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26
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 <linux/gfp.h>
47#include <linux/kmemcheck.h>
48
49#include <asm/sections.h>
50
51#include "lockdep_internals.h"
52
53#define CREATE_TRACE_POINTS
54#include <trace/events/lock.h>
55
56#ifdef CONFIG_PROVE_LOCKING
57int prove_locking = 1;
58module_param(prove_locking, int, 0644);
59#else
60#define prove_locking 0
61#endif
62
63#ifdef CONFIG_LOCK_STAT
64int lock_stat = 1;
65module_param(lock_stat, int, 0644);
66#else
67#define lock_stat 0
68#endif
69
70
71
72
73
74
75
76
77
78static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
79
80static int graph_lock(void)
81{
82 arch_spin_lock(&lockdep_lock);
83
84
85
86
87
88
89 if (!debug_locks) {
90 arch_spin_unlock(&lockdep_lock);
91 return 0;
92 }
93
94 current->lockdep_recursion++;
95 return 1;
96}
97
98static inline int graph_unlock(void)
99{
100 if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) {
101
102
103
104
105 return DEBUG_LOCKS_WARN_ON(1);
106 }
107
108 current->lockdep_recursion--;
109 arch_spin_unlock(&lockdep_lock);
110 return 0;
111}
112
113
114
115
116
117static inline int debug_locks_off_graph_unlock(void)
118{
119 int ret = debug_locks_off();
120
121 arch_spin_unlock(&lockdep_lock);
122
123 return ret;
124}
125
126static int lockdep_initialized;
127
128unsigned long nr_list_entries;
129static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
130
131
132
133
134
135
136
137unsigned long nr_lock_classes;
138static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
139
140static inline struct lock_class *hlock_class(struct held_lock *hlock)
141{
142 if (!hlock->class_idx) {
143
144
145
146 DEBUG_LOCKS_WARN_ON(1);
147 return NULL;
148 }
149 return lock_classes + hlock->class_idx - 1;
150}
151
152#ifdef CONFIG_LOCK_STAT
153static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS],
154 cpu_lock_stats);
155
156static inline u64 lockstat_clock(void)
157{
158 return local_clock();
159}
160
161static int lock_point(unsigned long points[], unsigned long ip)
162{
163 int i;
164
165 for (i = 0; i < LOCKSTAT_POINTS; i++) {
166 if (points[i] == 0) {
167 points[i] = ip;
168 break;
169 }
170 if (points[i] == ip)
171 break;
172 }
173
174 return i;
175}
176
177static void lock_time_inc(struct lock_time *lt, u64 time)
178{
179 if (time > lt->max)
180 lt->max = time;
181
182 if (time < lt->min || !lt->nr)
183 lt->min = time;
184
185 lt->total += time;
186 lt->nr++;
187}
188
189static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
190{
191 if (!src->nr)
192 return;
193
194 if (src->max > dst->max)
195 dst->max = src->max;
196
197 if (src->min < dst->min || !dst->nr)
198 dst->min = src->min;
199
200 dst->total += src->total;
201 dst->nr += src->nr;
202}
203
204struct lock_class_stats lock_stats(struct lock_class *class)
205{
206 struct lock_class_stats stats;
207 int cpu, i;
208
209 memset(&stats, 0, sizeof(struct lock_class_stats));
210 for_each_possible_cpu(cpu) {
211 struct lock_class_stats *pcs =
212 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
213
214 for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
215 stats.contention_point[i] += pcs->contention_point[i];
216
217 for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
218 stats.contending_point[i] += pcs->contending_point[i];
219
220 lock_time_add(&pcs->read_waittime, &stats.read_waittime);
221 lock_time_add(&pcs->write_waittime, &stats.write_waittime);
222
223 lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
224 lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
225
226 for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
227 stats.bounces[i] += pcs->bounces[i];
228 }
229
230 return stats;
231}
232
233void clear_lock_stats(struct lock_class *class)
234{
235 int cpu;
236
237 for_each_possible_cpu(cpu) {
238 struct lock_class_stats *cpu_stats =
239 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
240
241 memset(cpu_stats, 0, sizeof(struct lock_class_stats));
242 }
243 memset(class->contention_point, 0, sizeof(class->contention_point));
244 memset(class->contending_point, 0, sizeof(class->contending_point));
245}
246
247static struct lock_class_stats *get_lock_stats(struct lock_class *class)
248{
249 return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
250}
251
252static void put_lock_stats(struct lock_class_stats *stats)
253{
254 put_cpu_var(cpu_lock_stats);
255}
256
257static void lock_release_holdtime(struct held_lock *hlock)
258{
259 struct lock_class_stats *stats;
260 u64 holdtime;
261
262 if (!lock_stat)
263 return;
264
265 holdtime = lockstat_clock() - hlock->holdtime_stamp;
266
267 stats = get_lock_stats(hlock_class(hlock));
268 if (hlock->read)
269 lock_time_inc(&stats->read_holdtime, holdtime);
270 else
271 lock_time_inc(&stats->write_holdtime, holdtime);
272 put_lock_stats(stats);
273}
274#else
275static inline void lock_release_holdtime(struct held_lock *hlock)
276{
277}
278#endif
279
280
281
282
283
284
285LIST_HEAD(all_lock_classes);
286
287
288
289
290#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
291#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
292#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
293#define classhashentry(key) (classhash_table + __classhashfn((key)))
294
295static struct list_head classhash_table[CLASSHASH_SIZE];
296
297
298
299
300
301#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
302#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
303#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
304#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
305
306static struct list_head chainhash_table[CHAINHASH_SIZE];
307
308
309
310
311
312
313
314#define iterate_chain_key(key1, key2) \
315 (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
316 ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
317 (key2))
318
319void lockdep_off(void)
320{
321 current->lockdep_recursion++;
322}
323EXPORT_SYMBOL(lockdep_off);
324
325void lockdep_on(void)
326{
327 current->lockdep_recursion--;
328}
329EXPORT_SYMBOL(lockdep_on);
330
331
332
333
334
335#define VERBOSE 0
336#define VERY_VERBOSE 0
337
338#if VERBOSE
339# define HARDIRQ_VERBOSE 1
340# define SOFTIRQ_VERBOSE 1
341# define RECLAIM_VERBOSE 1
342#else
343# define HARDIRQ_VERBOSE 0
344# define SOFTIRQ_VERBOSE 0
345# define RECLAIM_VERBOSE 0
346#endif
347
348#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
349
350
351
352static int class_filter(struct lock_class *class)
353{
354#if 0
355
356 if (class->name_version == 1 &&
357 !strcmp(class->name, "lockname"))
358 return 1;
359 if (class->name_version == 1 &&
360 !strcmp(class->name, "&struct->lockfield"))
361 return 1;
362#endif
363
364 return 0;
365}
366#endif
367
368static int verbose(struct lock_class *class)
369{
370#if VERBOSE
371 return class_filter(class);
372#endif
373 return 0;
374}
375
376
377
378
379
380unsigned long nr_stack_trace_entries;
381static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
382
383static void print_lockdep_off(const char *bug_msg)
384{
385 printk(KERN_DEBUG "%s\n", bug_msg);
386 printk(KERN_DEBUG "turning off the locking correctness validator.\n");
387 printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
388}
389
390static int save_trace(struct stack_trace *trace)
391{
392 trace->nr_entries = 0;
393 trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
394 trace->entries = stack_trace + nr_stack_trace_entries;
395
396 trace->skip = 3;
397
398 save_stack_trace(trace);
399
400
401
402
403
404
405
406
407 if (trace->nr_entries != 0 &&
408 trace->entries[trace->nr_entries-1] == ULONG_MAX)
409 trace->nr_entries--;
410
411 trace->max_entries = trace->nr_entries;
412
413 nr_stack_trace_entries += trace->nr_entries;
414
415 if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
416 if (!debug_locks_off_graph_unlock())
417 return 0;
418
419 print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
420 dump_stack();
421
422 return 0;
423 }
424
425 return 1;
426}
427
428unsigned int nr_hardirq_chains;
429unsigned int nr_softirq_chains;
430unsigned int nr_process_chains;
431unsigned int max_lockdep_depth;
432
433#ifdef CONFIG_DEBUG_LOCKDEP
434
435
436
437
438
439static int lockdep_init_error;
440static const char *lock_init_error;
441static unsigned long lockdep_init_trace_data[20];
442static struct stack_trace lockdep_init_trace = {
443 .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
444 .entries = lockdep_init_trace_data,
445};
446
447
448
449
450DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
451#endif
452
453
454
455
456
457#define __USAGE(__STATE) \
458 [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
459 [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
460 [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
461 [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
462
463static const char *usage_str[] =
464{
465#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
466#include "lockdep_states.h"
467#undef LOCKDEP_STATE
468 [LOCK_USED] = "INITIAL USE",
469};
470
471const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
472{
473 return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
474}
475
476static inline unsigned long lock_flag(enum lock_usage_bit bit)
477{
478 return 1UL << bit;
479}
480
481static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
482{
483 char c = '.';
484
485 if (class->usage_mask & lock_flag(bit + 2))
486 c = '+';
487 if (class->usage_mask & lock_flag(bit)) {
488 c = '-';
489 if (class->usage_mask & lock_flag(bit + 2))
490 c = '?';
491 }
492
493 return c;
494}
495
496void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
497{
498 int i = 0;
499
500#define LOCKDEP_STATE(__STATE) \
501 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
502 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
503#include "lockdep_states.h"
504#undef LOCKDEP_STATE
505
506 usage[i] = '\0';
507}
508
509static void __print_lock_name(struct lock_class *class)
510{
511 char str[KSYM_NAME_LEN];
512 const char *name;
513
514 name = class->name;
515 if (!name) {
516 name = __get_key_name(class->key, str);
517 printk("%s", name);
518 } else {
519 printk("%s", name);
520 if (class->name_version > 1)
521 printk("#%d", class->name_version);
522 if (class->subclass)
523 printk("/%d", class->subclass);
524 }
525}
526
527static void print_lock_name(struct lock_class *class)
528{
529 char usage[LOCK_USAGE_CHARS];
530
531 get_usage_chars(class, usage);
532
533 printk(" (");
534 __print_lock_name(class);
535 printk("){%s}", usage);
536}
537
538static void print_lockdep_cache(struct lockdep_map *lock)
539{
540 const char *name;
541 char str[KSYM_NAME_LEN];
542
543 name = lock->name;
544 if (!name)
545 name = __get_key_name(lock->key->subkeys, str);
546
547 printk("%s", name);
548}
549
550static void print_lock(struct held_lock *hlock)
551{
552 print_lock_name(hlock_class(hlock));
553 printk(", at: ");
554 print_ip_sym(hlock->acquire_ip);
555}
556
557static void lockdep_print_held_locks(struct task_struct *curr)
558{
559 int i, depth = curr->lockdep_depth;
560
561 if (!depth) {
562 printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
563 return;
564 }
565 printk("%d lock%s held by %s/%d:\n",
566 depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
567
568 for (i = 0; i < depth; i++) {
569 printk(" #%d: ", i);
570 print_lock(curr->held_locks + i);
571 }
572}
573
574static void print_kernel_ident(void)
575{
576 printk("%s %.*s %s\n", init_utsname()->release,
577 (int)strcspn(init_utsname()->version, " "),
578 init_utsname()->version,
579 print_tainted());
580}
581
