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 | ||
98 | /* | |
74c383f1 | 99 | * Allocate a lockdep entry. (assumes the graph_lock held, returns |
fbb9ce95 IM |
100 | * with NULL on failure) |
101 | */ | |
102 | static struct lock_list *alloc_list_entry(void) | |
103 | { | |
104 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
74c383f1 IM |
105 | if (!debug_locks_off_graph_unlock()) |
106 | return NULL; | |
107 | ||
fbb9ce95 IM |
108 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); |
109 | printk("turning off the locking correctness validator.\n"); | |
110 | return NULL; | |
111 | } | |
112 | return list_entries + nr_list_entries++; | |
113 | } | |
114 | ||
115 | /* | |
116 | * All data structures here are protected by the global debug_lock. | |
117 | * | |
118 | * Mutex key structs only get allocated, once during bootup, and never | |
119 | * get freed - this significantly simplifies the debugging code. | |
120 | */ | |
121 | unsigned long nr_lock_classes; | |
122 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
123 | ||
124 | /* | |
125 | * We keep a global list of all lock classes. The list only grows, | |
126 | * never shrinks. The list is only accessed with the lockdep | |
127 | * spinlock lock held. | |
128 | */ | |
129 | LIST_HEAD(all_lock_classes); | |
130 | ||
131 | /* | |
132 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
133 | */ | |
134 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
135 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
136 | #define CLASSHASH_MASK (CLASSHASH_SIZE - 1) | |
137 | #define __classhashfn(key) ((((unsigned long)key >> CLASSHASH_BITS) + (unsigned long)key) & CLASSHASH_MASK) | |
138 | #define classhashentry(key) (classhash_table + __classhashfn((key))) | |
139 | ||
140 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
141 | ||
142 | unsigned long nr_lock_chains; | |
143 | static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; | |
144 | ||
145 | /* | |
146 | * We put the lock dependency chains into a hash-table as well, to cache | |
147 | * their existence: | |
148 | */ | |
149 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
150 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
151 | #define CHAINHASH_MASK (CHAINHASH_SIZE - 1) | |
152 | #define __chainhashfn(chain) \ | |
153 | (((chain >> CHAINHASH_BITS) + chain) & CHAINHASH_MASK) | |
154 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) | |
155 | ||
156 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
157 | ||
158 | /* | |
159 | * The hash key of the lock dependency chains is a hash itself too: | |
160 | * it's a hash of all locks taken up to that lock, including that lock. | |
161 | * It's a 64-bit hash, because it's important for the keys to be | |
162 | * unique. | |
163 | */ | |
164 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
165 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
166 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
167 | (key2)) |
168 | ||
169 | void lockdep_off(void) | |
170 | { | |
171 | current->lockdep_recursion++; | |
172 | } | |
173 | ||
174 | EXPORT_SYMBOL(lockdep_off); | |
175 | ||
176 | void lockdep_on(void) | |
177 | { | |
178 | current->lockdep_recursion--; | |
179 | } | |
180 | ||
181 | EXPORT_SYMBOL(lockdep_on); | |
182 | ||
fbb9ce95 IM |
183 | /* |
184 | * Debugging switches: | |
185 | */ | |
186 | ||
187 | #define VERBOSE 0 | |
33e94e96 | 188 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
189 | |
190 | #if VERBOSE | |
191 | # define HARDIRQ_VERBOSE 1 | |
192 | # define SOFTIRQ_VERBOSE 1 | |
193 | #else | |
194 | # define HARDIRQ_VERBOSE 0 | |
195 | # define SOFTIRQ_VERBOSE 0 | |
196 | #endif | |
197 | ||
198 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE | |
199 | /* | |
200 | * Quick filtering for interesting events: | |
201 | */ | |
202 | static int class_filter(struct lock_class *class) | |
203 | { | |
f9829cce AK |
204 | #if 0 |
205 | /* Example */ | |
fbb9ce95 | 206 | if (class->name_version == 1 && |
f9829cce | 207 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
208 | return 1; |
209 | if (class->name_version == 1 && | |
f9829cce | 210 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 211 | return 1; |
f9829cce | 212 | #endif |
a6640897 IM |
213 | /* Filter everything else. 1 would be to allow everything else */ |
214 | return 0; | |
fbb9ce95 IM |
215 | } |
216 | #endif | |
217 | ||
218 | static int verbose(struct lock_class *class) | |
219 | { | |
220 | #if VERBOSE | |
221 | return class_filter(class); | |
222 | #endif | |
223 | return 0; | |
224 | } | |
225 | ||
226 | #ifdef CONFIG_TRACE_IRQFLAGS | |
227 | ||
228 | static int hardirq_verbose(struct lock_class *class) | |
229 | { | |
230 | #if HARDIRQ_VERBOSE | |
231 | return class_filter(class); | |
232 | #endif | |
233 | return 0; | |
234 | } | |
235 | ||
236 | static int softirq_verbose(struct lock_class *class) | |
237 | { | |
238 | #if SOFTIRQ_VERBOSE | |
239 | return class_filter(class); | |
240 | #endif | |
241 | return 0; | |
242 | } | |
243 | ||
244 | #endif | |
245 | ||
246 | /* | |
247 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 248 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
249 | */ |
250 | unsigned long nr_stack_trace_entries; | |
251 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
252 | ||
253 | static int save_trace(struct stack_trace *trace) | |
254 | { | |
255 | trace->nr_entries = 0; | |
256 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
257 | trace->entries = stack_trace + nr_stack_trace_entries; | |
258 | ||
5a1b3999 | 259 | trace->skip = 3; |
5a1b3999 | 260 | |
ab1b6f03 | 261 | save_stack_trace(trace); |
fbb9ce95 IM |
262 | |
263 | trace->max_entries = trace->nr_entries; | |
264 | ||
265 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
266 | |
267 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
268 | if (!debug_locks_off_graph_unlock()) |
269 | return 0; | |
270 | ||
271 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
272 | printk("turning off the locking correctness validator.\n"); | |
273 | dump_stack(); | |
274 | ||
fbb9ce95 IM |
275 | return 0; |
276 | } | |
277 | ||
278 | return 1; | |
279 | } | |
280 | ||
281 | unsigned int nr_hardirq_chains; | |
282 | unsigned int nr_softirq_chains; | |
283 | unsigned int nr_process_chains; | |
284 | unsigned int max_lockdep_depth; | |
285 | unsigned int max_recursion_depth; | |
286 | ||
287 | #ifdef CONFIG_DEBUG_LOCKDEP | |
288 | /* | |
289 | * We cannot printk in early bootup code. Not even early_printk() | |
290 | * might work. So we mark any initialization errors and printk | |
291 | * about it later on, in lockdep_info(). | |
292 | */ | |
293 | static int lockdep_init_error; | |
294 | ||
295 | /* | |
296 | * Various lockdep statistics: | |
297 | */ | |
298 | atomic_t chain_lookup_hits; | |
299 | atomic_t chain_lookup_misses; | |
300 | atomic_t hardirqs_on_events; | |
301 | atomic_t hardirqs_off_events; | |
302 | atomic_t redundant_hardirqs_on; | |
303 | atomic_t redundant_hardirqs_off; | |
304 | atomic_t softirqs_on_events; | |
305 | atomic_t softirqs_off_events; | |
306 | atomic_t redundant_softirqs_on; | |
307 | atomic_t redundant_softirqs_off; | |
308 | atomic_t nr_unused_locks; | |
309 | atomic_t nr_cyclic_checks; | |
310 | atomic_t nr_cyclic_check_recursions; | |
311 | atomic_t nr_find_usage_forwards_checks; | |
312 | atomic_t nr_find_usage_forwards_recursions; | |
313 | atomic_t nr_find_usage_backwards_checks; | |
314 | atomic_t nr_find_usage_backwards_recursions; | |
315 | # define debug_atomic_inc(ptr) atomic_inc(ptr) | |
316 | # define debug_atomic_dec(ptr) atomic_dec(ptr) | |
317 | # define debug_atomic_read(ptr) atomic_read(ptr) | |
318 | #else | |
319 | # define debug_atomic_inc(ptr) do { } while (0) | |
320 | # define debug_atomic_dec(ptr) do { } while (0) | |
321 | # define debug_atomic_read(ptr) 0 | |
322 | #endif | |
323 | ||
324 | /* | |
325 | * Locking printouts: | |
326 | */ | |
327 | ||
328 | static const char *usage_str[] = | |
329 | { | |
330 | [LOCK_USED] = "initial-use ", | |
331 | [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W", | |
332 | [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W", | |
333 | [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W", | |
334 | [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W", | |
335 | [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R", | |
336 | [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R", | |
337 | [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R", | |
338 | [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R", | |
339 | }; | |
340 | ||
341 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
342 | { | |
343 | unsigned long offs, size; | |
344 | char *modname; | |
345 | ||
346 | return kallsyms_lookup((unsigned long)key, &size, &offs, &modname, str); | |
347 | } | |
348 | ||
349 | void | |
350 | get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4) | |
351 | { | |
352 | *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.'; | |
353 | ||
354 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) | |
355 | *c1 = '+'; | |
356 | else | |
357 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) | |
358 | *c1 = '-'; | |
359 | ||
360 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) | |
361 | *c2 = '+'; | |
362 | else | |
363 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) | |
364 | *c2 = '-'; | |
365 | ||
366 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
367 | *c3 = '-'; | |
368 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { | |
369 | *c3 = '+'; | |
370 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) | |
371 | *c3 = '?'; | |
372 | } | |
373 | ||
374 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
375 | *c4 = '-'; | |
376 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { | |
377 | *c4 = '+'; | |
378 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) | |
379 | *c4 = '?'; | |
380 | } | |
381 | } | |
382 | ||
383 | static void print_lock_name(struct lock_class *class) | |
384 | { | |
b23984d0 | 385 | char str[KSYM_NAME_LEN + 1], c1, c2, c3, c4; |
fbb9ce95 IM |
386 | const char *name; |
387 | ||
388 | get_usage_chars(class, &c1, &c2, &c3, &c4); | |
389 | ||
390 | name = class->name; | |
391 | if (!name) { | |
392 | name = __get_key_name(class->key, str); | |
393 | printk(" (%s", name); | |
394 | } else { | |
395 | printk(" (%s", name); | |
396 | if (class->name_version > 1) | |
397 | printk("#%d", class->name_version); | |
398 | if (class->subclass) | |
399 | printk("/%d", class->subclass); | |
400 | } | |
401 | printk("){%c%c%c%c}", c1, c2, c3, c4); | |
402 | } | |
403 | ||
404 | static void print_lockdep_cache(struct lockdep_map *lock) | |
405 | { | |
406 | const char *name; | |
b23984d0 | 407 | char str[KSYM_NAME_LEN + 1]; |
fbb9ce95 IM |
408 | |
409 | name = lock->name; | |
410 | if (!name) | |
411 | name = __get_key_name(lock->key->subkeys, str); | |
412 | ||
413 | printk("%s", name); | |
414 | } | |
415 | ||
416 | static void print_lock(struct held_lock *hlock) | |
417 | { | |
418 | print_lock_name(hlock->class); | |
419 | printk(", at: "); | |
420 | print_ip_sym(hlock->acquire_ip); | |
421 | } | |
422 | ||
423 | static void lockdep_print_held_locks(struct task_struct *curr) | |
424 | { | |
425 | int i, depth = curr->lockdep_depth; | |
426 | ||
427 | if (!depth) { | |
428 | printk("no locks held by %s/%d.\n", curr->comm, curr->pid); | |
429 | return; | |
430 | } | |
431 | printk("%d lock%s held by %s/%d:\n", | |
432 | depth, depth > 1 ? "s" : "", curr->comm, curr->pid); | |
433 | ||
434 | for (i = 0; i < depth; i++) { | |
435 | printk(" #%d: ", i); | |
436 | print_lock(curr->held_locks + i); | |
437 | } | |
438 | } | |
fbb9ce95 IM |
439 | |
