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Commit | Line | Data |
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fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
fbb9ce95 IM |
46 | #include <asm/sections.h> |
47 | ||
48 | #include "lockdep_internals.h" | |
49 | ||
a8d154b0 | 50 | #define CREATE_TRACE_POINTS |
ad8d75ff | 51 | #include <trace/events/lockdep.h> |
a8d154b0 | 52 | |
f20786ff PZ |
53 | #ifdef CONFIG_PROVE_LOCKING |
54 | int prove_locking = 1; | |
55 | module_param(prove_locking, int, 0644); | |
56 | #else | |
57 | #define prove_locking 0 | |
58 | #endif | |
59 | ||
60 | #ifdef CONFIG_LOCK_STAT | |
61 | int lock_stat = 1; | |
62 | module_param(lock_stat, int, 0644); | |
63 | #else | |
64 | #define lock_stat 0 | |
65 | #endif | |
66 | ||
fbb9ce95 | 67 | /* |
74c383f1 IM |
68 | * lockdep_lock: protects the lockdep graph, the hashes and the |
69 | * class/list/hash allocators. | |
fbb9ce95 IM |
70 | * |
71 | * This is one of the rare exceptions where it's justified | |
72 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 73 | * code to recurse back into the lockdep code... |
fbb9ce95 | 74 | */ |
74c383f1 IM |
75 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
76 | ||
77 | static int graph_lock(void) | |
78 | { | |
79 | __raw_spin_lock(&lockdep_lock); | |
80 | /* | |
81 | * Make sure that if another CPU detected a bug while | |
82 | * walking the graph we dont change it (while the other | |
83 | * CPU is busy printing out stuff with the graph lock | |
84 | * dropped already) | |
85 | */ | |
86 | if (!debug_locks) { | |
87 | __raw_spin_unlock(&lockdep_lock); | |
88 | return 0; | |
89 | } | |
bb065afb SR |
90 | /* prevent any recursions within lockdep from causing deadlocks */ |
91 | current->lockdep_recursion++; | |
74c383f1 IM |
92 | return 1; |
93 | } | |
94 | ||
95 | static inline int graph_unlock(void) | |
96 | { | |
381a2292 JP |
97 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
98 | return DEBUG_LOCKS_WARN_ON(1); | |
99 | ||
bb065afb | 100 | current->lockdep_recursion--; |
74c383f1 IM |
101 | __raw_spin_unlock(&lockdep_lock); |
102 | return 0; | |
103 | } | |
104 | ||
105 | /* | |
106 | * Turn lock debugging off and return with 0 if it was off already, | |
107 | * and also release the graph lock: | |
108 | */ | |
109 | static inline int debug_locks_off_graph_unlock(void) | |
110 | { | |
111 | int ret = debug_locks_off(); | |
112 | ||
113 | __raw_spin_unlock(&lockdep_lock); | |
114 | ||
115 | return ret; | |
116 | } | |
fbb9ce95 IM |
117 | |
118 | static int lockdep_initialized; | |
119 | ||
120 | unsigned long nr_list_entries; | |
d588e461 | 121 | struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 122 | |
fbb9ce95 IM |
123 | /* |
124 | * All data structures here are protected by the global debug_lock. | |
125 | * | |
126 | * Mutex key structs only get allocated, once during bootup, and never | |
127 | * get freed - this significantly simplifies the debugging code. | |
128 | */ | |
129 | unsigned long nr_lock_classes; | |
130 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
131 | ||
f82b217e DJ |
132 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
133 | { | |
134 | if (!hlock->class_idx) { | |
135 | DEBUG_LOCKS_WARN_ON(1); | |
136 | return NULL; | |
137 | } | |
138 | return lock_classes + hlock->class_idx - 1; | |
139 | } | |
140 | ||
f20786ff PZ |
141 | #ifdef CONFIG_LOCK_STAT |
142 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); | |
143 | ||
c7e78cff | 144 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
145 | { |
146 | int i; | |
147 | ||
c7e78cff PZ |
148 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
149 | if (points[i] == 0) { | |
150 | points[i] = ip; | |
f20786ff PZ |
151 | break; |
152 | } | |
c7e78cff | 153 | if (points[i] == ip) |
f20786ff PZ |
154 | break; |
155 | } | |
156 | ||
157 | return i; | |
158 | } | |
159 | ||
160 | static void lock_time_inc(struct lock_time *lt, s64 time) | |
161 | { | |
162 | if (time > lt->max) | |
163 | lt->max = time; | |
164 | ||
165 | if (time < lt->min || !lt->min) | |
166 | lt->min = time; | |
167 | ||
168 | lt->total += time; | |
169 | lt->nr++; | |
170 | } | |
171 | ||
c46261de PZ |
172 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
173 | { | |
174 | dst->min += src->min; | |
175 | dst->max += src->max; | |
176 | dst->total += src->total; | |
177 | dst->nr += src->nr; | |
178 | } | |
179 | ||
180 | struct lock_class_stats lock_stats(struct lock_class *class) | |
181 | { | |
182 | struct lock_class_stats stats; | |
183 | int cpu, i; | |
184 | ||
185 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
186 | for_each_possible_cpu(cpu) { | |
187 | struct lock_class_stats *pcs = | |
188 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
189 | ||
190 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
191 | stats.contention_point[i] += pcs->contention_point[i]; | |
192 | ||
c7e78cff PZ |
193 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
194 | stats.contending_point[i] += pcs->contending_point[i]; | |
195 | ||
c46261de PZ |
196 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
197 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
198 | ||
199 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
200 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
201 | |
202 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
203 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
204 | } |
205 | ||
206 | return stats; | |
207 | } | |
208 | ||
209 | void clear_lock_stats(struct lock_class *class) | |
210 | { | |
211 | int cpu; | |
212 | ||
213 | for_each_possible_cpu(cpu) { | |
214 | struct lock_class_stats *cpu_stats = | |
215 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
216 | ||
217 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
218 | } | |
219 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 220 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
221 | } |
222 | ||
f20786ff PZ |
223 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
224 | { | |
225 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
226 | } | |
227 | ||
228 | static void put_lock_stats(struct lock_class_stats *stats) | |
229 | { | |
230 | put_cpu_var(lock_stats); | |
231 | } | |
232 | ||
233 | static void lock_release_holdtime(struct held_lock *hlock) | |
234 | { | |
235 | struct lock_class_stats *stats; | |
236 | s64 holdtime; | |
237 | ||
238 | if (!lock_stat) | |
239 | return; | |
240 | ||
241 | holdtime = sched_clock() - hlock->holdtime_stamp; | |
242 | ||
f82b217e | 243 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
244 | if (hlock->read) |
245 | lock_time_inc(&stats->read_holdtime, holdtime); | |
246 | else | |
247 | lock_time_inc(&stats->write_holdtime, holdtime); | |
248 | put_lock_stats(stats); | |
249 | } | |
250 | #else | |
251 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
252 | { | |
253 | } | |
254 | #endif | |
255 | ||
fbb9ce95 IM |
256 | /* |
257 | * We keep a global list of all lock classes. The list only grows, | |
258 | * never shrinks. The list is only accessed with the lockdep | |
259 | * spinlock lock held. | |
260 | */ | |
261 | LIST_HEAD(all_lock_classes); | |
262 | ||
263 | /* | |
264 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
265 | */ | |
266 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
267 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 268 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
269 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
270 | ||
271 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
272 | ||
fbb9ce95 IM |
273 | /* |
274 | * We put the lock dependency chains into a hash-table as well, to cache | |
275 | * their existence: | |
276 | */ | |
277 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
278 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 279 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
280 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
281 | ||
282 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
283 | ||
284 | /* | |
285 | * The hash key of the lock dependency chains is a hash itself too: | |
286 | * it's a hash of all locks taken up to that lock, including that lock. | |
287 | * It's a 64-bit hash, because it's important for the keys to be | |
288 | * unique. | |
289 | */ | |
290 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
291 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
292 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
293 | (key2)) |
294 | ||
1d09daa5 | 295 | void lockdep_off(void) |
fbb9ce95 IM |
296 | { |
297 | current->lockdep_recursion++; | |
298 | } | |
fbb9ce95 IM |
299 | EXPORT_SYMBOL(lockdep_off); |
300 | ||
1d09daa5 | 301 | void lockdep_on(void) |
fbb9ce95 IM |
302 | { |
303 | current->lockdep_recursion--; | |
304 | } | |
fbb9ce95 IM |
305 | EXPORT_SYMBOL(lockdep_on); |
306 | ||
fbb9ce95 IM |
307 | /* |
308 | * Debugging switches: | |
309 | */ | |
310 | ||
311 | #define VERBOSE 0 | |
33e94e96 | 312 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
313 | |
314 | #if VERBOSE | |
315 | # define HARDIRQ_VERBOSE 1 | |
316 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 317 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
318 | #else |
319 | # define HARDIRQ_VERBOSE 0 | |
320 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 321 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
322 | #endif |
323 | ||
cf40bd16 | 324 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
325 | /* |
326 | * Quick filtering for interesting events: | |
327 | */ | |
328 | static int class_filter(struct lock_class *class) | |
329 | { | |
f9829cce AK |
330 | #if 0 |
331 | /* Example */ | |
fbb9ce95 | 332 | if (class->name_version == 1 && |
f9829cce | 333 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
334 | return 1; |
335 | if (class->name_version == 1 && | |
f9829cce | 336 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 337 | return 1; |
f9829cce | 338 | #endif |
a6640897 IM |
339 | /* Filter everything else. 1 would be to allow everything else */ |
340 | return 0; | |
fbb9ce95 IM |
341 | } |
342 | #endif | |
343 | ||
344 | static int verbose(struct lock_class *class) | |
345 | { | |
346 | #if VERBOSE | |
347 | return class_filter(class); | |
348 | #endif | |
349 | return 0; | |
350 | } | |
351 | ||
fbb9ce95 IM |
352 | /* |
353 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 354 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
355 | */ |
356 | unsigned long nr_stack_trace_entries; | |
357 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
358 | ||
359 | static int save_trace(struct stack_trace *trace) | |
360 | { | |
361 | trace->nr_entries = 0; | |
362 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
363 | trace->entries = stack_trace + nr_stack_trace_entries; | |
364 | ||
5a1b3999 | 365 | trace->skip = 3; |
5a1b3999 | 366 | |
ab1b6f03 | 367 | save_stack_trace(trace); |
fbb9ce95 IM |
368 | |
369 | trace->max_entries = trace->nr_entries; | |
370 | ||
371 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
372 | |
373 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
374 | if (!debug_locks_off_graph_unlock()) |
375 | return 0; | |
376 | ||
377 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
378 | printk("turning off the locking correctness validator.\n"); | |
379 | dump_stack(); | |
380 | ||
fbb9ce95 IM |
381 | return 0; |
382 | } | |
383 | ||
384 | return 1; | |
385 | } | |
386 | ||
387 | unsigned int nr_hardirq_chains; | |
388 | unsigned int nr_softirq_chains; | |
389 | unsigned int nr_process_chains; | |
390 | unsigned int max_lockdep_depth; | |
391 | unsigned int max_recursion_depth; | |
392 | ||
419ca3f1 DM |
393 | static unsigned int lockdep_dependency_gen_id; |
394 | ||
395 | static bool lockdep_dependency_visit(struct lock_class *source, | |
396 | unsigned int depth) | |
397 | { | |
398 | if (!depth) | |
399 | lockdep_dependency_gen_id++; | |
400 | if (source->dep_gen_id == lockdep_dependency_gen_id) | |
401 | return true; | |
402 | source->dep_gen_id = lockdep_dependency_gen_id; | |
403 | return false; | |
404 | } | |
405 | ||
fbb9ce95 IM |
406 | #ifdef CONFIG_DEBUG_LOCKDEP |
407 | /* | |
408 | * We cannot printk in early bootup code. Not even early_printk() | |
409 | * might work. So we mark any initialization errors and printk | |
410 | * about it later on, in lockdep_info(). | |
411 | */ | |
412 | static int lockdep_init_error; | |
c71063c9 JB |
413 | static unsigned long lockdep_init_trace_data[20]; |
414 | static struct stack_trace lockdep_init_trace = { | |
415 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
416 | .entries = lockdep_init_trace_data, | |
417 | }; | |
fbb9ce95 IM |
418 | |
419 | /* | |
420 | * Various lockdep statistics: | |
421 | */ | |
422 | atomic_t chain_lookup_hits; | |
423 | atomic_t chain_lookup_misses; | |
424 | atomic_t hardirqs_on_events; | |
425 | atomic_t hardirqs_off_events; | |
426 | atomic_t redundant_hardirqs_on; | |
427 | atomic_t redundant_hardirqs_off; | |
428 | atomic_t softirqs_on_events; | |
429 | atomic_t softirqs_off_events; | |
430 | atomic_t redundant_softirqs_on; | |
431 | atomic_t redundant_softirqs_off; | |
432 | atomic_t nr_unused_locks; | |
433 | atomic_t nr_cyclic_checks; | |
434 | atomic_t nr_cyclic_check_recursions; | |
435 | atomic_t nr_find_usage_forwards_checks; | |
436 | atomic_t nr_find_usage_forwards_recursions; | |
437 | atomic_t nr_find_usage_backwards_checks; | |
438 | atomic_t nr_find_usage_backwards_recursions; | |
fbb9ce95 IM |
439 | #endif |
440 | ||
441 | /* | |
442 | * Locking printouts: | |
443 | */ | |
444 | ||
fabe9c42 | 445 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
446 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
447 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
448 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
449 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 450 | |
fbb9ce95 IM |
451 | static const char *usage_str[] = |
452 | { | |
fabe9c42 PZ |
453 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
454 | #include "lockdep_states.h" | |
455 | #undef LOCKDEP_STATE | |
456 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
457 | }; |
458 | ||
459 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
460 | { | |
ffb45122 | 461 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
462 | } |
463 | ||
3ff176ca | 464 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 465 | { |
3ff176ca PZ |
466 | return 1UL << bit; |
467 | } | |
fbb9ce95 | 468 | |
3ff176ca PZ |
469 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
470 | { | |
471 | char c = '.'; | |
472 | ||
473 | if (class->usage_mask & lock_flag(bit + 2)) | |
474 | c = '+'; | |
475 | if (class->usage_mask & lock_flag(bit)) { | |
476 | c = '-'; | |
477 | if (class->usage_mask & lock_flag(bit + 2)) | |
478 | c = '?'; | |
fbb9ce95 IM |
479 | } |
480 | ||
3ff176ca PZ |
481 | return c; |
482 | } | |
cf40bd16 | 483 | |
f510b233 | 484 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 485 | { |
f510b233 | 486 | int i = 0; |
cf40bd16 | 487 | |
f510b233 PZ |
488 | #define LOCKDEP_STATE(__STATE) \ |
489 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
490 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
491 | #include "lockdep_states.h" | |
492 | #undef LOCKDEP_STATE | |
493 | ||
494 | usage[i] = '\0'; | |
fbb9ce95 IM |
495 | } |
496 | ||
497 | static void print_lock_name(struct lock_class *class) | |
498 | { | |
f510b233 | 499 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
500 | const char *name; |
501 | ||
f510b233 | 502 | get_usage_chars(class, usage); |
fbb9ce95 IM |
503 | |
