kernel fault in get_dump_page on at91

Hi,

It seems generating a coredump on an at91rm9200 with kernels 3.4 and 3.5
causes an oops.

The function get_dump_page calls vivt_flush_cache_page which tests if
the current cpu belongs to mm_cpumask(vma->vm_mm), but vma->vm_mm is
NULL for the vector page.

Setting gate_vma.vm_mm to &init_mm seems to avoid the issue, but I am
not sure this is the right thing to do.

Regards.

-- 
                                                                Gilles.