From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id E70872A5F for ; Mon, 25 Jul 2016 17:28:50 +0200 (CEST) Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2E52F85542; Mon, 25 Jul 2016 15:28:50 +0000 (UTC) Received: from [10.36.4.65] (vpn1-4-65.ams2.redhat.com [10.36.4.65]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u6PFSlOP026037 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 25 Jul 2016 11:28:49 -0400 To: Yuanhan Liu References: <1469455798-19790-1-git-send-email-maxime.coquelin@redhat.com> <20160725152412.GS28708@yliu-dev.sh.intel.com> Cc: huawei.xie@intel.com, dev@dpdk.org, Thomas Monjalon From: Maxime Coquelin Message-ID: Date: Mon, 25 Jul 2016 17:28:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <20160725152412.GS28708@yliu-dev.sh.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 25 Jul 2016 15:28:50 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH] vhost: fix off-by-one error on nr_desc check X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Jul 2016 15:28:51 -0000 On 07/25/2016 05:24 PM, Yuanhan Liu wrote: > On Mon, Jul 25, 2016 at 04:09:58PM +0200, Maxime Coquelin wrote: >> nr_desc is not an index but the number of descriptors, >> so can be equal to the virtqueue size. >> >> Fixes: a436f53ebfeb ("vhost: avoid dead loop chain") >> >> Cc: Yuanhan Liu >> Signed-off-by: Maxime Coquelin > > Thanks for catching it! > >> --- >> Hi Yuanhan, >> >> I faced the bug while testing my indirect descriptor patch, it happens >> as soon as the number of chained descritors is above 2. >> >> But the bug may in theory also be faced with normal descriptors, > > In theory, yes, and only in one case, that there is a Tx has 256 > descriptors chained. If that happens, I doubt things work well. > So I would say it just happens __in theory__. Right. > >> so it might >> be good to have it 16.07? > > Even though, it apparently fixes a bug, so I think we could have it > for 16.07. Good, but don't delay 16.07 for that! :) > > Acked-by: Yuanhan Liu > > --yliu > Thanks, Maxime