[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>

drivers/char/sysrq.c

@@ -151,7 +151,7 @@ static struct sysrq_key_op sysrq_mountro_op = {
 static void sysrq_handle_showlocks(int key, struct pt_regs *pt_regs,
 				struct tty_struct *tty)
 {
-	mutex_debug_show_all_locks();
+	debug_show_all_locks();
 }
 static struct sysrq_key_op sysrq_showlocks_op = {
 	.handler	= sysrq_handle_showlocks,

include/asm-generic/mutex-null.h

@@ -10,14 +10,9 @@
 #ifndef _ASM_GENERIC_MUTEX_NULL_H
 #define _ASM_GENERIC_MUTEX_NULL_H
 
-/* extra parameter only needed for mutex debugging: */
+#define __mutex_fastpath_lock(count, fail_fn)		fail_fn(count)
-#ifndef __IP__
+#define __mutex_fastpath_lock_retval(count, fail_fn)	fail_fn(count)
-# define __IP__
+#define __mutex_fastpath_unlock(count, fail_fn)		fail_fn(count)
-#endif
-
-#define __mutex_fastpath_lock(count, fail_fn)	      fail_fn(count __RET_IP__)
-#define __mutex_fastpath_lock_retval(count, fail_fn)  fail_fn(count __RET_IP__)
-#define __mutex_fastpath_unlock(count, fail_fn)       fail_fn(count __RET_IP__)
 #define __mutex_fastpath_trylock(count, fail_fn)	fail_fn(count)
 #define __mutex_slowpath_needs_to_unlock()		1
 

include/linux/debug_locks.h

@@ -0,0 +1,69 @@
+#ifndef __LINUX_DEBUG_LOCKING_H
+#define __LINUX_DEBUG_LOCKING_H
+
+extern int debug_locks;
+extern int debug_locks_silent;
+
+/*
+ * Generic 'turn off all lock debugging' function:
+ */
+extern int debug_locks_off(void);
+
+/*
+ * 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 _RET_IP_		(unsigned long)__builtin_return_address(0)
+#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
+
+#define DEBUG_LOCKS_WARN_ON(c)						\
+({									\
+	int __ret = 0;							\
+									\
+	if (unlikely(c)) {						\
+		if (debug_locks_off())					\
+			WARN_ON(1);					\
+		__ret = 1;						\
+	}								\
+	__ret;								\
+})
+
+#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
+
+#ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS
+  extern void locking_selftest(void);
+#else
+# define locking_selftest()	do { } while (0)
+#endif
+
+#ifdef CONFIG_LOCKDEP
+extern void debug_show_all_locks(void);
+extern void debug_show_held_locks(struct task_struct *task);
+extern void debug_check_no_locks_freed(const void *from, unsigned long len);
+extern void debug_check_no_locks_held(struct task_struct *task);
+#else
+static inline void debug_show_all_locks(void)
+{
+}
+
+static inline void debug_show_held_locks(struct task_struct *task)
+{
+}
+
+static inline void
+debug_check_no_locks_freed(const void *from, unsigned long len)
+{
+}
+
+static inline void
+debug_check_no_locks_held(struct task_struct *task)
+{
+}
+#endif
+
+#endif

include/linux/init_task.h

@@ -124,7 +124,6 @@ extern struct group_info init_groups;
 	.cpu_timers	= INIT_CPU_TIMERS(tsk.cpu_timers),		\
 	.fs_excl	= ATOMIC_INIT(0),				\
 	.pi_lock	= SPIN_LOCK_UNLOCKED,				\
-	INIT_RT_MUTEXES(tsk)						\
 }
 
 

include/linux/mm.h

@@ -14,6 +14,7 @@
 #include <linux/prio_tree.h>
 #include <linux/fs.h>
 #include <linux/mutex.h>
+#include <linux/debug_locks.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -1034,13 +1035,6 @@ static inline void vm_stat_account(struct mm_struct *mm,
 }
 #endif /* CONFIG_PROC_FS */
 
-static inline void
-debug_check_no_locks_freed(const void *from, unsigned long len)
-{
-	mutex_debug_check_no_locks_freed(from, len);
-	rt_mutex_debug_check_no_locks_freed(from, len);
-}
-
 #ifndef CONFIG_DEBUG_PAGEALLOC
 static inline void
 kernel_map_pages(struct page *page, int numpages, int enable)

include/linux/mutex-debug.h

@@ -8,16 +8,10 @@
  */
 
 #define __DEBUG_MUTEX_INITIALIZER(lockname)				\
-	, .held_list = LIST_HEAD_INIT(lockname.held_list), \
+	, .magic = &lockname
-	  .name = #lockname , .magic = &lockname
 
-#define mutex_init(sem)		__mutex_init(sem, __FUNCTION__)
+#define mutex_init(sem)		__mutex_init(sem, __FILE__":"#sem)
 
 extern void FASTCALL(mutex_destroy(struct mutex *lock));
 
