[    2.074637] ip (245) used greatest stack depth: 12376 bytes left
[    2.725959] ip (279) used greatest stack depth: 12360 bytes left
[    6.089402] ip (442) used greatest stack depth: 12344 bytes left
[   14.818108] ip (1188) used greatest stack depth: 12064 bytes left
[  981.430884] blackhole_netdev_xmit(): Dropping skb.
[  981.430952] blackhole_netdev_xmit(): Dropping skb.
[  981.430990] blackhole_netdev_xmit(): Dropping skb.
[  981.431035] blackhole_netdev_xmit(): Dropping skb.