[26/88] team: check return value of team_get_port_by_index_rcu() for NULL

Steven Rostedt
2013-08-13T15:58:38Z

[-- Attachment #1: 0026-team-check-return-value-of-team_get_port_by_index_rc.patch --]
[-- Type: text/plain, Size: 1322 bytes --]

3.6.11.7-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Jiri Pirko <jiri@resnulli.us>

[ Upstream commit 76c455decbbad31de21c727edb184a963f42b40b ]

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@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
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 ad7ed0e..dcbe6ba 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;
--
1.7.10.4