-extern void mutex_debug_show_all_locks(void);
-extern void mutex_debug_show_held_locks(struct task_struct *filter);
-extern void mutex_debug_check_no_locks_held(struct task_struct *task);
-extern void mutex_debug_check_no_locks_freed(const void *from, unsigned long len);
-
 #endif

include/linux/mutex.h

@@ -50,8 +50,6 @@ struct mutex {
 	struct list_head	wait_list;
 #ifdef CONFIG_DEBUG_MUTEXES
 	struct thread_info	*owner;
-	struct list_head	held_list;
-	unsigned long		acquire_ip;
 	const char 		*name;
 	void			*magic;
 #endif
@@ -76,10 +74,6 @@ struct mutex_waiter {
 # define __DEBUG_MUTEX_INITIALIZER(lockname)
 # define mutex_init(mutex)			__mutex_init(mutex, NULL)
 # define mutex_destroy(mutex)				do { } while (0)
-# define mutex_debug_show_all_locks()			do { } while (0)
-# define mutex_debug_show_held_locks(p)			do { } while (0)
-# define mutex_debug_check_no_locks_held(task)		do { } while (0)
-# define mutex_debug_check_no_locks_freed(from, len)	do { } while (0)
 #endif
 
 #define __MUTEX_INITIALIZER(lockname) \

include/linux/rtmutex.h

@@ -29,8 +29,6 @@ struct rt_mutex {
 	struct task_struct	*owner;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 	int			save_state;
-	struct list_head	held_list_entry;
-	unsigned long		acquire_ip;
 	const char 		*name, *file;
 	int			line;
 	void			*magic;
@@ -98,14 +96,6 @@ extern int rt_mutex_trylock(struct rt_mutex *lock);
 
 extern void rt_mutex_unlock(struct rt_mutex *lock);
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-# define INIT_RT_MUTEX_DEBUG(tsk)					\
-	.held_list_head	= LIST_HEAD_INIT(tsk.held_list_head),		\
-	.held_list_lock	= SPIN_LOCK_UNLOCKED
-#else
-# define INIT_RT_MUTEX_DEBUG(tsk)
-#endif
-
 #ifdef CONFIG_RT_MUTEXES
 # define INIT_RT_MUTEXES(tsk)						\
 	.pi_waiters	= PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock),	\

include/linux/sched.h

@@ -865,10 +865,6 @@ struct task_struct {
 	struct plist_head pi_waiters;
 	/* Deadlock detection and priority inheritance handling */
 	struct rt_mutex_waiter *pi_blocked_on;
-# ifdef CONFIG_DEBUG_RT_MUTEXES
-	spinlock_t held_list_lock;
-	struct list_head held_list_head;
-# endif
 #endif
 
 #ifdef CONFIG_DEBUG_MUTEXES

init/main.c

@@ -47,6 +47,7 @@
 #include <linux/key.h>
 #include <linux/unwind.h>
 #include <linux/buffer_head.h>
+#include <linux/debug_locks.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -511,6 +512,13 @@ asmlinkage void __init start_kernel(void)
 	console_init();
 	if (panic_later)
 		panic(panic_later, panic_param);
+	/*
+	 * Need to run this when irqs are enabled, because it wants
+	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
+	 * too:
+	 */
+	locking_selftest();
+
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (initrd_start && !initrd_below_start_ok &&
 			initrd_start < min_low_pfn << PAGE_SHIFT) {

kernel/exit.c

@@ -933,10 +933,9 @@ fastcall NORET_TYPE void do_exit(long code)
 	if (unlikely(current->pi_state_cache))
 		kfree(current->pi_state_cache);
 	/*
-	 * If DEBUG_MUTEXES is on, make sure we are holding no locks:
+	 * Make sure we are holding no locks:
 	 */
-	mutex_debug_check_no_locks_held(tsk);
+	debug_check_no_locks_held(tsk);
-	rt_mutex_debug_check_no_locks_held(tsk);
 
 	if (tsk->io_context)
 		exit_io_context();

kernel/fork.c

@@ -919,10 +919,6 @@ static inline void rt_mutex_init_task(struct task_struct *p)
 	spin_lock_init(&p->pi_lock);
 	plist_head_init(&p->pi_waiters, &p->pi_lock);
 	p->pi_blocked_on = NULL;
-# ifdef CONFIG_DEBUG_RT_MUTEXES
-	spin_lock_init(&p->held_list_lock);
-	INIT_LIST_HEAD(&p->held_list_head);
-# endif
 #endif
 }
 

kernel/mutex-debug.c

@@ -20,52 +20,19 @@
 #include <linux/spinlock.h>
 #include <linux/kallsyms.h>
 #include <linux/interrupt.h>
+#include <linux/debug_locks.h>
 
 #include "mutex-debug.h"
 
