[PATCH 3.18 12/86] team: fix possible recursive locking when add slaves

From: Greg Kroah-Hartman
Date: Wed May 15 2019 - 06:59:55 EST

From: Hangbin Liu <liuhangbin@xxxxxxxxx>

[ Upstream commit 925b0c841e066b488cc3a60272472b2c56300704 ]

If we add a bond device which is already the master of the team interface,
we will hold the team->lock in team_add_slave() first and then request the
lock in team_set_mac_address() again. The functions are called like:

- team_add_slave()
- team_port_add()
- team_port_enter()
- team_modeop_port_enter()
- __set_port_dev_addr()
- dev_set_mac_address()
- bond_set_mac_address()
- dev_set_mac_address()
- team_set_mac_address

Although team_upper_dev_link() would check the upper devices but it is
called too late. Fix it by adding a checking before processing the slave.

v2: Do not split the string in netdev_err()

Fixes: 3d249d4ca7d0 ("net: introduce ethernet teaming device")
Acked-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/net/team/team.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -1137,6 +1137,12 @@ static int team_port_add(struct team *te
return -EINVAL;

+ if (netdev_has_upper_dev(dev, port_dev)) {
+ netdev_err(dev, "Device %s is already an upper device of the team interface\n",
+ portname);
+ return -EBUSY;
+ }
if (port_dev->features & NETIF_F_VLAN_CHALLENGED &&
vlan_uses_dev(dev)) {
netdev_err(dev, "Device %s is VLAN challenged and team device has VLAN set up\n",