582static int very_verbose(struct lock_class *class)
583{
584#if VERY_VERBOSE
585 return class_filter(class);
586#endif
587 return 0;
588}
589
590
591
592
593static int static_obj(void *obj)
594{
595 unsigned long start = (unsigned long) &_stext,
596 end = (unsigned long) &_end,
597 addr = (unsigned long) obj;
598
599
600
601
602 if ((addr >= start) && (addr < end))
603 return 1;
604
605 if (arch_is_kernel_data(addr))
606 return 1;
607
608
609
610
611 if (is_kernel_percpu_address(addr))
612 return 1;
613
614
615
616
617 return is_module_address(addr) || is_module_percpu_address(addr);
618}
619
620
621
622
623
624static int count_matching_names(struct lock_class *new_class)
625{
626 struct lock_class *class;
627 int count = 0;
628
629 if (!new_class->name)
630 return 0;
631
632 list_for_each_entry(class, &all_lock_classes, lock_entry) {
633 if (new_class->key - new_class->subclass == class->key)
634 return class->name_version;
635 if (class->name && !strcmp(class->name, new_class->name))
636 count = max(count, class->name_version);
637 }
638
639 return count + 1;
640}
641
642
643
644
645
646
647static inline struct lock_class *
648look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
649{
650 struct lockdep_subclass_key *key;
651 struct list_head *hash_head;
652 struct lock_class *class;
653
654#ifdef CONFIG_DEBUG_LOCKDEP
655
656
657
658
659
660 if (unlikely(!lockdep_initialized)) {
661 lockdep_init();
662 lockdep_init_error = 1;
663 lock_init_error = lock->name;
664 save_stack_trace(&lockdep_init_trace);
665 }
666#endif
667
668 if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
669 debug_locks_off();
670 printk(KERN_ERR
671 "BUG: looking up invalid subclass: %u\n", subclass);
672 printk(KERN_ERR
673 "turning off the locking correctness validator.\n");
674 dump_stack();
675 return NULL;
676 }
677
678
679
680
681
682 if (unlikely(!lock->key))
683 lock->key = (void *)lock;
684
685
686
687
688
689
690
691 BUILD_BUG_ON(sizeof(struct lock_class_key) >
692 sizeof(struct lockdep_map));
693
694 key = lock->key->subkeys + subclass;
695
696 hash_head = classhashentry(key);
697
698
699
700
701
702 list_for_each_entry(class, hash_head, hash_entry) {
703 if (class->key == key) {
704
705
706
707
708 WARN_ON_ONCE(class->name != lock->name);
709 return class;
710 }
711 }
712
713 return NULL;
714}
715
716
717
718
719
720
721static inline struct lock_class *
722register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
723{
724 struct lockdep_subclass_key *key;
725 struct list_head *hash_head;
726 struct lock_class *class;
727 unsigned long flags;
728
729 class = look_up_lock_class(lock, subclass);
730 if (likely(class))
731 goto out_set_class_cache;
732
733
734
735
736 if (!static_obj(lock->key)) {
737 debug_locks_off();
738 printk("INFO: trying to register non-static key.\n");
739 printk("the code is fine but needs lockdep annotation.\n");
740 printk("turning off the locking correctness validator.\n");
741 dump_stack();
742
743 return NULL;
744 }
745
746 key = lock->key->subkeys + subclass;
747 hash_head = classhashentry(key);
748
749 raw_local_irq_save(flags);
750 if (!graph_lock()) {
751 raw_local_irq_restore(flags);
752 return NULL;
753 }
754
755
756
757
758 list_for_each_entry(class, hash_head, hash_entry)
759 if (class->key == key)
760 goto out_unlock_set;
761
762
763
764
765 if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
766 if (!debug_locks_off_graph_unlock()) {
767 raw_local_irq_restore(flags);
768 return NULL;
769 }
770 raw_local_irq_restore(flags);
771
772 print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
773 dump_stack();
774 return NULL;
775 }
776 class = lock_classes + nr_lock_classes++;
777 debug_atomic_inc(nr_unused_locks);
778 class->key = key;
779 class->name = lock->name;
780 class->subclass = subclass;
781 INIT_LIST_HEAD(&class->lock_entry);
782 INIT_LIST_HEAD(&class->locks_before);
783 INIT_LIST_HEAD(&class->locks_after);
784 class->name_version = count_matching_names(class);
785
786
787
788
789 list_add_tail_rcu(&class->hash_entry, hash_head);
790
791
792
793 list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
794
795 if (verbose(class)) {
796 graph_unlock();
797 raw_local_irq_restore(flags);
798
799 printk("\nnew class %p: %s", class->key, class->name);
800 if (class->name_version > 1)
801 printk("#%d", class->name_version);
802 printk("\n");
803 dump_stack();
804
805 raw_local_irq_save(flags);
806 if (!graph_lock()) {
807 raw_local_irq_restore(flags);
808 return NULL;
809 }
810 }
811out_unlock_set:
812 graph_unlock();
813 raw_local_irq_restore(flags);
814
815out_set_class_cache:
816 if (!subclass || force)
817 lock->class_cache[0] = class;
818 else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
819 lock->class_cache[subclass] = class;
820
821
822
823
824
825 if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
826 return NULL;
827
828 return class;
829}
830
831#ifdef CONFIG_PROVE_LOCKING
832
833
834
835
836static struct lock_list *alloc_list_entry(void)
837{
838 if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
839 if (!debug_locks_off_graph_unlock())
840 return NULL;
841
842 print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
843 dump_stack();
844 return NULL;
845 }
846 return list_entries + nr_list_entries++;
847}
848
849
850
851
852static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
853 struct list_head *head, unsigned long ip,
854 int distance, struct stack_trace *trace)
855{
856 struct lock_list *entry;
857
858
859
860
861 entry = alloc_list_entry();
862 if (!entry)
863 return 0;
864
865 entry->class = this;
866 entry->distance = distance;
867 entry->trace = *trace;
868
869
870
871
872
873
874
875 list_add_tail_rcu(&entry->entry, head);
876
877 return 1;
878}
879
880
881
882
883#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
884#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
885
886
887
888
889
890
891
892struct circular_queue {
893 unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
894 unsigned int front, rear;
895};
896
897static struct circular_queue lock_cq;
898
899unsigned int max_bfs_queue_depth;
900
901static unsigned int lockdep_dependency_gen_id;
902
903static inline void __cq_init(struct circular_queue *cq)
904{
905 cq->front = cq->rear = 0;
906 lockdep_dependency_gen_id++;
907}
908
909static inline int __cq_empty(struct circular_queue *cq)
910{
911 return (cq->front == cq->rear);
912}
913
914static inline int __cq_full(struct circular_queue *cq)
915{
916 return ((cq->rear + 1) & CQ_MASK) == cq->front;
917}
918
919static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
920{
921 if (__cq_full(cq))
922 return -1;
923
924 cq->element[cq->rear] = elem;
925 cq->rear = (cq->rear + 1) & CQ_MASK;
926 return 0;
927}
928
929static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
930{
931 if (__cq_empty(cq))
932 return -1;
933
934 *elem = cq->element[cq->front];
935 cq->front = (cq->front + 1) & CQ_MASK;
936 return 0;
937}
938
939static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
940{
941 return (cq->rear - cq->front) & CQ_MASK;
942}
943
944static inline void mark_lock_accessed(struct lock_list *lock,
945 struct lock_list *parent)
946{
947 unsigned long nr;
948
949 nr = lock - list_entries;
950 WARN_ON(nr >= nr_list_entries);
951 lock->parent = parent;
952 lock->class->dep_gen_id = lockdep_dependency_gen_id;
953}
954
955static inline unsigned long lock_accessed(struct lock_list *lock)
956{
957 unsigned long nr;
958
959 nr = lock - list_entries;
960 WARN_ON(nr >= nr_list_entries);
961 return lock->class->dep_gen_id == lockdep_dependency_gen_id;
962}
963
964static inline struct lock_list *get_lock_parent(struct lock_list *child)
965{
966 return child->parent;
967}
968
969static inline int get_lock_depth(struct lock_list *child)
970{
971 int depth = 0;
972 struct lock_list *parent;
973
974 while ((parent = get_lock_parent(child))) {
975 child = parent;
976 depth++;
977 }
978 return depth;
979}
980
981static int __bfs(struct lock_list *source_entry,
982 void *data,
983 int (*match)(struct lock_list *entry, void *data),
984 struct lock_list **target_entry,
985 int forward)
986{
987 struct lock_list *entry;
988 struct list_head *head;
989 struct circular_queue *cq = &lock_cq;
990 int ret = 1;
991
992 if (match(source_entry, data)) {
993 *target_entry = source_entry;
994 ret = 0;
995 goto exit;
996 }
997
998 if (forward)
999 head = &source_entry->class->locks_after;
1000 else
1001 head = &source_entry->class->locks_before;
1002
1003 if (list_empty(head))
1004 goto exit;
1005
1006 __cq_init(cq);
1007 __cq_enqueue(cq, (unsigned long)source_entry);
1008
1009 while (!__cq_empty(cq)) {
1010 struct lock_list *lock;
1011
1012 __cq_dequeue(cq, (unsigned long *)&lock);
1013
1014 if (!lock->class) {
1015 ret = -2;
1016 goto exit;
1017 }
1018
1019 if (forward)
1020 head = &lock->class->locks_after;
1021 else
1022 head = &lock->class->locks_before;
1023
1024 list_for_each_entry(entry, head, entry) {
1025 if (!lock_accessed(entry)) {
1026 unsigned int cq_depth;
1027 mark_lock_accessed(entry, lock);
1028 if (match(entry, data)) {
1029 *target_entry = entry;
1030 ret = 0;
1031 goto exit;
1032 }
1033
1034 if (__cq_enqueue(cq, (unsigned long)entry)) {
1035 ret = -1;
1036 goto exit;
1037 }
1038 cq_depth = __cq_get_elem_count(cq);
1039 if (max_bfs_queue_depth < cq_depth)
1040 max_bfs_queue_depth = cq_depth;
1041 }
1042 }
1043 }
1044exit:
1045 return ret;
1046}
1047
1048static inline int __bfs_forwards(struct lock_list *src_entry,
1049 void *data,
1050 int (*match)(struct lock_list *entry, void *data),
1051 struct lock_list **target_entry)
1052{
1053 return __bfs(src_entry, data, match, target_entry, 1);
1054
1055}
1056
1057static inline int __bfs_backwards(struct lock_list *src_entry,
1058 void *data,
1059 int (*match)(struct lock_list *entry, void *data),
1060 struct lock_list **target_entry)
1061{
1062 return __bfs(src_entry, data, match, target_entry, 0);
1063
1064}
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076static noinline int
1077print_circular_bug_entry(struct lock_list *target, int depth)
1078{
1079 if (debug_locks_silent)
1080 return 0;
1081 printk("\n-> #%u", depth);
1082 print_lock_name(target->class);
1083 printk(":\n");
1084 print_stack_trace(&target->trace, 6);
1085
1086 return 0;
1087}
1088
1089static void
1090print_circular_lock_scenario(struct held_lock *src,
1091 struct held_lock *tgt,
1092 struct lock_list *prt)
1093{
1094 struct lock_class *source = hlock_class(src);
1095 struct lock_class *target = hlock_class(tgt);
1096 struct lock_class *parent = prt->class;
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111 if (parent != source) {
1112 printk("Chain exists of:\n ");
1113 __print_lock_name(source);
1114 printk(" --> ");
1115 __print_lock_name(parent);
1116 printk(" --> ");
1117 __print_lock_name(target);
1118 printk("\n\n");
1119 }
1120
1121 printk(" Possible unsafe locking scenario:\n\n");
1122 printk(" CPU0 CPU1\n");
1123 printk(" ---- ----\n");
1124 printk(" lock(");
1125 __print_lock_name(target);
1126 printk(");\n");
1127 printk(" lock(");
1128 __print_lock_name(parent);
1129 printk(");\n");
1130 printk(" lock(");
1131 __print_lock_name(target);
1132 printk(");\n");
1133 printk(" lock(");
1134 __print_lock_name(source);
1135 printk(");\n");
1136 printk("\n *** DEADLOCK ***\n\n");
1137}
1138
1139
1140
1141
1142
1143static noinline int
1144print_circular_bug_header(struct lock_list *entry, unsigned int depth,
1145 struct held_lock *check_src,
1146 struct held_lock *check_tgt)
1147{
1148 struct task_struct *curr = current;
1149
1150 if (debug_locks_silent)
