[PATCH 4.1 057/202] mm: migrate: hugetlb: putback destination hugepage to active list

[Greg Kroah-Hartman]

4.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>

commit 3aaa76e125c1dd58c9b599baa8c6021896874c12 upstream.

Since commit bcc54222309c ("mm: hugetlb: introduce page_huge_active")
each hugetlb page maintains its active flag to avoid a race condition
betwe= en multiple calls of isolate_huge_page(), but current kernel
doesn't set the f= lag on a hugepage allocated by migration because the
proper putback routine isn= 't called.  This means that users could
still encounter the race referred to by bcc54222309c in this special
case, so this patch fixes it.

Fixes: bcc54222309c ("mm: hugetlb: introduce page_huge_active")
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 mm/migrate.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1062,7 +1062,7 @@ out:
 	if (rc != MIGRATEPAGE_SUCCESS && put_new_page)
 		put_new_page(new_hpage, private);
 	else
-		put_page(new_hpage);
+		putback_active_hugepage(new_hpage);
 
 	if (result) {
 		if (rc)


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