diff options
-rw-r--r-- | kernel/lockdep.c | 1171 | ||||
-rw-r--r-- | kernel/lockdep_proc.c | 2 |
2 files changed, 630 insertions, 543 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 05c1261791f4..87ac36425070 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c | |||
@@ -95,25 +95,6 @@ static int lockdep_initialized; | |||
95 | unsigned long nr_list_entries; | 95 | unsigned long nr_list_entries; |
96 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; | 96 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
97 | 97 | ||
98 | #ifdef CONFIG_PROVE_LOCKING | ||
99 | /* | ||
100 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | ||
101 | * with NULL on failure) | ||
102 | */ | ||
103 | static struct lock_list *alloc_list_entry(void) | ||
104 | { | ||
105 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | ||
106 | if (!debug_locks_off_graph_unlock()) | ||
107 | return NULL; | ||
108 | |||
109 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | ||
110 | printk("turning off the locking correctness validator.\n"); | ||
111 | return NULL; | ||
112 | } | ||
113 | return list_entries + nr_list_entries++; | ||
114 | } | ||
115 | #endif | ||
116 | |||
117 | /* | 98 | /* |
118 | * All data structures here are protected by the global debug_lock. | 99 | * All data structures here are protected by the global debug_lock. |
119 | * | 100 | * |
@@ -141,11 +122,6 @@ LIST_HEAD(all_lock_classes); | |||
141 | 122 | ||
142 | static struct list_head classhash_table[CLASSHASH_SIZE]; | 123 | static struct list_head classhash_table[CLASSHASH_SIZE]; |
143 | 124 | ||
144 | unsigned long nr_lock_chains; | ||
145 | #ifdef CONFIG_PROVE_LOCKING | ||
146 | static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; | ||
147 | #endif | ||
148 | |||
149 | /* | 125 | /* |
150 | * We put the lock dependency chains into a hash-table as well, to cache | 126 | * We put the lock dependency chains into a hash-table as well, to cache |
151 | * their existence: | 127 | * their existence: |
@@ -227,26 +203,6 @@ static int verbose(struct lock_class *class) | |||
227 | return 0; | 203 | return 0; |
228 | } | 204 | } |
229 | 205 | ||
230 | #ifdef CONFIG_TRACE_IRQFLAGS | ||
231 | |||
232 | static int hardirq_verbose(struct lock_class *class) | ||
233 | { | ||
234 | #if HARDIRQ_VERBOSE | ||
235 | return class_filter(class); | ||
236 | #endif | ||
237 | return 0; | ||
238 | } | ||
239 | |||
240 | static int softirq_verbose(struct lock_class *class) | ||
241 | { | ||
242 | #if SOFTIRQ_VERBOSE | ||
243 | return class_filter(class); | ||
244 | #endif | ||
245 | return 0; | ||
246 | } | ||
247 | |||
248 | #endif | ||
249 | |||
250 | /* | 206 | /* |
251 | * Stack-trace: tightly packed array of stack backtrace | 207 | * Stack-trace: tightly packed array of stack backtrace |
252 | * addresses. Protected by the graph_lock. | 208 | * addresses. Protected by the graph_lock. |
@@ -486,8 +442,258 @@ static void print_lock_dependencies(struct lock_class *class, int depth) | |||
486 | } | 442 | } |
487 | } | 443 | } |
488 | 444 | ||
445 | static void print_kernel_version(void) | ||
446 | { | ||
447 | printk("%s %.*s\n", init_utsname()->release, | ||
448 | (int)strcspn(init_utsname()->version, " "), | ||
449 | init_utsname()->version); | ||
450 | } | ||
451 | |||
452 | static int very_verbose(struct lock_class *class) | ||
453 | { | ||
454 | #if VERY_VERBOSE | ||
455 | return class_filter(class); | ||
456 | #endif | ||
457 | return 0; | ||
458 | } | ||
459 | |||
460 | /* | ||
461 | * Is this the address of a static object: | ||
462 | */ | ||
463 | static int static_obj(void *obj) | ||
464 | { | ||
465 | unsigned long start = (unsigned long) &_stext, | ||
466 | end = (unsigned long) &_end, | ||
467 | addr = (unsigned long) obj; | ||
468 | #ifdef CONFIG_SMP | ||
469 | int i; | ||
470 | #endif | ||
471 | |||
472 | /* | ||
473 | * static variable? | ||
474 | */ | ||
475 | if ((addr >= start) && (addr < end)) | ||
476 | return 1; | ||
477 | |||
478 | #ifdef CONFIG_SMP | ||
479 | /* | ||
480 | * percpu var? | ||
481 | */ | ||
482 | for_each_possible_cpu(i) { | ||
483 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | ||
484 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | ||
485 | + per_cpu_offset(i); | ||
486 | |||
487 | if ((addr >= start) && (addr < end)) | ||
488 | return 1; | ||
489 | } | ||
490 | #endif | ||
491 | |||
492 | /* | ||
493 | * module var? | ||
494 | */ | ||
495 | return is_module_address(addr); | ||
496 | } | ||
497 | |||
498 | /* | ||
499 | * To make lock name printouts unique, we calculate a unique | ||
500 | * class->name_version generation counter: | ||
501 | */ | ||
502 | static int count_matching_names(struct lock_class *new_class) | ||
503 | { | ||
504 | struct lock_class *class; | ||
505 | int count = 0; | ||
506 | |||
507 | if (!new_class->name) | ||
508 | return 0; | ||
509 | |||
510 | list_for_each_entry(class, &all_lock_classes, lock_entry) { | ||
511 | if (new_class->key - new_class->subclass == class->key) | ||
512 | return class->name_version; | ||
513 | if (class->name && !strcmp(class->name, new_class->name)) | ||
514 | count = max(count, class->name_version); | ||
515 | } | ||
516 | |||
517 | return count + 1; | ||
518 | } | ||
519 | |||
520 | /* | ||
521 | * Register a lock's class in the hash-table, if the class is not present | ||
522 | * yet. Otherwise we look it up. We cache the result in the lock object | ||
523 | * itself, so actual lookup of the hash should be once per lock object. | ||
524 | */ | ||
525 | static inline struct lock_class * | ||
526 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | ||
527 | { | ||
528 | struct lockdep_subclass_key *key; | ||
529 | struct list_head *hash_head; | ||
530 | struct lock_class *class; | ||
531 | |||
532 | #ifdef CONFIG_DEBUG_LOCKDEP | ||
533 | /* | ||
534 | * If the architecture calls into lockdep before initializing | ||
535 | * the hashes then we'll warn about it later. (we cannot printk | ||
536 | * right now) | ||
537 | */ | ||
538 | if (unlikely(!lockdep_initialized)) { | ||
539 | lockdep_init(); | ||
540 | lockdep_init_error = 1; | ||
541 | } | ||
542 | #endif | ||
543 | |||
544 | /* | ||
545 | * Static locks do not have their class-keys yet - for them the key | ||
