744da6265d99f2289d61e267f44e6983a420d8e6
[linux-2.6.git] / kernel / lockdep.c
1 /*
2  * kernel/lockdep.c
3  *
4  * Runtime locking correctness validator
5  *
6  * Started by Ingo Molnar:
7  *
8  *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
10  *
11  * this code maps all the lock dependencies as they occur in a live kernel
12  * and will warn about the following classes of locking bugs:
13  *
14  * - lock inversion scenarios
15  * - circular lock dependencies
16  * - hardirq/softirq safe/unsafe locking bugs
17  *
18  * Bugs are reported even if the current locking scenario does not cause
19  * any deadlock at this point.
20  *
21  * I.e. if anytime in the past two locks were taken in a different order,
22  * even if it happened for another task, even if those were different
23  * locks (but of the same class as this lock), this code will detect it.
24  *
25  * Thanks to Arjan van de Ven for coming up with the initial idea of
26  * mapping lock dependencies runtime.
27  */
28 #define DISABLE_BRANCH_PROFILING
29 #include <linux/mutex.h>
30 #include <linux/sched.h>
31 #include <linux/delay.h>
32 #include <linux/module.h>
33 #include <linux/proc_fs.h>
34 #include <linux/seq_file.h>
35 #include <linux/spinlock.h>
36 #include <linux/kallsyms.h>
37 #include <linux/interrupt.h>
38 #include <linux/stacktrace.h>
39 #include <linux/debug_locks.h>
40 #include <linux/irqflags.h>
41 #include <linux/utsname.h>
42 #include <linux/hash.h>
43 #include <linux/ftrace.h>
44 #include <linux/stringify.h>
45 #include <linux/bitops.h>
46 #include <asm/sections.h>
47
48 #include "lockdep_internals.h"
49
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/lockdep.h>
52
53 #ifdef CONFIG_PROVE_LOCKING
54 int prove_locking = 1;
55 module_param(prove_locking, int, 0644);
56 #else
57 #define prove_locking 0
58 #endif
59
60 #ifdef CONFIG_LOCK_STAT
61 int lock_stat = 1;
62 module_param(lock_stat, int, 0644);
63 #else
64 #define lock_stat 0
65 #endif
66
67 /*
68  * lockdep_lock: protects the lockdep graph, the hashes and the
69  *               class/list/hash allocators.
70  *
71  * This is one of the rare exceptions where it's justified
72  * to use a raw spinlock - we really dont want the spinlock
73  * code to recurse back into the lockdep code...
74  */
75 static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
76
77 static int graph_lock(void)
78 {
79         __raw_spin_lock(&lockdep_lock);
80         /*
81          * Make sure that if another CPU detected a bug while
82          * walking the graph we dont change it (while the other
83          * CPU is busy printing out stuff with the graph lock
84          * dropped already)
85          */
86         if (!debug_locks) {
87                 __raw_spin_unlock(&lockdep_lock);
88                 return 0;
89         }
90         /* prevent any recursions within lockdep from causing deadlocks */
91         current->lockdep_recursion++;
92         return 1;
93 }
94
95 static inline int graph_unlock(void)
96 {
97         if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
98                 return DEBUG_LOCKS_WARN_ON(1);
99
100         current->lockdep_recursion--;
101         __raw_spin_unlock(&lockdep_lock);
102         return 0;
103 }
104
105 /*
106  * Turn lock debugging off and return with 0 if it was off already,
107  * and also release the graph lock:
108  */
109 static inline int debug_locks_off_graph_unlock(void)
110 {
111         int ret = debug_locks_off();
112
113         __raw_spin_unlock(&lockdep_lock);
114
115         return ret;
116 }
117
118 static int lockdep_initialized;
119
120 unsigned long nr_list_entries;
121 struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
122
123 /*
124  * All data structures here are protected by the global debug_lock.
125  *
126  * Mutex key structs only get allocated, once during bootup, and never
127  * get freed - this significantly simplifies the debugging code.
128  */
129 unsigned long nr_lock_classes;
130 static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
131
132 static inline struct lock_class *hlock_class(struct held_lock *hlock)
133 {
134         if (!hlock->class_idx) {
135                 DEBUG_LOCKS_WARN_ON(1);
136                 return NULL;
137         }
138         return lock_classes + hlock->class_idx - 1;
139 }
140
141 #ifdef CONFIG_LOCK_STAT
142 static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
143
144 static int lock_point(unsigned long points[], unsigned long ip)
145 {
146         int i;
147
148         for (i = 0; i < LOCKSTAT_POINTS; i++) {
149                 if (points[i] == 0) {
150                         points[i] = ip;
151                         break;
152                 }
153                 if (points[i] == ip)
154                         break;
155         }
156
157         return i;
158 }
159
160 static void lock_time_inc(struct lock_time *lt, s64 time)
161 {
162         if (time > lt->max)
163                 lt->max = time;
164
165         if (time < lt->min || !lt->min)
166                 lt->min = time;
167
168         lt->total += time;
169         lt->nr++;
170 }
171
172 static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
173 {
174         dst->min += src->min;
175         dst->max += src->max;
176         dst->total += src->total;
177         dst->nr += src->nr;
178 }
179
180 struct lock_class_stats lock_stats(struct lock_class *class)
181 {
182         struct lock_class_stats stats;
183         int cpu, i;
184
185         memset(&stats, 0, sizeof(struct lock_class_stats));
186         for_each_possible_cpu(cpu) {
187                 struct lock_class_stats *pcs =
188                         &per_cpu(lock_stats, cpu)[class - lock_classes];
189
190                 for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
191                         stats.contention_point[i] += pcs->contention_point[i];
192
193                 for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
194                         stats.contending_point[i] += pcs->contending_point[i];
195
196                 lock_time_add(&pcs->read_waittime, &stats.read_waittime);
197                 lock_time_add(&pcs->write_waittime, &stats.write_waittime);
198
199                 lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
200                 lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
201
202                 for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
203                         stats.bounces[i] += pcs->bounces[i];
204         }
205
206         return stats;
207 }
208
209 void clear_lock_stats(struct lock_class *class)
210 {
211         int cpu;
212
213         for_each_possible_cpu(cpu) {
214                 struct lock_class_stats *cpu_stats =
215                         &per_cpu(lock_stats, cpu)[class - lock_classes];
216
217                 memset(cpu_stats, 0, sizeof(struct lock_class_stats));
218         }
219         memset(class->contention_point, 0, sizeof(class->contention_point));
220         memset(class->contending_point, 0, sizeof(class->contending_point));
221 }
222
223 static struct lock_class_stats *get_lock_stats(struct lock_class *class)
224 {
225         return &get_cpu_var(lock_stats)[class - lock_classes];
226 }
227
228 static void put_lock_stats(struct lock_class_stats *stats)
229 {
230         put_cpu_var(lock_stats);
231 }
232
233 static void lock_release_holdtime(struct held_lock *hlock)
234 {
235         struct lock_class_stats *stats;
236         s64 holdtime;
237
238         if (!lock_stat)
239                 return;
240
241         holdtime = sched_clock() - hlock->holdtime_stamp;
242
243         stats = get_lock_stats(hlock_class(hlock));
244         if (hlock->read)
245                 lock_time_inc(&stats->read_holdtime, holdtime);
246         else
247                 lock_time_inc(&stats->write_holdtime, holdtime);
248         put_lock_stats(stats);
249 }
250 #else
251 static inline void lock_release_holdtime(struct held_lock *hlock)
252 {
253 }
254 #endif
255
256 /*
257  * We keep a global list of all lock classes. The list only grows,
258  * never shrinks. The list is only accessed with the lockdep
259  * spinlock lock held.
260  */
261 LIST_HEAD(all_lock_classes);
262
263 /*
264  * The lockdep classes are in a hash-table as well, for fast lookup:
265  */
266 #define CLASSHASH_BITS          (MAX_LOCKDEP_KEYS_BITS - 1)
267 #define CLASSHASH_SIZE          (1UL << CLASSHASH_BITS)
268 #define __classhashfn(key)      hash_long((unsigned long)key, CLASSHASH_BITS)
269 #define classhashentry(key)     (classhash_table + __classhashfn((key)))
270
271 static struct list_head classhash_table[CLASSHASH_SIZE];
272
273 /*
274  * We put the lock dependency chains into a hash-table as well, to cache
275  * their existence:
276  */
277 #define CHAINHASH_BITS          (MAX_LOCKDEP_CHAINS_BITS-1)
278 #define CHAINHASH_SIZE          (1UL << CHAINHASH_BITS)
279 #define __chainhashfn(chain)    hash_long(chain, CHAINHASH_BITS)
280 #define chainhashentry(chain)   (chainhash_table + __chainhashfn((chain)))
281
282 static struct list_head chainhash_table[CHAINHASH_SIZE];
283
284 /*
285  * The hash key of the lock dependency chains is a hash itself too:
286  * it's a hash of all locks taken up to that lock, including that lock.
287  * It's a 64-bit hash, because it's important for the keys to be
288  * unique.
289  */
290 #define iterate_chain_key(key1, key2) \
291         (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
292         ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
293         (key2))
294
295 void lockdep_off(void)
296 {
297         current->lockdep_recursion++;
298 }
299 EXPORT_SYMBOL(lockdep_off);
300
301 void lockdep_on(void)
302 {
303         current->lockdep_recursion--;
304 }
305 EXPORT_SYMBOL(lockdep_on);
306
307 /*
308  * Debugging switches:
309  */
310
311 #define VERBOSE                 0
312 #define VERY_VERBOSE            0
313
314 #if VERBOSE
315 # define HARDIRQ_VERBOSE        1
316 # define SOFTIRQ_VERBOSE        1
317 # define RECLAIM_VERBOSE        1
318 #else
319 # define HARDIRQ_VERBOSE        0
320 # define SOFTIRQ_VERBOSE        0
321 # define RECLAIM_VERBOSE        0
322 #endif
323
324 #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
325 /*
326  * Quick filtering for interesting events:
327  */
328 static int class_filter(struct lock_class *class)
329 {
330 #if 0
331         /* Example */
332         if (class->name_version == 1 &&
333                         !strcmp(class->name, "lockname"))
334                 return 1;
335         if (class->name_version == 1 &&
336                         !strcmp(class->name, "&struct->lockfield"))
337                 return 1;
338 #endif
339         /* Filter everything else. 1 would be to allow everything else */
340         return 0;
341 }
342 #endif
343
344 static int verbose(struct lock_class *class)
345 {
346 #if VERBOSE
347         return class_filter(class);
348 #endif
349         return 0;
350 }
351
352 /*
353  * Stack-trace: tightly packed array of stack backtrace
354  * addresses. Protected by the graph_lock.
355  */
356 unsigned long nr_stack_trace_entries;
357 static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
358
359 static int save_trace(struct stack_trace *trace)
360 {
361         trace->nr_entries = 0;
362         trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
363         trace->entries = stack_trace + nr_stack_trace_entries;
364
365         trace->skip = 3;
366
367         save_stack_trace(trace);
368
369         trace->max_entries = trace->nr_entries;
370
371         nr_stack_trace_entries += trace->nr_entries;
372
373         if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
374                 if (!debug_locks_off_graph_unlock())
375                         return 0;
376
377                 printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
378                 printk("turning off the locking correctness validator.\n");
379                 dump_stack();
380
381                 return 0;
382         }
383
384         return 1;
385 }
386
387 unsigned int nr_hardirq_chains;
388 unsigned int nr_softirq_chains;
389 unsigned int nr_process_chains;
390 unsigned int max_lockdep_depth;
391 unsigned int max_recursion_depth;
392
393 static unsigned int lockdep_dependency_gen_id;
394
395 static bool lockdep_dependency_visit(struct lock_class *source,
396                                      unsigned int depth)
397 {
398         if (!depth)
399                 lockdep_dependency_gen_id++;
400         if (source->dep_gen_id == lockdep_dependency_gen_id)
401                 return true;
402         source->dep_gen_id = lockdep_dependency_gen_id;
403         return false;
404 }
405
406 #ifdef CONFIG_DEBUG_LOCKDEP
407 /*
408  * We cannot printk in early bootup code. Not even early_printk()
409  * might work. So we mark any initialization errors and printk
410  * about it later on, in lockdep_info().
