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=-13.0 required=3.0 tests=BAYES_00,HK_RANDOM_FROM, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE 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 C12E3C433DB for ; Thu, 14 Jan 2021 14:22:22 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5E24A23A6A for ; Thu, 14 Jan 2021 14:22:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E24A23A6A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bu.edu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59484 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l03W1-0006mr-7m for qemu-devel@archiver.kernel.org; Thu, 14 Jan 2021 09:22:21 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35584) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l03Ti-00056E-KJ for qemu-devel@nongnu.org; Thu, 14 Jan 2021 09:19:58 -0500 Received: from relay68.bu.edu ([128.197.228.73]:39044) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l03Tg-00079C-Jq for qemu-devel@nongnu.org; Thu, 14 Jan 2021 09:19:57 -0500 X-Envelope-From: alxndr@bu.edu X-BU-AUTH: mozz.bu.edu [128.197.127.33] Received: from BU-AUTH (localhost.localdomain [127.0.0.1]) (authenticated bits=0) by relay68.bu.edu (8.14.3/8.14.3) with ESMTP id 10EEJKZi015100 (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Thu, 14 Jan 2021 09:19:23 -0500 Date: Thu, 14 Jan 2021 09:19:20 -0500 From: Alexander Bulekov To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v3 1/2] Fix net.c warning on GCC 11 Message-ID: <20210114141920.qjsnlt3cmkauggtw@mozz.bu.edu> References: <4fd8d2a3-e665-4422-79e0-4e2a7337e4fc@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4fd8d2a3-e665-4422-79e0-4e2a7337e4fc@redhat.com> Received-SPF: pass client-ip=128.197.228.73; envelope-from=alxndr@bu.edu; helo=relay68.bu.edu X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=0.998, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Miroslav Rezanina , Dmitry Fleytman , Jason Wang , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 210114 1415, Philippe Mathieu-Daudé wrote: > +Jason +Dmitry > > On 1/14/21 8:07 AM, Miroslav Rezanina wrote: > > When building qemu with GCC 11, compiling eth.c file produce following warning: > > > > warning: array subscript 'struct ip6_ext_hdr_routing[0]' is partly outside array bounds of 'struct ip6_ext_hdr[1]' [-Warray-bounds] > > > > This is caused by retyping from ip6_ext_hdr to ip6_ext_hdr_routing that has more > > attributes. > > > > As this usage is expected, suppress the warning temporarily through the function > > using this retyping. > > This is not expected, this is a bug... > Seems related: https://bugs.launchpad.net/qemu/+bug/1879531 -Alex > > > > Signed-off-by: Miroslav Rezanina > > --- > > net/eth.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/net/eth.c b/net/eth.c > > index 1e0821c5f8..b9bdd0435c 100644 > > --- a/net/eth.c > > +++ b/net/eth.c > > @@ -405,6 +405,8 @@ _eth_get_rss_ex_dst_addr(const struct iovec *pkt, int pkt_frags, > > struct ip6_ext_hdr *ext_hdr, > > struct in6_address *dst_addr) > > { > > +#pragma GCC diagnostic push > > +#pragma GCC diagnostic ignored "-Warray-bounds" > > struct ip6_ext_hdr_routing *rthdr = (struct ip6_ext_hdr_routing *) ext_hdr; > > eth_parse_ipv6_hdr() called iov_to_buf() to fill the 2 bytes of ext_hdr. > > > if ((rthdr->rtype == 2) && > > Here we access after the 2 bytes filled... rthdr->rtype is somewhere on > eth_parse_ipv6_hdr's stack, its content is unknown. > > > @@ -426,6 +428,7 @@ _eth_get_rss_ex_dst_addr(const struct iovec *pkt, int pkt_frags, > > } > > > > return false; > > +#pragma GCC diagnostic pop > > Nacked-by: Philippe Mathieu-Daudé > >