[    1.801656] ip (246) used greatest stack depth: 12376 bytes left
[    2.340736] ip (277) used greatest stack depth: 12360 bytes left
[    2.554728] ip (291) used greatest stack depth: 12344 bytes left
[  963.042037] blackhole_netdev_xmit(): Dropping skb.
[  963.042098] blackhole_netdev_xmit(): Dropping skb.
[  963.042129] blackhole_netdev_xmit(): Dropping skb.
[  963.042156] blackhole_netdev_xmit(): Dropping skb.