A reference counting issue in the Linux kernel's iommu/arm-smmu component causes a refcount leak when `arm smmu rpm get()` fails. The `arm smmu rpm get()` function invokes `pm runtime get sync()`, increasing the refcount of the "smmu" even if the return value is less than 0. This issue occurs in some error handling paths of `arm smmu rpm get()` in its caller functions, where the refcount of "smmu" is not decreased when `arm smmu rpm get()` fails. To fix this issue, `pm runtime resume and get()` is called instead of `pm runtime get sync()` in `arm smmu rpm get()`, keeping the refcount balanced in case of failure.