[Python-Dev] Newly Built Python3 Binary Throws Segfault

Cyd Haselton chaselton at gmail.com
Fri Jan 30 19:00:32 CET 2015 

I don't have gdb on device; does the following tell you where Python's
strdup is called?

>> _PyMem_RawStrdup
>> /bld/python/Python-3.4.2/Objects/obmalloc.c:323

On Fri, Jan 30, 2015 at 11:52 AM, Ryan Gonzalez <rymg19 at gmail.com> wrote:
> Is it possible at all to get a stack trace of the crash using gdb? Try the
> steps here.
>
> That way we can see where Python's own strdup function is getting called.
>
> On Fri, Jan 30, 2015 at 9:05 AM, Cyd Haselton <chaselton at gmail.com> wrote:
>>
>> Absolutely.  Good thing I have addr2line on device
>>
>> /bld/python/Python-3.4.2 $ addr2line -C -f -e /lib/libpython3.4m.so.1.0
>> 0008bbc8
>> _PyMem_RawStrdup
>> /bld/python/Python-3.4.2/Objects/obmalloc.c:323
>> /bld/python/Python-3.4.2 $
>>
>>
>>
>> On Thu, Jan 29, 2015 at 8:26 PM, Ryan <rymg19 at gmail.com> wrote:
>> > Could you try the steps at http://stackoverflow.com/a/11369475/2097780?
>> > They
>> > allow you to get a better idea of where libc is crashing.
>> >
>> > Cyd Haselton <chaselton at gmail.com> wrote:
>> >>
>> >> Managed to get this out of logcat:
>> >> F(11914) Fatal signal 11 (SIGSEGV) at 0x00000000 (code=1), thread
>> >> 11914 (python)  (libc)
>> >>
>> >> [ 01-29 19:30:55.855 23373:23373 F/libc     ]
>> >> Fatal signal 11 (SIGSEGV) at 0x00000000 (code=1), thread 23373 (python)
>> >>
>> >> Less detail than strace but it seems to be that python is segfaulting
>> >> libc...
>> >>
>> >> On Wed, Jan 28, 2015 at 11:23 AM, Ryan Gonzalez <rymg19 at gmail.com>
>> >> wrote:
>> >>>
>> >>>  On Wed, Jan 28, 2015 at 10:43 AM, Guido van Rossum <guido at python.org>
>> >>> wrote:
>> >>>>
>> >>>>
>> >>>>  What I see in the strace:
>> >>>>
>> >>>>  ... load libpython3.4m.so.1.0
>> >>>>  ... load libm
>> >>>>  ... open /dev/__properties__ and do something to it
>> >>>> (what?)
>> >>>>  ... get current time
>> >>>>  ... allocate memory
>> >>>>  ... getuid
>> >>>>  ... segfault
>> >>>>
>> >>>>  That's not a lot to go on, but it doesn't look as if it has started
>> >>>> to
>> >>>>  load modules yet.
>> >>>>
>> >>>>  Does /dev/__properties__ ring a bell? Not to me.
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> https://android.googlesource.com/platform/system/core/+/tools_r22/init/property_service.c
>> >>>  is the code that works with that file.
>> >>>
>> >>>  This explains it a bit (slides 24-29). Looks like something to do
>> >>> with
>> >>>  interprocess communication. Likely has nothing to do with Python
>> >>> itself.
>> >>>
>> >>>  Maybe this would be useful?
>> >>>
>> >>>>
>> >>>>  That stack trace would be really helpful.
>> >>>>
>> >>>>  On Wed, Jan 28, 2015 at 8:34 AM, Cyd Haselton <chaselton at gmail.com>
>> >>>> wrote:
>> >>>>>
>> >>>>>
>> >>>>>  Apologies...I'm not sure what a stack track is, but I do have the
>> >>>>>  strace.  Nearest I can tell, it happens due to an open call, though
>> >>>>> I
>> >>>>>  am probably wrong.
>> >>>>>  Attaching the strace output to this email.  I'm going to head back
>> >>>>> to
>> >>>>>  the documentation and to back out of some Android-related changes
>> >>>>> in
>> >>>>>  _localemodule.c
>> >>>>>
>> >>>>>  On Wed, Jan 28, 2015 at 9:43 AM, Guido van Rossum
