6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jinjie Ruan ruanjinjie@huawei.com
commit 61b40cefe51af005c72dbdcf975a3d166c6e6406 upstream.
In bcm_sf2_mdio_register(), the class_find_device() will call get_device() to increment reference count for priv->master_mii_bus->dev if of_mdio_find_bus() succeeds. If mdiobus_alloc() or mdiobus_register() fails, it will call get_device() twice without decrement reference count for the device. And it is the same if bcm_sf2_mdio_register() succeeds but fails in bcm_sf2_sw_probe(), or if bcm_sf2_sw_probe() succeeds. If the reference count has not decremented to zero, the dev related resource will not be freed.
So remove the get_device() in bcm_sf2_mdio_register(), and call put_device() if mdiobus_alloc() or mdiobus_register() fails and in bcm_sf2_mdio_unregister() to solve the issue.
And as Simon suggested, unwind from errors for bcm_sf2_mdio_register() and just return 0 if it succeeds to make it cleaner.
Fixes: 461cd1b03e32 ("net: dsa: bcm_sf2: Register our slave MDIO bus") Signed-off-by: Jinjie Ruan ruanjinjie@huawei.com Suggested-by: Simon Horman horms@kernel.org Reviewed-by: Simon Horman horms@kernel.org Reviewed-by: Florian Fainelli florian.fainelli@broadcom.com Link: https://lore.kernel.org/r/20231011032419.2423290-1-ruanjinjie@huawei.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/dsa/bcm_sf2.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-)
--- a/drivers/net/dsa/bcm_sf2.c +++ b/drivers/net/dsa/bcm_sf2.c @@ -617,17 +617,16 @@ static int bcm_sf2_mdio_register(struct dn = of_find_compatible_node(NULL, NULL, "brcm,unimac-mdio"); priv->master_mii_bus = of_mdio_find_bus(dn); if (!priv->master_mii_bus) { - of_node_put(dn); - return -EPROBE_DEFER; + err = -EPROBE_DEFER; + goto err_of_node_put; }
- get_device(&priv->master_mii_bus->dev); priv->master_mii_dn = dn;
priv->slave_mii_bus = mdiobus_alloc(); if (!priv->slave_mii_bus) { - of_node_put(dn); - return -ENOMEM; + err = -ENOMEM; + goto err_put_master_mii_bus_dev; }
priv->slave_mii_bus->priv = priv; @@ -684,11 +683,17 @@ static int bcm_sf2_mdio_register(struct }
err = mdiobus_register(priv->slave_mii_bus); - if (err && dn) { - mdiobus_free(priv->slave_mii_bus); - of_node_put(dn); - } + if (err && dn) + goto err_free_slave_mii_bus; + + return 0;
+err_free_slave_mii_bus: + mdiobus_free(priv->slave_mii_bus); +err_put_master_mii_bus_dev: + put_device(&priv->master_mii_bus->dev); +err_of_node_put: + of_node_put(dn); return err; }
@@ -696,6 +701,7 @@ static void bcm_sf2_mdio_unregister(stru { mdiobus_unregister(priv->slave_mii_bus); mdiobus_free(priv->slave_mii_bus); + put_device(&priv->master_mii_bus->dev); of_node_put(priv->master_mii_dn); }