[    2.274579] ip (277) used greatest stack depth: 12352 bytes left
[    5.426324] ip (455) used greatest stack depth: 12200 bytes left
[  671.907497] blackhole_netdev_xmit(): Dropping skb.
[  671.907656] blackhole_netdev_xmit(): Dropping skb.
[  671.907716] blackhole_netdev_xmit(): Dropping skb.
[  671.907778] blackhole_netdev_xmit(): Dropping skb.