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 | * | |
8 | * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
9 | * | |
10 | * this code maps all the lock dependencies as they occur in a live kernel | |
11 | * and will warn about the following classes of locking bugs: | |
12 | * | |
13 | * - lock inversion scenarios | |
14 | * - circular lock dependencies | |
15 | * - hardirq/softirq safe/unsafe locking bugs | |
16 | * | |
17 | * Bugs are reported even if the current locking scenario does not cause | |
18 | * any deadlock at this point. | |
19 | * | |
20 | * I.e. if anytime in the past two locks were taken in a different order, | |
21 | * even if it happened for another task, even if those were different | |
22 | * locks (but of the same class as this lock), this code will detect it. | |
23 | * | |
24 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
25 | * mapping lock dependencies runtime. | |
26 | */ | |
27 | #include <linux/mutex.h> | |
28 | #include <linux/sched.h> | |
29 | #include <linux/delay.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/proc_fs.h> | |
32 | #include <linux/seq_file.h> | |
33 | #include <linux/spinlock.h> | |
34 | #include <linux/kallsyms.h> | |
35 | #include <linux/interrupt.h> | |
36 | #include <linux/stacktrace.h> | |
37 | #include <linux/debug_locks.h> | |
38 | #include <linux/irqflags.h> | |
99de055a | 39 | #include <linux/utsname.h> |
fbb9ce95 IM |
40 | |
41 | #include <asm/sections.h> | |
42 | ||
43 | #include "lockdep_internals.h" | |
44 | ||
45 | /* | |
74c383f1 IM |
46 | * lockdep_lock: protects the lockdep graph, the hashes and the |
47 | * class/list/hash allocators. | |
fbb9ce95 IM |
48 | * |
49 | * This is one of the rare exceptions where it's justified | |
50 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 51 | * code to recurse back into the lockdep code... |
fbb9ce95 | 52 | */ |
74c383f1 IM |
53 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
54 | ||
55 | static int graph_lock(void) | |
56 | { | |
57 | __raw_spin_lock(&lockdep_lock); | |
58 | /* | |
59 | * Make sure that if another CPU detected a bug while | |
60 | * walking the graph we dont change it (while the other | |
61 | * CPU is busy printing out stuff with the graph lock | |
62 | * dropped already) | |
63 | */ | |
64 | if (!debug_locks) { | |
65 | __raw_spin_unlock(&lockdep_lock); | |
66 | return 0; | |
67 | } | |
68 | return 1; | |
69 | } | |
70 | ||
71 | static inline int graph_unlock(void) | |
72 | { | |
381a2292 JP |
73 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
74 | return DEBUG_LOCKS_WARN_ON(1); | |
75 | ||
74c383f1 IM |
76 | __raw_spin_unlock(&lockdep_lock); |
77 | return 0; | |
78 | } | |
79 | ||
80 | /* | |
81 | * Turn lock debugging off and return with 0 if it was off already, | |
82 | * and also release the graph lock: | |
83 | */ | |
84 | static inline int debug_locks_off_graph_unlock(void) | |
85 | { | |
86 | int ret = debug_locks_off(); | |
87 | ||
88 | __raw_spin_unlock(&lockdep_lock); | |
89 | ||
90 | return ret; | |
91 | } | |
fbb9ce95 IM |
92 | |
93 | static int lockdep_initialized; | |
94 | ||
95 | unsigned long nr_list_entries; | |
96 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; | |
97 | ||
fbb9ce95 IM |
98 | /* |
99 | * All data structures here are protected by the global debug_lock. | |
100 | * | |
101 | * Mutex key structs only get allocated, once during bootup, and never | |
102 | * get freed - this significantly simplifies the debugging code. | |
103 | */ | |
104 | unsigned long nr_lock_classes; | |
105 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
106 | ||
107 | /* | |
108 | * We keep a global list of all lock classes. The list only grows, | |
109 | * never shrinks. The list is only accessed with the lockdep | |
110 | * spinlock lock held. | |
111 | */ | |
112 | LIST_HEAD(all_lock_classes); | |
113 | ||
114 | /* | |
115 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
116 | */ | |
117 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
118 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
119 | #define CLASSHASH_MASK (CLASSHASH_SIZE - 1) | |
120 | #define __classhashfn(key) ((((unsigned long)key >> CLASSHASH_BITS) + (unsigned long)key) & CLASSHASH_MASK) | |
121 | #define classhashentry(key) (classhash_table + __classhashfn((key))) | |
122 | ||
123 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
124 | ||
fbb9ce95 IM |
125 | /* |
126 | * We put the lock dependency chains into a hash-table as well, to cache | |
127 | * their existence: | |
128 | */ | |
129 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
130 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
131 | #define CHAINHASH_MASK (CHAINHASH_SIZE - 1) | |
132 | #define __chainhashfn(chain) \ | |
133 | (((chain >> CHAINHASH_BITS) + chain) & CHAINHASH_MASK) | |
134 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) | |
135 | ||
136 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
137 | ||
138 | /* | |
139 | * The hash key of the lock dependency chains is a hash itself too: | |
140 | * it's a hash of all locks taken up to that lock, including that lock. | |
141 | * It's a 64-bit hash, because it's important for the keys to be | |
142 | * unique. | |
143 | */ | |
144 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
145 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
146 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
147 | (key2)) |
148 | ||
149 | void lockdep_off(void) | |
150 | { | |
151 | current->lockdep_recursion++; | |
152 | } | |
153 | ||
154 | EXPORT_SYMBOL(lockdep_off); | |
155 | ||
156 | void lockdep_on(void) | |
157 | { | |
158 | current->lockdep_recursion--; | |
159 | } | |
160 | ||
161 | EXPORT_SYMBOL(lockdep_on); | |
162 | ||
fbb9ce95 IM |
163 | /* |
164 | * Debugging switches: | |
165 | */ | |
166 | ||
167 | #define VERBOSE 0 | |
33e94e96 | 168 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
169 | |
170 | #if VERBOSE | |
171 | # define HARDIRQ_VERBOSE 1 | |
172 | # define SOFTIRQ_VERBOSE 1 | |
173 | #else | |
174 | # define HARDIRQ_VERBOSE 0 | |
175 | # define SOFTIRQ_VERBOSE 0 | |
176 | #endif | |
177 | ||
178 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE | |
179 | /* | |
180 | * Quick filtering for interesting events: | |
181 | */ | |
182 | static int class_filter(struct lock_class *class) | |
183 | { | |
f9829cce AK |
184 | #if 0 |
185 | /* Example */ | |
fbb9ce95 | 186 | if (class->name_version == 1 && |
f9829cce | 187 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
188 | return 1; |
189 | if (class->name_version == 1 && | |
f9829cce | 190 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 191 | return 1; |
f9829cce | 192 | #endif |
a6640897 IM |
193 | /* Filter everything else. 1 would be to allow everything else */ |
194 | return 0; | |
fbb9ce95 IM |
195 | } |
196 | #endif | |
197 | ||
198 | static int verbose(struct lock_class *class) | |
199 | { | |
200 | #if VERBOSE | |
201 | return class_filter(class); | |
202 | #endif | |
203 | return 0; | |
204 | } | |
205 | ||
fbb9ce95 IM |
206 | /* |
207 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 208 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
209 | */ |
210 | unsigned long nr_stack_trace_entries; | |
211 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
212 | ||
213 | static int save_trace(struct stack_trace *trace) | |
214 | { | |
215 | trace->nr_entries = 0; | |
216 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
217 | trace->entries = stack_trace + nr_stack_trace_entries; | |
218 | ||
5a1b3999 | 219 | trace->skip = 3; |
5a1b3999 | 220 | |
ab1b6f03 | 221 | save_stack_trace(trace); |
fbb9ce95 IM |
222 | |
223 | trace->max_entries = trace->nr_entries; | |
224 | ||
225 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
226 | |
227 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
228 | if (!debug_locks_off_graph_unlock()) |
229 | return 0; | |
230 | ||
231 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
232 | printk("turning off the locking correctness validator.\n"); | |
233 | dump_stack(); | |
234 | ||
fbb9ce95 IM |
235 | return 0; |
236 | } | |
237 | ||
238 | return 1; | |
239 | } | |
240 | ||
241 | unsigned int nr_hardirq_chains; | |
242 | unsigned int nr_softirq_chains; | |
243 | unsigned int nr_process_chains; | |
244 | unsigned int max_lockdep_depth; | |
245 | unsigned int max_recursion_depth; | |
246 | ||
247 | #ifdef CONFIG_DEBUG_LOCKDEP | |
248 | /* | |
249 | * We cannot printk in early bootup code. Not even early_printk() | |
250 | * might work. So we mark any initialization errors and printk | |
251 | * about it later on, in lockdep_info(). | |
252 | */ | |
253 | static int lockdep_init_error; | |
254 | ||
255 | /* | |
256 | * Various lockdep statistics: | |
257 | */ | |
258 | atomic_t chain_lookup_hits; | |
259 | atomic_t chain_lookup_misses; | |
260 | atomic_t hardirqs_on_events; | |
261 | atomic_t hardirqs_off_events; | |
262 | atomic_t redundant_hardirqs_on; | |
263 | atomic_t redundant_hardirqs_off; | |
264 | atomic_t softirqs_on_events; | |
265 | atomic_t softirqs_off_events; | |
266 | atomic_t redundant_softirqs_on; | |
267 | atomic_t redundant_softirqs_off; | |
268 | atomic_t nr_unused_locks; | |
269 | atomic_t nr_cyclic_checks; | |
270 | atomic_t nr_cyclic_check_recursions; | |
271 | atomic_t nr_find_usage_forwards_checks; | |
272 | atomic_t nr_find_usage_forwards_recursions; | |
273 | atomic_t nr_find_usage_backwards_checks; | |
274 | atomic_t nr_find_usage_backwards_recursions; | |
275 | # define debug_atomic_inc(ptr) atomic_inc(ptr) | |
276 | # define debug_atomic_dec(ptr) atomic_dec(ptr) | |
277 | # define debug_atomic_read(ptr) atomic_read(ptr) | |
278 | #else | |
279 | # define debug_atomic_inc(ptr) do { } while (0) | |
280 | # define debug_atomic_dec(ptr) do { } while (0) | |
281 | # define debug_atomic_read(ptr) 0 | |
282 | #endif | |
283 | ||
284 | /* | |
285 | * Locking printouts: | |
286 | */ | |
287 | ||
288 | static const char *usage_str[] = | |
289 | { | |
290 | [LOCK_USED] = "initial-use ", | |
291 | [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W", | |
292 | [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W", | |
293 | [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W", | |
294 | [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W", | |
295 | [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R", | |
296 | [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R", | |
297 | [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R", | |
298 | [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R", | |
299 | }; | |
300 | ||
301 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
302 | { | |
ffb45122 | 303 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
304 | } |
305 | ||
306 | void | |
307 | get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4) | |
308 | { | |
309 | *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.'; | |
310 | ||
311 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) | |
312 | *c1 = '+'; | |
313 | else | |
314 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) | |
315 | *c1 = '-'; | |
316 | ||
317 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) | |
318 | *c2 = '+'; | |
319 | else | |
320 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) | |
321 | *c2 = '-'; | |
322 | ||
323 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
324 | *c3 = '-'; | |
325 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { | |
326 | *c3 = '+'; | |
327 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
328 | *c3 = '?'; | |
329 | } | |
330 | ||
331 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
332 | *c4 = '-'; | |
333 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { | |
334 | *c4 = '+'; | |
335 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
336 | *c4 = '?'; | |
337 | } | |
338 | } | |
339 | ||
340 | static void print_lock_name(struct lock_class *class) | |
341 | { | |
9281acea | 342 | char str[KSYM_NAME_LEN], c1, c2, c3, c4; |
fbb9ce95 IM |
343 | const char *name; |
344 | ||
345 | get_usage_chars(class, &c1, &c2, &c3, &c4); | |
346 | ||
347 | name = class->name; | |
348 | if (!name) { | |
349 | name = __get_key_name(class->key, str); | |
350 | printk(" (%s", name); | |
351 | } else { | |
352 | printk(" (%s", name); | |
353 | if (class->name_version > 1) | |
354 | printk("#%d", class->name_version); | |
355 | if (class->subclass) | |
356 | printk("/%d", class->subclass); | |
357 | } | |
358 | printk("){%c%c%c%c}", c1, c2, c3, c4); | |
359 | } | |
