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