411  */
412 static int lockdep_init_error;
413 static unsigned long lockdep_init_trace_data[20];
414 static struct stack_trace lockdep_init_trace = {
415         .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
416         .entries = lockdep_init_trace_data,
417 };
418
419 /*
420  * Various lockdep statistics:
421  */
422 atomic_t chain_lookup_hits;
423 atomic_t chain_lookup_misses;
424 atomic_t hardirqs_on_events;
425 atomic_t hardirqs_off_events;
426 atomic_t redundant_hardirqs_on;
427 atomic_t redundant_hardirqs_off;
428 atomic_t softirqs_on_events;
429 atomic_t softirqs_off_events;
430 atomic_t redundant_softirqs_on;
431 atomic_t redundant_softirqs_off;
432 atomic_t nr_unused_locks;
433 atomic_t nr_cyclic_checks;
434 atomic_t nr_cyclic_check_recursions;
435 atomic_t nr_find_usage_forwards_checks;
436 atomic_t nr_find_usage_forwards_recursions;
437 atomic_t nr_find_usage_backwards_checks;
438 atomic_t nr_find_usage_backwards_recursions;
439 #endif
440
441 /*
442  * Locking printouts:
443  */
444
445 #define __USAGE(__STATE)                                                \
446         [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W",       \
447         [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W",         \
448         [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
449         [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
450
451 static const char *usage_str[] =
452 {
453 #define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
454 #include "lockdep_states.h"
455 #undef LOCKDEP_STATE
456         [LOCK_USED] = "INITIAL USE",
457 };
458
459 const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
460 {
461         return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
462 }
463
464 static inline unsigned long lock_flag(enum lock_usage_bit bit)
465 {
466         return 1UL << bit;
467 }
468
469 static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
470 {
471         char c = '.';
472
473         if (class->usage_mask & lock_flag(bit + 2))
474                 c = '+';
475         if (class->usage_mask & lock_flag(bit)) {
476                 c = '-';
477                 if (class->usage_mask & lock_flag(bit + 2))
478                         c = '?';
479         }
480
481         return c;
482 }
483
484 void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
485 {
486         int i = 0;
487
488 #define LOCKDEP_STATE(__STATE)                                          \
489         usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE);     \
490         usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
491 #include "lockdep_states.h"
492 #undef LOCKDEP_STATE
493
494         usage[i] = '\0';
495 }
496
497 static void print_lock_name(struct lock_class *class)
498 {
499         char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS];
500         const char *name;
501
502         get_usage_chars(class, usage);
503
504         name = class->name;
505         if (!name) {
506                 name = __get_key_name(class->key, str);
507                 printk(" (%s", name);
508         } else {
509                 printk(" (%s", name);
510                 if (class->name_version > 1)
511                         printk("#%d", class->name_version);
512                 if (class->subclass)
513                         printk("/%d", class->subclass);
514         }
515         printk("){%s}", usage);
516 }
517
518 static void print_lockdep_cache(struct lockdep_map *lock)
519 {
520         const char *name;
521         char str[KSYM_NAME_LEN];
522
523         name = lock->name;
524         if (!name)
525                 name = __get_key_name(lock->key->subkeys, str);
526
527         printk("%s", name);
528 }
529
530 static void print_lock(struct held_lock *hlock)
531 {
532         print_lock_name(hlock_class(hlock));
533         printk(", at: ");
534         print_ip_sym(hlock->acquire_ip);
535 }
536
537 static void lockdep_print_held_locks(struct task_struct *curr)
538 {
539         int i, depth = curr->lockdep_depth;
540
541         if (!depth) {
542                 printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
543                 return;
544         }
545         printk("%d lock%s held by %s/%d:\n",
546                 depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
547
548         for (i = 0; i < depth; i++) {
549                 printk(" #%d: ", i);
550                 print_lock(curr->held_locks + i);
551         }
552 }
553
554 static void print_lock_class_header(struct lock_class *class, int depth)
555 {
556         int bit;
557
558         printk("%*s->", depth, "");
559         print_lock_name(class);
560         printk(" ops: %lu", class->ops);
561         printk(" {\n");
562
563         for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
564                 if (class->usage_mask & (1 << bit)) {
565                         int len = depth;
566
567                         len += printk("%*s   %s", depth, "", usage_str[bit]);
568                         len += printk(" at:\n");
569                         print_stack_trace(class->usage_traces + bit, len);
570                 }
571         }
572         printk("%*s }\n", depth, "");
573
574         printk("%*s ... key      at: ",depth,"");
575         print_ip_sym((unsigned long)class->key);
576 }
577
578 /*
579  * printk the shortest lock dependencies from @start to @end in reverse order:
580  */
581 static void __used
582 print_shortest_lock_dependencies(struct lock_list *leaf,
583                                 struct lock_list *root)
584 {
585         struct lock_list *entry = leaf;
586         int depth;
587
588         /*compute depth from generated tree by BFS*/
589         depth = get_lock_depth(leaf);
590
591         do {
592                 print_lock_class_header(entry->class, depth);
593                 printk("%*s ... acquired at:\n", depth, "");
594                 print_stack_trace(&entry->trace, 2);
595                 printk("\n");
596
597                 if (depth == 0 && (entry != root)) {
598                         printk("lockdep:%s bad BFS generated tree\n", __func__);
599                         break;
600                 }
601
602                 entry = get_lock_parent(entry);
603                 depth--;
604         } while (entry && (depth >= 0));
605
606         return;
607 }
608 /*
609  * printk all lock dependencies starting at <entry>:
610  */
611 static void __used
612 print_lock_dependencies(struct lock_class *class, int depth)
613 {
614         struct lock_list *entry;
615
616         if (lockdep_dependency_visit(class, depth))
617                 return;
618
619         if (DEBUG_LOCKS_WARN_ON(depth >= 20))
620                 return;
621
622         print_lock_class_header(class, depth);
623
624         list_for_each_entry(entry, &class->locks_after, entry) {
625                 if (DEBUG_LOCKS_WARN_ON(!entry->class))
626                         return;
627
628                 print_lock_dependencies(entry->class, depth + 1);
629
630                 printk("%*s ... acquired at:\n",depth,"");
631                 print_stack_trace(&entry->trace, 2);
632                 printk("\n");
633         }
634 }
635
636 static void print_kernel_version(void)
637 {
638         printk("%s %.*s\n", init_utsname()->release,
639                 (int)strcspn(init_utsname()->version, " "),
640                 init_utsname()->version);
641 }
642
643 static int very_verbose(struct lock_class *class)
644 {
645 #if VERY_VERBOSE
646         return class_filter(class);
647 #endif
648         return 0;
649 }
650
651 /*
652  * Is this the address of a static object:
653  */
654 static int static_obj(void *obj)
655 {
656         unsigned long start = (unsigned long) &_stext,
657                       end   = (unsigned long) &_end,
658                       addr  = (unsigned long) obj;
659 #ifdef CONFIG_SMP
660         int i;
661 #endif
662
663         /*
664          * static variable?
665          */
666         if ((addr >= start) && (addr < end))
667                 return 1;
668
669 #ifdef CONFIG_SMP
670         /*
671          * percpu var?
672          */
673         for_each_possible_cpu(i) {
674                 start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
675                 end   = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
676                                         + per_cpu_offset(i);
677
678                 if ((addr >= start) && (addr < end))
679                         return 1;
680         }
681 #endif
682
683         /*
684          * module var?
685          */
686         return is_module_address(addr);
687 }
688
689 /*
690  * To make lock name printouts unique, we calculate a unique
691  * class->name_version generation counter:
692  */
693 static int count_matching_names(struct lock_class *new_class)
694 {
695         struct lock_class *class;
696         int count = 0;
697
698         if (!new_class->name)
699                 return 0;
700
701         list_for_each_entry(class, &all_lock_classes, lock_entry) {
702                 if (new_class->key - new_class->subclass == class->key)
703                         return class->name_version;
704                 if (class->name && !strcmp(class->name, new_class->name))
705                         count = max(count, class->name_version);
706         }
707
708         return count + 1;
709 }
710
711 /*
712  * Register a lock's class in the hash-table, if the class is not present
713  * yet. Otherwise we look it up. We cache the result in the lock object
714  * itself, so actual lookup of the hash should be once per lock object.
715  */
716 static inline struct lock_class *
717 look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
718 {
719         struct lockdep_subclass_key *key;
720         struct list_head *hash_head;
721         struct lock_class *class;
722
723 #ifdef CONFIG_DEBUG_LOCKDEP
724         /*
725          * If the architecture calls into lockdep before initializing
726          * the hashes then we'll warn about it later. (we cannot printk
727          * right now)
728          */
729         if (unlikely(!lockdep_initialized)) {
730                 lockdep_init();
731                 lockdep_init_error = 1;
732                 save_stack_trace(&lockdep_init_trace);
733         }
734 #endif
735
736         /*
737          * Static locks do not have their class-keys yet - for them the key
738          * is the lock object itself:
739          */
740         if (unlikely(!lock->key))
741                 lock->key = (void *)lock;
742
743         /*
744          * NOTE: the class-key must be unique. For dynamic locks, a static
745          * lock_class_key variable is passed in through the mutex_init()
746          * (or spin_lock_init()) call - which acts as the key. For static
747          * locks we use the lock object itself as the key.
748          */
749         BUILD_BUG_ON(sizeof(struct lock_class_key) >
750                         sizeof(struct lockdep_map));
751
752         key = lock->key->subkeys + subclass;
753
754         hash_head = classhashentry(key);
755
756         /*
757          * We can walk the hash lockfree, because the hash only
758          * grows, and we are careful when adding entries to the end:
759          */
760         list_for_each_entry(class, hash_head, hash_entry) {
761                 if (class->key == key) {
762                         WARN_ON_ONCE(class->name != lock->name);
763                         return class;
764                 }
765         }
766
767         return NULL;
768 }
769
770 /*
771  * Register a lock's class in the hash-table, if the class is not present
772  * yet. Otherwise we look it up. We cache the result in the lock object
773  * itself, so actual lookup of the hash should be once per lock object.
774  */
775 static inline struct lock_class *
776 register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
777 {
778         struct lockdep_subclass_key *key;
779         struct list_head *hash_head;
780         struct lock_class *class;
781         unsigned long flags;
782
783         class = look_up_lock_class(lock, subclass);
784         if (likely(class))
785                 return class;
786
787         /*
788          * Debug-check: all keys must be persistent!
789          */
790         if (!static_obj(lock->key)) {
791                 debug_locks_off();
792                 printk("INFO: trying to register non-static key.\n");
793                 printk("the code is fine but needs lockdep annotation.\n");
794                 printk("turning off the locking correctness validator.\n");
795                 dump_stack();
796
797                 return NULL;
798         }
799
800         key = lock->key->subkeys + subclass;
801         hash_head = classhashentry(key);
802
803         raw_local_irq_save(flags);
804         if (!graph_lock()) {
805                 raw_local_irq_restore(flags);
806                 return NULL;
807         }
808         /*
809          * We have to do the hash-walk again, to avoid races
810          * with another CPU:
811          */
812         list_for_each_entry(class, hash_head, hash_entry)
813                 if (class->key == key)
814                         goto out_unlock_set;
815         /*
816          * Allocate a new key from the static array, and add it to
817          * the hash:
818          */
819         if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
820                 if (!debug_locks_off_graph_unlock()) {
821                         raw_local_irq_restore(flags);
822                         return NULL;
823                 }
824                 raw_local_irq_restore(flags);
825
826                 printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
827                 printk("turning off the locking correctness validator.\n");
828                 dump_stack();
829                 return NULL;
830         }
831         class = lock_classes + nr_lock_classes++;
832         debug_atomic_inc(&nr_unused_locks);
833         class->key = key;
834         class->name = lock->name;
835         class->subclass = subclass;
836         INIT_LIST_HEAD(&class->lock_entry);
837         INIT_LIST_HEAD(&class->locks_before);
838         INIT_LIST_HEAD(&class->locks_after);
839         class->name_version = count_matching_names(class);
840         /*
841          * We use RCU's safe list-add method to make
842          * parallel walking of the hash-list safe:
843          */
844         list_add_tail_rcu(&class->hash_entry, hash_head);
845         /*
846          * Add it to the global list of classes:
847          */
848         list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
849
850         if (verbose(class)) {
851                 graph_unlock();
852                 raw_local_irq_restore(flags);
853
854                 printk("\nnew class %p: %s", class->key, class->name);
855                 if (class->name_version > 1)
856                         printk("#%d", class->name_version);
857                 printk("\n");
858                 dump_stack();
859
860                 raw_local_irq_save(flags);
861                 if (!graph_lock()) {
862                         raw_local_irq_restore(flags);
863                         return NULL;
864                 }
865         }
866 out_unlock_set:
867         graph_unlock();
868         raw_local_irq_restore(flags);
869
870         if (!subclass || force)
871                 lock->class_cache = class;
872
873         if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
874                 return NULL;
875
876         return class;
877 }
878
879 #ifdef CONFIG_PROVE_LOCKING
880 /*
881  * Allocate a lockdep entry. (assumes the graph_lock held, returns
882  * with NULL on failure)
883  */
884 static struct lock_list *alloc_list_entry(void)
885 {
886         if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
887                 if (!debug_locks_off_graph_unlock())
888                         return NULL;
889
890                 printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
891                 printk("turning off the locking correctness validator.\n");
892                 dump_stack();
893                 return NULL;
894         }
895         return list_entries + nr_list_entries++;
896 }
897
898 /*
899  * Add a new dependency to the head of the list:
900  */
901 static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
902                             struct list_head *head, unsigned long ip, int distance)
903 {
904         struct lock_list *entry;
905         /*
906          * Lock not present yet - get a new dependency struct and
907          * add it to the list:
908          */
909         entry = alloc_list_entry();
910         if (!entry)
911                 return 0;
912
913         if (!save_trace(&entry->trace))
914                 return 0;
915
916         entry->class = this;
917         entry->distance = distance;
918         /*
919          * Since we never remove from the dependency list, the list can
920          * be walked lockless by other CPUs, it's only allocation
921          * that must be protected by the spinlock. But this also means
922          * we must make new entries visible only once writes to the
923          * entry become visible - hence the RCU op:
924          */
925         list_add_tail_rcu(&entry->entry, head);
926
927         return 1;
928 }
929
930 unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)];
931 static struct circular_queue  lock_cq;
932 unsigned int max_bfs_queue_depth;
933 static int __bfs(struct lock_list *source_entry,
934                         void *data,
935                         int (*match)(struct lock_list *entry, void *data),
936                         struct lock_list **target_entry,
937                         int forward)
938 {
939         struct lock_list *entry;
940         struct list_head *head;
941         struct circular_queue *cq = &lock_cq;
942         int ret = 1;
943
944         if (match(source_entry, data)) {
945                 *target_entry = source_entry;
946                 ret = 0;
947                 goto exit;
948         }
949
950         if (forward)
951                 head = &source_entry->class->locks_after;
952         else
953                 head = &source_entry->class->locks_before;
954
955         if (list_empty(head))
956                 goto exit;
957
958         __cq_init(cq);
959         __cq_enqueue(cq, (unsigned long)source_entry);
960
961         while (!__cq_empty(cq)) {
962                 struct lock_list *lock;
963
964                 __cq_dequeue(cq, (unsigned long *)&lock);
965
966                 if (!lock->class) {
967                         ret = -2;
968                         goto exit;
969                 }
970
971                 if (forward)
972                         head = &lock->class->locks_after;
973                 else
974                         head = &lock->class->locks_before;
975
976                 list_for_each_entry(entry, head, entry) {
977                         if (!lock_accessed(entry)) {
978                                 unsigned int cq_depth;
979                                 mark_lock_accessed(entry, lock);
980                                 if (match(entry, data)) {
981                                         *target_entry = entry;
982                                         ret = 0;
983                                         goto exit;
984                                 }
985
986                                 if (__cq_enqueue(cq, (unsigned long)entry)) {
987                                         ret = -1;
988                                         goto exit;
989                                 }
990                                 cq_depth = __cq_get_elem_count(cq);
991                                 if (max_bfs_queue_depth < cq_depth)
992                                         max_bfs_queue_depth = cq_depth;
993                         }
994                 }
995         }
996 exit:
997         return ret;
998 }
999
1000 static inline int __bfs_forwards(struct lock_list *src_entry,
1001                         void *data,
1002                         int (*match)(struct lock_list *entry, void *data),
1003                         struct lock_list **target_entry)
1004 {
1005         return __bfs(src_entry, data, match, target_entry, 1);
1006
1007 }
1008
1009 static inline int __bfs_backwards(struct lock_list *src_entry,
1010                         void *data,
1011                         int (*match)(struct lock_list *entry, void *data),
1012                         struct lock_list **target_entry)
1013 {
1014         return __bfs(src_entry, data, match, target_entry, 0);
1015
1016 }
1017
1018 /*
1019  * Recursive, forwards-direction lock-dependency checking, used for
1020  * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
1021  * checking.
