[Python-Dev] Newly Built Python3 Binary Throws Segfault
Ryan Gonzalez
rymg19 at gmail.com
Fri Jan 30 20:00:05 CET 2015
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 <chaselton at 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 <rymg19 at 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 <chaselton at 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 <rymg19 at 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 <chaselton at 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 <chaselton at 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 <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/
> >
> >
> >
> >
> > --
> > 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/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-dev/attachments/20150130/0b7408aa/attachment.html>
More information about the Python-Dev
mailing list