CVE-2026-64029 ALSA: seq: Serialize UMP output teardown with event_input

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize UMP output teardown with eventinput sequmpprocessevent borrows client-outrfile.output without synchronizing with the first-open and last-close transition in sequmpclientopen and sequmpclientclose. The last...