Re: [syzbot] WARNING in follow_hugetlb_page

[John Hubbard]

On 5/13/22 16:54, Minchan Kim wrote:
> > > I isolated this to Minchan Kim's "mm: fix is_pinnable_page against on cma
> > > page".  Yes, the fat finger fix is in next-20220513.
> > >
> > > I don't have time to analyze right now, but can confirm that in the
> > > reproducer is_pinnable_page is returning false after this change when it
> > > previously returned true.
> >
> > OK, thanks, I dropped mm-fix-is_pinnable_page-against-on-cma-page.patch
>
> Seems like bug of the patch v5 due to change of this
>
>      if (mt & (MIGRATE_CMA | MIGRATE_ISOLATE))
>
> The migration type is not bit type so it shold be
>
> if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)

Sorry for leading you astray by recommending the bitwise OR, Minchan.
I overlooked that point even though it was right in front of me.


thanks,
--
John Hubbard
NVIDIA