[    2.054493] ip (241) used greatest stack depth: 12376 bytes left
[    2.617216] ip (275) used greatest stack depth: 12344 bytes left
[    2.862392] hrtimer: interrupt took 3892925 ns
[   12.375452] ip (1073) used greatest stack depth: 12184 bytes left
[  704.869592] blackhole_netdev_xmit(): Dropping skb.
[  704.869663] blackhole_netdev_xmit(): Dropping skb.
[  704.869701] blackhole_netdev_xmit(): Dropping skb.
[  704.869742] blackhole_netdev_xmit(): Dropping skb.