--- x/kernel/workqueue.c
+++ y/kernel/workqueue.c
@@ -2679,7 +2679,8 @@ static void worker_attach_to_pool(struct
 		worker->flags |= WORKER_UNBOUND;
 	} else {
 		WARN_ON_ONCE(pool->flags & POOL_BH);
-		kthread_set_per_cpu(worker->task, pool->cpu);
+		if (!worker->rescue_wq)
+			kthread_set_per_cpu(worker->task, pool->cpu);
 	}
 
 	if (worker->rescue_wq)