[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/include/linux/debug_locks.h b/include/linux/debug_locks.h
new file mode 100644
index 0000000..6a70478
--- /dev/null
+++ b/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
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 3a25695..678c1a9 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -124,7 +124,6 @@
.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
.fs_excl = ATOMIC_INIT(0), \
.pi_lock = SPIN_LOCK_UNLOCKED, \
- INIT_RT_MUTEXES(tsk) \
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7517952..990957e 100644
--- a/include/linux/mm.h
+++ b/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 @@
}
#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)
diff --git a/include/linux/mutex-debug.h b/include/linux/mutex-debug.h
index 8b5769f..70a2609 100644
--- a/include/linux/mutex-debug.h
+++ b/include/linux/mutex-debug.h
@@ -7,17 +7,11 @@
* Mutexes - debugging helpers:
*/
-#define __DEBUG_MUTEX_INITIALIZER(lockname) \
- , .held_list = LIST_HEAD_INIT(lockname.held_list), \
- .name = #lockname , .magic = &lockname
+#define __DEBUG_MUTEX_INITIALIZER(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
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index f1ac507..caafecd 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -50,8 +50,6 @@
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 @@
# 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) \
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index fa4a3b8..5d41dee 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -29,8 +29,6 @@
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 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), \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index aaf7233..bdabeee 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -865,10 +865,6 @@
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