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 CFF17C433F5 for ; Sat, 4 Dec 2021 12:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1384963AbhLDNAm (ORCPT ); Sat, 4 Dec 2021 08:00:42 -0500 Received: from mail-eopbgr30068.outbound.protection.outlook.com ([40.107.3.68]:11598 "EHLO EUR03-AM5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S233028AbhLDNAm (ORCPT ); Sat, 4 Dec 2021 08:00:42 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=BmBGCIlONDh0jXbxPh0gDlXUtYorU17FwyJioNyBo0cyjqQMdPvu5O66zSrjzhyIA0WcArQMgrhZ56QovPgxaOKcLRc0TMRx57ibAby1hNweb3RBB5mvBAAFQhTLfU414fGywgi6klOaeEsvT7p5rqwKihvby9Wt6b/HZRO1ZnPfFnX0uf9LnE7/eCHbX/OcN0zEJpB0QxHcizSF5YdS2l7vwSwDCjJmfAqxmlSrpafcY98UyH/XHee9PpNBhHDNqFW8MHUJB4eCFWesVUqMD7hkCu+AGS7v8AGozwkBz1WtkP15E+WITVUKoADM5SaaogpZMvGXrYojUiUXKz8FUw== 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-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=3a7cLOe+p1TiPJ9WvcW0Pkkd57lfglGxHqDCAinEMH4=; b=k5sc2X4JVZ9GzOkbShxAzAML07crcMaJtJ1u01hPAMo9qwPwfYAJVCG74DU6vyNXJvn5m8XKE83ROjzcWhOMHqZeC7s1NjHcsxIEDAruphgazxk+FsAEr5XFgo4XI5OQsrH7LjrKCkO2Icw/9X4I38vQ7hW3GGwBEOP1njsBTvpddXzib9ek7cLFOetd33dSioxvB8IM/rnRfncIN7rsfCIALcygmhEA87IPV7vN/mzCaJDZeqVmsbCsRE2/L/4Bg4QBTIgx9GsBJYwnkfh8qaTGreSsNnatS6XR89YNOkxTvntFMynNTqon1AstNzTGUGvVKF4rhIuwnSIwonoQxA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nxp.com; dmarc=pass action=none header.from=nxp.com; dkim=pass header.d=nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3a7cLOe+p1TiPJ9WvcW0Pkkd57lfglGxHqDCAinEMH4=; b=IJAbtbbQAj9YrFH8AR4VffpMQP02hqc9QM8Fci1qAohJpQVCc/3gjTkWtISAb0zYU7/RGJMiabtNKNSN3SZxm1QxU5wuJvj5eJYuFTUfEMGSI4WkddVz2WKr1FqsFLTP6hBeZCTD7w3xYrgzQHtVoM1WSfLpDHXsKmwH4nNZVAg= Received: from VI1PR04MB5136.eurprd04.prod.outlook.com (2603:10a6:803:55::19) by VI1PR04MB5855.eurprd04.prod.outlook.com (2603:10a6:803:de::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4755.16; Sat, 4 Dec 2021 12:57:08 +0000 Received: from VI1PR04MB5136.eurprd04.prod.outlook.com ([fe80::796e:38c:5706:b802]) by VI1PR04MB5136.eurprd04.prod.outlook.com ([fe80::796e:38c:5706:b802%3]) with mapi id 15.20.4755.020; Sat, 4 Dec 2021 12:57:08 +0000 From: Vladimir Oltean To: Eric Dumazet CC: "David S . Miller" , Jakub Kicinski , netdev , Eric Dumazet , David Laight , David Lebrun Subject: Re: [PATCH v2 net-next] net: fix recent csum changes Thread-Topic: [PATCH v2 net-next] net: fix recent csum changes Thread-Index: AQHX6Mr02OXjnBHhokCw+/skHPdiBawiS0yA Date: Sat, 4 Dec 2021 12:57:08 +0000 Message-ID: <20211204125707.tn2w2uqlphqq23l6@skbuf> References: <20211204045356.3659278-1-eric.dumazet@gmail.com> In-Reply-To: <20211204045356.3659278-1-eric.dumazet@gmail.