Fwd: [Crash-utility] crash without namelist?

[Dave Anderson]

Thanks Cai -- the capability will be in RHEL5.4 and it
looks to have been put in place in the upstream kernel
and sourceforge makedumpfile already.

The bugzillas referenced below are restricted access so I
removed the numbers, but the option allows you to extract
the log buffer from a kdump vmcore into an output file 
like this:

  # makedumpfile --dump-dmesg /proc/vmcore outputfile

Dave


----- Forwarded Message -----
From: "CAI Qian" <caiqian at redhat.com>
To: anderson at redhat.com
Cc: caiqian at redhat.com
Sent: Monday, May 11, 2009 7:56:36 PM GMT -05:00 US/Canada Eastern
Subject: Re: [Crash-utility] crash without namelist?

Hi Dave,

From: Dave Anderson <anderson at redhat.com>
Subject: Re: [Crash-utility] crash without namelist?
Date: Mon, 11 May 2009 16:55:00 -0400 (EDT)

> 
> ----- "urgrue" <urgrue at bulbous.org> wrote:
> 
>> ----- "Jun Koi" <junkoi2004 gmail com> wrote:
>> >> But I think sometimes we only have the System.map file in hand,
>> >> without the namelist. Can we do anything with that? Because in many
>> >> cases only some restricted operations are enough to debug the crashed
>> >> dump.
>> >
>> >The basic design of the crash utility is that it is essentially
>> >a huge wrapper around the embedded gdb module, taking advantage 
>> >of gdb's allowance of an alternative user interface.  So during
>> 
>> But is it really so that one can not get _any_ useful info from the dump
>> without the namelist?
>> Most of the time just the trace is all I need (i.e. that which is
>> displayed on the console in a panic). That info is not accessible
>> conveniently because a) the console can only show the last bits of it
>> and b) I'd rather autoreboot on a panic.
>> I know I can use netconsole, but it would just be more convenient if I
>> could read this from the core file easily.
> 
> I understand, but that's not how the crash utility is designed.
> You basically want to roll your own utility that doesn't have all
> the gdb dependencies that crash has.
> 
> If I'm not mistaken, wasn't there a proposed makedumpfile feature that
> would just pull the log buffer from a vmcore?  Or is that something
> from the diskdumputils package?  I know I've heard talk of it, but
> I can't recall where.
> 

Yes, it is in RHEL5.4.

This is the kexec-tools part of changes,
https://bugzilla.redhat.com/show_bug.cgi?id=xxxxxx

This is the kernel part of changes,
https://bugzilla.redhat.com/show_bug.cgi?id=xxxxxx

Thanks,
CAI Qian