From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/5113 Path: news.gmane.org!not-for-mail From: "Matias A. Fonzo" Newsgroups: gmane.linux.lib.musl.general Subject: Re: Broken GCC versions: 4.8.2 and 4.9.0 Date: Sun, 11 May 2014 17:20:55 -0300 Message-ID: References: <20140511010503.GA6502@brightrain.aerifal.cx> <20140511181020.0a8b66f1@free-electrons.com> <20140511161943.GR26358@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1399839677 10314 80.91.229.3 (11 May 2014 20:21:17 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 11 May 2014 20:21:17 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-5118-gllmg-musl=m.gmane.org@lists.openwall.com Sun May 11 22:21:09 2014 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1WjaFA-0004BI-Ii for gllmg-musl@plane.gmane.org; Sun, 11 May 2014 22:21:08 +0200 Original-Received: (qmail 19518 invoked by uid 550); 11 May 2014 20:21:08 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 19510 invoked from network); 11 May 2014 20:21:07 -0000 In-Reply-To: <20140511161943.GR26358@brightrain.aerifal.cx> X-Sender: selk@dragora.org User-Agent: Roundcube Webmail/0.9.5 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - titan.astranetwork.net X-AntiAbuse: Original Domain - lists.openwall.com X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - dragora.org X-Get-Message-Sender-Via: titan.astranetwork.net: authenticated_id: selk@dragora.org Xref: news.gmane.org gmane.linux.lib.musl.general:5113 Archived-At: Hi dalias, On 2014-05-11 13:19, Rich Felker wrote: > On Sun, May 11, 2014 at 06:10:20PM +0200, Thomas Petazzoni wrote: >> >> On Sat, 10 May 2014 21:05:03 -0400, Rich Felker wrote: >> >> > It's come to my attention that GCC versions 4.8.2 and 4.9.0 are >> > performing invalid optimizations that result in a broken musl >> > libc.a/libc.so. It's not clear yet whether there's a good workaround, >> > or whether we should attempt to work around the problem, so for now, >> > please just be aware that these versions of GCC cannot be used to >> > compile musl. Using them to compile programs against musl should not >> > be a problem. I'll post more details later. The short version is that >> > it's making incorrect assumptions about the reachability of global >> > variables that have a local weak definition and an external strong >> > one. >> >> Hum, interesting. I've recently tested gcc 4.8.2 + musl on ARM, and >> gcc >> 4.9.0 + musl on i386, and I could boot a minimal musl+Busybox system >> under Qemu perfectly fine. Maybe the problem you refer to only affects >> certain parts of libc.a/libc.so? > > I've filed the bug report which you can see here: > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61144 > > Something like the following command should confirm whether your build > is affected: > > nm src/stdio/fflush.o | grep stdout > > For broken gcc versions, there is no output. For non-broken ones, you > should see something like: > > 00000000 V __stdout_used I can confirm that I'm getting in Dragora (binutils 2.23.2, GCC 4.8.2 + musl 1.1.0): 0000000000000000 V __stdout_used I was getting scared.. :-)