topic Re: how to debug the core dump file created by perl script in Operating System - HP-UX

how to debug the core dump file created by perl script

yangk — Thu, 27 Jan 2011 02:31:53 GMT

Hi All,

I have a perl script which create a core dump,

root# file core.22
core.22: ELF-32 core file - IA64 from 'test' - received SIGSEGV

So is there any method which i can see the stack where the core happens?

Thanks in advance!
Kevin

Re: how to debug the core dump file created by perl script

Manix — Thu, 27 Jan 2011 06:10:34 GMT

#try gdb core file
example ..gdb /opt/bin/script.pl /core

Thanks
Manix

Re: how to debug the core dump file created by perl script

yangk — Thu, 27 Jan 2011 08:04:16 GMT

Hi Manix,

I have tried that way, but the gdb will report "not in executable format: File format not recognized".

I want to see the stack where the coredump happened.

Kevin

Re: how to debug the core dump file created by perl script

Manix — Thu, 27 Jan 2011 08:29:57 GMT

Hello Kevin,

Please try with below options as per man page.
Should work ,do check the permissions.

gdb [-help] [-e executable-name] [-pid] [-c corefile-name]

Thanks
Manix

Re: how to debug the core dump file created by perl script

Matti_Kurkela — Thu, 27 Jan 2011 09:36:02 GMT

When you're examining a core dump produced by a script, the executable should be the script interpreter, i.e. the "perl" binary in your case.

MK

Re: how to debug the core dump file created by perl script

yangk — Thu, 27 Jan 2011 10:15:26 GMT

Hi MK,

Ok, i try your way to debug the core.
root # gdb /usr/bin/perl core

warning: core file may not match specified executable file.
Core was generated by `test'.
Program terminated with signal 11, Segmentation fault.
SEGV_MAPERR - Address not mapped to object

warning: Some of the libraries in the core file are different from the libraries on this computer. It might be possible to proceed with your debugging process successfully. However, if you run into problems you must use packcore command or use the versions of the libraries used by the core. The mismatches are:

/usr/lib/hpux32/libnsl.so.1 in the core file is different from
/usr/lib/hpux32/libnsl.so.1 used by gdb

/usr/lib/hpux32/libnss_nis.so.1 in the core file is different from
/usr/lib/hpux32/libnss_nis.so.1 used by gdb

warning: No unwind information found.
Skipping this library /usr/lib/hpux32/libcl.so.1.

#0 0x60000000c03a3260:0 in tree_delete+0x20 () from /usr/lib/hpux32/libc.so.1
(gdb) bt
#0 0x60000000c03a3260:0 in tree_delete+0x20 () from /usr/lib/hpux32/libc.so.1
#1 0x60000000c039fe50:0 in real_realloc+0x1410 ()
from /usr/lib/hpux32/libc.so.1
#2 0x60000000c039ea00:0 in _realloc+0xa0 () from /usr/lib/hpux32/libc.so.1
#3 0x60000000c03ac2f0:0 in realloc+0x230 () from /usr/lib/hpux32/libc.so.1
#4 0x60000000c8bf0c80:0 in Perl_safesysrealloc () at util.c:124
#5 0x60000000c8c55670:0 in Perl_sv_grow () at sv.c:1660
#6 0x60000000c4f7a4b0:0 in PerlIOScalar_write () at scalar.xs:132
#7 0x60000000c8d89e90:0 in Perl_PerlIO_write () at perlio.c:1593
#8 0x60000000c8d34e20:0 in Perl_do_print () at doio.c:1354
#9 0x60000000c8c36d00:0 in Perl_pp_print () at pp_hot.c:625
#10 0x60000000c8c2fc00:0 in Perl_runops_standard () at run.c:38
#11 0x60000000c8b32220:0 in S_run_body () at perl.c:2361
#12 0x60000000c8b319b0:0 in perl_run () at perl.c:2283
#13 0x4001ff0:0 in main () at perlmain.c:99

But it seems that we can not see where the perl script create coredump.

Thanks!
Kevin

Re: how to debug the core dump file created by perl script

James R. Ferguson — Thu, 27 Jan 2011 13:45:55 GMT

Hi Kevin:

I think you want to read the section entitled "Debugging" here:

http://perldoc.perl.org/perlhack.html

Regards!

...JRF...

Re: how to debug the core dump file created by perl script

Dennis Handly — Fri, 28 Jan 2011 12:07:18 GMT

#0 0x60000000c03a3260:0 in tree_delete+0x20 /usr/lib/hpux32/libc.so.1
#1 0x60000000c039fe50:0 in real_realloc+0x1410
#2 0x60000000c039ea00:0 in _realloc+0xa0
#3 0x60000000c03ac2f0:0 in realloc+0x230
#4 0x60000000c8bf0c80:0 in Perl_safesysrealloc util.c:124
#5 0x60000000c8c55670:0 in Perl_sv_grow sv.c:1660
#6 0x60000000c4f7a4b0:0 in PerlIOScalar_write scalar.xs:132

This indicates that perl has corrupted the heap.