[PATCH] media: platform: mtk-mdp3: fix device leaks at probe

[PATCH] media: platform: mtk-mdp3: fix device leaks at probe

[Johan Hovold]

Make sure to drop the references taken when looking up the subsys
devices during probe on probe failure (e.g. probe deferral) and on
driver unbind.

Similarly, drop the SCP device reference after retrieving its platform
data during probe to avoid leaking it.

Note that holding a reference to a device does not prevent its driver
data from going away.

Fixes: 61890ccaefaf ("media: platform: mtk-mdp3: add MediaTek MDP3 driver")
Cc: stable@vger.kernel.org	# 6.1
Cc: Moudy Ho <moudy.ho@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 .../media/platform/mediatek/mdp3/mtk-mdp3-core.c   | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c
index 8de2c8e4d333..fc117a6a822c 100644
--- a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c
+++ b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c
@@ -157,10 +157,18 @@ void mdp_video_device_release(struct video_device *vdev)
 	kfree(mdp);
 }
 
+static void mdp_put_device(void *_dev)
+{
+	struct device *dev = _dev;
+
+	put_device(dev);
+}
+
 static int mdp_mm_subsys_deploy(struct mdp_dev *mdp, enum mdp_infra_id id)
 {
 	struct platform_device *mm_pdev = NULL;
 	struct device **dev;
+	int ret;
 	int i;
 
 	if (!mdp)
@@ -194,6 +202,11 @@ static int mdp_mm_subsys_deploy(struct mdp_dev *mdp, enum mdp_infra_id id)
 		if (WARN_ON(!mm_pdev))
 			return -ENODEV;
 
+		ret = devm_add_action_or_reset(&mdp->pdev->dev, mdp_put_device,
+					       &mm_pdev->dev);
+		if (ret)
+			return ret;
+
 		*dev = &mm_pdev->dev;
 	}
 
@@ -279,6 +292,7 @@ static int mdp_probe(struct platform_device *pdev)
 			goto err_destroy_clock_wq;
 		}
 		mdp->scp = platform_get_drvdata(mm_pdev);
+		put_device(&mm_pdev->dev);
 	}
 
 	mdp->rproc_handle = scp_get_rproc(mdp->scp);
-- 
2.49.1

Re: [PATCH] media: platform: mtk-mdp3: fix device leaks at probe

[AngeloGioacchino Del Regno]

Il 24/09/25 16:39, Johan Hovold ha scritto:
> Make sure to drop the references taken when looking up the subsys
> devices during probe on probe failure (e.g. probe deferral) and on
> driver unbind.
> 
> Similarly, drop the SCP device reference after retrieving its platform
> data during probe to avoid leaking it.
> 
> Note that holding a reference to a device does not prevent its driver
> data from going away.
> 
> Fixes: 61890ccaefaf ("media: platform: mtk-mdp3: add MediaTek MDP3 driver")
> Cc: stable@vger.kernel.org	# 6.1
> Cc: Moudy Ho <moudy.ho@mediatek.com>
> Signed-off-by: Johan Hovold <johan@kernel.org>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>