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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70370C04E30 for ; Mon, 9 Dec 2019 18:25:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D2E02077B for ; Mon, 9 Dec 2019 18:25:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726785AbfLISZz (ORCPT ); Mon, 9 Dec 2019 13:25:55 -0500 Received: from mx2.suse.de ([195.135.220.15]:36084 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726642AbfLISZx (ORCPT ); Mon, 9 Dec 2019 13:25:53 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 5212CAD2D; Mon, 9 Dec 2019 18:25:51 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id EA416DA82A; Mon, 9 Dec 2019 19:25:43 +0100 (CET) Date: Mon, 9 Dec 2019 19:25:43 +0100 From: David Sterba To: Dinghao Liu Cc: kjlu@umn.edu, Chris Mason , Josef Bacik , David Sterba , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] btrfs: add missing check after link_free_space Message-ID: <20191209182543.GQ2734@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Dinghao Liu , kjlu@umn.edu, Chris Mason , Josef Bacik , David Sterba , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org References: <20191209034114.16212-1-dinghao.liu@zju.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191209034114.16212-1-dinghao.liu@zju.edu.cn> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon, Dec 09, 2019 at 11:41:14AM +0800, Dinghao Liu wrote: > The return value of link_free_space is checked out-sync. > One branch of an if statement uses an extra check after > WARN_ON() but its peer branch does not. WARN_ON() does > not change the control flow, thus only using this check > might be insufficient. > > Fix this by simply adding a check on ret. > > Signed-off-by: Dinghao Liu > -- > Changes in v2: > - Add memory free for free space entry. > --- > fs/btrfs/free-space-cache.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c > index 3283da419200..ba2e6cea5233 100644 > --- a/fs/btrfs/free-space-cache.c > +++ b/fs/btrfs/free-space-cache.c > @@ -2437,6 +2437,10 @@ int btrfs_remove_free_space(struct btrfs_block_group *block_group, > if (info->bytes) { > ret = link_free_space(ctl, info); > WARN_ON(ret); > + if (ret) { > + kmem_cache_free(btrfs_free_space_cachep, info); > + goto out_lock; > + } > } else { > kmem_cache_free(btrfs_free_space_cachep, info); There are two link_free_space followed by WARN_ON instances in the function, please remove both. In the above case, the branches can be merged together so there's not repeated kmem_cache_free, like if (info->bytes) ret = link_free_space(...); kmem_cache_free(btrfs_free_space_cachep, info); if (ret) goto out_unlock;