The patch titled Subject: mm: migrate: fix an incorrect call of prep_transhuge_page() has been added to the -mm tree. Its filename is mm-migrate-fix-an-incorrect-call-of-prep_transhuge_page.patch

This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-migrate-fix-an-incorrect-call-of... and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-migrate-fix-an-incorrect-call-of...

Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/SubmitChecklist when testing your code ***

The -mm tree is included into linux-next and is updated there every 3-4 working days

------------------------------------------------------ From: Zi Yan zi.yan@cs.rutgers.edu Subject: mm: migrate: fix an incorrect call of prep_transhuge_page()

In https://lkml.org/lkml/2017/11/20/411, Andrea reported that during memory hotplug/hot remove prep_transhuge_page() is called incorrectly on non-THP pages for migration, when THP is on but THP migration is not enabled. This leads to a bad state of target pages for migration.

This patch fixes it by only calling prep_transhuge_page() when we are certain that the target page is THP.

Link: http://lkml.kernel.org/r/20171121021855.50525-1-zi.yan@sent.com Fixes: 8135d8926c08 ("mm: memory_hotplug: memory hotremove supports thp migration") Signed-off-by: Zi Yan zi.yan@cs.rutgers.edu Reported-by: Andrea Reale ar@linux.vnet.ibm.com Cc: Naoya Horiguchi n-horiguchi@ah.jp.nec.com Cc: Michal Hocko mhocko@kernel.org Cc: "Jérôme Glisse" jglisse@redhat.com Cc: stable@vger.kernel.org [4.14] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

include/linux/migrate.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN include/linux/migrate.h~mm-migrate-fix-an-incorrect-call-of-prep_transhuge_page include/linux/migrate.h --- a/include/linux/migrate.h~mm-migrate-fix-an-incorrect-call-of-prep_transhuge_page +++ a/include/linux/migrate.h @@ -54,7 +54,7 @@ static inline struct page *new_page_node new_page = __alloc_pages_nodemask(gfp_mask, order, preferred_nid, nodemask);

- if (new_page && PageTransHuge(page)) + if (new_page && PageTransHuge(new_page)) prep_transhuge_page(new_page);

return new_page; _

Patches currently in -mm which might be from zi.yan@cs.rutgers.edu are

mm-migrate-fix-an-incorrect-call-of-prep_transhuge_page.patch