Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
af012961 | 47 | |
fbb9ce95 IM |
48 | #include <asm/sections.h> |
49 | ||
50 | #include "lockdep_internals.h" | |
51 | ||
a8d154b0 | 52 | #define CREATE_TRACE_POINTS |
67178767 | 53 | #include <trace/events/lock.h> |
a8d154b0 | 54 | |
f20786ff PZ |
55 | #ifdef CONFIG_PROVE_LOCKING |
56 | int prove_locking = 1; | |
57 | module_param(prove_locking, int, 0644); | |
58 | #else | |
59 | #define prove_locking 0 | |
60 | #endif | |
61 | ||
62 | #ifdef CONFIG_LOCK_STAT | |
63 | int lock_stat = 1; | |
64 | module_param(lock_stat, int, 0644); | |
65 | #else | |
66 | #define lock_stat 0 | |
67 | #endif | |
68 | ||
fbb9ce95 | 69 | /* |
74c383f1 IM |
70 | * lockdep_lock: protects the lockdep graph, the hashes and the |
71 | * class/list/hash allocators. | |
fbb9ce95 IM |
72 | * |
73 | * This is one of the rare exceptions where it's justified | |
74 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 75 | * code to recurse back into the lockdep code... |
fbb9ce95 | 76 | */ |
edc35bd7 | 77 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
74c383f1 IM |
78 | |
79 | static int graph_lock(void) | |
80 | { | |
0199c4e6 | 81 | arch_spin_lock(&lockdep_lock); |
74c383f1 IM |
82 | /* |
83 | * Make sure that if another CPU detected a bug while | |
84 | * walking the graph we dont change it (while the other | |
85 | * CPU is busy printing out stuff with the graph lock | |
86 | * dropped already) | |
87 | */ | |
88 | if (!debug_locks) { | |
0199c4e6 | 89 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
90 | return 0; |
91 | } | |
bb065afb SR |
92 | /* prevent any recursions within lockdep from causing deadlocks */ |
93 | current->lockdep_recursion++; | |
74c383f1 IM |
94 | return 1; |
95 | } | |
96 | ||
97 | static inline int graph_unlock(void) | |
98 | { | |
0199c4e6 | 99 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) |
381a2292 JP |
100 | return DEBUG_LOCKS_WARN_ON(1); |
101 | ||
bb065afb | 102 | current->lockdep_recursion--; |
0199c4e6 | 103 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
104 | return 0; |
105 | } | |
106 | ||
107 | /* | |
108 | * Turn lock debugging off and return with 0 if it was off already, | |
109 | * and also release the graph lock: | |
110 | */ | |
111 | static inline int debug_locks_off_graph_unlock(void) | |
112 | { | |
113 | int ret = debug_locks_off(); | |
114 | ||
0199c4e6 | 115 | arch_spin_unlock(&lockdep_lock); |
74c383f1 IM |
116 | |
117 | return ret; | |
118 | } | |
fbb9ce95 IM |
119 | |
120 | static int lockdep_initialized; | |
121 | ||
122 | unsigned long nr_list_entries; | |
af012961 | 123 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 124 | |
fbb9ce95 IM |
125 | /* |
126 | * All data structures here are protected by the global debug_lock. | |
127 | * | |
128 | * Mutex key structs only get allocated, once during bootup, and never | |
129 | * get freed - this significantly simplifies the debugging code. | |
130 | */ | |
131 | unsigned long nr_lock_classes; | |
132 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
133 | ||
f82b217e DJ |
134 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
135 | { | |
136 | if (!hlock->class_idx) { | |
137 | DEBUG_LOCKS_WARN_ON(1); | |
138 | return NULL; | |
139 | } | |
140 | return lock_classes + hlock->class_idx - 1; | |
141 | } | |
142 | ||
f20786ff | 143 | #ifdef CONFIG_LOCK_STAT |
1871e52c TH |
144 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
145 | cpu_lock_stats); | |
f20786ff | 146 | |
3365e779 PZ |
147 | static inline u64 lockstat_clock(void) |
148 | { | |
c676329a | 149 | return local_clock(); |
3365e779 PZ |
150 | } |
151 | ||
c7e78cff | 152 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
153 | { |
154 | int i; | |
155 | ||
c7e78cff PZ |
156 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
157 | if (points[i] == 0) { | |
158 | points[i] = ip; | |
f20786ff PZ |
159 | break; |
160 | } | |
c7e78cff | 161 | if (points[i] == ip) |
f20786ff PZ |
162 | break; |
163 | } | |
164 | ||
165 | return i; | |
166 | } | |
167 | ||
3365e779 | 168 | static void lock_time_inc(struct lock_time *lt, u64 time) |
f20786ff PZ |
169 | { |
170 | if (time > lt->max) | |
171 | lt->max = time; | |
172 | ||
109d71c6 | 173 | if (time < lt->min || !lt->nr) |
f20786ff PZ |
174 | lt->min = time; |
175 | ||
176 | lt->total += time; | |
177 | lt->nr++; | |
178 | } | |
179 | ||
c46261de PZ |
180 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
181 | { | |
109d71c6 FR |
182 | if (!src->nr) |
183 | return; | |
184 | ||
185 | if (src->max > dst->max) | |
186 | dst->max = src->max; | |
187 | ||
188 | if (src->min < dst->min || !dst->nr) | |
189 | dst->min = src->min; | |
190 | ||
c46261de PZ |
191 | dst->total += src->total; |
192 | dst->nr += src->nr; | |
193 | } | |
194 | ||
195 | struct lock_class_stats lock_stats(struct lock_class *class) | |
196 | { | |
197 | struct lock_class_stats stats; | |
198 | int cpu, i; | |
199 | ||
200 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
201 | for_each_possible_cpu(cpu) { | |
202 | struct lock_class_stats *pcs = | |
1871e52c | 203 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
204 | |
205 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
206 | stats.contention_point[i] += pcs->contention_point[i]; | |
207 | ||
c7e78cff PZ |
208 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
209 | stats.contending_point[i] += pcs->contending_point[i]; | |
210 | ||
c46261de PZ |
211 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
212 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
213 | ||
214 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
215 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
216 | |
217 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
218 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
219 | } |
220 | ||
221 | return stats; | |
222 | } | |
223 | ||
224 | void clear_lock_stats(struct lock_class *class) | |
225 | { | |
226 | int cpu; | |
227 | ||
228 | for_each_possible_cpu(cpu) { | |
229 | struct lock_class_stats *cpu_stats = | |
1871e52c | 230 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
c46261de PZ |
231 | |
232 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
233 | } | |
234 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 235 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
236 | } |
237 | ||
f20786ff PZ |
238 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
239 | { | |
1871e52c | 240 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
f20786ff PZ |
241 | } |
242 | ||
243 | static void put_lock_stats(struct lock_class_stats *stats) | |
244 | { | |
1871e52c | 245 | put_cpu_var(cpu_lock_stats); |
f20786ff PZ |
246 | } |
247 | ||
248 | static void lock_release_holdtime(struct held_lock *hlock) | |
249 | { | |
250 | struct lock_class_stats *stats; | |
3365e779 | 251 | u64 holdtime; |
f20786ff PZ |
252 | |
253 | if (!lock_stat) | |
254 | return; | |
255 | ||
3365e779 | 256 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
f20786ff | 257 | |
f82b217e | 258 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
259 | if (hlock->read) |
260 | lock_time_inc(&stats->read_holdtime, holdtime); | |
261 | else | |
262 | lock_time_inc(&stats->write_holdtime, holdtime); | |
263 | put_lock_stats(stats); | |
264 | } | |
265 | #else | |
266 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
267 | { | |
268 | } | |
269 | #endif | |
270 | ||
fbb9ce95 IM |
271 | /* |
272 | * We keep a global list of all lock classes. The list only grows, | |
273 | * never shrinks. The list is only accessed with the lockdep | |
274 | * spinlock lock held. | |
275 | */ | |
276 | LIST_HEAD(all_lock_classes); | |
277 | ||
278 | /* | |
279 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
280 | */ | |
281 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
282 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 283 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
284 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
285 | ||
286 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
287 | ||
fbb9ce95 IM |
288 | /* |
289 | * We put the lock dependency chains into a hash-table as well, to cache | |
290 | * their existence: | |
291 | */ | |
292 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
293 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 294 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
295 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
296 | ||
297 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
298 | ||
299 | /* | |
300 | * The hash key of the lock dependency chains is a hash itself too: | |
301 | * it's a hash of all locks taken up to that lock, including that lock. | |
302 | * It's a 64-bit hash, because it's important for the keys to be | |
303 | * unique. | |
304 | */ | |
305 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
306 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
307 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
308 | (key2)) |
309 | ||
1d09daa5 | 310 | void lockdep_off(void) |
fbb9ce95 IM |
311 | { |
312 | current->lockdep_recursion++; | |
313 | } | |
fbb9ce95 IM |
314 | EXPORT_SYMBOL(lockdep_off); |
315 | ||
1d09daa5 | 316 | void lockdep_on(void) |
fbb9ce95 IM |
317 | { |
318 | current->lockdep_recursion--; | |
319 | } | |
fbb9ce95 IM |
320 | EXPORT_SYMBOL(lockdep_on); |
321 | ||
fbb9ce95 IM |
322 | /* |
323 | * Debugging switches: | |
324 | */ | |
325 | ||
326 | #define VERBOSE 0 | |
33e94e96 | 327 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
328 | |
329 | #if VERBOSE | |
330 | # define HARDIRQ_VERBOSE 1 | |
331 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 332 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
333 | #else |
334 | # define HARDIRQ_VERBOSE 0 | |
335 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 336 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
337 | #endif |
338 | ||
cf40bd16 | 339 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
340 | /* |
341 | * Quick filtering for interesting events: | |
342 | */ | |
343 | static int class_filter(struct lock_class *class) | |
344 | { | |
f9829cce AK |
345 | #if 0 |
346 | /* Example */ | |
fbb9ce95 | 347 | if (class->name_version == 1 && |
f9829cce | 348 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
349 | return 1; |
350 | if (class->name_version == 1 && | |
f9829cce | 351 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 352 | return 1; |
f9829cce | 353 | #endif |
a6640897 IM |
354 | /* Filter everything else. 1 would be to allow everything else */ |
355 | return 0; | |
fbb9ce95 IM |
356 | } |
357 | #endif | |
358 | ||
359 | static int verbose(struct lock_class *class) | |
360 | { | |
361 | #if VERBOSE | |
362 | return class_filter(class); | |
363 | #endif | |
364 | return 0; | |
365 | } | |
366 | ||
fbb9ce95 IM |
367 | /* |
368 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 369 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
370 | */ |
371 | unsigned long nr_stack_trace_entries; | |
372 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
373 | ||
374 | static int save_trace(struct stack_trace *trace) | |
375 | { | |
376 | trace->nr_entries = 0; | |
377 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
378 | trace->entries = stack_trace + nr_stack_trace_entries; | |
379 | ||
5a1b3999 | 380 | trace->skip = 3; |
5a1b3999 | 381 | |
ab1b6f03 | 382 | save_stack_trace(trace); |
fbb9ce95 | 383 | |
4f84f433 PZ |
384 | /* |
385 | * Some daft arches put -1 at the end to indicate its a full trace. | |
386 | * | |
387 | * <rant> this is buggy anyway, since it takes a whole extra entry so a | |
388 | * complete trace that maxes out the entries provided will be reported | |
389 | * as incomplete, friggin useless </rant> | |
390 | */ | |
ea5b41f9 LT |
391 | if (trace->nr_entries != 0 && |
392 | trace->entries[trace->nr_entries-1] == ULONG_MAX) | |
4f84f433 PZ |
393 | trace->nr_entries--; |
394 | ||
fbb9ce95 IM |
395 | trace->max_entries = trace->nr_entries; |
396 | ||
397 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 | 398 | |
4f84f433 | 399 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
74c383f1 IM |
400 | if (!debug_locks_off_graph_unlock()) |
401 | return 0; | |
402 | ||
403 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
404 | printk("turning off the locking correctness validator.\n"); | |
405 | dump_stack(); | |
406 | ||
fbb9ce95 IM |
407 | return 0; |
408 | } | |
409 | ||
410 | return 1; | |
411 | } | |
412 | ||
413 | unsigned int nr_hardirq_chains; | |
414 | unsigned int nr_softirq_chains; | |
415 | unsigned int nr_process_chains; | |
416 | unsigned int max_lockdep_depth; | |
fbb9ce95 IM |
417 | |
418 | #ifdef CONFIG_DEBUG_LOCKDEP | |
419 | /* | |
420 | * We cannot printk in early bootup code. Not even early_printk() | |
421 | * might work. So we mark any initialization errors and printk | |
422 | * about it later on, in lockdep_info(). | |
423 | */ | |
424 | static int lockdep_init_error; | |
c71063c9 JB |
425 | static unsigned long lockdep_init_trace_data[20]; |
426 | static struct stack_trace lockdep_init_trace = { | |
427 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
428 | .entries = lockdep_init_trace_data, | |
429 | }; | |
fbb9ce95 IM |
430 | |
431 | /* | |
432 | * Various lockdep statistics: | |
433 | */ | |
bd6d29c2 | 434 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
fbb9ce95 IM |
435 | #endif |
436 | ||
437 | /* | |
438 | * Locking printouts: | |
439 | */ | |
440 | ||
fabe9c42 | 441 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
442 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
443 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
444 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
445 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 446 | |
fbb9ce95 IM |
447 | static const char *usage_str[] = |
448 | { | |
fabe9c42 PZ |
449 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
450 | #include "lockdep_states.h" | |
451 | #undef LOCKDEP_STATE | |
452 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
453 | }; |
454 | ||
455 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
456 | { | |
ffb45122 | 457 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
458 | } |
459 | ||
3ff176ca | 460 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 461 | { |
3ff176ca PZ |
462 | return 1UL << bit; |
463 | } | |
fbb9ce95 | 464 | |
3ff176ca PZ |
465 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
466 | { | |
467 | char c = '.'; | |
468 | ||
469 | if (class->usage_mask & lock_flag(bit + 2)) | |
470 | c = '+'; | |
471 | if (class->usage_mask & lock_flag(bit)) { | |
472 | c = '-'; | |
473 | if (class->usage_mask & lock_flag(bit + 2)) | |
474 | c = '?'; | |
fbb9ce95 IM |
475 | } |
476 | ||
3ff176ca PZ |
477 | return c; |
478 | } | |
cf40bd16 | 479 | |
f510b233 | 480 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 481 | { |
f510b233 | 482 | int i = 0; |
cf40bd16 | 483 | |
f510b233 PZ |
484 | #define LOCKDEP_STATE(__STATE) \ |
485 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
486 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
487 | #include "lockdep_states.h" | |
488 | #undef LOCKDEP_STATE | |
489 | ||
490 | usage[i] = '\0'; | |
fbb9ce95 IM |
491 | } |
492 | ||
3003eba3 SR |
493 | static int __print_lock_name(struct lock_class *class) |
494 | { | |
495 | char str[KSYM_NAME_LEN]; | |
496 | const char *name; | |
497 | ||
498 | name = class->name; | |
499 | if (!name) | |
500 | name = __get_key_name(class->key, str); | |
501 | ||
502 | return printk("%s", name); | |
503 | } | |
504 | ||
fbb9ce95 IM |
505 | static void print_lock_name(struct lock_class *class) |
506 | { | |
f510b233 | 507 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
508 | const char *name; |
509 | ||
f510b233 | 510 | get_usage_chars(class, usage); |
fbb9ce95 IM |
511 | |
512 | name = class->name; | |
513 | if (!name) { | |
514 | name = __get_key_name(class->key, str); | |
515 | printk(" (%s", name); | |
516 | } else { | |
517 | printk(" (%s", name); | |
518 | if (class->name_version > 1) | |
519 | printk("#%d", class->name_version); | |
520 | if (class->subclass) | |
521 | printk("/%d", class->subclass); | |
522 | } | |
f510b233 | 523 | printk("){%s}", usage); |
fbb9ce95 IM |
524 | } |
525 | ||
526 | static void print_lockdep_cache(struct lockdep_map *lock) | |
527 | { | |
528 | const char *name; | |
9281acea | 529 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
530 | |
531 | name = lock->name; | |
532 | if (!name) | |
533 | name = __get_key_name(lock->key->subkeys, str); | |
534 | ||
535 | printk("%s", name); | |
536 | } | |
537 | ||
538 | static void print_lock(struct held_lock *hlock) | |
539 | { | |
f82b217e | 540 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
541 | printk(", at: "); |
542 | print_ip_sym(hlock->acquire_ip); | |
543 | } | |
544 | ||
545 | static void lockdep_print_held_locks(struct task_struct *curr) | |
546 | { | |
547 | int i, depth = curr->lockdep_depth; | |
548 | ||
549 | if (!depth) { | |
ba25f9dc | 550 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
551 | return; |
552 | } | |
553 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 554 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
555 | |
556 | for (i = 0; i < depth; i++) { | |
557 | printk(" #%d: ", i); | |
558 | print_lock(curr->held_locks + i); | |
559 | } | |
560 | } | |
fbb9ce95 | 561 | |
8e18257d PZ |
562 | static void print_kernel_version(void) |
563 | { | |
564 | printk("%s %.*s\n", init_utsname()->release, | |
565 | (int)strcspn(init_utsname()->version, " "), | |
