Bug#591544: libc6: dlopen() does not return when static compilation is used

[Ludovic Rousseau <rousseau@debian.org>]

Package: libc6
Version: 2.11.2-2
Severity: important

The jpilot package ./configure script generate a test program that does
not finish.

A short version of the problematic source code is:

#include <dlfcn.h>

int main ()
{
  void *self = dlopen (0, RTLD_GLOBAL | RTLD_LAZY);

  return 0;
}

And is compiled using:

$ gcc -o conftest -g -Wall   -DHAVE_DLFCN_H  -Wl,--export-dynamic -static conftest.c -ldl
conftest.c: In function ‘main’:
conftest.c:5: warning: unused variable ‘self’
/usr/bin/ld: /tmp/ccToBZZa.o: in function main:conftest.c:5: warning: Using `dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking

The warning may be an indication that something strange is happening.

Then the execution:

$ ./conftest
But never returns and the ./configure never finishes.

[...]
checking whether the gcc linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes
checking whether -lc should be explicitly linked in... no
checking dynamic linker characteristics... GNU/Linux ld.so
checking how to hardcode library paths into programs... immediate
checking for shl_load... no
checking for shl_load in -ldld... no
checking for dlopen... no
checking for dlopen in -ldl... yes
checking whether a program can dlopen itself... yes
checking whether a statically linked program can dlopen itself... 

And the execution is now blocked forever.

I have the problem when using testing/squeeze.
I can't reproduce it by running ./configure on unstable/sid.

In fact I can't recompile the sample code on sid using the same command.
In sid I have:

$ gcc -o conftest -g -Wall   -DHAVE_DLFCN_H  -Wl,--export-dynamic -static conftest.c -ldl
conftest.c: In function ‘main’:
conftest.c:5: warning: unused variable ‘self’
/tmp/ccQplQtT.o: In function `main':
/home/rousseau/conftest.c:5: warning: Using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/bin/ld: dynamic STT_GNU_IFUNC symbol `strcmp' with pointer equality in `/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/libc.a(strcmp.o)' can not be used when making an executable; recompile with -fPIE and relink with -pie
collect2: ld returned 1 exit status


I can do additionnal tests if needed.

Bye

-- System Information:
Debian Release: squeeze/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-5-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages libc6 depends on:
ii  libc-bin                      2.11.2-2   Embedded GNU C Library: Binaries
ii  libgcc1                       1:4.4.4-7  GCC support library

libc6 recommends no packages.

Versions of packages libc6 suggests:
ii  debconf [debconf-2.0]         1.5.33     Debian configuration management sy
pn  glibc-doc                     <none>     (no description available)
ii  locales                       2.11.2-2   Embedded GNU C Library: National L

-- debconf information:
* glibc/upgrade: true
  glibc/disable-screensaver:
  glibc/restart-failed:
* glibc/restart-services: gdm ssh exim4 cups cron atd