504 | name = class->name; | |
505 | if (!name) { | |
506 | name = __get_key_name(class->key, str); | |
507 | printk(" (%s", name); | |
508 | } else { | |
509 | printk(" (%s", name); | |
510 | if (class->name_version > 1) | |
511 | printk("#%d", class->name_version); | |
512 | if (class->subclass) | |
513 | printk("/%d", class->subclass); | |
514 | } | |
f510b233 | 515 | printk("){%s}", usage); |
fbb9ce95 IM |
516 | } |
517 | ||
518 | static void print_lockdep_cache(struct lockdep_map *lock) | |
519 | { | |
520 | const char *name; | |
9281acea | 521 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
522 | |
523 | name = lock->name; | |
524 | if (!name) | |
525 | name = __get_key_name(lock->key->subkeys, str); | |
526 | ||
527 | printk("%s", name); | |
528 | } | |
529 | ||
530 | static void print_lock(struct held_lock *hlock) | |
531 | { | |
f82b217e | 532 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
533 | printk(", at: "); |
534 | print_ip_sym(hlock->acquire_ip); | |
535 | } | |
536 | ||
537 | static void lockdep_print_held_locks(struct task_struct *curr) | |
538 | { | |
539 | int i, depth = curr->lockdep_depth; | |
540 | ||
541 | if (!depth) { | |
ba25f9dc | 542 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
543 | return; |
544 | } | |
545 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 546 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
547 | |
548 | for (i = 0; i < depth; i++) { | |
549 | printk(" #%d: ", i); | |
550 | print_lock(curr->held_locks + i); | |
551 | } | |
552 | } | |
fbb9ce95 IM |
553 | |
554 | static void print_lock_class_header(struct lock_class *class, int depth) | |
555 | { | |
556 | int bit; | |
557 | ||
f9829cce | 558 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
559 | print_lock_name(class); |
560 | printk(" ops: %lu", class->ops); | |
561 | printk(" {\n"); | |
562 | ||
563 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
564 | if (class->usage_mask & (1 << bit)) { | |
565 | int len = depth; | |
566 | ||
f9829cce | 567 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
568 | len += printk(" at:\n"); |
569 | print_stack_trace(class->usage_traces + bit, len); | |
570 | } | |
571 | } | |
f9829cce | 572 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 573 | |
f9829cce | 574 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
575 | print_ip_sym((unsigned long)class->key); |
576 | } | |
577 | ||
24208ca7 ML |
578 | /* |
579 | * printk the shortest lock dependencies from @start to @end in reverse order: | |
580 | */ | |
581 | static void __used | |
582 | print_shortest_lock_dependencies(struct lock_list *leaf, | |
583 | struct lock_list *root) | |
584 | { | |
585 | struct lock_list *entry = leaf; | |
586 | int depth; | |
587 | ||
588 | /*compute depth from generated tree by BFS*/ | |
589 | depth = get_lock_depth(leaf); | |
590 | ||
591 | do { | |
592 | print_lock_class_header(entry->class, depth); | |
593 | printk("%*s ... acquired at:\n", depth, ""); | |
594 | print_stack_trace(&entry->trace, 2); | |
595 | printk("\n"); | |
596 | ||
597 | if (depth == 0 && (entry != root)) { | |
598 | printk("lockdep:%s bad BFS generated tree\n", __func__); | |
599 | break; | |
600 | } | |
601 | ||
602 | entry = get_lock_parent(entry); | |
603 | depth--; | |
604 | } while (entry && (depth >= 0)); | |
605 | ||
606 | return; | |
607 | } | |
fbb9ce95 IM |
608 | /* |
609 | * printk all lock dependencies starting at <entry>: | |
610 | */ | |
7807fafa IM |
611 | static void __used |
612 | print_lock_dependencies(struct lock_class *class, int depth) | |
fbb9ce95 IM |
613 | { |
614 | struct lock_list *entry; | |
615 | ||
419ca3f1 DM |
616 | if (lockdep_dependency_visit(class, depth)) |
617 | return; | |
618 | ||
fbb9ce95 IM |
619 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) |
620 | return; | |
621 | ||
622 | print_lock_class_header(class, depth); | |
623 | ||
624 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
625 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
626 | return; | |
627 | ||
fbb9ce95 IM |
628 | print_lock_dependencies(entry->class, depth + 1); |
629 | ||
f9829cce | 630 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
631 | print_stack_trace(&entry->trace, 2); |
632 | printk("\n"); | |
633 | } | |
634 | } | |
635 | ||
8e18257d PZ |
636 | static void print_kernel_version(void) |
637 | { | |
638 | printk("%s %.*s\n", init_utsname()->release, | |
639 | (int)strcspn(init_utsname()->version, " "), | |
640 | init_utsname()->version); | |
641 | } | |
642 | ||
643 | static int very_verbose(struct lock_class *class) | |
644 | { | |
645 | #if VERY_VERBOSE | |
646 | return class_filter(class); | |
647 | #endif | |
648 | return 0; | |
649 | } | |
650 | ||
fbb9ce95 | 651 | /* |
8e18257d | 652 | * Is this the address of a static object: |
fbb9ce95 | 653 | */ |
8e18257d | 654 | static int static_obj(void *obj) |
fbb9ce95 | 655 | { |
8e18257d PZ |
656 | unsigned long start = (unsigned long) &_stext, |
657 | end = (unsigned long) &_end, | |
658 | addr = (unsigned long) obj; | |
659 | #ifdef CONFIG_SMP | |
660 | int i; | |
661 | #endif | |
662 | ||
fbb9ce95 | 663 | /* |
8e18257d | 664 | * static variable? |
fbb9ce95 | 665 | */ |
8e18257d PZ |
666 | if ((addr >= start) && (addr < end)) |
667 | return 1; | |
fbb9ce95 | 668 | |
8e18257d | 669 | #ifdef CONFIG_SMP |
fbb9ce95 | 670 | /* |
8e18257d | 671 | * percpu var? |
fbb9ce95 | 672 | */ |
8e18257d PZ |
673 | for_each_possible_cpu(i) { |
674 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
675 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
676 | + per_cpu_offset(i); | |
fbb9ce95 | 677 | |
8e18257d PZ |
678 | if ((addr >= start) && (addr < end)) |
679 | return 1; | |
680 | } | |
ca58abcb | 681 | #endif |
fbb9ce95 | 682 | |
8e18257d PZ |
683 | /* |
684 | * module var? | |
685 | */ | |
686 | return is_module_address(addr); | |
99de055a DJ |
687 | } |
688 | ||
fbb9ce95 | 689 | /* |
8e18257d PZ |
690 | * To make lock name printouts unique, we calculate a unique |
691 | * class->name_version generation counter: | |
fbb9ce95 | 692 | */ |
8e18257d | 693 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 694 | { |
8e18257d PZ |
695 | struct lock_class *class; |
696 | int count = 0; | |
fbb9ce95 | 697 | |
8e18257d | 698 | if (!new_class->name) |
fbb9ce95 IM |
699 | return 0; |
700 | ||
8e18257d PZ |
701 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
702 | if (new_class->key - new_class->subclass == class->key) | |
703 | return class->name_version; | |
704 | if (class->name && !strcmp(class->name, new_class->name)) | |
705 | count = max(count, class->name_version); | |
706 | } | |
fbb9ce95 | 707 | |
8e18257d | 708 | return count + 1; |
fbb9ce95 IM |
709 | } |
710 | ||
8e18257d PZ |
711 | /* |
712 | * Register a lock's class in the hash-table, if the class is not present | |
713 | * yet. Otherwise we look it up. We cache the result in the lock object | |
714 | * itself, so actual lookup of the hash should be once per lock object. | |
715 | */ | |
716 | static inline struct lock_class * | |
717 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 718 | { |
8e18257d PZ |
719 | struct lockdep_subclass_key *key; |
720 | struct list_head *hash_head; | |
721 | struct lock_class *class; | |
fbb9ce95 | 722 | |
8e18257d PZ |
723 | #ifdef CONFIG_DEBUG_LOCKDEP |
724 | /* | |
725 | * If the architecture calls into lockdep before initializing | |
726 | * the hashes then we'll warn about it later. (we cannot printk | |
727 | * right now) | |
728 | */ | |
729 | if (unlikely(!lockdep_initialized)) { | |
730 | lockdep_init(); | |
731 | lockdep_init_error = 1; | |
c71063c9 | 732 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
733 | } |
734 | #endif | |
fbb9ce95 | 735 | |
8e18257d PZ |
736 | /* |
737 | * Static locks do not have their class-keys yet - for them the key | |
738 | * is the lock object itself: | |
739 | */ | |
740 | if (unlikely(!lock->key)) | |
741 | lock->key = (void *)lock; | |
fbb9ce95 | 742 | |
8e18257d PZ |
743 | /* |
744 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
745 | * lock_class_key variable is passed in through the mutex_init() | |
746 | * (or spin_lock_init()) call - which acts as the key. For static | |
747 | * locks we use the lock object itself as the key. | |
748 | */ | |
4b32d0a4 PZ |
749 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
750 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 751 | |
8e18257d | 752 | key = lock->key->subkeys + subclass; |
ca268c69 | 753 | |
8e18257d | 754 | hash_head = classhashentry(key); |
74c383f1 | 755 | |
8e18257d PZ |
756 | /* |
757 | * We can walk the hash lockfree, because the hash only | |
758 | * grows, and we are careful when adding entries to the end: | |
759 | */ | |
4b32d0a4 PZ |
760 | list_for_each_entry(class, hash_head, hash_entry) { |
761 | if (class->key == key) { | |
762 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 763 | return class; |
4b32d0a4 PZ |
764 | } |
765 | } | |
fbb9ce95 | 766 | |
8e18257d | 767 | return NULL; |
fbb9ce95 IM |
768 | } |
769 | ||
770 | /* | |
8e18257d PZ |
771 | * Register a lock's class in the hash-table, if the class is not present |
772 | * yet. Otherwise we look it up. We cache the result in the lock object | |
773 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 774 | */ |
8e18257d PZ |
775 | static inline struct lock_class * |
776 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 777 | { |
8e18257d PZ |
778 | struct lockdep_subclass_key *key; |
779 | struct list_head *hash_head; | |
780 | struct lock_class *class; | |
781 | unsigned long flags; | |
782 | ||
783 | class = look_up_lock_class(lock, subclass); | |
784 | if (likely(class)) | |
785 | return class; | |
786 | ||
787 | /* | |
788 | * Debug-check: all keys must be persistent! | |
789 | */ | |
790 | if (!static_obj(lock->key)) { | |
791 | debug_locks_off(); | |
792 | printk("INFO: trying to register non-static key.\n"); | |
793 | printk("the code is fine but needs lockdep annotation.\n"); | |
794 | printk("turning off the locking correctness validator.\n"); | |
795 | dump_stack(); | |
796 | ||
797 | return NULL; | |
798 | } | |
799 | ||
800 | key = lock->key->subkeys + subclass; | |
801 | hash_head = classhashentry(key); | |
802 | ||
803 | raw_local_irq_save(flags); | |
804 | if (!graph_lock()) { | |
805 | raw_local_irq_restore(flags); | |
806 | return NULL; | |
807 | } | |
808 | /* | |
809 | * We have to do the hash-walk again, to avoid races | |
810 | * with another CPU: | |
811 | */ | |
812 | list_for_each_entry(class, hash_head, hash_entry) | |
813 | if (class->key == key) | |
814 | goto out_unlock_set; | |
815 | /* | |
816 | * Allocate a new key from the static array, and add it to | |
817 | * the hash: | |
818 | */ | |
819 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
820 | if (!debug_locks_off_graph_unlock()) { | |
821 | raw_local_irq_restore(flags); | |
822 | return NULL; | |
823 | } | |
824 | raw_local_irq_restore(flags); | |
825 | ||
826 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
827 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 828 | dump_stack(); |
8e18257d PZ |
829 | return NULL; |
830 | } | |
831 | class = lock_classes + nr_lock_classes++; | |
832 | debug_atomic_inc(&nr_unused_locks); | |
833 | class->key = key; | |
834 | class->name = lock->name; | |
835 | class->subclass = subclass; | |
836 | INIT_LIST_HEAD(&class->lock_entry); | |
837 | INIT_LIST_HEAD(&class->locks_before); | |
838 | INIT_LIST_HEAD(&class->locks_after); | |
839 | class->name_version = count_matching_names(class); | |
840 | /* | |
841 | * We use RCU's safe list-add method to make | |
842 | * parallel walking of the hash-list safe: | |
843 | */ | |
844 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
845 | /* |
846 | * Add it to the global list of classes: | |
847 | */ | |
848 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
849 | |
850 | if (verbose(class)) { | |
851 | graph_unlock(); | |
852 | raw_local_irq_restore(flags); | |
853 | ||
854 | printk("\nnew class %p: %s", class->key, class->name); | |
855 | if (class->name_version > 1) | |
856 | printk("#%d", class->name_version); | |
857 | printk("\n"); | |
858 | dump_stack(); | |
859 | ||
860 | raw_local_irq_save(flags); | |
861 | if (!graph_lock()) { | |
862 | raw_local_irq_restore(flags); | |
863 | return NULL; | |
864 | } | |
865 | } | |
866 | out_unlock_set: | |
867 | graph_unlock(); | |
868 | raw_local_irq_restore(flags); | |
869 | ||
870 | if (!subclass || force) | |
871 | lock->class_cache = class; | |
872 | ||
873 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
874 | return NULL; | |
875 | ||
876 | return class; | |
877 | } | |
878 | ||
879 | #ifdef CONFIG_PROVE_LOCKING | |
880 | /* | |
881 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
882 | * with NULL on failure) | |
883 | */ | |
884 | static struct lock_list *alloc_list_entry(void) | |
885 | { | |
886 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
887 | if (!debug_locks_off_graph_unlock()) | |
888 | return NULL; | |
889 | ||
890 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
891 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 892 | dump_stack(); |
8e18257d PZ |
893 | return NULL; |
894 | } | |
895 | return list_entries + nr_list_entries++; | |
896 | } | |
897 | ||
898 | /* | |
899 | * Add a new dependency to the head of the list: | |
900 | */ | |
901 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
902 | struct list_head *head, unsigned long ip, int distance) | |
903 | { | |
904 | struct lock_list *entry; | |
905 | /* | |
906 | * Lock not present yet - get a new dependency struct and | |
907 | * add it to the list: | |
908 | */ | |
909 | entry = alloc_list_entry(); | |
910 | if (!entry) | |
911 | return 0; | |
912 | ||
8e18257d PZ |
913 | if (!save_trace(&entry->trace)) |
914 | return 0; | |
915 | ||
74870172 ZY |
916 | entry->class = this; |
917 | entry->distance = distance; | |
8e18257d PZ |
918 | /* |
919 | * Since we never remove from the dependency list, the list can | |
920 | * be walked lockless by other CPUs, it's only allocation | |
921 | * that must be protected by the spinlock. But this also means | |
922 | * we must make new entries visible only once writes to the | |
923 | * entry become visible - hence the RCU op: | |
924 | */ | |
925 | list_add_tail_rcu(&entry->entry, head); | |
926 | ||
927 | return 1; | |
928 | } | |
929 | ||
d588e461 | 930 | unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)]; |
c94aa5ca | 931 | static struct circular_queue lock_cq; |
d588e461 | 932 | |
9e2d551e ML |
933 | static int __bfs(struct lock_list *source_entry, |
934 | void *data, | |
935 | int (*match)(struct lock_list *entry, void *data), | |
936 | struct lock_list **target_entry, | |
937 | int forward) | |
c94aa5ca ML |
938 | { |
939 | struct lock_list *entry; | |
d588e461 | 940 | struct list_head *head; |
c94aa5ca ML |
941 | struct circular_queue *cq = &lock_cq; |
942 | int ret = 1; | |
943 | ||
9e2d551e | 944 | if (match(source_entry, data)) { |
c94aa5ca ML |
945 | *target_entry = source_entry; |
946 | ret = 0; | |
947 | goto exit; | |
948 | } | |
949 | ||
d588e461 ML |
950 | if (forward) |
951 | head = &source_entry->class->locks_after; | |
952 | else | |
953 | head = &source_entry->class->locks_before; | |
954 | ||
955 | if (list_empty(head)) | |
956 | goto exit; | |
957 | ||
958 | __cq_init(cq); | |
c94aa5ca ML |
959 | __cq_enqueue(cq, (unsigned long)source_entry); |
960 | ||
961 | while (!__cq_empty(cq)) { | |
962 | struct lock_list *lock; | |
c94aa5ca ML |
963 | |
964 | __cq_dequeue(cq, (unsigned long *)&lock); | |
965 | ||
966 | if (!lock->class) { | |