566 | init_utsname()->version); | |
567 | } | |
568 | ||
569 | static int very_verbose(struct lock_class *class) | |
570 | { | |
571 | #if VERY_VERBOSE | |
572 | return class_filter(class); | |
573 | #endif | |
574 | return 0; | |
575 | } | |
576 | ||
fbb9ce95 | 577 | /* |
8e18257d | 578 | * Is this the address of a static object: |
fbb9ce95 | 579 | */ |
8e18257d | 580 | static int static_obj(void *obj) |
fbb9ce95 | 581 | { |
8e18257d PZ |
582 | unsigned long start = (unsigned long) &_stext, |
583 | end = (unsigned long) &_end, | |
584 | addr = (unsigned long) obj; | |
8e18257d | 585 | |
fbb9ce95 | 586 | /* |
8e18257d | 587 | * static variable? |
fbb9ce95 | 588 | */ |
8e18257d PZ |
589 | if ((addr >= start) && (addr < end)) |
590 | return 1; | |
fbb9ce95 | 591 | |
2a9ad18d MF |
592 | if (arch_is_kernel_data(addr)) |
593 | return 1; | |
594 | ||
fbb9ce95 | 595 | /* |
10fad5e4 | 596 | * in-kernel percpu var? |
fbb9ce95 | 597 | */ |
10fad5e4 TH |
598 | if (is_kernel_percpu_address(addr)) |
599 | return 1; | |
fbb9ce95 | 600 | |
8e18257d | 601 | /* |
10fad5e4 | 602 | * module static or percpu var? |
8e18257d | 603 | */ |
10fad5e4 | 604 | return is_module_address(addr) || is_module_percpu_address(addr); |
99de055a DJ |
605 | } |
606 | ||
fbb9ce95 | 607 | /* |
8e18257d PZ |
608 | * To make lock name printouts unique, we calculate a unique |
609 | * class->name_version generation counter: | |
fbb9ce95 | 610 | */ |
8e18257d | 611 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 612 | { |
8e18257d PZ |
613 | struct lock_class *class; |
614 | int count = 0; | |
fbb9ce95 | 615 | |
8e18257d | 616 | if (!new_class->name) |
fbb9ce95 IM |
617 | return 0; |
618 | ||
8e18257d PZ |
619 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
620 | if (new_class->key - new_class->subclass == class->key) | |
621 | return class->name_version; | |
622 | if (class->name && !strcmp(class->name, new_class->name)) | |
623 | count = max(count, class->name_version); | |
624 | } | |
fbb9ce95 | 625 | |
8e18257d | 626 | return count + 1; |
fbb9ce95 IM |
627 | } |
628 | ||
8e18257d PZ |
629 | /* |
630 | * Register a lock's class in the hash-table, if the class is not present | |
631 | * yet. Otherwise we look it up. We cache the result in the lock object | |
632 | * itself, so actual lookup of the hash should be once per lock object. | |
633 | */ | |
634 | static inline struct lock_class * | |
635 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 636 | { |
8e18257d PZ |
637 | struct lockdep_subclass_key *key; |
638 | struct list_head *hash_head; | |
639 | struct lock_class *class; | |
fbb9ce95 | 640 | |
8e18257d PZ |
641 | #ifdef CONFIG_DEBUG_LOCKDEP |
642 | /* | |
643 | * If the architecture calls into lockdep before initializing | |
644 | * the hashes then we'll warn about it later. (we cannot printk | |
645 | * right now) | |
646 | */ | |
647 | if (unlikely(!lockdep_initialized)) { | |
648 | lockdep_init(); | |
649 | lockdep_init_error = 1; | |
c71063c9 | 650 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
651 | } |
652 | #endif | |
fbb9ce95 | 653 | |
4ba053c0 HM |
654 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
655 | debug_locks_off(); | |
656 | printk(KERN_ERR | |
657 | "BUG: looking up invalid subclass: %u\n", subclass); | |
658 | printk(KERN_ERR | |
659 | "turning off the locking correctness validator.\n"); | |
660 | dump_stack(); | |
661 | return NULL; | |
662 | } | |
663 | ||
8e18257d PZ |
664 | /* |
665 | * Static locks do not have their class-keys yet - for them the key | |
666 | * is the lock object itself: | |
667 | */ | |
668 | if (unlikely(!lock->key)) | |
669 | lock->key = (void *)lock; | |
fbb9ce95 | 670 | |
8e18257d PZ |
671 | /* |
672 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
673 | * lock_class_key variable is passed in through the mutex_init() | |
674 | * (or spin_lock_init()) call - which acts as the key. For static | |
675 | * locks we use the lock object itself as the key. | |
676 | */ | |
4b32d0a4 PZ |
677 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
678 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 679 | |
8e18257d | 680 | key = lock->key->subkeys + subclass; |
ca268c69 | 681 | |
8e18257d | 682 | hash_head = classhashentry(key); |
74c383f1 | 683 | |
8e18257d PZ |
684 | /* |
685 | * We can walk the hash lockfree, because the hash only | |
686 | * grows, and we are careful when adding entries to the end: | |
687 | */ | |
4b32d0a4 PZ |
688 | list_for_each_entry(class, hash_head, hash_entry) { |
689 | if (class->key == key) { | |
690 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 691 | return class; |
4b32d0a4 PZ |
692 | } |
693 | } | |
fbb9ce95 | 694 | |
8e18257d | 695 | return NULL; |
fbb9ce95 IM |
696 | } |
697 | ||
698 | /* | |
8e18257d PZ |
699 | * Register a lock's class in the hash-table, if the class is not present |
700 | * yet. Otherwise we look it up. We cache the result in the lock object | |
701 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 702 | */ |
8e18257d PZ |
703 | static inline struct lock_class * |
704 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 705 | { |
8e18257d PZ |
706 | struct lockdep_subclass_key *key; |
707 | struct list_head *hash_head; | |
708 | struct lock_class *class; | |
709 | unsigned long flags; | |
710 | ||
711 | class = look_up_lock_class(lock, subclass); | |
712 | if (likely(class)) | |
713 | return class; | |
714 | ||
715 | /* | |
716 | * Debug-check: all keys must be persistent! | |
717 | */ | |
718 | if (!static_obj(lock->key)) { | |
719 | debug_locks_off(); | |
720 | printk("INFO: trying to register non-static key.\n"); | |
721 | printk("the code is fine but needs lockdep annotation.\n"); | |
722 | printk("turning off the locking correctness validator.\n"); | |
723 | dump_stack(); | |
724 | ||
725 | return NULL; | |
726 | } | |
727 | ||
728 | key = lock->key->subkeys + subclass; | |
729 | hash_head = classhashentry(key); | |
730 | ||
731 | raw_local_irq_save(flags); | |
732 | if (!graph_lock()) { | |
733 | raw_local_irq_restore(flags); | |
734 | return NULL; | |
735 | } | |
736 | /* | |
737 | * We have to do the hash-walk again, to avoid races | |
738 | * with another CPU: | |
739 | */ | |
740 | list_for_each_entry(class, hash_head, hash_entry) | |
741 | if (class->key == key) | |
742 | goto out_unlock_set; | |
743 | /* | |
744 | * Allocate a new key from the static array, and add it to | |
745 | * the hash: | |
746 | */ | |
747 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
748 | if (!debug_locks_off_graph_unlock()) { | |
749 | raw_local_irq_restore(flags); | |
750 | return NULL; | |
751 | } | |
752 | raw_local_irq_restore(flags); | |
753 | ||
754 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
755 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 756 | dump_stack(); |
8e18257d PZ |
757 | return NULL; |
758 | } | |
759 | class = lock_classes + nr_lock_classes++; | |
bd6d29c2 | 760 | debug_atomic_inc(nr_unused_locks); |
8e18257d PZ |
761 | class->key = key; |
762 | class->name = lock->name; | |
763 | class->subclass = subclass; | |
764 | INIT_LIST_HEAD(&class->lock_entry); | |
765 | INIT_LIST_HEAD(&class->locks_before); | |
766 | INIT_LIST_HEAD(&class->locks_after); | |
767 | class->name_version = count_matching_names(class); | |
768 | /* | |
769 | * We use RCU's safe list-add method to make | |
770 | * parallel walking of the hash-list safe: | |
771 | */ | |
772 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
773 | /* |
774 | * Add it to the global list of classes: | |
775 | */ | |
776 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
777 | |
778 | if (verbose(class)) { | |
779 | graph_unlock(); | |
780 | raw_local_irq_restore(flags); | |
781 | ||
782 | printk("\nnew class %p: %s", class->key, class->name); | |
783 | if (class->name_version > 1) | |
784 | printk("#%d", class->name_version); | |
785 | printk("\n"); | |
786 | dump_stack(); | |
787 | ||
788 | raw_local_irq_save(flags); | |
789 | if (!graph_lock()) { | |
790 | raw_local_irq_restore(flags); | |
791 | return NULL; | |
792 | } | |
793 | } | |
794 | out_unlock_set: | |
795 | graph_unlock(); | |
796 | raw_local_irq_restore(flags); | |
797 | ||
798 | if (!subclass || force) | |
62016250 HM |
799 | lock->class_cache[0] = class; |
800 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) | |
801 | lock->class_cache[subclass] = class; | |
8e18257d PZ |
802 | |
803 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
804 | return NULL; | |
805 | ||
806 | return class; | |
807 | } | |
808 | ||
809 | #ifdef CONFIG_PROVE_LOCKING | |
810 | /* | |
811 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
812 | * with NULL on failure) | |
813 | */ | |
814 | static struct lock_list *alloc_list_entry(void) | |
815 | { | |
816 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
817 | if (!debug_locks_off_graph_unlock()) | |
818 | return NULL; | |
819 | ||
820 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
821 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 822 | dump_stack(); |
8e18257d PZ |
823 | return NULL; |
824 | } | |
825 | return list_entries + nr_list_entries++; | |
826 | } | |
827 | ||
828 | /* | |
829 | * Add a new dependency to the head of the list: | |
830 | */ | |
831 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
4726f2a6 YZ |
832 | struct list_head *head, unsigned long ip, |
833 | int distance, struct stack_trace *trace) | |
8e18257d PZ |
834 | { |
835 | struct lock_list *entry; | |
836 | /* | |
837 | * Lock not present yet - get a new dependency struct and | |
838 | * add it to the list: | |
839 | */ | |
840 | entry = alloc_list_entry(); | |
841 | if (!entry) | |
842 | return 0; | |
843 | ||
74870172 ZY |
844 | entry->class = this; |
845 | entry->distance = distance; | |
4726f2a6 | 846 | entry->trace = *trace; |
8e18257d PZ |
847 | /* |
848 | * Since we never remove from the dependency list, the list can | |
849 | * be walked lockless by other CPUs, it's only allocation | |
850 | * that must be protected by the spinlock. But this also means | |
851 | * we must make new entries visible only once writes to the | |
852 | * entry become visible - hence the RCU op: | |
853 | */ | |
854 | list_add_tail_rcu(&entry->entry, head); | |
855 | ||
856 | return 1; | |
857 | } | |
858 | ||
98c33edd PZ |
859 | /* |
860 | * For good efficiency of modular, we use power of 2 | |
861 | */ | |
af012961 PZ |
862 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
863 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) | |
864 | ||
98c33edd PZ |
865 | /* |
866 | * The circular_queue and helpers is used to implement the | |
af012961 PZ |
867 | * breadth-first search(BFS)algorithem, by which we can build |
868 | * the shortest path from the next lock to be acquired to the | |
869 | * previous held lock if there is a circular between them. | |
98c33edd | 870 | */ |
af012961 PZ |
871 | struct circular_queue { |
872 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; | |
873 | unsigned int front, rear; | |
874 | }; | |
875 | ||
876 | static struct circular_queue lock_cq; | |
af012961 | 877 | |
12f3dfd0 | 878 | unsigned int max_bfs_queue_depth; |
af012961 | 879 | |
e351b660 ML |
880 | static unsigned int lockdep_dependency_gen_id; |
881 | ||
af012961 PZ |
882 | static inline void __cq_init(struct circular_queue *cq) |
883 | { | |
884 | cq->front = cq->rear = 0; | |
e351b660 | 885 | lockdep_dependency_gen_id++; |
af012961 PZ |
886 | } |
887 | ||
888 | static inline int __cq_empty(struct circular_queue *cq) | |
889 | { | |
890 | return (cq->front == cq->rear); | |
891 | } | |
892 | ||
893 | static inline int __cq_full(struct circular_queue *cq) | |
894 | { | |
895 | return ((cq->rear + 1) & CQ_MASK) == cq->front; | |
896 | } | |
897 | ||
898 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) | |
899 | { | |
900 | if (__cq_full(cq)) | |
901 | return -1; | |
902 | ||
903 | cq->element[cq->rear] = elem; | |
904 | cq->rear = (cq->rear + 1) & CQ_MASK; | |
905 | return 0; | |
906 | } | |
907 | ||
908 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) | |
909 | { | |
910 | if (__cq_empty(cq)) | |
911 | return -1; | |
912 | ||
913 | *elem = cq->element[cq->front]; | |
914 | cq->front = (cq->front + 1) & CQ_MASK; | |
915 | return 0; | |
916 | } | |
917 | ||
918 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) | |
919 | { | |
920 | return (cq->rear - cq->front) & CQ_MASK; | |
921 | } | |
922 | ||
923 | static inline void mark_lock_accessed(struct lock_list *lock, | |
924 | struct lock_list *parent) | |
925 | { | |
926 | unsigned long nr; | |
98c33edd | 927 | |
af012961 PZ |
928 | nr = lock - list_entries; |
929 | WARN_ON(nr >= nr_list_entries); | |
930 | lock->parent = parent; | |
e351b660 | 931 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
af012961 PZ |
932 | } |
933 | ||
934 | static inline unsigned long lock_accessed(struct lock_list *lock) | |
935 | { | |
936 | unsigned long nr; | |
98c33edd | 937 | |
af012961 PZ |
938 | nr = lock - list_entries; |
939 | WARN_ON(nr >= nr_list_entries); | |
e351b660 | 940 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
af012961 PZ |
941 | } |
942 | ||
943 | static inline struct lock_list *get_lock_parent(struct lock_list *child) | |
944 | { | |
945 | return child->parent; | |
946 | } | |
947 | ||
948 | static inline int get_lock_depth(struct lock_list *child) | |
949 | { | |
950 | int depth = 0; | |
951 | struct lock_list *parent; | |
952 | ||
953 | while ((parent = get_lock_parent(child))) { | |
954 | child = parent; | |
955 | depth++; | |
956 | } | |
957 | return depth; | |
958 | } | |
959 | ||
9e2d551e | 960 | static int __bfs(struct lock_list *source_entry, |
af012961 PZ |
961 | void *data, |
962 | int (*match)(struct lock_list *entry, void *data), | |
963 | struct lock_list **target_entry, | |
964 | int forward) | |
c94aa5ca ML |
965 | { |
966 | struct lock_list *entry; | |
d588e461 | 967 | struct list_head *head; |
c94aa5ca ML |
968 | struct circular_queue *cq = &lock_cq; |
969 | int ret = 1; | |
970 | ||
9e2d551e | 971 | if (match(source_entry, data)) { |
c94aa5ca ML |
972 | *target_entry = source_entry; |
973 | ret = 0; | |
974 | goto exit; | |
975 | } | |
976 | ||
d588e461 ML |
977 | if (forward) |
978 | head = &source_entry->class->locks_after; | |
979 | else | |
980 | head = &source_entry->class->locks_before; | |
981 | ||
982 | if (list_empty(head)) | |
983 | goto exit; | |
984 | ||
985 | __cq_init(cq); | |
c94aa5ca ML |
986 | __cq_enqueue(cq, (unsigned long)source_entry); |
987 | ||
988 | while (!__cq_empty(cq)) { | |
989 | struct lock_list *lock; | |
c94aa5ca ML |
990 | |
991 | __cq_dequeue(cq, (unsigned long *)&lock); | |
992 | ||
993 | if (!lock->class) { | |
994 | ret = -2; | |
995 | goto exit; | |
996 | } | |
997 | ||
998 | if (forward) | |
999 | head = &lock->class->locks_after; | |
1000 | else | |
1001 | head = &lock->class->locks_before; | |
1002 | ||
1003 | list_for_each_entry(entry, head, entry) { | |
1004 | if (!lock_accessed(entry)) { | |
12f3dfd0 | 1005 | unsigned int cq_depth; |
c94aa5ca | 1006 | mark_lock_accessed(entry, lock); |
9e2d551e | 1007 | if (match(entry, data)) { |
c94aa5ca ML |
1008 | *target_entry = entry; |
1009 | ret = 0; | |
1010 | goto exit; | |
1011 | } | |
1012 | ||
1013 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
1014 | ret = -1; | |
1015 | goto exit; | |
1016 | } | |
12f3dfd0 ML |
1017 | cq_depth = __cq_get_elem_count(cq); |
1018 | if (max_bfs_queue_depth < cq_depth) | |
1019 | max_bfs_queue_depth = cq_depth; | |
c94aa5ca ML |
1020 | } |
1021 | } | |
1022 | } | |
1023 | exit: | |
1024 | return ret; | |
1025 | } | |
1026 | ||
d7aaba14 | 1027 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
1028 | void *data, |
1029 | int (*match)(struct lock_list *entry, void *data), | |
1030 | struct lock_list **target_entry) | |
c94aa5ca | 1031 | { |
9e2d551e | 1032 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1033 | |
1034 | } | |
1035 | ||
d7aaba14 | 1036 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1037 | void *data, |
1038 | int (*match)(struct lock_list *entry, void *data), | |
1039 | struct lock_list **target_entry) | |
c94aa5ca | 1040 | { |
9e2d551e | 1041 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1042 | |
1043 | } | |
1044 | ||
8e18257d PZ |
1045 | /* |
1046 | * Recursive, forwards-direction lock-dependency checking, used for | |
1047 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1048 | * checking. | |
8e18257d | 1049 | */ |
8e18257d PZ |
1050 | |
1051 | /* | |
1052 | * Print a dependency chain entry (this is only done when a deadlock | |
1053 | * has been detected): | |
1054 | */ | |
1055 | static noinline int | |
24208ca7 | 1056 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1057 | { |
1058 | if (debug_locks_silent) | |
1059 | return 0; | |
1060 | printk("\n-> #%u", depth); | |
1061 | print_lock_name(target->class); | |
1062 | printk(":\n"); | |
1063 | print_stack_trace(&target->trace, 6); | |
1064 | ||
1065 | return 0; | |
1066 | } | |
1067 | ||
f4185812 SR |
1068 | static void |
1069 | print_circular_lock_scenario(struct held_lock *src, | |
1070 | struct held_lock *tgt, | |
1071 | struct lock_list *prt) | |
1072 | { | |
1073 | struct lock_class *source = hlock_class(src); | |
1074 | struct lock_class *target = hlock_class(tgt); | |
1075 | struct lock_class *parent = prt->class; | |
1076 | ||
1077 | /* | |
1078 | * A direct locking problem where unsafe_class lock is taken | |
1079 | * directly by safe_class lock, then all we need to show | |
1080 | * is the deadlock scenario, as it is obvious that the | |
