The patch titled Subject: mm/hugetlb: correct demote page offset logic has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-hugetlb-correct-demote-page-offset-logic.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Doug Berger opendmb@gmail.com Subject: mm/hugetlb: correct demote page offset logic Date: Wed, 14 Sep 2022 12:09:17 -0700

With gigantic pages it may not be true that struct page structures are contiguous across the entire gigantic page. The nth_page macro is used here in place of direct pointer arithmetic to correct for this.

Link: https://lkml.kernel.org/r/20220914190917.3517663-1-opendmb@gmail.com Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") Signed-off-by: Doug Berger opendmb@gmail.com Cc: Mike Kravetz mike.kravetz@oracle.com Cc: Muchun Song songmuchun@bytedance.com Cc: Oscar Salvador osalvador@suse.de Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/hugetlb.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)

--- a/mm/hugetlb.c~mm-hugetlb-correct-demote-page-offset-logic +++ a/mm/hugetlb.c @@ -3420,6 +3420,7 @@ static int demote_free_huge_page(struct { int i, nid = page_to_nid(page); struct hstate *target_hstate; + struct page *subpage; int rc = 0;

target_hstate = size_to_hstate(PAGE_SIZE << h->demote_order); @@ -3453,15 +3454,16 @@ static int demote_free_huge_page(struct mutex_lock(&target_hstate->resize_lock); for (i = 0; i < pages_per_huge_page(h); i += pages_per_huge_page(target_hstate)) { + subpage = nth_page(page, i); if (hstate_is_gigantic(target_hstate)) - prep_compound_gigantic_page_for_demote(page + i, + prep_compound_gigantic_page_for_demote(subpage, target_hstate->order); else - prep_compound_page(page + i, target_hstate->order); - set_page_private(page + i, 0); - set_page_refcounted(page + i); - prep_new_huge_page(target_hstate, page + i, nid); - put_page(page + i); + prep_compound_page(subpage, target_hstate->order); + set_page_private(subpage, 0); + set_page_refcounted(subpage); + prep_new_huge_page(target_hstate, subpage, nid); + put_page(subpage); } mutex_unlock(&target_hstate->resize_lock);

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Patches currently in -mm which might be from opendmb@gmail.com are

mm-hugetlb-correct-demote-page-offset-logic.patch