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Subject: Re: [PATCH 1/4] lockdep: lock_set_subclass() fix
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Yong Zhang <yong.zhang0@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>, linux-kernel@vger.kernel.org,
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        Ingo Molnar <mingo@elte.hu>, Tejun Heo <tj@kernel.org>,
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Date: Tue, 08 Nov 2011 09:46:20 +0100
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On Tue, 2011-11-08 at 16:14 +0800, Yong Zhang wrote:
> 
> But how do we deal with ->class_cache? Always set it in
> loop_up_lock_class()? 

Hrm.. good point, aside from that there's another problem as well, I
think we can deal with the cache being NULL, but is memset() an atomic
write? If not a read could observe an intermediate state and go funny.

I'm tempted to go with the pure kmemcheck_mark_initialized() thing for
now.