[issue29347] Python 2.7.8 is crashing while creating weakref for a given object.

[Saida Dhanavath]

Saida Dhanavath added the comment:

Hi Christian Heimes,


Please ignore typos in the previous post. I have written some code to simulate and test PyWeakReference struct instantiation and then hit segfault based on the flag passed to C code. Here I am trying to execute some of the operations from new_weakref and dealloc_weakref of Objects/weakrefobject.c to show that new instance of PyWeakReference is not initialized properly and results in segfault. Have also checked python 3.6.0 source and I do not see any change in weakref alloc and dealloc routines of 2.7.8 and 3.6.0 versions. Have run test code on 2.7.8, 2.7.12+, 3.4m and 3.5m interpreters and got segfault in all runs.


Please find the sample output as given below.

ubuntu at ubuntu1610saida:~/weakref$ make build PYVERSION=2.7
swig -python weakref_crash.i
gcc -w -fpic -c weakref_crash.c weakref_crash_wrap.c -I/usr/include/python2.7
gcc -shared weakref_crash.o weakref_crash_wrap.o -o _pyweakref_crash.so -L/usr/lib/python2.7 -lpython2.7

ubuntu at ubuntu1610saida:~/weakref$ python test.py 0 0
2.7.12+ (default, Sep 17 2016, 12:08:02) 
[GCC 6.2.0 20160914]
0
0

ubuntu at ubuntu1610saida:~/weakref$ python test.py 0 1
2.7.12+ (default, Sep 17 2016, 12:08:02) 
[GCC 6.2.0 20160914]
0
0

ubuntu at ubuntu1610saida:~/weakref$ python test.py 1 0
2.7.12+ (default, Sep 17 2016, 12:08:02) 
[GCC 6.2.0 20160914]
1010101
1010101

ubuntu at ubuntu1610saida:~/weakref$ python test.py 1 1
2.7.12+ (default, Sep 17 2016, 12:08:02) 
[GCC 6.2.0 20160914]
1010101
1010101
Segmentation fault (core dumped)

ubuntu at ubuntu1610saida:~/weakref$ make clean
rm -f *.so *.o *crash.py *.pyc *crash_wrap.c

ubuntu at ubuntu1610saida:~/weakref$ make build PYVERSION=3.5m
swig -python weakref_crash.i
gcc -w -fpic -c weakref_crash.c weakref_crash_wrap.c -I/usr/include/python3.5m
gcc -shared weakref_crash.o weakref_crash_wrap.o -o _pyweakref_crash.so -L/usr/lib/python3.5m -lpython3.5m
ubuntu at ubuntu1610saida:~/weakref$ python3.5m test.py 0 0
3.5.2+ (default, Sep 22 2016, 12:18:14) 
[GCC 6.2.0 20160927]
0
0
ubuntu at ubuntu1610saida:~/weakref$ python3.5m test.py 0 1
3.5.2+ (default, Sep 22 2016, 12:18:14) 
[GCC 6.2.0 20160927]
0
0
ubuntu at ubuntu1610saida:~/weakref$ python3.5m test.py 1 0
3.5.2+ (default, Sep 22 2016, 12:18:14) 
[GCC 6.2.0 20160927]
1010101
101
ubuntu at ubuntu1610saida:~/weakref$ python3.5m test.py 1 1
3.5.2+ (default, Sep 22 2016, 12:18:14) 
[GCC 6.2.0 20160927]
1010101
101
Segmentation fault (core dumped)

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue29347>
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