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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
126unsigned long nr_list_entries;
127static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
128
129
130
131
132
133
134
135unsigned long nr_lock_classes;
136static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
137
138static inline struct lock_class *hlock_class(struct held_lock *hlock)
139{
140 if (!hlock->class_idx) {
141
142
143
144 DEBUG_LOCKS_WARN_ON(1);
145 return NULL;
146 }
147 return lock_classes + hlock->class_idx - 1;
148}
149
150#ifdef CONFIG_LOCK_STAT
151static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats);
152
153static inline u64 lockstat_clock(void)
154{
155 return local_clock();
156}
157
158static int lock_point(unsigned long points[], unsigned long ip)
159{
160 int i;
161
162 for (i = 0; i < LOCKSTAT_POINTS; i++) {
163 if (points[i] == 0) {
164 points[i] = ip;
165 break;
166 }
167 if (points[i] == ip)
168 break;
169 }
170
171 return i;
172}
173
174static void lock_time_inc(struct lock_time *lt, u64 time)
175{
176 if (time > lt->max)
177 lt->max = time;
178
179 if (time < lt->min || !lt->nr)
180 lt->min = time;
181
182 lt->total += time;
183 lt->nr++;
184}
185
186static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
187{
188 if (!src->nr)
189 return;
190
191 if (src->max > dst->max)
192 dst->max = src->max;
193
194 if (src->min < dst->min || !dst->nr)
195 dst->min = src->min;
196
197 dst->total += src->total;
198 dst->nr += src->nr;
199}
200
201struct lock_class_stats lock_stats(struct lock_class *class)
202{
203 struct lock_class_stats stats;
204 int cpu, i;
205
206 memset(&stats, 0, sizeof(struct lock_class_stats));
207 for_each_possible_cpu(cpu) {
208 struct lock_class_stats *pcs =
209 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
210
211 for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
212 stats.contention_point[i] += pcs->contention_point[i];
213
214 for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
215 stats.contending_point[i] += pcs->contending_point[i];
216
217 lock_time_add(&pcs->read_waittime, &stats.read_waittime);
218 lock_time_add(&pcs->write_waittime, &stats.write_waittime);
219
220 lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
221 lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
222
223 for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
224 stats.bounces[i] += pcs->bounces[i];
225 }
226
227 return stats;
228}
229
230void clear_lock_stats(struct lock_class *class)
231{
232 int cpu;
233
234 for_each_possible_cpu(cpu) {
235 struct lock_class_stats *cpu_stats =
236 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
237
238 memset(cpu_stats, 0, sizeof(struct lock_class_stats));
239 }
240 memset(class->contention_point, 0, sizeof(class->contention_point));
241 memset(class->contending_point, 0, sizeof(class->contending_point));
242}
243
244static struct lock_class_stats *get_lock_stats(struct lock_class *class)
245{
246 return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
247}
248
249static void put_lock_stats(struct lock_class_stats *stats)
250{
251 put_cpu_var(cpu_lock_stats);
252}
253
254static void lock_release_holdtime(struct held_lock *hlock)
255{
256 struct lock_class_stats *stats;
257 u64 holdtime;
258
259 if (!lock_stat)
260 return;
261
262 holdtime = lockstat_clock() - hlock->holdtime_stamp;
263
264 stats = get_lock_stats(hlock_class(hlock));
265 if (hlock->read)
266 lock_time_inc(&stats->read_holdtime, holdtime);
267 else
268 lock_time_inc(&stats->write_holdtime, holdtime);
269 put_lock_stats(stats);
270}
271#else
272static inline void lock_release_holdtime(struct held_lock *hlock)
273{
274}
275#endif
276
277
278
279
280
281
282LIST_HEAD(all_lock_classes);
283
284
285
286
287#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
288#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
289#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
290#define classhashentry(key) (classhash_table + __classhashfn((key)))
291
292static struct hlist_head classhash_table[CLASSHASH_SIZE];
293
294
295
296
297
298#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
299#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
300#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
301#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
302
303static struct hlist_head chainhash_table[CHAINHASH_SIZE];
304
305
306
307
308
309
310
311#define iterate_chain_key(key1, key2) \
312 (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
313 ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
314 (key2))
315
316void lockdep_off(void)
317{
318 current->lockdep_recursion++;
319}
320EXPORT_SYMBOL(lockdep_off);
321
322void lockdep_on(void)
323{
324 current->lockdep_recursion--;
325}
326EXPORT_SYMBOL(lockdep_on);
327
328
329
330
331
332#define VERBOSE 0
333#define VERY_VERBOSE 0
334
335#if VERBOSE
336# define HARDIRQ_VERBOSE 1
337# define SOFTIRQ_VERBOSE 1
338# define RECLAIM_VERBOSE 1
339#else
340# define HARDIRQ_VERBOSE 0
341# define SOFTIRQ_VERBOSE 0
342# define RECLAIM_VERBOSE 0
343#endif
344
345#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
346
347
348
349static int class_filter(struct lock_class *class)
350{
351#if 0
352
353 if (class->name_version == 1 &&
354 !strcmp(class->name, "lockname"))
355 return 1;
356 if (class->name_version == 1 &&
357 !strcmp(class->name, "&struct->lockfield"))
358 return 1;
359#endif
360
361 return 0;
362}
363#endif
364
365static int verbose(struct lock_class *class)
366{
367#if VERBOSE
368 return class_filter(class);
369#endif
370 return 0;
371}
372
373
374
375
376
377unsigned long nr_stack_trace_entries;
378static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
379
380static void print_lockdep_off(const char *bug_msg)
381{
382 printk(KERN_DEBUG "%s\n", bug_msg);
383 printk(KERN_DEBUG "turning off the locking correctness validator.\n");
384#ifdef CONFIG_LOCK_STAT
385 printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
386#endif
387}
388
389static int save_trace(struct stack_trace *trace)
390{
391 trace->nr_entries = 0;
392 trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
393 trace->entries = stack_trace + nr_stack_trace_entries;
394
395 trace->skip = 3;
396
397 save_stack_trace(trace);
398
399
400
401
402
403
404
405
406 if (trace->nr_entries != 0 &&
407 trace->entries[trace->nr_entries-1] == ULONG_MAX)
408 trace->nr_entries--;
409
410 trace->max_entries = trace->nr_entries;
411
412 nr_stack_trace_entries += trace->nr_entries;
413
414 if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
415 if (!debug_locks_off_graph_unlock())
416 return 0;
417
418 print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
419 dump_stack();
420
421 return 0;
422 }
423
424 return 1;
425}
426
427unsigned int nr_hardirq_chains;
428unsigned int nr_softirq_chains;
429unsigned int nr_process_chains;
430unsigned int max_lockdep_depth;
431
432#ifdef CONFIG_DEBUG_LOCKDEP
433
434
435
436DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
437#endif
438
439
440
441
442
443#define __USAGE(__STATE) \
444 [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
445 [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
446 [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
447 [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
448
449static const char *usage_str[] =
450{
451#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
452#include "lockdep_states.h"
453#undef LOCKDEP_STATE
454 [LOCK_USED] = "INITIAL USE",
455};
456
457const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
458{
459 return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
460}
461
462static inline unsigned long lock_flag(enum lock_usage_bit bit)
463{
464 return 1UL << bit;
465}
466
467static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
468{
469 char c = '.';
470
471 if (class->usage_mask & lock_flag(bit + 2))
472 c = '+';
473 if (class->usage_mask & lock_flag(bit)) {
474 c = '-';
475 if (class->usage_mask & lock_flag(bit + 2))
476 c = '?';
477 }
478
479 return c;
480}
481
482void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
483{
484 int i = 0;
485
486#define LOCKDEP_STATE(__STATE) \
487 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
488 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
489#include "lockdep_states.h"
490#undef LOCKDEP_STATE
491
492 usage[i] = '\0';
493}
494
495static void __print_lock_name(struct lock_class *class)
496{
497 char str[KSYM_NAME_LEN];
498 const char *name;
499
500 name = class->name;
501 if (!name) {
502 name = __get_key_name(class->key, str);
503 printk("%s", name);
504 } else {
505 printk("%s", name);
506 if (class->name_version > 1)
507 printk("#%d", class->name_version);
508 if (class->subclass)
509 printk("/%d", class->subclass);
510 }
511}
512
513static void print_lock_name(struct lock_class *class)
514{
515 char usage[LOCK_USAGE_CHARS];
516
517 get_usage_chars(class, usage);
518
519 printk(" (");
520 __print_lock_name(class);
521 printk("){%s}", usage);
522}
523
524static void print_lockdep_cache(struct lockdep_map *lock)
525{
526 const char *name;
527 char str[KSYM_NAME_LEN];
528
529 name = lock->name;
530 if (!name)
531 name = __get_key_name(lock->key->subkeys, str);
532
533 printk("%s", name);
534}
535
536static void print_lock(struct held_lock *hlock)
537{
538
539
540
541
542 unsigned int class_idx = hlock->class_idx;
543
544
545 barrier();
546
547 if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) {
548 printk("<RELEASED>\n");
549 return;
550 }
551
552 print_lock_name(lock_classes + class_idx - 1);
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
593#ifdef __KERNEL__
594static int static_obj(void *obj)
595{
596 unsigned long start = (unsigned long) &_stext,
597 end = (unsigned long) &_end,
598 addr = (unsigned long) obj;
599
600
601
602
603 if ((addr >= start) && (addr < end))
604 return 1;
605
606 if (arch_is_kernel_data(addr))
607 return 1;
608
609
610
611
612 if (is_kernel_percpu_address(addr))
613 return 1;
614
615
616
617
618 return is_module_address(addr) || is_module_percpu_address(addr);
619}
620#endif
621
622
623
624
625
626static int count_matching_names(struct lock_class *new_class)
627{
628 struct lock_class *class;
629 int count = 0;
630
631 if (!new_class->name)
632 return 0;
633
634 list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) {
635 if (new_class->key - new_class->subclass == class->key)
636 return class->name_version;
637 if (class->name && !strcmp(class->name, new_class->name))
638 count = max(count, class->name_version);
639 }
640
641 return count + 1;
642}
643
644
645
646
647
648
649static inline struct lock_class *
650look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
651{
652 struct lockdep_subclass_key *key;
653 struct hlist_head *hash_head;
654 struct lock_class *class;
655
656 if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
657 debug_locks_off();
658 printk(KERN_ERR
659 "BUG: looking up invalid subclass: %u\n", subclass);
660 printk(KERN_ERR
661 "turning off the locking correctness validator.\n");
662 dump_stack();
663 return NULL;
664 }
665
666
667
668
669
670 if (unlikely(!lock->key))
671 lock->key = (void *)lock;
672
673
674
675
676
677
678
679 BUILD_BUG_ON(sizeof(struct lock_class_key) >
680 sizeof(struct lockdep_map));
681
682 key = lock->key->subkeys + subclass;
683
684 hash_head = classhashentry(key);
685
686
687
688
689 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
690 return NULL;
691
692 hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
693 if (class->key == key) {
694
695
696
697
698 WARN_ON_ONCE(class->name != lock->name);
699 return class;
700 }
701 }
702
703 return NULL;
704}
705
706
707
708
709
710
711static inline struct lock_class *
712register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
