[    2.094741] ip (274) used greatest stack depth: 12320 bytes left
[  628.869316] ip (2770) used greatest stack depth: 12048 bytes left
[  879.152853] blackhole_netdev_xmit(): Dropping skb.
[  879.152929] blackhole_netdev_xmit(): Dropping skb.
[  879.152973] blackhole_netdev_xmit(): Dropping skb.
[  879.153017] blackhole_netdev_xmit(): Dropping skb.