1151 return 0;
1152
1153 printk("\n");
1154 printk("======================================================\n");
1155 printk("[ INFO: possible circular locking dependency detected ]\n");
1156 print_kernel_ident();
1157 printk("-------------------------------------------------------\n");
1158 printk("%s/%d is trying to acquire lock:\n",
1159 curr->comm, task_pid_nr(curr));
1160 print_lock(check_src);
1161 printk("\nbut task is already holding lock:\n");
1162 print_lock(check_tgt);
1163 printk("\nwhich lock already depends on the new lock.\n\n");
1164 printk("\nthe existing dependency chain (in reverse order) is:\n");
1165
1166 print_circular_bug_entry(entry, depth);
1167
1168 return 0;
1169}
1170
1171static inline int class_equal(struct lock_list *entry, void *data)
1172{
1173 return entry->class == data;
1174}
1175
1176static noinline int print_circular_bug(struct lock_list *this,
1177 struct lock_list *target,
1178 struct held_lock *check_src,
1179 struct held_lock *check_tgt)
1180{
1181 struct task_struct *curr = current;
1182 struct lock_list *parent;
1183 struct lock_list *first_parent;
1184 int depth;
1185
1186 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1187 return 0;
1188
1189 if (!save_trace(&this->trace))
1190 return 0;
1191
1192 depth = get_lock_depth(target);
1193
1194 print_circular_bug_header(target, depth, check_src, check_tgt);
1195
1196 parent = get_lock_parent(target);
1197 first_parent = parent;
1198
1199 while (parent) {
1200 print_circular_bug_entry(parent, --depth);
1201 parent = get_lock_parent(parent);
1202 }
1203
1204 printk("\nother info that might help us debug this:\n\n");
1205 print_circular_lock_scenario(check_src, check_tgt,
1206 first_parent);
1207
1208 lockdep_print_held_locks(curr);
1209
1210 printk("\nstack backtrace:\n");
1211 dump_stack();
1212
1213 return 0;
1214}
1215
1216static noinline int print_bfs_bug(int ret)
1217{
1218 if (!debug_locks_off_graph_unlock())
1219 return 0;
1220
1221
1222
1223
1224 WARN(1, "lockdep bfs error:%d\n", ret);
1225
1226 return 0;
1227}
1228
1229static int noop_count(struct lock_list *entry, void *data)
1230{
1231 (*(unsigned long *)data)++;
1232 return 0;
1233}
1234
1235unsigned long __lockdep_count_forward_deps(struct lock_list *this)
1236{
1237 unsigned long count = 0;
1238 struct lock_list *uninitialized_var(target_entry);
1239
1240 __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
1241
1242 return count;
1243}
1244unsigned long lockdep_count_forward_deps(struct lock_class *class)
1245{
1246 unsigned long ret, flags;
1247 struct lock_list this;
1248
1249 this.parent = NULL;
1250 this.class = class;
1251
1252 local_irq_save(flags);
1253 arch_spin_lock(&lockdep_lock);
1254 ret = __lockdep_count_forward_deps(&this);
1255 arch_spin_unlock(&lockdep_lock);
1256 local_irq_restore(flags);
1257
1258 return ret;
1259}
1260
1261unsigned long __lockdep_count_backward_deps(struct lock_list *this)
1262{
1263 unsigned long count = 0;
1264 struct lock_list *uninitialized_var(target_entry);
1265
1266 __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
1267
1268 return count;
1269}
1270
1271unsigned long lockdep_count_backward_deps(struct lock_class *class)
1272{
1273 unsigned long ret, flags;
1274 struct lock_list this;
1275
1276 this.parent = NULL;
1277 this.class = class;
1278
1279 local_irq_save(flags);
1280 arch_spin_lock(&lockdep_lock);
1281 ret = __lockdep_count_backward_deps(&this);
1282 arch_spin_unlock(&lockdep_lock);
1283 local_irq_restore(flags);
1284
1285 return ret;
1286}
1287
1288
1289
1290
1291
1292static noinline int
1293check_noncircular(struct lock_list *root, struct lock_class *target,
1294 struct lock_list **target_entry)
1295{
1296 int result;
1297
1298 debug_atomic_inc(nr_cyclic_checks);
1299
1300 result = __bfs_forwards(root, target, class_equal, target_entry);
1301
1302 return result;
1303}
1304
1305#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
1306
1307
1308
1309
1310
1311
1312static inline int usage_match(struct lock_list *entry, void *bit)
1313{
1314 return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
1315}
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329static int
1330find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
1331 struct lock_list **target_entry)
1332{
1333 int result;
1334
1335 debug_atomic_inc(nr_find_usage_forwards_checks);
1336
1337 result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
1338
1339 return result;
1340}
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352static int
1353find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
1354 struct lock_list **target_entry)
1355{
1356 int result;
1357
1358 debug_atomic_inc(nr_find_usage_backwards_checks);
1359
1360 result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
1361
1362 return result;
1363}
1364
1365static void print_lock_class_header(struct lock_class *class, int depth)
1366{
1367 int bit;
1368
1369 printk("%*s->", depth, "");
1370 print_lock_name(class);
1371 printk(" ops: %lu", class->ops);
1372 printk(" {\n");
1373
1374 for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
1375 if (class->usage_mask & (1 << bit)) {
1376 int len = depth;
1377
1378 len += printk("%*s %s", depth, "", usage_str[bit]);
1379 len += printk(" at:\n");
1380 print_stack_trace(class->usage_traces + bit, len);
1381 }
1382 }
1383 printk("%*s }\n", depth, "");
1384
1385 printk("%*s ... key at: ",depth,"");
1386 print_ip_sym((unsigned long)class->key);
1387}
1388
1389
1390
1391
1392static void __used
1393print_shortest_lock_dependencies(struct lock_list *leaf,
1394 struct lock_list *root)
1395{
1396 struct lock_list *entry = leaf;
1397 int depth;
1398
1399
1400 depth = get_lock_depth(leaf);
1401
1402 do {
1403 print_lock_class_header(entry->class, depth);
1404 printk("%*s ... acquired at:\n", depth, "");
1405 print_stack_trace(&entry->trace, 2);
1406 printk("\n");
1407
1408 if (depth == 0 && (entry != root)) {
1409 printk("lockdep:%s bad path found in chain graph\n", __func__);
1410 break;
1411 }
1412
1413 entry = get_lock_parent(entry);
1414 depth--;
1415 } while (entry && (depth >= 0));
1416
1417 return;
1418}
1419
1420static void
1421print_irq_lock_scenario(struct lock_list *safe_entry,
1422 struct lock_list *unsafe_entry,
1423 struct lock_class *prev_class,
1424 struct lock_class *next_class)
1425{
1426 struct lock_class *safe_class = safe_entry->class;
1427 struct lock_class *unsafe_class = unsafe_entry->class;
1428 struct lock_class *middle_class = prev_class;
1429
1430 if (middle_class == safe_class)
1431 middle_class = next_class;
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446 if (middle_class != unsafe_class) {
1447 printk("Chain exists of:\n ");
1448 __print_lock_name(safe_class);
1449 printk(" --> ");
1450 __print_lock_name(middle_class);
1451 printk(" --> ");
1452 __print_lock_name(unsafe_class);
1453 printk("\n\n");
1454 }
1455
1456 printk(" Possible interrupt unsafe locking scenario:\n\n");
1457 printk(" CPU0 CPU1\n");
1458 printk(" ---- ----\n");
1459 printk(" lock(");
1460 __print_lock_name(unsafe_class);
1461 printk(");\n");
1462 printk(" local_irq_disable();\n");
1463 printk(" lock(");
1464 __print_lock_name(safe_class);
1465 printk(");\n");
1466 printk(" lock(");
1467 __print_lock_name(middle_class);
1468 printk(");\n");
1469 printk(" <Interrupt>\n");
1470 printk(" lock(");
1471 __print_lock_name(safe_class);
1472 printk(");\n");
1473 printk("\n *** DEADLOCK ***\n\n");
1474}
1475
1476static int
1477print_bad_irq_dependency(struct task_struct *curr,
1478 struct lock_list *prev_root,
1479 struct lock_list *next_root,
1480 struct lock_list *backwards_entry,
1481 struct lock_list *forwards_entry,
1482 struct held_lock *prev,
1483 struct held_lock *next,
1484 enum lock_usage_bit bit1,
1485 enum lock_usage_bit bit2,
1486 const char *irqclass)
1487{
1488 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1489 return 0;
1490
1491 printk("\n");
1492 printk("======================================================\n");
1493 printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
1494 irqclass, irqclass);
1495 print_kernel_ident();
1496 printk("------------------------------------------------------\n");
1497 printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
1498 curr->comm, task_pid_nr(curr),
1499 curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
1500 curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
1501 curr->hardirqs_enabled,
1502 curr->softirqs_enabled);
1503 print_lock(next);
1504
1505 printk("\nand this task is already holding:\n");
1506 print_lock(prev);
1507 printk("which would create a new lock dependency:\n");
1508 print_lock_name(hlock_class(prev));
1509 printk(" ->");
1510 print_lock_name(hlock_class(next));
1511 printk("\n");
1512
1513 printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
1514 irqclass);
1515 print_lock_name(backwards_entry->class);
1516 printk("\n... which became %s-irq-safe at:\n", irqclass);
1517
1518 print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
1519
1520 printk("\nto a %s-irq-unsafe lock:\n", irqclass);
1521 print_lock_name(forwards_entry->class);
1522 printk("\n... which became %s-irq-unsafe at:\n", irqclass);
1523 printk("...");
1524
1525 print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
1526
1527 printk("\nother info that might help us debug this:\n\n");
1528 print_irq_lock_scenario(backwards_entry, forwards_entry,
1529 hlock_class(prev), hlock_class(next));
1530
1531 lockdep_print_held_locks(curr);
1532
1533 printk("\nthe dependencies between %s-irq-safe lock", irqclass);
1534 printk(" and the holding lock:\n");
1535 if (!save_trace(&prev_root->trace))
1536 return 0;
1537 print_shortest_lock_dependencies(backwards_entry, prev_root);
1538
1539 printk("\nthe dependencies between the lock to be acquired");
1540 printk(" and %s-irq-unsafe lock:\n", irqclass);
1541 if (!save_trace(&next_root->trace))
1542 return 0;
1543 print_shortest_lock_dependencies(forwards_entry, next_root);
1544
1545 printk("\nstack backtrace:\n");
1546 dump_stack();
1547
1548 return 0;
1549}
1550
1551static int
1552check_usage(struct task_struct *curr, struct held_lock *prev,
1553 struct held_lock *next, enum lock_usage_bit bit_backwards,
1554 enum lock_usage_bit bit_forwards, const char *irqclass)
1555{
1556 int ret;
1557 struct lock_list this, that;
1558 struct lock_list *uninitialized_var(target_entry);
1559 struct lock_list *uninitialized_var(target_entry1);
1560
1561 this.parent = NULL;
1562
1563 this.class = hlock_class(prev);
1564 ret = find_usage_backwards(&this, bit_backwards, &target_entry);
1565 if (ret < 0)
1566 return print_bfs_bug(ret);
1567 if (ret == 1)
1568 return ret;
1569
1570 that.parent = NULL;
1571 that.class = hlock_class(next);
1572 ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
1573 if (ret < 0)
1574 return print_bfs_bug(ret);
1575 if (ret == 1)
1576 return ret;
1577
1578 return print_bad_irq_dependency(curr, &this, &that,
1579 target_entry, target_entry1,
1580 prev, next,
1581 bit_backwards, bit_forwards, irqclass);
1582}
1583
1584static const char *state_names[] = {
1585#define LOCKDEP_STATE(__STATE) \
1586 __stringify(__STATE),
1587#include "lockdep_states.h"
1588#undef LOCKDEP_STATE
1589};
1590
1591static const char *state_rnames[] = {
1592#define LOCKDEP_STATE(__STATE) \
1593 __stringify(__STATE)"-READ",
1594#include "lockdep_states.h"
1595#undef LOCKDEP_STATE
1596};
1597
1598static inline const char *state_name(enum lock_usage_bit bit)
1599{
1600 return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
1601}
1602
1603static int exclusive_bit(int new_bit)
1604{
