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From: David Miller <davem@davemloft.net>
Subject: Re: PATCH] filter: fix sk_filter rcu handling
Date: Mon, 06 Dec 2010 09:29:59 -0800 (PST)
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 05 Dec 2010 21:53:52 +0100

> [PATCH] filter: fix sk_filter rcu handling
> 
> Pavel Emelyanov tried to fix a race between sk_filter_(de|at)tach and
> sk_clone() in commit 47e958eac280c263397
> 
> Problem is we can have several clones sharing a common sk_filter, and
> these clones might want to sk_filter_attach() their own filters at the
> same time, and can overwrite old_filter->rcu, corrupting RCU queues.
> 
> We can not use filter->rcu without being sure no other thread could do
> the same thing.
> 
> Switch code to a more conventional ref-counting technique : Do the
> atomic decrement immediately and queue one rcu call back when last
> reference is released.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied, and queued up for -stable, thanks.