From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38810 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751474AbdCROTo (ORCPT ); Sat, 18 Mar 2017 10:19:44 -0400 Subject: Patch "mpls: Do not decrement alive counter for unregister events" has been added to the 4.10-stable tree To: dsa@cumulusnetworks.com, davem@davemloft.net, gregkh@linuxfoundation.org Cc: , From: Date: Sat, 18 Mar 2017 22:05:54 +0800 Message-ID: <148984595412989@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled mpls: Do not decrement alive counter for unregister events to the 4.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mpls-do-not-decrement-alive-counter-for-unregister-events.patch and it can be found in the queue-4.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Sat Mar 18 22:03:53 CST 2017 From: David Ahern Date: Fri, 10 Mar 2017 14:11:39 -0800 Subject: mpls: Do not decrement alive counter for unregister events From: David Ahern [ Upstream commit 79099aab38c8f5c746748b066ae74ba984fe2cc8 ] Multipath routes can be rendered usesless when a device in one of the paths is deleted. For example: $ ip -f mpls ro ls 100 nexthop as to 200 via inet 172.16.2.2 dev virt12 nexthop as to 300 via inet 172.16.3.2 dev br0 101 nexthop as to 201 via inet6 2000:2::2 dev virt12 nexthop as to 301 via inet6 2000:3::2 dev br0 $ ip li del br0 When br0 is deleted the other hop is not considered in mpls_select_multipath because of the alive check -- rt_nhn_alive is 0. rt_nhn_alive is decremented once in mpls_ifdown when the device is taken down (NETDEV_DOWN) and again when it is deleted (NETDEV_UNREGISTER). For a 2 hop route, deleting one device drops the alive count to 0. Since devices are taken down before unregistering, the decrement on NETDEV_UNREGISTER is redundant. Fixes: c89359a42e2a4 ("mpls: support for dead routes") Signed-off-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/mpls/af_mpls.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -956,7 +956,8 @@ static void mpls_ifdown(struct net_devic /* fall through */ case NETDEV_CHANGE: nh->nh_flags |= RTNH_F_LINKDOWN; - ACCESS_ONCE(rt->rt_nhn_alive) = rt->rt_nhn_alive - 1; + if (event != NETDEV_UNREGISTER) + ACCESS_ONCE(rt->rt_nhn_alive) = rt->rt_nhn_alive - 1; break; } if (event == NETDEV_UNREGISTER) Patches currently in stable-queue which might be from dsa@cumulusnetworks.com are queue-4.10/vrf-fix-use-after-free-in-vrf_xmit.patch queue-4.10/mpls-do-not-decrement-alive-counter-for-unregister-events.patch queue-4.10/mpls-send-route-delete-notifications-when-router-module-is-unloaded.patch