[    1.970668] ip (243) used greatest stack depth: 12376 bytes left
[    2.680685] ip (274) used greatest stack depth: 12352 bytes left
[   14.311783] ip (1174) used greatest stack depth: 12344 bytes left
[  716.615509] blackhole_netdev_xmit(): Dropping skb.
[  716.615573] blackhole_netdev_xmit(): Dropping skb.
[  716.615606] blackhole_netdev_xmit(): Dropping skb.
[  716.615639] blackhole_netdev_xmit(): Dropping skb.