713{
714 struct lockdep_subclass_key *key;
715 struct hlist_head *hash_head;
716 struct lock_class *class;
717
718 DEBUG_LOCKS_WARN_ON(!irqs_disabled());
719
720 class = look_up_lock_class(lock, subclass);
721 if (likely(class))
722 goto out_set_class_cache;
723
724
725
726
727 if (!static_obj(lock->key)) {
728 debug_locks_off();
729 printk("INFO: trying to register non-static key.\n");
730 printk("the code is fine but needs lockdep annotation.\n");
731 printk("turning off the locking correctness validator.\n");
732 dump_stack();
733
734 return NULL;
735 }
736
737 key = lock->key->subkeys + subclass;
738 hash_head = classhashentry(key);
739
740 if (!graph_lock()) {
741 return NULL;
742 }
743
744
745
746
747 hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
748 if (class->key == key)
749 goto out_unlock_set;
750 }
751
752
753
754
755
756 if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
757 if (!debug_locks_off_graph_unlock()) {
758 return NULL;
759 }
760
761 print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
762 dump_stack();
763 return NULL;
764 }
765 class = lock_classes + nr_lock_classes++;
766 debug_atomic_inc(nr_unused_locks);
767 class->key = key;
768 class->name = lock->name;
769 class->subclass = subclass;
770 INIT_LIST_HEAD(&class->lock_entry);
771 INIT_LIST_HEAD(&class->locks_before);
772 INIT_LIST_HEAD(&class->locks_after);
773 class->name_version = count_matching_names(class);
774
775
776
777
778 hlist_add_head_rcu(&class->hash_entry, hash_head);
779
780
781
782 list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
783
784 if (verbose(class)) {
785 graph_unlock();
786
787 printk("\nnew class %p: %s", class->key, class->name);
788 if (class->name_version > 1)
789 printk("#%d", class->name_version);
790 printk("\n");
791 dump_stack();
792
793 if (!graph_lock()) {
794 return NULL;
795 }
796 }
797out_unlock_set:
798 graph_unlock();
799
800out_set_class_cache:
801 if (!subclass || force)
802 lock->class_cache[0] = class;
803 else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
804 lock->class_cache[subclass] = class;
805
806
807
808
809
810 if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
811 return NULL;
812
813 return class;
814}
815
816#ifdef CONFIG_PROVE_LOCKING
817
818
819
820
821static struct lock_list *alloc_list_entry(void)
822{
823 if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
824 if (!debug_locks_off_graph_unlock())
825 return NULL;
826
827 print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
828 dump_stack();
829 return NULL;
830 }
831 return list_entries + nr_list_entries++;
832}
833
834
835
836
837static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
838 struct list_head *head, unsigned long ip,
839 int distance, struct stack_trace *trace)
840{
841 struct lock_list *entry;
842
843
844
845
846 entry = alloc_list_entry();
847 if (!entry)
848 return 0;
849
850 entry->class = this;
851 entry->distance = distance;
852 entry->trace = *trace;
853
854
855
856
857
858 list_add_tail_rcu(&entry->entry, head);
859
860 return 1;
861}
862
863
864
865
866#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
867#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
868
869
870
871
872
873
874
875struct circular_queue {
876 unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
877 unsigned int front, rear;
878};
879
880static struct circular_queue lock_cq;
881
882unsigned int max_bfs_queue_depth;
883
884static unsigned int lockdep_dependency_gen_id;
885
886static inline void __cq_init(struct circular_queue *cq)
887{
888 cq->front = cq->rear = 0;
889 lockdep_dependency_gen_id++;
890}
891
892static inline int __cq_empty(struct circular_queue *cq)
893{
894 return (cq->front == cq->rear);
895}
896
897static inline int __cq_full(struct circular_queue *cq)
898{
899 return ((cq->rear + 1) & CQ_MASK) == cq->front;
900}
901
902static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
903{
904 if (__cq_full(cq))
905 return -1;
906
907 cq->element[cq->rear] = elem;
908 cq->rear = (cq->rear + 1) & CQ_MASK;
909 return 0;
910}
911
912static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
913{
914 if (__cq_empty(cq))
915 return -1;
916
917 *elem = cq->element[cq->front];
918 cq->front = (cq->front + 1) & CQ_MASK;
919 return 0;
920}
921
922static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
923{
924 return (cq->rear - cq->front) & CQ_MASK;
925}
926
927static inline void mark_lock_accessed(struct lock_list *lock,
928 struct lock_list *parent)
929{
930 unsigned long nr;
931
932 nr = lock - list_entries;
933 WARN_ON(nr >= nr_list_entries);
934 lock->parent = parent;
935 lock->class->dep_gen_id = lockdep_dependency_gen_id;
936}
937
938static inline unsigned long lock_accessed(struct lock_list *lock)
939{
940 unsigned long nr;
941
942 nr = lock - list_entries;
943 WARN_ON(nr >= nr_list_entries);
944 return lock->class->dep_gen_id == lockdep_dependency_gen_id;
945}
946
947static inline struct lock_list *get_lock_parent(struct lock_list *child)
948{
949 return child->parent;
950}
951
952static inline int get_lock_depth(struct lock_list *child)
953{
954 int depth = 0;
955 struct lock_list *parent;
956
957 while ((parent = get_lock_parent(child))) {
958 child = parent;
959 depth++;
960 }
961 return depth;
962}
963
964static int __bfs(struct lock_list *source_entry,
965 void *data,
966 int (*match)(struct lock_list *entry, void *data),
967 struct lock_list **target_entry,
968 int forward)
969{
970 struct lock_list *entry;
971 struct list_head *head;
972 struct circular_queue *cq = &lock_cq;
973 int ret = 1;
974
975 if (match(source_entry, data)) {
976 *target_entry = source_entry;
977 ret = 0;
978 goto exit;
979 }
980
981 if (forward)
982 head = &source_entry->class->locks_after;
983 else
984 head = &source_entry->class->locks_before;
985
986 if (list_empty(head))
987 goto exit;
988
989 __cq_init(cq);
990 __cq_enqueue(cq, (unsigned long)source_entry);
991
992 while (!__cq_empty(cq)) {
993 struct lock_list *lock;
994
995 __cq_dequeue(cq, (unsigned long *)&lock);
996
997 if (!lock->class) {
998 ret = -2;
999 goto exit;
1000 }
1001
1002 if (forward)
1003 head = &lock->class->locks_after;
1004 else
1005 head = &lock->class->locks_before;
1006
1007 DEBUG_LOCKS_WARN_ON(!irqs_disabled());
1008
1009 list_for_each_entry_rcu(entry, head, entry) {
1010 if (!lock_accessed(entry)) {
1011 unsigned int cq_depth;
1012 mark_lock_accessed(entry, lock);
1013 if (match(entry, data)) {
1014 *target_entry = entry;
1015 ret = 0;
1016 goto exit;
1017 }
1018
1019 if (__cq_enqueue(cq, (unsigned long)entry)) {
1020 ret = -1;
1021 goto exit;
1022 }
1023 cq_depth = __cq_get_elem_count(cq);
1024 if (max_bfs_queue_depth < cq_depth)
1025 max_bfs_queue_depth = cq_depth;
1026 }
1027 }
1028 }
1029exit:
1030 return ret;
1031}
1032
1033static inline int __bfs_forwards(struct lock_list *src_entry,
1034 void *data,
1035 int (*match)(struct lock_list *entry, void *data),
1036 struct lock_list **target_entry)
1037{
1038 return __bfs(src_entry, data, match, target_entry, 1);
1039
1040}
1041
1042static inline int __bfs_backwards(struct lock_list *src_entry,
1043 void *data,
1044 int (*match)(struct lock_list *entry, void *data),
1045 struct lock_list **target_entry)
1046{
1047 return __bfs(src_entry, data, match, target_entry, 0);
1048
1049}
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061static noinline int
1062print_circular_bug_entry(struct lock_list *target, int depth)
1063{
1064 if (debug_locks_silent)
1065 return 0;
1066 printk("\n-> #%u", depth);
1067 print_lock_name(target->class);
1068 printk(":\n");
1069 print_stack_trace(&target->trace, 6);
1070
1071 return 0;
1072}
1073
1074static void
1075print_circular_lock_scenario(struct held_lock *src,
1076 struct held_lock *tgt,
1077 struct lock_list *prt)
1078{
1079 struct lock_class *source = hlock_class(src);
1080 struct lock_class *target = hlock_class(tgt);
1081 struct lock_class *parent = prt->class;
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096 if (parent != source) {
1097 printk("Chain exists of:\n ");
1098 __print_lock_name(source);
1099 printk(" --> ");
1100 __print_lock_name(parent);
1101 printk(" --> ");
1102 __print_lock_name(target);
1103 printk("\n\n");
1104 }
1105
1106 printk(" Possible unsafe locking scenario:\n\n");
1107 printk(" CPU0 CPU1\n");
1108 printk(" ---- ----\n");
1109 printk(" lock(");
1110 __print_lock_name(target);
1111 printk(");\n");
1112 printk(" lock(");
1113 __print_lock_name(parent);
1114 printk(");\n");
1115 printk(" lock(");
1116 __print_lock_name(target);
1117 printk(");\n");
1118 printk(" lock(");
1119 __print_lock_name(source);
1120 printk(");\n");
1121 printk("\n *** DEADLOCK ***\n\n");
1122}
1123
1124
1125
1126
1127
1128static noinline int
1129print_circular_bug_header(struct lock_list *entry, unsigned int depth,
1130 struct held_lock *check_src,
1131 struct held_lock *check_tgt)
1132{
1133 struct task_struct *curr = current;
1134
1135 if (debug_locks_silent)
1136 return 0;
1137
1138 printk("\n");
1139 printk("======================================================\n");
1140 printk("[ INFO: possible circular locking dependency detected ]\n");
1141 print_kernel_ident();
1142 printk("-------------------------------------------------------\n");
1143 printk("%s/%d is trying to acquire lock:\n",
1144 curr->comm, task_pid_nr(curr));
1145 print_lock(check_src);
1146 printk("\nbut task is already holding lock:\n");
1147 print_lock(check_tgt);
1148 printk("\nwhich lock already depends on the new lock.\n\n");
1149 printk("\nthe existing dependency chain (in reverse order) is:\n");
1150
1151 print_circular_bug_entry(entry, depth);
1152
1153 return 0;
1154}
1155
1156static inline int class_equal(struct lock_list *entry, void *data)
1157{
1158 return entry->class == data;
1159}
1160
1161static noinline int print_circular_bug(struct lock_list *this,
1162 struct lock_list *target,
1163 struct held_lock *check_src,
1164 struct held_lock *check_tgt)
1165{
1166 struct task_struct *curr = current;
1167 struct lock_list *parent;
1168 struct lock_list *first_parent;
1169 int depth;
1170
1171 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1172 return 0;
1173
1174 if (!save_trace(&this->trace))
1175 return 0;
1176
1177 depth = get_lock_depth(target);
1178
1179 print_circular_bug_header(target, depth, check_src, check_tgt);
1180
1181 parent = get_lock_parent(target);
1182 first_parent = parent;
1183
1184 while (parent) {
1185 print_circular_bug_entry(parent, --depth);
1186 parent = get_lock_parent(parent);
1187 }
1188
1189 printk("\nother info that might help us debug this:\n\n");
1190 print_circular_lock_scenario(check_src, check_tgt,
1191 first_parent);
1192
1193 lockdep_print_held_locks(curr);
1194
1195 printk("\nstack backtrace:\n");
1196 dump_stack();
1197
1198 return 0;
1199}
1200
1201static noinline int print_bfs_bug(int ret)
1202{
1203 if (!debug_locks_off_graph_unlock())
1204 return 0;
1205
1206
1207
1208
1209 WARN(1, "lockdep bfs error:%d\n", ret);
1210
1211 return 0;
1212}
1213
1214static int noop_count(struct lock_list *entry, void *data)
1215{
1216 (*(unsigned long *)data)++;
1217 return 0;
1218}
1219
1220static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
1221{
1222 unsigned long count = 0;
1223 struct lock_list *uninitialized_var(target_entry);
1224
1225 __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
1226
1227 return count;
1228}
1229unsigned long lockdep_count_forward_deps(struct lock_class *class)
1230{
1231 unsigned long ret, flags;
1232 struct lock_list this;
1233
1234 this.parent = NULL;
1235 this.class = class;
1236
1237 local_irq_save(flags);
1238 arch_spin_lock(&lockdep_lock);
1239 ret = __lockdep_count_forward_deps(&this);
1240 arch_spin_unlock(&lockdep_lock);
1241 local_irq_restore(flags);
