Re: Debootstrap on to Mac SE/30 - strange segfaults
Hi Chris,
On Wed, 6 Mar 2019, Chris Jones wrote:
> Hello Debian-m68k fans. I'm new here and have run in to a strange
> problem installing Debian on my Mac SE/30. Apologies for the long post
> but I've got a lot to report!
>
> Executive summary: I can boot a kernel and run debootstrap
> --second-stage. It starts to unpack packages, but after a few hours
> subprocesses start to fail with segfaults and illegal instructions.
>
I'd say the crashes are caused by filesystem corruption, and the
corruption is caused by an intermittent driver bug. I don't think this is
a Debian bug.
> The setup: Mac SE/30, standard but with 80MB of RAM and a 2GB CF card in
> an Adtron SCSI-to-PCMCIA adapter. Appears to work flawlessly as a Mac
> under System 7.1, hasn't given any hint of trouble.
>
> Me: I'm very used to dealing with embedded Linux systems on armel and
> armhf architectures. Cross-compiling kernels and using debootstrap to
> create root fs is reasonably familiar territory for me.
>
> Install process: CF card partitioned on mac with LIDO, then removed and
> put in to card reader on i386 machine to have files copied on to it
> (kernel on to HFS partition for Penguin, rootfs in to ext3 partition).
>
> Kernel: 4.20.13 crossbuilt from source on kernel.org,with default mac
> config. Earlier kernels all had unusable 5380 SCSI drivers.
Well, there were no relevant changes to the mac_scsi driver since about
v4.9. Therefore, it seems likely that v4.20 has the same driver bug,
albeit an intermittent one.
> Root filesystem set up from image at
> https://cdimage.debian.org/cdimage/ports/9.0/m68k/iso-cd/debian-9.0-m68k-NETINST-1.iso
> using debootstrap --arch m68k --foreign --no-check-gpg sid ... a few
> tweaks to /dev and /etc to get a shell prompt
>
> Boots OK, rootfs mounts OK, kernel finds /bin/sh and I can remount / rw
> and run debootstrap --second-stage. It starts to work, glacially slowly
> of course, but after a few hours (and unpacking a dozen or so packages)
> things start to fail with segfaults and illegal instructions.
>
> After this, the filesystem is hopelessly corrupted, with thousands of
> errors and in one case was unrecoverable by fsck.
>
> My first suspect is bad RAM. For the last 12 hours or so the mac has
> been running memtest 64M (from Woody, I think) under the above kernel.
> It has revealed no errors but hasn't completed a full cycle yet (!).
>
That's possible too, but it probably doesn't explain the "unusable 5380
SCSI drivers" that you observed.
Anyway, I've been working on 5380 driver patches lately so I can easily
send you a new kernel to test if you like.
BTW, you can get a slow but stable 5380 SCSI driver by passing
'mac_scsi.setup_use_pdma=0' in the kernel parameters.
> Why am I using debootstrap? Partly for the sport of it, it's a path I
> know, and I had little luck with the Debian 4.0/etch m68k installer
> which didn't seem to know about Apple Partition Maps so I couldn't
> assign partitions to swap/root and so on.
>
Did you have 'suite=etch-m68k' in the kernel parameters?
> Thank you for any thoughts or experiences,
> Chris
>
HTH
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