[    1.690773] ip (241) used greatest stack depth: 12352 bytes left
[    2.109341] ip (275) used greatest stack depth: 12320 bytes left
[    2.248480] ip (289) used greatest stack depth: 12224 bytes left
[  812.601418] blackhole_netdev_xmit(): Dropping skb.
[  812.601490] blackhole_netdev_xmit(): Dropping skb.
[  812.601531] blackhole_netdev_xmit(): Dropping skb.
[  812.601569] blackhole_netdev_xmit(): Dropping skb.