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28
29#define DISABLE_BRANCH_PROFILING
30#include <linux/mutex.h>
31#include <linux/sched.h>
32#include <linux/sched/clock.h>
33#include <linux/sched/task.h>
34#include <linux/sched/mm.h>
35#include <linux/delay.h>
36#include <linux/module.h>
37#include <linux/proc_fs.h>
38#include <linux/seq_file.h>
39#include <linux/spinlock.h>
40#include <linux/kallsyms.h>
41#include <linux/interrupt.h>
42#include <linux/stacktrace.h>
43#include <linux/debug_locks.h>
44#include <linux/irqflags.h>
45#include <linux/utsname.h>
46#include <linux/hash.h>
47#include <linux/ftrace.h>
48#include <linux/stringify.h>
49#include <linux/bitmap.h>
50#include <linux/bitops.h>
51#include <linux/gfp.h>
52#include <linux/random.h>
53#include <linux/jhash.h>
54#include <linux/nmi.h>
55#include <linux/rcupdate.h>
56#include <linux/kprobes.h>
57
58#include <asm/sections.h>
59
60#include "lockdep_internals.h"
61
62#define CREATE_TRACE_POINTS
63#include <trace/events/lock.h>
64
65#ifdef CONFIG_PROVE_LOCKING
66int prove_locking = 1;
67module_param(prove_locking, int, 0644);
68#else
69#define prove_locking 0
70#endif
71
72#ifdef CONFIG_LOCK_STAT
73int lock_stat = 1;
74module_param(lock_stat, int, 0644);
75#else
76#define lock_stat 0
77#endif
78
79
80
81
82
83
84
85
86
87static arch_spinlock_t __lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
88static struct task_struct *__owner;
89
90static inline void lockdep_lock(void)
91{
92 DEBUG_LOCKS_WARN_ON(!irqs_disabled());
93
94 arch_spin_lock(&__lock);
95 __owner = current;
96 current->lockdep_recursion++;
97}
98
99static inline void lockdep_unlock(void)
100{
101 if (debug_locks && DEBUG_LOCKS_WARN_ON(__owner != current))
102 return;
103
104 current->lockdep_recursion--;
105 __owner = NULL;
106 arch_spin_unlock(&__lock);
107}
108
109static inline bool lockdep_assert_locked(void)
110{
111 return DEBUG_LOCKS_WARN_ON(__owner != current);
112}
113
114static struct task_struct *lockdep_selftest_task_struct;
115
116
117static int graph_lock(void)
118{
119 lockdep_lock();
120
121
122
123
124
125
126 if (!debug_locks) {
127 lockdep_unlock();
128 return 0;
129 }
130 return 1;
131}
132
133static inline void graph_unlock(void)
134{
135 lockdep_unlock();
136}
137
138
139
140
141
142static inline int debug_locks_off_graph_unlock(void)
143{
144 int ret = debug_locks_off();
145
146 lockdep_unlock();
147
148 return ret;
149}
150
151unsigned long nr_list_entries;
152static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
153static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES);
154
155
156
157
158
159
160
161#define KEYHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
162#define KEYHASH_SIZE (1UL << KEYHASH_BITS)
163static struct hlist_head lock_keys_hash[KEYHASH_SIZE];
164unsigned long nr_lock_classes;
165unsigned long nr_zapped_classes;
166#ifndef CONFIG_DEBUG_LOCKDEP
167static
168#endif
169struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
170static DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS);
171
172static inline struct lock_class *hlock_class(struct held_lock *hlock)
173{
174 unsigned int class_idx = hlock->class_idx;
175
176
177 barrier();
178
179 if (!test_bit(class_idx, lock_classes_in_use)) {
180
181
182
183 DEBUG_LOCKS_WARN_ON(1);
184 return NULL;
185 }
186
187
188
189
190
191 return lock_classes + class_idx;
192}
193
194#ifdef CONFIG_LOCK_STAT
195static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats);
196
197static inline u64 lockstat_clock(void)
198{
199 return local_clock();
200}
201
202static int lock_point(unsigned long points[], unsigned long ip)
203{
204 int i;
205
206 for (i = 0; i < LOCKSTAT_POINTS; i++) {
207 if (points[i] == 0) {
208 points[i] = ip;
209 break;
210 }
211 if (points[i] == ip)
212 break;
213 }
214
215 return i;
216}
217
218static void lock_time_inc(struct lock_time *lt, u64 time)
219{
220 if (time > lt->max)
221 lt->max = time;
222
223 if (time < lt->min || !lt->nr)
224 lt->min = time;
225
226 lt->total += time;
227 lt->nr++;
228}
229
230static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
231{
232 if (!src->nr)
233 return;
234
235 if (src->max > dst->max)
236 dst->max = src->max;
237
238 if (src->min < dst->min || !dst->nr)
239 dst->min = src->min;
240
241 dst->total += src->total;
242 dst->nr += src->nr;
243}
244
245struct lock_class_stats lock_stats(struct lock_class *class)
246{
247 struct lock_class_stats stats;
248 int cpu, i;
249
250 memset(&stats, 0, sizeof(struct lock_class_stats));
251 for_each_possible_cpu(cpu) {
252 struct lock_class_stats *pcs =
253 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
254
255 for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
256 stats.contention_point[i] += pcs->contention_point[i];
257
258 for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
259 stats.contending_point[i] += pcs->contending_point[i];
260
261 lock_time_add(&pcs->read_waittime, &stats.read_waittime);
262 lock_time_add(&pcs->write_waittime, &stats.write_waittime);
263
264 lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
265 lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
266
267 for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
268 stats.bounces[i] += pcs->bounces[i];
269 }
270
271 return stats;
272}
273
274void clear_lock_stats(struct lock_class *class)
275{
276 int cpu;
277
278 for_each_possible_cpu(cpu) {
279 struct lock_class_stats *cpu_stats =
280 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
281
282 memset(cpu_stats, 0, sizeof(struct lock_class_stats));
283 }
284 memset(class->contention_point, 0, sizeof(class->contention_point));
285 memset(class->contending_point, 0, sizeof(class->contending_point));
286}
287
288static struct lock_class_stats *get_lock_stats(struct lock_class *class)
289{
290 return &this_cpu_ptr(cpu_lock_stats)[class - lock_classes];
291}
292
293static void lock_release_holdtime(struct held_lock *hlock)
294{
295 struct lock_class_stats *stats;
296 u64 holdtime;
297
298 if (!lock_stat)
299 return;
300
301 holdtime = lockstat_clock() - hlock->holdtime_stamp;
302
303 stats = get_lock_stats(hlock_class(hlock));
304 if (hlock->read)
305 lock_time_inc(&stats->read_holdtime, holdtime);
306 else
307 lock_time_inc(&stats->write_holdtime, holdtime);
308}
309#else
310static inline void lock_release_holdtime(struct held_lock *hlock)
311{
312}
313#endif
314
315
316
317
318
319
320
321LIST_HEAD(all_lock_classes);
322static LIST_HEAD(free_lock_classes);
323
324
325
326
327
328
329
330struct pending_free {
331 struct list_head zapped;
332 DECLARE_BITMAP(lock_chains_being_freed, MAX_LOCKDEP_CHAINS);
333};
334
335
336
337
338
339
340
341
342
343
344
345
346static struct delayed_free {
347 struct rcu_head rcu_head;
348 int index;
349 int scheduled;
350 struct pending_free pf[2];
351} delayed_free;
352
353
354
355
356#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
357#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
358#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
359#define classhashentry(key) (classhash_table + __classhashfn((key)))
360
361static struct hlist_head classhash_table[CLASSHASH_SIZE];
362
363
364
365
366
367#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
368#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
369#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
370#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
371
372static struct hlist_head chainhash_table[CHAINHASH_SIZE];
373
374
375
376
377
378
379
380static inline u64 iterate_chain_key(u64 key, u32 idx)
381{
382 u32 k0 = key, k1 = key >> 32;
383
384 __jhash_mix(idx, k0, k1);
385
386 return k0 | (u64)k1 << 32;
387}
388
389void lockdep_init_task(struct task_struct *task)
390{
391 task->lockdep_depth = 0;
392 task->curr_chain_key = INITIAL_CHAIN_KEY;
393 task->lockdep_recursion = 0;
394}
395
396static __always_inline void lockdep_recursion_finish(void)
397{
398 if (WARN_ON_ONCE((--current->lockdep_recursion) & LOCKDEP_RECURSION_MASK))
399 current->lockdep_recursion = 0;
400}
401
402void lockdep_set_selftest_task(struct task_struct *task)
403{
404 lockdep_selftest_task_struct = task;
405}
406
407
408
409
410
411#define VERBOSE 0
412#define VERY_VERBOSE 0
413
414#if VERBOSE
415# define HARDIRQ_VERBOSE 1
416# define SOFTIRQ_VERBOSE 1
417#else
418# define HARDIRQ_VERBOSE 0
419# define SOFTIRQ_VERBOSE 0
420#endif
421
422#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
423
424
425
426static int class_filter(struct lock_class *class)
427{
428#if 0
429
430 if (class->name_version == 1 &&
431 !strcmp(class->name, "lockname"))
432 return 1;
433 if (class->name_version == 1 &&
434 !strcmp(class->name, "&struct->lockfield"))
435 return 1;
436#endif
437
438 return 0;
439}
440#endif
441
442static int verbose(struct lock_class *class)
443{
444#if VERBOSE
445 return class_filter(class);
446#endif
447 return 0;
448}
449
450static void print_lockdep_off(const char *bug_msg)
451{
452 printk(KERN_DEBUG "%s\n", bug_msg);
453 printk(KERN_DEBUG "turning off the locking correctness validator.\n");
454#ifdef CONFIG_LOCK_STAT
455 printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
456#endif
457}
458
459unsigned long nr_stack_trace_entries;
460
461#ifdef CONFIG_PROVE_LOCKING
462
463
464
465
466
467
468
469struct lock_trace {
470 struct hlist_node hash_entry;
471 u32 hash;
472 u32 nr_entries;
473 unsigned long entries[] __aligned(sizeof(unsigned long));
474};
475#define LOCK_TRACE_SIZE_IN_LONGS \
476 (sizeof(struct lock_trace) / sizeof(unsigned long))
477
478
479
480static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
481static struct hlist_head stack_trace_hash[STACK_TRACE_HASH_SIZE];
482
483static bool traces_identical(struct lock_trace *t1, struct lock_trace *t2)
484{
485 return t1->hash == t2->hash && t1->nr_entries == t2->nr_entries &&
486 memcmp(t1->entries, t2->entries,
487 t1->nr_entries * sizeof(t1->entries[0])) == 0;
488}
489
490static struct lock_trace *save_trace(void)
491{
492 struct lock_trace *trace, *t2;
493 struct hlist_head *hash_head;
494 u32 hash;
495 int max_entries;
496
497 BUILD_BUG_ON_NOT_POWER_OF_2(STACK_TRACE_HASH_SIZE);
498 BUILD_BUG_ON(LOCK_TRACE_SIZE_IN_LONGS >= MAX_STACK_TRACE_ENTRIES);
499
500 trace = (struct lock_trace *)(stack_trace + nr_stack_trace_entries);
501 max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries -
502 LOCK_TRACE_SIZE_IN_LONGS;
503
504 if (max_entries <= 0) {
505 if (!debug_locks_off_graph_unlock())
506 return NULL;
507
508 print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
509 dump_stack();
510
511 return NULL;
512 }
513 trace->nr_entries = stack_trace_save(trace->entries, max_entries, 3);
514
515 hash = jhash(trace->entries, trace->nr_entries *
516 sizeof(trace->entries[0]), 0);
517 trace->hash = hash;
518 hash_head = stack_trace_hash + (hash & (STACK_TRACE_HASH_SIZE - 1));
519 hlist_for_each_entry(t2, hash_head, hash_entry) {
520 if (traces_identical(trace, t2))
521 return t2;
522 }
523 nr_stack_trace_entries += LOCK_TRACE_SIZE_IN_LONGS + trace->nr_entries;
524 hlist_add_head(&trace->hash_entry, hash_head);
525
526 return trace;
527}
528
529
530u64 lockdep_stack_trace_count(void)
531{
532 struct lock_trace *trace;
533 u64 c = 0;
534 int i;
535
536 for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++) {
537 hlist_for_each_entry(trace, &stack_trace_hash[i], hash_entry) {
538 c++;
539 }
540 }
541
542 return c;
543}
544
545
546u64 lockdep_stack_hash_count(void)
547{
548 u64 c = 0;
549 int i;
550
551 for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++)
552 if (!hlist_empty(&stack_trace_hash[i]))
553 c++;
554
555 return c;
556}
557#endif
558
559unsigned int nr_hardirq_chains;
560unsigned int nr_softirq_chains;
561unsigned int nr_process_chains;
562unsigned int max_lockdep_depth;
563
564#ifdef CONFIG_DEBUG_LOCKDEP
565
566
567
568DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
569#endif
570
571#ifdef CONFIG_PROVE_LOCKING
572
573
574
575
576#define __USAGE(__STATE) \
577 [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
578 [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
579 [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
580 [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
581
582static const char *usage_str[] =
583{
584#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
585#include "lockdep_states.h"
586#undef LOCKDEP_STATE
587 [LOCK_USED] = "INITIAL USE",
588 [LOCK_USAGE_STATES] = "IN-NMI",
589};
590#endif
591
592const char *__get_key_name(const struct lockdep_subclass_key *key, char *str)
593{
594 return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
595}
596
597static inline unsigned long lock_flag(enum lock_usage_bit bit)
598{
599 return 1UL << bit;
600}
601
602static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
603{
604
605
606
607
608 char c = '.';
609
610
611
612
613
614
615
616
617
618 if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) {
619 c = '+';
620 if (class->usage_mask & lock_flag(bit))
621 c = '?';
622 } else if (class->usage_mask & lock_flag(bit))
623 c = '-';
624
625 return c;
626}
627
628void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
629{
630 int i = 0;
631
632#define LOCKDEP_STATE(__STATE) \
633 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
634 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
635#include "lockdep_states.h"
636#undef LOCKDEP_STATE
637
638 usage[i] = '\0';
639}
640
641static void __print_lock_name(struct lock_class *class)
642{
643 char str[KSYM_NAME_LEN];
644 const char *name;
645
646 name = class->name;
647 if (!name) {
648 name = __get_key_name(class->key, str);
649 printk(KERN_CONT "%s", name);
650 } else {
651 printk(KERN_CONT "%s", name);
652 if (class->name_version > 1)
653 printk(KERN_CONT "#%d", class->name_version);
654 if (class->subclass)
655 printk(KERN_CONT "/%d", class->subclass);
656 }
657}
658
659static void print_lock_name(struct lock_class *class)
660{
661 char usage[LOCK_USAGE_CHARS];
662
663 get_usage_chars(class, usage);
664
665 printk(KERN_CONT " (");
666 __print_lock_name(class);
667 printk(KERN_CONT "){%s}-{%hd:%hd}", usage,
668 class->wait_type_outer ?: class->wait_type_inner,
669 class->wait_type_inner);
670}
671
672static void print_lockdep_cache(struct lockdep_map *lock)
673{
674 const char *name;
675 char str[KSYM_NAME_LEN];
676
677 name = lock->name;
678 if (!name)
679 name = __get_key_name(lock->key->subkeys, str);
680
681 printk(KERN_CONT "%s", name);
682}
683
684static void print_lock(struct held_lock *hlock)
685{
686
687
688
689
690
691
692
693
694
695
696 struct lock_class *lock = hlock_class(hlock);
697
698 if (!lock) {
699 printk(KERN_CONT "<RELEASED>\n");
700 return;
701 }
702
703 printk(KERN_CONT "%px", hlock->instance);
704 print_lock_name(lock);
705 printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip);
706}
707
708static void lockdep_print_held_locks(struct task_struct *p)
709{
710 int i, depth = READ_ONCE(p->lockdep_depth);
711
712 if (!depth)
713 printk("no locks held by %s/%d.\n", p->comm, task_pid_nr(p));
714 else
715 printk("%d lock%s held by %s/%d:\n", depth,
716 depth > 1 ? "s" : "", p->comm, task_pid_nr(p));
717
718
719
720
721 if (p->state == TASK_RUNNING && p != current)
722 return;
723 for (i = 0; i < depth; i++) {
724 printk(" #%d: ", i);
725 print_lock(p->held_locks + i);
726 }
727}
728
729static void print_kernel_ident(void)
730{
731 printk("%s %.*s %s\n", init_utsname()->release,
732 (int)strcspn(init_utsname()->version, " "),
733 init_utsname()->version,
734 print_tainted());
735}
736
737static int very_verbose(struct lock_class *class)
738{
739#if VERY_VERBOSE
740 return class_filter(class);
741#endif
742 return 0;
743}
744
745
746
747
748#ifdef __KERNEL__
749static int static_obj(const void *obj)
750{
751 unsigned long start = (unsigned long) &_stext,
752 end = (unsigned long) &_end,
753 addr = (unsigned long) obj;
754
755 if (arch_is_kernel_initmem_freed(addr))
756 return 0;
757
758
759
760
761 if ((addr >= start) && (addr < end))
762 return 1;
763
764 if (arch_is_kernel_data(addr))
765 return 1;
766
767
768
769
770 if (is_kernel_percpu_address(addr))
771 return 1;
772
773
774
775
776 return is_module_address(addr) || is_module_percpu_address(addr);
777}
778#endif
779
780
781
782
783
784
785static int count_matching_names(struct lock_class *new_class)
786{
787 struct lock_class *class;
788 int count = 0;
789
790 if (!new_class->name)
791 return 0;
792
793 list_for_each_entry(class, &all_lock_classes, lock_entry) {
794 if (new_class->key - new_class->subclass == class->key)
795 return class->name_version;
796 if (class->name && !strcmp(class->name, new_class->name))
797 count = max(count, class->name_version);
798 }
799
800 return count + 1;
801}
802
803
804static __always_inline struct lock_class *
805look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
806{
807 struct lockdep_subclass_key *key;
808 struct hlist_head *hash_head;
809 struct lock_class *class;
810
811 if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
812 debug_locks_off();
813 printk(KERN_ERR
814 "BUG: looking up invalid subclass: %u\n", subclass);
815 printk(KERN_ERR
816 "turning off the locking correctness validator.\n");
817 dump_stack();
818 return NULL;
819 }
820
821
822
823
824
825 if (unlikely(!lock->key))
826 return NULL;
827
828
829
830
831
832
833
834 BUILD_BUG_ON(sizeof(struct lock_class_key) >
835 sizeof(struct lockdep_map));
836
837 key = lock->key->subkeys + subclass;
838
839 hash_head = classhashentry(key);
840
841
842
843
844 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
845 return NULL;
846
847 hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
848 if (class->key == key) {
849
850
851
852
853 WARN_ON_ONCE(class->name != lock->name &&
854 lock->key != &__lockdep_no_validate__);
855 return class;
856 }
857 }
858
859 return NULL;
860}
861
862
863
864
865
866
867static bool assign_lock_key(struct lockdep_map *lock)
868{
869 unsigned long can_addr, addr = (unsigned long)lock;
870
871#ifdef __KERNEL__
872
873
874
875
876
877
878
879 BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(raw_spinlock_t));
880#endif
881
882 if (__is_kernel_percpu_address(addr, &can_addr))
883 lock->key = (void *)can_addr;
884 else if (__is_module_percpu_address(addr, &can_addr))
885 lock->key = (void *)can_addr;
886 else if (static_obj(lock))
887 lock->key = (void *)lock;
888 else {
889
890 debug_locks_off();
891 pr_err("INFO: trying to register non-static key.\n");
892 pr_err("the code is fine but needs lockdep annotation.\n");
893 pr_err("turning off the locking correctness validator.\n");
894 dump_stack();
895 return false;
896 }
897
898 return true;
899}
900
901#ifdef CONFIG_DEBUG_LOCKDEP
902
903
904static bool in_list(struct list_head *e, struct list_head *h)
905{
906 struct list_head *f;
907
908 list_for_each(f, h) {
909 if (e == f)
910 return true;
911 }
912
913 return false;
914}
915
916
917
918
919
920static bool in_any_class_list(struct list_head *e)
921{
922 struct lock_class *class;
923 int i;
924
925 for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
926 class = &lock_classes[i];
927 if (in_list(e, &class->locks_after) ||
928 in_list(e, &class->locks_before))
929 return true;
930 }
931 return false;
932}
933
934static bool class_lock_list_valid(struct lock_class *c, struct list_head *h)
935{
936 struct lock_list *e;
937
938 list_for_each_entry(e, h, entry) {
939 if (e->links_to != c) {
940 printk(KERN_INFO "class %s: mismatch for lock entry %ld; class %s <> %s",
941 c->name ? : "(?)",
942 (unsigned long)(e - list_entries),
943 e->links_to && e->links_to->name ?
