[    1.647630] ip (245) used greatest stack depth: 12352 bytes left
[    2.045511] ip (276) used greatest stack depth: 12320 bytes left
[    4.818393] ip (440) used greatest stack depth: 12160 bytes left
[  899.318647] blackhole_netdev_xmit(): Dropping skb.
[  899.318803] blackhole_netdev_xmit(): Dropping skb.
[  899.318842] blackhole_netdev_xmit(): Dropping skb.
[  899.318881] blackhole_netdev_xmit(): Dropping skb.