[    2.254645] ip (276) used greatest stack depth: 12344 bytes left
[   19.012899] ip (2178) used greatest stack depth: 12328 bytes left
[  877.761290] blackhole_netdev_xmit(): Dropping skb.
[  877.761365] blackhole_netdev_xmit(): Dropping skb.
[  877.761409] blackhole_netdev_xmit(): Dropping skb.
[  877.761454] blackhole_netdev_xmit(): Dropping skb.