net: dsa: bcm_sf2: Fix a possible memory leak in bcm_sf2_mdio_register()

BugLink: https://bugs.launchpad.net/bugs/2078428

[ Upstream commit e386209 ]

bcm_sf2_mdio_register() calls of_phy_find_device() and then
phy_device_remove() in a loop to remove existing PHY devices.
of_phy_find_device() eventually calls bus_find_device(), which calls
get_device() on the returned struct device * to increment the refcount.
The current implementation does not decrement the refcount, which causes
memory leak.

This commit adds the missing phy_device_free() call to decrement the
refcount via put_device() to balance the refcount.

Fixes: 771089c ("net: dsa: bcm_sf2: Ensure that MDIO diversion is used")
Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20240806011327.3817861-1-joe@pf.is.s.u-tokyo.ac.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

Author: joehattori

drivers/net/dsa/bcm_sf2.c

@@ -638,8 +638,10 @@ static int bcm_sf2_mdio_register(struct dsa_switch *ds)
 			of_remove_property(child, prop);
 
 		phydev = of_phy_find_device(child);
-		if (phydev)
+		if (phydev) {
 			phy_device_remove(phydev);
+			phy_device_free(phydev);
+		}
 	}
 
 	err = mdiobus_register(priv->slave_mii_bus);