linux-kernel - [PATCH v2] media: mtk-mdp: Fix some issues in mtk_mdp

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Message-Id: <20250917094045.28789-1-haoxiang_li2024@163.com>
Date: Wed, 17 Sep 2025 17:40:45 +0800
From: Haoxiang Li <haoxiang_li2024@....com>
To: minghsiu.tsai@...iatek.com,
	houlong.wei@...iatek.com,
	andrew-ct.chen@...iatek.com,
	mchehab@...nel.org,
	matthias.bgg@...il.com,
	angelogioacchino.delregno@...labora.com,
	hans.verkuil@...co.com
Cc: linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org,
	Haoxiang Li <haoxiang_li2024@....com>,
	stable@...r.kernel.org
Subject: [PATCH v2] media: mtk-mdp: Fix some issues in mtk_mdp_core.c

Add check for the return value of vpu_get_plat_device() to prevent null
pointer dereference. And vpu_get_plat_device() increases the reference
count of the returned platform device. Add platform_device_put() to
prevent reference leak. Also add platform_device_put() in mtk_mdp_remove().

Add mtk_mdp_unregister_m2m_device() on the error handling path.

Fixes: c8eb2d7e8202 ("[media] media: Add Mediatek MDP Driver")
Cc: stable@...r.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@....com>
---
Changes in v2:
- Add check for vpu_get_plat_device()
- Add platform_device_put() in mtk_mdp_remove()
- Add mtk_mdp_unregister_m2m_device() on the error handling path.
- Modify the patch title and description. I think you are right.
  Thanks, CJ!
---
 .../media/platform/mediatek/mdp/mtk_mdp_core.c  | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c b/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c
index 80fdc6ff57e0..8432833814f3 100644
--- a/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c
+++ b/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c
@@ -194,11 +194,17 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 	}
 
 	mdp->vpu_dev = vpu_get_plat_device(pdev);
+	if (!mdp->vpu_dev) {
+		dev_err(&pdev->dev, "Failed to get vpu device\n");
+		ret = -ENODEV;
+		goto err_vpu_get_dev;
+	}
+
 	ret = vpu_wdt_reg_handler(mdp->vpu_dev, mtk_mdp_reset_handler, mdp,
 				  VPU_RST_MDP);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to register reset handler\n");
-		goto err_m2m_register;
+		goto err_reg_handler;
 	}
 
 	platform_set_drvdata(pdev, mdp);
@@ -206,7 +212,7 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 	ret = vb2_dma_contig_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32));
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to set vb2 dma mag seg size\n");
-		goto err_m2m_register;
+		goto err_reg_handler;
 	}
 
 	pm_runtime_enable(dev);
@@ -214,6 +220,12 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 
 	return 0;
 
+err_reg_handler:
+	platform_device_put(mdp->vpu_dev);
+
+err_vpu_get_dev:
+	mtk_mdp_unregister_m2m_device(mdp);
+
 err_m2m_register:
 	v4l2_device_unregister(&mdp->v4l2_dev);
 
@@ -242,6 +254,7 @@ static void mtk_mdp_remove(struct platform_device *pdev)
 
 	pm_runtime_disable(&pdev->dev);
 	vb2_dma_contig_clear_max_seg_size(&pdev->dev);
+	platform_device_put(mdp->vpu_dev);
 	mtk_mdp_unregister_m2m_device(mdp);
 	v4l2_device_unregister(&mdp->v4l2_dev);
 
-- 
2.25.1