From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Subject: mm, hwpoison: do not lock page again when me_huge_page() successfully recovers Currently me_huge_page() temporary unlocks page to perform some actions then locks it again later. My testcase (which calls hard-offline on some tail page in a hugetlb, then accesses the address of the hugetlb range) showed that page allocation code detects this page lock on buddy page and printed out "BUG: Bad page state" message. check_new_page_bad() does not consider a page with __PG_HWPOISON as bad page, so this flag works as kind of filter, but this filtering doesn't work in this case because the "bad page" is not the actual hwpoisoned page. This patch suggests to drop the 2nd page lock to fix the issue. Link: https://lkml.kernel.org/r/20210304064437.962442-1-nao.horiguchi@xxxxxxxxx Fixes: commit 78bb920344b8 ("mm: hwpoison: dissolve in-use hugepage in unrecoverable memory error") Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory-failure.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/memory-failure.c~mm-hwpoison-do-not-lock-page-again-when-me_huge_page-successfully-recovers +++ a/mm/memory-failure.c @@ -834,7 +834,6 @@ static int me_huge_page(struct page *p, page_ref_inc(p); res = MF_RECOVERED; } - lock_page(hpage); } return res; @@ -1290,7 +1289,8 @@ static int memory_failure_hugetlb(unsign res = identify_page_state(pfn, p, page_flags); out: - unlock_page(head); + if (PageLocked(head)) + unlock_page(head); return res; } _
