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

[tip-bot for Ben Greear]

Commit-ID:  c0540606837af79b2ae101e5e7b2206e3844d150
Gitweb:     http://git.kernel.org/tip/c0540606837af79b2ae101e5e7b2206e3844d150
Author:     Ben Greear <greearb@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 6 Feb 2013 10:56:19 -0800
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 19 Feb 2013 08:42:44 +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@xxxxxxxxxxx>
Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1360176979-4421-1-git-send-email-greearb@xxxxxxxxxxxxxxx
[ Changed the printout ordering. ]
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/lockdep.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 5cf12e7..8a0efac 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3190,9 +3190,14 @@ 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;
 	}
 
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