Thread (10 messages) 10 messages, 3 authors, 2021-01-18
STALE2002d REVIEWED: 5 (4M)
Revisions (5)
  1. v2 [diff vs current]
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  4. v5 [diff vs current]
  5. v6 current

[PATCH v6 5/5] mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active

From: Muchun Song <hidden>
Date: 2021-01-15 12:53:05
Also in: lkml, stable
Subsystem: hugetlb subsystem, memory management, the rest · Maintainers: Muchun Song, Oscar Salvador, Andrew Morton, Linus Torvalds

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.

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: stable@vger.kernel.org
---
 mm/hugetlb.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f2cef3cf1f85..2d671f3743f5 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1360,8 +1360,7 @@ struct hstate *size_to_hstate(unsigned long size)
  */
 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 */
-- 
2.11.0

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