In the Linux kernel, the following vulnerability has been resolved: hwmon: (coretemp) fix pci device refcount leak in nv1a_ram_new() As comment of pci_get_domain_bus_and_slot() says, it returns a pci device with refcount increment, when finish using it, the caller must decrement the reference count by calling pci_dev_put(). So call it after using to avoid refcount leak.