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 E0D93C6FA82 for ; Wed, 21 Sep 2022 01:28:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229791AbiIUB2A (ORCPT ); Tue, 20 Sep 2022 21:28:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231509AbiIUB1R (ORCPT ); Tue, 20 Sep 2022 21:27:17 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50F3F7B78B; Tue, 20 Sep 2022 18:26:27 -0700 (PDT) Received: from canpemm500010.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MXLJs32cmzpSw1; Wed, 21 Sep 2022 09:23:25 +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; Wed, 21 Sep 2022 09:26:13 +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> <6329126D.8060704@huawei.com> CC: , From: yebin Message-ID: <632A6835.9080705@huawei.com> Date: Wed, 21 Sep 2022 09:26:13 +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: 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-kernel@vger.kernel.org On 2022/9/21 2:25, Damien Guibouret wrote: > Hello, > > Le 20/09/2022 à 03:07, yebin a écrit : >> >> >> 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. > > There are at least two calls in ext4_ext_clear_bb (ext4/extents.c) > that do not check for return code of ext4_fc_record_regions. But > perhaps these are these calls that should be fixed. > Thanks very much, Indeed, it's better to repair it here. >>>> return -ENOMEM; >>>> + state->fc_regions = fc_regions; >>>> } >>>> region = &state->fc_regions[state->fc_regions_used++]; >>>> region->ino = ino; >>> > > Regards, > > Damien > > > . >