diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 669aef77a0bd0e2a5bcbcaba7cd6938b2e301ade..c37d2657308cd7062a5ff1d49740e63149e0e93e 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1237,14 +1237,16 @@ static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
 {
 	struct tty_struct *tty;
 
-	if (driver->ops->lookup)
+	if (driver->ops->lookup) {
 		if (!file)
 			tty = ERR_PTR(-EIO);
 		else
 			tty = driver->ops->lookup(driver, file, idx);
-	else
+	} else {
+		if (idx >= driver->num)
+			return ERR_PTR(-EINVAL);
 		tty = driver->ttys[idx];
-
+	}
 	if (!IS_ERR(tty))
 		tty_kref_get(tty);
 	return tty;