1242
1243 return ret;
1244}
1245
1246static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
1247{
1248 unsigned long count = 0;
1249 struct lock_list *uninitialized_var(target_entry);
1250
1251 __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
1252
1253 return count;
1254}
1255
1256unsigned long lockdep_count_backward_deps(struct lock_class *class)
1257{
1258 unsigned long ret, flags;
1259 struct lock_list this;
1260
1261 this.parent = NULL;
1262 this.class = class;
1263
1264 local_irq_save(flags);
1265 arch_spin_lock(&lockdep_lock);
1266 ret = __lockdep_count_backward_deps(&this);
1267 arch_spin_unlock(&lockdep_lock);
1268 local_irq_restore(flags);
1269
1270 return ret;
1271}
1272
1273
1274
1275
1276
1277static noinline int
1278check_noncircular(struct lock_list *root, struct lock_class *target,
1279 struct lock_list **target_entry)
1280{
1281 int result;
1282
1283 debug_atomic_inc(nr_cyclic_checks);
1284
1285 result = __bfs_forwards(root, target, class_equal, target_entry);
1286
1287 return result;
1288}
1289
1290#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
1291
1292
1293
1294
1295
1296
1297static inline int usage_match(struct lock_list *entry, void *bit)
1298{
1299 return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
1300}
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314static int
1315find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
1316 struct lock_list **target_entry)
1317{
1318 int result;
1319
1320 debug_atomic_inc(nr_find_usage_forwards_checks);
1321
1322 result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
1323
1324 return result;
1325}
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337static int
1338find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
1339 struct lock_list **target_entry)
1340{
1341 int result;
1342
1343 debug_atomic_inc(nr_find_usage_backwards_checks);
1344
1345 result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
1346
1347 return result;
1348}
1349
1350static void print_lock_class_header(struct lock_class *class, int depth)
1351{
1352 int bit;
1353
1354 printk("%*s->", depth, "");
1355 print_lock_name(class);
1356 printk(" ops: %lu", class->ops);
1357 printk(" {\n");
1358
1359 for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
1360 if (class->usage_mask & (1 << bit)) {
1361 int len = depth;
1362
1363 len += printk("%*s %s", depth, "", usage_str[bit]);
1364 len += printk(" at:\n");
1365 print_stack_trace(class->usage_traces + bit, len);
1366 }
1367 }
1368 printk("%*s }\n", depth, "");
1369
1370 printk("%*s ... key at: ",depth,"");
1371 print_ip_sym((unsigned long)class->key);
1372}
1373
1374
1375
1376
1377static void __used
1378print_shortest_lock_dependencies(struct lock_list *leaf,
1379 struct lock_list *root)
1380{
1381 struct lock_list *entry = leaf;
1382 int depth;
1383
1384
1385 depth = get_lock_depth(leaf);
1386
1387 do {
1388 print_lock_class_header(entry->class, depth);
1389 printk("%*s ... acquired at:\n", depth, "");
1390 print_stack_trace(&entry->trace, 2);
1391 printk("\n");
1392
1393 if (depth == 0 && (entry != root)) {
1394 printk("lockdep:%s bad path found in chain graph\n", __func__);
1395 break;
1396 }
1397
1398 entry = get_lock_parent(entry);
1399 depth--;
1400 } while (entry && (depth >= 0));
1401
1402 return;
1403}
1404
1405static void
1406print_irq_lock_scenario(struct lock_list *safe_entry,
1407 struct lock_list *unsafe_entry,
1408 struct lock_class *prev_class,
1409 struct lock_class *next_class)
1410{
1411 struct lock_class *safe_class = safe_entry->class;
1412 struct lock_class *unsafe_class = unsafe_entry->class;
1413 struct lock_class *middle_class = prev_class;
1414
1415 if (middle_class == safe_class)
1416 middle_class = next_class;
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431 if (middle_class != unsafe_class) {
1432 printk("Chain exists of:\n ");
1433 __print_lock_name(safe_class);
1434 printk(" --> ");
1435 __print_lock_name(middle_class);
1436 printk(" --> ");
1437 __print_lock_name(unsafe_class);
1438 printk("\n\n");
1439 }
1440
1441 printk(" Possible interrupt unsafe locking scenario:\n\n");
1442 printk(" CPU0 CPU1\n");
1443 printk(" ---- ----\n");
1444 printk(" lock(");
1445 __print_lock_name(unsafe_class);
1446 printk(");\n");
1447 printk(" local_irq_disable();\n");
1448 printk(" lock(");
1449 __print_lock_name(safe_class);
1450 printk(");\n");
1451 printk(" lock(");
1452 __print_lock_name(middle_class);
1453 printk(");\n");
1454 printk(" <Interrupt>\n");
1455 printk(" lock(");
1456 __print_lock_name(safe_class);
1457 printk(");\n");
1458 printk("\n *** DEADLOCK ***\n\n");
1459}
1460
1461static int
1462print_bad_irq_dependency(struct task_struct *curr,
1463 struct lock_list *prev_root,
1464 struct lock_list *next_root,
1465 struct lock_list *backwards_entry,
1466 struct lock_list *forwards_entry,
1467 struct held_lock *prev,
1468 struct held_lock *next,
1469 enum lock_usage_bit bit1,
1470 enum lock_usage_bit bit2,
1471 const char *irqclass)
1472{
1473 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1474 return 0;
1475
1476 printk("\n");
1477 printk("======================================================\n");
1478 printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
1479 irqclass, irqclass);
1480 print_kernel_ident();
1481 printk("------------------------------------------------------\n");
1482 printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
1483 curr->comm, task_pid_nr(curr),
1484 curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
1485 curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
1486 curr->hardirqs_enabled,
1487 curr->softirqs_enabled);
1488 print_lock(next);
1489
1490 printk("\nand this task is already holding:\n");
1491 print_lock(prev);
1492 printk("which would create a new lock dependency:\n");
1493 print_lock_name(hlock_class(prev));
1494 printk(" ->");
1495 print_lock_name(hlock_class(next));
1496 printk("\n");
1497
1498 printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
1499 irqclass);
1500 print_lock_name(backwards_entry->class);
1501 printk("\n... which became %s-irq-safe at:\n", irqclass);
1502
1503 print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
1504
1505 printk("\nto a %s-irq-unsafe lock:\n", irqclass);
1506 print_lock_name(forwards_entry->class);
1507 printk("\n... which became %s-irq-unsafe at:\n", irqclass);
1508 printk("...");
1509
1510 print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
1511
1512 printk("\nother info that might help us debug this:\n\n");
1513 print_irq_lock_scenario(backwards_entry, forwards_entry,
1514 hlock_class(prev), hlock_class(next));
1515
1516 lockdep_print_held_locks(curr);
1517
1518 printk("\nthe dependencies between %s-irq-safe lock", irqclass);
1519 printk(" and the holding lock:\n");
1520 if (!save_trace(&prev_root->trace))
1521 return 0;
1522 print_shortest_lock_dependencies(backwards_entry, prev_root);
1523
1524 printk("\nthe dependencies between the lock to be acquired");
1525 printk(" and %s-irq-unsafe lock:\n", irqclass);
1526 if (!save_trace(&next_root->trace))
1527 return 0;
1528 print_shortest_lock_dependencies(forwards_entry, next_root);
1529
1530 printk("\nstack backtrace:\n");
1531 dump_stack();
1532
1533 return 0;
1534}
1535
1536static int
1537check_usage(struct task_struct *curr, struct held_lock *prev,
1538 struct held_lock *next, enum lock_usage_bit bit_backwards,
1539 enum lock_usage_bit bit_forwards, const char *irqclass)
1540{
1541 int ret;
1542 struct lock_list this, that;
1543 struct lock_list *uninitialized_var(target_entry);
1544 struct lock_list *uninitialized_var(target_entry1);
1545
1546 this.parent = NULL;
1547
1548 this.class = hlock_class(prev);
1549 ret = find_usage_backwards(&this, bit_backwards, &target_entry);
1550 if (ret < 0)
1551 return print_bfs_bug(ret);
1552 if (ret == 1)
1553 return ret;
1554
1555 that.parent = NULL;
1556 that.class = hlock_class(next);
1557 ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
1558 if (ret < 0)
1559 return print_bfs_bug(ret);
1560 if (ret == 1)
1561 return ret;
1562
1563 return print_bad_irq_dependency(curr, &this, &that,
1564 target_entry, target_entry1,
1565 prev, next,
1566 bit_backwards, bit_forwards, irqclass);
1567}
1568
1569static const char *state_names[] = {
1570#define LOCKDEP_STATE(__STATE) \
1571 __stringify(__STATE),
1572#include "lockdep_states.h"
1573#undef LOCKDEP_STATE
1574};
1575
1576static const char *state_rnames[] = {
1577#define LOCKDEP_STATE(__STATE) \
1578 __stringify(__STATE)"-READ",
1579#include "lockdep_states.h"
1580#undef LOCKDEP_STATE
1581};
1582
1583static inline const char *state_name(enum lock_usage_bit bit)
1584{
1585 return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
1586}
1587
1588static int exclusive_bit(int new_bit)
1589{
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601 int state = new_bit & ~3;
1602 int dir = new_bit & 2;
1603
1604
1605
1606
1607 return state | (dir ^ 2);
1608}
1609
1610static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
1611 struct held_lock *next, enum lock_usage_bit bit)
1612{
1613
1614
1615
1616
1617
1618
1619 if (!check_usage(curr, prev, next, bit,
1620 exclusive_bit(bit), state_name(bit)))
1621 return 0;
1622
1623 bit++;
1624
1625
1626
1627
1628
1629
1630
1631 if (!check_usage(curr, prev, next, bit,
1632 exclusive_bit(bit), state_name(bit)))
1633 return 0;
1634
1635 return 1;
1636}
1637
1638static int
1639check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1640 struct held_lock *next)
1641{
1642#define LOCKDEP_STATE(__STATE) \
1643 if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
1644 return 0;
1645#include "lockdep_states.h"
1646#undef LOCKDEP_STATE
1647
1648 return 1;
1649}
1650
1651static void inc_chains(void)
1652{
1653 if (current->hardirq_context)
1654 nr_hardirq_chains++;
1655 else {
1656 if (current->softirq_context)
1657 nr_softirq_chains++;
1658 else
1659 nr_process_chains++;
1660 }
1661}
1662
1663#else
1664
1665static inline int
1666check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1667 struct held_lock *next)
1668{
1669 return 1;
1670}
1671
1672static inline void inc_chains(void)
1673{
1674 nr_process_chains++;
1675}
1676
1677#endif
1678
1679static void
1680print_deadlock_scenario(struct held_lock *nxt,
1681 struct held_lock *prv)
1682{
1683 struct lock_class *next = hlock_class(nxt);
1684 struct lock_class *prev = hlock_class(prv);
1685
1686 printk(" Possible unsafe locking scenario:\n\n");
1687 printk(" CPU0\n");
1688 printk(" ----\n");
1689 printk(" lock(");
1690 __print_lock_name(prev);
1691 printk(");\n");
1692 printk(" lock(");
1693 __print_lock_name(next);
1694 printk(");\n");
1695 printk("\n *** DEADLOCK ***\n\n");
1696 printk(" May be due to missing lock nesting notation\n\n");
1697}
1698
1699static int
1700print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
1701 struct held_lock *next)
1702{
1703 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1704 return 0;
1705
1706 printk("\n");
1707 printk("=============================================\n");
1708 printk("[ INFO: possible recursive locking detected ]\n");
1709 print_kernel_ident();
1710 printk("---------------------------------------------\n");
1711 printk("%s/%d is trying to acquire lock:\n",
1712 curr->comm, task_pid_nr(curr));
1713 print_lock(next);
1714 printk("\nbut task is already holding lock:\n");
1715 print_lock(prev);
1716
1717 printk("\nother info that might help us debug this:\n");
1718 print_deadlock_scenario(next, prev);
1719 lockdep_print_held_locks(curr);
1720
1721 printk("\nstack backtrace:\n");
1722 dump_stack();
1723
1724 return 0;
1725}
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735static int
1736check_deadlock(struct task_struct *curr, struct held_lock *next,
