From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v2 net] xen-netback: make sure that hashes are not send to unaware frontends Date: Fri, 07 Oct 2016 23:53:15 -0400 (EDT) Message-ID: <20161007.235315.1445609703306777270.davem@davemloft.net> References: <1475829151-3707-1-git-send-email-paul.durrant@citrix.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, xen-devl@lists.xenproject.org, wei.liu2@citrix.com To: paul.durrant@citrix.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:59960 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757434AbcJHDxT (ORCPT ); Fri, 7 Oct 2016 23:53:19 -0400 In-Reply-To: <1475829151-3707-1-git-send-email-paul.durrant@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Paul Durrant Date: Fri, 7 Oct 2016 09:32:31 +0100 > In the case when a frontend only negotiates a single queue with xen- > netback it is possible for a skbuff with a s/w hash to result in a > hash extra_info segment being sent to the frontend even when no hash > algorithm has been configured. (The ndo_select_queue() entry point makes > sure the hash is not set if no algorithm is configured, but this entry > point is not called when there is only a single queue). This can result > in a frontend that is unable to handle extra_info segments being given > such a segment, causing it to crash. > > This patch fixes the problem by clearing the hash in ndo_start_xmit() > instead, which is clearly guaranteed to be called irrespective of the > number of queues. > > Signed-off-by: Paul Durrant Applied, thanks.