Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754324Ab0LIQoP (ORCPT ); Thu, 9 Dec 2010 11:44:15 -0500 Received: from mail-pv0-f174.google.com ([74.125.83.174]:42718 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753088Ab0LIQoO (ORCPT ); Thu, 9 Dec 2010 11:44:14 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=FxfWITi4SRePEIiqLR0waN264WlKd7OtcXebwO4aIIrN9n2hcpssFwSerBuCqjlymc MFAZ5LPHVt3Vz1He8OMshaS2cUFB7Orfq9tMyxr6m7JKTDEb/KdMkTlRaQ0SzGlMyL40 nzDSE6tcim7RSv1/N2paz0z+273/iwKvtUfbU= Date: Fri, 10 Dec 2010 00:47:48 +0800 From: =?utf-8?Q?Am=C3=A9rico?= Wang To: Oleg Nesterov Cc: Florian Mickler , Ingo Molnar , =?utf-8?Q?Am=C3=A9rico?= Wang , Dave Chinner , Eric Dumazet , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [regression, 2.6.37-rc1] 'ip link tap0 up' stuck in do_exit() Message-ID: <20101209164748.GA3218@hack> References: <20101103062609.GB31163@dastard> <1288768402.2467.665.camel@edumazet-laptop> <20101103103448.GA9169@dastard> <20101103112936.GB9169@dastard> <20101104002140.GA13830@dastard> <20101104054718.GC5210@cr0.nay.redhat.com> <20101208100245.01cf23c5@schatten.dmk.lab> <20101208134116.GA16923@redhat.com> <20101208134712.GB16923@redhat.com> <20101208140822.GA18681@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101208140822.GA18681@redhat.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1850 Lines: 49 On Wed, Dec 08, 2010 at 03:08:22PM +0100, Oleg Nesterov wrote: >On 12/08, Oleg Nesterov wrote: >> >> On 12/08, Oleg Nesterov wrote: >> > >> > On 12/08, Florian Mickler wrote: >> > > >> > > [ ccing Ingo and Oleg ] as suggested >> > >> > Well. Of course I can't explain this bug. But, looking at this email >> > I do not see amything strange in exit/schedule/etc. >> > >> > > > >> > > > This is resulting in the command 'ip link set tap0 up' hanging as a zombie: >> > > > >> > > > >> > > > >> > > > root 3005 1 0 16:53 pts/3 00:00:00 /bin/sh /vm-images/qemu-ifup tap0 >> > > > >> > > > root 3011 3005 0 16:53 pts/3 00:00:00 /usr/bin/sudo /sbin/ip link set tap0 up >> > > > >> > > > root 3012 3011 0 16:53 pts/3 00:00:00 [ip] >> > >> > That is. ip is a zombie. >> >> And. I do not know if this matters or not, but "the command 'ip link >> set tap0 up' hanging as a zombie" does not look right. >> >> This was spawned by >> >> > >> > > > if [ -n "$1" ];then >> > >> > > > /usr/bin/sudo /sbin/ip link set $1 up >> > >> > > > sleep 0.5s >> > >> > > > /usr/bin/sudo /usr/sbin/brctl addif $switch $1 >> > >> > > > exit 0 >> > >> > > > fi >> >> The command does not hang. But it forks the child with pid == 3012, >> this child exits. > >Damn, sorry for noise, forgot to mention... > >The parent's trace (pid == 3011) can be more useful. Say, if it >hangs in do_wait(), then the kernel is obviously wrong. > Yeah, there is no point that a zombie can trigger a BUG_ON in kenrel. But it is still interesting to know why it becomes a zombie... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/