[Bug libstdc++/100851] New: Using std::thread on Alpine Linux/musl causes SIGABRT after main when unloading a shared library.

["michaldrozd at protonmail dot ch" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100851

            Bug ID: 100851
           Summary: Using std::thread on Alpine Linux/musl causes SIGABRT
                    after main when unloading a shared library.
           Product: gcc
           Version: 10.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: michaldrozd at protonmail dot ch
  Target Milestone: ---

Created attachment 50901
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50901&action=edit
Code sample to reproduce the issue

The provided sample crashes somewhere after exiting from main with the
following backtrace (this is the best I could get):

        Thread 1 "a.out" received signal SIGABRT, Aborted.
        __restore_sigs (set=set@entry=0x7ffe4a7eac00) at
./arch/x86_64/syscall_arch.h:40
        40      ./arch/x86_64/syscall_arch.h: No such file or directory.
        (gdb) bt
        #0  __restore_sigs (set=set@entry=0x7ffe4a7eac00) at
./arch/x86_64/syscall_arch.h:40
        #1  0x00007f9b8c44750d in raise (sig=sig@entry=6) at
src/signal/raise.c:11
        #2  0x00007f9b8c41df25 in abort () at src/exit/abort.c:11
        #3  0x00007f9b8c22ab53 in __deregister_frame_info_bases () from
/usr/lib/libgcc_s.so.1
        #4  0x00007f9b8c3d9c5e in __do_global_dtors_aux () from
/usr/lib/libpaho-mqtt3cs.so.1
        #5  0x000055c817f69294 in test(void*) ()
        #6  0x00007f9b8c497880 in ?? () from /lib/ld-musl-x86_64.so.1
        #7  0x00007f9b8c497b48 in builtin_tls () from /lib/ld-musl-x86_64.so.1
        #8  0x00007f9b8c3f5d97 in ?? () from /usr/lib/libpaho-mqtt3cs.so.1
        #9  0x0000000000000000 in ?? ()

I'm not sure the problem is isolated to the libpaho library, but this is the
only one I could reproduce this behaviour with (related libpaho issue report:
https://github.com/eclipse/paho.mqtt.c/issues/1110). I've been testing with the
latest libpaho v1.3.9
(https://github.com/eclipse/paho.mqtt.c/releases/tag/v1.3.9), it needs to be
compiled and installed with:
        cmake -DPAHO_WITH_SSL=TRUE -DCMAKE_BUILD_TYPE=Debug
-DCMAKE_INSTALL_PREFIX:PATH=/usr -DCMAKE_INSTALL_LIBDIR=lib .
        make install

Both commenting out the std::thread and replacing it with pthread calls make
this issue go away.

OS: Alpine Linux v3.13
Compiler: gcc (Alpine 10.2.1_pre1)
Musl version: musl-1.2.2