
341 | * Quick filtering for interesting events: | |
342 | */ | |
343 | static int class_filter(struct lock_class *class) | |
344 | { | |
f9829cce AK |
345 | #if 0 |
346 | /* Example */ | |
fbb9ce95 | 347 | if (class->name_version == 1 && |
f9829cce | 348 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
349 | return 1; |
350 | if (class->name_version == 1 && | |
f9829cce | 351 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 352 | return 1; |
f9829cce | 353 | #endif |
a6640897 IM |
354 | /* Filter everything else. 1 would be to allow everything else */ |
355 | return 0; | |
fbb9ce95 IM |
356 | } |
357 | #endif | |
358 | ||
359 | static int verbose(struct lock_class *class) | |
360 | { | |
361 | #if VERBOSE | |
362 | return class_filter(class); | |
363 | #endif | |
364 | return 0; | |
365 | } | |
366 | ||
fbb9ce95 IM |
367 | /* |
368 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 369 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
370 | */ |
371 | unsigned long nr_stack_trace_entries; | |
372 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
373 | ||
374 | static int save_trace(struct stack_trace *trace) | |
375 | { | |
376 | trace->nr_entries = 0; | |
377 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
378 | trace->entries = stack_trace + nr_stack_trace_entries; | |
379 | ||
5a1b3999 | 380 | trace->skip = 3; |
5a1b3999 | 381 | |
ab1b6f03 | 382 | save_stack_trace(trace); |
fbb9ce95 | 383 | |
4f84f433 PZ |
384 | /* |
385 | * Some daft arches put -1 at the end to indicate its a full trace. | |
386 | * | |
387 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
388 | * complete trace that maxes out the entries provided will be reported | |
389 | * as incomplete, friggin useless </rant> | |
390 | */ | |
ea5b41f9 TL |
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 | ||
493 | static void print_lock_name(struct lock_class *class) | |
494 | { | |
f510b233 | 495 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
496 | const char *name; |
497 | ||
f510b233 | 498 | get_usage_chars(class, usage); |
fbb9ce95 IM |
499 | |
500 | name = class->name; | |
501 | if (!name) { | |
502 | name = __get_key_name(class->key, str); | |
503 | printk(" (%s", name); | |
504 | } else { | |
505 | printk(" (%s", name); | |
506 | if (class->name_version > 1) | |
507 | printk("#%d", class->name_version); | |
508 | if (class->subclass) | |
509 | printk("/%d", class->subclass); | |
510 | } | |
f510b233 | 511 | printk("){%s}", usage); |
fbb9ce95 IM |
512 | } |
513 | ||
514 | static void print_lockdep_cache(struct lockdep_map *lock) | |
515 | { | |
516 | const char *name; | |
9281acea | 517 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
518 | |
519 | name = lock->name; | |
520 | if (!name) | |
521 | name = __get_key_name(lock->key->subkeys, str); | |
522 | ||
523 | printk("%s", name); | |
524 | } | |
525 | ||
526 | static void print_lock(struct held_lock *hlock) | |
527 | { | |
f82b217e | 528 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
529 | printk(", at: "); |
530 | print_ip_sym(hlock->acquire_ip); | |
531 | } | |
532 | ||
533 | static void lockdep_print_held_locks(struct task_struct *curr) | |
534 | { | |
535 | int i, depth = curr->lockdep_depth; | |
536 | ||
537 | if (!depth) { | |
ba25f9dc | 538 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
539 | return; |
540 | } | |
541 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 542 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
543 | |
544 | for (i = 0; i < depth; i++) { | |
545 | printk(" #%d: ", i); | |
546 | print_lock(curr->held_locks + i); | |
547 | } | |
548 | } | |
fbb9ce95 | 549 | |
8e18257d PZ |
550 | static void print_kernel_version(void) |
551 | { | |
552 | printk("%s %.*s\n", init_utsname()->release, | |
553 | (int)strcspn(init_utsname()->version, " "), | |
554 | init_utsname()->version); | |
555 | } | |
556 | ||
557 | static int very_verbose(struct lock_class *class) | |
558 | { | |
559 | #if VERY_VERBOSE | |
560 | return class_filter(class); | |
561 | #endif | |
562 | return 0; | |
563 | } | |
564 | ||
fbb9ce95 | 565 | /* |
8e18257d | 566 | * Is this the address of a static object: |
fbb9ce95 | 567 | */ |
8e18257d | 568 | static int static_obj(void *obj) |
fbb9ce95 | 569 | { |
8e18257d PZ |
570 | unsigned long start = (unsigned long) &_stext, |
571 | end = (unsigned long) &_end, | |
572 | addr = (unsigned long) obj; | |
8e18257d | 573 | |
fbb9ce95 | 574 | /* |
8e18257d | 575 | * static variable? |
fbb9ce95 | 576 | */ |
8e18257d PZ |
577 | if ((addr >= start) && (addr < end)) |
578 | return 1; | |
fbb9ce95 | 579 | |
2a9ad18d MF |
580 | if (arch_is_kernel_data(addr)) |
581 | return 1; | |
582 | ||
fbb9ce95 | 583 | /* |
10fad5e4 | 584 | * in-kernel percpu var? |
fbb9ce95 | 585 | */ |
10fad5e4 TH |
586 | if (is_kernel_percpu_address(addr)) |
587 | return 1; | |
fbb9ce95 | 588 | |
8e18257d | 589 | /* |
10fad5e4 | 590 | * module static or percpu var? |
8e18257d | 591 | */ |
10fad5e4 | 592 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a DJ |
593 | } |
594 | ||
fbb9ce95 | 595 | /* |
8e18257d PZ |
596 | * To make lock name printouts unique, we calculate a unique |
597 | * class->name_version generation counter: | |
fbb9ce95 | 598 | */ |
8e18257d | 599 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 600 | { |
8e18257d PZ |
601 | struct lock_class *class; |
602 | int count = 0; | |
fbb9ce95 | 603 | |
8e18257d | 604 | if (!new_class->name) |
fbb9ce95 IM |
605 | return 0; |
606 | ||
8e18257d PZ |
607 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
608 | if (new_class->key - new_class->subclass == class->key) | |
609 | return class->name_version; | |
610 | if (class->name && !strcmp(class->name, new_class->name)) | |
611 | count = max(count, class->name_version); | |
612 | } | |
fbb9ce95 | 613 | |
8e18257d | 614 | return count + 1; |
fbb9ce95 IM |
615 | } |
616 | ||
8e18257d PZ |
617 | /* |
618 | * Register a lock's class in the hash-table, if the class is not present | |
619 | * yet. Otherwise we look it up. We cache the result in the lock object | |
620 | * itself, so actual lookup of the hash should be once per lock object. | |
621 | */ | |
622 | static inline struct lock_class * | |
623 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 624 | { |
8e18257d PZ |
625 | struct lockdep_subclass_key *key; |
626 | struct list_head *hash_head; | |
627 | struct lock_class *class; | |
fbb9ce95 | 628 | |
8e18257d PZ |
629 | #ifdef CONFIG_DEBUG_LOCKDEP |
630 | /* | |
631 | * If the architecture calls into lockdep before initializing | |
632 | * the hashes then we'll warn about it later. (we cannot printk | |
633 | * right now) | |
634 | */ | |
635 | if (unlikely(!lockdep_initialized)) { | |
636 | lockdep_init(); | |
637 | lockdep_init_error = 1; | |
c71063c9 | 638 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
639 | } |
640 | #endif | |
fbb9ce95 | 641 | |
8e18257d PZ |
642 | /* |
643 | * Static locks do not have their class-keys yet - for them the key | |
644 | * is the lock object itself: | |
645 | */ | |
646 | if (unlikely(!lock->key)) | |
647 | lock->key = (void *)lock; | |
fbb9ce95 | 648 | |
8e18257d PZ |
649 | /* |
650 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
651 | * lock_class_key variable is passed in through the mutex_init() | |
652 | * (or spin_lock_init()) call - which acts as the key. For static | |
653 | * locks we use the lock object itself as the key. | |
654 | */ | |
4b32d0a4 PZ |
655 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
656 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 657 | |
8e18257d | 658 | key = lock->key->subkeys + subclass; |
ca268c69 | 659 | |
8e18257d | 660 | hash_head = classhashentry(key); |
74c383f1 | 661 | |
8e18257d PZ |
662 | /* |
663 | * We can walk the hash lockfree, because the hash only | |
664 | * grows, and we are careful when adding entries to the end: | |
665 | */ | |
4b32d0a4 PZ |
666 | list_for_each_entry(class, hash_head, hash_entry) { |
667 | if (class->key == key) { | |
668 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 669 | return class; |
4b32d0a4 PZ |
670 | } |
671 | } | |
fbb9ce95 | 672 | |
8e18257d | 673 | return NULL; |
fbb9ce95 IM |
674 | } |
675 | ||
676 | /* | |
8e18257d PZ |
677 | * Register a lock's class in the hash-table, if the class is not present |
678 | * yet. Otherwise we look it up. We cache the result in the lock object | |
679 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 680 | */ |
8e18257d PZ |
681 | static inline struct lock_class * |
682 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 683 | { |
8e18257d PZ |
684 | struct lockdep_subclass_key *key; |
685 | struct list_head *hash_head; | |
686 | struct lock_class *class; | |
687 | unsigned long flags; | |
688 | ||
689 | class = look_up_lock_class(lock, subclass); | |
690 | if (likely(class)) | |
691 | return class; | |
692 | ||
693 | /* | |
694 | * Debug-check: all keys must be persistent! | |
695 | */ | |
696 | if (!static_obj(lock->key)) { | |
697 | debug_locks_off(); | |
698 | printk("INFO: trying to register non-static key.\n"); | |
699 | printk("the code is fine but needs lockdep annotation.\n"); | |
700 | printk("turning off the locking correctness validator.\n"); | |
701 | dump_stack(); | |
702 | ||
703 | return NULL; | |
704 | } | |
705 | ||
706 | key = lock->key->subkeys + subclass; | |
707 | hash_head = classhashentry(key); | |
708 | ||
709 | raw_local_irq_save(flags); | |
710 | if (!graph_lock()) { | |
711 | raw_local_irq_restore(flags); | |
712 | return NULL; | |
713 | } | |
714 | /* | |
715 | * We have to do the hash-walk again, to avoid races | |
716 | * with another CPU: | |
717 | */ | |
718 | list_for_each_entry(class, hash_head, hash_entry) | |
719 | if (class->key == key) | |
720 | goto out_unlock_set; | |
721 | /* | |
722 | * Allocate a new key from the static array, and add it to | |
723 | * the hash: | |
724 | */ | |
725 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
726 | if (!debug_locks_off_graph_unlock()) { | |
727 | raw_local_irq_restore(flags); | |
728 | return NULL; | |
729 | } | |
730 | raw_local_irq_restore(flags); | |
731 | ||
732 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
733 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 734 | dump_stack(); |
8e18257d PZ |
735 | return NULL; |
736 | } | |
737 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 738 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
739 | class->key = key; |
740 | class->name = lock->name; | |
741 | class->subclass = subclass; | |
742 | INIT_LIST_HEAD(&class->lock_entry); | |
743 | INIT_LIST_HEAD(&class->locks_before); | |
744 | INIT_LIST_HEAD(&class->locks_after); | |
745 | class->name_version = count_matching_names(class); | |
746 | /* | |
747 | * We use RCU's safe list-add method to make | |
748 | * parallel walking of the hash-list safe: | |
749 | */ | |
750 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
751 | /* |
752 | * Add it to the global list of classes: | |
753 | */ | |
754 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
755 | |
756 | if (verbose(class)) { | |
757 | graph_unlock(); | |
758 | raw_local_irq_restore(flags); | |
759 | ||
760 | printk("\nnew class %p: %s", class->key, class->name); | |
761 | if (class->name_version > 1) | |
762 | printk("#%d", class->name_version); | |
763 | printk("\n"); | |
764 | dump_stack(); | |
765 | ||
766 | raw_local_irq_save(flags); | |
767 | if (!graph_lock()) { | |
768 | raw_local_irq_restore(flags); | |
769 | return NULL; | |
770 | } | |
771 | } | |
772 | out_unlock_set: | |
773 | graph_unlock(); | |
774 | raw_local_irq_restore(flags); | |
775 | ||
776 | if (!subclass || force) | |
777 | lock->class_cache = class; | |
778 | ||
779 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
780 | return NULL; | |
781 | ||
782 | return class; | |
783 | } | |
784 | ||
785 | #ifdef CONFIG_PROVE_LOCKING | |
786 | /* | |
787 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
788 | * with NULL on failure) | |
789 | */ | |
790 | static struct lock_list *alloc_list_entry(void) | |
791 | { | |
792 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
793 | if (!debug_locks_off_graph_unlock()) | |
794 | return NULL; | |
795 | ||
796 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
797 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 798 | dump_stack(); |
8e18257d PZ |
799 | return NULL; |
800 | } | |
801 | return list_entries + nr_list_entries++; | |
802 | } | |
803 | ||
804 | /* | |
805 | * Add a new dependency to the head of the list: | |
806 | */ | |
807 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
808 | struct list_head *head, unsigned long ip, int distance) | |
809 | { | |
810 | struct lock_list *entry; | |
811 | /* | |
812 | * Lock not present yet - get a new dependency struct and | |
813 | * add it to the list: | |
814 | */ | |
815 | entry = alloc_list_entry(); | |
816 | if (!entry) | |
817 | return 0; | |
818 | ||
8e18257d PZ |
819 | if (!save_trace(&entry->trace)) |
820 | return 0; | |
821 | ||
74870172 ZY |
822 | entry->class = this; |
823 | entry->distance = distance; | |
8e18257d PZ |
824 | /* |
825 | * Since we never remove from the dependency list, the list can | |
826 | * be walked lockless by other CPUs, it's only allocation | |
827 | * that must be protected by the spinlock. But this also means | |
828 | * we must make new entries visible only once writes to the | |
829 | * entry become visible - hence the RCU op: | |
830 | */ | |
831 | list_add_tail_rcu(&entry->entry, head); | |
832 | ||
833 | return 1; | |
834 | } | |
835 | ||
98c33edd PZ |
836 | /* |
837 | * For good efficiency of modular, we use power of 2 | |
838 | */ | |
af012961 PZ |
839 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
840 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
841 | ||
98c33edd PZ |
842 | /* |
843 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
844 | * breadth-first search(BFS)algorithem, by which we can build |
845 | * the shortest path from the next lock to be acquired to the | |
846 | * previous held lock if there is a circular between them. | |
98c33edd | 847 | */ |
af012961 PZ |
848 | struct circular_queue { |
849 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
850 | unsigned int front, rear; | |
851 | }; | |
852 | ||
853 | static struct circular_queue lock_cq; | |
af012961 | 854 | |
12f3dfd0 | 855 | unsigned int max_bfs_queue_depth; |
af012961 | 856 | |
e351b660 ML |
857 | static unsigned int lockdep_dependency_gen_id; |
858 | ||
af012961 PZ |
859 | static inline void __cq_init(struct circular_queue *cq) |
860 | { | |
861 | cq->front = cq->rear = 0; | |
e351b660 | 862 | lockdep_dependency_gen_id++; |
af012961 PZ |
