[    2.310318] ip (272) used greatest stack depth: 12344 bytes left
[   23.015169] ip (2501) used greatest stack depth: 12184 bytes left
[  642.953299] ip (8101) used greatest stack depth: 12056 bytes left
[  689.225642] blackhole_netdev_xmit(): Dropping skb.
[  689.225714] blackhole_netdev_xmit(): Dropping skb.
[  689.225754] blackhole_netdev_xmit(): Dropping skb.
[  689.225794] blackhole_netdev_xmit(): Dropping skb.