546 | * is the lock object itself: | ||
547 | */ | ||
548 | if (unlikely(!lock->key)) | ||
549 | lock->key = (void *)lock; | ||
550 | |||
551 | /* | ||
552 | * NOTE: the class-key must be unique. For dynamic locks, a static | ||
553 | * lock_class_key variable is passed in through the mutex_init() | ||
554 | * (or spin_lock_init()) call - which acts as the key. For static | ||
555 | * locks we use the lock object itself as the key. | ||
556 | */ | ||
557 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class)); | ||
558 | |||
559 | key = lock->key->subkeys + subclass; | ||
560 | |||
561 | hash_head = classhashentry(key); | ||
562 | |||
563 | /* | ||
564 | * We can walk the hash lockfree, because the hash only | ||
565 | * grows, and we are careful when adding entries to the end: | ||
566 | */ | ||
567 | list_for_each_entry(class, hash_head, hash_entry) | ||
568 | if (class->key == key) | ||
569 | return class; | ||
570 | |||
571 | return NULL; | ||
572 | } | ||
573 | |||
574 | /* | ||
575 | * Register a lock's class in the hash-table, if the class is not present | ||
576 | * yet. Otherwise we look it up. We cache the result in the lock object | ||
577 | * itself, so actual lookup of the hash should be once per lock object. | ||
578 | */ | ||
579 | static inline struct lock_class * | ||
580 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | ||
581 | { | ||
582 | struct lockdep_subclass_key *key; | ||
583 | struct list_head *hash_head; | ||
584 | struct lock_class *class; | ||
585 | unsigned long flags; | ||
586 | |||
587 | class = look_up_lock_class(lock, subclass); | ||
588 | if (likely(class)) | ||
589 | return class; | ||
590 | |||
591 | /* | ||
592 | * Debug-check: all keys must be persistent! | ||
593 | */ | ||
594 | if (!static_obj(lock->key)) { | ||
595 | debug_locks_off(); | ||
596 | printk("INFO: trying to register non-static key.\n"); | ||
597 | printk("the code is fine but needs lockdep annotation.\n"); | ||
598 | printk("turning off the locking correctness validator.\n"); | ||
599 | dump_stack(); | ||
600 | |||
601 | return NULL; | ||
602 | } | ||
603 | |||
604 | key = lock->key->subkeys + subclass; | ||
605 | hash_head = classhashentry(key); | ||
606 | |||
607 | raw_local_irq_save(flags); | ||
608 | if (!graph_lock()) { | ||
609 | raw_local_irq_restore(flags); | ||
610 | return NULL; | ||
611 | } | ||
612 | /* | ||
613 | * We have to do the hash-walk again, to avoid races | ||
614 | * with another CPU: | ||
615 | */ | ||
616 | list_for_each_entry(class, hash_head, hash_entry) | ||
617 | if (class->key == key) | ||
618 | goto out_unlock_set; | ||
619 | /* | ||
620 | * Allocate a new key from the static array, and add it to | ||
621 | * the hash: | ||
622 | */ | ||
623 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | ||
624 | if (!debug_locks_off_graph_unlock()) { | ||
625 | raw_local_irq_restore(flags); | ||
626 | return NULL; | ||
627 | } | ||
628 | raw_local_irq_restore(flags); | ||
629 | |||
630 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | ||
631 | printk("turning off the locking correctness validator.\n"); | ||
632 | return NULL; | ||
633 | } | ||
634 | class = lock_classes + nr_lock_classes++; | ||
635 | debug_atomic_inc(&nr_unused_locks); | ||
636 | class->key = key; | ||
637 | class->name = lock->name; | ||
638 | class->subclass = subclass; | ||
639 | INIT_LIST_HEAD(&class->lock_entry); | ||
640 | INIT_LIST_HEAD(&class->locks_before); | ||
641 | INIT_LIST_HEAD(&class->locks_after); | ||
642 | class->name_version = count_matching_names(class); | ||
643 | /* | ||
644 | * We use RCU's safe list-add method to make | ||
645 | * parallel walking of the hash-list safe: | ||
646 | */ | ||
647 | list_add_tail_rcu(&class->hash_entry, hash_head); | ||
648 | |||
649 | if (verbose(class)) { | ||
650 | graph_unlock(); | ||
651 | raw_local_irq_restore(flags); | ||
652 | |||
653 | printk("\nnew class %p: %s", class->key, class->name); | ||
654 | if (class->name_version > 1) | ||
655 | printk("#%d", class->name_version); | ||
656 | printk("\n"); | ||
657 | dump_stack(); | ||
658 | |||
659 | raw_local_irq_save(flags); | ||
660 | if (!graph_lock()) { | ||
661 | raw_local_irq_restore(flags); | ||
662 | return NULL; | ||
663 | } | ||
664 | } | ||
665 | out_unlock_set: | ||
666 | graph_unlock(); | ||
667 | raw_local_irq_restore(flags); | ||
668 | |||
669 | if (!subclass || force) | ||
670 | lock->class_cache = class; | ||
671 | |||
672 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | ||
673 | return NULL; | ||
674 | |||
675 | return class; | ||
676 | } | ||
677 | |||
489 | #ifdef CONFIG_PROVE_LOCKING | 678 | #ifdef CONFIG_PROVE_LOCKING |
490 | /* | 679 | /* |
680 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | ||
681 | * with NULL on failure) | ||
682 | */ | ||
683 | static struct lock_list *alloc_list_entry(void) | ||
684 | { | ||
685 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | ||
686 | if (!debug_locks_off_graph_unlock()) | ||
687 | return NULL; | ||
688 | |||
689 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | ||
690 | printk("turning off the locking correctness validator.\n"); | ||
691 | return NULL; | ||
692 | } | ||
693 | return list_entries + nr_list_entries++; | ||
694 | } | ||
695 | |||
696 | /* | ||
491 | * Add a new dependency to the head of the list: | 697 | * Add a new dependency to the head of the list: |
492 | */ | 698 | */ |
493 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | 699 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, |
@@ -546,16 +752,7 @@ print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |||
546 | 752 | ||
547 | return 0; | 753 | return 0; |
548 | } | 754 | } |
549 | #endif | ||
550 | 755 | ||
551 | static void print_kernel_version(void) | ||
552 | { | ||
553 | printk("%s %.*s\n", init_utsname()->release, | ||
554 | (int)strcspn(init_utsname()->version, " "), | ||
555 | init_utsname()->version); | ||
556 | } | ||
557 | |||
558 | #ifdef CONFIG_PROVE_LOCKING | ||
559 | /* | 756 | /* |
560 | * When a circular dependency is detected, print the | 757 | * When a circular dependency is detected, print the |
561 | * header first: | 758 | * header first: |
@@ -646,17 +843,8 @@ check_noncircular(struct lock_class *source, unsigned int depth) | |||
