Re: [Python-Dev] Newly Built Python3 Binary Throws Segfault

Are you sure the patch was applied correctly? I was SO sure it would work!

FYI, you tried the patch I attached to the email message, right?

On Fri, Jan 30, 2015 at 12:58 PM, Cyd Haselton <chas...@gmail.com> wrote:

> Update:  I did try the patch after getting it installed correctly, but> I'm still getting a segfault on the newly built binary.> Will post info this afternoon.>> On Fri, Jan 30, 2015 at 12:10 PM, Ryan Gonzalez <rym...@gmail.com> wrote:> > No, it returns NULL if malloc gives it a raw pointer. It unconditionally> > checks the length of the (possibly null) string argument first.> >> > Please try the patch I attached in the last email. It *might* fix the> issue.> > Android has crappy locale handling.> >> > On Fri, Jan 30, 2015 at 12:09 PM, Cyd Haselton <chas...@gmail.com>> wrote:> >>> >>   Unless i'm reading something incorrectly,  _PyMem_RawStrdup is> >> currently returning NULL when given a null pointer.> >>> >> From obmalloc.c> >>> >> _PyMem_RawStrdup(const char *str)> >> {> >>     size_t size;> >> char *copy;> >>     size = strlen(str) + 1;> >>     copy = PyMem_RawMalloc(size);> >>     if (copy == NULL)> >>         return NULL;> >> memcpy(copy, str, size);> >> return copy;> >>           }> >>> >> On Fri, Jan 30, 2015 at 11:56 AM, Ryan Gonzalez <rym...@gmail.com>> wrote:> >> > I seriously doubt the issue is in that file; _PyMem_RawStrdup crashes> >> > when> >> > calling strlen. It's that whatever is calling it is likely asking it> to> >> > duplicate a null pointer. Basically, it's probably the caller's fault.> >> >> >> > You could always try modifying _PyMem_RawStrdup to return NULL when> >> > given a> >> > null pointer and see where it then segfaults.> >> >> >> > On Fri, Jan 30, 2015 at 11:53 AM, Cyd Haselton <chas...@gmail.com>> >> > wrote:> >> >>> >> >> Alternatively, is there a hassle-free way to find out what changed in> >> >> obmalloc.c between 2.7.x and 3.4.x?> >> >>> >> >>> >> >> On Fri, Jan 30, 2015 at 9:29 AM, Cyd Haselton <chas...@gmail.com>> >> >> wrote:> >> >> > There's a related strdup patch for readline.c, mentioned> >> >> > here:http://bugs.python.org/issue21390 and here> >> >> > https://github.com/rave-engine/python3-android/issues/2.> >> >> > There's a patch, but I'm not sure how to modify it for obmalloc.c,> as> >> >> > (I think) the functions all belong to Python...they're all prefixed> >> >> > with _PyXx> >> >> >> >> >> > On Fri, Jan 30, 2015 at 9:05 AM, Cyd Haselton <chas...@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 <rym...@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 <chas...@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 <> rym...@gmail.com>> >> >> >>>> wrote:> >> >> >>>>>> >> >> >>>>>  On Wed, Jan 28, 2015 at 10:43 AM, Guido van Rossum> >> >> >>>>> <gui...@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> >> >> >>>>>> <chas...@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> >> >> >>>>>>> <gui...@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> >> >> >>>>>>>> <chas...@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> >> >> >>>>>>>>>> >> >> >>>>>>>>> Pyth...@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> >> >> >>>>>>  Pyth...@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/> >> >> >> >> > --> > 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/>



-- 
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/