[    2.041676] ip (275) used greatest stack depth: 12320 bytes left
[    4.762911] ip (438) used greatest stack depth: 12272 bytes left
[  629.547405] ip (4038) used greatest stack depth: 12216 bytes left
[  634.635734] ip (4858) used greatest stack depth: 12176 bytes left
[ 1013.054503] blackhole_netdev_xmit(): Dropping skb.
[ 1013.054572] blackhole_netdev_xmit(): Dropping skb.
[ 1013.054607] blackhole_netdev_xmit(): Dropping skb.
[ 1013.054642] blackhole_netdev_xmit(): Dropping skb.