From: Herbert Xu <herbert@gondor.apana.org.au>
To: akpm@linux-foundation.org (Andrew Morton)
Subject: Re: Deadlock after info soft-safe -> soft-unsafe lock order detected
Cc: zdenek.kabelac@gmail.com, linux-kernel@vger.kernel.org,
       netdev@vger.kernel.org, dada1@cosmosbay.com
Organization: Core
In-Reply-To: <20090105201811.00242be7.akpm@linux-foundation.org>
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Message-Id: <E1LKXMF-0006fe-DK@gondolin.me.apana.org.au>
Date: Wed, 07 Jan 2009 23:17:59 +1100
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Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> I'd be suspecting the percpu counter work in TCP?

This is the bogus lockdep output which is fixed by

commit ea319518ba3de282c13ae1cf4bf2215c5e03e67e
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date:   Fri Dec 26 15:08:55 2008 +0100

    locking, percpu counters: introduce separate lock classes
    
    Impact: fix lockdep false positives
    
    Classify percpu_counter instances similar to regular lock objects --
    that is, per instantiation site.
    
    The networking code has increased its use of percpu_counters, which
    leads to false positives if they are treated as a single class.
    
    Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>

It was only pulled very recently despite the Dec 26 date.

Cheers,
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Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
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