Re: Determine version of kernel that produced vmcore

From: Neil Horman
Date: Tue Jul 10 2007 - 15:01:38 EST


On Tue, Jul 10, 2007 at 08:35:41PM +0300, Dan Aloni wrote:
> On Tue, Jul 10, 2007 at 01:17:40PM -0400, Neil Horman wrote:
> > On Tue, Jul 10, 2007 at 08:30:37PM +0530, Vivek Goyal wrote:
> > > I am still thinking that why can't we change initrd building process
> > > (Be it mkinitrd or mkdumprd depending on distriution). Whole idea is
> > > that while building an initrd/initramfs for the first kernel, one will
> > > ask user for kdump kernel (if user wishes to load kdump kenrel through
> > > initrd) and then it will generate kdump kenrel's initrd and pack into
> > > first kernel's initrd.
> > >
> > > So steps would look something like this.
> > >
> > > - mkinitrd takes second kernel's vmlinux as argument
> > > - mkinitrd runs "makedumpfile -g" on debug version of first kernel's vmlinux.
> > > - mkinitrd generates the initramfs for kdump kernel and packs output
> > > of "makedumpfile -g" into that.
> > > - mkinitrd packs statically linked kexec, kdump kernel vmlinux/bzImage,
> > > and kdump kernel initramfs into first kernel's initramfs.
> > >
> > Agreed, this is exactly what happens right now.
>
> 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

>
> --
> 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@xxxxxxxxxx
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*http://pgp.mit.edu
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