CVE-2025-38522 sched/ext: Prevent update_locked_rq() calls with NULL rq

In the Linux kernel, the following vulnerability has been resolved: sched/ext: Prevent updatelockedrq calls with NULL rq Avoid invoking updatelockedrq when the runqueue rq pointer is NULL in the SCXCALLOP and SCXCALLOPRET macros. Previously, calling updatelockedrqNULL with preemption enabled coul...