[    1.964122] ip (242) used greatest stack depth: 12384 bytes left
[    2.570653] ip (276) used greatest stack depth: 12352 bytes left
[   11.918293] ip (1076) used greatest stack depth: 12312 bytes left
[  729.207057] blackhole_netdev_xmit(): Dropping skb.
[  729.207137] blackhole_netdev_xmit(): Dropping skb.
[  729.207191] blackhole_netdev_xmit(): Dropping skb.
[  729.207253] blackhole_netdev_xmit(): Dropping skb.