Subject: Re: port-i386/7608: i386 1.4 sysinst upgrade fall down go BOOM!
To: None <firstname.lastname@example.org>
From: Chris G. Demetriou <email@example.com>
Date: 06/18/1999 01:06:24
> sysinst blew up (Floating Point Exception, core dump) after
> installing the installation binaries on the hard disk and running
> installboot. I ran sysinst with logging and scripting turned
> on, and the last thing in the script was:
I investigated this some more.
The problem is trivially reproducable (if you have a disk to nuke 8-):
* boot the 1.3.2 install floppy, install NetBSD.
standard + x, whole disk. have it clobber the disk.
when it gets to the point of trying to install sets,
* boot the 1.4 install floppy, upgrade. follow the prompts,
I dug into the problem some more, and found that when writing the
upgraded MBR, convert_mbr_chs() was called with cyl == head == sec ==
0. Since these arguments' values come from globals which are
initialized when the BIOS geometry is figured in md_bios_info(), it
would seem that md_bios_info() should be being called but isn't.
Unfortunately, I'm not really familiar enough with the way this should
work to know where it should be called. (However, this doesn't sound
like a configuration-specific bug... was the upgrade code _ever_
tested by the people hacking on it?!)
Things which I noticed which also caused me concern:
in md_upgrade_mbrtype(), read_mbr() is called. If an error occurs
md_upgrade_mbrtype gives up (but doesn't signal an error -- should it
be able to? probably it should be _able_ to, if not for this case
then for the case where write_mbr fails). However, if no error occurs
bu the MBR is not actually valid, it continues merrily along. It's
not clear to me that this is 'right'.
in md_get_info(), the return value from read_mbr() is ignored
completely, but valid_mbr() is checked... This seems like it might be
OK, but consistency and carefulness are better than the lack
Chris Demetriou - firstname.lastname@example.org - http://www.netbsd.org/People/Pages/cgd.html
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.