[ python-Bugs-1441884 ] A (treaded) Python crash only on dual core machines

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Bugs item #1441884, was opened at 2006-03-02 18:17
Message generated for change (Comment added) made by loewis
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Category: Threads
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Robert Kiendl (kxroberto)
Assigned to: Nobody/Anonymous (nobody)
Summary: A (treaded) Python crash only on dual core machines

Initial Comment:
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
specifically 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;
} 

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

>Comment By: Martin v. Löwis (loewis)
Date: 2006-03-03 18:40

Message:
Logged In: YES 
user_id=21627

You don't provide complete source code for anybody to try to reproduce this 
problem. My guess is that you are calling into the Python runtime without 
holding the global interpreter lock. This can easily create all sorts of 
problems.

Never release the GIL unless you are absolutely certain that no Python code 
will 
be executed; neither directly nor indirectly. Don't invoke Python API in a 
thread 
(e.g. while processing a Windows message) without acquiring the GIL first.

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

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