On Tue, 3 Feb 2026, Greg Kroah-Hartman wrote:

On Fri, Jan 16, 2026 at 11:14:45AM +0100, David Nyström wrote:

quoted

[ Upstream commit cb37617687f2bfa5b675df7779f869147c9002bd ]

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.

(cherry picked from commit cb37617687f2bfa5b675df7779f869147c9002bd)

Fixes: a9049e0c513c ("mdio: Add support for mdio drivers.")
Signed-off-by: Zeng Heng <redacted>
Reviewed-by: Yang Yingliang <redacted>
Reviewed-by: Russell King (Oracle) <redacted>
Link: https://lore.kernel.org/r/20221203073441.3885317-1-zengheng4@huawei.com (local)
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David Nyström <redacted>
---
This series backports 1 commit(s) to the 5.10 stable tree.
---
 drivers/net/mdio/of_mdio.c    | 3 ++-
 drivers/net/phy/mdio_device.c | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mdio/of_mdio.c b/drivers/net/mdio/of_mdio.c
index b254127cea50..355c3ee21cd7 100644
--- a/drivers/net/mdio/of_mdio.c
+++ b/drivers/net/mdio/of_mdio.c

@@ -168,8 +168,9 @@ 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;
 	}

diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index 797c41f5590e..f72d18ee2792 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c

@@ -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));
 }

---
base-commit: f964b940099f9982d723d4c77988d4b0dda9c165
change-id: 20260115-backport_cb37617687f2_20260115100804-bb6cefe39d44

Best regards,
--
David Nyström [off-list ref]

Breaks the build, how did you test this:
drivers/net/mdio/of_mdio.c: In function ‘of_mdiobus_register_device’:
drivers/net/mdio/of_mdio.c:172:35: error: ‘fwnode’ undeclared (first use in this function); did you mean ‘inode’?
 172 |                 fwnode_handle_put(fwnode);
     |                                   ^~~~~~
     |                                   inode

Oops,
This patch was work-in-progress and should not have been sent your way.
Wont happen again.

Br,
David