From patchwork Tue May 10 18:05:40 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Noah Meyerhans X-Patchwork-Id: 95020 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id B0047B6F00 for ; Wed, 11 May 2011 04:10:06 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751496Ab1EJSFv (ORCPT ); Tue, 10 May 2011 14:05:51 -0400 Received: from minas.morgul.net ([128.31.0.48]:52560 "EHLO minas.morgul.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751499Ab1EJSFp (ORCPT ); Tue, 10 May 2011 14:05:45 -0400 Received: from frodo by minas.morgul.net with local (Exim 4.69) (envelope-from ) id 1QJrJU-0003GW-Kw; Tue, 10 May 2011 14:05:40 -0400 Date: Tue, 10 May 2011 11:05:40 -0700 From: Noah Meyerhans To: Ben Hutchings Cc: 625914@bugs.debian.org, netdev , bridge@lists.linux-foundation.org Subject: Re: Bug#625914: linux-image-2.6.38-2-amd64: bridging is not interacting well with multicast in 2.6.38-4 Message-ID: <20110510180540.GI6397@morgul.net> References: <20110506201234.6297.70279.reportbug@ip6-localhost> <1304995124.4065.157.camel@localhost> <20110510043833.GG6397@morgul.net> <1305031369.4065.259.camel@localhost> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1305031369.4065.259.camel@localhost> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, May 10, 2011 at 01:42:49PM +0100, Ben Hutchings wrote: > > > This is pretty weird. Debian version 2.6.38-3 has a few bridging > > > changes from stable 2.6.38.3 and 2.6.38.4, but they don't look like they > > > would cause this. > > > > I have apparently filed the bug against the wrong version of Debian's > > kernel. 2.6.38-3 is not affected, and works as expected. The change > > was introduced in -4. That may have been clear from the report itself, > > but the report was filed against -3. I've fixed that in the BTS. > > I gathered that, and then made the same mistake in writing the above! > The version with the regression, 2.6.38-4, includes the changes from > stable 2.6.38.3 and 2.6.38.4 With a little help from git bisect, I've tracked this regression down to the following commit to the stable-2.6.38.y tree: commit 5f1c356a3fadc0c19922d660da723b79bcc9aad7 Author: Herbert Xu Date: Fri Mar 18 05:27:28 2011 +0000 bridge: Reset IPCB when entering IP stack on NF_FORWARD [ Upstream commit 6b1e960fdbd75dcd9bcc3ba5ff8898ff1ad30b6e ] Whenever we enter the IP stack proper from bridge netfilter we need to ensure that the skb is in a form the IP stack expects it to be in. The entry point on NF_FORWARD did not meet the requirements of the IP stack, therefore leading to potential crashes/panics. This patch fixes the problem. Signed-off-by: Herbert Xu Acked-by: Stephen Hemminger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman The diff is nf_bridge->physoutdev = skb->dev; If I revert this change, network connectivity functions as expected for the VMs on this host. I don't know enough about this change or the problem it was supposed to solve to be able to guess about what's going wrong. noah diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index 4b5b66d..49d50ea 100644 --- a/net/bridge/br_netfilter.c +++ b/net/bridge/br_netfilter.c @@ -741,6 +741,9 @@ static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff *skb, nf_bridge->mask |= BRNF_PKT_TYPE; } + if (br_parse_ip_options(skb)) + return NF_DROP; + /* The physdev module checks on this */ nf_bridge->mask |= BRNF_BRIDGED;