X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Flockdep.c;h=8bbeef996c76598b7e45e3b48186fc18c03b5be0;hb=a0aea57786fe9c6b62b1a4f28409582520fa494f;hp=000d53a2da32dec690e6b4abccd949cffe831a3a;hpb=9d3651a23dc1f7ed7d207f9118459d3a73d485a7;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 000d53a..8bbeef9 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -41,11 +41,15 @@ #include #include #include +#include #include #include "lockdep_internals.h" +#define CREATE_TRACE_POINTS +#include + #ifdef CONFIG_PROVE_LOCKING int prove_locking = 1; module_param(prove_locking, int, 0644); @@ -432,27 +436,17 @@ atomic_t nr_find_usage_forwards_checks; atomic_t nr_find_usage_forwards_recursions; atomic_t nr_find_usage_backwards_checks; atomic_t nr_find_usage_backwards_recursions; -# define debug_atomic_inc(ptr) atomic_inc(ptr) -# define debug_atomic_dec(ptr) atomic_dec(ptr) -# define debug_atomic_read(ptr) atomic_read(ptr) -#else -# define debug_atomic_inc(ptr) do { } while (0) -# define debug_atomic_dec(ptr) do { } while (0) -# define debug_atomic_read(ptr) 0 #endif /* * Locking printouts: */ -#define __STR(foo) #foo -#define STR(foo) __STR(foo) - #define __USAGE(__STATE) \ - [LOCK_USED_IN_##__STATE] = "IN-"STR(__STATE)"-W", \ - [LOCK_ENABLED_##__STATE] = STR(__STATE)"-ON-W", \ - [LOCK_USED_IN_##__STATE##_READ] = "IN-"STR(__STATE)"-R", \ - [LOCK_ENABLED_##__STATE##_READ] = STR(__STATE)"-ON-R", + [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ + [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ + [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ + [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", static const char *usage_str[] = { @@ -467,62 +461,45 @@ const char * __get_key_name(struct lockdep_subclass_key *key, char *str) return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); } -void -get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, - char *c4, char *c5, char *c6) +static inline unsigned long lock_flag(enum lock_usage_bit bit) { - *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.', *c5 = '.', *c6 = '.'; - - if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) - *c1 = '+'; - else - if (class->usage_mask & LOCKF_ENABLED_HARDIRQ) - *c1 = '-'; + return 1UL << bit; +} - if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) - *c2 = '+'; - else - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ) - *c2 = '-'; +static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) +{ + char c = '.'; - if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) - *c3 = '-'; - if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { - *c3 = '+'; - if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) - *c3 = '?'; + if (class->usage_mask & lock_flag(bit + 2)) + c = '+'; + if (class->usage_mask & lock_flag(bit)) { + c = '-'; + if (class->usage_mask & lock_flag(bit + 2)) + c = '?'; } - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) - *c4 = '-'; - if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { - *c4 = '+'; - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) - *c4 = '?'; - } + return c; +} - if (class->usage_mask & LOCKF_USED_IN_RECLAIM_FS) - *c5 = '+'; - else - if (class->usage_mask & LOCKF_ENABLED_RECLAIM_FS) - *c5 = '-'; +void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) +{ + int i = 0; - if (class->usage_mask & LOCKF_ENABLED_RECLAIM_FS_READ) - *c6 = '-'; - if (class->usage_mask & LOCKF_USED_IN_RECLAIM_FS_READ) { - *c6 = '+'; - if (class->usage_mask & LOCKF_ENABLED_RECLAIM_FS_READ) - *c6 = '?'; - } +#define LOCKDEP_STATE(__STATE) \ + usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ + usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); +#include "lockdep_states.h" +#undef LOCKDEP_STATE + usage[i] = '\0'; } static void print_lock_name(struct lock_class *class) { - char str[KSYM_NAME_LEN], c1, c2, c3, c4, c5, c6; + char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; const char *name; - get_usage_chars(class, &c1, &c2, &c3, &c4, &c5, &c6); + get_usage_chars(class, usage); name = class->name; if (!name) { @@ -535,7 +512,7 @@ static void print_lock_name(struct lock_class *class) if (class->subclass) printk("/%d", class->subclass); } - printk("){%c%c%c%c%c%c}", c1, c2, c3, c4, c5, c6); + printk("){%s}", usage); } static void print_lockdep_cache(struct lockdep_map *lock) @@ -818,6 +795,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); printk("turning off the locking correctness validator.