netdev - [PATCH net v3] net: mdiobus: fix double put fwnode in the error path

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Message-ID: <20221202051833.699945-1-yangyingliang@huawei.com>
Date:   Fri, 2 Dec 2022 13:18:33 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     <netdev@...r.kernel.org>
CC:     <andrew@...n.ch>, <hkallweit1@...il.com>, <linux@...linux.org.uk>,
        <davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
        <pabeni@...hat.com>, <ioana.ciornei@....com>,
        <calvin.johnson@....nxp.com>, <grant.likely@....com>,
        <zengheng4@...wei.com>
Subject: [PATCH net v3] net: mdiobus: fix double put fwnode in the error path

If phy_device_register() or fwnode_mdiobus_phy_device_register()
fail, phy_device_free() is called, the device refcount is decreased
to 0, then fwnode_handle_put() will be called in phy_device_release(),
but in the error path, fwnode_handle_put() has already been called,
so set fwnode to NULL after fwnode_handle_put() in the error path to
avoid double put.

Fixes: cdde1560118f ("net: mdiobus: fix unbalanced node reference count")
Reported-by: Zeng Heng <zengheng4@...wei.com>
Tested-by: Zeng Heng <zengheng4@...wei.com>
Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
---
v2 -> v3:
  set fwnode to NULL before calling fwnode_handle_put()

v1 -> v2:
  Don't remove fwnode_handle_put() in the error path,
  set fwnode to NULL avoid double put.
---
 drivers/net/mdio/fwnode_mdio.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mdio/fwnode_mdio.c b/drivers/net/mdio/fwnode_mdio.c
index eb344f6d4a7b..b782c35c4ac1 100644
--- a/drivers/net/mdio/fwnode_mdio.c
+++ b/drivers/net/mdio/fwnode_mdio.c
@@ -98,6 +98,7 @@ int fwnode_mdiobus_phy_device_register(struct mii_bus *mdio,
 	 */
 	rc = phy_device_register(phy);
 	if (rc) {
+		device_set_node(&phy->mdio.dev, NULL);
 		fwnode_handle_put(child);
 		return rc;
 	}
@@ -153,7 +154,8 @@ int fwnode_mdiobus_register_phy(struct mii_bus *bus,
 		/* All data is now stored in the phy struct, so register it */
 		rc = phy_device_register(phy);
 		if (rc) {
-			fwnode_handle_put(phy->mdio.dev.fwnode);
+			phy->mdio.dev.fwnode = NULL;
+			fwnode_handle_put(child);
 			goto clean_phy;
 		}
 	} else if (is_of_node(child)) {
-- 
2.25.1