[    1.940310] ip (245) used greatest stack depth: 12376 bytes left
[    2.470081] ip (276) used greatest stack depth: 12360 bytes left
[    5.869873] ip (439) used greatest stack depth: 12344 bytes left
[  634.261785] ip (23219) used greatest stack depth: 12328 bytes left
[ 1102.923374] blackhole_netdev_xmit(): Dropping skb.
[ 1102.923448] blackhole_netdev_xmit(): Dropping skb.
[ 1102.923484] blackhole_netdev_xmit(): Dropping skb.
[ 1102.923519] blackhole_netdev_xmit(): Dropping skb.