\n"); + dump_stack(); return NULL; } class = lock_classes + nr_lock_classes++; @@ -881,6 +859,7 @@ static struct lock_list *alloc_list_entry(void) printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); printk("turning off the locking correctness validator.\n"); + dump_stack(); return NULL; } return list_entries + nr_list_entries++; @@ -1285,68 +1264,84 @@ check_usage(struct task_struct *curr, struct held_lock *prev, bit_backwards, bit_forwards, irqclass); } -static int -check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, - struct held_lock *next) +static const char *state_names[] = { +#define LOCKDEP_STATE(__STATE) \ + __stringify(__STATE), +#include "lockdep_states.h" +#undef LOCKDEP_STATE +}; + +static const char *state_rnames[] = { +#define LOCKDEP_STATE(__STATE) \ + __stringify(__STATE)"-READ", +#include "lockdep_states.h" +#undef LOCKDEP_STATE +}; + +static inline const char *state_name(enum lock_usage_bit bit) { - /* - * Prove that the new dependency does not connect a hardirq-safe - * lock with a hardirq-unsafe lock - to achieve this we search - * the backwards-subgraph starting at , and the - * forwards-subgraph starting at : - */ - if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, - LOCK_ENABLED_HARDIRQ, "hard")) - return 0; + return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; +} +static int exclusive_bit(int new_bit) +{ /* - * Prove that the new dependency does not connect a hardirq-safe-read - * lock with a hardirq-unsafe lock - to achieve this we search - * the backwards-subgraph starting at , and the - * forwards-subgraph starting at : + * USED_IN + * USED_IN_READ + * ENABLED + * ENABLED_READ + * + * bit 0 - write/read + * bit 1 - used_in/enabled + * bit 2+ state */ - if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, - LOCK_ENABLED_HARDIRQ, "hard-read")) - return 0; + + int state = new_bit & ~3; + int dir = new_bit & 2; /* - * Prove that the new dependency does not connect a softirq-safe - * lock with a softirq-unsafe lock - to achieve this we search - * the backwards-subgraph starting at , and the - * forwards-subgraph starting at : + * keep state, bit flip the direction and strip read. */ - if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, - LOCK_ENABLED_SOFTIRQ, "soft")) - return 0; + return state | (dir ^ 2); +} + +static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, + struct held_lock *next, enum lock_usage_bit bit) +{ /* - * Prove that the new dependency does not connect a softirq-safe-read - * lock with a softirq-unsafe lock - to achieve this we search + * Prove that the new dependency does not connect a hardirq-safe + * lock with a hardirq-unsafe lock - to achieve this we search * the backwards-subgraph starting at , and the * forwards-subgraph starting at : */ - if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, - LOCK_ENABLED_SOFTIRQ, "soft")) + if (!check_usage(curr, prev, next, bit, + exclusive_bit(bit), state_name(bit))) return 0; + bit++; /* _READ */ + /* - * Prove that the new dependency does not connect a reclaim-fs-safe - * lock with a reclaim-fs-unsafe lock - to achieve this we search + * Prove that the new dependency does not connect a hardirq-safe-read + * lock with a hardirq-unsafe lock - to achieve this we search * the backwards-subgraph starting at , and the * forwards-subgraph starting at : */ - if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS, - LOCK_ENABLED_RECLAIM_FS, "reclaim-fs")) + if (!check_usage(curr, prev, next, bit, + exclusive_bit(bit), state_name(bit))) return 0; - /* - * Prove that the new dependency does not connect a reclaim-fs-safe-read - * lock with