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From: Sasha Levin <levinsasha928@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org,
	yoshfuji@linux-ipv6.org, Patrick McHardy <kaber@trash.net>,
	netdev@vger.kernel.org,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>, Dave Jones <davej@redhat.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Subject: Re: ipv6: tunnel: hang when destroying ipv6 tunnel
Date: Sat, 31 Mar 2012 23:43:19 +0200	[thread overview]
Message-ID: <CA+1xoqcAXyh306=2=QKWyM3BE44=MT+nsuRQn5YLOLgbtZqicA@mail.gmail.com> (raw)
In-Reply-To: <20120331213423.GA21219@redhat.com>

On Sat, Mar 31, 2012 at 11:34 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> On 03/31, Eric Dumazet wrote:
>>
>> On Sat, 2012-03-31 at 19:51 +0200, Sasha Levin wrote:
>> > Hi all,
>> >
>> > It appears that a hang may occur when destroying an ipv6 tunnel, which
>> > I've reproduced several times in a KVM vm.
>
> kernel version?

latest linux-next

>> > [ 1561.564172] INFO: task kworker/u:2:3140 blocked for more than 120 seconds.
>
> And nobody else?

Some more messages follow a bit later which get stuck in vfs related code.

> It would be nice to know what sysrq-t says, in particular the trace
> of khelper thread is interesting.

Sure, I'll get one when it happens again.

>> Something is wrong here, call_usermodehelper_exec ( ... UMH_WAIT_EXEC)
>> should not block forever.
>
> Yes, unless it triggers another request_module()...
>
> Tetsuo, could you please take a look? Unlikely, but may be this
> is fixed by your kmod-avoid-deadlock-by-recursive-kmod-call.patch
> in -mm ?
>
> Oleg.
>

  reply	other threads:[~2012-03-31 21:43 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-31 17:51 ipv6: tunnel: hang when destroying ipv6 tunnel Sasha Levin
2012-03-31 20:59 ` Eric Dumazet
2012-03-31 21:34   ` Oleg Nesterov
2012-03-31 21:43     ` Sasha Levin [this message]
2012-03-31 23:26       ` Sasha Levin
2012-04-01  3:21         ` Tetsuo Handa
2012-04-01 17:33           ` Sasha Levin
2012-04-05 14:29             ` Tetsuo Handa
2012-04-05 14:34               ` Tetsuo Handa
2012-04-06 11:44               ` Tetsuo Handa
2012-04-06 18:09                 ` Jim Garlick
2012-04-07  0:06                   ` Tetsuo Handa
2012-04-11 12:20                     ` Sasha Levin
2012-04-01  5:07         ` Eric Dumazet
2012-04-01 16:38         ` Oleg Nesterov

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