X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Flockdep.c;h=2594e1ce41cbf12889b44deb3fc202c0a5c30fa2;hb=449cedf099b23a250e7d61982e35555ccb871182;hp=1cedb00e3e7a9d664165af50c8c1f7d5574d5265;hpb=af012961450949ea297b209e091bd1a3805b8a0a;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 1cedb00..2594e1c 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -43,13 +43,14 @@ #include #include #include +#include #include #include "lockdep_internals.h" #define CREATE_TRACE_POINTS -#include +#include #ifdef CONFIG_PROVE_LOCKING int prove_locking = 1; @@ -73,11 +74,11 @@ module_param(lock_stat, int, 0644); * to use a raw spinlock - we really dont want the spinlock * code to recurse back into the lockdep code... */ -static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; +static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; static int graph_lock(void) { - __raw_spin_lock(&lockdep_lock); + arch_spin_lock(&lockdep_lock); /* * Make sure that if another CPU detected a bug while * walking the graph we dont change it (while the other @@ -85,7 +86,7 @@ static int graph_lock(void) * dropped already) */ if (!debug_locks) { - __raw_spin_unlock(&lockdep_lock); + arch_spin_unlock(&lockdep_lock); return 0; } /* prevent any recursions within lockdep from causing deadlocks */ @@ -95,11 +96,11 @@ static int graph_lock(void) static inline int graph_unlock(void) { - if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) + if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) return DEBUG_LOCKS_WARN_ON(1); current->lockdep_recursion--; - __raw_spin_unlock(&lockdep_lock); + arch_spin_unlock(&lockdep_lock); return 0; } @@ -111,7 +112,7 @@ static inline int debug_locks_off_graph_unlock(void) { int ret = debug_locks_off(); - __raw_spin_unlock(&lockdep_lock); + arch_spin_unlock(&lockdep_lock); return ret; } @@ -140,7 +141,13 @@ static inline struct lock_class *hlock_class(struct held_lock *hlock) } #ifdef CONFIG_LOCK_STAT -static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); +static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], + cpu_lock_stats); + +static inline u64 lockstat_clock(void) +{ + return cpu_clock(smp_processor_id()); +} static int lock_point(unsigned long points[], unsigned long ip) { @@ -158,12 +165,12 @@ static int lock_point(unsigned long points[], unsigned long ip) return i; } -static void lock_time_inc(struct lock_time *lt, s64 time) +static void lock_time_inc(struct lock_time *lt, u64 time) { if (time > lt->max) lt->max = time; - if (time < lt->min || !lt->min) + if (time < lt->min || !lt->nr) lt->min = time; lt->total += time; @@ -172,8 +179,15 @@ static void lock_time_inc(struct lock_time *lt, s64 time) static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) { - dst->min += src->min; - dst->max += src->max; + if (!src->nr) + return; + + if (src->max > dst->max) + dst->max = src->max; + + if (src->min < dst->min || !dst->nr) + dst->min = src->min; + dst->total += src->total; dst->nr += src->nr; } @@ -186,7 +200,7 @@ struct lock_class_stats lock_stats(struct lock_class *class) memset(&stats, 0, sizeof(struct lock_class_stats)); for_each_possible_cpu(cpu) { struct lock_class_stats *pcs = - &per_cpu(lock_stats, cpu)[class - lock_classes]; + &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) stats.contention_point[i] += pcs->contention_point[i]; @@ -213,7 +227,7 @@ void clear_lock_stats(struct lock_class *class) for_each_possible_cpu(cpu) { struct lock_class_stats *cpu_stats = - &per_cpu(lock_stats, cpu)[class - lock_classes]; + &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; memset(cpu_stats, 0, sizeof(struct lock_class_stats)); } @@ -223,23 +237,23 @@ void clear_lock_stats(struct lock_class *class) static struct lock_class_stats *get_lock_stats(struct lock_class *class) { - return &get_cpu_var(lock_stats)[class - lock_classes]; + return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; } static void put_lock_stats(struct lock_class_stats *stats) { - put_cpu_var(lock_stats); + put_cpu_var(cpu_lock_stats); } static void lock_release_holdtime(struct held_lock *hlock) { struct lock_class_stats *stats; - s64 holdtime; + u64 holdtime; if (!lock_stat) return; - holdtime = sched_clock() - hlock->holdtime_stamp; + holdtime = lockstat_clock() - hlock->holdtime_stamp; stats = get_lock_stats(hlock_class(hlock)); if (hlock->read) @@ -367,11 +381,22 @@ static int save_trace(struct stack_trace *trace) save_stack_trace(trace); + /* + * Some daft arches put -1 at the end to indicate its a full trace. + * + * this