From: Simon Kirby <sim@hostway.ca>
To: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: 3.3.0, 3.4-rc1 reproducible tun Oops
Date: Tue, 17 Apr 2012 11:35:28 -0700 [thread overview]
Message-ID: <20120417183528.GA32726@hostway.ca> (raw)
In-Reply-To: <4F8D5FAD.10304@parallels.com>
On Tue, Apr 17, 2012 at 04:18:53PM +0400, Stanislav Kinsbursky wrote:
> 17.04.2012 06:08, Simon Kirby ??????????:
> >On Thu, Apr 05, 2012 at 04:41:04AM +0200, Eric Dumazet wrote:
> >
> >>Hmm, is it happening if you remove the nvidia module ?
> >>
> >>If yes, please try to add slub_debug=FZPU
> >
> >Finally got annoyed enough at this to bisect it. It doesn't happen every
> >time and I got a bit confused, but I finally tracked it down to:
> >
> >1ab5ecb90cb6a3df1476e052f76a6e8f6511cb3d is the first bad commit
> >commit 1ab5ecb90cb6a3df1476e052f76a6e8f6511cb3d
> >Author: Stanislav Kinsbursky<skinsbursky@parallels.com>
> >Date: Mon Mar 12 02:59:41 2012 +0000
> >
> > tun: don't hold network namespace by tun sockets
> >
> > v3: added previously removed sock_put() to the tun_release() callback, because
> > sk_release_kernel() doesn't drop the socket reference.
> >
> > v2: sk_release_kernel() used for socket release. Dummy tun_release() is
> > required for sk_release_kernel() ---> sock_release() ---> sock->ops->release()
> > call.
> >
> > TUN was designed to destroy it's socket on network namesapce shutdown. But this
> > will never happen for persistent device, because it's socket holds network
> > namespace.
> > This patch removes of holding network namespace by TUN socket and replaces it
> > by creating socket in init_net and then changing it's net it to desired one. On
> > shutdown socket is moved back to init_net prior to final put.
> >
> > Signed-off-by: Stanislav Kinsbursky<skinsbursky@parallels.com>
> > Signed-off-by: David S. Miller<davem@davemloft.net>
> >
> >...With this reverted on top of 3.4-rc3, I no longer see crashes when I
> >keep making and breaking the SSH tunnel while running "vmstat 1" in an
> >SSH session over a socket that is running through that tunnel.
> >
> >Simon-
>
> Hi, Simon.
> Could you please try to apply the patch below on top of your the
> tree (with 1ab5ecb90cb6a3df1476e052f76a6e8f6511cb3d applied) and
> check does it fix the problem:
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index bb8c72c..1fc4622 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1540,13 +1540,10 @@ static int tun_chr_close(struct inode
> *inode, struct file *file)
> if (dev->reg_state == NETREG_REGISTERED)
> unregister_netdevice(dev);
> rtnl_unlock();
> - }
> + } else
> + sock_put(tun->socket.sk);
> }
>
> - tun = tfile->tun;
> - if (tun)
> - sock_put(tun->socket.sk);
> -
> put_net(tfile->net);
> kfree(tfile);
(Whitespace-damaged patch, applied manually)
Yes, I no longer see crashes with this applied. I haven't tried with
kmemleak or similar, but it seems to work.
Thanks,
Simon-
next prev parent reply other threads:[~2012-04-17 18:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-04 22:05 3.3.0, 3.4-rc1 reproducible tun Oops Simon Kirby
2012-04-05 2:41 ` Eric Dumazet
2012-04-05 5:58 ` Simon Kirby
2012-04-17 2:08 ` Simon Kirby
2012-04-17 12:18 ` Stanislav Kinsbursky
2012-04-17 18:35 ` Simon Kirby [this message]
2012-04-17 18:49 ` Stanislav Kinsbursky
2012-04-18 2:38 ` David Miller
2012-04-18 11:32 ` Stanislav Kinsbursky
2012-05-19 1:07 ` Simon Kirby
2012-05-21 14:51 ` Stanislav Kinsbursky
2012-04-18 6:51 Stanislav Kinsbursky
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