a reclaim-fs-unsafe lock - to achieve this we search - * the backwards-subgraph starting at , and the - * forwards-subgraph starting at : - */ - if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS_READ, - LOCK_ENABLED_RECLAIM_FS, "reclaim-fs-read")) + return 1; +} + +static int +check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, + struct held_lock *next) +{ +#define LOCKDEP_STATE(__STATE) \ + if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ return 0; +#include "lockdep_states.h" +#undef LOCKDEP_STATE return 1; } @@ -1691,6 +1686,7 @@ cache_hit: printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); printk("turning off the locking correctness validator.\n"); + dump_stack(); return 0; } chain = lock_chains + nr_lock_chains++; @@ -1903,9 +1899,9 @@ print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, curr->comm, task_pid_nr(curr)); print_lock(this); if (forwards) - printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass); + printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); else - printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass); + printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); print_lock_name(other); printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); @@ -2001,30 +1997,6 @@ static int RECLAIM_FS_verbose(struct lock_class *class) #define STRICT_READ_CHECKS 1 -static const char *state_names[] = { -#define LOCKDEP_STATE(__STATE) \ - STR(__STATE), -#include "lockdep_states.h" -#undef LOCKDEP_STATE -}; - -static inline const char *state_name(enum lock_usage_bit bit) -{ - return state_names[bit >> 2]; -} - -static const char *state_rnames[] = { -#define LOCKDEP_STATE(__STATE) \ - STR(__STATE)"-READ", -#include "lockdep_states.h" -#undef LOCKDEP_STATE -}; - -static inline const char *state_rname(enum lock_usage_bit bit) -{ - return state_rnames[bit >> 2]; -} - static int (*state_verbose_f[])(struct lock_class *class) = { #define LOCKDEP_STATE(__STATE) \ __STATE##_verbose, @@ -2038,54 +2010,54 @@ static inline int state_verbose(enum lock_usage_bit bit, return state_verbose_f[bit >> 2](class); } -static int exclusive_bit(int new_bit) -{ - /* - * USED_IN - * USED_IN_READ - * ENABLED - * ENABLED_READ - * - * bit 0 - write/read - * bit 1 - used_in/enabled - * bit 2+ state - */ - - int state = new_bit & ~3; - int dir = new_bit & 2; - - return state | (dir ^ 2); -} - typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, enum lock_usage_bit bit, const char *name); static int -mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit) +mark_lock_irq(struct task_struct *curr, struct held_lock *this, + enum lock_usage_bit new_bit) { - const char *name = state_name(new_bit); - const char *rname = state_rname(new_bit); - int excl_bit = exclusive_bit(new_bit); int read = new_bit & 1; int dir = new_bit & 2; + /* + * mark USED_IN has to look forwards -- to ensure no dependency + * has ENABLED state, which would allow recursion deadlocks. + * + * mark ENABLED has to look backwards -- to ensure no dependee + * has USED_IN state, which, again, would allow recursion deadlocks. + */ check_usage_f usage = dir ? check_usage_backwards : check_usage_forwards; + /* + * Validate that this particular lock does not have conflicting + * usage states. + */ if (!valid_state(curr, this, new_bit, excl_bit)) return 0; - if (!read && !valid_state(curr, this, new_bit, excl_bit + 1)) + /* + * Validate that the lock dependencies don't have conflicting usage + * states. + */ + if ((!read || !dir || STRICT_READ_CHECKS) && + !usage(curr, this, excl_bit, state_name(new_bit & ~1))) return 0; - if ((!read || (!dir || STRICT_READ_CHECKS)) && - !usage(curr, this, excl_bit, name)) - return 0; + /* + * Check for read in write conflicts + */ + if (!read) { + if (!valid_state(curr, this, new_bit, excl_bit + 1)) + return 0; - if ((!read && STRICT_READ_CHECKS) && - !usage(curr, this, excl_bit + 1, rname)) - return 0; + if (STRICT_READ_CHECKS && + !usage(curr, this, excl_bit + 1, + state_name(new_bit + 1))) + return 0; + } if (state_verbose(new_bit, hlock_class(this))) return 2; @@ -2099,14 +2071,6 @@ enum mark_type { #undef LOCKDEP_STATE }; -#define MARK_HELD_CASE(__STATE) \ - case __STATE: \ - if (hlock->read) \ - usage_bit = LOCK_ENABLED_##__STATE##_READ; \ - else \ - usage_bit = LOCK_ENABLED_##__STATE; \ - break; - /* * Mark all held locks with a usage bit: */ @@ -2120,13 +2084,11 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark) for (i = 0; i < curr->lockdep_depth; i++) { hlock = curr->held_locks + i; - switch (mark) { -#define LOCKDEP_STATE(__STATE) MARK_HELD_CASE(__STATE) -#include "lockdep_states.h" -#undef LOCKDEP_STATE - default: - BUG(); - } + usage_bit = 2 + (mark << 2); /* ENABLED */ + if (hlock->read) + usage_bit += 1; /* READ */ + + BUG_ON(usage_bit >= LOCK_USAGE_STATES); if (!mark_lock(curr, hlock, usage_bit)) return 0; @@ -2298,7 +2260,7 @@ void trace_softirqs_off(unsigned long ip) debug_atomic_inc(&redundant_softirqs_off); } -void lockdep_trace_alloc(gfp_t gfp_mask) +static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) { struct task_struct *curr = current; @@ -2317,12 +2279,29 @@ void lockdep_trace_alloc(gfp_t gfp_mask) if (!(gfp_mask & __GFP_FS)) return; - if (DEBUG_LOCKS_WARN_ON(irqs_disabled())) + if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) return; mark_held_locks(curr, RECLAIM_FS); } +static void check_flags(unsigned long flags); + +void lockdep_trace_alloc(gfp_t gfp_mask) +{ + unsigned long flags; + + if (unlikely(current->lockdep_recursion)) + return; + + raw_local_irq_save(flags); + check_flags(flags); + current->lockdep_recursion = 1; + __lockdep_trace_alloc(gfp_mask, flags); + current->lockdep_recursion = 0; + raw_local_irq_restore(flags); +} + static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) { /* @@ -2434,6 +2413,10 @@ static inline int separate_irq_context(struct task_struct *curr, return 0; } +void lockdep_trace_alloc(gfp_t gfp_mask) +{ +} + #endif /* @@ -2509,13 +2492,20 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, void lockdep_init_map(struct lockdep_map *lock, const char *name, struct lock_class_key *key, int subclass) { - if (unlikely(!debug_locks)) + lock->class_cache = NULL; +#ifdef CONFIG_LOCK_STAT + lock->cpu = raw_smp_processor_id(); +#endif + + if (DEBUG_LOCKS_WARN_ON(!name)) { + lock->name = "NULL"; return; + } + + lock->name = name; if (DEBUG_LOCKS_WARN_ON(!key)) return; - if (DEBUG_LOCKS_WARN_ON(!name)) - return; /* * Sanity check, the lock-class key must be persistent: */ @@ -2524,12 +2514,11 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name, DEBUG_LOCKS_WARN_ON(1); return; } - lock->name = name; lock->key = key; - lock->class_cache = NULL; -#ifdef CONFIG_LOCK_STAT - lock->cpu = raw_smp_processor_id(); -#endif + + if (unlikely(!debug_locks)) + return; + if (subclass) register_lock_class(lock, subclass, 1); } @@ -2563,6 +2552,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, debug_locks_off(); printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); printk("turning off the locking correctness validator.\n"); + dump_stack(); return 0; } @@ -2659,6 +2649,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, debug_locks_off(); printk("BUG: MAX_LOCK_DEPTH too low!\n"); printk("turning off the locking correctness validator.\n"); + dump_stack(); return 0; } @@ -2956,6 +2947,8 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, { unsigned long flags; + trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); + if (unlikely(current->lockdep_recursion)) return; @@ -2975,6 +2968,8 @@ void lock_release(struct lockdep_map *lock, int nested, { unsigned long flags; + trace_lock_release(lock, nested, ip); + if (unlikely(current->lockdep_recursion)) return; @@ -3108,6 +3103,8 @@ found_it: hlock->holdtime_stamp = now; } + trace_lock_acquired(lock, ip, waittime); + stats = get_lock_stats(hlock_class(hlock)); if (waittime) { if (hlock->read) @@ -3127,6 +3124,8 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip) { unsigned long flags; + trace_lock_contended(lock, ip); + if (unlikely(!lock_stat)) return;