Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753804Ab0KCHNa (ORCPT ); Wed, 3 Nov 2010 03:13:30 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:63733 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753186Ab0KCHN2 (ORCPT ); Wed, 3 Nov 2010 03:13:28 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=ghY51gTxiNxNmOw4xifXj88h+9LAo0g0XW7IriXiz9mkjCaU+3Ze/nuU76BrUJR5W/ o0iN6hmoiiDOoA56fPVP1BiwzBIy36aXW4/OpGztvfbm+klCysoArT3t29GIJDD+hN0Y T/vNe9XuqN0pGyR1iosiD3zYTAFyfhHDoyHE4= Subject: Re: [regression, 2.6.37-rc1] 'ip link tap0 up' stuck in do_exit() From: Eric Dumazet To: Dave Chinner Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org In-Reply-To: <20101103062609.GB31163@dastard> References: <20101103062609.GB31163@dastard> Content-Type: text/plain; charset="UTF-8" Date: Wed, 03 Nov 2010 08:13:22 +0100 Message-ID: <1288768402.2467.665.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2873 Lines: 80 Le mercredi 03 novembre 2010 à 17:26 +1100, Dave Chinner a écrit : > Folks, > > Starting up KVM on a current mainline kernel using the tap > device for the networking is resulting in the ip process tryin gto > up the tap interface hanging. KVM is started with this networking > config: > > .... > -net nic,vlan=0,macaddr=00:e4:b6:63:63:6d,model=virtio \ > -net tap,vlan=0,script=/vm-images/qemu-ifup,downscript=no \ > .... > > And the script is effectively: > > switch=br0 > 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 > exit 1 > > 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] > > In do_exit() with this trace: > > [ 1630.782255] ip x ffff88063fcb3600 0 3012 3011 0x00000000 > [ 1630.789121] ffff880631328000 0000000000000046 0000000000000000 ffff880633104380 > [ 1630.796524] 0000000000013600 ffff88062f031fd8 0000000000013600 0000000000013600 > [ 1630.803925] ffff8806313282d8 ffff8806313282e0 ffff880631328000 0000000000013600 > [ 1630.811324] Call Trace: > [ 1630.813760] [] ? do_exit+0x716/0x724 > [ 1630.818964] [] ? do_group_exit+0x7a/0xa4 > [ 1630.824512] [] ? sys_exit_group+0x12/0x16 > [ 1630.830149] [] ? system_call_fastpath+0x16/0x1b > > The address comes down to the schedule() call: > > (gdb) l *(do_exit+0x716) > 0xffffffff8104a90d is in do_exit (kernel/exit.c:1034). > 1029 preempt_disable(); > 1030 exit_rcu(); > 1031 /* causes final put_task_struct in finish_task_switch(). */ > 1032 tsk->state = TASK_DEAD; > 1033 schedule(); > 1034 BUG(); > 1035 /* Avoid "noreturn function does return". */ > 1036 for (;;) > 1037 cpu_relax(); /* For when BUG is null */ > 1038 } > > Needless to say, KVM is not starting up. This works just fine on > 2.6.35.1 and so is a regression. I can't do a lot of testing on this as > the host is the machine that hosts all my build and test environments.... > > Cheers, > > Dave. Could it be the same problem than http://kerneltrap.com/mailarchive/linux-netdev/2010/10/23/6288128 Try to revert bee31369ce16fc3898ec9a54161248c9eddb06bc ? Thanks -- 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/