Subject: Re: sparse, kernel-only crashdumps
To: None <>
From: David Young <>
List: tech-kern
Date: 10/07/2004 16:17:55
On Thu, Oct 07, 2004 at 01:39:11AM -0500, David Young wrote:
> It looks to me like it isn't too hard to make a sparse crashdump on x86
> that contains only the pages that are mapped into kernel virtual memory,
> the page directory and page table pages (PDP and PTPs).  Does a crashdump
> require any other pages?  I have a need for compact crashdumps, so I am
> going to work on this over the weekend.

Ok, just to clarify: I was not asking for new requirements.  I will see
what I can do to split i386 into generic MI/MD portions, but I have no
intention of writing generic crash dump support.  Cross-debugging is
totally out of the scope of this weekend project.  I have no interest
whatsoever in extending or fixing kcore/libkvm.  FWIW, I think the kcore
format is adequate to support i386 kernel-only dumps already.

I may have underestimated the amount of work this will take.  Just for
instance, I don't know how/where to find the kernel's .data or .bss
sections---I'd assumed they were in kernel virtual memory.  If you
have any pointers, it might save me a couple hours hunting through the
kernel sources.

I intend to commit whatever I come up with, when it works, as an option
enabled by 'options X86_KERNEL_ONLY_DUMP'.


David Young             OJC Technologies      Urbana, IL * (217) 278-3933