[Bug 490744] Re: cerr crash in dlopen'ed c++ shared object, if linked to some libs

[Václav Šmilauer]

After trying this with gcc 4.4, 4.5, 4.6, I am no longer able to
reproduce this bug, hence marking as Fix Released.

** Changed in: gcc-4.4 (Ubuntu)
       Status: New => Fix Released

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Title:
  cerr crash in dlopen'ed c++ shared object, if linked to some libs

Status in “gcc-4.4” package in Ubuntu:
  Fix Released

Bug description:
  Binary package hint: gcc-4.4

  I have main in c, which dlopens a c++ shared object. Upon calling a
  function (obtained with dlsym) in this c++ lib which uses cerr, there
  is segmentation fault. It happens only if the shared object links to
  some other libraries (like gomp or GL, even if unused). It doesn't
  happen if the main program is compiled with g++ however.

  Here are sources (I will attach those as well) and below is backtrace
  from the debug version of libstdc++.

  I am running fully updated karmic; the same problem occurs at an
  updated hardy and Debian lenny (I don't have access to other systems).

  This is minimal testcase, I have this problem when importing c++
  (boost::python) module into python.

  === main.c ===
  #include<dlfcn.h>
  int main(void){
  	void* handle=dlopen("./libfoo.so",RTLD_NOW);
  	void(*foo)()=(void(*)())dlsym(handle,"foo");
  	foo();
  	return 0;
  }

  === foo.cc ===
  #include<iostream>
  extern "C" {
  	void foo() { std::cerr<<"foo"<<std::endl; }
  }

  === regular run ===
  $ g++ foo.cc -o libfoo.so -fPIC -rdynamic -shared
  $ gcc main.c -o main -ldl
  $ ./main
  foo

  === link libfoo.so to another lib ===
  $ g++ foo.cc -o libfoo.so -fPIC -rdynamic -shared -lgomp # might be GL, perhaps others as well
  $ gcc main.c -o main -ldl
  $ ./main 
  foozsh: segmentation fault (core dumped)  ./main

  === compile main with g++, still link with gomp ===
  $ g++ foo.cc -o libfoo.so -fPIC -rdynamic -shared -lgomp
  $ g++ main.c -o main -ldl
  $ ./main
  foo

  === gdb bt from the crasher ===
  $ g++ foo.cc -o libfoo.so -fPIC -rdynamic -shared -lgomp -g
  $ gcc main.c -o main -ldl -g
  $ LD_LIBRARY_PATH=/usr/lib/debug ./main
  foozsh: segmentation fault (core dumped)  LD_LIBRARY_PATH=/usr/lib/debug ./main
  $ gdb main core

  [ ... ]

  (gdb) bt
  #0  0x00007f81582c9e49 in std::uncaught_exception () at ../../../../src/libstdc++-v3/libsupc++/eh_catch.cc:136
  #1  0x00007f8158294e04 in ~sentry (this=0x7fff3c47bbc0, __in_chrg=<value optimized out>) at /build/buildd/gcc-4.4-4.4.1/build/x86_64-linux-gnu/libstdc++-v3/include/ostream:408
  #2  0x00007f8158295445 in std::__ostream_insert<char, std::char_traits<char> > (__out=..., __s=0x7f81590cf3be "foo", __n=3)
      at /build/buildd/gcc-4.4-4.4.1/build/x86_64-linux-gnu/libstdc++-v3/include/bits/ostream_insert.h:110
  #3  0x00007f815829502e in std::operator<< <std::char_traits<char> > (__out=..., __s=0x7f81590cf3be "foo")
      at /build/buildd/gcc-4.4-4.4.1/build/x86_64-linux-gnu/libstdc++-v3/include/ostream:510
  #4  0x00007f81590cf2e6 in foo () at foo.cc:3
  #5  0x00000000004003a2 in main () at main.c:5

  ProblemType: Bug
  Architecture: amd64
  Date: Tue Dec  1 09:56:47 2009
  DistroRelease: Ubuntu 9.10
  NonfreeKernelModules: fglrx
  Package: libstdc++6 4.4.1-4ubuntu8
  ProcEnviron:
   PATH=(custom, user)
   LANG=cs_CZ.UTF-8
   SHELL=/bin/zsh
  ProcVersionSignature: Ubuntu 2.6.31-16.51~pre2-generic
  SourcePackage: gcc-4.4
  Uname: Linux 2.6.31-16-generic x86_64
  XsessionErrors:
   (gnome-settings-daemon:1984): GLib-CRITICAL **: g_propagate_error: assertion `src != NULL' failed
   (polkit-gnome-authentication-agent-1:2557): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed
   (nautilus:2412): Eel-CRITICAL **: eel_preferences_get_boolean: assertion `preferences_is_initialized ()' failed
   (gnome-panel:2261): Gdk-WARNING **: /build/buildd/gtk+2.0-2.18.3/gdk/x11/gdkdrawable-x11.c:952 drawable is not a pixmap or window

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