1022  */
1023
1024 /*
1025  * Print a dependency chain entry (this is only done when a deadlock
1026  * has been detected):
1027  */
1028 static noinline int
1029 print_circular_bug_entry(struct lock_list *target, int depth)
1030 {
1031         if (debug_locks_silent)
1032                 return 0;
1033         printk("\n-> #%u", depth);
1034         print_lock_name(target->class);
1035         printk(":\n");
1036         print_stack_trace(&target->trace, 6);
1037
1038         return 0;
1039 }
1040
1041 /*
1042  * When a circular dependency is detected, print the
1043  * header first:
1044  */
1045 static noinline int
1046 print_circular_bug_header(struct lock_list *entry, unsigned int depth,
1047                         struct held_lock *check_src,
1048                         struct held_lock *check_tgt)
1049 {
1050         struct task_struct *curr = current;
1051
1052         if (debug_locks_silent)
1053                 return 0;
1054
1055         printk("\n=======================================================\n");
1056         printk(  "[ INFO: possible circular locking dependency detected ]\n");
1057         print_kernel_version();
1058         printk(  "-------------------------------------------------------\n");
1059         printk("%s/%d is trying to acquire lock:\n",
1060                 curr->comm, task_pid_nr(curr));
1061         print_lock(check_src);
1062         printk("\nbut task is already holding lock:\n");
1063         print_lock(check_tgt);
1064         printk("\nwhich lock already depends on the new lock.\n\n");
1065         printk("\nthe existing dependency chain (in reverse order) is:\n");
1066
1067         print_circular_bug_entry(entry, depth);
1068
1069         return 0;
1070 }
1071
1072 static inline int class_equal(struct lock_list *entry, void *data)
1073 {
1074         return entry->class == data;
1075 }
1076
1077 static noinline int print_circular_bug(struct lock_list *this,
1078                                 struct lock_list *target,
1079                                 struct held_lock *check_src,
1080                                 struct held_lock *check_tgt)
1081 {
1082         struct task_struct *curr = current;
1083         struct lock_list *parent;
1084         int depth;
1085
1086         if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1087                 return 0;
1088
1089         if (!save_trace(&this->trace))
1090                 return 0;
1091
1092         depth = get_lock_depth(target);
1093
1094         print_circular_bug_header(target, depth, check_src, check_tgt);
1095
1096         parent = get_lock_parent(target);
1097
1098         while (parent) {
1099                 print_circular_bug_entry(parent, --depth);
1100                 parent = get_lock_parent(parent);
1101         }
1102
1103         printk("\nother info that might help us debug this:\n\n");
1104         lockdep_print_held_locks(curr);
1105
1106         printk("\nstack backtrace:\n");
1107         dump_stack();
1108
1109         return 0;
1110 }
1111
1112 static noinline int print_bfs_bug(int ret)
1113 {
1114         if (!debug_locks_off_graph_unlock())
1115                 return 0;
1116
1117         WARN(1, "lockdep bfs error:%d\n", ret);
1118
1119         return 0;
1120 }
1121
1122 static int noop_count(struct lock_list *entry, void *data)
1123 {
1124         (*(unsigned long *)data)++;
1125         return 0;
1126 }
1127
1128 unsigned long __lockdep_count_forward_deps(struct lock_list *this)
1129 {
1130         unsigned long  count = 0;
1131         struct lock_list *uninitialized_var(target_entry);
1132
1133         __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
1134
1135         return count;
1136 }
1137 unsigned long lockdep_count_forward_deps(struct lock_class *class)
1138 {
1139         unsigned long ret, flags;
1140         struct lock_list this;
1141
1142         this.parent = NULL;
1143         this.class = class;
1144
1145         local_irq_save(flags);
1146         __raw_spin_lock(&lockdep_lock);
1147         ret = __lockdep_count_forward_deps(&this);
1148         __raw_spin_unlock(&lockdep_lock);
1149         local_irq_restore(flags);
1150
1151         return ret;
1152 }
1153
1154 unsigned long __lockdep_count_backward_deps(struct lock_list *this)
1155 {
1156         unsigned long  count = 0;
1157         struct lock_list *uninitialized_var(target_entry);
1158
1159         __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
1160
1161         return count;
1162 }
1163
1164 unsigned long lockdep_count_backward_deps(struct lock_class *class)
1165 {
1166         unsigned long ret, flags;
1167         struct lock_list this;
1168
1169         this.parent = NULL;
1170         this.class = class;
1171
1172         local_irq_save(flags);
1173         __raw_spin_lock(&lockdep_lock);
1174         ret = __lockdep_count_backward_deps(&this);
1175         __raw_spin_unlock(&lockdep_lock);
1176         local_irq_restore(flags);
1177
1178         return ret;
1179 }
1180
1181 /*
1182  * Prove that the dependency graph starting at <entry> can not
1183  * lead to <target>. Print an error and return 0 if it does.
1184  */
1185 static noinline int
1186 check_noncircular(struct lock_list *root, struct lock_class *target,
1187                 struct lock_list **target_entry)
1188 {
1189         int result;
1190
1191         debug_atomic_inc(&nr_cyclic_checks);
1192
1193         result = __bfs_forwards(root, target, class_equal, target_entry);
1194
1195         return result;
1196 }
1197
1198 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
1199 /*
1200  * Forwards and backwards subgraph searching, for the purposes of
1201  * proving that two subgraphs can be connected by a new dependency
1202  * without creating any illegal irq-safe -> irq-unsafe lock dependency.
1203  */
1204
1205
1206 #define   BFS_PROCESS_RET(ret)  do { \
1207                                         if (ret < 0) \
1208                                                 return print_bfs_bug(ret); \
1209                                         if (ret == 1) \
1210                                                 return 1; \
1211                                 } while (0)
1212
1213 static inline int usage_match(struct lock_list *entry, void *bit)
1214 {
1215         return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
1216 }
1217
1218
1219
1220 /*
1221  * Find a node in the forwards-direction dependency sub-graph starting
1222  * at @root->class that matches @bit.
1223  *
1224  * Return 0 if such a node exists in the subgraph, and put that node
1225  * into *@target_entry.
1226  *
1227  * Return 1 otherwise and keep *@target_entry unchanged.
1228  * Return <0 on error.
1229  */
1230 static int
1231 find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
1232                         struct lock_list **target_entry)
1233 {
1234         int result;
1235
1236         debug_atomic_inc(&nr_find_usage_forwards_checks);
1237
1238         result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
1239
1240         return result;
1241 }
1242
1243 /*
1244  * Find a node in the backwards-direction dependency sub-graph starting
1245  * at @root->class that matches @bit.
1246  *
1247  * Return 0 if such a node exists in the subgraph, and put that node
1248  * into *@target_entry.
1249  *
1250  * Return 1 otherwise and keep *@target_entry unchanged.
1251  * Return <0 on error.
1252  */
1253 static int
1254 find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
1255                         struct lock_list **target_entry)
1256 {
1257         int result;
1258
1259         debug_atomic_inc(&nr_find_usage_backwards_checks);
1260
1261         result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
1262
1263         return result;
1264 }
1265
1266
1267 static int
1268 print_bad_irq_dependency(struct task_struct *curr,
1269                          struct lock_list *prev_root,
1270                          struct lock_list *next_root,
1271                          struct lock_list *backwards_entry,
1272                          struct lock_list *forwards_entry,
1273                          struct held_lock *prev,
1274                          struct held_lock *next,
1275                          enum lock_usage_bit bit1,
1276                          enum lock_usage_bit bit2,
1277                          const char *irqclass)
1278 {
1279         if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1280                 return 0;
1281
1282         printk("\n======================================================\n");
1283         printk(  "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
1284                 irqclass, irqclass);
1285         print_kernel_version();
1286         printk(  "------------------------------------------------------\n");
1287         printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
1288                 curr->comm, task_pid_nr(curr),
1289                 curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
1290                 curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
1291                 curr->hardirqs_enabled,
1292                 curr->softirqs_enabled);
1293         print_lock(next);
1294
1295         printk("\nand this task is already holding:\n");
1296         print_lock(prev);
1297         printk("which would create a new lock dependency:\n");
1298         print_lock_name(hlock_class(prev));
1299         printk(" ->");
1300         print_lock_name(hlock_class(next));
1301         printk("\n");
1302
1303         printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
1304                 irqclass);
1305         print_lock_name(backwards_entry->class);
1306         printk("\n... which became %s-irq-safe at:\n", irqclass);
1307
1308         print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
1309
1310         printk("\nto a %s-irq-unsafe lock:\n", irqclass);
1311         print_lock_name(forwards_entry->class);
1312         printk("\n... which became %s-irq-unsafe at:\n", irqclass);
1313         printk("...");
1314
1315         print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
1316
1317         printk("\nother info that might help us debug this:\n\n");
1318         lockdep_print_held_locks(curr);
1319
1320         printk("\nthe dependencies between %s-irq-safe lock", irqclass);
1321         printk(" and the holding lock:\n");
1322         if (!save_trace(&prev_root->trace))
1323                 return 0;
1324         print_shortest_lock_dependencies(backwards_entry, prev_root);
1325
1326         printk("\nthe dependencies between the lock to be acquired");
1327         printk(" and %s-irq-unsafe lock:\n", irqclass);
1328         if (!save_trace(&next_root->trace))
1329                 return 0;
1330         print_shortest_lock_dependencies(forwards_entry, next_root);
1331
1332         printk("\nstack backtrace:\n");
1333         dump_stack();
1334
1335         return 0;
1336 }
1337
1338 static int
1339 check_usage(struct task_struct *curr, struct held_lock *prev,
1340             struct held_lock *next, enum lock_usage_bit bit_backwards,
1341             enum lock_usage_bit bit_forwards, const char *irqclass)
1342 {
1343         int ret;
1344         struct lock_list this, that;
1345         struct lock_list *uninitialized_var(target_entry);
1346         struct lock_list *uninitialized_var(target_entry1);
1347
1348         this.parent = NULL;
1349
1350         this.class = hlock_class(prev);
1351         ret = find_usage_backwards(&this, bit_backwards, &target_entry);
1352         BFS_PROCESS_RET(ret);
1353
1354         that.parent = NULL;
1355         that.class = hlock_class(next);
1356         ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
1357         BFS_PROCESS_RET(ret);
1358
1359         return print_bad_irq_dependency(curr, &this, &that,
1360                         target_entry, target_entry1,
1361                         prev, next,
1362                         bit_backwards, bit_forwards, irqclass);
1363 }
1364
1365 static const char *state_names[] = {
1366 #define LOCKDEP_STATE(__STATE) \
1367         __stringify(__STATE),
1368 #include "lockdep_states.h"
1369 #undef LOCKDEP_STATE
1370 };
1371
1372 static const char *state_rnames[] = {
1373 #define LOCKDEP_STATE(__STATE) \
1374         __stringify(__STATE)"-READ",
1375 #include "lockdep_states.h"
1376 #undef LOCKDEP_STATE
1377 };
1378
1379 static inline const char *state_name(enum lock_usage_bit bit)
1380 {
1381         return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
1382 }
1383
1384 static int exclusive_bit(int new_bit)
1385 {
1386         /*
1387          * USED_IN
1388          * USED_IN_READ
1389          * ENABLED
1390          * ENABLED_READ
1391          *
1392          * bit 0 - write/read
1393          * bit 1 - used_in/enabled
1394          * bit 2+  state
1395          */
1396
1397         int state = new_bit & ~3;
1398         int dir = new_bit & 2;
1399
1400         /*
1401          * keep state, bit flip the direction and strip read.
