kdump from x86_64 using i386 capture kernel

Neil Horman nhorman at redhat.com
Fri Jan 4 10:49:31 EST 2008

On Fri, Jan 04, 2008 at 04:00:26PM +0100, Stanislaw Gruszka wrote:
> On Friday 04 January 2008 14:55, Neil Horman wrote:
> > > It is possible to achieve valid vmcore when first is x86_64 and capture 
> > > is i386 ?
> > Possible I think, but not reliable.  If oldmem has regions to capture above the
> > 4GB range, a 386 kernel won't be able to access those addresses, and as such,
> > you won't get a complete vmcore.
> Uffff, I missed this fact. 
> > I'm also confused about what exactly you are trying to accomplish.  Why are you
> > trying to use an x86 kernel to capture a x86_64 vmcore?  The available
> System load from flash and there is limited space. I tried to do one capture
> kernel, but see this was bad idea. I will scarify another 2MB and make separate
> image for x86_64. 

I'm still not quite understanding, the kernel image that you used to initally
boot the box should be suitable for loading as the kdump image.  Even if you're
using i386 instead of x86_64 as your kdump kernel, you still need to maintain
two images.

> > kexec-tools package in Fedora and RHEL provides a arch independent utility to
> > build a minimal initrd to capute vmcores via a number of targets, including via
> > nfs and ssh already (mkdumprd), have you looked at the Fedora package?  It may
> > well provide most/all of what you are trying to do.
> I will see, thanks.
Let me know if you have questions.

> Stanislaw Gruszka

 *Neil Horman
 *Software Engineer
 *Red Hat, Inc.
 *nhorman at redhat.com
 *gpg keyid: 1024D / 0x92A74FA1

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