Re: [PATCH 1/9] drm/connector: Make the drm_sysfs connector->kdev device hold a reference to the connector

p.s.

On 4/30/21 1:38 PM, Daniel Vetter wrote:

Offtopic:

I'm also not sure why we have to use the kdev stuff here. For other
random objects we need to look up we're building that functionality on
that object. It means you need to keep another list_head around for
that lookup, but that's really not a big cost. E.g. drm_bridge/panel
work like that.

So I took a peek at the bridge/panel code and that actually seems to
have an issue with removal vs lookup. It is not even just a race,
it seems a lookup does not take a reference and there is nothing
stopping a user from doing an unbind or rmmod causing the panel
to be removed while other code which got a pointer to the panel
through of_drm_find_panel() will not be prepared to deal with
that pointer all of a sudden no longer being valid.

Now this would be a case of the user shooting his-self in the
foot (where as connectors can actually dynamically disappear
under normal circumstances), but ideally we really should do
better here.

Is there a TODO list somewhere for issues like this ?  Or shall
I submit a patch adding a FIXME comment, or is this considered
not worth the trouble of fixing it?

Regards,

Hans