From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757585Ab3FFD1l (ORCPT ); Wed, 5 Jun 2013 23:27:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44401 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756810Ab3FFD1k (ORCPT ); Wed, 5 Jun 2013 23:27:40 -0400 Message-ID: <51B00190.2050307@redhat.com> Date: Thu, 06 Jun 2013 11:27:12 +0800 From: Jason Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: Sergei Shtylyov CC: mst@redhat.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] vhost_net: clear msg.control for non-zerocopy case during tx References: <1370418046-11851-1-git-send-email-jasowang@redhat.com> <51AF40CB.5030101@cogentembedded.com> In-Reply-To: <51AF40CB.5030101@cogentembedded.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/05/2013 09:44 PM, Sergei Shtylyov wrote: > Hello. > > On 05-06-2013 11:40, Jason Wang wrote: > >> When we decide not use zero-copy, msg.control should be set to NULL >> otherwise >> macvtap/tap may set zerocopy callbacks which may decrease the kref of >> ubufs >> wrongly. > >> Bug were introduced by commit cedb9bdce099206290a2bdd02ce47a7b253b6a84 >> (vhost-net: skip head management if no outstanding). > >> This solves the following warnings: > >> WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]() >> Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge >> stp llc openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun] >> CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566 >> Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011 >> ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48 >> ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0 >> ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58 >> Call Trace: >> [] dump_stack+0x19/0x1e >> [] warn_slowpath_common+0x6b/0xa0 >> [] warn_slowpath_null+0x15/0x20 >> [] handle_tx+0x477/0x4b0 [vhost_net] >> [] handle_tx_kick+0x10/0x20 [vhost_net] >> [] vhost_worker+0xfe/0x1a0 [vhost_net] >> [] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net] >> [] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net] >> [] kthread+0xc6/0xd0 >> [] ? kthread_freezable_should_stop+0x70/0x70 >> [] ret_from_fork+0x7c/0xb0 >> [] ? kthread_freezable_should_stop+0x70/0x70 > >> Signed-off-by: Jason Wang >> --- >> drivers/vhost/net.c | 3 ++- >> 1 files changed, 2 insertions(+), 1 deletions(-) > >> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c >> index 2b51e23..b07d96b 100644 >> --- a/drivers/vhost/net.c >> +++ b/drivers/vhost/net.c >> @@ -436,7 +436,8 @@ static void handle_tx(struct vhost_net *net) >> kref_get(&ubufs->kref); >> } >> nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; >> - } >> + } else > > You have to use {} on the *else* branch if you have it of the *if* > branch (and vice versa), according to Documentation/CodingStyle. checkpatch.pl didn't complain this, will send v2. Thanks > >> + msg.msg_control = NULL; > > WBR, Sergei > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html