[PATCH] drm/mediatek: fix device leaks at bind

[Johan Hovold]

On Fri, Aug 29, 2025 at 07:51:23AM +0800, Chun-Kuang Hu wrote:
> Johan Hovold <johan at kernel.org> 於 2025年8月27日 週三 下午5:51寫道：

> > On Tue, Jul 22, 2025 at 11:27:22AM +0200, Johan Hovold wrote:
> > > Make sure to drop the references to the sibling platform devices and
> > > their child drm devices taken by of_find_device_by_node() and
> > > device_find_child() when initialising the driver data during bind().
> > >
> > > Fixes: 1ef7ed48356c ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support")
> > > Cc: stable at vger.kernel.org    # 6.4
> > > Cc: Nancy.Lin <nancy.lin at mediatek.com>
> > > Signed-off-by: Johan Hovold <johan at kernel.org>
> >
> > Can this one be picked up?
> 
> Ma Ke has sent a similar patch [1] before you. And that patch fix more things.
> I've already pick up the final version [2].
> 
> [1] https://patchwork.kernel.org/project/dri-devel/patch/20250718033226.3390054-1-make24@iscas.ac.cn/
> [2] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/commit/?h=mediatek-drm-fixes-20250825&id=1f403699c40f0806a707a9a6eed3b8904224021a

I'm afraid that patch is completely broken and introduces a potential
use-after-free by adding a bogus decrement of the OF node refcount.

I suggest you drop that one and pick up mine instead which is correct
and cleaner.

Johan