[mod_python] Help about apache mod_python Segmentation fault

Graham Dumpleton graham.dumpleton at gmail.com
Mon Mar 3 04:18:18 EST 2008


In gdb, instead of 'where', try:

  thread apply all bt

in case gdb isn't throwing you into the correct thread context.

BTW, does the Python on the environment that crashes provide a shared
library? For what I am talking about see:

  http://code.google.com/p/modwsgi/wiki/InstallationIssues

This is documentation from mod_wsgi but same problems apply to mod_python.

Graham

On 03/03/2008, auther_bin <auther_bin at 21cn.com> wrote:
>
>
> Hi Graham Dumpleton,
>
> And, when I debug in RedHat9 and my embeded
> envirenment, the main process goes
> different!?
>
> in Redhat9, run like:
>
>
> (gdb) b main
> Breakpoint 1 at 0x8067a40: file main.c, line 438.
> (gdb) run -X
> Starting program: /usr/local/apache2/bin/httpd -X
> [New Thread 1076592288 (LWP 1049)]
> [Switching to Thread 1076592288 (LWP 1049)]
>
> Breakpoint 1, main (argc=134642240, argv=0x2) at main.c:438
> 438     {
> (gdb) n
> 272         stat = apr_app_initialize(argc, argv, NULL);
>
> and in my embeded system runs like:
>
>
>
> Breakpoint 1, main (argc=2, argv=0xbffff294)
>     at
> /usr/src/build/snapgear/user/apache/server/main.c:441
> 441         int configtestonly = 0;
> (gdb) n
> 442         const char *confname = SERVER_CONFIG_FILE;
>
>
>
> it seems that, the hosting system doing something for init before the main
> function run, but embeded system do not?
>
> I thinks is here somthing wrong? or there should be some compiling
> parameters I missed?
>
> ======= 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.
> >
> >Graham
> >
> >
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>
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>
>
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> Àñ£¡
> 2008-03-03
>
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