panic upon kldunload snd_ich (lor # 159)

[Ben Kaduk]

On 9/12/05, Alexander Leidinger <Alexander at leidinger.net> wrote:
> 
> On Mon, 12 Sep 2005 04:04:48 +0000
> Ben Kaduk <minimarmot at gmail.com> wrote:
> 
> > Booting to single user and issuing:
> > # kldload snd_ich
> > # kldunload snd_ich
> >
> > are sufficient to trigger the panic on my system. I know that Alexander
> > Leidinger has recently committed some bits to current in the sound code, 
> but
> > it is unclear if it will fix my panic; I'm currently cvsup-ing and 
> building
> > world to find out.
> >
> > The machine in question is:
> >
> > bash-2.05b$ uname -a
> > FreeBSD prolepsis.math.uiuc.edu <http://prolepsis.math.uiuc.edu> <
> http://prolepsis.math.uiuc.edu>
> > 7.0-CURRENTFreeBSD
> > 7.0-CURRENT #9: Thu Aug 25 06:22:00 UTC 2005
> > kaduk at prolepsis.math.uiuc.edu:/usr/obj/usr/src/sys/PROLEPSIS
> > i386
> 
> You should update to a -current which has:
> ---snip---
> $FreeBSD: src/sys/dev/sound/pcm/sound.c,v 1.96 2005/09/12 18:33:33 
> netchild Exp $
> $FreeBSD: src/sys/dev/sound/pcm/dsp.c,v 1.84 2005/09/12 18:33:33 netchild 
> Exp $
> ---snip---
> 
> If it still panics we need to get a backtrace (please have a look at
> the kernel-debugging chapter in the handbook; taking a backtrace isn't
> hard).
> 
> Bye,
> Alexander.
> 
> --
> 0 and 1. Now what could be so hard about that?
> 
> http://www.Leidinger.net Alexander @ Leidinger.net <http://Leidinger.net>
> GPG fingerprint = C518 BC70 E67F 143F BE91 3365 79E2 9C60 B006 3FE7
> 

I upgraded to todays current, with 
$FreeBSD: src/sys/dev/sound/pcm/sound.c,v 1.96 2005/09/12 18:33:33 netchild 
Exp $ and
$FreeBSD: src/sys/dev/sound/pcm/dsp.c,v 1.84 2005/09/12 18:33:33 netchild 
Exp $,
and the panic still occurs, even in single-user. I can dump without 
complaints, but since my /var is only 256 M, I have been manually running 
savecore in single user, saving cores in /usr/crash (perhaps I should try 
with hw.physmem=200M); this latest core seems to have problems:
prolepsis# kgdb /usr/obj/usr/src/sys/PROLEPSIS/kernel.debug 
/usr/crash/vmcore.0
results in a (infinite) loop of:
kgdb: kvm_read: invalid address (0xf0)

so this could be tough to debug. I will try to get an automatic dump on 
/var, and if that fails, set up a serial console and leave the machine in 
the debugger.

Ben Kaduk