Patchwork [20/50] team: check return value of team_get_port_by_index_rcu() for NULL

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Submitter Luis Henriques
Date July 2, 2013, 11:07 a.m.
Message ID <1372763258-20664-21-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/256357/
State New
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Luis Henriques - July 2, 2013, 11:07 a.m.
3.5.7.16 -stable review patch.  If anyone has any objections, please let me know.

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

From: Jiri Pirko <jiri@resnulli.us>

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@resnulli.us>
Signed-off-by: David S. Miller <davem@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@canonical.com>
---
 drivers/net/team/team_mode_roundrobin.c | 2 ++
 1 file changed, 2 insertions(+)

Patch

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;