From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnout Vandecappelle Date: Thu, 10 Sep 2015 10:26:36 +0200 Subject: [Buildroot] problem with stack protection, threads and static binaries In-Reply-To: <1441871700.4298.49.camel@fahlgren-laptop> References: <1441871700.4298.49.camel@fahlgren-laptop> Message-ID: <55F13EBC.9060100@mind.be> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net On 10-09-15 09:55, Daniel Fahlgren wrote: > Hi, > > I've encountered a problem when enabling stack protection > (BR2_ENABLE_SSP) in combination with static binaries that uses threads. > The problem is that during start up the program gets a segfault in > __pthread_initialize_minimal_internal(), and I think this might be the > same issue as described in [1]. > > Investigation shows that the offending instruction is a: > > mov %fs:0x28,%rax > > where %fs is 0x00. The reason for that is that the pthread library is > compiled with stack protection but __pthread_initialize_minimal_internal > is called before __libc_setup_tls in static binaries. This sounds like a uClibc issue. Could you verify by testing with uClibc 0.9.33 and/or musl and/or glibc? And then take it to the uClibc-ng mailing list: http://mailman.uclibc-ng.org/cgi-bin/mailman/listinfo/devel/ Just to be sure, putting Waldemar in Cc. > > I have created an ugly patch to verify my hypothesis. With that patch > the test program works, but what is the proper way to solve this issue? > > Attached files (also at https://www.acc.umu.se/~guru/buildroot/) > > add_broken_package.patch - add a test package to buildroot > pthread-broken-1.0.0.tar.gz - the test package > buildroot.config - buildroot config to use > static-pthread.patch - my proof-of-concept patch Wow, great bug information! But in the future, please use a defconfig instead of a full config to reduce the list load. Regards, Arnout > > Best regards, > Daniel Fahlgren > > 1: > http://lists.busybox.net/pipermail/buildroot/2014-February/088561.html > > > > _______________________________________________ > buildroot mailing list > buildroot at busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot > -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286500 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: 7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF