[    2.422144] ip (275) used greatest stack depth: 12320 bytes left
[    7.751191] ip (651) used greatest stack depth: 12016 bytes left
[  679.123617] blackhole_netdev_xmit(): Dropping skb.
[  679.123705] blackhole_netdev_xmit(): Dropping skb.
[  679.123742] blackhole_netdev_xmit(): Dropping skb.
[  679.123781] blackhole_netdev_xmit(): Dropping skb.