[    2.379284] ip (276) used greatest stack depth: 12320 bytes left
[    4.647499] ip (406) used greatest stack depth: 12304 bytes left
[    9.441922] ip (945) used greatest stack depth: 12272 bytes left
[  799.410605] blackhole_netdev_xmit(): Dropping skb.
[  799.410663] blackhole_netdev_xmit(): Dropping skb.
[  799.410697] blackhole_netdev_xmit(): Dropping skb.
[  799.410725] blackhole_netdev_xmit(): Dropping skb.