1737 struct lockdep_map *next_instance, int read)
1738{
1739 struct held_lock *prev;
1740 struct held_lock *nest = NULL;
1741 int i;
1742
1743 for (i = 0; i < curr->lockdep_depth; i++) {
1744 prev = curr->held_locks + i;
1745
1746 if (prev->instance == next->nest_lock)
1747 nest = prev;
1748
1749 if (hlock_class(prev) != hlock_class(next))
1750 continue;
1751
1752
1753
1754
1755
1756 if ((read == 2) && prev->read)
1757 return 2;
1758
1759
1760
1761
1762
1763 if (nest)
1764 return 2;
1765
1766 return print_deadlock_bug(curr, prev, next);
1767 }
1768 return 1;
1769}
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793static int
1794check_prev_add(struct task_struct *curr, struct held_lock *prev,
1795 struct held_lock *next, int distance, int *stack_saved)
1796{
1797 struct lock_list *entry;
1798 int ret;
1799 struct lock_list this;
1800 struct lock_list *uninitialized_var(target_entry);
1801
1802
1803
1804
1805
1806
1807
1808 static struct stack_trace trace;
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819 this.class = hlock_class(next);
1820 this.parent = NULL;
1821 ret = check_noncircular(&this, hlock_class(prev), &target_entry);
1822 if (unlikely(!ret))
1823 return print_circular_bug(&this, target_entry, next, prev);
1824 else if (unlikely(ret < 0))
1825 return print_bfs_bug(ret);
1826
1827 if (!check_prev_add_irq(curr, prev, next))
1828 return 0;
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838 if (next->read == 2 || prev->read == 2)
1839 return 1;
1840
1841
1842
1843
1844
1845
1846
1847
1848 list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
1849 if (entry->class == hlock_class(next)) {
1850 if (distance == 1)
1851 entry->distance = 1;
1852 return 2;
1853 }
1854 }
1855
1856 if (!*stack_saved) {
1857 if (!save_trace(&trace))
1858 return 0;
1859 *stack_saved = 1;
1860 }
1861
1862
1863
1864
1865
1866 ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
1867 &hlock_class(prev)->locks_after,
1868 next->acquire_ip, distance, &trace);
1869
1870 if (!ret)
1871 return 0;
1872
1873 ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
1874 &hlock_class(next)->locks_before,
1875 next->acquire_ip, distance, &trace);
1876 if (!ret)
1877 return 0;
1878
1879
1880
1881
1882 if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
1883
1884 *stack_saved = 0;
1885 graph_unlock();
1886 printk("\n new dependency: ");
1887 print_lock_name(hlock_class(prev));
1888 printk(" => ");
1889 print_lock_name(hlock_class(next));
1890 printk("\n");
1891 dump_stack();
1892 return graph_lock();
1893 }
1894 return 1;
1895}
1896
1897
1898
1899
1900
1901
1902
1903static int
1904check_prevs_add(struct task_struct *curr, struct held_lock *next)
1905{
1906 int depth = curr->lockdep_depth;
1907 int stack_saved = 0;
1908 struct held_lock *hlock;
1909
1910
1911
1912
1913
1914
1915 if (!depth)
1916 goto out_bug;
1917
1918
1919
1920
1921 if (curr->held_locks[depth].irq_context !=
1922 curr->held_locks[depth-1].irq_context)
1923 goto out_bug;
1924
1925 for (;;) {
1926 int distance = curr->lockdep_depth - depth + 1;
1927 hlock = curr->held_locks + depth - 1;
1928
1929
1930
1931
1932 if (hlock->read != 2 && hlock->check) {
1933 if (!check_prev_add(curr, hlock, next,
1934 distance, &stack_saved))
1935 return 0;
1936
1937
1938
1939
1940
1941
1942 if (!hlock->trylock)
1943 break;
1944 }
1945 depth--;
1946
1947
1948
1949 if (!depth)
1950 break;
1951
1952
1953
1954 if (curr->held_locks[depth].irq_context !=
1955 curr->held_locks[depth-1].irq_context)
1956 break;
1957 }
1958 return 1;
1959out_bug:
1960 if (!debug_locks_off_graph_unlock())
1961 return 0;
1962
1963
1964
1965
1966
1967
1968 WARN_ON(1);
1969
1970 return 0;
1971}
1972
1973unsigned long nr_lock_chains;
1974struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
1975int nr_chain_hlocks;
1976static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
1977
1978struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
1979{
1980 return lock_classes + chain_hlocks[chain->base + i];
1981}
1982
1983
1984
1985
1986static inline int get_first_held_lock(struct task_struct *curr,
1987 struct held_lock *hlock)
1988{
1989 int i;
1990 struct held_lock *hlock_curr;
1991
1992 for (i = curr->lockdep_depth - 1; i >= 0; i--) {
1993 hlock_curr = curr->held_locks + i;
1994 if (hlock_curr->irq_context != hlock->irq_context)
1995 break;
1996
1997 }
1998
1999 return ++i;
2000}
2001
2002#ifdef CONFIG_DEBUG_LOCKDEP
2003
2004
2005
2006static u64 print_chain_key_iteration(int class_idx, u64 chain_key)
2007{
2008 u64 new_chain_key = iterate_chain_key(chain_key, class_idx);
2009
2010 printk(" class_idx:%d -> chain_key:%016Lx",
2011 class_idx,
2012 (unsigned long long)new_chain_key);
2013 return new_chain_key;
2014}
2015
2016static void
2017print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
2018{
2019 struct held_lock *hlock;
2020 u64 chain_key = 0;
2021 int depth = curr->lockdep_depth;
2022 int i;
2023
2024 printk("depth: %u\n", depth + 1);
2025 for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) {
2026 hlock = curr->held_locks + i;
2027 chain_key = print_chain_key_iteration(hlock->class_idx, chain_key);
2028
2029 print_lock(hlock);
2030 }
2031
2032 print_chain_key_iteration(hlock_next->class_idx, chain_key);
2033 print_lock(hlock_next);
2034}
2035
2036static void print_chain_keys_chain(struct lock_chain *chain)
2037{
2038 int i;
2039 u64 chain_key = 0;
2040 int class_id;
2041
2042 printk("depth: %u\n", chain->depth);
2043 for (i = 0; i < chain->depth; i++) {
2044 class_id = chain_hlocks[chain->base + i];
2045 chain_key = print_chain_key_iteration(class_id + 1, chain_key);
2046
2047 print_lock_name(lock_classes + class_id);
2048 printk("\n");
2049 }
2050}
2051
2052static void print_collision(struct task_struct *curr,
2053 struct held_lock *hlock_next,
2054 struct lock_chain *chain)
2055{
2056 printk("\n");
2057 printk("======================\n");
2058 printk("[chain_key collision ]\n");
2059 print_kernel_ident();
2060 printk("----------------------\n");
2061 printk("%s/%d: ", current->comm, task_pid_nr(current));
2062 printk("Hash chain already cached but the contents don't match!\n");
2063
2064 printk("Held locks:");
2065 print_chain_keys_held_locks(curr, hlock_next);
2066
2067 printk("Locks in cached chain:");
2068 print_chain_keys_chain(chain);
2069
2070 printk("\nstack backtrace:\n");
2071 dump_stack();
2072}
2073#endif
2074
2075
2076
2077
2078
2079
2080
2081static int check_no_collision(struct task_struct *curr,
2082 struct held_lock *hlock,
2083 struct lock_chain *chain)
2084{
2085#ifdef CONFIG_DEBUG_LOCKDEP
2086 int i, j, id;
2087
2088 i = get_first_held_lock(curr, hlock);
2089
2090 if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) {
2091 print_collision(curr, hlock, chain);
2092 return 0;
2093 }
2094
2095 for (j = 0; j < chain->depth - 1; j++, i++) {
2096 id = curr->held_locks[i].class_idx - 1;
2097
2098 if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {
2099 print_collision(curr, hlock, chain);
2100 return 0;
2101 }
2102 }
2103#endif
2104 return 1;
2105}
2106
2107
2108
2109
2110
2111
2112
2113static inline int lookup_chain_cache(struct task_struct *curr,
2114 struct held_lock *hlock,
2115 u64 chain_key)
2116{
2117 struct lock_class *class = hlock_class(hlock);
2118 struct hlist_head *hash_head = chainhashentry(chain_key);
2119 struct lock_chain *chain;
2120 int i, j;
2121
2122
2123
2124
2125
2126
2127 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2128 return 0;
2129
2130
2131
2132
2133 hlist_for_each_entry_rcu(chain, hash_head, entry) {
2134 if (chain->chain_key == chain_key) {
2135cache_hit:
2136 debug_atomic_inc(chain_lookup_hits);
2137 if (!check_no_collision(curr, hlock, chain))
2138 return 0;
2139
2140 if (very_verbose(class))
2141 printk("\nhash chain already cached, key: "
2142 "%016Lx tail class: [%p] %s\n",
2143 (unsigned long long)chain_key,
2144 class->key, class->name);
2145 return 0;
2146 }
2147 }
2148 if (very_verbose(class))
2149 printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
2150 (unsigned long long)chain_key, class->key, class->name);
2151
2152
2153
2154
2155 if (!graph_lock())
2156 return 0;
2157
2158
2159
2160 hlist_for_each_entry(chain, hash_head, entry) {
2161 if (chain->chain_key == chain_key) {
2162 graph_unlock();
2163 goto cache_hit;
2164 }
2165 }
2166 if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
2167 if (!debug_locks_off_graph_unlock())
2168 return 0;
2169
2170 print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
2171 dump_stack();
2172 return 0;
2173 }
2174 chain = lock_chains + nr_lock_chains++;
2175 chain->chain_key = chain_key;
2176 chain->irq_context = hlock->irq_context;
2177 i = get_first_held_lock(curr, hlock);
2178 chain->depth = curr->lockdep_depth + 1 - i;
2179
2180 BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks));
2181 BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks));
2182 BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes));
2183
2184 if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
2185 chain->base = nr_chain_hlocks;
2186 for (j = 0; j < chain->depth - 1; j++, i++) {
2187 int lock_id = curr->held_locks[i].class_idx - 1;
2188 chain_hlocks[chain->base + j] = lock_id;
2189 }
2190 chain_hlocks[chain->base + j] = class - lock_classes;
2191 }
2192
2193 if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS)
2194 nr_chain_hlocks += chain->depth;
2195
2196#ifdef CONFIG_DEBUG_LOCKDEP
2197
2198
2199
2200 if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) {
2201 if (debug_locks_off_graph_unlock())
2202 return 0;
2203
2204 print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
2205 dump_stack();
2206 return 0;
2207 }
2208#endif
2209
2210 hlist_add_head_rcu(&chain->entry, hash_head);
2211 debug_atomic_inc(chain_lookup_misses);
2212 inc_chains();
2213
2214 return 1;
2215}
2216
2217static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
2218 struct held_lock *hlock, int chain_head, u64 chain_key)
2219{
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230 if (!hlock->trylock && hlock->check &&
2231 lookup_chain_cache(curr, hlock, chain_key)) {
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244 int ret = check_deadlock(curr, hlock, lock, hlock->read);
2245
2246 if (!ret)
2247 return 0;
2248
2249
2250
2251
2252
2253 if (ret == 2)
2254 hlock->read = 2;
2255
2256
2257
2258
2259 if (!chain_head && ret != 2)
2260 if (!check_prevs_add(curr, hlock))
2261 return 0;
2262 graph_unlock();
2263 } else
2264
2265 if (unlikely(!debug_locks))
2266 return 0;
2267
2268 return 1;
2269}
2270#else
2271static inline int validate_chain(struct task_struct *curr,
2272 struct lockdep_map *lock, struct held_lock *hlock,
2273 int chain_head, u64 chain_key)
2274{
2275 return 1;
2276}
2277#endif
2278
2279
2280
2281
2282
2283static void check_chain_key(struct task_struct *curr)
2284{
2285#ifdef CONFIG_DEBUG_LOCKDEP
2286 struct held_lock *hlock, *prev_hlock = NULL;
2287 unsigned int i;
2288 u64 chain_key = 0;
2289
2290 for (i = 0; i < curr->lockdep_depth; i++) {
2291 hlock = curr->held_locks + i;
2292 if (chain_key != hlock->prev_chain_key) {
2293 debug_locks_off();
2294
2295
2296
2297
2298 WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
2299 curr->lockdep_depth, i,
2300 (unsigned long long)chain_key,
2301 (unsigned long long)hlock->prev_chain_key);
2302 return;
2303 }
2304
2305
2306
2307 if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS))
2308 return;
2309
2310 if (prev_hlock && (prev_hlock->irq_context !=
2311 hlock->irq_context))
2312 chain_key = 0;
2313 chain_key = iterate_chain_key(chain_key, hlock->class_idx);
2314 prev_hlock = hlock;
2315 }
2316 if (chain_key != curr->curr_chain_key) {
2317 debug_locks_off();
2318
2319
2320
2321
2322 WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
2323 curr->lockdep_depth, i,
