If hugetlb_vmemmap_optimized is enabled, folio_clear_hugetlb_hwpoison()
called from try_memory_failure_hugetlb() won't transfer HWPoison flag to
subpages while folio's HWPoison flag is cleared. So when trying to free
this hugetlb page into buddy, folio_clear_hugetlb_hwpoison() is not called
to move HWPoison flag from head page to the raw error pages even if now
hugetlb_vmemmap_optimized is cleared. This will results in HWPoisoned page
being used again and raw_hwp_page leak.

Fixes: ac5fcde0a96a ("mm, hwpoison: make unpoison aware of raw error info in hwpoisoned hugepage")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/memory-failure.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index d21ee27ad412..c155122e3c66 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1913,6 +1913,8 @@ void folio_clear_hugetlb_hwpoison(struct folio *folio)
 {
 	if (folio_test_hugetlb_raw_hwp_unreliable(folio))
 		return;
+	if (folio_test_hugetlb_vmemmap_optimized(folio))
+		return;
 	folio_clear_hwpoison(folio);
 	folio_free_raw_hwp(folio, true);
 }
-- 
2.33.0

On Sat, Jul 08, 2023 at 04:57:38PM +0800, Miaohe Lin wrote:
> If hugetlb_vmemmap_optimized is enabled, folio_clear_hugetlb_hwpoison()
> called from try_memory_failure_hugetlb() won't transfer HWPoison flag to
> subpages while folio's HWPoison flag is cleared. So when trying to free
> this hugetlb page into buddy, folio_clear_hugetlb_hwpoison() is not called
> to move HWPoison flag from head page to the raw error pages even if now
> hugetlb_vmemmap_optimized is cleared. This will results in HWPoisoned page
> being used again and raw_hwp_page leak.
> 
> Fixes: ac5fcde0a96a ("mm, hwpoison: make unpoison aware of raw error info in hwpoisoned hugepage")
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>

Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>