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616 int state = new_bit & ~3;
1617 int dir = new_bit & 2;
1618
1619
1620
1621
1622 return state | (dir ^ 2);
1623}
1624
1625static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
1626 struct held_lock *next, enum lock_usage_bit bit)
1627{
1628
1629
1630
1631
1632
1633
1634 if (!check_usage(curr, prev, next, bit,
1635 exclusive_bit(bit), state_name(bit)))
1636 return 0;
1637
1638 bit++;
1639
1640
1641
1642
1643
1644
1645
1646 if (!check_usage(curr, prev, next, bit,
1647 exclusive_bit(bit), state_name(bit)))
1648 return 0;
1649
1650 return 1;
1651}
1652
1653static int
1654check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1655 struct held_lock *next)
1656{
1657#define LOCKDEP_STATE(__STATE) \
1658 if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
1659 return 0;
1660#include "lockdep_states.h"
1661#undef LOCKDEP_STATE
1662
1663 return 1;
1664}
1665
1666static void inc_chains(void)
1667{
1668 if (current->hardirq_context)
1669 nr_hardirq_chains++;
1670 else {
1671 if (current->softirq_context)
1672 nr_softirq_chains++;
1673 else
1674 nr_process_chains++;
1675 }
1676}
1677
1678#else
1679
1680static inline int
1681check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1682 struct held_lock *next)
1683{
1684 return 1;
1685}
1686
1687static inline void inc_chains(void)
1688{
1689 nr_process_chains++;
1690}
1691
1692#endif
1693
1694static void
1695print_deadlock_scenario(struct held_lock *nxt,
1696 struct held_lock *prv)
1697{
1698 struct lock_class *next = hlock_class(nxt);
1699 struct lock_class *prev = hlock_class(prv);
1700
1701 printk(" Possible unsafe locking scenario:\n\n");
1702 printk(" CPU0\n");
1703 printk(" ----\n");
1704 printk(" lock(");
1705 __print_lock_name(prev);
1706 printk(");\n");
1707 printk(" lock(");
1708 __print_lock_name(next);
1709 printk(");\n");
1710 printk("\n *** DEADLOCK ***\n\n");
1711 printk(" May be due to missing lock nesting notation\n\n");
1712}
1713
1714static int
1715print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
1716 struct held_lock *next)
1717{
1718 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1719 return 0;
1720
1721 printk("\n");
1722 printk("=============================================\n");
1723 printk("[ INFO: possible recursive locking detected ]\n");
1724 print_kernel_ident();
1725 printk("---------------------------------------------\n");
1726 printk("%s/%d is trying to acquire lock:\n",
1727 curr->comm, task_pid_nr(curr));
1728 print_lock(next);
1729 printk("\nbut task is already holding lock:\n");
1730 print_lock(prev);
1731
1732 printk("\nother info that might help us debug this:\n");
1733 print_deadlock_scenario(next, prev);
1734 lockdep_print_held_locks(curr);
1735
1736 printk("\nstack backtrace:\n");
1737 dump_stack();
1738
1739 return 0;
1740}
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750static int
1751check_deadlock(struct task_struct *curr, struct held_lock *next,
1752 struct lockdep_map *next_instance, int read)
1753{
1754 struct held_lock *prev;
1755 struct held_lock *nest = NULL;
1756 int i;
1757
1758 for (i = 0; i < curr->lockdep_depth; i++) {
1759 prev = curr->held_locks + i;
1760
1761 if (prev->instance == next->nest_lock)
1762 nest = prev;
1763
1764 if (hlock_class(prev) != hlock_class(next))
1765 continue;
1766
1767
1768
1769
1770
1771 if ((read == 2) && prev->read)
1772 return 2;
1773
1774
1775
1776
1777
1778 if (nest)
1779 return 2;
1780
1781 return print_deadlock_bug(curr, prev, next);
1782 }
1783 return 1;
1784}
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808static int
1809check_prev_add(struct task_struct *curr, struct held_lock *prev,
1810 struct held_lock *next, int distance, int trylock_loop)
1811{
1812 struct lock_list *entry;
1813 int ret;
1814 struct lock_list this;
1815 struct lock_list *uninitialized_var(target_entry);
1816
1817
1818
1819
1820
1821
1822
1823 static struct stack_trace trace;
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834 this.class = hlock_class(next);
1835 this.parent = NULL;
1836 ret = check_noncircular(&this, hlock_class(prev), &target_entry);
1837 if (unlikely(!ret))
1838 return print_circular_bug(&this, target_entry, next, prev);
1839 else if (unlikely(ret < 0))
1840 return print_bfs_bug(ret);
1841
1842 if (!check_prev_add_irq(curr, prev, next))
1843 return 0;
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853 if (next->read == 2 || prev->read == 2)
1854 return 1;
1855
1856
1857
1858
1859
1860
1861
1862
1863 list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
1864 if (entry->class == hlock_class(next)) {
1865 if (distance == 1)
1866 entry->distance = 1;
1867 return 2;
1868 }
1869 }
1870
1871 if (!trylock_loop && !save_trace(&trace))
1872 return 0;
1873
1874
1875
1876
1877
1878 ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
1879 &hlock_class(prev)->locks_after,
1880 next->acquire_ip, distance, &trace);
1881
1882 if (!ret)
1883 return 0;
1884
1885 ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
1886 &hlock_class(next)->locks_before,
1887 next->acquire_ip, distance, &trace);
1888 if (!ret)
1889 return 0;
1890
1891
1892
1893
1894 if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
1895 graph_unlock();
1896 printk("\n new dependency: ");
1897 print_lock_name(hlock_class(prev));
1898 printk(" => ");
1899 print_lock_name(hlock_class(next));
1900 printk("\n");
1901 dump_stack();
1902 return graph_lock();
1903 }
1904 return 1;
1905}
1906
1907
1908
1909
1910
1911
1912
1913static int
1914check_prevs_add(struct task_struct *curr, struct held_lock *next)
1915{
1916 int depth = curr->lockdep_depth;
1917 int trylock_loop = 0;
1918 struct held_lock *hlock;
1919
1920
1921
1922
1923
1924
1925 if (!depth)
1926 goto out_bug;
1927
1928
1929
1930
1931 if (curr->held_locks[depth].irq_context !=
1932 curr->held_locks[depth-1].irq_context)
1933 goto out_bug;
1934
1935 for (;;) {
1936 int distance = curr->lockdep_depth - depth + 1;
1937 hlock = curr->held_locks + depth-1;
1938
1939
1940
1941
1942 if (hlock->read != 2) {
1943 if (!check_prev_add(curr, hlock, next,
1944 distance, trylock_loop))
1945 return 0;
1946
1947
1948
1949
1950
1951
1952 if (!hlock->trylock)
1953 break;
1954 }
1955 depth--;
1956
1957
1958
1959 if (!depth)
1960 break;
1961
1962
1963
1964 if (curr->held_locks[depth].irq_context !=
1965 curr->held_locks[depth-1].irq_context)
1966 break;
1967 trylock_loop = 1;
1968 }
1969 return 1;
1970out_bug:
1971 if (!debug_locks_off_graph_unlock())
1972 return 0;
1973
1974
1975
1976
1977
1978
1979 WARN_ON(1);
1980
1981 return 0;
1982}
1983
1984unsigned long nr_lock_chains;
1985struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
1986int nr_chain_hlocks;
1987static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
1988
1989struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
1990{
1991 return lock_classes + chain_hlocks[chain->base + i];
1992}
1993
1994
1995
1996
1997
1998
1999
2000static inline int lookup_chain_cache(struct task_struct *curr,
2001 struct held_lock *hlock,
2002 u64 chain_key)
2003{
2004 struct lock_class *class = hlock_class(hlock);
2005 struct list_head *hash_head = chainhashentry(chain_key);
2006 struct lock_chain *chain;
2007 struct held_lock *hlock_curr;
2008 int i, j;
2009
2010
2011
2012
2013
2014
2015 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2016 return 0;
2017
2018
2019
2020
2021 list_for_each_entry(chain, hash_head, entry) {
2022 if (chain->chain_key == chain_key) {
2023cache_hit:
2024 debug_atomic_inc(chain_lookup_hits);
2025 if (very_verbose(class))
2026 printk("\nhash chain already cached, key: "
2027 "%016Lx tail class: [%p] %s\n",
2028 (unsigned long long)chain_key,
2029 class->key, class->name);
2030 return 0;
2031 }
2032 }
2033 if (very_verbose(class))
2034 printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
2035 (unsigned long long)chain_key, class->key, class->name);
2036
2037
2038
2039
2040 if (!graph_lock())
2041 return 0;
2042
2043
2044
2045 list_for_each_entry(chain, hash_head, entry) {
2046 if (chain->chain_key == chain_key) {
2047 graph_unlock();
2048 goto cache_hit;
2049 }
2050 }
2051 if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
2052 if (!debug_locks_off_graph_unlock())
2053 return 0;
2054
2055 print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
2056 dump_stack();
2057 return 0;
2058 }
2059 chain = lock_chains + nr_lock_chains++;
2060 chain->chain_key = chain_key;
2061 chain->irq_context = hlock->irq_context;
2062
2063 for (i = curr->lockdep_depth - 1; i >= 0; i--) {
2064 hlock_curr = curr->held_locks + i;
2065 if (hlock_curr->irq_context != hlock->irq_context)
2066 break;
2067 }
2068 i++;
2069 chain->depth = curr->lockdep_depth + 1 - i;
2070 if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
2071 chain->base = nr_chain_hlocks;
2072 nr_chain_hlocks += chain->depth;
2073 for (j = 0; j < chain->depth - 1; j++, i++) {
2074 int lock_id = curr->held_locks[i].class_idx - 1;
2075 chain_hlocks[chain->base + j] = lock_id;
2076 }
2077 chain_hlocks[chain->base + j] = class - lock_classes;
2078 }
2079 list_add_tail_rcu(&chain->entry, hash_head);
2080 debug_atomic_inc(chain_lookup_misses);
2081 inc_chains();
2082
2083 return 1;
2084}
2085
2086static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
2087 struct held_lock *hlock, int chain_head, u64 chain_key)
2088{
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099 if (!hlock->trylock && (hlock->check == 2) &&
2100 lookup_chain_cache(curr, hlock, chain_key)) {
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113 int ret = check_deadlock(curr, hlock, lock, hlock->read);
2114
2115 if (!ret)
2116 return 0;
2117
2118
2119
2120
2121
2122 if (ret == 2)
2123 hlock->read = 2;
2124
2125
2126
2127
2128 if (!chain_head && ret != 2)
2129 if (!check_prevs_add(curr, hlock))
2130 return 0;
2131 graph_unlock();
2132 } else
2133
2134 if (unlikely(!debug_locks))
2135 return 0;
2136
2137 return 1;
2138}
2139#else
2140static inline int validate_chain(struct task_struct *curr,
2141 struct lockdep_map *lock, struct held_lock *hlock,
2142 int chain_head, u64 chain_key)
2143{
2144 return 1;
2145}
2146#endif
2147
2148
2149
2150
2151
2152static void check_chain_key(struct task_struct *curr)
2153{
2154#ifdef CONFIG_DEBUG_LOCKDEP
2155 struct held_lock *hlock, *prev_hlock = NULL;
2156 unsigned int i, id;
2157 u64 chain_key = 0;
2158
2159 for (i = 0; i < curr->lockdep_depth; i++) {
2160 hlock = curr->held_locks + i;
2161 if (chain_key != hlock->prev_chain_key) {
2162 debug_locks_off();
2163
2164
2165
2166
2167 WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
2168 curr->lockdep_depth, i,
2169 (unsigned long long)chain_key,
2170 (unsigned long long)hlock->prev_chain_key);
2171 return;
2172 }
2173 id = hlock->class_idx - 1;
2174
2175
2176
2177 if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
2178 return;
2179
2180 if (prev_hlock && (prev_hlock->irq_context !=
2181 hlock->irq_context))
2182 chain_key = 0;
2183 chain_key = iterate_chain_key(chain_key, id);
2184 prev_hlock = hlock;
2185 }
2186 if (chain_key != curr->curr_chain_key) {
2187 debug_locks_off();
2188
2189
2190
2191
2192 WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
2193 curr->lockdep_depth, i,
2194 (unsigned long long)chain_key,
2195 (unsigned long long)curr->curr_chain_key);
2196 }
2197#endif
2198}
2199
2200static void
2201print_usage_bug_scenario(struct held_lock *lock)
2202{
2203 struct lock_class *class = hlock_class(lock);
2204
2205 printk(" Possible unsafe locking scenario:\n\n");
2206 printk(" CPU0\n");
2207 printk(" ----\n");
2208 printk(" lock(");