440 | static void print_lock_class_header(struct lock_class *class, int depth) | |
441 | { | |
442 | int bit; | |
443 | ||
f9829cce | 444 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
445 | print_lock_name(class); |
446 | printk(" ops: %lu", class->ops); | |
447 | printk(" {\n"); | |
448 | ||
449 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
450 | if (class->usage_mask & (1 << bit)) { | |
451 | int len = depth; | |
452 | ||
f9829cce | 453 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
454 | len += printk(" at:\n"); |
455 | print_stack_trace(class->usage_traces + bit, len); | |
456 | } | |
457 | } | |
f9829cce | 458 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 459 | |
f9829cce | 460 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
461 | print_ip_sym((unsigned long)class->key); |
462 | } | |
463 | ||
464 | /* | |
465 | * printk all lock dependencies starting at <entry>: | |
466 | */ | |
467 | static void print_lock_dependencies(struct lock_class *class, int depth) | |
468 | { | |
469 | struct lock_list *entry; | |
470 | ||
471 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) | |
472 | return; | |
473 | ||
474 | print_lock_class_header(class, depth); | |
475 | ||
476 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
477 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
478 | return; | |
479 | ||
fbb9ce95 IM |
480 | print_lock_dependencies(entry->class, depth + 1); |
481 | ||
f9829cce | 482 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
483 | print_stack_trace(&entry->trace, 2); |
484 | printk("\n"); | |
485 | } | |
486 | } | |
487 | ||
488 | /* | |
489 | * Add a new dependency to the head of the list: | |
490 | */ | |
491 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
068135e6 | 492 | struct list_head *head, unsigned long ip, int distance) |
fbb9ce95 IM |
493 | { |
494 | struct lock_list *entry; | |
495 | /* | |
496 | * Lock not present yet - get a new dependency struct and | |
497 | * add it to the list: | |
498 | */ | |
499 | entry = alloc_list_entry(); | |
500 | if (!entry) | |
501 | return 0; | |
502 | ||
503 | entry->class = this; | |
068135e6 | 504 | entry->distance = distance; |
910b1b2e JP |
505 | if (!save_trace(&entry->trace)) |
506 | return 0; | |
fbb9ce95 IM |
507 | |
508 | /* | |
509 | * Since we never remove from the dependency list, the list can | |
510 | * be walked lockless by other CPUs, it's only allocation | |
511 | * that must be protected by the spinlock. But this also means | |
512 | * we must make new entries visible only once writes to the | |
513 | * entry become visible - hence the RCU op: | |
514 | */ | |
515 | list_add_tail_rcu(&entry->entry, head); | |
516 | ||
517 | return 1; | |
518 | } | |
519 | ||
520 | /* | |
521 | * Recursive, forwards-direction lock-dependency checking, used for | |
522 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
523 | * checking. | |
524 | * | |
525 | * (to keep the stackframe of the recursive functions small we | |
526 | * use these global variables, and we also mark various helper | |
527 | * functions as noinline.) | |
528 | */ | |
529 | static struct held_lock *check_source, *check_target; | |
530 | ||
531 | /* | |
532 | * Print a dependency chain entry (this is only done when a deadlock | |
533 | * has been detected): | |
534 | */ | |
535 | static noinline int | |
536 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |
537 | { | |
538 | if (debug_locks_silent) | |
539 | return 0; | |
540 | printk("\n-> #%u", depth); | |
541 | print_lock_name(target->class); | |
542 | printk(":\n"); | |
543 | print_stack_trace(&target->trace, 6); | |
544 | ||
545 | return 0; | |
546 | } | |
547 | ||
99de055a DJ |
548 | static void print_kernel_version(void) |
549 | { | |
96b644bd SH |
550 | printk("%s %.*s\n", init_utsname()->release, |
551 | (int)strcspn(init_utsname()->version, " "), | |
552 | init_utsname()->version); | |
99de055a DJ |
553 | } |
554 | ||
fbb9ce95 IM |
555 | /* |
556 | * When a circular dependency is detected, print the | |
557 | * header first: | |
558 | */ | |
559 | static noinline int | |
560 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) | |
561 | { | |
562 | struct task_struct *curr = current; | |
563 | ||
74c383f1 | 564 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
565 | return 0; |
566 | ||
567 | printk("\n=======================================================\n"); | |
568 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
99de055a | 569 | print_kernel_version(); |
fbb9ce95 IM |
570 | printk( "-------------------------------------------------------\n"); |
571 | printk("%s/%d is trying to acquire lock:\n", | |
572 | curr->comm, curr->pid); | |
573 | print_lock(check_source); | |
574 | printk("\nbut task is already holding lock:\n"); | |
575 | print_lock(check_target); | |
576 | printk("\nwhich lock already depends on the new lock.\n\n"); | |
577 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
578 | ||
579 | print_circular_bug_entry(entry, depth); | |
580 | ||
581 | return 0; | |
582 | } | |
583 | ||
584 | static noinline int print_circular_bug_tail(void) | |
585 | { | |
586 | struct task_struct *curr = current; | |
587 | struct lock_list this; | |
588 | ||
589 | if (debug_locks_silent) | |
590 | return 0; | |
591 | ||
592 | this.class = check_source->class; | |
910b1b2e JP |
593 | if (!save_trace(&this.trace)) |
594 | return 0; | |
74c383f1 | 595 | |
fbb9ce95 IM |
596 | print_circular_bug_entry(&this, 0); |
597 | ||
598 | printk("\nother info that might help us debug this:\n\n"); | |
599 | lockdep_print_held_locks(curr); | |
600 | ||
601 | printk("\nstack backtrace:\n"); | |
602 | dump_stack(); | |
603 | ||
604 | return 0; | |
605 | } | |
606 | ||
ca268c69 IM |
607 | #define RECURSION_LIMIT 40 |
608 | ||
fbb9ce95 IM |
609 | static int noinline print_infinite_recursion_bug(void) |
610 | { | |
74c383f1 IM |
611 | if (!debug_locks_off_graph_unlock()) |
612 | return 0; | |
613 | ||
614 | WARN_ON(1); | |
fbb9ce95 IM |
615 | |
616 | return 0; | |
617 | } | |
618 | ||
619 | /* | |
620 | * Prove that the dependency graph starting at <entry> can not | |
621 | * lead to <target>. Print an error and return 0 if it does. | |
622 | */ | |
623 | static noinline int | |
624 | check_noncircular(struct lock_class *source, unsigned int depth) | |
625 | { | |
626 | struct lock_list *entry; | |
627 | ||
628 | debug_atomic_inc(&nr_cyclic_check_recursions); | |
629 | if (depth > max_recursion_depth) | |
630 | max_recursion_depth = depth; | |
ca268c69 | 631 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
632 | return print_infinite_recursion_bug(); |
633 | /* | |
634 | * Check this lock's dependency list: | |
635 | */ | |
636 | list_for_each_entry(entry, &source->locks_after, entry) { | |
637 | if (entry->class == check_target->class) | |
638 | return print_circular_bug_header(entry, depth+1); | |
639 | debug_atomic_inc(&nr_cyclic_checks); | |
640 | if (!check_noncircular(entry->class, depth+1)) | |
641 | return print_circular_bug_entry(entry, depth+1); | |
642 | } | |
643 | return 1; | |
644 | } | |
645 | ||
646 | static int very_verbose(struct lock_class *class) | |
647 | { | |
648 | #if VERY_VERBOSE | |
649 | return class_filter(class); | |
650 | #endif | |
651 | return 0; | |
652 | } | |
653 | #ifdef CONFIG_TRACE_IRQFLAGS | |
654 | ||
655 | /* | |
656 | * Forwards and backwards subgraph searching, for the purposes of | |
657 | * proving that two subgraphs can be connected by a new dependency | |
658 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
659 | */ | |
660 | static enum lock_usage_bit find_usage_bit; | |
661 | static struct lock_class *forwards_match, *backwards_match; | |
662 | ||
663 | /* | |
664 | * Find a node in the forwards-direction dependency sub-graph starting | |
665 | * at <source> that matches <find_usage_bit>. | |
666 | * | |
667 | * Return 2 if such a node exists in the subgraph, and put that node | |
668 | * into <forwards_match>. | |
669 | * | |
670 | * Return 1 otherwise and keep <forwards_match> unchanged. | |
671 | * Return 0 on error. | |
672 | */ | |
673 | static noinline int | |
674 | find_usage_forwards(struct lock_class *source, unsigned int depth) | |
675 | { | |
676 | struct lock_list *entry; | |
677 | int ret; | |
678 | ||
679 | if (depth > max_recursion_depth) | |
680 | max_recursion_depth = depth; | |
ca268c69 | 681 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
682 | return print_infinite_recursion_bug(); |
683 | ||
684 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
685 | if (source->usage_mask & (1 << find_usage_bit)) { | |
686 | forwards_match = source; | |
687 | return 2; | |
688 | } | |
689 | ||
690 | /* | |
691 | * Check this lock's dependency list: | |
692 | */ | |
693 | list_for_each_entry(entry, &source->locks_after, entry) { | |
694 | debug_atomic_inc(&nr_find_usage_forwards_recursions); | |
695 | ret = find_usage_forwards(entry->class, depth+1); | |
696 | if (ret == 2 || ret == 0) | |
697 | return ret; | |
698 | } | |
699 | return 1; | |
700 | } | |
701 | ||
702 | /* | |
703 | * Find a node in the backwards-direction dependency sub-graph starting | |
704 | * at <source> that matches <find_usage_bit>. | |
705 | * | |
706 | * Return 2 if such a node exists in the subgraph, and put that node | |
707 | * into <backwards_match>. | |
708 | * | |
709 | * Return 1 otherwise and keep <backwards_match> unchanged. | |
710 | * Return 0 on error. | |
711 | */ | |
712 | static noinline int | |
713 | find_usage_backwards(struct lock_class *source, unsigned int depth) | |
714 | { | |
715 | struct lock_list *entry; | |
716 | int ret; | |
717 | ||
381a2292 JP |
718 | if (!__raw_spin_is_locked(&lockdep_lock)) |
719 | return DEBUG_LOCKS_WARN_ON(1); | |
720 | ||
fbb9ce95 IM |
721 | if (depth > max_recursion_depth) |
722 | max_recursion_depth = depth; | |
ca268c69 | 723 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
724 | return print_infinite_recursion_bug(); |
725 | ||
726 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
727 | if (source->usage_mask & (1 << find_usage_bit)) { | |
728 | backwards_match = source; | |
729 | return 2; | |
730 | } | |
731 | ||
732 | /* | |
733 | * Check this lock's dependency list: | |
734 | */ | |
735 | list_for_each_entry(entry, &source->locks_before, entry) { | |
736 | debug_atomic_inc(&nr_find_usage_backwards_recursions); | |
737 | ret = find_usage_backwards(entry->class, depth+1); | |
738 | if (ret == 2 || ret == 0) | |
739 | return ret; | |
740 | } | |
741 | return 1; | |
742 | } | |
743 | ||
744 | static int | |
745 | print_bad_irq_dependency(struct task_struct *curr, | |
746 | struct held_lock *prev, | |
747 | struct held_lock *next, | |
748 | enum lock_usage_bit bit1, | |
749 | enum lock_usage_bit bit2, | |
750 | const char *irqclass) | |
751 | { | |
74c383f1 | 752 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
753 | return 0; |
754 | ||
755 | printk("\n======================================================\n"); | |
756 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
757 | irqclass, irqclass); | |
99de055a | 758 | print_kernel_version(); |
fbb9ce95 IM |
759 | printk( "------------------------------------------------------\n"); |
760 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
761 | curr->comm, curr->pid, | |
762 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, | |
763 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
764 | curr->hardirqs_enabled, | |
765 | curr->softirqs_enabled); | |
766 | print_lock(next); | |
767 | ||
768 | printk("\nand this task is already holding:\n"); | |
769 | print_lock(prev); | |
770 | printk("which would create a new lock dependency:\n"); | |
771 | print_lock_name(prev->class); | |
772 | printk(" ->"); | |
