Re: 6.0-BETA2 DRM/witness panic: Assertion j < 1000 failed at /usr/src/sys/kern/subr_witness.c:1513

From: John Baldwin <jhb_at_freebsd.org>
Date: Tue, 22 Nov 2005 14:15:26 -0500
On Tuesday 22 November 2005 08:09 am, Gavin Atkinson wrote:
> [posted to -current rather than stable as the rest of the thread started
> before 6.0 was released]
>
> On Thu, 2005-10-06 at 13:55 -0400, John Baldwin wrote:
> > On Thursday 06 October 2005 07:34 am, Gavin Atkinson wrote:
> > > On Thu, 2005-09-29 at 12:10 -0400, John Baldwin wrote:
> > > > On Tuesday 09 August 2005 12:02 pm, Gavin Atkinson wrote:
> > > > > On Tue, 2005-08-09 at 10:50 -0400, John Baldwin wrote:
> > > > > > On Tuesday 09 August 2005 07:57 am, Gavin Atkinson wrote:
> > > > > > > Hi,
> > > > > > >
> > > > > > > I have a regular panic (3 times a day) on a system running
> > > > > > > 6.0-BETA2 which was very stable under 5.4. dmesg available at
> > > > > > > http://www.devrandom.co.uk/freebsd/dmesg-buffy-20050809 . The
> > > > > > > panic seems to relate to DRM, I have a ATI Radeon QY RV100
> > > > > > > 7000/VE card.
> > > > > >
> > > > > > Do a 'show witness', it looks like witness has a cycle somehow.
> > > > > > Normally these can only occur if there is a cycle in the static
> > > > > > lock order.
> > > > >
> > > > > http://www.devrandom.co.uk/freebsd/sh-witness-buffy-20050809
> > > > >
> > > > > Gavin
> > > >
> > > > Do you still get this panic on more recent 6.0?
> > >
> > > I've been running a 6.0 from Friday for a week now without seeing this
> > > panic, so I suspect it's fixed.  However, I don't remember seeing any
> > > commits which look like they were responsible for fixing it, is it
> > > possible that it's just been masked by some other commit?  I'm happy to
> > > step back and find the responsible commit, unless you're happy that it
> > > was fixed for certain.
> > >
> > > Gavin
> >
> > Well, I'm not sure how you could even have triggered the panic in the
> > first place.  If you can't reproduce it that is fine with me for now.
>
> Sadly, it looks like I spoke too soon.  Since this last email, I was
> happily running with the kernel mentioned above without any problems,
> and an uptime of 40 days with the screensavers that used to trigger it
> running all night.  I rebooted my machine a couple of days ago, and
> since then (and with the exact same kernel/world) the panic is back.
> I've updated the machine to 6-STABLE but the panic remains.
>
> I guess I was just lucky in my month without panics - they definitely
> still exist.  I wonder if the fact that it survived so long means
> anything - e.g. is it a failure to initialise something that just by
> chance was initialised correctly that time? I'm happy to do any more
> investigating that you want.

Have you tried doing a 'show locks' when you get this panic at the db> prompt?

-- 
John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org
Received on Tue Nov 22 2005 - 18:23:30 UTC

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