Commit 7d3d99f5 authored Apr 03, 2020 by Chuanhong Guo Committed by Greg Kroah-Hartman Apr 13, 2020

net: dsa: mt7530: fix null pointer dereferencing in port5 setup



[ Upstream commit 0452800f6db4ed0a42ffb15867c0acfd68829f6a ]

The 2nd gmac of mediatek soc ethernet may not be connected to a PHY
and a phy-handle isn't always available.
Unfortunately, mt7530 dsa driver assumes that the 2nd gmac is always
connected to switch port 5 and setup mt7530 according to phy address
of 2nd gmac node, causing null pointer dereferencing when phy-handle
isn't defined in dts.
This commit fix this setup code by checking return value of
of_parse_phandle before using it.

Fixes: 38f790a8 ("net: dsa: mt7530: Add support for port 5")
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: René van Dorst <opensource@vdorst.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent bce7ce18

drivers/net/dsa/mt7530.c

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1353,6 +1353,9 @@ mt7530_setup(struct dsa_switch *ds)
	continue;		continue;

	phy_node = of_parse_phandle(mac_np, "phy-handle", 0);		phy_node = of_parse_phandle(mac_np, "phy-handle", 0);
			if (!phy_node)
			continue;

	if (phy_node->parent == priv->dev->of_node->parent) {		if (phy_node->parent == priv->dev->of_node->parent) {
	interface = of_get_phy_mode(mac_np);		interface = of_get_phy_mode(mac_np);
	id = of_mdio_parse_addr(ds->dev, phy_node);		id = of_mdio_parse_addr(ds->dev, phy_node);