> -----Original Message----- > From: Wang, Haiyue > Sent: Sunday, August 14, 2022 14:20 > To: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: linux-mm@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; david@xxxxxxxxxx; linmiaohe@xxxxxxxxxx; Huang, > Ying <ying.huang@xxxxxxxxx>; songmuchun@xxxxxxxxxxxxx; naoya.horiguchi@xxxxxxxxx > Subject: RE: [PATCH v1] mm: migration: fix the FOLL_GET failure on following huge page > > > -----Original Message----- > > From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Sent: Sunday, August 14, 2022 07:29 > > To: Wang, Haiyue <haiyue.wang@xxxxxxxxx> > > Cc: linux-mm@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; david@xxxxxxxxxx; linmiaohe@xxxxxxxxxx; Huang, > > Ying <ying.huang@xxxxxxxxx>; songmuchun@xxxxxxxxxxxxx; naoya.horiguchi@xxxxxxxxx > > Subject: Re: [PATCH v1] mm: migration: fix the FOLL_GET failure on following huge page > > > > On Fri, 12 Aug 2022 16:49:21 +0800 Haiyue Wang <haiyue.wang@xxxxxxxxx> wrote: > > > > > Not all huge page APIs support FOLL_GET option, so the __NR_move_pages > > > will fail to get the page node information for huge page. > > > > Is a -stable backport warranted? > > Yes. > > Since the mainline has introduced the new patch: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3218f8712d6bb > Looks like 'is_zone_device_page' will cause 'FOLL_GET' page reference count issue, which should call 'put_page' before call branch jump. try_grab_page --> if (flags & FOLL_GET) folio_ref_inc(folio); Or I misunderstood the 'is_zone_device_page' ? ;-) > The backported needs to rebase like for 5.19: > > - if (page && !is_zone_device_page(page)) { > + if (page) { > > > > > >
