Bug#989560: xen-hypervisor-common: generates broken grub configuration on armhf

[Maximilian Engelhardt]

Package: xen-hypervisor-common
Version: 4.14.1+11-gb0b734a8b3-1
Severity: important

Installing xen-system-armhf in a test vm and running update-grub left me with
a grub configuration that cannot boot the xen hypervisor and gets stuck in the
grub menu. It's still possible to boot the normal linux kernel after manual
selection. Grub outputs the following error:


Loading Xen 4.14-armhf ...
error: can't find command `multiboot'.
Loading Linux 5.10.0-7-armmp-lpae ...
error: can't find command `module'.
Loading initial ramdisk ...
error: can't find command `module'.

Press any key to continue...


The problem is that the /etc/grub.d/20_linux_xen file from the grub-common
package generates a multiboot line for the xen hypervisor but there is no
multiboot module available for grub on armhf.

I did a bit research but could not come up with a way to boot the xen
hypervisor from grub on armhf, maybe somebody has more knowledge here.

This may be a bug in 20_linux_xen, but only installing xen-hypervisor-common
causes a not working grub configuration to be generated, so I'm filing this
against this package now. Feel free to reassign.

[Elliott Mitchell]

I rate #989560 as a grub-common bug, *not* a xen-hypervisor-common bug.
As you've noticed, the problem is with the file /etc/grub.d/20_linux_xen,
which is part of grub-common, not xen-hypervisor-common.

A working grub.cfg will be generated by the version of the file from
GRUB 2.04. If you can deal with installing *only* GRUB from testing,
that should work.

The bug should be reassigned to grub-common, but marked as effecting
Xen so duplicate reports don't show up (actually I'm pretty sure reports
against grub-common or src:grub2 already exist).


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[Hans van Kranenburg]

tags 989560 + moreinfo
thanks

Hi,

On 8/4/21 4:00 AM, Elliott Mitchell wrote:
> I rate #989560 as a grub-common bug, *not* a xen-hypervisor-common bug.
> As you've noticed, the problem is with the file /etc/grub.d/20_linux_xen,
> which is part of grub-common, not xen-hypervisor-common.
>
> A working grub.cfg will be generated by the version of the file from
> GRUB 2.04. If you can deal with installing *only* GRUB from testing,
> that should work.
>
> The bug should be reassigned to grub-common, but marked as effecting
> Xen so duplicate reports don't show up (actually I'm pretty sure reports
> against grub-common or src:grub2 already exist).

The /etc/grub.d/20_linux_xen is indeed part of grub-common, but, I'm not
just going to NIMBA reassign, since the grub-common maintainer will not
have any idea what to do with it, unless you guys find out what's wrong
first and have clear directions and questions and patches about how to
improve the situation.

Currently, the only thing I can do before doing new unstable uploads or
stable/security stuff is do smoke testing on amd64.

That doesn't mean I don't care. It does mean however that extra help in
the team is really appreciated.

Have fun,
Hans

[Elliott Mitchell]

Nothing further has been heard. Was bug #989560 resolved by updating to
the GRUB 2.04 packages? Possibly as part of upgrading to bullseye?

The provided information looks like what one might expect from trying to
load Xen on ARM via GRUB 2.02. As such I'm left suspecting this was
resolved by updating.