From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:53748) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hF3XT-0008Mv-CA for qemu-devel@nongnu.org; Fri, 12 Apr 2019 17:16:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hF3XR-0002VW-B1 for qemu-devel@nongnu.org; Fri, 12 Apr 2019 17:16:47 -0400 Received: from hera.aquilenet.fr ([2a0c:e300::1]:52708) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hF3XP-0002QC-5a for qemu-devel@nongnu.org; Fri, 12 Apr 2019 17:16:43 -0400 Date: Fri, 12 Apr 2019 23:16:33 +0200 From: Samuel Thibault Message-ID: <20190412211633.6pyn6cfm5dnwjzji@function> References: <20190405184648.17029-1-dgilbert@redhat.com> <20190405212501.cdg4u3m7ihldcop4@function> <20190408084653.GB2687@work-vm> <20190411184502.xvesnriqcocyvuan@function> <20190412154942.GF2906@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190412154942.GF2906@work-vm> Subject: Re: [Qemu-devel] [PATCH] slirp: Gcc 9 -O3 fix List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: qemu-devel@nongnu.org, jan.kiszka@siemens.com Dr. David Alan Gilbert, le ven. 12 avril 2019 16:49:42 +0100, a ecrit: > * 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? It does not really make sense to, so an assert >0 should be fine. Samuel 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=-2.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 D7506C10F0E for ; Fri, 12 Apr 2019 21:17:43 +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 A79EE2171F for ; Fri, 12 Apr 2019 21:17:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A79EE2171F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gnu.org 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]:42816 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hF3YN-0000SH-0r for qemu-devel@archiver.kernel.org; Fri, 12 Apr 2019 17:17:43 -0400 Received: from eggs.gnu.org ([209.51.188.92]:53748) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hF3XT-0008Mv-CA for qemu-devel@nongnu.org; Fri, 12 Apr 2019 17:16:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hF3XR-0002VW-B1 for qemu-devel@nongnu.org; Fri, 12 Apr 2019 17:16:47 -0400 Received: from hera.aquilenet.fr ([2a0c:e300::1]:52708) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hF3XP-0002QC-5a for qemu-devel@nongnu.org; Fri, 12 Apr 2019 17:16:43 -0400 Received: from localhost (localhost [127.0.0.1]) by hera.aquilenet.fr (Postfix) with ESMTP id 0E855AEC5; Fri, 12 Apr 2019 23:16:36 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at aquilenet.fr Received: from hera.aquilenet.fr ([127.0.0.1]) by localhost (hera.aquilenet.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wzRFS3PL1omn; Fri, 12 Apr 2019 23:16:34 +0200 (CEST) Received: from function (105.251.129.77.rev.sfr.net [77.129.251.105]) by hera.aquilenet.fr (Postfix) with ESMTPSA id 863EBAEC3; Fri, 12 Apr 2019 23:16:34 +0200 (CEST) Received: from samy by function with local (Exim 4.92) (envelope-from ) id 1hF3XF-0007tL-KY; Fri, 12 Apr 2019 23:16:33 +0200 Date: Fri, 12 Apr 2019 23:16:33 +0200 From: Samuel Thibault To: "Dr. David Alan Gilbert" Message-ID: <20190412211633.6pyn6cfm5dnwjzji@function> References: <20190405184648.17029-1-dgilbert@redhat.com> <20190405212501.cdg4u3m7ihldcop4@function> <20190408084653.GB2687@work-vm> <20190411184502.xvesnriqcocyvuan@function> <20190412154942.GF2906@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190412154942.GF2906@work-vm> Organization: I am not organized User-Agent: NeoMutt/20170113 (1.7.2) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a0c:e300::1 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: <20190412211633.Otw0TLqTbeIJABj1PSvqMTwir97guPqFQQKXtBwnhhE@z> Dr. David Alan Gilbert, le ven. 12 avril 2019 16:49:42 +0100, a ecrit: > * 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? It does not really make sense to, so an assert >0 should be fine. Samuel