Commit cb376176 authored by Zeng Heng's avatar Zeng Heng Committed by Paolo Abeni
Browse files

net: mdio: fix unbalanced fwnode reference count in mdio_device_release() 



There is warning report about of_node refcount leak
while probing mdio device:

OF: ERROR: memory leak, expected refcount 1 instead of 2,
of_node_get()/of_node_put() unbalanced - destroy cset entry:
attach overlay node /spi/soc@0/mdio@710700c0/ethernet@4

In of_mdiobus_register_device(), we increase fwnode refcount
by fwnode_handle_get() before associating the of_node with
mdio device, but it has never been decreased in normal path.
Since that, in mdio_device_release(), it needs to call
fwnode_handle_put() in addition instead of calling kfree()
directly.

After above, just calling mdio_device_free() in the error handle
path of of_mdiobus_register_device() is enough to keep the
refcount balanced.

Fixes: a9049e0c ("mdio: Add support for mdio drivers.")
Signed-off-by: default avatarZeng Heng <zengheng4@huawei.com>
Reviewed-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20221203073441.3885317-1-zengheng4@huawei.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 46401770

drivers/net/mdio/of_mdio.c

+2 −1
Original line number Diff line number Diff line
@@ -68,8 +68,9 @@ static int of_mdiobus_register_device(struct mii_bus *mdio, 
	/* All data is now stored in the mdiodev struct; register it. */

	rc = mdio_device_register(mdiodev);

	if (rc) {

		device_set_node(&mdiodev->dev, NULL);

		fwnode_handle_put(fwnode);

		mdio_device_free(mdiodev);

		of_node_put(child);

		return rc;

	}

drivers/net/phy/mdio_device.c

+2 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/slab.h>

#include <linux/string.h>

#include <linux/unistd.h>

#include <linux/property.h>



void mdio_device_free(struct mdio_device *mdiodev)

{
@@ -30,6 +31,7 @@ EXPORT_SYMBOL(mdio_device_free); 


static void mdio_device_release(struct device *dev)

{

	fwnode_handle_put(dev->fwnode);

	kfree(to_mdio_device(dev));

}