[    2.739284] ip (277) used greatest stack depth: 12336 bytes left
[  634.216688] ip (6528) used greatest stack depth: 12320 bytes left
[  798.389983] blackhole_netdev_xmit(): Dropping skb.
[  798.390056] blackhole_netdev_xmit(): Dropping skb.
[  798.390108] blackhole_netdev_xmit(): Dropping skb.
[  798.390154] blackhole_netdev_xmit(): Dropping skb.