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 --- .../net/ethernet/freescale/dpaa2/dpaa2-switch.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c index 147a93bf9fa9..4643a3380618 100644 --- 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 @@ static int dpaa2_switch_port_connect_mac(struct ethsw_port_priv *port_priv) dpaa2_mac_close(mac); err_free_mac: kfree(mac); +out_put_device: + put_device(&dpmac_dev->dev); return err; }

On Thu, Jul 17, 2025 at 10:23:07AM +0800, Ma Ke wrote:

The fsl_mc_get_endpoint() function may call fsl_mc_device_lookup() twice, which would increment the device's reference count twice if both lookups find a device. This could lead to a reference count leak.

Found by code review.

Cc: stable@vger.kernel.org Fixes: 1ac210d128ef ("bus: fsl-mc: add the fsl_mc_get_endpoint function")

I think this should be:

Fixes: 8567494cebe5 ("bus: fsl-mc: rescan devices if endpoint not found")

I've CCed Laurentiu, the author of that commit.

Signed-off-by: Ma Ke make24@iscas.ac.cn

Suggested-by: Simon Horman horms@kernel.org Reviewed-by: Simon Horman horms@kernel.org

---

drivers/bus/fsl-mc/fsl-mc-bus.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index 7671bd158545..c1c0a4759c7e 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -943,6 +943,7 @@ struct fsl_mc_device *fsl_mc_get_endpoint(struct fsl_mc_device *mc_dev, struct fsl_mc_obj_desc endpoint_desc = {{ 0 }}; struct dprc_endpoint endpoint1 = {{ 0 }}; struct dprc_endpoint endpoint2 = {{ 0 }};

• struct fsl_mc_bus *mc_bus; int state, err;

mc_bus_dev = to_fsl_mc_device(mc_dev->dev.parent); @@ -966,6 +967,8 @@ struct fsl_mc_device *fsl_mc_get_endpoint(struct fsl_mc_device *mc_dev, strcpy(endpoint_desc.type, endpoint2.type); endpoint_desc.id = endpoint2.id; endpoint = fsl_mc_device_lookup(&endpoint_desc, mc_bus_dev);

• if (endpoint)

• return endpoint;
  

/* * We know that the device has an endpoint because we verified by @@ -973,17 +976,13 @@ struct fsl_mc_device *fsl_mc_get_endpoint(struct fsl_mc_device *mc_dev, * yet discovered by the fsl-mc bus, thus the lookup returned NULL. * Force a rescan of the devices in this container and retry the lookup. */

• if (!endpoint) {

• struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_bus_dev);
  

• if (mutex_trylock(&mc_bus->scan_mutex)) {
  

• 	err = dprc_scan_objects(mc_bus_dev, true);
  

• 	mutex_unlock(&mc_bus->scan_mutex);
  

• }
  

• if (err < 0)
  

• 	return ERR_PTR(err);
  

• mc_bus = to_fsl_mc_bus(mc_bus_dev);
• if (mutex_trylock(&mc_bus->scan_mutex)) {

• err = dprc_scan_objects(mc_bus_dev, true);
  

• mutex_unlock(&mc_bus->scan_mutex);
  

  }
• if (err < 0)

• return ERR_PTR(err);
  

endpoint = fsl_mc_device_lookup(&endpoint_desc, mc_bus_dev); /* -- 2.25.1