In the Linux kernel, the following vulnerability has been resolved:
iommu/amd: Fix pci device refcount leak in ppr_notifier()
As comment of pcigetdomainbusandslot() says, it returns a pci device with refcount increment, when finish using it, the caller must decrement the reference count by calling pcidevput(). So call it before returning from pprnotifier() to avoid refcount leak.