863 | } |
864 | ||
865 | static inline int __cq_empty(struct circular_queue *cq) | |
866 | { | |
867 | return (cq->front == cq->rear); | |
868 | } | |
869 | ||
870 | static inline int __cq_full(struct circular_queue *cq) | |
871 | { | |
872 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
873 | } | |
874 | ||
875 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
876 | { | |
877 | if (__cq_full(cq)) | |
878 | return -1; | |
879 | ||
880 | cq->element[cq->rear] = elem; | |
881 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
882 | return 0; | |
883 | } | |
884 | ||
885 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
886 | { | |
887 | if (__cq_empty(cq)) | |
888 | return -1; | |
889 | ||
890 | *elem = cq->element[cq->front]; | |
891 | cq->front = (cq->front + 1) & CQ_MASK; | |
892 | return 0; | |
893 | } | |
894 | ||
895 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
896 | { | |
897 | return (cq->rear - cq->front) & CQ_MASK; | |
898 | } | |
899 | ||
900 | static inline void mark_lock_accessed(struct lock_list *lock, | |
901 | struct lock_list *parent) | |
902 | { | |
903 | unsigned long nr; | |
98c33edd | 904 | |
af012961 PZ |
905 | nr = lock - list_entries; |
906 | WARN_ON(nr >= nr_list_entries); | |
907 | lock->parent = parent; | |
e351b660 | 908 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
909 | } |
910 | ||
911 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
912 | { | |
913 | unsigned long nr; | |
98c33edd | 914 | |
af012961 PZ |
915 | nr = lock - list_entries; |
916 | WARN_ON(nr >= nr_list_entries); | |
e351b660 | 917 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
918 | } |
919 | ||
920 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
921 | { | |
922 | return child->parent; | |
923 | } | |
924 | ||
925 | static inline int get_lock_depth(struct lock_list *child) | |
926 | { | |
927 | int depth = 0; | |
928 | struct lock_list *parent; | |
929 | ||
930 | while ((parent = get_lock_parent(child))) { | |
931 | child = parent; | |
932 | depth++; | |
933 | } | |
934 | return depth; | |
935 | } | |
936 | ||
9e2d551e | 937 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
938 | void *data, |
939 | int (*match)(struct lock_list *entry, void *data), | |
940 | struct lock_list **target_entry, | |
941 | int forward) | |
c94aa5ca ML |
942 | { |
943 | struct lock_list *entry; | |
d588e461 | 944 | struct list_head *head; |
c94aa5ca ML |
945 | struct circular_queue *cq = &lock_cq; |
946 | int ret = 1; | |
947 | ||
9e2d551e | 948 | if (match(source_entry, data)) { |
c94aa5ca ML |
949 | *target_entry = source_entry; |
950 | ret = 0; | |
951 | goto exit; | |
952 | } | |
953 | ||
d588e461 ML |
954 | if (forward) |
955 | head = &source_entry->class->locks_after; | |
956 | else | |
957 | head = &source_entry->class->locks_before; | |
958 | ||
959 | if (list_empty(head)) | |
960 | goto exit; | |
961 | ||
962 | __cq_init(cq); | |
c94aa5ca ML |
963 | __cq_enqueue(cq, (unsigned long)source_entry); |
964 | ||
965 | while (!__cq_empty(cq)) { | |
966 | struct lock_list *lock; | |
c94aa5ca ML |
967 | |
968 | __cq_dequeue(cq, (unsigned long *)&lock); | |
969 | ||
970 | if (!lock->class) { | |
971 | ret = -2; | |
972 | goto exit; | |
973 | } | |
974 | ||
975 | if (forward) | |
976 | head = &lock->class->locks_after; | |
977 | else | |
978 | head = &lock->class->locks_before; | |
979 | ||
980 | list_for_each_entry(entry, head, entry) { | |
981 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 982 | unsigned int cq_depth; |
c94aa5ca | 983 | mark_lock_accessed(entry, lock); |
9e2d551e | 984 | if (match(entry, data)) { |
c94aa5ca ML |
985 | *target_entry = entry; |
986 | ret = 0; | |
987 | goto exit; | |
988 | } | |
989 | ||
990 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
991 | ret = -1; | |
992 | goto exit; | |
993 | } | |
12f3dfd0 ML |
994 | cq_depth = __cq_get_elem_count(cq); |
995 | if (max_bfs_queue_depth < cq_depth) | |
996 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
997 | } |
998 | } | |
999 | } | |
1000 | exit: | |
1001 | return ret; | |
1002 | } | |
1003 | ||
d7aaba14 | 1004 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1005 | void *data, |
1006 | int (*match)(struct lock_list *entry, void *data), | |
1007 | struct lock_list **target_entry) | |
c94aa5ca | 1008 | { |
9e2d551e | 1009 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1010 | |
1011 | } | |
1012 | ||
d7aaba14 | 1013 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1014 | void *data, |
1015 | int (*match)(struct lock_list *entry, void *data), | |
1016 | struct lock_list **target_entry) | |
c94aa5ca | 1017 | { |
9e2d551e | 1018 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1019 | |
1020 | } | |
1021 | ||
8e18257d PZ |
1022 | /* |
1023 | * Recursive, forwards-direction lock-dependency checking, used for | |
1024 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1025 | * checking. | |
8e18257d | 1026 | */ |
8e18257d PZ |
1027 | |
1028 | /* | |
1029 | * Print a dependency chain entry (this is only done when a deadlock | |
1030 | * has been detected): | |
1031 | */ | |
1032 | static noinline int | |
24208ca7 | 1033 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1034 | { |
1035 | if (debug_locks_silent) | |
1036 | return 0; | |
1037 | printk("\n-> #%u", depth); | |
1038 | print_lock_name(target->class); | |
1039 | printk(":\n"); | |
1040 | print_stack_trace(&target->trace, 6); | |
1041 | ||
1042 | return 0; | |
1043 | } | |
1044 | ||
1045 | /* | |
1046 | * When a circular dependency is detected, print the | |
1047 | * header first: | |
1048 | */ | |
1049 | static noinline int | |
db0002a3 ML |
1050 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1051 | struct held_lock *check_src, | |
1052 | struct held_lock *check_tgt) | |
8e18257d PZ |
1053 | { |
1054 | struct task_struct *curr = current; | |
1055 | ||
c94aa5ca | 1056 | if (debug_locks_silent) |
8e18257d PZ |
1057 | return 0; |
1058 | ||
1059 | printk("\n=======================================================\n"); | |
1060 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1061 | print_kernel_version(); | |
1062 | printk( "-------------------------------------------------------\n"); | |
1063 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1064 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1065 | print_lock(check_src); |
8e18257d | 1066 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1067 | print_lock(check_tgt); |
8e18257d PZ |
1068 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1069 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1070 | ||
1071 | print_circular_bug_entry(entry, depth); | |
1072 | ||
1073 | return 0; | |
1074 | } | |
1075 | ||
9e2d551e ML |
1076 | static inline int class_equal(struct lock_list *entry, void *data) |
1077 | { | |
1078 | return entry->class == data; | |
1079 | } | |
1080 | ||
db0002a3 ML |
1081 | static noinline int print_circular_bug(struct lock_list *this, |
1082 | struct lock_list *target, | |
1083 | struct held_lock *check_src, | |
1084 | struct held_lock *check_tgt) | |
8e18257d PZ |
1085 | { |
1086 | struct task_struct *curr = current; | |
c94aa5ca | 1087 | struct lock_list *parent; |
24208ca7 | 1088 | int depth; |
8e18257d | 1089 | |
c94aa5ca | 1090 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1091 | return 0; |
1092 | ||
db0002a3 | 1093 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1094 | return 0; |
1095 | ||
c94aa5ca ML |
1096 | depth = get_lock_depth(target); |
1097 | ||
db0002a3 | 1098 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1099 | |
1100 | parent = get_lock_parent(target); | |
1101 | ||
1102 | while (parent) { | |
1103 | print_circular_bug_entry(parent, --depth); | |
1104 | parent = get_lock_parent(parent); | |
1105 | } | |
8e18257d PZ |
1106 | |
1107 | printk("\nother info that might help us debug this:\n\n"); | |
1108 | lockdep_print_held_locks(curr); | |
1109 | ||
1110 | printk("\nstack backtrace:\n"); | |
1111 | dump_stack(); | |
1112 | ||
1113 | return 0; | |
1114 | } | |
1115 | ||
db0002a3 ML |
1116 | static noinline int print_bfs_bug(int ret) |
1117 | { | |
1118 | if (!debug_locks_off_graph_unlock()) | |
1119 | return 0; | |
1120 | ||
1121 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1122 | ||
1123 | return 0; | |
1124 | } | |
1125 | ||
ef681026 | 1126 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1127 | { |
ef681026 ML |
1128 | (*(unsigned long *)data)++; |
1129 | return 0; | |
1130 | } | |
419ca3f1 | 1131 | |
ef681026 ML |
1132 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1133 | { | |
1134 | unsigned long count = 0; | |
1135 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1136 | |
ef681026 | 1137 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1138 | |
ef681026 | 1139 | return count; |
419ca3f1 | 1140 | } |
419ca3f1 DM |
1141 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1142 | { | |
1143 | unsigned long ret, flags; | |
ef681026 ML |
1144 | struct lock_list this; |
1145 | ||
1146 | this.parent = NULL; | |
1147 | this.class = class; | |
419ca3f1 DM |
1148 | |
1149 | local_irq_save(flags); | |
0199c4e6 | 1150 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1151 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1152 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1153 | local_irq_restore(flags); |
1154 | ||
1155 | return ret; | |
1156 | } | |
1157 | ||
ef681026 | 1158 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1159 | { |
ef681026 ML |
1160 | unsigned long count = 0; |
1161 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1162 | |
ef681026 | 1163 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1164 | |
ef681026 | 1165 | return count; |
419ca3f1 DM |
1166 | } |
1167 | ||
1168 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1169 | { | |
1170 | unsigned long ret, flags; | |
ef681026 ML |
1171 | struct lock_list this; |
1172 | ||
1173 | this.parent = NULL; | |
1174 | this.class = class; | |
419ca3f1 DM |
1175 | |
1176 | local_irq_save(flags); | |
0199c4e6 | 1177 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1178 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1179 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1180 | local_irq_restore(flags); |
1181 | ||
1182 | return ret; | |
1183 | } | |
1184 | ||
8e18257d PZ |
1185 | /* |
1186 | * Prove that the dependency graph starting at <entry> can not | |
1187 | * lead to <target>. Print an error and return 0 if it does. | |
1188 | */ | |
1189 | static noinline int | |
db0002a3 ML |
1190 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1191 | struct lock_list **target_entry) | |
8e18257d | 1192 | { |
db0002a3 | 1193 | int result; |
8e18257d | 1194 | |
bd6d29c2 | 1195 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1196 | |
d7aaba14 | 1197 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1198 | |
db0002a3 ML |
1199 | return result; |
1200 | } | |
c94aa5ca | 1201 | |
81d68a96 | 1202 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1203 | /* |
1204 | * Forwards and backwards subgraph searching, for the purposes of | |
1205 | * proving that two subgraphs can be connected by a new dependency | |
1206 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1207 | */ | |
fbb9ce95 | 1208 | |
d7aaba14 ML |
1209 | static inline int usage_match(struct lock_list *entry, void *bit) |
1210 | { | |
1211 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1212 | } | |
1213 | ||
1214 | ||
1215 | ||
fbb9ce95 IM |
1216 | /* |
1217 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1218 | * at @root->class that matches @bit. |
fbb9ce95 | 1219 | * |
d7aaba14 ML |
1220 | * Return 0 if such a node exists in the subgraph, and put that node |
1221 | * into *@target_entry. | |
fbb9ce95 | 1222 | * |
d7aaba14 ML |
1223 | * Return 1 otherwise and keep *@target_entry unchanged. |
1224 | * Return <0 on error. | |
fbb9ce95 | 1225 | */ |
d7aaba14 ML |
1226 | static int |
1227 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1228 | struct lock_list **target_entry) | |
fbb9ce95 | 1229 | { |
d7aaba14 | 1230 | int result; |
fbb9ce95 | 1231 | |
bd6d29c2 | 1232 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1233 | |
d7aaba14 ML |
1234 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1235 | ||
1236 | return result; | |
fbb9ce95 IM |
1237 | } |
1238 | ||
1239 | /* | |
1240 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1241 | * at @root->class that matches @bit. |
fbb9ce95 | 1242 | * |
d7aaba14 ML |
1243 | * Return 0 if such a node exists in the subgraph, and put that node |
1244 | * into *@target_entry. | |
fbb9ce95 | 1245 | * |
d7aaba14 ML |
1246 | * Return 1 otherwise and keep *@target_entry unchanged. |
1247 | * Return <0 on error. | |
fbb9ce95 | 1248 | */ |
d7aaba14 ML |
1249 | static int |
1250 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1251 | struct lock_list **target_entry) | |
fbb9ce95 | 1252 | { |
d7aaba14 | 1253 | int result; |
fbb9ce95 | 1254 | |
bd6d29c2 | 1255 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1256 | |
d7aaba14 | 1257 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1258 | |
d7aaba14 | 1259 | return result; |
fbb9ce95 IM |
1260 | } |
1261 | ||
af012961 PZ |
1262 | static void print_lock_class_header(struct lock_class *class, int depth) |
1263 | { | |
1264 | int bit; | |
1265 | ||
1266 | printk("%*s->", depth, ""); | |
1267 | print_lock_name(class); | |
1268 | printk(" ops: %lu", class->ops); | |
1269 | printk(" {\n"); | |
1270 | ||
1271 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1272 | if (class->usage_mask & (1 << bit)) { | |
1273 | int len = depth; | |
1274 | ||
1275 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1276 | len += printk(" at:\n"); | |
1277 | print_stack_trace(class->usage_traces + bit, len); | |
1278 | } | |
1279 | } | |
1280 | printk("%*s }\n", depth, ""); | |
1281 | ||
1282 | printk("%*s ... key at: ",depth,""); | |
1283 | print_ip_sym((unsigned long)class->key); | |
1284 | } | |
1285 | ||
1286 | /* | |
1287 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1288 | */ | |
1289 | static void __used | |
1290 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1291 | struct lock_list *root) | |
1292 | { | |
1293 | struct lock_list *entry = leaf; | |
1294 | int depth; | |
1295 | ||
1296 | /*compute depth from generated tree by BFS*/ | |
1297 | depth = get_lock_depth(leaf); | |
1298 | ||
1299 | do { | |
1300 | print_lock_class_header(entry->class, depth); | |
1301 | printk("%*s ... acquired at:\n", depth, ""); | |
1302 | print_stack_trace(&entry->trace, 2); | |
1303 | printk("\n"); | |
1304 | ||
1305 | if (depth == 0 && (entry != root)) { | |
1306 | printk("lockdep:%s bad BFS generated tree\n", __func__); | |
1307 | break; | |
