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 85116C6FD1D for ; Thu, 30 Mar 2023 08:22:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230325AbjC3IWy (ORCPT ); Thu, 30 Mar 2023 04:22:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230304AbjC3IWZ (ORCPT ); Thu, 30 Mar 2023 04:22:25 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F0857DB2 for ; Thu, 30 Mar 2023 01:21:54 -0700 (PDT) Received: from kwepemm600013.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4PnGXh0Kf7zKx6m; Thu, 30 Mar 2023 16:19:00 +0800 (CST) Received: from [10.174.178.46] (10.174.178.46) by kwepemm600013.china.huawei.com (7.193.23.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Thu, 30 Mar 2023 16:21:23 +0800 Subject: Re: [PATCH] ubifs: Free memory for tmpfile name To: =?UTF-8?Q?M=c3=a5rten_Lindahl?= , =?UTF-8?Q?M=c3=a5rten_Lindahl?= , Richard Weinberger CC: , , References: <20230329-memleak-fix-v1-1-7133da56ea8f@axis.com> <61344864-cfc1-0c57-bf3b-38e5a125d281@axis.com> From: Zhihao Cheng Message-ID: <6f00b571-bb94-e50b-9b9c-e08c7dcc0d50@huawei.com> Date: Thu, 30 Mar 2023 16:21:22 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <61344864-cfc1-0c57-bf3b-38e5a125d281@axis.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.178.46] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemm600013.china.huawei.com (7.193.23.68) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mårten, > Hi Zhihao! > > On 3/30/23 04:25, Zhihao Cheng wrote: >> Hi Mårten, >>> When opening a ubifs tmpfile on an encrypted directory, function >>> fscrypt_setup_filename allocates memory for the name that is to be >>> stored in the directory entry, but after the name has been copied to the >>> directory entry inode, the memory is not freed. >>> >>> When running kmemleak on it we see that it is registered as a leak. The >>> report below is triggered by a simple program 'tmpfile' just opening a >>> tmpfile: >>> >>>    unreferenced object 0xffff88810178f380 (size 32): >>>      comm "tmpfile", pid 509, jiffies 4294934744 (age 1524.742s) >>>      backtrace: >>>        __kmem_cache_alloc_node >>>        __kmalloc >>>        fscrypt_setup_filename >>>        ubifs_tmpfile >>>        vfs_tmpfile >>>        path_openat >>> >>> Free this memory after it has been copied to the inode. >>> >>> Signed-off-by: Mårten Lindahl >>> --- >>>   fs/ubifs/dir.c | 1 + >>>   1 file changed, 1 insertion(+) >>> >>> diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c >>> index 0f29cf201136..089ca6910124 100644 >>> --- a/fs/ubifs/dir.c >>> +++ b/fs/ubifs/dir.c >>> @@ -491,6 +491,7 @@ static int ubifs_tmpfile(struct user_namespace >>> *mnt_userns, struct inode *dir, >>>           goto out_cancel; >>>       unlock_2_inodes(dir, inode); >>>   +    fscrypt_free_filename(&nm); >>>       ubifs_release_budget(c, &req); >>>         return finish_open_simple(file, 0); >> >> Looks good, just one small nit. I'd prefer to add >> fscrypt_free_filename() after ubifs_release_budget() just like >> ubifs_create/link does, so that ubifs can get unused budget earlier. > OK, I will move it after ubifs_release_budget. >> >> After looking through the code, I found another place create_whiteout >> has the same problem(Imported in 278d9a243635f26c05("ubifs: Rename >> whiteout atomically") by me). Would you mind fixing this point just by >> removing unused 'nm' in create_whiteout()? > > I see what you mean. As I understand it calling fscrypt_setup_filename > is not needed in create_whiteout. I would prefer removing those lines in > a separate patch since that leak is related to do_rename(). If it's OK > with you I can make a patch for that. Would that be OK? > Yes. You may send another patch to fix it. Thanks.