Make sure we populate the initroot filesystem late enough

[Benjamin Herrenschmidt]

On Sun, 2007-02-25 at 23:01 -0500, David Woodhouse wrote:

> Yeah, I did that before giving up on it for the day and going in search
> of dinner. It changes the failure mode to a BUG() in
> cache_free_debugcheck(), at line 2876 of mm/slab.c
> 
> It smells like the pages weren't actually reserved in the first place
> and we were blithely allocating them. The only problem with that theory
> is that the initrd doesn't seem to be getting corrupted -- and if we
> were handing out its pages like that then surely _something_ would have
> scribbled on it before we tried to read it.
> 
> When I head back in tomorrow morning I'll instrument free_initrd_mem()
> to check that the PageReserved bit was actually set on each page, before
> clearing it. And I'll make the page allocation routines check whether
> they're giving out pages between initrd_start and initrd_end, etc.

And check that we didn't end up stupidly having the initrd share a page
with something else ... (like not aligned end or such thingy).

Ben.