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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 65C86C56201 for ; Thu, 26 Nov 2020 01:21:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C432216C4 for ; Thu, 26 Nov 2020 01:21:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731502AbgKZBVS (ORCPT ); Wed, 25 Nov 2020 20:21:18 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:8589 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730762AbgKZBVS (ORCPT ); Wed, 25 Nov 2020 20:21:18 -0500 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4ChKhH5ZwGzLvWM; Thu, 26 Nov 2020 09:20:47 +0800 (CST) Received: from [10.174.177.149] (10.174.177.149) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.487.0; Thu, 26 Nov 2020 09:21:11 +0800 Subject: Re: [PATCH] xfs: check the return value of krealloc() in xfs_uuid_mount To: Eric Sandeen , "Darrick J. Wong" , CC: References: <20201125065036.154312-1-miaoqinglang@huawei.com> <365b952c-7fea-3bc2-55ea-3f6b1c9f9142@sandeen.net> From: Qinglang Miao Message-ID: <9f998a9d-0684-6b45-009e-acf2e0ac4c85@huawei.com> Date: Thu, 26 Nov 2020 09:21:11 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <365b952c-7fea-3bc2-55ea-3f6b1c9f9142@sandeen.net> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.149] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2020/11/25 23:55, Eric Sandeen 写道: > On 11/25/20 12:50 AM, Qinglang Miao wrote: >> krealloc() may fail to expand the memory space. > > Even with __GFP_NOFAIL? > > * ``GFP_KERNEL | __GFP_NOFAIL`` - overrides the default allocator behavior > and all allocation requests will loop endlessly until they succeed. > This might be really dangerous especially for larger orders. > >> Add sanity checks to it, >> and WARN() if that really happened. > > As aside, there is no WARN added in this patch for a memory failure. > >> Fixes: 771915c4f688 ("xfs: remove kmem_realloc()") >> Reported-by: Hulk Robot >> Signed-off-by: Qinglang Miao >> --- >> fs/xfs/xfs_mount.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c >> index 150ee5cb8..c07f48c32 100644 >> --- a/fs/xfs/xfs_mount.c >> +++ b/fs/xfs/xfs_mount.c >> @@ -80,9 +80,13 @@ xfs_uuid_mount( >> } >> >> if (hole < 0) { >> - xfs_uuid_table = krealloc(xfs_uuid_table, >> + uuid_t *if_xfs_uuid_table; >> + if_xfs_uuid_table = krealloc(xfs_uuid_table, >> (xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table), >> GFP_KERNEL | __GFP_NOFAIL); >> + if (!if_xfs_uuid_table) >> + goto out_duplicate; > > And this would emit "Filesystem has duplicate UUID" which is not correct. > > But anyway, the __GFP_NOFAIL in the call makes this all moot AFAICT. > > -Eric Hi Eric, Sorry for neglecting __GFP_NOFAIL symbol, and I would add a WARN in memory failure next time. Thanks for your advice！ > >> + xfs_uuid_table = if_xfs_uuid_table; >> hole = xfs_uuid_table_size++; >> } >> xfs_uuid_table[hole] = *uuid; >> > . >