Netgraph initialization race?

[Anton Ivanov]

Hi list,

I think I found a race condition somewhere in the netgraph subsystem

It can be reproduced around 80% of the time on any 4.8 through 4.9-RC to
5.1-RELENG, possibly earlier. 4.7 IFIRC did not have the problem.

If you start two mpd processes immediately one after another listening
on different IPs with different interface ranges (ng1-ng32) and
(ng33-ng64) you get a hang. Currently running processes continue to run.
New processes cannot be created. mpd instances cannot be killed. 

I have also noticed that if you start and stop an mpd now you get a ng0
interface left after mpd exits. 

Brgds,
A.