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=-11.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 4B054C4727C for ; Tue, 22 Sep 2020 07:13:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E38C3207C3 for ; Tue, 22 Sep 2020 07:13:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=windriversystems.onmicrosoft.com header.i=@windriversystems.onmicrosoft.com header.b="LMcurrL9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729768AbgIVHN0 (ORCPT ); Tue, 22 Sep 2020 03:13:26 -0400 Received: from mail-mw2nam10on2077.outbound.protection.outlook.com ([40.107.94.77]:9791 "EHLO NAM10-MW2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728526AbgIVHNZ (ORCPT ); Tue, 22 Sep 2020 03:13:25 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=nSshHqcdTVj5EXjdgaq2EqCH6TiVqi5h7QNqsYRDgUN5OiFC55PMAfwZkrHZO6KPExcHsvYHNXQN6QWNp93+mNbWV0TbDfhbpAaU33NwMdjQIfu/G8ofygfELY3vMmj4UZGxXKuSlLPENu16KWfrLL9yhhZ6s4ZwuEasNVLdnicvu3kUqD63iXihByQZ2cmLeknLjvm5UCBPPvVhhgpAqvreQqrvEpO07jOHxnQLqqMbVS4EsVSAysqjdCKz4pJOK117xZ9QdNYcnNcv40/95dOeG/M+aBrw/qXCOIC/AsmfvD7JI6F38oSyV+DqiwtubGBBdH4mDdolPwlKOYzq1A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=yhZ5Bby6cSbL9Ie1syzqNxQf/n8VGdxooLRWVbfFNlk=; b=DiwKOnFl0W38WSt2oFNhXpq5bIuq0Ekd4Ul/9wDcJy9Msgu5zgquIwTpheMQ8aNxouiIU6NZbK+X8Ij9xAxGXZKOa8r0cAHIKJPRhULak3evP/b+NcfkYZ4ebA+UVenVlFt4XXx+wguXgzD/L/nW2RBFNdaufff8voqdKolShdTCGsjM0fVQBsYKPvrBWhMATzP9t82gX2rNYxsL2RXlnpMSsOsrHcO42i1GGEPas9Shbw7l7yN0ftZkRUYezCWPKZySaLlDnxj5Yhp0s+SCKIS0rAQn2ssGwokLd8eFikcS7WehCH70YrWF5uTpt9sL8qcdttv85Z+3j6etf5It8A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=windriver.com; dmarc=pass action=none header.from=windriver.com; dkim=pass header.d=windriver.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=windriversystems.onmicrosoft.com; s=selector2-windriversystems-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=yhZ5Bby6cSbL9Ie1syzqNxQf/n8VGdxooLRWVbfFNlk=; b=LMcurrL9mwAlD/pKvxWGXujzUw5kupZR5QdvMrM7mbHki50IDOGMqAbB1RRjXlYp63d8ejIauuxdqjPh3xYZcCjB2QB90ro37VUsD47d6GaJugQtk8HxVXpfRJnlXGNxKi8twGVEMFOETfKZZp+pVURwbhIpdOWIPS547m6DlKk= Authentication-Results: kernel.org; dkim=none (message not signed) header.d=none;kernel.org; dmarc=none action=none header.from=windriver.com; Received: from SN6PR11MB3360.namprd11.prod.outlook.com (2603:10b6:805:c8::30) by SN6PR11MB2557.namprd11.prod.outlook.com (2603:10b6:805:56::33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3391.14; Tue, 22 Sep 2020 07:13:22 +0000 Received: from SN6PR11MB3360.namprd11.prod.outlook.com ([fe80::4dbe:2ab5:9b68:a966]) by SN6PR11MB3360.namprd11.prod.outlook.com ([fe80::4dbe:2ab5:9b68:a966%7]) with mapi id 15.20.3412.020; Tue, 22 Sep 2020 07:13:22 +0000 Subject: Re: [PATCH] SUNRPC: Fix svc_flush_dcache() To: Chuck Lever Cc: linux-nfs@vger.kernel.org, "open list:NETWORKING DRIVERS" , LKML , Bruce Fields , Trond Myklebust , Anna Schumaker , "David S . Miller" , Jakub Kicinski References: <160063136387.1537.11599713172507546412.stgit@klimt.1015granger.net> From: He Zhe Message-ID: <07c27f89-187b-69a3-fd40-f9beef29da40@windriver.com> Date: Tue, 22 Sep 2020 15:13:14 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 In-Reply-To: <160063136387.1537.11599713172507546412.stgit@klimt.1015granger.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [60.247.85.82] X-ClientProxiedBy: HKAPR03CA0006.apcprd03.prod.outlook.com (2603:1096:203:c8::11) To SN6PR11MB3360.namprd11.prod.outlook.com (2603:10b6:805:c8::30) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [128.224.162.175] (60.247.85.82) by HKAPR03CA0006.apcprd03.prod.outlook.com (2603:1096:203:c8::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3412.4 via Frontend Transport; Tue, 22 Sep 2020 07:13:19 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 262792d6-a33e-43d2-4e43-08d85ec6fd7b X-MS-TrafficTypeDiagnostic: SN6PR11MB2557: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:3383; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: xdc85fTxM2Km4CVGkU7T7vuKQR5mDi0/j0wMptNA4M9cFYDmISkrV5Nsf+7CP3O1Ez08TiteLEAFwIhPUyvbXRGIFxZqfqRoSV6Sxtan02u1QMdh/L3NcLL+mq18+nWWOyM75r7eAWJbatXsLBnW/sSPBuw3jZ72cXub+fKo/ERbALkVyvuui142fB+WdqvwV9Zdmml26Kv7Q9bQMCFcUHmgq00jgrb6wx5A+sEbzbacCJ+P9f8VDC8qHqfdIgth2PatIEyVfiBZIF86TEpZXerO+vWgXxmzy2hQuLd3X1Iam5WWS1ksUrZY8oVOo1G3y1W1KTidTqDf+N3Y5JrWXmXMWgong2n9vghmHsGUaEq8Liqd01Ml1xm5GpSXT+mpJz5urYsVLG3FjtZRHN7HQA== X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN6PR11MB3360.