Re: [PATCH 11/11] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk()

[Hugh Dickins]

On Thu, 10 Jun 2021, Kirill A. Shutemov wrote:
> On Wed, Jun 09, 2021 at 11:54:46PM -0700, Hugh Dickins wrote:
> > Aha!  Shouldn't that quick scan over pte_none()s make sure that it holds
> > ptlock in the PVMW_SYNC case?  That too might have been responsible for
> > BUGs or WARNs in split_huge_page_to_list() or its unmap_page(), though
> > I've never seen any.
> > 
> > Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()")
> > Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx>
> 
> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

Thanks Kirill.

And Wang Yugui has now reported the good news, that this afterthought
patch finally fixes the unmap_page() BUGs they were hitting on 5.10.

Andrew, please add a link to
https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@xxxxxxxxxxxx/
and
Tested-by: Wang Yugui <wangyugui@xxxxxxxxxxxx>

Thanks,
Hugh