[    1.992766] ip (275) used greatest stack depth: 12320 bytes left
[   16.977385] ip (2215) used greatest stack depth: 12272 bytes left
[  984.467001] blackhole_netdev_xmit(): Dropping skb.
[  984.467065] blackhole_netdev_xmit(): Dropping skb.
[  984.467104] blackhole_netdev_xmit(): Dropping skb.
[  984.467143] blackhole_netdev_xmit(): Dropping skb.