360 | ||
361 | static void print_lockdep_cache(struct lockdep_map *lock) | |
362 | { | |
363 | const char *name; | |
9281acea | 364 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
365 | |
366 | name = lock->name; | |
367 | if (!name) | |
368 | name = __get_key_name(lock->key->subkeys, str); | |
369 | ||
370 | printk("%s", name); | |
371 | } | |
372 | ||
373 | static void print_lock(struct held_lock *hlock) | |
374 | { | |
375 | print_lock_name(hlock->class); | |
376 | printk(", at: "); | |
377 | print_ip_sym(hlock->acquire_ip); | |
378 | } | |
379 | ||
380 | static void lockdep_print_held_locks(struct task_struct *curr) | |
381 | { | |
382 | int i, depth = curr->lockdep_depth; | |
383 | ||
384 | if (!depth) { | |
385 | printk("no locks held by %s/%d.\n", curr->comm, curr->pid); | |
386 | return; | |
387 | } | |
388 | printk("%d lock%s held by %s/%d:\n", | |
389 | depth, depth > 1 ? "s" : "", curr->comm, curr->pid); | |
390 | ||
391 | for (i = 0; i < depth; i++) { | |
392 | printk(" #%d: ", i); | |
393 | print_lock(curr->held_locks + i); | |
394 | } | |
395 | } | |
fbb9ce95 IM |
396 | |
397 | static void print_lock_class_header(struct lock_class *class, int depth) | |
398 | { | |
399 | int bit; | |
400 | ||
f9829cce | 401 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
402 | print_lock_name(class); |
403 | printk(" ops: %lu", class->ops); | |
404 | printk(" {\n"); | |
405 | ||
406 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
407 | if (class->usage_mask & (1 << bit)) { | |
408 | int len = depth; | |
409 | ||
f9829cce | 410 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
411 | len += printk(" at:\n"); |
412 | print_stack_trace(class->usage_traces + bit, len); | |
413 | } | |
414 | } | |
f9829cce | 415 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 416 | |
f9829cce | 417 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
418 | print_ip_sym((unsigned long)class->key); |
419 | } | |
420 | ||
421 | /* | |
422 | * printk all lock dependencies starting at <entry>: | |
423 | */ | |
424 | static void print_lock_dependencies(struct lock_class *class, int depth) | |
425 | { | |
426 | struct lock_list *entry; | |
427 | ||
428 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) | |
429 | return; | |
430 | ||
431 | print_lock_class_header(class, depth); | |
432 | ||
433 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
434 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
435 | return; | |
436 | ||
fbb9ce95 IM |
437 | print_lock_dependencies(entry->class, depth + 1); |
438 | ||
f9829cce | 439 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
440 | print_stack_trace(&entry->trace, 2); |
441 | printk("\n"); | |
442 | } | |
443 | } | |
444 | ||
8e18257d PZ |
445 | static void print_kernel_version(void) |
446 | { | |
447 | printk("%s %.*s\n", init_utsname()->release, | |
448 | (int)strcspn(init_utsname()->version, " "), | |
449 | init_utsname()->version); | |
450 | } | |
451 | ||
452 | static int very_verbose(struct lock_class *class) | |
453 | { | |
454 | #if VERY_VERBOSE | |
455 | return class_filter(class); | |
456 | #endif | |
457 | return 0; | |
458 | } | |
459 | ||
fbb9ce95 | 460 | /* |
8e18257d | 461 | * Is this the address of a static object: |
fbb9ce95 | 462 | */ |
8e18257d | 463 | static int static_obj(void *obj) |
fbb9ce95 | 464 | { |
8e18257d PZ |
465 | unsigned long start = (unsigned long) &_stext, |
466 | end = (unsigned long) &_end, | |
467 | addr = (unsigned long) obj; | |
468 | #ifdef CONFIG_SMP | |
469 | int i; | |
470 | #endif | |
471 | ||
fbb9ce95 | 472 | /* |
8e18257d | 473 | * static variable? |
fbb9ce95 | 474 | */ |
8e18257d PZ |
475 | if ((addr >= start) && (addr < end)) |
476 | return 1; | |
fbb9ce95 | 477 | |
8e18257d | 478 | #ifdef CONFIG_SMP |
fbb9ce95 | 479 | /* |
8e18257d | 480 | * percpu var? |
fbb9ce95 | 481 | */ |
8e18257d PZ |
482 | for_each_possible_cpu(i) { |
483 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
484 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
485 | + per_cpu_offset(i); | |
fbb9ce95 | 486 | |
8e18257d PZ |
487 | if ((addr >= start) && (addr < end)) |
488 | return 1; | |
489 | } | |
ca58abcb | 490 | #endif |
fbb9ce95 | 491 | |
8e18257d PZ |
492 | /* |
493 | * module var? | |
494 | */ | |
495 | return is_module_address(addr); | |
99de055a DJ |
496 | } |
497 | ||
fbb9ce95 | 498 | /* |
8e18257d PZ |
499 | * To make lock name printouts unique, we calculate a unique |
500 | * class->name_version generation counter: | |
fbb9ce95 | 501 | */ |
8e18257d | 502 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 503 | { |
8e18257d PZ |
504 | struct lock_class *class; |
505 | int count = 0; | |
fbb9ce95 | 506 | |
8e18257d | 507 | if (!new_class->name) |
fbb9ce95 IM |
508 | return 0; |
509 | ||
8e18257d PZ |
510 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
511 | if (new_class->key - new_class->subclass == class->key) | |
512 | return class->name_version; | |
513 | if (class->name && !strcmp(class->name, new_class->name)) | |
514 | count = max(count, class->name_version); | |
515 | } | |
fbb9ce95 | 516 | |
8e18257d | 517 | return count + 1; |
fbb9ce95 IM |
518 | } |
519 | ||
8e18257d PZ |
520 | /* |
521 | * Register a lock's class in the hash-table, if the class is not present | |
522 | * yet. Otherwise we look it up. We cache the result in the lock object | |
523 | * itself, so actual lookup of the hash should be once per lock object. | |
524 | */ | |
525 | static inline struct lock_class * | |
526 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 527 | { |
8e18257d PZ |
528 | struct lockdep_subclass_key *key; |
529 | struct list_head *hash_head; | |
530 | struct lock_class *class; | |
fbb9ce95 | 531 | |
8e18257d PZ |
532 | #ifdef CONFIG_DEBUG_LOCKDEP |
533 | /* | |
534 | * If the architecture calls into lockdep before initializing | |
535 | * the hashes then we'll warn about it later. (we cannot printk | |
536 | * right now) | |
537 | */ | |
538 | if (unlikely(!lockdep_initialized)) { | |
539 | lockdep_init(); | |
540 | lockdep_init_error = 1; | |
541 | } | |
542 | #endif | |
fbb9ce95 | 543 | |
8e18257d PZ |
544 | /* |
545 | * Static locks do not have their class-keys yet - for them the key | |
546 | * is the lock object itself: | |
547 | */ | |
548 | if (unlikely(!lock->key)) | |
549 | lock->key = (void *)lock; | |
fbb9ce95 | 550 | |
8e18257d PZ |
551 | /* |
552 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
553 | * lock_class_key variable is passed in through the mutex_init() | |
554 | * (or spin_lock_init()) call - which acts as the key. For static | |
555 | * locks we use the lock object itself as the key. | |
556 | */ | |
557 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class)); | |
fbb9ce95 | 558 | |
8e18257d | 559 | key = lock->key->subkeys + subclass; |
ca268c69 | 560 | |
8e18257d | 561 | hash_head = classhashentry(key); |
74c383f1 | 562 | |
8e18257d PZ |
563 | /* |
564 | * We can walk the hash lockfree, because the hash only | |
565 | * grows, and we are careful when adding entries to the end: | |
566 | */ | |
567 | list_for_each_entry(class, hash_head, hash_entry) | |
568 | if (class->key == key) | |
569 | return class; | |
fbb9ce95 | 570 | |
8e18257d | 571 | return NULL; |
fbb9ce95 IM |
572 | } |
573 | ||
574 | /* | |
8e18257d PZ |
575 | * Register a lock's class in the hash-table, if the class is not present |
576 | * yet. Otherwise we look it up. We cache the result in the lock object | |
577 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 578 | */ |
8e18257d PZ |
579 | static inline struct lock_class * |
580 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 581 | { |
8e18257d PZ |
582 | struct lockdep_subclass_key *key; |
583 | struct list_head *hash_head; | |
584 | struct lock_class *class; | |
585 | unsigned long flags; | |
586 | ||
587 | class = look_up_lock_class(lock, subclass); | |
588 | if (likely(class)) | |
589 | return class; | |
590 | ||
591 | /* | |
592 | * Debug-check: all keys must be persistent! | |
593 | */ | |
594 | if (!static_obj(lock->key)) { | |
595 | debug_locks_off(); | |
596 | printk("INFO: trying to register non-static key.\n"); | |
597 | printk("the code is fine but needs lockdep annotation.\n"); | |
598 | printk("turning off the locking correctness validator.\n"); | |
599 | dump_stack(); | |
600 | ||
601 | return NULL; | |
602 | } | |
603 | ||
604 | key = lock->key->subkeys + subclass; | |
605 | hash_head = classhashentry(key); | |
606 | ||
607 | raw_local_irq_save(flags); | |
608 | if (!graph_lock()) { | |
609 | raw_local_irq_restore(flags); | |
610 | return NULL; | |
611 | } | |
612 | /* | |
613 | * We have to do the hash-walk again, to avoid races | |
614 | * with another CPU: | |
615 | */ | |
616 | list_for_each_entry(class, hash_head, hash_entry) | |
617 | if (class->key == key) | |
618 | goto out_unlock_set; | |
619 | /* | |
620 | * Allocate a new key from the static array, and add it to | |
621 | * the hash: | |
622 | */ | |
623 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
624 | if (!debug_locks_off_graph_unlock()) { | |
625 | raw_local_irq_restore(flags); | |
626 | return NULL; | |
627 | } | |
628 | raw_local_irq_restore(flags); | |
629 | ||
630 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
631 | printk("turning off the locking correctness validator.\n"); | |
632 | return NULL; | |
633 | } | |
634 | class = lock_classes + nr_lock_classes++; | |
635 | debug_atomic_inc(&nr_unused_locks); | |
636 | class->key = key; | |
637 | class->name = lock->name; | |
638 | class->subclass = subclass; | |
639 | INIT_LIST_HEAD(&class->lock_entry); | |
640 | INIT_LIST_HEAD(&class->locks_before); | |
641 | INIT_LIST_HEAD(&class->locks_after); | |
642 | class->name_version = count_matching_names(class); | |
643 | /* | |
644 | * We use RCU's safe list-add method to make | |
645 | * parallel walking of the hash-list safe: | |
646 | */ | |
647 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
648 | ||
649 | if (verbose(class)) { | |
650 | graph_unlock(); | |
651 | raw_local_irq_restore(flags); | |
652 | ||
653 | printk("\nnew class %p: %s", class->key, class->name); | |
654 | if (class->name_version > 1) | |
655 | printk("#%d", class->name_version); | |
656 | printk("\n"); | |
657 | dump_stack(); | |
658 | ||
659 | raw_local_irq_save(flags); | |
660 | if (!graph_lock()) { | |
661 | raw_local_irq_restore(flags); | |
662 | return NULL; | |
663 | } | |
664 | } | |
665 | out_unlock_set: | |
666 | graph_unlock(); | |
667 | raw_local_irq_restore(flags); | |
668 | ||
669 | if (!subclass || force) | |
670 | lock->class_cache = class; | |
671 | ||
672 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
673 | return NULL; | |
674 | ||
675 | return class; | |
676 | } | |
677 | ||
678 | #ifdef CONFIG_PROVE_LOCKING | |
679 | /* | |
680 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
681 | * with NULL on failure) | |
682 | */ | |
683 | static struct lock_list *alloc_list_entry(void) | |
684 | { | |
685 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
686 | if (!debug_locks_off_graph_unlock()) | |
687 | return NULL; | |
688 | ||
689 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
690 | printk("turning off the locking correctness validator.\n"); | |
691 | return NULL; | |
692 | } | |
693 | return list_entries + nr_list_entries++; | |
694 | } | |
695 | ||
696 | /* | |
697 | * Add a new dependency to the head of the list: | |
698 | */ | |
699 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
700 | struct list_head *head, unsigned long ip, int distance) | |
701 | { | |
702 | struct lock_list *entry; | |
703 | /* | |
704 | * Lock not present yet - get a new dependency struct and | |
705 | * add it to the list: | |
706 | */ | |
707 | entry = alloc_list_entry(); | |
708 | if (!entry) | |
709 | return 0; | |
710 | ||
711 | entry->class = this; | |
712 | entry->distance = distance; | |
713 | if (!save_trace(&entry->trace)) | |
714 | return 0; | |
715 | ||
716 | /* | |
717 | * Since we never remove from the dependency list, the list can | |
718 | * be walked lockless by other CPUs, it's only allocation | |
719 | * that must be protected by the spinlock. But this also means | |
720 | * we must make new entries visible only once writes to the | |
721 | * entry become visible - hence the RCU op: | |
722 | */ | |
723 | list_add_tail_rcu(&entry->entry, head); | |
724 | ||
725 | return 1; | |
726 | } | |
727 | ||
728 | /* | |
729 | * Recursive, forwards-direction lock-dependency checking, used for | |
