Re: [PATCH] mm: migrate: add missing flush_dcache_page for non-mapped page migrate

[Lars Persson]

On 2/26/19 11:07 AM, Vlastimil Babka wrote:
> On 2/26/19 9:40 AM, Lars Persson wrote:
> > > What about CC stable and a Fixes tag, would it be applicable here?
> >
> > Yes this is candidate for stable so let's add:
> > Cc: <stable@xxxxxxxxxxxxxxx>
> >
> > I do not find a good candidate for a Fixes tag.
>
> How bout a version range where the bug needs to be fixed then?

The distinction between mapped and non-mapped old page was introduced in 2ebba6b7e1d9 ("mm: unmapped page migration avoid unmap+remap overhead") so at least it applies to stable 4.4+.

Before that patch there was always a call to remove_migration_ptes() but I cannot conclude if those earlier versions actually will reach the flush_dcache_page call if the old page was unmapped.