From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:55200) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hG0Jv-0004AJ-5b for qemu-devel@nongnu.org; Mon, 15 Apr 2019 08:02:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hG0Jt-0003JX-79 for qemu-devel@nongnu.org; Mon, 15 Apr 2019 08:02:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39678) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hG0Js-0003J4-Uj for qemu-devel@nongnu.org; Mon, 15 Apr 2019 08:02:41 -0400 Date: Mon, 15 Apr 2019 13:02:36 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20190415120236.GJ2852@work-vm> References: <20190405184648.17029-1-dgilbert@redhat.com> <20190405212501.cdg4u3m7ihldcop4@function> <20190408084653.GB2687@work-vm> <20190411184502.xvesnriqcocyvuan@function> <20190412154942.GF2906@work-vm> <20190412211633.6pyn6cfm5dnwjzji@function> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190412211633.6pyn6cfm5dnwjzji@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: > 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. OK, replacement patch with just a couple of asserts sent. 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 64D9DC10F12 for ; Mon, 15 Apr 2019 12:04:10 +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 3821C206BA for ; Mon, 15 Apr 2019 12:04:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3821C206BA 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]:49285 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hG0LJ-0004oX-Eg for qemu-devel@archiver.kernel.org; Mon, 15 Apr 2019 08:04:09 -0400 Received: from eggs.gnu.org ([209.51.188.92]:55200) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hG0Jv-0004AJ-5b for qemu-devel@nongnu.org; Mon, 15 Apr 2019 08:02:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hG0Jt-0003JX-79 for qemu-devel@nongnu.org; Mon, 15 Apr 2019 08:02:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39678) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hG0Js-0003J4-Uj for qemu-devel@nongnu.org; Mon, 15 Apr 2019 08:02:41 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3B4683024552; Mon, 15 Apr 2019 12:02:40 +0000 (UTC) Received: from work-vm (ovpn-117-222.ams2.redhat.com [10.36.117.222]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6233260F9B; Mon, 15 Apr 2019 12:02:39 +0000 (UTC) Date: Mon, 15 Apr 2019 13:02:36 +0100 From: "Dr. David Alan Gilbert" To: Samuel Thibault Message-ID: <20190415120236.GJ2852@work-vm> References: <20190405184648.17029-1-dgilbert@redhat.com> <20190405212501.cdg4u3m7ihldcop4@function> <20190408084653.GB2687@work-vm> <20190411184502.xvesnriqcocyvuan@function> <20190412154942.GF2906@work-vm> <20190412211633.6pyn6cfm5dnwjzji@function> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190412211633.6pyn6cfm5dnwjzji@function> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Mon, 15 Apr 2019 12:02:40 +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: <20190415120236.DbmK6xtV9FKYzGpsQ95lIjPOcYw6ZFFDwNlkdsaNgow@z> * Samuel Thibault (samuel.thibault@gnu.org) wrote: > 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. OK, replacement patch with just a couple of asserts sent. Dave > Samuel -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK