How to find cause for Python/Pythonwin crash only on Dual Core Machines ?

[robert]

There is a strange freeze/crash only on dual core machines:

I have a python app (Python 2.3.5 /Pythonwin build 203 / Windows) 
running with no stability problems on normal machines (Or a crash is so 
rare, that absolutely nobody obverses it, though the overall majority of 
users uses single core machines). Threads, network & pythonwin/win32ui 
all in use.

Yet, from 3 users, _all_ using a Dual Processor System (XEON, amd x2 
3800+) computer, I have reports, that the application freezes hard 
and/or crashes with a kind of random stack dump (operating system). I 
cannot experiment with those machines.

I found no hints other than:

http://groups.google.de/group/comp.lang.python/browse_frm/thread/64ca033e1a7f6c61/719b147e870bd5e6

http://sourceforge.net/tracker/?group_id=5470&atid=105470&func=detail&aid=480325

.. both discussions remaining in uncertainty.

Are there (known) problems with Python/Pythonwin specific for dual 
core's  (py2.3.5 / pywin203) ?

What could I do to find the problem?

Robert


--------------

PS: there is very little C extension-code (SWIG) involved, yet I looked 
over that so often, I guess its save:


//

#include "stdafx.h"
#include "commctrl.h"
#include "ext.h"

BOOL APIENTRY DllMain( HANDLE hModule,
                        DWORD  ul_reason_for_call,
                        LPVOID lpReserved
					 )
{
     return TRUE;
}

class CAllowThreads {
public:
	PyThreadState *_save; \
	CAllowThreads() {
			_save = PyEval_SaveThread();
	}
	~CAllowThreads() {
		PyEval_RestoreThread(_save);
	}
};

PyObject* PyListView_GetSubItemRect(
     HWND hwndLV,
     int iItem,
     int iSubItem,
     int code
//    LPRECT lpRect
)
{
	RECT r;
	{
	  CAllowThreads _t;
	  ListView_GetSubItemRect(
		hwndLV,
		iItem,
		iSubItem,
		code,
		&r );
	}
	return Py_BuildValue("iiii", r.left,r.top,r.right,r.bottom);

}

int GetStringAddr(const char* s) {
	return (int)s;
}

int PlaySoundResource(int resid, HMODULE hmod)
{
	CAllowThreads _t;
	return PlaySound(MAKEINTRESOURCE(resid), hmod, SND_RESOURCE);
}

int PlaySoundFile(const char* fname, int flag)
{
	CAllowThreads _t;
	return PlaySound(fname, NULL, flag);
}

PyObject* py_ToolTipRelayMsg(  PyObject* self, PyObject* args )
{
	MSG msg;
	HWND hwTT;
     if(!PyArg_ParseTuple(args,"i(iiiii(ii)):ToolTipRelayMsg",
						 &hwTT,
 
&msg.hwnd,&msg.message,&msg.wParam,&msg.lParam,&msg.time,
                          &msg.pt, ((int*)&msg.pt)+1) )
		return NULL;

	
	{
	  CAllowThreads _t;
	  SendMessage(hwTT,TTM_RELAYEVENT,0,(LPARAM)&msg);
	}

	Py_INCREF( Py_None );
	return Py_None;
}

---

"GetStringAddress" is used only once like this (leades to correct NUL 
termination I think):
 
self.sb.SendMessage(commctrl.SB_SETTEXT,iPane,extension.GetStringAddr(text))

--- swig:
static PyObject *_wrap_GetStringAddr(PyObject *self, PyObject *args) {
     PyObject *resultobj;
     char *arg0 ;
     int result ;

     if(!PyArg_ParseTuple(args,(char *)"s:GetStringAddr",&arg0)) return 
NULL;
     result = (int )GetStringAddr((char const *)arg0);
     resultobj = PyInt_FromLong((long)result);
     return resultobj;
}