2209 __print_lock_name(class);
2210 printk(");\n");
2211 printk(" <Interrupt>\n");
2212 printk(" lock(");
2213 __print_lock_name(class);
2214 printk(");\n");
2215 printk("\n *** DEADLOCK ***\n\n");
2216}
2217
2218static int
2219print_usage_bug(struct task_struct *curr, struct held_lock *this,
2220 enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
2221{
2222 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2223 return 0;
2224
2225 printk("\n");
2226 printk("=================================\n");
2227 printk("[ INFO: inconsistent lock state ]\n");
2228 print_kernel_ident();
2229 printk("---------------------------------\n");
2230
2231 printk("inconsistent {%s} -> {%s} usage.\n",
2232 usage_str[prev_bit], usage_str[new_bit]);
2233
2234 printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
2235 curr->comm, task_pid_nr(curr),
2236 trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
2237 trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
2238 trace_hardirqs_enabled(curr),
2239 trace_softirqs_enabled(curr));
2240 print_lock(this);
2241
2242 printk("{%s} state was registered at:\n", usage_str[prev_bit]);
2243 print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
2244
2245 print_irqtrace_events(curr);
2246 printk("\nother info that might help us debug this:\n");
2247 print_usage_bug_scenario(this);
2248
2249 lockdep_print_held_locks(curr);
2250
2251 printk("\nstack backtrace:\n");
2252 dump_stack();
2253
2254 return 0;
2255}
2256
2257
2258
2259
2260static inline int
2261valid_state(struct task_struct *curr, struct held_lock *this,
2262 enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
2263{
2264 if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
2265 return print_usage_bug(curr, this, bad_bit, new_bit);
2266 return 1;
2267}
2268
2269static int mark_lock(struct task_struct *curr, struct held_lock *this,
2270 enum lock_usage_bit new_bit);
2271
2272#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
2273
2274
2275
2276
2277static int
2278print_irq_inversion_bug(struct task_struct *curr,
2279 struct lock_list *root, struct lock_list *other,
2280 struct held_lock *this, int forwards,
2281 const char *irqclass)
2282{
2283 struct lock_list *entry = other;
2284 struct lock_list *middle = NULL;
2285 int depth;
2286
2287 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2288 return 0;
2289
2290 printk("\n");
2291 printk("=========================================================\n");
2292 printk("[ INFO: possible irq lock inversion dependency detected ]\n");
2293 print_kernel_ident();
2294 printk("---------------------------------------------------------\n");
2295 printk("%s/%d just changed the state of lock:\n",
2296 curr->comm, task_pid_nr(curr));
2297 print_lock(this);
2298 if (forwards)
2299 printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
2300 else
2301 printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
2302 print_lock_name(other->class);
2303 printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
2304
2305 printk("\nother info that might help us debug this:\n");
2306
2307
2308 depth = get_lock_depth(other);
2309 do {
2310 if (depth == 0 && (entry != root)) {
2311 printk("lockdep:%s bad path found in chain graph\n", __func__);
2312 break;
2313 }
2314 middle = entry;
2315 entry = get_lock_parent(entry);
2316 depth--;
2317 } while (entry && entry != root && (depth >= 0));
2318 if (forwards)
2319 print_irq_lock_scenario(root, other,
2320 middle ? middle->class : root->class, other->class);
2321 else
2322 print_irq_lock_scenario(other, root,
2323 middle ? middle->class : other->class, root->class);
2324
2325 lockdep_print_held_locks(curr);
2326
2327 printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
2328 if (!save_trace(&root->trace))
2329 return 0;
2330 print_shortest_lock_dependencies(other, root);
2331
2332 printk("\nstack backtrace:\n");
2333 dump_stack();
2334
2335 return 0;
2336}
2337
2338
2339
2340
2341
2342static int
2343check_usage_forwards(struct task_struct *curr, struct held_lock *this,
2344 enum lock_usage_bit bit, const char *irqclass)
2345{
2346 int ret;
2347 struct lock_list root;
2348 struct lock_list *uninitialized_var(target_entry);
2349
2350 root.parent = NULL;
2351 root.class = hlock_class(this);
2352 ret = find_usage_forwards(&root, bit, &target_entry);
2353 if (ret < 0)
2354 return print_bfs_bug(ret);
2355 if (ret == 1)
2356 return ret;
2357
2358 return print_irq_inversion_bug(curr, &root, target_entry,
2359 this, 1, irqclass);
2360}
2361
2362
2363
2364
2365
2366static int
2367check_usage_backwards(struct task_struct *curr, struct held_lock *this,
2368 enum lock_usage_bit bit, const char *irqclass)
2369{
2370 int ret;
2371 struct lock_list root;
2372 struct lock_list *uninitialized_var(target_entry);
2373
2374 root.parent = NULL;
2375 root.class = hlock_class(this);
2376 ret = find_usage_backwards(&root, bit, &target_entry);
2377 if (ret < 0)
2378 return print_bfs_bug(ret);
2379 if (ret == 1)
2380 return ret;
2381
2382 return print_irq_inversion_bug(curr, &root, target_entry,
2383 this, 0, irqclass);
2384}
2385
2386void print_irqtrace_events(struct task_struct *curr)
2387{
2388 printk("irq event stamp: %u\n", curr->irq_events);
2389 printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
2390 print_ip_sym(curr->hardirq_enable_ip);
2391 printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
2392 print_ip_sym(curr->hardirq_disable_ip);
2393 printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
2394 print_ip_sym(curr->softirq_enable_ip);
2395 printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
2396 print_ip_sym(curr->softirq_disable_ip);
2397}
2398
2399static int HARDIRQ_verbose(struct lock_class *class)
2400{
2401#if HARDIRQ_VERBOSE
2402 return class_filter(class);
2403#endif
2404 return 0;
2405}
2406
2407static int SOFTIRQ_verbose(struct lock_class *class)
2408{
2409#if SOFTIRQ_VERBOSE
2410 return class_filter(class);
2411#endif
2412 return 0;
2413}
2414
2415static int RECLAIM_FS_verbose(struct lock_class *class)
2416{
2417#if RECLAIM_VERBOSE
2418 return class_filter(class);
2419#endif
2420 return 0;
2421}
2422
2423#define STRICT_READ_CHECKS 1
2424
2425static int (*state_verbose_f[])(struct lock_class *class) = {
2426#define LOCKDEP_STATE(__STATE) \
2427 __STATE##_verbose,
2428#include "lockdep_states.h"
2429#undef LOCKDEP_STATE
2430};
2431
2432static inline int state_verbose(enum lock_usage_bit bit,
2433 struct lock_class *class)
2434{
2435 return state_verbose_f[bit >> 2](class);
2436}
2437
2438typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
2439 enum lock_usage_bit bit, const char *name);
2440
2441static int
2442mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2443 enum lock_usage_bit new_bit)
2444{
2445 int excl_bit = exclusive_bit(new_bit);
2446 int read = new_bit & 1;
2447 int dir = new_bit & 2;
2448
2449
2450
2451
2452
2453
2454
2455
2456 check_usage_f usage = dir ?
2457 check_usage_backwards : check_usage_forwards;
2458
2459
2460
2461
2462
2463 if (!valid_state(curr, this, new_bit, excl_bit))
2464 return 0;
2465
2466
2467
2468
2469
2470 if ((!read || !dir || STRICT_READ_CHECKS) &&
2471 !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
2472 return 0;
2473
2474
2475
2476
2477 if (!read) {
2478 if (!valid_state(curr, this, new_bit, excl_bit + 1))
2479 return 0;
2480
2481 if (STRICT_READ_CHECKS &&
2482 !usage(curr, this, excl_bit + 1,
2483 state_name(new_bit + 1)))
2484 return 0;
2485 }
2486
2487 if (state_verbose(new_bit, hlock_class(this)))
2488 return 2;
2489
2490 return 1;
2491}
2492
2493enum mark_type {
2494#define LOCKDEP_STATE(__STATE) __STATE,
2495#include "lockdep_states.h"
2496#undef LOCKDEP_STATE
2497};
2498
2499
2500
2501
2502static int
2503mark_held_locks(struct task_struct *curr, enum mark_type mark)
2504{
2505 enum lock_usage_bit usage_bit;
2506 struct held_lock *hlock;
2507 int i;
2508
2509 for (i = 0; i < curr->lockdep_depth; i++) {
2510 hlock = curr->held_locks + i;
2511
2512 usage_bit = 2 + (mark << 2);
2513 if (hlock->read)
2514 usage_bit += 1;
2515
2516 BUG_ON(usage_bit >= LOCK_USAGE_STATES);
2517
2518 if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys)
2519 continue;
2520
2521 if (!mark_lock(curr, hlock, usage_bit))
2522 return 0;
2523 }
2524
2525 return 1;
2526}
2527
2528
2529
2530
2531static void __trace_hardirqs_on_caller(unsigned long ip)
2532{
2533 struct task_struct *curr = current;
2534
2535
2536 curr->hardirqs_enabled = 1;
2537
2538
2539
2540
2541
2542 if (!mark_held_locks(curr, HARDIRQ))
2543 return;
2544
2545
2546
2547
2548
2549 if (curr->softirqs_enabled)
2550 if (!mark_held_locks(curr, SOFTIRQ))
2551 return;
2552
2553 curr->hardirq_enable_ip = ip;
2554 curr->hardirq_enable_event = ++curr->irq_events;
2555 debug_atomic_inc(hardirqs_on_events);
2556}
2557
2558void trace_hardirqs_on_caller(unsigned long ip)
2559{
2560 time_hardirqs_on(CALLER_ADDR0, ip);
2561
2562 if (unlikely(!debug_locks || current->lockdep_recursion))
2563 return;
2564
2565 if (unlikely(current->hardirqs_enabled)) {
2566
2567
2568
2569
2570
2571 __debug_atomic_inc(redundant_hardirqs_on);
2572 return;
2573 }
2574
2575
2576
2577
2578
2579
2580 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2581 return;
2582
2583
2584
2585
2586 if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
2587 return;
2588
2589
2590
2591
2592
2593 if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
2594 return;
2595
2596 current->lockdep_recursion = 1;
2597 __trace_hardirqs_on_caller(ip);
2598 current->lockdep_recursion = 0;
2599}
2600EXPORT_SYMBOL(trace_hardirqs_on_caller);
2601
2602void trace_hardirqs_on(void)
2603{
2604 trace_hardirqs_on_caller(CALLER_ADDR0);
2605}
2606EXPORT_SYMBOL(trace_hardirqs_on);
2607
2608
2609
2610
2611void trace_hardirqs_off_caller(unsigned long ip)
2612{
2613 struct task_struct *curr = current;
2614
2615 time_hardirqs_off(CALLER_ADDR0, ip);
2616
2617 if (unlikely(!debug_locks || current->lockdep_recursion))
2618 return;
2619
2620
2621
2622
2623
2624 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2625 return;
2626
2627 if (curr->hardirqs_enabled) {
2628
2629
2630
2631 curr->hardirqs_enabled = 0;
2632 curr->hardirq_disable_ip = ip;
2633 curr->hardirq_disable_event = ++curr->irq_events;
2634 debug_atomic_inc(hardirqs_off_events);
2635 } else
2636 debug_atomic_inc(redundant_hardirqs_off);
2637}
2638EXPORT_SYMBOL(trace_hardirqs_off_caller);
2639
2640void trace_hardirqs_off(void)
2641{
2642 trace_hardirqs_off_caller(CALLER_ADDR0);
2643}
2644EXPORT_SYMBOL(trace_hardirqs_off);
2645
2646
2647
2648
2649void trace_softirqs_on(unsigned long ip)
2650{
2651 struct task_struct *curr = current;
2652
2653 if (unlikely(!debug_locks || current->lockdep_recursion))
2654 return;
2655
2656
2657
2658
2659
2660 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2661 return;
2662
2663 if (curr->softirqs_enabled) {
2664 debug_atomic_inc(redundant_softirqs_on);
2665 return;
2666 }
2667
2668 current->lockdep_recursion = 1;
2669
2670
2671
2672 curr->softirqs_enabled = 1;
2673 curr->softirq_enable_ip = ip;
2674 curr->softirq_enable_event = ++curr->irq_events;
2675 debug_atomic_inc(softirqs_on_events);
2676
2677
2678
2679
2680
2681 if (curr->hardirqs_enabled)
2682 mark_held_locks(curr, SOFTIRQ);
2683 current->lockdep_recursion = 0;
2684}
2685
2686
2687
2688
2689void trace_softirqs_off(unsigned long ip)
2690{
2691 struct task_struct *curr = current;
2692
2693 if (unlikely(!debug_locks || current->lockdep_recursion))
2694 return;
2695
2696
2697
2698
2699 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2700 return;
2701
2702 if (curr->softirqs_enabled) {
2703
2704
2705
