Re: [Patch] min_low_pfn and max_low_pfn calcultion fix

From: Horms <horms_at_verge.net.au>
Date: 2007-03-15 12:55:52
On Wed, Mar 14, 2007 at 11:48:15AM -0700, Jay Lan wrote:
> Jay Lan wrote:
> > Jay Lan wrote:
> >> Magnus Damm wrote:
> >> [snip]
> >>>> I tested on 2.6.21-rc3 with DEBUG_VM turned on. The vanilla 2.6.21-rc3
> >>>> without Nan-hai's patch, panicked on bugcheck on free_initmem->free_page
> >>>> as predicted. We still need this patch.
> >>> Ok, thanks for testing. =)
> >>>
> >>>> However, the zero-size vmcore problem is back on SN. But that is a
> >>>> dfiffernet problem.
> >>> Argh, more problems...
> >> I found the problem. It was the "elfcorehdr" introduced in 2.6.21-rc1.
> >> Without specifying it, the elfcorehdr_addr is initialized to
> >> ELFCORE_ADDR_MAX. Later, a check in reserve_elfcorehdr will fail:
> >>         if (elfcorehdr_addr >= ELFCORE_ADDR_MAX)
> >>                 return -EINVAL;
> >>
> >> Is it supposed to be a physical address to store elf core header?
> >> If so, it is not possible for SN to provide a physical address at
> >> boot time, just like in the case of crashkernel=X@Y where Y is not used.
> > 
> > Sorry, the elfcorehdr parameter is provided to the kdump kernel by
> > kexec. The problem is in the reserve_elfcorehdr logic introduced in
> > 2.6.21-rc1.
> > 
> > When booting up the kdump kernel, i observed a failure in
> > reserve_elfcorehdr. The below are my debugging messages:
> > 
> > elfcorehdr_addr=3027fe4000, ELFCORE_ADDR_MAX=ffffffffffffffff
> > Cannot locate EFI vmcore descriptor
> > reserve_elfcorehdr: vmcore descriptor size = 0
> > reserve_memory: FAIL to reserve reserve_elfcorehdr
> 
> Hi Tony,
> 
> The kernel code 2.6.21-rc3+ is fine wrt zero-size-vmcore issue.
> 
> I have been testing on a rhel5 environment. The /sbin/kexec worked
> for me up to 2.6.20.
> 
> I then built a new kexec from tot kexec-tools-testing git tree and
> i no longer see the zero-size-vmcore problem.

I take it that elfcorehdr is also correct in this environment?

The latest (ia64) kernels need a fairly recent kexec-tools-testing
because of the change "kexec: Use EFI_LOADER_DATA for ELF core header".
A recent kexec-tools-testing is probably needed for other reasons,
though I can't think of them off-hand.

-- 
Horms
  H: http://www.vergenet.net/~horms/
  W: http://www.valinux.co.jp/en/

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Received on Thu Mar 15 13:00:54 2007

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