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[PATCH] lockdep: better lock debugging

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Generic lock debugging:

 - generalized lock debugging framework. For example, a bug in one lock
   subsystem turns off debugging in all lock subsystems.

 - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
   the mutex/rtmutex debugging code: it caused way too much prototype
   hackery, and lockdep will give the same information anyway.

 - ability to do silent tests

 - check lock freeing in vfree too.

 - more finegrained debugging options, to allow distributions to
   turn off more expensive debugging features.

There's no separate 'held mutexes' list anymore - but there's a 'held locks'
stack within lockdep, which unifies deadlock detection across all lock
classes.  (this is independent of the lockdep validation stuff - lockdep first
checks whether we are holding a lock already)

Here are the current debugging options:

CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y

which do:

 config DEBUG_MUTEXES
          bool "Mutex debugging, basic checks"

 config DEBUG_LOCK_ALLOC
         bool "Detect incorrect freeing of live mutexes"

Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Arjan van de Ven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Ingo Molnar 2006-07-03 00:24:33 -07:00 • committed by Linus Torvalds
commit 9a11b49a80
25 changed files with 265 additions and 567 deletions
Download patch file Download diff file Expand all files Collapse all files

52
kernel/mutex.c
View file

@ -17,6 +17,7 @@
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
/*
* In the DEBUG case we are using the "NULL fastpath" for mutexes,
@ -38,7 +39,7 @@
*
* It is not allowed to initialize an already locked mutex.
*/
void fastcall __mutex_init(struct mutex *lock, const char *name)
__always_inline void fastcall __mutex_init(struct mutex *lock, const char *name)
{
atomic_set(&lock->count, 1);
spin_lock_init(&lock->wait_lock);
@ -56,7 +57,7 @@ EXPORT_SYMBOL(__mutex_init);
* branch is predicted by the CPU as default-untaken.
*/
static void fastcall noinline __sched
__mutex_lock_slowpath(atomic_t *lock_count __IP_DECL__);
__mutex_lock_slowpath(atomic_t *lock_count);
/***
* mutex_lock - acquire the mutex
@ -79,7 +80,7 @@ __mutex_lock_slowpath(atomic_t *lock_count __IP_DECL__);
*
* This function is similar to (but not equivalent to) down().
*/
void fastcall __sched mutex_lock(struct mutex *lock)
void inline fastcall __sched mutex_lock(struct mutex *lock)
{
might_sleep();
/*
@ -92,7 +93,7 @@ void fastcall __sched mutex_lock(struct mutex *lock)
EXPORT_SYMBOL(mutex_lock);
static void fastcall noinline __sched
__mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__);
__mutex_unlock_slowpath(atomic_t *lock_count);
/***
* mutex_unlock - release the mutex
@ -120,18 +121,17 @@ EXPORT_SYMBOL(mutex_unlock);
* Lock a mutex (possibly interruptible), slowpath:
*/
static inline int __sched
__mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass)
{
struct task_struct *task = current;
struct mutex_waiter waiter;
unsigned int old_val;
unsigned long flags;
debug_mutex_init_waiter(&waiter);
spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_add_waiter(lock, &waiter, task->thread_info, ip);
debug_mutex_lock_common(lock, &waiter);
debug_mutex_add_waiter(lock, &waiter, task->thread_info);
/* add waiting tasks to the end of the waitqueue (FIFO): */
list_add_tail(&waiter.list, &lock->wait_list);
@ -173,7 +173,7 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
/* got the lock - rejoice! */
mutex_remove_waiter(lock, &waiter, task->thread_info);
debug_mutex_set_owner(lock, task->thread_info __IP__);
debug_mutex_set_owner(lock, task->thread_info);
/* set it to 0 if there are no waiters left: */
if (likely(list_empty(&lock->wait_list)))
@ -183,32 +183,28 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
debug_mutex_free_waiter(&waiter);
DEBUG_LOCKS_WARN_ON(list_empty(&lock->held_list));
DEBUG_LOCKS_WARN_ON(lock->owner != task->thread_info);
return 0;
}
static void fastcall noinline __sched
__mutex_lock_slowpath(atomic_t *lock_count __IP_DECL__)
__mutex_lock_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE __IP__);
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0);
}
/*
* Release the lock, slowpath:
*/
static fastcall noinline void
__mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
static fastcall inline void
__mutex_unlock_common_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
unsigned long flags;
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_unlock(lock);
/*
* some architectures leave the lock unlocked in the fastpath failure
@ -218,8 +214,6 @@ __mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
if (__mutex_slowpath_needs_to_unlock())
atomic_set(&lock->count, 1);
debug_mutex_unlock(lock);
if (!list_empty(&lock->wait_list)) {
/* get the first entry from the wait-list: */
struct mutex_waiter *waiter =
@ -236,12 +230,21 @@ __mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
spin_unlock_mutex(&lock->wait_lock, flags);
}
/*
* Release the lock, slowpath:
*/
static fastcall noinline void
__mutex_unlock_slowpath(atomic_t *lock_count)
{
__mutex_unlock_common_slowpath(lock_count);
}
/*
* Here come the less common (and hence less performance-critical) APIs:
* mutex_lock_interruptible() and mutex_trylock().
*/
static int fastcall noinline __sched
__mutex_lock_interruptible_slowpath(atomic_t *lock_count __IP_DECL__);
__mutex_lock_interruptible_slowpath(atomic_t *lock_count);
/***
* mutex_lock_interruptible - acquire the mutex, interruptable
@ -264,11 +267,11 @@ int fastcall __sched mutex_lock_interruptible(struct mutex *lock)
EXPORT_SYMBOL(mutex_lock_interruptible);
static int fastcall noinline __sched
__mutex_lock_interruptible_slowpath(atomic_t *lock_count __IP_DECL__)
__mutex_lock_interruptible_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE __IP__);
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0);
}
/*
@ -285,7 +288,8 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
prev = atomic_xchg(&lock->count, -1);
if (likely(prev == 1))
debug_mutex_set_owner(lock, current_thread_info() __RET_IP__);
debug_mutex_set_owner(lock, current_thread_info());
/* Set it back to 0 if there are no waiters: */
if (likely(list_empty(&lock->wait_list)))
atomic_set(&lock->count, 0);