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 40E7FC4332F for ; Tue, 18 Oct 2022 13:39:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230458AbiJRNjs (ORCPT ); Tue, 18 Oct 2022 09:39:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229896AbiJRNjn (ORCPT ); Tue, 18 Oct 2022 09:39:43 -0400 Received: from out30-42.freemail.mail.aliyun.com (out30-42.freemail.mail.aliyun.com [115.124.30.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BDCA17E36 for ; Tue, 18 Oct 2022 06:39:42 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=joseph.qi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VSWMbx8_1666100376; Received: from 30.39.171.32(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0VSWMbx8_1666100376) by smtp.aliyun-inc.com; Tue, 18 Oct 2022 21:39:38 +0800 Message-ID: Date: Tue, 18 Oct 2022 21:39:36 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.3.3 Subject: Re: [PATCH] ocfs2: possible memory leak in mlog_sys_init() Content-Language: en-US To: Yang Yingliang , linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com Cc: mark@fasheh.com, jlbec@evilplan.org, gregkh@linuxfoundation.org, akpm@linux-foundation.org References: <20221018075213.736562-1-yangyingliang@huawei.com> <09bb2844-e20a-98e8-c2af-5b6c4795d48e@huawei.com> From: Joseph Qi In-Reply-To: <09bb2844-e20a-98e8-c2af-5b6c4795d48e@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/18/22 6:33 PM, Yang Yingliang wrote: > 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. > Yes, you are right. I've mixed the two ksets up. In theory, kset_register() may return error because of a NULL kset, so here we may not call kset_put() directly, I'm not sure if a static checker will happy. Though this can't happen since it's already statically allocated... Thanks, Joseph