[    1.878450] ip (243) used greatest stack depth: 12384 bytes left
[    2.407066] ip (277) used greatest stack depth: 12352 bytes left
[  653.246939] ip (21041) used greatest stack depth: 12336 bytes left
[  946.377307] blackhole_netdev_xmit(): Dropping skb.
[  946.377368] blackhole_netdev_xmit(): Dropping skb.
[  946.377400] blackhole_netdev_xmit(): Dropping skb.
[  946.377433] blackhole_netdev_xmit(): Dropping skb.