1402          */
1403         return state | (dir ^ 2);
1404 }
1405
1406 static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
1407                            struct held_lock *next, enum lock_usage_bit bit)
1408 {
1409         /*
1410          * Prove that the new dependency does not connect a hardirq-safe
1411          * lock with a hardirq-unsafe lock - to achieve this we search
1412          * the backwards-subgraph starting at <prev>, and the
1413          * forwards-subgraph starting at <next>:
1414          */
1415         if (!check_usage(curr, prev, next, bit,
1416                            exclusive_bit(bit), state_name(bit)))
1417                 return 0;
1418
1419         bit++; /* _READ */
1420
1421         /*
1422          * Prove that the new dependency does not connect a hardirq-safe-read
1423          * lock with a hardirq-unsafe lock - to achieve this we search
1424          * the backwards-subgraph starting at <prev>, and the
1425          * forwards-subgraph starting at <next>:
1426          */
1427         if (!check_usage(curr, prev, next, bit,
1428                            exclusive_bit(bit), state_name(bit)))
1429                 return 0;
1430
1431         return 1;
1432 }
1433
1434 static int
1435 check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1436                 struct held_lock *next)
1437 {
1438 #define LOCKDEP_STATE(__STATE)                                          \
1439         if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
1440                 return 0;
1441 #include "lockdep_states.h"
1442 #undef LOCKDEP_STATE
1443
1444         return 1;
1445 }
1446
1447 static void inc_chains(void)
1448 {
1449         if (current->hardirq_context)
1450                 nr_hardirq_chains++;
1451         else {
1452                 if (current->softirq_context)
1453                         nr_softirq_chains++;
1454                 else
1455                         nr_process_chains++;
1456         }
1457 }
1458
1459 #else
1460
1461 static inline int
1462 check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1463                 struct held_lock *next)
1464 {
1465         return 1;
1466 }
1467
1468 static inline void inc_chains(void)
1469 {
1470         nr_process_chains++;
1471 }
1472
1473 #endif
1474
1475 static int
1476 print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
1477                    struct held_lock *next)
1478 {
1479         if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1480                 return 0;
1481
1482         printk("\n=============================================\n");
1483         printk(  "[ INFO: possible recursive locking detected ]\n");
1484         print_kernel_version();
1485         printk(  "---------------------------------------------\n");
1486         printk("%s/%d is trying to acquire lock:\n",
1487                 curr->comm, task_pid_nr(curr));
1488         print_lock(next);
1489         printk("\nbut task is already holding lock:\n");
1490         print_lock(prev);
1491
1492         printk("\nother info that might help us debug this:\n");
1493         lockdep_print_held_locks(curr);
1494
1495         printk("\nstack backtrace:\n");
1496         dump_stack();
1497
1498         return 0;
1499 }
1500
1501 /*
1502  * Check whether we are holding such a class already.
1503  *
1504  * (Note that this has to be done separately, because the graph cannot
1505  * detect such classes of deadlocks.)
1506  *
1507  * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
1508  */
1509 static int
1510 check_deadlock(struct task_struct *curr, struct held_lock *next,
1511                struct lockdep_map *next_instance, int read)
1512 {
1513         struct held_lock *prev;
1514         struct held_lock *nest = NULL;
1515         int i;
1516
1517         for (i = 0; i < curr->lockdep_depth; i++) {
1518                 prev = curr->held_locks + i;
1519
1520                 if (prev->instance == next->nest_lock)
1521                         nest = prev;
1522
1523                 if (hlock_class(prev) != hlock_class(next))
1524                         continue;
1525
1526                 /*
1527                  * Allow read-after-read recursion of the same
1528                  * lock class (i.e. read_lock(lock)+read_lock(lock)):
1529                  */
1530                 if ((read == 2) && prev->read)
1531                         return 2;
1532
1533                 /*
1534                  * We're holding the nest_lock, which serializes this lock's
1535                  * nesting behaviour.
1536                  */
1537                 if (nest)
1538                         return 2;
1539
1540                 return print_deadlock_bug(curr, prev, next);
1541         }
1542         return 1;
1543 }
1544
1545 /*
1546  * There was a chain-cache miss, and we are about to add a new dependency
1547  * to a previous lock. We recursively validate the following rules:
1548  *
1549  *  - would the adding of the <prev> -> <next> dependency create a
1550  *    circular dependency in the graph? [== circular deadlock]
1551  *
1552  *  - does the new prev->next dependency connect any hardirq-safe lock
1553  *    (in the full backwards-subgraph starting at <prev>) with any
1554  *    hardirq-unsafe lock (in the full forwards-subgraph starting at
1555  *    <next>)? [== illegal lock inversion with hardirq contexts]
1556  *
1557  *  - does the new prev->next dependency connect any softirq-safe lock
1558  *    (in the full backwards-subgraph starting at <prev>) with any
1559  *    softirq-unsafe lock (in the full forwards-subgraph starting at
1560  *    <next>)? [== illegal lock inversion with softirq contexts]
1561  *
1562  * any of these scenarios could lead to a deadlock.
1563  *
1564  * Then if all the validations pass, we add the forwards and backwards
1565  * dependency.
1566  */
1567 static int
1568 check_prev_add(struct task_struct *curr, struct held_lock *prev,
1569                struct held_lock *next, int distance)
1570 {
1571         struct lock_list *entry;
1572         int ret;
1573         struct lock_list this;
1574         struct lock_list *uninitialized_var(target_entry);
1575
1576         /*
1577          * Prove that the new <prev> -> <next> dependency would not
1578          * create a circular dependency in the graph. (We do this by
1579          * forward-recursing into the graph starting at <next>, and
1580          * checking whether we can reach <prev>.)
1581          *
1582          * We are using global variables to control the recursion, to
1583          * keep the stackframe size of the recursive functions low:
1584          */
1585         this.class = hlock_class(next);
1586         this.parent = NULL;
1587         ret = check_noncircular(&this, hlock_class(prev), &target_entry);
1588         if (unlikely(!ret))
1589                 return print_circular_bug(&this, target_entry, next, prev);
1590         else if (unlikely(ret < 0))
1591                 return print_bfs_bug(ret);
1592
1593         if (!check_prev_add_irq(curr, prev, next))
1594                 return 0;
1595
1596         /*
1597          * For recursive read-locks we do all the dependency checks,
1598          * but we dont store read-triggered dependencies (only
1599          * write-triggered dependencies). This ensures that only the
1600          * write-side dependencies matter, and that if for example a
1601          * write-lock never takes any other locks, then the reads are
1602          * equivalent to a NOP.
1603          */
1604         if (next->read == 2 || prev->read == 2)
1605                 return 1;
1606         /*
1607          * Is the <prev> -> <next> dependency already present?
1608          *
1609          * (this may occur even though this is a new chain: consider
1610          *  e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
1611          *  chains - the second one will be new, but L1 already has
1612          *  L2 added to its dependency list, due to the first chain.)
1613          */
1614         list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
1615                 if (entry->class == hlock_class(next)) {
1616                         if (distance == 1)
1617                                 entry->distance = 1;
1618                         return 2;
1619                 }
1620         }
1621
1622         /*
1623          * Ok, all validations passed, add the new lock
1624          * to the previous lock's dependency list:
1625          */
1626         ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
1627                                &hlock_class(prev)->locks_after,
1628                                next->acquire_ip, distance);
1629
1630         if (!ret)
1631                 return 0;
1632
1633         ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
1634                                &hlock_class(next)->locks_before,
1635                                next->acquire_ip, distance);
1636         if (!ret)
1637                 return 0;
1638
1639         /*
1640          * Debugging printouts:
1641          */
1642         if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
1643                 graph_unlock();
1644                 printk("\n new dependency: ");
1645                 print_lock_name(hlock_class(prev));
1646                 printk(" => ");
1647                 print_lock_name(hlock_class(next));
1648                 printk("\n");
1649                 dump_stack();
1650                 return graph_lock();
1651         }
1652         return 1;
1653 }
1654
1655 /*
1656  * Add the dependency to all directly-previous locks that are 'relevant'.
1657  * The ones that are relevant are (in increasing distance from curr):
1658  * all consecutive trylock entries and the final non-trylock entry - or
1659  * the end of this context's lock-chain - whichever comes first.
1660  */
1661 static int
1662 check_prevs_add(struct task_struct *curr, struct held_lock *next)
1663 {
1664         int depth = curr->lockdep_depth;
1665         struct held_lock *hlock;
1666
1667         /*
1668          * Debugging checks.
1669          *
1670          * Depth must not be zero for a non-head lock:
1671          */
1672         if (!depth)
1673                 goto out_bug;
1674         /*
1675          * At least two relevant locks must exist for this
1676          * to be a head:
1677          */
1678         if (curr->held_locks[depth].irq_context !=
1679                         curr->held_locks[depth-1].irq_context)
1680                 goto out_bug;
1681
1682         for (;;) {
1683                 int distance = curr->lockdep_depth - depth + 1;
1684                 hlock = curr->held_locks + depth-1;
1685                 /*
1686                  * Only non-recursive-read entries get new dependencies
1687                  * added:
1688                  */
1689                 if (hlock->read != 2) {
1690                         if (!check_prev_add(curr, hlock, next, distance))
1691                                 return 0;
1692                         /*
1693                          * Stop after the first non-trylock entry,
1694                          * as non-trylock entries have added their
1695                          * own direct dependencies already, so this
1696                          * lock is connected to them indirectly:
1697                          */
1698                         if (!hlock->trylock)
1699                                 break;
1700                 }
1701                 depth--;
1702                 /*
1703                  * End of lock-stack?
1704                  */
1705                 if (!depth)
1706                         break;
1707                 /*
1708                  * Stop the search if we cross into another context:
1709                  */
1710                 if (curr->held_locks[depth].irq_context !=
1711                                 curr->held_locks[depth-1].irq_context)
1712                         break;
1713         }
1714         return 1;
1715 out_bug:
1716         if (!debug_locks_off_graph_unlock())
1717                 return 0;
1718
1719         WARN_ON(1);
1720
1721         return 0;
1722 }
1723
1724 unsigned long nr_lock_chains;
1725 struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
1726 int nr_chain_hlocks;
1727 static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
1728
1729 struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
1730 {
1731         return lock_classes + chain_hlocks[chain->base + i];
1732 }
1733
1734 /*
1735  * Look up a dependency chain. If the key is not present yet then
1736  * add it and return 1 - in this case the new dependency chain is
1737  * validated. If the key is already hashed, return 0.
1738  * (On return with 1 graph_lock is held.)
1739  */
1740 static inline int lookup_chain_cache(struct task_struct *curr,
1741                                      struct held_lock *hlock,
1742                                      u64 chain_key)
1743 {
1744         struct lock_class *class = hlock_class(hlock);
1745         struct list_head *hash_head = chainhashentry(chain_key);
1746         struct lock_chain *chain;
1747         struct held_lock *hlock_curr, *hlock_next;
1748         int i, j, n, cn;
1749
1750         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
1751                 return 0;
1752         /*
1753          * We can walk it lock-free, because entries only get added
1754          * to the hash:
1755          */
1756         list_for_each_entry(chain, hash_head, entry) {
1757                 if (chain->chain_key == chain_key) {
1758 cache_hit:
1759                         debug_atomic_inc(&chain_lookup_hits);
1760                         if (very_verbose(class))
1761                                 printk("\nhash chain already cached, key: "
1762                                         "%016Lx tail class: [%p] %s\n",
1763                                         (unsigned long long)chain_key,
1764                                         class->key, class->name);
1765                         return 0;
1766                 }
1767         }
1768         if (very_verbose(class))
1769                 printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
1770                         (unsigned long long)chain_key, class->key, class->name);
1771         /*
1772          * Allocate a new chain entry from the static array, and add
1773          * it to the hash:
1774          */
1775         if (!graph_lock())
1776                 return 0;
1777         /*
1778          * We have to walk the chain again locked - to avoid duplicates:
1779          */
1780         list_for_each_entry(chain, hash_head, entry) {
1781                 if (chain->chain_key == chain_key) {
1782                         graph_unlock();
1783                         goto cache_hit;
1784                 }
1785         }
1786         if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
1787                 if (!debug_locks_off_graph_unlock())
1788                         return 0;
1789
1790                 printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
1791                 printk("turning off the locking correctness validator.\n");
1792                 dump_stack();
1793                 return 0;
1794         }
1795         chain = lock_chains + nr_lock_chains++;
1796         chain->chain_key = chain_key;
1797         chain->irq_context = hlock->irq_context;
1798         /* Find the first held_lock of current chain */
1799         hlock_next = hlock;
1800         for (i = curr->lockdep_depth - 1; i >= 0; i--) {
1801                 hlock_curr = curr->held_locks + i;
1802                 if (hlock_curr->irq_context != hlock_next->irq_context)
1803                         break;
1804                 hlock_next = hlock;
1805         }
1806         i++;
1807         chain->depth = curr->lockdep_depth + 1 - i;
1808         cn = nr_chain_hlocks;
1809         while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) {
1810                 n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth);
1811                 if (n == cn)
1812                         break;
1813                 cn = n;
1814         }
1815         if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
1816                 chain->base = cn;
1817                 for (j = 0; j < chain->depth - 1; j++, i++) {
1818                         int lock_id = curr->held_locks[i].class_idx - 1;
1819                         chain_hlocks[chain->base + j] = lock_id;
1820                 }
1821                 chain_hlocks[chain->base + j] = class - lock_classes;
1822         }
1823         list_add_tail_rcu(&chain->entry, hash_head);
1824         debug_atomic_inc(&chain_lookup_misses);
1825         inc_chains();
1826
1827         return 1;
1828 }
1829
1830 static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
1831                 struct held_lock *hlock, int chain_head, u64 chain_key)
1832 {
1833         /*
1834          * Trylock needs to maintain the stack of held locks, but it
1835          * does not add new dependencies, because trylock can be done
1836          * in any order.
1837          *
1838          * We look up the chain_key and do the O(N^2) check and update of
1839          * the dependencies only if this is a new dependency chain.
1840          * (If lookup_chain_cache() returns with 1 it acquires
1841          * graph_lock for us)
1842          */
1843         if (!hlock->trylock && (hlock->check == 2) &&
1844             lookup_chain_cache(curr, hlock, chain_key)) {
1845                 /*
1846                  * Check whether last held lock:
1847                  *
1848                  * - is irq-safe, if this lock is irq-unsafe
1849                  * - is softirq-safe, if this lock is hardirq-unsafe
1850                  *
1851                  * And check whether the new lock's dependency graph
1852                  * could lead back to the previous lock.