-/*
- * We need a global lock when we walk through the multi-process
- * lock tree. Only used in the deadlock-debugging case.
- */
-DEFINE_SPINLOCK(debug_mutex_lock);
-
-/*
- * All locks held by all tasks, in a single global list:
- */
-LIST_HEAD(debug_mutex_held_locks);
-
-/*
- * 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)
-
-/*
- * "mutex debugging enabled" flag. We turn it off when we detect
- * the first problem because we dont want to recurse back
- * into the tracing code when doing error printk or
- * executing a BUG():
- */
-int debug_mutex_on = 1;
-
 /*
  * Must be called with lock->wait_lock held.
  */
-void debug_mutex_set_owner(struct mutex *lock,
+void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
-			   struct thread_info *new_owner __IP_DECL__)
 {
 	lock->owner = new_owner;
-	DEBUG_LOCKS_WARN_ON(!list_empty(&lock->held_list));
-	if (debug_mutex_on) {
-		list_add_tail(&lock->held_list, &debug_mutex_held_locks);
-		lock->acquire_ip = ip;
-	}
 }
 
-void debug_mutex_init_waiter(struct mutex_waiter *waiter)
+void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
 {
 	memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
 	waiter->magic = waiter;
@@ -87,9 +54,10 @@ void debug_mutex_free_waiter(struct mutex_waiter *waiter)
 }
 
 void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
-			    struct thread_info *ti __IP_DECL__)
+			    struct thread_info *ti)
 {
 	SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
+
 	/* Mark the current thread as blocked on the lock: */
 	ti->task->blocked_on = waiter;
 	waiter->lock = lock;
@@ -109,13 +77,10 @@ void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 
 void debug_mutex_unlock(struct mutex *lock)
 {
+	DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
 	DEBUG_LOCKS_WARN_ON(lock->magic != lock);
 	DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
 	DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
-	if (debug_mutex_on) {
-		DEBUG_LOCKS_WARN_ON(list_empty(&lock->held_list));
-		list_del_init(&lock->held_list);
-	}
 }
 
 void debug_mutex_init(struct mutex *lock, const char *name)
@@ -123,10 +88,8 @@ void debug_mutex_init(struct mutex *lock, const char *name)
 	/*
 	 * Make sure we are not reinitializing a held lock:
 	 */
-	mutex_debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
 	lock->owner = NULL;
-	INIT_LIST_HEAD(&lock->held_list);
-	lock->name = name;
 	lock->magic = lock;
 }
 

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,
+extern void
-				  struct thread_info *new_owner __IP_DECL__);
+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);
+extern void debug_mutex_init(struct mutex *lock, const char *name,
-
+			     struct lock_class_key *key);
-#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)
 
 #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); \
+		local_irq_save(flags);			\
-		spin_lock(lock);			\
+		__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);			\
+		__raw_spin_unlock(&(lock)->raw_lock);	\
-		debug_spin_unlock_restore(&debug_mutex_lock, flags);	\
+		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
-

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 @@ 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
+static fastcall inline void
-__mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
+__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);

kernel/mutex.h

@@ -16,22 +16,15 @@
 #define mutex_remove_waiter(lock, waiter, ti) \
 		__list_del((waiter)->list.prev, (waiter)->list.next)
 
-#define DEBUG_LOCKS_WARN_ON(c)				do { } while (0)
 #define debug_mutex_set_owner(lock, new_owner)		do { } while (0)
 #define debug_mutex_clear_owner(lock)			do { } while (0)
-#define debug_mutex_init_waiter(waiter)			do { } while (0)
 #define debug_mutex_wake_waiter(lock, waiter)		do { } while (0)
 #define debug_mutex_free_waiter(waiter)			do { } while (0)
-#define debug_mutex_add_waiter(lock, waiter, ti, ip)	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)
 
-/*
+static inline void
- * Return-address parameters/declarations. They are very useful for
+debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
- * debugging, but add overhead in the !DEBUG case - so we go the
+{
- * trouble of using this not too elegant but zero-cost solution:
+}
- */
-#define __IP_DECL__
-#define __IP__
-#define __RET_IP__
-

kernel/rtmutex-debug.c

@@ -26,6 +26,7 @@
 #include <linux/interrupt.h>
 #include <linux/plist.h>
 #include <linux/fs.h>
+#include <linux/debug_locks.h>
 
 #include "rtmutex_common.h"
 
@@ -45,8 +46,6 @@ do {								\
 		console_verbose();				\
 		if (spin_is_locked(&current->pi_lock))		\
 			spin_unlock(&current->pi_lock);		\
-		if (spin_is_locked(&current->held_list_lock))	\
-			spin_unlock(&current->held_list_lock);	\
 	}							\
 } while (0)
 
