Commit 948fa0ba authored Sep 14, 2021 by Vladimir Oltean Committed by Greg Kroah-Hartman Sep 22, 2021

net: dsa: destroy the phylink instance on any error in dsa_slave_phy_setup



commit 6a52e73368038f47f6618623d75061dc263b26ae upstream.

DSA supports connecting to a phy-handle, and has a fallback to a non-OF
based method of connecting to an internal PHY on the switch's own MDIO
bus, if no phy-handle and no fixed-link nodes were present.

The -ENODEV error code from the first attempt (phylink_of_phy_connect)
is what triggers the second attempt (phylink_connect_phy).

However, when the first attempt returns a different error code than
-ENODEV, this results in an unbalance of calls to phylink_create and
phylink_destroy by the time we exit the function. The phylink instance
has leaked.

There are many other error codes that can be returned by
phylink_of_phy_connect. For example, phylink_validate returns -EINVAL.
So this is a practical issue too.

Fixes: aab9c406 ("net: dsa: Plug in PHYLINK support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20210914134331.2303380-1-vladimir.oltean@nxp.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 44ba2815

net/dsa/slave.c

+5 −7

Original line number	Diff line number	Diff line
		@@ -1226,13 +1226,11 @@ static int dsa_slave_phy_setup(struct net_device *slave_dev)
		* use the switch internal MDIO bus instead
		*/
		ret = dsa_slave_phy_connect(slave_dev, dp->index);
		}
		if (ret) {
		netdev_err(slave_dev,
		"failed to connect to port %d: %d\n",
		dp->index, ret);
		netdev_err(slave_dev, "failed to connect to PHY: %pe\n",
		ERR_PTR(ret));
		phylink_destroy(dp->pl);
		return ret;
		}
		}

		return ret;