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>

1 files changed, 26 insertions, 23 deletions

diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c
index 20f731f08c7e..bf09d79afd4d 100644
--- 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);
                 }
         }