[Crash-utility] Question about: crash: seek error: kernel virtual address: c1625ccc type: "cpu_possible_mask"

[Dave Anderson]

----- 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 at COS-Desktop ~ $
> v10 at 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 at COS-Desktop ~ $
> v10 at 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 at COS-Desktop ~ $
> v10 at COS-Desktop ~ $
> 
> other log:
> v10 at 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