1081 | * unsafe lock is taken under the safe lock. | |
1082 | * | |
1083 | * But if there is a chain instead, where the safe lock takes | |
1084 | * an intermediate lock (middle_class) where this lock is | |
1085 | * not the same as the safe lock, then the lock chain is | |
1086 | * used to describe the problem. Otherwise we would need | |
1087 | * to show a different CPU case for each link in the chain | |
1088 | * from the safe_class lock to the unsafe_class lock. | |
1089 | */ | |
1090 | if (parent != source) { | |
1091 | printk("Chain exists of:\n "); | |
1092 | __print_lock_name(source); | |
1093 | printk(" --> "); | |
1094 | __print_lock_name(parent); | |
1095 | printk(" --> "); | |
1096 | __print_lock_name(target); | |
1097 | printk("\n\n"); | |
1098 | } | |
1099 | ||
1100 | printk(" Possible unsafe locking scenario:\n\n"); | |
1101 | printk(" CPU0 CPU1\n"); | |
1102 | printk(" ---- ----\n"); | |
1103 | printk(" lock("); | |
1104 | __print_lock_name(target); | |
1105 | printk(");\n"); | |
1106 | printk(" lock("); | |
1107 | __print_lock_name(parent); | |
1108 | printk(");\n"); | |
1109 | printk(" lock("); | |
1110 | __print_lock_name(target); | |
1111 | printk(");\n"); | |
1112 | printk(" lock("); | |
1113 | __print_lock_name(source); | |
1114 | printk(");\n"); | |
1115 | printk("\n *** DEADLOCK ***\n\n"); | |
1116 | } | |
1117 | ||
8e18257d PZ |
1118 | /* |
1119 | * When a circular dependency is detected, print the | |
1120 | * header first: | |
1121 | */ | |
1122 | static noinline int | |
db0002a3 ML |
1123 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1124 | struct held_lock *check_src, | |
1125 | struct held_lock *check_tgt) | |
8e18257d PZ |
1126 | { |
1127 | struct task_struct *curr = current; | |
1128 | ||
c94aa5ca | 1129 | if (debug_locks_silent) |
8e18257d PZ |
1130 | return 0; |
1131 | ||
1132 | printk("\n=======================================================\n"); | |
1133 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1134 | print_kernel_version(); | |
1135 | printk( "-------------------------------------------------------\n"); | |
1136 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1137 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1138 | print_lock(check_src); |
8e18257d | 1139 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1140 | print_lock(check_tgt); |
8e18257d PZ |
1141 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1142 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1143 | ||
1144 | print_circular_bug_entry(entry, depth); | |
1145 | ||
1146 | return 0; | |
1147 | } | |
1148 | ||
9e2d551e ML |
1149 | static inline int class_equal(struct lock_list *entry, void *data) |
1150 | { | |
1151 | return entry->class == data; | |
1152 | } | |
1153 | ||
db0002a3 ML |
1154 | static noinline int print_circular_bug(struct lock_list *this, |
1155 | struct lock_list *target, | |
1156 | struct held_lock *check_src, | |
1157 | struct held_lock *check_tgt) | |
8e18257d PZ |
1158 | { |
1159 | struct task_struct *curr = current; | |
c94aa5ca | 1160 | struct lock_list *parent; |
f4185812 | 1161 | struct lock_list *first_parent; |
24208ca7 | 1162 | int depth; |
8e18257d | 1163 | |
c94aa5ca | 1164 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1165 | return 0; |
1166 | ||
db0002a3 | 1167 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1168 | return 0; |
1169 | ||
c94aa5ca ML |
1170 | depth = get_lock_depth(target); |
1171 | ||
db0002a3 | 1172 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1173 | |
1174 | parent = get_lock_parent(target); | |
f4185812 | 1175 | first_parent = parent; |
c94aa5ca ML |
1176 | |
1177 | while (parent) { | |
1178 | print_circular_bug_entry(parent, --depth); | |
1179 | parent = get_lock_parent(parent); | |
1180 | } | |
8e18257d PZ |
1181 | |
1182 | printk("\nother info that might help us debug this:\n\n"); | |
f4185812 SR |
1183 | print_circular_lock_scenario(check_src, check_tgt, |
1184 | first_parent); | |
1185 | ||
8e18257d PZ |
1186 | lockdep_print_held_locks(curr); |
1187 | ||
1188 | printk("\nstack backtrace:\n"); | |
1189 | dump_stack(); | |
1190 | ||
1191 | return 0; | |
1192 | } | |
1193 | ||
db0002a3 ML |
1194 | static noinline int print_bfs_bug(int ret) |
1195 | { | |
1196 | if (!debug_locks_off_graph_unlock()) | |
1197 | return 0; | |
1198 | ||
1199 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1200 | ||
1201 | return 0; | |
1202 | } | |
1203 | ||
ef681026 | 1204 | static int noop_count(struct lock_list *entry, void *data) |
419ca3f1 | 1205 | { |
ef681026 ML |
1206 | (*(unsigned long *)data)++; |
1207 | return 0; | |
1208 | } | |
419ca3f1 | 1209 | |
ef681026 ML |
1210 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
1211 | { | |
1212 | unsigned long count = 0; | |
1213 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1214 | |
ef681026 | 1215 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1216 | |
ef681026 | 1217 | return count; |
419ca3f1 | 1218 | } |
419ca3f1 DM |
1219 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
1220 | { | |
1221 | unsigned long ret, flags; | |
ef681026 ML |
1222 | struct lock_list this; |
1223 | ||
1224 | this.parent = NULL; | |
1225 | this.class = class; | |
419ca3f1 DM |
1226 | |
1227 | local_irq_save(flags); | |
0199c4e6 | 1228 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1229 | ret = __lockdep_count_forward_deps(&this); |
0199c4e6 | 1230 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1231 | local_irq_restore(flags); |
1232 | ||
1233 | return ret; | |
1234 | } | |
1235 | ||
ef681026 | 1236 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
419ca3f1 | 1237 | { |
ef681026 ML |
1238 | unsigned long count = 0; |
1239 | struct lock_list *uninitialized_var(target_entry); | |
419ca3f1 | 1240 | |
ef681026 | 1241 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
419ca3f1 | 1242 | |
ef681026 | 1243 | return count; |
419ca3f1 DM |
1244 | } |
1245 | ||
1246 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1247 | { | |
1248 | unsigned long ret, flags; | |
ef681026 ML |
1249 | struct lock_list this; |
1250 | ||
1251 | this.parent = NULL; | |
1252 | this.class = class; | |
419ca3f1 DM |
1253 | |
1254 | local_irq_save(flags); | |
0199c4e6 | 1255 | arch_spin_lock(&lockdep_lock); |
ef681026 | 1256 | ret = __lockdep_count_backward_deps(&this); |
0199c4e6 | 1257 | arch_spin_unlock(&lockdep_lock); |
419ca3f1 DM |
1258 | local_irq_restore(flags); |
1259 | ||
1260 | return ret; | |
1261 | } | |
1262 | ||
8e18257d PZ |
1263 | /* |
1264 | * Prove that the dependency graph starting at <entry> can not | |
1265 | * lead to <target>. Print an error and return 0 if it does. | |
1266 | */ | |
1267 | static noinline int | |
db0002a3 ML |
1268 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1269 | struct lock_list **target_entry) | |
8e18257d | 1270 | { |
db0002a3 | 1271 | int result; |
8e18257d | 1272 | |
bd6d29c2 | 1273 | debug_atomic_inc(nr_cyclic_checks); |
419ca3f1 | 1274 | |
d7aaba14 | 1275 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1276 | |
db0002a3 ML |
1277 | return result; |
1278 | } | |
c94aa5ca | 1279 | |
81d68a96 | 1280 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1281 | /* |
1282 | * Forwards and backwards subgraph searching, for the purposes of | |
1283 | * proving that two subgraphs can be connected by a new dependency | |
1284 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1285 | */ | |
fbb9ce95 | 1286 | |
d7aaba14 ML |
1287 | static inline int usage_match(struct lock_list *entry, void *bit) |
1288 | { | |
1289 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1290 | } | |
1291 | ||
1292 | ||
1293 | ||
fbb9ce95 IM |
1294 | /* |
1295 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1296 | * at @root->class that matches @bit. |
fbb9ce95 | 1297 | * |
d7aaba14 ML |
1298 | * Return 0 if such a node exists in the subgraph, and put that node |
1299 | * into *@target_entry. | |
fbb9ce95 | 1300 | * |
d7aaba14 ML |
1301 | * Return 1 otherwise and keep *@target_entry unchanged. |
1302 | * Return <0 on error. | |
fbb9ce95 | 1303 | */ |
d7aaba14 ML |
1304 | static int |
1305 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1306 | struct lock_list **target_entry) | |
fbb9ce95 | 1307 | { |
d7aaba14 | 1308 | int result; |
fbb9ce95 | 1309 | |
bd6d29c2 | 1310 | debug_atomic_inc(nr_find_usage_forwards_checks); |
fbb9ce95 | 1311 | |
d7aaba14 ML |
1312 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1313 | ||
1314 | return result; | |
fbb9ce95 IM |
1315 | } |
1316 | ||
1317 | /* | |
1318 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1319 | * at @root->class that matches @bit. |
fbb9ce95 | 1320 | * |
d7aaba14 ML |
1321 | * Return 0 if such a node exists in the subgraph, and put that node |
1322 | * into *@target_entry. | |
fbb9ce95 | 1323 | * |
d7aaba14 ML |
1324 | * Return 1 otherwise and keep *@target_entry unchanged. |
1325 | * Return <0 on error. | |
fbb9ce95 | 1326 | */ |
d7aaba14 ML |
1327 | static int |
1328 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1329 | struct lock_list **target_entry) | |
fbb9ce95 | 1330 | { |
d7aaba14 | 1331 | int result; |
fbb9ce95 | 1332 | |
bd6d29c2 | 1333 | debug_atomic_inc(nr_find_usage_backwards_checks); |
fbb9ce95 | 1334 | |
d7aaba14 | 1335 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1336 | |
d7aaba14 | 1337 | return result; |
fbb9ce95 IM |
1338 | } |
1339 | ||
af012961 PZ |
1340 | static void print_lock_class_header(struct lock_class *class, int depth) |
1341 | { | |
1342 | int bit; | |
1343 | ||
1344 | printk("%*s->", depth, ""); | |
1345 | print_lock_name(class); | |
1346 | printk(" ops: %lu", class->ops); | |
1347 | printk(" {\n"); | |
1348 | ||
1349 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
1350 | if (class->usage_mask & (1 << bit)) { | |
1351 | int len = depth; | |
1352 | ||
1353 | len += printk("%*s %s", depth, "", usage_str[bit]); | |
1354 | len += printk(" at:\n"); | |
1355 | print_stack_trace(class->usage_traces + bit, len); | |
1356 | } | |
1357 | } | |
1358 | printk("%*s }\n", depth, ""); | |
1359 | ||
1360 | printk("%*s ... key at: ",depth,""); | |
1361 | print_ip_sym((unsigned long)class->key); | |
1362 | } | |
1363 | ||
1364 | /* | |
1365 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
1366 | */ | |
1367 | static void __used | |
1368 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
1369 | struct lock_list *root) | |
1370 | { | |
1371 | struct lock_list *entry = leaf; | |
1372 | int depth; | |
1373 | ||
1374 | /*compute depth from generated tree by BFS*/ | |
1375 | depth = get_lock_depth(leaf); | |
1376 | ||
1377 | do { | |
1378 | print_lock_class_header(entry->class, depth); | |
1379 | printk("%*s ... acquired at:\n", depth, ""); | |
1380 | print_stack_trace(&entry->trace, 2); | |
1381 | printk("\n"); | |
1382 | ||
1383 | if (depth == 0 && (entry != root)) { | |
6be8c393 | 1384 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
af012961 PZ |
1385 | break; |
1386 | } | |
1387 | ||
1388 | entry = get_lock_parent(entry); | |
1389 | depth--; | |
1390 | } while (entry && (depth >= 0)); | |
1391 | ||
1392 | return; | |
1393 | } | |
d7aaba14 | 1394 | |
3003eba3 SR |
1395 | static void |
1396 | print_irq_lock_scenario(struct lock_list *safe_entry, | |
1397 | struct lock_list *unsafe_entry, | |
dad3d743 SR |
1398 | struct lock_class *prev_class, |
1399 | struct lock_class *next_class) | |
3003eba3 SR |
1400 | { |
1401 | struct lock_class *safe_class = safe_entry->class; | |
1402 | struct lock_class *unsafe_class = unsafe_entry->class; | |
dad3d743 | 1403 | struct lock_class *middle_class = prev_class; |
3003eba3 SR |
1404 | |
1405 | if (middle_class == safe_class) | |
dad3d743 | 1406 | middle_class = next_class; |
3003eba3 SR |
1407 | |
1408 | /* | |
1409 | * A direct locking problem where unsafe_class lock is taken | |
1410 | * directly by safe_class lock, then all we need to show | |
1411 | * is the deadlock scenario, as it is obvious that the | |
1412 | * unsafe lock is taken under the safe lock. | |
1413 | * | |
1414 | * But if there is a chain instead, where the safe lock takes | |
1415 | * an intermediate lock (middle_class) where this lock is | |
1416 | * not the same as the safe lock, then the lock chain is | |
1417 | * used to describe the problem. Otherwise we would need | |
1418 | * to show a different CPU case for each link in the chain | |
1419 | * from the safe_class lock to the unsafe_class lock. | |
1420 | */ | |
1421 | if (middle_class != unsafe_class) { | |
1422 | printk("Chain exists of:\n "); | |
1423 | __print_lock_name(safe_class); | |
1424 | printk(" --> "); | |
1425 | __print_lock_name(middle_class); | |
1426 | printk(" --> "); | |
1427 | __print_lock_name(unsafe_class); | |
1428 | printk("\n\n"); | |
1429 | } | |
1430 | ||
1431 | printk(" Possible interrupt unsafe locking scenario:\n\n"); | |
1432 | printk(" CPU0 CPU1\n"); | |
1433 | printk(" ---- ----\n"); | |
1434 | printk(" lock("); | |
1435 | __print_lock_name(unsafe_class); | |
1436 | printk(");\n"); | |
1437 | printk(" local_irq_disable();\n"); | |
1438 | printk(" lock("); | |
1439 | __print_lock_name(safe_class); | |
1440 | printk(");\n"); | |
1441 | printk(" lock("); | |
1442 | __print_lock_name(middle_class); | |
1443 | printk(");\n"); | |
1444 | printk(" <Interrupt>\n"); | |
1445 | printk(" lock("); | |
1446 | __print_lock_name(safe_class); | |
1447 | printk(");\n"); | |
1448 | printk("\n *** DEADLOCK ***\n\n"); | |
1449 | } | |
1450 | ||
fbb9ce95 IM |
1451 | static int |
1452 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1453 | struct lock_list *prev_root, |
1454 | struct lock_list *next_root, | |
1455 | struct lock_list *backwards_entry, | |
1456 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1457 | struct held_lock *prev, |
1458 | struct held_lock *next, | |
1459 | enum lock_usage_bit bit1, | |
1460 | enum lock_usage_bit bit2, | |
1461 | const char *irqclass) | |
1462 | { | |
74c383f1 | 1463 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1464 | return 0; |
1465 | ||
1466 | printk("\n======================================================\n"); | |
1467 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1468 | irqclass, irqclass); | |
99de055a | 1469 | print_kernel_version(); |
fbb9ce95 IM |
1470 | printk( "------------------------------------------------------\n"); |
1471 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1472 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1473 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1474 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1475 | curr->hardirqs_enabled, | |
1476 | curr->softirqs_enabled); | |
1477 | print_lock(next); | |
1478 | ||
1479 | printk("\nand this task is already holding:\n"); | |
1480 | print_lock(prev); | |
1481 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1482 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1483 | printk(" ->"); |
f82b217e | 1484 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1485 | printk("\n"); |
1486 | ||
1487 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1488 | irqclass); | |
24208ca7 | 1489 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1490 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1491 | ||
24208ca7 | 1492 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1493 | |
1494 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1495 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1496 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1497 | printk("..."); | |
1498 | ||
24208ca7 | 1499 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1500 | |
1501 | printk("\nother info that might help us debug this:\n\n"); | |
dad3d743 SR |
1502 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
1503 | hlock_class(prev), hlock_class(next)); | |
3003eba3 | 1504 | |
fbb9ce95 IM |
1505 | lockdep_print_held_locks(curr); |
1506 | ||
24208ca7 ML |
1507 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1508 | printk(" and the holding lock:\n"); | |
1509 | if (!save_trace(&prev_root->trace)) | |
1510 | return 0; | |
1511 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1512 | |
24208ca7 ML |
1513 | printk("\nthe dependencies between the lock to be acquired"); |
1514 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1515 | if (!save_trace(&next_root->trace)) | |
1516 | return 0; | |
1517 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1518 | |
1519 | printk("\nstack backtrace:\n"); | |
1520 | dump_stack(); | |
1521 | ||
1522 | return 0; | |
1523 | } | |
1524 | ||
1525 | static int | |
1526 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1527 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1528 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1529 | { | |
1530 | int ret; | |
24208ca7 | 1531 | struct lock_list this, that; |
d7aaba14 | 1532 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1533 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1534 | |
1535 | this.parent = NULL; | |
1536 | ||
1537 | this.class = hlock_class(prev); | |
1538 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
af012961 PZ |
1539 | if (ret < 0) |
1540 | return print_bfs_bug(ret); | |
1541 | if (ret == 1) | |
1542 | return ret; | |
d7aaba14 | 1543 | |
24208ca7 ML |
1544 | that.parent = NULL; |
1545 | that.class = hlock_class(next); | |
1546 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
af012961 PZ |
1547 | if (ret < 0) |
1548 | return print_bfs_bug(ret); | |
1549 | if (ret == 1) | |
1550 | return ret; | |
fbb9ce95 | 1551 | |
24208ca7 ML |
1552 | return print_bad_irq_dependency(curr, &this, &that, |