2324 (unsigned long long)chain_key,
2325 (unsigned long long)curr->curr_chain_key);
2326 }
2327#endif
2328}
2329
2330static void
2331print_usage_bug_scenario(struct held_lock *lock)
2332{
2333 struct lock_class *class = hlock_class(lock);
2334
2335 printk(" Possible unsafe locking scenario:\n\n");
2336 printk(" CPU0\n");
2337 printk(" ----\n");
2338 printk(" lock(");
2339 __print_lock_name(class);
2340 printk(");\n");
2341 printk(" <Interrupt>\n");
2342 printk(" lock(");
2343 __print_lock_name(class);
2344 printk(");\n");
2345 printk("\n *** DEADLOCK ***\n\n");
2346}
2347
2348static int
2349print_usage_bug(struct task_struct *curr, struct held_lock *this,
2350 enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
2351{
2352 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2353 return 0;
2354
2355 printk("\n");
2356 printk("=================================\n");
2357 printk("[ INFO: inconsistent lock state ]\n");
2358 print_kernel_ident();
2359 printk("---------------------------------\n");
2360
2361 printk("inconsistent {%s} -> {%s} usage.\n",
2362 usage_str[prev_bit], usage_str[new_bit]);
2363
2364 printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
2365 curr->comm, task_pid_nr(curr),
2366 trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
2367 trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
2368 trace_hardirqs_enabled(curr),
2369 trace_softirqs_enabled(curr));
2370 print_lock(this);
2371
2372 printk("{%s} state was registered at:\n", usage_str[prev_bit]);
2373 print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
2374
2375 print_irqtrace_events(curr);
2376 printk("\nother info that might help us debug this:\n");
2377 print_usage_bug_scenario(this);
2378
2379 lockdep_print_held_locks(curr);
2380
2381 printk("\nstack backtrace:\n");
2382 dump_stack();
2383
2384 return 0;
2385}
2386
2387
2388
2389
2390static inline int
2391valid_state(struct task_struct *curr, struct held_lock *this,
2392 enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
2393{
2394 if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
2395 return print_usage_bug(curr, this, bad_bit, new_bit);
2396 return 1;
2397}
2398
2399static int mark_lock(struct task_struct *curr, struct held_lock *this,
2400 enum lock_usage_bit new_bit);
2401
2402#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
2403
2404
2405
2406
2407static int
2408print_irq_inversion_bug(struct task_struct *curr,
2409 struct lock_list *root, struct lock_list *other,
2410 struct held_lock *this, int forwards,
2411 const char *irqclass)
2412{
2413 struct lock_list *entry = other;
2414 struct lock_list *middle = NULL;
2415 int depth;
2416
2417 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2418 return 0;
2419
2420 printk("\n");
2421 printk("=========================================================\n");
2422 printk("[ INFO: possible irq lock inversion dependency detected ]\n");
2423 print_kernel_ident();
2424 printk("---------------------------------------------------------\n");
2425 printk("%s/%d just changed the state of lock:\n",
2426 curr->comm, task_pid_nr(curr));
2427 print_lock(this);
2428 if (forwards)
2429 printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
2430 else
2431 printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
2432 print_lock_name(other->class);
2433 printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
2434
2435 printk("\nother info that might help us debug this:\n");
2436
2437
2438 depth = get_lock_depth(other);
2439 do {
2440 if (depth == 0 && (entry != root)) {
2441 printk("lockdep:%s bad path found in chain graph\n", __func__);
2442 break;
2443 }
2444 middle = entry;
2445 entry = get_lock_parent(entry);
2446 depth--;
2447 } while (entry && entry != root && (depth >= 0));
2448 if (forwards)
2449 print_irq_lock_scenario(root, other,
2450 middle ? middle->class : root->class, other->class);
2451 else
2452 print_irq_lock_scenario(other, root,
2453 middle ? middle->class : other->class, root->class);
2454
2455 lockdep_print_held_locks(curr);
2456
2457 printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
2458 if (!save_trace(&root->trace))
2459 return 0;
2460 print_shortest_lock_dependencies(other, root);
2461
2462 printk("\nstack backtrace:\n");
2463 dump_stack();
2464
2465 return 0;
2466}
2467
2468
2469
2470
2471
2472static int
2473check_usage_forwards(struct task_struct *curr, struct held_lock *this,
2474 enum lock_usage_bit bit, const char *irqclass)
2475{
2476 int ret;
2477 struct lock_list root;
2478 struct lock_list *uninitialized_var(target_entry);
2479
2480 root.parent = NULL;
2481 root.class = hlock_class(this);
2482 ret = find_usage_forwards(&root, bit, &target_entry);
2483 if (ret < 0)
2484 return print_bfs_bug(ret);
2485 if (ret == 1)
2486 return ret;
2487
2488 return print_irq_inversion_bug(curr, &root, target_entry,
2489 this, 1, irqclass);
2490}
2491
2492
2493
2494
2495
2496static int
2497check_usage_backwards(struct task_struct *curr, struct held_lock *this,
2498 enum lock_usage_bit bit, const char *irqclass)
2499{
2500 int ret;
2501 struct lock_list root;
2502 struct lock_list *uninitialized_var(target_entry);
2503
2504 root.parent = NULL;
2505 root.class = hlock_class(this);
2506 ret = find_usage_backwards(&root, bit, &target_entry);
2507 if (ret < 0)
2508 return print_bfs_bug(ret);
2509 if (ret == 1)
2510 return ret;
2511
2512 return print_irq_inversion_bug(curr, &root, target_entry,
2513 this, 0, irqclass);
2514}
2515
2516void print_irqtrace_events(struct task_struct *curr)
2517{
2518 printk("irq event stamp: %u\n", curr->irq_events);
2519 printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
2520 print_ip_sym(curr->hardirq_enable_ip);
2521 printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
2522 print_ip_sym(curr->hardirq_disable_ip);
2523 printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
2524 print_ip_sym(curr->softirq_enable_ip);
2525 printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
2526 print_ip_sym(curr->softirq_disable_ip);
2527}
2528
2529static int HARDIRQ_verbose(struct lock_class *class)
2530{
2531#if HARDIRQ_VERBOSE
2532 return class_filter(class);
2533#endif
2534 return 0;
2535}
2536
2537static int SOFTIRQ_verbose(struct lock_class *class)
2538{
2539#if SOFTIRQ_VERBOSE
2540 return class_filter(class);
2541#endif
2542 return 0;
2543}
2544
2545static int RECLAIM_FS_verbose(struct lock_class *class)
2546{
2547#if RECLAIM_VERBOSE
2548 return class_filter(class);
2549#endif
2550 return 0;
2551}
2552
2553#define STRICT_READ_CHECKS 1
2554
2555static int (*state_verbose_f[])(struct lock_class *class) = {
2556#define LOCKDEP_STATE(__STATE) \
2557 __STATE##_verbose,
2558#include "lockdep_states.h"
2559#undef LOCKDEP_STATE
2560};
2561
2562static inline int state_verbose(enum lock_usage_bit bit,
2563 struct lock_class *class)
2564{
2565 return state_verbose_f[bit >> 2](class);
2566}
2567
2568typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
2569 enum lock_usage_bit bit, const char *name);
2570
2571static int
2572mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2573 enum lock_usage_bit new_bit)
2574{
2575 int excl_bit = exclusive_bit(new_bit);
2576 int read = new_bit & 1;
2577 int dir = new_bit & 2;
2578
2579
2580
2581
2582
2583
2584
2585
2586 check_usage_f usage = dir ?
2587 check_usage_backwards : check_usage_forwards;
2588
2589
2590
2591
2592
2593 if (!valid_state(curr, this, new_bit, excl_bit))
2594 return 0;
2595
2596
2597
2598
2599
2600 if ((!read || !dir || STRICT_READ_CHECKS) &&
2601 !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
2602 return 0;
2603
2604
2605
2606
2607 if (!read) {
2608 if (!valid_state(curr, this, new_bit, excl_bit + 1))
2609 return 0;
2610
2611 if (STRICT_READ_CHECKS &&
2612 !usage(curr, this, excl_bit + 1,
2613 state_name(new_bit + 1)))
2614 return 0;
2615 }
2616
2617 if (state_verbose(new_bit, hlock_class(this)))
2618 return 2;
2619
2620 return 1;
2621}
2622
2623enum mark_type {
2624#define LOCKDEP_STATE(__STATE) __STATE,
2625#include "lockdep_states.h"
2626#undef LOCKDEP_STATE
2627};
2628
2629
2630
2631
2632static int
2633mark_held_locks(struct task_struct *curr, enum mark_type mark)
2634{
2635 enum lock_usage_bit usage_bit;
2636 struct held_lock *hlock;
2637 int i;
2638
2639 for (i = 0; i < curr->lockdep_depth; i++) {
2640 hlock = curr->held_locks + i;
2641
2642 usage_bit = 2 + (mark << 2);
2643 if (hlock->read)
2644 usage_bit += 1;
2645
2646 BUG_ON(usage_bit >= LOCK_USAGE_STATES);
2647
2648 if (!hlock->check)
2649 continue;
2650
2651 if (!mark_lock(curr, hlock, usage_bit))
2652 return 0;
2653 }
2654
2655 return 1;
2656}
2657
2658
2659
2660
2661static void __trace_hardirqs_on_caller(unsigned long ip)
2662{
2663 struct task_struct *curr = current;
2664
2665
2666 curr->hardirqs_enabled = 1;
2667
2668
2669
2670
2671
2672 if (!mark_held_locks(curr, HARDIRQ))
2673 return;
2674
2675
2676
2677
2678
2679 if (curr->softirqs_enabled)
2680 if (!mark_held_locks(curr, SOFTIRQ))
2681 return;
2682
2683 curr->hardirq_enable_ip = ip;
2684 curr->hardirq_enable_event = ++curr->irq_events;
2685 debug_atomic_inc(hardirqs_on_events);
2686}
2687
2688__visible void trace_hardirqs_on_caller(unsigned long ip)
2689{
2690 time_hardirqs_on(CALLER_ADDR0, ip);
2691
2692 if (unlikely(!debug_locks || current->lockdep_recursion))
2693 return;
2694
2695 if (unlikely(current->hardirqs_enabled)) {
2696
2697
2698
2699
2700
2701 __debug_atomic_inc(redundant_hardirqs_on);
2702 return;
2703 }
2704
2705
2706
2707
2708
2709
2710 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2711 return;
2712
2713
2714
2715
2716 if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
2717 return;
2718
2719
2720
2721
2722
2723 if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
2724 return;
2725
2726 current->lockdep_recursion = 1;
2727 __trace_hardirqs_on_caller(ip);
2728 current->lockdep_recursion = 0;
2729}
2730EXPORT_SYMBOL(trace_hardirqs_on_caller);
2731
2732void trace_hardirqs_on(void)
2733{
2734 trace_hardirqs_on_caller(CALLER_ADDR0);
2735}
2736EXPORT_SYMBOL(trace_hardirqs_on);
2737
2738
2739
2740
2741__visible void trace_hardirqs_off_caller(unsigned long ip)
2742{
2743 struct task_struct *curr = current;
2744
2745 time_hardirqs_off(CALLER_ADDR0, ip);
2746
2747 if (unlikely(!debug_locks || current->lockdep_recursion))
2748 return;
2749
2750
2751
2752
2753
2754 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2755 return;
2756
2757 if (curr->hardirqs_enabled) {
2758
2759
2760
2761 curr->hardirqs_enabled = 0;
2762 curr->hardirq_disable_ip = ip;
2763 curr->hardirq_disable_event = ++curr->irq_events;
2764 debug_atomic_inc(hardirqs_off_events);
2765 } else
2766 debug_atomic_inc(redundant_hardirqs_off);
2767}
2768EXPORT_SYMBOL(trace_hardirqs_off_caller);
2769
2770void trace_hardirqs_off(void)
2771{
2772 trace_hardirqs_off_caller(CALLER_ADDR0);
2773}
2774EXPORT_SYMBOL(trace_hardirqs_off);
2775
2776
2777
2778
2779void trace_softirqs_on(unsigned long ip)
2780{
2781 struct task_struct *curr = current;
2782
2783 if (unlikely(!debug_locks || current->lockdep_recursion))
2784 return;
2785
2786
2787
2788
2789
2790 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2791 return;
2792
2793 if (curr->softirqs_enabled) {
2794 debug_atomic_inc(redundant_softirqs_on);
2795 return;
2796 }
2797
2798 current->lockdep_recursion = 1;
2799
2800
2801
2802 curr->softirqs_enabled = 1;
2803 curr->softirq_enable_ip = ip;
2804 curr->softirq_enable_event = ++curr->irq_events;
2805 debug_atomic_inc(softirqs_on_events);
2806
2807
2808
2809
2810
2811 if (curr->hardirqs_enabled)
2812 mark_held_locks(curr, SOFTIRQ);
2813 current->lockdep_recursion = 0;
2814}
2815
2816
2817
2818
2819void trace_softirqs_off(unsigned long ip)
2820{
2821 struct task_struct *curr = current;
2822
2823 if (unlikely(!debug_locks || current->lockdep_recursion))
