[Stackless] Segmentation fault when running example wsgi app in linux/win

Kristján Valur Jónsson kristjan at ccpgames.com
Thu Mar 11 17:46:55 CET 2010


During finalize, orphaned tasklets may be killed.  And for them to be killed, they have to be woken up.
Something is breaking during this process.  gc is very dangerous territory.
I have seen this too but not been able to put my finger on it exactly.
K

> -----Original Message-----
> From: stackless-bounces at stackless.com [mailto:stackless-
> bounces at stackless.com] On Behalf Of Jeff Senn
> Sent: 11. mars 2010 13:49
> To: The Stackless Python Mailing List
> Subject: Re: [Stackless] Segmentation fault when running example wsgi
> app in linux/win
> 
> I had this problem too (embedding Python in a completely different way
> and on OS/X),
> that is: a crash in GC during Py_Finalize.  I spent just a bit of time
> looking
> but didn't resolve much -- my (not very satisfying) solution was *not*
> to call
> Py_Finalize since my program was exiting anyway.
> 
> I seem to recall it was "worse" on a 64-bit compile...
> Håkan, do you have the same problem with a 32-bit compile?
> maybe that's a clue... (or a red herring...)
> 
> Sorry, not much light shedding, let me know if you figure it out...
> 
> On Mar 11, 2010, at 4:55 AM, Håkan Larsson wrote:
> 
> > Hello all,
> >
> > I have been trying out the wsgi server with the app_sessionless
> example downloaded from the google stacklessexamples page and i keep
> getting a assertion and segmentation fault. I have browsed through the
> mailing list archives and there seems to be a similar error posted
> about a year ago. http://www.stackless.com/pipermail/stackless/2009-
> February/003910.html
> >
> > I have the same symptoms as jtunney describes. Works great when you
> do a single request in your web browser but when you stress it a bit
> the server simply exits. When running this with a debug version of
> python under windows i also can see a assertion before the server
> exits.  When stressing it even further under windows i get a
> segmentation fault.
> > Assertion failed: stack_pointer != NULL, file ..\Python\ceval.c, line
> 914.
> >
> > This assertion/crash only happens when the clients are about to
> disconnect. To reproduce this i used jmeter, 10 looping threads doing a
> request against /. When starting the test i can see 10 "Accepted
> connection" print outs and the server serves request. But when i shut
> down the threads a assertion/segmentation fault occures.
> >
> > I have also been able to reproduce this under linux and there i get a
> segmentation fault right away.
> > I have attached some output from gdb, one with standard optimizations
> and one with the flag turned to -O0 for more information.
> >
> > I am running the following setup.
> >
> > Windows:
> > Win 7 x64, (same thing on Vista 64)
> >
> > Linux:
> > Redhat 5 x64
> > Python 2.6.4 Stackless 3.1b3 060516 (release26-maint:78823M, Mar 11
> 2010, 10:10:31)
> > [GCC 4.1.2 20080704 (Red Hat 4.1.2-46)] on linux2
> >
> > python2.6: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV),
> for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for
> GNU/Linux 2.6.9, not stripped
> >
> > Perhaps someone can help shed some light on this one.
> >
> > /Håkan
> >
> > <debug 00.txt><debug
> 03.txt>_______________________________________________
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> 
> 
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