[tip:core/locking] lockdep: Print more info when MAX_LOCK_DEPTH is exceeded

[tip-bot for Ben Greear <greearb@candelatech.com>]

Commit-ID:  7a508076d4efdfd4fcb6fbd50a32d2c1a6e98791
Gitweb:     http://git.kernel.org/tip/7a508076d4efdfd4fcb6fbd50a32d2c1a6e98791
Author:     Ben Greear <greearb@candelatech.com>
AuthorDate: Wed, 6 Feb 2013 10:56:19 -0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 7 Feb 2013 12:17:43 +0100

lockdep: Print more info when MAX_LOCK_DEPTH is exceeded

This helps debug cases where a lock is acquired over and
over without being released.

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1360176979-4421-1-git-send-email-greearb@candelatech.com
[ Changed the printout ordering. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/lockdep.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index c783e80..1966746 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3192,9 +3192,14 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 #endif
 	if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
 		debug_locks_off();
-		printk("BUG: MAX_LOCK_DEPTH too low!\n");
+		printk("BUG: MAX_LOCK_DEPTH too low, depth: %i  max: %lu!\n",
+		       curr->lockdep_depth, MAX_LOCK_DEPTH);
 		printk("turning off the locking correctness validator.\n");
+
+		lockdep_print_held_locks(current);
+		debug_show_all_locks();
 		dump_stack();
+
 		return 0;
 	}