773 | print_lock_name(next->class); | |
774 | printk("\n"); | |
775 | ||
776 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
777 | irqclass); | |
778 | print_lock_name(backwards_match); | |
779 | printk("\n... which became %s-irq-safe at:\n", irqclass); | |
780 | ||
781 | print_stack_trace(backwards_match->usage_traces + bit1, 1); | |
782 | ||
783 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
784 | print_lock_name(forwards_match); | |
785 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); | |
786 | printk("..."); | |
787 | ||
788 | print_stack_trace(forwards_match->usage_traces + bit2, 1); | |
789 | ||
790 | printk("\nother info that might help us debug this:\n\n"); | |
791 | lockdep_print_held_locks(curr); | |
792 | ||
793 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); | |
794 | print_lock_dependencies(backwards_match, 0); | |
795 | ||
796 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); | |
797 | print_lock_dependencies(forwards_match, 0); | |
798 | ||
799 | printk("\nstack backtrace:\n"); | |
800 | dump_stack(); | |
801 | ||
802 | return 0; | |
803 | } | |
804 | ||
805 | static int | |
806 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
807 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
808 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
809 | { | |
810 | int ret; | |
811 | ||
812 | find_usage_bit = bit_backwards; | |
813 | /* fills in <backwards_match> */ | |
814 | ret = find_usage_backwards(prev->class, 0); | |
815 | if (!ret || ret == 1) | |
816 | return ret; | |
817 | ||
818 | find_usage_bit = bit_forwards; | |
819 | ret = find_usage_forwards(next->class, 0); | |
820 | if (!ret || ret == 1) | |
821 | return ret; | |
822 | /* ret == 2 */ | |
823 | return print_bad_irq_dependency(curr, prev, next, | |
824 | bit_backwards, bit_forwards, irqclass); | |
825 | } | |
826 | ||
827 | #endif | |
828 | ||
829 | static int | |
830 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
831 | struct held_lock *next) | |
832 | { | |
74c383f1 | 833 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
834 | return 0; |
835 | ||
836 | printk("\n=============================================\n"); | |
837 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 838 | print_kernel_version(); |
fbb9ce95 IM |
839 | printk( "---------------------------------------------\n"); |
840 | printk("%s/%d is trying to acquire lock:\n", | |
841 | curr->comm, curr->pid); | |
842 | print_lock(next); | |
843 | printk("\nbut task is already holding lock:\n"); | |
844 | print_lock(prev); | |
845 | ||
846 | printk("\nother info that might help us debug this:\n"); | |
847 | lockdep_print_held_locks(curr); | |
848 | ||
849 | printk("\nstack backtrace:\n"); | |
850 | dump_stack(); | |
851 | ||
852 | return 0; | |
853 | } | |
854 | ||
855 | /* | |
856 | * Check whether we are holding such a class already. | |
857 | * | |
858 | * (Note that this has to be done separately, because the graph cannot | |
859 | * detect such classes of deadlocks.) | |
860 | * | |
861 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
862 | */ | |
863 | static int | |
864 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
865 | struct lockdep_map *next_instance, int read) | |
866 | { | |
867 | struct held_lock *prev; | |
868 | int i; | |
869 | ||
870 | for (i = 0; i < curr->lockdep_depth; i++) { | |
871 | prev = curr->held_locks + i; | |
872 | if (prev->class != next->class) | |
873 | continue; | |
874 | /* | |
875 | * Allow read-after-read recursion of the same | |
6c9076ec | 876 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 877 | */ |
6c9076ec | 878 | if ((read == 2) && prev->read) |
fbb9ce95 IM |
879 | return 2; |
880 | return print_deadlock_bug(curr, prev, next); | |
881 | } | |
882 | return 1; | |
883 | } | |
884 | ||
885 | /* | |
886 | * There was a chain-cache miss, and we are about to add a new dependency | |
887 | * to a previous lock. We recursively validate the following rules: | |
888 | * | |
889 | * - would the adding of the <prev> -> <next> dependency create a | |
890 | * circular dependency in the graph? [== circular deadlock] | |
891 | * | |
892 | * - does the new prev->next dependency connect any hardirq-safe lock | |
893 | * (in the full backwards-subgraph starting at <prev>) with any | |
894 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
895 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
896 | * | |
897 | * - does the new prev->next dependency connect any softirq-safe lock | |
898 | * (in the full backwards-subgraph starting at <prev>) with any | |
899 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
900 | * <next>)? [== illegal lock inversion with softirq contexts] | |
901 | * | |
902 | * any of these scenarios could lead to a deadlock. | |
903 | * | |
904 | * Then if all the validations pass, we add the forwards and backwards | |
905 | * dependency. | |
906 | */ | |
907 | static int | |
908 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 909 | struct held_lock *next, int distance) |
fbb9ce95 IM |
910 | { |
911 | struct lock_list *entry; | |
912 | int ret; | |
913 | ||
914 | /* | |
915 | * Prove that the new <prev> -> <next> dependency would not | |
916 | * create a circular dependency in the graph. (We do this by | |
917 | * forward-recursing into the graph starting at <next>, and | |
918 | * checking whether we can reach <prev>.) | |
919 | * | |
920 | * We are using global variables to control the recursion, to | |
921 | * keep the stackframe size of the recursive functions low: | |
922 | */ | |
923 | check_source = next; | |
924 | check_target = prev; | |
925 | if (!(check_noncircular(next->class, 0))) | |
926 | return print_circular_bug_tail(); | |
927 | ||
928 | #ifdef CONFIG_TRACE_IRQFLAGS | |
929 | /* | |
930 | * Prove that the new dependency does not connect a hardirq-safe | |
931 | * lock with a hardirq-unsafe lock - to achieve this we search | |
932 | * the backwards-subgraph starting at <prev>, and the | |
933 | * forwards-subgraph starting at <next>: | |
934 | */ | |
935 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, | |
936 | LOCK_ENABLED_HARDIRQS, "hard")) | |
937 | return 0; | |
938 | ||
939 | /* | |
940 | * Prove that the new dependency does not connect a hardirq-safe-read | |
941 | * lock with a hardirq-unsafe lock - to achieve this we search | |
942 | * the backwards-subgraph starting at <prev>, and the | |
943 | * forwards-subgraph starting at <next>: | |
944 | */ | |
945 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, | |
946 | LOCK_ENABLED_HARDIRQS, "hard-read")) | |
947 | return 0; | |
948 | ||
949 | /* | |
950 | * Prove that the new dependency does not connect a softirq-safe | |
951 | * lock with a softirq-unsafe lock - to achieve this we search | |
952 | * the backwards-subgraph starting at <prev>, and the | |
953 | * forwards-subgraph starting at <next>: | |
954 | */ | |
955 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, | |
956 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
957 | return 0; | |
958 | /* | |
959 | * Prove that the new dependency does not connect a softirq-safe-read | |
960 | * lock with a softirq-unsafe lock - to achieve this we search | |
961 | * the backwards-subgraph starting at <prev>, and the | |
962 | * forwards-subgraph starting at <next>: | |
963 | */ | |
964 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, | |
965 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
966 | return 0; | |
967 | #endif | |
968 | /* | |
969 | * For recursive read-locks we do all the dependency checks, | |
970 | * but we dont store read-triggered dependencies (only | |
971 | * write-triggered dependencies). This ensures that only the | |
972 | * write-side dependencies matter, and that if for example a | |
973 | * write-lock never takes any other locks, then the reads are | |
974 | * equivalent to a NOP. | |
975 | */ | |
976 | if (next->read == 2 || prev->read == 2) | |
977 | return 1; | |
978 | /* | |
979 | * Is the <prev> -> <next> dependency already present? | |
980 | * | |
981 | * (this may occur even though this is a new chain: consider | |
982 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
983 | * chains - the second one will be new, but L1 already has | |
984 | * L2 added to its dependency list, due to the first chain.) | |
985 | */ | |
986 | list_for_each_entry(entry, &prev->class->locks_after, entry) { | |
068135e6 JB |
987 | if (entry->class == next->class) { |
988 | if (distance == 1) | |
989 | entry->distance = 1; | |
fbb9ce95 | 990 | return 2; |
068135e6 | 991 | } |
fbb9ce95 IM |
992 | } |
993 | ||
994 | /* | |
995 | * Ok, all validations passed, add the new lock | |
996 | * to the previous lock's dependency list: | |
997 | */ | |
998 | ret = add_lock_to_list(prev->class, next->class, | |
068135e6 JB |
999 | &prev->class->locks_after, next->acquire_ip, distance); |
1000 | ||
fbb9ce95 IM |
1001 | if (!ret) |
1002 | return 0; | |
910b1b2e | 1003 | |
fbb9ce95 | 1004 | ret = add_lock_to_list(next->class, prev->class, |
068135e6 | 1005 | &next->class->locks_before, next->acquire_ip, distance); |
910b1b2e JP |
1006 | if (!ret) |
1007 | return 0; | |
fbb9ce95 IM |
1008 | |
1009 | /* | |
1010 | * Debugging printouts: | |
1011 | */ | |
1012 | if (verbose(prev->class) || verbose(next->class)) { | |
74c383f1 | 1013 | graph_unlock(); |
fbb9ce95 IM |
1014 | printk("\n new dependency: "); |
1015 | print_lock_name(prev->class); | |
1016 | printk(" => "); | |
1017 | print_lock_name(next->class); | |
1018 | printk("\n"); | |
1019 | dump_stack(); | |
74c383f1 | 1020 | return graph_lock(); |
fbb9ce95 IM |
1021 | } |
1022 | return 1; | |
1023 | } | |
1024 | ||
1025 | /* | |
1026 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1027 | * The ones that are relevant are (in increasing distance from curr): | |
1028 | * all consecutive trylock entries and the final non-trylock entry - or | |
1029 | * the end of this context's lock-chain - whichever comes first. | |
1030 | */ | |
1031 | static int | |
1032 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1033 | { | |
1034 | int depth = curr->lockdep_depth; | |
1035 | struct held_lock *hlock; | |
1036 | ||
1037 | /* | |
1038 | * Debugging checks. | |
1039 | * | |
1040 | * Depth must not be zero for a non-head lock: | |
1041 | */ | |
1042 | if (!depth) | |
1043 | goto out_bug; | |
1044 | /* | |
1045 | * At least two relevant locks must exist for this | |
1046 | * to be a head: | |
1047 | */ | |
1048 | if (curr->held_locks[depth].irq_context != | |
1049 | curr->held_locks[depth-1].irq_context) | |
1050 | goto out_bug; | |
1051 | ||
1052 | for (;;) { | |
068135e6 | 1053 | int distance = curr->lockdep_depth - depth + 1; |
fbb9ce95 IM |
1054 | hlock = curr->held_locks + depth-1; |
1055 | /* | |
1056 | * Only non-recursive-read entries get new dependencies | |
1057 | * added: | |
1058 | */ | |
1059 | if (hlock->read != 2) { | |
068135e6 | 1060 | if (!check_prev_add(curr, hlock, next, distance)) |
910b1b2e | 1061 | return 0; |
fbb9ce95 IM |
1062 | /* |
1063 | * Stop after the first non-trylock entry, | |
1064 | * as non-trylock entries have added their | |
1065 | * own direct dependencies already, so this | |
1066 | * lock is connected to them indirectly: | |
1067 | */ | |
1068 | if (!hlock->trylock) | |
1069 | break; | |
1070 | } | |
1071 | depth--; | |
1072 | /* | |
1073 | * End of lock-stack? | |
1074 | */ | |
1075 | if (!depth) | |
1076 | break; | |
1077 | /* | |
1078 | * Stop the search if we cross into another context: | |
1079 | */ | |
1080 | if (curr->held_locks[depth].irq_context != | |
1081 | curr->held_locks[depth-1].irq_context) | |
1082 | break; | |
1083 | } | |
1084 | return 1; | |
1085 | out_bug: | |
74c383f1 IM |
1086 | if (!debug_locks_off_graph_unlock()) |
1087 | return 0; | |
