[    1.730025] ip (244) used greatest stack depth: 12352 bytes left
[    1.757286] ip (247) used greatest stack depth: 12304 bytes left
[   19.767817] ip (2365) used greatest stack depth: 12272 bytes left
[  626.637943] ip (10179) used greatest stack depth: 12128 bytes left
[ 1044.058058] blackhole_netdev_xmit(): Dropping skb.
[ 1044.058134] blackhole_netdev_xmit(): Dropping skb.
[ 1044.058171] blackhole_netdev_xmit(): Dropping skb.
[ 1044.058221] blackhole_netdev_xmit(): Dropping skb.