On Fri, Aug 2, 2024 at 10:39 AM Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx> wrote:
> Calculating the size of the mapped area as the lesser value
> between the requested size and the actual size does not consider
> the partial mapping offset. This can cause page fault access.
>
> Fix the calculation of the starting and ending addresses, the
> total size is now deduced from the difference between the end and
> start addresses.
>
> Additionally, the calculations have been rewritten in a clearer
> and more understandable form.
>
> Fixes: c58305af1835 ("drm/i915: Use remap_io_mapping() to prefault all PTE in a single pass")
> Reported-by: Jann Horn <jannh@xxxxxxxxxx>
> Co-developed-by: Chris Wilson <chris.p.wilson@xxxxxxxxxxxxxxx>
> Signed-off-by: Chris Wilson <chris.p.wilson@xxxxxxxxxxxxxxx>
> Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.9+
Reviewed-by: Jann Horn <jannh@xxxxxxxxxx>