2824 return;
2825
2826
2827
2828
2829 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2830 return;
2831
2832 if (curr->softirqs_enabled) {
2833
2834
2835
2836 curr->softirqs_enabled = 0;
2837 curr->softirq_disable_ip = ip;
2838 curr->softirq_disable_event = ++curr->irq_events;
2839 debug_atomic_inc(softirqs_off_events);
2840
2841
2842
2843 DEBUG_LOCKS_WARN_ON(!softirq_count());
2844 } else
2845 debug_atomic_inc(redundant_softirqs_off);
2846}
2847
2848static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
2849{
2850 struct task_struct *curr = current;
2851
2852 if (unlikely(!debug_locks))
2853 return;
2854
2855
2856 if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
2857 return;
2858
2859
2860 if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
2861 return;
2862
2863
2864 if (!(gfp_mask & __GFP_FS))
2865 return;
2866
2867
2868
2869
2870 if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
2871 return;
2872
2873 mark_held_locks(curr, RECLAIM_FS);
2874}
2875
2876static void check_flags(unsigned long flags);
2877
2878void lockdep_trace_alloc(gfp_t gfp_mask)
2879{
2880 unsigned long flags;
2881
2882 if (unlikely(current->lockdep_recursion))
2883 return;
2884
2885 raw_local_irq_save(flags);
2886 check_flags(flags);
2887 current->lockdep_recursion = 1;
2888 __lockdep_trace_alloc(gfp_mask, flags);
2889 current->lockdep_recursion = 0;
2890 raw_local_irq_restore(flags);
2891}
2892
2893static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
2894{
2895
2896
2897
2898
2899 if (!hlock->trylock) {
2900 if (hlock->read) {
2901 if (curr->hardirq_context)
2902 if (!mark_lock(curr, hlock,
2903 LOCK_USED_IN_HARDIRQ_READ))
2904 return 0;
2905 if (curr->softirq_context)
2906 if (!mark_lock(curr, hlock,
2907 LOCK_USED_IN_SOFTIRQ_READ))
2908 return 0;
2909 } else {
2910 if (curr->hardirq_context)
2911 if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
2912 return 0;
2913 if (curr->softirq_context)
2914 if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
2915 return 0;
2916 }
2917 }
2918 if (!hlock->hardirqs_off) {
2919 if (hlock->read) {
2920 if (!mark_lock(curr, hlock,
2921 LOCK_ENABLED_HARDIRQ_READ))
2922 return 0;
2923 if (curr->softirqs_enabled)
2924 if (!mark_lock(curr, hlock,
2925 LOCK_ENABLED_SOFTIRQ_READ))
2926 return 0;
2927 } else {
2928 if (!mark_lock(curr, hlock,
2929 LOCK_ENABLED_HARDIRQ))
2930 return 0;
2931 if (curr->softirqs_enabled)
2932 if (!mark_lock(curr, hlock,
2933 LOCK_ENABLED_SOFTIRQ))
2934 return 0;
2935 }
2936 }
2937
2938
2939
2940
2941
2942
2943
2944 if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
2945 if (hlock->read) {
2946 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
2947 return 0;
2948 } else {
2949 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
2950 return 0;
2951 }
2952 }
2953
2954 return 1;
2955}
2956
2957static inline unsigned int task_irq_context(struct task_struct *task)
2958{
2959 return 2 * !!task->hardirq_context + !!task->softirq_context;
2960}
2961
2962static int separate_irq_context(struct task_struct *curr,
2963 struct held_lock *hlock)
2964{
2965 unsigned int depth = curr->lockdep_depth;
2966
2967
2968
2969
2970 if (depth) {
2971 struct held_lock *prev_hlock;
2972
2973 prev_hlock = curr->held_locks + depth-1;
2974
2975
2976
2977
2978
2979 if (prev_hlock->irq_context != hlock->irq_context)
2980 return 1;
2981 }
2982 return 0;
2983}
2984
2985#else
2986
2987static inline
2988int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2989 enum lock_usage_bit new_bit)
2990{
2991 WARN_ON(1);
2992 return 1;
2993}
2994
2995static inline int mark_irqflags(struct task_struct *curr,
2996 struct held_lock *hlock)
2997{
2998 return 1;
2999}
3000
3001static inline unsigned int task_irq_context(struct task_struct *task)
3002{
3003 return 0;
3004}
3005
3006static inline int separate_irq_context(struct task_struct *curr,
3007 struct held_lock *hlock)
3008{
3009 return 0;
3010}
3011
3012void lockdep_trace_alloc(gfp_t gfp_mask)
3013{
3014}
3015
3016#endif
3017
3018
3019
3020
3021static int mark_lock(struct task_struct *curr, struct held_lock *this,
3022 enum lock_usage_bit new_bit)
3023{
3024 unsigned int new_mask = 1 << new_bit, ret = 1;
3025
3026
3027
3028
3029
3030 if (likely(hlock_class(this)->usage_mask & new_mask))
3031 return 1;
3032
3033 if (!graph_lock())
3034 return 0;
3035
3036
3037
3038 if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
3039 graph_unlock();
3040 return 1;
3041 }
3042
3043 hlock_class(this)->usage_mask |= new_mask;
3044
3045 if (!save_trace(hlock_class(this)->usage_traces + new_bit))
3046 return 0;
3047
3048 switch (new_bit) {
3049#define LOCKDEP_STATE(__STATE) \
3050 case LOCK_USED_IN_##__STATE: \
3051 case LOCK_USED_IN_##__STATE##_READ: \
3052 case LOCK_ENABLED_##__STATE: \
3053 case LOCK_ENABLED_##__STATE##_READ:
3054#include "lockdep_states.h"
3055#undef LOCKDEP_STATE
3056 ret = mark_lock_irq(curr, this, new_bit);
3057 if (!ret)
3058 return 0;
3059 break;
3060 case LOCK_USED:
3061 debug_atomic_dec(nr_unused_locks);
3062 break;
3063 default:
3064 if (!debug_locks_off_graph_unlock())
3065 return 0;
3066 WARN_ON(1);
3067 return 0;
3068 }
3069
3070 graph_unlock();
3071
3072
3073
3074
3075 if (ret == 2) {
3076 printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
3077 print_lock(this);
3078 print_irqtrace_events(curr);
3079 dump_stack();
3080 }
3081
3082 return ret;
3083}
3084
3085
3086
3087
3088void lockdep_init_map(struct lockdep_map *lock, const char *name,
3089 struct lock_class_key *key, int subclass)
3090{
3091 int i;
3092
3093 kmemcheck_mark_initialized(lock, sizeof(*lock));
3094
3095 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
3096 lock->class_cache[i] = NULL;
3097
3098#ifdef CONFIG_LOCK_STAT
3099 lock->cpu = raw_smp_processor_id();
3100#endif
3101
3102
3103
3104
3105 if (DEBUG_LOCKS_WARN_ON(!name)) {
3106 lock->name = "NULL";
3107 return;
3108 }
3109
3110 lock->name = name;
3111
3112
3113
3114
3115 if (DEBUG_LOCKS_WARN_ON(!key))
3116 return;
3117
3118
3119
3120 if (!static_obj(key)) {
3121 printk("BUG: key %p not in .data!\n", key);
3122
3123
3124
3125 DEBUG_LOCKS_WARN_ON(1);
3126 return;
3127 }
3128 lock->key = key;
3129
3130 if (unlikely(!debug_locks))
3131 return;
3132
3133 if (subclass) {
3134 unsigned long flags;
3135
3136 if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion))
3137 return;
3138
3139 raw_local_irq_save(flags);
3140 current->lockdep_recursion = 1;
3141 register_lock_class(lock, subclass, 1);
3142 current->lockdep_recursion = 0;
3143 raw_local_irq_restore(flags);
3144 }
3145}
3146EXPORT_SYMBOL_GPL(lockdep_init_map);
3147
3148struct lock_class_key __lockdep_no_validate__;
3149EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
3150
3151static int
3152print_lock_nested_lock_not_held(struct task_struct *curr,
3153 struct held_lock *hlock,
3154 unsigned long ip)
3155{
3156 if (!debug_locks_off())
3157 return 0;
3158 if (debug_locks_silent)
3159 return 0;
3160
3161 printk("\n");
3162 printk("==================================\n");
3163 printk("[ BUG: Nested lock was not taken ]\n");
3164 print_kernel_ident();
3165 printk("----------------------------------\n");
3166
3167 printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
3168 print_lock(hlock);
3169
3170 printk("\nbut this task is not holding:\n");
3171 printk("%s\n", hlock->nest_lock->name);
3172
3173 printk("\nstack backtrace:\n");
3174 dump_stack();
3175
3176 printk("\nother info that might help us debug this:\n");
3177 lockdep_print_held_locks(curr);
3178
3179 printk("\nstack backtrace:\n");
3180 dump_stack();
3181
3182 return 0;
3183}
3184
3185static int __lock_is_held(struct lockdep_map *lock);
3186
3187
3188
3189
3190
3191static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
3192 int trylock, int read, int check, int hardirqs_off,
3193 struct lockdep_map *nest_lock, unsigned long ip,
3194 int references, int pin_count)
3195{
3196 struct task_struct *curr = current;
3197 struct lock_class *class = NULL;
3198 struct held_lock *hlock;
3199 unsigned int depth;
3200 int chain_head = 0;
3201 int class_idx;
3202 u64 chain_key;
3203
3204 if (unlikely(!debug_locks))
3205 return 0;
3206
3207
3208
3209
3210
3211
3212 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3213 return 0;
3214
3215 if (!prove_locking || lock->key == &__lockdep_no_validate__)
3216 check = 0;
3217
3218 if (subclass < NR_LOCKDEP_CACHING_CLASSES)
3219 class = lock->class_cache[subclass];
3220
3221
3222
3223 if (unlikely(!class)) {
3224 class = register_lock_class(lock, subclass, 0);
3225 if (!class)
3226 return 0;
3227 }
3228 atomic_inc((atomic_t *)&class->ops);
3229 if (very_verbose(class)) {
3230 printk("\nacquire class [%p] %s", class->key, class->name);
3231 if (class->name_version > 1)
3232 printk("#%d", class->name_version);
3233 printk("\n");
3234 dump_stack();
3235 }
3236
3237
3238
3239
3240
3241
3242 depth = curr->lockdep_depth;
3243
3244
3245
3246 if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
3247 return 0;
3248
3249 class_idx = class - lock_classes + 1;
3250
3251 if (depth) {
3252 hlock = curr->held_locks + depth - 1;
3253 if (hlock->class_idx == class_idx && nest_lock) {
3254 if (hlock->references)
3255 hlock->references++;
3256 else
3257 hlock->references = 2;
3258
3259 return 1;
3260 }
3261 }
3262
3263 hlock = curr->held_locks + depth;
3264
3265
3266
3267
3268 if (DEBUG_LOCKS_WARN_ON(!class))
3269 return 0;
3270 hlock->class_idx = class_idx;
3271 hlock->acquire_ip = ip;
3272 hlock->instance = lock;
3273 hlock->nest_lock = nest_lock;
3274 hlock->irq_context = task_irq_context(curr);
3275 hlock->trylock = trylock;
3276 hlock->read = read;
3277 hlock->check = check;
3278 hlock->hardirqs_off = !!hardirqs_off;
3279 hlock->references = references;
3280#ifdef CONFIG_LOCK_STAT
3281 hlock->waittime_stamp = 0;
3282 hlock->holdtime_stamp = lockstat_clock();
3283#endif
3284 hlock->pin_count = pin_count;
3285
3286 if (check && !mark_irqflags(curr, hlock))
3287 return 0;
3288
3289
3290 if (!mark_lock(curr, hlock, LOCK_USED))
3291 return 0;
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306 if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS))
3307 return 0;
3308
3309 chain_key = curr->curr_chain_key;
3310 if (!depth) {
3311
3312
3313
3314 if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
3315 return 0;
3316 chain_head = 1;
3317 }
3318
3319 hlock->prev_chain_key = chain_key;
3320 if (separate_irq_context(curr, hlock)) {
3321 chain_key = 0;
3322 chain_head = 1;
3323 }
3324 chain_key = iterate_chain_key(chain_key, class_idx);
3325
3326 if (nest_lock && !__lock_is_held(nest_lock))
3327 return print_lock_nested_lock_not_held(curr, hlock, ip);
3328
3329 if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
3330 return 0;
3331
3332 curr->curr_chain_key = chain_key;
3333 curr->lockdep_depth++;
3334 check_chain_key(curr);
3335#ifdef CONFIG_DEBUG_LOCKDEP
3336 if (unlikely(!debug_locks))
3337 return 0;
3338#endif
3339 if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
3340 debug_locks_off();
3341 print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
3342 printk(KERN_DEBUG "depth: %i max: %lu!\n",
3343 curr->lockdep_depth, MAX_LOCK_DEPTH);
3344
3345 lockdep_print_held_locks(current);
3346 debug_show_all_locks();
3347 dump_stack();
3348
3349 return 0;
3350 }
3351
3352 if (unlikely(curr->lockdep_depth > max_lockdep_depth))
3353 max_lockdep_depth = curr->lockdep_depth;
3354
3355 return 1;
3356}
3357
3358static int
3359print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
3360 unsigned long ip)
3361{
3362 if (!debug_locks_off())
3363 return 0;
3364 if (debug_locks_silent)
3365 return 0;
3366
3367 printk("\n");
3368 printk("=====================================\n");
3369 printk("[ BUG: bad unlock balance detected! ]\n");