1088 | ||
1089 | WARN_ON(1); | |
fbb9ce95 IM |
1090 | |
1091 | return 0; | |
1092 | } | |
1093 | ||
1094 | ||
1095 | /* | |
1096 | * Is this the address of a static object: | |
1097 | */ | |
1098 | static int static_obj(void *obj) | |
1099 | { | |
1100 | unsigned long start = (unsigned long) &_stext, | |
1101 | end = (unsigned long) &_end, | |
1102 | addr = (unsigned long) obj; | |
1103 | #ifdef CONFIG_SMP | |
1104 | int i; | |
1105 | #endif | |
1106 | ||
1107 | /* | |
1108 | * static variable? | |
1109 | */ | |
1110 | if ((addr >= start) && (addr < end)) | |
1111 | return 1; | |
1112 | ||
1113 | #ifdef CONFIG_SMP | |
1114 | /* | |
1115 | * percpu var? | |
1116 | */ | |
1117 | for_each_possible_cpu(i) { | |
1118 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
1ff56830 IM |
1119 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM |
1120 | + per_cpu_offset(i); | |
fbb9ce95 IM |
1121 | |
1122 | if ((addr >= start) && (addr < end)) | |
1123 | return 1; | |
1124 | } | |
1125 | #endif | |
1126 | ||
1127 | /* | |
1128 | * module var? | |
1129 | */ | |
1130 | return is_module_address(addr); | |
1131 | } | |
1132 | ||
1133 | /* | |
1134 | * To make lock name printouts unique, we calculate a unique | |
1135 | * class->name_version generation counter: | |
1136 | */ | |
1137 | static int count_matching_names(struct lock_class *new_class) | |
1138 | { | |
1139 | struct lock_class *class; | |
1140 | int count = 0; | |
1141 | ||
1142 | if (!new_class->name) | |
1143 | return 0; | |
1144 | ||
1145 | list_for_each_entry(class, &all_lock_classes, lock_entry) { | |
1146 | if (new_class->key - new_class->subclass == class->key) | |
1147 | return class->name_version; | |
1148 | if (class->name && !strcmp(class->name, new_class->name)) | |
1149 | count = max(count, class->name_version); | |
1150 | } | |
1151 | ||
1152 | return count + 1; | |
1153 | } | |
1154 | ||
fbb9ce95 IM |
1155 | /* |
1156 | * Register a lock's class in the hash-table, if the class is not present | |
1157 | * yet. Otherwise we look it up. We cache the result in the lock object | |
1158 | * itself, so actual lookup of the hash should be once per lock object. | |
1159 | */ | |
1160 | static inline struct lock_class * | |
d6d897ce | 1161 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) |
fbb9ce95 IM |
1162 | { |
1163 | struct lockdep_subclass_key *key; | |
1164 | struct list_head *hash_head; | |
1165 | struct lock_class *class; | |
1166 | ||
1167 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1168 | /* | |
1169 | * If the architecture calls into lockdep before initializing | |
1170 | * the hashes then we'll warn about it later. (we cannot printk | |
1171 | * right now) | |
1172 | */ | |
1173 | if (unlikely(!lockdep_initialized)) { | |
1174 | lockdep_init(); | |
1175 | lockdep_init_error = 1; | |
1176 | } | |
1177 | #endif | |
1178 | ||
1179 | /* | |
1180 | * Static locks do not have their class-keys yet - for them the key | |
1181 | * is the lock object itself: | |
1182 | */ | |
1183 | if (unlikely(!lock->key)) | |
1184 | lock->key = (void *)lock; | |
1185 | ||
1186 | /* | |
1187 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
1188 | * lock_class_key variable is passed in through the mutex_init() | |
1189 | * (or spin_lock_init()) call - which acts as the key. For static | |
1190 | * locks we use the lock object itself as the key. | |
1191 | */ | |
3dc3099a | 1192 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class)); |
fbb9ce95 IM |
1193 | |
1194 | key = lock->key->subkeys + subclass; | |
1195 | ||
1196 | hash_head = classhashentry(key); | |
1197 | ||
1198 | /* | |
1199 | * We can walk the hash lockfree, because the hash only | |
1200 | * grows, and we are careful when adding entries to the end: | |
1201 | */ | |
1202 | list_for_each_entry(class, hash_head, hash_entry) | |
1203 | if (class->key == key) | |
d6d897ce IM |
1204 | return class; |
1205 | ||
1206 | return NULL; | |
1207 | } | |
1208 | ||
1209 | /* | |
1210 | * Register a lock's class in the hash-table, if the class is not present | |
1211 | * yet. Otherwise we look it up. We cache the result in the lock object | |
1212 | * itself, so actual lookup of the hash should be once per lock object. | |
1213 | */ | |
1214 | static inline struct lock_class * | |
4dfbb9d8 | 1215 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
d6d897ce IM |
1216 | { |
1217 | struct lockdep_subclass_key *key; | |
1218 | struct list_head *hash_head; | |
1219 | struct lock_class *class; | |
70e45067 | 1220 | unsigned long flags; |
d6d897ce IM |
1221 | |
1222 | class = look_up_lock_class(lock, subclass); | |
1223 | if (likely(class)) | |
1224 | return class; | |
fbb9ce95 IM |
1225 | |
1226 | /* | |
1227 | * Debug-check: all keys must be persistent! | |
1228 | */ | |
1229 | if (!static_obj(lock->key)) { | |
1230 | debug_locks_off(); | |
1231 | printk("INFO: trying to register non-static key.\n"); | |
1232 | printk("the code is fine but needs lockdep annotation.\n"); | |
1233 | printk("turning off the locking correctness validator.\n"); | |
1234 | dump_stack(); | |
1235 | ||
1236 | return NULL; | |
1237 | } | |
1238 | ||
d6d897ce IM |
1239 | key = lock->key->subkeys + subclass; |
1240 | hash_head = classhashentry(key); | |
1241 | ||
70e45067 | 1242 | raw_local_irq_save(flags); |
74c383f1 IM |
1243 | if (!graph_lock()) { |
1244 | raw_local_irq_restore(flags); | |
1245 | return NULL; | |
1246 | } | |
fbb9ce95 IM |
1247 | /* |
1248 | * We have to do the hash-walk again, to avoid races | |
1249 | * with another CPU: | |
1250 | */ | |
1251 | list_for_each_entry(class, hash_head, hash_entry) | |
1252 | if (class->key == key) | |
1253 | goto out_unlock_set; | |
1254 | /* | |
1255 | * Allocate a new key from the static array, and add it to | |
1256 | * the hash: | |
1257 | */ | |
1258 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
74c383f1 IM |
1259 | if (!debug_locks_off_graph_unlock()) { |
1260 | raw_local_irq_restore(flags); | |
1261 | return NULL; | |
1262 | } | |
70e45067 | 1263 | raw_local_irq_restore(flags); |
74c383f1 | 1264 | |
fbb9ce95 IM |
1265 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); |
1266 | printk("turning off the locking correctness validator.\n"); | |
1267 | return NULL; | |
1268 | } | |
1269 | class = lock_classes + nr_lock_classes++; | |
1270 | debug_atomic_inc(&nr_unused_locks); | |
1271 | class->key = key; | |
1272 | class->name = lock->name; | |
1273 | class->subclass = subclass; | |
1274 | INIT_LIST_HEAD(&class->lock_entry); | |
1275 | INIT_LIST_HEAD(&class->locks_before); | |
1276 | INIT_LIST_HEAD(&class->locks_after); | |
1277 | class->name_version = count_matching_names(class); | |
1278 | /* | |
1279 | * We use RCU's safe list-add method to make | |
1280 | * parallel walking of the hash-list safe: | |
1281 | */ | |
1282 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1283 | ||
1284 | if (verbose(class)) { | |
74c383f1 | 1285 | graph_unlock(); |
70e45067 | 1286 | raw_local_irq_restore(flags); |
74c383f1 | 1287 | |
fbb9ce95 IM |
1288 | printk("\nnew class %p: %s", class->key, class->name); |
1289 | if (class->name_version > 1) | |
1290 | printk("#%d", class->name_version); | |
1291 | printk("\n"); | |
1292 | dump_stack(); | |
74c383f1 | 1293 | |
70e45067 | 1294 | raw_local_irq_save(flags); |
74c383f1 IM |
1295 | if (!graph_lock()) { |
1296 | raw_local_irq_restore(flags); | |
1297 | return NULL; | |
1298 | } | |
fbb9ce95 IM |
1299 | } |
1300 | out_unlock_set: | |
74c383f1 | 1301 | graph_unlock(); |
70e45067 | 1302 | raw_local_irq_restore(flags); |
fbb9ce95 | 1303 | |
4dfbb9d8 | 1304 | if (!subclass || force) |
d6d897ce | 1305 | lock->class_cache = class; |
fbb9ce95 | 1306 | |
381a2292 JP |
1307 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
1308 | return NULL; | |
fbb9ce95 IM |
1309 | |
1310 | return class; | |
1311 | } | |
1312 | ||
1313 | /* | |
1314 | * Look up a dependency chain. If the key is not present yet then | |
1315 | * add it and return 0 - in this case the new dependency chain is | |
1316 | * validated. If the key is already hashed, return 1. | |
1317 | */ | |
81fc685a | 1318 | static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class) |
fbb9ce95 IM |
1319 | { |
1320 | struct list_head *hash_head = chainhashentry(chain_key); | |
1321 | struct lock_chain *chain; | |
1322 | ||
381a2292 JP |
1323 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1324 | return 0; | |
fbb9ce95 IM |
1325 | /* |
1326 | * We can walk it lock-free, because entries only get added | |
1327 | * to the hash: | |
1328 | */ | |
1329 | list_for_each_entry(chain, hash_head, entry) { | |
1330 | if (chain->chain_key == chain_key) { | |
1331 | cache_hit: | |
1332 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1333 | if (very_verbose(class)) |
755cd900 AM |
1334 | printk("\nhash chain already cached, key: " |
1335 | "%016Lx tail class: [%p] %s\n", | |
1336 | (unsigned long long)chain_key, | |
1337 | class->key, class->name); | |
fbb9ce95 IM |
1338 | return 0; |
1339 | } | |
1340 | } | |
81fc685a | 1341 | if (very_verbose(class)) |
755cd900 AM |
1342 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1343 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1344 | /* |
1345 | * Allocate a new chain entry from the static array, and add | |
1346 | * it to the hash: | |
1347 | */ | |
74c383f1 IM |
1348 | if (!graph_lock()) |
1349 | return 0; | |
fbb9ce95 IM |
1350 | /* |
1351 | * We have to walk the chain again locked - to avoid duplicates: | |
1352 | */ | |
1353 | list_for_each_entry(chain, hash_head, entry) { | |
1354 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1355 | graph_unlock(); |
fbb9ce95 IM |
1356 | goto cache_hit; |
1357 | } | |
1358 | } | |
1359 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1360 | if (!debug_locks_off_graph_unlock()) |
1361 | return 0; | |
1362 | ||
fbb9ce95 IM |
1363 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1364 | printk("turning off the locking correctness validator.\n"); | |
1365 | return 0; | |
1366 | } | |
1367 | chain = lock_chains + nr_lock_chains++; | |
1368 | chain->chain_key = chain_key; | |
1369 | list_add_tail_rcu(&chain->entry, hash_head); | |
1370 | debug_atomic_inc(&chain_lookup_misses); | |
1371 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1372 | if (current->hardirq_context) | |
1373 | nr_hardirq_chains++; | |
1374 | else { | |
1375 | if (current->softirq_context) | |
1376 | nr_softirq_chains++; | |
1377 | else | |
1378 | nr_process_chains++; | |
1379 | } | |
1380 | #else | |
1381 | nr_process_chains++; | |
1382 | #endif | |
1383 | ||
1384 | return 1; | |
1385 | } | |
1386 | ||
1387 | /* | |
1388 | * We are building curr_chain_key incrementally, so double-check | |
1389 | * it from scratch, to make sure that it's done correctly: | |
1390 | */ | |
1391 | static void check_chain_key(struct task_struct *curr) | |
1392 | { | |
1393 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1394 | struct held_lock *hlock, *prev_hlock = NULL; | |
1395 | unsigned int i, id; | |
1396 | u64 chain_key = 0; | |
1397 | ||
1398 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1399 | hlock = curr->held_locks + i; | |
1400 | if (chain_key != hlock->prev_chain_key) { | |
1401 | debug_locks_off(); | |
1402 | printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n", | |
1403 | curr->lockdep_depth, i, | |
1404 | (unsigned long long)chain_key, | |
1405 | (unsigned long long)hlock->prev_chain_key); | |
1406 | WARN_ON(1); | |
1407 | return; | |
1408 | } | |
1409 | id = hlock->class - lock_classes; | |
381a2292 JP |
1410 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1411 | return; | |
1412 | ||
fbb9ce95 IM |
1413 | if (prev_hlock && (prev_hlock->irq_context != |
1414 | hlock->irq_context)) | |
