Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757975Ab1CBEvn (ORCPT ); Tue, 1 Mar 2011 23:51:43 -0500 Received: from mail4.comsite.net ([205.238.176.238]:15421 "EHLO mail4.comsite.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757959Ab1CBEvm (ORCPT ); Tue, 1 Mar 2011 23:51:42 -0500 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=127.0.0.1; From: "miltonm" Reply-to: miltonm@bga.com To: Ben Hutchings , Greg KH Cc: linux-kernel@vger.kernel.org, stable@kernel.org, Don Skidmore , Milton Miller , "David S. Miller" , Anton Blanchard , akpm@linux-foundation.org, torvalds@linux-foundation.org, stable-review@kernel.org, alan@lxorguk.ukuu.org.uk, Jeff Kirsher Subject: Re: [Stable-review] [22/68] ixgbe: prevent speculative processing of descriptors before ready X-Mailer: Quality Web Email v3.1t X-Originating-IP: 71.22.127.106 Date: Tue, 01 Mar 2011 22:51:17 -0600 Message-id: <4d6dccc5.3c4.4db0.1082106294@bga.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Authenticated-User: miltonm@bga.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2018 Lines: 51 ----- Original Message Follows ----- From: Ben Hutchings To: Greg KH Cc: linux-kernel@vger.kernel.org, stable@kernel.org, Don Skidmore , Milton Miller , "David S. Miller" , Anton Blanchard , akpm@linux-foundation.org, torvalds@linux-foundation.org, stable-review@kernel.org, alan@lxorguk.ukuu.org.uk, Jeff Kirsher Subject: Re: [Stable-review] [22/68] ixgbe: prevent speculative processing of descriptors before ready Date: Tue, 01 Mar 2011 02:14:33 +0000 > On Mon, 2011-02-28 at 08:22 -0800, Greg KH wrote: > > 2.6.32-longterm review patch. If anyone has any > > objections, please let us know. > > ------------------ > > > > From: Milton Miller > > > > commit 3c945e5b3719bcc18c6ddd31bbcae8ef94f3d19a > > upstream. > > The PowerPC architecture does not require loads to > > independent bytes to be ordered without adding an > > explicit barrier. > > In ixgbe_clean_rx_irq we load the status bit then load > > the packet data. With packet split disabled if these > > loads go out of order we get a stale packet, but we will > > notice the bad sequence numbers and drop it. > > The problem occurs with packet split enabled where the > > TCP/IP header and data are in different descriptors. If > > the reads go out of order we may have data that doesn't > match the TCP/IP header. Since we use hardware > > checksumming this bad data is never verified and it > makes it all the way to the application. [...] > > Packet splitting should be completely disabled on the > 82599, anyway. Greg, what happened to this patch: This was initially observed on 82598 and is still needed there. milton -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/