967 | ret = -2; | |
968 | goto exit; | |
969 | } | |
970 | ||
971 | if (forward) | |
972 | head = &lock->class->locks_after; | |
973 | else | |
974 | head = &lock->class->locks_before; | |
975 | ||
976 | list_for_each_entry(entry, head, entry) { | |
977 | if (!lock_accessed(entry)) { | |
978 | mark_lock_accessed(entry, lock); | |
9e2d551e | 979 | if (match(entry, data)) { |
c94aa5ca ML |
980 | *target_entry = entry; |
981 | ret = 0; | |
982 | goto exit; | |
983 | } | |
984 | ||
985 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
986 | ret = -1; | |
987 | goto exit; | |
988 | } | |
989 | } | |
990 | } | |
991 | } | |
992 | exit: | |
993 | return ret; | |
994 | } | |
995 | ||
d7aaba14 | 996 | static inline int __bfs_forwards(struct lock_list *src_entry, |
9e2d551e ML |
997 | void *data, |
998 | int (*match)(struct lock_list *entry, void *data), | |
999 | struct lock_list **target_entry) | |
c94aa5ca | 1000 | { |
9e2d551e | 1001 | return __bfs(src_entry, data, match, target_entry, 1); |
c94aa5ca ML |
1002 | |
1003 | } | |
1004 | ||
d7aaba14 | 1005 | static inline int __bfs_backwards(struct lock_list *src_entry, |
9e2d551e ML |
1006 | void *data, |
1007 | int (*match)(struct lock_list *entry, void *data), | |
1008 | struct lock_list **target_entry) | |
c94aa5ca | 1009 | { |
9e2d551e | 1010 | return __bfs(src_entry, data, match, target_entry, 0); |
c94aa5ca ML |
1011 | |
1012 | } | |
1013 | ||
8e18257d PZ |
1014 | /* |
1015 | * Recursive, forwards-direction lock-dependency checking, used for | |
1016 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
1017 | * checking. | |
8e18257d | 1018 | */ |
8e18257d PZ |
1019 | |
1020 | /* | |
1021 | * Print a dependency chain entry (this is only done when a deadlock | |
1022 | * has been detected): | |
1023 | */ | |
1024 | static noinline int | |
24208ca7 | 1025 | print_circular_bug_entry(struct lock_list *target, int depth) |
8e18257d PZ |
1026 | { |
1027 | if (debug_locks_silent) | |
1028 | return 0; | |
1029 | printk("\n-> #%u", depth); | |
1030 | print_lock_name(target->class); | |
1031 | printk(":\n"); | |
1032 | print_stack_trace(&target->trace, 6); | |
1033 | ||
1034 | return 0; | |
1035 | } | |
1036 | ||
1037 | /* | |
1038 | * When a circular dependency is detected, print the | |
1039 | * header first: | |
1040 | */ | |
1041 | static noinline int | |
db0002a3 ML |
1042 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
1043 | struct held_lock *check_src, | |
1044 | struct held_lock *check_tgt) | |
8e18257d PZ |
1045 | { |
1046 | struct task_struct *curr = current; | |
1047 | ||
c94aa5ca | 1048 | if (debug_locks_silent) |
8e18257d PZ |
1049 | return 0; |
1050 | ||
1051 | printk("\n=======================================================\n"); | |
1052 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1053 | print_kernel_version(); | |
1054 | printk( "-------------------------------------------------------\n"); | |
1055 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1056 | curr->comm, task_pid_nr(curr)); |
db0002a3 | 1057 | print_lock(check_src); |
8e18257d | 1058 | printk("\nbut task is already holding lock:\n"); |
db0002a3 | 1059 | print_lock(check_tgt); |
8e18257d PZ |
1060 | printk("\nwhich lock already depends on the new lock.\n\n"); |
1061 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1062 | ||
1063 | print_circular_bug_entry(entry, depth); | |
1064 | ||
1065 | return 0; | |
1066 | } | |
1067 | ||
9e2d551e ML |
1068 | static inline int class_equal(struct lock_list *entry, void *data) |
1069 | { | |
1070 | return entry->class == data; | |
1071 | } | |
1072 | ||
db0002a3 ML |
1073 | static noinline int print_circular_bug(struct lock_list *this, |
1074 | struct lock_list *target, | |
1075 | struct held_lock *check_src, | |
1076 | struct held_lock *check_tgt) | |
8e18257d PZ |
1077 | { |
1078 | struct task_struct *curr = current; | |
c94aa5ca | 1079 | struct lock_list *parent; |
24208ca7 | 1080 | int depth; |
8e18257d | 1081 | |
c94aa5ca | 1082 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1083 | return 0; |
1084 | ||
db0002a3 | 1085 | if (!save_trace(&this->trace)) |
8e18257d PZ |
1086 | return 0; |
1087 | ||
c94aa5ca ML |
1088 | depth = get_lock_depth(target); |
1089 | ||
db0002a3 | 1090 | print_circular_bug_header(target, depth, check_src, check_tgt); |
c94aa5ca ML |
1091 | |
1092 | parent = get_lock_parent(target); | |
1093 | ||
1094 | while (parent) { | |
1095 | print_circular_bug_entry(parent, --depth); | |
1096 | parent = get_lock_parent(parent); | |
1097 | } | |
8e18257d PZ |
1098 | |
1099 | printk("\nother info that might help us debug this:\n\n"); | |
1100 | lockdep_print_held_locks(curr); | |
1101 | ||
1102 | printk("\nstack backtrace:\n"); | |
1103 | dump_stack(); | |
1104 | ||
1105 | return 0; | |
1106 | } | |
1107 | ||
db0002a3 ML |
1108 | static noinline int print_bfs_bug(int ret) |
1109 | { | |
1110 | if (!debug_locks_off_graph_unlock()) | |
1111 | return 0; | |
1112 | ||
1113 | WARN(1, "lockdep bfs error:%d\n", ret); | |
1114 | ||
1115 | return 0; | |
1116 | } | |
1117 | ||
419ca3f1 DM |
1118 | unsigned long __lockdep_count_forward_deps(struct lock_class *class, |
1119 | unsigned int depth) | |
1120 | { | |
1121 | struct lock_list *entry; | |
1122 | unsigned long ret = 1; | |
1123 | ||
1124 | if (lockdep_dependency_visit(class, depth)) | |
1125 | return 0; | |
1126 | ||
1127 | /* | |
1128 | * Recurse this class's dependency list: | |
1129 | */ | |
1130 | list_for_each_entry(entry, &class->locks_after, entry) | |
1131 | ret += __lockdep_count_forward_deps(entry->class, depth + 1); | |
1132 | ||
1133 | return ret; | |
1134 | } | |
1135 | ||
1136 | unsigned long lockdep_count_forward_deps(struct lock_class *class) | |
1137 | { | |
1138 | unsigned long ret, flags; | |
1139 | ||
1140 | local_irq_save(flags); | |
1141 | __raw_spin_lock(&lockdep_lock); | |
1142 | ret = __lockdep_count_forward_deps(class, 0); | |
1143 | __raw_spin_unlock(&lockdep_lock); | |
1144 | local_irq_restore(flags); | |
1145 | ||
1146 | return ret; | |
1147 | } | |
1148 | ||
1149 | unsigned long __lockdep_count_backward_deps(struct lock_class *class, | |
1150 | unsigned int depth) | |
1151 | { | |
1152 | struct lock_list *entry; | |
1153 | unsigned long ret = 1; | |
1154 | ||
1155 | if (lockdep_dependency_visit(class, depth)) | |
1156 | return 0; | |
1157 | /* | |
1158 | * Recurse this class's dependency list: | |
1159 | */ | |
1160 | list_for_each_entry(entry, &class->locks_before, entry) | |
1161 | ret += __lockdep_count_backward_deps(entry->class, depth + 1); | |
1162 | ||
1163 | return ret; | |
1164 | } | |
1165 | ||
1166 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1167 | { | |
1168 | unsigned long ret, flags; | |
1169 | ||
1170 | local_irq_save(flags); | |
1171 | __raw_spin_lock(&lockdep_lock); | |
1172 | ret = __lockdep_count_backward_deps(class, 0); | |
1173 | __raw_spin_unlock(&lockdep_lock); | |
1174 | local_irq_restore(flags); | |
1175 | ||
1176 | return ret; | |
1177 | } | |
1178 | ||
8e18257d PZ |
1179 | /* |
1180 | * Prove that the dependency graph starting at <entry> can not | |
1181 | * lead to <target>. Print an error and return 0 if it does. | |
1182 | */ | |
1183 | static noinline int | |
db0002a3 ML |
1184 | check_noncircular(struct lock_list *root, struct lock_class *target, |
1185 | struct lock_list **target_entry) | |
8e18257d | 1186 | { |
db0002a3 | 1187 | int result; |
8e18257d | 1188 | |
db0002a3 | 1189 | debug_atomic_inc(&nr_cyclic_checks); |
419ca3f1 | 1190 | |
d7aaba14 | 1191 | result = __bfs_forwards(root, target, class_equal, target_entry); |
fbb9ce95 | 1192 | |
db0002a3 ML |
1193 | return result; |
1194 | } | |
c94aa5ca | 1195 | |
81d68a96 | 1196 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1197 | /* |
1198 | * Forwards and backwards subgraph searching, for the purposes of | |
1199 | * proving that two subgraphs can be connected by a new dependency | |
1200 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1201 | */ | |
fbb9ce95 | 1202 | |
d7aaba14 ML |
1203 | |
1204 | #define BFS_PROCESS_RET(ret) do { \ | |
1205 | if (ret < 0) \ | |
1206 | return print_bfs_bug(ret); \ | |
1207 | if (ret == 1) \ | |
1208 | return 1; \ | |
1209 | } while (0) | |
1210 | ||
1211 | static inline int usage_match(struct lock_list *entry, void *bit) | |
1212 | { | |
1213 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); | |
1214 | } | |
1215 | ||
1216 | ||
1217 | ||
fbb9ce95 IM |
1218 | /* |
1219 | * Find a node in the forwards-direction dependency sub-graph starting | |
d7aaba14 | 1220 | * at @root->class that matches @bit. |
fbb9ce95 | 1221 | * |
d7aaba14 ML |
1222 | * Return 0 if such a node exists in the subgraph, and put that node |
1223 | * into *@target_entry. | |
fbb9ce95 | 1224 | * |
d7aaba14 ML |
1225 | * Return 1 otherwise and keep *@target_entry unchanged. |
1226 | * Return <0 on error. | |
fbb9ce95 | 1227 | */ |
d7aaba14 ML |
1228 | static int |
1229 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, | |
1230 | struct lock_list **target_entry) | |
fbb9ce95 | 1231 | { |
d7aaba14 | 1232 | int result; |
fbb9ce95 IM |
1233 | |
1234 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
fbb9ce95 | 1235 | |
d7aaba14 ML |
1236 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
1237 | ||
1238 | return result; | |
fbb9ce95 IM |
1239 | } |
1240 | ||
1241 | /* | |
1242 | * Find a node in the backwards-direction dependency sub-graph starting | |
d7aaba14 | 1243 | * at @root->class that matches @bit. |
fbb9ce95 | 1244 | * |
d7aaba14 ML |
1245 | * Return 0 if such a node exists in the subgraph, and put that node |
1246 | * into *@target_entry. | |
fbb9ce95 | 1247 | * |
d7aaba14 ML |
1248 | * Return 1 otherwise and keep *@target_entry unchanged. |
1249 | * Return <0 on error. | |
fbb9ce95 | 1250 | */ |
d7aaba14 ML |
1251 | static int |
1252 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, | |
1253 | struct lock_list **target_entry) | |
fbb9ce95 | 1254 | { |
d7aaba14 | 1255 | int result; |
fbb9ce95 IM |
1256 | |
1257 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
fbb9ce95 | 1258 | |
d7aaba14 | 1259 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
f82b217e | 1260 | |
d7aaba14 | 1261 | return result; |
fbb9ce95 IM |
1262 | } |
1263 | ||
d7aaba14 | 1264 | |
fbb9ce95 IM |
1265 | static int |
1266 | print_bad_irq_dependency(struct task_struct *curr, | |
24208ca7 ML |
1267 | struct lock_list *prev_root, |
1268 | struct lock_list *next_root, | |
1269 | struct lock_list *backwards_entry, | |
1270 | struct lock_list *forwards_entry, | |
fbb9ce95 IM |
1271 | struct held_lock *prev, |
1272 | struct held_lock *next, | |
1273 | enum lock_usage_bit bit1, | |
1274 | enum lock_usage_bit bit2, | |
1275 | const char *irqclass) | |
1276 | { | |
74c383f1 | 1277 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1278 | return 0; |
1279 | ||
1280 | printk("\n======================================================\n"); | |
1281 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1282 | irqclass, irqclass); | |
99de055a | 1283 | print_kernel_version(); |
fbb9ce95 IM |
1284 | printk( "------------------------------------------------------\n"); |
1285 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1286 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1287 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1288 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1289 | curr->hardirqs_enabled, | |
1290 | curr->softirqs_enabled); | |
1291 | print_lock(next); | |
1292 | ||
1293 | printk("\nand this task is already holding:\n"); | |
1294 | print_lock(prev); | |
1295 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1296 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1297 | printk(" ->"); |
f82b217e | 1298 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1299 | printk("\n"); |
1300 | ||
1301 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1302 | irqclass); | |
24208ca7 | 1303 | print_lock_name(backwards_entry->class); |
fbb9ce95 IM |
1304 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
1305 | ||
24208ca7 | 1306 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
fbb9ce95 IM |
1307 | |
1308 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
24208ca7 | 1309 | print_lock_name(forwards_entry->class); |
fbb9ce95 IM |
1310 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
1311 | printk("..."); | |
1312 | ||
24208ca7 | 1313 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
fbb9ce95 IM |
1314 | |
1315 | printk("\nother info that might help us debug this:\n\n"); | |
1316 | lockdep_print_held_locks(curr); | |
1317 | ||
24208ca7 ML |
1318 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
1319 | printk(" and the holding lock:\n"); | |
1320 | if (!save_trace(&prev_root->trace)) | |
1321 | return 0; | |
1322 | print_shortest_lock_dependencies(backwards_entry, prev_root); | |
fbb9ce95 | 1323 | |
24208ca7 ML |
1324 | printk("\nthe dependencies between the lock to be acquired"); |
1325 | printk(" and %s-irq-unsafe lock:\n", irqclass); | |
1326 | if (!save_trace(&next_root->trace)) | |
1327 | return 0; | |
1328 | print_shortest_lock_dependencies(forwards_entry, next_root); | |
fbb9ce95 IM |
1329 | |
1330 | printk("\nstack backtrace:\n"); | |
1331 | dump_stack(); | |
1332 | ||
1333 | return 0; | |
1334 | } | |
1335 | ||
1336 | static int | |
1337 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1338 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1339 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1340 | { | |
1341 | int ret; | |
24208ca7 | 1342 | struct lock_list this, that; |
d7aaba14 | 1343 | struct lock_list *uninitialized_var(target_entry); |
24208ca7 | 1344 | struct lock_list *uninitialized_var(target_entry1); |
d7aaba14 ML |
1345 | |
1346 | this.parent = NULL; | |
1347 | ||
1348 | this.class = hlock_class(prev); | |
1349 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); | |
1350 | BFS_PROCESS_RET(ret); | |
d7aaba14 | 1351 | |
24208ca7 ML |
1352 | that.parent = NULL; |
1353 | that.class = hlock_class(next); | |
1354 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); | |
d7aaba14 | 1355 | BFS_PROCESS_RET(ret); |
fbb9ce95 | 1356 | |
24208ca7 ML |
1357 | return print_bad_irq_dependency(curr, &this, &that, |
1358 | target_entry, target_entry1, | |
1359 | prev, next, | |
fbb9ce95 IM |
1360 | bit_backwards, bit_forwards, irqclass); |
1361 | } | |
1362 | ||
4f367d8a PZ |
1363 | static const char *state_names[] = { |
1364 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1365 | __stringify(__STATE), |
4f367d8a PZ |
1366 | #include "lockdep_states.h" |
1367 | #undef LOCKDEP_STATE | |
1368 | }; | |
1369 | ||
1370 | static const char *state_rnames[] = { | |
1371 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1372 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1373 | #include "lockdep_states.h" |
1374 | #undef LOCKDEP_STATE | |
1375 | }; | |
1376 | ||
1377 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1378 | { |
4f367d8a PZ |
1379 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1380 | } | |
8e18257d | 1381 | |
4f367d8a PZ |
1382 | static int exclusive_bit(int new_bit) |
1383 | { | |
8e18257d | 1384 | /* |
4f367d8a PZ |
1385 | * USED_IN |
1386 | * USED_IN_READ | |
1387 | * ENABLED | |
1388 | * ENABLED_READ | |
1389 | * | |
1390 | * bit 0 - write/read | |
1391 | * bit 1 - used_in/enabled | |
1392 | * bit 2+ state | |
8e18257d | 1393 | */ |
4f367d8a PZ |
1394 | |
1395 | int state = new_bit & ~3; | |
1396 | int dir = new_bit & 2; | |
8e18257d PZ |
1397 | |
1398 | /* | |
4f367d8a | 1399 | * keep state, bit flip the direction and strip read. |
8e18257d | 1400 | */ |
4f367d8a PZ |
1401 | return state | (dir ^ 2); |
