[ 3.5.y.z extended stable ] Patch "team: check return value of team_get_port_by_index_rcu() for" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    team: check return value of team_get_port_by_index_rcu() for

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From faff2470306e69fc07dd342ee52ca46473c295c8 Mon Sep 17 00:00:00 2001
From: Jiri Pirko <jiri at resnulli.us>
Date: Sat, 8 Jun 2013 15:00:53 +0200
Subject: [PATCH] team: check return value of team_get_port_by_index_rcu() for
 NULL

commit 76c455decbbad31de21c727edb184a963f42b40b upstream.

team_get_port_by_index_rcu() might return NULL due to race between port
removal and skb tx path. Panic is easily triggeable when txing packets
and adding/removing port in a loop.

introduced by commit 3d249d4ca "net: introduce ethernet teaming device"
and commit 753f993911b "team: introduce random mode" (for random mode)

Signed-off-by: Jiri Pirko <jiri at resnulli.us>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backported to 3.5: used davem's backport to 3.4:
  - adjusted context
  - dropped changes to team_mode_random.c ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/team/team_mode_roundrobin.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/team/team_mode_roundrobin.c b/drivers/net/team/team_mode_roundrobin.c
index 6abfbdc..d9a5e45 100644
--- a/drivers/net/team/team_mode_roundrobin.c
+++ b/drivers/net/team/team_mode_roundrobin.c
@@ -52,6 +52,8 @@ static bool rr_transmit(struct team *team, struct sk_buff *skb)

 	port_index = rr_priv(team)->sent_packets++ % team->en_port_count;
 	port = team_get_port_by_index_rcu(team, port_index);
+	if (unlikely(!port))
+		goto drop;
 	port = __get_first_port_up(team, port);
 	if (unlikely(!port))
 		goto drop;
--
1.8.1.2