[PATCH v2 04/10] um: change machine name for uname output

[Johannes Berg]

On Fri, 2026-07-24 at 15:50 +0900, Hajime Tazaki wrote:
> On Thu, 23 Jul 2026 18:35:45 +0900,
> Johannes Berg wrote:
> > 
> > From: Hajime Tazaki <thehajime at gmail.com>
> > 
> > This commit tries to display MMU/!MMU mode from the output of uname(2)
> > so that users can distinguish which mode of UML is running right now.
> > 
> > Signed-off-by: Hajime Tazaki <thehajime at gmail.com>
> > [remove / to fix regression with systemd userspace]
> > Signed-off-by: Johannes Berg <johannes.berg at intel.com>
> > ---
> > v2: regression fix
> 
> I'd like to know what kind of regression did you see.

With your original change, systemd doesn't boot, it asserts here:
https://github.com/systemd/systemd/blob/main/src/basic/architecture.c#L136

> with only this diff, there is no visible changes with uname command on
> UML (both mmu/nommu), as setup_machinename() overwrite this.

Oops. I never tested it, sorry. Just saw the boot failure with my
standard 64-bit (and maybe 32-bit as well?) boot test filesystems.

> maybe we could drop this patch if we cannot put a name 'um' in the
> machine name ?

Sure, we can drop it. Or arrange so only nommu is different? Or even
call it SUBARCH-nommu?

johannes