The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 61b40cefe51af005c72dbdcf975a3d166c6e6406 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023102039-chance-unseen-916d@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 61b40cefe51af005c72dbdcf975a3d166c6e6406 Mon Sep 17 00:00:00 2001 From: Jinjie Ruan ruanjinjie@huawei.com Date: Wed, 11 Oct 2023 11:24:19 +0800 Subject: [PATCH] net: dsa: bcm_sf2: Fix possible memory leak in bcm_sf2_mdio_register()
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
diff --git a/drivers/net/dsa/bcm_sf2.c b/drivers/net/dsa/bcm_sf2.c index 72374b066f64..cd1f240c90f3 100644 --- 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 dsa_switch *ds) 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 dsa_switch *ds) }
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(struct bcm_sf2_priv *priv) { 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); }