is buggy anyway, since it takes a whole extra entry so a + * complete trace that maxes out the entries provided will be reported + * as incomplete, friggin useless + */ + if (trace->nr_entries != 0 && + trace->entries[trace->nr_entries-1] == ULONG_MAX) + trace->nr_entries--; + trace->max_entries = trace->nr_entries; nr_stack_trace_entries += trace->nr_entries; - if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { + if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { if (!debug_locks_off_graph_unlock()) return 0; @@ -389,7 +414,6 @@ unsigned int nr_hardirq_chains; unsigned int nr_softirq_chains; unsigned int nr_process_chains; unsigned int max_lockdep_depth; -unsigned int max_recursion_depth; #ifdef CONFIG_DEBUG_LOCKDEP /* @@ -419,11 +443,8 @@ atomic_t redundant_softirqs_on; atomic_t redundant_softirqs_off; atomic_t nr_unused_locks; atomic_t nr_cyclic_checks; -atomic_t nr_cyclic_check_recursions; 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; #endif /* @@ -562,9 +583,6 @@ static int static_obj(void *obj) unsigned long start = (unsigned long) &_stext, end = (unsigned long) &_end, addr = (unsigned long) obj; -#ifdef CONFIG_SMP - int i; -#endif /* * static variable? @@ -572,24 +590,19 @@ static int static_obj(void *obj) if ((addr >= start) && (addr < end)) return 1; -#ifdef CONFIG_SMP + if (arch_is_kernel_data(addr)) + return 1; + /* - * percpu var? + * in-kernel percpu var? */ - for_each_possible_cpu(i) { - start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); - end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM - + per_cpu_offset(i); - - if ((addr >= start) && (addr < end)) - return 1; - } -#endif + if (is_kernel_percpu_address(addr)) + return 1; /* - * module var? + * module static or percpu var? */ - return is_module_address(addr); + return is_module_address(addr) || is_module_percpu_address(addr); } /* @@ -833,29 +846,33 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this, return 1; } -/*For good efficiency of modular, we use power of 2*/ +/* + * For good efficiency of modular, we use power of 2 + */ #define MAX_CIRCULAR_QUEUE_SIZE 4096UL #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) -/* The circular_queue and helpers is used to implement the +/* + * The circular_queue and helpers is used to implement the * breadth-first search(BFS)algorithem, by which we can build * the shortest path from the next lock to be acquired to the * previous held lock if there is a circular between them. - * */ + */ struct circular_queue { unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; unsigned int front, rear; }; static struct circular_queue lock_cq; -static unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)]; unsigned int max_bfs_queue_depth; +static unsigned int lockdep_dependency_gen_id; + static inline void __cq_init(struct circular_queue *cq) { cq->front = cq->rear = 0; - bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES); + lockdep_dependency_gen_id++; } static inline int __cq_empty(struct circular_queue *cq) @@ -897,18 +914,20 @@ static inline void mark_lock_accessed(struct lock_list *lock, struct lock_list *parent) { unsigned long nr; + nr = lock - list_entries; WARN_ON(nr >= nr_list_entries); lock->parent = parent; - set_bit(nr, bfs_accessed); + lock->class->dep_gen_id = lockdep_dependency_gen_id; } static inline unsigned long lock_accessed(struct lock_list *lock) { unsigned long nr; + nr = lock - list_entries; WARN_ON(nr >= nr_list_entries); - return test_bit(nr, bfs_accessed); + return lock->class->dep_gen_id == lockdep_dependency_gen_id; } static inline struct lock_list *get_lock_parent(struct lock_list *child) @@ -1141,9 +1160,9 @@ unsigned long lockdep_count_forward_deps(struct lock_class *class) this.class = class; local_irq_save(flags); - __raw_spin_lock(&lockdep_lock); + arch_spin_lock(&lockdep_lock); ret = __lockdep_count_forward_deps(&this); - __raw_spin_unlock(&lockdep_lock); + arch_spin_unlock(&lockdep_lock); local_irq_restore(flags); return ret; @@ -1168,9 +1187,9 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class) this.class = class; local_irq_save(flags); - __raw_spin_lock(&lockdep_lock); + arch_spin_lock(&lockdep_lock); ret = __lockdep_count_backward_deps(&this); - __raw_spin_unlock(&lockdep_lock); + arch_spin_unlock(&lockdep_lock); local_irq_restore(flags); return ret; @@ -2118,7 +2137,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this, return ret; return print_irq_inversion_bug(curr, &root, target_entry, - this, 1, irqclass); + this, 0, irqclass); } void