netdev - [PATCH] net: dpaa2: Fix device reference count leak in MAC endpoint handling

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Message-Id: <20250715120056.3274056-1-make24@iscas.ac.cn>
Date: Tue, 15 Jul 2025 20:00:56 +0800
From: Ma Ke <make24@...as.ac.cn>
To: ioana.ciornei@....com,
	andrew+netdev@...n.ch,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com
Cc: netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org,
	Ma Ke <make24@...as.ac.cn>,
	stable@...r.kernel.org
Subject: [PATCH] net: dpaa2: Fix device reference count leak in MAC endpoint handling

The fsl_mc_get_endpoint() function uses device_find_child() for
localization, which implicitly calls get_device() to increment the
device's reference count before returning the pointer. However, the
caller dpaa2_switch_port_connect_mac() and dpaa2_eth_connect_mac()
fails to properly release this reference in multiple scenarios. We
should call put_device() to decrement reference count properly.

As comment of device_find_child() says, 'NOTE: you will need to drop
the reference with put_device() after use'.

Found by code review.

Cc: stable@...r.kernel.org
Fixes: 719479230893 ("dpaa2-eth: add MAC/PHY support through phylink")
Fixes: 84cba72956fd ("dpaa2-switch: integrate the MAC endpoint support")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
 drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 15 ++++++++++++---
 .../net/ethernet/freescale/dpaa2/dpaa2-switch.c  | 15 ++++++++++++---
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index b82f121cadad..f1543039a5b6 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -4666,12 +4666,19 @@ static int dpaa2_eth_connect_mac(struct dpaa2_eth_priv *priv)
 		return PTR_ERR(dpmac_dev);
 	}
 
-	if (IS_ERR(dpmac_dev) || dpmac_dev->dev.type != &fsl_mc_bus_dpmac_type)
+	if (IS_ERR(dpmac_dev))
 		return 0;
 
+	if (dpmac_dev->dev.type != &fsl_mc_bus_dpmac_type) {
+		put_device(&dpmac_dev->dev);
+		return 0;
+	}
+
 	mac = kzalloc(sizeof(struct dpaa2_mac), GFP_KERNEL);
-	if (!mac)
+	if (!mac) {
+		put_device(&dpmac_dev->dev);
 		return -ENOMEM;
+	}
 
 	mac->mc_dev = dpmac_dev;
 	mac->mc_io = priv->mc_io;
@@ -4679,7 +4686,7 @@ static int dpaa2_eth_connect_mac(struct dpaa2_eth_priv *priv)
 
 	err = dpaa2_mac_open(mac);
 	if (err)
-		goto err_free_mac;
+		goto err_put_device;
 
 	if (dpaa2_mac_is_type_phy(mac)) {
 		err = dpaa2_mac_connect(mac);
@@ -4703,6 +4710,8 @@ static int dpaa2_eth_connect_mac(struct dpaa2_eth_priv *priv)
 
 err_close_mac:
 	dpaa2_mac_close(mac);
+err_put_device:
+	put_device(&dpmac_dev->dev);
 err_free_mac:
 	kfree(mac);
 	return err;
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
index 147a93bf9fa9..6bf1c164129a 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
@@ -1448,12 +1448,20 @@ static int dpaa2_switch_port_connect_mac(struct ethsw_port_priv *port_priv)
 	if (PTR_ERR(dpmac_dev) == -EPROBE_DEFER)
 		return PTR_ERR(dpmac_dev);
 
-	if (IS_ERR(dpmac_dev) || dpmac_dev->dev.type != &fsl_mc_bus_dpmac_type)
+	if (IS_ERR(dpmac_dev))
 		return 0;
+
+	if (dpmac_dev->dev.type != &fsl_mc_bus_dpmac_type) {
+		put_device(&dpmac_dev->dev);
+		return 0;
+	}
 
 	mac = kzalloc(sizeof(*mac), GFP_KERNEL);
-	if (!mac)
+	if (!mac) {
+		put_device(&dpmac_dev->dev);
 		return -ENOMEM;
+	}
 
 	mac->mc_dev = dpmac_dev;
 	mac->mc_io = port_priv->ethsw_data->mc_io;
@@ -1461,7 +1469,7 @@ static int dpaa2_switch_port_connect_mac(struct ethsw_port_priv *port_priv)
 
 	err = dpaa2_mac_open(mac);
 	if (err)
-		goto err_free_mac;
+		goto err_put_device;
 
 	if (dpaa2_mac_is_type_phy(mac)) {
 		err = dpaa2_mac_connect(mac);
@@ -1481,6 +1489,8 @@ static int dpaa2_switch_port_connect_mac(struct ethsw_port_priv *port_priv)
 
 err_close_mac:
 	dpaa2_mac_close(mac);
+err_put_device:
+	put_device(&dpmac_dev->dev);
 err_free_mac:
 	kfree(mac);
 	return err;
-- 
2.25.1