1853                  *
1854                  * any of these scenarios could lead to a deadlock. If
1855                  * All validations
1856                  */
1857                 int ret = check_deadlock(curr, hlock, lock, hlock->read);
1858
1859                 if (!ret)
1860                         return 0;
1861                 /*
1862                  * Mark recursive read, as we jump over it when
1863                  * building dependencies (just like we jump over
1864                  * trylock entries):
1865                  */
1866                 if (ret == 2)
1867                         hlock->read = 2;
1868                 /*
1869                  * Add dependency only if this lock is not the head
1870                  * of the chain, and if it's not a secondary read-lock:
1871                  */
1872                 if (!chain_head && ret != 2)
1873                         if (!check_prevs_add(curr, hlock))
1874                                 return 0;
1875                 graph_unlock();
1876         } else
1877                 /* after lookup_chain_cache(): */
1878                 if (unlikely(!debug_locks))
1879                         return 0;
1880
1881         return 1;
1882 }
1883 #else
1884 static inline int validate_chain(struct task_struct *curr,
1885                 struct lockdep_map *lock, struct held_lock *hlock,
1886                 int chain_head, u64 chain_key)
1887 {
1888         return 1;
1889 }
1890 #endif
1891
1892 /*
1893  * We are building curr_chain_key incrementally, so double-check
1894  * it from scratch, to make sure that it's done correctly:
1895  */
1896 static void check_chain_key(struct task_struct *curr)
1897 {
1898 #ifdef CONFIG_DEBUG_LOCKDEP
1899         struct held_lock *hlock, *prev_hlock = NULL;
1900         unsigned int i, id;
1901         u64 chain_key = 0;
1902
1903         for (i = 0; i < curr->lockdep_depth; i++) {
1904                 hlock = curr->held_locks + i;
1905                 if (chain_key != hlock->prev_chain_key) {
1906                         debug_locks_off();
1907                         WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
1908                                 curr->lockdep_depth, i,
1909                                 (unsigned long long)chain_key,
1910                                 (unsigned long long)hlock->prev_chain_key);
1911                         return;
1912                 }
1913                 id = hlock->class_idx - 1;
1914                 if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
1915                         return;
1916
1917                 if (prev_hlock && (prev_hlock->irq_context !=
1918                                                         hlock->irq_context))
1919                         chain_key = 0;
1920                 chain_key = iterate_chain_key(chain_key, id);
1921                 prev_hlock = hlock;
1922         }
1923         if (chain_key != curr->curr_chain_key) {
1924                 debug_locks_off();
1925                 WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
1926                         curr->lockdep_depth, i,
1927                         (unsigned long long)chain_key,
1928                         (unsigned long long)curr->curr_chain_key);
1929         }
1930 #endif
1931 }
1932
1933 static int
1934 print_usage_bug(struct task_struct *curr, struct held_lock *this,
1935                 enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
1936 {
1937         if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1938                 return 0;
1939
1940         printk("\n=================================\n");
1941         printk(  "[ INFO: inconsistent lock state ]\n");
1942         print_kernel_version();
1943         printk(  "---------------------------------\n");
1944
1945         printk("inconsistent {%s} -> {%s} usage.\n",
1946                 usage_str[prev_bit], usage_str[new_bit]);
1947
1948         printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
1949                 curr->comm, task_pid_nr(curr),
1950                 trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
1951                 trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
1952                 trace_hardirqs_enabled(curr),
1953                 trace_softirqs_enabled(curr));
1954         print_lock(this);
1955
1956         printk("{%s} state was registered at:\n", usage_str[prev_bit]);
1957         print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
1958
1959         print_irqtrace_events(curr);
1960         printk("\nother info that might help us debug this:\n");
1961         lockdep_print_held_locks(curr);
1962
1963         printk("\nstack backtrace:\n");
1964         dump_stack();
1965
1966         return 0;
1967 }
1968
1969 /*
1970  * Print out an error if an invalid bit is set:
1971  */
1972 static inline int
1973 valid_state(struct task_struct *curr, struct held_lock *this,
1974             enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
1975 {
1976         if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
1977                 return print_usage_bug(curr, this, bad_bit, new_bit);
1978         return 1;
1979 }
1980
1981 static int mark_lock(struct task_struct *curr, struct held_lock *this,
1982                      enum lock_usage_bit new_bit);
1983
1984 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
1985
1986 /*
1987  * print irq inversion bug:
1988  */
1989 static int
1990 print_irq_inversion_bug(struct task_struct *curr,
1991                         struct lock_list *root, struct lock_list *other,
1992                         struct held_lock *this, int forwards,
1993                         const char *irqclass)
1994 {
1995         if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1996                 return 0;
1997
1998         printk("\n=========================================================\n");
1999         printk(  "[ INFO: possible irq lock inversion dependency detected ]\n");
2000         print_kernel_version();
2001         printk(  "---------------------------------------------------------\n");
2002         printk("%s/%d just changed the state of lock:\n",
2003                 curr->comm, task_pid_nr(curr));
2004         print_lock(this);
2005         if (forwards)
2006                 printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
2007         else
2008                 printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
2009         print_lock_name(other->class);
2010         printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
2011
2012         printk("\nother info that might help us debug this:\n");
2013         lockdep_print_held_locks(curr);
2014
2015         printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
2016         if (!save_trace(&root->trace))
2017                 return 0;
2018         print_shortest_lock_dependencies(other, root);
2019
2020         printk("\nstack backtrace:\n");
2021         dump_stack();
2022
2023         return 0;
2024 }
2025
2026 /*
2027  * Prove that in the forwards-direction subgraph starting at <this>
2028  * there is no lock matching <mask>:
2029  */
2030 static int
2031 check_usage_forwards(struct task_struct *curr, struct held_lock *this,
2032                      enum lock_usage_bit bit, const char *irqclass)
2033 {
2034         int ret;
2035         struct lock_list root;
2036         struct lock_list *uninitialized_var(target_entry);
2037
2038         root.parent = NULL;
2039         root.class = hlock_class(this);
2040         ret = find_usage_forwards(&root, bit, &target_entry);
2041         BFS_PROCESS_RET(ret);
2042
2043         return print_irq_inversion_bug(curr, &root, target_entry,
2044                                         this, 1, irqclass);
2045 }
2046
2047 /*
2048  * Prove that in the backwards-direction subgraph starting at <this>
2049  * there is no lock matching <mask>:
2050  */
2051 static int
2052 check_usage_backwards(struct task_struct *curr, struct held_lock *this,
2053                       enum lock_usage_bit bit, const char *irqclass)
2054 {
2055         int ret;
2056         struct lock_list root;
2057         struct lock_list *uninitialized_var(target_entry);
2058
2059         root.parent = NULL;
2060         root.class = hlock_class(this);
2061         ret = find_usage_backwards(&root, bit, &target_entry);
2062         BFS_PROCESS_RET(ret);
2063
2064         return print_irq_inversion_bug(curr, &root, target_entry,
2065                                         this, 1, irqclass);
2066 }
2067
2068 void print_irqtrace_events(struct task_struct *curr)
2069 {
2070         printk("irq event stamp: %u\n", curr->irq_events);
2071         printk("hardirqs last  enabled at (%u): ", curr->hardirq_enable_event);
2072         print_ip_sym(curr->hardirq_enable_ip);
2073         printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
2074         print_ip_sym(curr->hardirq_disable_ip);
2075         printk("softirqs last  enabled at (%u): ", curr->softirq_enable_event);
2076         print_ip_sym(curr->softirq_enable_ip);
2077         printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
2078         print_ip_sym(curr->softirq_disable_ip);
2079 }
2080
2081 static int HARDIRQ_verbose(struct lock_class *class)
2082 {
2083 #if HARDIRQ_VERBOSE
2084         return class_filter(class);
2085 #endif
2086         return 0;
2087 }
2088
2089 static int SOFTIRQ_verbose(struct lock_class *class)
2090 {
2091 #if SOFTIRQ_VERBOSE
2092         return class_filter(class);
2093 #endif
2094         return 0;
2095 }
2096
2097 static int RECLAIM_FS_verbose(struct lock_class *class)
2098 {
2099 #if RECLAIM_VERBOSE
2100         return class_filter(class);
2101 #endif
2102         return 0;
2103 }
2104
2105 #define STRICT_READ_CHECKS      1
2106
2107 static int (*state_verbose_f[])(struct lock_class *class) = {
2108 #define LOCKDEP_STATE(__STATE) \
2109         __STATE##_verbose,
2110 #include "lockdep_states.h"
2111 #undef LOCKDEP_STATE
2112 };
2113
2114 static inline int state_verbose(enum lock_usage_bit bit,
2115                                 struct lock_class *class)
2116 {
2117         return state_verbose_f[bit >> 2](class);
2118 }
2119
2120 typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
2121                              enum lock_usage_bit bit, const char *name);
2122
2123 static int
2124 mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2125                 enum lock_usage_bit new_bit)
2126 {
2127         int excl_bit = exclusive_bit(new_bit);
2128         int read = new_bit & 1;
2129         int dir = new_bit & 2;
2130
2131         /*
2132          * mark USED_IN has to look forwards -- to ensure no dependency
2133          * has ENABLED state, which would allow recursion deadlocks.
2134          *
2135          * mark ENABLED has to look backwards -- to ensure no dependee
2136          * has USED_IN state, which, again, would allow  recursion deadlocks.
2137          */
2138         check_usage_f usage = dir ?
2139                 check_usage_backwards : check_usage_forwards;
2140
2141         /*
2142          * Validate that this particular lock does not have conflicting
2143          * usage states.
2144          */
2145         if (!valid_state(curr, this, new_bit, excl_bit))
2146                 return 0;
2147
2148         /*
2149          * Validate that the lock dependencies don't have conflicting usage
2150          * states.
2151          */
2152         if ((!read || !dir || STRICT_READ_CHECKS) &&
2153                         !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
2154                 return 0;
2155
2156         /*
2157          * Check for read in write conflicts
2158          */
2159         if (!read) {
2160                 if (!valid_state(curr, this, new_bit, excl_bit + 1))
2161                         return 0;
2162
2163                 if (STRICT_READ_CHECKS &&
2164                         !usage(curr, this, excl_bit + 1,
2165                                 state_name(new_bit + 1)))
2166                         return 0;
2167         }
2168
2169         if (state_verbose(new_bit, hlock_class(this)))
2170                 return 2;
2171
2172         return 1;
2173 }
2174
2175 enum mark_type {
2176 #define LOCKDEP_STATE(__STATE)  __STATE,
2177 #include "lockdep_states.h"
2178 #undef LOCKDEP_STATE
2179 };
2180
2181 /*
2182  * Mark all held locks with a usage bit:
2183  */
2184 static int
2185 mark_held_locks(struct task_struct *curr, enum mark_type mark)
2186 {
2187         enum lock_usage_bit usage_bit;
2188         struct held_lock *hlock;
2189         int i;
2190
2191         for (i = 0; i < curr->lockdep_depth; i++) {
2192                 hlock = curr->held_locks + i;
2193
2194                 usage_bit = 2 + (mark << 2); /* ENABLED */
2195                 if (hlock->read)
2196                         usage_bit += 1; /* READ */
2197
2198                 BUG_ON(usage_bit >= LOCK_USAGE_STATES);
2199
2200                 if (!mark_lock(curr, hlock, usage_bit))
2201                         return 0;
2202         }
2203
2204         return 1;
2205 }
2206
2207 /*
2208  * Debugging helper: via this flag we know that we are in
2209  * 'early bootup code', and will warn about any invalid irqs-on event:
2210  */
2211 static int early_boot_irqs_enabled;
2212
2213 void early_boot_irqs_off(void)
2214 {
2215         early_boot_irqs_enabled = 0;
2216 }
2217
2218 void early_boot_irqs_on(void)
2219 {
2220         early_boot_irqs_enabled = 1;
2221 }
2222
2223 /*
2224  * Hardirqs will be enabled:
2225  */
2226 void trace_hardirqs_on_caller(unsigned long ip)
2227 {
2228         struct task_struct *curr = current;
2229
2230         time_hardirqs_on(CALLER_ADDR0, ip);
2231
2232         if (unlikely(!debug_locks || current->lockdep_recursion))
2233                 return;
2234
2235         if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
2236                 return;
2237
2238         if (unlikely(curr->hardirqs_enabled)) {
2239                 debug_atomic_inc(&redundant_hardirqs_on);
2240                 return;
2241         }
2242         /* we'll do an OFF -> ON transition: */
2243         curr->hardirqs_enabled = 1;
2244
2245         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2246                 return;
2247         if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
2248                 return;
2249         /*
2250          * We are going to turn hardirqs on, so set the
2251          * usage bit for all held locks:
2252          */
2253         if (!mark_held_locks(curr, HARDIRQ))
2254                 return;
2255         /*
2256          * If we have softirqs enabled, then set the usage
2257          * bit for all held locks. (disabled hardirqs prevented
2258          * this bit from being set before)
2259          */
2260         if (curr->softirqs_enabled)
2261                 if (!mark_held_locks(curr, SOFTIRQ))
2262                         return;
2263
2264         curr->hardirq_enable_ip = ip;
2265         curr->hardirq_enable_event = ++curr->irq_events;
2266         debug_atomic_inc(&hardirqs_on_events);
2267 }
2268 EXPORT_SYMBOL(trace_hardirqs_on_caller);
2269
2270 void trace_hardirqs_on(void)
2271 {
2272         trace_hardirqs_on_caller(CALLER_ADDR0);
2273 }
2274 EXPORT_SYMBOL(trace_hardirqs_on);
2275
2276 /*
2277  * Hardirqs were disabled:
2278  */
2279 void trace_hardirqs_off_caller(unsigned long ip)
2280 {
2281         struct task_struct *curr = current;
2282
2283         time_hardirqs_off(CALLER_ADDR0, ip);
2284
2285         if (unlikely(!debug_locks || current->lockdep_recursion))
2286                 return;
2287
