[PATCH 4.4 27/86] net: bcmgenet: fix OF child-node lookup

From: Greg Kroah-Hartman
Date: Thu Nov 29 2018 - 10:02:13 EST

4.4-stable review patch. If anyone has any objections, please let me know.


[ 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@xxxxxxxxxxxxxxx> # 3.15
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/net/ethernet/broadcom/genet/bcmmii.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index 4c73feca4842..0565efad6e6e 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
@@ -491,7 +491,7 @@ static int bcmgenet_mii_of_init(struct bcmgenet_priv *priv)
if (!compat)
return -ENOMEM;

- priv->mdio_dn = of_find_compatible_node(dn, NULL, compat);
+ priv->mdio_dn = of_get_compatible_child(dn, compat);
if (!priv->mdio_dn) {
dev_err(kdev, "unable to find MDIO bus node\n");