----- Original Message -----
 Hi,
 I am using KDUMP tools( version: 2.0.4 ) to capture kernel panic information.
 I configured the kernel compile para according to the kdump-tutorial, and
 get dump file in /var/crash/ through echo c > /proc/sysrq-trigger . but when
 I analyze the dump file using command: crash -d8 vmlinux dumpfile
 error happens as following:
 crash: seek error: kernel virtual address: c1625ccc type: "cpu_possible_mask"
 The more log can be seen in the attachment: crash.log
 
 Otherwise, I found the size of dump file(dump-incomplete) is about 25M, but
 my memory is 4G. why the dump file is so small?
 My linux version is linux Mint15, basing on Ubuntu, the kernel version is
 3.8.13 .
 
 v10@COS-Desktop ~ $
 v10@COS-Desktop ~ $ cat /proc/cmdline
 BOOT_IMAGE=/boot/vmlinuz-3.8.13.13-cos-i686
 root=UUID=c0bd0f62-0dfa-4425-8afa-b5ff8a00df5c ro
 crashkernel=384M-2G:64M,2G-:128M quiet splash
 v10@COS-Desktop ~ $
 v10@COS-Desktop ~ $ cat /var/crash/kexec_cmd
 /sbin/kexec -p --command-line="BOOT_IMAGE=/boot/vmlinuz-3.8.13.13-cos-i686
 root=UUID=c0bd0f62-0dfa-4425-8afa-b5ff8a00df5c ro quiet splash irqpoll
 maxcpus=1 nousb " --initrd=/boot/initrd.img-3.8.13.13-cos-i686
 /boot/vmlinuz-3.8.13.13-cos-i686
 v10@COS-Desktop ~ $
 v10@COS-Desktop ~ $
 
 other log:
 v10@COS-Desktop ~ $ sudo crash --minimal kdump/0211/vmlinux
/var/crash/201402120848/dump-incomplete 
I am not familiar with Ubuntu's handling of the kexec-tools package,
but presumably when the kdump procedure starts, it opens the dumpfile
with the name "dump-incomplete".  And after the procedure completes
successfully, it would change the dumpfile name to "vmcore".  Since
the dumpfile remained named as "dump-incomplete", the kdump procedure
apparently failed.
 [sudo] password for v10:
 
 crash 6.1.6
 Copyright (C) 2002-2013 Red Hat, Inc.
 Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation
 Copyright (C) 1999-2006 Hewlett-Packard Co
 Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited
 Copyright (C) 2006, 2007 VA Linux Systems Japan K.K.
 Copyright (C) 2005, 2011 NEC Corporation
 Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc.
 Copyright (C) 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 under
 certain conditions. Enter "help copying" to see the conditions.
 This program has absolutely no warranty. Enter "help warranty" for details.
 
 GNU gdb (GDB) 7.3.1
 Copyright (C) 2011 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 "i686-pc-linux-gnu"...
 
 NOTE: minimal mode commands: log, dis, rd, sym, eval, set, extend and exit
 
 crash>
 crash>
 crash> rd linux_banner 30
 rd: seek error: kernel virtual address: c1622080 type: "32-bit KVADDR"
 crash>
 crash>
 crash> 
A "seek error" simply means that the physical memory page was not found
in the (incomplete) dumpfile.
But this is not a crash utility issue, but rather a problem with your
system's handling of the the kdump procedure.  A dump of the secondary
kernel's output (if available) may shed some light on what the problem
was.
Dave Anderson