[    2.141173] ip (276) used greatest stack depth: 12320 bytes left
[  629.319789] ip (9367) used greatest stack depth: 12304 bytes left
[  646.077806] blackhole_netdev_xmit(): Dropping skb.
[  646.077873] blackhole_netdev_xmit(): Dropping skb.
[  646.077914] blackhole_netdev_xmit(): Dropping skb.
[  646.077953] blackhole_netdev_xmit(): Dropping skb.
[  971.209891] blackhole_netdev_xmit(): Dropping skb.
[  971.209975] blackhole_netdev_xmit(): Dropping skb.
[  971.210015] blackhole_netdev_xmit(): Dropping skb.
[  971.210054] blackhole_netdev_xmit(): Dropping skb.