CVE-2021-47327 Information

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\nincreased 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.

Reference

https://git.kernel.org/stable/c/3761ae0d0e549f2acdaf11f49df4ed06d256b20f https://git.kernel.org/stable/c/c4007596fbdabc29f858dc2e1990858a146b60b2 https://git.kernel.org/stable/c/fbf4daa6f4105e01fbd3868006f65c163365c1e3 https://git.kernel.org/stable/c/fe92c058199067ae90cf2a901ddf3c271893557a https://git.kernel.org/stable/c/1adf30f198c26539a62d761e45af72cde570413d