1553 | target_entry, target_entry1, | |
1554 | prev, next, | |
fbb9ce95 IM |
1555 | bit_backwards, bit_forwards, irqclass); |
1556 | } | |
1557 | ||
4f367d8a PZ |
1558 | static const char *state_names[] = { |
1559 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1560 | __stringify(__STATE), |
4f367d8a PZ |
1561 | #include "lockdep_states.h" |
1562 | #undef LOCKDEP_STATE | |
1563 | }; | |
1564 | ||
1565 | static const char *state_rnames[] = { | |
1566 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1567 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1568 | #include "lockdep_states.h" |
1569 | #undef LOCKDEP_STATE | |
1570 | }; | |
1571 | ||
1572 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1573 | { |
4f367d8a PZ |
1574 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1575 | } | |
8e18257d | 1576 | |
4f367d8a PZ |
1577 | static int exclusive_bit(int new_bit) |
1578 | { | |
8e18257d | 1579 | /* |
4f367d8a PZ |
1580 | * USED_IN |
1581 | * USED_IN_READ | |
1582 | * ENABLED | |
1583 | * ENABLED_READ | |
1584 | * | |
1585 | * bit 0 - write/read | |
1586 | * bit 1 - used_in/enabled | |
1587 | * bit 2+ state | |
8e18257d | 1588 | */ |
4f367d8a PZ |
1589 | |
1590 | int state = new_bit & ~3; | |
1591 | int dir = new_bit & 2; | |
8e18257d PZ |
1592 | |
1593 | /* | |
4f367d8a | 1594 | * keep state, bit flip the direction and strip read. |
8e18257d | 1595 | */ |
4f367d8a PZ |
1596 | return state | (dir ^ 2); |
1597 | } | |
1598 | ||
1599 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1600 | struct held_lock *next, enum lock_usage_bit bit) | |
1601 | { | |
8e18257d | 1602 | /* |
4f367d8a PZ |
1603 | * Prove that the new dependency does not connect a hardirq-safe |
1604 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1605 | * the backwards-subgraph starting at <prev>, and the |
1606 | * forwards-subgraph starting at <next>: | |
1607 | */ | |
4f367d8a PZ |
1608 | if (!check_usage(curr, prev, next, bit, |
1609 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1610 | return 0; |
1611 | ||
4f367d8a PZ |
1612 | bit++; /* _READ */ |
1613 | ||
cf40bd16 | 1614 | /* |
4f367d8a PZ |
1615 | * Prove that the new dependency does not connect a hardirq-safe-read |
1616 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1617 | * the backwards-subgraph starting at <prev>, and the |
1618 | * forwards-subgraph starting at <next>: | |
1619 | */ | |
4f367d8a PZ |
1620 | if (!check_usage(curr, prev, next, bit, |
1621 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1622 | return 0; |
1623 | ||
4f367d8a PZ |
1624 | return 1; |
1625 | } | |
1626 | ||
1627 | static int | |
1628 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1629 | struct held_lock *next) | |
1630 | { | |
1631 | #define LOCKDEP_STATE(__STATE) \ | |
1632 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1633 | return 0; |
4f367d8a PZ |
1634 | #include "lockdep_states.h" |
1635 | #undef LOCKDEP_STATE | |
cf40bd16 | 1636 | |
8e18257d PZ |
1637 | return 1; |
1638 | } | |
1639 | ||
1640 | static void inc_chains(void) | |
1641 | { | |
1642 | if (current->hardirq_context) | |
1643 | nr_hardirq_chains++; | |
1644 | else { | |
1645 | if (current->softirq_context) | |
1646 | nr_softirq_chains++; | |
1647 | else | |
1648 | nr_process_chains++; | |
1649 | } | |
1650 | } | |
1651 | ||
1652 | #else | |
1653 | ||
1654 | static inline int | |
1655 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1656 | struct held_lock *next) | |
1657 | { | |
1658 | return 1; | |
1659 | } | |
1660 | ||
1661 | static inline void inc_chains(void) | |
1662 | { | |
1663 | nr_process_chains++; | |
1664 | } | |
1665 | ||
fbb9ce95 IM |
1666 | #endif |
1667 | ||
48702ecf SR |
1668 | static void |
1669 | print_deadlock_scenario(struct held_lock *nxt, | |
1670 | struct held_lock *prv) | |
1671 | { | |
1672 | struct lock_class *next = hlock_class(nxt); | |
1673 | struct lock_class *prev = hlock_class(prv); | |
1674 | ||
1675 | printk(" Possible unsafe locking scenario:\n\n"); | |
1676 | printk(" CPU0\n"); | |
1677 | printk(" ----\n"); | |
1678 | printk(" lock("); | |
1679 | __print_lock_name(prev); | |
1680 | printk(");\n"); | |
1681 | printk(" lock("); | |
1682 | __print_lock_name(next); | |
1683 | printk(");\n"); | |
1684 | printk("\n *** DEADLOCK ***\n\n"); | |
1685 | printk(" May be due to missing lock nesting notation\n\n"); | |
1686 | } | |
1687 | ||
fbb9ce95 IM |
1688 | static int |
1689 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1690 | struct held_lock *next) | |
1691 | { | |
74c383f1 | 1692 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1693 | return 0; |
1694 | ||
1695 | printk("\n=============================================\n"); | |
1696 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1697 | print_kernel_version(); |
fbb9ce95 IM |
1698 | printk( "---------------------------------------------\n"); |
1699 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1700 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1701 | print_lock(next); |
1702 | printk("\nbut task is already holding lock:\n"); | |
1703 | print_lock(prev); | |
1704 | ||
1705 | printk("\nother info that might help us debug this:\n"); | |
48702ecf | 1706 | print_deadlock_scenario(next, prev); |
fbb9ce95 IM |
1707 | lockdep_print_held_locks(curr); |
1708 | ||
1709 | printk("\nstack backtrace:\n"); | |
1710 | dump_stack(); | |
1711 | ||
1712 | return 0; | |
1713 | } | |
1714 | ||
1715 | /* | |
1716 | * Check whether we are holding such a class already. | |
1717 | * | |
1718 | * (Note that this has to be done separately, because the graph cannot | |
1719 | * detect such classes of deadlocks.) | |
1720 | * | |
1721 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1722 | */ | |
1723 | static int | |
1724 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1725 | struct lockdep_map *next_instance, int read) | |
1726 | { | |
1727 | struct held_lock *prev; | |
7531e2f3 | 1728 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1729 | int i; |
1730 | ||
1731 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1732 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1733 | |
1734 | if (prev->instance == next->nest_lock) | |
1735 | nest = prev; | |
1736 | ||
f82b217e | 1737 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1738 | continue; |
7531e2f3 | 1739 | |
fbb9ce95 IM |
1740 | /* |
1741 | * Allow read-after-read recursion of the same | |
6c9076ec | 1742 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1743 | */ |
6c9076ec | 1744 | if ((read == 2) && prev->read) |
fbb9ce95 | 1745 | return 2; |
7531e2f3 PZ |
1746 | |
1747 | /* | |
1748 | * We're holding the nest_lock, which serializes this lock's | |
1749 | * nesting behaviour. | |
1750 | */ | |
1751 | if (nest) | |
1752 | return 2; | |
1753 | ||
fbb9ce95 IM |
1754 | return print_deadlock_bug(curr, prev, next); |
1755 | } | |
1756 | return 1; | |
1757 | } | |
1758 | ||
1759 | /* | |
1760 | * There was a chain-cache miss, and we are about to add a new dependency | |
1761 | * to a previous lock. We recursively validate the following rules: | |
1762 | * | |
1763 | * - would the adding of the <prev> -> <next> dependency create a | |
1764 | * circular dependency in the graph? [== circular deadlock] | |
1765 | * | |
1766 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1767 | * (in the full backwards-subgraph starting at <prev>) with any | |
1768 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1769 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1770 | * | |
1771 | * - does the new prev->next dependency connect any softirq-safe lock | |
1772 | * (in the full backwards-subgraph starting at <prev>) with any | |
1773 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1774 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1775 | * | |
1776 | * any of these scenarios could lead to a deadlock. | |
1777 | * | |
1778 | * Then if all the validations pass, we add the forwards and backwards | |
1779 | * dependency. | |
1780 | */ | |
1781 | static int | |
1782 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
4726f2a6 | 1783 | struct held_lock *next, int distance, int trylock_loop) |
fbb9ce95 IM |
1784 | { |
1785 | struct lock_list *entry; | |
1786 | int ret; | |
db0002a3 ML |
1787 | struct lock_list this; |
1788 | struct lock_list *uninitialized_var(target_entry); | |
4726f2a6 YZ |
1789 | /* |
1790 | * Static variable, serialized by the graph_lock(). | |
1791 | * | |
1792 | * We use this static variable to save the stack trace in case | |
1793 | * we call into this function multiple times due to encountering | |
1794 | * trylocks in the held lock stack. | |
1795 | */ | |
1796 | static struct stack_trace trace; | |
fbb9ce95 IM |
1797 | |
1798 | /* | |
1799 | * Prove that the new <prev> -> <next> dependency would not | |
1800 | * create a circular dependency in the graph. (We do this by | |
1801 | * forward-recursing into the graph starting at <next>, and | |
1802 | * checking whether we can reach <prev>.) | |
1803 | * | |
1804 | * We are using global variables to control the recursion, to | |
1805 | * keep the stackframe size of the recursive functions low: | |
1806 | */ | |
db0002a3 ML |
1807 | this.class = hlock_class(next); |
1808 | this.parent = NULL; | |
1809 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1810 | if (unlikely(!ret)) | |
1811 | return print_circular_bug(&this, target_entry, next, prev); | |
1812 | else if (unlikely(ret < 0)) | |
1813 | return print_bfs_bug(ret); | |
c94aa5ca | 1814 | |
8e18257d | 1815 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1816 | return 0; |
1817 | ||
fbb9ce95 IM |
1818 | /* |
1819 | * For recursive read-locks we do all the dependency checks, | |
1820 | * but we dont store read-triggered dependencies (only | |
1821 | * write-triggered dependencies). This ensures that only the | |
1822 | * write-side dependencies matter, and that if for example a | |
1823 | * write-lock never takes any other locks, then the reads are | |
1824 | * equivalent to a NOP. | |
1825 | */ | |
1826 | if (next->read == 2 || prev->read == 2) | |
1827 | return 1; | |
1828 | /* | |
1829 | * Is the <prev> -> <next> dependency already present? | |
1830 | * | |
1831 | * (this may occur even though this is a new chain: consider | |
1832 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1833 | * chains - the second one will be new, but L1 already has | |
1834 | * L2 added to its dependency list, due to the first chain.) | |
1835 | */ | |
f82b217e DJ |
1836 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1837 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1838 | if (distance == 1) |
1839 | entry->distance = 1; | |
fbb9ce95 | 1840 | return 2; |
068135e6 | 1841 | } |
fbb9ce95 IM |
1842 | } |
1843 | ||
4726f2a6 YZ |
1844 | if (!trylock_loop && !save_trace(&trace)) |
1845 | return 0; | |
1846 | ||
fbb9ce95 IM |
1847 | /* |
1848 | * Ok, all validations passed, add the new lock | |
1849 | * to the previous lock's dependency list: | |
1850 | */ | |
f82b217e DJ |
1851 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1852 | &hlock_class(prev)->locks_after, | |
4726f2a6 | 1853 | next->acquire_ip, distance, &trace); |
068135e6 | 1854 | |
fbb9ce95 IM |
1855 | if (!ret) |
1856 | return 0; | |
910b1b2e | 1857 | |
f82b217e DJ |
1858 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1859 | &hlock_class(next)->locks_before, | |
4726f2a6 | 1860 | next->acquire_ip, distance, &trace); |
910b1b2e JP |
1861 | if (!ret) |
1862 | return 0; | |
fbb9ce95 IM |
1863 | |
1864 | /* | |
8e18257d PZ |
1865 | * Debugging printouts: |
1866 | */ | |
f82b217e | 1867 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1868 | graph_unlock(); |
1869 | printk("\n new dependency: "); | |
f82b217e | 1870 | print_lock_name(hlock_class(prev)); |
8e18257d | 1871 | printk(" => "); |
f82b217e | 1872 | print_lock_name(hlock_class(next)); |
8e18257d | 1873 | printk("\n"); |
fbb9ce95 | 1874 | dump_stack(); |
8e18257d | 1875 | return graph_lock(); |
fbb9ce95 | 1876 | } |
8e18257d PZ |
1877 | return 1; |
1878 | } | |
fbb9ce95 | 1879 | |
8e18257d PZ |
1880 | /* |
1881 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1882 | * The ones that are relevant are (in increasing distance from curr): | |
1883 | * all consecutive trylock entries and the final non-trylock entry - or | |
1884 | * the end of this context's lock-chain - whichever comes first. | |
1885 | */ | |
1886 | static int | |
1887 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1888 | { | |
1889 | int depth = curr->lockdep_depth; | |
4726f2a6 | 1890 | int trylock_loop = 0; |
8e18257d | 1891 | struct held_lock *hlock; |
d6d897ce | 1892 | |
fbb9ce95 | 1893 | /* |
8e18257d PZ |
1894 | * Debugging checks. |
1895 | * | |
1896 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1897 | */ |
8e18257d PZ |
1898 | if (!depth) |
1899 | goto out_bug; | |
fbb9ce95 | 1900 | /* |
8e18257d PZ |
1901 | * At least two relevant locks must exist for this |
1902 | * to be a head: | |
fbb9ce95 | 1903 | */ |
8e18257d PZ |
1904 | if (curr->held_locks[depth].irq_context != |
1905 | curr->held_locks[depth-1].irq_context) | |
1906 | goto out_bug; | |
74c383f1 | 1907 | |
8e18257d PZ |
1908 | for (;;) { |
1909 | int distance = curr->lockdep_depth - depth + 1; | |
1910 | hlock = curr->held_locks + depth-1; | |
1911 | /* | |
1912 | * Only non-recursive-read entries get new dependencies | |
1913 | * added: | |
1914 | */ | |
1915 | if (hlock->read != 2) { | |
4726f2a6 YZ |
1916 | if (!check_prev_add(curr, hlock, next, |
1917 | distance, trylock_loop)) | |
8e18257d PZ |
1918 | return 0; |
1919 | /* | |
1920 | * Stop after the first non-trylock entry, | |
1921 | * as non-trylock entries have added their | |
1922 | * own direct dependencies already, so this | |
1923 | * lock is connected to them indirectly: | |
1924 | */ | |
1925 | if (!hlock->trylock) | |
1926 | break; | |
74c383f1 | 1927 | } |
8e18257d PZ |
1928 | depth--; |
1929 | /* | |
1930 | * End of lock-stack? | |
1931 | */ | |
1932 | if (!depth) | |
1933 | break; | |
1934 | /* | |
1935 | * Stop the search if we cross into another context: | |
1936 | */ | |
1937 | if (curr->held_locks[depth].irq_context != | |
1938 | curr->held_locks[depth-1].irq_context) | |
1939 | break; | |
4726f2a6 | 1940 | trylock_loop = 1; |
fbb9ce95 | 1941 | } |
8e18257d PZ |
1942 | return 1; |
1943 | out_bug: | |
1944 | if (!debug_locks_off_graph_unlock()) | |
1945 | return 0; | |
fbb9ce95 | 1946 | |
8e18257d | 1947 | WARN_ON(1); |
fbb9ce95 | 1948 | |
8e18257d | 1949 | return 0; |
fbb9ce95 IM |
1950 | } |
1951 | ||
8e18257d | 1952 | unsigned long nr_lock_chains; |
443cd507 | 1953 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1954 | int nr_chain_hlocks; |
443cd507 HY |
1955 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1956 | ||
1957 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1958 | { | |
1959 | return lock_classes + chain_hlocks[chain->base + i]; | |
1960 | } | |
8e18257d | 1961 | |
fbb9ce95 IM |
1962 | /* |
1963 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1964 | * add it and return 1 - in this case the new dependency chain is |
1965 | * validated. If the key is already hashed, return 0. | |
1966 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1967 | */ |
443cd507 HY |
1968 | static inline int lookup_chain_cache(struct task_struct *curr, |
1969 | struct held_lock *hlock, | |
1970 | u64 chain_key) | |
fbb9ce95 | 1971 | { |
f82b217e | 1972 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1973 | struct list_head *hash_head = chainhashentry(chain_key); |
1974 | struct lock_chain *chain; | |
443cd507 | 1975 | struct held_lock *hlock_curr, *hlock_next; |
e0944ee6 | 1976 | int i, j; |
fbb9ce95 | 1977 | |
381a2292 JP |
1978 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1979 | return 0; | |
fbb9ce95 IM |
1980 | /* |
1981 | * We can walk it lock-free, because entries only get added | |
1982 | * to the hash: | |
1983 | */ | |
1984 | list_for_each_entry(chain, hash_head, entry) { | |
1985 | if (chain->chain_key == chain_key) { | |
1986 | cache_hit: | |
bd6d29c2 | 1987 | debug_atomic_inc(chain_lookup_hits); |
81fc685a | 1988 | if (very_verbose(class)) |
755cd900 AM |
1989 | printk("\nhash chain already cached, key: " |
1990 | "%016Lx tail class: [%p] %s\n", | |
1991 | (unsigned long long)chain_key, | |
1992 | class->key, class->name); | |
fbb9ce95 IM |
1993 | return 0; |
1994 | } | |
1995 | } | |
81fc685a | 1996 | if (very_verbose(class)) |
755cd900 AM |
1997 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1998 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1999 | /* |
2000 | * Allocate a new chain entry from the static array, and add | |
2001 | * it to the hash: | |
2002 | */ | |
74c383f1 IM |
2003 | if (!graph_lock()) |
2004 | return 0; | |
fbb9ce95 IM |
2005 | /* |
2006 | * We have to walk the chain again locked - to avoid duplicates: | |
2007 | */ | |
2008 | list_for_each_entry(chain, hash_head, entry) { | |
2009 | if (chain->chain_key == chain_key) { | |
74c383f1 | 2010 | graph_unlock(); |
fbb9ce95 IM |
2011 | goto cache_hit; |
2012 | } | |
2013 | } | |
2014 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
2015 | if (!debug_locks_off_graph_unlock()) |
2016 | return 0; | |
2017 | ||
fbb9ce95 IM |
2018 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
2019 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2020 | dump_stack(); |
fbb9ce95 IM |
2021 | return 0; |
2022 | } | |
2023 | chain = lock_chains + nr_lock_chains++; | |
2024 | chain->chain_key = chain_key; | |
443cd507 HY |
2025 | chain->irq_context = hlock->irq_context; |
2026 | /* Find the first held_lock of current chain */ | |
