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Subject: Re: [RFC PATCH 4/4] lockdep: fix race condition in
 __lock_set_class()
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Yong Zhang <yong.zhang0@gmail.com>
Cc: linux-kernel@vger.kernel.org, sergey.senozhatsky@gmail.com, bp@alien8.de,
        Ingo Molnar <mingo@elte.hu>
Date: Mon, 07 Nov 2011 13:30:54 +0100
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References: <1320398790-21663-1-git-send-email-yong.zhang0@gmail.com>
	 <1320398790-21663-5-git-send-email-yong.zhang0@gmail.com>
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On Fri, 2011-11-04 at 17:26 +0800, Yong Zhang wrote:
> When someone call lock_set_class() with valid key, nothing
> protect the initializing of 'lockdep_map'; thus could lead
> to flase positive warning from lockdep (such as "key not in
> .data!"). This patch cure that potential issue.

How? that warning is triggered of the lock_class_key * passed into
lockdep_init_map and is unrelated to the actual content of the
lockdep_map.