[PATCH] udev: add tags also on bind action

[Aleksander Morgado]

Hey!

On Sun, May 27, 2018 at 6:16 PM, Bjørn Mork <bjorn at mork.no> wrote:
> Never heard of "bind" events before.  Googling them led me straight to
> https://github.com/systemd/systemd/issues/8221
> which tells me that that I haven't been paying much attention for the
> last 5 kernel releases...
>
> Except for that, this looks like a systemd bug.  The Debian bug is
> reported agains v237, so your v236 will be affected.
>

Ohh, this explains everything I'm seeing indeed.

> I will test your patch, but adding "bind" to every existing rule for
> every device and every application cannot be right?  This should be
> handled by systemd-udev.
>

Yes, should be handled by systemd-udev, definitely. This is extremely
unfortunate...

But in the meantime, all the logic we have in place to handle udev
tags at device level are affected. The udev tags we set for e.g.
tagging port types aren't affected (as there's no bind event for the
tty device), but all the udev tags for the blacklist and greylist are
affected currently. So I believe there's something we need to do...
maybe adding the tag on the bind event is overkill?

There's another possibility that I see we could use, and that would be
not to tag the device, but tag all the ports of the device instead.
This is already supported in git master because the "udev-less" logic
used in OpenWRT applies device-level tags in the different ports, so
we could do the same to avoid this... The problem is that this would
force us to keep this in place forever I guess... and that brings me
back to thinking just adding the rules also in bind wouldn't be that
bad.

Note anyway, that this udev bug affects MM running in DEFAULT filter
mode. If using the STRICT filter, as we're suggesting all
distributions to use now, they would not be affected (as all
port-level udev tags wouldn't be affected, and there's no
blacklist/greylist filtering in STRICT mode).

Well, a third option would be to hack our own port type rules,
blacklist, greylist... without using udev at all. But I really
wouldn't want to have to do that right now...

Whenever we find a solution for this issue in our side, even if
temporary, I'll suggest we release 1.8.

-- 
Aleksander
https://aleksander.es