[    2.228104] ip (273) used greatest stack depth: 12320 bytes left
[   20.426796] ip (2455) used greatest stack depth: 12304 bytes left
[  684.509851] blackhole_netdev_xmit(): Dropping skb.
[  684.509920] blackhole_netdev_xmit(): Dropping skb.
[  684.509955] blackhole_netdev_xmit(): Dropping skb.
[  684.509999] blackhole_netdev_xmit(): Dropping skb.
[  792.734321] blackhole_netdev_xmit(): Dropping skb.
[  792.734371] blackhole_netdev_xmit(): Dropping skb.
[  792.734402] blackhole_netdev_xmit(): Dropping skb.
[  792.734435] blackhole_netdev_xmit(): Dropping skb.