diff --git a/drivers/md/md.c b/drivers/md/md.c
index 89d4dcc5253e..f8c111b36992 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2991,6 +2991,9 @@ slot_store(struct md_rdev *rdev, const char *buf, size_t len)
 		err = kstrtouint(buf, 10, (unsigned int *)&slot);
 		if (err < 0)
 			return err;
+		if (slot < 0)
+			/* overflow */
+			return -ENOSPC;
 	}
 	if (rdev->mddev->pers && slot == -1) {
 		/* Setting 'slot' on an active array requires also