4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Fainelli <f.fainelli@xxxxxxxxx> [ Upstream not applicable ] It is possible for the DSA slave network device not to be part of a bridge, yet have an upper device like a VLAN device be part of a bridge. When that VLAN device is enslaved, since it does not define any switchdev_ops, we will recurse down to the lower/physical port device, call switchdev_port_obj_add() with a VLAN, and here we will check br_vlan_enabled() on a NULL dp->bridge_dev, thus causing a NULL pointer de-reference. This is no longer a problem upstream after commit d17d9f5e5143 ("switchdev: Replace port obj add/del SDO with a notification"). Fixes: 2ea7a679ca2a ("net: dsa: Don't add vlans when vlan filtering is disabled") Reported-by: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/dsa/port.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/dsa/port.c +++ b/net/dsa/port.c @@ -255,7 +255,7 @@ int dsa_port_vlan_add(struct dsa_port *d if (netif_is_bridge_master(vlan->obj.orig_dev)) return -EOPNOTSUPP; - if (br_vlan_enabled(dp->bridge_dev)) + if (dp->bridge_dev && br_vlan_enabled(dp->bridge_dev)) return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_ADD, &info); return 0; @@ -273,7 +273,7 @@ int dsa_port_vlan_del(struct dsa_port *d if (netif_is_bridge_master(vlan->obj.orig_dev)) return -EOPNOTSUPP; - if (br_vlan_enabled(dp->bridge_dev)) + if (dp->bridge_dev && br_vlan_enabled(dp->bridge_dev)) return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_DEL, &info); return 0;