2027 | hlock_next = hlock; | |
2028 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
2029 | hlock_curr = curr->held_locks + i; | |
2030 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
2031 | break; | |
2032 | hlock_next = hlock; | |
2033 | } | |
2034 | i++; | |
2035 | chain->depth = curr->lockdep_depth + 1 - i; | |
e0944ee6 SR |
2036 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
2037 | chain->base = nr_chain_hlocks; | |
2038 | nr_chain_hlocks += chain->depth; | |
443cd507 | 2039 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 2040 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
2041 | chain_hlocks[chain->base + j] = lock_id; |
2042 | } | |
2043 | chain_hlocks[chain->base + j] = class - lock_classes; | |
2044 | } | |
fbb9ce95 | 2045 | list_add_tail_rcu(&chain->entry, hash_head); |
bd6d29c2 | 2046 | debug_atomic_inc(chain_lookup_misses); |
8e18257d PZ |
2047 | inc_chains(); |
2048 | ||
2049 | return 1; | |
2050 | } | |
2051 | ||
2052 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 2053 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
2054 | { |
2055 | /* | |
2056 | * Trylock needs to maintain the stack of held locks, but it | |
2057 | * does not add new dependencies, because trylock can be done | |
2058 | * in any order. | |
2059 | * | |
2060 | * We look up the chain_key and do the O(N^2) check and update of | |
2061 | * the dependencies only if this is a new dependency chain. | |
2062 | * (If lookup_chain_cache() returns with 1 it acquires | |
2063 | * graph_lock for us) | |
2064 | */ | |
2065 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 2066 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
2067 | /* |
2068 | * Check whether last held lock: | |
2069 | * | |
2070 | * - is irq-safe, if this lock is irq-unsafe | |
2071 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2072 | * | |
2073 | * And check whether the new lock's dependency graph | |
2074 | * could lead back to the previous lock. | |
2075 | * | |
2076 | * any of these scenarios could lead to a deadlock. If | |
2077 | * All validations | |
2078 | */ | |
2079 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
2080 | ||
2081 | if (!ret) | |
2082 | return 0; | |
2083 | /* | |
2084 | * Mark recursive read, as we jump over it when | |
2085 | * building dependencies (just like we jump over | |
2086 | * trylock entries): | |
2087 | */ | |
2088 | if (ret == 2) | |
2089 | hlock->read = 2; | |
2090 | /* | |
2091 | * Add dependency only if this lock is not the head | |
2092 | * of the chain, and if it's not a secondary read-lock: | |
2093 | */ | |
2094 | if (!chain_head && ret != 2) | |
2095 | if (!check_prevs_add(curr, hlock)) | |
2096 | return 0; | |
2097 | graph_unlock(); | |
2098 | } else | |
2099 | /* after lookup_chain_cache(): */ | |
2100 | if (unlikely(!debug_locks)) | |
2101 | return 0; | |
fbb9ce95 IM |
2102 | |
2103 | return 1; | |
2104 | } | |
8e18257d PZ |
2105 | #else |
2106 | static inline int validate_chain(struct task_struct *curr, | |
2107 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 2108 | int chain_head, u64 chain_key) |
8e18257d PZ |
2109 | { |
2110 | return 1; | |
2111 | } | |
ca58abcb | 2112 | #endif |
fbb9ce95 IM |
2113 | |
2114 | /* | |
2115 | * We are building curr_chain_key incrementally, so double-check | |
2116 | * it from scratch, to make sure that it's done correctly: | |
2117 | */ | |
1d09daa5 | 2118 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
2119 | { |
2120 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2121 | struct held_lock *hlock, *prev_hlock = NULL; | |
2122 | unsigned int i, id; | |
2123 | u64 chain_key = 0; | |
2124 | ||
2125 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2126 | hlock = curr->held_locks + i; | |
2127 | if (chain_key != hlock->prev_chain_key) { | |
2128 | debug_locks_off(); | |
2df8b1d6 | 2129 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2130 | curr->lockdep_depth, i, |
2131 | (unsigned long long)chain_key, | |
2132 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
2133 | return; |
2134 | } | |
f82b217e | 2135 | id = hlock->class_idx - 1; |
381a2292 JP |
2136 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
2137 | return; | |
2138 | ||
fbb9ce95 IM |
2139 | if (prev_hlock && (prev_hlock->irq_context != |
2140 | hlock->irq_context)) | |
2141 | chain_key = 0; | |
2142 | chain_key = iterate_chain_key(chain_key, id); | |
2143 | prev_hlock = hlock; | |
2144 | } | |
2145 | if (chain_key != curr->curr_chain_key) { | |
2146 | debug_locks_off(); | |
2df8b1d6 | 2147 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
2148 | curr->lockdep_depth, i, |
2149 | (unsigned long long)chain_key, | |
2150 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
2151 | } |
2152 | #endif | |
2153 | } | |
2154 | ||
282b5c2f SR |
2155 | static void |
2156 | print_usage_bug_scenario(struct held_lock *lock) | |
2157 | { | |
2158 | struct lock_class *class = hlock_class(lock); | |
2159 | ||
2160 | printk(" Possible unsafe locking scenario:\n\n"); | |
2161 | printk(" CPU0\n"); | |
2162 | printk(" ----\n"); | |
2163 | printk(" lock("); | |
2164 | __print_lock_name(class); | |
2165 | printk(");\n"); | |
2166 | printk(" <Interrupt>\n"); | |
2167 | printk(" lock("); | |
2168 | __print_lock_name(class); | |
2169 | printk(");\n"); | |
2170 | printk("\n *** DEADLOCK ***\n\n"); | |
2171 | } | |
2172 | ||
8e18257d PZ |
2173 | static int |
2174 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
2175 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
2176 | { | |
2177 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
2178 | return 0; | |
2179 | ||
2180 | printk("\n=================================\n"); | |
2181 | printk( "[ INFO: inconsistent lock state ]\n"); | |
2182 | print_kernel_version(); | |
2183 | printk( "---------------------------------\n"); | |
2184 | ||
2185 | printk("inconsistent {%s} -> {%s} usage.\n", | |
2186 | usage_str[prev_bit], usage_str[new_bit]); | |
2187 | ||
2188 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 2189 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
2190 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
2191 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
2192 | trace_hardirqs_enabled(curr), | |
2193 | trace_softirqs_enabled(curr)); | |
2194 | print_lock(this); | |
2195 | ||
2196 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 2197 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
2198 | |
2199 | print_irqtrace_events(curr); | |
2200 | printk("\nother info that might help us debug this:\n"); | |
282b5c2f SR |
2201 | print_usage_bug_scenario(this); |
2202 | ||
8e18257d PZ |
2203 | lockdep_print_held_locks(curr); |
2204 | ||
2205 | printk("\nstack backtrace:\n"); | |
2206 | dump_stack(); | |
2207 | ||
2208 | return 0; | |
2209 | } | |
2210 | ||
2211 | /* | |
2212 | * Print out an error if an invalid bit is set: | |
2213 | */ | |
2214 | static inline int | |
2215 | valid_state(struct task_struct *curr, struct held_lock *this, | |
2216 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
2217 | { | |
f82b217e | 2218 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
2219 | return print_usage_bug(curr, this, bad_bit, new_bit); |
2220 | return 1; | |
2221 | } | |
2222 | ||
2223 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
2224 | enum lock_usage_bit new_bit); | |
2225 | ||
81d68a96 | 2226 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
2227 | |
2228 | /* | |
2229 | * print irq inversion bug: | |
2230 | */ | |
2231 | static int | |
24208ca7 ML |
2232 | print_irq_inversion_bug(struct task_struct *curr, |
2233 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
2234 | struct held_lock *this, int forwards, |
2235 | const char *irqclass) | |
2236 | { | |
dad3d743 SR |
2237 | struct lock_list *entry = other; |
2238 | struct lock_list *middle = NULL; | |
2239 | int depth; | |
2240 | ||
74c383f1 | 2241 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
2242 | return 0; |
2243 | ||
2244 | printk("\n=========================================================\n"); | |
2245 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2246 | print_kernel_version(); |
fbb9ce95 IM |
2247 | printk( "---------------------------------------------------------\n"); |
2248 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2249 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2250 | print_lock(this); |
2251 | if (forwards) | |
26575e28 | 2252 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2253 | else |
26575e28 | 2254 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2255 | print_lock_name(other->class); |
fbb9ce95 IM |
2256 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2257 | ||
2258 | printk("\nother info that might help us debug this:\n"); | |
dad3d743 SR |
2259 | |
2260 | /* Find a middle lock (if one exists) */ | |
2261 | depth = get_lock_depth(other); | |
2262 | do { | |
2263 | if (depth == 0 && (entry != root)) { | |
2264 | printk("lockdep:%s bad path found in chain graph\n", __func__); | |
2265 | break; | |
2266 | } | |
2267 | middle = entry; | |
2268 | entry = get_lock_parent(entry); | |
2269 | depth--; | |
2270 | } while (entry && entry != root && (depth >= 0)); | |
2271 | if (forwards) | |
2272 | print_irq_lock_scenario(root, other, | |
2273 | middle ? middle->class : root->class, other->class); | |
2274 | else | |
2275 | print_irq_lock_scenario(other, root, | |
2276 | middle ? middle->class : other->class, root->class); | |
2277 | ||
fbb9ce95 IM |
2278 | lockdep_print_held_locks(curr); |
2279 | ||
24208ca7 ML |
2280 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2281 | if (!save_trace(&root->trace)) | |
2282 | return 0; | |
2283 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2284 | |
2285 | printk("\nstack backtrace:\n"); | |
2286 | dump_stack(); | |
2287 | ||
2288 | return 0; | |
2289 | } | |
2290 | ||
2291 | /* | |
2292 | * Prove that in the forwards-direction subgraph starting at <this> | |
2293 | * there is no lock matching <mask>: | |
2294 | */ | |
2295 | static int | |
2296 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2297 | enum lock_usage_bit bit, const char *irqclass) | |
2298 | { | |
2299 | int ret; | |
d7aaba14 ML |
2300 | struct lock_list root; |
2301 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2302 | |
d7aaba14 ML |
2303 | root.parent = NULL; |
2304 | root.class = hlock_class(this); | |
2305 | ret = find_usage_forwards(&root, bit, &target_entry); | |
af012961 PZ |
2306 | if (ret < 0) |
2307 | return print_bfs_bug(ret); | |
2308 | if (ret == 1) | |
2309 | return ret; | |
fbb9ce95 | 2310 | |
24208ca7 | 2311 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2312 | this, 1, irqclass); |
fbb9ce95 IM |
2313 | } |
2314 | ||
2315 | /* | |
2316 | * Prove that in the backwards-direction subgraph starting at <this> | |
2317 | * there is no lock matching <mask>: | |
2318 | */ | |
2319 | static int | |
2320 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2321 | enum lock_usage_bit bit, const char *irqclass) | |
2322 | { | |
2323 | int ret; | |
d7aaba14 ML |
2324 | struct lock_list root; |
2325 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2326 | |
d7aaba14 ML |
2327 | root.parent = NULL; |
2328 | root.class = hlock_class(this); | |
2329 | ret = find_usage_backwards(&root, bit, &target_entry); | |
af012961 PZ |
2330 | if (ret < 0) |
2331 | return print_bfs_bug(ret); | |
2332 | if (ret == 1) | |
2333 | return ret; | |
fbb9ce95 | 2334 | |
24208ca7 | 2335 | return print_irq_inversion_bug(curr, &root, target_entry, |
48d50674 | 2336 | this, 0, irqclass); |
fbb9ce95 IM |
2337 | } |
2338 | ||
3117df04 | 2339 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2340 | { |
2341 | printk("irq event stamp: %u\n", curr->irq_events); | |
2342 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2343 | print_ip_sym(curr->hardirq_enable_ip); | |
2344 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2345 | print_ip_sym(curr->hardirq_disable_ip); | |
2346 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2347 | print_ip_sym(curr->softirq_enable_ip); | |
2348 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2349 | print_ip_sym(curr->softirq_disable_ip); | |
2350 | } | |
2351 | ||
cd95302d | 2352 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2353 | { |
8e18257d PZ |
2354 | #if HARDIRQ_VERBOSE |
2355 | return class_filter(class); | |
2356 | #endif | |
fbb9ce95 IM |
2357 | return 0; |
2358 | } | |
2359 | ||
cd95302d | 2360 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2361 | { |
8e18257d PZ |
2362 | #if SOFTIRQ_VERBOSE |
2363 | return class_filter(class); | |
2364 | #endif | |
2365 | return 0; | |
fbb9ce95 IM |
2366 | } |
2367 | ||
cd95302d | 2368 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2369 | { |
2370 | #if RECLAIM_VERBOSE | |
2371 | return class_filter(class); | |
2372 | #endif | |
2373 | return 0; | |
2374 | } | |
2375 | ||
fbb9ce95 IM |
2376 | #define STRICT_READ_CHECKS 1 |
2377 | ||
cd95302d PZ |
2378 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2379 | #define LOCKDEP_STATE(__STATE) \ | |
2380 | __STATE##_verbose, | |
2381 | #include "lockdep_states.h" | |
2382 | #undef LOCKDEP_STATE | |
2383 | }; | |
2384 | ||
2385 | static inline int state_verbose(enum lock_usage_bit bit, | |
2386 | struct lock_class *class) | |
2387 | { | |
2388 | return state_verbose_f[bit >> 2](class); | |
2389 | } | |
2390 | ||
42c50d54 PZ |
2391 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2392 | enum lock_usage_bit bit, const char *name); | |
2393 | ||
6a6904d3 | 2394 | static int |
1c21f14e PZ |
2395 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2396 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2397 | { |
f989209e | 2398 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2399 | int read = new_bit & 1; |
42c50d54 PZ |
2400 | int dir = new_bit & 2; |
2401 | ||
38aa2714 PZ |
2402 | /* |
2403 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2404 | * has ENABLED state, which would allow recursion deadlocks. | |
2405 | * | |
2406 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2407 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2408 | */ | |
42c50d54 PZ |
2409 | check_usage_f usage = dir ? |
2410 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2411 | |
38aa2714 PZ |
2412 | /* |
2413 | * Validate that this particular lock does not have conflicting | |
2414 | * usage states. | |
2415 | */ | |
6a6904d3 PZ |
2416 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2417 | return 0; | |
42c50d54 | 2418 | |
38aa2714 PZ |
2419 | /* |
2420 | * Validate that the lock dependencies don't have conflicting usage | |
2421 | * states. | |
2422 | */ | |
2423 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2424 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2425 | return 0; |
780e820b | 2426 | |
38aa2714 PZ |
2427 | /* |
2428 | * Check for read in write conflicts | |
2429 | */ | |
2430 | if (!read) { | |
2431 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2432 | return 0; | |
2433 | ||
2434 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2435 | !usage(curr, this, excl_bit + 1, |
2436 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2437 | return 0; |
2438 | } | |
780e820b | 2439 | |
cd95302d | 2440 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2441 | return 2; |
2442 | ||
2443 | return 1; | |
2444 | } | |
2445 | ||
cf40bd16 | 2446 | enum mark_type { |
36bfb9bb PZ |
2447 | #define LOCKDEP_STATE(__STATE) __STATE, |
2448 | #include "lockdep_states.h" | |
2449 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2450 | }; |
2451 | ||
fbb9ce95 IM |
2452 | /* |
2453 | * Mark all held locks with a usage bit: | |
2454 | */ | |
1d09daa5 | 2455 | static int |
cf40bd16 | 2456 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2457 | { |
2458 | enum lock_usage_bit usage_bit; | |
2459 | struct held_lock *hlock; | |
2460 | int i; | |
2461 | ||
2462 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2463 | hlock = curr->held_locks + i; | |
2464 | ||
cf2ad4d1 PZ |
2465 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2466 | if (hlock->read) | |
2467 | usage_bit += 1; /* READ */ | |
2468 | ||
2469 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2470 | |
70a0686a | 2471 | if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys) |
efbe2eee PZ |
2472 | continue; |
2473 | ||
4ff773bb | 2474 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2475 | return 0; |
2476 | } | |
2477 | ||
2478 | return 1; | |
2479 | } | |
2480 | ||
fbb9ce95 IM |
2481 | /* |
2482 | * Hardirqs will be enabled: | |
2483 | */ | |
dd4e5d3a | 2484 | static void __trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2485 | { |
2486 | struct task_struct *curr = current; | |
fbb9ce95 | 2487 | |
fbb9ce95 IM |
2488 | /* we'll do an OFF -> ON transition: */ |
2489 | curr->hardirqs_enabled = 1; | |
fbb9ce95 | 2490 | |
fbb9ce95 IM |
2491 | /* |
2492 | * We are going to turn hardirqs on, so set the | |
2493 | * usage bit for all held locks: | |
2494 | */ | |
cf40bd16 | 2495 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2496 | return; |
2497 | /* | |
2498 | * If we have softirqs enabled, then set the usage | |
2499 | * bit for all held locks. (disabled hardirqs prevented | |
2500 | * this bit from being set before) | |
2501 | */ | |
2502 | if (curr->softirqs_enabled) | |
cf40bd16 | 2503 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2504 | return; |
2505 | ||
8e18257d PZ |
2506 | curr->hardirq_enable_ip = ip; |
2507 | curr->hardirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2508 | debug_atomic_inc(hardirqs_on_events); |
