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 5D8BFC6FA82 for ; Tue, 20 Sep 2022 01:08:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229602AbiITBIE (ORCPT ); Mon, 19 Sep 2022 21:08:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229473AbiITBID (ORCPT ); Mon, 19 Sep 2022 21:08:03 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EBC84DB35; Mon, 19 Sep 2022 18:08:01 -0700 (PDT) Received: from canpemm500010.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MWjw60G9CzMn3p; Tue, 20 Sep 2022 09:03:18 +0800 (CST) Received: from [10.174.178.185] (10.174.178.185) by canpemm500010.china.huawei.com (7.192.105.118) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 20 Sep 2022 09:07:58 +0800 Subject: Re: [PATCH -next 1/2] ext4: fix potential memory leak in ext4_fc_record_regions() To: Damien Guibouret , , , References: <20220919144021.2162295-1-yebin10@huawei.com> <20220919144021.2162295-2-yebin10@huawei.com> <02fc228b-7cc5-b470-9b5c-8ad726b18158@partition-saving.com> CC: , From: yebin Message-ID: <6329126D.8060704@huawei.com> Date: Tue, 20 Sep 2022 09:07:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <02fc228b-7cc5-b470-9b5c-8ad726b18158@partition-saving.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.178.185] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500010.china.huawei.com (7.192.105.118) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 2022/9/20 2:40, Damien Guibouret wrote: > Hello, > > Le 19/09/2022 à 16:40, Ye Bin a écrit : >> As krealloc may return NULL, in this case 'state->fc_regions' may not be >> freed by krealloc, but 'state->fc_regions' already set NULL. Then will >> lead to 'state->fc_regions' memory leak. >> >> Signed-off-by: Ye Bin >> --- >> fs/ext4/fast_commit.c | 14 ++++++++------ >> 1 file changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c >> index 9217a588afd1..cc8c8db075ba 100644 >> --- a/fs/ext4/fast_commit.c >> +++ b/fs/ext4/fast_commit.c >> @@ -1677,15 +1677,17 @@ int ext4_fc_record_regions(struct super_block >> *sb, int ino, >> if (replay && state->fc_regions_used != state->fc_regions_valid) >> state->fc_regions_used = state->fc_regions_valid; >> if (state->fc_regions_used == state->fc_regions_size) { >> + struct ext4_fc_alloc_region *fc_regions; >> + >> state->fc_regions_size += >> EXT4_FC_REPLAY_REALLOC_INCREMENT; >> - state->fc_regions = krealloc( >> - state->fc_regions, >> - state->fc_regions_size * >> - sizeof(struct ext4_fc_alloc_region), >> - GFP_KERNEL); >> - if (!state->fc_regions) >> + fc_regions = krealloc(state->fc_regions, >> + state->fc_regions_size * >> + sizeof(struct ext4_fc_alloc_region), >> + GFP_KERNEL); >> + if (!fc_regions) > > Would it not be safer to restore state->fc_regions_size to its > previous value in that case to keep consistency between size value and > allocated size (or to update state->fc_regions_size only after > allocation as it is done in second part of this patch) ? > Actually, If 'ext4_fc_record_regions()' return -ENOMEM, then will stop replay journal. 'state->fc_regions_size' will not be used any more, so it's safe. >> return -ENOMEM; >> + state->fc_regions = fc_regions; >> } >> region = &state->fc_regions[state->fc_regions_used++]; >> region->ino = ino; > > Regards, > > Damien > > . >