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 F1BBAECAAA1 for ; Mon, 19 Sep 2022 18:40:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229693AbiISSkq (ORCPT ); Mon, 19 Sep 2022 14:40:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229663AbiISSko (ORCPT ); Mon, 19 Sep 2022 14:40:44 -0400 Received: from smtp6-g21.free.fr (smtp6-g21.free.fr [IPv6:2a01:e0c:1:1599::15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFE3A3AE75; Mon, 19 Sep 2022 11:40:42 -0700 (PDT) Received: from [192.168.103.121] (unknown [88.163.97.197]) by smtp6-g21.free.fr (Postfix) with ESMTPS id 0166E780371; Mon, 19 Sep 2022 20:40:34 +0200 (CEST) Message-ID: <02fc228b-7cc5-b470-9b5c-8ad726b18158@partition-saving.com> Date: Mon, 19 Sep 2022 20:40:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH -next 1/2] ext4: fix potential memory leak in ext4_fc_record_regions() Content-Language: en-US To: Ye Bin , tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org Cc: linux-kernel@vger.kernel.org, jack@suse.cz References: <20220919144021.2162295-1-yebin10@huawei.com> <20220919144021.2162295-2-yebin10@huawei.com> From: Damien Guibouret In-Reply-To: <20220919144021.2162295-2-yebin10@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org 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) ? > return -ENOMEM; > + state->fc_regions = fc_regions; > } > region = &state->fc_regions[state->fc_regions_used++]; > region->ino = ino; Regards, Damien