From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 117469 invoked by alias); 22 Mar 2016 17:57:01 -0000 Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org Received: (qmail 117436 invoked by uid 89); 22 Mar 2016 17:56:59 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY autolearn=no version=3.3.2 spammy=Corporate, Siemens, siemens, his X-HELO: goliath.siemens.de Received: from goliath.siemens.de (HELO goliath.siemens.de) (192.35.17.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Tue, 22 Mar 2016 17:56:52 +0000 Received: from mail1.siemens.de (mail1.siemens.de [139.23.33.14]) by goliath.siemens.de (8.15.2/8.15.2) with ESMTPS id u2MHumOf018047 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 22 Mar 2016 18:56:48 +0100 Received: from md1f2u6c.ww002.siemens.net ([139.25.68.37]) by mail1.siemens.de (8.15.2/8.15.2) with ESMTP id u2MHuljq008056; Tue, 22 Mar 2016 18:56:47 +0100 Subject: Re: gdb.Value returning a string of length 1 (linux lx-version bug) To: Kieran Bingham , Peter Griffin , gdb@sourceware.org References: <56F186C1.1080803@linaro.org> From: Jan Kiszka Message-ID: <56F18761.8030901@siemens.com> Date: Tue, 22 Mar 2016 17:57:00 -0000 User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 In-Reply-To: <56F186C1.1080803@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2016-03/txt/msg00032.txt.bz2 Hi Kieran, On 2016-03-22 18:54, Kieran Bingham wrote: > Hi Jan, > > Me and Pete have just been looking into the gdb.Value object bug where > the lx-version command returns a string of length 1. > > As I recall at FOSDEM, you were also hitting the bug. > Out of interest, what compiler version are you using? gcc (SUSE Linux) 4.8.3 20140627 [gcc-4_8-branch revision 212064] > > We've made some head way, but we are suspicious that compiler versions > may affect the issue ! :( > > The crux of the issue, is that the valpy_string() calls c_get_string() > which in turn calls get_discrete_bounds(). > > On my broken version, get_discrete_bounds, is setting both lowp, and > highp to 0x0; where as on Peters working version, his highp gets set > correctly. (there is a +1 added later which results in the string > producing a strlen of 1) > > I'm running gcc 5.2.1-22ubuntu2, whereas Pete is running gcc 4.8.4. > > Pete's version of his compiled binutils-gdb always seems to function > correctly, where as I hit the bug - *occasionally* > > Of course, since I have compiled with -g3 -O0 -fsanitize=undefined I > can't reproduce the issue, and now even removing the optimise levels I > haven't been able to reproduce. > > We have a Heisenbug :( Maybe wait for someone seeing this more reproducibly? :-/ Jan > > Has anyone else on the GDB Mailinglist experienced any intermittent > errors with gdb.Value strings from python? > -- > Kieran > -- Siemens AG, Corporate Technology, CT RDA ITP SES-DE Corporate Competence Center Embedded Linux