[    2.964432] ip (277) used greatest stack depth: 12320 bytes left
[    6.920183] ip (444) used greatest stack depth: 12272 bytes left
[  872.666872] blackhole_netdev_xmit(): Dropping skb.
[  872.666938] blackhole_netdev_xmit(): Dropping skb.
[  872.666969] blackhole_netdev_xmit(): Dropping skb.
[  872.667000] blackhole_netdev_xmit(): Dropping skb.