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iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails 

arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the
refcount of the "smmu" even though the return value is less than 0.

The reference counting issue happens in some error handling paths of
arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get()
fails, the caller functions forget to decrease the refcount of "smmu"
increased by arm_smmu_rpm_get(), causing a refcount leak.

Fix this issue by calling pm_runtime_resume_and_get() instead of
pm_runtime_get_sync() in arm_smmu_rpm_get(), which can keep the refcount
balanced in case of failure.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Link: https://lore.kernel.org/r/1623293672-17954-1-git-send-email-xiyuyang19@fudan.edu.cn
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Xiyu Yang 2021-06-10 10:54:29 +08:00 committed by Will Deacon
parent 22c2d71891
commit 1adf30f198
1 changed files with 1 additions and 1 deletions
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2
drivers/iommu/arm/arm-smmu/arm-smmu.c
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@ -74,7 +74,7 @@ static bool using_legacy_binding, using_generic_binding;
static inline int arm_smmu_rpm_get(struct arm_smmu_device *smmu)
{
if (pm_runtime_enabled(smmu->dev))
return pm_runtime_get_sync(smmu->dev);
return pm_runtime_resume_and_get(smmu->dev);
return 0;
}