net: phy: mdio-mux: Check return value of mdiobus_alloc()

commit 20b08e1a793d898f0f13040d5418ee0955f678cf upstream.

mdiobus_alloc() might return NULL, but its return value is not
checked in mdio_mux_init(). This could potentially lead to a NULL
pointer dereference. Fix it by checking the return value

Fixes: 0ca2997d1452 ("netdev/of/phy: Add MDIO bus multiplexer support.")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
index 4d4d25efc1e10a2b87e3c8ab993ae3ba6167a7dd..ac8a82371f3b7bed1e9a4b6023ccdd9fe2e5863e 100644 (file)
--- a/drivers/net/phy/mdio-mux.c
+++ b/drivers/net/phy/mdio-mux.c
@@ -148,9 +148,14 @@ int mdio_mux_init(struct device *dev,
                }
                cb->bus_number = v;
                cb->parent = pb;
+
                cb->mii_bus = mdiobus_alloc();
+               if (!cb->mii_bus) {
+                       ret_val = -ENOMEM;
+                       of_node_put(child_bus_node);
+                       break;
+               }
                cb->mii_bus->priv = cb;
-
                cb->mii_bus->irq = cb->phy_irq;
                cb->mii_bus->name = "mdio_mux";
                snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",