From: Chuanhong Guo <gch981213@xxxxxxxxx> [ 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: 38f790a80560 ("net: dsa: mt7530: Add support for port 5") Signed-off-by: Chuanhong Guo <gch981213@xxxxxxxxx> Reviewed-by: Vivien Didelot <vivien.didelot@xxxxxxxxx> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx> Tested-by: René van Dorst <opensource@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/dsa/mt7530.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/net/dsa/mt7530.c +++ b/drivers/net/dsa/mt7530.c @@ -1355,6 +1355,9 @@ mt7530_setup(struct dsa_switch *ds) continue; phy_node = of_parse_phandle(mac_np, "phy-handle", 0); + if (!phy_node) + continue; + if (phy_node->parent == priv->dev->of_node->parent) { ret = of_get_phy_mode(mac_np, &interface); if (ret && ret != -ENODEV)