print_irqtrace_events(struct task_struct *curr) @@ -2693,13 +2712,15 @@ EXPORT_SYMBOL_GPL(lockdep_init_map); */ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, int trylock, int read, int check, int hardirqs_off, - struct lockdep_map *nest_lock, unsigned long ip) + struct lockdep_map *nest_lock, unsigned long ip, + int references) { struct task_struct *curr = current; struct lock_class *class = NULL; struct held_lock *hlock; unsigned int depth, id; int chain_head = 0; + int class_idx; u64 chain_key; if (!prove_locking) @@ -2747,10 +2768,24 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) return 0; + class_idx = class - lock_classes + 1; + + if (depth) { + hlock = curr->held_locks + depth - 1; + if (hlock->class_idx == class_idx && nest_lock) { + if (hlock->references) + hlock->references++; + else + hlock->references = 2; + + return 1; + } + } + hlock = curr->held_locks + depth; if (DEBUG_LOCKS_WARN_ON(!class)) return 0; - hlock->class_idx = class - lock_classes + 1; + hlock->class_idx = class_idx; hlock->acquire_ip = ip; hlock->instance = lock; hlock->nest_lock = nest_lock; @@ -2758,9 +2793,10 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, hlock->read = read; hlock->check = check; hlock->hardirqs_off = !!hardirqs_off; + hlock->references = references; #ifdef CONFIG_LOCK_STAT hlock->waittime_stamp = 0; - hlock->holdtime_stamp = sched_clock(); + hlock->holdtime_stamp = lockstat_clock(); #endif if (check == 2 && !mark_irqflags(curr, hlock)) @@ -2866,6 +2902,30 @@ static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, return 1; } +static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) +{ + if (hlock->instance == lock) + return 1; + + if (hlock->references) { + struct lock_class *class = lock->class_cache; + + if (!class) + class = look_up_lock_class(lock, 0); + + if (DEBUG_LOCKS_WARN_ON(!class)) + return 0; + + if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) + return 0; + + if (hlock->class_idx == class - lock_classes + 1) + return 1; + } + + return 0; +} + static int __lock_set_class(struct lockdep_map *lock, const char *name, struct lock_class_key *key, unsigned int subclass, @@ -2889,7 +2949,7 @@ __lock_set_class(struct lockdep_map *lock, const char *name, */ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) break; - if (hlock->instance == lock) + if (match_held_lock(hlock, lock)) goto found_it; prev_hlock = hlock; } @@ -2908,7 +2968,8 @@ found_it: if (!__lock_acquire(hlock->instance, hlock_class(hlock)->subclass, hlock->trylock, hlock->read, hlock->check, hlock->hardirqs_off, - hlock->nest_lock, hlock->acquire_ip)) + hlock->nest_lock, hlock->acquire_ip, + hlock->references)) return 0; } @@ -2947,20 +3008,34 @@ lock_release_non_nested(struct task_struct *curr, */ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) break; - if (hlock->instance == lock) + if (match_held_lock(hlock, lock)) goto found_it; prev_hlock = hlock; } return print_unlock_inbalance_bug(curr, lock, ip); found_it: - lock_release_holdtime(hlock); + if (hlock->instance == lock) + lock_release_holdtime(hlock); + + if (hlock->references) { + hlock->references--; + if (hlock->references) { + /* + * We had, and after removing one, still have + * references, the current lock stack is still + * valid. We're done! + */ + return 1; + } + } /* * We have the right lock to unlock, 'hlock' points to it. * Now we remove it from the stack, and add back the other * entries (if any), recalculating the hash along the way: */ + curr->lockdep_depth = i; curr->curr_chain_key = hlock->prev_chain_key; @@ -2969,7 +3044,8 @@ found_it: if (!__lock_acquire(hlock->instance, hlock_class(hlock)->subclass, hlock->trylock, hlock->read, hlock->check, hlock->hardirqs_off, - hlock->nest_lock, hlock->acquire_ip)) + hlock->nest_lock, hlock->acquire_ip, + hlock->references)) return 0; } @@ -2999,7 +3075,7 @@ static int lock_release_nested(struct task_struct *curr, /* * Is the unlock non-nested: */ - if (hlock->instance != lock) + if (hlock->instance != lock || hlock->references) return lock_release_non_nested(curr, lock, ip); curr->lockdep_depth--; @@ -3044,6 +3120,21 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) check_chain_key(curr); } +static int __lock_is_held(struct lockdep_map *lock) +{ + struct task_struct *curr = current; + int i; + + for (i = 0; i < curr->lockdep_depth; i++) { + struct held_lock *hlock = curr->held_locks + i; + + if (match_held_lock(hlock, lock)) + return 1; + } + + return 0; +} + /* * Check whether we follow the irq-flags