1402 | } | |
1403 | ||
1404 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1405 | struct held_lock *next, enum lock_usage_bit bit) | |
1406 | { | |
8e18257d | 1407 | /* |
4f367d8a PZ |
1408 | * Prove that the new dependency does not connect a hardirq-safe |
1409 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1410 | * the backwards-subgraph starting at <prev>, and the |
1411 | * forwards-subgraph starting at <next>: | |
1412 | */ | |
4f367d8a PZ |
1413 | if (!check_usage(curr, prev, next, bit, |
1414 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1415 | return 0; |
1416 | ||
4f367d8a PZ |
1417 | bit++; /* _READ */ |
1418 | ||
cf40bd16 | 1419 | /* |
4f367d8a PZ |
1420 | * Prove that the new dependency does not connect a hardirq-safe-read |
1421 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1422 | * the backwards-subgraph starting at <prev>, and the |
1423 | * forwards-subgraph starting at <next>: | |
1424 | */ | |
4f367d8a PZ |
1425 | if (!check_usage(curr, prev, next, bit, |
1426 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1427 | return 0; |
1428 | ||
4f367d8a PZ |
1429 | return 1; |
1430 | } | |
1431 | ||
1432 | static int | |
1433 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1434 | struct held_lock *next) | |
1435 | { | |
1436 | #define LOCKDEP_STATE(__STATE) \ | |
1437 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1438 | return 0; |
4f367d8a PZ |
1439 | #include "lockdep_states.h" |
1440 | #undef LOCKDEP_STATE | |
cf40bd16 | 1441 | |
8e18257d PZ |
1442 | return 1; |
1443 | } | |
1444 | ||
1445 | static void inc_chains(void) | |
1446 | { | |
1447 | if (current->hardirq_context) | |
1448 | nr_hardirq_chains++; | |
1449 | else { | |
1450 | if (current->softirq_context) | |
1451 | nr_softirq_chains++; | |
1452 | else | |
1453 | nr_process_chains++; | |
1454 | } | |
1455 | } | |
1456 | ||
1457 | #else | |
1458 | ||
1459 | static inline int | |
1460 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1461 | struct held_lock *next) | |
1462 | { | |
1463 | return 1; | |
1464 | } | |
1465 | ||
1466 | static inline void inc_chains(void) | |
1467 | { | |
1468 | nr_process_chains++; | |
1469 | } | |
1470 | ||
fbb9ce95 IM |
1471 | #endif |
1472 | ||
1473 | static int | |
1474 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1475 | struct held_lock *next) | |
1476 | { | |
74c383f1 | 1477 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1478 | return 0; |
1479 | ||
1480 | printk("\n=============================================\n"); | |
1481 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1482 | print_kernel_version(); |
fbb9ce95 IM |
1483 | printk( "---------------------------------------------\n"); |
1484 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1485 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1486 | print_lock(next); |
1487 | printk("\nbut task is already holding lock:\n"); | |
1488 | print_lock(prev); | |
1489 | ||
1490 | printk("\nother info that might help us debug this:\n"); | |
1491 | lockdep_print_held_locks(curr); | |
1492 | ||
1493 | printk("\nstack backtrace:\n"); | |
1494 | dump_stack(); | |
1495 | ||
1496 | return 0; | |
1497 | } | |
1498 | ||
1499 | /* | |
1500 | * Check whether we are holding such a class already. | |
1501 | * | |
1502 | * (Note that this has to be done separately, because the graph cannot | |
1503 | * detect such classes of deadlocks.) | |
1504 | * | |
1505 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1506 | */ | |
1507 | static int | |
1508 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1509 | struct lockdep_map *next_instance, int read) | |
1510 | { | |
1511 | struct held_lock *prev; | |
7531e2f3 | 1512 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1513 | int i; |
1514 | ||
1515 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1516 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1517 | |
1518 | if (prev->instance == next->nest_lock) | |
1519 | nest = prev; | |
1520 | ||
f82b217e | 1521 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1522 | continue; |
7531e2f3 | 1523 | |
fbb9ce95 IM |
1524 | /* |
1525 | * Allow read-after-read recursion of the same | |
6c9076ec | 1526 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1527 | */ |
6c9076ec | 1528 | if ((read == 2) && prev->read) |
fbb9ce95 | 1529 | return 2; |
7531e2f3 PZ |
1530 | |
1531 | /* | |
1532 | * We're holding the nest_lock, which serializes this lock's | |
1533 | * nesting behaviour. | |
1534 | */ | |
1535 | if (nest) | |
1536 | return 2; | |
1537 | ||
fbb9ce95 IM |
1538 | return print_deadlock_bug(curr, prev, next); |
1539 | } | |
1540 | return 1; | |
1541 | } | |
1542 | ||
1543 | /* | |
1544 | * There was a chain-cache miss, and we are about to add a new dependency | |
1545 | * to a previous lock. We recursively validate the following rules: | |
1546 | * | |
1547 | * - would the adding of the <prev> -> <next> dependency create a | |
1548 | * circular dependency in the graph? [== circular deadlock] | |
1549 | * | |
1550 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1551 | * (in the full backwards-subgraph starting at <prev>) with any | |
1552 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1553 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1554 | * | |
1555 | * - does the new prev->next dependency connect any softirq-safe lock | |
1556 | * (in the full backwards-subgraph starting at <prev>) with any | |
1557 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1558 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1559 | * | |
1560 | * any of these scenarios could lead to a deadlock. | |
1561 | * | |
1562 | * Then if all the validations pass, we add the forwards and backwards | |
1563 | * dependency. | |
1564 | */ | |
1565 | static int | |
1566 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1567 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1568 | { |
1569 | struct lock_list *entry; | |
1570 | int ret; | |
db0002a3 ML |
1571 | struct lock_list this; |
1572 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 IM |
1573 | |
1574 | /* | |
1575 | * Prove that the new <prev> -> <next> dependency would not | |
1576 | * create a circular dependency in the graph. (We do this by | |
1577 | * forward-recursing into the graph starting at <next>, and | |
1578 | * checking whether we can reach <prev>.) | |
1579 | * | |
1580 | * We are using global variables to control the recursion, to | |
1581 | * keep the stackframe size of the recursive functions low: | |
1582 | */ | |
db0002a3 ML |
1583 | this.class = hlock_class(next); |
1584 | this.parent = NULL; | |
1585 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); | |
1586 | if (unlikely(!ret)) | |
1587 | return print_circular_bug(&this, target_entry, next, prev); | |
1588 | else if (unlikely(ret < 0)) | |
1589 | return print_bfs_bug(ret); | |
c94aa5ca | 1590 | |
8e18257d | 1591 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1592 | return 0; |
1593 | ||
fbb9ce95 IM |
1594 | /* |
1595 | * For recursive read-locks we do all the dependency checks, | |
1596 | * but we dont store read-triggered dependencies (only | |
1597 | * write-triggered dependencies). This ensures that only the | |
1598 | * write-side dependencies matter, and that if for example a | |
1599 | * write-lock never takes any other locks, then the reads are | |
1600 | * equivalent to a NOP. | |
1601 | */ | |
1602 | if (next->read == 2 || prev->read == 2) | |
1603 | return 1; | |
1604 | /* | |
1605 | * Is the <prev> -> <next> dependency already present? | |
1606 | * | |
1607 | * (this may occur even though this is a new chain: consider | |
1608 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1609 | * chains - the second one will be new, but L1 already has | |
1610 | * L2 added to its dependency list, due to the first chain.) | |
1611 | */ | |
f82b217e DJ |
1612 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1613 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1614 | if (distance == 1) |
1615 | entry->distance = 1; | |
fbb9ce95 | 1616 | return 2; |
068135e6 | 1617 | } |
fbb9ce95 IM |
1618 | } |
1619 | ||
1620 | /* | |
1621 | * Ok, all validations passed, add the new lock | |
1622 | * to the previous lock's dependency list: | |
1623 | */ | |
f82b217e DJ |
1624 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1625 | &hlock_class(prev)->locks_after, | |
1626 | next->acquire_ip, distance); | |
068135e6 | 1627 | |
fbb9ce95 IM |
1628 | if (!ret) |
1629 | return 0; | |
910b1b2e | 1630 | |
f82b217e DJ |
1631 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1632 | &hlock_class(next)->locks_before, | |
1633 | next->acquire_ip, distance); | |
910b1b2e JP |
1634 | if (!ret) |
1635 | return 0; | |
fbb9ce95 IM |
1636 | |
1637 | /* | |
8e18257d PZ |
1638 | * Debugging printouts: |
1639 | */ | |
f82b217e | 1640 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1641 | graph_unlock(); |
1642 | printk("\n new dependency: "); | |
f82b217e | 1643 | print_lock_name(hlock_class(prev)); |
8e18257d | 1644 | printk(" => "); |
f82b217e | 1645 | print_lock_name(hlock_class(next)); |
8e18257d | 1646 | printk("\n"); |
fbb9ce95 | 1647 | dump_stack(); |
8e18257d | 1648 | return graph_lock(); |
fbb9ce95 | 1649 | } |
8e18257d PZ |
1650 | return 1; |
1651 | } | |
fbb9ce95 | 1652 | |
8e18257d PZ |
1653 | /* |
1654 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1655 | * The ones that are relevant are (in increasing distance from curr): | |
1656 | * all consecutive trylock entries and the final non-trylock entry - or | |
1657 | * the end of this context's lock-chain - whichever comes first. | |
1658 | */ | |
1659 | static int | |
1660 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1661 | { | |
1662 | int depth = curr->lockdep_depth; | |
1663 | struct held_lock *hlock; | |
d6d897ce | 1664 | |
fbb9ce95 | 1665 | /* |
8e18257d PZ |
1666 | * Debugging checks. |
1667 | * | |
1668 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1669 | */ |
8e18257d PZ |
1670 | if (!depth) |
1671 | goto out_bug; | |
fbb9ce95 | 1672 | /* |
8e18257d PZ |
1673 | * At least two relevant locks must exist for this |
1674 | * to be a head: | |
fbb9ce95 | 1675 | */ |
8e18257d PZ |
1676 | if (curr->held_locks[depth].irq_context != |
1677 | curr->held_locks[depth-1].irq_context) | |
1678 | goto out_bug; | |
74c383f1 | 1679 | |
8e18257d PZ |
1680 | for (;;) { |
1681 | int distance = curr->lockdep_depth - depth + 1; | |
1682 | hlock = curr->held_locks + depth-1; | |
1683 | /* | |
1684 | * Only non-recursive-read entries get new dependencies | |
1685 | * added: | |
1686 | */ | |
1687 | if (hlock->read != 2) { | |
1688 | if (!check_prev_add(curr, hlock, next, distance)) | |
1689 | return 0; | |
1690 | /* | |
1691 | * Stop after the first non-trylock entry, | |
1692 | * as non-trylock entries have added their | |
1693 | * own direct dependencies already, so this | |
1694 | * lock is connected to them indirectly: | |
1695 | */ | |
1696 | if (!hlock->trylock) | |
1697 | break; | |
74c383f1 | 1698 | } |
8e18257d PZ |
1699 | depth--; |
1700 | /* | |
1701 | * End of lock-stack? | |
1702 | */ | |
1703 | if (!depth) | |
1704 | break; | |
1705 | /* | |
1706 | * Stop the search if we cross into another context: | |
1707 | */ | |
1708 | if (curr->held_locks[depth].irq_context != | |
1709 | curr->held_locks[depth-1].irq_context) | |
1710 | break; | |
fbb9ce95 | 1711 | } |
8e18257d PZ |
1712 | return 1; |
1713 | out_bug: | |
1714 | if (!debug_locks_off_graph_unlock()) | |
1715 | return 0; | |
fbb9ce95 | 1716 | |
8e18257d | 1717 | WARN_ON(1); |
fbb9ce95 | 1718 | |
8e18257d | 1719 | return 0; |
fbb9ce95 IM |
1720 | } |
1721 | ||
8e18257d | 1722 | unsigned long nr_lock_chains; |
443cd507 | 1723 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1724 | int nr_chain_hlocks; |
443cd507 HY |
1725 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1726 | ||
1727 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1728 | { | |
1729 | return lock_classes + chain_hlocks[chain->base + i]; | |
1730 | } | |
8e18257d | 1731 | |
fbb9ce95 IM |
1732 | /* |
1733 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1734 | * add it and return 1 - in this case the new dependency chain is |
1735 | * validated. If the key is already hashed, return 0. | |
1736 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1737 | */ |
443cd507 HY |
1738 | static inline int lookup_chain_cache(struct task_struct *curr, |
1739 | struct held_lock *hlock, | |
1740 | u64 chain_key) | |
fbb9ce95 | 1741 | { |
f82b217e | 1742 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1743 | struct list_head *hash_head = chainhashentry(chain_key); |
1744 | struct lock_chain *chain; | |
443cd507 | 1745 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1746 | int i, j, n, cn; |
fbb9ce95 | 1747 | |
381a2292 JP |
1748 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1749 | return 0; | |
fbb9ce95 IM |
1750 | /* |
1751 | * We can walk it lock-free, because entries only get added | |
1752 | * to the hash: | |
1753 | */ | |
1754 | list_for_each_entry(chain, hash_head, entry) { | |
1755 | if (chain->chain_key == chain_key) { | |
1756 | cache_hit: | |
1757 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1758 | if (very_verbose(class)) |
755cd900 AM |
1759 | printk("\nhash chain already cached, key: " |
1760 | "%016Lx tail class: [%p] %s\n", | |
1761 | (unsigned long long)chain_key, | |
1762 | class->key, class->name); | |
fbb9ce95 IM |
1763 | return 0; |
1764 | } | |
1765 | } | |
81fc685a | 1766 | if (very_verbose(class)) |
755cd900 AM |
1767 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1768 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1769 | /* |
1770 | * Allocate a new chain entry from the static array, and add | |
1771 | * it to the hash: | |
1772 | */ | |
74c383f1 IM |
1773 | if (!graph_lock()) |
1774 | return 0; | |
fbb9ce95 IM |
1775 | /* |
1776 | * We have to walk the chain again locked - to avoid duplicates: | |
1777 | */ | |
1778 | list_for_each_entry(chain, hash_head, entry) { | |
1779 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1780 | graph_unlock(); |
fbb9ce95 IM |
1781 | goto cache_hit; |
1782 | } | |
1783 | } | |
1784 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1785 | if (!debug_locks_off_graph_unlock()) |
1786 | return 0; | |
1787 | ||
fbb9ce95 IM |
1788 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1789 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 1790 | dump_stack(); |
fbb9ce95 IM |
1791 | return 0; |
1792 | } | |
1793 | chain = lock_chains + nr_lock_chains++; | |
1794 | chain->chain_key = chain_key; | |
443cd507 HY |
1795 | chain->irq_context = hlock->irq_context; |
1796 | /* Find the first held_lock of current chain */ | |
1797 | hlock_next = hlock; | |
1798 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1799 | hlock_curr = curr->held_locks + i; | |
1800 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1801 | break; | |
1802 | hlock_next = hlock; | |
1803 | } | |
1804 | i++; | |
1805 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1806 | cn = nr_chain_hlocks; |
1807 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1808 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1809 | if (n == cn) | |
1810 | break; | |
1811 | cn = n; | |
1812 | } | |
1813 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1814 | chain->base = cn; | |
443cd507 | 1815 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1816 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1817 | chain_hlocks[chain->base + j] = lock_id; |
1818 | } | |
1819 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1820 | } | |