730 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
731 | * checking. | |
732 | * | |
733 | * (to keep the stackframe of the recursive functions small we | |
734 | * use these global variables, and we also mark various helper | |
735 | * functions as noinline.) | |
736 | */ | |
737 | static struct held_lock *check_source, *check_target; | |
738 | ||
739 | /* | |
740 | * Print a dependency chain entry (this is only done when a deadlock | |
741 | * has been detected): | |
742 | */ | |
743 | static noinline int | |
744 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |
745 | { | |
746 | if (debug_locks_silent) | |
747 | return 0; | |
748 | printk("\n-> #%u", depth); | |
749 | print_lock_name(target->class); | |
750 | printk(":\n"); | |
751 | print_stack_trace(&target->trace, 6); | |
752 | ||
753 | return 0; | |
754 | } | |
755 | ||
756 | /* | |
757 | * When a circular dependency is detected, print the | |
758 | * header first: | |
759 | */ | |
760 | static noinline int | |
761 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) | |
762 | { | |
763 | struct task_struct *curr = current; | |
764 | ||
765 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
766 | return 0; | |
767 | ||
768 | printk("\n=======================================================\n"); | |
769 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
770 | print_kernel_version(); | |
771 | printk( "-------------------------------------------------------\n"); | |
772 | printk("%s/%d is trying to acquire lock:\n", | |
773 | curr->comm, curr->pid); | |
774 | print_lock(check_source); | |
775 | printk("\nbut task is already holding lock:\n"); | |
776 | print_lock(check_target); | |
777 | printk("\nwhich lock already depends on the new lock.\n\n"); | |
778 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
779 | ||
780 | print_circular_bug_entry(entry, depth); | |
781 | ||
782 | return 0; | |
783 | } | |
784 | ||
785 | static noinline int print_circular_bug_tail(void) | |
786 | { | |
787 | struct task_struct *curr = current; | |
788 | struct lock_list this; | |
789 | ||
790 | if (debug_locks_silent) | |
791 | return 0; | |
792 | ||
793 | this.class = check_source->class; | |
794 | if (!save_trace(&this.trace)) | |
795 | return 0; | |
796 | ||
797 | print_circular_bug_entry(&this, 0); | |
798 | ||
799 | printk("\nother info that might help us debug this:\n\n"); | |
800 | lockdep_print_held_locks(curr); | |
801 | ||
802 | printk("\nstack backtrace:\n"); | |
803 | dump_stack(); | |
804 | ||
805 | return 0; | |
806 | } | |
807 | ||
808 | #define RECURSION_LIMIT 40 | |
809 | ||
810 | static int noinline print_infinite_recursion_bug(void) | |
811 | { | |
812 | if (!debug_locks_off_graph_unlock()) | |
813 | return 0; | |
814 | ||
815 | WARN_ON(1); | |
816 | ||
817 | return 0; | |
818 | } | |
819 | ||
820 | /* | |
821 | * Prove that the dependency graph starting at <entry> can not | |
822 | * lead to <target>. Print an error and return 0 if it does. | |
823 | */ | |
824 | static noinline int | |
825 | check_noncircular(struct lock_class *source, unsigned int depth) | |
826 | { | |
827 | struct lock_list *entry; | |
828 | ||
829 | debug_atomic_inc(&nr_cyclic_check_recursions); | |
830 | if (depth > max_recursion_depth) | |
fbb9ce95 | 831 | max_recursion_depth = depth; |
ca268c69 | 832 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
833 | return print_infinite_recursion_bug(); |
834 | /* | |
835 | * Check this lock's dependency list: | |
836 | */ | |
837 | list_for_each_entry(entry, &source->locks_after, entry) { | |
838 | if (entry->class == check_target->class) | |
839 | return print_circular_bug_header(entry, depth+1); | |
840 | debug_atomic_inc(&nr_cyclic_checks); | |
841 | if (!check_noncircular(entry->class, depth+1)) | |
842 | return print_circular_bug_entry(entry, depth+1); | |
843 | } | |
844 | return 1; | |
845 | } | |
846 | ||
fbb9ce95 | 847 | #ifdef CONFIG_TRACE_IRQFLAGS |
fbb9ce95 IM |
848 | /* |
849 | * Forwards and backwards subgraph searching, for the purposes of | |
850 | * proving that two subgraphs can be connected by a new dependency | |
851 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
852 | */ | |
853 | static enum lock_usage_bit find_usage_bit; | |
854 | static struct lock_class *forwards_match, *backwards_match; | |
855 | ||
856 | /* | |
857 | * Find a node in the forwards-direction dependency sub-graph starting | |
858 | * at <source> that matches <find_usage_bit>. | |
859 | * | |
860 | * Return 2 if such a node exists in the subgraph, and put that node | |
861 | * into <forwards_match>. | |
862 | * | |
863 | * Return 1 otherwise and keep <forwards_match> unchanged. | |
864 | * Return 0 on error. | |
865 | */ | |
866 | static noinline int | |
867 | find_usage_forwards(struct lock_class *source, unsigned int depth) | |
868 | { | |
869 | struct lock_list *entry; | |
870 | int ret; | |
871 | ||
872 | if (depth > max_recursion_depth) | |
873 | max_recursion_depth = depth; | |
ca268c69 | 874 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
875 | return print_infinite_recursion_bug(); |
876 | ||
877 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
878 | if (source->usage_mask & (1 << find_usage_bit)) { | |
879 | forwards_match = source; | |
880 | return 2; | |
881 | } | |
882 | ||
883 | /* | |
884 | * Check this lock's dependency list: | |
885 | */ | |
886 | list_for_each_entry(entry, &source->locks_after, entry) { | |
887 | debug_atomic_inc(&nr_find_usage_forwards_recursions); | |
888 | ret = find_usage_forwards(entry->class, depth+1); | |
889 | if (ret == 2 || ret == 0) | |
890 | return ret; | |
891 | } | |
892 | return 1; | |
893 | } | |
894 | ||
895 | /* | |
896 | * Find a node in the backwards-direction dependency sub-graph starting | |
897 | * at <source> that matches <find_usage_bit>. | |
898 | * | |
899 | * Return 2 if such a node exists in the subgraph, and put that node | |
900 | * into <backwards_match>. | |
901 | * | |
902 | * Return 1 otherwise and keep <backwards_match> unchanged. | |
903 | * Return 0 on error. | |
904 | */ | |
905 | static noinline int | |
906 | find_usage_backwards(struct lock_class *source, unsigned int depth) | |
907 | { | |
908 | struct lock_list *entry; | |
909 | int ret; | |
910 | ||
381a2292 JP |
911 | if (!__raw_spin_is_locked(&lockdep_lock)) |
912 | return DEBUG_LOCKS_WARN_ON(1); | |
913 | ||
fbb9ce95 IM |
914 | if (depth > max_recursion_depth) |
915 | max_recursion_depth = depth; | |
ca268c69 | 916 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
917 | return print_infinite_recursion_bug(); |
918 | ||
919 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
920 | if (source->usage_mask & (1 << find_usage_bit)) { | |
921 | backwards_match = source; | |
922 | return 2; | |
923 | } | |
924 | ||
925 | /* | |
926 | * Check this lock's dependency list: | |
927 | */ | |
928 | list_for_each_entry(entry, &source->locks_before, entry) { | |
929 | debug_atomic_inc(&nr_find_usage_backwards_recursions); | |
930 | ret = find_usage_backwards(entry->class, depth+1); | |
931 | if (ret == 2 || ret == 0) | |
932 | return ret; | |
933 | } | |
934 | return 1; | |
935 | } | |
936 | ||
937 | static int | |
938 | print_bad_irq_dependency(struct task_struct *curr, | |
939 | struct held_lock *prev, | |
940 | struct held_lock *next, | |
941 | enum lock_usage_bit bit1, | |
942 | enum lock_usage_bit bit2, | |
943 | const char *irqclass) | |
944 | { | |
74c383f1 | 945 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
946 | return 0; |
947 | ||
948 | printk("\n======================================================\n"); | |
949 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
950 | irqclass, irqclass); | |
99de055a | 951 | print_kernel_version(); |
fbb9ce95 IM |
952 | printk( "------------------------------------------------------\n"); |
953 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
954 | curr->comm, curr->pid, | |
955 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, | |
956 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
957 | curr->hardirqs_enabled, | |
958 | curr->softirqs_enabled); | |
959 | print_lock(next); | |
960 | ||
961 | printk("\nand this task is already holding:\n"); | |
962 | print_lock(prev); | |
963 | printk("which would create a new lock dependency:\n"); | |
964 | print_lock_name(prev->class); | |
965 | printk(" ->"); | |
966 | print_lock_name(next->class); | |
967 | printk("\n"); | |
968 | ||
969 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
970 | irqclass); | |
971 | print_lock_name(backwards_match); | |
972 | printk("\n... which became %s-irq-safe at:\n", irqclass); | |
973 | ||
974 | print_stack_trace(backwards_match->usage_traces + bit1, 1); | |
975 | ||
976 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
977 | print_lock_name(forwards_match); | |
978 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); | |
979 | printk("..."); | |
980 | ||
981 | print_stack_trace(forwards_match->usage_traces + bit2, 1); | |
982 | ||
983 | printk("\nother info that might help us debug this:\n\n"); | |
984 | lockdep_print_held_locks(curr); | |
985 | ||
986 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); | |
987 | print_lock_dependencies(backwards_match, 0); | |
988 | ||
989 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); | |
990 | print_lock_dependencies(forwards_match, 0); | |
991 | ||
992 | printk("\nstack backtrace:\n"); | |
993 | dump_stack(); | |
994 | ||
995 | return 0; | |
996 | } | |
997 | ||
998 | static int | |
999 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1000 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1001 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1002 | { | |
1003 | int ret; | |
1004 | ||
1005 | find_usage_bit = bit_backwards; | |
1006 | /* fills in <backwards_match> */ | |
1007 | ret = find_usage_backwards(prev->class, 0); | |
1008 | if (!ret || ret == 1) | |
1009 | return ret; | |
1010 | ||
1011 | find_usage_bit = bit_forwards; | |
1012 | ret = find_usage_forwards(next->class, 0); | |
1013 | if (!ret || ret == 1) | |
1014 | return ret; | |
1015 | /* ret == 2 */ | |
1016 | return print_bad_irq_dependency(curr, prev, next, | |
1017 | bit_backwards, bit_forwards, irqclass); | |
1018 | } | |
1019 | ||
8e18257d PZ |
1020 | static int |
1021 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1022 | struct held_lock *next) | |
1023 | { | |
1024 | /* | |
1025 | * Prove that the new dependency does not connect a hardirq-safe | |
1026 | * lock with a hardirq-unsafe lock - to achieve this we search | |
1027 | * the backwards-subgraph starting at <prev>, and the | |
1028 | * forwards-subgraph starting at <next>: | |
1029 | */ | |
1030 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, | |
1031 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1032 | return 0; | |
1033 | ||
1034 | /* | |
1035 | * Prove that the new dependency does not connect a hardirq-safe-read | |
1036 | * lock with a hardirq-unsafe lock - to achieve this we search | |
1037 | * the backwards-subgraph starting at <prev>, and the | |
1038 | * forwards-subgraph starting at <next>: | |
1039 | */ | |
1040 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, | |
1041 | LOCK_ENABLED_HARDIRQS, "hard-read")) | |
1042 | return 0; | |
1043 | ||
1044 | /* | |
1045 | * Prove that the new dependency does not connect a softirq-safe | |
1046 | * lock with a softirq-unsafe lock - to achieve this we search | |
1047 | * the backwards-subgraph starting at <prev>, and the | |
1048 | * forwards-subgraph starting at <next>: | |
1049 | */ | |
1050 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, | |
1051 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1052 | return 0; | |
1053 | /* | |
1054 | * Prove that the new dependency does not connect a softirq-safe-read | |
1055 | * lock with a softirq-unsafe lock - to achieve this we search | |
1056 | * the backwards-subgraph starting at <prev>, and the | |
1057 | * forwards-subgraph starting at <next>: | |
1058 | */ | |
1059 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, | |
1060 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1061 | return 0; | |
1062 | ||
1063 | return 1; | |
1064 | } | |
1065 | ||
1066 | static void inc_chains(void) | |
1067 | { | |
1068 | if (current->hardirq_context) | |
1069 | nr_hardirq_chains++; | |
1070 | else { | |
1071 | if (current->softirq_context) | |
1072 | nr_softirq_chains++; | |
1073 | else | |
1074 | nr_process_chains++; | |
1075 | } | |
1076 | } | |
1077 | ||
1078 | #else | |
1079 | ||
1080 | static inline int | |