944 e->links_to->name : "(?)",
945 e->class && e->class->name ? e->class->name :
946 "(?)");
947 return false;
948 }
949 }
950 return true;
951}
952
953#ifdef CONFIG_PROVE_LOCKING
954static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
955#endif
956
957static bool check_lock_chain_key(struct lock_chain *chain)
958{
959#ifdef CONFIG_PROVE_LOCKING
960 u64 chain_key = INITIAL_CHAIN_KEY;
961 int i;
962
963 for (i = chain->base; i < chain->base + chain->depth; i++)
964 chain_key = iterate_chain_key(chain_key, chain_hlocks[i]);
965
966
967
968
969 if (chain->chain_key != chain_key) {
970 printk(KERN_INFO "chain %lld: key %#llx <> %#llx\n",
971 (unsigned long long)(chain - lock_chains),
972 (unsigned long long)chain->chain_key,
973 (unsigned long long)chain_key);
974 return false;
975 }
976#endif
977 return true;
978}
979
980static bool in_any_zapped_class_list(struct lock_class *class)
981{
982 struct pending_free *pf;
983 int i;
984
985 for (i = 0, pf = delayed_free.pf; i < ARRAY_SIZE(delayed_free.pf); i++, pf++) {
986 if (in_list(&class->lock_entry, &pf->zapped))
987 return true;
988 }
989
990 return false;
991}
992
993static bool __check_data_structures(void)
994{
995 struct lock_class *class;
996 struct lock_chain *chain;
997 struct hlist_head *head;
998 struct lock_list *e;
999 int i;
1000
1001
1002 for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
1003 class = &lock_classes[i];
1004 if (!in_list(&class->lock_entry, &all_lock_classes) &&
1005 !in_list(&class->lock_entry, &free_lock_classes) &&
1006 !in_any_zapped_class_list(class)) {
1007 printk(KERN_INFO "class %px/%s is not in any class list\n",
1008 class, class->name ? : "(?)");
1009 return false;
1010 }
1011 }
1012
1013
1014 for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
1015 class = &lock_classes[i];
1016 if (!class_lock_list_valid(class, &class->locks_before))
1017 return false;
1018 if (!class_lock_list_valid(class, &class->locks_after))
1019 return false;
1020 }
1021
1022
1023 for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) {
1024 head = chainhash_table + i;
1025 hlist_for_each_entry_rcu(chain, head, entry) {
1026 if (!check_lock_chain_key(chain))
1027 return false;
1028 }
1029 }
1030
1031
1032
1033
1034
1035 for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) {
1036 e = list_entries + i;
1037 if (!in_any_class_list(&e->entry)) {
1038 printk(KERN_INFO "list entry %d is not in any class list; class %s <> %s\n",
1039 (unsigned int)(e - list_entries),
1040 e->class->name ? : "(?)",
1041 e->links_to->name ? : "(?)");
1042 return false;
1043 }
1044 }
1045
1046
1047
1048
1049
1050 for_each_clear_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) {
1051 e = list_entries + i;
1052 if (in_any_class_list(&e->entry)) {
1053 printk(KERN_INFO "list entry %d occurs in a class list; class %s <> %s\n",
1054 (unsigned int)(e - list_entries),
1055 e->class && e->class->name ? e->class->name :
1056 "(?)",
1057 e->links_to && e->links_to->name ?
1058 e->links_to->name : "(?)");
1059 return false;
1060 }
1061 }
1062
1063 return true;
1064}
1065
1066int check_consistency = 0;
1067module_param(check_consistency, int, 0644);
1068
1069static void check_data_structures(void)
1070{
1071 static bool once = false;
1072
1073 if (check_consistency && !once) {
1074 if (!__check_data_structures()) {
1075 once = true;
1076 WARN_ON(once);
1077 }
1078 }
1079}
1080
1081#else
1082
1083static inline void check_data_structures(void) { }
1084
1085#endif
1086
1087static void init_chain_block_buckets(void);
1088
1089
1090
1091
1092
1093static void init_data_structures_once(void)
1094{
1095 static bool __read_mostly ds_initialized, rcu_head_initialized;
1096 int i;
1097
1098 if (likely(rcu_head_initialized))
1099 return;
1100
1101 if (system_state >= SYSTEM_SCHEDULING) {
1102 init_rcu_head(&delayed_free.rcu_head);
1103 rcu_head_initialized = true;
1104 }
1105
1106 if (ds_initialized)
1107 return;
1108
1109 ds_initialized = true;
1110
1111 INIT_LIST_HEAD(&delayed_free.pf[0].zapped);
1112 INIT_LIST_HEAD(&delayed_free.pf[1].zapped);
1113
1114 for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
1115 list_add_tail(&lock_classes[i].lock_entry, &free_lock_classes);
1116 INIT_LIST_HEAD(&lock_classes[i].locks_after);
1117 INIT_LIST_HEAD(&lock_classes[i].locks_before);
1118 }
1119 init_chain_block_buckets();
1120}
1121
1122static inline struct hlist_head *keyhashentry(const struct lock_class_key *key)
1123{
1124 unsigned long hash = hash_long((uintptr_t)key, KEYHASH_BITS);
1125
1126 return lock_keys_hash + hash;
1127}
1128
1129
1130void lockdep_register_key(struct lock_class_key *key)
1131{
1132 struct hlist_head *hash_head;
1133 struct lock_class_key *k;
1134 unsigned long flags;
1135
1136 if (WARN_ON_ONCE(static_obj(key)))
1137 return;
1138 hash_head = keyhashentry(key);
1139
1140 raw_local_irq_save(flags);
1141 if (!graph_lock())
1142 goto restore_irqs;
1143 hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
1144 if (WARN_ON_ONCE(k == key))
1145 goto out_unlock;
1146 }
1147 hlist_add_head_rcu(&key->hash_entry, hash_head);
1148out_unlock:
1149 graph_unlock();
1150restore_irqs:
1151 raw_local_irq_restore(flags);
1152}
1153EXPORT_SYMBOL_GPL(lockdep_register_key);
1154
1155
1156static bool is_dynamic_key(const struct lock_class_key *key)
1157{
1158 struct hlist_head *hash_head;
1159 struct lock_class_key *k;
1160 bool found = false;
1161
1162 if (WARN_ON_ONCE(static_obj(key)))
1163 return false;
1164
1165
1166
1167
1168
1169
1170 if (!debug_locks)
1171 return true;
1172
1173 hash_head = keyhashentry(key);
1174
1175 rcu_read_lock();
1176 hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
1177 if (k == key) {
1178 found = true;
1179 break;
1180 }
1181 }
1182 rcu_read_unlock();
1183
1184 return found;
1185}
1186
1187
1188
1189
1190
1191
1192static struct lock_class *
1193register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
1194{
1195 struct lockdep_subclass_key *key;
1196 struct hlist_head *hash_head;
1197 struct lock_class *class;
1198
1199 DEBUG_LOCKS_WARN_ON(!irqs_disabled());
1200
1201 class = look_up_lock_class(lock, subclass);
1202 if (likely(class))
1203 goto out_set_class_cache;
1204
1205 if (!lock->key) {
1206 if (!assign_lock_key(lock))
1207 return NULL;
1208 } else if (!static_obj(lock->key) && !is_dynamic_key(lock->key)) {
1209 return NULL;
1210 }
1211
1212 key = lock->key->subkeys + subclass;
1213 hash_head = classhashentry(key);
1214
1215 if (!graph_lock()) {
1216 return NULL;
1217 }
1218
1219
1220
1221
1222 hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
1223 if (class->key == key)
1224 goto out_unlock_set;
1225 }
1226
1227 init_data_structures_once();
1228
1229
1230 class = list_first_entry_or_null(&free_lock_classes, typeof(*class),
1231 lock_entry);
1232 if (!class) {
1233 if (!debug_locks_off_graph_unlock()) {
1234 return NULL;
1235 }
1236
1237 print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
1238 dump_stack();
1239 return NULL;
1240 }
1241 nr_lock_classes++;
1242 __set_bit(class - lock_classes, lock_classes_in_use);
1243 debug_atomic_inc(nr_unused_locks);
1244 class->key = key;
1245 class->name = lock->name;
1246 class->subclass = subclass;
1247 WARN_ON_ONCE(!list_empty(&class->locks_before));
1248 WARN_ON_ONCE(!list_empty(&class->locks_after));
1249 class->name_version = count_matching_names(class);
1250 class->wait_type_inner = lock->wait_type_inner;
1251 class->wait_type_outer = lock->wait_type_outer;
1252
1253
1254
1255
1256 hlist_add_head_rcu(&class->hash_entry, hash_head);
1257
1258
1259
1260
1261 list_move_tail(&class->lock_entry, &all_lock_classes);
1262
1263 if (verbose(class)) {
1264 graph_unlock();
1265
1266 printk("\nnew class %px: %s", class->key, class->name);
1267 if (class->name_version > 1)
1268 printk(KERN_CONT "#%d", class->name_version);
1269 printk(KERN_CONT "\n");
1270 dump_stack();
1271
1272 if (!graph_lock()) {
1273 return NULL;
1274 }
1275 }
1276out_unlock_set:
1277 graph_unlock();
1278
1279out_set_class_cache:
1280 if (!subclass || force)
1281 lock->class_cache[0] = class;
1282 else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
1283 lock->class_cache[subclass] = class;
1284
1285
1286
1287
1288
1289 if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
1290 return NULL;
1291
1292 return class;
1293}
1294
1295#ifdef CONFIG_PROVE_LOCKING
1296
1297
1298
1299
1300static struct lock_list *alloc_list_entry(void)
1301{
1302 int idx = find_first_zero_bit(list_entries_in_use,
1303 ARRAY_SIZE(list_entries));
1304
1305 if (idx >= ARRAY_SIZE(list_entries)) {
1306 if (!debug_locks_off_graph_unlock())
1307 return NULL;
1308
1309 print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
1310 dump_stack();
1311 return NULL;
1312 }
1313 nr_list_entries++;
1314 __set_bit(idx, list_entries_in_use);
1315 return list_entries + idx;
1316}
1317
1318
1319
1320
1321static int add_lock_to_list(struct lock_class *this,
1322 struct lock_class *links_to, struct list_head *head,
1323 unsigned long ip, int distance,
1324 const struct lock_trace *trace)
1325{
1326 struct lock_list *entry;
1327
1328
1329
1330
1331 entry = alloc_list_entry();
1332 if (!entry)
1333 return 0;
1334
1335 entry->class = this;
1336 entry->links_to = links_to;
1337 entry->distance = distance;
1338 entry->trace = trace;
1339
1340
1341
1342
1343
1344 list_add_tail_rcu(&entry->entry, head);
1345
1346 return 1;
1347}
1348
1349
1350
1351
1352#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
1353#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365struct circular_queue {
1366 struct lock_list *element[MAX_CIRCULAR_QUEUE_SIZE];
1367 unsigned int front, rear;
1368};
1369
1370static struct circular_queue lock_cq;
1371
1372unsigned int max_bfs_queue_depth;
1373
1374static unsigned int lockdep_dependency_gen_id;
1375
1376static inline void __cq_init(struct circular_queue *cq)
1377{
1378 cq->front = cq->rear = 0;
1379 lockdep_dependency_gen_id++;
1380}
1381
1382static inline int __cq_empty(struct circular_queue *cq)
1383{
1384 return (cq->front == cq->rear);
1385}
1386
1387static inline int __cq_full(struct circular_queue *cq)
1388{
1389 return ((cq->rear + 1) & CQ_MASK) == cq->front;
1390}
1391
1392static inline int __cq_enqueue(struct circular_queue *cq, struct lock_list *elem)
1393{
1394 if (__cq_full(cq))
1395 return -1;
1396
1397 cq->element[cq->rear] = elem;
1398 cq->rear = (cq->rear + 1) & CQ_MASK;
1399 return 0;
1400}
1401
1402
1403
1404
1405
1406static inline struct lock_list * __cq_dequeue(struct circular_queue *cq)
1407{
1408 struct lock_list * lock;
1409
1410 if (__cq_empty(cq))
1411 return NULL;
1412
1413 lock = cq->element[cq->front];
1414 cq->front = (cq->front + 1) & CQ_MASK;
1415
1416 return lock;
1417}
1418
1419static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
1420{
1421 return (cq->rear - cq->front) & CQ_MASK;
1422}
1423
1424static inline void mark_lock_accessed(struct lock_list *lock,
1425 struct lock_list *parent)
1426{
1427 unsigned long nr;
1428
1429 nr = lock - list_entries;
1430 WARN_ON(nr >= ARRAY_SIZE(list_entries));
1431 lock->parent = parent;
1432 lock->class->dep_gen_id = lockdep_dependency_gen_id;
1433}
1434
1435static inline unsigned long lock_accessed(struct lock_list *lock)
1436{
1437 unsigned long nr;
1438
1439 nr = lock - list_entries;
1440 WARN_ON(nr >= ARRAY_SIZE(list_entries));
1441 return lock->class->dep_gen_id == lockdep_dependency_gen_id;
1442}
1443
1444static inline struct lock_list *get_lock_parent(struct lock_list *child)
1445{
1446 return child->parent;
1447}
1448
1449static inline int get_lock_depth(struct lock_list *child)
1450{
1451 int depth = 0;
1452 struct lock_list *parent;
1453
1454 while ((parent = get_lock_parent(child))) {
1455 child = parent;
1456 depth++;
1457 }
1458 return depth;
1459}
1460
1461
1462
1463
1464
1465
1466
1467
1468static inline struct list_head *get_dep_list(struct lock_list *lock, int offset)
1469{
1470 void *lock_class = lock->class;
1471
1472 return lock_class + offset;
1473}
1474
1475
1476
1477
1478
1479static int __bfs(struct lock_list *source_entry,
1480 void *data,
1481 int (*match)(struct lock_list *entry, void *data),
1482 struct lock_list **target_entry,
1483 int offset)
1484{
1485 struct lock_list *entry;
1486 struct lock_list *lock;
1487 struct list_head *head;
1488 struct circular_queue *cq = &lock_cq;
1489 int ret = 1;
1490
1491 lockdep_assert_locked();
1492
1493 if (match(source_entry, data)) {
1494 *target_entry = source_entry;
1495 ret = 0;
1496 goto exit;
1497 }
1498
1499 head = get_dep_list(source_entry, offset);
1500 if (list_empty(head))
1501 goto exit;
1502
1503 __cq_init(cq);
1504 __cq_enqueue(cq, source_entry);
1505
1506 while ((lock = __cq_dequeue(cq))) {
1507
1508 if (!lock->class) {
1509 ret = -2;
1510 goto exit;
1511 }
1512
1513 head = get_dep_list(lock, offset);
1514
1515 list_for_each_entry_rcu(entry, head, entry) {
1516 if (!lock_accessed(entry)) {
1517 unsigned int cq_depth;
1518 mark_lock_accessed(entry, lock);
1519 if (match(entry, data)) {
1520 *target_entry = entry;
1521 ret = 0;
1522 goto exit;
1523 }
1524
1525 if (__cq_enqueue(cq, entry)) {
1526 ret = -1;
1527 goto exit;
1528 }
1529 cq_depth = __cq_get_elem_count(cq);
1530 if (max_bfs_queue_depth < cq_depth)
1531 max_bfs_queue_depth = cq_depth;
1532 }
1533 }
1534 }
1535exit:
1536 return ret;
1537}
1538
1539static inline int __bfs_forwards(struct lock_list *src_entry,
1540 void *data,
1541 int (*match)(struct lock_list *entry, void *data),
1542 struct lock_list **target_entry)
1543{
1544 return __bfs(src_entry, data, match, target_entry,
1545 offsetof(struct lock_class, locks_after));
1546
1547}
1548
1549static inline int __bfs_backwards(struct lock_list *src_entry,
1550 void *data,
1551 int (*match)(struct lock_list *entry, void *data),
1552 struct lock_list **target_entry)
1553{
1554 return __bfs(src_entry, data, match, target_entry,
1555 offsetof(struct lock_class, locks_before));
1556
1557}
1558
1559static void print_lock_trace(const struct lock_trace *trace,
1560 unsigned int spaces)
1561{
1562 stack_trace_print(trace->entries, trace->nr_entries, spaces);
1563}
1564
1565
1566
1567
1568
1569static noinline void
1570print_circular_bug_entry(struct lock_list *target, int depth)
1571{
1572 if (debug_locks_silent)
1573 return;
1574 printk("\n-> #%u", depth);
1575 print_lock_name(target->class);
1576 printk(KERN_CONT ":\n");
1577 print_lock_trace(target->trace, 6);
1578}
1579
1580static void
1581print_circular_lock_scenario(struct held_lock *src,
1582 struct held_lock *tgt,
1583 struct lock_list *prt)
1584{
1585 struct lock_class *source = hlock_class(src);
1586 struct lock_class *target = hlock_class(tgt);
1587 struct lock_class *parent = prt->class;
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602 if (parent != source) {
1603 printk("Chain exists of:\n ");
1604 __print_lock_name(source);
1605 printk(KERN_CONT " --> ");
1606 __print_lock_name(parent);
1607 printk(KERN_CONT " --> ");
1608 __print_lock_name(target);
1609 printk(KERN_CONT "\n\n");
1610 }
1611
1612 printk(" Possible unsafe locking scenario:\n\n");
1613 printk(" CPU0 CPU1\n");
1614 printk(" ---- ----\n");
1615 printk(" lock(");
1616 __print_lock_name(target);
1617 printk(KERN_CONT ");\n");
1618 printk(" lock(");
1619 __print_lock_name(parent);
1620 printk(KERN_CONT ");\n");
1621 printk(" lock(");
1622 __print_lock_name(target);
1623 printk(KERN_CONT ");\n");
1624 printk(" lock(");
1625 __print_lock_name(source);
1626 printk(KERN_CONT ");\n");
1627 printk("\n *** DEADLOCK ***\n\n");
1628}
1629
1630
1631
1632
1633
1634static noinline void
1635print_circular_bug_header(struct lock_list *entry, unsigned int depth,
1636 struct held_lock *check_src,
1637 struct held_lock *check_tgt)
1638{
1639 struct task_struct *curr = current;
1640
1641 if (debug_locks_silent)
1642 return;
1643
1644 pr_warn("\n");
