From a3f98e4331e05385c5fc65952ef666c137326bed Mon Sep 17 00:00:00 2001 From: Xiaomeng Tong Date: Sun, 1 May 2022 21:28:23 +0800 Subject: [PATCH] iommu/msm: Fix an incorrect NULL check on list iterator commit 8b9ad480bd1dd25f4ff4854af5685fa334a2f57a upstream. The bug is here: if (!iommu || iommu->dev->of_node != spec->np) { The list iterator value 'iommu' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element is found (in fact, it will point to a invalid structure object containing HEAD). To fix the bug, use a new value 'iter' as the list iterator, while use the old value 'iommu' as a dedicated variable to point to the found one, and remove the unneeded check for 'iommu->dev->of_node != spec->np' outside the loop. Cc: stable@vger.kernel.org Fixes: f78ebca8ff3d6 ("iommu/msm: Add support for generic master bindings") Signed-off-by: Xiaomeng Tong Link: https://lore.kernel.org/r/20220501132823.12714-1-xiam0nd.tong@gmail.com Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/msm_iommu.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c index 3a38352..c9eaf27 100644 --- a/drivers/iommu/msm_iommu.c +++ b/drivers/iommu/msm_iommu.c @@ -615,16 +615,19 @@ static void insert_iommu_master(struct device *dev, static int qcom_iommu_of_xlate(struct device *dev, struct of_phandle_args *spec) { - struct msm_iommu_dev *iommu; + struct msm_iommu_dev *iommu = NULL, *iter; unsigned long flags; int ret = 0; spin_lock_irqsave(&msm_iommu_lock, flags); - list_for_each_entry(iommu, &qcom_iommu_devices, dev_node) - if (iommu->dev->of_node == spec->np) + list_for_each_entry(iter, &qcom_iommu_devices, dev_node) { + if (iter->dev->of_node == spec->np) { + iommu = iter; break; + } + } - if (!iommu || iommu->dev->of_node != spec->np) { + if (!iommu) { ret = -ENODEV; goto fail; } -- 2.7.4