[    2.602619] ip (275) used greatest stack depth: 12344 bytes left
[    7.275326] ip (648) used greatest stack depth: 12296 bytes left
[   11.675413] ip (1073) used greatest stack depth: 12152 bytes left
[  732.607768] blackhole_netdev_xmit(): Dropping skb.
[  732.607936] blackhole_netdev_xmit(): Dropping skb.
[  732.607970] blackhole_netdev_xmit(): Dropping skb.
[  732.608013] blackhole_netdev_xmit(): Dropping skb.