Panic on boot from CD

[Tim Simmons]

I only have the one mac in here that I can use, and since I don't have an OS
with a working compiler on it, I'm afraid I can't do much in the way of code
hacking. 

Tim Simmons
IT Technician
Champion Realty, Inc.
TimSimmons at ChampionRealty.Com
Direct:410-975-3028
Fax: 410-647-1187

-----Original Message-----
From: John Baldwin [mailto:jhb at freebsd.org] 
Sent: Thursday, October 13, 2005 11:34 AM
To: freebsd-ppc at freebsd.org
Cc: Tim Simmons; 'Peter Grehan'
Subject: Re: Panic on boot from CD

On Thursday 13 October 2005 10:33 am, Tim Simmons wrote:
> Sorry it's taken me a while to respond, I've been out on family leave. I
> have tried as you suggested, booting from the open firmware screen instead
> of directly from the CD, and I get the same result.
>
> I downloaded and burned the 6.0RC1 ISO this morning, and get a slightly
> different error, but in the same place. The error now reads:
>
> KDB: debugger backends: ddb
> KDB: current backend: ddb
> Panic: Assertion curthread != NULL failed at
> /usr/src/sys/kern/kern_mutex.c:268
>
> KDB: enter: panic
> [thread pid -1 tid 0 ]
> Stopped at 	0:	illegal instruction 0
> Db>
>
>
> I can't interact with the system at this point to run a stack trace. Any
> ideas? Oh, and no, it's not an eMac. It's a PowerMac G4 667mhz w/ 256 megs
> ram. This same machine runs fine under OSX.

curthread of NULL would certainly indicate that mtx_lock() is being called 
before mutex_init().  If there's any way to get a stack trace, that would be

helpful.  Alternatively, you can try inserting a while (1); hang in the code

prior to the call to mutex_init() and move it around until you find out
where 
the hang is.  However, looking in powerpc_init(), it seems that kdb_init() 
(which does the KDB printf's) doesn't get called until after mutex_init(),
so 
it seems that curthread is getting reset to NULL after it was initially set 
before mutex_init().

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org