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=ham 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 384C8C433EF for ; Wed, 22 Sep 2021 12:21:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 16D3C610A1 for ; Wed, 22 Sep 2021 12:21:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234760AbhIVMXK (ORCPT ); Wed, 22 Sep 2021 08:23:10 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:9756 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233626AbhIVMXJ (ORCPT ); Wed, 22 Sep 2021 08:23:09 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HDy701J3MzWCST; Wed, 22 Sep 2021 20:20:28 +0800 (CST) Received: from dggema762-chm.china.huawei.com (10.1.198.204) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.8; Wed, 22 Sep 2021 20:21:27 +0800 Received: from [10.174.176.73] (10.174.176.73) by dggema762-chm.china.huawei.com (10.1.198.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Wed, 22 Sep 2021 20:21:26 +0800 Subject: Re: [patch v8 3/7] nbd: check sock index in nbd_read_stat() To: Ming Lei CC: , , , , , , References: <20210916093350.1410403-1-yukuai3@huawei.com> <20210916093350.1410403-4-yukuai3@huawei.com> <7e2913ca-1089-9ab7-cfdb-5e8837d36034@huawei.com> From: "yukuai (C)" Message-ID: <3bfd595e-20a6-c4ab-b041-9bca28a4584f@huawei.com> Date: Wed, 22 Sep 2021 20:21:26 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.176.73] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggema762-chm.china.huawei.com (10.1.198.204) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2021/09/22 17:22, Ming Lei wrote: > On Sun, Sep 19, 2021 at 06:34:28PM +0800, yukuai (C) wrote: >> On 2021/09/16 17:33, Yu Kuai wrote: >>> The sock that clent send request in nbd_send_cmd() and receive reply >>> in nbd_read_stat() should be the same. >>> >>> Signed-off-by: Yu Kuai >>> --- >>> drivers/block/nbd.c | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c >>> index 614c6ab2b8fe..c724a5bd7fa4 100644 >>> --- a/drivers/block/nbd.c >>> +++ b/drivers/block/nbd.c >>> @@ -746,6 +746,10 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) >>> ret = -ENOENT; >>> goto out; >>> } >>> + if (cmd->index != index) { >>> + dev_err(disk_to_dev(nbd->disk), "Unexpected reply %d from different sock %d (expected %d)", >>> + tag, index, cmd->index); >>> + } >>> if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) { >>> dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n", >>> req, cmd->cmd_cookie, nbd_handle_to_cookie(handle)); >>> >> >> Hi, Ming >> >> Any suggestions about this patch? > > I think this one relies on nbd protocol between server and client, and > does the protocol require both request and reply xmitted via same > socket? > I searched nbd-server source code, and found that socket_read() and send_reply->socket_write() are always come in pares and using the same socket. BTW, if server reply a read request from a unexpected sock, then nbd_read_stat() might stuck in receiving the read data. And for worse, nbd_read_stat() can mistake the normal reply message for the read data afterwards and corrupt client. Thanks, Kuai