[    2.337335] ip (275) used greatest stack depth: 12320 bytes left
[    4.698163] ip (406) used greatest stack depth: 12304 bytes left
[   13.371644] ip (1410) used greatest stack depth: 12048 bytes left
[  656.849710] blackhole_netdev_xmit(): Dropping skb.
[  656.849773] blackhole_netdev_xmit(): Dropping skb.
[  656.849804] blackhole_netdev_xmit(): Dropping skb.
[  656.849837] blackhole_netdev_xmit(): Dropping skb.