state precisely: */ @@ -3110,8 +3201,6 @@ 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; @@ -3119,8 +3208,9 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, check_flags(flags); current->lockdep_recursion = 1; + trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); __lock_acquire(lock, subclass, trylock, read, check, - irqs_disabled_flags(flags), nest_lock, ip); + irqs_disabled_flags(flags), nest_lock, ip, 0); current->lockdep_recursion = 0; raw_local_irq_restore(flags); } @@ -3131,20 +3221,39 @@ void lock_release(struct lockdep_map *lock, int nested, { unsigned long flags; - trace_lock_release(lock, nested, ip); - if (unlikely(current->lockdep_recursion)) return; raw_local_irq_save(flags); check_flags(flags); current->lockdep_recursion = 1; + trace_lock_release(lock, nested, ip); __lock_release(lock, nested, ip); current->lockdep_recursion = 0; raw_local_irq_restore(flags); } EXPORT_SYMBOL_GPL(lock_release); +int lock_is_held(struct lockdep_map *lock) +{ + unsigned long flags; + int ret = 0; + + if (unlikely(current->lockdep_recursion)) + return ret; + + raw_local_irq_save(flags); + check_flags(flags); + + current->lockdep_recursion = 1; + ret = __lock_is_held(lock); + current->lockdep_recursion = 0; + raw_local_irq_restore(flags); + + return ret; +} +EXPORT_SYMBOL_GPL(lock_is_held); + void lockdep_set_current_reclaim_state(gfp_t gfp_mask) { current->lockdep_reclaim_gfp = gfp_mask; @@ -3204,7 +3313,7 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip) */ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) break; - if (hlock->instance == lock) + if (match_held_lock(hlock, lock)) goto found_it; prev_hlock = hlock; } @@ -3212,7 +3321,10 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip) return; found_it: - hlock->waittime_stamp = sched_clock(); + if (hlock->instance != lock) + return; + + hlock->waittime_stamp = lockstat_clock(); contention_point = lock_point(hlock_class(hlock)->contention_point, ip); contending_point = lock_point(hlock_class(hlock)->contending_point, @@ -3235,8 +3347,7 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip) struct held_lock *hlock, *prev_hlock; struct lock_class_stats *stats; unsigned int depth; - u64 now; - s64 waittime = 0; + u64 now, waittime = 0; int i, cpu; depth = curr->lockdep_depth; @@ -3251,7 +3362,7 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip) */ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) break; - if (hlock->instance == lock) + if (match_held_lock(hlock, lock)) goto found_it; prev_hlock = hlock; } @@ -3259,9 +3370,12 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip) return; found_it: + if (hlock->instance != lock) + return; + cpu = smp_processor_id(); if (hlock->waittime_stamp) { - now = sched_clock(); + now = lockstat_clock(); waittime = now - hlock->waittime_stamp; hlock->holdtime_stamp = now; } @@ -3287,8 +3401,6 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip) { unsigned long flags; - trace_lock_contended(lock, ip); - if (unlikely(!lock_stat)) return; @@ -3298,6 +3410,7 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip) raw_local_irq_save(flags); check_flags(flags); current->lockdep_recursion = 1; + trace_lock_contended(lock, ip); __lock_contended(lock, ip); current->lockdep_recursion = 0; raw_local_irq_restore(flags); @@ -3489,10 +3602,11 @@ void __init lockdep_info(void) sizeof(struct list_head) * CLASSHASH_SIZE + sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + - sizeof(struct list_head) * CHAINHASH_SIZE) / 1024 + sizeof(struct list_head) * CHAINHASH_SIZE #ifdef CONFIG_PROVE_LOCKING - + sizeof(struct circular_queue) + sizeof(bfs_accessed) + + sizeof(struct circular_queue) #endif + ) / 1024 ); printk(" per task-struct memory footprint: %lu bytes\n", @@ -3682,3 +3796,22 @@ void lockdep_sys_exit(void) lockdep_print_held_locks(curr); } } + +void lockdep_rcu_dereference(const char *file, const int line) +{ + struct task_struct *curr = current; + + if (!debug_locks_off()) + return; + printk("\n===================================================\n"); + printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n"); + printk( "---------------------------------------------------\n"); + printk("%s:%d invoked rcu_dereference_check() without protection!\n", + file, line); + printk("\nother info that might help us debug this:\n\n"); + printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks); + lockdep_print_held_locks(curr); + printk("\nstack backtrace:\n"); + dump_stack(); +} +EXPORT_SYMBOL_GPL(lockdep_rcu_dereference);