From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11113 Path: news.gmane.org!.POSTED!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: musl segfaulting when compiled with -O2 Date: Tue, 7 Mar 2017 16:45:40 -0500 Message-ID: <20170307214540.GU1520@brightrain.aerifal.cx> References: <20170307203234.GC18936@gmail.com> <20170307203905.GT1520@brightrain.aerifal.cx> <20170307205529.GD18936@gmail.com> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1488923161 2009 195.159.176.226 (7 Mar 2017 21:46:01 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 7 Mar 2017 21:46:01 +0000 (UTC) User-Agent: Mutt/1.5.21 (2010-09-15) To: musl@lists.openwall.com Original-X-From: musl-return-11128-gllmg-musl=m.gmane.org@lists.openwall.com Tue Mar 07 22:45:56 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1clMvV-0007h1-6Q for gllmg-musl@m.gmane.org; Tue, 07 Mar 2017 22:45:49 +0100 Original-Received: (qmail 20125 invoked by uid 550); 7 Mar 2017 21:45:53 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 20090 invoked from network); 7 Mar 2017 21:45:52 -0000 Content-Disposition: inline In-Reply-To: <20170307205529.GD18936@gmail.com> Original-Sender: Rich Felker Xref: news.gmane.org gmane.linux.lib.musl.general:11113 Archived-At: On Tue, Mar 07, 2017 at 05:55:29PM -0300, Breno Leitao wrote: > Hi Rich, > > On Tue, Mar 07, 2017 at 03:39:05PM -0500, Rich Felker wrote: > > On Tue, Mar 07, 2017 at 05:32:35PM -0300, Breno Leitao wrote: > > > Musl package on Debian on ppc64le is broken. > > > > > > When running any software with it, it segfaults. Doing a little bit of > > > debugging I found that libc.so is broken. > > > > > > I got the upstream code, and found that the problme is also > > > reproducible. > > > > > > I found that the problem only happen when compiling with -O2 and -O3. If > > > I compile musl with -O1 or -O0, the problm does not happen. > > > > > > This is the bt of the code that crashes: > > > > > > (gdb) bt > > > #0 0x0000000148b84dc0 in ?? () > > > #1 0x0000000048bdb8dc in _dlstart_c (sp=0x3fffc33294b0, dynv=) at ldso/dlstart.c:147 > > > #2 0x0000000048bdebe0 in _dlstart () > > > > > > (gdb) up > > > #1 0x0000000048bdb8dc in _dlstart_c (sp=0x3fffc33294b0, dynv=) at ldso/dlstart.c:147 > > > 147 dls2((void *)base, sp); > > > > > > $ gcc --version > > > gcc (Debian 6.3.0-5) 6.3.0 20170124 > > > > > > Not sure if this is a GCC issue or a musl issue now. > > > > Can you post the crashing libc.so somewhere? Depending on how they're > > building it, the problem could be in various different places. A > > glibc-targeted powerpc* gcc is not suitable for compiling musl, since > > it has various ABI mismatches, but that's probably not what you're > > seeing here even if one was used. > > Sure. You can grab it directly from Debian: > > $ wget http://cdn-fastly.deb.debian.org/debian/pool/main/m/musl/musl_1.1.16-2_ppc64el.deb > > $ dpkg-deb -x musl_1.1.16-2_ppc64el.deb . > > $ lib/powerpc64le-linux-musl/libc.so > [2] 25672 segmentation fault (core dumped) lib/powerpc64le-linux-musl/libc.so Can you do a register dump and a dissassembly dump and around the point that crashes? The Debian package is fully stripped (lacks debug symbols) so it's hard to follow what it's doing, but I didn't see anything obviously wrong. Rich