1645 pr_warn("======================================================\n");
1646 pr_warn("WARNING: possible circular locking dependency detected\n");
1647 print_kernel_ident();
1648 pr_warn("------------------------------------------------------\n");
1649 pr_warn("%s/%d is trying to acquire lock:\n",
1650 curr->comm, task_pid_nr(curr));
1651 print_lock(check_src);
1652
1653 pr_warn("\nbut task is already holding lock:\n");
1654
1655 print_lock(check_tgt);
1656 pr_warn("\nwhich lock already depends on the new lock.\n\n");
1657 pr_warn("\nthe existing dependency chain (in reverse order) is:\n");
1658
1659 print_circular_bug_entry(entry, depth);
1660}
1661
1662static inline int class_equal(struct lock_list *entry, void *data)
1663{
1664 return entry->class == data;
1665}
1666
1667static noinline void print_circular_bug(struct lock_list *this,
1668 struct lock_list *target,
1669 struct held_lock *check_src,
1670 struct held_lock *check_tgt)
1671{
1672 struct task_struct *curr = current;
1673 struct lock_list *parent;
1674 struct lock_list *first_parent;
1675 int depth;
1676
1677 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1678 return;
1679
1680 this->trace = save_trace();
1681 if (!this->trace)
1682 return;
1683
1684 depth = get_lock_depth(target);
1685
1686 print_circular_bug_header(target, depth, check_src, check_tgt);
1687
1688 parent = get_lock_parent(target);
1689 first_parent = parent;
1690
1691 while (parent) {
1692 print_circular_bug_entry(parent, --depth);
1693 parent = get_lock_parent(parent);
1694 }
1695
1696 printk("\nother info that might help us debug this:\n\n");
1697 print_circular_lock_scenario(check_src, check_tgt,
1698 first_parent);
1699
1700 lockdep_print_held_locks(curr);
1701
1702 printk("\nstack backtrace:\n");
1703 dump_stack();
1704}
1705
1706static noinline void print_bfs_bug(int ret)
1707{
1708 if (!debug_locks_off_graph_unlock())
1709 return;
1710
1711
1712
1713
1714 WARN(1, "lockdep bfs error:%d\n", ret);
1715}
1716
1717static int noop_count(struct lock_list *entry, void *data)
1718{
1719 (*(unsigned long *)data)++;
1720 return 0;
1721}
1722
1723static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
1724{
1725 unsigned long count = 0;
1726 struct lock_list *target_entry;
1727
1728 __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
1729
1730 return count;
1731}
1732unsigned long lockdep_count_forward_deps(struct lock_class *class)
1733{
1734 unsigned long ret, flags;
1735 struct lock_list this;
1736
1737 this.parent = NULL;
1738 this.class = class;
1739
1740 raw_local_irq_save(flags);
1741 lockdep_lock();
1742 ret = __lockdep_count_forward_deps(&this);
1743 lockdep_unlock();
1744 raw_local_irq_restore(flags);
1745
1746 return ret;
1747}
1748
1749static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
1750{
1751 unsigned long count = 0;
1752 struct lock_list *target_entry;
1753
1754 __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
1755
1756 return count;
1757}
1758
1759unsigned long lockdep_count_backward_deps(struct lock_class *class)
1760{
1761 unsigned long ret, flags;
1762 struct lock_list this;
1763
1764 this.parent = NULL;
1765 this.class = class;
1766
1767 raw_local_irq_save(flags);
1768 lockdep_lock();
1769 ret = __lockdep_count_backward_deps(&this);
1770 lockdep_unlock();
1771 raw_local_irq_restore(flags);
1772
1773 return ret;
1774}
1775
1776
1777
1778
1779
1780static noinline int
1781check_path(struct lock_class *target, struct lock_list *src_entry,
1782 struct lock_list **target_entry)
1783{
1784 int ret;
1785
1786 ret = __bfs_forwards(src_entry, (void *)target, class_equal,
1787 target_entry);
1788
1789 if (unlikely(ret < 0))
1790 print_bfs_bug(ret);
1791
1792 return ret;
1793}
1794
1795
1796
1797
1798
1799
1800
1801
1802static noinline int
1803check_noncircular(struct held_lock *src, struct held_lock *target,
1804 struct lock_trace **const trace)
1805{
1806 int ret;
1807 struct lock_list *target_entry;
1808 struct lock_list src_entry = {
1809 .class = hlock_class(src),
1810 .parent = NULL,
1811 };
1812
1813 debug_atomic_inc(nr_cyclic_checks);
1814
1815 ret = check_path(hlock_class(target), &src_entry, &target_entry);
1816
1817 if (unlikely(!ret)) {
1818 if (!*trace) {
1819
1820
1821
1822
1823
1824 *trace = save_trace();
1825 }
1826
1827 print_circular_bug(&src_entry, target_entry, src, target);
1828 }
1829
1830 return ret;
1831}
1832
1833#ifdef CONFIG_LOCKDEP_SMALL
1834
1835
1836
1837
1838
1839
1840
1841static noinline int
1842check_redundant(struct held_lock *src, struct held_lock *target)
1843{
1844 int ret;
1845 struct lock_list *target_entry;
1846 struct lock_list src_entry = {
1847 .class = hlock_class(src),
1848 .parent = NULL,
1849 };
1850
1851 debug_atomic_inc(nr_redundant_checks);
1852
1853 ret = check_path(hlock_class(target), &src_entry, &target_entry);
1854
1855 if (!ret) {
1856 debug_atomic_inc(nr_redundant);
1857 ret = 2;
1858 } else if (ret < 0)
1859 ret = 0;
1860
1861 return ret;
1862}
1863#endif
1864
1865#ifdef CONFIG_TRACE_IRQFLAGS
1866
1867static inline int usage_accumulate(struct lock_list *entry, void *mask)
1868{
1869 *(unsigned long *)mask |= entry->class->usage_mask;
1870
1871 return 0;
1872}
1873
1874
1875
1876
1877
1878
1879
1880static inline int usage_match(struct lock_list *entry, void *mask)
1881{
1882 return entry->class->usage_mask & *(unsigned long *)mask;
1883}
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895static int
1896find_usage_forwards(struct lock_list *root, unsigned long usage_mask,
1897 struct lock_list **target_entry)
1898{
1899 int result;
1900
1901 debug_atomic_inc(nr_find_usage_forwards_checks);
1902
1903 result = __bfs_forwards(root, &usage_mask, usage_match, target_entry);
1904
1905 return result;
1906}
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918static int
1919find_usage_backwards(struct lock_list *root, unsigned long usage_mask,
1920 struct lock_list **target_entry)
1921{
1922 int result;
1923
1924 debug_atomic_inc(nr_find_usage_backwards_checks);
1925
1926 result = __bfs_backwards(root, &usage_mask, usage_match, target_entry);
1927
1928 return result;
1929}
1930
1931static void print_lock_class_header(struct lock_class *class, int depth)
1932{
1933 int bit;
1934
1935 printk("%*s->", depth, "");
1936 print_lock_name(class);
1937#ifdef CONFIG_DEBUG_LOCKDEP
1938 printk(KERN_CONT " ops: %lu", debug_class_ops_read(class));
1939#endif
1940 printk(KERN_CONT " {\n");
1941
1942 for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
1943 if (class->usage_mask & (1 << bit)) {
1944 int len = depth;
1945
1946 len += printk("%*s %s", depth, "", usage_str[bit]);
1947 len += printk(KERN_CONT " at:\n");
1948 print_lock_trace(class->usage_traces[bit], len);
1949 }
1950 }
1951 printk("%*s }\n", depth, "");
1952
1953 printk("%*s ... key at: [<%px>] %pS\n",
1954 depth, "", class->key, class->key);
1955}
1956
1957
1958
1959
1960static void __used
1961print_shortest_lock_dependencies(struct lock_list *leaf,
1962 struct lock_list *root)
1963{
1964 struct lock_list *entry = leaf;
1965 int depth;
1966
1967
1968 depth = get_lock_depth(leaf);
1969
1970 do {
1971 print_lock_class_header(entry->class, depth);
1972 printk("%*s ... acquired at:\n", depth, "");
1973 print_lock_trace(entry->trace, 2);
1974 printk("\n");
1975
1976 if (depth == 0 && (entry != root)) {
1977 printk("lockdep:%s bad path found in chain graph\n", __func__);
1978 break;
1979 }
1980
1981 entry = get_lock_parent(entry);
1982 depth--;
1983 } while (entry && (depth >= 0));
1984}
1985
1986static void
1987print_irq_lock_scenario(struct lock_list *safe_entry,
1988 struct lock_list *unsafe_entry,
1989 struct lock_class *prev_class,
1990 struct lock_class *next_class)
1991{
1992 struct lock_class *safe_class = safe_entry->class;
1993 struct lock_class *unsafe_class = unsafe_entry->class;
1994 struct lock_class *middle_class = prev_class;
1995
1996 if (middle_class == safe_class)
1997 middle_class = next_class;
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012 if (middle_class != unsafe_class) {
2013 printk("Chain exists of:\n ");
2014 __print_lock_name(safe_class);
2015 printk(KERN_CONT " --> ");
2016 __print_lock_name(middle_class);
2017 printk(KERN_CONT " --> ");
2018 __print_lock_name(unsafe_class);
2019 printk(KERN_CONT "\n\n");
2020 }
2021
2022 printk(" Possible interrupt unsafe locking scenario:\n\n");
2023 printk(" CPU0 CPU1\n");
2024 printk(" ---- ----\n");
2025 printk(" lock(");
2026 __print_lock_name(unsafe_class);
2027 printk(KERN_CONT ");\n");
2028 printk(" local_irq_disable();\n");
2029 printk(" lock(");
2030 __print_lock_name(safe_class);
2031 printk(KERN_CONT ");\n");
2032 printk(" lock(");
2033 __print_lock_name(middle_class);
2034 printk(KERN_CONT ");\n");
2035 printk(" <Interrupt>\n");
2036 printk(" lock(");
2037 __print_lock_name(safe_class);
2038 printk(KERN_CONT ");\n");
2039 printk("\n *** DEADLOCK ***\n\n");
2040}
2041
2042static void
2043print_bad_irq_dependency(struct task_struct *curr,
2044 struct lock_list *prev_root,
2045 struct lock_list *next_root,
2046 struct lock_list *backwards_entry,
2047 struct lock_list *forwards_entry,
2048 struct held_lock *prev,
2049 struct held_lock *next,
2050 enum lock_usage_bit bit1,
2051 enum lock_usage_bit bit2,
2052 const char *irqclass)
2053{
2054 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2055 return;
2056
2057 pr_warn("\n");
2058 pr_warn("=====================================================\n");
2059 pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n",
2060 irqclass, irqclass);
2061 print_kernel_ident();
2062 pr_warn("-----------------------------------------------------\n");
2063 pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
2064 curr->comm, task_pid_nr(curr),
2065 lockdep_hardirq_context(), hardirq_count() >> HARDIRQ_SHIFT,
2066 curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
2067 lockdep_hardirqs_enabled(),
2068 curr->softirqs_enabled);
2069 print_lock(next);
2070
2071 pr_warn("\nand this task is already holding:\n");
2072 print_lock(prev);
2073 pr_warn("which would create a new lock dependency:\n");
2074 print_lock_name(hlock_class(prev));
2075 pr_cont(" ->");
2076 print_lock_name(hlock_class(next));
2077 pr_cont("\n");
2078
2079 pr_warn("\nbut this new dependency connects a %s-irq-safe lock:\n",
2080 irqclass);
2081 print_lock_name(backwards_entry->class);
2082 pr_warn("\n... which became %s-irq-safe at:\n", irqclass);
2083
2084 print_lock_trace(backwards_entry->class->usage_traces[bit1], 1);
2085
2086 pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass);
2087 print_lock_name(forwards_entry->class);
2088 pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass);
2089 pr_warn("...");
2090
2091 print_lock_trace(forwards_entry->class->usage_traces[bit2], 1);
2092
2093 pr_warn("\nother info that might help us debug this:\n\n");
2094 print_irq_lock_scenario(backwards_entry, forwards_entry,
2095 hlock_class(prev), hlock_class(next));
2096
2097 lockdep_print_held_locks(curr);
2098
2099 pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass);
2100 prev_root->trace = save_trace();
2101 if (!prev_root->trace)
2102 return;
2103 print_shortest_lock_dependencies(backwards_entry, prev_root);
2104
2105 pr_warn("\nthe dependencies between the lock to be acquired");
2106 pr_warn(" and %s-irq-unsafe lock:\n", irqclass);
2107 next_root->trace = save_trace();
2108 if (!next_root->trace)
2109 return;
2110 print_shortest_lock_dependencies(forwards_entry, next_root);
2111
2112 pr_warn("\nstack backtrace:\n");
2113 dump_stack();
2114}
2115
2116static const char *state_names[] = {
2117#define LOCKDEP_STATE(__STATE) \
2118 __stringify(__STATE),
2119#include "lockdep_states.h"
2120#undef LOCKDEP_STATE
2121};
2122
2123static const char *state_rnames[] = {
2124#define LOCKDEP_STATE(__STATE) \
2125 __stringify(__STATE)"-READ",
2126#include "lockdep_states.h"
2127#undef LOCKDEP_STATE
2128};
2129
2130static inline const char *state_name(enum lock_usage_bit bit)
2131{
2132 if (bit & LOCK_USAGE_READ_MASK)
2133 return state_rnames[bit >> LOCK_USAGE_DIR_MASK];
2134 else
2135 return state_names[bit >> LOCK_USAGE_DIR_MASK];
2136}
2137
2138
2139
2140
2141
2142
2143
2144
2145static int exclusive_bit(int new_bit)
2146{
2147 int state = new_bit & LOCK_USAGE_STATE_MASK;
2148 int dir = new_bit & LOCK_USAGE_DIR_MASK;
2149
2150
2151
2152
2153 return state | (dir ^ LOCK_USAGE_DIR_MASK);
2154}
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170static unsigned long invert_dir_mask(unsigned long mask)
2171{
2172 unsigned long excl = 0;
2173
2174
2175 excl |= (mask & LOCKF_ENABLED_IRQ_ALL) >> LOCK_USAGE_DIR_MASK;
2176 excl |= (mask & LOCKF_USED_IN_IRQ_ALL) << LOCK_USAGE_DIR_MASK;
2177
2178 return excl;
2179}
2180
2181
2182
2183
2184
2185
2186static unsigned long exclusive_mask(unsigned long mask)
2187{
2188 unsigned long excl = invert_dir_mask(mask);
2189
2190
2191 excl |= (excl & LOCKF_IRQ_READ) >> LOCK_USAGE_READ_MASK;
2192 excl &= ~LOCKF_IRQ_READ;
2193
2194 return excl;
2195}
2196
2197
2198
2199
2200
2201
2202
2203
2204static unsigned long original_mask(unsigned long mask)
2205{
2206 unsigned long excl = invert_dir_mask(mask);
2207
2208
2209 excl |= (excl & LOCKF_IRQ) << LOCK_USAGE_READ_MASK;
2210
2211 return excl;
2212}
2213
2214
2215
2216
2217
2218static int find_exclusive_match(unsigned long mask,
2219 unsigned long excl_mask,
2220 enum lock_usage_bit *bitp,
2221 enum lock_usage_bit *excl_bitp)
2222{
2223 int bit, excl;
2224
2225 for_each_set_bit(bit, &mask, LOCK_USED) {
2226 excl = exclusive_bit(bit);
2227 if (excl_mask & lock_flag(excl)) {
2228 *bitp = bit;
2229 *excl_bitp = excl;
2230 return 0;
2231 }
2232 }
2233 return -1;
2234}
2235
2236
2237
2238
2239
2240
2241
2242static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
2243 struct held_lock *next)
2244{
2245 unsigned long usage_mask = 0, forward_mask, backward_mask;
2246 enum lock_usage_bit forward_bit = 0, backward_bit = 0;
2247 struct lock_list *target_entry1;
2248 struct lock_list *target_entry;
2249 struct lock_list this, that;
2250 int ret;
2251
2252
2253
2254
2255
2256 this.parent = NULL;
2257 this.class = hlock_class(prev);
2258
2259 ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL);
2260 if (ret < 0) {
2261 print_bfs_bug(ret);
2262 return 0;
2263 }
2264
2265 usage_mask &= LOCKF_USED_IN_IRQ_ALL;
2266 if (!usage_mask)
2267 return 1;
2268
2269
2270
2271
2272
2273 forward_mask = exclusive_mask(usage_mask);
2274
2275 that.parent = NULL;
2276 that.class = hlock_class(next);
2277
2278 ret = find_usage_forwards(&that, forward_mask, &target_entry1);
2279 if (ret < 0) {
2280 print_bfs_bug(ret);
2281 return 0;
2282 }
2283 if (ret == 1)
2284 return ret;
2285
2286
2287
2288
2289
2290
2291 backward_mask = original_mask(target_entry1->class->usage_mask);
2292
2293 ret = find_usage_backwards(&this, backward_mask, &target_entry);
2294 if (ret < 0) {
2295 print_bfs_bug(ret);
2296 return 0;
2297 }
2298 if (DEBUG_LOCKS_WARN_ON(ret == 1))
2299 return 1;
2300
2301
2302
2303
2304
2305 ret = find_exclusive_match(target_entry->class->usage_mask,
2306 target_entry1->class->usage_mask,
2307 &backward_bit, &forward_bit);
2308 if (DEBUG_LOCKS_WARN_ON(ret == -1))
2309 return 1;
2310
2311 print_bad_irq_dependency(curr, &this, &that,
2312 target_entry, target_entry1,
2313 prev, next,
2314 backward_bit, forward_bit,
2315 state_name(backward_bit));
2316
2317 return 0;
2318}
2319
2320#else
2321
2322static inline int check_irq_usage(struct task_struct *curr,
2323 struct held_lock *prev, struct held_lock *next)
2324{
2325 return 1;
2326}
2327#endif
2328
2329static void inc_chains(int irq_context)
2330{
2331 if (irq_context & LOCK_CHAIN_HARDIRQ_CONTEXT)
2332 nr_hardirq_chains++;
2333 else if (irq_context & LOCK_CHAIN_SOFTIRQ_CONTEXT)
2334 nr_softirq_chains++;
2335 else
2336 nr_process_chains++;
2337}
2338
2339static void dec_chains(int irq_context)
