port-amd64/48862: Asterisk goes to 100% CPU load when dnsmgr is active

[lars%gustik.eu@localhost]

>Number:         48862
>Category:       port-amd64
>Synopsis:       Asterisk goes to 100% CPU load when dnsmgr is active
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jun 01 20:15:00 +0000 2014
>Originator:     Lars Schotte
>Release:        6.1.4
>Organization:
>Environment:
NetBSD dyno 6.1.4 NetBSD 6.1.4 (GENERIC) amd64
>Description:
When I turn on dnsmgr in dnsmgr.conf to asterisk, then asterisk goes crazy and 
eats up all CPU.
The machine is not bare-metal, it is a KVM virtualized with VirtIO drivers, so 
maybe it is some timing problem, but I would not rely on that.
It is possible that this bug is reporduceable on real hardware as well.
I have several machines running Asterisk, on MIPS routers and on ARM devices, 
and dnsmgr works there well. So I suppose it may be a NetBSD specific problem.
Apart from eating up 100% CPU time, it actually works. So the issue looks to me 
something like busy waiting.
>How-To-Repeat:
When I turn on dnsmgr in dnsmgr.conf to asterisk, then asterisk goes crazy and 
eats up all CPU.
>Fix:
Never turn on dnsmgr in dnsmgr.conf to asterisk, it's the default anyway.
But when someone needs this, for example when some peers are behind dynamic 
IPv4 addresses and are not configured to register, instead they just use dyndns 
service and connection works, because port forwarding is set properly, then one 
would loose a functionality.