[    2.576870] ip (278) used greatest stack depth: 12352 bytes left
[    7.804003] ip (653) used greatest stack depth: 12312 bytes left
[  999.833075] blackhole_netdev_xmit(): Dropping skb.
[  999.833139] blackhole_netdev_xmit(): Dropping skb.
[  999.833184] blackhole_netdev_xmit(): Dropping skb.
[  999.833211] blackhole_netdev_xmit(): Dropping skb.