Date: Tue, 5 Sep 2006 15:03:56 +0200
From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
       Arjan van de Ven <arjan@infradead.org>,
       Daniel Walker <dwalker@mvista.com>, Hua Zhong <hzhong@gmail.com>
Subject: lockdep oddity
Message-ID: <20060905130356.GB6940@osiris.boeblingen.de.ibm.com>
References: <20060901015818.42767813.akpm@osdl.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20060901015818.42767813.akpm@osdl.org>
User-Agent: mutt-ng/devel-r804 (Linux)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1102
Lines: 30

The lock validator gives me this (latest -mm and 2.6.18-rc6):

===================================== 
[ BUG: bad unlock balance detected! ] 
------------------------------------- 
swapper/0 is trying to release lock (resource_lock) at:
[<0000000000042842>] request_resource+0x52/0x88 
but there are no more locks to release! 

The reason is that the BUILD_LOCK_OPS macros in kernel/lockdep.c don't contain
any of the *_acquire calls, while all of the _unlock functions contain a
*_release call. Hence I get immediately unbalanced locks.

CONFIG_PREEMPT,
CONFIG_SMP,
!CONFIG_PROVE_LOCKING,
CONFIG_DEBUG_LOCK_ALLOC,
and
CONFIG_LOCKDEP

will generate this code.

Found this will debugging some random memory corruptions that happen when
CONFIG_PROVE_LOCKING and CONFIG_PROFILE_LIKELY are both on.
Switching both off or having only one of them on seems to work.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/