UBUNTU-CVE-2026-80816: Medium severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: ALSA: FCP: Use a private URB for the notification endpoint fcpinitnotify() used mixer->urb, which sndusbmixerstatuscreate() allocates for the optional UAC2 status interrupt endpoint and mixer.c kills, resubmits and frees. On a device with that endpoint, fcpinitnotify()'s "already set up" early return fires on the status URB and returns success without doing anything. No FCP notification URB is submitted, and cmddone is left zeroed because it is initialised past that early return and nowhere else. fcpinit() then issues init1opcode and waitforcompletiontimeout() would crash adding to the zeroed wait.head. fcpcleanupurb() would also kill and free mixer.c's status URB. Use a separate URB in fcpdata, and initialise cmddone in fcpinitprivate() where fcpdata is allocated. fcpinitnotify() is reached again after suspend via fcpreinit(), and the URB kill path in fcpnotify() completes cmddone, leaving a stale count that would satisfy the next command's wait before the device ACKs. Use reinitcompletion() to clear it.