From: Xiaomeng Tong <xiam0nd.tong@gmail.com>
To: agross@kernel.org, bjorn.andersson@linaro.org, joro@8bytes.org,
will@kernel.org, sricharan@codeaurora.org
Cc: linux-arm-msm@vger.kernel.org, iommu@lists.linux-foundation.org,
Xiaomeng Tong <xiam0nd.tong@gmail.com>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: [PATCH v2] iommu: fix an incorrect NULL check on list iterator
Date: Sun, 1 May 2022 21:28:23 +0800 [thread overview]
Message-ID: <20220501132823.12714-1-xiam0nd.tong@gmail.com> (raw)
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>
---
changes since v1:
- add a new iter variable (suggested by Joerg Roedel)
v1: https://lore.kernel.org/all/20220327053558.2821-1-xiam0nd.tong@gmail.com/
---
drivers/iommu/msm_iommu.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index 3a38352b603f..41a3231a6d13 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -615,16 +615,17 @@ 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;
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;
}
--
2.17.1
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next reply other threads:[~2022-05-01 13:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-01 13:28 Xiaomeng Tong [this message]
2022-05-04 8:49 ` [PATCH v2] iommu: fix an incorrect NULL check on list iterator Joerg Roedel
-- strict thread matches above, loose matches on Subject: below --
2022-05-01 13:12 Xiaomeng Tong
2022-05-02 9:13 ` kernel test robot
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