[    2.705466] ip (276) used greatest stack depth: 12336 bytes left
[    2.928779] ip (290) used greatest stack depth: 12064 bytes left
[  726.784538] hrtimer: interrupt took 3154508 ns
[  738.219892] blackhole_netdev_xmit(): Dropping skb.
[  738.219952] blackhole_netdev_xmit(): Dropping skb.
[  738.219987] blackhole_netdev_xmit(): Dropping skb.
[  738.220023] blackhole_netdev_xmit(): Dropping skb.