Re: [Xen-devel] Debian linux-image-2.6.32-4-xen-amd64 2.6.32-11 doesn't boot with > 4 GiB; resets immediatelly, no log messages

[Thomas Schwinge <thomas@xxxxxxxxxxxxx>]

Hello!

On Sat, Apr 10, 2010 at 03:52:45PM -0700, Jeremy Fitzhardinge wrote:
> On 04/10/2010 03:13 PM, Thomas Schwinge wrote:
> >> Normally that would be OK, because it uses:
> >>
> >>    __get_user(pfn, &machine_to_phys_mapping[mfn]);
> >>
> >> to dereference the array.  But at this early stage, none of the kernel's
> >> exception handlers have been set up, so this will just fault into Xen.
> >>
> >> It would be interesting to confirm this by building your kernel with
> >> CONFIG_DEBUG_INFO=y in the .config, and verify that the faulting
> >> instruction is actually this line.
> >>     
> > Bingo!
> 
> Excellent.  Now I just need to work out how to do a proper manual limit
> check on the mfn.  (I've always been a bit suspicious of this code,
> because there's no guarantee that a random invalid mfn *won't* happen to
> return the pfn we're looking for...)

Any news already about this one?


Regards,
 Thomas

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