Re: Panic on -CURRENT after LDT changes

2007/5/25, Joe Marcus Clarke <marcus_at_marcuscom.com>:
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> 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.
>
> I'm stopped in the debugger now with WITNESS and friends enabled.  Same
> backtrace as before.  I did a "show locks" and I see:
>
> exclusive spin mutex descriptor tables r = 0 (0xc08369f8) locked _at_
> /usr/src/sys/i386/i386/sys_machdep.c:629
>
> Please let me know what else you'd like to see while I'm at the
> debugger.  FYI: this is a Pentium 4 with "options SMP" disabled.

This is a multicore? do you have PREEMPTION/FULL_PREEMPTION installed?

Attilio


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