3370 print_kernel_ident();
3371 printk("-------------------------------------\n");
3372 printk("%s/%d is trying to release lock (",
3373 curr->comm, task_pid_nr(curr));
3374 print_lockdep_cache(lock);
3375 printk(") at:\n");
3376 print_ip_sym(ip);
3377 printk("but there are no more locks to release!\n");
3378 printk("\nother info that might help us debug this:\n");
3379 lockdep_print_held_locks(curr);
3380
3381 printk("\nstack backtrace:\n");
3382 dump_stack();
3383
3384 return 0;
3385}
3386
3387static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
3388{
3389 if (hlock->instance == lock)
3390 return 1;
3391
3392 if (hlock->references) {
3393 struct lock_class *class = lock->class_cache[0];
3394
3395 if (!class)
3396 class = look_up_lock_class(lock, 0);
3397
3398
3399
3400
3401
3402
3403
3404 if (!class)
3405 return 0;
3406
3407
3408
3409
3410
3411
3412 if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
3413 return 0;
3414
3415 if (hlock->class_idx == class - lock_classes + 1)
3416 return 1;
3417 }
3418
3419 return 0;
3420}
3421
3422static int
3423__lock_set_class(struct lockdep_map *lock, const char *name,
3424 struct lock_class_key *key, unsigned int subclass,
3425 unsigned long ip)
3426{
3427 struct task_struct *curr = current;
3428 struct held_lock *hlock, *prev_hlock;
3429 struct lock_class *class;
3430 unsigned int depth;
3431 int i;
3432
3433 depth = curr->lockdep_depth;
3434
3435
3436
3437
3438 if (DEBUG_LOCKS_WARN_ON(!depth))
3439 return 0;
3440
3441 prev_hlock = NULL;
3442 for (i = depth-1; i >= 0; i--) {
3443 hlock = curr->held_locks + i;
3444
3445
3446
3447 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3448 break;
3449 if (match_held_lock(hlock, lock))
3450 goto found_it;
3451 prev_hlock = hlock;
3452 }
3453 return print_unlock_imbalance_bug(curr, lock, ip);
3454
3455found_it:
3456 lockdep_init_map(lock, name, key, 0);
3457 class = register_lock_class(lock, subclass, 0);
3458 hlock->class_idx = class - lock_classes + 1;
3459
3460 curr->lockdep_depth = i;
3461 curr->curr_chain_key = hlock->prev_chain_key;
3462
3463 for (; i < depth; i++) {
3464 hlock = curr->held_locks + i;
3465 if (!__lock_acquire(hlock->instance,
3466 hlock_class(hlock)->subclass, hlock->trylock,
3467 hlock->read, hlock->check, hlock->hardirqs_off,
3468 hlock->nest_lock, hlock->acquire_ip,
3469 hlock->references, hlock->pin_count))
3470 return 0;
3471 }
3472
3473
3474
3475
3476
3477 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
3478 return 0;
3479 return 1;
3480}
3481
3482
3483
3484
3485
3486
3487
3488
3489static int
3490__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
3491{
3492 struct task_struct *curr = current;
3493 struct held_lock *hlock, *prev_hlock;
3494 unsigned int depth;
3495 int i;
3496
3497 if (unlikely(!debug_locks))
3498 return 0;
3499
3500 depth = curr->lockdep_depth;
3501
3502
3503
3504
3505 if (DEBUG_LOCKS_WARN_ON(depth <= 0))
3506 return print_unlock_imbalance_bug(curr, lock, ip);
3507
3508
3509
3510
3511
3512 prev_hlock = NULL;
3513 for (i = depth-1; i >= 0; i--) {
3514 hlock = curr->held_locks + i;
3515
3516
3517
3518 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3519 break;
3520 if (match_held_lock(hlock, lock))
3521 goto found_it;
3522 prev_hlock = hlock;
3523 }
3524 return print_unlock_imbalance_bug(curr, lock, ip);
3525
3526found_it:
3527 if (hlock->instance == lock)
3528 lock_release_holdtime(hlock);
3529
3530 WARN(hlock->pin_count, "releasing a pinned lock\n");
3531
3532 if (hlock->references) {
3533 hlock->references--;
3534 if (hlock->references) {
3535
3536
3537
3538
3539
3540 return 1;
3541 }
3542 }
3543
3544
3545
3546
3547
3548
3549
3550 curr->lockdep_depth = i;
3551 curr->curr_chain_key = hlock->prev_chain_key;
3552
3553 for (i++; i < depth; i++) {
3554 hlock = curr->held_locks + i;
3555 if (!__lock_acquire(hlock->instance,
3556 hlock_class(hlock)->subclass, hlock->trylock,
3557 hlock->read, hlock->check, hlock->hardirqs_off,
3558 hlock->nest_lock, hlock->acquire_ip,
3559 hlock->references, hlock->pin_count))
3560 return 0;
3561 }
3562
3563
3564
3565
3566
3567 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
3568 return 0;
3569
3570 return 1;
3571}
3572
3573static int __lock_is_held(struct lockdep_map *lock)
3574{
3575 struct task_struct *curr = current;
3576 int i;
3577
3578 for (i = 0; i < curr->lockdep_depth; i++) {
3579 struct held_lock *hlock = curr->held_locks + i;
3580
3581 if (match_held_lock(hlock, lock))
3582 return 1;
3583 }
3584
3585 return 0;
3586}
3587
3588static void __lock_pin_lock(struct lockdep_map *lock)
3589{
3590 struct task_struct *curr = current;
3591 int i;
3592
3593 if (unlikely(!debug_locks))
3594 return;
3595
3596 for (i = 0; i < curr->lockdep_depth; i++) {
3597 struct held_lock *hlock = curr->held_locks + i;
3598
3599 if (match_held_lock(hlock, lock)) {
3600 hlock->pin_count++;
3601 return;
3602 }
3603 }
3604
3605 WARN(1, "pinning an unheld lock\n");
3606}
3607
3608static void __lock_unpin_lock(struct lockdep_map *lock)
3609{
3610 struct task_struct *curr = current;
3611 int i;
3612
3613 if (unlikely(!debug_locks))
3614 return;
3615
3616 for (i = 0; i < curr->lockdep_depth; i++) {
3617 struct held_lock *hlock = curr->held_locks + i;
3618
3619 if (match_held_lock(hlock, lock)) {
3620 if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
3621 return;
3622
3623 hlock->pin_count--;
3624 return;
3625 }
3626 }
3627
3628 WARN(1, "unpinning an unheld lock\n");
3629}
3630
3631
3632
3633
3634static void check_flags(unsigned long flags)
3635{
3636#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
3637 defined(CONFIG_TRACE_IRQFLAGS)
3638 if (!debug_locks)
3639 return;
3640
3641 if (irqs_disabled_flags(flags)) {
3642 if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
3643 printk("possible reason: unannotated irqs-off.\n");
3644 }
3645 } else {
3646 if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
3647 printk("possible reason: unannotated irqs-on.\n");
3648 }
3649 }
3650
3651
3652
3653
3654
3655
3656 if (!hardirq_count()) {
3657 if (softirq_count()) {
3658
3659 DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
3660 } else {
3661
3662 DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
3663 }
3664 }
3665
3666 if (!debug_locks)
3667 print_irqtrace_events(current);
3668#endif
3669}
3670
3671void lock_set_class(struct lockdep_map *lock, const char *name,
3672 struct lock_class_key *key, unsigned int subclass,
3673 unsigned long ip)
3674{
3675 unsigned long flags;
3676
3677 if (unlikely(current->lockdep_recursion))
3678 return;
3679
3680 raw_local_irq_save(flags);
3681 current->lockdep_recursion = 1;
3682 check_flags(flags);
3683 if (__lock_set_class(lock, name, key, subclass, ip))
3684 check_chain_key(current);
3685 current->lockdep_recursion = 0;
3686 raw_local_irq_restore(flags);
3687}
3688EXPORT_SYMBOL_GPL(lock_set_class);
3689
3690
3691
3692
3693
3694void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
3695 int trylock, int read, int check,
3696 struct lockdep_map *nest_lock, unsigned long ip)
3697{
3698 unsigned long flags;
3699
3700 if (unlikely(current->lockdep_recursion))
3701 return;
3702
3703 raw_local_irq_save(flags);
3704 check_flags(flags);
3705
3706 current->lockdep_recursion = 1;
3707 trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
3708 __lock_acquire(lock, subclass, trylock, read, check,
3709 irqs_disabled_flags(flags), nest_lock, ip, 0, 0);
3710 current->lockdep_recursion = 0;
3711 raw_local_irq_restore(flags);
3712}
3713EXPORT_SYMBOL_GPL(lock_acquire);
3714
3715void lock_release(struct lockdep_map *lock, int nested,
3716 unsigned long ip)
3717{
3718 unsigned long flags;
3719
3720 if (unlikely(current->lockdep_recursion))
3721 return;
3722
3723 raw_local_irq_save(flags);
3724 check_flags(flags);
3725 current->lockdep_recursion = 1;
3726 trace_lock_release(lock, ip);
3727 if (__lock_release(lock, nested, ip))
3728 check_chain_key(current);
3729 current->lockdep_recursion = 0;
3730 raw_local_irq_restore(flags);
3731}
3732EXPORT_SYMBOL_GPL(lock_release);
3733
3734int lock_is_held(struct lockdep_map *lock)
3735{
3736 unsigned long flags;
3737 int ret = 0;
3738
3739 if (unlikely(current->lockdep_recursion))
3740 return 1;
3741
3742 raw_local_irq_save(flags);
3743 check_flags(flags);
3744
3745 current->lockdep_recursion = 1;
3746 ret = __lock_is_held(lock);
3747 current->lockdep_recursion = 0;
3748 raw_local_irq_restore(flags);
3749
3750 return ret;
3751}
3752EXPORT_SYMBOL_GPL(lock_is_held);
3753
3754void lock_pin_lock(struct lockdep_map *lock)
3755{
3756 unsigned long flags;
3757
3758 if (unlikely(current->lockdep_recursion))
3759 return;
3760
3761 raw_local_irq_save(flags);
3762 check_flags(flags);
3763
3764 current->lockdep_recursion = 1;
3765 __lock_pin_lock(lock);
3766 current->lockdep_recursion = 0;
3767 raw_local_irq_restore(flags);
3768}
3769EXPORT_SYMBOL_GPL(lock_pin_lock);
3770
3771void lock_unpin_lock(struct lockdep_map *lock)
3772{
3773 unsigned long flags;
3774
3775 if (unlikely(current->lockdep_recursion))
3776 return;
3777
3778 raw_local_irq_save(flags);
3779 check_flags(flags);
3780
3781 current->lockdep_recursion = 1;
3782 __lock_unpin_lock(lock);
3783 current->lockdep_recursion = 0;
3784 raw_local_irq_restore(flags);
3785}
3786EXPORT_SYMBOL_GPL(lock_unpin_lock);
3787
3788void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
3789{
3790 current->lockdep_reclaim_gfp = gfp_mask;
3791}
3792
3793void lockdep_clear_current_reclaim_state(void)
3794{
3795 current->lockdep_reclaim_gfp = 0;
3796}
3797
3798#ifdef CONFIG_LOCK_STAT
3799static int
3800print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
3801 unsigned long ip)
3802{
3803 if (!debug_locks_off())
3804 return 0;
3805 if (debug_locks_silent)
3806 return 0;
3807
3808 printk("\n");
3809 printk("=================================\n");
3810 printk("[ BUG: bad contention detected! ]\n");
3811 print_kernel_ident();
3812 printk("---------------------------------\n");
3813 printk("%s/%d is trying to contend lock (",
3814 curr->comm, task_pid_nr(curr));
3815 print_lockdep_cache(lock);
3816 printk(") at:\n");
3817 print_ip_sym(ip);
3818 printk("but there are no locks held!\n");
3819 printk("\nother info that might help us debug this:\n");
3820 lockdep_print_held_locks(curr);
3821
3822 printk("\nstack backtrace:\n");
3823 dump_stack();
3824
3825 return 0;
3826}
3827
3828static void
3829__lock_contended(struct lockdep_map *lock, unsigned long ip)
3830{
3831 struct task_struct *curr = current;
3832 struct held_lock *hlock, *prev_hlock;
3833 struct lock_class_stats *stats;
3834 unsigned int depth;
3835 int i, contention_point, contending_point;
3836
3837 depth = curr->lockdep_depth;
3838
3839
3840
3841
3842 if (DEBUG_LOCKS_WARN_ON(!depth))
3843 return;
3844
3845 prev_hlock = NULL;
3846 for (i = depth-1; i >= 0; i--) {
3847 hlock = curr->held_locks + i;
3848
3849
3850
3851 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3852 break;
3853 if (match_held_lock(hlock, lock))
3854 goto found_it;
3855 prev_hlock = hlock;
3856 }
3857 print_lock_contention_bug(curr, lock, ip);
3858 return;
3859
3860found_it:
3861 if (hlock->instance != lock)
3862 return;
3863
3864 hlock->waittime_stamp = lockstat_clock();
3865
3866 contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
3867 contending_point = lock_point(hlock_class(hlock)->contending_point,
3868 lock->ip);
3869
3870 stats = get_lock_stats(hlock_class(hlock));
3871 if (contention_point < LOCKSTAT_POINTS)
3872 stats->contention_point[contention_point]++;
3873 if (contending_point < LOCKSTAT_POINTS)
3874 stats->contending_point[contending_point]++;
3875 if (lock->cpu != smp_processor_id())
3876 stats->bounces[bounce_contended + !!hlock->read]++;
3877 put_lock_stats(stats);
3878}
3879
3880static void
3881__lock_acquired(struct lockdep_map *lock, unsigned long ip)
