Gdb error while debugging core file Post: 302891662

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Operating Systems Linux Red Hat Gdb error while debugging core file Post 302891662 by sanzee007 on Friday 7th of March 2014 05:54:40 AM

03-07-2014

Registered User

Gdb error while debugging core file

Hi,
I am trying to analyze one core file on my RHEL 6.5, but I am getting below error related to the core file. So I am not getting any stack trace about the crash.

Code:

#  gdb MyDebugBin /var/core/MyDebugBin.27005
GNU gdb (GDB) Red Hat Enterprise Linux (7.2-60.el6_4.1)
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from MyDebugBin...done.
BFD: Warning: MyDebugBin.27005 is truncated: expected core file size >= 47775744, found: 2387968.
[New Thread 27005]
Cannot access memory at address 0x4baca8e8
Cannot access memory at address 0x4baca8e8
Cannot access memory at address 0x4baca8e8
Reading symbols from /lib/ld-linux.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/ld-linux.so.2
Failed to read a valid object file image from memory.
Core was generated by `/path_to_my_debug_bin/MyDebugBin :12 -auth /var/run/gdm/auth-for-gdm-kUgSIC/database'.
Program terminated with signal 11, Segmentation fault.
#0  0x4bb48506 in ?? ()
Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.132.el6.i686
(gdb) bt
#0  0x4bb48506 in ?? ()
Cannot access memory at address 0xffe51198
(gdb) quit

Why gdb is complaining about the core size? There is enough space left for core files with ulimit unlimited set for core file.

How to fix this kind of error or problem related to gdb? Is it a known bug in gdb on higher version of linux kernel?

thanks,

sanzee007

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LEARN ABOUT FREEBSD

kgdb

KGDB(1) 						    BSD General Commands Manual 						   KGDB(1)

NAME

     kgdb -- kernel debugger

SYNOPSIS

     kgdb [-a | -f | -fullname] [-b rate] [-q | -quiet] [-v] [-w] [-d crashdir] [-c core | -n dumpnr | -r device] [kernel [core]]

DESCRIPTION

     The kgdb utility is a debugger based on gdb(1) that allows debugging of kernel core files.

     The options are as follows:

     -a 	  Increase the annotation level.  An annotation level of 1 features the historical -fullname option of gdb(1).	This is useful
		  when running kgdb in Emacs.  The -f or -fullname options are supported for backward compatibility as well.

     -b rate	  Set the baudrate to rate.

     -q 	  Suppress printing of the banner when the debugger starts.  The -quiet form is supported for compatibility as well.

     -v 	  Increase verbosity.

     -w 	  Opens kmem-based targets in read-write mode.	(This is identical to what --wcore used to do in previous gdb versions for
		  FreeBSD.)

     -d crashdir  Use crashdir instead of the default, /var/crash to locate kernel core dump files in.	The name vmcore. plus the dump number will
		  be appended to determine the actual dump file name.

     -c core	  Explicitly use core as the core dump file.

     -n dumpnr	  Use the kernel core dump file numbered dumpnr for debugging.

     -r device	  Use device to connect kgdb to for a remote debugging session.

     The -c, -n, and -r options are mutually exclusive.

     Optionally, the name of the kernel symbol file and the name of the core dump file can be supplied on the command-line as positional argu-
     ments.  If no kernel symbol file name has been given, the symbol file of the currently running kernel will be used.  If no core dump file has
     been specified through either of the options or the last command-line argument, /dev/mem will be opened to allow debugging the currently run-
     ning kernel.

FILES

     /dev/mem	 Default memory image to open if no core dump file has been specified.

     /var/crash  Default directory to locate kernel core dump files.

SEE ALSO

     gdb(1)

HISTORY

     The kgdb utility first appeared in its current form in FreeBSD 5.3.

BSD
								 October 11, 2006							       BSD