Re: Determine version of kernel that produced vmcore

Neil Horman
2007-07-11T11:58:05Z

On Tue, Jul 10, 2007 at 11:36:45PM +0300, Dan Aloni wrote:
> On Tue, Jul 10, 2007 at 03:00:09PM -0400, Neil Horman wrote:
> > On Tue, Jul 10, 2007 at 08:35:41PM +0300, Dan Aloni wrote:
> >[...]
> > >
> > > Isn't there some sort of a circular dependency going on here? As I
> > > understand it the vmlinux binary already contains the initramfs as
> > > built-in data (at least that's what I use here for initramfs). It
> > You're misunderstood. The vmlinux binary and the initramfs are stored in the
> > same protected memory area when you execute a kexec -l, but they are separate
> > and distinct files.
> >
> > > makes more sense if you guys are creating an _initrd_ image (that's
> > > what mkinitrd originally did AFAIK) and supply it to the boot-loader.
> > initrd is old, initramfs is the new way to go, but they effecitvley do the same
> > thing, and while the initramfs _can_ be built into the kernel, it can also be
> > separately managed (which is what most distros tend to do, AFAICS).
> > Neil
>
> Yes, I was under the impression that the external initramfs was the
> 'special case' and I seem to forget about it, I guess that's what most
> kernel distribution still do (I haven't been using a distribution-supplied
> kernel for quite a while...).
>
> Anyway, the patches I contributed in one the previous mail (didn't reach
> the kexec list due to moderation but available on LKML) can help with
> what Bernhard is aiming for. I took quite a dive into makedumpfile's code
> to figure out what's the best way to integrate it. What I was thinking
> was something in the lines of:
>
> * early on, detect if /proc/vmcore has a LINUX elf note
> * if it has, then don't require '-x' or '-i' on the command line,
> extract it to a temporary file and treat it as a CONFIGFILE for
> the rest of the code flow.
> * otherwise, continue with the regular flow.
>
This would make sense to me.

> For just extracting OSRELEASE, it is possible to write a simple program or
> script that searches for it at the first few kilobytes of the file.
>
Also seems reasonable.

Regards
Neil

> --
> Dan Aloni
> XIV LTD, http://www.xivstorage.com
> da-x (at) monatomic.org, dan (at) xiv.co.il

--
/***************************************************
*Neil Horman
*Software Engineer
*Red Hat, Inc.
*nhorman@redhat.com
*gpg keyid: 1024D / 0x92A74FA1
*http://pgp.mit.edu
***************************************************/