646 | } | 843 | } |
647 | return 1; | 844 | return 1; |
648 | } | 845 | } |
649 | #endif | ||
650 | 846 | ||
651 | static int very_verbose(struct lock_class *class) | ||
652 | { | ||
653 | #if VERY_VERBOSE | ||
654 | return class_filter(class); | ||
655 | #endif | ||
656 | return 0; | ||
657 | } | ||
658 | #ifdef CONFIG_TRACE_IRQFLAGS | 847 | #ifdef CONFIG_TRACE_IRQFLAGS |
659 | |||
660 | /* | 848 | /* |
661 | * Forwards and backwards subgraph searching, for the purposes of | 849 | * Forwards and backwards subgraph searching, for the purposes of |
662 | * proving that two subgraphs can be connected by a new dependency | 850 | * proving that two subgraphs can be connected by a new dependency |
@@ -829,9 +1017,80 @@ check_usage(struct task_struct *curr, struct held_lock *prev, | |||
829 | bit_backwards, bit_forwards, irqclass); | 1017 | bit_backwards, bit_forwards, irqclass); |
830 | } | 1018 | } |
831 | 1019 | ||
1020 | static int | ||
1021 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | ||
1022 | struct held_lock *next) | ||
1023 | { | ||
1024 | /* | ||
1025 | * Prove that the new dependency does not connect a hardirq-safe | ||
1026 | * lock with a hardirq-unsafe lock - to achieve this we search | ||
1027 | * the backwards-subgraph starting at <prev>, and the | ||
1028 | * forwards-subgraph starting at <next>: | ||
1029 | */ | ||
1030 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, | ||
1031 | LOCK_ENABLED_HARDIRQS, "hard")) | ||
1032 | return 0; | ||
1033 | |||
1034 | /* | ||
1035 | * Prove that the new dependency does not connect a hardirq-safe-read | ||
1036 | * lock with a hardirq-unsafe lock - to achieve this we search | ||
1037 | * the backwards-subgraph starting at <prev>, and the | ||
1038 | * forwards-subgraph starting at <next>: | ||
1039 | */ | ||
1040 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, | ||
1041 | LOCK_ENABLED_HARDIRQS, "hard-read")) | ||
1042 | return 0; | ||
1043 | |||
1044 | /* | ||
1045 | * Prove that the new dependency does not connect a softirq-safe | ||
1046 | * lock with a softirq-unsafe lock - to achieve this we search | ||
1047 | * the backwards-subgraph starting at <prev>, and the | ||
1048 | * forwards-subgraph starting at <next>: | ||
1049 | */ | ||
1050 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, | ||
1051 | LOCK_ENABLED_SOFTIRQS, "soft")) | ||
1052 | return 0; | ||
1053 | /* | ||
1054 | * Prove that the new dependency does not connect a softirq-safe-read | ||
1055 | * lock with a softirq-unsafe lock - to achieve this we search | ||
1056 | * the backwards-subgraph starting at <prev>, and the | ||
1057 | * forwards-subgraph starting at <next>: | ||
1058 | */ | ||
1059 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, | ||
1060 | LOCK_ENABLED_SOFTIRQS, "soft")) | ||
1061 | return 0; | ||
1062 | |||
1063 | return 1; | ||
1064 | } | ||
1065 | |||
1066 | static void inc_chains(void) | ||
1067 | { | ||
1068 | if (current->hardirq_context) | ||
1069 | nr_hardirq_chains++; | ||
1070 | else { | ||
1071 | if (current->softirq_context) | ||
1072 | nr_softirq_chains++; | ||
1073 | else | ||
1074 | nr_process_chains++; | ||
1075 | } | ||
1076 | } | ||
1077 | |||
1078 | #else | ||
1079 | |||
1080 | static inline int | ||
1081 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | ||
1082 | struct held_lock *next) | ||
1083 | { | ||
1084 | return 1; | ||
1085 | } | ||
1086 | |||
1087 | static inline void inc_chains(void) | ||
1088 | { | ||
1089 | nr_process_chains++; | ||
1090 | } | ||
1091 | |||
832 | #endif | 1092 | #endif |
833 | 1093 | ||
834 | #ifdef CONFIG_PROVE_LOCKING | ||
835 | static int | 1094 | static int |
836 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | 1095 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, |
837 | struct held_lock *next) | 1096 | struct held_lock *next) |
@@ -931,47 +1190,10 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, | |||
931 | if (!(check_noncircular(next->class, 0))) | 1190 | if (!(check_noncircular(next->class, 0))) |
932 | return print_circular_bug_tail(); | 1191 | return print_circular_bug_tail(); |
933 | 1192 | ||
934 | #ifdef CONFIG_TRACE_IRQFLAGS | 1193 | if (!check_prev_add_irq(curr, prev, next)) |
935 | /* | ||
936 | * Prove that the new dependency does not connect a hardirq-safe | ||
937 | * lock with a hardirq-unsafe lock - to achieve this we search | ||
938 | * the backwards-subgraph starting at <prev>, and the | ||
939 | * forwards-subgraph starting at <next>: | ||
940 | */ | ||
941 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, | ||
942 | LOCK_ENABLED_HARDIRQS, "hard")) | ||
943 | return 0; | ||
944 | |||
945 | /* | ||
946 | * Prove that the new dependency does not connect a hardirq-safe-read | ||
947 | * lock with a hardirq-unsafe lock - to achieve this we search | ||
948 | * the backwards-subgraph starting at <prev>, and the | ||
949 | * forwards-subgraph starting at <next>: | ||
950 | */ | ||
951 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, | ||
952 | LOCK_ENABLED_HARDIRQS, "hard-read")) | ||
953 | return 0; | 1194 | return 0; |
954 | 1195 | ||
955 | /* | 1196 | /* |
956 | * Prove that the new dependency does not connect a softirq-safe | ||
957 | * lock with a softirq-unsafe lock - to achieve this we search | ||
958 | * the backwards-subgraph starting at <prev>, and the | ||
959 | * forwards-subgraph starting at <next>: | ||
960 | */ | ||
961 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, | ||
962 | LOCK_ENABLED_SOFTIRQS, "soft")) | ||
963 | return 0; | ||
964 | /* | ||
965 | * Prove that the new dependency does not connect a softirq-safe-read | ||
966 | * lock with a softirq-unsafe lock - to achieve this we search | ||
967 | * the backwards-subgraph starting at <prev>, and the | ||
968 | * forwards-subgraph starting at <next>: | ||
969 | */ | ||
970 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, | ||
971 | LOCK_ENABLED_SOFTIRQS, "soft")) | ||
972 | return 0; | ||
973 | #endif | ||
974 | /* | ||
975 | * For recursive read-locks we do all the dependency checks, | 1197 | * For recursive read-locks we do all the dependency checks, |
976 | * but we dont store read-triggered dependencies (only | 1198 | * but we dont store read-triggered dependencies (only |