2288         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2289                 return;
2290
2291         if (curr->hardirqs_enabled) {
2292                 /*
2293                  * We have done an ON -> OFF transition:
2294                  */
2295                 curr->hardirqs_enabled = 0;
2296                 curr->hardirq_disable_ip = ip;
2297                 curr->hardirq_disable_event = ++curr->irq_events;
2298                 debug_atomic_inc(&hardirqs_off_events);
2299         } else
2300                 debug_atomic_inc(&redundant_hardirqs_off);
2301 }
2302 EXPORT_SYMBOL(trace_hardirqs_off_caller);
2303
2304 void trace_hardirqs_off(void)
2305 {
2306         trace_hardirqs_off_caller(CALLER_ADDR0);
2307 }
2308 EXPORT_SYMBOL(trace_hardirqs_off);
2309
2310 /*
2311  * Softirqs will be enabled:
2312  */
2313 void trace_softirqs_on(unsigned long ip)
2314 {
2315         struct task_struct *curr = current;
2316
2317         if (unlikely(!debug_locks))
2318                 return;
2319
2320         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2321                 return;
2322
2323         if (curr->softirqs_enabled) {
2324                 debug_atomic_inc(&redundant_softirqs_on);
2325                 return;
2326         }
2327
2328         /*
2329          * We'll do an OFF -> ON transition:
2330          */
2331         curr->softirqs_enabled = 1;
2332         curr->softirq_enable_ip = ip;
2333         curr->softirq_enable_event = ++curr->irq_events;
2334         debug_atomic_inc(&softirqs_on_events);
2335         /*
2336          * We are going to turn softirqs on, so set the
2337          * usage bit for all held locks, if hardirqs are
2338          * enabled too:
2339          */
2340         if (curr->hardirqs_enabled)
2341                 mark_held_locks(curr, SOFTIRQ);
2342 }
2343
2344 /*
2345  * Softirqs were disabled:
2346  */
2347 void trace_softirqs_off(unsigned long ip)
2348 {
2349         struct task_struct *curr = current;
2350
2351         if (unlikely(!debug_locks))
2352                 return;
2353
2354         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2355                 return;
2356
2357         if (curr->softirqs_enabled) {
2358                 /*
2359                  * We have done an ON -> OFF transition:
2360                  */
2361                 curr->softirqs_enabled = 0;
2362                 curr->softirq_disable_ip = ip;
2363                 curr->softirq_disable_event = ++curr->irq_events;
2364                 debug_atomic_inc(&softirqs_off_events);
2365                 DEBUG_LOCKS_WARN_ON(!softirq_count());
2366         } else
2367                 debug_atomic_inc(&redundant_softirqs_off);
2368 }
2369
2370 static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
2371 {
2372         struct task_struct *curr = current;
2373
2374         if (unlikely(!debug_locks))
2375                 return;
2376
2377         /* no reclaim without waiting on it */
2378         if (!(gfp_mask & __GFP_WAIT))
2379                 return;
2380
2381         /* this guy won't enter reclaim */
2382         if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
2383                 return;
2384
2385         /* We're only interested __GFP_FS allocations for now */
2386         if (!(gfp_mask & __GFP_FS))
2387                 return;
2388
2389         if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
2390                 return;
2391
2392         mark_held_locks(curr, RECLAIM_FS);
2393 }
2394
2395 static void check_flags(unsigned long flags);
2396
2397 void lockdep_trace_alloc(gfp_t gfp_mask)
2398 {
2399         unsigned long flags;
2400
2401         if (unlikely(current->lockdep_recursion))
2402                 return;
2403
2404         raw_local_irq_save(flags);
2405         check_flags(flags);
2406         current->lockdep_recursion = 1;
2407         __lockdep_trace_alloc(gfp_mask, flags);
2408         current->lockdep_recursion = 0;
2409         raw_local_irq_restore(flags);
2410 }
2411
2412 static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
2413 {
2414         /*
2415          * If non-trylock use in a hardirq or softirq context, then
2416          * mark the lock as used in these contexts:
2417          */
2418         if (!hlock->trylock) {
2419                 if (hlock->read) {
2420                         if (curr->hardirq_context)
2421                                 if (!mark_lock(curr, hlock,
2422                                                 LOCK_USED_IN_HARDIRQ_READ))
2423                                         return 0;
2424                         if (curr->softirq_context)
2425                                 if (!mark_lock(curr, hlock,
2426                                                 LOCK_USED_IN_SOFTIRQ_READ))
2427                                         return 0;
2428                 } else {
2429                         if (curr->hardirq_context)
2430                                 if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
2431                                         return 0;
2432                         if (curr->softirq_context)
2433                                 if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
2434                                         return 0;
2435                 }
2436         }
2437         if (!hlock->hardirqs_off) {
2438                 if (hlock->read) {
2439                         if (!mark_lock(curr, hlock,
2440                                         LOCK_ENABLED_HARDIRQ_READ))
2441                                 return 0;
2442                         if (curr->softirqs_enabled)
2443                                 if (!mark_lock(curr, hlock,
2444                                                 LOCK_ENABLED_SOFTIRQ_READ))
2445                                         return 0;
2446                 } else {
2447                         if (!mark_lock(curr, hlock,
2448                                         LOCK_ENABLED_HARDIRQ))
2449                                 return 0;
2450                         if (curr->softirqs_enabled)
2451                                 if (!mark_lock(curr, hlock,
2452                                                 LOCK_ENABLED_SOFTIRQ))
2453                                         return 0;
2454                 }
2455         }
2456
2457         /*
2458          * We reuse the irq context infrastructure more broadly as a general
2459          * context checking code. This tests GFP_FS recursion (a lock taken
2460          * during reclaim for a GFP_FS allocation is held over a GFP_FS
2461          * allocation).
2462          */
2463         if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
2464                 if (hlock->read) {
2465                         if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
2466                                         return 0;
2467                 } else {
2468                         if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
2469                                         return 0;
2470                 }
2471         }
2472
2473         return 1;
2474 }
2475
2476 static int separate_irq_context(struct task_struct *curr,
2477                 struct held_lock *hlock)
2478 {
2479         unsigned int depth = curr->lockdep_depth;
2480
2481         /*
2482          * Keep track of points where we cross into an interrupt context:
2483          */
2484         hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
2485                                 curr->softirq_context;
2486         if (depth) {
2487                 struct held_lock *prev_hlock;
2488
2489                 prev_hlock = curr->held_locks + depth-1;
2490                 /*
2491                  * If we cross into another context, reset the
2492                  * hash key (this also prevents the checking and the
2493                  * adding of the dependency to 'prev'):
2494                  */
2495                 if (prev_hlock->irq_context != hlock->irq_context)
2496                         return 1;
2497         }
2498         return 0;
2499 }
2500
2501 #else
2502
2503 static inline
2504 int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2505                 enum lock_usage_bit new_bit)
2506 {
2507         WARN_ON(1);
2508         return 1;
2509 }
2510
2511 static inline int mark_irqflags(struct task_struct *curr,
2512                 struct held_lock *hlock)
2513 {
2514         return 1;
2515 }
2516
2517 static inline int separate_irq_context(struct task_struct *curr,
2518                 struct held_lock *hlock)
2519 {
2520         return 0;
2521 }
2522
2523 void lockdep_trace_alloc(gfp_t gfp_mask)
2524 {
2525 }
2526
2527 #endif
2528
2529 /*
2530  * Mark a lock with a usage bit, and validate the state transition:
2531  */
2532 static int mark_lock(struct task_struct *curr, struct held_lock *this,
2533                              enum lock_usage_bit new_bit)
2534 {
2535         unsigned int new_mask = 1 << new_bit, ret = 1;
2536
2537         /*
2538          * If already set then do not dirty the cacheline,
2539          * nor do any checks:
2540          */
2541         if (likely(hlock_class(this)->usage_mask & new_mask))
2542                 return 1;
2543
2544         if (!graph_lock())
2545                 return 0;
2546         /*
2547          * Make sure we didnt race:
2548          */
2549         if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
2550                 graph_unlock();
2551                 return 1;
2552         }
2553
2554         hlock_class(this)->usage_mask |= new_mask;
2555
2556         if (!save_trace(hlock_class(this)->usage_traces + new_bit))
2557                 return 0;
2558
2559         switch (new_bit) {
2560 #define LOCKDEP_STATE(__STATE)                  \
2561         case LOCK_USED_IN_##__STATE:            \
2562         case LOCK_USED_IN_##__STATE##_READ:     \
2563         case LOCK_ENABLED_##__STATE:            \
2564         case LOCK_ENABLED_##__STATE##_READ:
2565 #include "lockdep_states.h"
2566 #undef LOCKDEP_STATE
2567                 ret = mark_lock_irq(curr, this, new_bit);
2568                 if (!ret)
2569                         return 0;
2570                 break;
2571         case LOCK_USED:
2572                 debug_atomic_dec(&nr_unused_locks);
2573                 break;
2574         default:
2575                 if (!debug_locks_off_graph_unlock())
2576                         return 0;
2577                 WARN_ON(1);
2578                 return 0;
2579         }
2580
2581         graph_unlock();
2582
2583         /*
2584          * We must printk outside of the graph_lock:
2585          */
2586         if (ret == 2) {
2587                 printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
2588                 print_lock(this);
2589                 print_irqtrace_events(curr);
2590                 dump_stack();
2591         }
2592
2593         return ret;
2594 }
2595
2596 /*
2597  * Initialize a lock instance's lock-class mapping info:
2598  */
2599 void lockdep_init_map(struct lockdep_map *lock, const char *name,
2600                       struct lock_class_key *key, int subclass)
2601 {
2602         lock->class_cache = NULL;
2603 #ifdef CONFIG_LOCK_STAT
2604         lock->cpu = raw_smp_processor_id();
2605 #endif
2606
2607         if (DEBUG_LOCKS_WARN_ON(!name)) {
2608                 lock->name = "NULL";
2609                 return;
2610         }
2611
2612         lock->name = name;
2613
2614         if (DEBUG_LOCKS_WARN_ON(!key))
2615                 return;
2616         /*
2617          * Sanity check, the lock-class key must be persistent:
2618          */
2619         if (!static_obj(key)) {
2620                 printk("BUG: key %p not in .data!\n", key);
2621                 DEBUG_LOCKS_WARN_ON(1);
2622                 return;
2623         }
2624         lock->key = key;
2625
2626         if (unlikely(!debug_locks))
2627                 return;
2628
2629         if (subclass)
2630                 register_lock_class(lock, subclass, 1);
2631 }
2632 EXPORT_SYMBOL_GPL(lockdep_init_map);
2633
2634 /*
2635  * This gets called for every mutex_lock*()/spin_lock*() operation.
2636  * We maintain the dependency maps and validate the locking attempt:
2637  */
2638 static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
2639                           int trylock, int read, int check, int hardirqs_off,
2640                           struct lockdep_map *nest_lock, unsigned long ip)
2641 {
2642         struct task_struct *curr = current;
2643         struct lock_class *class = NULL;
2644         struct held_lock *hlock;
2645         unsigned int depth, id;
2646         int chain_head = 0;
2647         u64 chain_key;
2648
2649         if (!prove_locking)
2650                 check = 1;
2651
2652         if (unlikely(!debug_locks))
2653                 return 0;
2654
2655         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2656                 return 0;
2657
2658         if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
2659                 debug_locks_off();
2660                 printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
2661                 printk("turning off the locking correctness validator.\n");
2662                 dump_stack();
2663                 return 0;
2664         }
2665
2666         if (!subclass)
2667                 class = lock->class_cache;
2668         /*
2669          * Not cached yet or subclass?
2670          */
2671         if (unlikely(!class)) {
2672                 class = register_lock_class(lock, subclass, 0);
2673                 if (!class)
2674                         return 0;
2675         }
2676         debug_atomic_inc((atomic_t *)&class->ops);
2677         if (very_verbose(class)) {
2678                 printk("\nacquire class [%p] %s", class->key, class->name);
2679                 if (class->name_version > 1)
2680                         printk("#%d", class->name_version);
2681                 printk("\n");
2682                 dump_stack();
2683         }
2684
2685         /*
2686          * Add the lock to the list of currently held locks.
2687          * (we dont increase the depth just yet, up until the
2688          * dependency checks are done)
2689          */
2690         depth = curr->lockdep_depth;
2691         if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
2692                 return 0;
2693
2694         hlock = curr->held_locks + depth;
2695         if (DEBUG_LOCKS_WARN_ON(!class))
2696                 return 0;
2697         hlock->class_idx = class - lock_classes + 1;
2698         hlock->acquire_ip = ip;
2699         hlock->instance = lock;
2700         hlock->nest_lock = nest_lock;
2701         hlock->trylock = trylock;
2702         hlock->read = read;
2703         hlock->check = check;
2704         hlock->hardirqs_off = !!hardirqs_off;
2705 #ifdef CONFIG_LOCK_STAT
2706         hlock->waittime_stamp = 0;
2707         hlock->holdtime_stamp = sched_clock();
2708 #endif
2709
2710         if (check == 2 && !mark_irqflags(curr, hlock))
2711                 return 0;
2712
2713         /* mark it as used: */
2714         if (!mark_lock(curr, hlock, LOCK_USED))
2715                 return 0;
2716
2717         /*
2718          * Calculate the chain hash: it's the combined hash of all the
2719          * lock keys along the dependency chain. We save the hash value
2720          * at every step so that we can get the current hash easily
2721          * after unlock. The chain hash is then used to cache dependency
2722          * results.
2723          *
2724          * The 'key ID' is what is the most compact key value to drive
2725          * the hash, not class->key.
