Red Hat Enterprise Linux 5 Administration Unleashed

Saving Kernel Dumps for Analysis 441directory. If the location is set to a partition, the vmcore file can be found in the/var/crash// directory inside the directory in which the partition is mounted.If a network location (NFS or SSH) is configured, the vmcore file is transferred to the/var/crash/-/ directory inside the directory specified along with thenetwork server name. If a raw partition is used, the contents of the core dump are locatedon the raw partition. Remember that if an alternate directory is set with the path variable,the /var/crash/ directory in these locations should be replaced with this differentdirectory.21After a vmcore file is created, it can be interactively analyzed with the crash program.Make sure you have the crash RPM installed to use it. The vmlinux file for the kernel isalso required to use crash. It is provided by the kernel-debuginfo package. A kerneldebuginfopackage exists for each kernel version, so be sure to install the correct version.It is available via FTP from the ftp.redhat.com FTP server. After logging in as an anonymoususer, change into the pub/redhat/linux/enterprise//en/os//Debuginfo/ directory, replacing and with the appropriate values foryour system such as 5Server for the and x86_64 for the . You can alsoview the list of packages by visiting http://ftp.redhat.com/ in a web browser.To start analyzing the file, execute the command crash as the rootuser. Be sure to use the full path to the if it is not in the current directory.(replace with the kernel version that was running when the crashoccurred):crash /usr/lib/debug/lib/modules//vmlinux vmcoreStarting the utility displays the output from Listing 21.5.LISTING 21.5Starting the crash Utilitycrash 4.0-3.11Copyright 2002, 2003, 2004, 2005, 2006 Red Hat, Inc.Copyright 2004, 2005, 2006 IBM CorporationCopyright 1999-2006 Hewlett-Packard CoCopyright 2005 Fujitsu LimitedCopyright 2005 NEC CorporationCopyright 1999, 2002 Silicon Graphics, Inc.Copyright 1999, 2000, 2001, 2002 Mission Critical Linux, Inc.This program is free software, covered by the GNU General Public License,and you are welcome to change it and/or distribute copies of it undercertain conditions. Enter “help copying” to see the conditions.This program has absolutely no warranty. Enter “help warranty” for details.GNU gdb 6.1Copyright 2004 Free Software Foundation, Inc.GDB is free software, covered by the GNU General Public License, and you arewelcome to change it and/or distribute copies of it under certain conditions.