[  637.567205] ip (20611) used greatest stack depth: 12048 bytes left
[ 1078.468184] blackhole_netdev_xmit(): Dropping skb.
[ 1078.468252] blackhole_netdev_xmit(): Dropping skb.
[ 1078.468284] blackhole_netdev_xmit(): Dropping skb.
[ 1078.468315] blackhole_netdev_xmit(): Dropping skb.