The shutdown of an batman-adv interface can happen with one of its slave interfaces still being in the BATADV_IF_TO_BE_ACTIVATED state. A possible reason for it is that the routing algorithm BATMAN_V was selected and batadv_schedule_bat_ogm was not yet called for this interface. This slave interface still has to be set to BATADV_IF_INACTIVE or the batman-adv interface will never reduce its usage counter and thus never gets shutdown.

This problem can be simulated via:

$ modprobe dummy $ modprobe batman-adv routing_algo=BATMAN_V $ ip link add bat0 type batadv $ ip link set dummy0 master bat0 $ ip link set dummy0 up $ ip link del bat0 unregister_netdevice: waiting for bat0 to become free. Usage count = 3

Fixes: 88861ea9acb7 ("[batman-adv] replacing if up/down timer with kernel notifications") Reported-by: Matthias Schiffer mschiffer@universe-factory.net Signed-off-by: Sven Eckelmann sven@narfation.org --- Please check https://www.open-mesh.org/issues/248 to learn more about the bug

I have not checked why batadv_schedule_bat_ogm isn't called successfully (which would mark the interface as active) in this situation. --- net/batman-adv/hard-interface.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 3240a67..f41b472 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -572,8 +572,7 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface, struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); struct batadv_hard_iface *primary_if = NULL;

- if (hard_iface->if_status == BATADV_IF_ACTIVE) - batadv_hardif_deactivate_interface(hard_iface); + batadv_hardif_deactivate_interface(hard_iface);

if (hard_iface->if_status != BATADV_IF_INACTIVE) goto out;