[Python-Dev] Newly Built Python3 Binary Throws Segfault

Fri Jan 30 18:52:41 CET 2015

Is it possible at all to get a stack trace of the crash using gdb? Try the
steps here <http://stackoverflow.com/a/10539883/2097780>.

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/
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