From: "Américo Wang" <xiyou.wangcong@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: "Florian Mickler" <florian@mickler.org>,
"Ingo Molnar" <mingo@elte.hu>,
"Américo Wang" <xiyou.wangcong@gmail.com>,
"Dave Chinner" <david@fromorbit.com>,
"Eric Dumazet" <eric.dumazet@gmail.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [regression, 2.6.37-rc1] 'ip link tap0 up' stuck in do_exit()
Date: Fri, 10 Dec 2010 00:47:48 +0800 [thread overview]
Message-ID: <20101209164748.GA3218@hack> (raw)
In-Reply-To: <20101208140822.GA18681@redhat.com>
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] <defunct>
>> >
>> > 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...
next prev parent reply other threads:[~2010-12-09 16:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-03 6:26 [regression, 2.6.37-rc1] 'ip link tap0 up' stuck in do_exit() Dave Chinner
2010-11-03 7:13 ` Eric Dumazet
2010-11-03 10:34 ` Dave Chinner
2010-11-03 11:29 ` Dave Chinner
2010-11-04 0:21 ` Dave Chinner
2010-11-04 5:47 ` Américo Wang
2010-12-08 9:02 ` Florian Mickler
2010-12-08 13:41 ` Oleg Nesterov
2010-12-08 13:47 ` Oleg Nesterov
2010-12-08 14:08 ` Oleg Nesterov
2010-12-09 16:47 ` Américo Wang [this message]
2010-12-09 17:07 ` Eric Dumazet
2010-12-09 17:09 ` Eric Dumazet
2010-12-09 17:59 ` Jim Bos
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