RPI-B VM panic

[Hans Petter Selasky]

>
> This output shows that according to the object's list of pages there is
> already a page allocated at pindex 4 (or "off=0x4" above).  If this list
> is correct, and not itself corrupted, then we shouldn't be making a call
> to vm_page_alloc() to allocate another page at the same pindex.
>
> Whether it is this list of pages that is corrupted or not, this means
> that the object's list of pages (shown above) and its radix tree of
> pages are out of sync.
>
> I'm curious to know what mpred is when the assertion fails.  That will
> tell us something about the state of the radix tree.
>
> I've also modified ddb's "show object" to provide an additional bit of
> information.  However, it would be really nice if "show object"
> displayed the state of the radix tree.
>
>

This patch makes no change.

--HPS