977 | * write-triggered dependencies). This ensures that only the | 1199 | * write-triggered dependencies). This ensures that only the |
@@ -1096,227 +1318,10 @@ out_bug: | |||
1096 | 1318 | ||
1097 | return 0; | 1319 | return 0; |
1098 | } | 1320 | } |
1099 | #endif | ||
1100 | |||
1101 | /* | ||
1102 | * Is this the address of a static object: | ||
1103 | */ | ||
1104 | static int static_obj(void *obj) | ||
1105 | { | ||
1106 | unsigned long start = (unsigned long) &_stext, | ||
1107 | end = (unsigned long) &_end, | ||
1108 | addr = (unsigned long) obj; | ||
1109 | #ifdef CONFIG_SMP | ||
1110 | int i; | ||
1111 | #endif | ||
1112 | |||
1113 | /* | ||
1114 | * static variable? | ||
1115 | */ | ||
1116 | if ((addr >= start) && (addr < end)) | ||
1117 | return 1; | ||
1118 | |||
1119 | #ifdef CONFIG_SMP | ||
1120 | /* | ||
1121 | * percpu var? | ||
1122 | */ | ||
1123 | for_each_possible_cpu(i) { | ||
1124 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | ||
1125 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | ||
1126 | + per_cpu_offset(i); | ||
1127 | |||
1128 | if ((addr >= start) && (addr < end)) | ||
1129 | return 1; | ||
1130 | } | ||
1131 | #endif | ||
1132 | |||
1133 | /* | ||
1134 | * module var? | ||
1135 | */ | ||
1136 | return is_module_address(addr); | ||
1137 | } | ||
1138 | |||
1139 | /* | ||
1140 | * To make lock name printouts unique, we calculate a unique | ||
1141 | * class->name_version generation counter: | ||
1142 | */ | ||
1143 | static int count_matching_names(struct lock_class *new_class) | ||
1144 | { | ||
1145 | struct lock_class *class; | ||
1146 | int count = 0; | ||
1147 | |||
1148 | if (!new_class->name) | ||
1149 | return 0; | ||
1150 | |||
1151 | list_for_each_entry(class, &all_lock_classes, lock_entry) { | ||
1152 | if (new_class->key - new_class->subclass == class->key) | ||
1153 | return class->name_version; | ||
1154 | if (class->name && !strcmp(class->name, new_class->name)) | ||
1155 | count = max(count, class->name_version); | ||
1156 | } | ||
1157 | |||
1158 | return count + 1; | ||
1159 | } | ||
1160 | |||
1161 | /* | ||
1162 | * Register a lock's class in the hash-table, if the class is not present | ||
1163 | * yet. Otherwise we look it up. We cache the result in the lock object | ||
1164 | * itself, so actual lookup of the hash should be once per lock object. | ||
1165 | */ | ||
1166 | static inline struct lock_class * | ||
1167 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | ||
1168 | { | ||
1169 | struct lockdep_subclass_key *key; | ||
1170 | struct list_head *hash_head; | ||
1171 | struct lock_class *class; | ||
1172 | |||
1173 | #ifdef CONFIG_DEBUG_LOCKDEP | ||
1174 | /* | ||
1175 | * If the architecture calls into lockdep before initializing | ||
1176 | * the hashes then we'll warn about it later. (we cannot printk | ||
1177 | * right now) | ||
1178 | */ | ||
1179 | if (unlikely(!lockdep_initialized)) { | ||
1180 | lockdep_init(); | ||
1181 | lockdep_init_error = 1; | ||
1182 | } | ||
1183 | #endif | ||
1184 | |||
1185 | /* | ||
1186 | * Static locks do not have their class-keys yet - for them the key | ||
1187 | * is the lock object itself: | ||
1188 | */ | ||
1189 | if (unlikely(!lock->key)) | ||
1190 | lock->key = (void *)lock; | ||
1191 | |||
1192 | /* | ||
1193 | * NOTE: the class-key must be unique. For dynamic locks, a static | ||
1194 | * lock_class_key variable is passed in through the mutex_init() | ||
1195 | * (or spin_lock_init()) call - which acts as the key. For static | ||
1196 | * locks we use the lock object itself as the key. | ||
1197 | */ | ||
1198 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class)); | ||
1199 | |||
1200 | key = lock->key->subkeys + subclass; | ||
1201 | |||
1202 | hash_head = classhashentry(key); | ||
1203 | |||
1204 | /* | ||
1205 | * We can walk the hash lockfree, because the hash only | ||
1206 | * grows, and we are careful when adding entries to the end: | ||
1207 | */ | ||
1208 | list_for_each_entry(class, hash_head, hash_entry) | ||
1209 | if (class->key == key) | ||
1210 | return class; | ||
1211 | |||
1212 | return NULL; | ||
1213 | } | ||
1214 | |||
1215 | /* | ||
1216 | * Register a lock's class in the hash-table, if the class is not present | ||
1217 | * yet. Otherwise we look it up. We cache the result in the lock object | ||
1218 | * itself, so actual lookup of the hash should be once per lock object. | ||
1219 | */ | ||
1220 | static inline struct lock_class * | ||
1221 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | ||
1222 | { | ||
1223 | struct lockdep_subclass_key *key; | ||
1224 | struct list_head *hash_head; | ||
1225 | struct lock_class *class; | ||
1226 | unsigned long flags; | ||
1227 | |||
1228 | class = look_up_lock_class(lock, subclass); | ||
1229 | if (likely(class)) | ||
1230 | return class; | ||
1231 | |||
1232 | /* | ||
1233 | * Debug-check: all keys must be persistent! | ||
1234 | */ | ||
1235 | if (!static_obj(lock->key)) { | ||
1236 | debug_locks_off(); | ||
1237 | printk("INFO: trying to register non-static key.\n"); | ||
1238 | printk("the code is fine but needs lockdep annotation.\n"); | ||
1239 | printk("turning off the locking correctness validator.\n"); | ||
1240 | dump_stack(); | ||
1241 | 1321 | ||
1242 | return NULL; | 1322 | unsigned long nr_lock_chains; |
1243 | } | 1323 | static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
1244 | |||
1245 | key = lock->key->subkeys + subclass; | ||
1246 | hash_head = classhashentry(key); | ||
1247 | |||
1248 | raw_local_irq_save(flags); | ||
1249 | if (!graph_lock()) { | ||
1250 | raw_local_irq_restore(flags); | ||
1251 | return NULL; | ||
1252 | } | ||
1253 | /* | ||
1254 | * We have to do the hash-walk again, to avoid races | ||
1255 | * with another CPU: | ||
1256 | */ | ||
1257 | list_for_each_entry(class, hash_head, hash_entry) | ||
1258 | if (class->key == key) | ||
1259 | goto out_unlock_set; | ||
1260 | /* | ||
1261 | * Allocate a new key from the static array, and add it to | ||
1262 | * the hash: | ||
1263 | */ | ||
1264 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | ||
1265 | if (!debug_locks_off_graph_unlock()) { | ||
1266 | raw_local_irq_restore(flags); | ||
