[    2.714907] ip (242) used greatest stack depth: 12352 bytes left
[    3.378616] ip (280) used greatest stack depth: 12320 bytes left
[   15.465165] ip (1368) used greatest stack depth: 12304 bytes left
[  919.031705] blackhole_netdev_xmit(): Dropping skb.
[  919.031779] blackhole_netdev_xmit(): Dropping skb.
[  919.031812] blackhole_netdev_xmit(): Dropping skb.
[  919.031837] blackhole_netdev_xmit(): Dropping skb.