From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752723Ab3FYSeR (ORCPT ); Tue, 25 Jun 2013 14:34:17 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:41084 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752675Ab3FYSeN (ORCPT ); Tue, 25 Jun 2013 14:34:13 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Wang , "Michael S. Tsirkin" , "David S. Miller" Subject: [ 66/95] vhost_net: clear msg.control for non-zerocopy case during tx Date: Tue, 25 Jun 2013 11:32:53 -0700 Message-Id: <20130625182201.051651141@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130625182153.605455184@linuxfoundation.org> References: <20130625182153.605455184@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang [ Upstream commit 4364d5f96eed7994a2c625bd9216656e55fba0cb ] 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 Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -353,7 +353,8 @@ static void handle_tx(struct vhost_net * kref_get(&ubufs->kref); } vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV; - } + } else + msg.msg_control = NULL; /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(NULL, sock, &msg, len); if (unlikely(err < 0)) {