fbb9ce95 IM |
1821 | list_add_tail_rcu(&chain->entry, hash_head); |
1822 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1823 | inc_chains(); |
1824 | ||
1825 | return 1; | |
1826 | } | |
1827 | ||
1828 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1829 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1830 | { |
1831 | /* | |
1832 | * Trylock needs to maintain the stack of held locks, but it | |
1833 | * does not add new dependencies, because trylock can be done | |
1834 | * in any order. | |
1835 | * | |
1836 | * We look up the chain_key and do the O(N^2) check and update of | |
1837 | * the dependencies only if this is a new dependency chain. | |
1838 | * (If lookup_chain_cache() returns with 1 it acquires | |
1839 | * graph_lock for us) | |
1840 | */ | |
1841 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1842 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1843 | /* |
1844 | * Check whether last held lock: | |
1845 | * | |
1846 | * - is irq-safe, if this lock is irq-unsafe | |
1847 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1848 | * | |
1849 | * And check whether the new lock's dependency graph | |
1850 | * could lead back to the previous lock. | |
1851 | * | |
1852 | * any of these scenarios could lead to a deadlock. If | |
1853 | * All validations | |
1854 | */ | |
1855 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1856 | ||
1857 | if (!ret) | |
1858 | return 0; | |
1859 | /* | |
1860 | * Mark recursive read, as we jump over it when | |
1861 | * building dependencies (just like we jump over | |
1862 | * trylock entries): | |
1863 | */ | |
1864 | if (ret == 2) | |
1865 | hlock->read = 2; | |
1866 | /* | |
1867 | * Add dependency only if this lock is not the head | |
1868 | * of the chain, and if it's not a secondary read-lock: | |
1869 | */ | |
1870 | if (!chain_head && ret != 2) | |
1871 | if (!check_prevs_add(curr, hlock)) | |
1872 | return 0; | |
1873 | graph_unlock(); | |
1874 | } else | |
1875 | /* after lookup_chain_cache(): */ | |
1876 | if (unlikely(!debug_locks)) | |
1877 | return 0; | |
fbb9ce95 IM |
1878 | |
1879 | return 1; | |
1880 | } | |
8e18257d PZ |
1881 | #else |
1882 | static inline int validate_chain(struct task_struct *curr, | |
1883 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1884 | int chain_head, u64 chain_key) |
8e18257d PZ |
1885 | { |
1886 | return 1; | |
1887 | } | |
ca58abcb | 1888 | #endif |
fbb9ce95 IM |
1889 | |
1890 | /* | |
1891 | * We are building curr_chain_key incrementally, so double-check | |
1892 | * it from scratch, to make sure that it's done correctly: | |
1893 | */ | |
1d09daa5 | 1894 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1895 | { |
1896 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1897 | struct held_lock *hlock, *prev_hlock = NULL; | |
1898 | unsigned int i, id; | |
1899 | u64 chain_key = 0; | |
1900 | ||
1901 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1902 | hlock = curr->held_locks + i; | |
1903 | if (chain_key != hlock->prev_chain_key) { | |
1904 | debug_locks_off(); | |
2df8b1d6 | 1905 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1906 | curr->lockdep_depth, i, |
1907 | (unsigned long long)chain_key, | |
1908 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1909 | return; |
1910 | } | |
f82b217e | 1911 | id = hlock->class_idx - 1; |
381a2292 JP |
1912 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1913 | return; | |
1914 | ||
fbb9ce95 IM |
1915 | if (prev_hlock && (prev_hlock->irq_context != |
1916 | hlock->irq_context)) | |
1917 | chain_key = 0; | |
1918 | chain_key = iterate_chain_key(chain_key, id); | |
1919 | prev_hlock = hlock; | |
1920 | } | |
1921 | if (chain_key != curr->curr_chain_key) { | |
1922 | debug_locks_off(); | |
2df8b1d6 | 1923 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1924 | curr->lockdep_depth, i, |
1925 | (unsigned long long)chain_key, | |
1926 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1927 | } |
1928 | #endif | |
1929 | } | |
1930 | ||
8e18257d PZ |
1931 | static int |
1932 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1933 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1934 | { | |
1935 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1936 | return 0; | |
1937 | ||
1938 | printk("\n=================================\n"); | |
1939 | printk( "[ INFO: inconsistent lock state ]\n"); | |
1940 | print_kernel_version(); | |
1941 | printk( "---------------------------------\n"); | |
1942 | ||
1943 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1944 | usage_str[prev_bit], usage_str[new_bit]); | |
1945 | ||
1946 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 1947 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
1948 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
1949 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1950 | trace_hardirqs_enabled(curr), | |
1951 | trace_softirqs_enabled(curr)); | |
1952 | print_lock(this); | |
1953 | ||
1954 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 1955 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
1956 | |
1957 | print_irqtrace_events(curr); | |
1958 | printk("\nother info that might help us debug this:\n"); | |
1959 | lockdep_print_held_locks(curr); | |
1960 | ||
1961 | printk("\nstack backtrace:\n"); | |
1962 | dump_stack(); | |
1963 | ||
1964 | return 0; | |
1965 | } | |
1966 | ||
1967 | /* | |
1968 | * Print out an error if an invalid bit is set: | |
1969 | */ | |
1970 | static inline int | |
1971 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1972 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1973 | { | |
f82b217e | 1974 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
1975 | return print_usage_bug(curr, this, bad_bit, new_bit); |
1976 | return 1; | |
1977 | } | |
1978 | ||
1979 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
1980 | enum lock_usage_bit new_bit); | |
1981 | ||
81d68a96 | 1982 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1983 | |
1984 | /* | |
1985 | * print irq inversion bug: | |
1986 | */ | |
1987 | static int | |
24208ca7 ML |
1988 | print_irq_inversion_bug(struct task_struct *curr, |
1989 | struct lock_list *root, struct lock_list *other, | |
fbb9ce95 IM |
1990 | struct held_lock *this, int forwards, |
1991 | const char *irqclass) | |
1992 | { | |
74c383f1 | 1993 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1994 | return 0; |
1995 | ||
1996 | printk("\n=========================================================\n"); | |
1997 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 1998 | print_kernel_version(); |
fbb9ce95 IM |
1999 | printk( "---------------------------------------------------------\n"); |
2000 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2001 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2002 | print_lock(this); |
2003 | if (forwards) | |
26575e28 | 2004 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2005 | else |
26575e28 | 2006 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
24208ca7 | 2007 | print_lock_name(other->class); |
fbb9ce95 IM |
2008 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
2009 | ||
2010 | printk("\nother info that might help us debug this:\n"); | |
2011 | lockdep_print_held_locks(curr); | |
2012 | ||
24208ca7 ML |
2013 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
2014 | if (!save_trace(&root->trace)) | |
2015 | return 0; | |
2016 | print_shortest_lock_dependencies(other, root); | |
fbb9ce95 IM |
2017 | |
2018 | printk("\nstack backtrace:\n"); | |
2019 | dump_stack(); | |
2020 | ||
2021 | return 0; | |
2022 | } | |
2023 | ||
2024 | /* | |
2025 | * Prove that in the forwards-direction subgraph starting at <this> | |
2026 | * there is no lock matching <mask>: | |
2027 | */ | |
2028 | static int | |
2029 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2030 | enum lock_usage_bit bit, const char *irqclass) | |
2031 | { | |
2032 | int ret; | |
d7aaba14 ML |
2033 | struct lock_list root; |
2034 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2035 | |
d7aaba14 ML |
2036 | root.parent = NULL; |
2037 | root.class = hlock_class(this); | |
2038 | ret = find_usage_forwards(&root, bit, &target_entry); | |
2039 | BFS_PROCESS_RET(ret); | |
fbb9ce95 | 2040 | |
24208ca7 | 2041 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2042 | this, 1, irqclass); |
fbb9ce95 IM |
2043 | } |
2044 | ||
2045 | /* | |
2046 | * Prove that in the backwards-direction subgraph starting at <this> | |
2047 | * there is no lock matching <mask>: | |
2048 | */ | |
2049 | static int | |
2050 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2051 | enum lock_usage_bit bit, const char *irqclass) | |
2052 | { | |
2053 | int ret; | |
d7aaba14 ML |
2054 | struct lock_list root; |
2055 | struct lock_list *uninitialized_var(target_entry); | |
fbb9ce95 | 2056 | |
d7aaba14 ML |
2057 | root.parent = NULL; |
2058 | root.class = hlock_class(this); | |
2059 | ret = find_usage_backwards(&root, bit, &target_entry); | |
2060 | BFS_PROCESS_RET(ret); | |
fbb9ce95 | 2061 | |
24208ca7 | 2062 | return print_irq_inversion_bug(curr, &root, target_entry, |
d7aaba14 | 2063 | this, 1, irqclass); |
fbb9ce95 IM |
2064 | } |
2065 | ||
3117df04 | 2066 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2067 | { |
2068 | printk("irq event stamp: %u\n", curr->irq_events); | |
2069 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2070 | print_ip_sym(curr->hardirq_enable_ip); | |
2071 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2072 | print_ip_sym(curr->hardirq_disable_ip); | |
2073 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2074 | print_ip_sym(curr->softirq_enable_ip); | |
2075 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2076 | print_ip_sym(curr->softirq_disable_ip); | |
2077 | } | |
2078 | ||
cd95302d | 2079 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2080 | { |
8e18257d PZ |
2081 | #if HARDIRQ_VERBOSE |
2082 | return class_filter(class); | |
2083 | #endif | |
fbb9ce95 IM |
2084 | return 0; |
2085 | } | |
2086 | ||
cd95302d | 2087 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2088 | { |
8e18257d PZ |
2089 | #if SOFTIRQ_VERBOSE |
2090 | return class_filter(class); | |
2091 | #endif | |
2092 | return 0; | |
fbb9ce95 IM |
2093 | } |
2094 | ||
cd95302d | 2095 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2096 | { |
2097 | #if RECLAIM_VERBOSE | |
2098 | return class_filter(class); | |
2099 | #endif | |
2100 | return 0; | |
2101 | } | |
2102 | ||
fbb9ce95 IM |
2103 | #define STRICT_READ_CHECKS 1 |
2104 | ||
cd95302d PZ |
2105 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2106 | #define LOCKDEP_STATE(__STATE) \ | |
2107 | __STATE##_verbose, | |
2108 | #include "lockdep_states.h" | |
2109 | #undef LOCKDEP_STATE | |
2110 | }; | |
2111 | ||
2112 | static inline int state_verbose(enum lock_usage_bit bit, | |
2113 | struct lock_class *class) | |
2114 | { | |
2115 | return state_verbose_f[bit >> 2](class); | |
2116 | } | |
2117 | ||
42c50d54 PZ |
2118 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2119 | enum lock_usage_bit bit, const char *name); | |
2120 | ||
6a6904d3 | 2121 | static int |
1c21f14e PZ |
2122 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2123 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2124 | { |
f989209e | 2125 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2126 | int read = new_bit & 1; |
42c50d54 PZ |
2127 | int dir = new_bit & 2; |
2128 | ||
38aa2714 PZ |
2129 | /* |
2130 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2131 | * has ENABLED state, which would allow recursion deadlocks. | |
2132 | * | |
2133 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2134 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2135 | */ | |
42c50d54 PZ |
2136 | check_usage_f usage = dir ? |
2137 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2138 | |
38aa2714 PZ |
2139 | /* |
2140 | * Validate that this particular lock does not have conflicting | |
2141 | * usage states. | |
2142 | */ | |
6a6904d3 PZ |
2143 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2144 | return 0; | |
42c50d54 | 2145 | |
38aa2714 PZ |
2146 | /* |
2147 | * Validate that the lock dependencies don't have conflicting usage | |
2148 | * states. | |
2149 | */ | |
2150 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2151 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2152 | return 0; |
780e820b | 2153 | |
38aa2714 PZ |
2154 | /* |
2155 | * Check for read in write conflicts | |
2156 | */ | |
2157 | if (!read) { | |
2158 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2159 | return 0; | |
2160 | ||
2161 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2162 | !usage(curr, this, excl_bit + 1, |
2163 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2164 | return 0; |
2165 | } | |
780e820b | 2166 | |
cd95302d | 2167 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2168 | return 2; |
2169 | ||
2170 | return 1; | |
2171 | } | |
2172 | ||
cf40bd16 | 2173 | enum mark_type { |
36bfb9bb PZ |
2174 | #define LOCKDEP_STATE(__STATE) __STATE, |
2175 | #include "lockdep_states.h" | |
2176 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2177 | }; |
2178 | ||
fbb9ce95 IM |
2179 | /* |
2180 | * Mark all held locks with a usage bit: | |
2181 | */ | |
1d09daa5 | 2182 | static int |
cf40bd16 | 2183 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2184 | { |
2185 | enum lock_usage_bit usage_bit; | |
2186 | struct held_lock *hlock; | |
2187 | int i; | |
2188 | ||
2189 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2190 | hlock = curr->held_locks + i; | |
2191 | ||
cf2ad4d1 PZ |
2192 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2193 | if (hlock->read) | |
2194 | usage_bit += 1; /* READ */ | |
2195 | ||
2196 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2197 | |
4ff773bb | 2198 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2199 | return 0; |
2200 | } | |
2201 | ||
2202 | return 1; | |
2203 | } | |
2204 | ||
2205 | /* | |
2206 | * Debugging helper: via this flag we know that we are in | |
2207 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2208 | */ | |
2209 | static int early_boot_irqs_enabled; | |
2210 | ||
2211 | void early_boot_irqs_off(void) | |
2212 | { | |
2213 | early_boot_irqs_enabled = 0; | |
2214 | } | |
2215 | ||
2216 | void early_boot_irqs_on(void) | |
2217 | { | |
2218 | early_boot_irqs_enabled = 1; | |
2219 | } | |
2220 | ||
2221 | /* | |
2222 | * Hardirqs will be enabled: | |
2223 | */ | |
6afe40b4 | 2224 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2225 | { |
2226 | struct task_struct *curr = current; | |
fbb9ce95 | 2227 | |
6afe40b4 | 2228 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2229 | |
fbb9ce95 IM |
2230 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2231 | return; | |
2232 | ||
2233 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2234 | return; | |
2235 | ||
2236 | if (unlikely(curr->hardirqs_enabled)) { | |
2237 | debug_atomic_inc(&redundant_hardirqs_on); | |
2238 | return; | |
2239 | } | |
2240 | /* we'll do an OFF -> ON transition: */ | |
2241 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2242 | |
2243 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2244 | return; | |
2245 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2246 | return; | |
2247 | /* | |
2248 | * We are going to turn hardirqs on, so set the | |
2249 | * usage bit for all held locks: | |
2250 | */ | |
cf40bd16 | 2251 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2252 | return; |
2253 | /* | |
2254 | * If we have softirqs enabled, then set the usage | |
2255 | * bit for all held locks. (disabled hardirqs prevented | |