2726          */
2727         id = class - lock_classes;
2728         if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
2729                 return 0;
2730
2731         chain_key = curr->curr_chain_key;
2732         if (!depth) {
2733                 if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
2734                         return 0;
2735                 chain_head = 1;
2736         }
2737
2738         hlock->prev_chain_key = chain_key;
2739         if (separate_irq_context(curr, hlock)) {
2740                 chain_key = 0;
2741                 chain_head = 1;
2742         }
2743         chain_key = iterate_chain_key(chain_key, id);
2744
2745         if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
2746                 return 0;
2747
2748         curr->curr_chain_key = chain_key;
2749         curr->lockdep_depth++;
2750         check_chain_key(curr);
2751 #ifdef CONFIG_DEBUG_LOCKDEP
2752         if (unlikely(!debug_locks))
2753                 return 0;
2754 #endif
2755         if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
2756                 debug_locks_off();
2757                 printk("BUG: MAX_LOCK_DEPTH too low!\n");
2758                 printk("turning off the locking correctness validator.\n");
2759                 dump_stack();
2760                 return 0;
2761         }
2762
2763         if (unlikely(curr->lockdep_depth > max_lockdep_depth))
2764                 max_lockdep_depth = curr->lockdep_depth;
2765
2766         return 1;
2767 }
2768
2769 static int
2770 print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
2771                            unsigned long ip)
2772 {
2773         if (!debug_locks_off())
2774                 return 0;
2775         if (debug_locks_silent)
2776                 return 0;
2777
2778         printk("\n=====================================\n");
2779         printk(  "[ BUG: bad unlock balance detected! ]\n");
2780         printk(  "-------------------------------------\n");
2781         printk("%s/%d is trying to release lock (",
2782                 curr->comm, task_pid_nr(curr));
2783         print_lockdep_cache(lock);
2784         printk(") at:\n");
2785         print_ip_sym(ip);
2786         printk("but there are no more locks to release!\n");
2787         printk("\nother info that might help us debug this:\n");
2788         lockdep_print_held_locks(curr);
2789
2790         printk("\nstack backtrace:\n");
2791         dump_stack();
2792
2793         return 0;
2794 }
2795
2796 /*
2797  * Common debugging checks for both nested and non-nested unlock:
2798  */
2799 static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
2800                         unsigned long ip)
2801 {
2802         if (unlikely(!debug_locks))
2803                 return 0;
2804         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2805                 return 0;
2806
2807         if (curr->lockdep_depth <= 0)
2808                 return print_unlock_inbalance_bug(curr, lock, ip);
2809
2810         return 1;
2811 }
2812
2813 static int
2814 __lock_set_class(struct lockdep_map *lock, const char *name,
2815                  struct lock_class_key *key, unsigned int subclass,
2816                  unsigned long ip)
2817 {
2818         struct task_struct *curr = current;
2819         struct held_lock *hlock, *prev_hlock;
2820         struct lock_class *class;
2821         unsigned int depth;
2822         int i;
2823
2824         depth = curr->lockdep_depth;
2825         if (DEBUG_LOCKS_WARN_ON(!depth))
2826                 return 0;
2827
2828         prev_hlock = NULL;
2829         for (i = depth-1; i >= 0; i--) {
2830                 hlock = curr->held_locks + i;
2831                 /*
2832                  * We must not cross into another context:
2833                  */
2834                 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
2835                         break;
2836                 if (hlock->instance == lock)
2837                         goto found_it;
2838                 prev_hlock = hlock;
2839         }
2840         return print_unlock_inbalance_bug(curr, lock, ip);
2841
2842 found_it:
2843         lockdep_init_map(lock, name, key, 0);
2844         class = register_lock_class(lock, subclass, 0);
2845         hlock->class_idx = class - lock_classes + 1;
2846
2847         curr->lockdep_depth = i;
2848         curr->curr_chain_key = hlock->prev_chain_key;
2849
2850         for (; i < depth; i++) {
2851                 hlock = curr->held_locks + i;
2852                 if (!__lock_acquire(hlock->instance,
2853                         hlock_class(hlock)->subclass, hlock->trylock,
2854                                 hlock->read, hlock->check, hlock->hardirqs_off,
2855                                 hlock->nest_lock, hlock->acquire_ip))
2856                         return 0;
2857         }
2858
2859         if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
2860                 return 0;
2861         return 1;
2862 }
2863
2864 /*
2865  * Remove the lock to the list of currently held locks in a
2866  * potentially non-nested (out of order) manner. This is a
2867  * relatively rare operation, as all the unlock APIs default
2868  * to nested mode (which uses lock_release()):
2869  */
2870 static int
2871 lock_release_non_nested(struct task_struct *curr,
2872                         struct lockdep_map *lock, unsigned long ip)
2873 {
2874         struct held_lock *hlock, *prev_hlock;
2875         unsigned int depth;
2876         int i;
2877
2878         /*
2879          * Check whether the lock exists in the current stack
2880          * of held locks:
2881          */
2882         depth = curr->lockdep_depth;
2883         if (DEBUG_LOCKS_WARN_ON(!depth))
2884                 return 0;
2885
2886         prev_hlock = NULL;
2887         for (i = depth-1; i >= 0; i--) {
2888                 hlock = curr->held_locks + i;
2889                 /*
2890                  * We must not cross into another context:
2891                  */
2892                 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
2893                         break;
2894                 if (hlock->instance == lock)
2895                         goto found_it;
2896                 prev_hlock = hlock;
2897         }
2898         return print_unlock_inbalance_bug(curr, lock, ip);
2899
2900 found_it:
2901         lock_release_holdtime(hlock);
2902
2903         /*
2904          * We have the right lock to unlock, 'hlock' points to it.
2905          * Now we remove it from the stack, and add back the other
2906          * entries (if any), recalculating the hash along the way:
2907          */
2908         curr->lockdep_depth = i;
2909         curr->curr_chain_key = hlock->prev_chain_key;
2910
2911         for (i++; i < depth; i++) {
2912                 hlock = curr->held_locks + i;
2913                 if (!__lock_acquire(hlock->instance,
2914                         hlock_class(hlock)->subclass, hlock->trylock,
2915                                 hlock->read, hlock->check, hlock->hardirqs_off,
2916                                 hlock->nest_lock, hlock->acquire_ip))
2917                         return 0;
2918         }
2919
2920         if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
2921                 return 0;
2922         return 1;
2923 }
2924
2925 /*
2926  * Remove the lock to the list of currently held locks - this gets
2927  * called on mutex_unlock()/spin_unlock*() (or on a failed
2928  * mutex_lock_interruptible()). This is done for unlocks that nest
2929  * perfectly. (i.e. the current top of the lock-stack is unlocked)
2930  */
2931 static int lock_release_nested(struct task_struct *curr,
2932                                struct lockdep_map *lock, unsigned long ip)
2933 {
2934         struct held_lock *hlock;
2935         unsigned int depth;
2936
2937         /*
2938          * Pop off the top of the lock stack:
2939          */
2940         depth = curr->lockdep_depth - 1;
2941         hlock = curr->held_locks + depth;
2942
2943         /*
2944          * Is the unlock non-nested:
2945          */
2946         if (hlock->instance != lock)
2947                 return lock_release_non_nested(curr, lock, ip);
2948         curr->lockdep_depth--;
2949
2950         if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
2951                 return 0;
2952
2953         curr->curr_chain_key = hlock->prev_chain_key;
2954
2955         lock_release_holdtime(hlock);
2956
2957 #ifdef CONFIG_DEBUG_LOCKDEP
2958         hlock->prev_chain_key = 0;
2959         hlock->class_idx = 0;
2960         hlock->acquire_ip = 0;
2961         hlock->irq_context = 0;
2962 #endif
2963         return 1;
2964 }
2965
2966 /*
2967  * Remove the lock to the list of currently held locks - this gets
2968  * called on mutex_unlock()/spin_unlock*() (or on a failed
2969  * mutex_lock_interruptible()). This is done for unlocks that nest
2970  * perfectly. (i.e. the current top of the lock-stack is unlocked)
2971  */
2972 static void
2973 __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
2974 {
2975         struct task_struct *curr = current;
2976
2977         if (!check_unlock(curr, lock, ip))
2978                 return;
2979
2980         if (nested) {
2981                 if (!lock_release_nested(curr, lock, ip))
2982                         return;
2983         } else {
2984                 if (!lock_release_non_nested(curr, lock, ip))
2985                         return;
2986         }
2987
2988         check_chain_key(curr);
2989 }
2990
2991 /*
2992  * Check whether we follow the irq-flags state precisely:
2993  */
2994 static void check_flags(unsigned long flags)
2995 {
2996 #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
2997     defined(CONFIG_TRACE_IRQFLAGS)
2998         if (!debug_locks)
2999                 return;
3000
3001         if (irqs_disabled_flags(flags)) {
3002                 if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
3003                         printk("possible reason: unannotated irqs-off.\n");
3004                 }
3005         } else {
3006                 if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
3007                         printk("possible reason: unannotated irqs-on.\n");
3008                 }
3009         }
3010
3011         /*
3012          * We dont accurately track softirq state in e.g.
3013          * hardirq contexts (such as on 4KSTACKS), so only
3014          * check if not in hardirq contexts:
3015          */
3016         if (!hardirq_count()) {
3017                 if (softirq_count())
3018                         DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
3019                 else
3020                         DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
3021         }
3022
3023         if (!debug_locks)
3024                 print_irqtrace_events(current);
3025 #endif
3026 }
3027
3028 void lock_set_class(struct lockdep_map *lock, const char *name,
3029                     struct lock_class_key *key, unsigned int subclass,
3030                     unsigned long ip)
3031 {
3032         unsigned long flags;
3033
3034         if (unlikely(current->lockdep_recursion))
3035                 return;
3036
3037         raw_local_irq_save(flags);
3038         current->lockdep_recursion = 1;
3039         check_flags(flags);
3040         if (__lock_set_class(lock, name, key, subclass, ip))
3041                 check_chain_key(current);
3042         current->lockdep_recursion = 0;
3043         raw_local_irq_restore(flags);
3044 }
3045 EXPORT_SYMBOL_GPL(lock_set_class);
3046
3047 /*
3048  * We are not always called with irqs disabled - do that here,
3049  * and also avoid lockdep recursion:
3050  */
3051 void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
3052                           int trylock, int read, int check,
3053                           struct lockdep_map *nest_lock, unsigned long ip)
3054 {
3055         unsigned long flags;
3056
3057         trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
3058
3059         if (unlikely(current->lockdep_recursion))
3060                 return;
3061
3062         raw_local_irq_save(flags);
3063         check_flags(flags);
3064
3065         current->lockdep_recursion = 1;
3066         __lock_acquire(lock, subclass, trylock, read, check,
3067                        irqs_disabled_flags(flags), nest_lock, ip);
3068         current->lockdep_recursion = 0;
3069         raw_local_irq_restore(flags);
3070 }
3071 EXPORT_SYMBOL_GPL(lock_acquire);
3072
3073 void lock_release(struct lockdep_map *lock, int nested,
3074                           unsigned long ip)
3075 {
3076         unsigned long flags;
3077
3078         trace_lock_release(lock, nested, ip);
3079
3080         if (unlikely(current->lockdep_recursion))
3081                 return;
3082
3083         raw_local_irq_save(flags);
3084         check_flags(flags);
3085         current->lockdep_recursion = 1;
3086         __lock_release(lock, nested, ip);
3087         current->lockdep_recursion = 0;
3088         raw_local_irq_restore(flags);
3089 }
3090 EXPORT_SYMBOL_GPL(lock_release);
3091
3092 void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
3093 {
3094         current->lockdep_reclaim_gfp = gfp_mask;
3095 }
3096
3097 void lockdep_clear_current_reclaim_state(void)
3098 {
3099         current->lockdep_reclaim_gfp = 0;
3100 }
3101
3102 #ifdef CONFIG_LOCK_STAT
3103 static int
3104 print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
3105                            unsigned long ip)
3106 {
3107         if (!debug_locks_off())
3108                 return 0;
3109         if (debug_locks_silent)
3110                 return 0;
3111
3112         printk("\n=================================\n");
3113         printk(  "[ BUG: bad contention detected! ]\n");
3114         printk(  "---------------------------------\n");
3115         printk("%s/%d is trying to contend lock (",
3116                 curr->comm, task_pid_nr(curr));
3117         print_lockdep_cache(lock);
3118         printk(") at:\n");
3119         print_ip_sym(ip);
3120         printk("but there are no locks held!\n");
3121         printk("\nother info that might help us debug this:\n");
3122         lockdep_print_held_locks(curr);
3123
3124         printk("\nstack backtrace:\n");
3125         dump_stack();
3126
3127         return 0;
3128 }
3129
3130 static void
3131 __lock_contended(struct lockdep_map *lock, unsigned long ip)
3132 {
3133         struct task_struct *curr = current;
3134         struct held_lock *hlock, *prev_hlock;
3135         struct lock_class_stats *stats;
3136         unsigned int depth;
3137         int i, contention_point, contending_point;
3138
3139         depth = curr->lockdep_depth;
3140         if (DEBUG_LOCKS_WARN_ON(!depth))
3141                 return;
3142
3143         prev_hlock = NULL;
3144         for (i = depth-1; i >= 0; i--) {
3145                 hlock = curr->held_locks + i;
3146                 /*
3147                  * We must not cross into another context:
3148                  */
3149                 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3150                         break;
3151                 if (hlock->instance == lock)
3152                         goto found_it;
3153                 prev_hlock = hlock;
3154         }
3155         print_lock_contention_bug(curr, lock, ip);
3156         return;
3157
3158 found_it:
3159         hlock->waittime_stamp = sched_clock();
3160
3161         contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
3162         contending_point = lock_point(hlock_class(hlock)->contending_point,
3163                                       lock->ip);
3164
3165         stats = get_lock_stats(hlock_class(hlock));
3166         if (contention_point < LOCKSTAT_POINTS)
3167                 stats->contention_point[contention_point]++;
3168         if (contending_point < LOCKSTAT_POINTS)
3169                 stats->contending_point[contending_point]++;
3170         if (lock->cpu != smp_processor_id())
3171                 stats->bounces[bounce_contended + !!hlock->read]++;
3172         put_lock_stats(stats);
3173 }
3174
3175 static void
3176 __lock_acquired(struct lockdep_map *lock, unsigned long ip)