1308 | } | |
1309 | ||
1310 | entry = get_lock_parent(entry); | |
1311 | depth--; | |
1312 | } while (entry && (depth >= 0)); | |
1313 | ||
1314 | return; | |
1315 | } | |
d7aaba14 | 1316 | |
fbb9ce95 IM |
1317 | static int |
1318 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1319 | struct lock_list *prev_root, |
1320 | struct lock_list *next_root, | |
1321 | struct lock_list *backwards_entry, | |
1322 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1323 | struct held_lock *prev, |
1324 | struct held_lock *next, | |
1325 | enum lock_usage_bit bit1, | |
1326 | enum lock_usage_bit bit2, | |
1327 | const char *irqclass) | |
1328 | { | |
74c383f1 | 1329 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1330 | return 0; |
1331 | ||
1332 | printk("\n======================================================\n"); | |
1333 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1334 | irqclass, irqclass); | |
99de055a | 1335 | print_kernel_version(); |
fbb9ce95 IM |
1336 | printk( "------------------------------------------------------\n"); |
1337 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1338 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1339 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1340 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1341 | curr->hardirqs_enabled, | |
1342 | curr->softirqs_enabled); | |
1343 | print_lock(next); | |
1344 | ||
1345 | printk("\nand this task is already holding:\n"); | |
1346 | print_lock(prev); | |
1347 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1348 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1349 | printk(" ->"); |
f82b217e | 1350 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1351 | printk("\n"); |
1352 | ||
1353 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1354 | irqclass); | |
24208ca7 | 1355 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1356 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1357 | ||
24208ca7 | 1358 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1359 | |
1360 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1361 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1362 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1363 | printk("..."); | |
1364 | ||
24208ca7 | 1365 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1366 | |
1367 | printk("\nother info that might help us debug this:\n\n"); | |
1368 | lockdep_print_held_locks(curr); | |
1369 | ||
24208ca7 ML |
1370 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1371 | printk(" and the holding lock:\n"); | |
1372 | if (!save_trace(&prev_root->trace)) | |
1373 | return 0; | |
1374 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1375 | |
24208ca7 ML |
1376 | printk("\nthe dependencies between the lock to be acquired"); |
1377 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1378 | if (!save_trace(&next_root->trace)) | |
1379 | return 0; | |
1380 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1381 | |
1382 | printk("\nstack backtrace:\n"); | |
1383 | dump_stack(); | |
1384 | ||
1385 | return 0; | |
1386 | } | |
1387 | ||
1388 | static int | |
1389 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1390 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1391 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1392 | { | |
1393 | int ret; | |
24208ca7 | 1394 | struct lock_list this, that; |
d7aaba14 | 1395 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1396 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1397 | |
1398 | this.parent = NULL; | |
1399 | ||
1400 | this.class = hlock_class(prev); | |
1401 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1402 | if (ret < 0) |
1403 | return print_bfs_bug(ret); | |
1404 | if (ret == 1) | |
1405 | return ret; | |
d7aaba14 | 1406 | |
24208ca7 ML |
1407 | that.parent = NULL; |
1408 | that.class = hlock_class(next); | |
1409 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1410 | if (ret < 0) |
1411 | return print_bfs_bug(ret); | |
1412 | if (ret == 1) | |
1413 | return ret; | |
fbb9ce95 | 1414 | |
24208ca7 ML |
1415 | return print_bad_irq_dependency(curr, &this, &that, |
1416 | target_entry, target_entry1, | |
1417 | prev, next, | |
fbb9ce95 IM |
1418 | bit_backwards, bit_forwards, irqclass); |
1419 | } | |
1420 | ||
4f367d8a PZ |
1421 | static const char *state_names[] = { |
1422 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1423 | __stringify(__STATE), |
4f367d8a PZ |
1424 | #include "lockdep_states.h" |
1425 | #undef LOCKDEP_STATE | |
1426 | }; | |
1427 | ||
1428 | static const char *state_rnames[] = { | |
1429 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1430 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1431 | #include "lockdep_states.h" |
1432 | #undef LOCKDEP_STATE | |
1433 | }; | |
1434 | ||
1435 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1436 | { |
4f367d8a PZ |
1437 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1438 | } | |
8e18257d | 1439 | |
4f367d8a PZ |
1440 | static int exclusive_bit(int new_bit) |
1441 | { | |
8e18257d | 1442 | /* |
4f367d8a PZ |
1443 | * USED_IN |
1444 | * USED_IN_READ | |
1445 | * ENABLED | |
1446 | * ENABLED_READ | |
1447 | * | |
1448 | * bit 0 - write/read | |
1449 | * bit 1 - used_in/enabled | |
1450 | * bit 2+ state | |
8e18257d | 1451 | */ |
4f367d8a PZ |
1452 | |
1453 | int state = new_bit & ~3; | |
1454 | int dir = new_bit & 2; | |
8e18257d PZ |
1455 | |
1456 | /* | |
4f367d8a | 1457 | * keep state, bit flip the direction and strip read. |
8e18257d | 1458 | */ |
4f367d8a PZ |
1459 | return state | (dir ^ 2); |
1460 | } | |
1461 | ||
1462 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1463 | struct held_lock *next, enum lock_usage_bit bit) | |
1464 | { | |
8e18257d | 1465 | /* |
4f367d8a PZ |
1466 | * Prove that the new dependency does not connect a hardirq-safe |
1467 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1468 | * the backwards-subgraph starting at <prev>, and the |
1469 | * forwards-subgraph starting at <next>: | |
1470 | */ | |
4f367d8a PZ |
1471 | if (!check_usage(curr, prev, next, bit, |
1472 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1473 | return 0; |
1474 | ||
4f367d8a PZ |
1475 | bit++; /* _READ */ |
1476 | ||
cf40bd16 | 1477 | /* |
4f367d8a PZ |
1478 | * Prove that the new dependency does not connect a hardirq-safe-read |
1479 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1480 | * the backwards-subgraph starting at <prev>, and the |
1481 | * forwards-subgraph starting at <next>: | |
1482 | */ | |
4f367d8a PZ |
1483 | if (!check_usage(curr, prev, next, bit, |
1484 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1485 | return 0; |
1486 | ||
4f367d8a PZ |
1487 | return 1; |
1488 | } | |
1489 | ||
1490 | static int | |
1491 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1492 | struct held_lock *next) | |
1493 | { | |
1494 | #define LOCKDEP_STATE(__STATE) \ | |
1495 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1496 | return 0; |
4f367d8a PZ |
1497 | #include "lockdep_states.h" |
1498 | #undef LOCKDEP_STATE | |
cf40bd16 | 1499 | |
8e18257d PZ |
1500 | return 1; |
1501 | } | |
1502 | ||
1503 | static void inc_chains(void) | |
1504 | { | |
1505 | if (current->hardirq_context) | |
1506 | nr_hardirq_chains++; | |
1507 | else { | |
1508 | if (current->softirq_context) | |
1509 | nr_softirq_chains++; | |
1510 | else | |
1511 | nr_process_chains++; | |
1512 | } | |
1513 | } | |
1514 | ||
1515 | #else | |
1516 | ||
1517 | static inline int | |
1518 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1519 | struct held_lock *next) | |
1520 | { | |
1521 | return 1; | |
1522 | } | |
1523 | ||
1524 | static inline void inc_chains(void) | |
1525 | { | |
1526 | nr_process_chains++; | |
1527 | } | |
1528 | ||
fbb9ce95 IM |
1529 | #endif |
1530 | ||
1531 | static int | |
1532 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1533 | struct held_lock *next) | |
1534 | { | |
74c383f1 | 1535 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1536 | return 0; |
1537 | ||
1538 | printk("\n=============================================\n"); | |
1539 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1540 | print_kernel_version(); |
fbb9ce95 IM |
1541 | printk( "---------------------------------------------\n"); |
1542 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1543 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1544 | print_lock(next); |
1545 | printk("\nbut task is already holding lock:\n"); | |
1546 | print_lock(prev); | |
1547 | ||
1548 | printk("\nother info that might help us debug this:\n"); | |
1549 | lockdep_print_held_locks(curr); | |
1550 | ||
1551 | printk("\nstack backtrace:\n"); | |
1552 | dump_stack(); | |
1553 | ||
1554 | return 0; | |
1555 | } | |
1556 | ||
1557 | /* | |
1558 | * Check whether we are holding such a class already. | |
1559 | * | |
1560 | * (Note that this has to be done separately, because the graph cannot | |
1561 | * detect such classes of deadlocks.) | |
1562 | * | |
1563 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1564 | */ | |
1565 | static int | |
1566 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1567 | struct lockdep_map *next_instance, int read) | |
1568 | { | |
1569 | struct held_lock *prev; | |
7531e2f3 | 1570 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1571 | int i; |
1572 | ||
1573 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1574 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1575 | |
1576 | if (prev->instance == next->nest_lock) | |
1577 | nest = prev; | |
1578 | ||
f82b217e | 1579 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1580 | continue; |
7531e2f3 | 1581 | |
fbb9ce95 IM |
1582 | /* |
1583 | * Allow read-after-read recursion of the same | |
6c9076ec | 1584 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1585 | */ |
6c9076ec | 1586 | if ((read == 2) && prev->read) |
fbb9ce95 | 1587 | return 2; |
7531e2f3 PZ |
1588 | |
1589 | /* | |
1590 | * We're holding the nest_lock, which serializes this lock's | |
1591 | * nesting behaviour. | |
1592 | */ | |
1593 | if (nest) | |
1594 | return 2; | |
1595 | ||
fbb9ce95 IM |
1596 | return print_deadlock_bug(curr, prev, next); |
1597 | } | |
1598 | return 1; | |
1599 | } | |
1600 | ||
1601 | /* | |
1602 | * There was a chain-cache miss, and we are about to add a new dependency | |
1603 | * to a previous lock. We recursively validate the following rules: | |
1604 | * | |
1605 | * - would the adding of the <prev> -> <next> dependency create a | |
1606 | * circular dependency in the graph? [== circular deadlock] | |
1607 | * | |
1608 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1609 | * (in the full backwards-subgraph starting at <prev>) with any | |
1610 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1611 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1612 | * | |
1613 | * - does the new prev->next dependency connect any softirq-safe lock | |
1614 | * (in the full backwards-subgraph starting at <prev>) with any | |
1615 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1616 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1617 | * | |
1618 | * any of these scenarios could lead to a deadlock. | |
1619 | * | |
1620 | * Then if all the validations pass, we add the forwards and backwards | |
1621 | * dependency. | |
1622 | */ | |
1623 | static int | |
1624 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1625 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1626 | { |
1627 | struct lock_list *entry; | |
1628 | int ret; | |
db0002a3 ML |
1629 | struct lock_list this; |
1630 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 IM |
1631 | |
1632 | /* | |
1633 | * Prove that the new <prev> -> <next> dependency would not | |
1634 | * create a circular dependency in the graph. (We do this by | |
1635 | * forward-recursing into the graph starting at <next>, and | |
1636 | * checking whether we can reach <prev>.) | |
1637 | * | |
1638 | * We are using global variables to control the recursion, to | |
1639 | * keep the stackframe size of the recursive functions low: | |
1640 | */ | |
db0002a3 ML |
1641 | this.class = hlock_class(next); |
1642 | this.parent = NULL; | |
1643 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1644 | if (unlikely(!ret)) | |
1645 | return print_circular_bug(&this, target_entry, next, prev); | |
1646 | else if (unlikely(ret < 0)) | |
1647 | return print_bfs_bug(ret); | |
c94aa5ca | 1648 | |
8e18257d | 1649 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1650 | return 0; |
1651 | ||
fbb9ce95 IM |
1652 | /* |
1653 | * For recursive read-locks we do all the dependency checks, | |
1654 | * but we dont store read-triggered dependencies (only | |
1655 | * write-triggered dependencies). This ensures that only the | |
1656 | * write-side dependencies matter, and that if for example a | |
1657 | * write-lock never takes any other locks, then the reads are | |
1658 | * equivalent to a NOP. | |
1659 | */ | |
1660 | if (next->read == 2 || prev->read == 2) | |
1661 | return 1; | |
1662 | /* | |
1663 | * Is the <prev> -> <next> dependency already present? | |
1664 | * | |
1665 | * (this may occur even though this is a new chain: consider | |
1666 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1667 | * chains - the second one will be new, but L1 already has | |
1668 | * L2 added to its dependency list, due to the first chain.) | |
1669 | */ | |
f82b217e DJ |
1670 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1671 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1672 | if (distance == 1) |
1673 | entry->distance = 1; | |
fbb9ce95 | 1674 | return 2; |
068135e6 | 1675 | } |
fbb9ce95 IM |
1676 | } |
1677 | ||
1678 | /* | |
1679 | * Ok, all validations passed, add the new lock | |
1680 | * to the previous lock's dependency list: | |
1681 | */ | |
f82b217e DJ |
1682 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1683 | &hlock_class(prev)->locks_after, | |
1684 | next->acquire_ip, distance); | |
068135e6 | 1685 | |
fbb9ce95 IM |
1686 | if (!ret) |
1687 | return 0; | |
910b1b2e | 1688 | |
f82b217e DJ |
1689 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1690 | &hlock_class(next)->locks_before, | |
1691 | next->acquire_ip, distance); | |
910b1b2e JP |
1692 | if (!ret) |
1693 | return 0; | |
fbb9ce95 IM |
1694 | |
1695 | /* | |
8e18257d PZ |
1696 | * Debugging printouts: |
1697 | */ | |
f82b217e | 1698 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1699 | graph_unlock(); |
1700 | printk("\n new dependency: "); | |
f82b217e | 1701 | print_lock_name(hlock_class(prev)); |
8e18257d | 1702 | printk(" => "); |
f82b217e | 1703 | print_lock_name(hlock_class(next)); |
8e18257d | 1704 | printk("\n"); |