8e18257d | 2509 | } |
dd4e5d3a PZ |
2510 | |
2511 | void trace_hardirqs_on_caller(unsigned long ip) | |
2512 | { | |
2513 | time_hardirqs_on(CALLER_ADDR0, ip); | |
2514 | ||
2515 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
2516 | return; | |
2517 | ||
7d36b26b PZ |
2518 | if (unlikely(current->hardirqs_enabled)) { |
2519 | /* | |
2520 | * Neither irq nor preemption are disabled here | |
2521 | * so this is racy by nature but losing one hit | |
2522 | * in a stat is not a big deal. | |
2523 | */ | |
2524 | __debug_atomic_inc(redundant_hardirqs_on); | |
2525 | return; | |
2526 | } | |
2527 | ||
dd4e5d3a PZ |
2528 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
2529 | return; | |
2530 | ||
7d36b26b PZ |
2531 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
2532 | return; | |
2533 | ||
2534 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2535 | return; | |
2536 | ||
dd4e5d3a PZ |
2537 | current->lockdep_recursion = 1; |
2538 | __trace_hardirqs_on_caller(ip); | |
2539 | current->lockdep_recursion = 0; | |
2540 | } | |
81d68a96 | 2541 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2542 | |
1d09daa5 | 2543 | void trace_hardirqs_on(void) |
81d68a96 SR |
2544 | { |
2545 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2546 | } | |
8e18257d PZ |
2547 | EXPORT_SYMBOL(trace_hardirqs_on); |
2548 | ||
2549 | /* | |
2550 | * Hardirqs were disabled: | |
2551 | */ | |
6afe40b4 | 2552 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2553 | { |
2554 | struct task_struct *curr = current; | |
2555 | ||
6afe40b4 | 2556 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2557 | |
8e18257d PZ |
2558 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2559 | return; | |
2560 | ||
2561 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2562 | return; | |
2563 | ||
2564 | if (curr->hardirqs_enabled) { | |
2565 | /* | |
2566 | * We have done an ON -> OFF transition: | |
2567 | */ | |
2568 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2569 | curr->hardirq_disable_ip = ip; |
8e18257d | 2570 | curr->hardirq_disable_event = ++curr->irq_events; |
bd6d29c2 | 2571 | debug_atomic_inc(hardirqs_off_events); |
8e18257d | 2572 | } else |
bd6d29c2 | 2573 | debug_atomic_inc(redundant_hardirqs_off); |
8e18257d | 2574 | } |
81d68a96 | 2575 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2576 | |
1d09daa5 | 2577 | void trace_hardirqs_off(void) |
81d68a96 SR |
2578 | { |
2579 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2580 | } | |
8e18257d PZ |
2581 | EXPORT_SYMBOL(trace_hardirqs_off); |
2582 | ||
2583 | /* | |
2584 | * Softirqs will be enabled: | |
2585 | */ | |
2586 | void trace_softirqs_on(unsigned long ip) | |
2587 | { | |
2588 | struct task_struct *curr = current; | |
2589 | ||
dd4e5d3a | 2590 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2591 | return; |
2592 | ||
2593 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2594 | return; | |
2595 | ||
2596 | if (curr->softirqs_enabled) { | |
bd6d29c2 | 2597 | debug_atomic_inc(redundant_softirqs_on); |
8e18257d PZ |
2598 | return; |
2599 | } | |
2600 | ||
dd4e5d3a | 2601 | current->lockdep_recursion = 1; |
8e18257d PZ |
2602 | /* |
2603 | * We'll do an OFF -> ON transition: | |
2604 | */ | |
2605 | curr->softirqs_enabled = 1; | |
2606 | curr->softirq_enable_ip = ip; | |
2607 | curr->softirq_enable_event = ++curr->irq_events; | |
bd6d29c2 | 2608 | debug_atomic_inc(softirqs_on_events); |
8e18257d PZ |
2609 | /* |
2610 | * We are going to turn softirqs on, so set the | |
2611 | * usage bit for all held locks, if hardirqs are | |
2612 | * enabled too: | |
2613 | */ | |
2614 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2615 | mark_held_locks(curr, SOFTIRQ); |
dd4e5d3a | 2616 | current->lockdep_recursion = 0; |
8e18257d PZ |
2617 | } |
2618 | ||
2619 | /* | |
2620 | * Softirqs were disabled: | |
2621 | */ | |
2622 | void trace_softirqs_off(unsigned long ip) | |
2623 | { | |
2624 | struct task_struct *curr = current; | |
2625 | ||
dd4e5d3a | 2626 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
8e18257d PZ |
2627 | return; |
2628 | ||
2629 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2630 | return; | |
2631 | ||
2632 | if (curr->softirqs_enabled) { | |
2633 | /* | |
2634 | * We have done an ON -> OFF transition: | |
2635 | */ | |
2636 | curr->softirqs_enabled = 0; | |
2637 | curr->softirq_disable_ip = ip; | |
2638 | curr->softirq_disable_event = ++curr->irq_events; | |
bd6d29c2 | 2639 | debug_atomic_inc(softirqs_off_events); |
8e18257d PZ |
2640 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
2641 | } else | |
bd6d29c2 | 2642 | debug_atomic_inc(redundant_softirqs_off); |
8e18257d PZ |
2643 | } |
2644 | ||
2f850181 | 2645 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2646 | { |
2647 | struct task_struct *curr = current; | |
2648 | ||
2649 | if (unlikely(!debug_locks)) | |
2650 | return; | |
2651 | ||
2652 | /* no reclaim without waiting on it */ | |
2653 | if (!(gfp_mask & __GFP_WAIT)) | |
2654 | return; | |
2655 | ||
2656 | /* this guy won't enter reclaim */ | |
2657 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2658 | return; | |
2659 | ||
2660 | /* We're only interested __GFP_FS allocations for now */ | |
2661 | if (!(gfp_mask & __GFP_FS)) | |
2662 | return; | |
2663 | ||
2f850181 | 2664 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2665 | return; |
2666 | ||
2667 | mark_held_locks(curr, RECLAIM_FS); | |
2668 | } | |
2669 | ||
2f850181 PZ |
2670 | static void check_flags(unsigned long flags); |
2671 | ||
2672 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2673 | { | |
2674 | unsigned long flags; | |
2675 | ||
2676 | if (unlikely(current->lockdep_recursion)) | |
2677 | return; | |
2678 | ||
2679 | raw_local_irq_save(flags); | |
2680 | check_flags(flags); | |
2681 | current->lockdep_recursion = 1; | |
2682 | __lockdep_trace_alloc(gfp_mask, flags); | |
2683 | current->lockdep_recursion = 0; | |
2684 | raw_local_irq_restore(flags); | |
2685 | } | |
2686 | ||
8e18257d PZ |
2687 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2688 | { | |
2689 | /* | |
2690 | * If non-trylock use in a hardirq or softirq context, then | |
2691 | * mark the lock as used in these contexts: | |
2692 | */ | |
2693 | if (!hlock->trylock) { | |
2694 | if (hlock->read) { | |
2695 | if (curr->hardirq_context) | |
2696 | if (!mark_lock(curr, hlock, | |
2697 | LOCK_USED_IN_HARDIRQ_READ)) | |
2698 | return 0; | |
2699 | if (curr->softirq_context) | |
2700 | if (!mark_lock(curr, hlock, | |
2701 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2702 | return 0; | |
2703 | } else { | |
2704 | if (curr->hardirq_context) | |
2705 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2706 | return 0; | |
2707 | if (curr->softirq_context) | |
2708 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2709 | return 0; | |
2710 | } | |
2711 | } | |
2712 | if (!hlock->hardirqs_off) { | |
2713 | if (hlock->read) { | |
2714 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2715 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2716 | return 0; |
2717 | if (curr->softirqs_enabled) | |
2718 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2719 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2720 | return 0; |
2721 | } else { | |
2722 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2723 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2724 | return 0; |
2725 | if (curr->softirqs_enabled) | |
2726 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2727 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2728 | return 0; |
2729 | } | |
2730 | } | |
2731 | ||
cf40bd16 NP |
2732 | /* |
2733 | * We reuse the irq context infrastructure more broadly as a general | |
2734 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2735 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2736 | * allocation). | |
2737 | */ | |
2738 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2739 | if (hlock->read) { | |
2740 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2741 | return 0; | |
2742 | } else { | |
2743 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2744 | return 0; | |
2745 | } | |
2746 | } | |
2747 | ||
8e18257d PZ |
2748 | return 1; |
2749 | } | |
2750 | ||
2751 | static int separate_irq_context(struct task_struct *curr, | |
2752 | struct held_lock *hlock) | |
2753 | { | |
2754 | unsigned int depth = curr->lockdep_depth; | |
2755 | ||
2756 | /* | |
2757 | * Keep track of points where we cross into an interrupt context: | |
2758 | */ | |
2759 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2760 | curr->softirq_context; | |
2761 | if (depth) { | |
2762 | struct held_lock *prev_hlock; | |
2763 | ||
2764 | prev_hlock = curr->held_locks + depth-1; | |
2765 | /* | |
2766 | * If we cross into another context, reset the | |
2767 | * hash key (this also prevents the checking and the | |
2768 | * adding of the dependency to 'prev'): | |
2769 | */ | |
2770 | if (prev_hlock->irq_context != hlock->irq_context) | |
2771 | return 1; | |
2772 | } | |
2773 | return 0; | |
fbb9ce95 IM |
2774 | } |
2775 | ||
8e18257d | 2776 | #else |
fbb9ce95 | 2777 | |
8e18257d PZ |
2778 | static inline |
2779 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2780 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2781 | { |
8e18257d PZ |
2782 | WARN_ON(1); |
2783 | return 1; | |
2784 | } | |
fbb9ce95 | 2785 | |
8e18257d PZ |
2786 | static inline int mark_irqflags(struct task_struct *curr, |
2787 | struct held_lock *hlock) | |
2788 | { | |
2789 | return 1; | |
2790 | } | |
fbb9ce95 | 2791 | |
8e18257d PZ |
2792 | static inline int separate_irq_context(struct task_struct *curr, |
2793 | struct held_lock *hlock) | |
2794 | { | |
2795 | return 0; | |
fbb9ce95 IM |
2796 | } |
2797 | ||
868a23a8 PZ |
2798 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2799 | { | |
2800 | } | |
2801 | ||
8e18257d | 2802 | #endif |
fbb9ce95 IM |
2803 | |
2804 | /* | |
8e18257d | 2805 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2806 | */ |
1d09daa5 | 2807 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2808 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2809 | { |
8e18257d | 2810 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2811 | |
2812 | /* | |
8e18257d PZ |
2813 | * If already set then do not dirty the cacheline, |
2814 | * nor do any checks: | |
fbb9ce95 | 2815 | */ |
f82b217e | 2816 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2817 | return 1; |
2818 | ||
2819 | if (!graph_lock()) | |
2820 | return 0; | |
fbb9ce95 | 2821 | /* |
25985edc | 2822 | * Make sure we didn't race: |
fbb9ce95 | 2823 | */ |
f82b217e | 2824 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2825 | graph_unlock(); |
2826 | return 1; | |
2827 | } | |
fbb9ce95 | 2828 | |
f82b217e | 2829 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2830 | |
f82b217e | 2831 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2832 | return 0; |
fbb9ce95 | 2833 | |
8e18257d | 2834 | switch (new_bit) { |
5346417e PZ |
2835 | #define LOCKDEP_STATE(__STATE) \ |
2836 | case LOCK_USED_IN_##__STATE: \ | |
2837 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2838 | case LOCK_ENABLED_##__STATE: \ | |
2839 | case LOCK_ENABLED_##__STATE##_READ: | |
2840 | #include "lockdep_states.h" | |
2841 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2842 | ret = mark_lock_irq(curr, this, new_bit); |
2843 | if (!ret) | |
2844 | return 0; | |
2845 | break; | |
2846 | case LOCK_USED: | |
bd6d29c2 | 2847 | debug_atomic_dec(nr_unused_locks); |
8e18257d PZ |
2848 | break; |
2849 | default: | |
2850 | if (!debug_locks_off_graph_unlock()) | |
2851 | return 0; | |
2852 | WARN_ON(1); | |
2853 | return 0; | |
2854 | } | |
fbb9ce95 | 2855 | |
8e18257d PZ |
2856 | graph_unlock(); |
2857 | ||
2858 | /* | |
2859 | * We must printk outside of the graph_lock: | |
2860 | */ | |
2861 | if (ret == 2) { | |
2862 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2863 | print_lock(this); | |
2864 | print_irqtrace_events(curr); | |
2865 | dump_stack(); | |
2866 | } | |
2867 | ||
2868 | return ret; | |
2869 | } | |
fbb9ce95 IM |
2870 | |
2871 | /* | |
2872 | * Initialize a lock instance's lock-class mapping info: | |
2873 | */ | |
2874 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2875 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2876 | { |
f59de899 | 2877 | memset(lock, 0, sizeof(*lock)); |
62016250 | 2878 | |
c8a25005 PZ |
2879 | #ifdef CONFIG_LOCK_STAT |
2880 | lock->cpu = raw_smp_processor_id(); | |
2881 | #endif | |
2882 | ||
2883 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2884 | lock->name = "NULL"; | |
fbb9ce95 | 2885 | return; |
c8a25005 PZ |
2886 | } |
2887 | ||
2888 | lock->name = name; | |
fbb9ce95 IM |
2889 | |
2890 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2891 | return; | |
fbb9ce95 IM |
2892 | /* |
2893 | * Sanity check, the lock-class key must be persistent: | |
2894 | */ | |
2895 | if (!static_obj(key)) { | |
2896 | printk("BUG: key %p not in .data!\n", key); | |
2897 | DEBUG_LOCKS_WARN_ON(1); | |
2898 | return; | |
2899 | } | |
fbb9ce95 | 2900 | lock->key = key; |
c8a25005 PZ |
2901 | |
2902 | if (unlikely(!debug_locks)) | |
2903 | return; | |
2904 | ||
4dfbb9d8 PZ |
2905 | if (subclass) |
2906 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2907 | } |
fbb9ce95 IM |
2908 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2909 | ||
1704f47b PZ |
2910 | struct lock_class_key __lockdep_no_validate__; |
2911 | ||
fbb9ce95 IM |
2912 | /* |
2913 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2914 | * We maintain the dependency maps and validate the locking attempt: | |
2915 | */ | |
2916 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2917 | int trylock, int read, int check, int hardirqs_off, | |
bb97a91e PZ |
2918 | struct lockdep_map *nest_lock, unsigned long ip, |
2919 | int references) | |
fbb9ce95 IM |
2920 | { |
2921 | struct task_struct *curr = current; | |
d6d897ce | 2922 | struct lock_class *class = NULL; |
fbb9ce95 | 2923 | struct held_lock *hlock; |
fbb9ce95 IM |
2924 | unsigned int depth, id; |
2925 | int chain_head = 0; | |
bb97a91e | 2926 | int class_idx; |
fbb9ce95 IM |
2927 | u64 chain_key; |
2928 | ||
f20786ff PZ |
2929 | if (!prove_locking) |
2930 | check = 1; | |
2931 | ||
fbb9ce95 IM |
2932 | if (unlikely(!debug_locks)) |
2933 | return 0; | |
2934 | ||
2935 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2936 | return 0; | |
2937 | ||
1704f47b PZ |
2938 | if (lock->key == &__lockdep_no_validate__) |
2939 | check = 1; | |
2940 | ||
62016250 HM |
2941 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
2942 | class = lock->class_cache[subclass]; | |
d6d897ce | 2943 | /* |
62016250 | 2944 | * Not cached? |
d6d897ce | 2945 | */ |
fbb9ce95 | 2946 | if (unlikely(!class)) { |
4dfbb9d8 | 2947 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2948 | if (!class) |
2949 | return 0; | |
2950 | } | |
bd6d29c2 | 2951 | atomic_inc((atomic_t *)&class->ops); |
fbb9ce95 IM |
2952 | if (very_verbose(class)) { |
2953 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2954 | if (class->name_version > 1) | |
2955 | printk("#%d", class->name_version); | |
2956 | printk("\n"); | |
2957 | dump_stack(); | |
2958 | } | |
2959 | ||
2960 | /* | |
2961 | * Add the lock to the list of currently held locks. | |
2962 | * (we dont increase the depth just yet, up until the | |
2963 | * dependency checks are done) | |
2964 | */ | |
2965 | depth = curr->lockdep_depth; | |
2966 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2967 | return 0; | |
2968 | ||
bb97a91e PZ |
2969 | class_idx = class - lock_classes + 1; |
2970 | ||
2971 | if (depth) { | |
2972 | hlock = curr->held_locks + depth - 1; | |
2973 | if (hlock->class_idx == class_idx && nest_lock) { | |
2974 | if (hlock->references) | |
2975 | hlock->references++; | |
2976 | else | |
2977 | hlock->references = 2; | |
2978 | ||
2979 | return 1; | |
2980 | } | |
2981 | } | |
2982 | ||
fbb9ce95 | 2983 | hlock = curr->held_locks + depth; |
f82b217e DJ |
2984 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2985 | return 0; | |
bb97a91e | 2986 | hlock->class_idx = class_idx; |
fbb9ce95 IM |
2987 | hlock->acquire_ip = ip; |
2988 | hlock->instance = lock; | |
7531e2f3 | 2989 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2990 | hlock->trylock = trylock; |
2991 | hlock->read = read; | |
2992 | hlock->check = check; | |
6951b12a | 2993 | hlock->hardirqs_off = !!hardirqs_off; |
bb97a91e | 2994 | hlock->references = references; |
f20786ff PZ |
2995 | #ifdef CONFIG_LOCK_STAT |
2996 | hlock->waittime_stamp = 0; | |
3365e779 | 2997 | hlock->holdtime_stamp = lockstat_clock(); |
f20786ff | 2998 | #endif |
fbb9ce95 | 2999 | |
8e18257d PZ |
3000 | if (check == 2 && !mark_irqflags(curr, hlock)) |
3001 | return 0; | |
3002 | ||
fbb9ce95 | 3003 | /* mark it as used: */ |
4ff773bb | 3004 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 3005 | return 0; |
8e18257d | 3006 | |
fbb9ce95 | 3007 | /* |
17aacfb9 | 3008 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
3009 | * lock keys along the dependency chain. We save the hash value |
3010 | * at every step so that we can get the current hash easily | |
3011 | * after unlock. The chain hash is then used to cache dependency | |
3012 | * results. | |
3013 | * | |
3014 | * The 'key ID' is what is the most compact key value to drive | |
3015 | * the hash, not class->key. | |
3016 | */ | |
3017 | id = class - lock_classes; | |
3018 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
3019 | return 0; | |
3020 | ||
