#213 crash glGetError

GLUT (25)

With PyOpenGL 3.0.0 and Python 2.6.2 (on x86),

the following simple file causes a crash:

from OpenGL.GLUT import *

(gdb) run gltest.py
Starting program: /usr/local/bin/python gltest.py
[Thread debugging using libthread_db enabled]
[New Thread 0xb7da28d0 (LWP 1302)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb7da28d0 (LWP 1302)]
0xb7c1b196 in glGetError () from /usr/lib/libGL.so.1
(gdb) where
#0 0xb7c1b196 in glGetError () from /usr/lib/libGL.so.1
#1 0xb7c91f67 in ffi_call_SYSV () at /home/stephanh/DOWNLOAD/Python-2.6.2/Modules/_ctypes/libffi/src/x86/sysv.S:61
#2 0xb7c91da6 in ffi_call (cif=0xbf87d9a8, fn=0xb7c1b190 <glGetError>, rvalue=0x0, avalue=0xbf87da20)
at /home/stephanh/DOWNLOAD/Python-2.6.2/Modules/_ctypes/libffi/src/x86/ffi.c:213
#3 0xb7c8c4aa in _CallProc (pProc=0xb7c1b190 <glGetError>, argtuple=0xb7d6202c, flags=<value optimized out>, argtypes=0x0,
restype=0x86b85fc, checker=0x0) at /home/stephanh/DOWNLOAD/Python-2.6.2/Modules/_ctypes/callproc.c:815
#4 0xb7c83da9 in CFuncPtr_call (self=0x8700304, inargs=0xb7d6202c, kwds=0x0)
at /home/stephanh/DOWNLOAD/Python-2.6.2/Modules/_ctypes/_ctypes.c:3857
#5 0x0805f6ca in PyObject_Call (func=0x8700304, arg=0xb7d6202c, kw=0x0) at Objects/abstract.c:2492
#6 0x080dacfa in PyEval_EvalFrameEx (f=0x87a6444, throwflag=0) at Python/ceval.c:3917
#7 0x080dddc8 in PyEval_EvalCodeEx (co=0x871d068, globals=0x870cdfc, locals=0x0, args=0xb7d507e0, argcount=4, kws=0x0,
kwcount=0, defs=0x871c6d8, defcount=2, closure=0x0) at Python/ceval.c:2968
#8 0x08131fef in function_call (func=0x8713df4, arg=0xb7d507d4, kw=0x0) at Objects/funcobject.c:524
#9 0x0805f6ca in PyObject_Call (func=0x8713df4, arg=0xb7d507d4, kw=0x0) at Objects/abstract.c:2492
#10 0x080665ca in instancemethod_call (func=0x8713df4, arg=0xb7d507d4, kw=0x0) at Objects/classobject.c:2579
#11 0x080640d1 in PyObject_CallFunctionObjArgs (callable=0xb7cd2dec) at Objects/abstract.c:2492
#12 0xb7c83de3 in CFuncPtr_call (self=0x876043c, inargs=0xb7d5232c, kwds=0x0)
at /home/stephanh/DOWNLOAD/Python-2.6.2/Modules/_ctypes/_ctypes.c:3873
#13 0x0805f6ca in PyObject_Call (func=0x876043c, arg=0xb7d5232c, kw=0x0) at Objects/abstract.c:2492
#14 0x080dacfa in PyEval_EvalFrameEx (f=0x86a0f8c, throwflag=0) at Python/ceval.c:3917
#15 0x080dddc8 in PyEval_EvalCodeEx (co=0xb7d8f6e0, globals=0xb7d850b4, locals=0xb7d850b4, args=0x0, argcount=0, kws=0x0,
kwcount=0, defs=0x0, defcount=0, closure=0x0) at Python/ceval.c:2968
#16 0x080ddf27 in PyEval_EvalCode (co=0xb7d8f6e0, globals=0xb7d850b4, locals=0xb7d850b4) at Python/ceval.c:522
#17 0x080fbb01 in PyRun_FileExFlags (fp=0x8653cf8, filename=0xbf87f8f8 "gltest.py", start=257, globals=0xb7d850b4,
locals=0xb7d850b4, closeit=1, flags=0xbf87e718) at Python/pythonrun.c:1335
#18 0x080fbe5a in PyRun_SimpleFileExFlags (fp=0x8653cf8, filename=0xbf87f8f8 "gltest.py", closeit=1, flags=0xbf87e718)
at Python/pythonrun.c:931
#19 0x0805ae42 in Py_Main (argc=1, argv=0xbf87e7e4) at Modules/main.c:599
#20 0x08059f32 in main (argc=-1081615896, argv=0xb7c91da6) at ./Modules/python.c:23


  • Stephan Houben

    Stephan Houben - 2009-05-31

    Hi all,

    Turns out the problem is caused by the implicit call to glGetError()
    caused by glutInitDisplayMode() which is done before a window
    is created.

    Presumably, this means no OpenGL context is created either at this point.
    If I do a glutCreateWindow() before glutInitDisplayMode() everything is fine.

    I am not sure if doing a glGetError before a GL context is created is supposed to be legal.
    If it is, the blame rests on the GL implementation (mesa) but otherwise it is
    bug in PyOpenGL. I think calling glutInitDisplayMode() before glutCreateWindow()
    is ordinarily an expected order.


  • Mike C. Fletcher

    • status: open --> closed-fixed
  • Mike C. Fletcher

    Thanks for the bug report, PyOpenGL 3.0.1 (current head) has fixed the problem with the implicit calling of glGetError, which is no longer safe on Linux platforms.


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