Commit b3b3a99c authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds

mm/migrate: check-before-clear PageSwapCache

With the page flag sanitization patchset, an invalid usage of
ClearPageSwapCache() is detected in migration_page_copy().
migrate_page_copy() is shared by both normal and hugepage (both thp and
hugetlb) code path, so let's check PageSwapCache() and clear it if it's
set to avoid misuse of the invalid clear operation.
Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8d63d99a
......@@ -537,7 +537,8 @@ void migrate_page_copy(struct page *newpage, struct page *page)
* Please do not reorder this without considering how mm/ksm.c's
* get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache().
*/
ClearPageSwapCache(page);
if (PageSwapCache(page))
ClearPageSwapCache(page);
ClearPagePrivate(page);
set_page_private(page, 0);
......
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