1081 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1082 | struct held_lock *next) | |
1083 | { | |
1084 | return 1; | |
1085 | } | |
1086 | ||
1087 | static inline void inc_chains(void) | |
1088 | { | |
1089 | nr_process_chains++; | |
1090 | } | |
1091 | ||
fbb9ce95 IM |
1092 | #endif |
1093 | ||
1094 | static int | |
1095 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1096 | struct held_lock *next) | |
1097 | { | |
74c383f1 | 1098 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1099 | return 0; |
1100 | ||
1101 | printk("\n=============================================\n"); | |
1102 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1103 | print_kernel_version(); |
fbb9ce95 IM |
1104 | printk( "---------------------------------------------\n"); |
1105 | printk("%s/%d is trying to acquire lock:\n", | |
1106 | curr->comm, curr->pid); | |
1107 | print_lock(next); | |
1108 | printk("\nbut task is already holding lock:\n"); | |
1109 | print_lock(prev); | |
1110 | ||
1111 | printk("\nother info that might help us debug this:\n"); | |
1112 | lockdep_print_held_locks(curr); | |
1113 | ||
1114 | printk("\nstack backtrace:\n"); | |
1115 | dump_stack(); | |
1116 | ||
1117 | return 0; | |
1118 | } | |
1119 | ||
1120 | /* | |
1121 | * Check whether we are holding such a class already. | |
1122 | * | |
1123 | * (Note that this has to be done separately, because the graph cannot | |
1124 | * detect such classes of deadlocks.) | |
1125 | * | |
1126 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1127 | */ | |
1128 | static int | |
1129 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1130 | struct lockdep_map *next_instance, int read) | |
1131 | { | |
1132 | struct held_lock *prev; | |
1133 | int i; | |
1134 | ||
1135 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1136 | prev = curr->held_locks + i; | |
1137 | if (prev->class != next->class) | |
1138 | continue; | |
1139 | /* | |
1140 | * Allow read-after-read recursion of the same | |
6c9076ec | 1141 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1142 | */ |
6c9076ec | 1143 | if ((read == 2) && prev->read) |
fbb9ce95 IM |
1144 | return 2; |
1145 | return print_deadlock_bug(curr, prev, next); | |
1146 | } | |
1147 | return 1; | |
1148 | } | |
1149 | ||
1150 | /* | |
1151 | * There was a chain-cache miss, and we are about to add a new dependency | |
1152 | * to a previous lock. We recursively validate the following rules: | |
1153 | * | |
1154 | * - would the adding of the <prev> -> <next> dependency create a | |
1155 | * circular dependency in the graph? [== circular deadlock] | |
1156 | * | |
1157 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1158 | * (in the full backwards-subgraph starting at <prev>) with any | |
1159 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1160 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1161 | * | |
1162 | * - does the new prev->next dependency connect any softirq-safe lock | |
1163 | * (in the full backwards-subgraph starting at <prev>) with any | |
1164 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1165 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1166 | * | |
1167 | * any of these scenarios could lead to a deadlock. | |
1168 | * | |
1169 | * Then if all the validations pass, we add the forwards and backwards | |
1170 | * dependency. | |
1171 | */ | |
1172 | static int | |
1173 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1174 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1175 | { |
1176 | struct lock_list *entry; | |
1177 | int ret; | |
1178 | ||
1179 | /* | |
1180 | * Prove that the new <prev> -> <next> dependency would not | |
1181 | * create a circular dependency in the graph. (We do this by | |
1182 | * forward-recursing into the graph starting at <next>, and | |
1183 | * checking whether we can reach <prev>.) | |
1184 | * | |
1185 | * We are using global variables to control the recursion, to | |
1186 | * keep the stackframe size of the recursive functions low: | |
1187 | */ | |
1188 | check_source = next; | |
1189 | check_target = prev; | |
1190 | if (!(check_noncircular(next->class, 0))) | |
1191 | return print_circular_bug_tail(); | |
1192 | ||
8e18257d | 1193 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1194 | return 0; |
1195 | ||
fbb9ce95 IM |
1196 | /* |
1197 | * For recursive read-locks we do all the dependency checks, | |
1198 | * but we dont store read-triggered dependencies (only | |
1199 | * write-triggered dependencies). This ensures that only the | |
1200 | * write-side dependencies matter, and that if for example a | |
1201 | * write-lock never takes any other locks, then the reads are | |
1202 | * equivalent to a NOP. | |
1203 | */ | |
1204 | if (next->read == 2 || prev->read == 2) | |
1205 | return 1; | |
1206 | /* | |
1207 | * Is the <prev> -> <next> dependency already present? | |
1208 | * | |
1209 | * (this may occur even though this is a new chain: consider | |
1210 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1211 | * chains - the second one will be new, but L1 already has | |
1212 | * L2 added to its dependency list, due to the first chain.) | |
1213 | */ | |
1214 | list_for_each_entry(entry, &prev->class->locks_after, entry) { | |
068135e6 JB |
1215 | if (entry->class == next->class) { |
1216 | if (distance == 1) | |
1217 | entry->distance = 1; | |
fbb9ce95 | 1218 | return 2; |
068135e6 | 1219 | } |
fbb9ce95 IM |
1220 | } |
1221 | ||
1222 | /* | |
1223 | * Ok, all validations passed, add the new lock | |
1224 | * to the previous lock's dependency list: | |
1225 | */ | |
1226 | ret = add_lock_to_list(prev->class, next->class, | |
068135e6 JB |
1227 | &prev->class->locks_after, next->acquire_ip, distance); |
1228 | ||
fbb9ce95 IM |
1229 | if (!ret) |
1230 | return 0; | |
910b1b2e | 1231 | |
fbb9ce95 | 1232 | ret = add_lock_to_list(next->class, prev->class, |
068135e6 | 1233 | &next->class->locks_before, next->acquire_ip, distance); |
910b1b2e JP |
1234 | if (!ret) |
1235 | return 0; | |
fbb9ce95 IM |
1236 | |
1237 | /* | |
8e18257d PZ |
1238 | * Debugging printouts: |
1239 | */ | |
1240 | if (verbose(prev->class) || verbose(next->class)) { | |
1241 | graph_unlock(); | |
1242 | printk("\n new dependency: "); | |
1243 | print_lock_name(prev->class); | |
1244 | printk(" => "); | |
1245 | print_lock_name(next->class); | |
1246 | printk("\n"); | |
fbb9ce95 | 1247 | dump_stack(); |
8e18257d | 1248 | return graph_lock(); |
fbb9ce95 | 1249 | } |
8e18257d PZ |
1250 | return 1; |
1251 | } | |
fbb9ce95 | 1252 | |
8e18257d PZ |
1253 | /* |
1254 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1255 | * The ones that are relevant are (in increasing distance from curr): | |
1256 | * all consecutive trylock entries and the final non-trylock entry - or | |
1257 | * the end of this context's lock-chain - whichever comes first. | |
1258 | */ | |
1259 | static int | |
1260 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1261 | { | |
1262 | int depth = curr->lockdep_depth; | |
1263 | struct held_lock *hlock; | |
d6d897ce | 1264 | |
fbb9ce95 | 1265 | /* |
8e18257d PZ |
1266 | * Debugging checks. |
1267 | * | |
1268 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1269 | */ |
8e18257d PZ |
1270 | if (!depth) |
1271 | goto out_bug; | |
fbb9ce95 | 1272 | /* |
8e18257d PZ |
1273 | * At least two relevant locks must exist for this |
1274 | * to be a head: | |
fbb9ce95 | 1275 | */ |
8e18257d PZ |
1276 | if (curr->held_locks[depth].irq_context != |
1277 | curr->held_locks[depth-1].irq_context) | |
1278 | goto out_bug; | |
74c383f1 | 1279 | |
8e18257d PZ |
1280 | for (;;) { |
1281 | int distance = curr->lockdep_depth - depth + 1; | |
1282 | hlock = curr->held_locks + depth-1; | |
1283 | /* | |
1284 | * Only non-recursive-read entries get new dependencies | |
1285 | * added: | |
1286 | */ | |
1287 | if (hlock->read != 2) { | |
1288 | if (!check_prev_add(curr, hlock, next, distance)) | |
1289 | return 0; | |
1290 | /* | |
1291 | * Stop after the first non-trylock entry, | |
1292 | * as non-trylock entries have added their | |
1293 | * own direct dependencies already, so this | |
1294 | * lock is connected to them indirectly: | |
1295 | */ | |
1296 | if (!hlock->trylock) | |
1297 | break; | |
74c383f1 | 1298 | } |
8e18257d PZ |
1299 | depth--; |
1300 | /* | |
1301 | * End of lock-stack? | |
1302 | */ | |
1303 | if (!depth) | |
1304 | break; | |
1305 | /* | |
1306 | * Stop the search if we cross into another context: | |
1307 | */ | |
1308 | if (curr->held_locks[depth].irq_context != | |
1309 | curr->held_locks[depth-1].irq_context) | |
1310 | break; | |
fbb9ce95 | 1311 | } |
8e18257d PZ |
1312 | return 1; |
1313 | out_bug: | |
1314 | if (!debug_locks_off_graph_unlock()) | |
1315 | return 0; | |
fbb9ce95 | 1316 | |
8e18257d | 1317 | WARN_ON(1); |
fbb9ce95 | 1318 | |
8e18257d | 1319 | return 0; |
fbb9ce95 IM |
1320 | } |
1321 | ||
8e18257d PZ |
1322 | unsigned long nr_lock_chains; |
1323 | static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; | |
1324 | ||
fbb9ce95 IM |
1325 | /* |
1326 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1327 | * add it and return 1 - in this case the new dependency chain is |
1328 | * validated. If the key is already hashed, return 0. | |
1329 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1330 | */ |
81fc685a | 1331 | static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class) |
fbb9ce95 IM |
1332 | { |
1333 | struct list_head *hash_head = chainhashentry(chain_key); | |
1334 | struct lock_chain *chain; | |
1335 | ||
381a2292 JP |
1336 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1337 | return 0; | |
fbb9ce95 IM |
1338 | /* |
1339 | * We can walk it lock-free, because entries only get added | |
1340 | * to the hash: | |
1341 | */ | |
1342 | list_for_each_entry(chain, hash_head, entry) { | |
1343 | if (chain->chain_key == chain_key) { | |
1344 | cache_hit: | |
1345 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1346 | if (very_verbose(class)) |
755cd900 AM |
1347 | printk("\nhash chain already cached, key: " |
1348 | "%016Lx tail class: [%p] %s\n", | |
1349 | (unsigned long long)chain_key, | |
1350 | class->key, class->name); | |
fbb9ce95 IM |
1351 | return 0; |
1352 | } | |
1353 | } | |
81fc685a | 1354 | if (very_verbose(class)) |
755cd900 AM |
1355 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1356 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1357 | /* |
1358 | * Allocate a new chain entry from the static array, and add | |
1359 | * it to the hash: | |
1360 | */ | |
74c383f1 IM |
1361 | if (!graph_lock()) |
1362 | return 0; | |
fbb9ce95 IM |
1363 | /* |
1364 | * We have to walk the chain again locked - to avoid duplicates: | |
1365 | */ | |
1366 | list_for_each_entry(chain, hash_head, entry) { | |
1367 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1368 | graph_unlock(); |
fbb9ce95 IM |
1369 | goto cache_hit; |
1370 | } | |
1371 | } | |
1372 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1373 | if (!debug_locks_off_graph_unlock()) |
1374 | return 0; | |
1375 | ||
fbb9ce95 IM |
1376 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1377 | printk("turning off the locking correctness validator.\n"); | |
1378 | return 0; | |
1379 | } | |
1380 | chain = lock_chains + nr_lock_chains++; | |
1381 | chain->chain_key = chain_key; | |
1382 | list_add_tail_rcu(&chain->entry, hash_head); | |
1383 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1384 | inc_chains(); |
1385 | ||
1386 | return 1; | |
1387 | } | |
1388 | ||
1389 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
1390 | struct held_lock *hlock, int chain_head) | |
1391 | { | |
1392 | /* | |
1393 | * Trylock needs to maintain the stack of held locks, but it | |
1394 | * does not add new dependencies, because trylock can be done | |
1395 | * in any order. | |
1396 | * | |
1397 | * We look up the chain_key and do the O(N^2) check and update of | |
1398 | * the dependencies only if this is a new dependency chain. | |
1399 | * (If lookup_chain_cache() returns with 1 it acquires | |
1400 | * graph_lock for us) | |
1401 | */ | |
1402 | if (!hlock->trylock && (hlock->check == 2) && | |
1403 | lookup_chain_cache(curr->curr_chain_key, hlock->class)) { | |
1404 | /* | |
1405 | * Check whether last held lock: | |
1406 | * | |
1407 | * - is irq-safe, if this lock is irq-unsafe | |
1408 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1409 | * | |
1410 | * And check whether the new lock's dependency graph | |
1411 | * could lead back to the previous lock. | |
