From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: TCP-MD5 checksum failure on x86_64 SMP Date: Tue, 4 May 2010 09:12:15 -0700 Message-ID: <20100504091215.5a4a51f4@nehalam> References: <1272972722.2097.1.camel@achroite.uk.solarflarecom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Ben Hutchings , netdev@vger.kernel.org To: Bhaskar Dutta Return-path: Received: from mail.vyatta.com ([76.74.103.46]:35498 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932282Ab0EDQMT convert rfc822-to-8bit (ORCPT ); Tue, 4 May 2010 12:12:19 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 4 May 2010 19:58:32 +0530 Bhaskar Dutta wrote: > On Tue, May 4, 2010 at 5:02 PM, Ben Hutchings wrote: > > On Tue, 2010-05-04 at 09:00 +0530, Bhaskar Dutta wrote: > >> Hi, > >> > >> I am observing intermittent TCP-MD5 checksum failures > >> (CONFIG_TCP_MD5SIG) =A0on kernel 2.6.31 while talking to a BGP rou= ter. > >> > >> The problem is only seen in multi-core 64 bit machines. > >> Is there any known bug in the per_cpu_ptr implementation (I am awa= re > >> that the percpu allocator has been re-implemented in 2.6.33) that > >> might cause a corruption in 64 bit SMP machines? > >> > >> Any pointers would be appreciated. > > > > There was another recent report of incorrect MD5 signatures in > > , but without a= ny > > response. > > > > Ben. > > >=20 > I found another thread posted back in Jan 2007 with a similar bug > (x86_64 on 2.6.20) but no replies to that as well. > http://lkml.org/lkml/2007/1/20/56 2.6.20 had lots of other MD5 bugs. Your problem might be related to GRO. MD5 may not handle multi-fragment packets.