From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: mm/hwpoison: fix wrong num_poisoned_pages accounting
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 <minchan@xxxxxxxxxx>
Reported-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff -puN mm/migrate.c~mm-hwpoison-fix-wrong-num_poisoned_pages-account mm/migrate.c
--- a/mm/migrate.c~mm-hwpoison-fix-wrong-num_poisoned_pages-account
+++ a/mm/migrate.c
@@ -975,7 +975,13 @@ 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();
_
--
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