CVE-2026-43326 sched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback

In the Linux kernel, the following vulnerability has been resolved: schedext: Fix SCXKICKWAIT deadlock by deferring wait to balance callback SCXKICKWAIT busy-waits in kickcpusirqworkfn using smpcondloadacquire until the target CPU's kicksync advances. Because the irqwork runs in hardirq context,...