[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, 5 insertions, 12 deletions

diff --git a/kernel/mutex.h b/kernel/mutex.h
index 7e1ed48d1a6c..aeb2d916aa0e 100644
--- a/kernel/mutex.h
+++ b/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)
 
-/*
- * Return-address parameters/declarations. They are very useful for
- * 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__
-
+static inline void
+debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+}