[    1.824620] ip (248) used greatest stack depth: 12376 bytes left
[    2.365316] ip (282) used greatest stack depth: 12344 bytes left
[  634.111111] ip (26491) used greatest stack depth: 12328 bytes left
[  845.949493] blackhole_netdev_xmit(): Dropping skb.
[  845.949551] blackhole_netdev_xmit(): Dropping skb.
[  845.949585] blackhole_netdev_xmit(): Dropping skb.
[  845.949615] blackhole_netdev_xmit(): Dropping skb.