Medium [CVE-2026-64338] unregister parport on probe failure

In the Linux kernel, the following vulnerability has been resolved: USB: misc: uss720: unregister parport on probe failure uss720_probe() registers a parport before reading the 1284 register used to detect unsupported Belkin F5U002 adapters.

If get_1284_register() fails, the error path drops the driver private data and the USB device reference, but leaves the parport device registered.

Leaving the port registered is more than a private allocation leak: parport_register_port() has already reserved a parport number and registered the parport bus device, while pp->private_data still points at the private data that the common error path is about to release.

Undo the pre-announce registration in the get_1284_register() failure branch before jumping to the common private-data cleanup path. Clear priv->pp first, matching the disconnect path and avoiding a stale pointer in the private data.

This issue was identified during our ongoing static-analysis research while reviewing kernel code. When the `uss720_probe()` function attempts to initialize a USB parallel port (parport) device, it registers the parport but may fail to unregister it if a subsequent hardware register read operation fails.

Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 9; Red Hat package: kernel-rt.