[PATCH] lockdep: show more details about self-test failures

Make the locking self-test failures (of 'FAILURE' type) easier to debug by
printing more information.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 6 insertions, 1 deletions

diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
index 952bee79a8f3..a1c10b0c4cf0 100644
--- a/include/linux/debug_locks.h
+++ b/include/linux/debug_locks.h
@@ -24,7 +24,7 @@ extern int debug_locks_off(void);
         int __ret = 0;                                                  \
                                                                         \
         if (unlikely(c)) {                                              \
-                if (debug_locks_off())                                  \
+                if (debug_locks_silent || debug_locks_off())            \
                         WARN_ON(1);                                     \
                 __ret = 1;                                              \
         }                                                               \
diff --git a/kernel/mutex-debug.c b/kernel/mutex-debug.c
index 18651641a7b5..841539d72c55 100644
--- a/kernel/mutex-debug.c
+++ b/kernel/mutex-debug.c
@@ -77,6 +77,9 @@ void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 
 void debug_mutex_unlock(struct mutex *lock)
 {
+        if (unlikely(!debug_locks))
+                return;
+
         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);
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 7945787f439a..280332c1827c 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -963,7 +963,9 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
                         printk("failed|");
                 } else {
                         unexpected_testcase_failures++;
+
                         printk("FAILED|");
+                        dump_stack();
                 }
         } else {
                 testcase_successes++;