net: mdio: of: fix potential NULL pointer derefernce

of_find_mii_timestamper() returns NULL if no timestamper is found.
Therefore, guard the unregister_mii_timestamper() calls.

Fixes: 1dca22b18421 ("net: mdio: of: Register discovered MII time stampers.")
Signed-off-by: Michael Walle <michael@walle.cc>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index f5c2a548776107c1ef49bc0b7b117dc308ae9002..db0ed5879803f4c50b748a413905464c8db00ca6 100644 (file)
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -81,13 +81,15 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio,
        else
                phy = get_phy_device(mdio, addr, is_c45);
        if (IS_ERR(phy)) {
-               unregister_mii_timestamper(mii_ts);
+               if (mii_ts)
+                       unregister_mii_timestamper(mii_ts);
                return PTR_ERR(phy);
        }
 
        rc = of_irq_get(child, 0);
        if (rc == -EPROBE_DEFER) {
-               unregister_mii_timestamper(mii_ts);
+               if (mii_ts)
+                       unregister_mii_timestamper(mii_ts);
                phy_device_free(phy);
                return rc;
        }
@@ -116,7 +118,8 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio,
         * register it */
        rc = phy_device_register(phy);
        if (rc) {
-               unregister_mii_timestamper(mii_ts);
+               if (mii_ts)
+                       unregister_mii_timestamper(mii_ts);
                phy_device_free(phy);
                of_node_put(child);
                return rc;