vulnerability

Red Hat: CVE-2021-47327: kernel: iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails

Severity
5
CVSS
(AV:L/AC:L/Au:M/C:C/I:N/A:P)
Published
May 21, 2024
Added
Jul 9, 2025
Modified
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

no-fix-redhat-rpm-package
Title
NEW

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