net: bcmgenet: fix OF child-node lookup

[ Upstream commit d397dbe606120a1ea1b11b0020c3f7a3852da5ac ]

Use the new of_get_compatible_child() helper to lookup the mdio child
node instead of using of_find_compatible_node(), which searches the
entire tree from a given start node and thus can return an unrelated
(i.e. non-child) node.

This also addresses a potential use-after-free (e.g. after probe
deferral) as the tree-wide helper drops a reference to its first
argument (i.e. the node of the device being probed).

Fixes: aa09677cba42 ("net: bcmgenet: add MDIO routines")
Cc: stable <stable@vger.kernel.org>     # 3.15
Cc: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index abbd289..c421e27 100644 (file)
--- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
@@ -360,7 +360,7 @@ static struct device_node *bcmgenet_mii_of_find_mdio(struct bcmgenet_priv *priv)
        if (!compat)
                return NULL;
 
-       priv->mdio_dn = of_find_compatible_node(dn, NULL, compat);
+       priv->mdio_dn = of_get_compatible_child(dn, compat);
        kfree(compat);
        if (!priv->mdio_dn) {
                dev_err(kdev, "unable to find MDIO bus node\n");