[    1.825748] ip (241) used greatest stack depth: 12832 bytes left
[    1.858759] ip (244) used greatest stack depth: 12376 bytes left
[    2.388924] ip (275) used greatest stack depth: 12344 bytes left
[  637.333944] ip (22781) used greatest stack depth: 12072 bytes left
[ 1079.483576] blackhole_netdev_xmit(): Dropping skb.
[ 1079.483643] blackhole_netdev_xmit(): Dropping skb.
[ 1079.483677] blackhole_netdev_xmit(): Dropping skb.
[ 1079.483710] blackhole_netdev_xmit(): Dropping skb.