From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752561AbZBQJEU (ORCPT ); Tue, 17 Feb 2009 04:04:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751182AbZBQJEB (ORCPT ); Tue, 17 Feb 2009 04:04:01 -0500 Received: from stinky.trash.net ([213.144.137.162]:50263 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751092AbZBQJD7 (ORCPT ); Tue, 17 Feb 2009 04:03:59 -0500 Message-ID: <499A7D7D.1090607@trash.net> Date: Tue, 17 Feb 2009 10:03:57 +0100 From: Patrick McHardy User-Agent: Mozilla-Thunderbird 2.0.0.19 (X11/20090103) MIME-Version: 1.0 To: Jarek Poplawski CC: Karl Hiramoto , netdev@vger.kernel.org, netfilter@vger.kernel.org, LKML Subject: Re: problem with IPoA (CLIP), NAT, and VLANS References: <20090216232016.GA4803@ami.dom.local> In-Reply-To: <20090216232016.GA4803@ami.dom.local> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jarek Poplawski wrote: > Very nice debugging, but I think your patch doesn't look like enough: > 1) it skips copy for cloned skbs, > 2) this skb_cow_head() is needed anyway, sometimes. > So the real bug should be found in skb_cow_head() or elsewhere. > > I attach here 2 patches for testing: > 1) skb->mac_header update: it looks like needed, but I don't know if > it matters here, > 2) an extention of your patch but with pskb_expand_head() called for > one to one copy. > > BTW, if it's not a big problem it would be nice to try this e.g. on > 2.6.29-rc5. The first patch looks fine. As for the second one, I would like to understand why we're seing these packets. The VLAN driver uses the original headroom plus the space it needs itself, which suggests that the underlying driver specifies an incorrect headroom. The driver doesn't appear to be part of the mainline kernel though.