[Crash-utility] dmesg content from crash without debug symbols

[Bouchard Louis]

Hi Dave,

Le 21/01/2013 14:37, Dave Anderson a écrit :
> 
> 
> ----- Original Message -----
>> Hello,
>>
>> Is it possible to extract the content of the kernel buffer (result of
>> the 'log' command) from a kernel dump without access to the kernel debug
>> symbols ?
>>
>> The intent is to be able to retrieve a minimal set of information from
>> the dump on a system that doesn't have to possibility to install the
>> namelist with debug symbols.
>>
>> TIA,
>>
>> Kind regards,
>>
>> ...Louis
>> --
>> Louis Bouchard
>> Backline Support Analyst
>> Canonical Ltd
>> Ubuntu support: http://landscape.canonical.com
> 
> Do you guys (Ubuntu) have makedumpfile as part of your kdump facility?
> It does just that, using the debug/offset information contained in
> the vmcoreinfo data:
> 
>  $ man makedumpfile
>  ...
>        --dump-dmesg
>               This option  overrides  the  normal  behavior  of  makedumpfile.
>               Instead  of  compressing  and  filtering  a  VMCORE  to  make it
>               smaller, it simply extracts the dmesg  log  from  a  VMCORE  and
>               writes it to the specified LOGFILE. If a VMCORE does not contain
>               VMCOREINFO for dmesg, it is necessary to specfiy [-x VMLINUX] or
>               [-i VMCOREINFO].
> 
>               Example:
>               # makedumpfile --dump-dmesg /proc/vmcore dmesgfile
>               # makedumpfile --dump-dmesg -x vmlinux /proc/vmcore dmesgfile
>  ...
> 
> Dave
> 
> --
> Crash-utility mailing list
> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility
> 

Yep, makedumpfile is used by default. How about that for self-inflicted
'ridicule'! I've been co-maintaining makedumpfile for Debian for the
last three releases, I should have known better :-)

Thanks for pointing me to that !

Kind regards,

...Louis

Now I know that
-- 
Louis Bouchard
Backline Support Analyst
Canonical Ltd
Ubuntu support: http://landscape.canonical.com