CVE-2022-49016: Missing Release of Memory after Effective Lifetime

In the Linux kernel, the following vulnerability has been resolved:

net: mdiobus: fix unbalanced node reference count

I got the following report while doing device(mscc-miim) load test with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled:

OF: ERROR: memory leak, expected refcount 1 instead of 2, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node /spi/soc@0/mdio@7107009c/ethernet-phy@0

If the 'fwnode' is not an acpi node, the refcount is get in fwnode_mdiobus_phy_device_register(), but it has never been put when the device is freed in the normal path. So call fwnode_handle_put() in phy_device_release() to avoid leak.

If it's an acpi node, it has never been get, but it's put in the error path, so call fwnode_handle_get() before phy_device_register() to keep get/put operation balanced.