[    1.778019] ip (246) used greatest stack depth: 12304 bytes left
[   19.170290] ip (2507) used greatest stack depth: 12256 bytes left
[ 1159.831051] blackhole_netdev_xmit(): Dropping skb.
[ 1159.831214] blackhole_netdev_xmit(): Dropping skb.
[ 1159.831266] blackhole_netdev_xmit(): Dropping skb.
[ 1159.831318] blackhole_netdev_xmit(): Dropping skb.