[Bug libstdc++/52590] New: std::thread Segmentation fault static linking

[Bug libstdc++/52590] New: std::thread Segmentation fault static linking

[jason at cornsyrup dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52590

             Bug #: 52590
           Summary: std::thread Segmentation fault static linking
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jason@cornsyrup.org


$ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.7.0~rc1-1ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++,go --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin
--enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.7.0 20120302 (prerelease) (Ubuntu/Linaro 4.7.0~rc1-1ubuntu1) 

$ g++ -static -pthread -std=c++0x -o thread thread.cc 

$ ./thread 
pthread_create works
std::thread works
Segmentation fault

$ cat thread.cc 
#include <thread>
#include <iostream>

void *foo1(void *) {
    std::cout << "pthread_create works\n";
    return 0;
}

void foo2() {
    std::cout << "std::thread works\n";
}

int main() {
    {
        pthread_t t;
        pthread_create(&t, 0, foo1, 0);
        void *r;
        pthread_join(t, &r);
    }

    {
        std::thread t(foo2);
        t.join();
    }
    return 0;
}

I was surprised to see that pthreads worked in this case while std::thread did
not. I've also heard that boost::thread works. I'm having a hard time finding
any documentation on whether static linking and std::thread should work
together. Also see
http://stackoverflow.com/questions/7090623/c0x-thread-static-linking-problem

If it is the case that pthreads and std::thread cannot work together with
static linking, then it'd be nice to fail at some point before runtime if that
is possible.

[Bug libstdc++/52590] std::thread Segmentation fault static linking

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52590

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID
           Severity|major                       |normal

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-03-14 20:42:22 UTC ---
> -static 

You need to make sure all of libpthread.a is included, right it does not get
linked that way.

This is not a GCC or glibc bug.

[Bug libstdc++/52590] std::thread Segmentation fault static linking

[jason at cornsyrup dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52590

--- Comment #2 from Jason Toffaletti <jason at cornsyrup dot org> 2012-03-14 21:29:18 UTC ---
(In reply to comment #1)
> > -static 
> 
> You need to make sure all of libpthread.a is included, right it does not get
> linked that way.
> 
> This is not a GCC or glibc bug.

Your comment seems to suggest there is a way, but I can't find it.

g++ -Wl,--whole-archive -static -pthread -std=c++0x -o thread thread.cc

Gives pages of linker errors.
http://sourceware.org/bugzilla/show_bug.cgi?id=10652 suggests glibc and
pthreads just don't work with static linking.

[Bug libstdc++/52590] std::thread Segmentation fault static linking

[jason at cornsyrup dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52590

--- Comment #3 from Jason Toffaletti <jason at cornsyrup dot org> 2012-03-15 04:14:40 UTC ---
$ g++-4.7 -Wl,-M -v -static -pthread -std=c++0x -o thread thread.cc shows all
of libpthread being linked.

With a bit more digging I traced the problem to
/usr/include/c++/4.7.0/x86_64-linux-gnu/bits/gthr-posix.h declaring all of its
symbols with __attribute__((weakref)) even when linking statically. Which
caused the __gthread_* symbols to resolve to zero. I found this for some
background info http://gcc.gnu.org/ml/gcc/2005-10/msg00235.html

This change made my example work:

$ g++ -D_GLIBCXX_GTHREAD_USE_WEAK=0 -static -pthread -std=c++0x -o thread
thread.cc 
$ ./thread 
pthread_create works
std::thread works

However, if I change the code to call std::thread::detach instead of join, then
it crashes again with std::thread::detach being resolved to zero.

Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x0000000000439785 in std::thread::detach() ()
#2  0x0000000000401f52 in main ()

[Bug libstdc++/52590] std::thread Segmentation fault static linking

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52590

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-03-15 07:46:27 UTC ---
The weakref attributes are of course correct, the bug is that you aren't
linking the whole libpthread.a into the app.  On some Linux distributions
libpthread.a
has all the objects linked together with ld -r and therefore this will just
work there, on others you need -Wl,--whole-archive -lpthread
-Wl,--no-whole-archive.
Better yet don't link statically, there are many reasons why it is a bad idea.
http://www.akkadia.org/drepper/no_static_linking.html

[Bug libstdc++/52590] std::thread Segmentation fault static linking

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52590

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lightningdzeyenr at gmail dot com

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
*** Bug 104852 has been marked as a duplicate of this bug. ***

[Bug libstdc++/52590] std::thread Segmentation fault static linking

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52590

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Alexandre Oliva <aoliva@gcc.gnu.org>:

https://gcc.gnu.org/g:21edd841611a97442a6b95e8ec7e91ff8fd3a451

commit r13-6461-g21edd841611a97442a6b95e8ec7e91ff8fd3a451
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Fri Mar 3 15:59:36 2023 -0300

    link pthread_join from std::thread ctor

    Like pthread_create, pthread_join may fail to be statically linked in
    absent strong uses, so add to user code strong references to both when
    std::thread objects are created.


    for  libstdc++-v3/ChangeLog

            PR libstdc++/104852
            PR libstdc++/95989
            PR libstdc++/52590
            * include/bits/std_thread.h (thread::_M_thread_deps): New
            static implicitly-inline member function.
            (std::thread template ctor): Pass it to _M_start_thread.
            * src/c++11/thread.cc (thread::_M_start_thread): Name depend
            parameter, force it live on entry.