fbb9ce95 | 1705 | dump_stack(); |
8e18257d | 1706 | return graph_lock(); |
fbb9ce95 | 1707 | } |
8e18257d PZ |
1708 | return 1; |
1709 | } | |
fbb9ce95 | 1710 | |
8e18257d PZ |
1711 | /* |
1712 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1713 | * The ones that are relevant are (in increasing distance from curr): | |
1714 | * all consecutive trylock entries and the final non-trylock entry - or | |
1715 | * the end of this context's lock-chain - whichever comes first. | |
1716 | */ | |
1717 | static int | |
1718 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1719 | { | |
1720 | int depth = curr->lockdep_depth; | |
1721 | struct held_lock *hlock; | |
d6d897ce | 1722 | |
fbb9ce95 | 1723 | /* |
8e18257d PZ |
1724 | * Debugging checks. |
1725 | * | |
1726 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1727 | */ |
8e18257d PZ |
1728 | if (!depth) |
1729 | goto out_bug; | |
fbb9ce95 | 1730 | /* |
8e18257d PZ |
1731 | * At least two relevant locks must exist for this |
1732 | * to be a head: | |
fbb9ce95 | 1733 | */ |
8e18257d PZ |
1734 | if (curr->held_locks[depth].irq_context != |
1735 | curr->held_locks[depth-1].irq_context) | |
1736 | goto out_bug; | |
74c383f1 | 1737 | |
8e18257d PZ |
1738 | for (;;) { |
1739 | int distance = curr->lockdep_depth - depth + 1; | |
1740 | hlock = curr->held_locks + depth-1; | |
1741 | /* | |
1742 | * Only non-recursive-read entries get new dependencies | |
1743 | * added: | |
1744 | */ | |
1745 | if (hlock->read != 2) { | |
1746 | if (!check_prev_add(curr, hlock, next, distance)) | |
1747 | return 0; | |
1748 | /* | |
1749 | * Stop after the first non-trylock entry, | |
1750 | * as non-trylock entries have added their | |
1751 | * own direct dependencies already, so this | |
1752 | * lock is connected to them indirectly: | |
1753 | */ | |
1754 | if (!hlock->trylock) | |
1755 | break; | |
74c383f1 | 1756 | } |
8e18257d PZ |
1757 | depth--; |
1758 | /* | |
1759 | * End of lock-stack? | |
1760 | */ | |
1761 | if (!depth) | |
1762 | break; | |
1763 | /* | |
1764 | * Stop the search if we cross into another context: | |
1765 | */ | |
1766 | if (curr->held_locks[depth].irq_context != | |
1767 | curr->held_locks[depth-1].irq_context) | |
1768 | break; | |
fbb9ce95 | 1769 | } |
8e18257d PZ |
1770 | return 1; |
1771 | out_bug: | |
1772 | if (!debug_locks_off_graph_unlock()) | |
1773 | return 0; | |
fbb9ce95 | 1774 | |
8e18257d | 1775 | WARN_ON(1); |
fbb9ce95 | 1776 | |
8e18257d | 1777 | return 0; |
fbb9ce95 IM |
1778 | } |
1779 | ||
8e18257d | 1780 | unsigned long nr_lock_chains; |
443cd507 | 1781 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1782 | int nr_chain_hlocks; |
443cd507 HY |
1783 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1784 | ||
1785 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1786 | { | |
1787 | return lock_classes + chain_hlocks[chain->base + i]; | |
1788 | } | |
8e18257d | 1789 | |
fbb9ce95 IM |
1790 | /* |
1791 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1792 | * add it and return 1 - in this case the new dependency chain is |
1793 | * validated. If the key is already hashed, return 0. | |
1794 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1795 | */ |
443cd507 HY |
1796 | static inline int lookup_chain_cache(struct task_struct *curr, |
1797 | struct held_lock *hlock, | |
1798 | u64 chain_key) | |
fbb9ce95 | 1799 | { |
f82b217e | 1800 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1801 | struct list_head *hash_head = chainhashentry(chain_key); |
1802 | struct lock_chain *chain; | |
443cd507 | 1803 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1804 | int i, j, n, cn; |
fbb9ce95 | 1805 | |
381a2292 JP |
1806 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1807 | return 0; | |
fbb9ce95 IM |
1808 | /* |
1809 | * We can walk it lock-free, because entries only get added | |
1810 | * to the hash: | |
1811 | */ | |
1812 | list_for_each_entry(chain, hash_head, entry) { | |
1813 | if (chain->chain_key == chain_key) { | |
1814 | cache_hit: | |
bd6d29c2 | 1815 | debug_atomic_inc(chain_lookup_hits); |
81fc685a | 1816 | if (very_verbose(class)) |
755cd900 AM |
1817 | printk("\nhash chain already cached, key: " |
1818 | "%016Lx tail class: [%p] %s\n", | |
1819 | (unsigned long long)chain_key, | |
1820 | class->key, class->name); | |
fbb9ce95 IM |
1821 | return 0; |
1822 | } | |
1823 | } | |
81fc685a | 1824 | if (very_verbose(class)) |
755cd900 AM |
1825 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1826 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1827 | /* |
1828 | * Allocate a new chain entry from the static array, and add | |
1829 | * it to the hash: | |
1830 | */ | |
74c383f1 IM |
1831 | if (!graph_lock()) |
1832 | return 0; | |
fbb9ce95 IM |
1833 | /* |
1834 | * We have to walk the chain again locked - to avoid duplicates: | |
1835 | */ | |
1836 | list_for_each_entry(chain, hash_head, entry) { | |
1837 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1838 | graph_unlock(); |
fbb9ce95 IM |
1839 | goto cache_hit; |
1840 | } | |
1841 | } | |
1842 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1843 | if (!debug_locks_off_graph_unlock()) |
1844 | return 0; | |
1845 | ||
fbb9ce95 IM |
1846 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1847 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 1848 | dump_stack(); |
fbb9ce95 IM |
1849 | return 0; |
1850 | } | |
1851 | chain = lock_chains + nr_lock_chains++; | |
1852 | chain->chain_key = chain_key; | |
443cd507 HY |
1853 | chain->irq_context = hlock->irq_context; |
1854 | /* Find the first held_lock of current chain */ | |
1855 | hlock_next = hlock; | |
1856 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1857 | hlock_curr = curr->held_locks + i; | |
1858 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1859 | break; | |
1860 | hlock_next = hlock; | |
1861 | } | |
1862 | i++; | |
1863 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1864 | cn = nr_chain_hlocks; |
1865 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1866 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1867 | if (n == cn) | |
1868 | break; | |
1869 | cn = n; | |
1870 | } | |
1871 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1872 | chain->base = cn; | |
443cd507 | 1873 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1874 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1875 | chain_hlocks[chain->base + j] = lock_id; |
1876 | } | |
1877 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1878 | } | |
fbb9ce95 | 1879 | list_add_tail_rcu(&chain->entry, hash_head); |
bd6d29c2 | 1880 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
1881 | inc_chains(); |
1882 | ||
1883 | return 1; | |
1884 | } | |
1885 | ||
1886 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1887 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1888 | { |
1889 | /* | |
1890 | * Trylock needs to maintain the stack of held locks, but it | |
1891 | * does not add new dependencies, because trylock can be done | |
1892 | * in any order. | |
1893 | * | |
1894 | * We look up the chain_key and do the O(N^2) check and update of | |
1895 | * the dependencies only if this is a new dependency chain. | |
1896 | * (If lookup_chain_cache() returns with 1 it acquires | |
1897 | * graph_lock for us) | |
1898 | */ | |
1899 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1900 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1901 | /* |
1902 | * Check whether last held lock: | |
1903 | * | |
1904 | * - is irq-safe, if this lock is irq-unsafe | |
1905 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1906 | * | |
1907 | * And check whether the new lock's dependency graph | |
1908 | * could lead back to the previous lock. | |
1909 | * | |
1910 | * any of these scenarios could lead to a deadlock. If | |
1911 | * All validations | |
1912 | */ | |
1913 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1914 | ||
1915 | if (!ret) | |
1916 | return 0; | |
1917 | /* | |
1918 | * Mark recursive read, as we jump over it when | |
1919 | * building dependencies (just like we jump over | |
1920 | * trylock entries): | |
1921 | */ | |
1922 | if (ret == 2) | |
1923 | hlock->read = 2; | |
1924 | /* | |
1925 | * Add dependency only if this lock is not the head | |
1926 | * of the chain, and if it's not a secondary read-lock: | |
1927 | */ | |
1928 | if (!chain_head && ret != 2) | |
1929 | if (!check_prevs_add(curr, hlock)) | |
1930 | return 0; | |
1931 | graph_unlock(); | |
1932 | } else | |
1933 | /* after lookup_chain_cache(): */ | |
1934 | if (unlikely(!debug_locks)) | |
1935 | return 0; | |
fbb9ce95 IM |
1936 | |
1937 | return 1; | |
1938 | } | |
8e18257d PZ |
1939 | #else |
1940 | static inline int validate_chain(struct task_struct *curr, | |
1941 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1942 | int chain_head, u64 chain_key) |
8e18257d PZ |
1943 | { |
1944 | return 1; | |
1945 | } | |
ca58abcb | 1946 | #endif |
fbb9ce95 IM |
1947 | |
1948 | /* | |
1949 | * We are building curr_chain_key incrementally, so double-check | |
1950 | * it from scratch, to make sure that it's done correctly: | |
1951 | */ | |
1d09daa5 | 1952 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1953 | { |
1954 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1955 | struct held_lock *hlock, *prev_hlock = NULL; | |
1956 | unsigned int i, id; | |
1957 | u64 chain_key = 0; | |
1958 | ||
1959 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1960 | hlock = curr->held_locks + i; | |
1961 | if (chain_key != hlock->prev_chain_key) { | |
1962 | debug_locks_off(); | |
2df8b1d6 | 1963 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1964 | curr->lockdep_depth, i, |
1965 | (unsigned long long)chain_key, | |
1966 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1967 | return; |
1968 | } | |
f82b217e | 1969 | id = hlock->class_idx - 1; |
381a2292 JP |
1970 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1971 | return; | |
1972 | ||
fbb9ce95 IM |
1973 | if (prev_hlock && (prev_hlock->irq_context != |
1974 | hlock->irq_context)) | |
1975 | chain_key = 0; | |
1976 | chain_key = iterate_chain_key(chain_key, id); | |
1977 | prev_hlock = hlock; | |
1978 | } | |
1979 | if (chain_key != curr->curr_chain_key) { | |
1980 | debug_locks_off(); | |
2df8b1d6 | 1981 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1982 | curr->lockdep_depth, i, |
1983 | (unsigned long long)chain_key, | |
1984 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1985 | } |
1986 | #endif | |
1987 | } | |
1988 | ||
8e18257d PZ |
1989 | static int |
1990 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1991 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1992 | { | |
1993 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1994 | return 0; | |
1995 | ||
1996 | printk("\n=================================\n"); | |
1997 | printk( "[ INFO: inconsistent lock state ]\n"); | |
1998 | print_kernel_version(); | |
1999 | printk( "---------------------------------\n"); | |
2000 | ||
2001 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2002 | usage_str[prev_bit], usage_str[new_bit]); | |
2003 | ||
2004 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2005 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2006 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2007 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2008 | trace_hardirqs_enabled(curr), | |
2009 | trace_softirqs_enabled(curr)); | |
2010 | print_lock(this); | |
2011 | ||
2012 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2013 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2014 | |
2015 | print_irqtrace_events(curr); | |
2016 | printk("\nother info that might help us debug this:\n"); | |
2017 | lockdep_print_held_locks(curr); | |
2018 | ||
2019 | printk("\nstack backtrace:\n"); | |
2020 | dump_stack(); | |
2021 | ||
2022 | return 0; | |
2023 | } | |
2024 | ||
2025 | /* | |
2026 | * Print out an error if an invalid bit is set: | |
2027 | */ | |
2028 | static inline int | |
2029 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2030 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2031 | { | |
f82b217e | 2032 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2033 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2034 | return 1; | |
2035 | } | |
2036 | ||
2037 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2038 | enum lock_usage_bit new_bit); | |
2039 | ||
81d68a96 | 2040 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2041 | |
2042 | /* | |
2043 | * print irq inversion bug: | |
2044 | */ | |
2045 | static int | |
24208ca7 ML |
2046 | print_irq_inversion_bug(struct task_struct *curr, |
2047 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2048 | struct held_lock *this, int forwards, |
2049 | const char *irqclass) | |
2050 | { | |
74c383f1 | 2051 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2052 | return 0; |
2053 | ||
2054 | printk("\n=========================================================\n"); | |
2055 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2056 | print_kernel_version(); |
fbb9ce95 IM |
2057 | printk( "---------------------------------------------------------\n"); |
2058 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2059 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2060 | print_lock(this); |
2061 | if (forwards) | |
26575e28 | 2062 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2063 | else |
26575e28 | 2064 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2065 | print_lock_name(other->class); |
fbb9ce95 IM |
2066 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2067 | ||
2068 | printk("\nother info that might help us debug this:\n"); | |
2069 | lockdep_print_held_locks(curr); | |
2070 | ||
24208ca7 ML |
2071 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2072 | if (!save_trace(&root->trace)) | |
2073 | return 0; | |
2074 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2075 | |
2076 | printk("\nstack backtrace:\n"); | |
2077 | dump_stack(); | |
2078 | ||
2079 | return 0; | |
2080 | } | |
2081 | ||
2082 | /* | |
2083 | * Prove that in the forwards-direction subgraph starting at <this> | |
2084 | * there is no lock matching <mask>: | |
2085 | */ | |
2086 | static int | |
2087 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2088 | enum lock_usage_bit bit, const char *irqclass) | |
2089 | { | |
2090 | int ret; | |
d7aaba14 ML |
2091 | struct lock_list root; |
2092 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2093 | |
d7aaba14 ML |
2094 | root.parent = NULL; |
2095 | root.class = hlock_class(this); | |
2096 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2097 | if (ret < 0) |
2098 | return print_bfs_bug(ret); | |
2099 | if (ret == 1) | |
2100 | return ret; | |
fbb9ce95 | 2101 | |
24208ca7 | 2102 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2103 | this, 1, irqclass); |
fbb9ce95 IM |
2104 | } |
2105 | ||
2106 | /* | |
2107 | * Prove that in the backwards-direction subgraph starting at <this> | |
2108 | * there is no lock matching <mask>: | |
2109 | */ | |
2110 | static int | |
2111 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2112 | enum lock_usage_bit bit, const char *irqclass) | |
2113 | { | |
2114 | int ret; | |
d7aaba14 ML |
2115 | struct lock_list root; |
2116 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2117 | |
d7aaba14 ML |
2118 | root.parent = NULL; |
2119 | root.class = hlock_class(this); | |
2120 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2121 | if (ret < 0) |
2122 | return print_bfs_bug(ret); | |
2123 | if (ret == 1) | |
2124 | return ret; | |
fbb9ce95 | 2125 | |
24208ca7 | 2126 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2127 | this, 0, irqclass); |
fbb9ce95 IM |
2128 | } |
2129 | ||
3117df04 | 2130 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2131 | { |
2132 | printk("irq event stamp: %u\n", curr->irq_events); | |
2133 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2134 | print_ip_sym(curr->hardirq_enable_ip); | |
2135 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2136 | print_ip_sym(curr->hardirq_disable_ip); | |
2137 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2138 | print_ip_sym(curr->softirq_enable_ip); | |
2139 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2140 | print_ip_sym(curr->softirq_disable_ip); | |
2141 | } | |
2142 | ||
cd95302d | 2143 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2144 | { |
8e18257d PZ |
2145 | #if HARDIRQ_VERBOSE |
2146 | return class_filter(class); | |
2147 | #endif | |
fbb9ce95 IM |
2148 | return 0; |
2149 | } | |
2150 | ||
cd95302d | 2151 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2152 | { |
8e18257d PZ |
2153 | #if SOFTIRQ_VERBOSE |
2154 | return class_filter(class); | |
2155 | #endif | |
2156 | return 0; | |
fbb9ce95 IM |
2157 | } |
2158 | ||
cd95302d | 2159 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2160 | { |
2161 | #if RECLAIM_VERBOSE | |
2162 | return class_filter(class); | |
2163 | #endif | |
2164 | return 0; | |
2165 | } | |
2166 | ||
fbb9ce95 IM |
2167 | #define STRICT_READ_CHECKS 1 |
2168 | ||
cd95302d PZ |
2169 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2170 | #define LOCKDEP_STATE(__STATE) \ | |
2171 | __STATE##_verbose, | |
2172 | #include "lockdep_states.h" | |
2173 | #undef LOCKDEP_STATE | |
2174 | }; | |
2175 | ||
2176 | static inline int state_verbose(enum lock_usage_bit bit, | |
2177 | struct lock_class *class) | |
2178 | { | |
2179 | return state_verbose_f[bit >> 2](class); | |
2180 | } | |
2181 | ||
42c50d54 PZ |
2182 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2183 | enum lock_usage_bit bit, const char *name); | |
2184 | ||
6a6904d3 | 2185 | static int |
1c21f14e PZ |
2186 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2187 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2188 | { |
f989209e | 2189 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2190 | int read = new_bit & 1; |
42c50d54 PZ |
2191 | int dir = new_bit & 2; |
2192 | ||
38aa2714 PZ |
2193 | /* |
2194 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2195 | * has ENABLED state, which would allow recursion deadlocks. | |
2196 | * | |
2197 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2198 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2199 | */ | |
42c50d54 PZ |
2200 | check_usage_f usage = dir ? |
2201 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2202 | |
38aa2714 PZ |
2203 | /* |
2204 | * Validate that this particular lock does not have conflicting | |
2205 | * usage states. | |
2206 | */ | |
6a6904d3 PZ |
2207 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2208 | return 0; | |
42c50d54 | 2209 | |
38aa2714 PZ |
2210 | /* |
2211 | * Validate that the lock dependencies don't have conflicting usage | |
2212 | * states. | |
2213 | */ | |
2214 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2215 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2216 | return 0; |
780e820b | 2217 | |
38aa2714 PZ |
2218 | /* |
2219 | * Check for read in write conflicts | |
2220 | */ | |
2221 | if (!read) { | |
2222 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2223 | return 0; | |
2224 | ||
2225 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2226 | !usage(curr, this, excl_bit + 1, |
2227 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2228 | return 0; |
2229 | } | |
780e820b | 2230 | |
cd95302d | 2231 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2232 | return 2; |
2233 | ||
2234 | return 1; | |
2235 | } | |
2236 | ||
cf40bd16 | 2237 | enum mark_type { |
36bfb9bb PZ |
2238 | #define LOCKDEP_STATE(__STATE) __STATE, |
2239 | #include "lockdep_states.h" | |
2240 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2241 | }; |
2242 | ||
fbb9ce95 IM |
2243 | /* |
2244 | * Mark all held locks with a usage bit: | |
2245 | */ | |
1d09daa5 | 2246 | static int |
cf40bd16 | 2247 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2248 | { |
2249 | enum lock_usage_bit usage_bit; | |
2250 | struct held_lock *hlock; | |
2251 | int i; | |
2252 | ||
2253 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2254 | hlock = curr->held_locks + i; | |
2255 | ||
cf2ad4d1 PZ |
2256 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2257 | if (hlock->read) | |
2258 | usage_bit += 1; /* READ */ | |
2259 | ||
2260 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2261 | |
4ff773bb | 2262 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2263 | return 0; |
2264 | } | |
2265 | ||
2266 | return 1; | |
2267 | } | |
2268 | ||
2269 | /* | |
2270 | * Debugging helper: via this flag we know that we are in | |
2271 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2272 | */ | |
2273 | static int early_boot_irqs_enabled; | |
2274 | ||
2275 | void early_boot_irqs_off(void) | |
2276 | { | |
2277 | early_boot_irqs_enabled = 0; | |
2278 | } | |
2279 | ||
2280 | void early_boot_irqs_on(void) | |
2281 | { | |
2282 | early_boot_irqs_enabled = 1; | |
2283 | } | |
2284 | ||
2285 | /* | |
2286 | * Hardirqs will be enabled: | |
2287 | */ | |
6afe40b4 | 2288 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2289 | { |
2290 | struct task_struct *curr = current; | |
fbb9ce95 | 2291 | |
6afe40b4 | 2292 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2293 | |
fbb9ce95 IM |
2294 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2295 | return; | |
2296 | ||
2297 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2298 | return; | |
2299 | ||
2300 | if (unlikely(curr->hardirqs_enabled)) { | |
8795d771 FW |
2301 | /* |
2302 | * Neither irq nor preemption are disabled here | |
2303 | * so this is racy by nature but loosing one hit | |
2304 | * in a stat is not a big deal. | |
2305 | */ | |
ba697f40 | 2306 | __debug_atomic_inc(redundant_hardirqs_on); |
fbb9ce95 IM |
2307 | return; |
2308 | } | |
2309 | /* we'll do an OFF -> ON transition: */ | |
2310 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2311 | |
2312 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2313 | return; | |
2314 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2315 | return; | |
2316 | /* | |
2317 | * We are going to turn hardirqs on, so set the | |
2318 | * usage bit for all held locks: | |
2319 | */ | |
cf40bd16 | 2320 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2321 | return; |
2322 | /* | |
2323 | * If we have softirqs enabled, then set the usage | |
2324 | * bit for all held locks. (disabled hardirqs prevented | |
2325 | * this bit from being set before) | |
2326 | */ | |
2327 | if (curr->softirqs_enabled) | |
cf40bd16 | 2328 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2329 | return; |
2330 | ||
8e18257d PZ |
2331 | curr->hardirq_enable_ip = ip; |
2332 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2333 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2334 | } |
81d68a96 | 2335 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2336 | |
1d09daa5 | 2337 | void trace_hardirqs_on(void) |
81d68a96 SR |
2338 | { |
2339 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2340 | } | |
8e18257d PZ |
2341 | EXPORT_SYMBOL(trace_hardirqs_on); |
2342 | ||
2343 | /* | |
2344 | * Hardirqs were disabled: | |
2345 | */ | |
6afe40b4 | 2346 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2347 | { |
2348 | struct task_struct *curr = current; | |
2349 | ||
6afe40b4 | 2350 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2351 | |
8e18257d PZ |
2352 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2353 | return; | |
2354 | ||
2355 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2356 | return; | |
2357 | ||
2358 | if (curr->hardirqs_enabled) { | |
2359 | /* | |
2360 | * We have done an ON -> OFF transition: | |
2361 | */ | |
2362 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2363 | curr->hardirq_disable_ip = ip; |
8e18257d | 2364 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2365 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2366 | } else |
bd6d29c2 | 2367 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2368 | } |
81d68a96 | 2369 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2370 | |
1d09daa5 | 2371 | void trace_hardirqs_off(void) |
81d68a96 SR |
2372 | { |
2373 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2374 | } | |
8e18257d PZ |
2375 | EXPORT_SYMBOL(trace_hardirqs_off); |
2376 | ||
2377 | /* | |
2378 | * Softirqs will be enabled: | |
2379 | */ | |
2380 | void trace_softirqs_on(unsigned long ip) | |
2381 | { | |
2382 | struct task_struct *curr = current; | |
2383 | ||
2384 | if (unlikely(!debug_locks)) | |
2385 | return; | |
2386 | ||
2387 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2388 | return; | |
2389 | ||
2390 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2391 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2392 | return; |
2393 | } | |
2394 | ||
2395 | /* | |
2396 | * We'll do an OFF -> ON transition: | |
2397 | */ | |
2398 | curr->softirqs_enabled = 1; | |
2399 | curr->softirq_enable_ip = ip; | |
2400 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2401 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2402 | /* |
2403 | * We are going to turn softirqs on, so set the | |
2404 | * usage bit for all held locks, if hardirqs are | |
2405 | * enabled too: | |
2406 | */ | |
2407 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2408 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2409 | } |
2410 | ||
2411 | /* | |
2412 | * Softirqs were disabled: | |
2413 | */ | |
2414 | void trace_softirqs_off(unsigned long ip) | |
2415 | { | |
2416 | struct task_struct *curr = current; | |
2417 | ||
2418 | if (unlikely(!debug_locks)) | |
2419 | return; | |
2420 | ||
2421 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2422 | return; | |
2423 | ||
2424 | if (curr->softirqs_enabled) { | |
2425 | /* | |
2426 | * We have done an ON -> OFF transition: | |
2427 | */ | |
2428 | curr->softirqs_enabled = 0; | |
2429 | curr->softirq_disable_ip = ip; | |
2430 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2431 | debug_atomic_inc(softirqs_off_events); |
8e18257d PZ |
2432 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2433 | } else | |
bd6d29c2 | 2434 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2435 | } |
2436 | ||
2f850181 | 2437 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2438 | { |
2439 | struct task_struct *curr = current; | |
2440 | ||
2441 | if (unlikely(!debug_locks)) | |
2442 | return; | |
2443 | ||
2444 | /* no reclaim without waiting on it */ | |
2445 | if (!(gfp_mask & __GFP_WAIT)) | |
2446 | return; | |
2447 | ||
2448 | /* this guy won't enter reclaim */ | |
2449 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2450 | return; | |
2451 | ||
2452 | /* We're only interested __GFP_FS allocations for now */ | |
2453 | if (!(gfp_mask & __GFP_FS)) | |
2454 | return; | |
2455 | ||
2f850181 | 2456 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2457 | return; |
2458 | ||
2459 | mark_held_locks(curr, RECLAIM_FS); | |
2460 | } | |
2461 | ||
2f850181 PZ |
2462 | static void check_flags(unsigned long flags); |
2463 | ||
2464 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2465 | { | |
2466 | unsigned long flags; | |
2467 | ||
2468 | if (unlikely(current->lockdep_recursion)) | |
2469 | return; | |
2470 | ||
2471 | raw_local_irq_save(flags); | |
2472 | check_flags(flags); | |
2473 | current->lockdep_recursion = 1; | |
2474 | __lockdep_trace_alloc(gfp_mask, flags); | |
2475 | current->lockdep_recursion = 0; | |
2476 | raw_local_irq_restore(flags); | |
2477 | } | |
2478 | ||
8e18257d PZ |
2479 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2480 | { | |
2481 | /* | |
2482 | * If non-trylock use in a hardirq or softirq context, then | |
2483 | * mark the lock as used in these contexts: | |
2484 | */ | |
2485 | if (!hlock->trylock) { | |
2486 | if (hlock->read) { | |
2487 | if (curr->hardirq_context) | |
2488 | if (!mark_lock(curr, hlock, | |
2489 | LOCK_USED_IN_HARDIRQ_READ)) | |
2490 | return 0; | |
2491 | if (curr->softirq_context) | |
2492 | if (!mark_lock(curr, hlock, | |
2493 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2494 | return 0; | |
2495 | } else { | |
2496 | if (curr->hardirq_context) | |
2497 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2498 | return 0; | |
2499 | if (curr->softirq_context) | |
2500 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2501 | return 0; | |
2502 | } | |
2503 | } | |
2504 | if (!hlock->hardirqs_off) { | |
2505 | if (hlock->read) { | |
2506 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2507 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2508 | return 0; |
2509 | if (curr->softirqs_enabled) | |
2510 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2511 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2512 | return 0; |
2513 | } else { | |
2514 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2515 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2516 | return 0; |
2517 | if (curr->softirqs_enabled) | |
2518 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2519 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2520 | return 0; |
2521 | } | |
2522 | } | |
2523 | ||
cf40bd16 NP |
2524 | /* |
2525 | * We reuse the irq context infrastructure more broadly as a general | |
2526 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2527 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2528 | * allocation). | |
2529 | */ | |
2530 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2531 | if (hlock->read) { | |