2256 | * this bit from being set before) | |
2257 | */ | |
2258 | if (curr->softirqs_enabled) | |
cf40bd16 | 2259 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2260 | return; |
2261 | ||
8e18257d PZ |
2262 | curr->hardirq_enable_ip = ip; |
2263 | curr->hardirq_enable_event = ++curr->irq_events; | |
2264 | debug_atomic_inc(&hardirqs_on_events); | |
2265 | } | |
81d68a96 | 2266 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2267 | |
1d09daa5 | 2268 | void trace_hardirqs_on(void) |
81d68a96 SR |
2269 | { |
2270 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2271 | } | |
8e18257d PZ |
2272 | EXPORT_SYMBOL(trace_hardirqs_on); |
2273 | ||
2274 | /* | |
2275 | * Hardirqs were disabled: | |
2276 | */ | |
6afe40b4 | 2277 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2278 | { |
2279 | struct task_struct *curr = current; | |
2280 | ||
6afe40b4 | 2281 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2282 | |
8e18257d PZ |
2283 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2284 | return; | |
2285 | ||
2286 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2287 | return; | |
2288 | ||
2289 | if (curr->hardirqs_enabled) { | |
2290 | /* | |
2291 | * We have done an ON -> OFF transition: | |
2292 | */ | |
2293 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2294 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2295 | curr->hardirq_disable_event = ++curr->irq_events; |
2296 | debug_atomic_inc(&hardirqs_off_events); | |
2297 | } else | |
2298 | debug_atomic_inc(&redundant_hardirqs_off); | |
2299 | } | |
81d68a96 | 2300 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2301 | |
1d09daa5 | 2302 | void trace_hardirqs_off(void) |
81d68a96 SR |
2303 | { |
2304 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2305 | } | |
8e18257d PZ |
2306 | EXPORT_SYMBOL(trace_hardirqs_off); |
2307 | ||
2308 | /* | |
2309 | * Softirqs will be enabled: | |
2310 | */ | |
2311 | void trace_softirqs_on(unsigned long ip) | |
2312 | { | |
2313 | struct task_struct *curr = current; | |
2314 | ||
2315 | if (unlikely(!debug_locks)) | |
2316 | return; | |
2317 | ||
2318 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2319 | return; | |
2320 | ||
2321 | if (curr->softirqs_enabled) { | |
2322 | debug_atomic_inc(&redundant_softirqs_on); | |
2323 | return; | |
2324 | } | |
2325 | ||
2326 | /* | |
2327 | * We'll do an OFF -> ON transition: | |
2328 | */ | |
2329 | curr->softirqs_enabled = 1; | |
2330 | curr->softirq_enable_ip = ip; | |
2331 | curr->softirq_enable_event = ++curr->irq_events; | |
2332 | debug_atomic_inc(&softirqs_on_events); | |
2333 | /* | |
2334 | * We are going to turn softirqs on, so set the | |
2335 | * usage bit for all held locks, if hardirqs are | |
2336 | * enabled too: | |
2337 | */ | |
2338 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2339 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2340 | } |
2341 | ||
2342 | /* | |
2343 | * Softirqs were disabled: | |
2344 | */ | |
2345 | void trace_softirqs_off(unsigned long ip) | |
2346 | { | |
2347 | struct task_struct *curr = current; | |
2348 | ||
2349 | if (unlikely(!debug_locks)) | |
2350 | return; | |
2351 | ||
2352 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2353 | return; | |
2354 | ||
2355 | if (curr->softirqs_enabled) { | |
2356 | /* | |
2357 | * We have done an ON -> OFF transition: | |
2358 | */ | |
2359 | curr->softirqs_enabled = 0; | |
2360 | curr->softirq_disable_ip = ip; | |
2361 | curr->softirq_disable_event = ++curr->irq_events; | |
2362 | debug_atomic_inc(&softirqs_off_events); | |
2363 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2364 | } else | |
2365 | debug_atomic_inc(&redundant_softirqs_off); | |
2366 | } | |
2367 | ||
2f850181 | 2368 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2369 | { |
2370 | struct task_struct *curr = current; | |
2371 | ||
2372 | if (unlikely(!debug_locks)) | |
2373 | return; | |
2374 | ||
2375 | /* no reclaim without waiting on it */ | |
2376 | if (!(gfp_mask & __GFP_WAIT)) | |
2377 | return; | |
2378 | ||
2379 | /* this guy won't enter reclaim */ | |
2380 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2381 | return; | |
2382 | ||
2383 | /* We're only interested __GFP_FS allocations for now */ | |
2384 | if (!(gfp_mask & __GFP_FS)) | |
2385 | return; | |
2386 | ||
2f850181 | 2387 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2388 | return; |
2389 | ||
2390 | mark_held_locks(curr, RECLAIM_FS); | |
2391 | } | |
2392 | ||
2f850181 PZ |
2393 | static void check_flags(unsigned long flags); |
2394 | ||
2395 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2396 | { | |
2397 | unsigned long flags; | |
2398 | ||
2399 | if (unlikely(current->lockdep_recursion)) | |
2400 | return; | |
2401 | ||
2402 | raw_local_irq_save(flags); | |
2403 | check_flags(flags); | |
2404 | current->lockdep_recursion = 1; | |
2405 | __lockdep_trace_alloc(gfp_mask, flags); | |
2406 | current->lockdep_recursion = 0; | |
2407 | raw_local_irq_restore(flags); | |
2408 | } | |
2409 | ||
8e18257d PZ |
2410 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2411 | { | |
2412 | /* | |
2413 | * If non-trylock use in a hardirq or softirq context, then | |
2414 | * mark the lock as used in these contexts: | |
2415 | */ | |
2416 | if (!hlock->trylock) { | |
2417 | if (hlock->read) { | |
2418 | if (curr->hardirq_context) | |
2419 | if (!mark_lock(curr, hlock, | |
2420 | LOCK_USED_IN_HARDIRQ_READ)) | |
2421 | return 0; | |
2422 | if (curr->softirq_context) | |
2423 | if (!mark_lock(curr, hlock, | |
2424 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2425 | return 0; | |
2426 | } else { | |
2427 | if (curr->hardirq_context) | |
2428 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2429 | return 0; | |
2430 | if (curr->softirq_context) | |
2431 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2432 | return 0; | |
2433 | } | |
2434 | } | |
2435 | if (!hlock->hardirqs_off) { | |
2436 | if (hlock->read) { | |
2437 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2438 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2439 | return 0; |
2440 | if (curr->softirqs_enabled) | |
2441 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2442 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2443 | return 0; |
2444 | } else { | |
2445 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2446 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2447 | return 0; |
2448 | if (curr->softirqs_enabled) | |
2449 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2450 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2451 | return 0; |
2452 | } | |
2453 | } | |
2454 | ||
cf40bd16 NP |
2455 | /* |
2456 | * We reuse the irq context infrastructure more broadly as a general | |
2457 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2458 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2459 | * allocation). | |
2460 | */ | |
2461 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2462 | if (hlock->read) { | |
2463 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2464 | return 0; | |
2465 | } else { | |
2466 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2467 | return 0; | |
2468 | } | |
2469 | } | |
2470 | ||
8e18257d PZ |
2471 | return 1; |
2472 | } | |
2473 | ||
2474 | static int separate_irq_context(struct task_struct *curr, | |
2475 | struct held_lock *hlock) | |
2476 | { | |
2477 | unsigned int depth = curr->lockdep_depth; | |
2478 | ||
2479 | /* | |
2480 | * Keep track of points where we cross into an interrupt context: | |
2481 | */ | |
2482 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2483 | curr->softirq_context; | |
2484 | if (depth) { | |
2485 | struct held_lock *prev_hlock; | |
2486 | ||
2487 | prev_hlock = curr->held_locks + depth-1; | |
2488 | /* | |
2489 | * If we cross into another context, reset the | |
2490 | * hash key (this also prevents the checking and the | |
2491 | * adding of the dependency to 'prev'): | |
2492 | */ | |
2493 | if (prev_hlock->irq_context != hlock->irq_context) | |
2494 | return 1; | |
2495 | } | |
2496 | return 0; | |
fbb9ce95 IM |
2497 | } |
2498 | ||
8e18257d | 2499 | #else |
fbb9ce95 | 2500 | |
8e18257d PZ |
2501 | static inline |
2502 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2503 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2504 | { |
8e18257d PZ |
2505 | WARN_ON(1); |
2506 | return 1; | |
2507 | } | |
fbb9ce95 | 2508 | |
8e18257d PZ |
2509 | static inline int mark_irqflags(struct task_struct *curr, |
2510 | struct held_lock *hlock) | |
2511 | { | |
2512 | return 1; | |
2513 | } | |
fbb9ce95 | 2514 | |
8e18257d PZ |
2515 | static inline int separate_irq_context(struct task_struct *curr, |
2516 | struct held_lock *hlock) | |
2517 | { | |
2518 | return 0; | |
fbb9ce95 IM |
2519 | } |
2520 | ||
868a23a8 PZ |
2521 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2522 | { | |
2523 | } | |
2524 | ||
8e18257d | 2525 | #endif |
fbb9ce95 IM |
2526 | |
2527 | /* | |
8e18257d | 2528 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2529 | */ |
1d09daa5 | 2530 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2531 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2532 | { |
8e18257d | 2533 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2534 | |
2535 | /* | |
8e18257d PZ |
2536 | * If already set then do not dirty the cacheline, |
2537 | * nor do any checks: | |
fbb9ce95 | 2538 | */ |
f82b217e | 2539 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2540 | return 1; |
2541 | ||
2542 | if (!graph_lock()) | |
2543 | return 0; | |
fbb9ce95 | 2544 | /* |
8e18257d | 2545 | * Make sure we didnt race: |
fbb9ce95 | 2546 | */ |
f82b217e | 2547 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2548 | graph_unlock(); |
2549 | return 1; | |
2550 | } | |
fbb9ce95 | 2551 | |
f82b217e | 2552 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2553 | |
f82b217e | 2554 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2555 | return 0; |
fbb9ce95 | 2556 | |
8e18257d | 2557 | switch (new_bit) { |
5346417e PZ |
2558 | #define LOCKDEP_STATE(__STATE) \ |
2559 | case LOCK_USED_IN_##__STATE: \ | |
2560 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2561 | case LOCK_ENABLED_##__STATE: \ | |
2562 | case LOCK_ENABLED_##__STATE##_READ: | |
2563 | #include "lockdep_states.h" | |
2564 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2565 | ret = mark_lock_irq(curr, this, new_bit); |
2566 | if (!ret) | |
2567 | return 0; | |
2568 | break; | |
2569 | case LOCK_USED: | |
8e18257d PZ |
2570 | debug_atomic_dec(&nr_unused_locks); |
2571 | break; | |
2572 | default: | |
2573 | if (!debug_locks_off_graph_unlock()) | |
2574 | return 0; | |
2575 | WARN_ON(1); | |
2576 | return 0; | |
2577 | } | |
fbb9ce95 | 2578 | |
8e18257d PZ |
2579 | graph_unlock(); |
2580 | ||
2581 | /* | |
2582 | * We must printk outside of the graph_lock: | |
2583 | */ | |
2584 | if (ret == 2) { | |
2585 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2586 | print_lock(this); | |
2587 | print_irqtrace_events(curr); | |
2588 | dump_stack(); | |
2589 | } | |
2590 | ||
2591 | return ret; | |
2592 | } | |
fbb9ce95 IM |
2593 | |
2594 | /* | |
2595 | * Initialize a lock instance's lock-class mapping info: | |
2596 | */ | |
2597 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2598 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2599 | { |
c8a25005 PZ |
2600 | lock->class_cache = NULL; |
2601 | #ifdef CONFIG_LOCK_STAT | |
2602 | lock->cpu = raw_smp_processor_id(); | |
2603 | #endif | |
2604 | ||
2605 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2606 | lock->name = "NULL"; | |
fbb9ce95 | 2607 | return; |
c8a25005 PZ |
2608 | } |
2609 | ||
2610 | lock->name = name; | |
fbb9ce95 IM |
2611 | |
2612 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2613 | return; | |
fbb9ce95 IM |
2614 | /* |
2615 | * Sanity check, the lock-class key must be persistent: | |
2616 | */ | |
2617 | if (!static_obj(key)) { | |
2618 | printk("BUG: key %p not in .data!\n", key); | |
2619 | DEBUG_LOCKS_WARN_ON(1); | |
2620 | return; | |
2621 | } | |
fbb9ce95 | 2622 | lock->key = key; |
c8a25005 PZ |
2623 | |
2624 | if (unlikely(!debug_locks)) | |
2625 | return; | |
2626 | ||
4dfbb9d8 PZ |
2627 | if (subclass) |
2628 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2629 | } |
fbb9ce95 IM |
2630 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2631 | ||
2632 | /* | |
2633 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2634 | * We maintain the dependency maps and validate the locking attempt: | |
2635 | */ | |
2636 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2637 | int trylock, int read, int check, int hardirqs_off, | |
7531e2f3 | 2638 | struct lockdep_map *nest_lock, unsigned long ip) |
fbb9ce95 IM |
2639 | { |
2640 | struct task_struct *curr = current; | |
d6d897ce | 2641 | struct lock_class *class = NULL; |
fbb9ce95 | 2642 | struct held_lock *hlock; |
fbb9ce95 IM |
2643 | unsigned int depth, id; |
2644 | int chain_head = 0; | |
2645 | u64 chain_key; | |
2646 | ||
f20786ff PZ |
2647 | if (!prove_locking) |
2648 | check = 1; | |
2649 | ||
fbb9ce95 IM |
2650 | if (unlikely(!debug_locks)) |
2651 | return 0; | |
2652 | ||
2653 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2654 | return 0; | |
2655 | ||
2656 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2657 | debug_locks_off(); | |
2658 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2659 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2660 | dump_stack(); |
fbb9ce95 IM |
2661 | return 0; |
2662 | } | |
2663 | ||
d6d897ce IM |
2664 | if (!subclass) |
2665 | class = lock->class_cache; | |
2666 | /* | |
2667 | * Not cached yet or subclass? | |
2668 | */ | |
fbb9ce95 | 2669 | if (unlikely(!class)) { |
4dfbb9d8 | 2670 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2671 | if (!class) |
2672 | return 0; | |
2673 | } | |
2674 | debug_atomic_inc((atomic_t *)&class->ops); | |
2675 | if (very_verbose(class)) { | |
2676 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2677 | if (class->name_version > 1) | |
2678 | printk("#%d", class->name_version); | |
2679 | printk("\n"); | |
2680 | dump_stack(); | |
2681 | } | |
2682 | ||
2683 | /* | |
2684 | * Add the lock to the list of currently held locks. | |
2685 | * (we dont increase the depth just yet, up until the | |
2686 | * dependency checks are done) | |
2687 | */ | |
2688 | depth = curr->lockdep_depth; | |
2689 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2690 | return 0; | |
2691 | ||
2692 | hlock = curr->held_locks + depth; | |
f82b217e DJ |
2693 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2694 | return 0; | |
2695 | hlock->class_idx = class - lock_classes + 1; | |
fbb9ce95 IM |
2696 | hlock->acquire_ip = ip; |
2697 | hlock->instance = lock; | |
7531e2f3 | 2698 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2699 | hlock->trylock = trylock; |
2700 | hlock->read = read; | |
2701 | hlock->check = check; | |
6951b12a | 2702 | hlock->hardirqs_off = !!hardirqs_off; |
f20786ff PZ |
2703 | #ifdef CONFIG_LOCK_STAT |
2704 | hlock->waittime_stamp = 0; | |
2705 | hlock->holdtime_stamp = sched_clock(); | |
2706 | #endif | |
fbb9ce95 | 2707 | |
8e18257d PZ |
2708 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2709 | return 0; | |
2710 | ||
fbb9ce95 | 2711 | /* mark it as used: */ |
4ff773bb | 2712 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2713 | return 0; |
8e18257d | 2714 | |
fbb9ce95 | 2715 | /* |
17aacfb9 | 2716 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2717 | * lock keys along the dependency chain. We save the hash value |
2718 | * at every step so that we can get the current hash easily | |
