1 files changed, 10 insertions, 2 deletions

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 7acc632c3b82..6e52b67b420e 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1051,7 +1051,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group,
 
         if (!rcu_access_pointer(group->poll_kworker)) {
                 struct sched_param param = {
-                        .sched_priority = MAX_RT_PRIO - 1,
+                        .sched_priority = 1,
                 };
                 struct kthread_worker *kworker;
 
@@ -1061,7 +1061,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group,
                         mutex_unlock(&group->trigger_lock);
                         return ERR_CAST(kworker);
                 }
-                sched_setscheduler(kworker->task, SCHED_FIFO, &param);
+                sched_setscheduler_nocheck(kworker->task, SCHED_FIFO, &param);
                 kthread_init_delayed_work(&group->poll_work,
                                 psi_poll_work);
                 rcu_assign_pointer(group->poll_kworker, kworker);
@@ -1131,7 +1131,15 @@ static void psi_trigger_destroy(struct kref *ref)
          * deadlock while waiting for psi_poll_work to acquire trigger_lock
          */
         if (kworker_to_destroy) {
+                /*
+                 * After the RCU grace period has expired, the worker
+                 * can no longer be found through group->poll_kworker.
+                 * But it might have been already scheduled before
+                 * that - deschedule it cleanly before destroying it.
+                 */
                 kthread_cancel_delayed_work_sync(&group->poll_work);
+                atomic_set(&group->poll_scheduled, 0);
+
                 kthread_destroy_worker(kworker_to_destroy);
         }
         kfree(t);