[PATCH 5.4 222/260] net: dsa: destroy the phylink instance on any error in dsa_slave_phy_setup

From: Greg Kroah-Hartman
Date: Mon Sep 20 2021 - 14:25:17 EST


From: Vladimir Oltean <vladimir.oltean@xxxxxxx>

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: aab9c4067d23 ("net: dsa: Plug in PHYLINK support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Reviewed-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210914134331.2303380-1-vladimir.oltean@xxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/dsa/slave.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1327,13 +1327,11 @@ static int dsa_slave_phy_setup(struct ne
* 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);
- phylink_destroy(dp->pl);
- return ret;
- }
+ }
+ if (ret) {
+ netdev_err(slave_dev, "failed to connect to PHY: %pe\n",
+ ERR_PTR(ret));
+ phylink_destroy(dp->pl);
}

return ret;