Hi Chun-Kuang,
On Mon, Oct 06, 2025 at 11:39:37AM +0200, Johan Hovold wrote:
A recent change fixed device reference leaks when looking up drm platform device driver data during bind() but failed to remove a partial fix which had been added by commit 80805b62ea5b ("drm/mediatek: Fix kobject put for component sub-drivers").
This results in a reference imbalance on component bind() failures and on unbind() which could lead to a user-after-free.
Make sure to only drop the references after retrieving the driver data by effectively reverting the previous partial fix.
Note that holding a reference to a device does not prevent its driver data from going away so there is no point in keeping the reference.
Fixes: 1f403699c40f ("drm/mediatek: Fix device/node reference count leaks in mtk_drm_get_all_drm_priv") Reported-by: Sjoerd Simons sjoerd@collabora.com Link: https://lore.kernel.org/r/20251003-mtk-drm-refcount-v1-1-3b3f2813b0db@collab... Cc: stable@vger.kernel.org Cc: Ma Ke make24@iscas.ac.cn Cc: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Signed-off-by: Johan Hovold johan@kernel.org
This patch fixes a regression in 6.17-rc4 that apparently breaks boot for some users. To make things worse, the offending commit was also backported to the stable trees.
You need to get this one into mainline as soon as possible, that is, this week and into 6.18-rc4.
Johan