Two more thoughts:
		a) Does the problem happen in single user mode?
		b) How about single user mode booting a 1.2.1 kernel
		   (This is an ok thing to do)

                David/abs               abs@anim.dreamworks.com

.---- I've been too drunk to love ----.-- I've been too drunk to remember -.
|          too drunk to care          |    the hell of the night before    |
|  looked like death, felt like hell  |   I've been drinking myself blind  |
`------ been the worse for wear ------'-- and still I'll drink some more --'

On Sat, 17 May 1997, Rick Byers wrote:

> Yes, since the disks couldn't sync after the panic, it did fschk
> everything.  There were a few minor errors, but I didn't see anything out
> of the ordinary for a crash during heavy disk activity.
> 
> Rick
> 
> On Sat, 17 May 1997, David Brownlee wrote:
> 
> > 	Have you tried running fsck -f on the filesystems after the
> > 	problem? (If you boot to multi user it will probably happen
> > 	anyway, but its always worth checking :)
> > 
> >                 David/abs               abs@anim.dreamworks.com
> > 
> > .---- I've been too drunk to love ----.-- I've been too drunk to remember -.
> > |          too drunk to care          |    the hell of the night before    |
> > |  looked like death, felt like hell  |   I've been drinking myself blind  |
> > `------ been the worse for wear ------'-- and still I'll drink some more --'
> > 
> > On Sat, 17 May 1997, Rick Byers wrote:
> > 
> > > Hi All,
> > > I'm in the process of upgrading a 1.2/i386 machine to 1.2.1.  While moving
> > > about a gig of data (users home dir's) over, I've gotten the following
> > > panic twice so far.
> > > 
> > > block 4135
> > > Panic: blkfree: freeing free frag
> > > 
> > > It then fails to sync the disks, but does do a core dump.  I don't have
> > > debugging symbols compiled into the kernel, so gdb isn't much help.  The
> > > only thing I noticed in gdb is that backtrace gives "cannot access memory
> > > at 0x0".  
> > > 
> > > Anyway, is this most likely a hardware problem or a netbsd bug?  I'm
> > > hoping that it is a bug that is fixed in 1.2.1.  What are the major
> > > changes in 1.2.1 anyway (still can't find a CHANGES file)?
> > > 
> > > Thanks,
> > > 	Rick
> > > 
> > > =========================================================================
> > > Rick Byers                                      Internet Access Worldwide
> > > rickb@iaw.on.ca                                System Admin, Tech Support
> > > Welland, Ontario, Canada                                    (905)714-1400
> > > http://www.iaw.on.ca/rickb/                         http://www.iaw.on.ca/
> > > 
> > 
> 
> =========================================================================
> Rick Byers                                      Internet Access Worldwide
> rickb@iaw.on.ca                                System Admin, Tech Support
> Welland, Ontario, Canada                                    (905)714-1400
> http://www.iaw.on.ca/rickb/                         http://www.iaw.on.ca/
>