3021 | chain_key = curr->curr_chain_key; | |
3022 | if (!depth) { | |
3023 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
3024 | return 0; | |
3025 | chain_head = 1; | |
3026 | } | |
3027 | ||
3028 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
3029 | if (separate_irq_context(curr, hlock)) { |
3030 | chain_key = 0; | |
3031 | chain_head = 1; | |
fbb9ce95 | 3032 | } |
fbb9ce95 | 3033 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 3034 | |
3aa416b0 | 3035 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 3036 | return 0; |
381a2292 | 3037 | |
3aa416b0 | 3038 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
3039 | curr->lockdep_depth++; |
3040 | check_chain_key(curr); | |
60e114d1 JP |
3041 | #ifdef CONFIG_DEBUG_LOCKDEP |
3042 | if (unlikely(!debug_locks)) | |
3043 | return 0; | |
3044 | #endif | |
fbb9ce95 IM |
3045 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
3046 | debug_locks_off(); | |
3047 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
3048 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 3049 | dump_stack(); |
fbb9ce95 IM |
3050 | return 0; |
3051 | } | |
381a2292 | 3052 | |
fbb9ce95 IM |
3053 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
3054 | max_lockdep_depth = curr->lockdep_depth; | |
3055 | ||
3056 | return 1; | |
3057 | } | |
3058 | ||
3059 | static int | |
3060 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3061 | unsigned long ip) | |
3062 | { | |
3063 | if (!debug_locks_off()) | |
3064 | return 0; | |
3065 | if (debug_locks_silent) | |
3066 | return 0; | |
3067 | ||
3068 | printk("\n=====================================\n"); | |
3069 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
3070 | printk( "-------------------------------------\n"); | |
3071 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 3072 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3073 | print_lockdep_cache(lock); |
3074 | printk(") at:\n"); | |
3075 | print_ip_sym(ip); | |
3076 | printk("but there are no more locks to release!\n"); | |
3077 | printk("\nother info that might help us debug this:\n"); | |
3078 | lockdep_print_held_locks(curr); | |
3079 | ||
3080 | printk("\nstack backtrace:\n"); | |
3081 | dump_stack(); | |
3082 | ||
3083 | return 0; | |
3084 | } | |
3085 | ||
3086 | /* | |
3087 | * Common debugging checks for both nested and non-nested unlock: | |
3088 | */ | |
3089 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
3090 | unsigned long ip) | |
3091 | { | |
3092 | if (unlikely(!debug_locks)) | |
3093 | return 0; | |
3094 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
3095 | return 0; | |
3096 | ||
3097 | if (curr->lockdep_depth <= 0) | |
3098 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3099 | ||
3100 | return 1; | |
3101 | } | |
3102 | ||
bb97a91e PZ |
3103 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
3104 | { | |
3105 | if (hlock->instance == lock) | |
3106 | return 1; | |
3107 | ||
3108 | if (hlock->references) { | |
62016250 | 3109 | struct lock_class *class = lock->class_cache[0]; |
bb97a91e PZ |
3110 | |
3111 | if (!class) | |
3112 | class = look_up_lock_class(lock, 0); | |
3113 | ||
80e0401e PZ |
3114 | /* |
3115 | * If look_up_lock_class() failed to find a class, we're trying | |
3116 | * to test if we hold a lock that has never yet been acquired. | |
3117 | * Clearly if the lock hasn't been acquired _ever_, we're not | |
3118 | * holding it either, so report failure. | |
3119 | */ | |
3120 | if (!class) | |
bb97a91e PZ |
3121 | return 0; |
3122 | ||
3123 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) | |
3124 | return 0; | |
3125 | ||
3126 | if (hlock->class_idx == class - lock_classes + 1) | |
3127 | return 1; | |
3128 | } | |
3129 | ||
3130 | return 0; | |
3131 | } | |
3132 | ||
64aa348e | 3133 | static int |
00ef9f73 PZ |
3134 | __lock_set_class(struct lockdep_map *lock, const char *name, |
3135 | struct lock_class_key *key, unsigned int subclass, | |
3136 | unsigned long ip) | |
64aa348e PZ |
3137 | { |
3138 | struct task_struct *curr = current; | |
3139 | struct held_lock *hlock, *prev_hlock; | |
3140 | struct lock_class *class; | |
3141 | unsigned int depth; | |
3142 | int i; | |
3143 | ||
3144 | depth = curr->lockdep_depth; | |
3145 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3146 | return 0; | |
3147 | ||
3148 | prev_hlock = NULL; | |
3149 | for (i = depth-1; i >= 0; i--) { | |
3150 | hlock = curr->held_locks + i; | |
3151 | /* | |
3152 | * We must not cross into another context: | |
3153 | */ | |
3154 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3155 | break; | |
bb97a91e | 3156 | if (match_held_lock(hlock, lock)) |
64aa348e PZ |
3157 | goto found_it; |
3158 | prev_hlock = hlock; | |
3159 | } | |
3160 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3161 | ||
3162 | found_it: | |
00ef9f73 | 3163 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 3164 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 3165 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
3166 | |
3167 | curr->lockdep_depth = i; | |
3168 | curr->curr_chain_key = hlock->prev_chain_key; | |
3169 | ||
3170 | for (; i < depth; i++) { | |
3171 | hlock = curr->held_locks + i; | |
3172 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3173 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 3174 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3175 | hlock->nest_lock, hlock->acquire_ip, |
3176 | hlock->references)) | |
64aa348e PZ |
3177 | return 0; |
3178 | } | |
3179 | ||
3180 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
3181 | return 0; | |
3182 | return 1; | |
3183 | } | |
3184 | ||
fbb9ce95 IM |
3185 | /* |
3186 | * Remove the lock to the list of currently held locks in a | |
3187 | * potentially non-nested (out of order) manner. This is a | |
3188 | * relatively rare operation, as all the unlock APIs default | |
3189 | * to nested mode (which uses lock_release()): | |
3190 | */ | |
3191 | static int | |
3192 | lock_release_non_nested(struct task_struct *curr, | |
3193 | struct lockdep_map *lock, unsigned long ip) | |
3194 | { | |
3195 | struct held_lock *hlock, *prev_hlock; | |
3196 | unsigned int depth; | |
3197 | int i; | |
3198 | ||
3199 | /* | |
3200 | * Check whether the lock exists in the current stack | |
3201 | * of held locks: | |
3202 | */ | |
3203 | depth = curr->lockdep_depth; | |
3204 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3205 | return 0; | |
3206 | ||
3207 | prev_hlock = NULL; | |
3208 | for (i = depth-1; i >= 0; i--) { | |
3209 | hlock = curr->held_locks + i; | |
3210 | /* | |
3211 | * We must not cross into another context: | |
3212 | */ | |
3213 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3214 | break; | |
bb97a91e | 3215 | if (match_held_lock(hlock, lock)) |
fbb9ce95 IM |
3216 | goto found_it; |
3217 | prev_hlock = hlock; | |
3218 | } | |
3219 | return print_unlock_inbalance_bug(curr, lock, ip); | |
3220 | ||
3221 | found_it: | |
bb97a91e PZ |
3222 | if (hlock->instance == lock) |
3223 | lock_release_holdtime(hlock); | |
3224 | ||
3225 | if (hlock->references) { | |
3226 | hlock->references--; | |
3227 | if (hlock->references) { | |
3228 | /* | |
3229 | * We had, and after removing one, still have | |
3230 | * references, the current lock stack is still | |
3231 | * valid. We're done! | |
3232 | */ | |
3233 | return 1; | |
3234 | } | |
3235 | } | |
f20786ff | 3236 | |
fbb9ce95 IM |
3237 | /* |
3238 | * We have the right lock to unlock, 'hlock' points to it. | |
3239 | * Now we remove it from the stack, and add back the other | |
3240 | * entries (if any), recalculating the hash along the way: | |
3241 | */ | |
bb97a91e | 3242 | |
fbb9ce95 IM |
3243 | curr->lockdep_depth = i; |
3244 | curr->curr_chain_key = hlock->prev_chain_key; | |
3245 | ||
3246 | for (i++; i < depth; i++) { | |
3247 | hlock = curr->held_locks + i; | |
3248 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 3249 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 3250 | hlock->read, hlock->check, hlock->hardirqs_off, |
bb97a91e PZ |
3251 | hlock->nest_lock, hlock->acquire_ip, |
3252 | hlock->references)) | |
fbb9ce95 IM |
3253 | return 0; |
3254 | } | |
3255 | ||
3256 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
3257 | return 0; | |
3258 | return 1; | |
3259 | } | |
3260 | ||
3261 | /* | |
3262 | * Remove the lock to the list of currently held locks - this gets | |
3263 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3264 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3265 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3266 | */ | |
3267 | static int lock_release_nested(struct task_struct *curr, | |
3268 | struct lockdep_map *lock, unsigned long ip) | |
3269 | { | |
3270 | struct held_lock *hlock; | |
3271 | unsigned int depth; | |
3272 | ||
3273 | /* | |
3274 | * Pop off the top of the lock stack: | |
3275 | */ | |
3276 | depth = curr->lockdep_depth - 1; | |
3277 | hlock = curr->held_locks + depth; | |
3278 | ||
3279 | /* | |
3280 | * Is the unlock non-nested: | |
3281 | */ | |
bb97a91e | 3282 | if (hlock->instance != lock || hlock->references) |
fbb9ce95 IM |
3283 | return lock_release_non_nested(curr, lock, ip); |
3284 | curr->lockdep_depth--; | |
3285 | ||
3286 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
3287 | return 0; | |
3288 | ||
3289 | curr->curr_chain_key = hlock->prev_chain_key; | |
3290 | ||
f20786ff PZ |
3291 | lock_release_holdtime(hlock); |
3292 | ||
fbb9ce95 IM |
3293 | #ifdef CONFIG_DEBUG_LOCKDEP |
3294 | hlock->prev_chain_key = 0; | |
f82b217e | 3295 | hlock->class_idx = 0; |
fbb9ce95 IM |
3296 | hlock->acquire_ip = 0; |
3297 | hlock->irq_context = 0; | |
3298 | #endif | |
3299 | return 1; | |
3300 | } | |
3301 | ||
3302 | /* | |
3303 | * Remove the lock to the list of currently held locks - this gets | |
3304 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
3305 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
3306 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
3307 | */ | |
3308 | static void | |
3309 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
3310 | { | |
3311 | struct task_struct *curr = current; | |
3312 | ||
3313 | if (!check_unlock(curr, lock, ip)) | |
3314 | return; | |
3315 | ||
3316 | if (nested) { | |
3317 | if (!lock_release_nested(curr, lock, ip)) | |
3318 | return; | |
3319 | } else { | |
3320 | if (!lock_release_non_nested(curr, lock, ip)) | |
3321 | return; | |
3322 | } | |
3323 | ||
3324 | check_chain_key(curr); | |
3325 | } | |
3326 | ||
f607c668 PZ |
3327 | static int __lock_is_held(struct lockdep_map *lock) |
3328 | { | |
3329 | struct task_struct *curr = current; | |
3330 | int i; | |
3331 | ||
3332 | for (i = 0; i < curr->lockdep_depth; i++) { | |
bb97a91e PZ |
3333 | struct held_lock *hlock = curr->held_locks + i; |
3334 | ||
3335 | if (match_held_lock(hlock, lock)) | |
f607c668 PZ |
3336 | return 1; |
3337 | } | |
3338 | ||
3339 | return 0; | |
3340 | } | |
3341 | ||
fbb9ce95 IM |
3342 | /* |
3343 | * Check whether we follow the irq-flags state precisely: | |
3344 | */ | |
1d09daa5 | 3345 | static void check_flags(unsigned long flags) |
fbb9ce95 | 3346 | { |
992860e9 IM |
3347 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
3348 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
3349 | if (!debug_locks) |
3350 | return; | |
3351 | ||
5f9fa8a6 IM |
3352 | if (irqs_disabled_flags(flags)) { |
3353 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3354 | printk("possible reason: unannotated irqs-off.\n"); | |
3355 | } | |
3356 | } else { | |
3357 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3358 | printk("possible reason: unannotated irqs-on.\n"); | |
3359 | } | |
3360 | } | |
fbb9ce95 IM |
3361 | |
3362 | /* | |
3363 | * We dont accurately track softirq state in e.g. | |
3364 | * hardirq contexts (such as on 4KSTACKS), so only | |
3365 | * check if not in hardirq contexts: | |
3366 | */ | |
3367 | if (!hardirq_count()) { | |
3368 | if (softirq_count()) | |
3369 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3370 | else | |
3371 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3372 | } | |
3373 | ||
3374 | if (!debug_locks) | |
3375 | print_irqtrace_events(current); | |
3376 | #endif | |
3377 | } | |
3378 | ||
00ef9f73 PZ |
3379 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3380 | struct lock_class_key *key, unsigned int subclass, | |
3381 | unsigned long ip) | |
64aa348e PZ |
3382 | { |
3383 | unsigned long flags; | |
3384 | ||
3385 | if (unlikely(current->lockdep_recursion)) | |
3386 | return; | |
3387 | ||
3388 | raw_local_irq_save(flags); | |
3389 | current->lockdep_recursion = 1; | |
3390 | check_flags(flags); | |
00ef9f73 | 3391 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3392 | check_chain_key(current); |
3393 | current->lockdep_recursion = 0; | |
3394 | raw_local_irq_restore(flags); | |
3395 | } | |
00ef9f73 | 3396 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3397 | |
fbb9ce95 IM |
3398 | /* |
3399 | * We are not always called with irqs disabled - do that here, | |
3400 | * and also avoid lockdep recursion: | |
3401 | */ | |
1d09daa5 | 3402 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3403 | int trylock, int read, int check, |
3404 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3405 | { |
3406 | unsigned long flags; | |
3407 | ||
3408 | if (unlikely(current->lockdep_recursion)) | |
3409 | return; | |
3410 | ||
3411 | raw_local_irq_save(flags); | |
3412 | check_flags(flags); | |
3413 | ||
3414 | current->lockdep_recursion = 1; | |
db2c4c77 | 3415 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
fbb9ce95 | 3416 | __lock_acquire(lock, subclass, trylock, read, check, |
bb97a91e | 3417 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
fbb9ce95 IM |
3418 | current->lockdep_recursion = 0; |
3419 | raw_local_irq_restore(flags); | |
3420 | } | |
fbb9ce95 IM |
3421 | EXPORT_SYMBOL_GPL(lock_acquire); |
3422 | ||
1d09daa5 | 3423 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3424 | unsigned long ip) |
fbb9ce95 IM |
3425 | { |
3426 | unsigned long flags; | |
3427 | ||
3428 | if (unlikely(current->lockdep_recursion)) | |
3429 | return; | |
3430 | ||
3431 | raw_local_irq_save(flags); | |
3432 | check_flags(flags); | |
3433 | current->lockdep_recursion = 1; | |
93135439 | 3434 | trace_lock_release(lock, ip); |
fbb9ce95 IM |
3435 | __lock_release(lock, nested, ip); |
3436 | current->lockdep_recursion = 0; | |
3437 | raw_local_irq_restore(flags); | |
3438 | } | |
fbb9ce95 IM |
3439 | EXPORT_SYMBOL_GPL(lock_release); |
3440 | ||
f607c668 PZ |
3441 | int lock_is_held(struct lockdep_map *lock) |
3442 | { | |
3443 | unsigned long flags; | |
3444 | int ret = 0; | |
3445 | ||
3446 | if (unlikely(current->lockdep_recursion)) | |
f2513cde | 3447 | return 1; /* avoid false negative lockdep_assert_held() */ |
f607c668 PZ |
3448 | |
3449 | raw_local_irq_save(flags); | |
3450 | check_flags(flags); | |
3451 | ||
3452 | current->lockdep_recursion = 1; | |
3453 | ret = __lock_is_held(lock); | |
3454 | current->lockdep_recursion = 0; | |
3455 | raw_local_irq_restore(flags); | |
3456 | ||
3457 | return ret; | |
3458 | } | |
3459 | EXPORT_SYMBOL_GPL(lock_is_held); | |
3460 | ||
cf40bd16 NP |
3461 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3462 | { | |
3463 | current->lockdep_reclaim_gfp = gfp_mask; | |
3464 | } | |
3465 | ||
3466 | void lockdep_clear_current_reclaim_state(void) | |
3467 | { | |
3468 | current->lockdep_reclaim_gfp = 0; | |
3469 | } | |
3470 | ||
f20786ff PZ |
3471 | #ifdef CONFIG_LOCK_STAT |
3472 | static int | |
3473 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3474 | unsigned long ip) | |
3475 | { | |
3476 | if (!debug_locks_off()) | |
3477 | return 0; | |
3478 | if (debug_locks_silent) | |
3479 | return 0; | |
3480 | ||
3481 | printk("\n=================================\n"); | |
3482 | printk( "[ BUG: bad contention detected! ]\n"); | |
3483 | printk( "---------------------------------\n"); | |
3484 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3485 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3486 | print_lockdep_cache(lock); |
3487 | printk(") at:\n"); | |
3488 | print_ip_sym(ip); | |
3489 | printk("but there are no locks held!\n"); | |
3490 | printk("\nother info that might help us debug this:\n"); | |
3491 | lockdep_print_held_locks(curr); | |
3492 | ||
3493 | printk("\nstack backtrace:\n"); | |
3494 | dump_stack(); | |
3495 | ||
3496 | return 0; | |
3497 | } | |
3498 | ||
3499 | static void | |
3500 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3501 | { | |
3502 | struct task_struct *curr = current; | |
3503 | struct held_lock *hlock, *prev_hlock; | |
3504 | struct lock_class_stats *stats; | |
3505 | unsigned int depth; | |
c7e78cff | 3506 | int i, contention_point, contending_point; |
f20786ff PZ |
3507 | |
3508 | depth = curr->lockdep_depth; | |
3509 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3510 | return; | |
3511 | ||
3512 | prev_hlock = NULL; | |
3513 | for (i = depth-1; i >= 0; i--) { | |
3514 | hlock = curr->held_locks + i; | |
3515 | /* | |
3516 | * We must not cross into another context: | |
3517 | */ | |
3518 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3519 | break; | |
bb97a91e | 3520 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3521 | goto found_it; |
3522 | prev_hlock = hlock; | |
3523 | } | |
3524 | print_lock_contention_bug(curr, lock, ip); | |
3525 | return; | |
3526 | ||
3527 | found_it: | |
bb97a91e PZ |
3528 | if (hlock->instance != lock) |
3529 | return; | |
3530 | ||
3365e779 | 3531 | hlock->waittime_stamp = lockstat_clock(); |
