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

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

[Joe Hattori]

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.

Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
---
 drivers/net/dsa/bcm_sf2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/bcm_sf2.c b/drivers/net/dsa/bcm_sf2.c
index ed1e6560df25..0e663ec0c12a 100644
--- a/drivers/net/dsa/bcm_sf2.c
+++ b/drivers/net/dsa/bcm_sf2.c
@@ -675,8 +675,10 @@ 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->user_mii_bus);
-- 
2.34.1

Re: [PATCH] net: dsa: bcm_sf2: Fix a possible memory leak in bcm_sf2_mdio_register()

[Jakub Kicinski]

On Fri,  2 Aug 2024 17:54:11 +0900 Joe Hattori wrote:
> 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.

Please add a Fixes tag pointing to the commit where the problem was
introduced and make sure you CC the maintainer of the driver.
-- 
pw-bot: cr