[    1.990640] ip (244) used greatest stack depth: 12352 bytes left
[    2.531192] ip (275) used greatest stack depth: 12320 bytes left
[    7.554316] ip (651) used greatest stack depth: 12272 bytes left
[  976.940459] blackhole_netdev_xmit(): Dropping skb.
[  976.940518] blackhole_netdev_xmit(): Dropping skb.
[  976.940548] blackhole_netdev_xmit(): Dropping skb.
[  976.940578] blackhole_netdev_xmit(): Dropping skb.
[ 1186.241218] blackhole_netdev_xmit(): Dropping skb.
[ 1186.241268] blackhole_netdev_xmit(): Dropping skb.
[ 1186.241298] blackhole_netdev_xmit(): Dropping skb.
[ 1186.241324] blackhole_netdev_xmit(): Dropping skb.