2706 curr->softirqs_enabled = 0;
2707 curr->softirq_disable_ip = ip;
2708 curr->softirq_disable_event = ++curr->irq_events;
2709 debug_atomic_inc(softirqs_off_events);
2710
2711
2712
2713 DEBUG_LOCKS_WARN_ON(!softirq_count());
2714 } else
2715 debug_atomic_inc(redundant_softirqs_off);
2716}
2717
2718static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
2719{
2720 struct task_struct *curr = current;
2721
2722 if (unlikely(!debug_locks))
2723 return;
2724
2725
2726 if (!(gfp_mask & __GFP_WAIT))
2727 return;
2728
2729
2730 if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
2731 return;
2732
2733
2734 if (!(gfp_mask & __GFP_FS))
2735 return;
2736
2737
2738
2739
2740 if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
2741 return;
2742
2743 mark_held_locks(curr, RECLAIM_FS);
2744}
2745
2746static void check_flags(unsigned long flags);
2747
2748void lockdep_trace_alloc(gfp_t gfp_mask)
2749{
2750 unsigned long flags;
2751
2752 if (unlikely(current->lockdep_recursion))
2753 return;
2754
2755 raw_local_irq_save(flags);
2756 check_flags(flags);
2757 current->lockdep_recursion = 1;
2758 __lockdep_trace_alloc(gfp_mask, flags);
2759 current->lockdep_recursion = 0;
2760 raw_local_irq_restore(flags);
2761}
2762
2763static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
2764{
2765
2766
2767
2768
2769 if (!hlock->trylock) {
2770 if (hlock->read) {
2771 if (curr->hardirq_context)
2772 if (!mark_lock(curr, hlock,
2773 LOCK_USED_IN_HARDIRQ_READ))
2774 return 0;
2775 if (curr->softirq_context)
2776 if (!mark_lock(curr, hlock,
2777 LOCK_USED_IN_SOFTIRQ_READ))
2778 return 0;
2779 } else {
2780 if (curr->hardirq_context)
2781 if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
2782 return 0;
2783 if (curr->softirq_context)
2784 if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
2785 return 0;
2786 }
2787 }
2788 if (!hlock->hardirqs_off) {
2789 if (hlock->read) {
2790 if (!mark_lock(curr, hlock,
2791 LOCK_ENABLED_HARDIRQ_READ))
2792 return 0;
2793 if (curr->softirqs_enabled)
2794 if (!mark_lock(curr, hlock,
2795 LOCK_ENABLED_SOFTIRQ_READ))
2796 return 0;
2797 } else {
2798 if (!mark_lock(curr, hlock,
2799 LOCK_ENABLED_HARDIRQ))
2800 return 0;
2801 if (curr->softirqs_enabled)
2802 if (!mark_lock(curr, hlock,
2803 LOCK_ENABLED_SOFTIRQ))
2804 return 0;
2805 }
2806 }
2807
2808
2809
2810
2811
2812
2813
2814 if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
2815 if (hlock->read) {
2816 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
2817 return 0;
2818 } else {
2819 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
2820 return 0;
2821 }
2822 }
2823
2824 return 1;
2825}
2826
2827static int separate_irq_context(struct task_struct *curr,
2828 struct held_lock *hlock)
2829{
2830 unsigned int depth = curr->lockdep_depth;
2831
2832
2833
2834
2835 hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
2836 curr->softirq_context;
2837 if (depth) {
2838 struct held_lock *prev_hlock;
2839
2840 prev_hlock = curr->held_locks + depth-1;
2841
2842
2843
2844
2845
2846 if (prev_hlock->irq_context != hlock->irq_context)
2847 return 1;
2848 }
2849 return 0;
2850}
2851
2852#else
2853
2854static inline
2855int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2856 enum lock_usage_bit new_bit)
2857{
2858 WARN_ON(1);
2859 return 1;
2860}
2861
2862static inline int mark_irqflags(struct task_struct *curr,
2863 struct held_lock *hlock)
2864{
2865 return 1;
2866}
2867
2868static inline int separate_irq_context(struct task_struct *curr,
2869 struct held_lock *hlock)
2870{
2871 return 0;
2872}
2873
2874void lockdep_trace_alloc(gfp_t gfp_mask)
2875{
2876}
2877
2878#endif
2879
2880
2881
2882
2883static int mark_lock(struct task_struct *curr, struct held_lock *this,
2884 enum lock_usage_bit new_bit)
2885{
2886 unsigned int new_mask = 1 << new_bit, ret = 1;
2887
2888
2889
2890
2891
2892 if (likely(hlock_class(this)->usage_mask & new_mask))
2893 return 1;
2894
2895 if (!graph_lock())
2896 return 0;
2897
2898
2899
2900 if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
2901 graph_unlock();
2902 return 1;
2903 }
2904
2905 hlock_class(this)->usage_mask |= new_mask;
2906
2907 if (!save_trace(hlock_class(this)->usage_traces + new_bit))
2908 return 0;
2909
2910 switch (new_bit) {
2911#define LOCKDEP_STATE(__STATE) \
2912 case LOCK_USED_IN_##__STATE: \
2913 case LOCK_USED_IN_##__STATE##_READ: \
2914 case LOCK_ENABLED_##__STATE: \
2915 case LOCK_ENABLED_##__STATE##_READ:
2916#include "lockdep_states.h"
2917#undef LOCKDEP_STATE
2918 ret = mark_lock_irq(curr, this, new_bit);
2919 if (!ret)
2920 return 0;
2921 break;
2922 case LOCK_USED:
2923 debug_atomic_dec(nr_unused_locks);
2924 break;
2925 default:
2926 if (!debug_locks_off_graph_unlock())
2927 return 0;
2928 WARN_ON(1);
2929 return 0;
2930 }
2931
2932 graph_unlock();
2933
2934
2935
2936
2937 if (ret == 2) {
2938 printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
2939 print_lock(this);
2940 print_irqtrace_events(curr);
2941 dump_stack();
2942 }
2943
2944 return ret;
2945}
2946
2947
2948
2949
2950void lockdep_init_map(struct lockdep_map *lock, const char *name,
2951 struct lock_class_key *key, int subclass)
2952{
2953 int i;
2954
2955 kmemcheck_mark_initialized(lock, sizeof(*lock));
2956
2957 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
2958 lock->class_cache[i] = NULL;
2959
2960#ifdef CONFIG_LOCK_STAT
2961 lock->cpu = raw_smp_processor_id();
2962#endif
2963
2964
2965
2966
2967 if (DEBUG_LOCKS_WARN_ON(!name)) {
2968 lock->name = "NULL";
2969 return;
2970 }
2971
2972 lock->name = name;
2973
2974
2975
2976
2977 if (DEBUG_LOCKS_WARN_ON(!key))
2978 return;
2979
2980
2981
2982 if (!static_obj(key)) {
2983 printk("BUG: key %p not in .data!\n", key);
2984
2985
2986
2987 DEBUG_LOCKS_WARN_ON(1);
2988 return;
2989 }
2990 lock->key = key;
2991
2992 if (unlikely(!debug_locks))
2993 return;
2994
2995 if (subclass)
2996 register_lock_class(lock, subclass, 1);
2997}
2998EXPORT_SYMBOL_GPL(lockdep_init_map);
2999
3000struct lock_class_key __lockdep_no_validate__;
3001EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
3002
3003static int
3004print_lock_nested_lock_not_held(struct task_struct *curr,
3005 struct held_lock *hlock,
3006 unsigned long ip)
3007{
3008 if (!debug_locks_off())
3009 return 0;
3010 if (debug_locks_silent)
3011 return 0;
3012
3013 printk("\n");
3014 printk("==================================\n");
3015 printk("[ BUG: Nested lock was not taken ]\n");
3016 print_kernel_ident();
3017 printk("----------------------------------\n");
3018
3019 printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
3020 print_lock(hlock);
3021
3022 printk("\nbut this task is not holding:\n");
3023 printk("%s\n", hlock->nest_lock->name);
3024
3025 printk("\nstack backtrace:\n");
3026 dump_stack();
3027
3028 printk("\nother info that might help us debug this:\n");
3029 lockdep_print_held_locks(curr);
3030
3031 printk("\nstack backtrace:\n");
3032 dump_stack();
3033
3034 return 0;
3035}
3036
3037static int __lock_is_held(struct lockdep_map *lock);
3038
3039
3040
3041
3042
3043static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
3044 int trylock, int read, int check, int hardirqs_off,
3045 struct lockdep_map *nest_lock, unsigned long ip,
3046 int references)
3047{
3048 struct task_struct *curr = current;
3049 struct lock_class *class = NULL;
3050 struct held_lock *hlock;
3051 unsigned int depth, id;
3052 int chain_head = 0;
3053 int class_idx;
3054 u64 chain_key;
3055
3056 if (!prove_locking)
3057 check = 1;
3058
3059 if (unlikely(!debug_locks))
3060 return 0;
3061
3062
3063
3064
3065
3066
3067 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3068 return 0;
3069
3070 if (lock->key == &__lockdep_no_validate__)
3071 check = 1;
3072
3073 if (subclass < NR_LOCKDEP_CACHING_CLASSES)
3074 class = lock->class_cache[subclass];
3075
3076
3077
3078 if (unlikely(!class)) {
3079 class = register_lock_class(lock, subclass, 0);
3080 if (!class)
3081 return 0;
3082 }
3083 atomic_inc((atomic_t *)&class->ops);
3084 if (very_verbose(class)) {
3085 printk("\nacquire class [%p] %s", class->key, class->name);
3086 if (class->name_version > 1)
3087 printk("#%d", class->name_version);
3088 printk("\n");
3089 dump_stack();
3090 }
3091
3092
3093
3094
3095
3096
3097 depth = curr->lockdep_depth;
3098
3099
3100
3101 if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
3102 return 0;
3103
3104 class_idx = class - lock_classes + 1;
3105
3106 if (depth) {
3107 hlock = curr->held_locks + depth - 1;
3108 if (hlock->class_idx == class_idx && nest_lock) {
3109 if (hlock->references)
3110 hlock->references++;
3111 else
3112 hlock->references = 2;
3113
3114 return 1;
3115 }
3116 }
3117
3118 hlock = curr->held_locks + depth;
3119
3120
3121
3122
3123 if (DEBUG_LOCKS_WARN_ON(!class))
3124 return 0;
3125 hlock->class_idx = class_idx;
3126 hlock->acquire_ip = ip;
3127 hlock->instance = lock;
3128 hlock->nest_lock = nest_lock;
3129 hlock->trylock = trylock;
3130 hlock->read = read;
3131 hlock->check = check;
3132 hlock->hardirqs_off = !!hardirqs_off;
3133 hlock->references = references;
3134#ifdef CONFIG_LOCK_STAT
3135 hlock->waittime_stamp = 0;
3136 hlock->holdtime_stamp = lockstat_clock();
3137#endif
3138
3139 if (check == 2 && !mark_irqflags(curr, hlock))
3140 return 0;
3141
3142
3143 if (!mark_lock(curr, hlock, LOCK_USED))
3144 return 0;
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156 id = class - lock_classes;
3157
3158
3159
3160 if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
3161 return 0;
3162
3163 chain_key = curr->curr_chain_key;
3164 if (!depth) {
3165
3166
3167
3168 if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
3169 return 0;
3170 chain_head = 1;
3171 }
3172
3173 hlock->prev_chain_key = chain_key;
3174 if (separate_irq_context(curr, hlock)) {
3175 chain_key = 0;
3176 chain_head = 1;
3177 }
3178 chain_key = iterate_chain_key(chain_key, id);
3179
3180 if (nest_lock && !__lock_is_held(nest_lock))
3181 return print_lock_nested_lock_not_held(curr, hlock, ip);
3182
3183 if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
3184 return 0;
3185
3186 curr->curr_chain_key = chain_key;
3187 curr->lockdep_depth++;
3188 check_chain_key(curr);
3189#ifdef CONFIG_DEBUG_LOCKDEP
3190 if (unlikely(!debug_locks))
3191 return 0;
3192#endif
3193 if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
3194 debug_locks_off();
3195 print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
3196 printk(KERN_DEBUG "depth: %i max: %lu!\n",
3197 curr->lockdep_depth, MAX_LOCK_DEPTH);
3198
3199 lockdep_print_held_locks(current);
3200 debug_show_all_locks();
3201 dump_stack();
3202
3203 return 0;
3204 }
3205
3206 if (unlikely(curr->lockdep_depth > max_lockdep_depth))
3207 max_lockdep_depth = curr->lockdep_depth;
3208
3209 return 1;
3210}
3211
3212static int
3213print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
3214 unsigned long ip)
3215{
3216 if (!debug_locks_off())
3217 return 0;
3218 if (debug_locks_silent)
3219 return 0;
3220
3221 printk("\n");
3222 printk("=====================================\n");
3223 printk("[ BUG: bad unlock balance detected! ]\n");
3224 print_kernel_ident();
3225 printk("-------------------------------------\n");
3226 printk("%s/%d is trying to release lock (",
3227 curr->comm, task_pid_nr(curr));
3228 print_lockdep_cache(lock);
3229 printk(") at:\n");
3230 print_ip_sym(ip);
3231 printk("but there are no more locks to release!\n");
3232 printk("\nother info that might help us debug this:\n");
3233 lockdep_print_held_locks(curr);
3234
3235 printk("\nstack backtrace:\n");
3236 dump_stack();
3237
3238 return 0;
3239}
3240
3241
3242
3243