2532 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2533 | return 0; | |
2534 | } else { | |
2535 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2536 | return 0; | |
2537 | } | |
2538 | } | |
2539 | ||
8e18257d PZ |
2540 | return 1; |
2541 | } | |
2542 | ||
2543 | static int separate_irq_context(struct task_struct *curr, | |
2544 | struct held_lock *hlock) | |
2545 | { | |
2546 | unsigned int depth = curr->lockdep_depth; | |
2547 | ||
2548 | /* | |
2549 | * Keep track of points where we cross into an interrupt context: | |
2550 | */ | |
2551 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2552 | curr->softirq_context; | |
2553 | if (depth) { | |
2554 | struct held_lock *prev_hlock; | |
2555 | ||
2556 | prev_hlock = curr->held_locks + depth-1; | |
2557 | /* | |
2558 | * If we cross into another context, reset the | |
2559 | * hash key (this also prevents the checking and the | |
2560 | * adding of the dependency to 'prev'): | |
2561 | */ | |
2562 | if (prev_hlock->irq_context != hlock->irq_context) | |
2563 | return 1; | |
2564 | } | |
2565 | return 0; | |
fbb9ce95 IM |
2566 | } |
2567 | ||
8e18257d | 2568 | #else |
fbb9ce95 | 2569 | |
8e18257d PZ |
2570 | static inline |
2571 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2572 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2573 | { |
8e18257d PZ |
2574 | WARN_ON(1); |
2575 | return 1; | |
2576 | } | |
fbb9ce95 | 2577 | |
8e18257d PZ |
2578 | static inline int mark_irqflags(struct task_struct *curr, |
2579 | struct held_lock *hlock) | |
2580 | { | |
2581 | return 1; | |
2582 | } | |
fbb9ce95 | 2583 | |
8e18257d PZ |
2584 | static inline int separate_irq_context(struct task_struct *curr, |
2585 | struct held_lock *hlock) | |
2586 | { | |
2587 | return 0; | |
fbb9ce95 IM |
2588 | } |
2589 | ||
868a23a8 PZ |
2590 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2591 | { | |
2592 | } | |
2593 | ||
8e18257d | 2594 | #endif |
fbb9ce95 IM |
2595 | |
2596 | /* | |
8e18257d | 2597 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2598 | */ |
1d09daa5 | 2599 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2600 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2601 | { |
8e18257d | 2602 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2603 | |
2604 | /* | |
8e18257d PZ |
2605 | * If already set then do not dirty the cacheline, |
2606 | * nor do any checks: | |
fbb9ce95 | 2607 | */ |
f82b217e | 2608 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2609 | return 1; |
2610 | ||
2611 | if (!graph_lock()) | |
2612 | return 0; | |
fbb9ce95 | 2613 | /* |
8e18257d | 2614 | * Make sure we didnt race: |
fbb9ce95 | 2615 | */ |
f82b217e | 2616 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2617 | graph_unlock(); |
2618 | return 1; | |
2619 | } | |
fbb9ce95 | 2620 | |
f82b217e | 2621 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2622 | |
f82b217e | 2623 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2624 | return 0; |
fbb9ce95 | 2625 | |
8e18257d | 2626 | switch (new_bit) { |
5346417e PZ |
2627 | #define LOCKDEP_STATE(__STATE) \ |
2628 | case LOCK_USED_IN_##__STATE: \ | |
2629 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2630 | case LOCK_ENABLED_##__STATE: \ | |
2631 | case LOCK_ENABLED_##__STATE##_READ: | |
2632 | #include "lockdep_states.h" | |
2633 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2634 | ret = mark_lock_irq(curr, this, new_bit); |
2635 | if (!ret) | |
2636 | return 0; | |
2637 | break; | |
2638 | case LOCK_USED: | |
bd6d29c2 | 2639 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
2640 | break; |
2641 | default: | |
2642 | if (!debug_locks_off_graph_unlock()) | |
2643 | return 0; | |
2644 | WARN_ON(1); | |
2645 | return 0; | |
2646 | } | |
fbb9ce95 | 2647 | |
8e18257d PZ |
2648 | graph_unlock(); |
2649 | ||
2650 | /* | |
2651 | * We must printk outside of the graph_lock: | |
2652 | */ | |
2653 | if (ret == 2) { | |
2654 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2655 | print_lock(this); | |
2656 | print_irqtrace_events(curr); | |
2657 | dump_stack(); | |
2658 | } | |
2659 | ||
2660 | return ret; | |
2661 | } | |
fbb9ce95 IM |
2662 | |
2663 | /* | |
2664 | * Initialize a lock instance's lock-class mapping info: | |
2665 | */ | |
2666 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2667 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2668 | { |
c8a25005 PZ |
2669 | lock->class_cache = NULL; |
2670 | #ifdef CONFIG_LOCK_STAT | |
2671 | lock->cpu = raw_smp_processor_id(); | |
2672 | #endif | |
2673 | ||
2674 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2675 | lock->name = "NULL"; | |
fbb9ce95 | 2676 | return; |
c8a25005 PZ |
2677 | } |
2678 | ||
2679 | lock->name = name; | |
fbb9ce95 IM |
2680 | |
2681 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2682 | return; | |
fbb9ce95 IM |
2683 | /* |
2684 | * Sanity check, the lock-class key must be persistent: | |
2685 | */ | |
2686 | if (!static_obj(key)) { | |
2687 | printk("BUG: key %p not in .data!\n", key); | |
2688 | DEBUG_LOCKS_WARN_ON(1); | |
2689 | return; | |
2690 | } | |
fbb9ce95 | 2691 | lock->key = key; |
c8a25005 PZ |
2692 | |
2693 | if (unlikely(!debug_locks)) | |
2694 | return; | |
2695 | ||
4dfbb9d8 PZ |
2696 | if (subclass) |
2697 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2698 | } |
fbb9ce95 IM |
2699 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2700 | ||
2701 | /* | |
2702 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2703 | * We maintain the dependency maps and validate the locking attempt: | |
2704 | */ | |
2705 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2706 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
2707 | struct lockdep_map *nest_lock, unsigned long ip, |
2708 | int references) | |
fbb9ce95 IM |
2709 | { |
2710 | struct task_struct *curr = current; | |
d6d897ce | 2711 | struct lock_class *class = NULL; |
fbb9ce95 | 2712 | struct held_lock *hlock; |
fbb9ce95 IM |
2713 | unsigned int depth, id; |
2714 | int chain_head = 0; | |
bb97a91e | 2715 | int class_idx; |
fbb9ce95 IM |
2716 | u64 chain_key; |
2717 | ||
f20786ff PZ |
2718 | if (!prove_locking) |
2719 | check = 1; | |
2720 | ||
fbb9ce95 IM |
2721 | if (unlikely(!debug_locks)) |
2722 | return 0; | |
2723 | ||
2724 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2725 | return 0; | |
2726 | ||
2727 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2728 | debug_locks_off(); | |
2729 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2730 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2731 | dump_stack(); |
fbb9ce95 IM |
2732 | return 0; |
2733 | } | |
2734 | ||
d6d897ce IM |
2735 | if (!subclass) |
2736 | class = lock->class_cache; | |
2737 | /* | |
2738 | * Not cached yet or subclass? | |
2739 | */ | |
fbb9ce95 | 2740 | if (unlikely(!class)) { |
4dfbb9d8 | 2741 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2742 | if (!class) |
2743 | return 0; | |
2744 | } | |
bd6d29c2 | 2745 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
2746 | if (very_verbose(class)) { |
2747 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2748 | if (class->name_version > 1) | |
2749 | printk("#%d", class->name_version); | |
2750 | printk("\n"); | |
2751 | dump_stack(); | |
2752 | } | |
2753 | ||
2754 | /* | |
2755 | * Add the lock to the list of currently held locks. | |
2756 | * (we dont increase the depth just yet, up until the | |
2757 | * dependency checks are done) | |
2758 | */ | |
2759 | depth = curr->lockdep_depth; | |
2760 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2761 | return 0; | |
2762 | ||
bb97a91e PZ |
2763 | class_idx = class - lock_classes + 1; |
2764 | ||
2765 | if (depth) { | |
2766 | hlock = curr->held_locks + depth - 1; | |
2767 | if (hlock->class_idx == class_idx && nest_lock) { | |
2768 | if (hlock->references) | |
2769 | hlock->references++; | |
2770 | else | |
2771 | hlock->references = 2; | |
2772 | ||
2773 | return 1; | |
2774 | } | |
2775 | } | |
2776 | ||
fbb9ce95 | 2777 | hlock = curr->held_locks + depth; |
f82b217e DJ |
2778 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2779 | return 0; | |
bb97a91e | 2780 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
2781 | hlock->acquire_ip = ip; |
2782 | hlock->instance = lock; | |
7531e2f3 | 2783 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2784 | hlock->trylock = trylock; |
2785 | hlock->read = read; | |
2786 | hlock->check = check; | |
6951b12a | 2787 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 2788 | hlock->references = references; |
f20786ff PZ |
2789 | #ifdef CONFIG_LOCK_STAT |
2790 | hlock->waittime_stamp = 0; | |
3365e779 | 2791 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 2792 | #endif |
fbb9ce95 | 2793 | |
8e18257d PZ |
2794 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2795 | return 0; | |
2796 | ||
fbb9ce95 | 2797 | /* mark it as used: */ |
4ff773bb | 2798 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2799 | return 0; |
8e18257d | 2800 | |
fbb9ce95 | 2801 | /* |
17aacfb9 | 2802 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2803 | * lock keys along the dependency chain. We save the hash value |
2804 | * at every step so that we can get the current hash easily | |
2805 | * after unlock. The chain hash is then used to cache dependency | |
2806 | * results. | |
2807 | * | |
2808 | * The 'key ID' is what is the most compact key value to drive | |
2809 | * the hash, not class->key. | |
2810 | */ | |
2811 | id = class - lock_classes; | |
2812 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2813 | return 0; | |
2814 | ||
2815 | chain_key = curr->curr_chain_key; | |
2816 | if (!depth) { | |
2817 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2818 | return 0; | |
2819 | chain_head = 1; | |
2820 | } | |
2821 | ||
2822 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2823 | if (separate_irq_context(curr, hlock)) { |
2824 | chain_key = 0; | |
2825 | chain_head = 1; | |
fbb9ce95 | 2826 | } |
fbb9ce95 | 2827 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2828 | |
3aa416b0 | 2829 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2830 | return 0; |
381a2292 | 2831 | |
3aa416b0 | 2832 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2833 | curr->lockdep_depth++; |
2834 | check_chain_key(curr); | |
60e114d1 JP |
2835 | #ifdef CONFIG_DEBUG_LOCKDEP |
2836 | if (unlikely(!debug_locks)) | |
2837 | return 0; | |
2838 | #endif | |
fbb9ce95 IM |
2839 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2840 | debug_locks_off(); | |
2841 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2842 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2843 | dump_stack(); |
fbb9ce95 IM |
2844 | return 0; |
2845 | } | |
381a2292 | 2846 | |
fbb9ce95 IM |
2847 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2848 | max_lockdep_depth = curr->lockdep_depth; | |
2849 | ||
2850 | return 1; | |
2851 | } | |
2852 | ||
2853 | static int | |
2854 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2855 | unsigned long ip) | |
2856 | { | |
2857 | if (!debug_locks_off()) | |
2858 | return 0; | |
2859 | if (debug_locks_silent) | |
2860 | return 0; | |
2861 | ||
2862 | printk("\n=====================================\n"); | |
2863 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2864 | printk( "-------------------------------------\n"); | |
2865 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2866 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2867 | print_lockdep_cache(lock); |
2868 | printk(") at:\n"); | |
2869 | print_ip_sym(ip); | |
2870 | printk("but there are no more locks to release!\n"); | |
2871 | printk("\nother info that might help us debug this:\n"); | |
2872 | lockdep_print_held_locks(curr); | |
2873 | ||
2874 | printk("\nstack backtrace:\n"); | |
2875 | dump_stack(); | |
2876 | ||
2877 | return 0; | |
2878 | } | |
2879 | ||
2880 | /* | |
2881 | * Common debugging checks for both nested and non-nested unlock: | |
2882 | */ | |
2883 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2884 | unsigned long ip) | |
2885 | { | |
2886 | if (unlikely(!debug_locks)) | |
2887 | return 0; | |
2888 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2889 | return 0; | |
2890 | ||
2891 | if (curr->lockdep_depth <= 0) | |
2892 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2893 | ||
2894 | return 1; | |
2895 | } | |
2896 | ||
bb97a91e PZ |
2897 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
2898 | { | |
2899 | if (hlock->instance == lock) | |
2900 | return 1; | |
2901 | ||
2902 | if (hlock->references) { | |
2903 | struct lock_class *class = lock->class_cache; | |
2904 | ||
2905 | if (!class) | |
2906 | class = look_up_lock_class(lock, 0); | |
2907 | ||
2908 | if (DEBUG_LOCKS_WARN_ON(!class)) | |
2909 | return 0; | |
2910 | ||
2911 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) | |
2912 | return 0; | |
2913 | ||
2914 | if (hlock->class_idx == class - lock_classes + 1) | |
2915 | return 1; | |
2916 | } | |
2917 | ||
2918 | return 0; | |
2919 | } | |
2920 | ||
64aa348e | 2921 | static int |
00ef9f73 PZ |
2922 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2923 | struct lock_class_key *key, unsigned int subclass, | |
2924 | unsigned long ip) | |
64aa348e PZ |
2925 | { |
2926 | struct task_struct *curr = current; | |
2927 | struct held_lock *hlock, *prev_hlock; | |
2928 | struct lock_class *class; | |
2929 | unsigned int depth; | |
2930 | int i; | |
2931 | ||
2932 | depth = curr->lockdep_depth; | |
2933 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2934 | return 0; | |
2935 | ||
2936 | prev_hlock = NULL; | |
2937 | for (i = depth-1; i >= 0; i--) { | |
2938 | hlock = curr->held_locks + i; | |
2939 | /* | |
2940 | * We must not cross into another context: | |
2941 | */ | |
2942 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2943 | break; | |
bb97a91e | 2944 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
2945 | goto found_it; |
2946 | prev_hlock = hlock; | |
2947 | } | |
2948 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2949 | ||
2950 | found_it: | |
00ef9f73 | 2951 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2952 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2953 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2954 | |
2955 | curr->lockdep_depth = i; | |
2956 | curr->curr_chain_key = hlock->prev_chain_key; | |
2957 | ||
2958 | for (; i < depth; i++) { | |
2959 | hlock = curr->held_locks + i; | |
2960 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2961 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2962 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
2963 | hlock->nest_lock, hlock->acquire_ip, |
2964 | hlock->references)) | |
