From: David Miller <davem@davemloft.net>
To: nite@hq.alert.sk
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] fix CONFIG_TCP_MD5SIG + CONFIG_PREEMPT timer BUG()
Date: Tue, 15 Sep 2009 23:49:42 -0700 (PDT) [thread overview]
Message-ID: <20090915.234942.49864006.davem@davemloft.net> (raw)
In-Reply-To: <20090915230126.GA21539@hq.alert.sk>
From: Robert Varga <nite@hq.alert.sk>
Date: Wed, 16 Sep 2009 01:01:26 +0200
> Hi,
>
> I have recently came across a preemption imbalance detected by:
>
> <4>huh, entered ffffffff80644630 with preempt_count 00000102, exited with 00000101?
> <0>------------[ cut here ]------------
> <2>kernel BUG at /usr/src/linux/kernel/timer.c:664!
> <0>invalid opcode: 0000 [1] PREEMPT SMP
>
> with ffffffff80644630 being inet_twdr_hangman().
>
> This appeared after I enabled CONFIG_TCP_MD5SIG and played with it a
> bit, so I looked at what might have caused it.
>
> One thing that struck me as strange is tcp_twsk_destructor(), as it
> calls tcp_put_md5sig_pool() -- which entails a put_cpu(), causing the
> detected imbalance. Found on 2.6.23.9, but 2.6.31 is affected as well,
> as far as I can tell.
>
> Signed-off-by: Robert Varga <nite@hq.alert.sk>
Looks good, applied and queued up for stable.
Thanks!
prev parent reply other threads:[~2009-09-16 6:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-15 23:01 [PATCH] fix CONFIG_TCP_MD5SIG + CONFIG_PREEMPT timer BUG() Robert Varga
2009-09-16 6:49 ` David Miller [this message]
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