Re: panic: APIC: Previous IPI is stuck

From: Brian Fundakowski Feldman <green_at_FreeBSD.org>
Date: Tue, 28 Sep 2004 11:56:25 -0400
On Tue, Sep 28, 2004 at 11:42:09AM -0400, John Baldwin wrote:
> On Monday 27 September 2004 05:55 pm, Brian Fundakowski Feldman wrote:
> > On Mon, Sep 27, 2004 at 04:35:44PM -0400, John Baldwin wrote:
> > > On Friday 24 September 2004 08:24 pm, Andy Farkas wrote:
> > > > I have been having this problem for a few weeks now. Glad I'm not the
> > > > only one. My box is a 4xPPro running 5.3-BETA5. It panics with either
> > > > ULE or 4BSD.
> > > >
> > > > My theory is that a physical IPI gets lost somewhere and the kerenl
> > > > spins waiting for it. But thats just a stab in the dark because nobody
> > > > cares to explain why IPI's would be stuck.
> > >
> > > The panic has to do with a previous IPI not finished being sent from the
> > > same CPU.  I've yet to determine why this happens.  You can try editing
> > > sys/i386/i386/local_apic.c and turning on 'DETECT_DEADLOCK' (I think it
> > > is just commented out) and seeing if that improves stability.  I also see
> > > this on a 4xPIIXeon system I use for testing.
> >
> > Can KTR logging be leveraged to find the root cause(s) of these deadlocks,
> > or is it just so wildly unpredictable that it would be of no use?
> 
> It might could be, but I think it would probably slow things down so much that 
> they would go away.

Well, we have had users with machines that would get an IPI deadlock within
only a few hours, so it might be worth trying with those users....

-- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green_at_FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\
Received on Tue Sep 28 2004 - 13:56:32 UTC

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