From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16377C4332F for ; Mon, 21 Nov 2022 09:01:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229834AbiKUJBu (ORCPT ); Mon, 21 Nov 2022 04:01:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229897AbiKUJBt (ORCPT ); Mon, 21 Nov 2022 04:01:49 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78C7B2D1F5 for ; Mon, 21 Nov 2022 01:01:47 -0800 (PST) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NG1Zs5JcJzHvld; Mon, 21 Nov 2022 17:01:09 +0800 (CST) Received: from dggpemm500007.china.huawei.com (7.185.36.183) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 21 Nov 2022 17:01:44 +0800 Received: from [10.174.178.174] (10.174.178.174) by dggpemm500007.china.huawei.com (7.185.36.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 21 Nov 2022 17:01:43 +0800 Subject: Re: [PATCH v2] usb: roles: fix of node refcount leak in usb_role_switch_is_parent() To: Heikki Krogerus , =?UTF-8?B?Q2h1bmZlbmcgWXVuICjkupHmmKXls7Ap?= CC: "gregkh@linuxfoundation.org" , "linux-usb@vger.kernel.org" , References: <20221119091541.1755640-1-yangyingliang@huawei.com> <097dc06a02377bf67e4d67a016060dbcd06f4798.camel@mediatek.com> From: Yang Yingliang Message-ID: <3dbcee61-7163-d210-5862-90495d049b90@huawei.com> Date: Mon, 21 Nov 2022 17:01:43 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [10.174.178.174] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500007.china.huawei.com (7.185.36.183) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hi, On 2022/11/21 16:55, Heikki Krogerus wrote: > Hi, > > On Mon, Nov 21, 2022 at 07:49:31AM +0000, Chunfeng Yun (云春峰) wrote: >> On Sat, 2022-11-19 at 17:15 +0800, Yang Yingliang wrote: >>> I got the following report while doing device(mt6370-tcpc) load >>> test with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled: >>> >>> OF: ERROR: memory leak, expected refcount 1 instead of 2, >>> of_node_get()/of_node_put() unbalanced - destroy cset entry: >>> attach overlay node /i2c/pmic@34 >>> >>> The 'parent' returned by fwnode_get_parent() with refcount >>> incremented. >>> it needs be put after using. >>> >>> Fixes: 6fadd72943b8 ("usb: roles: get usb-role-switch from parent") >>> Signed-off-by: Yang Yingliang >>> --- >>> v1 -> v2: >>> Add description to how is the report generated. >>> --- >>> drivers/usb/roles/class.c | 6 +++++- >>> 1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c >>> index dfaed7eee94f..289950e5fcfb 100644 >>> --- a/drivers/usb/roles/class.c >>> +++ b/drivers/usb/roles/class.c >>> @@ -106,10 +106,14 @@ usb_role_switch_is_parent(struct fwnode_handle >>> *fwnode) >>> struct fwnode_handle *parent = fwnode_get_parent(fwnode); >>> struct device *dev; >>> >>> - if (!parent || !fwnode_property_present(parent, "usb-role- >>> switch")) >>> + if (!parent || !fwnode_property_present(parent, "usb-role- >>> switch")) { >>> + if (parent) >>> + fwnode_handle_put(parent); >>> return NULL; >>> + } > fwnode API should be NULL safe, so perhaps like this - clean also the > old condition while at it: > > if (!fwnode_property_present(parent, "usb-role-switch")) { > fwnode_handle_put(parent); > return NULL; > } Thanks for your suggestion, I will send a v3 to change this. Thanks, Yang > >>> dev = class_find_device_by_fwnode(role_class, parent); >>> + fwnode_handle_put(parent); >>> return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER); >>> } >>> >> + Heikki > Thanks Chunfeng! > > cheers, >