Re: FYI: Userland breakage caused by udev bind commit

From: Linus Torvalds
Date: Mon Dec 24 2018 - 13:08:47 EST

On Mon, Dec 24, 2018 at 9:34 AM Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> wrote:
> Well, it appears that we can no longer extend uevent interface with new
> types of uevents, at least not until we go and fix up all
> udev-derivatives and give some time for things to settle.

How about having the users "opt in" for new events some way?

Do all the legacy events by default, but then if some user wants a
"bind" event (or some other new event) add a model for the uevent
interface to actually enable it.

Not using kernel versioning (nothing should *ever* look at the kernel
version, since that makes things like backports a huge and
insurmountable pain), but simply using some specific control channel.

> I guess reverting is the right solution here. I wish folks would yell
> earlier though...

So nobody is actually using the new "bind" event, I take it? It's
about a year and a half, and it's in 4.14 which is widely used, so
reverting it has a risk too.

Which is why I too would hope people would be much more vocal about
"that broke my setup".

But reverting does sound like the right thing to do if nobody is using
it. It sounds like systemd udev does not, and if eudev is actively
broken by this then how many other cases might there be?

I assume any locally modified udev rules would still be ok with the
revert (since presumably any udev rule modification people did was to
just ignore the bind/unbind events that no longer would be sent).