2719 | * after unlock. The chain hash is then used to cache dependency | |
2720 | * results. | |
2721 | * | |
2722 | * The 'key ID' is what is the most compact key value to drive | |
2723 | * the hash, not class->key. | |
2724 | */ | |
2725 | id = class - lock_classes; | |
2726 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2727 | return 0; | |
2728 | ||
2729 | chain_key = curr->curr_chain_key; | |
2730 | if (!depth) { | |
2731 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2732 | return 0; | |
2733 | chain_head = 1; | |
2734 | } | |
2735 | ||
2736 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2737 | if (separate_irq_context(curr, hlock)) { |
2738 | chain_key = 0; | |
2739 | chain_head = 1; | |
fbb9ce95 | 2740 | } |
fbb9ce95 | 2741 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2742 | |
3aa416b0 | 2743 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2744 | return 0; |
381a2292 | 2745 | |
3aa416b0 | 2746 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2747 | curr->lockdep_depth++; |
2748 | check_chain_key(curr); | |
60e114d1 JP |
2749 | #ifdef CONFIG_DEBUG_LOCKDEP |
2750 | if (unlikely(!debug_locks)) | |
2751 | return 0; | |
2752 | #endif | |
fbb9ce95 IM |
2753 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2754 | debug_locks_off(); | |
2755 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2756 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2757 | dump_stack(); |
fbb9ce95 IM |
2758 | return 0; |
2759 | } | |
381a2292 | 2760 | |
fbb9ce95 IM |
2761 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2762 | max_lockdep_depth = curr->lockdep_depth; | |
2763 | ||
2764 | return 1; | |
2765 | } | |
2766 | ||
2767 | static int | |
2768 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2769 | unsigned long ip) | |
2770 | { | |
2771 | if (!debug_locks_off()) | |
2772 | return 0; | |
2773 | if (debug_locks_silent) | |
2774 | return 0; | |
2775 | ||
2776 | printk("\n=====================================\n"); | |
2777 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2778 | printk( "-------------------------------------\n"); | |
2779 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2780 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2781 | print_lockdep_cache(lock); |
2782 | printk(") at:\n"); | |
2783 | print_ip_sym(ip); | |
2784 | printk("but there are no more locks to release!\n"); | |
2785 | printk("\nother info that might help us debug this:\n"); | |
2786 | lockdep_print_held_locks(curr); | |
2787 | ||
2788 | printk("\nstack backtrace:\n"); | |
2789 | dump_stack(); | |
2790 | ||
2791 | return 0; | |
2792 | } | |
2793 | ||
2794 | /* | |
2795 | * Common debugging checks for both nested and non-nested unlock: | |
2796 | */ | |
2797 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2798 | unsigned long ip) | |
2799 | { | |
2800 | if (unlikely(!debug_locks)) | |
2801 | return 0; | |
2802 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2803 | return 0; | |
2804 | ||
2805 | if (curr->lockdep_depth <= 0) | |
2806 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2807 | ||
2808 | return 1; | |
2809 | } | |
2810 | ||
64aa348e | 2811 | static int |
00ef9f73 PZ |
2812 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2813 | struct lock_class_key *key, unsigned int subclass, | |
2814 | unsigned long ip) | |
64aa348e PZ |
2815 | { |
2816 | struct task_struct *curr = current; | |
2817 | struct held_lock *hlock, *prev_hlock; | |
2818 | struct lock_class *class; | |
2819 | unsigned int depth; | |
2820 | int i; | |
2821 | ||
2822 | depth = curr->lockdep_depth; | |
2823 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2824 | return 0; | |
2825 | ||
2826 | prev_hlock = NULL; | |
2827 | for (i = depth-1; i >= 0; i--) { | |
2828 | hlock = curr->held_locks + i; | |
2829 | /* | |
2830 | * We must not cross into another context: | |
2831 | */ | |
2832 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2833 | break; | |
2834 | if (hlock->instance == lock) | |
2835 | goto found_it; | |
2836 | prev_hlock = hlock; | |
2837 | } | |
2838 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2839 | ||
2840 | found_it: | |
00ef9f73 | 2841 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2842 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2843 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2844 | |
2845 | curr->lockdep_depth = i; | |
2846 | curr->curr_chain_key = hlock->prev_chain_key; | |
2847 | ||
2848 | for (; i < depth; i++) { | |
2849 | hlock = curr->held_locks + i; | |
2850 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2851 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2852 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2853 | hlock->nest_lock, hlock->acquire_ip)) |
64aa348e PZ |
2854 | return 0; |
2855 | } | |
2856 | ||
2857 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2858 | return 0; | |
2859 | return 1; | |
2860 | } | |
2861 | ||
fbb9ce95 IM |
2862 | /* |
2863 | * Remove the lock to the list of currently held locks in a | |
2864 | * potentially non-nested (out of order) manner. This is a | |
2865 | * relatively rare operation, as all the unlock APIs default | |
2866 | * to nested mode (which uses lock_release()): | |
2867 | */ | |
2868 | static int | |
2869 | lock_release_non_nested(struct task_struct *curr, | |
2870 | struct lockdep_map *lock, unsigned long ip) | |
2871 | { | |
2872 | struct held_lock *hlock, *prev_hlock; | |
2873 | unsigned int depth; | |
2874 | int i; | |
2875 | ||
2876 | /* | |
2877 | * Check whether the lock exists in the current stack | |
2878 | * of held locks: | |
2879 | */ | |
2880 | depth = curr->lockdep_depth; | |
2881 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2882 | return 0; | |
2883 | ||
2884 | prev_hlock = NULL; | |
2885 | for (i = depth-1; i >= 0; i--) { | |
2886 | hlock = curr->held_locks + i; | |
2887 | /* | |
2888 | * We must not cross into another context: | |
2889 | */ | |
2890 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2891 | break; | |
2892 | if (hlock->instance == lock) | |
2893 | goto found_it; | |
2894 | prev_hlock = hlock; | |
2895 | } | |
2896 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2897 | ||
2898 | found_it: | |
f20786ff PZ |
2899 | lock_release_holdtime(hlock); |
2900 | ||
fbb9ce95 IM |
2901 | /* |
2902 | * We have the right lock to unlock, 'hlock' points to it. | |
2903 | * Now we remove it from the stack, and add back the other | |
2904 | * entries (if any), recalculating the hash along the way: | |
2905 | */ | |
2906 | curr->lockdep_depth = i; | |
2907 | curr->curr_chain_key = hlock->prev_chain_key; | |
2908 | ||
2909 | for (i++; i < depth; i++) { | |
2910 | hlock = curr->held_locks + i; | |
2911 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2912 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 2913 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2914 | hlock->nest_lock, hlock->acquire_ip)) |
fbb9ce95 IM |
2915 | return 0; |
2916 | } | |
2917 | ||
2918 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2919 | return 0; | |
2920 | return 1; | |
2921 | } | |
2922 | ||
2923 | /* | |
2924 | * Remove the lock to the list of currently held locks - this gets | |
2925 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2926 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2927 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2928 | */ | |
2929 | static int lock_release_nested(struct task_struct *curr, | |
2930 | struct lockdep_map *lock, unsigned long ip) | |
2931 | { | |
2932 | struct held_lock *hlock; | |
2933 | unsigned int depth; | |
2934 | ||
2935 | /* | |
2936 | * Pop off the top of the lock stack: | |
2937 | */ | |
2938 | depth = curr->lockdep_depth - 1; | |
2939 | hlock = curr->held_locks + depth; | |
2940 | ||
2941 | /* | |
2942 | * Is the unlock non-nested: | |
2943 | */ | |
2944 | if (hlock->instance != lock) | |
2945 | return lock_release_non_nested(curr, lock, ip); | |
2946 | curr->lockdep_depth--; | |
2947 | ||
2948 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2949 | return 0; | |
2950 | ||
2951 | curr->curr_chain_key = hlock->prev_chain_key; | |
2952 | ||
f20786ff PZ |
2953 | lock_release_holdtime(hlock); |
2954 | ||
fbb9ce95 IM |
2955 | #ifdef CONFIG_DEBUG_LOCKDEP |
2956 | hlock->prev_chain_key = 0; | |
f82b217e | 2957 | hlock->class_idx = 0; |
fbb9ce95 IM |
2958 | hlock->acquire_ip = 0; |
2959 | hlock->irq_context = 0; | |
2960 | #endif | |
2961 | return 1; | |
2962 | } | |
2963 | ||
2964 | /* | |
2965 | * Remove the lock to the list of currently held locks - this gets | |
2966 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2967 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2968 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2969 | */ | |
2970 | static void | |
2971 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2972 | { | |
2973 | struct task_struct *curr = current; | |
2974 | ||
2975 | if (!check_unlock(curr, lock, ip)) | |
2976 | return; | |
2977 | ||
2978 | if (nested) { | |
2979 | if (!lock_release_nested(curr, lock, ip)) | |
2980 | return; | |
2981 | } else { | |
2982 | if (!lock_release_non_nested(curr, lock, ip)) | |
2983 | return; | |
2984 | } | |
2985 | ||
2986 | check_chain_key(curr); | |
2987 | } | |
2988 | ||
2989 | /* | |
2990 | * Check whether we follow the irq-flags state precisely: | |
2991 | */ | |
1d09daa5 | 2992 | static void check_flags(unsigned long flags) |
fbb9ce95 | 2993 | { |
992860e9 IM |
2994 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
2995 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
2996 | if (!debug_locks) |
2997 | return; | |
2998 | ||
5f9fa8a6 IM |
2999 | if (irqs_disabled_flags(flags)) { |
3000 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3001 | printk("possible reason: unannotated irqs-off.\n"); | |
3002 | } | |
3003 | } else { | |
3004 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3005 | printk("possible reason: unannotated irqs-on.\n"); | |
3006 | } | |
3007 | } | |
fbb9ce95 IM |
3008 | |
3009 | /* | |
3010 | * We dont accurately track softirq state in e.g. | |
3011 | * hardirq contexts (such as on 4KSTACKS), so only | |
3012 | * check if not in hardirq contexts: | |
3013 | */ | |
3014 | if (!hardirq_count()) { | |
3015 | if (softirq_count()) | |
3016 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3017 | else | |
3018 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3019 | } | |
3020 | ||
3021 | if (!debug_locks) | |
3022 | print_irqtrace_events(current); | |
3023 | #endif | |
3024 | } | |
3025 | ||
00ef9f73 PZ |
3026 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3027 | struct lock_class_key *key, unsigned int subclass, | |
3028 | unsigned long ip) | |
64aa348e PZ |
3029 | { |
3030 | unsigned long flags; | |
3031 | ||
3032 | if (unlikely(current->lockdep_recursion)) | |
3033 | return; | |
3034 | ||
3035 | raw_local_irq_save(flags); | |
3036 | current->lockdep_recursion = 1; | |
3037 | check_flags(flags); | |
00ef9f73 | 3038 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3039 | check_chain_key(current); |
3040 | current->lockdep_recursion = 0; | |
3041 | raw_local_irq_restore(flags); | |
3042 | } | |
00ef9f73 | 3043 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3044 | |
fbb9ce95 IM |
3045 | /* |
3046 | * We are not always called with irqs disabled - do that here, | |
3047 | * and also avoid lockdep recursion: | |
3048 | */ | |
1d09daa5 | 3049 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3050 | int trylock, int read, int check, |
3051 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3052 | { |
3053 | unsigned long flags; | |
3054 | ||
efed792d PZ |
3055 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
3056 | ||
fbb9ce95 IM |
3057 | if (unlikely(current->lockdep_recursion)) |
3058 | return; | |
3059 | ||
3060 | raw_local_irq_save(flags); | |
3061 | check_flags(flags); | |
3062 | ||
3063 | current->lockdep_recursion = 1; | |
3064 | __lock_acquire(lock, subclass, trylock, read, check, | |
7531e2f3 | 3065 | irqs_disabled_flags(flags), nest_lock, ip); |
fbb9ce95 IM |
3066 | current->lockdep_recursion = 0; |
3067 | raw_local_irq_restore(flags); | |
3068 | } | |
fbb9ce95 IM |
3069 | EXPORT_SYMBOL_GPL(lock_acquire); |
3070 | ||
1d09daa5 | 3071 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3072 | unsigned long ip) |
fbb9ce95 IM |
3073 | { |
3074 | unsigned long flags; | |
3075 | ||
efed792d PZ |
3076 | trace_lock_release(lock, nested, ip); |
3077 | ||
fbb9ce95 IM |
3078 | if (unlikely(current->lockdep_recursion)) |
3079 | return; | |
3080 | ||
3081 | raw_local_irq_save(flags); | |
3082 | check_flags(flags); | |
3083 | current->lockdep_recursion = 1; | |
3084 | __lock_release(lock, nested, ip); | |
3085 | current->lockdep_recursion = 0; | |
3086 | raw_local_irq_restore(flags); | |
3087 | } | |
fbb9ce95 IM |
3088 | EXPORT_SYMBOL_GPL(lock_release); |
3089 | ||
cf40bd16 NP |
3090 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3091 | { | |
3092 | current->lockdep_reclaim_gfp = gfp_mask; | |
3093 | } | |
3094 | ||
3095 | void lockdep_clear_current_reclaim_state(void) | |
3096 | { | |
3097 | current->lockdep_reclaim_gfp = 0; | |
3098 | } | |
3099 | ||
f20786ff PZ |
3100 | #ifdef CONFIG_LOCK_STAT |
3101 | static int | |
3102 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3103 | unsigned long ip) | |
3104 | { | |
3105 | if (!debug_locks_off()) | |
3106 | return 0; | |
3107 | if (debug_locks_silent) | |
3108 | return 0; | |
3109 | ||
3110 | printk("\n=================================\n"); | |
3111 | printk( "[ BUG: bad contention detected! ]\n"); | |
3112 | printk( "---------------------------------\n"); | |
3113 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3114 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3115 | print_lockdep_cache(lock); |
3116 | printk(") at:\n"); | |
3117 | print_ip_sym(ip); | |
3118 | printk("but there are no locks held!\n"); | |
3119 | printk("\nother info that might help us debug this:\n"); | |
3120 | lockdep_print_held_locks(curr); | |
3121 | ||
3122 | printk("\nstack backtrace:\n"); | |
3123 | dump_stack(); | |
3124 | ||
3125 | return 0; | |
3126 | } | |
3127 | ||
3128 | static void | |
3129 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3130 | { | |
3131 | struct task_struct *curr = current; | |
3132 | struct held_lock *hlock, *prev_hlock; | |
3133 | struct lock_class_stats *stats; | |
3134 | unsigned int depth; | |
c7e78cff | 3135 | int i, contention_point, contending_point; |
f20786ff PZ |
3136 | |
3137 | depth = curr->lockdep_depth; | |
3138 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3139 | return; | |
3140 | ||
3141 | prev_hlock = NULL; | |
3142 | for (i = depth-1; i >= 0; i--) { | |
3143 | hlock = curr->held_locks + i; | |
3144 | /* | |
3145 | * We must not cross into another context: | |
3146 | */ | |
3147 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3148 | break; | |
3149 | if (hlock->instance == lock) | |
3150 | goto found_it; | |
3151 | prev_hlock = hlock; | |
3152 | } | |
3153 | print_lock_contention_bug(curr, lock, ip); | |
3154 | return; | |
3155 | ||
3156 | found_it: | |
3157 | hlock->waittime_stamp = sched_clock(); | |
3158 | ||
c7e78cff PZ |
3159 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3160 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3161 | lock->ip); | |
f20786ff | 3162 | |
f82b217e | 3163 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3164 | if (contention_point < LOCKSTAT_POINTS) |
3165 | stats->contention_point[contention_point]++; | |
3166 | if (contending_point < LOCKSTAT_POINTS) | |
3167 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3168 | if (lock->cpu != smp_processor_id()) |
