[PATCH 1/2] mm/hmm: hmm_range_fault() NULL pointer bug

[Christoph Hellwig]

On Fri, Aug 23, 2019 at 03:17:52PM -0700, Ralph Campbell wrote:
> Although hmm_range_fault() calls find_vma() to make sure that a vma exists
> before calling walk_page_range(), hmm_vma_walk_hole() can still be called
> with walk->vma == NULL if the start and end address are not contained
> within the vma range.

Should we convert to walk_vma_range instead?  Or keep walk_page_range
but drop searching the vma ourselves?

Except for that the patch looks good to me:

Reviewed-by: Christoph Hellwig <hch at lst.de>