[PATCH v1] mm: bad_page() checks bad_flags instead of page->flags for hwpoison page

[Naoya Horiguchi]

There's a race window between checking page->flags and unpoisoning, which
taints kernel with "BUG: Bad page state". That's overkill. It's safer to
use bad_flags to detect hwpoisoned page.

Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
 mm/page_alloc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git tmp/mm/page_alloc.c tmp_patched/mm/page_alloc.c
index 5b269bc..4e0fa37 100644
--- tmp/mm/page_alloc.c
+++ tmp_patched/mm/page_alloc.c
@@ -522,8 +522,8 @@ static void bad_page(struct page *page, const char *reason,
 	static unsigned long nr_shown;
 	static unsigned long nr_unshown;
 
-	/* Don't complain about poisoned pages */
-	if (PageHWPoison(page)) {
+	/* Don't complain about hwpoisoned pages */
+	if (bad_flags == __PG_HWPOISON) {
 		page_mapcount_reset(page); /* remove PageBuddy */
 		return;
 	}
-- 
2.7.0