2340{
2341 if (irq_context & LOCK_CHAIN_HARDIRQ_CONTEXT)
2342 nr_hardirq_chains--;
2343 else if (irq_context & LOCK_CHAIN_SOFTIRQ_CONTEXT)
2344 nr_softirq_chains--;
2345 else
2346 nr_process_chains--;
2347}
2348
2349static void
2350print_deadlock_scenario(struct held_lock *nxt, struct held_lock *prv)
2351{
2352 struct lock_class *next = hlock_class(nxt);
2353 struct lock_class *prev = hlock_class(prv);
2354
2355 printk(" Possible unsafe locking scenario:\n\n");
2356 printk(" CPU0\n");
2357 printk(" ----\n");
2358 printk(" lock(");
2359 __print_lock_name(prev);
2360 printk(KERN_CONT ");\n");
2361 printk(" lock(");
2362 __print_lock_name(next);
2363 printk(KERN_CONT ");\n");
2364 printk("\n *** DEADLOCK ***\n\n");
2365 printk(" May be due to missing lock nesting notation\n\n");
2366}
2367
2368static void
2369print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
2370 struct held_lock *next)
2371{
2372 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2373 return;
2374
2375 pr_warn("\n");
2376 pr_warn("============================================\n");
2377 pr_warn("WARNING: possible recursive locking detected\n");
2378 print_kernel_ident();
2379 pr_warn("--------------------------------------------\n");
2380 pr_warn("%s/%d is trying to acquire lock:\n",
2381 curr->comm, task_pid_nr(curr));
2382 print_lock(next);
2383 pr_warn("\nbut task is already holding lock:\n");
2384 print_lock(prev);
2385
2386 pr_warn("\nother info that might help us debug this:\n");
2387 print_deadlock_scenario(next, prev);
2388 lockdep_print_held_locks(curr);
2389
2390 pr_warn("\nstack backtrace:\n");
2391 dump_stack();
2392}
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402static int
2403check_deadlock(struct task_struct *curr, struct held_lock *next)
2404{
2405 struct held_lock *prev;
2406 struct held_lock *nest = NULL;
2407 int i;
2408
2409 for (i = 0; i < curr->lockdep_depth; i++) {
2410 prev = curr->held_locks + i;
2411
2412 if (prev->instance == next->nest_lock)
2413 nest = prev;
2414
2415 if (hlock_class(prev) != hlock_class(next))
2416 continue;
2417
2418
2419
2420
2421
2422 if ((next->read == 2) && prev->read)
2423 return 2;
2424
2425
2426
2427
2428
2429 if (nest)
2430 return 2;
2431
2432 print_deadlock_bug(curr, prev, next);
2433 return 0;
2434 }
2435 return 1;
2436}
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460static int
2461check_prev_add(struct task_struct *curr, struct held_lock *prev,
2462 struct held_lock *next, int distance,
2463 struct lock_trace **const trace)
2464{
2465 struct lock_list *entry;
2466 int ret;
2467
2468 if (!hlock_class(prev)->key || !hlock_class(next)->key) {
2469
2470
2471
2472
2473
2474
2475 WARN_ONCE(!debug_locks_silent && !hlock_class(prev)->key,
2476 "Detected use-after-free of lock class %px/%s\n",
2477 hlock_class(prev),
2478 hlock_class(prev)->name);
2479 WARN_ONCE(!debug_locks_silent && !hlock_class(next)->key,
2480 "Detected use-after-free of lock class %px/%s\n",
2481 hlock_class(next),
2482 hlock_class(next)->name);
2483 return 2;
2484 }
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496 ret = check_noncircular(next, prev, trace);
2497 if (unlikely(ret <= 0))
2498 return 0;
2499
2500 if (!check_irq_usage(curr, prev, next))
2501 return 0;
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511 if (next->read == 2 || prev->read == 2)
2512 return 1;
2513
2514
2515
2516
2517
2518
2519
2520
2521 list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
2522 if (entry->class == hlock_class(next)) {
2523 if (distance == 1)
2524 entry->distance = 1;
2525 return 1;
2526 }
2527 }
2528
2529#ifdef CONFIG_LOCKDEP_SMALL
2530
2531
2532
2533 ret = check_redundant(prev, next);
2534 if (ret != 1)
2535 return ret;
2536#endif
2537
2538 if (!*trace) {
2539 *trace = save_trace();
2540 if (!*trace)
2541 return 0;
2542 }
2543
2544
2545
2546
2547
2548 ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
2549 &hlock_class(prev)->locks_after,
2550 next->acquire_ip, distance, *trace);
2551
2552 if (!ret)
2553 return 0;
2554
2555 ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
2556 &hlock_class(next)->locks_before,
2557 next->acquire_ip, distance, *trace);
2558 if (!ret)
2559 return 0;
2560
2561 return 2;
2562}
2563
2564
2565
2566
2567
2568
2569
2570static int
2571check_prevs_add(struct task_struct *curr, struct held_lock *next)
2572{
2573 struct lock_trace *trace = NULL;
2574 int depth = curr->lockdep_depth;
2575 struct held_lock *hlock;
2576
2577
2578
2579
2580
2581
2582 if (!depth)
2583 goto out_bug;
2584
2585
2586
2587
2588 if (curr->held_locks[depth].irq_context !=
2589 curr->held_locks[depth-1].irq_context)
2590 goto out_bug;
2591
2592 for (;;) {
2593 int distance = curr->lockdep_depth - depth + 1;
2594 hlock = curr->held_locks + depth - 1;
2595
2596
2597
2598
2599
2600 if (hlock->read != 2 && hlock->check) {
2601 int ret = check_prev_add(curr, hlock, next, distance,
2602 &trace);
2603 if (!ret)
2604 return 0;
2605
2606
2607
2608
2609
2610
2611
2612 if (!hlock->trylock)
2613 break;
2614 }
2615
2616 depth--;
2617
2618
2619
2620 if (!depth)
2621 break;
2622
2623
2624
2625 if (curr->held_locks[depth].irq_context !=
2626 curr->held_locks[depth-1].irq_context)
2627 break;
2628 }
2629 return 1;
2630out_bug:
2631 if (!debug_locks_off_graph_unlock())
2632 return 0;
2633
2634
2635
2636
2637
2638
2639 WARN_ON(1);
2640
2641 return 0;
2642}
2643
2644struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
2645static DECLARE_BITMAP(lock_chains_in_use, MAX_LOCKDEP_CHAINS);
2646static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
2647unsigned long nr_zapped_lock_chains;
2648unsigned int nr_free_chain_hlocks;
2649unsigned int nr_lost_chain_hlocks;
2650unsigned int nr_large_chain_blocks;
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669#define MAX_CHAIN_BUCKETS 16
2670#define CHAIN_BLK_FLAG (1U << 15)
2671#define CHAIN_BLK_LIST_END 0xFFFFU
2672
2673static int chain_block_buckets[MAX_CHAIN_BUCKETS];
2674
2675static inline int size_to_bucket(int size)
2676{
2677 if (size > MAX_CHAIN_BUCKETS)
2678 return 0;
2679
2680 return size - 1;
2681}
2682
2683
2684
2685
2686#define for_each_chain_block(bucket, prev, curr) \
2687 for ((prev) = -1, (curr) = chain_block_buckets[bucket]; \
2688 (curr) >= 0; \
2689 (prev) = (curr), (curr) = chain_block_next(curr))
2690
2691
2692
2693
2694static inline int chain_block_next(int offset)
2695{
2696 int next = chain_hlocks[offset];
2697
2698 WARN_ON_ONCE(!(next & CHAIN_BLK_FLAG));
2699
2700 if (next == CHAIN_BLK_LIST_END)
2701 return -1;
2702
2703 next &= ~CHAIN_BLK_FLAG;
2704 next <<= 16;
2705 next |= chain_hlocks[offset + 1];
2706
2707 return next;
2708}
2709
2710
2711
2712
2713static inline int chain_block_size(int offset)
2714{
2715 return (chain_hlocks[offset + 2] << 16) | chain_hlocks[offset + 3];
2716}
2717
2718static inline void init_chain_block(int offset, int next, int bucket, int size)
2719{
2720 chain_hlocks[offset] = (next >> 16) | CHAIN_BLK_FLAG;
2721 chain_hlocks[offset + 1] = (u16)next;
2722
2723 if (size && !bucket) {
2724 chain_hlocks[offset + 2] = size >> 16;
2725 chain_hlocks[offset + 3] = (u16)size;
2726 }
2727}
2728
2729static inline void add_chain_block(int offset, int size)
2730{
2731 int bucket = size_to_bucket(size);
2732 int next = chain_block_buckets[bucket];
2733 int prev, curr;
2734
2735 if (unlikely(size < 2)) {
2736
2737
2738
2739
2740
2741
2742
2743 if (size)
2744 nr_lost_chain_hlocks++;
2745 return;
2746 }
2747
2748 nr_free_chain_hlocks += size;
2749 if (!bucket) {
2750 nr_large_chain_blocks++;
2751
2752
2753
2754
2755 for_each_chain_block(0, prev, curr) {
2756 if (size >= chain_block_size(curr))
2757 break;
2758 }
2759 init_chain_block(offset, curr, 0, size);
2760 if (prev < 0)
2761 chain_block_buckets[0] = offset;
2762 else
2763 init_chain_block(prev, offset, 0, 0);
2764 return;
2765 }
2766
2767
2768
2769 init_chain_block(offset, next, bucket, size);
2770 chain_block_buckets[bucket] = offset;
2771}
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784static inline void del_chain_block(int bucket, int size, int next)
2785{
2786 nr_free_chain_hlocks -= size;
2787 chain_block_buckets[bucket] = next;
2788
2789 if (!bucket)
2790 nr_large_chain_blocks--;
2791}
2792
2793static void init_chain_block_buckets(void)
2794{
2795 int i;
2796
2797 for (i = 0; i < MAX_CHAIN_BUCKETS; i++)
2798 chain_block_buckets[i] = -1;
2799
2800 add_chain_block(0, ARRAY_SIZE(chain_hlocks));
2801}
2802
2803
2804
2805
2806
2807
2808
2809static int alloc_chain_hlocks(int req)
2810{
2811 int bucket, curr, size;
2812
2813
2814
2815
2816
2817 BUILD_BUG_ON((MAX_LOCKDEP_KEYS-1) & CHAIN_BLK_FLAG);
2818
2819 init_data_structures_once();
2820
2821 if (nr_free_chain_hlocks < req)
2822 return -1;
2823
2824
2825
2826
2827
2828 req = max(req, 2);
2829 bucket = size_to_bucket(req);
2830 curr = chain_block_buckets[bucket];
2831
2832 if (bucket) {
2833 if (curr >= 0) {
2834 del_chain_block(bucket, req, chain_block_next(curr));
2835 return curr;
2836 }
2837
2838 curr = chain_block_buckets[0];
2839 }
2840
2841
2842
2843
2844
2845 if (curr >= 0) {
2846 size = chain_block_size(curr);
2847 if (likely(size >= req)) {
2848 del_chain_block(0, size, chain_block_next(curr));
2849 add_chain_block(curr + req, size - req);
2850 return curr;
2851 }
2852 }
2853
2854
2855
2856
2857 for (size = MAX_CHAIN_BUCKETS; size > req; size--) {
2858 bucket = size_to_bucket(size);
2859 curr = chain_block_buckets[bucket];
2860 if (curr < 0)
2861 continue;
2862
2863 del_chain_block(bucket, size, chain_block_next(curr));
2864 add_chain_block(curr + req, size - req);
2865 return curr;
2866 }
2867
2868 return -1;
2869}
2870
2871static inline void free_chain_hlocks(int base, int size)
2872{
2873 add_chain_block(base, max(size, 2));
2874}
2875
2876struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
2877{
2878 return lock_classes + chain_hlocks[chain->base + i];
2879}
2880
2881
2882
2883
2884static inline int get_first_held_lock(struct task_struct *curr,
2885 struct held_lock *hlock)
2886{
2887 int i;
2888 struct held_lock *hlock_curr;
2889
2890 for (i = curr->lockdep_depth - 1; i >= 0; i--) {
2891 hlock_curr = curr->held_locks + i;
2892 if (hlock_curr->irq_context != hlock->irq_context)
2893 break;
2894
2895 }
2896
2897 return ++i;
2898}
2899
2900#ifdef CONFIG_DEBUG_LOCKDEP
2901
2902
2903
2904static u64 print_chain_key_iteration(int class_idx, u64 chain_key)
2905{
2906 u64 new_chain_key = iterate_chain_key(chain_key, class_idx);
2907
2908 printk(" class_idx:%d -> chain_key:%016Lx",
2909 class_idx,
2910 (unsigned long long)new_chain_key);
2911 return new_chain_key;
2912}
2913
2914static void
2915print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
2916{
2917 struct held_lock *hlock;
2918 u64 chain_key = INITIAL_CHAIN_KEY;
2919 int depth = curr->lockdep_depth;
2920 int i = get_first_held_lock(curr, hlock_next);
2921
2922 printk("depth: %u (irq_context %u)\n", depth - i + 1,
2923 hlock_next->irq_context);
2924 for (; i < depth; i++) {
2925 hlock = curr->held_locks + i;
2926 chain_key = print_chain_key_iteration(hlock->class_idx, chain_key);
2927
2928 print_lock(hlock);
2929 }
2930
2931 print_chain_key_iteration(hlock_next->class_idx, chain_key);
2932 print_lock(hlock_next);
2933}
2934
2935static void print_chain_keys_chain(struct lock_chain *chain)
2936{
2937 int i;
2938 u64 chain_key = INITIAL_CHAIN_KEY;
2939 int class_id;
2940
2941 printk("depth: %u\n", chain->depth);
2942 for (i = 0; i < chain->depth; i++) {
2943 class_id = chain_hlocks[chain->base + i];
2944 chain_key = print_chain_key_iteration(class_id, chain_key);
2945
2946 print_lock_name(lock_classes + class_id);
2947 printk("\n");
2948 }
2949}
2950
2951static void print_collision(struct task_struct *curr,
2952 struct held_lock *hlock_next,
2953 struct lock_chain *chain)
2954{
2955 pr_warn("\n");
2956 pr_warn("============================\n");
2957 pr_warn("WARNING: chain_key collision\n");
2958 print_kernel_ident();
2959 pr_warn("----------------------------\n");
2960 pr_warn("%s/%d: ", current->comm, task_pid_nr(current));
2961 pr_warn("Hash chain already cached but the contents don't match!\n");
2962
2963 pr_warn("Held locks:");
2964 print_chain_keys_held_locks(curr, hlock_next);
2965
2966 pr_warn("Locks in cached chain:");
2967 print_chain_keys_chain(chain);
2968
2969 pr_warn("\nstack backtrace:\n");
2970 dump_stack();
2971}
2972#endif
2973
2974
2975
2976
2977
2978
2979
2980static int check_no_collision(struct task_struct *curr,
2981 struct held_lock *hlock,
2982 struct lock_chain *chain)
2983{
2984#ifdef CONFIG_DEBUG_LOCKDEP
2985 int i, j, id;
2986
2987 i = get_first_held_lock(curr, hlock);
2988
2989 if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) {
2990 print_collision(curr, hlock, chain);
2991 return 0;
2992 }
2993
2994 for (j = 0; j < chain->depth - 1; j++, i++) {
2995 id = curr->held_locks[i].class_idx;
2996
2997 if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {
2998 print_collision(curr, hlock, chain);
2999 return 0;
3000 }
3001 }
3002#endif
3003 return 1;
3004}
3005
3006
3007
3008
3009
3010long lockdep_next_lockchain(long i)
3011{
3012 i = find_next_bit(lock_chains_in_use, ARRAY_SIZE(lock_chains), i + 1);
3013 return i < ARRAY_SIZE(lock_chains) ? i : -2;
3014}
3015
3016unsigned long lock_chain_count(void)
3017{
3018 return bitmap_weight(lock_chains_in_use, ARRAY_SIZE(lock_chains));
3019}
3020
3021
3022static struct lock_chain *alloc_lock_chain(void)
3023{
3024 int idx = find_first_zero_bit(lock_chains_in_use,
3025 ARRAY_SIZE(lock_chains));
3026
3027 if (unlikely(idx >= ARRAY_SIZE(lock_chains)))
3028 return NULL;
3029 __set_bit(idx, lock_chains_in_use);
3030 return lock_chains + idx;
3031}
3032
3033
3034
3035
3036
3037
3038
3039
3040static inline int add_chain_cache(struct task_struct *curr,
3041 struct held_lock *hlock,
3042 u64 chain_key)
3043{
3044 struct lock_class *class = hlock_class(hlock);
3045 struct hlist_head *hash_head = chainhashentry(chain_key);
3046 struct lock_chain *chain;
3047 int i, j;
3048
3049
3050
3051
3052
3053
3054 if (lockdep_assert_locked())
3055 return 0;
3056
3057 chain = alloc_lock_chain();
3058 if (!chain) {
3059 if (!debug_locks_off_graph_unlock())
3060 return 0;
3061
3062 print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
3063 dump_stack();
3064 return 0;
3065 }
3066 chain->chain_key = chain_key;
3067 chain->irq_context = hlock->irq_context;
3068 i = get_first_held_lock(curr, hlock);
3069 chain->depth = curr->lockdep_depth + 1 - i;
3070
3071 BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks));
3072 BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks));
3073 BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes));
3074
3075 j = alloc_chain_hlocks(chain->depth);
3076 if (j < 0) {
3077 if (!debug_locks_off_graph_unlock())
3078 return 0;
3079
3080 print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
3081 dump_stack();
3082 return 0;
3083 }
3084
3085 chain->base = j;
3086 for (j = 0; j < chain->depth - 1; j++, i++) {
3087 int lock_id = curr->held_locks[i].class_idx;
3088
3089 chain_hlocks[chain->base + j] = lock_id;
3090 }
3091 chain_hlocks[chain->base + j] = class - lock_classes;
3092 hlist_add_head_rcu(&chain->entry, hash_head);
3093 debug_atomic_inc(chain_lookup_misses);
3094 inc_chains(chain->irq_context);
3095
3096 return 1;
3097}
3098
3099
3100
3101
3102
3103static inline struct lock_chain *lookup_chain_cache(u64 chain_key)
3104{
3105 struct hlist_head *hash_head = chainhashentry(chain_key);
3106 struct lock_chain *chain;
3107
3108 hlist_for_each_entry_rcu(chain, hash_head, entry) {
3109 if (READ_ONCE(chain->chain_key) == chain_key) {
3110 debug_atomic_inc(chain_lookup_hits);
3111 return chain;
3112 }
3113 }
3114 return NULL;
3115}
3116
3117
3118
3119
3120
3121
3122
3123static inline int lookup_chain_cache_add(struct task_struct *curr,
3124 struct held_lock *hlock,