3244static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
3245 unsigned long ip)
3246{
3247 if (unlikely(!debug_locks))
3248 return 0;
3249
3250
3251
3252 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3253 return 0;
3254
3255 if (curr->lockdep_depth <= 0)
3256 return print_unlock_imbalance_bug(curr, lock, ip);
3257
3258 return 1;
3259}
3260
3261static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
3262{
3263 if (hlock->instance == lock)
3264 return 1;
3265
3266 if (hlock->references) {
3267 struct lock_class *class = lock->class_cache[0];
3268
3269 if (!class)
3270 class = look_up_lock_class(lock, 0);
3271
3272
3273
3274
3275
3276
3277
3278 if (!class)
3279 return 0;
3280
3281
3282
3283
3284
3285
3286 if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
3287 return 0;
3288
3289 if (hlock->class_idx == class - lock_classes + 1)
3290 return 1;
3291 }
3292
3293 return 0;
3294}
3295
3296static int
3297__lock_set_class(struct lockdep_map *lock, const char *name,
3298 struct lock_class_key *key, unsigned int subclass,
3299 unsigned long ip)
3300{
3301 struct task_struct *curr = current;
3302 struct held_lock *hlock, *prev_hlock;
3303 struct lock_class *class;
3304 unsigned int depth;
3305 int i;
3306
3307 depth = curr->lockdep_depth;
3308
3309
3310
3311
3312 if (DEBUG_LOCKS_WARN_ON(!depth))
3313 return 0;
3314
3315 prev_hlock = NULL;
3316 for (i = depth-1; i >= 0; i--) {
3317 hlock = curr->held_locks + i;
3318
3319
3320
3321 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3322 break;
3323 if (match_held_lock(hlock, lock))
3324 goto found_it;
3325 prev_hlock = hlock;
3326 }
3327 return print_unlock_imbalance_bug(curr, lock, ip);
3328
3329found_it:
3330 lockdep_init_map(lock, name, key, 0);
3331 class = register_lock_class(lock, subclass, 0);
3332 hlock->class_idx = class - lock_classes + 1;
3333
3334 curr->lockdep_depth = i;
3335 curr->curr_chain_key = hlock->prev_chain_key;
3336
3337 for (; i < depth; i++) {
3338 hlock = curr->held_locks + i;
3339 if (!__lock_acquire(hlock->instance,
3340 hlock_class(hlock)->subclass, hlock->trylock,
3341 hlock->read, hlock->check, hlock->hardirqs_off,
3342 hlock->nest_lock, hlock->acquire_ip,
3343 hlock->references))
3344 return 0;
3345 }
3346
3347
3348
3349
3350
3351 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
3352 return 0;
3353 return 1;
3354}
3355
3356
3357
3358
3359
3360
3361
3362static int
3363lock_release_non_nested(struct task_struct *curr,
3364 struct lockdep_map *lock, unsigned long ip)
3365{
3366 struct held_lock *hlock, *prev_hlock;
3367 unsigned int depth;
3368 int i;
3369
3370
3371
3372
3373
3374 depth = curr->lockdep_depth;
3375
3376
3377
3378
3379 if (DEBUG_LOCKS_WARN_ON(!depth))
3380 return 0;
3381
3382 prev_hlock = NULL;
3383 for (i = depth-1; i >= 0; i--) {
3384 hlock = curr->held_locks + i;
3385
3386
3387
3388 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3389 break;
3390 if (match_held_lock(hlock, lock))
3391 goto found_it;
3392 prev_hlock = hlock;
3393 }
3394 return print_unlock_imbalance_bug(curr, lock, ip);
3395
3396found_it:
3397 if (hlock->instance == lock)
3398 lock_release_holdtime(hlock);
3399
3400 if (hlock->references) {
3401 hlock->references--;
3402 if (hlock->references) {
3403
3404
3405
3406
3407
3408 return 1;
3409 }
3410 }
3411
3412
3413
3414
3415
3416
3417
3418 curr->lockdep_depth = i;
3419 curr->curr_chain_key = hlock->prev_chain_key;
3420
3421 for (i++; i < depth; i++) {
3422 hlock = curr->held_locks + i;
3423 if (!__lock_acquire(hlock->instance,
3424 hlock_class(hlock)->subclass, hlock->trylock,
3425 hlock->read, hlock->check, hlock->hardirqs_off,
3426 hlock->nest_lock, hlock->acquire_ip,
3427 hlock->references))
3428 return 0;
3429 }
3430
3431
3432
3433
3434
3435 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
3436 return 0;
3437 return 1;
3438}
3439
3440
3441
3442
3443
3444
3445
3446static int lock_release_nested(struct task_struct *curr,
3447 struct lockdep_map *lock, unsigned long ip)
3448{
3449 struct held_lock *hlock;
3450 unsigned int depth;
3451
3452
3453
3454
3455 depth = curr->lockdep_depth - 1;
3456 hlock = curr->held_locks + depth;
3457
3458
3459
3460
3461 if (hlock->instance != lock || hlock->references)
3462 return lock_release_non_nested(curr, lock, ip);
3463 curr->lockdep_depth--;
3464
3465
3466
3467
3468 if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
3469 return 0;
3470
3471 curr->curr_chain_key = hlock->prev_chain_key;
3472
3473 lock_release_holdtime(hlock);
3474
3475#ifdef CONFIG_DEBUG_LOCKDEP
3476 hlock->prev_chain_key = 0;
3477 hlock->class_idx = 0;
3478 hlock->acquire_ip = 0;
3479 hlock->irq_context = 0;
3480#endif
3481 return 1;
3482}
3483
3484
3485
3486
3487
3488
3489
3490static void
3491__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
3492{
3493 struct task_struct *curr = current;
3494
3495 if (!check_unlock(curr, lock, ip))
3496 return;
3497
3498 if (nested) {
3499 if (!lock_release_nested(curr, lock, ip))
3500 return;
3501 } else {
3502 if (!lock_release_non_nested(curr, lock, ip))
3503 return;
3504 }
3505
3506 check_chain_key(curr);
3507}
3508
3509static int __lock_is_held(struct lockdep_map *lock)
3510{
3511 struct task_struct *curr = current;
3512 int i;
3513
3514 for (i = 0; i < curr->lockdep_depth; i++) {
3515 struct held_lock *hlock = curr->held_locks + i;
3516
3517 if (match_held_lock(hlock, lock))
3518 return 1;
3519 }
3520
3521 return 0;
3522}
3523
3524
3525
3526
3527static void check_flags(unsigned long flags)
3528{
3529#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
3530 defined(CONFIG_TRACE_IRQFLAGS)
3531 if (!debug_locks)
3532 return;
3533
3534 if (irqs_disabled_flags(flags)) {
3535 if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
3536 printk("possible reason: unannotated irqs-off.\n");
3537 }
3538 } else {
3539 if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
3540 printk("possible reason: unannotated irqs-on.\n");
3541 }
3542 }
3543
3544
3545
3546
3547
3548
3549 if (!hardirq_count()) {
3550 if (softirq_count()) {
3551
3552 DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
3553 } else {
3554
3555 DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
3556 }
3557 }
3558
3559 if (!debug_locks)
3560 print_irqtrace_events(current);
3561#endif
3562}
3563
3564void lock_set_class(struct lockdep_map *lock, const char *name,
3565 struct lock_class_key *key, unsigned int subclass,
3566 unsigned long ip)
3567{
3568 unsigned long flags;
3569
3570 if (unlikely(current->lockdep_recursion))
3571 return;
3572
3573 raw_local_irq_save(flags);
3574 current->lockdep_recursion = 1;
3575 check_flags(flags);
3576 if (__lock_set_class(lock, name, key, subclass, ip))
3577 check_chain_key(current);
3578 current->lockdep_recursion = 0;
3579 raw_local_irq_restore(flags);
3580}
3581EXPORT_SYMBOL_GPL(lock_set_class);
3582
3583
3584
3585
3586
3587void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
3588 int trylock, int read, int check,
3589 struct lockdep_map *nest_lock, unsigned long ip)
3590{
3591 unsigned long flags;
3592
3593 if (unlikely(current->lockdep_recursion))
3594 return;
3595
3596 raw_local_irq_save(flags);
3597 check_flags(flags);
3598
3599 current->lockdep_recursion = 1;
3600 trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
3601 __lock_acquire(lock, subclass, trylock, read, check,
3602 irqs_disabled_flags(flags), nest_lock, ip, 0);
3603 current->lockdep_recursion = 0;
3604 raw_local_irq_restore(flags);
3605}
3606EXPORT_SYMBOL_GPL(lock_acquire);
3607
3608void lock_release(struct lockdep_map *lock, int nested,
3609 unsigned long ip)
3610{
3611 unsigned long flags;
3612
3613 if (unlikely(current->lockdep_recursion))
3614 return;
3615
3616 raw_local_irq_save(flags);
3617 check_flags(flags);
3618 current->lockdep_recursion = 1;
3619 trace_lock_release(lock, ip);
3620 __lock_release(lock, nested, ip);
3621 current->lockdep_recursion = 0;
3622 raw_local_irq_restore(flags);
3623}
3624EXPORT_SYMBOL_GPL(lock_release);
3625
3626int lock_is_held(struct lockdep_map *lock)
3627{
3628 unsigned long flags;
3629 int ret = 0;
3630
3631 if (unlikely(current->lockdep_recursion))
3632 return 1;
3633
3634 raw_local_irq_save(flags);
3635 check_flags(flags);
3636
3637 current->lockdep_recursion = 1;
3638 ret = __lock_is_held(lock);
3639 current->lockdep_recursion = 0;
3640 raw_local_irq_restore(flags);
3641
3642 return ret;
3643}
3644EXPORT_SYMBOL_GPL(lock_is_held);
3645
3646void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
3647{
3648 current->lockdep_reclaim_gfp = gfp_mask;
3649}
3650
3651void lockdep_clear_current_reclaim_state(void)
3652{
3653 current->lockdep_reclaim_gfp = 0;
3654}
3655
3656#ifdef CONFIG_LOCK_STAT
3657static int
3658print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
3659 unsigned long ip)
3660{
3661 if (!debug_locks_off())
3662 return 0;
3663 if (debug_locks_silent)
3664 return 0;
3665
3666 printk("\n");
3667 printk("=================================\n");
3668 printk("[ BUG: bad contention detected! ]\n");
3669 print_kernel_ident();
3670 printk("---------------------------------\n");
3671 printk("%s/%d is trying to contend lock (",
3672 curr->comm, task_pid_nr(curr));
3673 print_lockdep_cache(lock);
3674 printk(") at:\n");
3675 print_ip_sym(ip);
3676 printk("but there are no locks held!\n");
3677 printk("\nother info that might help us debug this:\n");
3678 lockdep_print_held_locks(curr);
3679
3680 printk("\nstack backtrace:\n");
3681 dump_stack();
3682
3683 return 0;
3684}
3685
3686static void
3687__lock_contended(struct lockdep_map *lock, unsigned long ip)
3688{
3689 struct task_struct *curr = current;
3690 struct held_lock *hlock, *prev_hlock;
3691 struct lock_class_stats *stats;
3692 unsigned int depth;
3693 int i, contention_point, contending_point;
3694
3695 depth = curr->lockdep_depth;
3696
3697
3698
3699
3700 if (DEBUG_LOCKS_WARN_ON(!depth))
3701 return;
3702
3703 prev_hlock = NULL;
3704 for (i = depth-1; i >= 0; i--) {
3705 hlock = curr->held_locks + i;
3706
3707
3708
3709 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3710 break;
3711 if (match_held_lock(hlock, lock))
3712 goto found_it;
3713 prev_hlock = hlock;
3714 }
3715 print_lock_contention_bug(curr, lock, ip);
3716 return;
3717
3718found_it:
3719 if (hlock->instance != lock)
3720 return;
3721
3722 hlock->waittime_stamp = lockstat_clock();
3723
3724 contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
3725 contending_point = lock_point(hlock_class(hlock)->contending_point,
3726 lock->ip);
3727
3728 stats = get_lock_stats(hlock_class(hlock));
3729 if (contention_point < LOCKSTAT_POINTS)
3730 stats->contention_point[contention_point]++;
3731 if (contending_point < LOCKSTAT_POINTS)
3732 stats->contending_point[contending_point]++;
3733 if (lock->cpu != smp_processor_id())
3734 stats->bounces[bounce_contended + !!hlock->read]++;
3735 put_lock_stats(stats);
3736}
3737
3738static void
3739__lock_acquired(struct lockdep_map *lock, unsigned long ip)
3740{
3741 struct task_struct *curr = current;
3742 struct held_lock *hlock, *prev_hlock;
3743 struct lock_class_stats *stats;
3744 unsigned int depth;
3745 u64 now, waittime = 0;
3746 int i, cpu;
3747
3748 depth = curr->lockdep_depth;
3749
3750
3751
3752
3753 if (DEBUG_LOCKS_WARN_ON(!depth))
3754 return;
3755
3756 prev_hlock = NULL;
3757 for (i = depth-1; i >= 0; i--) {
3758 hlock = curr->held_locks + i;
3759
3760
3761
3762 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3763 break;
3764 if (match_held_lock(hlock, lock))
3765 goto found_it;
3766 prev_hlock = hlock;
3767 }
3768 print_lock_contention_bug(curr, lock, _RET_IP_);
3769 return;
3770
3771found_it:
