[    2.154033] ip (275) used greatest stack depth: 12320 bytes left
[    6.436098] ip (613) used greatest stack depth: 12304 bytes left
[  637.839247] ip (14432) used greatest stack depth: 12272 bytes left
[  928.950335] blackhole_netdev_xmit(): Dropping skb.
[  928.950410] blackhole_netdev_xmit(): Dropping skb.
[  928.950459] blackhole_netdev_xmit(): Dropping skb.
[  928.950510] blackhole_netdev_xmit(): Dropping skb.