IB/mlx4: Avoid null pointer dereference in mlx4_ib_scan_netdevs()

When Ethernet netdev is not present for a port (e.g. when the link
layer type of the port is InfiniBand) it's possible to dereference a
null pointer when we do netdevice scanning.

To fix that, we move a section of code that needs to run only when
netdev is present to a proper if () statement.

Fixes: ad4885d279b6 ("IB/mlx4: Build the port IBoE GID table properly under bonding")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c
index 20f731f08c7ed3c2751de3cd9920a6cbb1a925c0..bf09d79afd4dade38e2753b30902eacdc6bd7216 100644 (file)
--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -1789,31 +1789,34 @@ static void mlx4_ib_scan_netdevs(struct mlx4_ib_dev *ibdev,
                        port_state = (netif_running(curr_netdev) && netif_carrier_ok(curr_netdev)) ?
                                                IB_PORT_ACTIVE : IB_PORT_DOWN;
                        mlx4_ib_set_default_gid(ibdev, curr_netdev, port);
-               } else {
-                       reset_gid_table(ibdev, port);
-               }
-               /* if using bonding/team and a slave port is down, we don't the bond IP
-                * based gids in the table since flows that select port by gid may get
-                * the down port.
-                */
-               if (curr_master && (port_state == IB_PORT_DOWN)) {
-                       reset_gid_table(ibdev, port);
-                       mlx4_ib_set_default_gid(ibdev, curr_netdev, port);
-               }
-               /* if bonding is used it is possible that we add it to masters
-                * only after IP address is assigned to the net bonding
-                * interface.
-               */
-               if (curr_master && (old_master != curr_master)) {
-                       reset_gid_table(ibdev, port);
-                       mlx4_ib_set_default_gid(ibdev, curr_netdev, port);
-                       mlx4_ib_get_dev_addr(curr_master, ibdev, port);
-               }
+                       /* if using bonding/team and a slave port is down, we
+                        * don't the bond IP based gids in the table since
+                        * flows that select port by gid may get the down port.
+                        */
+                       if (curr_master && (port_state == IB_PORT_DOWN)) {
+                               reset_gid_table(ibdev, port);
+                               mlx4_ib_set_default_gid(ibdev,
+                                                       curr_netdev, port);
+                       }
+                       /* if bonding is used it is possible that we add it to
+                        * masters only after IP address is assigned to the
+                        * net bonding interface.
+                       */
+                       if (curr_master && (old_master != curr_master)) {
+                               reset_gid_table(ibdev, port);
+                               mlx4_ib_set_default_gid(ibdev,
+                                                       curr_netdev, port);
+                               mlx4_ib_get_dev_addr(curr_master, ibdev, port);
+                       }
 
-               if (!curr_master && (old_master != curr_master)) {
+                       if (!curr_master && (old_master != curr_master)) {
+                               reset_gid_table(ibdev, port);
+                               mlx4_ib_set_default_gid(ibdev,
+                                                       curr_netdev, port);
+                               mlx4_ib_get_dev_addr(curr_netdev, ibdev, port);
+                       }
+               } else {
                        reset_gid_table(ibdev, port);
-                       mlx4_ib_set_default_gid(ibdev, curr_netdev, port);
-                       mlx4_ib_get_dev_addr(curr_netdev, ibdev, port);
                }
        }