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

Håkan Larsson hakan at esn.me
Thu Mar 11 10:55:50 CET 2010

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.

Win 7 x64, (same thing on Vista 64)

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.


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