@@ -105,14 +104,6 @@ static void printk_task(task_t *p)
 		printk("<none>");
 }
 
-static void printk_task_short(task_t *p)
-{
-	if (p)
-		printk("%s/%d [%p, %3d]", p->comm, p->pid, p, p->prio);
-	else
-		printk("<none>");
-}
-
 static void printk_lock(struct rt_mutex *lock, int print_owner)
 {
 	if (lock->name)
@@ -128,222 +119,6 @@ static void printk_lock(struct rt_mutex *lock, int print_owner)
 		printk_task(rt_mutex_owner(lock));
 		printk("\n");
 	}
-	if (rt_mutex_owner(lock)) {
-		printk("... acquired at:               ");
-		print_symbol("%s\n", lock->acquire_ip);
-	}
-}
-
-static void printk_waiter(struct rt_mutex_waiter *w)
-{
-	printk("-------------------------\n");
-	printk("| waiter struct %p:\n", w);
-	printk("| w->list_entry: [DP:%p/%p|SP:%p/%p|PRI:%d]\n",
-	       w->list_entry.plist.prio_list.prev, w->list_entry.plist.prio_list.next,
-	       w->list_entry.plist.node_list.prev, w->list_entry.plist.node_list.next,
-	       w->list_entry.prio);
-	printk("| w->pi_list_entry: [DP:%p/%p|SP:%p/%p|PRI:%d]\n",
-	       w->pi_list_entry.plist.prio_list.prev, w->pi_list_entry.plist.prio_list.next,
-	       w->pi_list_entry.plist.node_list.prev, w->pi_list_entry.plist.node_list.next,
-	       w->pi_list_entry.prio);
-	printk("\n| lock:\n");
-	printk_lock(w->lock, 1);
-	printk("| w->ti->task:\n");
-	printk_task(w->task);
-	printk("| blocked at:  ");
-	print_symbol("%s\n", w->ip);
-	printk("-------------------------\n");
-}
-
-static void show_task_locks(task_t *p)
-{
-	switch (p->state) {
-	case TASK_RUNNING:		printk("R"); break;
-	case TASK_INTERRUPTIBLE:	printk("S"); break;
-	case TASK_UNINTERRUPTIBLE:	printk("D"); break;
-	case TASK_STOPPED:		printk("T"); break;
-	case EXIT_ZOMBIE:		printk("Z"); break;
-	case EXIT_DEAD:			printk("X"); break;
-	default:			printk("?"); break;
-	}
-	printk_task(p);
-	if (p->pi_blocked_on) {
-		struct rt_mutex *lock = p->pi_blocked_on->lock;
-
-		printk(" blocked on:");
-		printk_lock(lock, 1);
-	} else
-		printk(" (not blocked)\n");
-}
-
-void rt_mutex_show_held_locks(task_t *task, int verbose)
-{
-	struct list_head *curr, *cursor = NULL;
-	struct rt_mutex *lock;
-	task_t *t;
-	unsigned long flags;
-	int count = 0;
-
-	if (!rt_trace_on)
-		return;
-
-	if (verbose) {
-		printk("------------------------------\n");
-		printk("| showing all locks held by: |  (");
-		printk_task_short(task);
-		printk("):\n");
-		printk("------------------------------\n");
-	}
-
-next:
-	spin_lock_irqsave(&task->held_list_lock, flags);
-	list_for_each(curr, &task->held_list_head) {
-		if (cursor && curr != cursor)
-			continue;
-		lock = list_entry(curr, struct rt_mutex, held_list_entry);
-		t = rt_mutex_owner(lock);
-		WARN_ON(t != task);
-		count++;
-		cursor = curr->next;
-		spin_unlock_irqrestore(&task->held_list_lock, flags);
-
-		printk("\n#%03d:            ", count);
-		printk_lock(lock, 0);
-		goto next;
-	}
-	spin_unlock_irqrestore(&task->held_list_lock, flags);
-
-	printk("\n");
-}
-
-void rt_mutex_show_all_locks(void)
-{
-	task_t *g, *p;
-	int count = 10;
-	int unlock = 1;
-
-	printk("\n");
-	printk("----------------------\n");
-	printk("| showing all tasks: |\n");
-	printk("----------------------\n");
-
-	/*
-	 * Here we try to get the tasklist_lock as hard as possible,
-	 * if not successful after 2 seconds we ignore it (but keep
-	 * trying). This is to enable a debug printout even if a
-	 * tasklist_lock-holding task deadlocks or crashes.
-	 */
-retry:
-	if (!read_trylock(&tasklist_lock)) {
-		if (count == 10)
-			printk("hm, tasklist_lock locked, retrying... ");
-		if (count) {
-			count--;
-			printk(" #%d", 10-count);
-			mdelay(200);
-			goto retry;
-		}
-		printk(" ignoring it.\n");
-		unlock = 0;
-	}
-	if (count != 10)
-		printk(" locked it.\n");
-
-	do_each_thread(g, p) {
-		show_task_locks(p);
-		if (!unlock)
-			if (read_trylock(&tasklist_lock))
-				unlock = 1;
-	} while_each_thread(g, p);
-
-	printk("\n");
-
-	printk("-----------------------------------------\n");
-	printk("| showing all locks held in the system: |\n");
-	printk("-----------------------------------------\n");
-
-	do_each_thread(g, p) {
-		rt_mutex_show_held_locks(p, 0);
-		if (!unlock)
-			if (read_trylock(&tasklist_lock))
-				unlock = 1;
-	} while_each_thread(g, p);
-
-
-	printk("=============================================\n\n");
-
-	if (unlock)
-		read_unlock(&tasklist_lock);
-}
-
-void rt_mutex_debug_check_no_locks_held(task_t *task)
-{
-	struct rt_mutex_waiter *w;
-	struct list_head *curr;
-	struct rt_mutex *lock;
-
-	if (!rt_trace_on)
-		return;
-	if (!rt_prio(task->normal_prio) && rt_prio(task->prio)) {
-		printk("BUG: PI priority boost leaked!\n");
-		printk_task(task);
-		printk("\n");
-	}
-	if (list_empty(&task->held_list_head))
-		return;
-
-	spin_lock(&task->pi_lock);
-	plist_for_each_entry(w, &task->pi_waiters, pi_list_entry) {
-		TRACE_OFF();
-
-		printk("hm, PI interest held at exit time? Task:\n");
-		printk_task(task);
-		printk_waiter(w);
-		return;
-	}
-	spin_unlock(&task->pi_lock);
-
-	list_for_each(curr, &task->held_list_head) {
-		lock = list_entry(curr, struct rt_mutex, held_list_entry);
-
-		printk("BUG: %s/%d, lock held at task exit time!\n",
-		       task->comm, task->pid);
-		printk_lock(lock, 1);
-		if (rt_mutex_owner(lock) != task)
-			printk("exiting task is not even the owner??\n");
-	}
-}
-
-int rt_mutex_debug_check_no_locks_freed(const void *from, unsigned long len)
-{
-	const void *to = from + len;
-	struct list_head *curr;
-	struct rt_mutex *lock;
-	unsigned long flags;
-	void *lock_addr;
-
-	if (!rt_trace_on)
-		return 0;
-
-	spin_lock_irqsave(&current->held_list_lock, flags);
-	list_for_each(curr, &current->held_list_head) {
-		lock = list_entry(curr, struct rt_mutex, held_list_entry);
-		lock_addr = lock;
-		if (lock_addr < from || lock_addr >= to)
-			continue;
-		TRACE_OFF();
-
-		printk("BUG: %s/%d, active lock [%p(%p-%p)] freed!\n",
-			current->comm, current->pid, lock, from, to);
-		dump_stack();
-		printk_lock(lock, 1);
-		if (rt_mutex_owner(lock) != current)
-			printk("freeing task is not even the owner??\n");
-		return 1;
-	}
-	spin_unlock_irqrestore(&current->held_list_lock, flags);
-
-	return 0;
 }
 
