From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by dpdk.space (Postfix) with ESMTP id D88E8A046B for ; Mon, 24 Jun 2019 13:52:27 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 984241BEFD; Mon, 24 Jun 2019 13:52:27 +0200 (CEST) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 47E601BECB; Mon, 24 Jun 2019 13:52:23 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jun 2019 04:52:22 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,412,1557212400"; d="scan'208";a="184111750" Received: from irsmsx151.ger.corp.intel.com ([163.33.192.59]) by fmsmga004.fm.intel.com with ESMTP; 24 Jun 2019 04:52:21 -0700 Received: from irsmsx155.ger.corp.intel.com (163.33.192.3) by IRSMSX151.ger.corp.intel.com (163.33.192.59) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 24 Jun 2019 12:52:07 +0100 Received: from irsmsx104.ger.corp.intel.com ([169.254.5.143]) by irsmsx155.ger.corp.intel.com ([169.254.14.100]) with mapi id 14.03.0439.000; Mon, 24 Jun 2019 12:52:07 +0100 From: "Ananyev, Konstantin" To: Ivan Malov , Olivier Matz CC: "dev@dpdk.org" , "Kulasek, TomaszX" , "stable@dpdk.org" Thread-Topic: [dpdk-dev] [PATCH] net: fix the way how L4 checksum choice is tested Thread-Index: AQHVFkS05fsTOuKkj0m2RBehv7AAr6aq2Qhg Date: Mon, 24 Jun 2019 11:52:05 +0000 Message-ID: <2601191342CEEE43887BDE71AB97725801689E3F22@IRSMSX104.ger.corp.intel.com> References: <20190529173337.31157-1-ivan.malov@oktetlabs.ru> In-Reply-To: <20190529173337.31157-1-ivan.malov@oktetlabs.ru> Accept-Language: en-IE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiNTgzMmE4NTAtMmQzOC00Njk5LWE0ZTMtNzhiYzQ5MDk1NjUyIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoiVU9GYmp1NlpPTmI0VWlBZHZsTXIzUkRlbXNWS1wveEIzV25jQmppd3BcL1NTNVNDcU5nR3lTRjMwUUIzU0dRUHlSIn0= x-ctpclassification: CTP_NT dlp-product: dlpe-windows dlp-version: 11.2.0.6 dlp-reaction: no-action x-originating-ip: [163.33.239.180] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] net: fix the way how L4 checksum choice is tested X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org Sender: "stable" > The API to prepare checksum offloads mistreats L4 > checksum type enum values as self-contained flags. >=20 > Turning these flag checks into enum checks causes > warnings by GCC about possibly uninitialised IPv4 > header pointer. The issue was found to show up in > the case of GCC versions 4.8.5 and 5.4.0, however, > it might be the case for a wider variety of other > versions. As GCC version 7.4.0 is not susceptible > to the said false positive assessment, this patch > maintains a compiler barrier for earlier versions. >=20 > Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation") > Cc: Tomasz Kulasek > Cc: stable@dpdk.org >=20 > Signed-off-by: Ivan Malov > --- > lib/librte_net/rte_net.h | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) >=20 > diff --git a/lib/librte_net/rte_net.h b/lib/librte_net/rte_net.h > index 7088584..fb09431 100644 > --- a/lib/librte_net/rte_net.h > +++ b/lib/librte_net/rte_net.h > @@ -151,7 +151,19 @@ uint32_t rte_net_get_ptype(const struct rte_mbuf *m, > ipv4_hdr->hdr_checksum =3D 0; > } >=20 As I remember, saw something similar before... Probably the eaiser way to overcome it, is just to always initialize ipv4_h= dr above, something like: +ipv4_hdr =3D NULL; if (ol_flags & PKT_TX_IPV4) { ipv4_hdr =3D rte_pktmbuf_mtod_offset(m, struct rte_ipv4_hdr= *, inner_l3_offset); if (ol_flags & PKT_TX_IP_CKSUM) ipv4_hdr->hdr_checksum =3D 0; } > - if ((ol_flags & PKT_TX_UDP_CKSUM) =3D=3D PKT_TX_UDP_CKSUM) { > +#ifdef GCC_VERSION > +#if GCC_VERSION < 70400 > + /* > + * Earlier versions of GCC suspect access to possibly > + * uninitialised ipv4_hdr in the code below, although > + * the said variable is properly initialised above. > + * Use compiler barrier to cope with the problem. > + */ > + rte_compiler_barrier(); > +#endif > +#endif > + > + if ((ol_flags & PKT_TX_L4_MASK) =3D=3D PKT_TX_UDP_CKSUM) { > if (ol_flags & PKT_TX_IPV4) { > udp_hdr =3D (struct rte_udp_hdr *)((char *)ipv4_hdr + > m->l3_len); > @@ -167,7 +179,7 @@ uint32_t rte_net_get_ptype(const struct rte_mbuf *m, > udp_hdr->dgram_cksum =3D rte_ipv6_phdr_cksum(ipv6_hdr, > ol_flags); > } > - } else if ((ol_flags & PKT_TX_TCP_CKSUM) || > + } else if ((ol_flags & PKT_TX_L4_MASK) =3D=3D PKT_TX_TCP_CKSUM || > (ol_flags & PKT_TX_TCP_SEG)) { > if (ol_flags & PKT_TX_IPV4) { > /* non-TSO tcp or TSO */ > -- > 1.8.3.1