[    2.487777] ip (276) used greatest stack depth: 12320 bytes left
[  627.558967] ip (21386) used greatest stack depth: 12304 bytes left
[  805.325405] blackhole_netdev_xmit(): Dropping skb.
[  805.325484] blackhole_netdev_xmit(): Dropping skb.
[  805.325533] blackhole_netdev_xmit(): Dropping skb.
[  805.325582] blackhole_netdev_xmit(): Dropping skb.
[  951.861359] ip (25876) used greatest stack depth: 12272 bytes left