[ python-Bugs-1193099 ] Embedded python thread crashes
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Tue Oct 11 05:52:12 CEST 2005
Bugs item #1193099, was opened at 2005-04-30 12:03
Message generated for change (Comment added) made by nnorwitz
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: ugodiggi (ugodiggi)
Assigned to: Nobody/Anonymous (nobody)
Summary: Embedded python thread crashes
Initial Comment:
The following code crashes about 1/3 of the times.
My platform is Python 2.4.1 on WXP (I tried the release
version from the msi and the debug version built by me).
I can reproduce the same behavior on another wxp
system, under python 2.4.
The crash happens (in the python thread) while the main
thread is in Py_Finalize.
I traced the crash to _Py_ForgetReference(op) in
object.c at line 1847, where I have op->_ob_prev == NULL.
The open file seems to be the issue, since if I remove
all the references to the file I cannot get the program
to crash.
Cheers and ciao
Ugo
////////////////////////// TestPyThreads.cpp
//////////////////////////
#include <windows.h> // Sleep
#include "Python.h"
int main()
{
PyEval_InitThreads();
Py_Initialize();
PyGILState_STATE main_restore_state =
PyGILState_UNLOCKED;
PyGILState_Release(main_restore_state);
// start the thread
{
PyGILState_STATE state =
PyGILState_Ensure();
int trash = PyRun_SimpleString(
"import thread\n"
"import time\n"
"def foo():\n"
" f =
open('pippo.out', 'w', 0)\n"
" i = 0;\n"
" while 1:\n"
" f.write('%d\n'%i)\n"
" time.sleep(0.01)\n"
" i += 1\n"
"t =
thread.start_new_thread(foo, ())\n"
);
PyGILState_Release(state);
}
// wait 300 ms
Sleep(300);
PyGILState_Ensure();
Py_Finalize();
return 0;
}
----------------------------------------------------------------------
>Comment By: Neal Norwitz (nnorwitz)
Date: 2005-10-10 20:52
Message:
Logged In: YES
user_id=33168
Perhaps this is caused by different runtime DLLs. Here's
what I googled for: site:mail.python.org windows python
runtime dll crash
See http://python.org/sf/1003535
Can you try to research more and see if you can come up with
anything? (I don't run windows, so I can't test anything.)
Do you get this problem with the version built from
python.org or only with the version you built?
----------------------------------------------------------------------
Comment By: ugodiggi (ugodiggi)
Date: 2005-10-06 00:29
Message:
Logged In: YES
user_id=1269908
Something changed on the computer I'm testing on, and the
crash happens way less often (say 1/10 of the times in debug
mode, and very rarely in Release mode).
The compiler is MSVC7.1 on WXP, using Python 241
This is the stack of the main thread
7ffe0304()
ntdll.dll!77f5b5d4()
kernel32.dll!77e7a683()
msvcr71d.dll!_close_lk(int fh=0x00000003) Line 115 +
0x4a C
msvcr71d.dll!_close(int fh=0x00000003) Line 60 + 0x9
C
msvcr71d.dll!_fclose_lk(_iobuf * str=0x1027c898) Line
127 + 0xc C
msvcr71d.dll!fclose(_iobuf * stream=0x1027c898) Line
58 + 0x9 C
> python24_d.dll!file_dealloc(PyFileObject *
f=0x00919ec8) Line 308 + 0xd C
python24_d.dll!_Py_Dealloc(_object * op=0x00919ec8)
Line 1870 + 0x7 C
python24_d.dll!frame_dealloc(_frame * f=0x00972960)
Line 394 + 0x67 C
python24_d.dll!_Py_Dealloc(_object * op=0x00972960)
Line 1870 + 0x7 C
python24_d.dll!PyThreadState_Clear(_ts *
tstate=0x00892c88) Line 200 + 0x6c C
python24_d.dll!PyInterpreterState_Clear(_is *
interp=0x00894f48) Line 93 + 0x9 C
python24_d.dll!Py_Finalize() Line 401 + 0x9 C
TestPyThreads.exe!main() Line 33 + 0x8 C++
TestPyThreads.exe!mainCRTStartup() Line 259 + 0x19
C
kernel32.dll!77e8141a()
and this is the stack of the other thread (_threadstart)
(the crash is here, where "if (frame->f_exc_type != NULL) "
gets called with frame == NULL)
> python24_d.dll!reset_exc_info(_ts * tstate=0x00892c88)
Line 2861 + 0x3 C
python24_d.dll!PyEval_EvalFrame(_frame *
f=0x00972960) Line 2490 + 0x9 C
python24_d.dll!PyEval_EvalCodeEx(PyCodeObject *
co=0x00943ad0, _object * globals=0x008e3230, _object *
locals=0x00000000, _object * * args=0x008c104c, int
argcount=0x00000000, _object * * kws=0x00000000, int
kwcount=0x00000000, _object * * defs=0x00000000, int
defcount=0x00000000, _object * closure=0x00000000) Line
2730 + 0x9 C
python24_d.dll!function_call(_object * func=0x009431f0,
_object * arg=0x008c1038, _object * kw=0x00000000) Line
553 + 0x40 C
python24_d.dll!PyObject_Call(_object *
func=0x009431f0, _object * arg=0x008c1038, _object *
kw=0x00000000) Line 1751 + 0xf C
python24_d.dll!PyEval_CallObjectWithKeywords(_object
* func=0x009431f0, _object * arg=0x008c1038, _object *
kw=0x00000000) Line 3419 + 0x11 C
python24_d.dll!t_bootstrap(void * boot_raw=0x008c8148)
Line 433 + 0x1a C
python24_d.dll!bootstrap(void * call=0x0012f694) Line
166 + 0x7 C
msvcr71d.dll!_threadstart(void * ptd=0x009101a0) Line
196 + 0xd C
kernel32.dll!77e7d28e()
as you can see, the crash is also happening at a different
place than what I had observed before, but I cannot find the
stack that I had in that case.
----------------------------------------------------------------------
Comment By: ugodiggi (ugodiggi)
Date: 2005-10-05 11:39
Message:
Logged In: YES
user_id=1269908
I would guess that the problem is going to be windows
specific?
I tested similar problem on both the debug and release build,
and I did try to get some comment on comp.lang.python
i.e.
http://mail.python.org/pipermail/python-list/2005-
April/278404.html
my comment on the debugging was:
> The crash happens while the main thread is in Py_Finalize.
> I traced the crash to _Py_ForgetReference(op) in object.c
at line 1847,
> where I have op->_ob_prev == NULL.
I did not look at the python code long enough to follow it.
I will try to reproduce tonight and send out the stack - for
whatever reason I'm not finding it any longer.
----------------------------------------------------------------------
Comment By: Neal Norwitz (nnorwitz)
Date: 2005-10-03 22:37
Message:
Logged In: YES
user_id=33168
I can't reproduce on gentoo linux (amd64) with a debug
build. I played with different values for sleep. BTW, it
would be better if you attached the code as a file, since
formatting is lost.
Can you try to debug this problem?
Can you attach info from the debugger?
----------------------------------------------------------------------
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