From: Jarek Poplawski <jarkao2@o2.pl>
Date: Thu, 22 Mar 2007 08:11:26 +0000 (-0800)
Subject: [PATCH] lockdep: lockdep_depth vs. debug_locks
X-Git-Tag: v2.6.21-rc5~35
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e3a55fd18deab758a2970e0dfcd60a677a920426;p=linux-2.6

[PATCH] lockdep: lockdep_depth vs. debug_locks

lockdep found a bug during a run of workqueue function - this could be also
caused by a bug from other code running simultaneously.

lockdep really shouldn't be used when debug_locks == 0!

Reported-by: Folkert van Heusden <folkert@vanheusden.com>
Inspired-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 06fe93a3e9..14c937d345 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -245,7 +245,7 @@ extern void lock_release(struct lockdep_map *lock, int nested,
 
 # define INIT_LOCKDEP				.lockdep_recursion = 0,
 
-#define lockdep_depth(tsk)	((tsk)->lockdep_depth)
+#define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)
 
 #else /* !LOCKDEP */