ipfw uid rules cause lockup (was Re: PREEMPTION still unusable with 6.0-RC1)

On Sat, 2005-10-22 at 19:45 +0400, Gleb Smirnoff wrote:
> On Fri, Oct 21, 2005 at 09:17:29AM +0200, Stefan Ehmann wrote:
> S> I recently upgraded my 5.4-RELEASE machine to 6.0-RC1. Runs fine so far
> S> if I disable PREEMPTION.
> S> 
> S> With PREEMPTION enabled, I still get the same issues as described here:
> S> http://lists.freebsd.org/pipermail/freebsd-current/2004-September/037949.html
> S> 
> S> kernel config:
> S> http://stud4.tuwien.ac.at/~e0125637/fbsd/kernconf-6.0-RC1
> S> 
> S> /var/log/messages output:
> S> http://stud4.tuwien.ac.at/~e0125637/fbsd/messages-6.0-RC1
> S> 
> S> Any one else still experiencing these problems or has any idea what
> S> causes this?
> S> 
> S> BTW, are 6.0 discussions supposed to go to stable_at_ once 6.0 is released?
> 
> AFAIK, the uid/gid rules in ipfw(8) require debug.mpsafenet=0. So
> your deadlock isn't a surprise. I wonder why this limitation isn't
> documented.

A quick google search revealed
http://www.freebsd.org/releases/5.3R/errata.html

(31 Oct 2004) When the user/group rule clauses in pf(4) and ipfw(4) are
used, the loader tunable debug.mpsafenet must be set to 0 (this is 1 by
default).

But this is supposed to be fixed in 5.4 (OTOH 5.4 doesn't have
PREEMPTION enabled by default). I'll try tomorrow if debug.mpsafenet=0
will help.