From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:40239) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEyR2-0002hn-A7 for qemu-devel@nongnu.org; Fri, 12 Apr 2019 11:49:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hEyR1-00088L-Cm for qemu-devel@nongnu.org; Fri, 12 Apr 2019 11:49:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59636) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hEyR1-000883-4X for qemu-devel@nongnu.org; Fri, 12 Apr 2019 11:49:47 -0400 Date: Fri, 12 Apr 2019 16:49:42 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20190412154942.GF2906@work-vm> References: <20190405184648.17029-1-dgilbert@redhat.com> <20190405212501.cdg4u3m7ihldcop4@function> <20190408084653.GB2687@work-vm> <20190411184502.xvesnriqcocyvuan@function> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190411184502.xvesnriqcocyvuan@function> Subject: Re: [Qemu-devel] [PATCH] slirp: Gcc 9 -O3 fix List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Samuel Thibault Cc: qemu-devel@nongnu.org, jan.kiszka@siemens.com * Samuel Thibault (samuel.thibault@gnu.org) wrote: > Hello, > > Dr. David Alan Gilbert, le lun. 08 avril 2019 09:46:53 +0100, a ecrit: > > 'soread' has the comment: > > > > /* > > * No need to check if there's enough room to read. > > * soread wouldn't have been called if there weren't > > */ > > sopreprbuf(so, iov, &n); > > > > the compiler doesn't realise that, and is moaning about the case > > where the if (len <=0) return happens and the following > > code tries to use iov. > > I see. Perhaps we should make this an assert then? In case this isn't > true, i.e. soread() is called even if no room is available, returning 0 > would probably just let the caller just try again, and we should rather > just plainly crash than hang? Adding the assert in soread sorts that case out: assert(sopreprbuf(so, iov, &n) != 0); however, I also need to fix soreadbuf; is it legal to call that with a 0 size? Dave > Samuel -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK 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=-2.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,T_HK_NAME_DR,URIBL_BLOCKED,USER_AGENT_MUTT 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 EC116C10F0E for ; Fri, 12 Apr 2019 15:51:39 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B0C7220693 for ; Fri, 12 Apr 2019 15:51:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B0C7220693 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:39025 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEySo-0004EP-SU for qemu-devel@archiver.kernel.org; Fri, 12 Apr 2019 11:51:38 -0400 Received: from eggs.gnu.org ([209.51.188.92]:40239) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEyR2-0002hn-A7 for qemu-devel@nongnu.org; Fri, 12 Apr 2019 11:49:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hEyR1-00088L-Cm for qemu-devel@nongnu.org; Fri, 12 Apr 2019 11:49:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59636) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hEyR1-000883-4X for qemu-devel@nongnu.org; Fri, 12 Apr 2019 11:49:47 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2C05A30821A0; Fri, 12 Apr 2019 15:49:46 +0000 (UTC) Received: from work-vm (unknown [10.36.117.255]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EB7BE1001E67; Fri, 12 Apr 2019 15:49:44 +0000 (UTC) Date: Fri, 12 Apr 2019 16:49:42 +0100 From: "Dr. David Alan Gilbert" To: Samuel Thibault Message-ID: <20190412154942.GF2906@work-vm> References: <20190405184648.17029-1-dgilbert@redhat.com> <20190405212501.cdg4u3m7ihldcop4@function> <20190408084653.GB2687@work-vm> <20190411184502.xvesnriqcocyvuan@function> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190411184502.xvesnriqcocyvuan@function> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Fri, 12 Apr 2019 15:49:46 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH] slirp: Gcc 9 -O3 fix X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jan.kiszka@siemens.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190412154942.AF2x80xzF83hV3XPImKna62iiBJElKoC_9TmHelqib4@z> * Samuel Thibault (samuel.thibault@gnu.org) wrote: > Hello, > > Dr. David Alan Gilbert, le lun. 08 avril 2019 09:46:53 +0100, a ecrit: > > 'soread' has the comment: > > > > /* > > * No need to check if there's enough room to read. > > * soread wouldn't have been called if there weren't > > */ > > sopreprbuf(so, iov, &n); > > > > the compiler doesn't realise that, and is moaning about the case > > where the if (len <=0) return happens and the following > > code tries to use iov. > > I see. Perhaps we should make this an assert then? In case this isn't > true, i.e. soread() is called even if no room is available, returning 0 > would probably just let the caller just try again, and we should rather > just plainly crash than hang? Adding the assert in soread sorts that case out: assert(sopreprbuf(so, iov, &n) != 0); however, I also need to fix soreadbuf; is it legal to call that with a 0 size? Dave > Samuel -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK