diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0f7115b31ca3..118de338266a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -414,6 +414,20 @@ bool md_handle_request(struct mddev *mddev, struct bio *bio)
 		if (!percpu_ref_tryget_live(&mddev->active_io))
 			goto check_suspended;
 	}
+	if (!mddev->pers) {
+		/*
+		 * The __md_stop() sets 'mddev->private' to NULL during
+		 * the IO submitting, check 'mddev->pers' before the IO
+		 * being processed by specific driver to avoid the
+		 * null-ptr-deref of 'mddev-><member>'. The check is
+		 * safe because the IO has got the 'mddev->active_io'
+		 * reference, and all __md_stop() callers will wait for
+		 * the reference to be zero.
+		 */
+		bio_io_error(bio);
+		percpu_ref_put(&mddev->active_io);
+		return true;
+	}
 	if (!mddev->pers->make_request(mddev, bio)) {
 		percpu_ref_put(&mddev->active_io);
 		if (mddev_is_dm(mddev) && mddev->pers->prepare_suspend)
@@ -4670,7 +4684,8 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
 	case readonly:
 	case inactive:
 	case read_auto:
-		if (!mddev->pers || !md_is_rdwr(mddev))
+		if (!mddev->pers ||
+		    (st != clear && st != inactive && !md_is_rdwr(mddev)))
 			break;
 		/* write sysfs will not open mddev and opener should be 0 */
 		err = mddev_set_closing_and_sync_blockdev(mddev, 0);
@@ -8299,6 +8314,7 @@ static bool md_ioctl_need_suspend(unsigned int cmd)
 	case HOT_REMOVE_DISK:
 	case SET_BITMAP_FILE:
 	case SET_ARRAY_INFO:
+	case STOP_ARRAY:
 		return true;
 	default:
 		return false;