[    2.519597] ip (275) used greatest stack depth: 12336 bytes left
[  642.396792] ip (4771) used greatest stack depth: 12320 bytes left
[  647.279672] ip (5099) used greatest stack depth: 12048 bytes left
[  723.362195] blackhole_netdev_xmit(): Dropping skb.
[  723.362255] blackhole_netdev_xmit(): Dropping skb.
[  723.362295] blackhole_netdev_xmit(): Dropping skb.
[  723.362332] blackhole_netdev_xmit(): Dropping skb.
[ 1029.748962] blackhole_netdev_xmit(): Dropping skb.
[ 1029.749024] blackhole_netdev_xmit(): Dropping skb.
[ 1029.749059] blackhole_netdev_xmit(): Dropping skb.
[ 1029.749105] blackhole_netdev_xmit(): Dropping skb.