[    2.900972] ip (278) used greatest stack depth: 12352 bytes left
[  656.384097] ip (23418) used greatest stack depth: 12200 bytes left
[  968.568553] blackhole_netdev_xmit(): Dropping skb.
[  968.568637] blackhole_netdev_xmit(): Dropping skb.
[  968.568676] blackhole_netdev_xmit(): Dropping skb.
[  968.568710] blackhole_netdev_xmit(): Dropping skb.