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 2FEE2C43217 for ; Tue, 18 Oct 2022 10:33:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229890AbiJRKdp (ORCPT ); Tue, 18 Oct 2022 06:33:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229981AbiJRKdd (ORCPT ); Tue, 18 Oct 2022 06:33:33 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FAFEB40CD for ; Tue, 18 Oct 2022 03:33:31 -0700 (PDT) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Ms97p3ztxzVhsb; Tue, 18 Oct 2022 18:28:54 +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; Tue, 18 Oct 2022 18:33:30 +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; Tue, 18 Oct 2022 18:33:29 +0800 Subject: Re: [PATCH] ocfs2: possible memory leak in mlog_sys_init() To: Joseph Qi , , CC: , , , References: <20221018075213.736562-1-yangyingliang@huawei.com> From: Yang Yingliang Message-ID: <09bb2844-e20a-98e8-c2af-5b6c4795d48e@huawei.com> Date: Tue, 18 Oct 2022 18:33:29 +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: 7bit 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-kernel@vger.kernel.org Hi, On 2022/10/18 17:02, Joseph Qi wrote: > Hi, > > On 10/18/22 3:52 PM, Yang Yingliang wrote: >> Inject fault while probing module, kset_register() may fail, >> if it fails, but the refcount of kobject is not decreased to >> 0, the name allocated in kobject_set_name() is leaked. Fix >> this by calling kset_put(), so that name can be freed in >> callback function kobject_cleanup(). >> >> unreferenced object 0xffff888100da9348 (size 8): >> comm "modprobe", pid 257, jiffies 4294701096 (age 33.334s) >> hex dump (first 8 bytes): >> 6c 6f 67 6d 61 73 6b 00 logmask. >> backtrace: >> [<00000000306e441c>] __kmalloc_node_track_caller+0x44/0x1b0 >> [<000000007c491a9e>] kstrdup+0x3a/0x70 >> [<0000000015719a3b>] kstrdup_const+0x63/0x80 >> [<0000000084e458ea>] kvasprintf_const+0x149/0x180 >> [<0000000091302b42>] kobject_set_name_vargs+0x56/0x150 >> [<000000005f48eeac>] kobject_set_name+0xab/0xe0 >> >> Fixes: 34980ca8faeb ("Drivers: clean up direct setting of the name of a kset") >> Signed-off-by: Yang Yingliang >> --- >> fs/ocfs2/cluster/masklog.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/fs/ocfs2/cluster/masklog.c b/fs/ocfs2/cluster/masklog.c >> index 563881ddbf00..7f9ba816d955 100644 >> --- a/fs/ocfs2/cluster/masklog.c >> +++ b/fs/ocfs2/cluster/masklog.c >> @@ -156,6 +156,7 @@ static struct kset mlog_kset = { >> int mlog_sys_init(struct kset *o2cb_kset) >> { >> int i = 0; >> + int ret; >> >> while (mlog_attrs[i].attr.mode) { >> mlog_default_attrs[i] = &mlog_attrs[i].attr; >> @@ -165,7 +166,11 @@ int mlog_sys_init(struct kset *o2cb_kset) >> >> kobject_set_name(&mlog_kset.kobj, "logmask"); >> mlog_kset.kobj.kset = o2cb_kset; >> - return kset_register(&mlog_kset); >> + ret = kset_register(&mlog_kset); > If register fails, it will call unregister in o2cb_sys_init(), which > will put kobject. They are different ksets, the kset unregistered in o2cb_sys_init() is 'o2cb_kset', the kset used to registered in mlog_sys_init() is 'mlog_kset', and they hold difference refcounts. Thanks, Yang > > Thanks, > Joseph > >> + if (ret) >> + kset_put(&mlog_kset); >> + >> + return ret; >> } >> >> void mlog_sys_shutdown(void) > .