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(366004)(376002)(346002)(136003)(39850400004)(396003)(6486002)(66476007)(66556008)(8676002)(5660300002)(66946007)(52116002)(83380400001)(31686004)(2906002)(6666004)(2616005)(478600001)(956004)(316002)(4326008)(6916009)(53546011)(186003)(6706004)(31696002)(16526019)(8936002)(36756003)(54906003)(26005)(86362001)(16576012)(78286007)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: windriver.com X-MS-Exchange-CrossTenant-Network-Message-Id: 262792d6-a33e-43d2-4e43-08d85ec6fd7b X-MS-Exchange-CrossTenant-AuthSource: SN6PR11MB3360.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Sep 2020 07:13:22.5705 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 8ddb2873-a1ad-4a18-ae4e-4644631433be X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Bl11E+2hSa2UC/0O9G+l2ea2T0TFd7119jXqZTxW4gVlRRmIpHESDqE5g2ttxi44wy3hlFo8l0MLcka6Rflpbg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN6PR11MB2557 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/21/20 3:51 AM, Chuck Lever wrote: > On platforms that implement flush_dcache_page(), a large NFS WRITE > triggers the WARN_ONCE in bvec_iter_advance(): > > Sep 20 14:01:05 klimt.1015granger.net kernel: Attempted to advance past end of bvec iter > Sep 20 14:01:05 klimt.1015granger.net kernel: WARNING: CPU: 0 PID: 1032 at include/linux/bvec.h:101 bvec_iter_advance.isra.0+0xa7/0x158 [sunrpc] > > Sep 20 14:01:05 klimt.1015granger.net kernel: Call Trace: > Sep 20 14:01:05 klimt.1015granger.net kernel: svc_tcp_recvfrom+0x60c/0x12c7 [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? bvec_iter_advance.isra.0+0x158/0x158 [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? del_timer_sync+0x4b/0x55 > Sep 20 14:01:05 klimt.1015granger.net kernel: ? test_bit+0x1d/0x27 [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: svc_recv+0x1193/0x15e4 [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? try_to_freeze.isra.0+0x6f/0x6f [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? refcount_sub_and_test.constprop.0+0x13/0x40 [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? svc_xprt_put+0x1e/0x29f [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? svc_send+0x39f/0x3c1 [sunrpc] > Sep 20 14:01:05 klimt.1015granger.net kernel: nfsd+0x282/0x345 [nfsd] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? __kthread_parkme+0x74/0xba > Sep 20 14:01:05 klimt.1015granger.net kernel: kthread+0x2ad/0x2bc > Sep 20 14:01:05 klimt.1015granger.net kernel: ? nfsd_destroy+0x124/0x124 [nfsd] > Sep 20 14:01:05 klimt.1015granger.net kernel: ? test_bit+0x1d/0x27 > Sep 20 14:01:05 klimt.1015granger.net kernel: ? kthread_mod_delayed_work+0x115/0x115 > Sep 20 14:01:05 klimt.1015granger.net kernel: ret_from_fork+0x22/0x30 > > Reported-by: He Zhe > Fixes: ca07eda33e01 ("SUNRPC: Refactor svc_recvfrom()") > Signed-off-by: Chuck Lever > --- > net/sunrpc/svcsock.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Hi Zhe- > > If you confirm this fixes your issue and there are no other > objections or regressions, I can submit this for v5.9-rc. I don't quite get why we add "seek" to "size". It seems this action does not reflect the actual scenario and forcedly neutralizes the WARN_ONCE check in bvec_iter_advance, so that it may "advance past end of bvec iter" and thus introduces overflow. Why don't we avoid this problem at the very begginning like my v1? That is, call svc_flush_bvec only when we have received more than we want to seek.         len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT); -       if (len > 0) +       if (len > 0 && (size_t)len > (seek & PAGE_MASK))                 svc_flush_bvec(bvec, len, seek); Regards, Zhe > > > diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c > index d5805fa1d066..c2752e2b9ce3 100644 > --- a/net/sunrpc/svcsock.c > +++ b/net/sunrpc/svcsock.c > @@ -228,7 +228,7 @@ static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining) > static void svc_flush_bvec(const struct bio_vec *bvec, size_t size, size_t seek) > { > struct bvec_iter bi = { > - .bi_size = size, > + .bi_size = size + seek, > }; > struct bio_vec bv; > > > >