How to report bugs (Re: 6.2-STABLE deadlock?)

[Kris Kennaway]

On Wed, Apr 25, 2007 at 10:53:08AM +0800, LI Xin wrote:
> Hi, Oleg,
> 
> Oleg Derevenetz wrote:
> > ??????? LI Xin <delphij at delphij.net>:
> [...]
> >> I'm not very sure if this is specific to one disk controller.  Actually
> >> I got some occasional reports about similar hangs on amd64 6.2-RELEASE
> >> (slightly patched version) that most of processes stuck in the 'ufs'
> >> state, under very light load, the box was equipped with amr(4) RAID.
> >>
> >> I was not able to reproduce the problem at my lab, though, it's still
> >> unknown that how to trigger the livelock :-(  Still need some
> >> investigate on their production system.
> > 
> > I reported simular issue for FreeBSD 6.2 in audit-trail for kern/104406:
> > 
> > http://www.freebsd.org/cgi/query-pr.cgi?pr=104406&cat=
> > 
> > and there should be a thread related to this. Briefly, I suspects that this is 
> > related to nullfs filesystems on my server and when I cvsuped to FreeBSD 6.2-
> > STABLE with Daichi's unionfs-related patches and replaced nullfs-mounted fs 
> > with unionfs-mounted (that was done 10.03.07) problem is gone (seems to be so, 
> > at least).
> 
> Hmm...  Seems to be different issues.  The problem I have received was a
> pgsql server (no nullfs/unionfs involved), and the hang always happen
> when it is not being heavily loaded (usually in the morning, for
> instance, and there is no special configuration, like scheduled tasks
> which can generate disk load, etc., only the entropy harvesting), so
> this is quite confusing.

Yes, a large part of the confusion is the unfortunate tendency of
people to do the following:

<user1> my system hangs/panics/etc
<user2> my system hangs/panics/etc too; it must be the same problem!

What we really need is for every FreeBSD user who encounters a
hang/panic/etc to avoid jumping to conclusions -- no matter how many
superficial similarities there may seem to you -- and instead go
through the relevant steps described here:

  http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html

Until you (or a developer) have analyzed the resulting information,
you cannot definitively determine whether or not your problem is the
same as a given random other problem, and you may just confuse the
issue by making claims of similarity when you are really reporting a
completely separate problem.

Thanks,
Kris
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