[    2.581428] ip (277) used greatest stack depth: 12360 bytes left
[    2.631453] ip (281) used greatest stack depth: 12352 bytes left
[    2.786551] ip (291) used greatest stack depth: 12344 bytes left
[   29.420502] ip (2616) used greatest stack depth: 12296 bytes left
[  981.609252] blackhole_netdev_xmit(): Dropping skb.
[  981.609334] blackhole_netdev_xmit(): Dropping skb.
[  981.609396] blackhole_netdev_xmit(): Dropping skb.
[  981.609466] blackhole_netdev_xmit(): Dropping skb.