1412 | * | |
1413 | * any of these scenarios could lead to a deadlock. If | |
1414 | * All validations | |
1415 | */ | |
1416 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1417 | ||
1418 | if (!ret) | |
1419 | return 0; | |
1420 | /* | |
1421 | * Mark recursive read, as we jump over it when | |
1422 | * building dependencies (just like we jump over | |
1423 | * trylock entries): | |
1424 | */ | |
1425 | if (ret == 2) | |
1426 | hlock->read = 2; | |
1427 | /* | |
1428 | * Add dependency only if this lock is not the head | |
1429 | * of the chain, and if it's not a secondary read-lock: | |
1430 | */ | |
1431 | if (!chain_head && ret != 2) | |
1432 | if (!check_prevs_add(curr, hlock)) | |
1433 | return 0; | |
1434 | graph_unlock(); | |
1435 | } else | |
1436 | /* after lookup_chain_cache(): */ | |
1437 | if (unlikely(!debug_locks)) | |
1438 | return 0; | |
fbb9ce95 IM |
1439 | |
1440 | return 1; | |
1441 | } | |
8e18257d PZ |
1442 | #else |
1443 | static inline int validate_chain(struct task_struct *curr, | |
1444 | struct lockdep_map *lock, struct held_lock *hlock, | |
1445 | int chain_head) | |
1446 | { | |
1447 | return 1; | |
1448 | } | |
ca58abcb | 1449 | #endif |
fbb9ce95 IM |
1450 | |
1451 | /* | |
1452 | * We are building curr_chain_key incrementally, so double-check | |
1453 | * it from scratch, to make sure that it's done correctly: | |
1454 | */ | |
1455 | static void check_chain_key(struct task_struct *curr) | |
1456 | { | |
1457 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1458 | struct held_lock *hlock, *prev_hlock = NULL; | |
1459 | unsigned int i, id; | |
1460 | u64 chain_key = 0; | |
1461 | ||
1462 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1463 | hlock = curr->held_locks + i; | |
1464 | if (chain_key != hlock->prev_chain_key) { | |
1465 | debug_locks_off(); | |
1466 | printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n", | |
1467 | curr->lockdep_depth, i, | |
1468 | (unsigned long long)chain_key, | |
1469 | (unsigned long long)hlock->prev_chain_key); | |
1470 | WARN_ON(1); | |
1471 | return; | |
1472 | } | |
1473 | id = hlock->class - lock_classes; | |
381a2292 JP |
1474 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1475 | return; | |
1476 | ||
fbb9ce95 IM |
1477 | if (prev_hlock && (prev_hlock->irq_context != |
1478 | hlock->irq_context)) | |
1479 | chain_key = 0; | |
1480 | chain_key = iterate_chain_key(chain_key, id); | |
1481 | prev_hlock = hlock; | |
1482 | } | |
1483 | if (chain_key != curr->curr_chain_key) { | |
1484 | debug_locks_off(); | |
1485 | printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n", | |
1486 | curr->lockdep_depth, i, | |
1487 | (unsigned long long)chain_key, | |
1488 | (unsigned long long)curr->curr_chain_key); | |
1489 | WARN_ON(1); | |
1490 | } | |
1491 | #endif | |
1492 | } | |
1493 | ||
8e18257d PZ |
1494 | static int |
1495 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1496 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1497 | { | |
1498 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1499 | return 0; | |
1500 | ||
1501 | printk("\n=================================\n"); | |
1502 | printk( "[ INFO: inconsistent lock state ]\n"); | |
1503 | print_kernel_version(); | |
1504 | printk( "---------------------------------\n"); | |
1505 | ||
1506 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1507 | usage_str[prev_bit], usage_str[new_bit]); | |
1508 | ||
1509 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
1510 | curr->comm, curr->pid, | |
1511 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, | |
1512 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1513 | trace_hardirqs_enabled(curr), | |
1514 | trace_softirqs_enabled(curr)); | |
1515 | print_lock(this); | |
1516 | ||
1517 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
1518 | print_stack_trace(this->class->usage_traces + prev_bit, 1); | |
1519 | ||
1520 | print_irqtrace_events(curr); | |
1521 | printk("\nother info that might help us debug this:\n"); | |
1522 | lockdep_print_held_locks(curr); | |
1523 | ||
1524 | printk("\nstack backtrace:\n"); | |
1525 | dump_stack(); | |
1526 | ||
1527 | return 0; | |
1528 | } | |
1529 | ||
1530 | /* | |
1531 | * Print out an error if an invalid bit is set: | |
1532 | */ | |
1533 | static inline int | |
1534 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1535 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1536 | { | |
1537 | if (unlikely(this->class->usage_mask & (1 << bad_bit))) | |
1538 | return print_usage_bug(curr, this, bad_bit, new_bit); | |
1539 | return 1; | |
1540 | } | |
1541 | ||
1542 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
1543 | enum lock_usage_bit new_bit); | |
1544 | ||
fbb9ce95 IM |
1545 | #ifdef CONFIG_TRACE_IRQFLAGS |
1546 | ||
1547 | /* | |
1548 | * print irq inversion bug: | |
1549 | */ | |
1550 | static int | |
1551 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, | |
1552 | struct held_lock *this, int forwards, | |
1553 | const char *irqclass) | |
1554 | { | |
74c383f1 | 1555 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1556 | return 0; |
1557 | ||
1558 | printk("\n=========================================================\n"); | |
1559 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 1560 | print_kernel_version(); |
fbb9ce95 IM |
1561 | printk( "---------------------------------------------------------\n"); |
1562 | printk("%s/%d just changed the state of lock:\n", | |
1563 | curr->comm, curr->pid); | |
1564 | print_lock(this); | |
1565 | if (forwards) | |
1566 | printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass); | |
1567 | else | |
1568 | printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass); | |
1569 | print_lock_name(other); | |
1570 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); | |
1571 | ||
1572 | printk("\nother info that might help us debug this:\n"); | |
1573 | lockdep_print_held_locks(curr); | |
1574 | ||
1575 | printk("\nthe first lock's dependencies:\n"); | |
1576 | print_lock_dependencies(this->class, 0); | |
1577 | ||
1578 | printk("\nthe second lock's dependencies:\n"); | |
1579 | print_lock_dependencies(other, 0); | |
1580 | ||
1581 | printk("\nstack backtrace:\n"); | |
1582 | dump_stack(); | |
1583 | ||
1584 | return 0; | |
1585 | } | |
1586 | ||
1587 | /* | |
1588 | * Prove that in the forwards-direction subgraph starting at <this> | |
1589 | * there is no lock matching <mask>: | |
1590 | */ | |
1591 | static int | |
1592 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
1593 | enum lock_usage_bit bit, const char *irqclass) | |
1594 | { | |
1595 | int ret; | |
1596 | ||
1597 | find_usage_bit = bit; | |
1598 | /* fills in <forwards_match> */ | |
1599 | ret = find_usage_forwards(this->class, 0); | |
1600 | if (!ret || ret == 1) | |
1601 | return ret; | |
1602 | ||
1603 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); | |
1604 | } | |
1605 | ||
1606 | /* | |
1607 | * Prove that in the backwards-direction subgraph starting at <this> | |
1608 | * there is no lock matching <mask>: | |
1609 | */ | |
1610 | static int | |
1611 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
1612 | enum lock_usage_bit bit, const char *irqclass) | |
1613 | { | |
1614 | int ret; | |
1615 | ||
1616 | find_usage_bit = bit; | |
1617 | /* fills in <backwards_match> */ | |
1618 | ret = find_usage_backwards(this->class, 0); | |
1619 | if (!ret || ret == 1) | |
1620 | return ret; | |
1621 | ||
1622 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); | |
1623 | } | |
1624 | ||
3117df04 | 1625 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
1626 | { |
1627 | printk("irq event stamp: %u\n", curr->irq_events); | |
1628 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
1629 | print_ip_sym(curr->hardirq_enable_ip); | |
1630 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
1631 | print_ip_sym(curr->hardirq_disable_ip); | |
1632 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
1633 | print_ip_sym(curr->softirq_enable_ip); | |
1634 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
1635 | print_ip_sym(curr->softirq_disable_ip); | |
1636 | } | |
1637 | ||
8e18257d | 1638 | static int hardirq_verbose(struct lock_class *class) |
fbb9ce95 | 1639 | { |
8e18257d PZ |
1640 | #if HARDIRQ_VERBOSE |
1641 | return class_filter(class); | |
1642 | #endif | |
fbb9ce95 IM |
1643 | return 0; |
1644 | } | |
1645 | ||
8e18257d | 1646 | static int softirq_verbose(struct lock_class *class) |
fbb9ce95 | 1647 | { |
8e18257d PZ |
1648 | #if SOFTIRQ_VERBOSE |
1649 | return class_filter(class); | |
1650 | #endif | |
1651 | return 0; | |
fbb9ce95 IM |
1652 | } |
1653 | ||
1654 | #define STRICT_READ_CHECKS 1 | |
1655 | ||
8e18257d PZ |
1656 | static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
1657 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 1658 | { |
8e18257d | 1659 | int ret = 1; |
fbb9ce95 | 1660 | |
8e18257d | 1661 | switch(new_bit) { |
fbb9ce95 IM |
1662 | case LOCK_USED_IN_HARDIRQ: |
1663 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1664 | return 0; | |
1665 | if (!valid_state(curr, this, new_bit, | |
1666 | LOCK_ENABLED_HARDIRQS_READ)) | |
1667 | return 0; | |
1668 | /* | |
1669 | * just marked it hardirq-safe, check that this lock | |
1670 | * took no hardirq-unsafe lock in the past: | |
1671 | */ | |
1672 | if (!check_usage_forwards(curr, this, | |
1673 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1674 | return 0; | |
1675 | #if STRICT_READ_CHECKS | |
1676 | /* | |
1677 | * just marked it hardirq-safe, check that this lock | |
1678 | * took no hardirq-unsafe-read lock in the past: | |
1679 | */ | |
1680 | if (!check_usage_forwards(curr, this, | |
1681 | LOCK_ENABLED_HARDIRQS_READ, "hard-read")) | |
1682 | return 0; | |
1683 | #endif | |
1684 | if (hardirq_verbose(this->class)) | |
1685 | ret = 2; | |
1686 | break; | |
1687 | case LOCK_USED_IN_SOFTIRQ: | |
1688 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1689 | return 0; | |
1690 | if (!valid_state(curr, this, new_bit, | |
1691 | LOCK_ENABLED_SOFTIRQS_READ)) | |
1692 | return 0; | |
1693 | /* | |
1694 | * just marked it softirq-safe, check that this lock | |
1695 | * took no softirq-unsafe lock in the past: | |
1696 | */ | |
1697 | if (!check_usage_forwards(curr, this, | |
1698 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1699 | return 0; | |
1700 | #if STRICT_READ_CHECKS | |
1701 | /* | |
1702 | * just marked it softirq-safe, check that this lock | |
1703 | * took no softirq-unsafe-read lock in the past: | |
1704 | */ | |
1705 | if (!check_usage_forwards(curr, this, | |
1706 | LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) | |
1707 | return 0; | |
1708 | #endif | |
1709 | if (softirq_verbose(this->class)) | |
1710 | ret = 2; | |
1711 | break; | |
1712 | case LOCK_USED_IN_HARDIRQ_READ: | |
1713 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1714 | return 0; | |
1715 | /* | |
1716 | * just marked it hardirq-read-safe, check that this lock | |
1717 | * took no hardirq-unsafe lock in the past: | |
1718 | */ | |
1719 | if (!check_usage_forwards(curr, this, | |
1720 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1721 | return 0; | |
1722 | if (hardirq_verbose(this->class)) | |
1723 | ret = 2; | |
1724 | break; | |
1725 | case LOCK_USED_IN_SOFTIRQ_READ: | |
1726 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1727 | return 0; | |
1728 | /* | |
1729 | * just marked it softirq-read-safe, check that this lock | |
1730 | * took no softirq-unsafe lock in the past: | |
1731 | */ | |
1732 | if (!check_usage_forwards(curr, this, | |
1733 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1734 | return 0; | |
1735 | if (softirq_verbose(this->class)) | |
1736 | ret = 2; | |
1737 | break; | |
1738 | case LOCK_ENABLED_HARDIRQS: | |
1739 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
1740 | return 0; | |
1741 | if (!valid_state(curr, this, new_bit, | |
1742 | LOCK_USED_IN_HARDIRQ_READ)) | |
1743 | return 0; | |
1744 | /* | |
1745 | * just marked it hardirq-unsafe, check that no hardirq-safe | |
1746 | * lock in the system ever took it in the past: | |
1747 | */ | |
1748 | if (!check_usage_backwards(curr, this, | |
1749 | LOCK_USED_IN_HARDIRQ, "hard")) | |
1750 | return 0; | |
1751 | #if STRICT_READ_CHECKS | |
1752 | /* | |
1753 | * just marked it hardirq-unsafe, check that no | |
1754 | * hardirq-safe-read lock in the system ever took | |
1755 | * it in the past: | |
1756 | */ | |
1757 | if (!check_usage_backwards(curr, this, | |
1758 | LOCK_USED_IN_HARDIRQ_READ, "hard-read")) | |
