Re: problems debugging panic with gdb, kdump, and vmcore

[Robert Hancock <hancockrwd@gmail.com>]

On 07/20/2009 10:46 PM, Steven Noonan wrote:
> Hi folks,
>
> I've got a kernel panic that is easily reproducible (I am 99% sure
> that 2.6.30.2 itself isn't to blame, it's the out-of-tree drm module I
> built from here: http://cgit.freedesktop.org/mesa/drm/). I could just
> follow the stack trace, but I'd like to learn how to use kexec/kdump
> to debug this. So far, I've got kexec successfully loading a kernel on
> a panic, and I'm able to copy the vmcore out of /proc to someplace
> permanent, but trying to use gdb on it gives very strange results. I
> don't know what I'm doing wrong. I've rebuilt the kernel multiple
> times and ensured that ccache is cleared each time just in case that
> might interfere. Here's what I'm getting with gdb:
>
>
> Alcarin linux # pwd
> /usr/src/linux
> Alcarin linux # gdb vmlinux /var/tmp/vmcore
> GNU gdb 6.8
> Copyright (C) 2008 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"...
>
> warning: exec file is newer than core file.

Why is the vmlinux file newer than the vmcore file?