 void rt_mutex_debug_task_free(struct task_struct *task)
@@ -395,85 +170,41 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
 	       current->comm, current->pid);
 	printk_lock(waiter->lock, 1);
 
-	printk("... trying at:                 ");
-	print_symbol("%s\n", waiter->ip);
-
 	printk("\n2) %s/%d is blocked on this lock:\n", task->comm, task->pid);
 	printk_lock(waiter->deadlock_lock, 1);
 
-	rt_mutex_show_held_locks(current, 1);
+	debug_show_held_locks(current);
-	rt_mutex_show_held_locks(task, 1);
+	debug_show_held_locks(task);
 
 	printk("\n%s/%d's [blocked] stackdump:\n\n", task->comm, task->pid);
 	show_stack(task, NULL);
 	printk("\n%s/%d's [current] stackdump:\n\n",
 	       current->comm, current->pid);
 	dump_stack();
-	rt_mutex_show_all_locks();
+	debug_show_all_locks();
+
 	printk("[ turning off deadlock detection."
 	       "Please report this trace. ]\n\n");
 	local_irq_disable();
 }
 
-void debug_rt_mutex_lock(struct rt_mutex *lock __IP_DECL__)
+void debug_rt_mutex_lock(struct rt_mutex *lock)
 {
-	unsigned long flags;
-
-	if (rt_trace_on) {
-		TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));
-
-		spin_lock_irqsave(&current->held_list_lock, flags);
-		list_add_tail(&lock->held_list_entry, &current->held_list_head);
-		spin_unlock_irqrestore(&current->held_list_lock, flags);
-
-		lock->acquire_ip = ip;
-	}
 }
 
 void debug_rt_mutex_unlock(struct rt_mutex *lock)
 {
-	unsigned long flags;
-
-	if (rt_trace_on) {
 	TRACE_WARN_ON_LOCKED(rt_mutex_owner(lock) != current);
-		TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));
-
-		spin_lock_irqsave(&current->held_list_lock, flags);
-		list_del_init(&lock->held_list_entry);
-		spin_unlock_irqrestore(&current->held_list_lock, flags);
-	}
 }
 
