[    2.157225] ip (244) used greatest stack depth: 12560 bytes left
[    2.796588] ip (275) used greatest stack depth: 12336 bytes left
[    6.789015] ip (460) used greatest stack depth: 12224 bytes left
[  861.555923] blackhole_netdev_xmit(): Dropping skb.
[  861.555990] blackhole_netdev_xmit(): Dropping skb.
[  861.556023] blackhole_netdev_xmit(): Dropping skb.
[  861.556054] blackhole_netdev_xmit(): Dropping skb.
[  953.981336] ip (15362) used greatest stack depth: 12176 bytes left
[ 1087.334898] blackhole_netdev_xmit(): Dropping skb.
[ 1087.334958] blackhole_netdev_xmit(): Dropping skb.
[ 1087.334993] blackhole_netdev_xmit(): Dropping skb.
[ 1087.335039] blackhole_netdev_xmit(): Dropping skb.