[    2.530232] ip (275) used greatest stack depth: 12344 bytes left
[    4.940693] ip (436) used greatest stack depth: 12296 bytes left
[    5.129277] ip (450) used greatest stack depth: 12184 bytes left
[ 1178.298962] blackhole_netdev_xmit(): Dropping skb.
[ 1178.299053] blackhole_netdev_xmit(): Dropping skb.
[ 1178.299099] blackhole_netdev_xmit(): Dropping skb.
[ 1178.299147] blackhole_netdev_xmit(): Dropping skb.