3882{
3883 struct task_struct *curr = current;
3884 struct held_lock *hlock, *prev_hlock;
3885 struct lock_class_stats *stats;
3886 unsigned int depth;
3887 u64 now, waittime = 0;
3888 int i, cpu;
3889
3890 depth = curr->lockdep_depth;
3891
3892
3893
3894
3895 if (DEBUG_LOCKS_WARN_ON(!depth))
3896 return;
3897
3898 prev_hlock = NULL;
3899 for (i = depth-1; i >= 0; i--) {
3900 hlock = curr->held_locks + i;
3901
3902
3903
3904 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3905 break;
3906 if (match_held_lock(hlock, lock))
3907 goto found_it;
3908 prev_hlock = hlock;
3909 }
3910 print_lock_contention_bug(curr, lock, _RET_IP_);
3911 return;
3912
3913found_it:
3914 if (hlock->instance != lock)
3915 return;
3916
3917 cpu = smp_processor_id();
3918 if (hlock->waittime_stamp) {
3919 now = lockstat_clock();
3920 waittime = now - hlock->waittime_stamp;
3921 hlock->holdtime_stamp = now;
3922 }
3923
3924 trace_lock_acquired(lock, ip);
3925
3926 stats = get_lock_stats(hlock_class(hlock));
3927 if (waittime) {
3928 if (hlock->read)
3929 lock_time_inc(&stats->read_waittime, waittime);
3930 else
3931 lock_time_inc(&stats->write_waittime, waittime);
3932 }
3933 if (lock->cpu != cpu)
3934 stats->bounces[bounce_acquired + !!hlock->read]++;
3935 put_lock_stats(stats);
3936
3937 lock->cpu = cpu;
3938 lock->ip = ip;
3939}
3940
3941void lock_contended(struct lockdep_map *lock, unsigned long ip)
3942{
3943 unsigned long flags;
3944
3945 if (unlikely(!lock_stat))
3946 return;
3947
3948 if (unlikely(current->lockdep_recursion))
3949 return;
3950
3951 raw_local_irq_save(flags);
3952 check_flags(flags);
3953 current->lockdep_recursion = 1;
3954 trace_lock_contended(lock, ip);
3955 __lock_contended(lock, ip);
3956 current->lockdep_recursion = 0;
3957 raw_local_irq_restore(flags);
3958}
3959EXPORT_SYMBOL_GPL(lock_contended);
3960
3961void lock_acquired(struct lockdep_map *lock, unsigned long ip)
3962{
3963 unsigned long flags;
3964
3965 if (unlikely(!lock_stat))
3966 return;
3967
3968 if (unlikely(current->lockdep_recursion))
3969 return;
3970
3971 raw_local_irq_save(flags);
3972 check_flags(flags);
3973 current->lockdep_recursion = 1;
3974 __lock_acquired(lock, ip);
3975 current->lockdep_recursion = 0;
3976 raw_local_irq_restore(flags);
3977}
3978EXPORT_SYMBOL_GPL(lock_acquired);
3979#endif
3980
3981
3982
3983
3984
3985
3986void lockdep_reset(void)
3987{
3988 unsigned long flags;
3989 int i;
3990
3991 raw_local_irq_save(flags);
3992 current->curr_chain_key = 0;
3993 current->lockdep_depth = 0;
3994 current->lockdep_recursion = 0;
3995 memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
3996 nr_hardirq_chains = 0;
3997 nr_softirq_chains = 0;
3998 nr_process_chains = 0;
3999 debug_locks = 1;
4000 for (i = 0; i < CHAINHASH_SIZE; i++)
4001 INIT_HLIST_HEAD(chainhash_table + i);
4002 raw_local_irq_restore(flags);
4003}
4004
4005static void zap_class(struct lock_class *class)
4006{
4007 int i;
4008
4009
4010
4011
4012
4013 for (i = 0; i < nr_list_entries; i++) {
4014 if (list_entries[i].class == class)
4015 list_del_rcu(&list_entries[i].entry);
4016 }
4017
4018
4019
4020 hlist_del_rcu(&class->hash_entry);
4021 list_del_rcu(&class->lock_entry);
4022
4023 RCU_INIT_POINTER(class->key, NULL);
4024 RCU_INIT_POINTER(class->name, NULL);
4025}
4026
4027static inline int within(const void *addr, void *start, unsigned long size)
4028{
4029 return addr >= start && addr < start + size;
4030}
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040void lockdep_free_key_range(void *start, unsigned long size)
4041{
4042 struct lock_class *class;
4043 struct hlist_head *head;
4044 unsigned long flags;
4045 int i;
4046 int locked;
4047
4048 raw_local_irq_save(flags);
4049 locked = graph_lock();
4050
4051
4052
4053
4054 for (i = 0; i < CLASSHASH_SIZE; i++) {
4055 head = classhash_table + i;
4056 hlist_for_each_entry_rcu(class, head, hash_entry) {
4057 if (within(class->key, start, size))
4058 zap_class(class);
4059 else if (within(class->name, start, size))
4060 zap_class(class);
4061 }
4062 }
4063
4064 if (locked)
4065 graph_unlock();
4066 raw_local_irq_restore(flags);
4067
4068
4069
4070
4071
4072
4073
4074 synchronize_sched();
4075
4076
4077
4078
4079
4080
4081}
4082
4083void lockdep_reset_lock(struct lockdep_map *lock)
4084{
4085 struct lock_class *class;
4086 struct hlist_head *head;
4087 unsigned long flags;
4088 int i, j;
4089 int locked;
4090
4091 raw_local_irq_save(flags);
4092
4093
4094
4095
4096 for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
4097
4098
4099
4100 class = look_up_lock_class(lock, j);
4101 if (class)
4102 zap_class(class);
4103 }
4104
4105
4106
4107
4108 locked = graph_lock();
4109 for (i = 0; i < CLASSHASH_SIZE; i++) {
4110 head = classhash_table + i;
4111 hlist_for_each_entry_rcu(class, head, hash_entry) {
4112 int match = 0;
4113
4114 for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
4115 match |= class == lock->class_cache[j];
4116
4117 if (unlikely(match)) {
4118 if (debug_locks_off_graph_unlock()) {
4119
4120
4121
4122 WARN_ON(1);
4123 }
4124 goto out_restore;
4125 }
4126 }
4127 }
4128 if (locked)
4129 graph_unlock();
4130
4131out_restore:
4132 raw_local_irq_restore(flags);
4133}
4134
4135void __init lockdep_info(void)
4136{
4137 printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
4138
4139 printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
4140 printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
4141 printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
4142 printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
4143 printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
4144 printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
4145 printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
4146
4147 printk(" memory used by lock dependency info: %lu kB\n",
4148 (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
4149 sizeof(struct list_head) * CLASSHASH_SIZE +
4150 sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
4151 sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
4152 sizeof(struct list_head) * CHAINHASH_SIZE
4153#ifdef CONFIG_PROVE_LOCKING
4154 + sizeof(struct circular_queue)
4155#endif
4156 ) / 1024
4157 );
4158
4159 printk(" per task-struct memory footprint: %lu bytes\n",
4160 sizeof(struct held_lock) * MAX_LOCK_DEPTH);
4161}
4162
4163static void
4164print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
4165 const void *mem_to, struct held_lock *hlock)
4166{
4167 if (!debug_locks_off())
4168 return;
4169 if (debug_locks_silent)
4170 return;
4171
4172 printk("\n");
4173 printk("=========================\n");
4174 printk("[ BUG: held lock freed! ]\n");
4175 print_kernel_ident();
4176 printk("-------------------------\n");
4177 printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
4178 curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
4179 print_lock(hlock);
4180 lockdep_print_held_locks(curr);
4181
4182 printk("\nstack backtrace:\n");
4183 dump_stack();
4184}
4185
4186static inline int not_in_range(const void* mem_from, unsigned long mem_len,
4187 const void* lock_from, unsigned long lock_len)
4188{
4189 return lock_from + lock_len <= mem_from ||
4190 mem_from + mem_len <= lock_from;
4191}
4192
4193
4194
4195
4196
4197
4198void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
4199{
4200 struct task_struct *curr = current;
4201 struct held_lock *hlock;
4202 unsigned long flags;
4203 int i;
4204
4205 if (unlikely(!debug_locks))
4206 return;
4207
4208 local_irq_save(flags);
4209 for (i = 0; i < curr->lockdep_depth; i++) {
4210 hlock = curr->held_locks + i;
4211
4212 if (not_in_range(mem_from, mem_len, hlock->instance,
4213 sizeof(*hlock->instance)))
4214 continue;
4215
4216 print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
4217 break;
4218 }
4219 local_irq_restore(flags);
4220}
4221EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
4222
4223static void print_held_locks_bug(void)
4224{
4225 if (!debug_locks_off())
4226 return;
4227 if (debug_locks_silent)
4228 return;
4229
4230 printk("\n");
4231 printk("=====================================\n");
4232 printk("[ BUG: %s/%d still has locks held! ]\n",
4233 current->comm, task_pid_nr(current));
4234 print_kernel_ident();
4235 printk("-------------------------------------\n");
4236 lockdep_print_held_locks(current);
4237 printk("\nstack backtrace:\n");
4238 dump_stack();
4239}
4240
4241void debug_check_no_locks_held(void)
4242{
4243 if (unlikely(current->lockdep_depth > 0))
4244 print_held_locks_bug();
4245}
4246EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
4247
4248#ifdef __KERNEL__
4249void debug_show_all_locks(void)
4250{
4251 struct task_struct *g, *p;
4252 int count = 10;
4253 int unlock = 1;
4254
4255 if (unlikely(!debug_locks)) {
4256 printk("INFO: lockdep is turned off.\n");
4257 return;
4258 }
4259 printk("\nShowing all locks held in the system:\n");
4260
4261
4262
4263
4264
4265
4266
4267retry:
4268 if (!read_trylock(&tasklist_lock)) {
4269 if (count == 10)
4270 printk("hm, tasklist_lock locked, retrying... ");
4271 if (count) {
4272 count--;
4273 printk(" #%d", 10-count);
4274 mdelay(200);
4275 goto retry;
4276 }
4277 printk(" ignoring it.\n");
4278 unlock = 0;
4279 } else {
4280 if (count != 10)
4281 printk(KERN_CONT " locked it.\n");
4282 }
4283
4284 do_each_thread(g, p) {
4285
4286
4287
4288
4289
4290 if (p->state == TASK_RUNNING && p != current)
4291 continue;
4292 if (p->lockdep_depth)
4293 lockdep_print_held_locks(p);
4294 if (!unlock)
4295 if (read_trylock(&tasklist_lock))
4296 unlock = 1;
4297 } while_each_thread(g, p);
4298
4299 printk("\n");
4300 printk("=============================================\n\n");
4301
4302 if (unlock)
4303 read_unlock(&tasklist_lock);
4304}
4305EXPORT_SYMBOL_GPL(debug_show_all_locks);
4306#endif
4307
4308
4309
4310
4311
4312void debug_show_held_locks(struct task_struct *task)
4313{
4314 if (unlikely(!debug_locks)) {
4315 printk("INFO: lockdep is turned off.\n");
4316 return;
4317 }
4318 lockdep_print_held_locks(task);
4319}
4320EXPORT_SYMBOL_GPL(debug_show_held_locks);
4321
4322asmlinkage __visible void lockdep_sys_exit(void)
4323{
4324 struct task_struct *curr = current;
4325
4326 if (unlikely(curr->lockdep_depth)) {
4327 if (!debug_locks_off())
4328 return;
4329 printk("\n");
4330 printk("================================================\n");
4331 printk("[ BUG: lock held when returning to user space! ]\n");
4332 print_kernel_ident();
4333 printk("------------------------------------------------\n");
4334 printk("%s/%d is leaving the kernel with locks still held!\n",
4335 curr->comm, curr->pid);
4336 lockdep_print_held_locks(curr);
4337 }
4338}
4339
4340void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
4341{
4342 struct task_struct *curr = current;
4343
4344#ifndef CONFIG_PROVE_RCU_REPEATEDLY
4345 if (!debug_locks_off())
4346 return;
4347#endif
4348
4349 printk("\n");
4350 printk("===============================\n");
4351 printk("[ INFO: suspicious RCU usage. ]\n");
4352 print_kernel_ident();
4353 printk("-------------------------------\n");
4354 printk("%s:%d %s!\n", file, line, s);
4355 printk("\nother info that might help us debug this:\n\n");
4356 printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
4357 !rcu_lockdep_current_cpu_online()
4358 ? "RCU used illegally from offline CPU!\n"
4359 : !rcu_is_watching()
4360 ? "RCU used illegally from idle CPU!\n"
4361 : "",
4362 rcu_scheduler_active, debug_locks);
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382 if (!rcu_is_watching())
4383 printk("RCU used illegally from extended quiescent state!\n");
4384
4385 lockdep_print_held_locks(curr);
4386 printk("\nstack backtrace:\n");
4387 dump_stack();
4388}
4389EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
4390