vulnerability
Red Hat: CVE-2021-47327: kernel: iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 5 | (AV:L/AC:L/Au:M/C:C/I:N/A:P) | May 21, 2024 | Jul 9, 2025 | Jul 10, 2025 |
Description
In the Linux kernel, the following vulnerability has been resolved:
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.
Solution
References
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