1415 | chain_key = 0; | |
1416 | chain_key = iterate_chain_key(chain_key, id); | |
1417 | prev_hlock = hlock; | |
1418 | } | |
1419 | if (chain_key != curr->curr_chain_key) { | |
1420 | debug_locks_off(); | |
1421 | printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n", | |
1422 | curr->lockdep_depth, i, | |
1423 | (unsigned long long)chain_key, | |
1424 | (unsigned long long)curr->curr_chain_key); | |
1425 | WARN_ON(1); | |
1426 | } | |
1427 | #endif | |
1428 | } | |
1429 | ||
1430 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1431 | ||
1432 | /* | |
1433 | * print irq inversion bug: | |
1434 | */ | |
1435 | static int | |
1436 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, | |
1437 | struct held_lock *this, int forwards, | |
1438 | const char *irqclass) | |
1439 | { | |
74c383f1 | 1440 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1441 | return 0; |
1442 | ||
1443 | printk("\n=========================================================\n"); | |
1444 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 1445 | print_kernel_version(); |
fbb9ce95 IM |
1446 | printk( "---------------------------------------------------------\n"); |
1447 | printk("%s/%d just changed the state of lock:\n", | |
1448 | curr->comm, curr->pid); | |
1449 | print_lock(this); | |
1450 | if (forwards) | |
1451 | printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass); | |
1452 | else | |
1453 | printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass); | |
1454 | print_lock_name(other); | |
1455 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); | |
1456 | ||
1457 | printk("\nother info that might help us debug this:\n"); | |
1458 | lockdep_print_held_locks(curr); | |
1459 | ||
1460 | printk("\nthe first lock's dependencies:\n"); | |
1461 | print_lock_dependencies(this->class, 0); | |
1462 | ||
1463 | printk("\nthe second lock's dependencies:\n"); | |
1464 | print_lock_dependencies(other, 0); | |
1465 | ||
1466 | printk("\nstack backtrace:\n"); | |
1467 | dump_stack(); | |
1468 | ||
1469 | return 0; | |
1470 | } | |
1471 | ||
1472 | /* | |
1473 | * Prove that in the forwards-direction subgraph starting at <this> | |
1474 | * there is no lock matching <mask>: | |
1475 | */ | |
1476 | static int | |
1477 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
1478 | enum lock_usage_bit bit, const char *irqclass) | |
1479 | { | |
1480 | int ret; | |
1481 | ||
1482 | find_usage_bit = bit; | |
1483 | /* fills in <forwards_match> */ | |
1484 | ret = find_usage_forwards(this->class, 0); | |
1485 | if (!ret || ret == 1) | |
1486 | return ret; | |
1487 | ||
1488 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); | |
1489 | } | |
1490 | ||
1491 | /* | |
1492 | * Prove that in the backwards-direction subgraph starting at <this> | |
1493 | * there is no lock matching <mask>: | |
1494 | */ | |
1495 | static int | |
1496 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
1497 | enum lock_usage_bit bit, const char *irqclass) | |
1498 | { | |
1499 | int ret; | |
1500 | ||
1501 | find_usage_bit = bit; | |
1502 | /* fills in <backwards_match> */ | |
1503 | ret = find_usage_backwards(this->class, 0); | |
1504 | if (!ret || ret == 1) | |
1505 | return ret; | |
1506 | ||
1507 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); | |
1508 | } | |
1509 | ||
3117df04 | 1510 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
1511 | { |
1512 | printk("irq event stamp: %u\n", curr->irq_events); | |
1513 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
1514 | print_ip_sym(curr->hardirq_enable_ip); | |
1515 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
1516 | print_ip_sym(curr->hardirq_disable_ip); | |
1517 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
1518 | print_ip_sym(curr->softirq_enable_ip); | |
1519 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
1520 | print_ip_sym(curr->softirq_disable_ip); | |
1521 | } | |
1522 | ||
fbb9ce95 IM |
1523 | #endif |
1524 | ||
1525 | static int | |
1526 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1527 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1528 | { | |
74c383f1 | 1529 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1530 | return 0; |
1531 | ||
1532 | printk("\n=================================\n"); | |
1533 | printk( "[ INFO: inconsistent lock state ]\n"); | |
99de055a | 1534 | print_kernel_version(); |
fbb9ce95 IM |
1535 | printk( "---------------------------------\n"); |
1536 | ||
1537 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1538 | usage_str[prev_bit], usage_str[new_bit]); | |
1539 | ||
1540 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
1541 | curr->comm, curr->pid, | |
1542 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, | |
1543 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1544 | trace_hardirqs_enabled(curr), | |
1545 | trace_softirqs_enabled(curr)); | |
1546 | print_lock(this); | |
1547 | ||
1548 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
1549 | print_stack_trace(this->class->usage_traces + prev_bit, 1); | |
1550 | ||
1551 | print_irqtrace_events(curr); | |
1552 | printk("\nother info that might help us debug this:\n"); | |
1553 | lockdep_print_held_locks(curr); | |
1554 | ||
1555 | printk("\nstack backtrace:\n"); | |
1556 | dump_stack(); | |
1557 | ||
1558 | return 0; | |
1559 | } | |
1560 | ||
1561 | /* | |
1562 | * Print out an error if an invalid bit is set: | |
1563 | */ | |
1564 | static inline int | |
1565 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1566 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1567 | { | |
1568 | if (unlikely(this->class->usage_mask & (1 << bad_bit))) | |
1569 | return print_usage_bug(curr, this, bad_bit, new_bit); | |
1570 | return 1; | |
1571 | } | |
1572 | ||
1573 | #define STRICT_READ_CHECKS 1 | |
1574 | ||
1575 | /* | |
1576 | * Mark a lock with a usage bit, and validate the state transition: | |
1577 | */ | |
1578 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
1579 | enum lock_usage_bit new_bit, unsigned long ip) | |
1580 | { | |
1581 | unsigned int new_mask = 1 << new_bit, ret = 1; | |
1582 | ||
1583 | /* | |
1584 | * If already set then do not dirty the cacheline, | |
1585 | * nor do any checks: | |
1586 | */ | |
1587 | if (likely(this->class->usage_mask & new_mask)) | |
1588 | return 1; | |
1589 | ||
74c383f1 IM |
1590 | if (!graph_lock()) |
1591 | return 0; | |
fbb9ce95 IM |
1592 | /* |
1593 | * Make sure we didnt race: | |
1594 | */ | |
1595 | if (unlikely(this->class->usage_mask & new_mask)) { | |
74c383f1 | 1596 | graph_unlock(); |
fbb9ce95 IM |
1597 | return 1; |
1598 | } | |
1599 | ||
1600 | this->class->usage_mask |= new_mask; | |
1601 | ||
1602 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1603 | if (new_bit == LOCK_ENABLED_HARDIRQS || | |
1604 | new_bit == LOCK_ENABLED_HARDIRQS_READ) | |
1605 | ip = curr->hardirq_enable_ip; | |
1606 | else if (new_bit == LOCK_ENABLED_SOFTIRQS || | |
1607 | new_bit == LOCK_ENABLED_SOFTIRQS_READ) | |
1608 | ip = curr->softirq_enable_ip; | |
1609 | #endif | |
1610 | if (!save_trace(this->class->usage_traces + new_bit)) | |
1611 | return 0; | |
1612 | ||
1613 | switch (new_bit) { | |
1614 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1615 | case LOCK_USED_IN_HARDIRQ: | |
1616 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1617 | return 0; | |
1618 | if (!valid_state(curr, this, new_bit, | |
1619 | LOCK_ENABLED_HARDIRQS_READ)) | |
1620 | return 0; | |
1621 | /* | |
1622 | * just marked it hardirq-safe, check that this lock | |
1623 | * took no hardirq-unsafe lock in the past: | |
1624 | */ | |
1625 | if (!check_usage_forwards(curr, this, | |
1626 | LOCK_ENABLED_HARDIRQS, "hard")) | |
1627 | return 0; | |
1628 | #if STRICT_READ_CHECKS | |
1629 | /* | |
1630 | * just marked it hardirq-safe, check that this lock | |
1631 | * took no hardirq-unsafe-read lock in the past: | |
1632 | */ | |
1633 | if (!check_usage_forwards(curr, this, | |
1634 | LOCK_ENABLED_HARDIRQS_READ, "hard-read")) | |
1635 | return 0; | |
1636 | #endif | |
1637 | if (hardirq_verbose(this->class)) | |
1638 | ret = 2; | |
1639 | break; | |
1640 | case LOCK_USED_IN_SOFTIRQ: | |
1641 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1642 | return 0; | |
1643 | if (!valid_state(curr, this, new_bit, | |
1644 | LOCK_ENABLED_SOFTIRQS_READ)) | |
1645 | return 0; | |
1646 | /* | |
1647 | * just marked it softirq-safe, check that this lock | |
1648 | * took no softirq-unsafe lock in the past: | |
1649 | */ | |
1650 | if (!check_usage_forwards(curr, this, | |
1651 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1652 | return 0; | |
1653 | #if STRICT_READ_CHECKS | |
1654 | /* | |
1655 | * just marked it softirq-safe, check that this lock | |
1656 | * took no softirq-unsafe-read lock in the past: | |
1657 | */ | |
1658 | if (!check_usage_forwards(curr, this, | |
1659 | LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) | |
1660 | return 0; | |
1661 | #endif | |
1662 | if (softirq_verbose(this->class)) | |
1663 | ret = 2; | |
1664 | break; | |
1665 | case LOCK_USED_IN_HARDIRQ_READ: | |
1666 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | |
1667 | return 0; | |
1668 | /* | |
1669 | * just marked it hardirq-read-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 (hardirq_verbose(this->class)) | |
1676 | ret = 2; | |
1677 | break; | |
1678 | case LOCK_USED_IN_SOFTIRQ_READ: | |
1679 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) | |
1680 | return 0; | |
1681 | /* | |
1682 | * just marked it softirq-read-safe, check that this lock | |
1683 | * took no softirq-unsafe lock in the past: | |
1684 | */ | |
1685 | if (!check_usage_forwards(curr, this, | |
1686 | LOCK_ENABLED_SOFTIRQS, "soft")) | |
1687 | return 0; | |
1688 | if (softirq_verbose(this->class)) | |
1689 | ret = 2; | |
1690 | break; | |
1691 | case LOCK_ENABLED_HARDIRQS: | |
1692 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
1693 | return 0; | |
1694 | if (!valid_state(curr, this, new_bit, | |
1695 | LOCK_USED_IN_HARDIRQ_READ)) | |
1696 | return 0; | |
1697 | /* | |
1698 | * just marked it hardirq-unsafe, check that no hardirq-safe | |
1699 | * lock in the system ever took it in the past: | |
1700 | */ | |
1701 | if (!check_usage_backwards(curr, this, | |
1702 | LOCK_USED_IN_HARDIRQ, "hard")) | |
1703 | return 0; | |
1704 | #if STRICT_READ_CHECKS | |
1705 | /* | |
1706 | * just marked it hardirq-unsafe, check that no | |
1707 | * hardirq-safe-read lock in the system ever took | |
1708 | * it in the past: | |
1709 | */ | |
1710 | if (!check_usage_backwards(curr, this, | |
1711 | LOCK_USED_IN_HARDIRQ_READ, "hard-read")) | |
1712 | return 0; | |
1713 | #endif | |
1714 | if (hardirq_verbose(this->class)) | |
1715 | ret = 2; | |
1716 | break; | |
1717 | case LOCK_ENABLED_SOFTIRQS: | |
1718 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
1719 | return 0; | |
1720 | if (!valid_state(curr, this, new_bit, | |
1721 | LOCK_USED_IN_SOFTIRQ_READ)) | |
1722 | return 0; | |
1723 | /* | |
1724 | * just marked it softirq-unsafe, check that no softirq-safe | |
1725 | * lock in the system ever took it in the past: | |
1726 | */ | |
1727 | if (!check_usage_backwards(curr, this, | |
1728 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
1729 | return 0; | |
1730 | #if STRICT_READ_CHECKS | |
1731 | /* | |
1732 | * just marked it softirq-unsafe, check that no | |
1733 | * softirq-safe-read lock in the system ever took | |
1734 | * it in the past: | |
1735 | */ | |
1736 | if (!check_usage_backwards(curr, this, | |
1737 | LOCK_USED_IN_SOFTIRQ_READ, "soft-read")) | |
1738 | return 0; | |
1739 | #endif | |
1740 | if (softirq_verbose(this->class)) | |
1741 | ret = 2; | |
1742 | break; | |
1743 | case LOCK_ENABLED_HARDIRQS_READ: | |
