The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x de83d4617f9fe059623e97acf7e1e10d209625b5 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025122941-reluctant-exhale-a49f@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From de83d4617f9fe059623e97acf7e1e10d209625b5 Mon Sep 17 00:00:00 2001 From: Johan Hovold johan@kernel.org Date: Mon, 20 Oct 2025 06:53:10 +0200 Subject: [PATCH] iommu/mediatek: fix use-after-free on probe deferral
The driver is dropping the references taken to the larb devices during probe after successful lookup as well as on errors. This can potentially lead to a use-after-free in case a larb device has not yet been bound to its driver so that the iommu driver probe defers.
Fix this by keeping the references as expected while the iommu driver is bound.
Fixes: 26593928564c ("iommu/mediatek: Add error path for loop of mm_dts_parse") Cc: stable@vger.kernel.org Cc: Yong Wu yong.wu@mediatek.com Acked-by: Robin Murphy robin.murphy@arm.com Signed-off-by: Johan Hovold johan@kernel.org Reviewed-by: Yong Wu yong.wu@mediatek.com Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Signed-off-by: Joerg Roedel joerg.roedel@amd.com
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c index 82a55fe19a62..54d8936d9d11 100644 --- a/drivers/iommu/mtk_iommu.c +++ b/drivers/iommu/mtk_iommu.c @@ -1213,16 +1213,19 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m }
component_match_add(dev, match, component_compare_dev, &plarbdev->dev); - 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 +1233,8 @@ 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 +1406,12 @@ 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 +1431,9 @@ 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++) {