diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 18c5a9bb6759..ce5d3e9e5dff 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3739,6 +3739,7 @@ static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 	int txfifosz = priv->plat->tx_fifo_size;
+	const int mtu = new_mtu;
 
 	if (txfifosz == 0)
 		txfifosz = priv->dma_cap.tx_fifo_size;
@@ -3756,7 +3757,7 @@ static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
 	if ((txfifosz < new_mtu) || (new_mtu > BUF_SIZE_16KiB))
 		return -EINVAL;
 
-	dev->mtu = new_mtu;
+	dev->mtu = mtu;
 
 	netdev_update_features(dev);