linux-kernel - [PATCH 06/14] iommu/mediatek: fix device leaks on probe()

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Message-ID: <20250925122756.10910-7-johan@kernel.org>
Date: Thu, 25 Sep 2025 14:27:48 +0200
From: Johan Hovold <johan@...nel.org>
To: Joerg Roedel <joro@...tes.org>,
	Will Deacon <will@...nel.org>
Cc: Robin Murphy <robin.murphy@....com>,
	Sven Peter <sven@...nel.org>,
	Janne Grunau <j@...nau.net>,
	Rob Clark <robin.clark@....qualcomm.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Yong Wu <yong.wu@...iatek.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Chen-Yu Tsai <wens@...e.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Krishna Reddy <vdumpa@...dia.com>,
	iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	Johan Hovold <johan@...nel.org>,
	stable@...r.kernel.org
Subject: [PATCH 06/14] iommu/mediatek: fix device leaks on probe()

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

Note that commit 26593928564c ("iommu/mediatek: Add error path for loop
of mm_dts_parse") fixed the leaks in a couple of error paths, but the
references are still leaking on success and late failures.

Fixes: 0df4fabe208d ("iommu/mediatek: Add mt8173 IOMMU driver")
Cc: stable@...r.kernel.org	# 4.6
Cc: Yong Wu <yong.wu@...iatek.com>
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/iommu/mtk_iommu.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 8d8e85186188..20a5ba80f983 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1216,13 +1216,17 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 		platform_device_put(plarbdev);
 	}
 
-	if (!frst_avail_smicomm_node)
-		return -EINVAL;
+	if (!frst_avail_smicomm_node) {
+		ret = -EINVAL;
+		goto err_larbdev_put;
+	}
 
 	pcommdev = of_find_device_by_node(frst_avail_smicomm_node);
 	of_node_put(frst_avail_smicomm_node);
-	if (!pcommdev)
-		return -ENODEV;
+	if (!pcommdev) {
+		ret = -ENODEV;
+		goto err_larbdev_put;
+	}
 	data->smicomm_dev = &pcommdev->dev;
 
 	link = device_link_add(data->smicomm_dev, dev,
@@ -1230,7 +1234,8 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 	platform_device_put(pcommdev);
 	if (!link) {
 		dev_err(dev, "Unable to link %s.\n", dev_name(data->smicomm_dev));
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_larbdev_put;
 	}
 	return 0;
 
@@ -1402,8 +1407,12 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 	iommu_device_sysfs_remove(&data->iommu);
 out_list_del:
 	list_del(&data->list);
-	if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM))
+	if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM)) {
 		device_link_remove(data->smicomm_dev, dev);
+
+		for (i = 0; i < MTK_LARB_NR_MAX; i++)
+			put_device(data->larb_imu[i].dev);
+	}
 out_runtime_disable:
 	pm_runtime_disable(dev);
 	return ret;
@@ -1423,6 +1432,9 @@ static void mtk_iommu_remove(struct platform_device *pdev)
 	if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM)) {
 		device_link_remove(data->smicomm_dev, &pdev->dev);
 		component_master_del(&pdev->dev, &mtk_iommu_com_ops);
+
+		for (i = 0; i < MTK_LARB_NR_MAX; i++)
+			put_device(data->larb_imu[i].dev);
 	}
 	pm_runtime_disable(&pdev->dev);
 	for (i = 0; i < data->plat_data->banks_num; i++) {
-- 
2.49.1