64aa348e PZ |
2965 | return 0; |
2966 | } | |
2967 | ||
2968 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2969 | return 0; | |
2970 | return 1; | |
2971 | } | |
2972 | ||
fbb9ce95 IM |
2973 | /* |
2974 | * Remove the lock to the list of currently held locks in a | |
2975 | * potentially non-nested (out of order) manner. This is a | |
2976 | * relatively rare operation, as all the unlock APIs default | |
2977 | * to nested mode (which uses lock_release()): | |
2978 | */ | |
2979 | static int | |
2980 | lock_release_non_nested(struct task_struct *curr, | |
2981 | struct lockdep_map *lock, unsigned long ip) | |
2982 | { | |
2983 | struct held_lock *hlock, *prev_hlock; | |
2984 | unsigned int depth; | |
2985 | int i; | |
2986 | ||
2987 | /* | |
2988 | * Check whether the lock exists in the current stack | |
2989 | * of held locks: | |
2990 | */ | |
2991 | depth = curr->lockdep_depth; | |
2992 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2993 | return 0; | |
2994 | ||
2995 | prev_hlock = NULL; | |
2996 | for (i = depth-1; i >= 0; i--) { | |
2997 | hlock = curr->held_locks + i; | |
2998 | /* | |
2999 | * We must not cross into another context: | |
3000 | */ | |
3001 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3002 | break; | |
bb97a91e | 3003 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3004 | goto found_it; |
3005 | prev_hlock = hlock; | |
3006 | } | |
3007 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3008 | ||
3009 | found_it: | |
bb97a91e PZ |
3010 | if (hlock->instance == lock) |
3011 | lock_release_holdtime(hlock); | |
3012 | ||
3013 | if (hlock->references) { | |
3014 | hlock->references--; | |
3015 | if (hlock->references) { | |
3016 | /* | |
3017 | * We had, and after removing one, still have | |
3018 | * references, the current lock stack is still | |
3019 | * valid. We're done! | |
3020 | */ | |
3021 | return 1; | |
3022 | } | |
3023 | } | |
f20786ff | 3024 | |
fbb9ce95 IM |
3025 | /* |
3026 | * We have the right lock to unlock, 'hlock' points to it. | |
3027 | * Now we remove it from the stack, and add back the other | |
3028 | * entries (if any), recalculating the hash along the way: | |
3029 | */ | |
bb97a91e | 3030 | |
fbb9ce95 IM |
3031 | curr->lockdep_depth = i; |
3032 | curr->curr_chain_key = hlock->prev_chain_key; | |
3033 | ||
3034 | for (i++; i < depth; i++) { | |
3035 | hlock = curr->held_locks + i; | |
3036 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3037 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3038 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3039 | hlock->nest_lock, hlock->acquire_ip, |
3040 | hlock->references)) | |
fbb9ce95 IM |
3041 | return 0; |
3042 | } | |
3043 | ||
3044 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
3045 | return 0; | |
3046 | return 1; | |
3047 | } | |
3048 | ||
3049 | /* | |
3050 | * Remove the lock to the list of currently held locks - this gets | |
3051 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3052 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3053 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3054 | */ | |
3055 | static int lock_release_nested(struct task_struct *curr, | |
3056 | struct lockdep_map *lock, unsigned long ip) | |
3057 | { | |
3058 | struct held_lock *hlock; | |
3059 | unsigned int depth; | |
3060 | ||
3061 | /* | |
3062 | * Pop off the top of the lock stack: | |
3063 | */ | |
3064 | depth = curr->lockdep_depth - 1; | |
3065 | hlock = curr->held_locks + depth; | |
3066 | ||
3067 | /* | |
3068 | * Is the unlock non-nested: | |
3069 | */ | |
bb97a91e | 3070 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3071 | return lock_release_non_nested(curr, lock, ip); |
3072 | curr->lockdep_depth--; | |
3073 | ||
3074 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
3075 | return 0; | |
3076 | ||
3077 | curr->curr_chain_key = hlock->prev_chain_key; | |
3078 | ||
f20786ff PZ |
3079 | lock_release_holdtime(hlock); |
3080 | ||
fbb9ce95 IM |
3081 | #ifdef CONFIG_DEBUG_LOCKDEP |
3082 | hlock->prev_chain_key = 0; | |
f82b217e | 3083 | hlock->class_idx = 0; |
fbb9ce95 IM |
3084 | hlock->acquire_ip = 0; |
3085 | hlock->irq_context = 0; | |
3086 | #endif | |
3087 | return 1; | |
3088 | } | |
3089 | ||
3090 | /* | |
3091 | * Remove the lock to the list of currently held locks - this gets | |
3092 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3093 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3094 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3095 | */ | |
3096 | static void | |
3097 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3098 | { | |
3099 | struct task_struct *curr = current; | |
3100 | ||
3101 | if (!check_unlock(curr, lock, ip)) | |
3102 | return; | |
3103 | ||
3104 | if (nested) { | |
3105 | if (!lock_release_nested(curr, lock, ip)) | |
3106 | return; | |
3107 | } else { | |
3108 | if (!lock_release_non_nested(curr, lock, ip)) | |
3109 | return; | |
3110 | } | |
3111 | ||
3112 | check_chain_key(curr); | |
3113 | } | |
3114 | ||
f607c668 PZ |
3115 | static int __lock_is_held(struct lockdep_map *lock) |
3116 | { | |
3117 | struct task_struct *curr = current; | |
3118 | int i; | |
3119 | ||
3120 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3121 | struct held_lock *hlock = curr->held_locks + i; |
3122 | ||
3123 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3124 | return 1; |
3125 | } | |
3126 | ||
3127 | return 0; | |
3128 | } | |
3129 | ||
fbb9ce95 IM |
3130 | /* |
3131 | * Check whether we follow the irq-flags state precisely: | |
3132 | */ | |
1d09daa5 | 3133 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3134 | { |
992860e9 IM |
3135 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3136 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3137 | if (!debug_locks) |
3138 | return; | |
3139 | ||
5f9fa8a6 IM |
3140 | if (irqs_disabled_flags(flags)) { |
3141 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3142 | printk("possible reason: unannotated irqs-off.\n"); | |
3143 | } | |
3144 | } else { | |
3145 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3146 | printk("possible reason: unannotated irqs-on.\n"); | |
3147 | } | |
3148 | } | |
fbb9ce95 IM |
3149 | |
3150 | /* | |
3151 | * We dont accurately track softirq state in e.g. | |
3152 | * hardirq contexts (such as on 4KSTACKS), so only | |
3153 | * check if not in hardirq contexts: | |
3154 | */ | |
3155 | if (!hardirq_count()) { | |
3156 | if (softirq_count()) | |
3157 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3158 | else | |
3159 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3160 | } | |
3161 | ||
3162 | if (!debug_locks) | |
3163 | print_irqtrace_events(current); | |
3164 | #endif | |
3165 | } | |
3166 | ||
00ef9f73 PZ |
3167 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3168 | struct lock_class_key *key, unsigned int subclass, | |
3169 | unsigned long ip) | |
64aa348e PZ |
3170 | { |
3171 | unsigned long flags; | |
3172 | ||
3173 | if (unlikely(current->lockdep_recursion)) | |
3174 | return; | |
3175 | ||
3176 | raw_local_irq_save(flags); | |
3177 | current->lockdep_recursion = 1; | |
3178 | check_flags(flags); | |
00ef9f73 | 3179 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3180 | check_chain_key(current); |
3181 | current->lockdep_recursion = 0; | |
3182 | raw_local_irq_restore(flags); | |
3183 | } | |
00ef9f73 | 3184 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3185 | |
fbb9ce95 IM |
3186 | /* |
3187 | * We are not always called with irqs disabled - do that here, | |
3188 | * and also avoid lockdep recursion: | |
3189 | */ | |
1d09daa5 | 3190 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3191 | int trylock, int read, int check, |
3192 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3193 | { |
3194 | unsigned long flags; | |
3195 | ||
3196 | if (unlikely(current->lockdep_recursion)) | |
3197 | return; | |
3198 | ||
3199 | raw_local_irq_save(flags); | |
3200 | check_flags(flags); | |
3201 | ||
3202 | current->lockdep_recursion = 1; | |
db2c4c77 | 3203 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3204 | __lock_acquire(lock, subclass, trylock, read, check, |
bb97a91e | 3205 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3206 | current->lockdep_recursion = 0; |
3207 | raw_local_irq_restore(flags); | |
3208 | } | |
fbb9ce95 IM |
3209 | EXPORT_SYMBOL_GPL(lock_acquire); |
3210 | ||
1d09daa5 | 3211 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3212 | unsigned long ip) |
fbb9ce95 IM |
3213 | { |
3214 | unsigned long flags; | |
3215 | ||
3216 | if (unlikely(current->lockdep_recursion)) | |
3217 | return; | |
3218 | ||
3219 | raw_local_irq_save(flags); | |
3220 | check_flags(flags); | |
3221 | current->lockdep_recursion = 1; | |
db2c4c77 | 3222 | trace_lock_release(lock, nested, ip); |
fbb9ce95 IM |
3223 | __lock_release(lock, nested, ip); |
3224 | current->lockdep_recursion = 0; | |
3225 | raw_local_irq_restore(flags); | |
3226 | } | |
fbb9ce95 IM |
3227 | EXPORT_SYMBOL_GPL(lock_release); |
3228 | ||
f607c668 PZ |
3229 | int lock_is_held(struct lockdep_map *lock) |
3230 | { | |
3231 | unsigned long flags; | |
3232 | int ret = 0; | |
3233 | ||
3234 | if (unlikely(current->lockdep_recursion)) | |
3235 | return ret; | |
3236 | ||
3237 | raw_local_irq_save(flags); | |
3238 | check_flags(flags); | |
3239 | ||
3240 | current->lockdep_recursion = 1; | |
3241 | ret = __lock_is_held(lock); | |
3242 | current->lockdep_recursion = 0; | |
3243 | raw_local_irq_restore(flags); | |
3244 | ||
3245 | return ret; | |
3246 | } | |
3247 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3248 | ||
cf40bd16 NP |
3249 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3250 | { | |
3251 | current->lockdep_reclaim_gfp = gfp_mask; | |
3252 | } | |
3253 | ||
3254 | void lockdep_clear_current_reclaim_state(void) | |
3255 | { | |
3256 | current->lockdep_reclaim_gfp = 0; | |
3257 | } | |
3258 | ||
f20786ff PZ |
3259 | #ifdef CONFIG_LOCK_STAT |
3260 | static int | |
3261 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3262 | unsigned long ip) | |
3263 | { | |
3264 | if (!debug_locks_off()) | |
3265 | return 0; | |
3266 | if (debug_locks_silent) | |
3267 | return 0; | |
3268 | ||
3269 | printk("\n=================================\n"); | |
3270 | printk( "[ BUG: bad contention detected! ]\n"); | |
3271 | printk( "---------------------------------\n"); | |
3272 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3273 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3274 | print_lockdep_cache(lock); |
3275 | printk(") at:\n"); | |
3276 | print_ip_sym(ip); | |
3277 | printk("but there are no locks held!\n"); | |
3278 | printk("\nother info that might help us debug this:\n"); | |
3279 | lockdep_print_held_locks(curr); | |
3280 | ||
3281 | printk("\nstack backtrace:\n"); | |
3282 | dump_stack(); | |
3283 | ||
3284 | return 0; | |
3285 | } | |
3286 | ||
3287 | static void | |
3288 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3289 | { | |
3290 | struct task_struct *curr = current; | |
3291 | struct held_lock *hlock, *prev_hlock; | |
3292 | struct lock_class_stats *stats; | |
3293 | unsigned int depth; | |
c7e78cff | 3294 | int i, contention_point, contending_point; |
f20786ff PZ |
3295 | |
3296 | depth = curr->lockdep_depth; | |
3297 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3298 | return; | |
3299 | ||
3300 | prev_hlock = NULL; | |
3301 | for (i = depth-1; i >= 0; i--) { | |
3302 | hlock = curr->held_locks + i; | |
3303 | /* | |
3304 | * We must not cross into another context: | |
3305 | */ | |
3306 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3307 | break; | |
bb97a91e | 3308 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3309 | goto found_it; |
3310 | prev_hlock = hlock; | |
3311 | } | |
3312 | print_lock_contention_bug(curr, lock, ip); | |
3313 | return; | |
3314 | ||
3315 | found_it: | |
bb97a91e PZ |
3316 | if (hlock->instance != lock) |
3317 | return; | |
3318 | ||
3365e779 | 3319 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3320 | |
c7e78cff PZ |
3321 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3322 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3323 | lock->ip); | |
f20786ff | 3324 | |
f82b217e | 3325 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3326 | if (contention_point < LOCKSTAT_POINTS) |
3327 | stats->contention_point[contention_point]++; | |
3328 | if (contending_point < LOCKSTAT_POINTS) | |
3329 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3330 | if (lock->cpu != smp_processor_id()) |
3331 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3332 | put_lock_stats(stats); |
3333 | } | |
3334 | ||
3335 | static void | |
c7e78cff | 3336 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3337 | { |
3338 | struct task_struct *curr = current; | |
3339 | struct held_lock *hlock, *prev_hlock; | |
3340 | struct lock_class_stats *stats; | |
3341 | unsigned int depth; | |
3365e779 | 3342 | u64 now, waittime = 0; |
96645678 | 3343 | int i, cpu; |
f20786ff PZ |
3344 | |
3345 | depth = curr->lockdep_depth; | |
3346 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3347 | return; | |
3348 | ||
3349 | prev_hlock = NULL; | |
3350 | for (i = depth-1; i >= 0; i--) { | |
3351 | hlock = curr->held_locks + i; | |
3352 | /* | |
3353 | * We must not cross into another context: | |
3354 | */ | |
3355 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3356 | break; | |
bb97a91e | 3357 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3358 | goto found_it; |
3359 | prev_hlock = hlock; | |
3360 | } | |
3361 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3362 | return; | |
3363 | ||
3364 | found_it: | |
bb97a91e PZ |
3365 | if (hlock->instance != lock) |
3366 | return; | |
3367 | ||
96645678 PZ |
3368 | cpu = smp_processor_id(); |
3369 | if (hlock->waittime_stamp) { | |
3365e779 | 3370 | now = lockstat_clock(); |
96645678 PZ |
3371 | waittime = now - hlock->waittime_stamp; |
3372 | hlock->holdtime_stamp = now; | |
3373 | } | |
f20786ff | 3374 | |
2062501a FW |
3375 | trace_lock_acquired(lock, ip, waittime); |
3376 | ||
f82b217e | 3377 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3378 | if (waittime) { |
3379 | if (hlock->read) | |
3380 | lock_time_inc(&stats->read_waittime, waittime); | |
3381 | else | |
3382 | lock_time_inc(&stats->write_waittime, waittime); | |
3383 | } | |
3384 | if (lock->cpu != cpu) | |
3385 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3386 | put_lock_stats(stats); |
96645678 PZ |
3387 | |
3388 | lock->cpu = cpu; | |
c7e78cff | 3389 | lock->ip = ip; |
f20786ff PZ |
3390 | } |
3391 | ||
3392 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3393 | { | |
3394 | unsigned long flags; | |