1267 | return NULL; | ||
1268 | } | ||
1269 | raw_local_irq_restore(flags); | ||
1270 | |||
1271 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | ||
1272 | printk("turning off the locking correctness validator.\n"); | ||
1273 | return NULL; | ||
1274 | } | ||
1275 | class = lock_classes + nr_lock_classes++; | ||
1276 | debug_atomic_inc(&nr_unused_locks); | ||
1277 | class->key = key; | ||
1278 | class->name = lock->name; | ||
1279 | class->subclass = subclass; | ||
1280 | INIT_LIST_HEAD(&class->lock_entry); | ||
1281 | INIT_LIST_HEAD(&class->locks_before); | ||
1282 | INIT_LIST_HEAD(&class->locks_after); | ||
1283 | class->name_version = count_matching_names(class); | ||
1284 | /* | ||
1285 | * We use RCU's safe list-add method to make | ||
1286 | * parallel walking of the hash-list safe: | ||
1287 | */ | ||
1288 | list_add_tail_rcu(&class->hash_entry, hash_head); | ||
1289 | |||
1290 | if (verbose(class)) { | ||
1291 | graph_unlock(); | ||
1292 | raw_local_irq_restore(flags); | ||
1293 | |||
1294 | printk("\nnew class %p: %s", class->key, class->name); | ||
1295 | if (class->name_version > 1) | ||
1296 | printk("#%d", class->name_version); | ||
1297 | printk("\n"); | ||
1298 | dump_stack(); | ||
1299 | |||
1300 | raw_local_irq_save(flags); | ||
1301 | if (!graph_lock()) { | ||
1302 | raw_local_irq_restore(flags); | ||
1303 | return NULL; | ||
1304 | } | ||
1305 | } | ||
1306 | out_unlock_set: | ||
1307 | graph_unlock(); | ||
1308 | raw_local_irq_restore(flags); | ||
1309 | |||
1310 | if (!subclass || force) | ||
1311 | lock->class_cache = class; | ||
1312 | |||
1313 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | ||
1314 | return NULL; | ||
1315 | |||
1316 | return class; | ||
1317 | } | ||
1318 | 1324 | ||
1319 | #ifdef CONFIG_PROVE_LOCKING | ||
1320 | /* | 1325 | /* |
1321 | * Look up a dependency chain. If the key is not present yet then | 1326 | * Look up a dependency chain. If the key is not present yet then |
1322 | * add it and return 1 - in this case the new dependency chain is | 1327 | * add it and return 1 - in this case the new dependency chain is |
@@ -1376,21 +1381,71 @@ cache_hit: | |||
1376 | chain->chain_key = chain_key; | 1381 | chain->chain_key = chain_key; |
1377 | list_add_tail_rcu(&chain->entry, hash_head); | 1382 | list_add_tail_rcu(&chain->entry, hash_head); |
1378 | debug_atomic_inc(&chain_lookup_misses); | 1383 | debug_atomic_inc(&chain_lookup_misses); |
1379 | #ifdef CONFIG_TRACE_IRQFLAGS | 1384 | inc_chains(); |
1380 | if (current->hardirq_context) | 1385 | |
1381 | nr_hardirq_chains++; | 1386 | return 1; |
1382 | else { | 1387 | } |
1383 | if (current->softirq_context) | 1388 | |
1384 | nr_softirq_chains++; | 1389 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, |
1385 | else | 1390 | struct held_lock *hlock, int chain_head) |
1386 | nr_process_chains++; | 1391 | { |
1387 | } | 1392 | /* |
1388 | #else | 1393 | * Trylock needs to maintain the stack of held locks, but it |
1389 | nr_process_chains++; | 1394 | * does not add new dependencies, because trylock can be done |
1390 | #endif | 1395 | * in any order. |
1396 | * | ||
1397 | * We look up the chain_key and do the O(N^2) check and update of | ||
1398 | * the dependencies only if this is a new dependency chain. | ||
1399 | * (If lookup_chain_cache() returns with 1 it acquires | ||
1400 | * graph_lock for us) | ||
1401 | */ | ||
1402 | if (!hlock->trylock && (hlock->check == 2) && | ||
1403 | lookup_chain_cache(curr->curr_chain_key, hlock->class)) { | ||
1404 | /* | ||
1405 | * Check whether last held lock: | ||
1406 | * | ||
1407 | * - is irq-safe, if this lock is irq-unsafe | ||
1408 | * - is softirq-safe, if this lock is hardirq-unsafe | ||
1409 | * | ||
1410 | * And check whether the new lock's dependency graph | ||
1411 | * could lead back to the previous lock. | ||
1412 | * | ||
1413 | * any of these scenarios could lead to a deadlock. If | ||
1414 | * All validations | ||
1415 | */ | ||
1416 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | ||
1417 | |||
1418 | if (!ret) | ||
1419 | return 0; | ||
1420 | /* | ||
1421 | * Mark recursive read, as we jump over it when | ||
1422 | * building dependencies (just like we jump over | ||
1423 | * trylock entries): | ||
1424 | */ | ||
1425 | if (ret == 2) | ||
1426 | hlock->read = 2; | ||
1427 | /* | ||
1428 | * Add dependency only if this lock is not the head | ||
1429 | * of the chain, and if it's not a secondary read-lock: | ||
1430 | */ | ||
1431 | if (!chain_head && ret != 2) | ||
1432 | if (!check_prevs_add(curr, hlock)) | ||
1433 | return 0; | ||
1434 | graph_unlock(); | ||
1435 | } else | ||
1436 | /* after lookup_chain_cache(): */ | ||
1437 | if (unlikely(!debug_locks)) | ||
1438 | return 0; | ||
1391 | 1439 | ||
1392 | return 1; | 1440 | return 1; |
1393 | } | 1441 | } |
1442 | #else | ||
1443 | static inline int validate_chain(struct task_struct *curr, | ||
1444 | struct lockdep_map *lock, struct held_lock *hlock, | ||
1445 | int chain_head) | ||
1446 | { | ||
1447 | return 1; | ||
1448 | } | ||
1394 | #endif | 1449 | #endif |
1395 | 1450 | ||
1396 | /* | 1451 | /* |
@@ -1436,6 +1491,57 @@ static void check_chain_key(struct task_struct *curr) | |||
1436 | #endif | 1491 | #endif |
1437 | } | 1492 | } |
1438 | 1493 | ||
1494 | static int | ||
1495 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | ||
1496 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | ||
1497 | { | ||
1498 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | ||
1499 | return 0; | ||
1500 | |||
1501 | printk("\n=================================\n"); | ||
1502 | printk( "[ INFO: inconsistent lock state ]\n"); | ||
1503 | print_kernel_version(); | ||
1504 | printk( "---------------------------------\n"); | ||
1505 | |||
1506 | printk("inconsistent {%s} -> {%s} usage.\n", | ||
1507 | usage_str[prev_bit], usage_str[new_bit]); | ||
1508 | |||
1509 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | ||
1510 | curr->comm, curr->pid, | ||
1511 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, | ||
1512 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | ||
1513 | trace_hardirqs_enabled(curr), | ||
1514 | trace_softirqs_enabled(curr)); | ||
