savecore: kvm_read: Bad address

[Ray Phillips <r.phillips%uq.edu.au@localhost>]

I built a NetBSD/i386 6.0.1 system, then typed Ctl-Alt-Esc and typed 
`sync' at the db{0}> prompt.  dump succeeded but on the next reboot 
savecore produced errors, as shown below from /var/log/messages:

May  7 18:42:23 ct /netbsd: root on raid0a dumps on raid0b
May  7 18:42:23 ct /netbsd: /: replaying log to memory
May  7 18:42:23 ct /netbsd: root file system type: ffs
May  7 18:42:23 ct /netbsd: /: replaying log to disk
May  7 18:42:23 ct /netbsd: wsdisplay0: screen 1 added (80x25, vt100 emulation)
May  7 18:42:23 ct /netbsd: wsdisplay0: screen 2 added (80x25, vt100 emulation)
May  7 18:42:23 ct /netbsd: wsdisplay0: screen 3 added (80x25, vt100 emulation)
May  7 18:42:23 ct /netbsd: wsdisplay0: screen 4 added (80x25, vt100 emulation)
May  7 18:42:24 ct savecore: reboot after panic: dump forced via 
kernel debugger
May  7 18:42:24 ct savecore: system went down at Tue May  7 18:41:00 2013
May  7 18:42:24 ct savecore: writing compressed core to 
/var/crash/netbsd.1.core.gz
May  7 18:42:34 ct savecore: writing compressed kernel to 
/var/crash/netbsd.1.gz
May  7 18:42:34 ct savecore: kvm_read: kvm_read: Bad address
May  7 18:42:34 ct savecore: (null): Bad address

and /var/run/rc.log:

[failures]
The following components reported failures:
    /etc/rc.d/savecore
See /var/run/rc.log for more information.
[/etc/rc finished at Tue May  7 18:42:42 EST 2013]
[/etc/rc exiting with status 0]

The compressed core file in /var/crash tests OK, but not the compressed kernel:

# gzip -vt netbsd.1.*z
netbsd.1.core.gz:         OK
gzip: netbsd.1.gz: unexpected end of file
gzip: netbsd.1.gz: uncompress failed
netbsd.1.gz:      NOT OK
#

This seems like a potentially serious problem but I don't know how to 
fix it.  I've deleted the disk and reinstalled NetBSD and also tried 
on two other PCs with different disks but it's still happens, so I 
suspect I'm causing it somehow.

When installing NetBSD I used sysinst's suggested size for the swap 
partition--the same as the amount of RAM in the machines.  I believe 
the disks I used are healthy and they had plenty of free space.  Can 
anyone offer some guidance, please?


Ray