[mod_python] Help about apache mod_python Segmentation fault

auther_bin auther_bin at 21cn.com
Mon Mar 3 02:18:13 EST 2008

Hi Graham Dumpleton,

¡¡¡¡I comiling all the libs and mod_python with "-g", and run gdb of httpd, but could not catch the wro
ng piont correctly, here is some messages:

=============== GDB run with -X ===============================
# gdb httpd 
argc=2 argv=0xbffff9b4 envp=0xbffff9c0
ELF header=0x40000000
First Dynamic section entry=0x40009efc
transfering control to application @ 0x8070360
GNU gdb 5.3
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This GDB was configured as "i686-pc-linux-gnu"...
(gdb) run -X
Starting program: /usr/local/apache2/bin/httpd -X
argc=3 argv=0xbfffe574 envp=0xbfffe584
ELF header=0x40000000
[New Thread 1024 (LWP 8609)]
transfering control to application @ 0x8065250
JJJJJJ apr_app_initialize(2, /usr/local/apache2/bin/httpd, -X, (null))
JJJJJJJ in apr_initialize srclib/apr/misc/unix
JJJJJJJ in before apr_pool_create srclib/apr/misc/unix
JJJJJJJ in before apr_pool_tag srclib/apr/misc/unix
httpd: apr_sockaddr_info_get() failed for localhost.localdomain
httpd: Could not reliably determine the server's fully qualified domain name, using for ServerName
												<----- give a web requirement here.
JJJJJJJJJJJJJJJ python_connection
JJJJJJJJJ PythonPostReadRequestHandler
JJJJJJJJ PythonInitHandler -> python_handler
JJJJJJJJ 81e604c[27]
Cannot find user-level thread for LWP 8609: generic error
(gdb) where
Cannot find thread 1024: generic error
======================= GDB could not working any more here ====================
BTW, the lines begains with "JJJJ" is the printf gives, where I inputed into the sourcecode
of apache and mod_python.

if I run httpd -X without gdb, the httpd gives:
JJJJJJJJ 81e605c[27]
Segmentation fault

after times of work, I think is it the problem lies on the module Load process?
for if i rem the config line in httpd.conf "LoadModule python_module modules/mod_python.so", the httpd could works well.

======= 2008-02-27 wrote: =======

>On 27/02/2008, auther_bin <auther_bin at 21cn.com> wrote:
>> Dear friends,
>>         When I compiling the apache python mod_python and install it into my uClibc envirentment, but when I
>>  runing httpd -X, send a very little request with index.html it crashed. after some debuging work, I find there should be something wrong in mod_python.c line(about 1561) which looks like:
>>  --------------------------------- with my debug printing :) ------------------------
>>  printf("JJJJJJJJ %s -> python_handler\n", phase);
>>  printf("JJJJJJJJ %x[%d]\n", &req->per_dir_config, (&python_module)->module_index);
>>     /* get configuration */
>>     conf = (py_config *) ap_get_module_config(req->per_dir_config,
>>                                                   &python_module);
>>  printf("JJJJJJJJ a %s conf=%x -> python_handler\n", phase,conf);
>>  .............
>>  ------------------------------ end source --------------------------------------
>>  I guess that, there should be a regester error in it. with some debug message I print:
>>  ------------- printing -------------------------------
>>  JJJJJJJJJ PythonPostReadRequestHandler
>>  JJJJJJJJ PythonInitHandler -> python_handler
>>  JJJJJJJJ 820a544[29]
>>  Segmentation fault
>>  ------------- end printing ---------------------------
>>  any advices pls?
>Unfortunately that doesn't help much.
>You need a stack trace to show the true location in code.
>Use procedure documented in section 'Debugging Crashes With GDB' of:
>  http://code.google.com/p/modwsgi/wiki/DebuggingTechniques
>to run up httpd inside of gdb and get a stack trace of where crash is occurring.
>This documentation is for mod_wgsi, but same procedure used for mod_python.
>There is a similar procedure documented on Apache site, but can't
>remember where.
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