[PATCH] lockdep: better lock debugging
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 <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 101ceeb..3aad0b7 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -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 @@
* 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 @@
*
* 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 @@
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 @@
* 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 @@
/* 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 @@
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 @@
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 =
@@ -237,11 +231,20 @@
}
/*
+ * 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 @@
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 @@
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);