From patchwork Wed Oct 11 03:24:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinjie Ruan X-Patchwork-Id: 13416531 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A236663B5 for ; Wed, 11 Oct 2023 03:24:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E22D192 for ; Tue, 10 Oct 2023 20:24:56 -0700 (PDT) Received: from kwepemi500008.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4S4yhn3LBKzkY9G; Wed, 11 Oct 2023 11:20:57 +0800 (CST) Received: from huawei.com (10.90.53.73) by kwepemi500008.china.huawei.com (7.221.188.139) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 11 Oct 2023 11:24:54 +0800 From: Jinjie Ruan To: , Florian Fainelli , Andrew Lunn , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Vivien Didelot CC: Subject: [PATCH v3] net: dsa: bcm_sf2: Fix possible memory leak in bcm_sf2_mdio_register() Date: Wed, 11 Oct 2023 11:24:19 +0800 Message-ID: <20231011032419.2423290-1-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemi500008.china.huawei.com (7.221.188.139) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org 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 Suggested-by: Simon Horman Reviewed-by: Simon Horman Reviewed-by: Florian Fainelli --- v3: - Unwind from errors for bcm_sf2_mdio_register(). - Update the commit message. - Add Suggested-by. v2: - Update the commit message. --- drivers/net/dsa/bcm_sf2.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) 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); }