From: Naoya Horiguchi naoya.horiguchi@nec.com Subject: mm, hwpoison: add is_free_buddy_page() in HWPoisonHandlable()

commit fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages") changes the return value of __get_hwpoison_page() to retry for transiently unhandlable cases. However, __get_hwpoison_page() currently fails to properly judge buddy pages as handlable, so hard/soft offline for buddy pages always fail as "unhandlable page". This is totally regrettable.

So let's add is_free_buddy_page() in HWPoisonHandlable(), so that __get_hwpoison_page() returns different return values between buddy pages and unhandlable pages as intended.

Link: https://lkml.kernel.org/r/20210909004131.163221-1-naoya.horiguchi@linux.dev Fixes: fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages") Signed-off-by: Naoya Horiguchi naoya.horiguchi@nec.com Acked-by: David Hildenbrand david@redhat.com Reviewed-by: Yang Shi shy828301@gmail.com Cc: Tony Luck tony.luck@intel.com Cc: Oscar Salvador osalvador@suse.de Cc: Mike Kravetz mike.kravetz@oracle.com Cc: Michal Hocko mhocko@suse.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

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

--- a/mm/memory-failure.c~mm-hwpoison-add-is_free_buddy_page-in-hwpoisonhandlable +++ a/mm/memory-failure.c @@ -1126,7 +1126,7 @@ static int page_action(struct page_state */ static inline bool HWPoisonHandlable(struct page *page) { - return PageLRU(page) || __PageMovable(page); + return PageLRU(page) || __PageMovable(page) || is_free_buddy_page(page); }

static int __get_hwpoison_page(struct page *page) _