[    2.406658] ip (276) used greatest stack depth: 12344 bytes left
[   20.306862] ip (2215) used greatest stack depth: 12072 bytes left
[  974.556427] blackhole_netdev_xmit(): Dropping skb.
[  974.556496] blackhole_netdev_xmit(): Dropping skb.
[  974.556527] blackhole_netdev_xmit(): Dropping skb.
[  974.556560] blackhole_netdev_xmit(): Dropping skb.