From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756234Ab2DQPw5 (ORCPT ); Tue, 17 Apr 2012 11:52:57 -0400 Received: from mail.vyatta.com ([76.74.103.46]:34019 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755991Ab2DQPwz (ORCPT ); Tue, 17 Apr 2012 11:52:55 -0400 Date: Tue, 17 Apr 2012 08:52:48 -0700 From: Stephen Hemminger To: "Peter Huang (Peng)" Cc: "'David S. Miller'" , netdev@vger.kernel.org, eric.dumazet@gmail.com, linux-kernel@vger.kernel.org, ctrix+debianbugs@navynet.it, peter.huangpeng@gmail.com, harry.majun@huawei.com Subject: Re: [PATCH] set fake_rtable's dst to NULL to avoid kernel Oops. Message-ID: <20120417085248.3e642294@nehalam.linuxnetplumber.net> In-Reply-To: <000001cd1c62$75d10de0$617329a0$%huangpeng@huawei.com> References: <000001cd1c62$75d10de0$617329a0$%huangpeng@huawei.com> Organization: Vyatta X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Apr 2012 14:22:26 +0800 "Peter Huang (Peng)" wrote: > When bridge is deleted before tap/vif device's delete, kernel may encounter an oops because of NULL reference to fake_rtable's dst. > Set fake_rtable's dst to NULL before sending packets out can solve this problem. > > > Acked-by: Eric Dumazet > Signed-off-by: Peter Huang > --- > include/linux/netfilter_bridge.h | 8 ++++++++ > net/bridge/br_forward.c | 1 + > net/bridge/br_netfilter.c | 6 +----- > 3 files changed, 10 insertions(+), 5 deletions(-) > > diff --git a/include/linux/netfilter_bridge.h b/include/linux/netfilter_bridge.h > index 0ddd161..70744fe 100644 > --- a/include/linux/netfilter_bridge.h > +++ b/include/linux/netfilter_bridge.h > @@ -104,9 +104,17 @@ struct bridge_skb_cb { > } daddr; > }; > > +static inline void br_drop_fake_rtable(struct sk_buff *skb) { > + struct dst_entry *dst = skb_dst(skb); > + /* abuse fact that only fake_rtable has DST_NOPEER set */ > + if (dst && (dst->flags & DST_NOPEER)) > + skb_dst_drop(skb); > +} This check seems like a disaster waiting to happen when the next change to DST table happens.