1759 | return 0; | |
1760 | #endif | |
1761 | if (hardirq_verbose(this->class)) | |
1762 | ret = 2; | |
1763 | break; | |
1764 | case LOCK_ENABLED_SOFTIRQS: | |
1765 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
1766 | return 0; | |
1767 | if (!valid_state(curr, this, new_bit, | |
1768 | LOCK_USED_IN_SOFTIRQ_READ)) | |
1769 | return 0; | |
1770 | /* | |
1771 | * just marked it softirq-unsafe, check that no softirq-safe | |
1772 | * lock in the system ever took it in the past: | |
1773 | */ | |
1774 | if (!check_usage_backwards(curr, this, | |
1775 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
1776 | return 0; | |
1777 | #if STRICT_READ_CHECKS | |
1778 | /* | |
1779 | * just marked it softirq-unsafe, check that no | |
1780 | * softirq-safe-read lock in the system ever took | |
1781 | * it in the past: | |
1782 | */ | |
1783 | if (!check_usage_backwards(curr, this, | |
1784 | LOCK_USED_IN_SOFTIRQ_READ, "soft-read")) | |
1785 | return 0; | |
1786 | #endif | |
1787 | if (softirq_verbose(this->class)) | |
1788 | ret = 2; | |
1789 | break; | |
1790 | case LOCK_ENABLED_HARDIRQS_READ: | |
1791 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
1792 | return 0; | |
1793 | #if STRICT_READ_CHECKS | |
1794 | /* | |
1795 | * just marked it hardirq-read-unsafe, check that no | |
1796 | * hardirq-safe lock in the system ever took it in the past: | |
1797 | */ | |
1798 | if (!check_usage_backwards(curr, this, | |
1799 | LOCK_USED_IN_HARDIRQ, "hard")) | |
1800 | return 0; | |
1801 | #endif | |
1802 | if (hardirq_verbose(this->class)) | |
1803 | ret = 2; | |
1804 | break; | |
1805 | case LOCK_ENABLED_SOFTIRQS_READ: | |
1806 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
1807 | return 0; | |
1808 | #if STRICT_READ_CHECKS | |
1809 | /* | |
1810 | * just marked it softirq-read-unsafe, check that no | |
1811 | * softirq-safe lock in the system ever took it in the past: | |
1812 | */ | |
1813 | if (!check_usage_backwards(curr, this, | |
1814 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
1815 | return 0; | |
1816 | #endif | |
1817 | if (softirq_verbose(this->class)) | |
1818 | ret = 2; | |
1819 | break; | |
fbb9ce95 | 1820 | default: |
fbb9ce95 | 1821 | WARN_ON(1); |
8e18257d | 1822 | break; |
fbb9ce95 IM |
1823 | } |
1824 | ||
1825 | return ret; | |
1826 | } | |
1827 | ||
fbb9ce95 IM |
1828 | /* |
1829 | * Mark all held locks with a usage bit: | |
1830 | */ | |
1831 | static int | |
4ff773bb | 1832 | mark_held_locks(struct task_struct *curr, int hardirq) |
fbb9ce95 IM |
1833 | { |
1834 | enum lock_usage_bit usage_bit; | |
1835 | struct held_lock *hlock; | |
1836 | int i; | |
1837 | ||
1838 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1839 | hlock = curr->held_locks + i; | |
1840 | ||
1841 | if (hardirq) { | |
1842 | if (hlock->read) | |
1843 | usage_bit = LOCK_ENABLED_HARDIRQS_READ; | |
1844 | else | |
1845 | usage_bit = LOCK_ENABLED_HARDIRQS; | |
1846 | } else { | |
1847 | if (hlock->read) | |
1848 | usage_bit = LOCK_ENABLED_SOFTIRQS_READ; | |
1849 | else | |
1850 | usage_bit = LOCK_ENABLED_SOFTIRQS; | |
1851 | } | |
4ff773bb | 1852 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
1853 | return 0; |
1854 | } | |
1855 | ||
1856 | return 1; | |
1857 | } | |
1858 | ||
1859 | /* | |
1860 | * Debugging helper: via this flag we know that we are in | |
1861 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
1862 | */ | |
1863 | static int early_boot_irqs_enabled; | |
1864 | ||
1865 | void early_boot_irqs_off(void) | |
1866 | { | |
1867 | early_boot_irqs_enabled = 0; | |
1868 | } | |
1869 | ||
1870 | void early_boot_irqs_on(void) | |
1871 | { | |
1872 | early_boot_irqs_enabled = 1; | |
1873 | } | |
1874 | ||
1875 | /* | |
1876 | * Hardirqs will be enabled: | |
1877 | */ | |
1878 | void trace_hardirqs_on(void) | |
1879 | { | |
1880 | struct task_struct *curr = current; | |
1881 | unsigned long ip; | |
1882 | ||
1883 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
1884 | return; | |
1885 | ||
1886 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
1887 | return; | |
1888 | ||
1889 | if (unlikely(curr->hardirqs_enabled)) { | |
1890 | debug_atomic_inc(&redundant_hardirqs_on); | |
1891 | return; | |
1892 | } | |
1893 | /* we'll do an OFF -> ON transition: */ | |
1894 | curr->hardirqs_enabled = 1; | |
1895 | ip = (unsigned long) __builtin_return_address(0); | |
1896 | ||
1897 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1898 | return; | |
1899 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
1900 | return; | |
1901 | /* | |
1902 | * We are going to turn hardirqs on, so set the | |
1903 | * usage bit for all held locks: | |
1904 | */ | |
4ff773bb | 1905 | if (!mark_held_locks(curr, 1)) |
fbb9ce95 IM |
1906 | return; |
1907 | /* | |
1908 | * If we have softirqs enabled, then set the usage | |
1909 | * bit for all held locks. (disabled hardirqs prevented | |
1910 | * this bit from being set before) | |
1911 | */ | |
1912 | if (curr->softirqs_enabled) | |
4ff773bb | 1913 | if (!mark_held_locks(curr, 0)) |
fbb9ce95 IM |
1914 | return; |
1915 | ||
8e18257d PZ |
1916 | curr->hardirq_enable_ip = ip; |
1917 | curr->hardirq_enable_event = ++curr->irq_events; | |
1918 | debug_atomic_inc(&hardirqs_on_events); | |
1919 | } | |
1920 | ||
1921 | EXPORT_SYMBOL(trace_hardirqs_on); | |
1922 | ||
1923 | /* | |
1924 | * Hardirqs were disabled: | |
1925 | */ | |
1926 | void trace_hardirqs_off(void) | |
1927 | { | |
1928 | struct task_struct *curr = current; | |
1929 | ||
1930 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
1931 | return; | |
1932 | ||
1933 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1934 | return; | |
1935 | ||
1936 | if (curr->hardirqs_enabled) { | |
1937 | /* | |
1938 | * We have done an ON -> OFF transition: | |
1939 | */ | |
1940 | curr->hardirqs_enabled = 0; | |
1941 | curr->hardirq_disable_ip = _RET_IP_; | |
1942 | curr->hardirq_disable_event = ++curr->irq_events; | |
1943 | debug_atomic_inc(&hardirqs_off_events); | |
1944 | } else | |
1945 | debug_atomic_inc(&redundant_hardirqs_off); | |
1946 | } | |
1947 | ||
1948 | EXPORT_SYMBOL(trace_hardirqs_off); | |
1949 | ||
1950 | /* | |
1951 | * Softirqs will be enabled: | |
1952 | */ | |
1953 | void trace_softirqs_on(unsigned long ip) | |
1954 | { | |
1955 | struct task_struct *curr = current; | |
1956 | ||
1957 | if (unlikely(!debug_locks)) | |
1958 | return; | |
1959 | ||
1960 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1961 | return; | |
1962 | ||
1963 | if (curr->softirqs_enabled) { | |
1964 | debug_atomic_inc(&redundant_softirqs_on); | |
1965 | return; | |
1966 | } | |
1967 | ||
1968 | /* | |
1969 | * We'll do an OFF -> ON transition: | |
1970 | */ | |
1971 | curr->softirqs_enabled = 1; | |
1972 | curr->softirq_enable_ip = ip; | |
1973 | curr->softirq_enable_event = ++curr->irq_events; | |
1974 | debug_atomic_inc(&softirqs_on_events); | |
1975 | /* | |
1976 | * We are going to turn softirqs on, so set the | |
1977 | * usage bit for all held locks, if hardirqs are | |
1978 | * enabled too: | |
1979 | */ | |
1980 | if (curr->hardirqs_enabled) | |
1981 | mark_held_locks(curr, 0); | |
1982 | } | |
1983 | ||
1984 | /* | |
1985 | * Softirqs were disabled: | |
1986 | */ | |
1987 | void trace_softirqs_off(unsigned long ip) | |
1988 | { | |
1989 | struct task_struct *curr = current; | |
1990 | ||
1991 | if (unlikely(!debug_locks)) | |
1992 | return; | |
1993 | ||
1994 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1995 | return; | |
1996 | ||
1997 | if (curr->softirqs_enabled) { | |
1998 | /* | |
1999 | * We have done an ON -> OFF transition: | |
2000 | */ | |
2001 | curr->softirqs_enabled = 0; | |
2002 | curr->softirq_disable_ip = ip; | |
2003 | curr->softirq_disable_event = ++curr->irq_events; | |
2004 | debug_atomic_inc(&softirqs_off_events); | |
2005 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2006 | } else | |
2007 | debug_atomic_inc(&redundant_softirqs_off); | |
2008 | } | |
2009 | ||
2010 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) | |
2011 | { | |
2012 | /* | |
2013 | * If non-trylock use in a hardirq or softirq context, then | |
2014 | * mark the lock as used in these contexts: | |
2015 | */ | |
2016 | if (!hlock->trylock) { | |
2017 | if (hlock->read) { | |
2018 | if (curr->hardirq_context) | |
2019 | if (!mark_lock(curr, hlock, | |
2020 | LOCK_USED_IN_HARDIRQ_READ)) | |
2021 | return 0; | |
2022 | if (curr->softirq_context) | |
2023 | if (!mark_lock(curr, hlock, | |
2024 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2025 | return 0; | |
2026 | } else { | |
2027 | if (curr->hardirq_context) | |
2028 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2029 | return 0; | |
2030 | if (curr->softirq_context) | |
2031 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2032 | return 0; | |
2033 | } | |
2034 | } | |
2035 | if (!hlock->hardirqs_off) { | |
2036 | if (hlock->read) { | |
2037 | if (!mark_lock(curr, hlock, | |
2038 | LOCK_ENABLED_HARDIRQS_READ)) | |
2039 | return 0; | |
2040 | if (curr->softirqs_enabled) | |
2041 | if (!mark_lock(curr, hlock, | |
2042 | LOCK_ENABLED_SOFTIRQS_READ)) | |
2043 | return 0; | |
2044 | } else { | |
2045 | if (!mark_lock(curr, hlock, | |
2046 | LOCK_ENABLED_HARDIRQS)) | |
2047 | return 0; | |
2048 | if (curr->softirqs_enabled) | |
2049 | if (!mark_lock(curr, hlock, | |
2050 | LOCK_ENABLED_SOFTIRQS)) | |
2051 | return 0; | |
2052 | } | |
2053 | } | |
2054 | ||
2055 | return 1; | |
2056 | } | |
2057 | ||
2058 | static int separate_irq_context(struct task_struct *curr, | |
2059 | struct held_lock *hlock) | |
2060 | { | |
2061 | unsigned int depth = curr->lockdep_depth; | |
2062 | ||
2063 | /* | |
2064 | * Keep track of points where we cross into an interrupt context: | |
2065 | */ | |
2066 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2067 | curr->softirq_context; | |
2068 | if (depth) { | |
2069 | struct held_lock *prev_hlock; | |
2070 | ||
2071 | prev_hlock = curr->held_locks + depth-1; | |
2072 | /* | |
2073 | * If we cross into another context, reset the | |
2074 | * hash key (this also prevents the checking and the | |
2075 | * adding of the dependency to 'prev'): | |
2076 | */ | |
2077 | if (prev_hlock->irq_context != hlock->irq_context) | |
2078 | return 1; | |
2079 | } | |
2080 | return 0; | |
fbb9ce95 IM |
2081 | } |
2082 | ||
8e18257d | 2083 | #else |
fbb9ce95 | 2084 | |
8e18257d PZ |
2085 | static inline |
2086 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2087 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2088 | { |
8e18257d PZ |
2089 | WARN_ON(1); |
2090 | return 1; | |
2091 | } | |
fbb9ce95 | 2092 | |
8e18257d PZ |
2093 | static inline int mark_irqflags(struct task_struct *curr, |
2094 | struct held_lock *hlock) | |
2095 | { | |
2096 | return 1; | |
2097 | } | |
fbb9ce95 | 2098 | |
8e18257d PZ |
2099 | static inline int separate_irq_context(struct task_struct *curr, |
2100 | struct held_lock *hlock) | |
2101 | { | |
2102 | return 0; | |
fbb9ce95 IM |
2103 | } |
2104 | ||
8e18257d | 2105 | #endif |
fbb9ce95 IM |
2106 | |
2107 | /* | |
8e18257d | 2108 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2109 | */ |
8e18257d PZ |
2110 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
2111 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2112 | { |
8e18257d | 2113 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2114 | |
2115 | /* | |
8e18257d PZ |
2116 | * If already set then do not dirty the cacheline, |
2117 | * nor do any checks: | |
fbb9ce95 | 2118 | */ |
8e18257d PZ |
2119 | if (likely(this->class->usage_mask & new_mask)) |
2120 | return 1; | |
2121 | ||
2122 | if (!graph_lock()) | |
2123 | return 0; | |
fbb9ce95 | 2124 | /* |
8e18257d | 2125 | * Make sure we didnt race: |
fbb9ce95 | 2126 | */ |
8e18257d PZ |
2127 | if (unlikely(this->class->usage_mask & new_mask)) { |
2128 | graph_unlock(); | |
2129 | return 1; | |
2130 | } | |
fbb9ce95 | 2131 | |
8e18257d | 2132 | this->class->usage_mask |= new_mask; |
fbb9ce95 | 2133 | |
8e18257d PZ |
2134 | if (!save_trace(this->class->usage_traces + new_bit)) |
2135 | return 0; | |
fbb9ce95 | 2136 | |
8e18257d PZ |
2137 | switch (new_bit) { |
2138 | case LOCK_USED_IN_HARDIRQ: | |
2139 | case LOCK_USED_IN_SOFTIRQ: | |
2140 | case LOCK_USED_IN_HARDIRQ_READ: | |
2141 | case LOCK_USED_IN_SOFTIRQ_READ: | |
2142 | case LOCK_ENABLED_HARDIRQS: | |
2143 | case LOCK_ENABLED_SOFTIRQS: | |
2144 | case LOCK_ENABLED_HARDIRQS_READ: | |
2145 | case LOCK_ENABLED_SOFTIRQS_READ: | |
2146 | ret = mark_lock_irq(curr, this, new_bit); | |
