Help diagnosing system hangs?

[Eric Rescorla]

Nikolas Britton <nikolas.britton at gmail.com> wrote:
> On 8/23/05, Eric Rescorla <ekr at rtfm.com> wrote:
> > I've recently been experiencing frequent hangs with FreeBSD 5.3-RELEASE-p20.
> > Strangely, this didn't appear to happen with 5.3-RELEASE or before
> > a few months ago.
> > 
> > My platform is a P4-2.8 GHz (dmesg appended at end).
> > 
> > The behavior is that X freezes (sorry, I can't say if the clock is still
> > working because I forgot to check) and sshing into the box hangs.  A
> > hard reboot clears things and the box starts normally, except that it
> > fscks as expected. Nothing appears in /var/log/messages, etc.
> > 
> > Because this problem started fairly recently, my one guess is that this
> > is somehow related to the hyperthreading fix in SA-05:09. This processor
> > allegedly has hyperthreading but I'm running GENERIC. Any possibility
> > this could be responsible for hanging somehow?
> 
> Have you ruled out hardware problems, what makes you think it's
> FreeBSD? Is this problem random? etc.

(1) No, I haven't ruled out hardware problems. However, I have
    a nearly identical machine that started acting up in the
    same way in the same time frame, which is why I'm suspecting
    the OS. Meant to mention this but got bogged down in detail. Sorry!

(2) It does appear to be random, yes.

Thanks,
-Ekr