From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: network packet corruption in v3.6.0-rc1 (and also in v3.5) Date: Sun, 19 Aug 2012 13:02:14 +0200 Message-ID: <1345374134.5158.103.camel@edumazet-glaptop> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Alexey Kuznetsov , James Morris , netdev@vger.kernel.org To: Andrew Worsley Return-path: Received: from mail-wg0-f44.google.com ([74.125.82.44]:59553 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752092Ab2HSLCT (ORCPT ); Sun, 19 Aug 2012 07:02:19 -0400 Received: by wgbdr13 with SMTP id dr13so4581328wgb.1 for ; Sun, 19 Aug 2012 04:02:18 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Sat, 2012-08-18 at 16:40 +1000, Andrew Worsley wrote: > Some times I get a burst of errors and dropped tcp connections with > this warning. I had a similar issue with v3.5 (in fact v3.5 was > unusable for https connections which would give bad MAC code messages > at the application level).. > > The issue seems better under v3.6-rc1 where as it was very bad under > v3.5. Let me know if there is something I can do to avoid this > problem. I am using the USB r8712u wireless NIC if that is relevant as > I haven't been able to get the native wireless working under the MAC > book yet (requires proprietary firmware extraction which I am not > familiar with) > > Much obliged if there is anything I can do to avoid it as it is rather > annoying. Doesn't happen at all with my Debian wheezy 3.2.0-2-amd64 > kernel. OK, this seems to be related to r8712u, still in staging tree. At first glance, its using a buggy skb_clone(), or kind of a 'reuse skb' trick I have no time to investigate. I suspect that some memory area are overwritten by this driver, and this was not noticed with older kernels. With new kernels, its triggering a WARN_ON() in tcp stack. Any chance you can try to reproduce the bug with another adapter ?