Seg Fault Issues- mod_perl and XML::Parser

[Tom Harper <to...@auctionet.com>]

Hi--

Having a problem with modperl/xml-parser.

I have been encountering mysterious segfault errors in apache
child processes when it is under load, and I am trying to narrow 
down what is happening.

replacing the die statements from Parser.pm helped get rid of
alot of the segs, but this issue still crops up periodically.

i also made sure that apache compiled with Expat=no.

I have included the most common stacktrace from gbd below (i 
have several others).

All seem to be related to expat, but i can't tell exactly 
what is breaking from the trace.  Any help deciphering the
trace would be greatly appreciated!

Also, I would like to use this trick so that I can get more 
info on mod perl-- 

(gdb) source modperl_x.xx/.gdbinit
(gdb) curinfo

Do I need to re-compile perl with DEBUG for this to work?

Also, i can't seem to find .gdbinit-- don't know if this will
help this problem in any case, but would like to at least have
this in the tool chest.

I am working with:
mod perl 1.23
linux 6.2
apache 1.39
XML::Parser 2.29

Program received signal SIGSEGV, Segmentation fault.
0x8118fc5 in Perl_sv_setsv ()
(gdb) bt
#0  0x8118fc5 in Perl_sv_setsv ()
#1  0x8110bb3 in Perl_pp_sassign ()
#2  0x811083d in Perl_runops_standard ()
#3  0x8131dce in Perl_pp_exit ()
#4  0x8131e45 in Perl_pp_exit ()
#5  0x8133dfc in Perl_pp_entertry ()
#6  0x811083d in Perl_runops_standard ()
#7  0x80d88d5 in perl_call_sv ()
#8  0x80d8494 in perl_call_sv ()
#9  0x402e8e76 in endElement () from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#10 0x80c03e6 in XML_ErrorString ()
#11 0x80bf559 in XML_ErrorString ()
#12 0x80c1ddb in XML_ErrorString ()
#13 0x80c1b12 in XML_ErrorString ()
#14 0x80bf0f2 in XML_ParseBuffer ()
#15 0x402e877f in parse_stream () from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#16 0x402ebd16 in XS_XML__Parser__Expat_ParseStream ()
   from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#17 0x81157a5 in Perl_pp_entersub ()
#18 0x811083d in Perl_runops_standard ()
#19 0x8131dce in Perl_pp_exit ()
#20 0x8131e45 in Perl_pp_exit ()
#21 0x8133dfc in Perl_pp_entertry ()
#22 0x811083d in Perl_runops_standard ()
#23 0x80d88d5 in perl_call_sv ()
#24 0x80d8494 in perl_call_sv ()
#25 0x402e8e76 in endElement () from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#26 0x80c03e6 in XML_ErrorString ()
#27 0x80bf559 in XML_ErrorString ()
#28 0x80c1ddb in XML_ErrorString ()
#29 0x80c1b12 in XML_ErrorString ()
#30 0x80bf0f2 in XML_ParseBuffer ()
#31 0x402e877f in parse_stream () from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#32 0x402ebd16 in XS_XML__Parser__Expat_ParseStream ()
   from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#33 0x81157a5 in Perl_pp_entersub ()
#34 0x811083d in Perl_runops_standard ()
#35 0x8131dce in Perl_pp_exit ()
#36 0x8131e45 in Perl_pp_exit ()
#37 0x8133dfc in Perl_pp_entertry ()
#38 0x811083d in Perl_runops_standard ()
#39 0x80d88d5 in perl_call_sv ()
#40 0x80d8494 in perl_call_sv ()
#41 0x402e8e76 in endElement () from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#42 0x80c01df in XML_ErrorString ()
#43 0x80bf559 in XML_ErrorString ()
#44 0x80c1ddb in XML_ErrorString ()
#45 0x80c1b12 in XML_ErrorString ()
#46 0x80bf0f2 in XML_ParseBuffer ()
#47 0x402e877f in parse_stream () from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#48 0x402ebd16 in XS_XML__Parser__Expat_ParseStream ()
   from
/usr/local/lib/perl5/site_perl/5.6.0/i686-linux/auto/XML/Parser/Expat/Expat.so
#49 0x81157a5 in Perl_pp_entersub ()
#50 0x811083d in Perl_runops_standard ()
#51 0x80d88d5 in perl_call_sv ()
#52 0x80d869e in perl_call_sv ()
#53 0x807ca7b in perl_call_handler ()
#54 0x807c426 in perl_run_stacked_handlers ()
#55 0x807b17d in perl_handler ()
#56 0x8096093 in ap_invoke_handler ()
#57 0x80a9469 in ap_some_auth_required ()
#58 0x80a94cc in ap_process_request ()
#59 0x80a0e8e in ap_child_terminate ()
#60 0x80a101c in ap_child_terminate ()
#61 0x80a1179 in ap_child_terminate ()
#62 0x80a17a6 in ap_child_terminate ()
#63 0x80a1f23 in main ()
#64 0x400a81eb in __libc_start_main (main=0x80a1bec <main>, argc=2,
argv=0xbffffcd4, init=0x80627f0 <_init>, 
    fini=0x814dc9c <_fini>, rtld_fini=0x4000a610 <_dl_fini>,
stack_end=0xbffffccc)
    at ../sysdeps/generic/libc-start.c:90

Re: Seg Fault Issues- mod_perl and XML::Parser

[Matt Sergeant <ma...@sergeant.org>]

On Wed, 1 Nov 2000, Tom Harper wrote:

> Hi--
> 
> Having a problem with modperl/xml-parser.

Aren't we all :-)

Try http://axkit.org/faq.xml

Also, there is a patch for this (finally!) in http://axkit.org/download/ -
the mod_dav-shared-expat patch. I've sent this to Greg Stein (but not
heard any response yet).

-- 
<Matt/>

    /||    ** Director and CTO **
   //||    **  AxKit.com Ltd   **  ** XML Application Serving **
  // ||    ** http://axkit.org **  ** XSLT, XPathScript, XSP  **
 // \\| // **     Personal Web Site: http://sergeant.org/     **
     \\//
     //\\
    //  \\

Re: Seg Fault Issues- mod_perl and XML::Parser

["G.W. Haywood" <ge...@www.jubileegroup.co.uk>]

Hi there,

On Wed, 1 Nov 2000, Tom Harper wrote:

> Having a problem with modperl/xml-parser.
> mod perl 1.23
> linux 6.2
> apache 1.39
> XML::Parser 2.29

and evidently Perl 5.6.0!

No idea what might be the trouble, but I'd say get the latest of
everything *except* Perl.  I'd use 5.005_03 and compile everything
with debugging symbols.  Apach 1.3.9 is a bit old now, isn't it, but
I'm still using it somewhere (I forget exactly where, so it must be
fairly stable:).  Though I've never used XML::Parser so all this is
completely out of my hat.

Is that Red Hat Linux 6.2?  I had some problems in the summer with
that choking on certain hardware ('Gateway' 750MHz PentiumII), when
6.1 was fine.  So I used 6.1.

73,
Ged.