f20786ff | 3532 | |
c7e78cff PZ |
3533 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3534 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3535 | lock->ip); | |
f20786ff | 3536 | |
f82b217e | 3537 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3538 | if (contention_point < LOCKSTAT_POINTS) |
3539 | stats->contention_point[contention_point]++; | |
3540 | if (contending_point < LOCKSTAT_POINTS) | |
3541 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3542 | if (lock->cpu != smp_processor_id()) |
3543 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3544 | put_lock_stats(stats); |
3545 | } | |
3546 | ||
3547 | static void | |
c7e78cff | 3548 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3549 | { |
3550 | struct task_struct *curr = current; | |
3551 | struct held_lock *hlock, *prev_hlock; | |
3552 | struct lock_class_stats *stats; | |
3553 | unsigned int depth; | |
3365e779 | 3554 | u64 now, waittime = 0; |
96645678 | 3555 | int i, cpu; |
f20786ff PZ |
3556 | |
3557 | depth = curr->lockdep_depth; | |
3558 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3559 | return; | |
3560 | ||
3561 | prev_hlock = NULL; | |
3562 | for (i = depth-1; i >= 0; i--) { | |
3563 | hlock = curr->held_locks + i; | |
3564 | /* | |
3565 | * We must not cross into another context: | |
3566 | */ | |
3567 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3568 | break; | |
bb97a91e | 3569 | if (match_held_lock(hlock, lock)) |
f20786ff PZ |
3570 | goto found_it; |
3571 | prev_hlock = hlock; | |
3572 | } | |
3573 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3574 | return; | |
3575 | ||
3576 | found_it: | |
bb97a91e PZ |
3577 | if (hlock->instance != lock) |
3578 | return; | |
3579 | ||
96645678 PZ |
3580 | cpu = smp_processor_id(); |
3581 | if (hlock->waittime_stamp) { | |
3365e779 | 3582 | now = lockstat_clock(); |
96645678 PZ |
3583 | waittime = now - hlock->waittime_stamp; |
3584 | hlock->holdtime_stamp = now; | |
3585 | } | |
f20786ff | 3586 | |
883a2a31 | 3587 | trace_lock_acquired(lock, ip); |
2062501a | 3588 | |
f82b217e | 3589 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3590 | if (waittime) { |
3591 | if (hlock->read) | |
3592 | lock_time_inc(&stats->read_waittime, waittime); | |
3593 | else | |
3594 | lock_time_inc(&stats->write_waittime, waittime); | |
3595 | } | |
3596 | if (lock->cpu != cpu) | |
3597 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3598 | put_lock_stats(stats); |
96645678 PZ |
3599 | |
3600 | lock->cpu = cpu; | |
c7e78cff | 3601 | lock->ip = ip; |
f20786ff PZ |
3602 | } |
3603 | ||
3604 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3605 | { | |
3606 | unsigned long flags; | |
3607 | ||
3608 | if (unlikely(!lock_stat)) | |
3609 | return; | |
3610 | ||
3611 | if (unlikely(current->lockdep_recursion)) | |
3612 | return; | |
3613 | ||
3614 | raw_local_irq_save(flags); | |
3615 | check_flags(flags); | |
3616 | current->lockdep_recursion = 1; | |
db2c4c77 | 3617 | trace_lock_contended(lock, ip); |
f20786ff PZ |
3618 | __lock_contended(lock, ip); |
3619 | current->lockdep_recursion = 0; | |
3620 | raw_local_irq_restore(flags); | |
3621 | } | |
3622 | EXPORT_SYMBOL_GPL(lock_contended); | |
3623 | ||
c7e78cff | 3624 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3625 | { |
3626 | unsigned long flags; | |
3627 | ||
3628 | if (unlikely(!lock_stat)) | |
3629 | return; | |
3630 | ||
3631 | if (unlikely(current->lockdep_recursion)) | |
3632 | return; | |
3633 | ||
3634 | raw_local_irq_save(flags); | |
3635 | check_flags(flags); | |
3636 | current->lockdep_recursion = 1; | |
c7e78cff | 3637 | __lock_acquired(lock, ip); |
f20786ff PZ |
3638 | current->lockdep_recursion = 0; |
3639 | raw_local_irq_restore(flags); | |
3640 | } | |
3641 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3642 | #endif | |
3643 | ||
fbb9ce95 IM |
3644 | /* |
3645 | * Used by the testsuite, sanitize the validator state | |
3646 | * after a simulated failure: | |
3647 | */ | |
3648 | ||
3649 | void lockdep_reset(void) | |
3650 | { | |
3651 | unsigned long flags; | |
23d95a03 | 3652 | int i; |
fbb9ce95 IM |
3653 | |
3654 | raw_local_irq_save(flags); | |
3655 | current->curr_chain_key = 0; | |
3656 | current->lockdep_depth = 0; | |
3657 | current->lockdep_recursion = 0; | |
3658 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3659 | nr_hardirq_chains = 0; | |
3660 | nr_softirq_chains = 0; | |
3661 | nr_process_chains = 0; | |
3662 | debug_locks = 1; | |
23d95a03 IM |
3663 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3664 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3665 | raw_local_irq_restore(flags); |
3666 | } | |
3667 | ||
3668 | static void zap_class(struct lock_class *class) | |
3669 | { | |
3670 | int i; | |
3671 | ||
3672 | /* | |
3673 | * Remove all dependencies this lock is | |
3674 | * involved in: | |
3675 | */ | |
3676 | for (i = 0; i < nr_list_entries; i++) { | |
3677 | if (list_entries[i].class == class) | |
3678 | list_del_rcu(&list_entries[i].entry); | |
3679 | } | |
3680 | /* | |
3681 | * Unhash the class and remove it from the all_lock_classes list: | |
3682 | */ | |
3683 | list_del_rcu(&class->hash_entry); | |
3684 | list_del_rcu(&class->lock_entry); | |
3685 | ||
8bfe0298 | 3686 | class->key = NULL; |
fbb9ce95 IM |
3687 | } |
3688 | ||
fabe874a | 3689 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3690 | { |
3691 | return addr >= start && addr < start + size; | |
3692 | } | |
3693 | ||
3694 | void lockdep_free_key_range(void *start, unsigned long size) | |
3695 | { | |
3696 | struct lock_class *class, *next; | |
3697 | struct list_head *head; | |
3698 | unsigned long flags; | |
3699 | int i; | |
5a26db5b | 3700 | int locked; |
fbb9ce95 IM |
3701 | |
3702 | raw_local_irq_save(flags); | |
5a26db5b | 3703 | locked = graph_lock(); |
fbb9ce95 IM |
3704 | |
3705 | /* | |
3706 | * Unhash all classes that were created by this module: | |
3707 | */ | |
3708 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3709 | head = classhash_table + i; | |
3710 | if (list_empty(head)) | |
3711 | continue; | |
fabe874a | 3712 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3713 | if (within(class->key, start, size)) |
3714 | zap_class(class); | |
fabe874a AV |
3715 | else if (within(class->name, start, size)) |
3716 | zap_class(class); | |
3717 | } | |
fbb9ce95 IM |
3718 | } |
3719 | ||
5a26db5b NP |
3720 | if (locked) |
3721 | graph_unlock(); | |
fbb9ce95 IM |
3722 | raw_local_irq_restore(flags); |
3723 | } | |
3724 | ||
3725 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3726 | { | |
d6d897ce | 3727 | struct lock_class *class, *next; |
fbb9ce95 IM |
3728 | struct list_head *head; |
3729 | unsigned long flags; | |
3730 | int i, j; | |
5a26db5b | 3731 | int locked; |
fbb9ce95 IM |
3732 | |
3733 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3734 | |
3735 | /* | |
d6d897ce IM |
3736 | * Remove all classes this lock might have: |
3737 | */ | |
3738 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3739 | /* | |
3740 | * If the class exists we look it up and zap it: | |
3741 | */ | |
3742 | class = look_up_lock_class(lock, j); | |
3743 | if (class) | |
3744 | zap_class(class); | |
3745 | } | |
3746 | /* | |
3747 | * Debug check: in the end all mapped classes should | |
3748 | * be gone. | |
fbb9ce95 | 3749 | */ |
5a26db5b | 3750 | locked = graph_lock(); |
fbb9ce95 IM |
3751 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3752 | head = classhash_table + i; | |
3753 | if (list_empty(head)) | |
3754 | continue; | |
3755 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
62016250 HM |
3756 | int match = 0; |
3757 | ||
3758 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) | |
3759 | match |= class == lock->class_cache[j]; | |
3760 | ||
3761 | if (unlikely(match)) { | |
74c383f1 IM |
3762 | if (debug_locks_off_graph_unlock()) |
3763 | WARN_ON(1); | |
d6d897ce | 3764 | goto out_restore; |
fbb9ce95 IM |
3765 | } |
3766 | } | |
3767 | } | |
5a26db5b NP |
3768 | if (locked) |
3769 | graph_unlock(); | |
d6d897ce IM |
3770 | |
3771 | out_restore: | |
fbb9ce95 IM |
3772 | raw_local_irq_restore(flags); |
3773 | } | |
3774 | ||
1499993c | 3775 | void lockdep_init(void) |
fbb9ce95 IM |
3776 | { |
3777 | int i; | |
3778 | ||
3779 | /* | |
3780 | * Some architectures have their own start_kernel() | |
3781 | * code which calls lockdep_init(), while we also | |
3782 | * call lockdep_init() from the start_kernel() itself, | |
3783 | * and we want to initialize the hashes only once: | |
3784 | */ | |
3785 | if (lockdep_initialized) | |
3786 | return; | |
3787 | ||
3788 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3789 | INIT_LIST_HEAD(classhash_table + i); | |
3790 | ||
3791 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3792 | INIT_LIST_HEAD(chainhash_table + i); | |
3793 | ||
3794 | lockdep_initialized = 1; | |
3795 | } | |
3796 | ||
3797 | void __init lockdep_info(void) | |
3798 | { | |
3799 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3800 | ||
b0788caf | 3801 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3802 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3803 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3804 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3805 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3806 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3807 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3808 | ||
3809 | printk(" memory used by lock dependency info: %lu kB\n", | |
3810 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3811 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3812 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3813 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
90629209 | 3814 | sizeof(struct list_head) * CHAINHASH_SIZE |
4dd861d6 | 3815 | #ifdef CONFIG_PROVE_LOCKING |
e351b660 | 3816 | + sizeof(struct circular_queue) |
4dd861d6 | 3817 | #endif |
90629209 | 3818 | ) / 1024 |
4dd861d6 | 3819 | ); |
fbb9ce95 IM |
3820 | |
3821 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3822 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3823 | ||
3824 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3825 | if (lockdep_init_error) { |
3826 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3827 | printk("Call stack leading to lockdep invocation was:\n"); | |
3828 | print_stack_trace(&lockdep_init_trace, 0); | |
3829 | } | |
fbb9ce95 IM |
3830 | #endif |
3831 | } | |
3832 | ||
fbb9ce95 IM |
3833 | static void |
3834 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3835 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3836 | { |
3837 | if (!debug_locks_off()) | |
3838 | return; | |
3839 | if (debug_locks_silent) | |
3840 | return; | |
3841 | ||
3842 | printk("\n=========================\n"); | |
3843 | printk( "[ BUG: held lock freed! ]\n"); | |
3844 | printk( "-------------------------\n"); | |
3845 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3846 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3847 | print_lock(hlock); |
fbb9ce95 IM |
3848 | lockdep_print_held_locks(curr); |
3849 | ||
3850 | printk("\nstack backtrace:\n"); | |
3851 | dump_stack(); | |
3852 | } | |
3853 | ||
54561783 ON |
3854 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3855 | const void* lock_from, unsigned long lock_len) | |
3856 | { | |
3857 | return lock_from + lock_len <= mem_from || | |
3858 | mem_from + mem_len <= lock_from; | |
3859 | } | |
3860 | ||
fbb9ce95 IM |
3861 | /* |
3862 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3863 | * is destroyed or reinitialized - this code checks whether there is | |
3864 | * any held lock in the memory range of <from> to <to>: | |
3865 | */ | |
3866 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3867 | { | |
fbb9ce95 IM |
3868 | struct task_struct *curr = current; |
3869 | struct held_lock *hlock; | |
3870 | unsigned long flags; | |
3871 | int i; | |
3872 | ||
3873 | if (unlikely(!debug_locks)) | |
3874 | return; | |
3875 | ||
3876 | local_irq_save(flags); | |
3877 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3878 | hlock = curr->held_locks + i; | |
3879 | ||
54561783 ON |
3880 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3881 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3882 | continue; |
3883 | ||
54561783 | 3884 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3885 | break; |
3886 | } | |
3887 | local_irq_restore(flags); | |
3888 | } | |
ed07536e | 3889 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3890 | |
3891 | static void print_held_locks_bug(struct task_struct *curr) | |
3892 | { | |
3893 | if (!debug_locks_off()) | |
3894 | return; | |
3895 | if (debug_locks_silent) | |
3896 | return; | |
3897 | ||
3898 | printk("\n=====================================\n"); | |
3899 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3900 | printk( "-------------------------------------\n"); | |
3901 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3902 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3903 | lockdep_print_held_locks(curr); |
3904 | ||
3905 | printk("\nstack backtrace:\n"); | |
3906 | dump_stack(); | |
3907 | } | |
3908 | ||
3909 | void debug_check_no_locks_held(struct task_struct *task) | |
3910 | { | |
3911 | if (unlikely(task->lockdep_depth > 0)) | |
3912 | print_held_locks_bug(task); | |
3913 | } | |
3914 | ||
3915 | void debug_show_all_locks(void) | |
3916 | { | |
3917 | struct task_struct *g, *p; | |
3918 | int count = 10; | |
3919 | int unlock = 1; | |
3920 | ||
9c35dd7f JP |
3921 | if (unlikely(!debug_locks)) { |
3922 | printk("INFO: lockdep is turned off.\n"); | |
3923 | return; | |
3924 | } | |
fbb9ce95 IM |
3925 | printk("\nShowing all locks held in the system:\n"); |
3926 | ||
3927 | /* | |
3928 | * Here we try to get the tasklist_lock as hard as possible, | |
3929 | * if not successful after 2 seconds we ignore it (but keep | |
3930 | * trying). This is to enable a debug printout even if a | |
3931 | * tasklist_lock-holding task deadlocks or crashes. | |
3932 | */ | |
3933 | retry: | |
3934 | if (!read_trylock(&tasklist_lock)) { | |
3935 | if (count == 10) | |
3936 | printk("hm, tasklist_lock locked, retrying... "); | |
3937 | if (count) { | |
3938 | count--; | |
3939 | printk(" #%d", 10-count); | |
3940 | mdelay(200); | |
3941 | goto retry; | |
3942 | } | |
3943 | printk(" ignoring it.\n"); | |
3944 | unlock = 0; | |
46fec7ac | 3945 | } else { |
3946 | if (count != 10) | |
3947 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3948 | } |
fbb9ce95 IM |
3949 | |
3950 | do_each_thread(g, p) { | |
85684873 IM |
3951 | /* |
3952 | * It's not reliable to print a task's held locks | |
3953 | * if it's not sleeping (or if it's not the current | |
3954 | * task): | |
3955 | */ | |
3956 | if (p->state == TASK_RUNNING && p != current) | |
3957 | continue; | |
fbb9ce95 IM |
3958 | if (p->lockdep_depth) |
3959 | lockdep_print_held_locks(p); | |
3960 | if (!unlock) | |
3961 | if (read_trylock(&tasklist_lock)) | |
3962 | unlock = 1; | |
3963 | } while_each_thread(g, p); | |
3964 | ||
3965 | printk("\n"); | |
3966 | printk("=============================================\n\n"); | |
3967 | ||
3968 | if (unlock) | |
3969 | read_unlock(&tasklist_lock); | |
3970 | } | |
fbb9ce95 IM |
3971 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3972 | ||
82a1fcb9 IM |
3973 | /* |
3974 | * Careful: only use this function if you are sure that | |
3975 | * the task cannot run in parallel! | |
3976 | */ | |
f1b499f0 | 3977 | void debug_show_held_locks(struct task_struct *task) |
fbb9ce95 | 3978 | { |
9c35dd7f JP |
3979 | if (unlikely(!debug_locks)) { |
3980 | printk("INFO: lockdep is turned off.\n"); | |
3981 | return; | |
3982 | } | |
fbb9ce95 IM |
3983 | lockdep_print_held_locks(task); |
3984 | } | |
fbb9ce95 | 3985 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3986 | |
3987 | void lockdep_sys_exit(void) | |
3988 | { | |
3989 | struct task_struct *curr = current; | |
3990 | ||
3991 | if (unlikely(curr->lockdep_depth)) { | |
3992 | if (!debug_locks_off()) | |
3993 | return; | |
3994 | printk("\n================================================\n"); | |
3995 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3996 | printk( "------------------------------------------------\n"); | |
3997 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3998 | curr->comm, curr->pid); | |
3999 | lockdep_print_held_locks(curr); | |
4000 | } | |
4001 | } | |
0632eb3d PM |
4002 | |
4003 | void lockdep_rcu_dereference(const char *file, const int line) | |
4004 | { | |
4005 | struct task_struct *curr = current; | |
4006 | ||
2b3fc35f | 4007 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
0632eb3d PM |
4008 | if (!debug_locks_off()) |
4009 | return; | |
2b3fc35f LJ |
4010 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
4011 | /* Note: the following can be executed concurrently, so be careful. */ | |
056ba4a9 PM |
4012 | printk("\n===================================================\n"); |
4013 | printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n"); | |
4014 | printk( "---------------------------------------------------\n"); | |
0632eb3d PM |
4015 | printk("%s:%d invoked rcu_dereference_check() without protection!\n", |
4016 | file, line); | |
4017 | printk("\nother info that might help us debug this:\n\n"); | |
cc5b83a9 | 4018 | printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks); |
0632eb3d PM |
4019 | lockdep_print_held_locks(curr); |
4020 | printk("\nstack backtrace:\n"); | |
4021 | dump_stack(); | |
4022 | } | |
4023 | EXPORT_SYMBOL_GPL(lockdep_rcu_dereference); |