[    2.221974] ip (276) used greatest stack depth: 12320 bytes left
[   11.432526] ip (1132) used greatest stack depth: 12304 bytes left
[   12.125931] ip (1184) used greatest stack depth: 12272 bytes left
[   17.659064] ip (2150) used greatest stack depth: 12160 bytes left
[ 1014.367323] blackhole_netdev_xmit(): Dropping skb.
[ 1014.367383] blackhole_netdev_xmit(): Dropping skb.
[ 1014.367413] blackhole_netdev_xmit(): Dropping skb.
[ 1014.367441] blackhole_netdev_xmit(): Dropping skb.