Re: [PATCH v3 0/5] platform/chrome: Fix a possible UAF via revocable

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Fri, Sep 12, 2025 at 04:44:56PM +0200, Bartosz Golaszewski wrote:
> On Fri, Sep 12, 2025 at 4:40 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > Dan's proposal here is a good start, but the "sleep in cdev_del() until
> > the device drains all existing opens" is going to not really work well
> > for what we want.
> >
> > So sure, make a new cdev api to use this, that's fine, then we will have
> > what, 5 different ways to use a cdev?  :)
> >
> > Seriously, that would be good, then we can work to convert things over,
> > but I think overall it will look much the same as what patch 5/5 does
> > here.  But details matter, I don't really known for sure...
> >
> > Either way, I think this patch series stands on its own, it doesn't
> > require cdev to implement it, drivers can use it to wrap a cdev if they
> > want to.  We have other structures that want to do this type of thing
> > today as is proof with the rust implementation for the devm api.
> 
> Yeah, I'm not against this going upstream. If more development is
> needed for this to be usable in other parts of the kernel, that can be
> done gradually. Literally no subsystem ever was perfect on day 1.

To be clear, I'm not against the API being merged for the use cases that
would benefit from it, but I don't want to see drivers using it to
protect from the cdev/unregistration race.

> Tzung-Bi: I'm not sure if you did submit anything but I'd love to see
> this discussed during Linux Plumbers in Tokyo, it's the perfect fit
> for the kernel summit.

-- 
Regards,

Laurent Pinchart