1744 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) | |
1745 | return 0; | |
1746 | #if STRICT_READ_CHECKS | |
1747 | /* | |
1748 | * just marked it hardirq-read-unsafe, check that no | |
1749 | * hardirq-safe lock in the system ever took it in the past: | |
1750 | */ | |
1751 | if (!check_usage_backwards(curr, this, | |
1752 | LOCK_USED_IN_HARDIRQ, "hard")) | |
1753 | return 0; | |
1754 | #endif | |
1755 | if (hardirq_verbose(this->class)) | |
1756 | ret = 2; | |
1757 | break; | |
1758 | case LOCK_ENABLED_SOFTIRQS_READ: | |
1759 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) | |
1760 | return 0; | |
1761 | #if STRICT_READ_CHECKS | |
1762 | /* | |
1763 | * just marked it softirq-read-unsafe, check that no | |
1764 | * softirq-safe lock in the system ever took it in the past: | |
1765 | */ | |
1766 | if (!check_usage_backwards(curr, this, | |
1767 | LOCK_USED_IN_SOFTIRQ, "soft")) | |
1768 | return 0; | |
1769 | #endif | |
1770 | if (softirq_verbose(this->class)) | |
1771 | ret = 2; | |
1772 | break; | |
1773 | #endif | |
1774 | case LOCK_USED: | |
1775 | /* | |
1776 | * Add it to the global list of classes: | |
1777 | */ | |
1778 | list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes); | |
1779 | debug_atomic_dec(&nr_unused_locks); | |
1780 | break; | |
1781 | default: | |
74c383f1 IM |
1782 | if (!debug_locks_off_graph_unlock()) |
1783 | return 0; | |
fbb9ce95 IM |
1784 | WARN_ON(1); |
1785 | return 0; | |
1786 | } | |
1787 | ||
74c383f1 | 1788 | graph_unlock(); |
fbb9ce95 IM |
1789 | |
1790 | /* | |
74c383f1 | 1791 | * We must printk outside of the graph_lock: |
fbb9ce95 IM |
1792 | */ |
1793 | if (ret == 2) { | |
1794 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
1795 | print_lock(this); | |
1796 | print_irqtrace_events(curr); | |
1797 | dump_stack(); | |
1798 | } | |
1799 | ||
1800 | return ret; | |
1801 | } | |
1802 | ||
1803 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1804 | /* | |
1805 | * Mark all held locks with a usage bit: | |
1806 | */ | |
1807 | static int | |
1808 | mark_held_locks(struct task_struct *curr, int hardirq, unsigned long ip) | |
1809 | { | |
1810 | enum lock_usage_bit usage_bit; | |
1811 | struct held_lock *hlock; | |
1812 | int i; | |
1813 | ||
1814 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1815 | hlock = curr->held_locks + i; | |
1816 | ||
1817 | if (hardirq) { | |
1818 | if (hlock->read) | |
1819 | usage_bit = LOCK_ENABLED_HARDIRQS_READ; | |
1820 | else | |
1821 | usage_bit = LOCK_ENABLED_HARDIRQS; | |
1822 | } else { | |
1823 | if (hlock->read) | |
1824 | usage_bit = LOCK_ENABLED_SOFTIRQS_READ; | |
1825 | else | |
1826 | usage_bit = LOCK_ENABLED_SOFTIRQS; | |
1827 | } | |
1828 | if (!mark_lock(curr, hlock, usage_bit, ip)) | |
1829 | return 0; | |
1830 | } | |
1831 | ||
1832 | return 1; | |
1833 | } | |
1834 | ||
1835 | /* | |
1836 | * Debugging helper: via this flag we know that we are in | |
1837 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
1838 | */ | |
1839 | static int early_boot_irqs_enabled; | |
1840 | ||
1841 | void early_boot_irqs_off(void) | |
1842 | { | |
1843 | early_boot_irqs_enabled = 0; | |
1844 | } | |
1845 | ||
1846 | void early_boot_irqs_on(void) | |
1847 | { | |
1848 | early_boot_irqs_enabled = 1; | |
1849 | } | |
1850 | ||
1851 | /* | |
1852 | * Hardirqs will be enabled: | |
1853 | */ | |
1854 | void trace_hardirqs_on(void) | |
1855 | { | |
1856 | struct task_struct *curr = current; | |
1857 | unsigned long ip; | |
1858 | ||
1859 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
1860 | return; | |
1861 | ||
1862 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
1863 | return; | |
1864 | ||
1865 | if (unlikely(curr->hardirqs_enabled)) { | |
1866 | debug_atomic_inc(&redundant_hardirqs_on); | |
1867 | return; | |
1868 | } | |
1869 | /* we'll do an OFF -> ON transition: */ | |
1870 | curr->hardirqs_enabled = 1; | |
1871 | ip = (unsigned long) __builtin_return_address(0); | |
1872 | ||
1873 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1874 | return; | |
1875 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
1876 | return; | |
1877 | /* | |
1878 | * We are going to turn hardirqs on, so set the | |
1879 | * usage bit for all held locks: | |
1880 | */ | |
1881 | if (!mark_held_locks(curr, 1, ip)) | |
1882 | return; | |
1883 | /* | |
1884 | * If we have softirqs enabled, then set the usage | |
1885 | * bit for all held locks. (disabled hardirqs prevented | |
1886 | * this bit from being set before) | |
1887 | */ | |
1888 | if (curr->softirqs_enabled) | |
1889 | if (!mark_held_locks(curr, 0, ip)) | |
1890 | return; | |
1891 | ||
1892 | curr->hardirq_enable_ip = ip; | |
1893 | curr->hardirq_enable_event = ++curr->irq_events; | |
1894 | debug_atomic_inc(&hardirqs_on_events); | |
1895 | } | |
1896 | ||
1897 | EXPORT_SYMBOL(trace_hardirqs_on); | |
1898 | ||
1899 | /* | |
1900 | * Hardirqs were disabled: | |
1901 | */ | |
1902 | void trace_hardirqs_off(void) | |
1903 | { | |
1904 | struct task_struct *curr = current; | |
1905 | ||
1906 | if (unlikely(!debug_locks || current->lockdep_recursion)) | |
1907 | return; | |
1908 | ||
1909 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1910 | return; | |
1911 | ||
1912 | if (curr->hardirqs_enabled) { | |
1913 | /* | |
1914 | * We have done an ON -> OFF transition: | |
1915 | */ | |
1916 | curr->hardirqs_enabled = 0; | |
1917 | curr->hardirq_disable_ip = _RET_IP_; | |
1918 | curr->hardirq_disable_event = ++curr->irq_events; | |
1919 | debug_atomic_inc(&hardirqs_off_events); | |
1920 | } else | |
1921 | debug_atomic_inc(&redundant_hardirqs_off); | |
1922 | } | |
1923 | ||
1924 | EXPORT_SYMBOL(trace_hardirqs_off); | |
1925 | ||
1926 | /* | |
1927 | * Softirqs will be enabled: | |
1928 | */ | |
1929 | void trace_softirqs_on(unsigned long ip) | |
1930 | { | |
1931 | struct task_struct *curr = current; | |
1932 | ||
1933 | if (unlikely(!debug_locks)) | |
1934 | return; | |
1935 | ||
1936 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1937 | return; | |
1938 | ||
1939 | if (curr->softirqs_enabled) { | |
1940 | debug_atomic_inc(&redundant_softirqs_on); | |
1941 | return; | |
1942 | } | |
1943 | ||
1944 | /* | |
1945 | * We'll do an OFF -> ON transition: | |
1946 | */ | |
1947 | curr->softirqs_enabled = 1; | |
1948 | curr->softirq_enable_ip = ip; | |
1949 | curr->softirq_enable_event = ++curr->irq_events; | |
1950 | debug_atomic_inc(&softirqs_on_events); | |
1951 | /* | |
1952 | * We are going to turn softirqs on, so set the | |
1953 | * usage bit for all held locks, if hardirqs are | |
1954 | * enabled too: | |
1955 | */ | |
1956 | if (curr->hardirqs_enabled) | |
1957 | mark_held_locks(curr, 0, ip); | |
1958 | } | |
1959 | ||
1960 | /* | |
1961 | * Softirqs were disabled: | |
1962 | */ | |
1963 | void trace_softirqs_off(unsigned long ip) | |
1964 | { | |
1965 | struct task_struct *curr = current; | |
1966 | ||
1967 | if (unlikely(!debug_locks)) | |
1968 | return; | |
1969 | ||
1970 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
1971 | return; | |
1972 | ||
1973 | if (curr->softirqs_enabled) { | |
1974 | /* | |
1975 | * We have done an ON -> OFF transition: | |
1976 | */ | |
1977 | curr->softirqs_enabled = 0; | |
1978 | curr->softirq_disable_ip = ip; | |
1979 | curr->softirq_disable_event = ++curr->irq_events; | |
1980 | debug_atomic_inc(&softirqs_off_events); | |
1981 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
1982 | } else | |
1983 | debug_atomic_inc(&redundant_softirqs_off); | |
1984 | } | |
1985 | ||
1986 | #endif | |
1987 | ||
1988 | /* | |
1989 | * Initialize a lock instance's lock-class mapping info: | |
1990 | */ | |
1991 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 1992 | struct lock_class_key *key, int subclass) |
fbb9ce95 IM |
1993 | { |
1994 | if (unlikely(!debug_locks)) | |
1995 | return; | |
1996 | ||
1997 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
1998 | return; | |
1999 | if (DEBUG_LOCKS_WARN_ON(!name)) | |
2000 | return; | |
2001 | /* | |
2002 | * Sanity check, the lock-class key must be persistent: | |
2003 | */ | |
2004 | if (!static_obj(key)) { | |
2005 | printk("BUG: key %p not in .data!\n", key); | |
2006 | DEBUG_LOCKS_WARN_ON(1); | |
2007 | return; | |
2008 | } | |
2009 | lock->name = name; | |
2010 | lock->key = key; | |
d6d897ce | 2011 | lock->class_cache = NULL; |
4dfbb9d8 PZ |
2012 | if (subclass) |
2013 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 IM |
2014 | } |
2015 | ||
2016 | EXPORT_SYMBOL_GPL(lockdep_init_map); | |
2017 | ||
2018 | /* | |
2019 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2020 | * We maintain the dependency maps and validate the locking attempt: | |
2021 | */ | |
2022 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2023 | int trylock, int read, int check, int hardirqs_off, | |
2024 | unsigned long ip) | |
2025 | { | |
2026 | struct task_struct *curr = current; | |
d6d897ce | 2027 | struct lock_class *class = NULL; |
fbb9ce95 | 2028 | struct held_lock *hlock; |
fbb9ce95 IM |
2029 | unsigned int depth, id; |
2030 | int chain_head = 0; | |
2031 | u64 chain_key; | |
2032 | ||
2033 | if (unlikely(!debug_locks)) | |
2034 | return 0; | |
2035 | ||
2036 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2037 | return 0; | |
2038 | ||
2039 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2040 | debug_locks_off(); | |
2041 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2042 | printk("turning off the locking correctness validator.\n"); | |
2043 | return 0; | |
2044 | } | |
2045 | ||
d6d897ce IM |
2046 | if (!subclass) |
2047 | class = lock->class_cache; | |
2048 | /* | |
2049 | * Not cached yet or subclass? | |
2050 | */ | |
fbb9ce95 | 2051 | if (unlikely(!class)) { |
4dfbb9d8 | 2052 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2053 | if (!class) |
2054 | return 0; | |
2055 | } | |
2056 | debug_atomic_inc((atomic_t *)&class->ops); | |
2057 | if (very_verbose(class)) { | |
2058 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2059 | if (class->name_version > 1) | |
2060 | printk("#%d", class->name_version); | |
2061 | printk("\n"); | |
2062 | dump_stack(); | |
2063 | } | |
2064 | ||
2065 | /* | |
2066 | * Add the lock to the list of currently held locks. | |
2067 | * (we dont increase the depth just yet, up until the | |
2068 | * dependency checks are done) | |
2069 | */ | |
2070 | depth = curr->lockdep_depth; | |
2071 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2072 | return 0; | |
2073 | ||
2074 | hlock = curr->held_locks + depth; | |
2075 | ||
2076 | hlock->class = class; | |
2077 | hlock->acquire_ip = ip; | |
2078 | hlock->instance = lock; | |
2079 | hlock->trylock = trylock; | |
2080 | hlock->read = read; | |
2081 | hlock->check = check; | |
2082 | hlock->hardirqs_off = hardirqs_off; | |
2083 | ||
2084 | if (check != 2) | |
2085 | goto out_calc_hash; | |
2086 | #ifdef CONFIG_TRACE_IRQFLAGS | |
2087 | /* | |
2088 | * If non-trylock use in a hardirq or softirq context, then | |
2089 | * mark the lock as used in these contexts: | |
2090 | */ | |
2091 | if (!trylock) { | |
2092 | if (read) { | |
2093 | if (curr->hardirq_context) | |
2094 | if (!mark_lock(curr, hlock, | |
2095 | LOCK_USED_IN_HARDIRQ_READ, ip)) | |
2096 | return 0; | |
2097 | if (curr->softirq_context) | |
2098 | if (!mark_lock(curr, hlock, | |
2099 | LOCK_USED_IN_SOFTIRQ_READ, ip)) | |
2100 | return 0; | |
2101 | } else { | |
2102 | if (curr->hardirq_context) | |
2103 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ, ip)) | |
2104 | return 0; | |
2105 | if (curr->softirq_context) | |
2106 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ, ip)) | |
2107 | return 0; | |
2108 | } | |
2109 | } | |
2110 | if (!hardirqs_off) { | |
2111 | if (read) { | |
2112 | if (!mark_lock(curr, hlock, | |
