4.5-stable review patch. If anyone has any objections, please let me know.
------------------ From: Minchan Kim <[email protected]> commit d7e69488bd04de165667f6bc741c1c0ec6042ab9 upstream. Currently, migration code increses num_poisoned_pages on *failed* migration page as well as successfully migrated one at the trial of memory-failure. It will make the stat wrong. As well, it marks the page as PG_HWPoison even if the migration trial failed. It would mean we cannot recover the corrupted page using memory-failure facility. This patches fixes it. Signed-off-by: Minchan Kim <[email protected]> Reported-by: Vlastimil Babka <[email protected]> Acked-by: Naoya Horiguchi <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/migrate.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/mm/migrate.c +++ b/mm/migrate.c @@ -967,7 +967,13 @@ out: dec_zone_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); /* Soft-offlined page shouldn't go through lru cache list */ - if (reason == MR_MEMORY_FAILURE) { + if (reason == MR_MEMORY_FAILURE && rc == MIGRATEPAGE_SUCCESS) { + /* + * With this release, we free successfully migrated + * page and set PG_HWPoison on just freed page + * intentionally. Although it's rather weird, it's how + * HWPoison flag works at the moment. + */ put_page(page); if (!test_set_page_hwpoison(page)) num_poisoned_pages_inc();