3169 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3170 | put_lock_stats(stats); |
3171 | } | |
3172 | ||
3173 | static void | |
c7e78cff | 3174 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3175 | { |
3176 | struct task_struct *curr = current; | |
3177 | struct held_lock *hlock, *prev_hlock; | |
3178 | struct lock_class_stats *stats; | |
3179 | unsigned int depth; | |
3180 | u64 now; | |
96645678 PZ |
3181 | s64 waittime = 0; |
3182 | int i, cpu; | |
f20786ff PZ |
3183 | |
3184 | depth = curr->lockdep_depth; | |
3185 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3186 | return; | |
3187 | ||
3188 | prev_hlock = NULL; | |
3189 | for (i = depth-1; i >= 0; i--) { | |
3190 | hlock = curr->held_locks + i; | |
3191 | /* | |
3192 | * We must not cross into another context: | |
3193 | */ | |
3194 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3195 | break; | |
3196 | if (hlock->instance == lock) | |
3197 | goto found_it; | |
3198 | prev_hlock = hlock; | |
3199 | } | |
3200 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3201 | return; | |
3202 | ||
3203 | found_it: | |
96645678 PZ |
3204 | cpu = smp_processor_id(); |
3205 | if (hlock->waittime_stamp) { | |
3206 | now = sched_clock(); | |
3207 | waittime = now - hlock->waittime_stamp; | |
3208 | hlock->holdtime_stamp = now; | |
3209 | } | |
f20786ff | 3210 | |
2062501a FW |
3211 | trace_lock_acquired(lock, ip, waittime); |
3212 | ||
f82b217e | 3213 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3214 | if (waittime) { |
3215 | if (hlock->read) | |
3216 | lock_time_inc(&stats->read_waittime, waittime); | |
3217 | else | |
3218 | lock_time_inc(&stats->write_waittime, waittime); | |
3219 | } | |
3220 | if (lock->cpu != cpu) | |
3221 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3222 | put_lock_stats(stats); |
96645678 PZ |
3223 | |
3224 | lock->cpu = cpu; | |
c7e78cff | 3225 | lock->ip = ip; |
f20786ff PZ |
3226 | } |
3227 | ||
3228 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3229 | { | |
3230 | unsigned long flags; | |
3231 | ||
efed792d PZ |
3232 | trace_lock_contended(lock, ip); |
3233 | ||
f20786ff PZ |
3234 | if (unlikely(!lock_stat)) |
3235 | return; | |
3236 | ||
3237 | if (unlikely(current->lockdep_recursion)) | |
3238 | return; | |
3239 | ||
3240 | raw_local_irq_save(flags); | |
3241 | check_flags(flags); | |
3242 | current->lockdep_recursion = 1; | |
3243 | __lock_contended(lock, ip); | |
3244 | current->lockdep_recursion = 0; | |
3245 | raw_local_irq_restore(flags); | |
3246 | } | |
3247 | EXPORT_SYMBOL_GPL(lock_contended); | |
3248 | ||
c7e78cff | 3249 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3250 | { |
3251 | unsigned long flags; | |
3252 | ||
3253 | if (unlikely(!lock_stat)) | |
3254 | return; | |
3255 | ||
3256 | if (unlikely(current->lockdep_recursion)) | |
3257 | return; | |
3258 | ||
3259 | raw_local_irq_save(flags); | |
3260 | check_flags(flags); | |
3261 | current->lockdep_recursion = 1; | |
c7e78cff | 3262 | __lock_acquired(lock, ip); |
f20786ff PZ |
3263 | current->lockdep_recursion = 0; |
3264 | raw_local_irq_restore(flags); | |
3265 | } | |
3266 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3267 | #endif | |
3268 | ||
fbb9ce95 IM |
3269 | /* |
3270 | * Used by the testsuite, sanitize the validator state | |
3271 | * after a simulated failure: | |
3272 | */ | |
3273 | ||
3274 | void lockdep_reset(void) | |
3275 | { | |
3276 | unsigned long flags; | |
23d95a03 | 3277 | int i; |
fbb9ce95 IM |
3278 | |
3279 | raw_local_irq_save(flags); | |
3280 | current->curr_chain_key = 0; | |
3281 | current->lockdep_depth = 0; | |
3282 | current->lockdep_recursion = 0; | |
3283 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3284 | nr_hardirq_chains = 0; | |
3285 | nr_softirq_chains = 0; | |
3286 | nr_process_chains = 0; | |
3287 | debug_locks = 1; | |
23d95a03 IM |
3288 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3289 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3290 | raw_local_irq_restore(flags); |
3291 | } | |
3292 | ||
3293 | static void zap_class(struct lock_class *class) | |
3294 | { | |
3295 | int i; | |
3296 | ||
3297 | /* | |
3298 | * Remove all dependencies this lock is | |
3299 | * involved in: | |
3300 | */ | |
3301 | for (i = 0; i < nr_list_entries; i++) { | |
3302 | if (list_entries[i].class == class) | |
3303 | list_del_rcu(&list_entries[i].entry); | |
3304 | } | |
3305 | /* | |
3306 | * Unhash the class and remove it from the all_lock_classes list: | |
3307 | */ | |
3308 | list_del_rcu(&class->hash_entry); | |
3309 | list_del_rcu(&class->lock_entry); | |
3310 | ||
8bfe0298 | 3311 | class->key = NULL; |
fbb9ce95 IM |
3312 | } |
3313 | ||
fabe874a | 3314 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3315 | { |
3316 | return addr >= start && addr < start + size; | |
3317 | } | |
3318 | ||
3319 | void lockdep_free_key_range(void *start, unsigned long size) | |
3320 | { | |
3321 | struct lock_class *class, *next; | |
3322 | struct list_head *head; | |
3323 | unsigned long flags; | |
3324 | int i; | |
5a26db5b | 3325 | int locked; |
fbb9ce95 IM |
3326 | |
3327 | raw_local_irq_save(flags); | |
5a26db5b | 3328 | locked = graph_lock(); |
fbb9ce95 IM |
3329 | |
3330 | /* | |
3331 | * Unhash all classes that were created by this module: | |
3332 | */ | |
3333 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3334 | head = classhash_table + i; | |
3335 | if (list_empty(head)) | |
3336 | continue; | |
fabe874a | 3337 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3338 | if (within(class->key, start, size)) |
3339 | zap_class(class); | |
fabe874a AV |
3340 | else if (within(class->name, start, size)) |
3341 | zap_class(class); | |
3342 | } | |
fbb9ce95 IM |
3343 | } |
3344 | ||
5a26db5b NP |
3345 | if (locked) |
3346 | graph_unlock(); | |
fbb9ce95 IM |
3347 | raw_local_irq_restore(flags); |
3348 | } | |
3349 | ||
3350 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3351 | { | |
d6d897ce | 3352 | struct lock_class *class, *next; |
fbb9ce95 IM |
3353 | struct list_head *head; |
3354 | unsigned long flags; | |
3355 | int i, j; | |
5a26db5b | 3356 | int locked; |
fbb9ce95 IM |
3357 | |
3358 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3359 | |
3360 | /* | |
d6d897ce IM |
3361 | * Remove all classes this lock might have: |
3362 | */ | |
3363 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3364 | /* | |
3365 | * If the class exists we look it up and zap it: | |
3366 | */ | |
3367 | class = look_up_lock_class(lock, j); | |
3368 | if (class) | |
3369 | zap_class(class); | |
3370 | } | |
3371 | /* | |
3372 | * Debug check: in the end all mapped classes should | |
3373 | * be gone. | |
fbb9ce95 | 3374 | */ |
5a26db5b | 3375 | locked = graph_lock(); |
fbb9ce95 IM |
3376 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3377 | head = classhash_table + i; | |
3378 | if (list_empty(head)) | |
3379 | continue; | |
3380 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3381 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3382 | if (debug_locks_off_graph_unlock()) |
3383 | WARN_ON(1); | |
d6d897ce | 3384 | goto out_restore; |
fbb9ce95 IM |
3385 | } |
3386 | } | |
3387 | } | |
5a26db5b NP |
3388 | if (locked) |
3389 | graph_unlock(); | |
d6d897ce IM |
3390 | |
3391 | out_restore: | |
fbb9ce95 IM |
3392 | raw_local_irq_restore(flags); |
3393 | } | |
3394 | ||
1499993c | 3395 | void lockdep_init(void) |
fbb9ce95 IM |
3396 | { |
3397 | int i; | |
3398 | ||
3399 | /* | |
3400 | * Some architectures have their own start_kernel() | |
3401 | * code which calls lockdep_init(), while we also | |
3402 | * call lockdep_init() from the start_kernel() itself, | |
3403 | * and we want to initialize the hashes only once: | |
3404 | */ | |
3405 | if (lockdep_initialized) | |
3406 | return; | |
3407 | ||
3408 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3409 | INIT_LIST_HEAD(classhash_table + i); | |
3410 | ||
3411 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3412 | INIT_LIST_HEAD(chainhash_table + i); | |
3413 | ||
3414 | lockdep_initialized = 1; | |
3415 | } | |
3416 | ||
3417 | void __init lockdep_info(void) | |
3418 | { | |
3419 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3420 | ||
b0788caf | 3421 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3422 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3423 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3424 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3425 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3426 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3427 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3428 | ||
3429 | printk(" memory used by lock dependency info: %lu kB\n", | |
3430 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3431 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3432 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3433 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
3434 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
3435 | ||
3436 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3437 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3438 | ||
3439 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3440 | if (lockdep_init_error) { |
3441 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3442 | printk("Call stack leading to lockdep invocation was:\n"); | |
3443 | print_stack_trace(&lockdep_init_trace, 0); | |
3444 | } | |
fbb9ce95 IM |
3445 | #endif |
3446 | } | |
3447 | ||
fbb9ce95 IM |
3448 | static void |
3449 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3450 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3451 | { |
3452 | if (!debug_locks_off()) | |
3453 | return; | |
3454 | if (debug_locks_silent) | |
3455 | return; | |
3456 | ||
3457 | printk("\n=========================\n"); | |
3458 | printk( "[ BUG: held lock freed! ]\n"); | |
3459 | printk( "-------------------------\n"); | |
3460 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3461 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3462 | print_lock(hlock); |
fbb9ce95 IM |
3463 | lockdep_print_held_locks(curr); |
3464 | ||
3465 | printk("\nstack backtrace:\n"); | |
3466 | dump_stack(); | |
3467 | } | |
3468 | ||
54561783 ON |
3469 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3470 | const void* lock_from, unsigned long lock_len) | |
3471 | { | |
3472 | return lock_from + lock_len <= mem_from || | |
3473 | mem_from + mem_len <= lock_from; | |
3474 | } | |
3475 | ||
fbb9ce95 IM |
3476 | /* |
3477 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3478 | * is destroyed or reinitialized - this code checks whether there is | |
3479 | * any held lock in the memory range of <from> to <to>: | |
3480 | */ | |
3481 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3482 | { | |
fbb9ce95 IM |
3483 | struct task_struct *curr = current; |
3484 | struct held_lock *hlock; | |
3485 | unsigned long flags; | |
3486 | int i; | |
3487 | ||
3488 | if (unlikely(!debug_locks)) | |
3489 | return; | |
3490 | ||
3491 | local_irq_save(flags); | |
3492 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3493 | hlock = curr->held_locks + i; | |
3494 | ||
54561783 ON |
3495 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3496 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3497 | continue; |
3498 | ||
54561783 | 3499 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3500 | break; |
3501 | } | |
3502 | local_irq_restore(flags); | |
3503 | } | |
ed07536e | 3504 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3505 | |
3506 | static void print_held_locks_bug(struct task_struct *curr) | |
3507 | { | |
3508 | if (!debug_locks_off()) | |
3509 | return; | |
3510 | if (debug_locks_silent) | |
3511 | return; | |
3512 | ||
3513 | printk("\n=====================================\n"); | |
3514 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3515 | printk( "-------------------------------------\n"); | |
3516 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3517 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3518 | lockdep_print_held_locks(curr); |
3519 | ||
3520 | printk("\nstack backtrace:\n"); | |
3521 | dump_stack(); | |
3522 | } | |
3523 | ||
3524 | void debug_check_no_locks_held(struct task_struct *task) | |
3525 | { | |
3526 | if (unlikely(task->lockdep_depth > 0)) | |
3527 | print_held_locks_bug(task); | |
3528 | } | |
3529 | ||
3530 | void debug_show_all_locks(void) | |
3531 | { | |
3532 | struct task_struct *g, *p; | |
3533 | int count = 10; | |
3534 | int unlock = 1; | |
3535 | ||
9c35dd7f JP |
3536 | if (unlikely(!debug_locks)) { |
3537 | printk("INFO: lockdep is turned off.\n"); | |
3538 | return; | |
3539 | } | |
fbb9ce95 IM |
3540 | printk("\nShowing all locks held in the system:\n"); |
3541 | ||
3542 | /* | |
3543 | * Here we try to get the tasklist_lock as hard as possible, | |
3544 | * if not successful after 2 seconds we ignore it (but keep | |
3545 | * trying). This is to enable a debug printout even if a | |
3546 | * tasklist_lock-holding task deadlocks or crashes. | |
3547 | */ | |
3548 | retry: | |
3549 | if (!read_trylock(&tasklist_lock)) { | |
3550 | if (count == 10) | |
3551 | printk("hm, tasklist_lock locked, retrying... "); | |
3552 | if (count) { | |
3553 | count--; | |
3554 | printk(" #%d", 10-count); | |
3555 | mdelay(200); | |
3556 | goto retry; | |
3557 | } | |
3558 | printk(" ignoring it.\n"); | |
3559 | unlock = 0; | |
46fec7ac | 3560 | } else { |
3561 | if (count != 10) | |
3562 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3563 | } |
fbb9ce95 IM |
3564 | |
3565 | do_each_thread(g, p) { | |
85684873 IM |
3566 | /* |
3567 | * It's not reliable to print a task's held locks | |
3568 | * if it's not sleeping (or if it's not the current | |
3569 | * task): | |
3570 | */ | |
3571 | if (p->state == TASK_RUNNING && p != current) | |
3572 | continue; | |
fbb9ce95 IM |
3573 | if (p->lockdep_depth) |
3574 | lockdep_print_held_locks(p); | |
3575 | if (!unlock) | |
3576 | if (read_trylock(&tasklist_lock)) | |
3577 | unlock = 1; | |
3578 | } while_each_thread(g, p); | |
3579 | ||
3580 | printk("\n"); | |
3581 | printk("=============================================\n\n"); | |
3582 | ||
3583 | if (unlock) | |
3584 | read_unlock(&tasklist_lock); | |
3585 | } | |
fbb9ce95 IM |
3586 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3587 | ||
82a1fcb9 IM |
3588 | /* |
3589 | * Careful: only use this function if you are sure that | |
3590 | * the task cannot run in parallel! | |
3591 | */ | |
3592 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3593 | { |
9c35dd7f JP |
3594 | if (unlikely(!debug_locks)) { |
3595 | printk("INFO: lockdep is turned off.\n"); | |
3596 | return; | |
3597 | } | |
fbb9ce95 IM |
3598 | lockdep_print_held_locks(task); |
3599 | } | |
82a1fcb9 IM |
3600 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3601 | ||
3602 | void debug_show_held_locks(struct task_struct *task) | |
3603 | { | |
3604 | __debug_show_held_locks(task); | |
3605 | } | |
fbb9ce95 | 3606 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3607 | |
3608 | void lockdep_sys_exit(void) | |
3609 | { | |
3610 | struct task_struct *curr = current; | |
3611 | ||
3612 | if (unlikely(curr->lockdep_depth)) { | |
3613 | if (!debug_locks_off()) | |
3614 | return; | |
3615 | printk("\n================================================\n"); | |
3616 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3617 | printk( "------------------------------------------------\n"); | |
3618 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3619 | curr->comm, curr->pid); | |
3620 | lockdep_print_held_locks(curr); | |
3621 | } | |
3622 | } |