2113 | LOCK_ENABLED_HARDIRQS_READ, ip)) | |
2114 | return 0; | |
2115 | if (curr->softirqs_enabled) | |
2116 | if (!mark_lock(curr, hlock, | |
2117 | LOCK_ENABLED_SOFTIRQS_READ, ip)) | |
2118 | return 0; | |
2119 | } else { | |
2120 | if (!mark_lock(curr, hlock, | |
2121 | LOCK_ENABLED_HARDIRQS, ip)) | |
2122 | return 0; | |
2123 | if (curr->softirqs_enabled) | |
2124 | if (!mark_lock(curr, hlock, | |
2125 | LOCK_ENABLED_SOFTIRQS, ip)) | |
2126 | return 0; | |
2127 | } | |
2128 | } | |
2129 | #endif | |
2130 | /* mark it as used: */ | |
2131 | if (!mark_lock(curr, hlock, LOCK_USED, ip)) | |
2132 | return 0; | |
2133 | out_calc_hash: | |
2134 | /* | |
2135 | * Calculate the chain hash: it's the combined has of all the | |
2136 | * lock keys along the dependency chain. We save the hash value | |
2137 | * at every step so that we can get the current hash easily | |
2138 | * after unlock. The chain hash is then used to cache dependency | |
2139 | * results. | |
2140 | * | |
2141 | * The 'key ID' is what is the most compact key value to drive | |
2142 | * the hash, not class->key. | |
2143 | */ | |
2144 | id = class - lock_classes; | |
2145 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2146 | return 0; | |
2147 | ||
2148 | chain_key = curr->curr_chain_key; | |
2149 | if (!depth) { | |
2150 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2151 | return 0; | |
2152 | chain_head = 1; | |
2153 | } | |
2154 | ||
2155 | hlock->prev_chain_key = chain_key; | |
2156 | ||
2157 | #ifdef CONFIG_TRACE_IRQFLAGS | |
2158 | /* | |
2159 | * Keep track of points where we cross into an interrupt context: | |
2160 | */ | |
2161 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2162 | curr->softirq_context; | |
2163 | if (depth) { | |
2164 | struct held_lock *prev_hlock; | |
2165 | ||
2166 | prev_hlock = curr->held_locks + depth-1; | |
2167 | /* | |
2168 | * If we cross into another context, reset the | |
2169 | * hash key (this also prevents the checking and the | |
2170 | * adding of the dependency to 'prev'): | |
2171 | */ | |
2172 | if (prev_hlock->irq_context != hlock->irq_context) { | |
2173 | chain_key = 0; | |
2174 | chain_head = 1; | |
2175 | } | |
2176 | } | |
2177 | #endif | |
2178 | chain_key = iterate_chain_key(chain_key, id); | |
2179 | curr->curr_chain_key = chain_key; | |
2180 | ||
2181 | /* | |
2182 | * Trylock needs to maintain the stack of held locks, but it | |
2183 | * does not add new dependencies, because trylock can be done | |
2184 | * in any order. | |
2185 | * | |
2186 | * We look up the chain_key and do the O(N^2) check and update of | |
2187 | * the dependencies only if this is a new dependency chain. | |
2188 | * (If lookup_chain_cache() returns with 1 it acquires | |
74c383f1 | 2189 | * graph_lock for us) |
fbb9ce95 | 2190 | */ |
81fc685a | 2191 | if (!trylock && (check == 2) && lookup_chain_cache(chain_key, class)) { |
fbb9ce95 IM |
2192 | /* |
2193 | * Check whether last held lock: | |
2194 | * | |
2195 | * - is irq-safe, if this lock is irq-unsafe | |
2196 | * - is softirq-safe, if this lock is hardirq-unsafe | |
2197 | * | |
2198 | * And check whether the new lock's dependency graph | |
2199 | * could lead back to the previous lock. | |
2200 | * | |
2201 | * any of these scenarios could lead to a deadlock. If | |
2202 | * All validations | |
2203 | */ | |
2204 | int ret = check_deadlock(curr, hlock, lock, read); | |
2205 | ||
2206 | if (!ret) | |
2207 | return 0; | |
2208 | /* | |
2209 | * Mark recursive read, as we jump over it when | |
2210 | * building dependencies (just like we jump over | |
2211 | * trylock entries): | |
2212 | */ | |
2213 | if (ret == 2) | |
2214 | hlock->read = 2; | |
2215 | /* | |
2216 | * Add dependency only if this lock is not the head | |
2217 | * of the chain, and if it's not a secondary read-lock: | |
2218 | */ | |
2219 | if (!chain_head && ret != 2) | |
2220 | if (!check_prevs_add(curr, hlock)) | |
2221 | return 0; | |
74c383f1 | 2222 | graph_unlock(); |
381a2292 JP |
2223 | } else |
2224 | /* after lookup_chain_cache(): */ | |
2225 | if (unlikely(!debug_locks)) | |
2226 | return 0; | |
2227 | ||
fbb9ce95 IM |
2228 | curr->lockdep_depth++; |
2229 | check_chain_key(curr); | |
60e114d1 JP |
2230 | #ifdef CONFIG_DEBUG_LOCKDEP |
2231 | if (unlikely(!debug_locks)) | |
2232 | return 0; | |
2233 | #endif | |
fbb9ce95 IM |
2234 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2235 | debug_locks_off(); | |
2236 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2237 | printk("turning off the locking correctness validator.\n"); | |
2238 | return 0; | |
2239 | } | |
381a2292 | 2240 | |
fbb9ce95 IM |
2241 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2242 | max_lockdep_depth = curr->lockdep_depth; | |
2243 | ||
2244 | return 1; | |
2245 | } | |
2246 | ||
2247 | static int | |
2248 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2249 | unsigned long ip) | |
2250 | { | |
2251 | if (!debug_locks_off()) | |
2252 | return 0; | |
2253 | if (debug_locks_silent) | |
2254 | return 0; | |
2255 | ||
2256 | printk("\n=====================================\n"); | |
2257 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2258 | printk( "-------------------------------------\n"); | |
2259 | printk("%s/%d is trying to release lock (", | |
2260 | curr->comm, curr->pid); | |
2261 | print_lockdep_cache(lock); | |
2262 | printk(") at:\n"); | |
2263 | print_ip_sym(ip); | |
2264 | printk("but there are no more locks to release!\n"); | |
2265 | printk("\nother info that might help us debug this:\n"); | |
2266 | lockdep_print_held_locks(curr); | |
2267 | ||
2268 | printk("\nstack backtrace:\n"); | |
2269 | dump_stack(); | |
2270 | ||
2271 | return 0; | |
2272 | } | |
2273 | ||
2274 | /* | |
2275 | * Common debugging checks for both nested and non-nested unlock: | |
2276 | */ | |
2277 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2278 | unsigned long ip) | |
2279 | { | |
2280 | if (unlikely(!debug_locks)) | |
2281 | return 0; | |
2282 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2283 | return 0; | |
2284 | ||
2285 | if (curr->lockdep_depth <= 0) | |
2286 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2287 | ||
2288 | return 1; | |
2289 | } | |
2290 | ||
2291 | /* | |
2292 | * Remove the lock to the list of currently held locks in a | |
2293 | * potentially non-nested (out of order) manner. This is a | |
2294 | * relatively rare operation, as all the unlock APIs default | |
2295 | * to nested mode (which uses lock_release()): | |
2296 | */ | |
2297 | static int | |
2298 | lock_release_non_nested(struct task_struct *curr, | |
2299 | struct lockdep_map *lock, unsigned long ip) | |
2300 | { | |
2301 | struct held_lock *hlock, *prev_hlock; | |
2302 | unsigned int depth; | |
2303 | int i; | |
2304 | ||
2305 | /* | |
2306 | * Check whether the lock exists in the current stack | |
2307 | * of held locks: | |
2308 | */ | |
2309 | depth = curr->lockdep_depth; | |
2310 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2311 | return 0; | |
2312 | ||
2313 | prev_hlock = NULL; | |
2314 | for (i = depth-1; i >= 0; i--) { | |
2315 | hlock = curr->held_locks + i; | |
2316 | /* | |
2317 | * We must not cross into another context: | |
2318 | */ | |
2319 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2320 | break; | |
2321 | if (hlock->instance == lock) | |
2322 | goto found_it; | |
2323 | prev_hlock = hlock; | |
2324 | } | |
2325 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2326 | ||
2327 | found_it: | |
2328 | /* | |
2329 | * We have the right lock to unlock, 'hlock' points to it. | |
2330 | * Now we remove it from the stack, and add back the other | |
2331 | * entries (if any), recalculating the hash along the way: | |
2332 | */ | |
2333 | curr->lockdep_depth = i; | |
2334 | curr->curr_chain_key = hlock->prev_chain_key; | |
2335 | ||
2336 | for (i++; i < depth; i++) { | |
2337 | hlock = curr->held_locks + i; | |
2338 | if (!__lock_acquire(hlock->instance, | |
2339 | hlock->class->subclass, hlock->trylock, | |
2340 | hlock->read, hlock->check, hlock->hardirqs_off, | |
2341 | hlock->acquire_ip)) | |
2342 | return 0; | |
2343 | } | |
2344 | ||
2345 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2346 | return 0; | |
2347 | return 1; | |
2348 | } | |
2349 | ||
2350 | /* | |
2351 | * Remove the lock to the list of currently held locks - this gets | |
2352 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2353 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2354 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2355 | */ | |
2356 | static int lock_release_nested(struct task_struct *curr, | |
2357 | struct lockdep_map *lock, unsigned long ip) | |
2358 | { | |
2359 | struct held_lock *hlock; | |
2360 | unsigned int depth; | |
2361 | ||
2362 | /* | |
2363 | * Pop off the top of the lock stack: | |
2364 | */ | |
2365 | depth = curr->lockdep_depth - 1; | |
2366 | hlock = curr->held_locks + depth; | |
2367 | ||
2368 | /* | |
2369 | * Is the unlock non-nested: | |
2370 | */ | |
2371 | if (hlock->instance != lock) | |
2372 | return lock_release_non_nested(curr, lock, ip); | |
2373 | curr->lockdep_depth--; | |
2374 | ||
2375 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2376 | return 0; | |
2377 | ||
2378 | curr->curr_chain_key = hlock->prev_chain_key; | |
2379 | ||
2380 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2381 | hlock->prev_chain_key = 0; | |
2382 | hlock->class = NULL; | |
2383 | hlock->acquire_ip = 0; | |
2384 | hlock->irq_context = 0; | |
2385 | #endif | |
2386 | return 1; | |
2387 | } | |
2388 | ||
2389 | /* | |
2390 | * Remove the lock to the list of currently held locks - this gets | |
2391 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2392 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2393 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2394 | */ | |
2395 | static void | |
2396 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2397 | { | |
2398 | struct task_struct *curr = current; | |
2399 | ||
2400 | if (!check_unlock(curr, lock, ip)) | |
2401 | return; | |
2402 | ||
2403 | if (nested) { | |
2404 | if (!lock_release_nested(curr, lock, ip)) | |
2405 | return; | |
2406 | } else { | |
2407 | if (!lock_release_non_nested(curr, lock, ip)) | |
2408 | return; | |
2409 | } | |
2410 | ||
2411 | check_chain_key(curr); | |
2412 | } | |
2413 | ||
2414 | /* | |
2415 | * Check whether we follow the irq-flags state precisely: | |
2416 | */ | |
2417 | static void check_flags(unsigned long flags) | |
2418 | { | |
2419 | #if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS) | |
2420 | if (!debug_locks) | |
2421 | return; | |
2422 | ||
2423 | if (irqs_disabled_flags(flags)) | |
2424 | DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled); | |
2425 | else | |
2426 | DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled); | |
2427 | ||
2428 | /* | |
2429 | * We dont accurately track softirq state in e.g. | |
2430 | * hardirq contexts (such as on 4KSTACKS), so only | |
2431 | * check if not in hardirq contexts: | |
2432 | */ | |
2433 | if (!hardirq_count()) { | |
2434 | if (softirq_count()) | |
2435 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
2436 | else | |
2437 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
2438 | } | |
2439 | ||
2440 | if (!debug_locks) | |
2441 | print_irqtrace_events(current); | |
2442 | #endif | |
2443 | } | |
2444 | ||
2445 | /* | |
2446 | * We are not always called with irqs disabled - do that here, | |
2447 | * and also avoid lockdep recursion: | |
2448 | */ | |
2449 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2450 | int trylock, int read, int check, unsigned long ip) | |
2451 | { | |
2452 | unsigned long flags; | |
2453 | ||
2454 | if (unlikely(current->lockdep_recursion)) | |
