[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>

1 files changed, 12 insertions, 70 deletions

diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h
index bdab13a9ee26..babfbdfc534b 100644
--- a/kernel/mutex-debug.h
+++ b/kernel/mutex-debug.h
@@ -10,102 +10,44 @@
  * More details are in kernel/mutex-debug.c.
  */
 
-extern spinlock_t debug_mutex_lock;
-extern struct list_head debug_mutex_held_locks;
-extern int debug_mutex_on;
-
-/*
- * In the debug case we carry the caller's instruction pointer into
- * other functions, but we dont want the function argument overhead
- * in the nondebug case - hence these macros:
- */
-#define __IP_DECL__		, unsigned long ip
-#define __IP__			, ip
-#define __RET_IP__		, (unsigned long)__builtin_return_address(0)
-
 /*
  * This must be called with lock->wait_lock held.
  */
-extern void debug_mutex_set_owner(struct mutex *lock,
-				  struct thread_info *new_owner __IP_DECL__);
+extern void
+debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner);
 
 static inline void debug_mutex_clear_owner(struct mutex *lock)
 {
 	lock->owner = NULL;
 }
 
-extern void debug_mutex_init_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_lock_common(struct mutex *lock,
+				    struct mutex_waiter *waiter);
 extern void debug_mutex_wake_waiter(struct mutex *lock,
 				    struct mutex_waiter *waiter);
 extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
 extern void debug_mutex_add_waiter(struct mutex *lock,
 				   struct mutex_waiter *waiter,
-				   struct thread_info *ti __IP_DECL__);
+				   struct thread_info *ti);
 extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 				struct thread_info *ti);
 extern void debug_mutex_unlock(struct mutex *lock);
-extern void debug_mutex_init(struct mutex *lock, const char *name);
-
-#define debug_spin_lock_save(lock, flags)		\
-	do {						\
-		local_irq_save(flags);			\
-		if (debug_mutex_on)			\
-			spin_lock(lock);		\
-	} while (0)
-
-#define debug_spin_unlock_restore(lock, flags)		\
-	do {						\
-		if (debug_mutex_on)			\
-			spin_unlock(lock);		\
-		local_irq_restore(flags);		\
-		preempt_check_resched();		\
-	} while (0)
+extern void debug_mutex_init(struct mutex *lock, const char *name,
+			     struct lock_class_key *key);
 
 #define spin_lock_mutex(lock, flags)			\
 	do {						\
 		struct mutex *l = container_of(lock, struct mutex, wait_lock); \
 							\
 		DEBUG_LOCKS_WARN_ON(in_interrupt());	\
-		debug_spin_lock_save(&debug_mutex_lock, flags); \
-		spin_lock(lock);			\
+		local_irq_save(flags);			\
+		__raw_spin_lock(&(lock)->raw_lock);	\
 		DEBUG_LOCKS_WARN_ON(l->magic != l);	\
 	} while (0)
 
 #define spin_unlock_mutex(lock, flags)			\
 	do {						\
-		spin_unlock(lock);			\
-		debug_spin_unlock_restore(&debug_mutex_lock, flags);	\
+		__raw_spin_unlock(&(lock)->raw_lock);	\
+		local_irq_restore(flags);		\
+		preempt_check_resched();		\
 	} while (0)
-
-#define DEBUG_OFF()					\
-do {							\
-	if (debug_mutex_on) {				\
-		debug_mutex_on = 0;			\
-		console_verbose();			\
-		if (spin_is_locked(&debug_mutex_lock))	\
-			spin_unlock(&debug_mutex_lock);	\
-	}						\
-} while (0)
-
-#define DEBUG_BUG()					\
-do {							\
-	if (debug_mutex_on) {				\
-		DEBUG_OFF();				\
-		BUG();					\
-	}						\
-} while (0)
-
-#define DEBUG_LOCKS_WARN_ON(c)				\
-do {							\
-	if (unlikely(c && debug_mutex_on)) {		\
-		DEBUG_OFF();				\
-		WARN_ON(1);				\
-	}						\
-} while (0)
-
-#ifdef CONFIG_SMP
-# define SMP_DEBUG_LOCKS_WARN_ON(c)			DEBUG_LOCKS_WARN_ON(c)
-#else
-# define SMP_DEBUG_LOCKS_WARN_ON(c)			do { } while (0)
-#endif
-