Re: [mm-unstable PATCH v4 2/9] mm/hugetlb: separate path for hwpoison entry in copy_hugetlb_page_range()

["HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>]

On Sun, Jul 03, 2022 at 06:42:59PM -0700, Andrew Morton wrote:
> On Mon,  4 Jul 2022 10:33:05 +0900 Naoya Horiguchi <naoya.horiguchi@linux.dev> wrote:
> 
> > Originally copy_hugetlb_page_range() handles migration entries and hwpoisoned
> > entries in similar manner.  But recently the related code path has more code
> > for migration entries, and when is_writable_migration_entry() was converted
> > to !is_readable_migration_entry(), hwpoison entries on source processes got
> > to be unexpectedly updated (which is legitimate for migration entries, but
> > not for hwpoison entries).  This results in unexpected serious issues like
> > kernel panic when forking processes with hwpoison entries in pmd.
> > 
> > Separate the if branch into one for hwpoison entries and one for migration
> > entries.
> > 
> > ...
> >
> > Cc: <stable@vger.kernel.org> # 5.18
> 
> It's unusual to have a cc:stable patch in the middle of a series like
> this.  One would expect the fix to be a standalone thing against
> current -linus.

Ah, OK, I should've submit this seperately.

> 
> As presented, this patch won't get into mainline until after 5.20-rc1. 
> If that's OK then OK.  Otherwise I can shuffle things around and stage
> this patch in mm-hotfixes?

Yes, I'd like to ask you to do it. Thank you for the arrangement.

- Naoya Horiguchi