3125 u64 chain_key)
3126{
3127 struct lock_class *class = hlock_class(hlock);
3128 struct lock_chain *chain = lookup_chain_cache(chain_key);
3129
3130 if (chain) {
3131cache_hit:
3132 if (!check_no_collision(curr, hlock, chain))
3133 return 0;
3134
3135 if (very_verbose(class)) {
3136 printk("\nhash chain already cached, key: "
3137 "%016Lx tail class: [%px] %s\n",
3138 (unsigned long long)chain_key,
3139 class->key, class->name);
3140 }
3141
3142 return 0;
3143 }
3144
3145 if (very_verbose(class)) {
3146 printk("\nnew hash chain, key: %016Lx tail class: [%px] %s\n",
3147 (unsigned long long)chain_key, class->key, class->name);
3148 }
3149
3150 if (!graph_lock())
3151 return 0;
3152
3153
3154
3155
3156 chain = lookup_chain_cache(chain_key);
3157 if (chain) {
3158 graph_unlock();
3159 goto cache_hit;
3160 }
3161
3162 if (!add_chain_cache(curr, hlock, chain_key))
3163 return 0;
3164
3165 return 1;
3166}
3167
3168static int validate_chain(struct task_struct *curr,
3169 struct held_lock *hlock,
3170 int chain_head, u64 chain_key)
3171{
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182 if (!hlock->trylock && hlock->check &&
3183 lookup_chain_cache_add(curr, hlock, chain_key)) {
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202 int ret = check_deadlock(curr, hlock);
3203
3204 if (!ret)
3205 return 0;
3206
3207
3208
3209
3210
3211 if (ret == 2)
3212 hlock->read = 2;
3213
3214
3215
3216
3217 if (!chain_head && ret != 2) {
3218 if (!check_prevs_add(curr, hlock))
3219 return 0;
3220 }
3221
3222 graph_unlock();
3223 } else {
3224
3225 if (unlikely(!debug_locks))
3226 return 0;
3227 }
3228
3229 return 1;
3230}
3231#else
3232static inline int validate_chain(struct task_struct *curr,
3233 struct held_lock *hlock,
3234 int chain_head, u64 chain_key)
3235{
3236 return 1;
3237}
3238
3239static void init_chain_block_buckets(void) { }
3240#endif
3241
3242
3243
3244
3245
3246static void check_chain_key(struct task_struct *curr)
3247{
3248#ifdef CONFIG_DEBUG_LOCKDEP
3249 struct held_lock *hlock, *prev_hlock = NULL;
3250 unsigned int i;
3251 u64 chain_key = INITIAL_CHAIN_KEY;
3252
3253 for (i = 0; i < curr->lockdep_depth; i++) {
3254 hlock = curr->held_locks + i;
3255 if (chain_key != hlock->prev_chain_key) {
3256 debug_locks_off();
3257
3258
3259
3260
3261 WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
3262 curr->lockdep_depth, i,
3263 (unsigned long long)chain_key,
3264 (unsigned long long)hlock->prev_chain_key);
3265 return;
3266 }
3267
3268
3269
3270
3271
3272 if (DEBUG_LOCKS_WARN_ON(!test_bit(hlock->class_idx, lock_classes_in_use)))
3273 return;
3274
3275 if (prev_hlock && (prev_hlock->irq_context !=
3276 hlock->irq_context))
3277 chain_key = INITIAL_CHAIN_KEY;
3278 chain_key = iterate_chain_key(chain_key, hlock->class_idx);
3279 prev_hlock = hlock;
3280 }
3281 if (chain_key != curr->curr_chain_key) {
3282 debug_locks_off();
3283
3284
3285
3286
3287 WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
3288 curr->lockdep_depth, i,
3289 (unsigned long long)chain_key,
3290 (unsigned long long)curr->curr_chain_key);
3291 }
3292#endif
3293}
3294
3295#ifdef CONFIG_PROVE_LOCKING
3296static int mark_lock(struct task_struct *curr, struct held_lock *this,
3297 enum lock_usage_bit new_bit);
3298
3299static void print_usage_bug_scenario(struct held_lock *lock)
3300{
3301 struct lock_class *class = hlock_class(lock);
3302
3303 printk(" Possible unsafe locking scenario:\n\n");
3304 printk(" CPU0\n");
3305 printk(" ----\n");
3306 printk(" lock(");
3307 __print_lock_name(class);
3308 printk(KERN_CONT ");\n");
3309 printk(" <Interrupt>\n");
3310 printk(" lock(");
3311 __print_lock_name(class);
3312 printk(KERN_CONT ");\n");
3313 printk("\n *** DEADLOCK ***\n\n");
3314}
3315
3316static void
3317print_usage_bug(struct task_struct *curr, struct held_lock *this,
3318 enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
3319{
3320 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
3321 return;
3322
3323 pr_warn("\n");
3324 pr_warn("================================\n");
3325 pr_warn("WARNING: inconsistent lock state\n");
3326 print_kernel_ident();
3327 pr_warn("--------------------------------\n");
3328
3329 pr_warn("inconsistent {%s} -> {%s} usage.\n",
3330 usage_str[prev_bit], usage_str[new_bit]);
3331
3332 pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
3333 curr->comm, task_pid_nr(curr),
3334 lockdep_hardirq_context(), hardirq_count() >> HARDIRQ_SHIFT,
3335 lockdep_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
3336 lockdep_hardirqs_enabled(),
3337 lockdep_softirqs_enabled(curr));
3338 print_lock(this);
3339
3340 pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]);
3341 print_lock_trace(hlock_class(this)->usage_traces[prev_bit], 1);
3342
3343 print_irqtrace_events(curr);
3344 pr_warn("\nother info that might help us debug this:\n");
3345 print_usage_bug_scenario(this);
3346
3347 lockdep_print_held_locks(curr);
3348
3349 pr_warn("\nstack backtrace:\n");
3350 dump_stack();
3351}
3352
3353
3354
3355
3356static inline int
3357valid_state(struct task_struct *curr, struct held_lock *this,
3358 enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
3359{
3360 if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) {
3361 print_usage_bug(curr, this, bad_bit, new_bit);
3362 return 0;
3363 }
3364 return 1;
3365}
3366
3367
3368
3369
3370
3371static void
3372print_irq_inversion_bug(struct task_struct *curr,
3373 struct lock_list *root, struct lock_list *other,
3374 struct held_lock *this, int forwards,
3375 const char *irqclass)
3376{
3377 struct lock_list *entry = other;
3378 struct lock_list *middle = NULL;
3379 int depth;
3380
3381 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
3382 return;
3383
3384 pr_warn("\n");
3385 pr_warn("========================================================\n");
3386 pr_warn("WARNING: possible irq lock inversion dependency detected\n");
3387 print_kernel_ident();
3388 pr_warn("--------------------------------------------------------\n");
3389 pr_warn("%s/%d just changed the state of lock:\n",
3390 curr->comm, task_pid_nr(curr));
3391 print_lock(this);
3392 if (forwards)
3393 pr_warn("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
3394 else
3395 pr_warn("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
3396 print_lock_name(other->class);
3397 pr_warn("\n\nand interrupts could create inverse lock ordering between them.\n\n");
3398
3399 pr_warn("\nother info that might help us debug this:\n");
3400
3401
3402 depth = get_lock_depth(other);
3403 do {
3404 if (depth == 0 && (entry != root)) {
3405 pr_warn("lockdep:%s bad path found in chain graph\n", __func__);
3406 break;
3407 }
3408 middle = entry;
3409 entry = get_lock_parent(entry);
3410 depth--;
3411 } while (entry && entry != root && (depth >= 0));
3412 if (forwards)
3413 print_irq_lock_scenario(root, other,
3414 middle ? middle->class : root->class, other->class);
3415 else
3416 print_irq_lock_scenario(other, root,
3417 middle ? middle->class : other->class, root->class);
3418
3419 lockdep_print_held_locks(curr);
3420
3421 pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
3422 root->trace = save_trace();
3423 if (!root->trace)
3424 return;
3425 print_shortest_lock_dependencies(other, root);
3426
3427 pr_warn("\nstack backtrace:\n");
3428 dump_stack();
3429}
3430
3431
3432
3433
3434
3435static int
3436check_usage_forwards(struct task_struct *curr, struct held_lock *this,
3437 enum lock_usage_bit bit, const char *irqclass)
3438{
3439 int ret;
3440 struct lock_list root;
3441 struct lock_list *target_entry;
3442
3443 root.parent = NULL;
3444 root.class = hlock_class(this);
3445 ret = find_usage_forwards(&root, lock_flag(bit), &target_entry);
3446 if (ret < 0) {
3447 print_bfs_bug(ret);
3448 return 0;
3449 }
3450 if (ret == 1)
3451 return ret;
3452
3453 print_irq_inversion_bug(curr, &root, target_entry,
3454 this, 1, irqclass);
3455 return 0;
3456}
3457
3458
3459
3460
3461
3462static int
3463check_usage_backwards(struct task_struct *curr, struct held_lock *this,
3464 enum lock_usage_bit bit, const char *irqclass)
3465{
3466 int ret;
3467 struct lock_list root;
3468 struct lock_list *target_entry;
3469
3470 root.parent = NULL;
3471 root.class = hlock_class(this);
3472 ret = find_usage_backwards(&root, lock_flag(bit), &target_entry);
3473 if (ret < 0) {
3474 print_bfs_bug(ret);
3475 return 0;
3476 }
3477 if (ret == 1)
3478 return ret;
3479
3480 print_irq_inversion_bug(curr, &root, target_entry,
3481 this, 0, irqclass);
3482 return 0;
3483}
3484
3485void print_irqtrace_events(struct task_struct *curr)
3486{
3487 const struct irqtrace_events *trace = &curr->irqtrace;
3488
3489 printk("irq event stamp: %u\n", trace->irq_events);
3490 printk("hardirqs last enabled at (%u): [<%px>] %pS\n",
3491 trace->hardirq_enable_event, (void *)trace->hardirq_enable_ip,
3492 (void *)trace->hardirq_enable_ip);
3493 printk("hardirqs last disabled at (%u): [<%px>] %pS\n",
3494 trace->hardirq_disable_event, (void *)trace->hardirq_disable_ip,
3495 (void *)trace->hardirq_disable_ip);
3496 printk("softirqs last enabled at (%u): [<%px>] %pS\n",
3497 trace->softirq_enable_event, (void *)trace->softirq_enable_ip,
3498 (void *)trace->softirq_enable_ip);
3499 printk("softirqs last disabled at (%u): [<%px>] %pS\n",
3500 trace->softirq_disable_event, (void *)trace->softirq_disable_ip,
3501 (void *)trace->softirq_disable_ip);
3502}
3503
3504static int HARDIRQ_verbose(struct lock_class *class)
3505{
3506#if HARDIRQ_VERBOSE
3507 return class_filter(class);
3508#endif
3509 return 0;
3510}
3511
3512static int SOFTIRQ_verbose(struct lock_class *class)
3513{
3514#if SOFTIRQ_VERBOSE
3515 return class_filter(class);
3516#endif
3517 return 0;
3518}
3519
3520#define STRICT_READ_CHECKS 1
3521
3522static int (*state_verbose_f[])(struct lock_class *class) = {
3523#define LOCKDEP_STATE(__STATE) \
3524 __STATE##_verbose,
3525#include "lockdep_states.h"
3526#undef LOCKDEP_STATE
3527};
3528
3529static inline int state_verbose(enum lock_usage_bit bit,
3530 struct lock_class *class)
3531{
3532 return state_verbose_f[bit >> LOCK_USAGE_DIR_MASK](class);
3533}
3534
3535typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
3536 enum lock_usage_bit bit, const char *name);
3537
3538static int
3539mark_lock_irq(struct task_struct *curr, struct held_lock *this,
3540 enum lock_usage_bit new_bit)
3541{
3542 int excl_bit = exclusive_bit(new_bit);
3543 int read = new_bit & LOCK_USAGE_READ_MASK;
3544 int dir = new_bit & LOCK_USAGE_DIR_MASK;
3545
3546
3547
3548
3549
3550
3551
3552
3553 check_usage_f usage = dir ?
3554 check_usage_backwards : check_usage_forwards;
3555
3556
3557
3558
3559
3560 if (!valid_state(curr, this, new_bit, excl_bit))
3561 return 0;
3562
3563
3564
3565
3566
3567 if ((!read || STRICT_READ_CHECKS) &&
3568 !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK)))
3569 return 0;
3570
3571
3572
3573
3574 if (!read) {
3575 if (!valid_state(curr, this, new_bit, excl_bit + LOCK_USAGE_READ_MASK))
3576 return 0;
3577
3578 if (STRICT_READ_CHECKS &&
3579 !usage(curr, this, excl_bit + LOCK_USAGE_READ_MASK,
3580 state_name(new_bit + LOCK_USAGE_READ_MASK)))
3581 return 0;
3582 }
3583
3584 if (state_verbose(new_bit, hlock_class(this)))
3585 return 2;
3586
3587 return 1;
3588}
3589
3590
3591
3592
3593static int
3594mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit)
3595{
3596 struct held_lock *hlock;
3597 int i;
3598
3599 for (i = 0; i < curr->lockdep_depth; i++) {
3600 enum lock_usage_bit hlock_bit = base_bit;
3601 hlock = curr->held_locks + i;
3602
3603 if (hlock->read)
3604 hlock_bit += LOCK_USAGE_READ_MASK;
3605
3606 BUG_ON(hlock_bit >= LOCK_USAGE_STATES);
3607
3608 if (!hlock->check)
3609 continue;
3610
3611 if (!mark_lock(curr, hlock, hlock_bit))
3612 return 0;
3613 }
3614
3615 return 1;
3616}
3617
3618
3619
3620
3621static void __trace_hardirqs_on_caller(void)
3622{
3623 struct task_struct *curr = current;
3624
3625
3626
3627
3628
3629 if (!mark_held_locks(curr, LOCK_ENABLED_HARDIRQ))
3630 return;
3631
3632
3633
3634
3635
3636 if (curr->softirqs_enabled)
3637 mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ);
3638}
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649void lockdep_hardirqs_on_prepare(unsigned long ip)
3650{
3651 if (unlikely(!debug_locks))
3652 return;
3653
3654
3655
3656
3657 if (unlikely(in_nmi()))
3658 return;
3659
3660 if (unlikely(current->lockdep_recursion & LOCKDEP_RECURSION_MASK))
3661 return;
3662
3663 if (unlikely(lockdep_hardirqs_enabled())) {
3664
3665
3666
3667
3668
3669 __debug_atomic_inc(redundant_hardirqs_on);
3670 return;
3671 }
3672
3673
3674
3675
3676
3677
3678 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3679 return;
3680
3681
3682
3683
3684 if (DEBUG_LOCKS_WARN_ON(early_boot_irqs_disabled))
3685 return;
3686
3687
3688
3689
3690
3691 if (DEBUG_LOCKS_WARN_ON(lockdep_hardirq_context()))
3692 return;
3693
3694 current->hardirq_chain_key = current->curr_chain_key;
3695
3696 current->lockdep_recursion++;
3697 __trace_hardirqs_on_caller();
3698 lockdep_recursion_finish();
3699}
3700EXPORT_SYMBOL_GPL(lockdep_hardirqs_on_prepare);
3701
3702void noinstr lockdep_hardirqs_on(unsigned long ip)
3703{
3704 struct irqtrace_events *trace = ¤t->irqtrace;
3705
3706 if (unlikely(!debug_locks))
3707 return;
3708
3709
3710
3711
3712
3713
3714
3715
3716 if (unlikely(in_nmi())) {
3717 if (!IS_ENABLED(CONFIG_TRACE_IRQFLAGS_NMI))
3718 return;
3719
3720
3721
3722
3723
3724
3725
3726 goto skip_checks;
3727 }
3728
3729 if (unlikely(current->lockdep_recursion & LOCKDEP_RECURSION_MASK))
3730 return;
3731
3732 if (lockdep_hardirqs_enabled()) {
3733
3734
3735
3736
3737
3738 __debug_atomic_inc(redundant_hardirqs_on);
3739 return;
3740 }
3741
3742
3743
3744
3745
3746
3747 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3748 return;
3749
3750
3751
3752
3753
3754 DEBUG_LOCKS_WARN_ON(current->hardirq_chain_key !=
3755 current->curr_chain_key);
3756
3757skip_checks:
3758
3759 __this_cpu_write(hardirqs_enabled, 1);
3760 trace->hardirq_enable_ip = ip;
3761 trace->hardirq_enable_event = ++trace->irq_events;
3762 debug_atomic_inc(hardirqs_on_events);
3763}
3764EXPORT_SYMBOL_GPL(lockdep_hardirqs_on);
3765
3766
3767
3768
3769void noinstr lockdep_hardirqs_off(unsigned long ip)
3770{
3771 if (unlikely(!debug_locks))
3772 return;
3773
3774
3775
3776
3777
3778
3779 if (in_nmi()) {
3780 if (!IS_ENABLED(CONFIG_TRACE_IRQFLAGS_NMI))
3781 return;
3782 } else if (current->lockdep_recursion & LOCKDEP_RECURSION_MASK)
3783 return;
3784
3785
3786
3787
3788
3789 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3790 return;
3791
3792 if (lockdep_hardirqs_enabled()) {
3793 struct irqtrace_events *trace = ¤t->irqtrace;
3794
3795
3796
3797
3798 __this_cpu_write(hardirqs_enabled, 0);
3799 trace->hardirq_disable_ip = ip;
3800 trace->hardirq_disable_event = ++trace->irq_events;
3801 debug_atomic_inc(hardirqs_off_events);
3802 } else {
3803 debug_atomic_inc(redundant_hardirqs_off);
3804 }
3805}
3806EXPORT_SYMBOL_GPL(lockdep_hardirqs_off);
3807
3808
3809
3810
3811void lockdep_softirqs_on(unsigned long ip)
3812{
3813 struct irqtrace_events *trace = ¤t->irqtrace;
3814
3815 if (unlikely(!debug_locks || current->lockdep_recursion))
3816 return;
3817
3818
3819
3820
3821
3822 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3823 return;
3824
3825 if (current->softirqs_enabled) {
3826 debug_atomic_inc(redundant_softirqs_on);
3827 return;
3828 }
3829
3830 current->lockdep_recursion++;
3831
3832
3833
3834 current->softirqs_enabled = 1;
3835 trace->softirq_enable_ip = ip;
3836 trace->softirq_enable_event = ++trace->irq_events;
3837 debug_atomic_inc(softirqs_on_events);
3838
3839
3840
3841
3842
3843 if (lockdep_hardirqs_enabled())
3844 mark_held_locks(current, LOCK_ENABLED_SOFTIRQ);
3845 lockdep_recursion_finish();
3846}
3847
3848
3849
3850
3851void lockdep_softirqs_off(unsigned long ip)