-void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
+void
-			       struct task_struct *powner __IP_DECL__)
+debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
 {
-	unsigned long flags;
-
-	if (rt_trace_on) {
-		TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));
-
-		spin_lock_irqsave(&powner->held_list_lock, flags);
-		list_add_tail(&lock->held_list_entry, &powner->held_list_head);
-		spin_unlock_irqrestore(&powner->held_list_lock, flags);
-
-		lock->acquire_ip = ip;
-	}
 }
 
 void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
 {
-	unsigned long flags;
+	TRACE_WARN_ON_LOCKED(!rt_mutex_owner(lock));
-
-	if (rt_trace_on) {
-		struct task_struct *owner = rt_mutex_owner(lock);
-
-		TRACE_WARN_ON_LOCKED(!owner);
-		TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));
-
-		spin_lock_irqsave(&owner->held_list_lock, flags);
-		list_del_init(&lock->held_list_entry);
-		spin_unlock_irqrestore(&owner->held_list_lock, flags);
-	}
 }
 
 void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
@@ -493,15 +224,12 @@ void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
 
 void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)
 {
-	void *addr = lock;
+	/*
-
+	 * Make sure we are not reinitializing a held lock:
-	if (rt_trace_on) {
+	 */
-		rt_mutex_debug_check_no_locks_freed(addr,
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
-						    sizeof(struct rt_mutex));
-		INIT_LIST_HEAD(&lock->held_list_entry);
 	lock->name = name;
 }
-}
 
 void rt_mutex_deadlock_account_lock(struct rt_mutex *lock, task_t *task)
 {

kernel/rtmutex-debug.h

@@ -9,20 +9,16 @@
  * This file contains macros used solely by rtmutex.c. Debug version.
  */
 
-#define __IP_DECL__		, unsigned long ip
-#define __IP__			, ip
-#define __RET_IP__		, (unsigned long)__builtin_return_address(0)
-
 extern void
 rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task);
 extern void rt_mutex_deadlock_account_unlock(struct task_struct *task);
 extern void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
 extern void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter);
 extern void debug_rt_mutex_init(struct rt_mutex *lock, const char *name);
-extern void debug_rt_mutex_lock(struct rt_mutex *lock __IP_DECL__);
+extern void debug_rt_mutex_lock(struct rt_mutex *lock);
 extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
 extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
-				      struct task_struct *powner __IP_DECL__);
+				      struct task_struct *powner);
 extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
 extern void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *waiter,
 				    struct rt_mutex *lock);

kernel/rtmutex.c

@@ -161,8 +161,7 @@ static int rt_mutex_adjust_prio_chain(task_t *task,
 				      int deadlock_detect,
 				      struct rt_mutex *orig_lock,
 				      struct rt_mutex_waiter *orig_waiter,
-				      struct task_struct *top_task
+				      struct task_struct *top_task)
-				      __IP_DECL__)
 {
 	struct rt_mutex *lock;
 	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
@@ -357,7 +356,7 @@ static inline int try_to_steal_lock(struct rt_mutex *lock)
  *
  * Must be called with lock->wait_lock held.
  */
-static int try_to_take_rt_mutex(struct rt_mutex *lock __IP_DECL__)
+static int try_to_take_rt_mutex(struct rt_mutex *lock)
 {
 	/*
 	 * We have to be careful here if the atomic speedups are
@@ -384,7 +383,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock __IP_DECL__)
 		return 0;
 
 	/* We got the lock. */
-	debug_rt_mutex_lock(lock __IP__);
+	debug_rt_mutex_lock(lock);
 
 	rt_mutex_set_owner(lock, current, 0);
 
@@ -402,8 +401,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock __IP_DECL__)
  */
 static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 				   struct rt_mutex_waiter *waiter,
-				   int detect_deadlock
+				   int detect_deadlock)
-				   __IP_DECL__)
 {
 	struct rt_mutex_waiter *top_waiter = waiter;
 	task_t *owner = rt_mutex_owner(lock);
@@ -454,7 +452,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 	spin_unlock(&lock->wait_lock);
 
 	res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
-					 current __IP__);
+					 current);
 
 	spin_lock(&lock->wait_lock);
 
@@ -526,7 +524,7 @@ static void wakeup_next_waiter(struct rt_mutex *lock)
  * Must be called with lock->wait_lock held
  */
 static void remove_waiter(struct rt_mutex *lock,
-			  struct rt_mutex_waiter *waiter  __IP_DECL__)
+			  struct rt_mutex_waiter *waiter)
 {
 	int first = (waiter == rt_mutex_top_waiter(lock));
 	int boost = 0;
@@ -568,7 +566,7 @@ static void remove_waiter(struct rt_mutex *lock,
 
 	spin_unlock(&lock->wait_lock);
 
-	rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current __IP__);
+	rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
 
 	spin_lock(&lock->wait_lock);
 }
@@ -595,7 +593,7 @@ void rt_mutex_adjust_pi(struct task_struct *task)
 	get_task_struct(task);
 	spin_unlock_irqrestore(&task->pi_lock, flags);
 
-	rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task __RET_IP__);
+	rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
 }
 
