[    1.908785] ip (245) used greatest stack depth: 12376 bytes left
[    2.433316] ip (276) used greatest stack depth: 12344 bytes left
[    4.999956] ip (436) used greatest stack depth: 12184 bytes left
[  849.949947] blackhole_netdev_xmit(): Dropping skb.
[  849.950018] blackhole_netdev_xmit(): Dropping skb.
[  849.950057] blackhole_netdev_xmit(): Dropping skb.
[  849.950092] blackhole_netdev_xmit(): Dropping skb.