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 72A07C6FD18 for ; Thu, 30 Mar 2023 02:26:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229573AbjC3C0J (ORCPT ); Wed, 29 Mar 2023 22:26:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229448AbjC3C0I (ORCPT ); Wed, 29 Mar 2023 22:26:08 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EDBA64C2D for ; Wed, 29 Mar 2023 19:26:06 -0700 (PDT) Received: from kwepemm600013.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4Pn6dc6crXz17Q8s; Thu, 30 Mar 2023 10:22:44 +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 10:26:00 +0800 Subject: Re: [PATCH] ubifs: Free memory for tmpfile name To: =?UTF-8?Q?M=c3=a5rten_Lindahl?= , Richard Weinberger CC: , , References: <20230329-memleak-fix-v1-1-7133da56ea8f@axis.com> From: Zhihao Cheng Message-ID: Date: Thu, 30 Mar 2023 10:25:59 +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: <20230329-memleak-fix-v1-1-7133da56ea8f@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, > 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. 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()? > > --- > base-commit: c9c3395d5e3dcc6daee66c6908354d47bf98cb0c > change-id: 20230329-memleak-fix-87a01daf469e > > Best regards, >