[Lguest] [PATCH] Fix lguest page-pinning logic ("lguest: bad stack page 0xc057a000")

[Rusty Russell]

On Thu, 2007-08-30 at 18:38 +0200, Frederik Deweerdt wrote: 
> On Tue, Aug 28, 2007 at 02:09:59AM +1000, Rusty Russell wrote:
> > If the stack pointer is 0xc057a000, then the first stack page is at
> > 0xc0579000 (the stack pointer is decremented before use).  Not
> > calculating this correctly caused guests with CONFIG_DEBUG_PAGEALLOC=y
> > to be killed with a "bad stack page" message: the initial kernel stack
> > was just preceeding the .smp_locks section which
> > CONFIG_DEBUG_PAGEALLOC marks read-only when freeing.
> > 
> Hello Rusty,
> 
> I just could try the patch, sorry for the delay. Albeit it allows to
> progress a little further in the boot process, lguest seems to like that
> "section that was just freed" :)

Yes, I got this too, then had to jump on a plane (and away from my test
box).

Turns out this actually isn't my bug (yay!).

See next patch...
Rusty.