1515 | print_lock(this); | ||
1516 | |||
1517 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | ||
1518 | print_stack_trace(this->class->usage_traces + prev_bit, 1); | ||
1519 | |||
1520 | print_irqtrace_events(curr); | ||
1521 | printk("\nother info that might help us debug this:\n"); | ||
1522 | lockdep_print_held_locks(curr); | ||
1523 | |||
1524 | printk("\nstack backtrace:\n"); | ||
1525 | dump_stack(); | ||
1526 | |||
1527 | return 0; | ||
1528 | } | ||
1529 | |||
1530 | /* | ||
1531 | * Print out an error if an invalid bit is set: | ||
1532 | */ | ||
1533 | static inline int | ||
1534 | valid_state(struct task_struct *curr, struct held_lock *this, | ||
1535 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | ||
1536 | { | ||
1537 | if (unlikely(this->class->usage_mask & (1 << bad_bit))) | ||
1538 | return print_usage_bug(curr, this, bad_bit, new_bit); | ||
1539 | return 1; | ||
1540 | } | ||
1541 | |||
1542 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | ||
1543 | enum lock_usage_bit new_bit); | ||
1544 | |||
1439 | #ifdef CONFIG_TRACE_IRQFLAGS | 1545 | #ifdef CONFIG_TRACE_IRQFLAGS |
1440 | 1546 | ||
1441 | /* | 1547 | /* |
@@ -1529,90 +1635,30 @@ void print_irqtrace_events(struct task_struct *curr) | |||
1529 | print_ip_sym(curr->softirq_disable_ip); | 1635 | print_ip_sym(curr->softirq_disable_ip); |
1530 | } | 1636 | } |
1531 | 1637 | ||
1532 | #endif | 1638 | static int hardirq_verbose(struct lock_class *class) |
1533 | |||
1534 | static int | ||
1535 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | ||
1536 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | ||
1537 | { | 1639 | { |
1538 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | 1640 | #if HARDIRQ_VERBOSE |
1539 | return 0; | 1641 | return class_filter(class); |
1540 | 1642 | #endif | |
1541 | printk("\n=================================\n"); | ||
1542 | printk( "[ INFO: inconsistent lock state ]\n"); | ||
1543 | print_kernel_version(); | ||
1544 | printk( "---------------------------------\n"); | ||
1545 | |||
1546 | printk("inconsistent {%s} -> {%s} usage.\n", | ||
1547 | usage_str[prev_bit], usage_str[new_bit]); | ||
1548 | |||
1549 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | ||
1550 | curr->comm, curr->pid, | ||
1551 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, | ||
1552 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | ||
1553 | trace_hardirqs_enabled(curr), | ||
1554 | trace_softirqs_enabled(curr)); | ||
1555 | print_lock(this); | ||
1556 | |||
1557 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | ||
1558 | print_stack_trace(this->class->usage_traces + prev_bit, 1); | ||
1559 | |||
1560 | print_irqtrace_events(curr); | ||
1561 | printk("\nother info that might help us debug this:\n"); | ||
1562 | lockdep_print_held_locks(curr); | ||
1563 | |||
1564 | printk("\nstack backtrace:\n"); | ||
1565 | dump_stack(); | ||
1566 | |||
1567 | return 0; | 1643 | return 0; |
1568 | } | 1644 | } |
1569 | 1645 | ||
1570 | /* | 1646 | static int softirq_verbose(struct lock_class *class) |
1571 | * Print out an error if an invalid bit is set: | ||
1572 | */ | ||
1573 | static inline int | ||
1574 | valid_state(struct task_struct *curr, struct held_lock *this, | ||
1575 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | ||
1576 | { | 1647 | { |
1577 | if (unlikely(this->class->usage_mask & (1 << bad_bit))) | 1648 | #if SOFTIRQ_VERBOSE |
1578 | return print_usage_bug(curr, this, bad_bit, new_bit); | 1649 | return class_filter(class); |
1579 | return 1; | 1650 | #endif |
1651 | return 0; | ||
1580 | } | 1652 | } |
1581 | 1653 | ||
1582 | #define STRICT_READ_CHECKS 1 | 1654 | #define STRICT_READ_CHECKS 1 |
1583 | 1655 | ||
1584 | /* | 1656 | static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
1585 | * Mark a lock with a usage bit, and validate the state transition: | 1657 | enum lock_usage_bit new_bit) |
1586 | */ | ||
1587 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | ||
1588 | enum lock_usage_bit new_bit) | ||
1589 | { | 1658 | { |
1590 | unsigned int new_mask = 1 << new_bit, ret = 1; | 1659 | int ret = 1; |
1591 | |||
1592 | /* | ||
1593 | * If already set then do not dirty the cacheline, | ||
1594 | * nor do any checks: | ||
1595 | */ | ||
1596 | if (likely(this->class->usage_mask & new_mask)) | ||
1597 | return 1; | ||
1598 | 1660 | ||
1599 | if (!graph_lock()) | 1661 | switch(new_bit) { |
1600 | return 0; | ||
1601 | /* | ||
1602 | * Make sure we didnt race: | ||
1603 | */ | ||
1604 | if (unlikely(this->class->usage_mask & new_mask)) { | ||
1605 | graph_unlock(); | ||
1606 | return 1; | ||
1607 | } | ||
1608 | |||
1609 | this->class->usage_mask |= new_mask; | ||
1610 | |||
1611 | if (!save_trace(this->class->usage_traces + new_bit)) | ||
1612 | return 0; | ||
1613 | |||
1614 | switch (new_bit) { | ||
1615 | #ifdef CONFIG_TRACE_IRQFLAGS | ||
1616 | case LOCK_USED_IN_HARDIRQ: | 1662 | case LOCK_USED_IN_HARDIRQ: |
1617 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) | 1663 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) |
1618 | return 0; | 1664 | return 0; |
@@ -1771,37 +1817,14 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, | |||
1771 | if (softirq_verbose(this->class)) | 1817 | if (softirq_verbose(this->class)) |
1772 | ret = 2; | 1818 | ret = 2; |
1773 | break; | 1819 | break; |
1774 | #endif | ||
1775 | case LOCK_USED: | ||
1776 | /* | ||
1777 | * Add it to the global list of classes: | ||
1778 | */ | ||
1779 | list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes); | ||
1780 | debug_atomic_dec(&nr_unused_locks); | ||
1781 | break; | ||
1782 | default: | 1820 | default: |
1783 | if (!debug_locks_off_graph_unlock()) | ||
1784 | return 0; | ||
1785 | WARN_ON(1); | 1821 | WARN_ON(1); |
1786 | return 0; | 1822 | break; |
1787 | } | ||
1788 | |||
1789 | graph_unlock(); | ||
1790 | |||
1791 | /* | ||
1792 | * We must printk outside of the graph_lock: | ||
1793 | */ | ||
1794 | if (ret == 2) { | ||
1795 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | ||
1796 | print_lock(this); | ||
1797 | print_irqtrace_events(curr); | ||
1798 | dump_stack(); | ||
1799 | } | 1823 | } |
1800 | 1824 | ||
1801 | return ret; | 1825 | return ret; |
1802 | } | 1826 | } |
1803 | 1827 | ||
