6.6-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
commit de83d4617f9fe059623e97acf7e1e10d209625b5 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/mtk_iommu.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-)
--- a/drivers/iommu/mtk_iommu.c +++ b/drivers/iommu/mtk_iommu.c @@ -1196,16 +1196,19 @@ static int mtk_iommu_mm_dts_parse(struct }
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, @@ -1213,7 +1216,8 @@ static int mtk_iommu_mm_dts_parse(struct 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;
@@ -1385,8 +1389,12 @@ out_sysfs_remove: 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; @@ -1406,6 +1414,9 @@ static void mtk_iommu_remove(struct plat 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++) {