[    2.301650] ip (273) used greatest stack depth: 12336 bytes left
[    4.115174] ip (410) used greatest stack depth: 12320 bytes left
[  651.883264] blackhole_netdev_xmit(): Dropping skb.
[  651.883338] blackhole_netdev_xmit(): Dropping skb.
[  651.883387] blackhole_netdev_xmit(): Dropping skb.
[  651.883423] blackhole_netdev_xmit(): Dropping skb.