3177 {
3178         struct task_struct *curr = current;
3179         struct held_lock *hlock, *prev_hlock;
3180         struct lock_class_stats *stats;
3181         unsigned int depth;
3182         u64 now;
3183         s64 waittime = 0;
3184         int i, cpu;
3185
3186         depth = curr->lockdep_depth;
3187         if (DEBUG_LOCKS_WARN_ON(!depth))
3188                 return;
3189
3190         prev_hlock = NULL;
3191         for (i = depth-1; i >= 0; i--) {
3192                 hlock = curr->held_locks + i;
3193                 /*
3194                  * We must not cross into another context:
3195                  */
3196                 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3197                         break;
3198                 if (hlock->instance == lock)
3199                         goto found_it;
3200                 prev_hlock = hlock;
3201         }
3202         print_lock_contention_bug(curr, lock, _RET_IP_);
3203         return;
3204
3205 found_it:
3206         cpu = smp_processor_id();
3207         if (hlock->waittime_stamp) {
3208                 now = sched_clock();
3209                 waittime = now - hlock->waittime_stamp;
3210                 hlock->holdtime_stamp = now;
3211         }
3212
3213         trace_lock_acquired(lock, ip, waittime);
3214
3215         stats = get_lock_stats(hlock_class(hlock));
3216         if (waittime) {
3217                 if (hlock->read)
3218                         lock_time_inc(&stats->read_waittime, waittime);
3219                 else
3220                         lock_time_inc(&stats->write_waittime, waittime);
3221         }
3222         if (lock->cpu != cpu)
3223                 stats->bounces[bounce_acquired + !!hlock->read]++;
3224         put_lock_stats(stats);
3225
3226         lock->cpu = cpu;
3227         lock->ip = ip;
3228 }
3229
3230 void lock_contended(struct lockdep_map *lock, unsigned long ip)
3231 {
3232         unsigned long flags;
3233
3234         trace_lock_contended(lock, ip);
3235
3236         if (unlikely(!lock_stat))
3237                 return;
3238
3239         if (unlikely(current->lockdep_recursion))
3240                 return;
3241
3242         raw_local_irq_save(flags);
3243         check_flags(flags);
3244         current->lockdep_recursion = 1;
3245         __lock_contended(lock, ip);
3246         current->lockdep_recursion = 0;
3247         raw_local_irq_restore(flags);
3248 }
3249 EXPORT_SYMBOL_GPL(lock_contended);
3250
3251 void lock_acquired(struct lockdep_map *lock, unsigned long ip)
3252 {
3253         unsigned long flags;
3254
3255         if (unlikely(!lock_stat))
3256                 return;
3257
3258         if (unlikely(current->lockdep_recursion))
3259                 return;
3260
3261         raw_local_irq_save(flags);
3262         check_flags(flags);
3263         current->lockdep_recursion = 1;
3264         __lock_acquired(lock, ip);
3265         current->lockdep_recursion = 0;
3266         raw_local_irq_restore(flags);
3267 }
3268 EXPORT_SYMBOL_GPL(lock_acquired);
3269 #endif
3270
3271 /*
3272  * Used by the testsuite, sanitize the validator state
3273  * after a simulated failure:
3274  */
3275
3276 void lockdep_reset(void)
3277 {
3278         unsigned long flags;
3279         int i;
3280
3281         raw_local_irq_save(flags);
3282         current->curr_chain_key = 0;
3283         current->lockdep_depth = 0;
3284         current->lockdep_recursion = 0;
3285         memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
3286         nr_hardirq_chains = 0;
3287         nr_softirq_chains = 0;
3288         nr_process_chains = 0;
3289         debug_locks = 1;
3290         for (i = 0; i < CHAINHASH_SIZE; i++)
3291                 INIT_LIST_HEAD(chainhash_table + i);
3292         raw_local_irq_restore(flags);
3293 }
3294
3295 static void zap_class(struct lock_class *class)
3296 {
3297         int i;
3298
3299         /*
3300          * Remove all dependencies this lock is
3301          * involved in:
3302          */
3303         for (i = 0; i < nr_list_entries; i++) {
3304                 if (list_entries[i].class == class)
3305                         list_del_rcu(&list_entries[i].entry);
3306         }
3307         /*
3308          * Unhash the class and remove it from the all_lock_classes list:
3309          */
3310         list_del_rcu(&class->hash_entry);
3311         list_del_rcu(&class->lock_entry);
3312
3313         class->key = NULL;
3314 }
3315
3316 static inline int within(const void *addr, void *start, unsigned long size)
3317 {
3318         return addr >= start && addr < start + size;
3319 }
3320
3321 void lockdep_free_key_range(void *start, unsigned long size)
3322 {
3323         struct lock_class *class, *next;
3324         struct list_head *head;
3325         unsigned long flags;
3326         int i;
3327         int locked;
3328
3329         raw_local_irq_save(flags);
3330         locked = graph_lock();
3331
3332         /*
3333          * Unhash all classes that were created by this module:
3334          */
3335         for (i = 0; i < CLASSHASH_SIZE; i++) {
3336                 head = classhash_table + i;
3337                 if (list_empty(head))
3338                         continue;
3339                 list_for_each_entry_safe(class, next, head, hash_entry) {
3340                         if (within(class->key, start, size))
3341                                 zap_class(class);
3342                         else if (within(class->name, start, size))
3343                                 zap_class(class);
3344                 }
3345         }
3346
3347         if (locked)
3348                 graph_unlock();
3349         raw_local_irq_restore(flags);
3350 }
3351
3352 void lockdep_reset_lock(struct lockdep_map *lock)
3353 {
3354         struct lock_class *class, *next;
3355         struct list_head *head;
3356         unsigned long flags;
3357         int i, j;
3358         int locked;
3359
3360         raw_local_irq_save(flags);
3361
3362         /*
3363          * Remove all classes this lock might have:
3364          */
3365         for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
3366                 /*
3367                  * If the class exists we look it up and zap it:
3368                  */
3369                 class = look_up_lock_class(lock, j);
3370                 if (class)
3371                         zap_class(class);
3372         }
3373         /*
3374          * Debug check: in the end all mapped classes should
3375          * be gone.
3376          */
3377         locked = graph_lock();
3378         for (i = 0; i < CLASSHASH_SIZE; i++) {
3379                 head = classhash_table + i;
3380                 if (list_empty(head))
3381                         continue;
3382                 list_for_each_entry_safe(class, next, head, hash_entry) {
3383                         if (unlikely(class == lock->class_cache)) {
3384                                 if (debug_locks_off_graph_unlock())
3385                                         WARN_ON(1);
3386                                 goto out_restore;
3387                         }
3388                 }
3389         }
3390         if (locked)
3391                 graph_unlock();
3392
3393 out_restore:
3394         raw_local_irq_restore(flags);
3395 }
3396
3397 void lockdep_init(void)
3398 {
3399         int i;
3400
3401         /*
3402          * Some architectures have their own start_kernel()
3403          * code which calls lockdep_init(), while we also
3404          * call lockdep_init() from the start_kernel() itself,
3405          * and we want to initialize the hashes only once:
3406          */
3407         if (lockdep_initialized)
3408                 return;
3409
3410         for (i = 0; i < CLASSHASH_SIZE; i++)
3411                 INIT_LIST_HEAD(classhash_table + i);
3412
3413         for (i = 0; i < CHAINHASH_SIZE; i++)
3414                 INIT_LIST_HEAD(chainhash_table + i);
3415
3416         lockdep_initialized = 1;
3417 }
3418
3419 void __init lockdep_info(void)
3420 {
3421         printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
3422
3423         printk("... MAX_LOCKDEP_SUBCLASSES:  %lu\n", MAX_LOCKDEP_SUBCLASSES);
3424         printk("... MAX_LOCK_DEPTH:          %lu\n", MAX_LOCK_DEPTH);
3425         printk("... MAX_LOCKDEP_KEYS:        %lu\n", MAX_LOCKDEP_KEYS);
3426         printk("... CLASSHASH_SIZE:          %lu\n", CLASSHASH_SIZE);
3427         printk("... MAX_LOCKDEP_ENTRIES:     %lu\n", MAX_LOCKDEP_ENTRIES);
3428         printk("... MAX_LOCKDEP_CHAINS:      %lu\n", MAX_LOCKDEP_CHAINS);
3429         printk("... CHAINHASH_SIZE:          %lu\n", CHAINHASH_SIZE);
3430
3431         printk(" memory used by lock dependency info: %lu kB\n",
3432                 (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
3433                 sizeof(struct list_head) * CLASSHASH_SIZE +
3434                 sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
3435                 sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
3436                 sizeof(struct list_head) * CHAINHASH_SIZE) / 1024
3437 #ifdef CONFIG_PROVE_LOCKING
3438                 + sizeof(struct circular_queue) + sizeof(bfs_accessed)
3439 #endif
3440                 );
3441
3442         printk(" per task-struct memory footprint: %lu bytes\n",
3443                 sizeof(struct held_lock) * MAX_LOCK_DEPTH);
3444
3445 #ifdef CONFIG_DEBUG_LOCKDEP
3446         if (lockdep_init_error) {
3447                 printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
3448                 printk("Call stack leading to lockdep invocation was:\n");
3449                 print_stack_trace(&lockdep_init_trace, 0);
3450         }
3451 #endif
3452 }
3453
3454 static void
3455 print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
3456                      const void *mem_to, struct held_lock *hlock)
3457 {
3458         if (!debug_locks_off())
3459                 return;
3460         if (debug_locks_silent)
3461                 return;
3462
3463         printk("\n=========================\n");
3464         printk(  "[ BUG: held lock freed! ]\n");
3465         printk(  "-------------------------\n");
3466         printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
3467                 curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
3468         print_lock(hlock);
3469         lockdep_print_held_locks(curr);
3470
3471         printk("\nstack backtrace:\n");
3472         dump_stack();
3473 }
3474
3475 static inline int not_in_range(const void* mem_from, unsigned long mem_len,
3476                                 const void* lock_from, unsigned long lock_len)
3477 {
3478         return lock_from + lock_len <= mem_from ||
3479                 mem_from + mem_len <= lock_from;
3480 }
3481
3482 /*
3483  * Called when kernel memory is freed (or unmapped), or if a lock
3484  * is destroyed or reinitialized - this code checks whether there is
3485  * any held lock in the memory range of <from> to <to>:
3486  */
3487 void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
3488 {
3489         struct task_struct *curr = current;
3490         struct held_lock *hlock;
3491         unsigned long flags;
3492         int i;
3493
3494         if (unlikely(!debug_locks))
3495                 return;
3496
3497         local_irq_save(flags);
3498         for (i = 0; i < curr->lockdep_depth; i++) {
3499                 hlock = curr->held_locks + i;
3500
3501                 if (not_in_range(mem_from, mem_len, hlock->instance,
3502                                         sizeof(*hlock->instance)))
3503                         continue;
3504
3505                 print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
3506                 break;
3507         }
3508         local_irq_restore(flags);
3509 }
3510 EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
3511
3512 static void print_held_locks_bug(struct task_struct *curr)
3513 {
3514         if (!debug_locks_off())
3515                 return;
3516         if (debug_locks_silent)
3517                 return;
3518
3519         printk("\n=====================================\n");
3520         printk(  "[ BUG: lock held at task exit time! ]\n");
3521         printk(  "-------------------------------------\n");
3522         printk("%s/%d is exiting with locks still held!\n",
3523                 curr->comm, task_pid_nr(curr));
3524         lockdep_print_held_locks(curr);
3525
3526         printk("\nstack backtrace:\n");
3527         dump_stack();
3528 }
3529
3530 void debug_check_no_locks_held(struct task_struct *task)
3531 {
3532         if (unlikely(task->lockdep_depth > 0))
3533                 print_held_locks_bug(task);
3534 }
3535
3536 void debug_show_all_locks(void)
3537 {
3538         struct task_struct *g, *p;
3539         int count = 10;
3540         int unlock = 1;
3541
3542         if (unlikely(!debug_locks)) {
3543                 printk("INFO: lockdep is turned off.\n");
3544                 return;
3545         }
3546         printk("\nShowing all locks held in the system:\n");
3547
3548         /*
3549          * Here we try to get the tasklist_lock as hard as possible,
3550          * if not successful after 2 seconds we ignore it (but keep
3551          * trying). This is to enable a debug printout even if a
3552          * tasklist_lock-holding task deadlocks or crashes.
3553          */
3554 retry:
3555         if (!read_trylock(&tasklist_lock)) {
3556                 if (count == 10)
3557                         printk("hm, tasklist_lock locked, retrying... ");
3558                 if (count) {
3559                         count--;
3560                         printk(" #%d", 10-count);
3561                         mdelay(200);
3562                         goto retry;
3563                 }
3564                 printk(" ignoring it.\n");
3565                 unlock = 0;
3566         } else {
3567                 if (count != 10)
3568                         printk(KERN_CONT " locked it.\n");
3569         }
3570
3571         do_each_thread(g, p) {
3572                 /*
3573                  * It's not reliable to print a task's held locks
3574                  * if it's not sleeping (or if it's not the current
3575                  * task):
3576                  */
3577                 if (p->state == TASK_RUNNING && p != current)
3578                         continue;
3579                 if (p->lockdep_depth)
3580                         lockdep_print_held_locks(p);
3581                 if (!unlock)
3582                         if (read_trylock(&tasklist_lock))
3583                                 unlock = 1;
3584         } while_each_thread(g, p);
3585
3586         printk("\n");
3587         printk("=============================================\n\n");
3588
3589         if (unlock)
3590                 read_unlock(&tasklist_lock);
3591 }
3592 EXPORT_SYMBOL_GPL(debug_show_all_locks);
3593
3594 /*
3595  * Careful: only use this function if you are sure that
3596  * the task cannot run in parallel!
3597  */
3598 void __debug_show_held_locks(struct task_struct *task)
3599 {
3600         if (unlikely(!debug_locks)) {
3601                 printk("INFO: lockdep is turned off.\n");
3602                 return;
3603         }
3604         lockdep_print_held_locks(task);
3605 }
3606 EXPORT_SYMBOL_GPL(__debug_show_held_locks);
3607
3608 void debug_show_held_locks(struct task_struct *task)
3609 {
3610                 __debug_show_held_locks(task);
3611 }
3612 EXPORT_SYMBOL_GPL(debug_show_held_locks);
3613
3614 void lockdep_sys_exit(void)
3615 {
3616         struct task_struct *curr = current;
3617
3618         if (unlikely(curr->lockdep_depth)) {
3619                 if (!debug_locks_off())
3620                         return;
3621                 printk("\n================================================\n");
3622                 printk(  "[ BUG: lock held when returning to user space! ]\n");
3623                 printk(  "------------------------------------------------\n");
3624                 printk("%s/%d is leaving the kernel with locks still held!\n",
3625                                 curr->comm, curr->pid);
3626                 lockdep_print_held_locks(curr);
3627         }
3628 }