CVE-2026-99085 sched_ext: Fix CPU hotplug hang when a dying CPU's tasks sit in the BPF scheduler

In the Linux kernel, the following vulnerability has been resolved: schedext: Fix CPU hotplug hang when a dying CPU's tasks sit in the BPF scheduler A CPU going down has to empty its own rq. Its hotplug thread waits in schedcpuwaitempty until nothing else is left, and the only thing that wakes it...