From: Chuanhong Guo <gch981213@gmail.com>
Date: Fri, 3 Apr 2020 11:28:24 +0000 (+0800)
Subject: net: dsa: mt7530: fix null pointer dereferencing in port5 setup
X-Git-Tag: v5.5.17~40
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4c0fc5b184fc589b7b993411a7162f72c4660593;p=thirdparty%2Fkernel%2Fstable.git

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: 38f790a80560 ("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>
---

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 60a8a68567baa..936b9b65accab 100644
--- 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)