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nxp.com; x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: fd1c5f81-f8c5-4f80-8e5d-08d9b7259489 x-ms-traffictypediagnostic: VI1PR04MB5855: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-ms-exchange-senderadcheck: 1 x-ms-exchange-antispam-relay: 0 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:VI1PR04MB5136.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(7916004)(366004)(316002)(8936002)(6506007)(508600001)(2906002)(76116006)(6916009)(4326008)(66446008)(71200400001)(91956017)(86362001)(1076003)(5660300002)(38100700002)(122000001)(6486002)(9686003)(66946007)(83380400001)(26005)(33716001)(66476007)(64756008)(54906003)(38070700005)(8676002)(44832011)(66556008)(6512007)(186003);DIR:OUT;SFP:1101; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?LUeuWmS++UmguMz7FXkj9Qnr92Yya9d+aOrIsslfsXLXn2ayubCKlsDbX/5n?= =?us-ascii?Q?j93xRyK56fTYe8K64rvwU54mcN58XCLLeA0ZiZIe1RPRLLOt5bJkNE26sGUO?= =?us-ascii?Q?h7DKUKgiPvgx5QW1ecCxauuDTc2zF8s4IaqGS32C1OBE6JrhB9c1YyEAlmvB?= =?us-ascii?Q?OEwLHFxR4b5I+UgL/gXtTKjrEwsSJmVYV9EV/uddfO2imX+fKXTi6wYG9yPR?= =?us-ascii?Q?QhBpR1aofJyjbiDNfxP8ie9MoIu/DDdLKwHWdOPWM8uBopbPsuULiNRGpUr5?= =?us-ascii?Q?ge3W6fOiNKMA9Vft1xukPNevLkmMnfrk/f+8T2PLg1m9yVkn12ZvsAHcFOoE?= =?us-ascii?Q?dgYf7jcvvrhL4F5X75T4SKCeVdKtLay6xYr0pezZ6SI2EIgr7xQUhjnL3AM+?= =?us-ascii?Q?uPqrBTInFv9T1TFCfhaWE9LJGNFRPev3cwuJEuNEaMo7qHzkwsnyYtftMM9J?= =?us-ascii?Q?YIvU3smSnIHJ2Q+3GtGPRfqIqvop6RzdgzZ66WTQa5ODY64ZU8ULdKnOi6Yw?= =?us-ascii?Q?w0+tqjg9zoHduHEBX9osOjURCiUddJOVDY/q0GLc0s3x/zevkwj+Xn4zi0dK?= =?us-ascii?Q?Y1+oNxiB7luiiEgpsuyni4M+iIMeX3F+W/BQBFiBnmtR1GgO2QrtgkR9NO6L?= =?us-ascii?Q?RLdLTND4cadzMxVt/tY5qyIczL7KVVKUDuI+e7sVaIf0L1gK4RE0SUyHXEyf?= =?us-ascii?Q?3zNAr2mXvR3MYrdz7vS11o80OxfSLUDs7Pol5aQjeIWRm7ZpHvSKA8FKPw24?= =?us-ascii?Q?ESMe0LGId1QZESVYxie4E1AS1nb4DHyqgyvCzTFjLurPQMOPeWEiqDjWFeuP?= =?us-ascii?Q?C8EWg4nb15O5y/hxhHTc6j1PqfWu+75XgPOJZUAPUrPprIzMwuyWSEOrE/Tu?= =?us-ascii?Q?2kBcM/iSdKTBG8a6Wj4ZqD6HHf+FI9SYvT0YcZ7+D+CspojZoA5QV5Y5Sp/4?= =?us-ascii?Q?h0RtYToxhWkx3oubXkpd1rZzbM98YXJVs8R+8mTPlSZiSqe0ADqTDmBs4YkD?= =?us-ascii?Q?+pI71koEoWh/lY3+75ntxz9eL33DO3OF7xH8cwRpm3KZqOpuwgcRR7n6jyPg?= =?us-ascii?Q?VthaXF31KFS7L+MBmj0zU+cmG18l5ot13g3TB0NA+HzC1UPXzZd195l3Mwzn?