>From code inspection it appeared that there is a possibility where in ipvlan_port_destroy() might be dealing with a port (struct ipvl_port) that has already been destroyed and is therefore already NULL. However, we don't check for NULL and continue to access the fields which results in a kernel panic.
When call to register_netdevice() (called from ipvlan_link_new()) fails, inside that function we call ipvlan_uninit() (through ndo_uninit()) to destroy the ipvlan port. Upon returning unsuccessfully from register_netdevice() we go ahead and call ipvlan_port_destroy() again which causes NULL pointer dereference panic. To test this theory, I loaded up netdev-notifier-error-inject.ko and did $ sudo echo -22 > /sys/kernel/debug/notifier-error-inject/\ netdev/actions/NETDEV_POST_INIT/error $ sudo ip li add ipvl0 link enp7s0 type ipvlan ...system panics... BUG: unable to handle kernel NULL pointer dereference at 0000000000000820 IP: ipvlan_port_destroy+0x2a/0xf0 [ipvlan] Similar issue exists in macvlan_port_destroy() and it will be addressed by a separate patch. The following patch fixes the ipvlan case. I tested my changes for regression by running LTP's ipvlan test case. Girish Moodalbail (1): ipvlan: NULL pointer dereference panic in ipvlan_port_destroy drivers/net/ipvlan/ipvlan_main.c | 104 +++++++++++++++++++++------------------ 1 file changed, 55 insertions(+), 49 deletions(-) -- 1.8.3.1
