Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754015Ab3F1S6O (ORCPT ); Fri, 28 Jun 2013 14:58:14 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:41956 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753983Ab3F1S6L (ORCPT ); Fri, 28 Jun 2013 14:58:11 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jason Wang , "David S. Miller" , Kamal Mostafa Subject: [PATCH 082/105] vhost_net: clear msg.control for non-zerocopy case during tx Date: Fri, 28 Jun 2013 11:51:44 -0700 Message-Id: <1372445527-24414-83-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1372445527-24414-1-git-send-email-kamal@canonical.com> References: <1372445527-24414-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2778 Lines: 68 3.8.13.4 -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: Kamal Mostafa --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index ec6fb3f..dfff647 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -353,7 +353,8 @@ static void handle_tx(struct vhost_net *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)) { -- 1.8.1.2 -- 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/