3852{
3853 if (unlikely(!debug_locks || current->lockdep_recursion))
3854 return;
3855
3856
3857
3858
3859 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3860 return;
3861
3862 if (current->softirqs_enabled) {
3863 struct irqtrace_events *trace = ¤t->irqtrace;
3864
3865
3866
3867
3868 current->softirqs_enabled = 0;
3869 trace->softirq_disable_ip = ip;
3870 trace->softirq_disable_event = ++trace->irq_events;
3871 debug_atomic_inc(softirqs_off_events);
3872
3873
3874
3875 DEBUG_LOCKS_WARN_ON(!softirq_count());
3876 } else
3877 debug_atomic_inc(redundant_softirqs_off);
3878}
3879
3880static int
3881mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
3882{
3883 if (!check)
3884 goto lock_used;
3885
3886
3887
3888
3889
3890 if (!hlock->trylock) {
3891 if (hlock->read) {
3892 if (lockdep_hardirq_context())
3893 if (!mark_lock(curr, hlock,
3894 LOCK_USED_IN_HARDIRQ_READ))
3895 return 0;
3896 if (curr->softirq_context)
3897 if (!mark_lock(curr, hlock,
3898 LOCK_USED_IN_SOFTIRQ_READ))
3899 return 0;
3900 } else {
3901 if (lockdep_hardirq_context())
3902 if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
3903 return 0;
3904 if (curr->softirq_context)
3905 if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
3906 return 0;
3907 }
3908 }
3909 if (!hlock->hardirqs_off) {
3910 if (hlock->read) {
3911 if (!mark_lock(curr, hlock,
3912 LOCK_ENABLED_HARDIRQ_READ))
3913 return 0;
3914 if (curr->softirqs_enabled)
3915 if (!mark_lock(curr, hlock,
3916 LOCK_ENABLED_SOFTIRQ_READ))
3917 return 0;
3918 } else {
3919 if (!mark_lock(curr, hlock,
3920 LOCK_ENABLED_HARDIRQ))
3921 return 0;
3922 if (curr->softirqs_enabled)
3923 if (!mark_lock(curr, hlock,
3924 LOCK_ENABLED_SOFTIRQ))
3925 return 0;
3926 }
3927 }
3928
3929lock_used:
3930
3931 if (!mark_lock(curr, hlock, LOCK_USED))
3932 return 0;
3933
3934 return 1;
3935}
3936
3937static inline unsigned int task_irq_context(struct task_struct *task)
3938{
3939 return LOCK_CHAIN_HARDIRQ_CONTEXT * !!lockdep_hardirq_context() +
3940 LOCK_CHAIN_SOFTIRQ_CONTEXT * !!task->softirq_context;
3941}
3942
3943static int separate_irq_context(struct task_struct *curr,
3944 struct held_lock *hlock)
3945{
3946 unsigned int depth = curr->lockdep_depth;
3947
3948
3949
3950
3951 if (depth) {
3952 struct held_lock *prev_hlock;
3953
3954 prev_hlock = curr->held_locks + depth-1;
3955
3956
3957
3958
3959
3960 if (prev_hlock->irq_context != hlock->irq_context)
3961 return 1;
3962 }
3963 return 0;
3964}
3965
3966
3967
3968
3969static int mark_lock(struct task_struct *curr, struct held_lock *this,
3970 enum lock_usage_bit new_bit)
3971{
3972 unsigned int old_mask, new_mask, ret = 1;
3973
3974 if (new_bit >= LOCK_USAGE_STATES) {
3975 DEBUG_LOCKS_WARN_ON(1);
3976 return 0;
3977 }
3978
3979 if (new_bit == LOCK_USED && this->read)
3980 new_bit = LOCK_USED_READ;
3981
3982 new_mask = 1 << new_bit;
3983
3984
3985
3986
3987
3988 if (likely(hlock_class(this)->usage_mask & new_mask))
3989 return 1;
3990
3991 if (!graph_lock())
3992 return 0;
3993
3994
3995
3996 if (unlikely(hlock_class(this)->usage_mask & new_mask))
3997 goto unlock;
3998
3999 old_mask = hlock_class(this)->usage_mask;
4000 hlock_class(this)->usage_mask |= new_mask;
4001
4002
4003
4004
4005
4006 if (new_bit == LOCK_USED || new_bit == LOCK_USED_READ) {
4007 if (old_mask & (LOCKF_USED | LOCKF_USED_READ))
4008 goto unlock;
4009 new_bit = LOCK_USED;
4010 }
4011
4012 if (!(hlock_class(this)->usage_traces[new_bit] = save_trace()))
4013 return 0;
4014
4015 switch (new_bit) {
4016 case LOCK_USED:
4017 debug_atomic_dec(nr_unused_locks);
4018 break;
4019 default:
4020 ret = mark_lock_irq(curr, this, new_bit);
4021 if (!ret)
4022 return 0;
4023 }
4024
4025unlock:
4026 graph_unlock();
4027
4028
4029
4030
4031 if (ret == 2) {
4032 printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
4033 print_lock(this);
4034 print_irqtrace_events(curr);
4035 dump_stack();
4036 }
4037
4038 return ret;
4039}
4040
4041static inline short task_wait_context(struct task_struct *curr)
4042{
4043
4044
4045
4046
4047 if (lockdep_hardirq_context()) {
4048
4049
4050
4051 if (curr->hardirq_threaded || curr->irq_config)
4052 return LD_WAIT_CONFIG;
4053
4054 return LD_WAIT_SPIN;
4055 } else if (curr->softirq_context) {
4056
4057
4058
4059 return LD_WAIT_CONFIG;
4060 }
4061
4062 return LD_WAIT_MAX;
4063}
4064
4065static int
4066print_lock_invalid_wait_context(struct task_struct *curr,
4067 struct held_lock *hlock)
4068{
4069 short curr_inner;
4070
4071 if (!debug_locks_off())
4072 return 0;
4073 if (debug_locks_silent)
4074 return 0;
4075
4076 pr_warn("\n");
4077 pr_warn("=============================\n");
4078 pr_warn("[ BUG: Invalid wait context ]\n");
4079 print_kernel_ident();
4080 pr_warn("-----------------------------\n");
4081
4082 pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
4083 print_lock(hlock);
4084
4085 pr_warn("other info that might help us debug this:\n");
4086
4087 curr_inner = task_wait_context(curr);
4088 pr_warn("context-{%d:%d}\n", curr_inner, curr_inner);
4089
4090 lockdep_print_held_locks(curr);
4091
4092 pr_warn("stack backtrace:\n");
4093 dump_stack();
4094
4095 return 0;
4096}
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113static int check_wait_context(struct task_struct *curr, struct held_lock *next)
4114{
4115 short next_inner = hlock_class(next)->wait_type_inner;
4116 short next_outer = hlock_class(next)->wait_type_outer;
4117 short curr_inner;
4118 int depth;
4119
4120 if (!curr->lockdep_depth || !next_inner || next->trylock)
4121 return 0;
4122
4123 if (!next_outer)
4124 next_outer = next_inner;
4125
4126
4127
4128
4129 for (depth = curr->lockdep_depth - 1; depth >= 0; depth--) {
4130 struct held_lock *prev = curr->held_locks + depth;
4131 if (prev->irq_context != next->irq_context)
4132 break;
4133 }
4134 depth++;
4135
4136 curr_inner = task_wait_context(curr);
4137
4138 for (; depth < curr->lockdep_depth; depth++) {
4139 struct held_lock *prev = curr->held_locks + depth;
4140 short prev_inner = hlock_class(prev)->wait_type_inner;
4141
4142 if (prev_inner) {
4143
4144
4145
4146
4147
4148
4149 curr_inner = min(curr_inner, prev_inner);
4150 }
4151 }
4152
4153 if (next_outer > curr_inner)
4154 return print_lock_invalid_wait_context(curr, next);
4155
4156 return 0;
4157}
4158
4159#else
4160
4161static inline int
4162mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
4163{
4164 return 1;
4165}
4166
4167static inline unsigned int task_irq_context(struct task_struct *task)
4168{
4169 return 0;
4170}
4171
4172static inline int separate_irq_context(struct task_struct *curr,
4173 struct held_lock *hlock)
4174{
4175 return 0;
4176}
4177
4178static inline int check_wait_context(struct task_struct *curr,
4179 struct held_lock *next)
4180{
4181 return 0;
4182}
4183
4184#endif
4185
4186
4187
4188
4189void lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
4190 struct lock_class_key *key, int subclass,
4191 short inner, short outer)
4192{
4193 int i;
4194
4195 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
4196 lock->class_cache[i] = NULL;
4197
4198#ifdef CONFIG_LOCK_STAT
4199 lock->cpu = raw_smp_processor_id();
4200#endif
4201
4202
4203
4204
4205 if (DEBUG_LOCKS_WARN_ON(!name)) {
4206 lock->name = "NULL";
4207 return;
4208 }
4209
4210 lock->name = name;
4211
4212 lock->wait_type_outer = outer;
4213 lock->wait_type_inner = inner;
4214
4215
4216
4217
4218 if (DEBUG_LOCKS_WARN_ON(!key))
4219 return;
4220
4221
4222
4223
4224 if (!static_obj(key) && !is_dynamic_key(key)) {
4225 if (debug_locks)
4226 printk(KERN_ERR "BUG: key %px has not been registered!\n", key);
4227 DEBUG_LOCKS_WARN_ON(1);
4228 return;
4229 }
4230 lock->key = key;
4231
4232 if (unlikely(!debug_locks))
4233 return;
4234
4235 if (subclass) {
4236 unsigned long flags;
4237
4238 if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion))
4239 return;
4240
4241 raw_local_irq_save(flags);
4242 current->lockdep_recursion++;
4243 register_lock_class(lock, subclass, 1);
4244 lockdep_recursion_finish();
4245 raw_local_irq_restore(flags);
4246 }
4247}
4248EXPORT_SYMBOL_GPL(lockdep_init_map_waits);
4249
4250struct lock_class_key __lockdep_no_validate__;
4251EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
4252
4253static void
4254print_lock_nested_lock_not_held(struct task_struct *curr,
4255 struct held_lock *hlock,
4256 unsigned long ip)
4257{
4258 if (!debug_locks_off())
4259 return;
4260 if (debug_locks_silent)
4261 return;
4262
4263 pr_warn("\n");
4264 pr_warn("==================================\n");
4265 pr_warn("WARNING: Nested lock was not taken\n");
4266 print_kernel_ident();
4267 pr_warn("----------------------------------\n");
4268
4269 pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
4270 print_lock(hlock);
4271
4272 pr_warn("\nbut this task is not holding:\n");
4273 pr_warn("%s\n", hlock->nest_lock->name);
4274
4275 pr_warn("\nstack backtrace:\n");
4276 dump_stack();
4277
4278 pr_warn("\nother info that might help us debug this:\n");
4279 lockdep_print_held_locks(curr);
4280
4281 pr_warn("\nstack backtrace:\n");
4282 dump_stack();
4283}
4284
4285static int __lock_is_held(const struct lockdep_map *lock, int read);
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
4296 int trylock, int read, int check, int hardirqs_off,
4297 struct lockdep_map *nest_lock, unsigned long ip,
4298 int references, int pin_count)
4299{
4300 struct task_struct *curr = current;
4301 struct lock_class *class = NULL;
4302 struct held_lock *hlock;
4303 unsigned int depth;
4304 int chain_head = 0;
4305 int class_idx;
4306 u64 chain_key;
4307
4308 if (unlikely(!debug_locks))
4309 return 0;
4310
4311 if (!prove_locking || lock->key == &__lockdep_no_validate__)
4312 check = 0;
4313
4314 if (subclass < NR_LOCKDEP_CACHING_CLASSES)
4315 class = lock->class_cache[subclass];
4316
4317
4318
4319 if (unlikely(!class)) {
4320 class = register_lock_class(lock, subclass, 0);
4321 if (!class)
4322 return 0;
4323 }
4324
4325 debug_class_ops_inc(class);
4326
4327 if (very_verbose(class)) {
4328 printk("\nacquire class [%px] %s", class->key, class->name);
4329 if (class->name_version > 1)
4330 printk(KERN_CONT "#%d", class->name_version);
4331 printk(KERN_CONT "\n");
4332 dump_stack();
4333 }
4334
4335
4336
4337
4338
4339
4340 depth = curr->lockdep_depth;
4341
4342
4343
4344 if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
4345 return 0;
4346
4347 class_idx = class - lock_classes;
4348
4349 if (depth) {
4350 hlock = curr->held_locks + depth - 1;
4351 if (hlock->class_idx == class_idx && nest_lock) {
4352 if (!references)
4353 references++;
4354
4355 if (!hlock->references)
4356 hlock->references++;
4357
4358 hlock->references += references;
4359
4360
4361 if (DEBUG_LOCKS_WARN_ON(hlock->references < references))
4362 return 0;
4363
4364 return 2;
4365 }
4366 }
4367
4368 hlock = curr->held_locks + depth;
4369
4370
4371
4372
4373 if (DEBUG_LOCKS_WARN_ON(!class))
4374 return 0;
4375 hlock->class_idx = class_idx;
4376 hlock->acquire_ip = ip;
4377 hlock->instance = lock;
4378 hlock->nest_lock = nest_lock;
4379 hlock->irq_context = task_irq_context(curr);
4380 hlock->trylock = trylock;
4381 hlock->read = read;
4382 hlock->check = check;
4383 hlock->hardirqs_off = !!hardirqs_off;
4384 hlock->references = references;
4385#ifdef CONFIG_LOCK_STAT
4386 hlock->waittime_stamp = 0;
4387 hlock->holdtime_stamp = lockstat_clock();
4388#endif
4389 hlock->pin_count = pin_count;
4390
4391 if (check_wait_context(curr, hlock))
4392 return 0;
4393
4394
4395 if (!mark_usage(curr, hlock, check))
4396 return 0;
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411 if (DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use)))
4412 return 0;
4413
4414 chain_key = curr->curr_chain_key;
4415 if (!depth) {
4416
4417
4418
4419 if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY))
4420 return 0;
4421 chain_head = 1;
4422 }
4423
4424 hlock->prev_chain_key = chain_key;
4425 if (separate_irq_context(curr, hlock)) {
4426 chain_key = INITIAL_CHAIN_KEY;
4427 chain_head = 1;
4428 }
4429 chain_key = iterate_chain_key(chain_key, class_idx);
4430
4431 if (nest_lock && !__lock_is_held(nest_lock, -1)) {
4432 print_lock_nested_lock_not_held(curr, hlock, ip);
4433 return 0;
4434 }
4435
4436 if (!debug_locks_silent) {
4437 WARN_ON_ONCE(depth && !hlock_class(hlock - 1)->key);
4438 WARN_ON_ONCE(!hlock_class(hlock)->key);
4439 }
4440
4441 if (!validate_chain(curr, hlock, chain_head, chain_key))
4442 return 0;
4443
4444 curr->curr_chain_key = chain_key;
4445 curr->lockdep_depth++;
4446 check_chain_key(curr);
4447#ifdef CONFIG_DEBUG_LOCKDEP
4448 if (unlikely(!debug_locks))
4449 return 0;
4450#endif
4451 if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
4452 debug_locks_off();
4453 print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
4454 printk(KERN_DEBUG "depth: %i max: %lu!\n",
4455 curr->lockdep_depth, MAX_LOCK_DEPTH);
4456
4457 lockdep_print_held_locks(current);
4458 debug_show_all_locks();
4459 dump_stack();
4460
4461 return 0;
4462 }
4463
4464 if (unlikely(curr->lockdep_depth > max_lockdep_depth))
4465 max_lockdep_depth = curr->lockdep_depth;
4466
4467 return 1;
4468}
4469
4470static void print_unlock_imbalance_bug(struct task_struct *curr,
4471 struct lockdep_map *lock,
4472 unsigned long ip)
4473{
4474 if (!debug_locks_off())
4475 return;
4476 if (debug_locks_silent)
4477 return;
4478
4479 pr_warn("\n");
4480 pr_warn("=====================================\n");
4481 pr_warn("WARNING: bad unlock balance detected!\n");
4482 print_kernel_ident();
4483 pr_warn("-------------------------------------\n");
4484 pr_warn("%s/%d is trying to release lock (",
4485 curr->comm, task_pid_nr(curr));
4486 print_lockdep_cache(lock);
4487 pr_cont(") at:\n");
4488 print_ip_sym(KERN_WARNING, ip);
4489 pr_warn("but there are no more locks to release!\n");
4490 pr_warn("\nother info that might help us debug this:\n");
4491 lockdep_print_held_locks(curr);
4492
4493 pr_warn("\nstack backtrace:\n");
4494 dump_stack();
4495}
4496
4497static noinstr int match_held_lock(const struct held_lock *hlock,
4498 const struct lockdep_map *lock)
4499{
4500 if (hlock->instance == lock)
4501 return 1;
4502
4503 if (hlock->references) {
4504 const struct lock_class *class = lock->class_cache[0];
4505
4506 if (!class)
4507 class = look_up_lock_class(lock, 0);
4508
4509
4510
4511
4512
4513
4514
4515 if (!class)
4516 return 0;
4517
4518
4519
4520
4521
4522
4523 if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
4524 return 0;
4525
4526 if (hlock->class_idx == class - lock_classes)
4527 return 1;
4528 }
4529
4530 return 0;
4531}
4532
4533
4534static struct held_lock *find_held_lock(struct task_struct *curr,
4535 struct lockdep_map *lock,
4536 unsigned int depth, int *idx)
4537{
4538 struct held_lock *ret, *hlock, *prev_hlock;
4539 int i;
4540
4541 i = depth - 1;
4542 hlock = curr->held_locks + i;
4543 ret = hlock;
4544 if (match_held_lock(hlock, lock))
4545 goto out;
4546
4547 ret = NULL;
4548 for (i--, prev_hlock = hlock--;
4549 i >= 0;
4550 i--, prev_hlock = hlock--) {
4551
4552
4553
4554 if (prev_hlock->irq_context != hlock->irq_context) {
4555 ret = NULL;
4556 break;
4557 }
4558 if (match_held_lock(hlock, lock)) {
4559 ret = hlock;
4560 break;
4561 }
4562 }
4563
4564out:
4565 *idx = i;
4566 return ret;
4567}
4568
4569static int reacquire_held_locks(struct task_struct *curr, unsigned int depth,
4570 int idx, unsigned int *merged)
4571{
4572 struct held_lock *hlock;
4573 int first_idx = idx;
4574
4575 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
4576 return 0;
4577
4578 for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) {
4579 switch (__lock_acquire(hlock->instance,
4580 hlock_class(hlock)->subclass,
4581 hlock->trylock,
4582 hlock->read, hlock->check,
4583 hlock->hardirqs_off,
4584 hlock->nest_lock, hlock->acquire_ip,
