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Date: Tue, 26 May 2009 14:04:08 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Paul Menage <menage@google.com>
Cc: lizf@cn.fujitsu.com, davem@davemloft.net, tgraf@suug.ch,
       linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH] cls_cgroup: read classid atomically in classifier
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On Tue, 26 May 2009 12:59:11 -0700
Paul Menage <menage@google.com> wrote:

> Avoid reading the unsynchronized value cs->classid multiple times,
> since it could change concurrently from non-zero to zero; this would
> result in the classifier returning a positive result with a bogus
> (zero) classid.

When this race occurs, what are the user-visible consequences?

People who need to decide to which kernels a patch should be applied
like to know such things.