sched: Switch rq->next_class on proxy_resched_idle()

K Prateek noticed we weren't setting the rq->next_class in
proxy_resched_idle(), when I was debugging an issue seen with
CONFIG_SCHED_PROXY_EXEC and some of Peter's new patches, and
suggested this fix.

So set rq->next_class when we temporarily switch the donor to
idle, so we don't accidentally call wakeup_preempt_fair()
with idle as the donor.

Suggested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260514234732.3170197-1-jstultz@google.com

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3ae5f19c1b7eb197f69baffc474e87e139ea0a46..77f4ebe8f5c7b196e8adb2a2c5c2204d12eb6780 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6653,6 +6653,7 @@ static inline void proxy_set_task_cpu(struct task_struct *p, int cpu)
 static inline struct task_struct *proxy_resched_idle(struct rq *rq)
 {
        put_prev_set_next_task(rq, rq->donor, rq->idle);
+       rq->next_class = &idle_sched_class;
        rq_set_donor(rq, rq->idle);
        set_tsk_need_resched(rq->idle);
        return rq->idle;