 /*
@@ -604,7 +602,7 @@ void rt_mutex_adjust_pi(struct task_struct *task)
 static int __sched
 rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		  struct hrtimer_sleeper *timeout,
-		  int detect_deadlock __IP_DECL__)
+		  int detect_deadlock)
 {
 	struct rt_mutex_waiter waiter;
 	int ret = 0;
@@ -615,7 +613,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 	spin_lock(&lock->wait_lock);
 
 	/* Try to acquire the lock again: */
-	if (try_to_take_rt_mutex(lock __IP__)) {
+	if (try_to_take_rt_mutex(lock)) {
 		spin_unlock(&lock->wait_lock);
 		return 0;
 	}
@@ -629,7 +627,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 
 	for (;;) {
 		/* Try to acquire the lock: */
-		if (try_to_take_rt_mutex(lock __IP__))
+		if (try_to_take_rt_mutex(lock))
 			break;
 
 		/*
@@ -653,7 +651,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		 */
 		if (!waiter.task) {
 			ret = task_blocks_on_rt_mutex(lock, &waiter,
-						      detect_deadlock __IP__);
+						      detect_deadlock);
 			/*
 			 * If we got woken up by the owner then start loop
 			 * all over without going into schedule to try
@@ -680,7 +678,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 	set_current_state(TASK_RUNNING);
 
 	if (unlikely(waiter.task))
-		remove_waiter(lock, &waiter __IP__);
+		remove_waiter(lock, &waiter);
 
 	/*
 	 * try_to_take_rt_mutex() sets the waiter bit
@@ -711,7 +709,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
  * Slow path try-lock function:
  */
 static inline int
-rt_mutex_slowtrylock(struct rt_mutex *lock __IP_DECL__)
+rt_mutex_slowtrylock(struct rt_mutex *lock)
 {
 	int ret = 0;
 
@@ -719,7 +717,7 @@ rt_mutex_slowtrylock(struct rt_mutex *lock __IP_DECL__)
 
 	if (likely(rt_mutex_owner(lock) != current)) {
 
-		ret = try_to_take_rt_mutex(lock __IP__);
+		ret = try_to_take_rt_mutex(lock);
 		/*
 		 * try_to_take_rt_mutex() sets the lock waiters
 		 * bit unconditionally. Clean this up.
@@ -769,13 +767,13 @@ rt_mutex_fastlock(struct rt_mutex *lock, int state,
 		  int detect_deadlock,
 		  int (*slowfn)(struct rt_mutex *lock, int state,
 				struct hrtimer_sleeper *timeout,
-				int detect_deadlock __IP_DECL__))
+				int detect_deadlock))
 {
 	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
 		rt_mutex_deadlock_account_lock(lock, current);
 		return 0;
 	} else
-		return slowfn(lock, state, NULL, detect_deadlock __RET_IP__);
+		return slowfn(lock, state, NULL, detect_deadlock);
 }
 
 static inline int
@@ -783,24 +781,24 @@ rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
 			struct hrtimer_sleeper *timeout, int detect_deadlock,
 			int (*slowfn)(struct rt_mutex *lock, int state,
 				      struct hrtimer_sleeper *timeout,
-				      int detect_deadlock __IP_DECL__))
+				      int detect_deadlock))
 {
 	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
 		rt_mutex_deadlock_account_lock(lock, current);
 		return 0;
 	} else
-		return slowfn(lock, state, timeout, detect_deadlock __RET_IP__);
+		return slowfn(lock, state, timeout, detect_deadlock);
 }
 
 static inline int
 rt_mutex_fasttrylock(struct rt_mutex *lock,
-		     int (*slowfn)(struct rt_mutex *lock __IP_DECL__))
+		     int (*slowfn)(struct rt_mutex *lock))
 {
 	if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
 		rt_mutex_deadlock_account_lock(lock, current);
 		return 1;
 	}
-	return slowfn(lock __RET_IP__);
+	return slowfn(lock);
 }
 
 static inline void
@@ -948,7 +946,7 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
 				struct task_struct *proxy_owner)
 {
 	__rt_mutex_init(lock, NULL);
-	debug_rt_mutex_proxy_lock(lock, proxy_owner __RET_IP__);
+	debug_rt_mutex_proxy_lock(lock, proxy_owner);
 	rt_mutex_set_owner(lock, proxy_owner, 0);
 	rt_mutex_deadlock_account_lock(lock, proxy_owner);
 }

kernel/rtmutex.h

@@ -10,9 +10,6 @@
  * Non-debug version.
  */
 
-#define __IP_DECL__
-#define __IP__
-#define __RET_IP__
 #define rt_mutex_deadlock_check(l)			(0)
 #define rt_mutex_deadlock_account_lock(m, t)		do { } while (0)
 #define rt_mutex_deadlock_account_unlock(l)		do { } while (0)

kernel/sched.c

@@ -30,6 +30,7 @@
 #include <linux/capability.h>
 #include <linux/completion.h>
 #include <linux/kernel_stat.h>
+#include <linux/debug_locks.h>
 #include <linux/security.h>
 #include <linux/notifier.h>
 #include <linux/profile.h>
@@ -3142,12 +3143,13 @@ void fastcall add_preempt_count(int val)
 	/*
 	 * Underflow?
 	 */
-	BUG_ON((preempt_count() < 0));
+	if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
+		return;
 	preempt_count() += val;
 	/*
 	 * Spinlock count overflowing soon?
 	 */
-	BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
+	DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
 }
 EXPORT_SYMBOL(add_preempt_count);
 
