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iommu/msm: Fix an incorrect NULL check on list iterator

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commit 8b9ad480bd 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: f78ebca8ff ("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>
This commit is contained in:
Xiaomeng Tong 2022-05-01 21:28:23 +08:00 committed by Greg Kroah-Hartman
parent 69c14d2972
commit a3f98e4331
1 changed files with 7 additions and 4 deletions
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11
drivers/iommu/msm_iommu.c
View File

@ -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;
}