[ Added Peter & Greg to Cc ]

Thadeu Lima de Souza Cascardo [off-list ref] writes:

Commit df44b479654f62b478c18ee4d8bc4e9f897a9844 ("kobject: return error
code if writing /sys/.../uevent fails") started returning failure when
writing to /sys/devices/vio/uevent.

This causes an early udevadm trigger to fail. On some installer versions of
Ubuntu, this will cause init to exit, thus panicing the system very early
during boot.

Removing the bus_type from the parent device will remove some of the extra
empty files from /sys/devices/vio/, but will keep the rest of the layout
for vio devices, keeping them under /sys/devices/vio/.

What exactly does it change?

I'm finding it hard to evaluate if this change is going to cause a
regression somehow.

I'm also not clear on why removing the bus type is correct, apart from
whether it fixes the bug you're seeing.

It has been tested that uevents for vio devices don't change after this
fix, they still contain MODALIAS.

Signed-off-by: Thadeu Lima de Souza Cascardo <redacted>
Fixes: df44b479654f ("kobject: return error code if writing /sys/.../uevent fails")

AFAICS there haven't been any other fixes for that commit. Do we know
why it is only vio that was affected? (possibly because it's a fake bus
to begin with?)

cheers