Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  mutex: Fix optimistic spinning vs. BKL

kernel/mutex.c

@@ -171,6 +171,13 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	for (;;) {
 		struct thread_info *owner;
 
+		/*
+		 * If we own the BKL, then don't spin. The owner of
+		 * the mutex might be waiting on us to release the BKL.
+		 */
+		if (unlikely(current->lock_depth >= 0))
+			break;
+
 		/*
 		 * If there's an owner, wait for it to either
 		 * release the lock or go to sleep.