+ mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch added to -mm tree

The patch titled
     Subject: mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active
has been added to the -mm tree.  Its filename is
     mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch

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------------------------------------------------------
From: Muchun Song <redacted>
Subject: mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active

The page_huge_active() can be called from scan_movable_pages() which
do not hold a reference count to the HugeTLB page. So when we call
page_huge_active() from scan_movable_pages(), the HugeTLB page can
be freed parallel. Then we will trigger a BUG_ON which is in the
page_huge_active() when CONFIG_DEBUG_VM is enabled. Just remove the
VM_BUG_ON_PAGE.

Link: https://lkml.kernel.org/r/20210110124017.86750-7-songmuchun@bytedance.com
Fixes: 7e1f049efb86 ("mm: hugetlb: cleanup using paeg_huge_active()")
Signed-off-by: Muchun Song <redacted>
Reviewed-by: Mike Kravetz <redacted>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <redacted>
Cc: Andi Kleen <redacted>
Cc: <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/mm/hugetlb.c~mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active
+++ a/mm/hugetlb.c

@@ -1361,8 +1361,7 @@ struct hstate *size_to_hstate(unsigned l
  */
 bool page_huge_active(struct page *page)
 {
-	VM_BUG_ON_PAGE(!PageHuge(page), page);
-	return PageHead(page) && PagePrivate(&page[1]);
+	return PageHeadHuge(page) && PagePrivate(&page[1]);
 }
 
 /* never called for tail page */

_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-hugetlbfs-fix-cannot-migrate-the-fallocated-hugetlb-page.patch
mm-hugetlb-fix-a-race-between-freeing-and-dissolving-the-page.patch
mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch
mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch
mm-memcontrol-optimize-per-lruvec-stats-counter-memory-usage.patch
mm-memcontrol-fix-nr_anon_thps-accounting-in-charge-moving.patch
mm-memcontrol-convert-nr_anon_thps-account-to-pages.patch
mm-memcontrol-convert-nr_file_thps-account-to-pages.patch
mm-memcontrol-convert-nr_shmem_thps-account-to-pages.patch
mm-memcontrol-convert-nr_shmem_pmdmapped-account-to-pages.patch
mm-memcontrol-convert-nr_file_pmdmapped-account-to-pages.patch
mm-memcontrol-make-the-slab-calculation-consistent.patch
mm-migrate-do-not-migrate-hugetlb-page-whose-refcount-is-one.patch
mm-hugetlb-add-return-eagain-for-dissolve_free_huge_page.patch