From: Xiaomeng Tong xiam0nd.tong@gmail.com
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 xiam0nd.tong@gmail.com Link: https://lore.kernel.org/r/20220501132823.12714-1-xiam0nd.tong@gmail.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/msm_iommu.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
--- a/drivers/iommu/msm_iommu.c +++ b/drivers/iommu/msm_iommu.c @@ -636,16 +636,19 @@ static void insert_iommu_master(struct d 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; }