[Crash-utility] crash can't read vmlinux on live system?

[Dave Anderson]

Kris Corwin wrote:

> I wasn't aware of the new driver, crash.  I have now
> built CONFIG_CRASH into my kernel.  crash still has
> trouble reading though.
>
> kris
>
> [root at f14 linux-2.6.9-22.0.2.EL]# crash -d7 ./vmlinux
>
> crash 4.0-2
> Copyright (C) 2002, 2003, 2004, 2005  Red Hat, Inc.
> Copyright (C) 2004, 2005  IBM Corporation
> Copyright (C) 1999-2005  Hewlett-Packard Co
> Copyright (C) 1999, 2002  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.
>
> get_live_memory_source: /dev/mem

On live systems, /dev/crash is used by default, but you're still getting /dev/mem.
One reason that it would fail to use /dev/crash is if the following command
doesn't show it:

 # /sbin/modprobe -l --type drivers/char

If it doesn't find "crash.o" or "crash.ko" in the list, it will give up on the
/dev/crash driver and default back to /dev/mem.

Dave