4585 hlock->references, hlock->pin_count)) {
4586 case 0:
4587 return 1;
4588 case 1:
4589 break;
4590 case 2:
4591 *merged += (idx == first_idx);
4592 break;
4593 default:
4594 WARN_ON(1);
4595 return 0;
4596 }
4597 }
4598 return 0;
4599}
4600
4601static int
4602__lock_set_class(struct lockdep_map *lock, const char *name,
4603 struct lock_class_key *key, unsigned int subclass,
4604 unsigned long ip)
4605{
4606 struct task_struct *curr = current;
4607 unsigned int depth, merged = 0;
4608 struct held_lock *hlock;
4609 struct lock_class *class;
4610 int i;
4611
4612 if (unlikely(!debug_locks))
4613 return 0;
4614
4615 depth = curr->lockdep_depth;
4616
4617
4618
4619
4620 if (DEBUG_LOCKS_WARN_ON(!depth))
4621 return 0;
4622
4623 hlock = find_held_lock(curr, lock, depth, &i);
4624 if (!hlock) {
4625 print_unlock_imbalance_bug(curr, lock, ip);
4626 return 0;
4627 }
4628
4629 lockdep_init_map_waits(lock, name, key, 0,
4630 lock->wait_type_inner,
4631 lock->wait_type_outer);
4632 class = register_lock_class(lock, subclass, 0);
4633 hlock->class_idx = class - lock_classes;
4634
4635 curr->lockdep_depth = i;
4636 curr->curr_chain_key = hlock->prev_chain_key;
4637
4638 if (reacquire_held_locks(curr, depth, i, &merged))
4639 return 0;
4640
4641
4642
4643
4644
4645 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged))
4646 return 0;
4647 return 1;
4648}
4649
4650static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip)
4651{
4652 struct task_struct *curr = current;
4653 unsigned int depth, merged = 0;
4654 struct held_lock *hlock;
4655 int i;
4656
4657 if (unlikely(!debug_locks))
4658 return 0;
4659
4660 depth = curr->lockdep_depth;
4661
4662
4663
4664
4665 if (DEBUG_LOCKS_WARN_ON(!depth))
4666 return 0;
4667
4668 hlock = find_held_lock(curr, lock, depth, &i);
4669 if (!hlock) {
4670 print_unlock_imbalance_bug(curr, lock, ip);
4671 return 0;
4672 }
4673
4674 curr->lockdep_depth = i;
4675 curr->curr_chain_key = hlock->prev_chain_key;
4676
4677 WARN(hlock->read, "downgrading a read lock");
4678 hlock->read = 1;
4679 hlock->acquire_ip = ip;
4680
4681 if (reacquire_held_locks(curr, depth, i, &merged))
4682 return 0;
4683
4684
4685 if (DEBUG_LOCKS_WARN_ON(merged))
4686 return 0;
4687
4688
4689
4690
4691
4692 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
4693 return 0;
4694
4695 return 1;
4696}
4697
4698
4699
4700
4701
4702
4703static int
4704__lock_release(struct lockdep_map *lock, unsigned long ip)
4705{
4706 struct task_struct *curr = current;
4707 unsigned int depth, merged = 1;
4708 struct held_lock *hlock;
4709 int i;
4710
4711 if (unlikely(!debug_locks))
4712 return 0;
4713
4714 depth = curr->lockdep_depth;
4715
4716
4717
4718
4719 if (depth <= 0) {
4720 print_unlock_imbalance_bug(curr, lock, ip);
4721 return 0;
4722 }
4723
4724
4725
4726
4727
4728 hlock = find_held_lock(curr, lock, depth, &i);
4729 if (!hlock) {
4730 print_unlock_imbalance_bug(curr, lock, ip);
4731 return 0;
4732 }
4733
4734 if (hlock->instance == lock)
4735 lock_release_holdtime(hlock);
4736
4737 WARN(hlock->pin_count, "releasing a pinned lock\n");
4738
4739 if (hlock->references) {
4740 hlock->references--;
4741 if (hlock->references) {
4742
4743
4744
4745
4746
4747 return 1;
4748 }
4749 }
4750
4751
4752
4753
4754
4755
4756
4757 curr->lockdep_depth = i;
4758 curr->curr_chain_key = hlock->prev_chain_key;
4759
4760
4761
4762
4763
4764 if (i == depth-1)
4765 return 1;
4766
4767 if (reacquire_held_locks(curr, depth, i + 1, &merged))
4768 return 0;
4769
4770
4771
4772
4773
4774
4775 DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged);
4776
4777
4778
4779
4780
4781
4782 return 0;
4783}
4784
4785static __always_inline
4786int __lock_is_held(const struct lockdep_map *lock, int read)
4787{
4788 struct task_struct *curr = current;
4789 int i;
4790
4791 for (i = 0; i < curr->lockdep_depth; i++) {
4792 struct held_lock *hlock = curr->held_locks + i;
4793
4794 if (match_held_lock(hlock, lock)) {
4795 if (read == -1 || hlock->read == read)
4796 return 1;
4797
4798 return 0;
4799 }
4800 }
4801
4802 return 0;
4803}
4804
4805static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock)
4806{
4807 struct pin_cookie cookie = NIL_COOKIE;
4808 struct task_struct *curr = current;
4809 int i;
4810
4811 if (unlikely(!debug_locks))
4812 return cookie;
4813
4814 for (i = 0; i < curr->lockdep_depth; i++) {
4815 struct held_lock *hlock = curr->held_locks + i;
4816
4817 if (match_held_lock(hlock, lock)) {
4818
4819
4820
4821
4822
4823 cookie.val = 1 + (prandom_u32() >> 16);
4824 hlock->pin_count += cookie.val;
4825 return cookie;
4826 }
4827 }
4828
4829 WARN(1, "pinning an unheld lock\n");
4830 return cookie;
4831}
4832
4833static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
4834{
4835 struct task_struct *curr = current;
4836 int i;
4837
4838 if (unlikely(!debug_locks))
4839 return;
4840
4841 for (i = 0; i < curr->lockdep_depth; i++) {
4842 struct held_lock *hlock = curr->held_locks + i;
4843
4844 if (match_held_lock(hlock, lock)) {
4845 hlock->pin_count += cookie.val;
4846 return;
4847 }
4848 }
4849
4850 WARN(1, "pinning an unheld lock\n");
4851}
4852
4853static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
4854{
4855 struct task_struct *curr = current;
4856 int i;
4857
4858 if (unlikely(!debug_locks))
4859 return;
4860
4861 for (i = 0; i < curr->lockdep_depth; i++) {
4862 struct held_lock *hlock = curr->held_locks + i;
4863
4864 if (match_held_lock(hlock, lock)) {
4865 if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
4866 return;
4867
4868 hlock->pin_count -= cookie.val;
4869
4870 if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n"))
4871 hlock->pin_count = 0;
4872
4873 return;
4874 }
4875 }
4876
4877 WARN(1, "unpinning an unheld lock\n");
4878}
4879
4880
4881
4882
4883static void check_flags(unsigned long flags)
4884{
4885#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP)
4886 if (!debug_locks)
4887 return;
4888
4889 if (irqs_disabled_flags(flags)) {
4890 if (DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())) {
4891 printk("possible reason: unannotated irqs-off.\n");
4892 }
4893 } else {
4894 if (DEBUG_LOCKS_WARN_ON(!lockdep_hardirqs_enabled())) {
4895 printk("possible reason: unannotated irqs-on.\n");
4896 }
4897 }
4898
4899
4900
4901
4902
4903
4904 if (!hardirq_count()) {
4905 if (softirq_count()) {
4906
4907 DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
4908 } else {
4909
4910 DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
4911 }
4912 }
4913
4914 if (!debug_locks)
4915 print_irqtrace_events(current);
4916#endif
4917}
4918
4919void lock_set_class(struct lockdep_map *lock, const char *name,
4920 struct lock_class_key *key, unsigned int subclass,
4921 unsigned long ip)
4922{
4923 unsigned long flags;
4924
4925 if (unlikely(current->lockdep_recursion))
4926 return;
4927
4928 raw_local_irq_save(flags);
4929 current->lockdep_recursion++;
4930 check_flags(flags);
4931 if (__lock_set_class(lock, name, key, subclass, ip))
4932 check_chain_key(current);
4933 lockdep_recursion_finish();
4934 raw_local_irq_restore(flags);
4935}
4936EXPORT_SYMBOL_GPL(lock_set_class);
4937
4938void lock_downgrade(struct lockdep_map *lock, unsigned long ip)
4939{
4940 unsigned long flags;
4941
4942 if (unlikely(current->lockdep_recursion))
4943 return;
4944
4945 raw_local_irq_save(flags);
4946 current->lockdep_recursion++;
4947 check_flags(flags);
4948 if (__lock_downgrade(lock, ip))
4949 check_chain_key(current);
4950 lockdep_recursion_finish();
4951 raw_local_irq_restore(flags);
4952}
4953EXPORT_SYMBOL_GPL(lock_downgrade);
4954
4955
4956static void verify_lock_unused(struct lockdep_map *lock, struct held_lock *hlock, int subclass)
4957{
4958#ifdef CONFIG_PROVE_LOCKING
4959 struct lock_class *class = look_up_lock_class(lock, subclass);
4960 unsigned long mask = LOCKF_USED;
4961
4962
4963 if (!class)
4964 return;
4965
4966
4967
4968
4969
4970 if (!hlock->read)
4971 mask |= LOCKF_USED_READ;
4972
4973 if (!(class->usage_mask & mask))
4974 return;
4975
4976 hlock->class_idx = class - lock_classes;
4977
4978 print_usage_bug(current, hlock, LOCK_USED, LOCK_USAGE_STATES);
4979#endif
4980}
4981
4982static bool lockdep_nmi(void)
4983{
4984 if (current->lockdep_recursion & LOCKDEP_RECURSION_MASK)
4985 return false;
4986
4987 if (!in_nmi())
4988 return false;
4989
4990 return true;
4991}
4992
4993
4994
4995
4996
4997void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
4998 int trylock, int read, int check,
4999 struct lockdep_map *nest_lock, unsigned long ip)
5000{
5001 unsigned long flags;
5002
5003 trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
5004
5005 if (unlikely(current->lockdep_recursion)) {
5006
5007 if (lockdep_nmi() && !trylock) {
5008 struct held_lock hlock;
5009
5010 hlock.acquire_ip = ip;
5011 hlock.instance = lock;
5012 hlock.nest_lock = nest_lock;
5013 hlock.irq_context = 2;
5014 hlock.trylock = trylock;
5015 hlock.read = read;
5016 hlock.check = check;
5017 hlock.hardirqs_off = true;
5018 hlock.references = 0;
5019
5020 verify_lock_unused(lock, &hlock, subclass);
5021 }
5022 return;
5023 }
5024
5025 raw_local_irq_save(flags);
5026 check_flags(flags);
5027
5028 current->lockdep_recursion++;
5029 __lock_acquire(lock, subclass, trylock, read, check,
5030 irqs_disabled_flags(flags), nest_lock, ip, 0, 0);
5031 lockdep_recursion_finish();
5032 raw_local_irq_restore(flags);
5033}
5034EXPORT_SYMBOL_GPL(lock_acquire);
5035
5036void lock_release(struct lockdep_map *lock, unsigned long ip)
5037{
5038 unsigned long flags;
5039
5040 trace_lock_release(lock, ip);
5041
5042 if (unlikely(current->lockdep_recursion))
5043 return;
5044
5045 raw_local_irq_save(flags);
5046 check_flags(flags);
5047
5048 current->lockdep_recursion++;
5049 if (__lock_release(lock, ip))
5050 check_chain_key(current);
5051 lockdep_recursion_finish();
5052 raw_local_irq_restore(flags);
5053}
5054EXPORT_SYMBOL_GPL(lock_release);
5055
5056noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
5057{
5058 unsigned long flags;
5059 int ret = 0;
5060
5061 if (unlikely(current->lockdep_recursion))
5062 return 1;
5063
5064 raw_local_irq_save(flags);
5065 check_flags(flags);
5066
5067 current->lockdep_recursion++;
5068 ret = __lock_is_held(lock, read);
5069 lockdep_recursion_finish();
5070 raw_local_irq_restore(flags);
5071
5072 return ret;
5073}
5074EXPORT_SYMBOL_GPL(lock_is_held_type);
5075NOKPROBE_SYMBOL(lock_is_held_type);
5076
5077struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
5078{
5079 struct pin_cookie cookie = NIL_COOKIE;
5080 unsigned long flags;
5081
5082 if (unlikely(current->lockdep_recursion))
5083 return cookie;
5084
5085 raw_local_irq_save(flags);
5086 check_flags(flags);
5087
5088 current->lockdep_recursion++;
5089 cookie = __lock_pin_lock(lock);
5090 lockdep_recursion_finish();
5091 raw_local_irq_restore(flags);
5092
5093 return cookie;
5094}
5095EXPORT_SYMBOL_GPL(lock_pin_lock);
5096
5097void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
5098{
5099 unsigned long flags;
5100
5101 if (unlikely(current->lockdep_recursion))
5102 return;
5103
5104 raw_local_irq_save(flags);
5105 check_flags(flags);
5106
5107 current->lockdep_recursion++;
5108 __lock_repin_lock(lock, cookie);
5109 lockdep_recursion_finish();
5110 raw_local_irq_restore(flags);
5111}
5112EXPORT_SYMBOL_GPL(lock_repin_lock);
5113
5114void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
5115{
5116 unsigned long flags;
5117
5118 if (unlikely(current->lockdep_recursion))
5119 return;
5120
5121 raw_local_irq_save(flags);
5122 check_flags(flags);
5123
5124 current->lockdep_recursion++;
5125 __lock_unpin_lock(lock, cookie);
5126 lockdep_recursion_finish();
5127 raw_local_irq_restore(flags);
5128}
5129EXPORT_SYMBOL_GPL(lock_unpin_lock);
5130
5131#ifdef CONFIG_LOCK_STAT
5132static void print_lock_contention_bug(struct task_struct *curr,
5133 struct lockdep_map *lock,
5134 unsigned long ip)
5135{
5136 if (!debug_locks_off())
5137 return;
5138 if (debug_locks_silent)
5139 return;
5140
5141 pr_warn("\n");
5142 pr_warn("=================================\n");
5143 pr_warn("WARNING: bad contention detected!\n");
5144 print_kernel_ident();
5145 pr_warn("---------------------------------\n");
5146 pr_warn("%s/%d is trying to contend lock (",
5147 curr->comm, task_pid_nr(curr));
5148 print_lockdep_cache(lock);
5149 pr_cont(") at:\n");
5150 print_ip_sym(KERN_WARNING, ip);
5151 pr_warn("but there are no locks held!\n");
5152 pr_warn("\nother info that might help us debug this:\n");
5153 lockdep_print_held_locks(curr);
5154
5155 pr_warn("\nstack backtrace:\n");
5156 dump_stack();
5157}
5158
5159static void
5160__lock_contended(struct lockdep_map *lock, unsigned long ip)
5161{
5162 struct task_struct *curr = current;
5163 struct held_lock *hlock;
5164 struct lock_class_stats *stats;
5165 unsigned int depth;
5166 int i, contention_point, contending_point;
5167
5168 depth = curr->lockdep_depth;
5169
5170
5171
5172
5173 if (DEBUG_LOCKS_WARN_ON(!depth))
5174 return;
5175
5176 hlock = find_held_lock(curr, lock, depth, &i);
5177 if (!hlock) {
5178 print_lock_contention_bug(curr, lock, ip);
5179 return;
5180 }
5181
5182 if (hlock->instance != lock)
5183 return;
5184
5185 hlock->waittime_stamp = lockstat_clock();
5186
5187 contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
5188 contending_point = lock_point(hlock_class(hlock)->contending_point,
5189 lock->ip);
5190
5191 stats = get_lock_stats(hlock_class(hlock));
5192 if (contention_point < LOCKSTAT_POINTS)
5193 stats->contention_point[contention_point]++;
5194 if (contending_point < LOCKSTAT_POINTS)
5195 stats->contending_point[contending_point]++;
5196 if (lock->cpu != smp_processor_id())
5197 stats->bounces[bounce_contended + !!hlock->read]++;
5198}
5199
5200static void
5201__lock_acquired(struct lockdep_map *lock, unsigned long ip)
5202{
5203 struct task_struct *curr = current;
5204 struct held_lock *hlock;
5205 struct lock_class_stats *stats;
5206 unsigned int depth;
5207 u64 now, waittime = 0;
5208 int i, cpu;
5209
5210 depth = curr->lockdep_depth;
5211
5212
5213
5214
5215 if (DEBUG_LOCKS_WARN_ON(!depth))
5216 return;
5217
5218 hlock = find_held_lock(curr, lock, depth, &i);
5219 if (!hlock) {
5220 print_lock_contention_bug(curr, lock, _RET_IP_);
5221 return;
5222 }
5223
5224 if (hlock->instance != lock)
5225 return;
5226
5227 cpu = smp_processor_id();
5228 if (hlock->waittime_stamp) {
5229 now = lockstat_clock();
5230 waittime = now - hlock->waittime_stamp;
5231 hlock->holdtime_stamp = now;
5232 }
5233
5234 stats = get_lock_stats(hlock_class(hlock));
5235 if (waittime) {
5236 if (hlock->read)
5237 lock_time_inc(&stats->read_waittime, waittime);
5238 else
5239 lock_time_inc(&stats->write_waittime, waittime);
5240 }
5241 if (lock->cpu != cpu)
5242 stats->bounces[bounce_acquired + !!hlock->read]++;
5243
5244 lock->cpu = cpu;
5245 lock->ip = ip;
5246}
5247
5248void lock_contended(struct lockdep_map *lock, unsigned long ip)
5249{
5250 unsigned long flags;
5251
5252 trace_lock_acquired(lock, ip);
5253
5254 if (unlikely(!lock_stat || !debug_locks))
5255 return;
5256
5257 if (unlikely(current->lockdep_recursion))
5258 return;
5259
5260 raw_local_irq_save(flags);
5261 check_flags(flags);
5262 current->lockdep_recursion++;
5263 __lock_contended(lock, ip);
5264 lockdep_recursion_finish();
5265 raw_local_irq_restore(flags);
5266}
5267EXPORT_SYMBOL_GPL(lock_contended);
5268
5269void lock_acquired(struct lockdep_map *lock, unsigned long ip)
5270{
5271 unsigned long flags;
5272
5273 trace_lock_contended(lock, ip);
5274
5275 if (unlikely(!lock_stat || !debug_locks))
5276 return;
5277
5278 if (unlikely(current->lockdep_recursion))
5279 return;
5280
5281 raw_local_irq_save(flags);
5282 check_flags(flags);
5283 current->lockdep_recursion++;
5284 __lock_acquired(lock, ip);
5285 lockdep_recursion_finish();
5286 raw_local_irq_restore(flags);
5287}
