Comment 9 for bug 893605

This shows up as a crash in gnucash with glibc-2.15 on Precise Pangolin.
https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/893605

Confirmed present in current glibc git trunk.

Test:

/// --- cut --- foo.c ---
int foo () { return bar (); }

/// --- cut --- bar.c ---
int bar () { return 42; }

/// --- cut --- t.c ---
#include <stdio.h>
#include <dlfcn.h>

int main ()
{
  void *h = dlopen ("./foo.so", RTLD_LAZY|RTLD_GLOBAL);
  void *p = dlsym (h, "bar");

  printf ("h = %p, p = %p\n", h, p);

  dlclose (h);

  h = dlopen ("./foo.so", RTLD_LAZY|RTLD_GLOBAL);
  p = dlsym (h, "bar");
  printf ("h = %p, p = %p\n", h, p);

  return 0;
}

gcc -fPIC -shared -o bar.so bar.c &&
gcc -fPIC -shared -o foo.so foo.c ./bar.so &&
gcc t.c ./foo.so ./bar.so -ldl

valgrind ./a.out # no errors with glibc-2.11

==16605== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==16605== Using Valgrind-3.8.0.SVN and LibVEX; rerun with -h for copyright info
==16605== Command: ./a.out
==16605==
h = 0x4023b78, p = 0x503759c
==16605== Invalid read of size 8
==16605== at 0x40093F6: do_lookup_x (/tmp/glibc-git/elf/dl-lookup.c:98)
==16605== by 0x4009E4A: _dl_lookup_symbol_x (/tmp/glibc-git/elf/dl-lookup.c:739)
==16605== by 0x5551305: do_sym (/tmp/glibc-git/elf/dl-sym.c:178)
==16605== by 0x523A043: dlsym_doit (/tmp/glibc-git/dlfcn/dlsym.c:51)
==16605== by 0x400E685: _dl_catch_error (/tmp/glibc-git/elf/dl-error.c:178)
==16605== by 0x523A4DB: _dlerror_run (/tmp/glibc-git/dlfcn/dlerror.c:164)
==16605== by 0x523A099: dlsym (/tmp/glibc-git/dlfcn/dlsym.c:71)
==16605== by 0x400806: main (in /tmp/bug/a.out)
==16605== Address 0x57e6098 is 40 bytes inside a block of size 72 free'd
==16605== at 0x4C2C0EB: free (/valgrind-test/coregrind/m_replacemalloc/vg_replace_malloc.c:426)
==16605== by 0x4011D21: _dl_scope_free (/tmp/glibc-git/elf/dl-scope.c:32)
==16605== by 0x4013446: _dl_close_worker (/tmp/glibc-git/elf/dl-close.c:130)
==16605== by 0x401407B: _dl_close (/tmp/glibc-git/elf/dl-close.c:779)
==16605== by 0x400E685: _dl_catch_error (/tmp/glibc-git/elf/dl-error.c:178)
==16605== by 0x523A4DB: _dlerror_run (/tmp/glibc-git/dlfcn/dlerror.c:164)
==16605== by 0x523A00E: dlclose (/tmp/glibc-git/dlfcn/dlclose.c:48)
==16605== by 0x4007DF: main (in /tmp/bug/a.out)
==16605==
h = 0x4023b78, p = 0x503759c
==16605==
==16605== HEAP SUMMARY:
==16605== in use at exit: 0 bytes in 0 blocks
==16605== total heap usage: 2 allocs, 2 frees, 200 bytes allocated
==16605==
==16605== All heap blocks were freed -- no leaks are possible
==16605==
==16605== For counts of detected and suppressed errors, rerun with: -v
==16605== ERROR SUMMARY: 2 errors from 1 contexts (suppressed: 2 from 2)

The bug may have been introduced here:

commit 4bff6e0175ed195871f4e01cc4c4c33274b8f6e3
Author: Andreas Schwab <email address hidden>
Date: Fri Feb 25 20:49:48 2011 -0500

    Fix memory leak in dlopen with RTLD_NOLOAD.