>> >>>>> <guido at python.org>
>> >>>>>  wrote:
>> >>>>>>
>> >>>>>>  There could be a million differences relevant (unicode, ints,
>> >>>>>> ...).
>> >>>>>>  Perhaps
>> >>>>>>  the importlib bootstrap is failing. Perhaps the dynamic loading
>> >>>>>> code
>> >>>>>>  changed. Did you get a stack track? (IIRC strace shows a syscall
>> >>>>>> trace
>> >>>>>>  --
>> >>>>>>  also useful, but doesn't tell you precisely how
>> >>>>>> it segfaulted.)
>> >>>>>>
>> >>>>>>  On Wed, Jan 28, 2015 at 6:43 AM, Cyd Haselton
>> >>>>>> <chaselton at gmail.com>
>> >>>>>>  wrote:
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>  All,
>> >>>>>>>  I recently ditched my attempts to port Python 2.7.8 to Android in
>> >>>>>>>  favor of Python 3.4.2.  Unfortunately, after using the same
>> >>>>>>> configure
>> >>>>>>>  options in the same environment, and modifying the setup.py as
>> >>>>>>> needed,
>> >>>>>>>  the newly built binary throws a segfault when the
>> >>>>>>> generate-posix-vars
>> >>>>>>>  portion of the build is reached...and when it is run as well
>> >>>>>>> (i.e.
>> >>>>>>>  ./python --help, ./python -E -S -m sysconfig, or similar)
>> >>>>>>>
>> >>>>>>>  I took a strace of ./python, however I'm a bit lost when
>> >>>>>>> reviewing
>> >>>>>>> it.
>> >>>>>>>  Any ideas as to what may be going on...i.e. why Python 2.7 works
>> >>>>>>> but
>> >>>>>>>  3.x throws a segfault?
>> >>>>>>>
>> >>>>>>>  Thanks in advance,
>> >>>>>>>  Cyd
>> >>>>>>> ________________________________
>> >>>>>>>
>> >>>>>>>  Python-Dev mailing list
>> >>>>>>>
>> >>>>>>> Python-Dev at python.org
>> >>>>>>>  https://mail.python.org/mailman/listinfo/python-dev
>> >>>>>>>  Unsubscribe:
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> https://mail.python.org/mailman/options/python-dev/guido%40python.org
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>>  --
>> >>>>>>  --Guido van Rossum (python.org/~guido)
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>  --
>> >>>>  --Guido van Rossum (python.org/~guido)
>> >>>>
>> >>>> ________________________________
>> >>>>
>> >>>>  Python-Dev mailing list
>> >>>>  Python-Dev at python.org
>> >>>>  https://mail.python.org/mailman/listinfo/python-dev
>> >>>>  Unsubscribe:
>> >>>>
>> >>>> https://mail.python.org/mailman/options/python-dev/rymg19%40gmail.com
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>  --
>> >>>  Ryan
>> >>>  If anybody ever asks me why I prefer C++ to C, my answer will be
>> >>> simple:
>> >>>  "It's becauseslejfp23(@#Q*(E*EIdc-SEGFAULT. Wait, I don't think that
>> >>> was
>> >>>  nul-terminated."
>> >>>  Personal reality distortion fields are immune to contradictory
>> >>> evidence.
>> >>> -
>> >>>  srean
>> >>>  Check out my website: http://kirbyfan64.github.io/
>> >
>> >
>> > --
>> > Sent from my Android phone with K-9 Mail. Please excuse my brevity.
>> > Check out my website: http://kirbyfan64.github.io/
>
>
>
>
> --
> Ryan
> If anybody ever asks me why I prefer C++ to C, my answer will be simple:
> "It's becauseslejfp23(@#Q*(E*EIdc-SEGFAULT. Wait, I don't think that was
> nul-terminated."
> Personal reality distortion fields are immune to contradictory evidence. -
> srean
> Check out my website: http://kirbyfan64.github.io/

More information about the Python-Dev mailing list