[Bug libstdc++/52604] mt allocator crashes on multi-threaded

["laurent.alfonsi at st dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52604

--- Comment #1 from Laurent Aflonsi <laurent.alfonsi at st dot com> 2012-03-16 15:25:23 UTC ---
I would propose to fix as follows :
- Set the _M_Key=NULL when calling the freelist desctuctor.
- Testing the NULL Key before using it with setspecific.
see patch below :

===================================================================
--- libstdc++-v3/src/mt_allocator.cc    (revision 2486)
+++ libstdc++-v3/src/mt_allocator.cc    (working copy)
@@ -47,6 +47,7 @@
       if (_M_thread_freelist_array)
        {
          __gthread_key_delete(_M_key);
+         _M_key = NULL;
          ::operator delete(static_cast<void*>(_M_thread_freelist_array));
        }
     }
@@ -639,7 +640,8 @@
                }
            }

-           __gthread_setspecific(freelist._M_key, (void*)_M_id);
+           if (freelist._M_key)
+               __gthread_setspecific(freelist._M_key, (void*)_M_id);
          }
        return _M_id >= _M_options._M_max_threads ? 0 : _M_id;
       }
===================================================================

Let me know what you think

Thanks very much
Laurent Alfonsi