Hello Petr Machata,
The patch ec4643ca3d98: "mlxsw: spectrum_switchdev: Replay switchdev
objects on port join" from Jul 19, 2023 (linux-next), leads to the
following Smatch static checker warning:
drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c:2679 mlxsw_sp_bridge_8021d_port_join()
error: we previously assumed 'mlxsw_sp_port_vlan->fid' could be null (see line 2664)
drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
2642 static int
2643 mlxsw_sp_bridge_8021d_port_join(struct mlxsw_sp_bridge_device *bridge_device,
2644 struct mlxsw_sp_bridge_port *bridge_port,
2645 struct mlxsw_sp_port *mlxsw_sp_port,
2646 struct netlink_ext_ack *extack)
2647 {
2648 struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan;
2649 struct net_device *dev = bridge_port->dev;
2650 u16 vid;
2651 int err;
2652
2653 vid = is_vlan_dev(dev) ? vlan_dev_vlan_id(dev) : MLXSW_SP_DEFAULT_VID;
2654 mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_find_by_vid(mlxsw_sp_port, vid);
2655 if (WARN_ON(!mlxsw_sp_port_vlan))
2656 return -EINVAL;
2657
2658 if (mlxsw_sp_port_is_br_member(mlxsw_sp_port, bridge_device->dev)) {
2659 NL_SET_ERR_MSG_MOD(extack, "Can not bridge VLAN uppers of the same port");
2660 return -EINVAL;
2661 }
2662
2663 /* Port is no longer usable as a router interface */
2664 if (mlxsw_sp_port_vlan->fid)
This has a check for NULL.
2665 mlxsw_sp_port_vlan_router_leave(mlxsw_sp_port_vlan);
2666
2667 err = mlxsw_sp_port_vlan_bridge_join(mlxsw_sp_port_vlan, bridge_port,
2668 extack);
Most of the time this would set ->fid but if mlxsw_sp_port_vlan->bridge_port
then it wouldn't
2669 if (err)
2670 return err;
2671
2672 err = mlxsw_sp_bridge_port_replay(bridge_port, mlxsw_sp_port, extack);
2673 if (err)
2674 goto err_replay;
2675
2676 return 0;
2677
2678 err_replay:
--> 2679 mlxsw_sp_port_vlan_bridge_leave(mlxsw_sp_port_vlan);
->fid dereferenced without being checked.
2680 return err;
2681 }
regards,
dan carpenter