2147 | if (!ret) | |
2148 | return 0; | |
2149 | break; | |
2150 | case LOCK_USED: | |
fbb9ce95 | 2151 | /* |
8e18257d | 2152 | * Add it to the global list of classes: |
fbb9ce95 | 2153 | */ |
8e18257d PZ |
2154 | list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes); |
2155 | debug_atomic_dec(&nr_unused_locks); | |
2156 | break; | |
2157 | default: | |
2158 | if (!debug_locks_off_graph_unlock()) | |
2159 | return 0; | |
2160 | WARN_ON(1); | |
2161 | return 0; | |
2162 | } | |
fbb9ce95 | 2163 | |
8e18257d PZ |
2164 | graph_unlock(); |
2165 | ||
2166 | /* | |
2167 | * We must printk outside of the graph_lock: | |
2168 | */ | |
2169 | if (ret == 2) { | |
2170 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2171 | print_lock(this); | |
2172 | print_irqtrace_events(curr); | |
2173 | dump_stack(); | |
2174 | } | |
2175 | ||
2176 | return ret; | |
2177 | } | |
fbb9ce95 IM |
2178 | |
2179 | /* | |
2180 | * Initialize a lock instance's lock-class mapping info: | |
2181 | */ | |
2182 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2183 | struct lock_class_key *key, int subclass) |
fbb9ce95 IM |
2184 | { |
2185 | if (unlikely(!debug_locks)) | |
2186 | return; | |
2187 | ||
2188 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2189 | return; | |
2190 | if (DEBUG_LOCKS_WARN_ON(!name)) | |
2191 | return; | |
2192 | /* | |
2193 | * Sanity check, the lock-class key must be persistent: | |
2194 | */ | |
2195 | if (!static_obj(key)) { | |
2196 | printk("BUG: key %p not in .data!\n", key); | |
2197 | DEBUG_LOCKS_WARN_ON(1); | |
2198 | return; | |
2199 | } | |
2200 | lock->name = name; | |
2201 | lock->key = key; | |
d6d897ce | 2202 | lock->class_cache = NULL; |
4dfbb9d8 PZ |
2203 | if (subclass) |
2204 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 IM |
2205 | } |
2206 | ||
2207 | EXPORT_SYMBOL_GPL(lockdep_init_map); | |
2208 | ||
2209 | /* | |
2210 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2211 | * We maintain the dependency maps and validate the locking attempt: | |
2212 | */ | |
2213 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2214 | int trylock, int read, int check, int hardirqs_off, | |
2215 | unsigned long ip) | |
2216 | { | |
2217 | struct task_struct *curr = current; | |
d6d897ce | 2218 | struct lock_class *class = NULL; |
fbb9ce95 | 2219 | struct held_lock *hlock; |
fbb9ce95 IM |
2220 | unsigned int depth, id; |
2221 | int chain_head = 0; | |
2222 | u64 chain_key; | |
2223 | ||
2224 | if (unlikely(!debug_locks)) | |
2225 | return 0; | |
2226 | ||
2227 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2228 | return 0; | |
2229 | ||
2230 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2231 | debug_locks_off(); | |
2232 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2233 | printk("turning off the locking correctness validator.\n"); | |
2234 | return 0; | |
2235 | } | |
2236 | ||
d6d897ce IM |
2237 | if (!subclass) |
2238 | class = lock->class_cache; | |
2239 | /* | |
2240 | * Not cached yet or subclass? | |
2241 | */ | |
fbb9ce95 | 2242 | if (unlikely(!class)) { |
4dfbb9d8 | 2243 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2244 | if (!class) |
2245 | return 0; | |
2246 | } | |
2247 | debug_atomic_inc((atomic_t *)&class->ops); | |
2248 | if (very_verbose(class)) { | |
2249 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2250 | if (class->name_version > 1) | |
2251 | printk("#%d", class->name_version); | |
2252 | printk("\n"); | |
2253 | dump_stack(); | |
2254 | } | |
2255 | ||
2256 | /* | |
2257 | * Add the lock to the list of currently held locks. | |
2258 | * (we dont increase the depth just yet, up until the | |
2259 | * dependency checks are done) | |
2260 | */ | |
2261 | depth = curr->lockdep_depth; | |
2262 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2263 | return 0; | |
2264 | ||
2265 | hlock = curr->held_locks + depth; | |
2266 | ||
2267 | hlock->class = class; | |
2268 | hlock->acquire_ip = ip; | |
2269 | hlock->instance = lock; | |
2270 | hlock->trylock = trylock; | |
2271 | hlock->read = read; | |
2272 | hlock->check = check; | |
2273 | hlock->hardirqs_off = hardirqs_off; | |
2274 | ||
8e18257d PZ |
2275 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2276 | return 0; | |
2277 | ||
fbb9ce95 | 2278 | /* mark it as used: */ |
4ff773bb | 2279 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2280 | return 0; |
8e18257d | 2281 | |
fbb9ce95 IM |
2282 | /* |
2283 | * Calculate the chain hash: it's the combined has of all the | |
2284 | * lock keys along the dependency chain. We save the hash value | |
2285 | * at every step so that we can get the current hash easily | |
2286 | * after unlock. The chain hash is then used to cache dependency | |
2287 | * results. | |
2288 | * | |
2289 | * The 'key ID' is what is the most compact key value to drive | |
2290 | * the hash, not class->key. | |
2291 | */ | |
2292 | id = class - lock_classes; | |
2293 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2294 | return 0; | |
2295 | ||
2296 | chain_key = curr->curr_chain_key; | |
2297 | if (!depth) { | |
2298 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2299 | return 0; | |
2300 | chain_head = 1; | |
2301 | } | |
2302 | ||
2303 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2304 | if (separate_irq_context(curr, hlock)) { |
2305 | chain_key = 0; | |
2306 | chain_head = 1; | |
fbb9ce95 | 2307 | } |
fbb9ce95 IM |
2308 | chain_key = iterate_chain_key(chain_key, id); |
2309 | curr->curr_chain_key = chain_key; | |
2310 | ||
8e18257d PZ |
2311 | if (!validate_chain(curr, lock, hlock, chain_head)) |
2312 | return 0; | |
381a2292 | 2313 | |
fbb9ce95 IM |
2314 | curr->lockdep_depth++; |
2315 | check_chain_key(curr); | |
60e114d1 JP |
2316 | #ifdef CONFIG_DEBUG_LOCKDEP |
2317 | if (unlikely(!debug_locks)) | |
2318 | return 0; | |
2319 | #endif | |
fbb9ce95 IM |
2320 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2321 | debug_locks_off(); | |
2322 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2323 | printk("turning off the locking correctness validator.\n"); | |
2324 | return 0; | |
2325 | } | |
381a2292 | 2326 | |
fbb9ce95 IM |
2327 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2328 | max_lockdep_depth = curr->lockdep_depth; | |
2329 | ||
2330 | return 1; | |
2331 | } | |
2332 | ||
2333 | static int | |
2334 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2335 | unsigned long ip) | |
2336 | { | |
2337 | if (!debug_locks_off()) | |
2338 | return 0; | |
2339 | if (debug_locks_silent) | |
2340 | return 0; | |
2341 | ||
2342 | printk("\n=====================================\n"); | |
2343 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2344 | printk( "-------------------------------------\n"); | |
2345 | printk("%s/%d is trying to release lock (", | |
2346 | curr->comm, curr->pid); | |
2347 | print_lockdep_cache(lock); | |
2348 | printk(") at:\n"); | |
2349 | print_ip_sym(ip); | |
2350 | printk("but there are no more locks to release!\n"); | |
2351 | printk("\nother info that might help us debug this:\n"); | |
2352 | lockdep_print_held_locks(curr); | |
2353 | ||
2354 | printk("\nstack backtrace:\n"); | |
2355 | dump_stack(); | |
2356 | ||
2357 | return 0; | |
2358 | } | |
2359 | ||
2360 | /* | |
2361 | * Common debugging checks for both nested and non-nested unlock: | |
2362 | */ | |
2363 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2364 | unsigned long ip) | |
2365 | { | |
2366 | if (unlikely(!debug_locks)) | |
2367 | return 0; | |
2368 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2369 | return 0; | |
2370 | ||
2371 | if (curr->lockdep_depth <= 0) | |
2372 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2373 | ||
2374 | return 1; | |
2375 | } | |
2376 | ||
2377 | /* | |
2378 | * Remove the lock to the list of currently held locks in a | |
2379 | * potentially non-nested (out of order) manner. This is a | |
2380 | * relatively rare operation, as all the unlock APIs default | |
2381 | * to nested mode (which uses lock_release()): | |
2382 | */ | |
2383 | static int | |
2384 | lock_release_non_nested(struct task_struct *curr, | |
2385 | struct lockdep_map *lock, unsigned long ip) | |
2386 | { | |
2387 | struct held_lock *hlock, *prev_hlock; | |
2388 | unsigned int depth; | |
2389 | int i; | |
2390 | ||
2391 | /* | |
2392 | * Check whether the lock exists in the current stack | |
2393 | * of held locks: | |
2394 | */ | |
2395 | depth = curr->lockdep_depth; | |
2396 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2397 | return 0; | |
2398 | ||
2399 | prev_hlock = NULL; | |
2400 | for (i = depth-1; i >= 0; i--) { | |
2401 | hlock = curr->held_locks + i; | |
2402 | /* | |
2403 | * We must not cross into another context: | |
2404 | */ | |
2405 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2406 | break; | |
2407 | if (hlock->instance == lock) | |
2408 | goto found_it; | |
2409 | prev_hlock = hlock; | |
2410 | } | |
2411 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2412 | ||
2413 | found_it: | |
2414 | /* | |
2415 | * We have the right lock to unlock, 'hlock' points to it. | |
2416 | * Now we remove it from the stack, and add back the other | |
2417 | * entries (if any), recalculating the hash along the way: | |
2418 | */ | |
2419 | curr->lockdep_depth = i; | |
2420 | curr->curr_chain_key = hlock->prev_chain_key; | |
2421 | ||
2422 | for (i++; i < depth; i++) { | |
2423 | hlock = curr->held_locks + i; | |
2424 | if (!__lock_acquire(hlock->instance, | |
2425 | hlock->class->subclass, hlock->trylock, | |
2426 | hlock->read, hlock->check, hlock->hardirqs_off, | |
2427 | hlock->acquire_ip)) | |
2428 | return 0; | |
2429 | } | |
2430 | ||
2431 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2432 | return 0; | |
2433 | return 1; | |
2434 | } | |
2435 | ||
2436 | /* | |
2437 | * Remove the lock to the list of currently held locks - this gets | |
2438 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2439 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2440 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2441 | */ | |
2442 | static int lock_release_nested(struct task_struct *curr, | |
2443 | struct lockdep_map *lock, unsigned long ip) | |
2444 | { | |
2445 | struct held_lock *hlock; | |
2446 | unsigned int depth; | |
2447 | ||
2448 | /* | |
2449 | * Pop off the top of the lock stack: | |
2450 | */ | |
2451 | depth = curr->lockdep_depth - 1; | |
2452 | hlock = curr->held_locks + depth; | |
2453 | ||
2454 | /* | |
2455 | * Is the unlock non-nested: | |
2456 | */ | |
2457 | if (hlock->instance != lock) | |
2458 | return lock_release_non_nested(curr, lock, ip); | |
2459 | curr->lockdep_depth--; | |
2460 | ||
2461 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2462 | return 0; | |
2463 | ||
2464 | curr->curr_chain_key = hlock->prev_chain_key; | |
2465 | ||
2466 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2467 | hlock->prev_chain_key = 0; | |
2468 | hlock->class = NULL; | |
2469 | hlock->acquire_ip = 0; | |
2470 | hlock->irq_context = 0; | |
2471 | #endif | |
2472 | return 1; | |
2473 | } | |
2474 | ||
2475 | /* | |
2476 | * Remove the lock to the list of currently held locks - this gets | |
2477 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2478 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2479 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2480 | */ | |
2481 | static void | |
2482 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2483 | { | |
2484 | struct task_struct *curr = current; | |
2485 | ||
2486 | if (!check_unlock(curr, lock, ip)) | |
2487 | return; | |
2488 | ||
2489 | if (nested) { | |
2490 | if (!lock_release_nested(curr, lock, ip)) | |
2491 | return; | |
2492 | } else { | |
2493 | if (!lock_release_non_nested(curr, lock, ip)) | |
2494 | return; | |
2495 | } | |
2496 | ||
2497 | check_chain_key(curr); | |
2498 | } | |
2499 | ||
2500 | /* | |
2501 | * Check whether we follow the irq-flags state precisely: | |
2502 | */ | |
2503 | static void check_flags(unsigned long flags) | |
2504 | { | |
2505 | #if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS) | |
2506 | if (!debug_locks) | |
2507 | return; | |
2508 | ||
2509 | if (irqs_disabled_flags(flags)) | |
2510 | DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled); | |
2511 | else | |
2512 | DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled); | |
2513 | ||
2514 | /* | |
2515 | * We dont accurately track softirq state in e.g. | |
2516 | * hardirq contexts (such as on 4KSTACKS), so only | |