5288EXPORT_SYMBOL_GPL(lock_acquired);
5289#endif
5290
5291
5292
5293
5294
5295
5296void lockdep_reset(void)
5297{
5298 unsigned long flags;
5299 int i;
5300
5301 raw_local_irq_save(flags);
5302 lockdep_init_task(current);
5303 memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
5304 nr_hardirq_chains = 0;
5305 nr_softirq_chains = 0;
5306 nr_process_chains = 0;
5307 debug_locks = 1;
5308 for (i = 0; i < CHAINHASH_SIZE; i++)
5309 INIT_HLIST_HEAD(chainhash_table + i);
5310 raw_local_irq_restore(flags);
5311}
5312
5313
5314static void remove_class_from_lock_chain(struct pending_free *pf,
5315 struct lock_chain *chain,
5316 struct lock_class *class)
5317{
5318#ifdef CONFIG_PROVE_LOCKING
5319 int i;
5320
5321 for (i = chain->base; i < chain->base + chain->depth; i++) {
5322 if (chain_hlocks[i] != class - lock_classes)
5323 continue;
5324
5325
5326
5327
5328 goto free_lock_chain;
5329 }
5330
5331 return;
5332
5333free_lock_chain:
5334 free_chain_hlocks(chain->base, chain->depth);
5335
5336 WRITE_ONCE(chain->chain_key, INITIAL_CHAIN_KEY);
5337 dec_chains(chain->irq_context);
5338
5339
5340
5341
5342
5343 hlist_del_rcu(&chain->entry);
5344 __set_bit(chain - lock_chains, pf->lock_chains_being_freed);
5345 nr_zapped_lock_chains++;
5346#endif
5347}
5348
5349
5350static void remove_class_from_lock_chains(struct pending_free *pf,
5351 struct lock_class *class)
5352{
5353 struct lock_chain *chain;
5354 struct hlist_head *head;
5355 int i;
5356
5357 for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) {
5358 head = chainhash_table + i;
5359 hlist_for_each_entry_rcu(chain, head, entry) {
5360 remove_class_from_lock_chain(pf, chain, class);
5361 }
5362 }
5363}
5364
5365
5366
5367
5368static void zap_class(struct pending_free *pf, struct lock_class *class)
5369{
5370 struct lock_list *entry;
5371 int i;
5372
5373 WARN_ON_ONCE(!class->key);
5374
5375
5376
5377
5378
5379 for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) {
5380 entry = list_entries + i;
5381 if (entry->class != class && entry->links_to != class)
5382 continue;
5383 __clear_bit(i, list_entries_in_use);
5384 nr_list_entries--;
5385 list_del_rcu(&entry->entry);
5386 }
5387 if (list_empty(&class->locks_after) &&
5388 list_empty(&class->locks_before)) {
5389 list_move_tail(&class->lock_entry, &pf->zapped);
5390 hlist_del_rcu(&class->hash_entry);
5391 WRITE_ONCE(class->key, NULL);
5392 WRITE_ONCE(class->name, NULL);
5393 nr_lock_classes--;
5394 __clear_bit(class - lock_classes, lock_classes_in_use);
5395 } else {
5396 WARN_ONCE(true, "%s() failed for class %s\n", __func__,
5397 class->name);
5398 }
5399
5400 remove_class_from_lock_chains(pf, class);
5401 nr_zapped_classes++;
5402}
5403
5404static void reinit_class(struct lock_class *class)
5405{
5406 void *const p = class;
5407 const unsigned int offset = offsetof(struct lock_class, key);
5408
5409 WARN_ON_ONCE(!class->lock_entry.next);
5410 WARN_ON_ONCE(!list_empty(&class->locks_after));
5411 WARN_ON_ONCE(!list_empty(&class->locks_before));
5412 memset(p + offset, 0, sizeof(*class) - offset);
5413 WARN_ON_ONCE(!class->lock_entry.next);
5414 WARN_ON_ONCE(!list_empty(&class->locks_after));
5415 WARN_ON_ONCE(!list_empty(&class->locks_before));
5416}
5417
5418static inline int within(const void *addr, void *start, unsigned long size)
5419{
5420 return addr >= start && addr < start + size;
5421}
5422
5423static bool inside_selftest(void)
5424{
5425 return current == lockdep_selftest_task_struct;
5426}
5427
5428
5429static struct pending_free *get_pending_free(void)
5430{
5431 return delayed_free.pf + delayed_free.index;
5432}
5433
5434static void free_zapped_rcu(struct rcu_head *cb);
5435
5436
5437
5438
5439
5440static void call_rcu_zapped(struct pending_free *pf)
5441{
5442 WARN_ON_ONCE(inside_selftest());
5443
5444 if (list_empty(&pf->zapped))
5445 return;
5446
5447 if (delayed_free.scheduled)
5448 return;
5449
5450 delayed_free.scheduled = true;
5451
5452 WARN_ON_ONCE(delayed_free.pf + delayed_free.index != pf);
5453 delayed_free.index ^= 1;
5454
5455 call_rcu(&delayed_free.rcu_head, free_zapped_rcu);
5456}
5457
5458
5459static void __free_zapped_classes(struct pending_free *pf)
5460{
5461 struct lock_class *class;
5462
5463 check_data_structures();
5464
5465 list_for_each_entry(class, &pf->zapped, lock_entry)
5466 reinit_class(class);
5467
5468 list_splice_init(&pf->zapped, &free_lock_classes);
5469
5470#ifdef CONFIG_PROVE_LOCKING
5471 bitmap_andnot(lock_chains_in_use, lock_chains_in_use,
5472 pf->lock_chains_being_freed, ARRAY_SIZE(lock_chains));
5473 bitmap_clear(pf->lock_chains_being_freed, 0, ARRAY_SIZE(lock_chains));
5474#endif
5475}
5476
5477static void free_zapped_rcu(struct rcu_head *ch)
5478{
5479 struct pending_free *pf;
5480 unsigned long flags;
5481
5482 if (WARN_ON_ONCE(ch != &delayed_free.rcu_head))
5483 return;
5484
5485 raw_local_irq_save(flags);
5486 lockdep_lock();
5487
5488
5489 pf = delayed_free.pf + (delayed_free.index ^ 1);
5490 __free_zapped_classes(pf);
5491 delayed_free.scheduled = false;
5492
5493
5494
5495
5496 call_rcu_zapped(delayed_free.pf + delayed_free.index);
5497
5498 lockdep_unlock();
5499 raw_local_irq_restore(flags);
5500}
5501
5502
5503
5504
5505
5506
5507
5508static void __lockdep_free_key_range(struct pending_free *pf, void *start,
5509 unsigned long size)
5510{
5511 struct lock_class *class;
5512 struct hlist_head *head;
5513 int i;
5514
5515
5516 for (i = 0; i < CLASSHASH_SIZE; i++) {
5517 head = classhash_table + i;
5518 hlist_for_each_entry_rcu(class, head, hash_entry) {
5519 if (!within(class->key, start, size) &&
5520 !within(class->name, start, size))
5521 continue;
5522 zap_class(pf, class);
5523 }
5524 }
5525}
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535static void lockdep_free_key_range_reg(void *start, unsigned long size)
5536{
5537 struct pending_free *pf;
5538 unsigned long flags;
5539
5540 init_data_structures_once();
5541
5542 raw_local_irq_save(flags);
5543 lockdep_lock();
5544 pf = get_pending_free();
5545 __lockdep_free_key_range(pf, start, size);
5546 call_rcu_zapped(pf);
5547 lockdep_unlock();
5548 raw_local_irq_restore(flags);
5549
5550
5551
5552
5553
5554 synchronize_rcu();
5555}
5556
5557
5558
5559
5560
5561static void lockdep_free_key_range_imm(void *start, unsigned long size)
5562{
5563 struct pending_free *pf = delayed_free.pf;
5564 unsigned long flags;
5565
5566 init_data_structures_once();
5567
5568 raw_local_irq_save(flags);
5569 lockdep_lock();
5570 __lockdep_free_key_range(pf, start, size);
5571 __free_zapped_classes(pf);
5572 lockdep_unlock();
5573 raw_local_irq_restore(flags);
5574}
5575
5576void lockdep_free_key_range(void *start, unsigned long size)
5577{
5578 init_data_structures_once();
5579
5580 if (inside_selftest())
5581 lockdep_free_key_range_imm(start, size);
5582 else
5583 lockdep_free_key_range_reg(start, size);
5584}
5585
5586
5587
5588
5589
5590
5591static bool lock_class_cache_is_registered(struct lockdep_map *lock)
5592{
5593 struct lock_class *class;
5594 struct hlist_head *head;
5595 int i, j;
5596
5597 for (i = 0; i < CLASSHASH_SIZE; i++) {
5598 head = classhash_table + i;
5599 hlist_for_each_entry_rcu(class, head, hash_entry) {
5600 for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
5601 if (lock->class_cache[j] == class)
5602 return true;
5603 }
5604 }
5605 return false;
5606}
5607
5608
5609static void __lockdep_reset_lock(struct pending_free *pf,
5610 struct lockdep_map *lock)
5611{
5612 struct lock_class *class;
5613 int j;
5614
5615
5616
5617
5618 for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
5619
5620
5621
5622 class = look_up_lock_class(lock, j);
5623 if (class)
5624 zap_class(pf, class);
5625 }
5626
5627
5628
5629
5630 if (WARN_ON_ONCE(lock_class_cache_is_registered(lock)))
5631 debug_locks_off();
5632}
5633
5634
5635
5636
5637
5638static void lockdep_reset_lock_reg(struct lockdep_map *lock)
5639{
5640 struct pending_free *pf;
5641 unsigned long flags;
5642 int locked;
5643
5644 raw_local_irq_save(flags);
5645 locked = graph_lock();
5646 if (!locked)
5647 goto out_irq;
5648
5649 pf = get_pending_free();
5650 __lockdep_reset_lock(pf, lock);
5651 call_rcu_zapped(pf);
5652
5653 graph_unlock();
5654out_irq:
5655 raw_local_irq_restore(flags);
5656}
5657
5658
5659
5660
5661
5662static void lockdep_reset_lock_imm(struct lockdep_map *lock)
5663{
5664 struct pending_free *pf = delayed_free.pf;
5665 unsigned long flags;
5666
5667 raw_local_irq_save(flags);
5668 lockdep_lock();
5669 __lockdep_reset_lock(pf, lock);
5670 __free_zapped_classes(pf);
5671 lockdep_unlock();
5672 raw_local_irq_restore(flags);
5673}
5674
5675void lockdep_reset_lock(struct lockdep_map *lock)
5676{
5677 init_data_structures_once();
5678
5679 if (inside_selftest())
5680 lockdep_reset_lock_imm(lock);
5681 else
5682 lockdep_reset_lock_reg(lock);
5683}
5684
5685
5686void lockdep_unregister_key(struct lock_class_key *key)
5687{
5688 struct hlist_head *hash_head = keyhashentry(key);
5689 struct lock_class_key *k;
5690 struct pending_free *pf;
5691 unsigned long flags;
5692 bool found = false;
5693
5694 might_sleep();
5695
5696 if (WARN_ON_ONCE(static_obj(key)))
5697 return;
5698
5699 raw_local_irq_save(flags);
5700 if (!graph_lock())
5701 goto out_irq;
5702
5703 pf = get_pending_free();
5704 hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
5705 if (k == key) {
5706 hlist_del_rcu(&k->hash_entry);
5707 found = true;
5708 break;
5709 }
5710 }
5711 WARN_ON_ONCE(!found);
5712 __lockdep_free_key_range(pf, key, 1);
5713 call_rcu_zapped(pf);
5714 graph_unlock();
5715out_irq:
5716 raw_local_irq_restore(flags);
5717
5718
5719 synchronize_rcu();
5720}
5721EXPORT_SYMBOL_GPL(lockdep_unregister_key);
5722
5723void __init lockdep_init(void)
5724{
5725 printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
5726
5727 printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
5728 printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
5729 printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
5730 printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
5731 printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
5732 printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
5733 printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
5734
5735 printk(" memory used by lock dependency info: %zu kB\n",
5736 (sizeof(lock_classes) +
5737 sizeof(lock_classes_in_use) +
5738 sizeof(classhash_table) +
5739 sizeof(list_entries) +
5740 sizeof(list_entries_in_use) +
5741 sizeof(chainhash_table) +
5742 sizeof(delayed_free)
5743#ifdef CONFIG_PROVE_LOCKING
5744 + sizeof(lock_cq)
5745 + sizeof(lock_chains)
5746 + sizeof(lock_chains_in_use)
5747 + sizeof(chain_hlocks)
5748#endif
5749 ) / 1024
5750 );
5751
5752#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
5753 printk(" memory used for stack traces: %zu kB\n",
5754 (sizeof(stack_trace) + sizeof(stack_trace_hash)) / 1024
5755 );
5756#endif
5757
5758 printk(" per task-struct memory footprint: %zu bytes\n",
5759 sizeof(((struct task_struct *)NULL)->held_locks));
5760}
5761
5762static void
5763print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
5764 const void *mem_to, struct held_lock *hlock)
5765{
5766 if (!debug_locks_off())
5767 return;
5768 if (debug_locks_silent)
5769 return;
5770
5771 pr_warn("\n");
5772 pr_warn("=========================\n");
5773 pr_warn("WARNING: held lock freed!\n");
5774 print_kernel_ident();
5775 pr_warn("-------------------------\n");
5776 pr_warn("%s/%d is freeing memory %px-%px, with a lock still held there!\n",
5777 curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
5778 print_lock(hlock);
5779 lockdep_print_held_locks(curr);
5780
5781 pr_warn("\nstack backtrace:\n");
5782 dump_stack();
5783}
5784
5785static inline int not_in_range(const void* mem_from, unsigned long mem_len,
5786 const void* lock_from, unsigned long lock_len)
5787{
5788 return lock_from + lock_len <= mem_from ||
5789 mem_from + mem_len <= lock_from;
5790}
5791
5792
5793
5794
5795
5796
5797void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
5798{
5799 struct task_struct *curr = current;
5800 struct held_lock *hlock;
5801 unsigned long flags;
5802 int i;
5803
5804 if (unlikely(!debug_locks))
5805 return;
5806
5807 raw_local_irq_save(flags);
5808 for (i = 0; i < curr->lockdep_depth; i++) {
5809 hlock = curr->held_locks + i;
5810
5811 if (not_in_range(mem_from, mem_len, hlock->instance,
5812 sizeof(*hlock->instance)))
5813 continue;
5814
5815 print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
5816 break;
5817 }
5818 raw_local_irq_restore(flags);
5819}
5820EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
5821
5822static void print_held_locks_bug(void)
5823{
5824 if (!debug_locks_off())
5825 return;
5826 if (debug_locks_silent)
5827 return;
5828
5829 pr_warn("\n");
5830 pr_warn("====================================\n");
5831 pr_warn("WARNING: %s/%d still has locks held!\n",
5832 current->comm, task_pid_nr(current));
5833 print_kernel_ident();
5834 pr_warn("------------------------------------\n");
5835 lockdep_print_held_locks(current);
5836 pr_warn("\nstack backtrace:\n");
5837 dump_stack();
5838}
5839
5840void debug_check_no_locks_held(void)
5841{
5842 if (unlikely(current->lockdep_depth > 0))
5843 print_held_locks_bug();
5844}
5845EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
5846
5847#ifdef __KERNEL__
5848void debug_show_all_locks(void)
5849{
5850 struct task_struct *g, *p;
5851
5852 if (unlikely(!debug_locks)) {
5853 pr_warn("INFO: lockdep is turned off.\n");
5854 return;
5855 }
5856 pr_warn("\nShowing all locks held in the system:\n");
5857
5858 rcu_read_lock();
5859 for_each_process_thread(g, p) {
5860 if (!p->lockdep_depth)
5861 continue;
5862 lockdep_print_held_locks(p);
5863 touch_nmi_watchdog();
5864 touch_all_softlockup_watchdogs();
5865 }
5866 rcu_read_unlock();
5867
5868 pr_warn("\n");
5869 pr_warn("=============================================\n\n");
5870}
5871EXPORT_SYMBOL_GPL(debug_show_all_locks);
5872#endif
5873
5874
5875
5876
5877
5878void debug_show_held_locks(struct task_struct *task)
5879{
5880 if (unlikely(!debug_locks)) {
5881 printk("INFO: lockdep is turned off.\n");
5882 return;
5883 }
5884 lockdep_print_held_locks(task);
5885}
5886EXPORT_SYMBOL_GPL(debug_show_held_locks);
5887
5888asmlinkage __visible void lockdep_sys_exit(void)
5889{
5890 struct task_struct *curr = current;
5891
5892 if (unlikely(curr->lockdep_depth)) {
5893 if (!debug_locks_off())
5894 return;
5895 pr_warn("\n");
5896 pr_warn("================================================\n");
5897 pr_warn("WARNING: lock held when returning to user space!\n");
5898 print_kernel_ident();
5899 pr_warn("------------------------------------------------\n");
5900 pr_warn("%s/%d is leaving the kernel with locks still held!\n",
5901 curr->comm, curr->pid);
5902 lockdep_print_held_locks(curr);
5903 }
5904
5905
5906
5907
5908
5909 lockdep_invariant_state(false);
5910}
5911
5912void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
5913{
5914 struct task_struct *curr = current;
5915
5916
5917 pr_warn("\n");
5918 pr_warn("=============================\n");
5919 pr_warn("WARNING: suspicious RCU usage\n");
5920 print_kernel_ident();
5921 pr_warn("-----------------------------\n");
5922 pr_warn("%s:%d %s!\n", file, line, s);
5923 pr_warn("\nother info that might help us debug this:\n\n");
5924 pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
5925 !rcu_lockdep_current_cpu_online()
5926 ? "RCU used illegally from offline CPU!\n"
5927 : "",
5928 rcu_scheduler_active, debug_locks);
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948 if (!rcu_is_watching())
5949 pr_warn("RCU used illegally from extended quiescent state!\n");
5950
5951 lockdep_print_held_locks(curr);
5952 pr_warn("\nstack backtrace:\n");
5953 dump_stack();
5954}
5955EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
5956