Re: Panic on -CURRENT after LDT changes

From: Attilio Rao <attilio_at_freebsd.org>
Date: Thu, 24 May 2007 18:38:59 +0200
2007/5/24, Joe Marcus Clarke <marcus_at_marcuscom.com>:
> On Thu, 2007-05-24 at 18:30 +0200, Attilio Rao wrote:
> > 2007/5/24, Joe Marcus Clarke <marcus_at_marcuscom.com>:
> > > On Thu, 2007-05-24 at 20:13 +0200, Attilio Rao wrote:
> > > > Jeff Roberson wrote:
> > > > > Thanks,  Attilio and I will look at this right away.
> > > > >
> > > > > Jeff
> > > > >
> > > > > On Wed, 23 May 2007, Joe Marcus Clarke wrote:
> > > > >
> > > > >> On a -CURRENT build today with Jeff's LDT locking changes, I get an
> > > > >> instant, reproducible panic by doing:
> > > > >>
> > > > >> # cd /usr/src
> > > > >> # make -DNO_CLEAN buildworld
> > > > >>
> > > > >> Backing out the LDT changes to /sys/i386/i386/*machdep* corrects the
> > > > >> problem.  Here is a dmesg and backtrace.  In frame 6, it appears mdp is
> > > > >> NULL (i.e. td->td_proc->p_md = 0x0).
> > > >
> > > > Did you enable WITNESS/INVARIANTS/INVARIANT_SUPPORT?
> > >
> > > No, this kernel does not have WITNESS or INVARIANTS.  I can enable those
> > > tomorrow if that would give you more useful information.
> >
> > It would be very appreciated, since I've been unable to reproduce your
> > panic on a centrino dual core.
>
> Will do, but it may be that adding those options masks the bug.  Have
> you tried without them?

Yes, I tried both.
And please don't add WITNESS_SKIPSPIN since the dt_lock is a spinlock.

Thanks a lot,
Attilio


-- 
Peace can only be achieved by understanding - A. Einstein
Received on Thu May 24 2007 - 14:39:01 UTC

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