2517 | * check if not in hardirq contexts: | |
2518 | */ | |
2519 | if (!hardirq_count()) { | |
2520 | if (softirq_count()) | |
2521 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
2522 | else | |
2523 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
2524 | } | |
2525 | ||
2526 | if (!debug_locks) | |
2527 | print_irqtrace_events(current); | |
2528 | #endif | |
2529 | } | |
2530 | ||
2531 | /* | |
2532 | * We are not always called with irqs disabled - do that here, | |
2533 | * and also avoid lockdep recursion: | |
2534 | */ | |
2535 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2536 | int trylock, int read, int check, unsigned long ip) | |
2537 | { | |
2538 | unsigned long flags; | |
2539 | ||
2540 | if (unlikely(current->lockdep_recursion)) | |
2541 | return; | |
2542 | ||
2543 | raw_local_irq_save(flags); | |
2544 | check_flags(flags); | |
2545 | ||
2546 | current->lockdep_recursion = 1; | |
2547 | __lock_acquire(lock, subclass, trylock, read, check, | |
2548 | irqs_disabled_flags(flags), ip); | |
2549 | current->lockdep_recursion = 0; | |
2550 | raw_local_irq_restore(flags); | |
2551 | } | |
2552 | ||
2553 | EXPORT_SYMBOL_GPL(lock_acquire); | |
2554 | ||
2555 | void lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2556 | { | |
2557 | unsigned long flags; | |
2558 | ||
2559 | if (unlikely(current->lockdep_recursion)) | |
2560 | return; | |
2561 | ||
2562 | raw_local_irq_save(flags); | |
2563 | check_flags(flags); | |
2564 | current->lockdep_recursion = 1; | |
2565 | __lock_release(lock, nested, ip); | |
2566 | current->lockdep_recursion = 0; | |
2567 | raw_local_irq_restore(flags); | |
2568 | } | |
2569 | ||
2570 | EXPORT_SYMBOL_GPL(lock_release); | |
2571 | ||
2572 | /* | |
2573 | * Used by the testsuite, sanitize the validator state | |
2574 | * after a simulated failure: | |
2575 | */ | |
2576 | ||
2577 | void lockdep_reset(void) | |
2578 | { | |
2579 | unsigned long flags; | |
23d95a03 | 2580 | int i; |
fbb9ce95 IM |
2581 | |
2582 | raw_local_irq_save(flags); | |
2583 | current->curr_chain_key = 0; | |
2584 | current->lockdep_depth = 0; | |
2585 | current->lockdep_recursion = 0; | |
2586 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
2587 | nr_hardirq_chains = 0; | |
2588 | nr_softirq_chains = 0; | |
2589 | nr_process_chains = 0; | |
2590 | debug_locks = 1; | |
23d95a03 IM |
2591 | for (i = 0; i < CHAINHASH_SIZE; i++) |
2592 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
2593 | raw_local_irq_restore(flags); |
2594 | } | |
2595 | ||
2596 | static void zap_class(struct lock_class *class) | |
2597 | { | |
2598 | int i; | |
2599 | ||
2600 | /* | |
2601 | * Remove all dependencies this lock is | |
2602 | * involved in: | |
2603 | */ | |
2604 | for (i = 0; i < nr_list_entries; i++) { | |
2605 | if (list_entries[i].class == class) | |
2606 | list_del_rcu(&list_entries[i].entry); | |
2607 | } | |
2608 | /* | |
2609 | * Unhash the class and remove it from the all_lock_classes list: | |
2610 | */ | |
2611 | list_del_rcu(&class->hash_entry); | |
2612 | list_del_rcu(&class->lock_entry); | |
2613 | ||
2614 | } | |
2615 | ||
2616 | static inline int within(void *addr, void *start, unsigned long size) | |
2617 | { | |
2618 | return addr >= start && addr < start + size; | |
2619 | } | |
2620 | ||
2621 | void lockdep_free_key_range(void *start, unsigned long size) | |
2622 | { | |
2623 | struct lock_class *class, *next; | |
2624 | struct list_head *head; | |
2625 | unsigned long flags; | |
2626 | int i; | |
2627 | ||
2628 | raw_local_irq_save(flags); | |
74c383f1 | 2629 | graph_lock(); |
fbb9ce95 IM |
2630 | |
2631 | /* | |
2632 | * Unhash all classes that were created by this module: | |
2633 | */ | |
2634 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
2635 | head = classhash_table + i; | |
2636 | if (list_empty(head)) | |
2637 | continue; | |
2638 | list_for_each_entry_safe(class, next, head, hash_entry) | |
2639 | if (within(class->key, start, size)) | |
2640 | zap_class(class); | |
2641 | } | |
2642 | ||
74c383f1 | 2643 | graph_unlock(); |
fbb9ce95 IM |
2644 | raw_local_irq_restore(flags); |
2645 | } | |
2646 | ||
2647 | void lockdep_reset_lock(struct lockdep_map *lock) | |
2648 | { | |
d6d897ce | 2649 | struct lock_class *class, *next; |
fbb9ce95 IM |
2650 | struct list_head *head; |
2651 | unsigned long flags; | |
2652 | int i, j; | |
2653 | ||
2654 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
2655 | |
2656 | /* | |
d6d897ce IM |
2657 | * Remove all classes this lock might have: |
2658 | */ | |
2659 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
2660 | /* | |
2661 | * If the class exists we look it up and zap it: | |
2662 | */ | |
2663 | class = look_up_lock_class(lock, j); | |
2664 | if (class) | |
2665 | zap_class(class); | |
2666 | } | |
2667 | /* | |
2668 | * Debug check: in the end all mapped classes should | |
2669 | * be gone. | |
fbb9ce95 | 2670 | */ |
74c383f1 | 2671 | graph_lock(); |
fbb9ce95 IM |
2672 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
2673 | head = classhash_table + i; | |
2674 | if (list_empty(head)) | |
2675 | continue; | |
2676 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 2677 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
2678 | if (debug_locks_off_graph_unlock()) |
2679 | WARN_ON(1); | |
d6d897ce | 2680 | goto out_restore; |
fbb9ce95 IM |
2681 | } |
2682 | } | |
2683 | } | |
74c383f1 | 2684 | graph_unlock(); |
d6d897ce IM |
2685 | |
2686 | out_restore: | |
fbb9ce95 IM |
2687 | raw_local_irq_restore(flags); |
2688 | } | |
2689 | ||
1499993c | 2690 | void lockdep_init(void) |
fbb9ce95 IM |
2691 | { |
2692 | int i; | |
2693 | ||
2694 | /* | |
2695 | * Some architectures have their own start_kernel() | |
2696 | * code which calls lockdep_init(), while we also | |
2697 | * call lockdep_init() from the start_kernel() itself, | |
2698 | * and we want to initialize the hashes only once: | |
2699 | */ | |
2700 | if (lockdep_initialized) | |
2701 | return; | |
2702 | ||
2703 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
2704 | INIT_LIST_HEAD(classhash_table + i); | |
2705 | ||
2706 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
2707 | INIT_LIST_HEAD(chainhash_table + i); | |
2708 | ||
2709 | lockdep_initialized = 1; | |
2710 | } | |
2711 | ||
2712 | void __init lockdep_info(void) | |
2713 | { | |
2714 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
2715 | ||
2716 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); | |
2717 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); | |
2718 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
2719 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); | |
2720 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); | |
2721 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
2722 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
2723 | ||
2724 | printk(" memory used by lock dependency info: %lu kB\n", | |
2725 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
2726 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
2727 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
2728 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
2729 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
2730 | ||
2731 | printk(" per task-struct memory footprint: %lu bytes\n", | |
2732 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
2733 | ||
2734 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2735 | if (lockdep_init_error) | |
2736 | printk("WARNING: lockdep init error! Arch code didnt call lockdep_init() early enough?\n"); | |
2737 | #endif | |
2738 | } | |
2739 | ||
2740 | static inline int in_range(const void *start, const void *addr, const void *end) | |
2741 | { | |
2742 | return addr >= start && addr <= end; | |
2743 | } | |
2744 | ||
2745 | static void | |
2746 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 2747 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
2748 | { |
2749 | if (!debug_locks_off()) | |
2750 | return; | |
2751 | if (debug_locks_silent) | |
2752 | return; | |
2753 | ||
2754 | printk("\n=========================\n"); | |
2755 | printk( "[ BUG: held lock freed! ]\n"); | |
2756 | printk( "-------------------------\n"); | |
2757 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
2758 | curr->comm, curr->pid, mem_from, mem_to-1); | |
55794a41 | 2759 | print_lock(hlock); |
fbb9ce95 IM |
2760 | lockdep_print_held_locks(curr); |
2761 | ||
2762 | printk("\nstack backtrace:\n"); | |
2763 | dump_stack(); | |
2764 | } | |
2765 | ||
2766 | /* | |
2767 | * Called when kernel memory is freed (or unmapped), or if a lock | |
2768 | * is destroyed or reinitialized - this code checks whether there is | |
2769 | * any held lock in the memory range of <from> to <to>: | |
2770 | */ | |
2771 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
2772 | { | |
2773 | const void *mem_to = mem_from + mem_len, *lock_from, *lock_to; | |
2774 | struct task_struct *curr = current; | |
2775 | struct held_lock *hlock; | |
2776 | unsigned long flags; | |
2777 | int i; | |
2778 | ||
2779 | if (unlikely(!debug_locks)) | |
2780 | return; | |
2781 | ||
2782 | local_irq_save(flags); | |
2783 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2784 | hlock = curr->held_locks + i; | |
2785 | ||
2786 | lock_from = (void *)hlock->instance; | |
2787 | lock_to = (void *)(hlock->instance + 1); | |
2788 | ||
2789 | if (!in_range(mem_from, lock_from, mem_to) && | |
2790 | !in_range(mem_from, lock_to, mem_to)) | |
2791 | continue; | |
2792 | ||
55794a41 | 2793 | print_freed_lock_bug(curr, mem_from, mem_to, hlock); |
fbb9ce95 IM |
2794 | break; |
2795 | } | |
2796 | local_irq_restore(flags); | |
2797 | } | |
ed07536e | 2798 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
2799 | |
2800 | static void print_held_locks_bug(struct task_struct *curr) | |
2801 | { | |
2802 | if (!debug_locks_off()) | |
2803 | return; | |
2804 | if (debug_locks_silent) | |
2805 | return; | |
2806 | ||
2807 | printk("\n=====================================\n"); | |
2808 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
2809 | printk( "-------------------------------------\n"); | |
2810 | printk("%s/%d is exiting with locks still held!\n", | |
2811 | curr->comm, curr->pid); | |
2812 | lockdep_print_held_locks(curr); | |
2813 | ||
2814 | printk("\nstack backtrace:\n"); | |
2815 | dump_stack(); | |
2816 | } | |
2817 | ||
2818 | void debug_check_no_locks_held(struct task_struct *task) | |
2819 | { | |
2820 | if (unlikely(task->lockdep_depth > 0)) | |
2821 | print_held_locks_bug(task); | |
2822 | } | |
2823 | ||
2824 | void debug_show_all_locks(void) | |
2825 | { | |
2826 | struct task_struct *g, *p; | |
2827 | int count = 10; | |
2828 | int unlock = 1; | |
2829 | ||
9c35dd7f JP |
2830 | if (unlikely(!debug_locks)) { |
2831 | printk("INFO: lockdep is turned off.\n"); | |
2832 | return; | |
2833 | } | |
fbb9ce95 IM |
2834 | printk("\nShowing all locks held in the system:\n"); |
2835 | ||
2836 | /* | |
2837 | * Here we try to get the tasklist_lock as hard as possible, | |
2838 | * if not successful after 2 seconds we ignore it (but keep | |
2839 | * trying). This is to enable a debug printout even if a | |
2840 | * tasklist_lock-holding task deadlocks or crashes. | |
2841 | */ | |
2842 | retry: | |
2843 | if (!read_trylock(&tasklist_lock)) { | |
2844 | if (count == 10) | |
2845 | printk("hm, tasklist_lock locked, retrying... "); | |
2846 | if (count) { | |
2847 | count--; | |
2848 | printk(" #%d", 10-count); | |
2849 | mdelay(200); | |
2850 | goto retry; | |
2851 | } | |
2852 | printk(" ignoring it.\n"); | |
2853 | unlock = 0; | |
2854 | } | |
2855 | if (count != 10) | |
2856 | printk(" locked it.\n"); | |
2857 | ||
2858 | do_each_thread(g, p) { | |
2859 | if (p->lockdep_depth) | |
2860 | lockdep_print_held_locks(p); | |
2861 | if (!unlock) | |
2862 | if (read_trylock(&tasklist_lock)) | |
2863 | unlock = 1; | |
2864 | } while_each_thread(g, p); | |
2865 | ||
2866 | printk("\n"); | |
2867 | printk("=============================================\n\n"); | |
2868 | ||
2869 | if (unlock) | |
2870 | read_unlock(&tasklist_lock); | |
2871 | } | |
2872 | ||
2873 | EXPORT_SYMBOL_GPL(debug_show_all_locks); | |
2874 | ||
2875 | void debug_show_held_locks(struct task_struct *task) | |
2876 | { | |
9c35dd7f JP |
2877 | if (unlikely(!debug_locks)) { |
2878 | printk("INFO: lockdep is turned off.\n"); | |
2879 | return; | |
2880 | } | |
fbb9ce95 IM |
2881 | lockdep_print_held_locks(task); |
2882 | } | |
2883 | ||
2884 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |