Re: vmcoreinfo: add the symbol "phys_base"

From: Vivek Goyal
Date: Thu Apr 17 2008 - 13:35:03 EST


On Thu, Apr 17, 2008 at 10:16:16AM -0700, Chris Wright wrote:
> * Eric W. Biederman (ebiederm@xxxxxxxxxxxx) wrote:
> > Chris Wright <chrisw@xxxxxxxxxxxx> writes:
> >
> > > -stable review patch. If anyone has any objections, please let us know.
> > > ---------------------
> >
> > This patch seems quite reasonable. However as I read it, it is
> > a feature enhancement, that allows a user space tool to function
> > better. Do we backport trivial features into stable now?
>
> Function better, meaning work reliably? Sounds like a fix not a
> feature.
>

I think in theory, makedumpfile should be able to guess phys_base by
looking at the vmcore ELF headers (Look for program headers which are
mapping kernel text and data and look at respective virtual address and
physical addresses.).

I think this patch just makes it explicit instead putting extra logic
for guessing the things.

To make sure makedumpfile is not broken with older kernels (in specific
configurations where phys_base is not zero), I think one can also modify
makedumpfile but I don't see any harm in putting this small change
in stable kernel.

Keni'chi, can you please throw some light here if makedumpfile is broken with
stable kernel or not (with phys_base not being zero).

Thanks
Vivek
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