3772 if (hlock->instance != lock)
3773 return;
3774
3775 cpu = smp_processor_id();
3776 if (hlock->waittime_stamp) {
3777 now = lockstat_clock();
3778 waittime = now - hlock->waittime_stamp;
3779 hlock->holdtime_stamp = now;
3780 }
3781
3782 trace_lock_acquired(lock, ip);
3783
3784 stats = get_lock_stats(hlock_class(hlock));
3785 if (waittime) {
3786 if (hlock->read)
3787 lock_time_inc(&stats->read_waittime, waittime);
3788 else
3789 lock_time_inc(&stats->write_waittime, waittime);
3790 }
3791 if (lock->cpu != cpu)
3792 stats->bounces[bounce_acquired + !!hlock->read]++;
3793 put_lock_stats(stats);
3794
3795 lock->cpu = cpu;
3796 lock->ip = ip;
3797}
3798
3799void lock_contended(struct lockdep_map *lock, unsigned long ip)
3800{
3801 unsigned long flags;
3802
3803 if (unlikely(!lock_stat))
3804 return;
3805
3806 if (unlikely(current->lockdep_recursion))
3807 return;
3808
3809 raw_local_irq_save(flags);
3810 check_flags(flags);
3811 current->lockdep_recursion = 1;
3812 trace_lock_contended(lock, ip);
3813 __lock_contended(lock, ip);
3814 current->lockdep_recursion = 0;
3815 raw_local_irq_restore(flags);
3816}
3817EXPORT_SYMBOL_GPL(lock_contended);
3818
3819void lock_acquired(struct lockdep_map *lock, unsigned long ip)
3820{
3821 unsigned long flags;
3822
3823 if (unlikely(!lock_stat))
3824 return;
3825
3826 if (unlikely(current->lockdep_recursion))
3827 return;
3828
3829 raw_local_irq_save(flags);
3830 check_flags(flags);
3831 current->lockdep_recursion = 1;
3832 __lock_acquired(lock, ip);
3833 current->lockdep_recursion = 0;
3834 raw_local_irq_restore(flags);
3835}
3836EXPORT_SYMBOL_GPL(lock_acquired);
3837#endif
3838
3839
3840
3841
3842
3843
3844void lockdep_reset(void)
3845{
3846 unsigned long flags;
3847 int i;
3848
3849 raw_local_irq_save(flags);
3850 current->curr_chain_key = 0;
3851 current->lockdep_depth = 0;
3852 current->lockdep_recursion = 0;
3853 memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
3854 nr_hardirq_chains = 0;
3855 nr_softirq_chains = 0;
3856 nr_process_chains = 0;
3857 debug_locks = 1;
3858 for (i = 0; i < CHAINHASH_SIZE; i++)
3859 INIT_LIST_HEAD(chainhash_table + i);
3860 raw_local_irq_restore(flags);
3861}
3862
3863static void zap_class(struct lock_class *class)
3864{
3865 int i;
3866
3867
3868
3869
3870
3871 for (i = 0; i < nr_list_entries; i++) {
3872 if (list_entries[i].class == class)
3873 list_del_rcu(&list_entries[i].entry);
3874 }
3875
3876
3877
3878 list_del_rcu(&class->hash_entry);
3879 list_del_rcu(&class->lock_entry);
3880
3881 class->key = NULL;
3882}
3883
3884static inline int within(const void *addr, void *start, unsigned long size)
3885{
3886 return addr >= start && addr < start + size;
3887}
3888
3889void lockdep_free_key_range(void *start, unsigned long size)
3890{
3891 struct lock_class *class, *next;
3892 struct list_head *head;
3893 unsigned long flags;
3894 int i;
3895 int locked;
3896
3897 raw_local_irq_save(flags);
3898 locked = graph_lock();
3899
3900
3901
3902
3903 for (i = 0; i < CLASSHASH_SIZE; i++) {
3904 head = classhash_table + i;
3905 if (list_empty(head))
3906 continue;
3907 list_for_each_entry_safe(class, next, head, hash_entry) {
3908 if (within(class->key, start, size))
3909 zap_class(class);
3910 else if (within(class->name, start, size))
3911 zap_class(class);
3912 }
3913 }
3914
3915 if (locked)
3916 graph_unlock();
3917 raw_local_irq_restore(flags);
3918}
3919
3920void lockdep_reset_lock(struct lockdep_map *lock)
3921{
3922 struct lock_class *class, *next;
3923 struct list_head *head;
3924 unsigned long flags;
3925 int i, j;
3926 int locked;
3927
3928 raw_local_irq_save(flags);
3929
3930
3931
3932
3933 for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
3934
3935
3936
3937 class = look_up_lock_class(lock, j);
3938 if (class)
3939 zap_class(class);
3940 }
3941
3942
3943
3944
3945 locked = graph_lock();
3946 for (i = 0; i < CLASSHASH_SIZE; i++) {
3947 head = classhash_table + i;
3948 if (list_empty(head))
3949 continue;
3950 list_for_each_entry_safe(class, next, head, hash_entry) {
3951 int match = 0;
3952
3953 for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
3954 match |= class == lock->class_cache[j];
3955
3956 if (unlikely(match)) {
3957 if (debug_locks_off_graph_unlock()) {
3958
3959
3960
3961 WARN_ON(1);
3962 }
3963 goto out_restore;
3964 }
3965 }
3966 }
3967 if (locked)
3968 graph_unlock();
3969
3970out_restore:
3971 raw_local_irq_restore(flags);
3972}
3973
3974void lockdep_init(void)
3975{
3976 int i;
3977
3978
3979
3980
3981
3982
3983
3984 if (lockdep_initialized)
3985 return;
3986
3987 for (i = 0; i < CLASSHASH_SIZE; i++)
3988 INIT_LIST_HEAD(classhash_table + i);
3989
3990 for (i = 0; i < CHAINHASH_SIZE; i++)
3991 INIT_LIST_HEAD(chainhash_table + i);
3992
3993 lockdep_initialized = 1;
3994}
3995
3996void __init lockdep_info(void)
3997{
3998 printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
3999
4000 printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
4001 printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
4002 printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
4003 printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
4004 printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
4005 printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
4006 printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
4007
4008 printk(" memory used by lock dependency info: %lu kB\n",
4009 (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
4010 sizeof(struct list_head) * CLASSHASH_SIZE +
4011 sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
4012 sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
4013 sizeof(struct list_head) * CHAINHASH_SIZE
4014#ifdef CONFIG_PROVE_LOCKING
4015 + sizeof(struct circular_queue)
4016#endif
4017 ) / 1024
4018 );
4019
4020 printk(" per task-struct memory footprint: %lu bytes\n",
4021 sizeof(struct held_lock) * MAX_LOCK_DEPTH);
4022
4023#ifdef CONFIG_DEBUG_LOCKDEP
4024 if (lockdep_init_error) {
4025 printk("WARNING: lockdep init error! lock-%s was acquired"
4026 "before lockdep_init\n", lock_init_error);
4027 printk("Call stack leading to lockdep invocation was:\n");
4028 print_stack_trace(&lockdep_init_trace, 0);
4029 }
4030#endif
4031}
4032
4033static void
4034print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
4035 const void *mem_to, struct held_lock *hlock)
4036{
4037 if (!debug_locks_off())
4038 return;
4039 if (debug_locks_silent)
4040 return;
4041
4042 printk("\n");
4043 printk("=========================\n");
4044 printk("[ BUG: held lock freed! ]\n");
4045 print_kernel_ident();
4046 printk("-------------------------\n");
4047 printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
4048 curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
4049 print_lock(hlock);
4050 lockdep_print_held_locks(curr);
4051
4052 printk("\nstack backtrace:\n");
4053 dump_stack();
4054}
4055
4056static inline int not_in_range(const void* mem_from, unsigned long mem_len,
4057 const void* lock_from, unsigned long lock_len)
4058{
4059 return lock_from + lock_len <= mem_from ||
4060 mem_from + mem_len <= lock_from;
4061}
4062
4063
4064
4065
4066
4067
4068void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
4069{
4070 struct task_struct *curr = current;
4071 struct held_lock *hlock;
4072 unsigned long flags;
4073 int i;
4074
4075 if (unlikely(!debug_locks))
4076 return;
4077
4078 local_irq_save(flags);
4079 for (i = 0; i < curr->lockdep_depth; i++) {
4080 hlock = curr->held_locks + i;
4081
4082 if (not_in_range(mem_from, mem_len, hlock->instance,
4083 sizeof(*hlock->instance)))
4084 continue;
4085
4086 print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
4087 break;
4088 }
4089 local_irq_restore(flags);
4090}
4091EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
4092
4093static void print_held_locks_bug(void)
4094{
4095 if (!debug_locks_off())
4096 return;
4097 if (debug_locks_silent)
4098 return;
4099
4100 printk("\n");
4101 printk("=====================================\n");
4102 printk("[ BUG: %s/%d still has locks held! ]\n",
4103 current->comm, task_pid_nr(current));
4104 print_kernel_ident();
4105 printk("-------------------------------------\n");
4106 lockdep_print_held_locks(current);
4107 printk("\nstack backtrace:\n");
4108 dump_stack();
4109}
4110
4111void debug_check_no_locks_held(void)
4112{
4113 if (unlikely(current->lockdep_depth > 0))
4114 print_held_locks_bug();
4115}
4116EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
4117
4118void debug_show_all_locks(void)
4119{
4120 struct task_struct *g, *p;
4121 int count = 10;
4122 int unlock = 1;
4123
4124 if (unlikely(!debug_locks)) {
4125 printk("INFO: lockdep is turned off.\n");
4126 return;
4127 }
4128 printk("\nShowing all locks held in the system:\n");
4129
4130
4131
4132
4133
4134
4135
4136retry:
4137 if (!read_trylock(&tasklist_lock)) {
4138 if (count == 10)
4139 printk("hm, tasklist_lock locked, retrying... ");
4140 if (count) {
4141 count--;
4142 printk(" #%d", 10-count);
4143 mdelay(200);
4144 goto retry;
4145 }
4146 printk(" ignoring it.\n");
4147 unlock = 0;
4148 } else {
4149 if (count != 10)
4150 printk(KERN_CONT " locked it.\n");
4151 }
4152
4153 do_each_thread(g, p) {
4154
4155
4156
4157
4158
4159 if (p->state == TASK_RUNNING && p != current)
4160 continue;
4161 if (p->lockdep_depth)
4162 lockdep_print_held_locks(p);
4163 if (!unlock)
4164 if (read_trylock(&tasklist_lock))
4165 unlock = 1;
4166 } while_each_thread(g, p);
4167
4168 printk("\n");
4169 printk("=============================================\n\n");
4170
4171 if (unlock)
4172 read_unlock(&tasklist_lock);
4173}
4174EXPORT_SYMBOL_GPL(debug_show_all_locks);
4175
4176
4177
4178
4179
4180void debug_show_held_locks(struct task_struct *task)
4181{
4182 if (unlikely(!debug_locks)) {
4183 printk("INFO: lockdep is turned off.\n");
4184 return;
4185 }
4186 lockdep_print_held_locks(task);
4187}
4188EXPORT_SYMBOL_GPL(debug_show_held_locks);
4189
4190void lockdep_sys_exit(void)
4191{
4192 struct task_struct *curr = current;
4193
4194 if (unlikely(curr->lockdep_depth)) {
4195 if (!debug_locks_off())
4196 return;
4197 printk("\n");
4198 printk("================================================\n");
4199 printk("[ BUG: lock held when returning to user space! ]\n");
4200 print_kernel_ident();
4201 printk("------------------------------------------------\n");
4202 printk("%s/%d is leaving the kernel with locks still held!\n",
4203 curr->comm, curr->pid);
4204 lockdep_print_held_locks(curr);
4205 }
4206}
4207
4208void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
4209{
4210 struct task_struct *curr = current;
4211
4212#ifndef CONFIG_PROVE_RCU_REPEATEDLY
4213 if (!debug_locks_off())
4214 return;
4215#endif
4216
4217 printk("\n");
4218 printk("===============================\n");
4219 printk("[ INFO: suspicious RCU usage. ]\n");
4220 print_kernel_ident();
4221 printk("-------------------------------\n");
4222 printk("%s:%d %s!\n", file, line, s);
4223 printk("\nother info that might help us debug this:\n\n");
4224 printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
4225 !rcu_lockdep_current_cpu_online()
4226 ? "RCU used illegally from offline CPU!\n"
4227 : rcu_is_cpu_idle()
4228 ? "RCU used illegally from idle CPU!\n"
4229 : "",
4230 rcu_scheduler_active, debug_locks);
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250 if (rcu_is_cpu_idle())
4251 printk("RCU used illegally from extended quiescent state!\n");
4252
4253 lockdep_print_held_locks(curr);
4254 printk("\nstack backtrace:\n");
4255 dump_stack();
4256}
4257EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
4258