1804 | #ifdef CONFIG_TRACE_IRQFLAGS | ||
1805 | /* | 1828 | /* |
1806 | * Mark all held locks with a usage bit: | 1829 | * Mark all held locks with a usage bit: |
1807 | */ | 1830 | */ |
@@ -1984,9 +2007,176 @@ void trace_softirqs_off(unsigned long ip) | |||
1984 | debug_atomic_inc(&redundant_softirqs_off); | 2007 | debug_atomic_inc(&redundant_softirqs_off); |
1985 | } | 2008 | } |
1986 | 2009 | ||
2010 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) | ||
2011 | { | ||
2012 | /* | ||
2013 | * If non-trylock use in a hardirq or softirq context, then | ||
2014 | * mark the lock as used in these contexts: | ||
2015 | */ | ||
2016 | if (!hlock->trylock) { | ||
2017 | if (hlock->read) { | ||
2018 | if (curr->hardirq_context) | ||
2019 | if (!mark_lock(curr, hlock, | ||
2020 | LOCK_USED_IN_HARDIRQ_READ)) | ||
2021 | return 0; | ||
2022 | if (curr->softirq_context) | ||
2023 | if (!mark_lock(curr, hlock, | ||
2024 | LOCK_USED_IN_SOFTIRQ_READ)) | ||
2025 | return 0; | ||
2026 | } else { | ||
2027 | if (curr->hardirq_context) | ||
2028 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | ||
2029 | return 0; | ||
2030 | if (curr->softirq_context) | ||
2031 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | ||
2032 | return 0; | ||
2033 | } | ||
2034 | } | ||
2035 | if (!hlock->hardirqs_off) { | ||
2036 | if (hlock->read) { | ||
2037 | if (!mark_lock(curr, hlock, | ||
2038 | LOCK_ENABLED_HARDIRQS_READ)) | ||
2039 | return 0; | ||
2040 | if (curr->softirqs_enabled) | ||
2041 | if (!mark_lock(curr, hlock, | ||
2042 | LOCK_ENABLED_SOFTIRQS_READ)) | ||
2043 | return 0; | ||
2044 | } else { | ||
2045 | if (!mark_lock(curr, hlock, | ||
2046 | LOCK_ENABLED_HARDIRQS)) | ||
2047 | return 0; | ||
2048 | if (curr->softirqs_enabled) | ||
2049 | if (!mark_lock(curr, hlock, | ||
2050 | LOCK_ENABLED_SOFTIRQS)) | ||
2051 | return 0; | ||
2052 | } | ||
2053 | } | ||
2054 | |||
2055 | return 1; | ||
2056 | } | ||
2057 | |||
2058 | static int separate_irq_context(struct task_struct *curr, | ||
2059 | struct held_lock *hlock) | ||
2060 | { | ||
2061 | unsigned int depth = curr->lockdep_depth; | ||
2062 | |||
2063 | /* | ||
2064 | * Keep track of points where we cross into an interrupt context: | ||
2065 | */ | ||
2066 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | ||
2067 | curr->softirq_context; | ||
2068 | if (depth) { | ||
2069 | struct held_lock *prev_hlock; | ||
2070 | |||
2071 | prev_hlock = curr->held_locks + depth-1; | ||
2072 | /* | ||
2073 | * If we cross into another context, reset the | ||
2074 | * hash key (this also prevents the checking and the | ||
2075 | * adding of the dependency to 'prev'): | ||
2076 | */ | ||
2077 | if (prev_hlock->irq_context != hlock->irq_context) | ||
2078 | return 1; | ||
2079 | } | ||
2080 | return 0; | ||
2081 | } | ||
2082 | |||
2083 | #else | ||
2084 | |||
2085 | static inline | ||
2086 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | ||
2087 | enum lock_usage_bit new_bit) | ||
2088 | { | ||
2089 | WARN_ON(1); | ||
2090 | return 1; | ||
2091 | } | ||
2092 | |||
2093 | static inline int mark_irqflags(struct task_struct *curr, | ||
2094 | struct held_lock *hlock) | ||
2095 | { | ||
2096 | return 1; | ||
2097 | } | ||
2098 | |||
2099 | static inline int separate_irq_context(struct task_struct *curr, | ||
2100 | struct held_lock *hlock) | ||
2101 | { | ||
2102 | return 0; | ||
2103 | } | ||
2104 | |||
1987 | #endif | 2105 | #endif |
1988 | 2106 | ||
1989 | /* | 2107 | /* |
2108 | * Mark a lock with a usage bit, and validate the state transition: | ||
2109 | */ | ||
2110 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | ||
2111 | enum lock_usage_bit new_bit) | ||
2112 | { | ||
2113 | unsigned int new_mask = 1 << new_bit, ret = 1; | ||
2114 | |||
2115 | /* | ||
2116 | * If already set then do not dirty the cacheline, | ||
2117 | * nor do any checks: | ||
2118 | */ | ||
2119 | if (likely(this->class->usage_mask & new_mask)) | ||
2120 | return 1; | ||
2121 | |||
2122 | if (!graph_lock()) | ||
2123 | return 0; | ||
2124 | /* | ||
2125 | * Make sure we didnt race: | ||
2126 | */ | ||
2127 | if (unlikely(this->class->usage_mask & new_mask)) { | ||
2128 | graph_unlock(); | ||
2129 | return 1; | ||
2130 | } | ||
2131 | |||
2132 | this->class->usage_mask |= new_mask; | ||
2133 | |||
2134 | if (!save_trace(this->class->usage_traces + new_bit)) | ||
2135 | return 0; | ||
2136 | |||
2137 | switch (new_bit) { | ||
2138 | case LOCK_USED_IN_HARDIRQ: | ||
2139 | case LOCK_USED_IN_SOFTIRQ: | ||
2140 | case LOCK_USED_IN_HARDIRQ_READ: | ||
2141 | case LOCK_USED_IN_SOFTIRQ_READ: | ||
2142 | case LOCK_ENABLED_HARDIRQS: | ||
2143 | case LOCK_ENABLED_SOFTIRQS: | ||
2144 | case LOCK_ENABLED_HARDIRQS_READ: | ||
2145 | case LOCK_ENABLED_SOFTIRQS_READ: | ||
2146 | ret = mark_lock_irq(curr, this, new_bit); | ||
2147 | if (!ret) | ||
2148 | return 0; | ||
2149 | break; | ||
2150 | case LOCK_USED: | ||
2151 | /* | ||
2152 | * Add it to the global list of classes: | ||
2153 | */ | ||
2154 | list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes); | ||
2155 | debug_atomic_dec(&nr_unused_locks); | ||
2156 | break; | ||
2157 | default: | ||
2158 | if (!debug_locks_off_graph_unlock()) | ||
2159 | return 0; | ||
2160 | WARN_ON(1); | ||
2161 | return 0; | ||
2162 | } | ||
2163 | |||
2164 | graph_unlock(); | ||
2165 | |||
2166 | /* | ||
2167 | * We must printk outside of the graph_lock: | ||
2168 | */ | ||
2169 | if (ret == 2) { | ||
2170 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | ||
2171 | print_lock(this); | ||
2172 | print_irqtrace_events(curr); | ||
2173 | dump_stack(); | ||
2174 | } | ||
2175 | |||
2176 | return ret; | ||
2177 | } | ||
2178 | |||
2179 | /* | ||
1990 | * Initialize a lock instance's lock-class mapping info: | 2180 | * Initialize a lock instance's lock-class mapping info: |
1991 | */ | 2181 | */ |
1992 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | 2182 | void lockdep_init_map(struct lockdep_map *lock, const char *name, |
@@ -2082,56 +2272,13 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |||
2082 | hlock->check = check; | 2272 | hlock->check = check; |
2083 | hlock->hardirqs_off = hardirqs_off; | 2273 | hlock->hardirqs_off = hardirqs_off; |
2084 | 2274 | ||