= =?us-ascii?Q?Critaa4g5A/sp7Kn86rg1Vai/Gsq/LdD/3VHCTeEFkuM1Yqkt3Swi0uFaTc/?= =?us-ascii?Q?6QZn1uO4uNfQeizaecetL1VXLhdMbKyFc3mZBo9xREmMNy3cYc3/H3L5MSPN?= =?us-ascii?Q?6fSKtiuud3FJQYdT4Nq0UnbzHtLmkEGA0oZBgXlaHWwerC+Qv/6uPxemwt5e?= =?us-ascii?Q?mckIxBF4XobDXP5b6XXAjREYRsTYD8cAz5FkvaBmix9qrmHMbShvEFahN2ET?= =?us-ascii?Q?qNrXwjzcP/7XtKF3vbyg/hjCUJ/Jsdx7OlJnnjUvkdsxhMFFvoVSAUmqG/iT?= =?us-ascii?Q?bWZIXF3Mbz8XvV3HIb8B0uz7vLIQN1+1bSFtEH19xzbkLGGB72/4SvPJJlwE?= =?us-ascii?Q?q67T82m6IPFwHlObFia/7rWTQAo19Sq5JfPq/Hj40cOxy5FBABDt6UctztxA?= =?us-ascii?Q?dl8tEZcGQOuTiGDfPDjaWm+KsZoYryQXt5K/iCkRqQsdTuGf9vtxXWEowuIP?= =?us-ascii?Q?/gbjUc6NzfpeScZG1jjn2VM=3D?= Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: VI1PR04MB5136.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: fd1c5f81-f8c5-4f80-8e5d-08d9b7259489 X-MS-Exchange-CrossTenant-originalarrivaltime: 04 Dec 2021 12:57:08.2882 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: fWEhyhJOlIxyV6T4sxE4OCN2Pi8gEahwAPrTq81mBXyq+NN2UW/zzZsRJYZxaybmiDHCCewXZSqaQWaXXtTPyg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR04MB5855 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Dec 03, 2021 at 08:53:56PM -0800, Eric Dumazet wrote: > From: Eric Dumazet >=20 > Vladimir reported csum issues after my recent change in skb_postpull_rcsu= m() >=20 > Issue here is the following: >=20 > initial skb->csum is the csum of >=20 > [part to be pulled][rest of packet] >=20 > Old code: > skb->csum =3D csum_sub(skb->csum, csum_partial(pull, pull_length, 0)); >=20 > New code: > skb->csum =3D ~csum_partial(pull, pull_length, ~skb->csum); >=20 > This is broken if the csum of [pulled part] > happens to be equal to skb->csum, because end > result of skb->csum is 0 in new code, instead > of being 0xffffffff >=20 > David Laight suggested to use >=20 > skb->csum =3D -csum_partial(pull, pull_length, -skb->csum); >=20 > I based my patches on existing code present in include/net/seg6.h, > update_csum_diff4() and update_csum_diff16() which might need > a similar fix. >=20 > I guess that my tests, mostly pulling 40 bytes of IPv6 header > were not providing enough entropy to hit this bug. >=20 > v2: added wsum_negate() to make sparse happy. >=20 > Fixes: 29c3002644bd ("net: optimize skb_postpull_rcsum()") > Fixes: 0bd28476f636 ("gro: optimize skb_gro_postpull_rcsum()") > Signed-off-by: Eric Dumazet > Reported-by: Vladimir Oltean > Suggested-by: David Laight > Cc: David Lebrun > --- Tested-by: Vladimir Oltean Thanks!=