Re: drm panic after new world

On 6/4/25 00:44, Mark Millard wrote:
> Steve Kargl <kargls_at_comcast.net> wrote on
> Date: Wed, 04 Jun 2025 01:45:31 UTC :
>>
>> Well, out of the frying pan and into the fire...
>>
>> Apparently, building world with old src/ on a system
>> running a newer world and installing that old world
>> over the new world is bad. To start install(1) is
>> trying to use a non-existent syscall. Yes, I booted
>> the kernel that matches the old world.
> 
> Did you ever have the newer world booted with the
> older kernel? I cannot tell from the wording.
> That always risks the older kernel not having
> some of what any active parts of the newer world
> needs.

No.  During the boot process, init() dies with a
message that it could not find /bin/sh.  I could
not boot to single-user mode.

> It is newer kernels that allow older worlds
> fairly generally: continuing to support what
> older worlds needed, going back to some point.
> 
> So, I'd expect getting both to be older would
> go more like (but I'm ignoring ports/packages
> for the most part):
> 
> ) Starting having booted newer kernel with newer
>    world (without drm enabled?).

Check.  This was done numerous time in chasing the
drm bug.

> ) (Build and) Install the older world. Make sure
>    no newer drm would be tried on reboot via the
>    older kernel.

This is probably where I messed up as I don't
recall this step.  I built and installed both
old world/kernel on a new world.
> ) Reboot so the startup world processes are also
>    older. This may also be with booting the older
>    kernel or the newer kernel.
> 
> ) If it is an older kernel, build and install
>    a matching drm for the kernel vintage and test
>    it, for example.

Check. I have an old world/kernel with a functioning
drm-515-kmod.

Thanks for warning of the pkg'd files.  The plan was
to use /rescue except it seems that install(1) is not
one of the /rescue tools.  So, now, I'll download a
snapshot circa 2025-03-15 (if I can find one), and
grab the needed files from it.

-- 
steve