Commit ef5d4707 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
Browse files

[PATCH] lockdep: prove mutex locking correctness



Use the lock validator framework to prove mutex locking correctness.
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8a25d5de
......@@ -2,6 +2,7 @@
#define __LINUX_MUTEX_DEBUG_H
#include <linux/linkage.h>
#include <linux/lockdep.h>
/*
* Mutexes - debugging helpers:
......@@ -10,7 +11,12 @@
#define __DEBUG_MUTEX_INITIALIZER(lockname) \
, .magic = &lockname
#define mutex_init(sem) __mutex_init(sem, __FILE__":"#sem)
#define mutex_init(mutex) \
do { \
static struct lock_class_key __key; \
\
__mutex_init((mutex), #mutex, &__key); \
} while (0)
extern void FASTCALL(mutex_destroy(struct mutex *lock));
......
......@@ -13,6 +13,7 @@
#include <linux/list.h>
#include <linux/spinlock_types.h>
#include <linux/linkage.h>
#include <linux/lockdep.h>
#include <asm/atomic.h>
......@@ -53,6 +54,9 @@ struct mutex {
const char *name;
void *magic;
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
};
/*
......@@ -72,20 +76,34 @@ struct mutex_waiter {
# include <linux/mutex-debug.h>
#else
# define __DEBUG_MUTEX_INITIALIZER(lockname)
# define mutex_init(mutex) __mutex_init(mutex, NULL)
# define mutex_init(mutex) \
do { \
static struct lock_class_key __key; \
\
__mutex_init((mutex), #mutex, &__key); \
} while (0)
# define mutex_destroy(mutex) do { } while (0)
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
, .dep_map = { .name = #lockname }
#else
# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
#endif
#define __MUTEX_INITIALIZER(lockname) \
{ .count = ATOMIC_INIT(1) \
, .wait_lock = SPIN_LOCK_UNLOCKED \
, .wait_list = LIST_HEAD_INIT(lockname.wait_list) \
__DEBUG_MUTEX_INITIALIZER(lockname) }
__DEBUG_MUTEX_INITIALIZER(lockname) \
__DEP_MAP_MUTEX_INITIALIZER(lockname) }
#define DEFINE_MUTEX(mutexname) \
struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
extern void fastcall __mutex_init(struct mutex *lock, const char *name);
extern void __mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key);
/***
* mutex_is_locked - is the mutex locked
......@@ -104,6 +122,13 @@ static inline int fastcall mutex_is_locked(struct mutex *lock)
*/
extern void fastcall mutex_lock(struct mutex *lock);
extern int fastcall mutex_lock_interruptible(struct mutex *lock);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass);
#else
# define mutex_lock_nested(lock, subclass) mutex_lock(lock)
#endif
/*
* NOTE: mutex_trylock() follows the spin_trylock() convention,
* not the down_trylock() convention!
......
......@@ -83,12 +83,16 @@ void debug_mutex_unlock(struct mutex *lock)
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
}
void debug_mutex_init(struct mutex *lock, const char *name)
void debug_mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key)
{
#ifdef CONFIG_DEBUG_LOCK_ALLOC
/*
* Make sure we are not reinitializing a held lock:
*/
debug_check_no_locks_freed((void *)lock, sizeof(*lock));
lockdep_init_map(&lock->dep_map, name, key);
#endif
lock->owner = NULL;
lock->magic = lock;
}
......
......@@ -39,13 +39,14 @@
*
* It is not allowed to initialize an already locked mutex.
*/
__always_inline void fastcall __mutex_init(struct mutex *lock, const char *name)
void
__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
{
atomic_set(&lock->count, 1);
spin_lock_init(&lock->wait_lock);
INIT_LIST_HEAD(&lock->wait_list);
debug_mutex_init(lock, name);
debug_mutex_init(lock, name, key);
}
EXPORT_SYMBOL(__mutex_init);
......@@ -131,6 +132,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass)
spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_lock_common(lock, &waiter);
mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
debug_mutex_add_waiter(lock, &waiter, task->thread_info);
/* add waiting tasks to the end of the waitqueue (FIFO): */
......@@ -158,6 +160,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass)
if (unlikely(state == TASK_INTERRUPTIBLE &&
signal_pending(task))) {
mutex_remove_waiter(lock, &waiter, task->thread_info);
mutex_release(&lock->dep_map, 1, _RET_IP_);
spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
......@@ -194,16 +197,28 @@ __mutex_lock_slowpath(atomic_t *lock_count)
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0);
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void __sched
mutex_lock_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass);
}
EXPORT_SYMBOL_GPL(mutex_lock_nested);
#endif
/*
* Release the lock, slowpath:
*/
static fastcall inline void
__mutex_unlock_common_slowpath(atomic_t *lock_count)
__mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
unsigned long flags;
spin_lock_mutex(&lock->wait_lock, flags);
mutex_release(&lock->dep_map, nested, _RET_IP_);
debug_mutex_unlock(lock);
/*
......@@ -236,7 +251,7 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count)
static fastcall noinline void
__mutex_unlock_slowpath(atomic_t *lock_count)
{
__mutex_unlock_common_slowpath(lock_count);
__mutex_unlock_common_slowpath(lock_count, 1);
}
/*
......@@ -287,9 +302,10 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
spin_lock_mutex(&lock->wait_lock, flags);
prev = atomic_xchg(&lock->count, -1);
if (likely(prev == 1))
if (likely(prev == 1)) {
debug_mutex_set_owner(lock, current_thread_info());
mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
}
/* Set it back to 0 if there are no waiters: */
if (likely(list_empty(&lock->wait_list)))
atomic_set(&lock->count, 0);
......
......@@ -22,7 +22,7 @@
#define debug_mutex_free_waiter(waiter) do { } while (0)
#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
#define debug_mutex_unlock(lock) do { } while (0)
#define debug_mutex_init(lock, name) do { } while (0)
#define debug_mutex_init(lock, name, key) do { } while (0)
static inline void
debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
......
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