2455 | return; | |
2456 | ||
2457 | raw_local_irq_save(flags); | |
2458 | check_flags(flags); | |
2459 | ||
2460 | current->lockdep_recursion = 1; | |
2461 | __lock_acquire(lock, subclass, trylock, read, check, | |
2462 | irqs_disabled_flags(flags), ip); | |
2463 | current->lockdep_recursion = 0; | |
2464 | raw_local_irq_restore(flags); | |
2465 | } | |
2466 | ||
2467 | EXPORT_SYMBOL_GPL(lock_acquire); | |
2468 | ||
2469 | void lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2470 | { | |
2471 | unsigned long flags; | |
2472 | ||
2473 | if (unlikely(current->lockdep_recursion)) | |
2474 | return; | |
2475 | ||
2476 | raw_local_irq_save(flags); | |
2477 | check_flags(flags); | |
2478 | current->lockdep_recursion = 1; | |
2479 | __lock_release(lock, nested, ip); | |
2480 | current->lockdep_recursion = 0; | |
2481 | raw_local_irq_restore(flags); | |
2482 | } | |
2483 | ||
2484 | EXPORT_SYMBOL_GPL(lock_release); | |
2485 | ||
2486 | /* | |
2487 | * Used by the testsuite, sanitize the validator state | |
2488 | * after a simulated failure: | |
2489 | */ | |
2490 | ||
2491 | void lockdep_reset(void) | |
2492 | { | |
2493 | unsigned long flags; | |
23d95a03 | 2494 | int i; |
fbb9ce95 IM |
2495 | |
2496 | raw_local_irq_save(flags); | |
2497 | current->curr_chain_key = 0; | |
2498 | current->lockdep_depth = 0; | |
2499 | current->lockdep_recursion = 0; | |
2500 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
2501 | nr_hardirq_chains = 0; | |
2502 | nr_softirq_chains = 0; | |
2503 | nr_process_chains = 0; | |
2504 | debug_locks = 1; | |
23d95a03 IM |
2505 | for (i = 0; i < CHAINHASH_SIZE; i++) |
2506 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
2507 | raw_local_irq_restore(flags); |
2508 | } | |
2509 | ||
2510 | static void zap_class(struct lock_class *class) | |
2511 | { | |
2512 | int i; | |
2513 | ||
2514 | /* | |
2515 | * Remove all dependencies this lock is | |
2516 | * involved in: | |
2517 | */ | |
2518 | for (i = 0; i < nr_list_entries; i++) { | |
2519 | if (list_entries[i].class == class) | |
2520 | list_del_rcu(&list_entries[i].entry); | |
2521 | } | |
2522 | /* | |
2523 | * Unhash the class and remove it from the all_lock_classes list: | |
2524 | */ | |
2525 | list_del_rcu(&class->hash_entry); | |
2526 | list_del_rcu(&class->lock_entry); | |
2527 | ||
2528 | } | |
2529 | ||
2530 | static inline int within(void *addr, void *start, unsigned long size) | |
2531 | { | |
2532 | return addr >= start && addr < start + size; | |
2533 | } | |
2534 | ||
2535 | void lockdep_free_key_range(void *start, unsigned long size) | |
2536 | { | |
2537 | struct lock_class *class, *next; | |
2538 | struct list_head *head; | |
2539 | unsigned long flags; | |
2540 | int i; | |
2541 | ||
2542 | raw_local_irq_save(flags); | |
74c383f1 | 2543 | graph_lock(); |
fbb9ce95 IM |
2544 | |
2545 | /* | |
2546 | * Unhash all classes that were created by this module: | |
2547 | */ | |
2548 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
2549 | head = classhash_table + i; | |
2550 | if (list_empty(head)) | |
2551 | continue; | |
2552 | list_for_each_entry_safe(class, next, head, hash_entry) | |
2553 | if (within(class->key, start, size)) | |
2554 | zap_class(class); | |
2555 | } | |
2556 | ||
74c383f1 | 2557 | graph_unlock(); |
fbb9ce95 IM |
2558 | raw_local_irq_restore(flags); |
2559 | } | |
2560 | ||
2561 | void lockdep_reset_lock(struct lockdep_map *lock) | |
2562 | { | |
d6d897ce | 2563 | struct lock_class *class, *next; |
fbb9ce95 IM |
2564 | struct list_head *head; |
2565 | unsigned long flags; | |
2566 | int i, j; | |
2567 | ||
2568 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
2569 | |
2570 | /* | |
d6d897ce IM |
2571 | * Remove all classes this lock might have: |
2572 | */ | |
2573 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
2574 | /* | |
2575 | * If the class exists we look it up and zap it: | |
2576 | */ | |
2577 | class = look_up_lock_class(lock, j); | |
2578 | if (class) | |
2579 | zap_class(class); | |
2580 | } | |
2581 | /* | |
2582 | * Debug check: in the end all mapped classes should | |
2583 | * be gone. | |
fbb9ce95 | 2584 | */ |
74c383f1 | 2585 | graph_lock(); |
fbb9ce95 IM |
2586 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
2587 | head = classhash_table + i; | |
2588 | if (list_empty(head)) | |
2589 | continue; | |
2590 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 2591 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
2592 | if (debug_locks_off_graph_unlock()) |
2593 | WARN_ON(1); | |
d6d897ce | 2594 | goto out_restore; |
fbb9ce95 IM |
2595 | } |
2596 | } | |
2597 | } | |
74c383f1 | 2598 | graph_unlock(); |
d6d897ce IM |
2599 | |
2600 | out_restore: | |
fbb9ce95 IM |
2601 | raw_local_irq_restore(flags); |
2602 | } | |
2603 | ||
1499993c | 2604 | void lockdep_init(void) |
fbb9ce95 IM |
2605 | { |
2606 | int i; | |
2607 | ||
2608 | /* | |
2609 | * Some architectures have their own start_kernel() | |
2610 | * code which calls lockdep_init(), while we also | |
2611 | * call lockdep_init() from the start_kernel() itself, | |
2612 | * and we want to initialize the hashes only once: | |
2613 | */ | |
2614 | if (lockdep_initialized) | |
2615 | return; | |
2616 | ||
2617 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
2618 | INIT_LIST_HEAD(classhash_table + i); | |
2619 | ||
2620 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
2621 | INIT_LIST_HEAD(chainhash_table + i); | |
2622 | ||
2623 | lockdep_initialized = 1; | |
2624 | } | |
2625 | ||
2626 | void __init lockdep_info(void) | |
2627 | { | |
2628 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
2629 | ||
2630 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); | |
2631 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); | |
2632 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
2633 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); | |
2634 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); | |
2635 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
2636 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
2637 | ||
2638 | printk(" memory used by lock dependency info: %lu kB\n", | |
2639 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
2640 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
2641 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
2642 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
2643 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
2644 | ||
2645 | printk(" per task-struct memory footprint: %lu bytes\n", | |
2646 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
2647 | ||
2648 | #ifdef CONFIG_DEBUG_LOCKDEP | |
2649 | if (lockdep_init_error) | |
2650 | printk("WARNING: lockdep init error! Arch code didnt call lockdep_init() early enough?\n"); | |
2651 | #endif | |
2652 | } | |
2653 | ||
2654 | static inline int in_range(const void *start, const void *addr, const void *end) | |
2655 | { | |
2656 | return addr >= start && addr <= end; | |
2657 | } | |
2658 | ||
2659 | static void | |
2660 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 2661 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
2662 | { |
2663 | if (!debug_locks_off()) | |
2664 | return; | |
2665 | if (debug_locks_silent) | |
2666 | return; | |
2667 | ||
2668 | printk("\n=========================\n"); | |
2669 | printk( "[ BUG: held lock freed! ]\n"); | |
2670 | printk( "-------------------------\n"); | |
2671 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
2672 | curr->comm, curr->pid, mem_from, mem_to-1); | |
55794a41 | 2673 | print_lock(hlock); |
fbb9ce95 IM |
2674 | lockdep_print_held_locks(curr); |
2675 | ||
2676 | printk("\nstack backtrace:\n"); | |
2677 | dump_stack(); | |
2678 | } | |
2679 | ||
2680 | /* | |
2681 | * Called when kernel memory is freed (or unmapped), or if a lock | |
2682 | * is destroyed or reinitialized - this code checks whether there is | |
2683 | * any held lock in the memory range of <from> to <to>: | |
2684 | */ | |
2685 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
2686 | { | |
2687 | const void *mem_to = mem_from + mem_len, *lock_from, *lock_to; | |
2688 | struct task_struct *curr = current; | |
2689 | struct held_lock *hlock; | |
2690 | unsigned long flags; | |
2691 | int i; | |
2692 | ||
2693 | if (unlikely(!debug_locks)) | |
2694 | return; | |
2695 | ||
2696 | local_irq_save(flags); | |
2697 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2698 | hlock = curr->held_locks + i; | |
2699 | ||
2700 | lock_from = (void *)hlock->instance; | |
2701 | lock_to = (void *)(hlock->instance + 1); | |
2702 | ||
2703 | if (!in_range(mem_from, lock_from, mem_to) && | |
2704 | !in_range(mem_from, lock_to, mem_to)) | |
2705 | continue; | |
2706 | ||
55794a41 | 2707 | print_freed_lock_bug(curr, mem_from, mem_to, hlock); |
fbb9ce95 IM |
2708 | break; |
2709 | } | |
2710 | local_irq_restore(flags); | |
2711 | } | |
ed07536e | 2712 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
2713 | |
2714 | static void print_held_locks_bug(struct task_struct *curr) | |
2715 | { | |
2716 | if (!debug_locks_off()) | |
2717 | return; | |
2718 | if (debug_locks_silent) | |
2719 | return; | |
2720 | ||
2721 | printk("\n=====================================\n"); | |
2722 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
2723 | printk( "-------------------------------------\n"); | |
2724 | printk("%s/%d is exiting with locks still held!\n", | |
2725 | curr->comm, curr->pid); | |
2726 | lockdep_print_held_locks(curr); | |
2727 | ||
2728 | printk("\nstack backtrace:\n"); | |
2729 | dump_stack(); | |
2730 | } | |
2731 | ||
2732 | void debug_check_no_locks_held(struct task_struct *task) | |
2733 | { | |
2734 | if (unlikely(task->lockdep_depth > 0)) | |
2735 | print_held_locks_bug(task); | |
2736 | } | |
2737 | ||
2738 | void debug_show_all_locks(void) | |
2739 | { | |
2740 | struct task_struct *g, *p; | |
2741 | int count = 10; | |
2742 | int unlock = 1; | |
2743 | ||
9c35dd7f JP |
2744 | if (unlikely(!debug_locks)) { |
2745 | printk("INFO: lockdep is turned off.\n"); | |
2746 | return; | |
2747 | } | |
fbb9ce95 IM |
2748 | printk("\nShowing all locks held in the system:\n"); |
2749 | ||
2750 | /* | |
2751 | * Here we try to get the tasklist_lock as hard as possible, | |
2752 | * if not successful after 2 seconds we ignore it (but keep | |
2753 | * trying). This is to enable a debug printout even if a | |
2754 | * tasklist_lock-holding task deadlocks or crashes. | |
2755 | */ | |
2756 | retry: | |
2757 | if (!read_trylock(&tasklist_lock)) { | |
2758 | if (count == 10) | |
2759 | printk("hm, tasklist_lock locked, retrying... "); | |
2760 | if (count) { | |
2761 | count--; | |
2762 | printk(" #%d", 10-count); | |
2763 | mdelay(200); | |
2764 | goto retry; | |
2765 | } | |
2766 | printk(" ignoring it.\n"); | |
2767 | unlock = 0; | |
2768 | } | |
2769 | if (count != 10) | |
2770 | printk(" locked it.\n"); | |
2771 | ||
2772 | do_each_thread(g, p) { | |
2773 | if (p->lockdep_depth) | |
2774 | lockdep_print_held_locks(p); | |
2775 | if (!unlock) | |
2776 | if (read_trylock(&tasklist_lock)) | |
2777 | unlock = 1; | |
2778 | } while_each_thread(g, p); | |
2779 | ||
2780 | printk("\n"); | |
2781 | printk("=============================================\n\n"); | |
2782 | ||
2783 | if (unlock) | |
2784 | read_unlock(&tasklist_lock); | |
2785 | } | |
2786 | ||
2787 | EXPORT_SYMBOL_GPL(debug_show_all_locks); | |
2788 | ||
2789 | void debug_show_held_locks(struct task_struct *task) | |
2790 | { | |
9c35dd7f JP |
2791 | if (unlikely(!debug_locks)) { |
2792 | printk("INFO: lockdep is turned off.\n"); | |
2793 | return; | |
2794 | } | |
fbb9ce95 IM |
2795 | lockdep_print_held_locks(task); |
2796 | } | |
2797 | ||
2798 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |