[    1.818888] ip (241) used greatest stack depth: 12832 bytes left
[    1.845851] ip (244) used greatest stack depth: 12352 bytes left
[    2.281226] ip (275) used greatest stack depth: 12320 bytes left
[    7.945975] ip (785) used greatest stack depth: 12160 bytes left
[  731.873019] blackhole_netdev_xmit(): Dropping skb.
[  731.873089] blackhole_netdev_xmit(): Dropping skb.
[  731.873128] blackhole_netdev_xmit(): Dropping skb.
[  731.873171] blackhole_netdev_xmit(): Dropping skb.