sched: Fix sched_delayed vs sched_core

Completely analogous to commit dfa0a57 ("sched/uclamg: Handle
delayed dequeue"), avoid double dequeue for the sched_core entries.

Fixes: 152e11f ("sched/fair: Implement delayed dequeue")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Author: Peter Zijlstra

kernel/sched/core.c

@@ -259,6 +259,9 @@ static inline int rb_sched_core_cmp(const void *key, const struct rb_node *node)
 
 void sched_core_enqueue(struct rq *rq, struct task_struct *p)
 {
+	if (p->se.sched_delayed)
+		return;
+
 	rq->core->core_task_seq++;
 
 	if (!p->core_cookie)
@@ -269,6 +272,9 @@ void sched_core_enqueue(struct rq *rq, struct task_struct *p)
 
 void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags)
 {
+	if (p->se.sched_delayed)
+		return;
+
 	rq->core->core_task_seq++;
 
 	if (sched_core_enqueued(p)) {