[    2.002060] ip (241) used greatest stack depth: 12592 bytes left
[    2.037693] ip (244) used greatest stack depth: 12352 bytes left
[    2.627838] ip (275) used greatest stack depth: 12320 bytes left
[  690.320397] blackhole_netdev_xmit(): Dropping skb.
[  690.320466] blackhole_netdev_xmit(): Dropping skb.
[  690.320499] blackhole_netdev_xmit(): Dropping skb.
[  690.320532] blackhole_netdev_xmit(): Dropping skb.