3395 | ||
3396 | if (unlikely(!lock_stat)) | |
3397 | return; | |
3398 | ||
3399 | if (unlikely(current->lockdep_recursion)) | |
3400 | return; | |
3401 | ||
3402 | raw_local_irq_save(flags); | |
3403 | check_flags(flags); | |
3404 | current->lockdep_recursion = 1; | |
db2c4c77 | 3405 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3406 | __lock_contended(lock, ip); |
3407 | current->lockdep_recursion = 0; | |
3408 | raw_local_irq_restore(flags); | |
3409 | } | |
3410 | EXPORT_SYMBOL_GPL(lock_contended); | |
3411 | ||
c7e78cff | 3412 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3413 | { |
3414 | unsigned long flags; | |
3415 | ||
3416 | if (unlikely(!lock_stat)) | |
3417 | return; | |
3418 | ||
3419 | if (unlikely(current->lockdep_recursion)) | |
3420 | return; | |
3421 | ||
3422 | raw_local_irq_save(flags); | |
3423 | check_flags(flags); | |
3424 | current->lockdep_recursion = 1; | |
c7e78cff | 3425 | __lock_acquired(lock, ip); |
f20786ff PZ |
3426 | current->lockdep_recursion = 0; |
3427 | raw_local_irq_restore(flags); | |
3428 | } | |
3429 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3430 | #endif | |
3431 | ||
fbb9ce95 IM |
3432 | /* |
3433 | * Used by the testsuite, sanitize the validator state | |
3434 | * after a simulated failure: | |
3435 | */ | |
3436 | ||
3437 | void lockdep_reset(void) | |
3438 | { | |
3439 | unsigned long flags; | |
23d95a03 | 3440 | int i; |
fbb9ce95 IM |
3441 | |
3442 | raw_local_irq_save(flags); | |
3443 | current->curr_chain_key = 0; | |
3444 | current->lockdep_depth = 0; | |
3445 | current->lockdep_recursion = 0; | |
3446 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3447 | nr_hardirq_chains = 0; | |
3448 | nr_softirq_chains = 0; | |
3449 | nr_process_chains = 0; | |
3450 | debug_locks = 1; | |
23d95a03 IM |
3451 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3452 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3453 | raw_local_irq_restore(flags); |
3454 | } | |
3455 | ||
3456 | static void zap_class(struct lock_class *class) | |
3457 | { | |
3458 | int i; | |
3459 | ||
3460 | /* | |
3461 | * Remove all dependencies this lock is | |
3462 | * involved in: | |
3463 | */ | |
3464 | for (i = 0; i < nr_list_entries; i++) { | |
3465 | if (list_entries[i].class == class) | |
3466 | list_del_rcu(&list_entries[i].entry); | |
3467 | } | |
3468 | /* | |
3469 | * Unhash the class and remove it from the all_lock_classes list: | |
3470 | */ | |
3471 | list_del_rcu(&class->hash_entry); | |
3472 | list_del_rcu(&class->lock_entry); | |
3473 | ||
8bfe0298 | 3474 | class->key = NULL; |
fbb9ce95 IM |
3475 | } |
3476 | ||
fabe874a | 3477 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3478 | { |
3479 | return addr >= start && addr < start + size; | |
3480 | } | |
3481 | ||
3482 | void lockdep_free_key_range(void *start, unsigned long size) | |
3483 | { | |
3484 | struct lock_class *class, *next; | |
3485 | struct list_head *head; | |
3486 | unsigned long flags; | |
3487 | int i; | |
5a26db5b | 3488 | int locked; |
fbb9ce95 IM |
3489 | |
3490 | raw_local_irq_save(flags); | |
5a26db5b | 3491 | locked = graph_lock(); |
fbb9ce95 IM |
3492 | |
3493 | /* | |
3494 | * Unhash all classes that were created by this module: | |
3495 | */ | |
3496 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3497 | head = classhash_table + i; | |
3498 | if (list_empty(head)) | |
3499 | continue; | |
fabe874a | 3500 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3501 | if (within(class->key, start, size)) |
3502 | zap_class(class); | |
fabe874a AV |
3503 | else if (within(class->name, start, size)) |
3504 | zap_class(class); | |
3505 | } | |
fbb9ce95 IM |
3506 | } |
3507 | ||
5a26db5b NP |
3508 | if (locked) |
3509 | graph_unlock(); | |
fbb9ce95 IM |
3510 | raw_local_irq_restore(flags); |
3511 | } | |
3512 | ||
3513 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3514 | { | |
d6d897ce | 3515 | struct lock_class *class, *next; |
fbb9ce95 IM |
3516 | struct list_head *head; |
3517 | unsigned long flags; | |
3518 | int i, j; | |
5a26db5b | 3519 | int locked; |
fbb9ce95 IM |
3520 | |
3521 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3522 | |
3523 | /* | |
d6d897ce IM |
3524 | * Remove all classes this lock might have: |
3525 | */ | |
3526 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3527 | /* | |
3528 | * If the class exists we look it up and zap it: | |
3529 | */ | |
3530 | class = look_up_lock_class(lock, j); | |
3531 | if (class) | |
3532 | zap_class(class); | |
3533 | } | |
3534 | /* | |
3535 | * Debug check: in the end all mapped classes should | |
3536 | * be gone. | |
fbb9ce95 | 3537 | */ |
5a26db5b | 3538 | locked = graph_lock(); |
fbb9ce95 IM |
3539 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3540 | head = classhash_table + i; | |
3541 | if (list_empty(head)) | |
3542 | continue; | |
3543 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3544 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3545 | if (debug_locks_off_graph_unlock()) |
3546 | WARN_ON(1); | |
d6d897ce | 3547 | goto out_restore; |
fbb9ce95 IM |
3548 | } |
3549 | } | |
3550 | } | |
5a26db5b NP |
3551 | if (locked) |
3552 | graph_unlock(); | |
d6d897ce IM |
3553 | |
3554 | out_restore: | |
fbb9ce95 IM |
3555 | raw_local_irq_restore(flags); |
3556 | } | |
3557 | ||
1499993c | 3558 | void lockdep_init(void) |
fbb9ce95 IM |
3559 | { |
3560 | int i; | |
3561 | ||
3562 | /* | |
3563 | * Some architectures have their own start_kernel() | |
3564 | * code which calls lockdep_init(), while we also | |
3565 | * call lockdep_init() from the start_kernel() itself, | |
3566 | * and we want to initialize the hashes only once: | |
3567 | */ | |
3568 | if (lockdep_initialized) | |
3569 | return; | |
3570 | ||
3571 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3572 | INIT_LIST_HEAD(classhash_table + i); | |
3573 | ||
3574 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3575 | INIT_LIST_HEAD(chainhash_table + i); | |
3576 | ||
3577 | lockdep_initialized = 1; | |
3578 | } | |
3579 | ||
3580 | void __init lockdep_info(void) | |
3581 | { | |
3582 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3583 | ||
b0788caf | 3584 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3585 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3586 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3587 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3588 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3589 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3590 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3591 | ||
3592 | printk(" memory used by lock dependency info: %lu kB\n", | |
3593 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3594 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3595 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3596 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 3597 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 3598 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 3599 | + sizeof(struct circular_queue) |
4dd861d6 | 3600 | #endif |
90629209 | 3601 | ) / 1024 |
4dd861d6 | 3602 | ); |
fbb9ce95 IM |
3603 | |
3604 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3605 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3606 | ||
3607 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3608 | if (lockdep_init_error) { |
3609 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3610 | printk("Call stack leading to lockdep invocation was:\n"); | |
3611 | print_stack_trace(&lockdep_init_trace, 0); | |
3612 | } | |
fbb9ce95 IM |
3613 | #endif |
3614 | } | |
3615 | ||
fbb9ce95 IM |
3616 | static void |
3617 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3618 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3619 | { |
3620 | if (!debug_locks_off()) | |
3621 | return; | |
3622 | if (debug_locks_silent) | |
3623 | return; | |
3624 | ||
3625 | printk("\n=========================\n"); | |
3626 | printk( "[ BUG: held lock freed! ]\n"); | |
3627 | printk( "-------------------------\n"); | |
3628 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3629 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3630 | print_lock(hlock); |
fbb9ce95 IM |
3631 | lockdep_print_held_locks(curr); |
3632 | ||
3633 | printk("\nstack backtrace:\n"); | |
3634 | dump_stack(); | |
3635 | } | |
3636 | ||
54561783 ON |
3637 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3638 | const void* lock_from, unsigned long lock_len) | |
3639 | { | |
3640 | return lock_from + lock_len <= mem_from || | |
3641 | mem_from + mem_len <= lock_from; | |
3642 | } | |
3643 | ||
fbb9ce95 IM |
3644 | /* |
3645 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3646 | * is destroyed or reinitialized - this code checks whether there is | |
3647 | * any held lock in the memory range of <from> to <to>: | |
3648 | */ | |
3649 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3650 | { | |
fbb9ce95 IM |
3651 | struct task_struct *curr = current; |
3652 | struct held_lock *hlock; | |
3653 | unsigned long flags; | |
3654 | int i; | |
3655 | ||
3656 | if (unlikely(!debug_locks)) | |
3657 | return; | |
3658 | ||
3659 | local_irq_save(flags); | |
3660 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3661 | hlock = curr->held_locks + i; | |
3662 | ||
54561783 ON |
3663 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3664 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3665 | continue; |
3666 | ||
54561783 | 3667 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3668 | break; |
3669 | } | |
3670 | local_irq_restore(flags); | |
3671 | } | |
ed07536e | 3672 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3673 | |
3674 | static void print_held_locks_bug(struct task_struct *curr) | |
3675 | { | |
3676 | if (!debug_locks_off()) | |
3677 | return; | |
3678 | if (debug_locks_silent) | |
3679 | return; | |
3680 | ||
3681 | printk("\n=====================================\n"); | |
3682 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3683 | printk( "-------------------------------------\n"); | |
3684 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3685 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3686 | lockdep_print_held_locks(curr); |
3687 | ||
3688 | printk("\nstack backtrace:\n"); | |
3689 | dump_stack(); | |
3690 | } | |
3691 | ||
3692 | void debug_check_no_locks_held(struct task_struct *task) | |
3693 | { | |
3694 | if (unlikely(task->lockdep_depth > 0)) | |
3695 | print_held_locks_bug(task); | |
3696 | } | |
3697 | ||
3698 | void debug_show_all_locks(void) | |
3699 | { | |
3700 | struct task_struct *g, *p; | |
3701 | int count = 10; | |
3702 | int unlock = 1; | |
3703 | ||
9c35dd7f JP |
3704 | if (unlikely(!debug_locks)) { |
3705 | printk("INFO: lockdep is turned off.\n"); | |
3706 | return; | |
3707 | } | |
fbb9ce95 IM |
3708 | printk("\nShowing all locks held in the system:\n"); |
3709 | ||
3710 | /* | |
3711 | * Here we try to get the tasklist_lock as hard as possible, | |
3712 | * if not successful after 2 seconds we ignore it (but keep | |
3713 | * trying). This is to enable a debug printout even if a | |
3714 | * tasklist_lock-holding task deadlocks or crashes. | |
3715 | */ | |
3716 | retry: | |
3717 | if (!read_trylock(&tasklist_lock)) { | |
3718 | if (count == 10) | |
3719 | printk("hm, tasklist_lock locked, retrying... "); | |
3720 | if (count) { | |
3721 | count--; | |
3722 | printk(" #%d", 10-count); | |
3723 | mdelay(200); | |
3724 | goto retry; | |
3725 | } | |
3726 | printk(" ignoring it.\n"); | |
3727 | unlock = 0; | |
46fec7ac | 3728 | } else { |
3729 | if (count != 10) | |
3730 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3731 | } |
fbb9ce95 IM |
3732 | |
3733 | do_each_thread(g, p) { | |
85684873 IM |
3734 | /* |
3735 | * It's not reliable to print a task's held locks | |
3736 | * if it's not sleeping (or if it's not the current | |
3737 | * task): | |
3738 | */ | |
3739 | if (p->state == TASK_RUNNING && p != current) | |
3740 | continue; | |
fbb9ce95 IM |
3741 | if (p->lockdep_depth) |
3742 | lockdep_print_held_locks(p); | |
3743 | if (!unlock) | |
3744 | if (read_trylock(&tasklist_lock)) | |
3745 | unlock = 1; | |
3746 | } while_each_thread(g, p); | |
3747 | ||
3748 | printk("\n"); | |
3749 | printk("=============================================\n\n"); | |
3750 | ||
3751 | if (unlock) | |
3752 | read_unlock(&tasklist_lock); | |
3753 | } | |
fbb9ce95 IM |
3754 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3755 | ||
82a1fcb9 IM |
3756 | /* |
3757 | * Careful: only use this function if you are sure that | |
3758 | * the task cannot run in parallel! | |
3759 | */ | |
3760 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3761 | { |
9c35dd7f JP |
3762 | if (unlikely(!debug_locks)) { |
3763 | printk("INFO: lockdep is turned off.\n"); | |
3764 | return; | |
3765 | } | |
fbb9ce95 IM |
3766 | lockdep_print_held_locks(task); |
3767 | } | |
82a1fcb9 IM |
3768 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3769 | ||
3770 | void debug_show_held_locks(struct task_struct *task) | |
3771 | { | |
3772 | __debug_show_held_locks(task); | |
3773 | } | |
fbb9ce95 | 3774 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3775 | |
3776 | void lockdep_sys_exit(void) | |
3777 | { | |
3778 | struct task_struct *curr = current; | |
3779 | ||
3780 | if (unlikely(curr->lockdep_depth)) { | |
3781 | if (!debug_locks_off()) | |
3782 | return; | |
3783 | printk("\n================================================\n"); | |
3784 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3785 | printk( "------------------------------------------------\n"); | |
3786 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3787 | curr->comm, curr->pid); | |
3788 | lockdep_print_held_locks(curr); | |
3789 | } | |
3790 | } | |
0632eb3d PM |
3791 | |
3792 | void lockdep_rcu_dereference(const char *file, const int line) | |
3793 | { | |
3794 | struct task_struct *curr = current; | |
3795 | ||
3796 | if (!debug_locks_off()) | |
3797 | return; | |
056ba4a9 PM |
3798 | printk("\n===================================================\n"); |
3799 | printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n"); | |
3800 | printk( "---------------------------------------------------\n"); | |
0632eb3d PM |
3801 | printk("%s:%d invoked rcu_dereference_check() without protection!\n", |
3802 | file, line); | |
3803 | printk("\nother info that might help us debug this:\n\n"); | |
cc5b83a9 | 3804 | printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks); |
0632eb3d PM |
3805 | lockdep_print_held_locks(curr); |
3806 | printk("\nstack backtrace:\n"); | |
3807 | dump_stack(); | |
3808 | } | |
3809 | EXPORT_SYMBOL_GPL(lockdep_rcu_dereference); |