2085 | if (check != 2) | 2275 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2086 | goto out_calc_hash; | 2276 | return 0; |
2087 | #ifdef CONFIG_TRACE_IRQFLAGS | 2277 | |
2088 | /* | ||
2089 | * If non-trylock use in a hardirq or softirq context, then | ||
2090 | * mark the lock as used in these contexts: | ||
2091 | */ | ||
2092 | if (!trylock) { | ||
2093 | if (read) { | ||
2094 | if (curr->hardirq_context) | ||
2095 | if (!mark_lock(curr, hlock, | ||
2096 | LOCK_USED_IN_HARDIRQ_READ)) | ||
2097 | return 0; | ||
2098 | if (curr->softirq_context) | ||
2099 | if (!mark_lock(curr, hlock, | ||
2100 | LOCK_USED_IN_SOFTIRQ_READ)) | ||
2101 | return 0; | ||
2102 | } else { | ||
2103 | if (curr->hardirq_context) | ||
2104 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | ||
2105 | return 0; | ||
2106 | if (curr->softirq_context) | ||
2107 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | ||
2108 | return 0; | ||
2109 | } | ||
2110 | } | ||
2111 | if (!hardirqs_off) { | ||
2112 | if (read) { | ||
2113 | if (!mark_lock(curr, hlock, | ||
2114 | LOCK_ENABLED_HARDIRQS_READ)) | ||
2115 | return 0; | ||
2116 | if (curr->softirqs_enabled) | ||
2117 | if (!mark_lock(curr, hlock, | ||
2118 | LOCK_ENABLED_SOFTIRQS_READ)) | ||
2119 | return 0; | ||
2120 | } else { | ||
2121 | if (!mark_lock(curr, hlock, | ||
2122 | LOCK_ENABLED_HARDIRQS)) | ||
2123 | return 0; | ||
2124 | if (curr->softirqs_enabled) | ||
2125 | if (!mark_lock(curr, hlock, | ||
2126 | LOCK_ENABLED_SOFTIRQS)) | ||
2127 | return 0; | ||
2128 | } | ||
2129 | } | ||
2130 | #endif | ||
2131 | /* mark it as used: */ | 2278 | /* mark it as used: */ |
2132 | if (!mark_lock(curr, hlock, LOCK_USED)) | 2279 | if (!mark_lock(curr, hlock, LOCK_USED)) |
2133 | return 0; | 2280 | return 0; |
2134 | out_calc_hash: | 2281 | |
2135 | /* | 2282 | /* |
2136 | * Calculate the chain hash: it's the combined has of all the | 2283 | * Calculate the chain hash: it's the combined has of all the |
2137 | * lock keys along the dependency chain. We save the hash value | 2284 | * lock keys along the dependency chain. We save the hash value |
@@ -2154,77 +2301,15 @@ out_calc_hash: | |||
2154 | } | 2301 | } |
2155 | 2302 | ||
2156 | hlock->prev_chain_key = chain_key; | 2303 | hlock->prev_chain_key = chain_key; |
2157 | 2304 | if (separate_irq_context(curr, hlock)) { | |
2158 | #ifdef CONFIG_TRACE_IRQFLAGS | 2305 | chain_key = 0; |
2159 | /* | 2306 | chain_head = 1; |
2160 | * Keep track of points where we cross into an interrupt context: | ||
2161 | */ | ||
2162 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | ||
2163 | curr->softirq_context; | ||
2164 | if (depth) { | ||
2165 | struct held_lock *prev_hlock; | ||
2166 | |||
2167 | prev_hlock = curr->held_locks + depth-1; | ||
2168 | /* | ||
2169 | * If we cross into another context, reset the | ||
2170 | * hash key (this also prevents the checking and the | ||
2171 | * adding of the dependency to 'prev'): | ||
2172 | */ | ||
2173 | if (prev_hlock->irq_context != hlock->irq_context) { | ||
2174 | chain_key = 0; | ||
2175 | chain_head = 1; | ||
2176 | } | ||
2177 | } | 2307 | } |
2178 | #endif | ||
2179 | chain_key = iterate_chain_key(chain_key, id); | 2308 | chain_key = iterate_chain_key(chain_key, id); |
2180 | curr->curr_chain_key = chain_key; | 2309 | curr->curr_chain_key = chain_key; |
2181 | 2310 | ||
2182 | /* | 2311 | if (!validate_chain(curr, lock, hlock, chain_head)) |
2183 | * Trylock needs to maintain the stack of held locks, but it | 2312 | return 0; |
2184 | * does not add new dependencies, because trylock can be done | ||
2185 | * in any order. | ||
2186 | * | ||
2187 | * We look up the chain_key and do the O(N^2) check and update of | ||
2188 | * the dependencies only if this is a new dependency chain. | ||
2189 | * (If lookup_chain_cache() returns with 1 it acquires | ||
2190 | * graph_lock for us) | ||
2191 | */ | ||
2192 | if (!trylock && (check == 2) && lookup_chain_cache(chain_key, class)) { | ||
2193 | /* | ||
2194 | * Check whether last held lock: | ||
2195 | * | ||
2196 | * - is irq-safe, if this lock is irq-unsafe | ||
2197 | * - is softirq-safe, if this lock is hardirq-unsafe | ||
2198 | * | ||
2199 | * And check whether the new lock's dependency graph | ||
2200 | * could lead back to the previous lock. | ||
2201 | * | ||
2202 | * any of these scenarios could lead to a deadlock. If | ||
2203 | * All validations | ||
2204 | */ | ||
2205 | int ret = check_deadlock(curr, hlock, lock, read); | ||
2206 | |||
2207 | if (!ret) | ||
2208 | return 0; | ||
2209 | /* | ||
2210 | * Mark recursive read, as we jump over it when | ||
2211 | * building dependencies (just like we jump over | ||
2212 | * trylock entries): | ||
2213 | */ | ||
2214 | if (ret == 2) | ||
2215 | hlock->read = 2; | ||
2216 | /* | ||
2217 | * Add dependency only if this lock is not the head | ||
2218 | * of the chain, and if it's not a secondary read-lock: | ||
2219 | */ | ||
2220 | if (!chain_head && ret != 2) | ||
2221 | if (!check_prevs_add(curr, hlock)) | ||
2222 | return 0; | ||
2223 | graph_unlock(); | ||
2224 | } else | ||
2225 | /* after lookup_chain_cache(): */ | ||
2226 | if (unlikely(!debug_locks)) | ||
2227 | return 0; | ||
2228 | 2313 | ||
2229 | curr->lockdep_depth++; | 2314 | curr->lockdep_depth++; |
2230 | check_chain_key(curr); | 2315 | check_chain_key(curr); |
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 58f35e586ee3..2fde34127e2e 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c | |||
@@ -271,8 +271,10 @@ static int lockdep_stats_show(struct seq_file *m, void *v) | |||
271 | if (nr_list_entries) | 271 | if (nr_list_entries) |
272 | factor = sum_forward_deps / nr_list_entries; | 272 | factor = sum_forward_deps / nr_list_entries; |
273 | 273 | ||
274 | #ifdef CONFIG_PROVE_LOCKING | ||
274 | seq_printf(m, " dependency chains: %11lu [max: %lu]\n", | 275 | seq_printf(m, " dependency chains: %11lu [max: %lu]\n", |
275 | nr_lock_chains, MAX_LOCKDEP_CHAINS); | 276 | nr_lock_chains, MAX_LOCKDEP_CHAINS); |
277 | #endif | ||
276 | 278 | ||
277 | #ifdef CONFIG_TRACE_IRQFLAGS | 279 | #ifdef CONFIG_TRACE_IRQFLAGS |
278 | seq_printf(m, " in-hardirq chains: %11u\n", | 280 | seq_printf(m, " in-hardirq chains: %11u\n", |