Commit 8b9ad480 authored by Xiaomeng Tong's avatar Xiaomeng Tong Committed by Joerg Roedel
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iommu/msm: Fix an incorrect NULL check on list iterator 



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: f78ebca8 ("iommu/msm: Add support for generic master bindings")
Signed-off-by: default avatarXiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220501132823.12714-1-xiam0nd.tong@gmail.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent bb5bdc5a

drivers/iommu/msm_iommu.c

+7 −4
Original line number Diff line number Diff line
@@ -615,16 +615,19 @@ static int 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;

	}