[    2.194245] ip (249) used greatest stack depth: 12376 bytes left
[    2.828259] ip (277) used greatest stack depth: 12352 bytes left
[    8.731249] ip (648) used greatest stack depth: 12344 bytes left
[  818.096030] blackhole_netdev_xmit(): Dropping skb.
[  818.096105] blackhole_netdev_xmit(): Dropping skb.
[  818.096138] blackhole_netdev_xmit(): Dropping skb.
[  818.096175] blackhole_netdev_xmit(): Dropping skb.