dpaa2-switch: 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() 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@vger.kernel.org
Fixes: 84cba72956fd ("dpaa2-switch: integrate the MAC endpoint support")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250717022309.3339976-3-make24@iscas.ac.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
index 147a93bf9fa913f663676f30559202de9e889f40..4643a33806182050ce9b295529a67d6a33f11bee 100644 (file)
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
@@ -1448,12 +1448,19 @@ 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) {
+               err = 0;
+               goto out_put_device;
+       }
+
        mac = kzalloc(sizeof(*mac), GFP_KERNEL);
-       if (!mac)
-               return -ENOMEM;
+       if (!mac) {
+               err = -ENOMEM;
+               goto out_put_device;
+       }
 
        mac->mc_dev = dpmac_dev;
        mac->mc_io = port_priv->ethsw_data->mc_io;
@@ -1483,6 +1490,8 @@ err_close_mac:
        dpaa2_mac_close(mac);
 err_free_mac:
        kfree(mac);
+out_put_device:
+       put_device(&dpmac_dev->dev);
        return err;
 }