CVE-2026-98463

In the Linux kernel, the following vulnerability has been resolved:

sched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags

schedule_deferred_locked() skips scheduling a deferred action while

SCX_RQ_IN_WAKEUP is set and relies on the task_woken_scx() call that follows

a wakeup enqueue to run it. enqueue_task_scx() sets the flag from the merged

enqueue flags, which include the flags stashed for a remote activation.

move_remote_task_to_local_dsq() thus sets SCX_RQ_IN_WAKEUP on the

destination rq when the moved task was woken up, although no

task_woken_scx() follows that activation.

An IMMED insert into a busy destination requests a local reenqueue during

that enqueue. The request gets linked but not scheduled and stays pending

until an unrelated wakeup or preemption on that CPU runs the deferred

actions. The IMMED task sits behind the running task in the meantime. If

nothing runs them before the scheduler is disabled, the request outlives the

scheduler and points into its freed per-cpu area, which the next scheduler

dereferences from run_deferred().

Test the core enqueue flags for the wakeup bit. Only the core's wakeup path

is followed by task_woken_scx().