[    1.923023] ip (243) used greatest stack depth: 12352 bytes left
[    2.545087] ip (274) used greatest stack depth: 12320 bytes left
[   10.565252] ip (945) used greatest stack depth: 12144 bytes left
[ 1175.561196] blackhole_netdev_xmit(): Dropping skb.
[ 1175.561262] blackhole_netdev_xmit(): Dropping skb.
[ 1175.561292] blackhole_netdev_xmit(): Dropping skb.
[ 1175.561326] blackhole_netdev_xmit(): Dropping skb.