From: Jiale Yao When the first port has a non-Ethernet type, team_setup_by_port() copies port_dev->type to the team device while netdev_priv() of the team device still holds a struct team. Several L2 stacks identify their devices by dev->type alone and then access type specific data that the team driver never sets up: - CAN protocols rely on the CAN mid-layer private data (ml_priv) - IEEE 802.15.4 code dereferences ieee802154_ptr and the mlme ops in ml_priv - the 6LoWPAN netdev notifier writes through lowpan_dev(dev) on NETDEV_DOWN and reads it on NETDEV_UP/NETDEV_CHANGE Enslaving such a device (e.g. vxcan, wpan0, lowpan0) therefore leads to NULL pointer dereferences or to writes into struct team. Reject ARPHRD_CAN, ARPHRD_IEEE802154, ARPHRD_IEEE802154_MONITOR and ARPHRD_6LOWPAN devices in team_port_add(). The bonding driver has rejected CAN devices since commit 8ba68464e478 ("bonding: refuse to enslave CAN devices"). Link: https://lore.kernel.org/all/b58d98e0-8fe3-4e4e-b8a5-c1c7e647ccca@hartkopp.net/ Fixes: 1d76efe1577b ("team: add support for non-ethernet devices") Assisted-by: Claude:deepseek-v4-pro Signed-off-by: Jiale Yao Signed-off-by: Oliver Hartkopp --- v4: [Hartkopp] also reject ARPHRD_6LOWPAN as reported by Sashiko AI review, reworded commit message (bonding only rejects CAN) v3: [Hartkopp] fixed indention and compilation as reported by kernel test robot --- drivers/net/team/team_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c --- a/drivers/net/team/team_core.c +++ b/drivers/net/team/team_core.c @@ -1223,10 +1223,21 @@ static int team_port_add(struct team *team, struct net_device *port_dev, netdev_err(dev, "Device %s is loopback device. Loopback devices can't be added as a team port\n", portname); return -EINVAL; } + if (port_dev->type == ARPHRD_CAN || + port_dev->type == ARPHRD_IEEE802154 || + port_dev->type == ARPHRD_IEEE802154_MONITOR || + port_dev->type == ARPHRD_6LOWPAN) { + NL_SET_ERR_MSG(extack, + "CAN, IEEE 802.15.4 and 6LoWPAN devices can't be added as a team port"); + netdev_err(dev, "Device %s is CAN, IEEE 802.15.4 or 6LoWPAN. These device types can't be added as a team port\n", + portname); + return -EINVAL; + } + if (netif_is_team_port(port_dev)) { NL_SET_ERR_MSG(extack, "Device is already a port of a team device"); netdev_err(dev, "Device %s is already a port " "of a team device\n", portname); return -EBUSY; -- 2.53.0