target/linux/generic/backport-5.4/746-stable-net-dsa-mt7530-fix-null-pointer-dereferencing-in-por.patch

   1 From 0452800f6db4ed0a42ffb15867c0acfd68829f6a Mon Sep 17 00:00:00 2001
   2 From: Chuanhong Guo <gch981213@gmail.com>
   3 Date: Fri, 3 Apr 2020 19:28:24 +0800
   4 Subject: net: dsa: mt7530: fix null pointer dereferencing in port5 setup
   5 MIME-Version: 1.0
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   8
   9 The 2nd gmac of mediatek soc ethernet may not be connected to a PHY
  10 and a phy-handle isn't always available.
  11 Unfortunately, mt7530 dsa driver assumes that the 2nd gmac is always
  12 connected to switch port 5 and setup mt7530 according to phy address
  13 of 2nd gmac node, causing null pointer dereferencing when phy-handle
  14 isn't defined in dts.
  15 This commit fix this setup code by checking return value of
  16 of_parse_phandle before using it.
  17
  18 Fixes: 38f790a80560 ("net: dsa: mt7530: Add support for port 5")
  19 Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
  20 Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
  21 Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
  22 Tested-by: René van Dorst <opensource@vdorst.com>
  23 Signed-off-by: David S. Miller <davem@davemloft.net>
  24 ---
  25  drivers/net/dsa/mt7530.c | 3 +++
  26  1 file changed, 3 insertions(+)
  27
  28 --- a/drivers/net/dsa/mt7530.c
  29 +++ b/drivers/net/dsa/mt7530.c
  30 @@ -1411,6 +1411,9 @@ mt7530_setup(struct dsa_switch *ds)
  31                                 continue;
  32
  33                         phy_node = of_parse_phandle(mac_np, "phy-handle", 0);
  34 +                       if (!phy_node)
  35 +                               continue;
  36 +
  37                         if (phy_node->parent == priv->dev->of_node->parent) {
  38                                 interface = of_get_phy_mode(mac_np);
  39                                 id = of_mdio_parse_addr(ds->dev, phy_node);