@@ -3156,11 +3158,15 @@ void fastcall sub_preempt_count(int val)
 	/*
 	 * Underflow?
 	 */
-	BUG_ON(val > preempt_count());
+	if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
+		return;
 	/*
 	 * Is the spinlock portion underflowing?
 	 */
-	BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK));
+	if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+			!(preempt_count() & PREEMPT_MASK)))
+		return;
+
 	preempt_count() -= val;
 }
 EXPORT_SYMBOL(sub_preempt_count);
@@ -4690,7 +4696,7 @@ void show_state(void)
 	} while_each_thread(g, p);
 
 	read_unlock(&tasklist_lock);
-	mutex_debug_show_all_locks();
+	debug_show_all_locks();
 }
 
 /**

lib/Makefile

@@ -11,7 +11,7 @@ lib-$(CONFIG_SMP) += cpumask.o
 
 lib-y	+= kobject.o kref.o kobject_uevent.o klist.o
 
-obj-y += sort.o parser.o halfmd4.o iomap_copy.o
+obj-y += sort.o parser.o halfmd4.o iomap_copy.o debug_locks.o
 
 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
 CFLAGS_kobject.o += -DDEBUG

lib/debug_locks.c

@@ -0,0 +1,45 @@
+/*
+ * lib/debug_locks.c
+ *
+ * Generic place for common debugging facilities for various locks:
+ * spinlocks, rwlocks, mutexes and rwsems.
+ *
+ * Started by Ingo Molnar:
+ *
+ *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/rwsem.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/debug_locks.h>
+
+/*
+ * We want to turn all lock-debugging facilities on/off at once,
+ * via a global flag. The reason is that once a single bug has been
+ * detected and reported, there might be cascade of followup bugs
+ * that would just muddy the log. So we report the first one and
+ * shut up after that.
+ */
+int debug_locks = 1;
+
+/*
+ * The locking-testsuite uses <debug_locks_silent> to get a
+ * 'silent failure': nothing is printed to the console when
+ * a locking bug is detected.
+ */
+int debug_locks_silent;
+
+/*
+ * Generic 'turn off all lock debugging' function:
+ */
+int debug_locks_off(void)
+{
+	if (xchg(&debug_locks, 0)) {
+		if (!debug_locks_silent) {
+			console_verbose();
+			return 1;
+		}
+	}
+	return 0;
+}

lib/spinlock_debug.c

@@ -8,14 +8,17 @@
 
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
+#include <linux/debug_locks.h>
 #include <linux/delay.h>
+#include <linux/module.h>
 
 static void spin_bug(spinlock_t *lock, const char *msg)
 {
-	static long print_once = 1;
 	struct task_struct *owner = NULL;
 
-	if (xchg(&print_once, 0)) {
+	if (!debug_locks_off())
+		return;
+
 	if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
 		owner = lock->owner;
 	printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
@@ -28,18 +31,12 @@ static void spin_bug(spinlock_t *lock, const char *msg)
 		owner ? owner->pid : -1,
 		lock->owner_cpu);
 	dump_stack();
-#ifdef CONFIG_SMP
-		/*
-		 * We cannot continue on SMP:
-		 */
-//		panic("bad locking");
-#endif
-	}
 }
 
 #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
 
-static inline void debug_spin_lock_before(spinlock_t *lock)
+static inline void
+debug_spin_lock_before(spinlock_t *lock)
 {
 	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
 	SPIN_BUG_ON(lock->owner == current, lock, "recursion");
@@ -118,20 +115,13 @@ void _raw_spin_unlock(spinlock_t *lock)
 
 static void rwlock_bug(rwlock_t *lock, const char *msg)
 {
-	static long print_once = 1;
+	if (!debug_locks_off())
+		return;
 
-	if (xchg(&print_once, 0)) {
 	printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
 		msg, raw_smp_processor_id(), current->comm,
 		current->pid, lock);
 	dump_stack();
-#ifdef CONFIG_SMP
-		/*
-		 * We cannot continue on SMP:
-		 */
-		panic("bad locking");
-#endif
-	}
 }
 
 #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)

mm/vmalloc.c

@@ -330,6 +330,8 @@ void __vunmap(void *addr, int deallocate_pages)
 		return;
 	}
 
+	debug_check_no_locks_freed(addr, area->size);
+
 	if (deallocate_pages) {
 		int i;