Because we reuse the first tail page, if we set PageHWPosion on a
tail page. It indicates that we may set PageHWPoison on a series
of pages. So we need to clear PageHWPoison on the non-error pages.
We use the head[3].mapping to record the real error page index and
clear non-error page PageHWPoison later.

Signed-off-by: Muchun Song <[email protected]>
---
 mm/hugetlb.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 34706cec21ec..8666cedf9a7b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1847,6 +1847,21 @@ static inline void free_gigantic_page_comm(struct hstate 
*h, struct page *page)
 {
        free_gigantic_page(page, huge_page_order(h));
 }
+
+static inline bool subpage_hwpoison(struct page *head, struct page *page)
+{
+       return page_private(head + 4) == page - head;
+}
+
+static inline void set_subpage_hwpoison(struct page *head, struct page *page)
+{
+       set_page_private(head + 4, page - head);
+}
+
+static inline void clear_subpage_hwpoison(struct page *head)
+{
+       set_page_private(head + 4, 0);
+}
 #else
 static inline void hugetlb_vmemmap_init(struct hstate *h)
 {
@@ -1894,6 +1909,19 @@ static inline void free_gigantic_page_comm(struct hstate 
*h, struct page *page)
        free_gigantic_page(page, huge_page_order(h));
        spin_lock(&hugetlb_lock);
 }
+
+static inline bool subpage_hwpoison(struct page *head, struct page *page)
+{
+       return true;
+}
+
+static inline void set_subpage_hwpoison(struct page *head, struct page *page)
+{
+}
+
+static inline void clear_subpage_hwpoison(struct page *head)
+{
+}
 #endif
 
 static void update_and_free_page(struct hstate *h, struct page *page)
@@ -1918,6 +1946,9 @@ static void __free_hugepage(struct hstate *h, struct page 
*page)
                                1 << PG_referenced | 1 << PG_dirty |
                                1 << PG_active | 1 << PG_private |
                                1 << PG_writeback);
+
+               if (PageHWPoison(page + i) && !subpage_hwpoison(page, page + i))
+                       ClearPageHWPoison(page + i);
        }
        VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
        VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
@@ -2107,6 +2138,7 @@ static void prep_new_huge_page(struct hstate *h, struct 
page *page, int nid)
        free_huge_page_vmemmap(h, page);
        /* Must be called before the initialization of @page->lru */
        vmemmap_pgtable_free(h, page);
+       clear_subpage_hwpoison(page);
 
        INIT_LIST_HEAD(&page->lru);
        set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
@@ -2477,6 +2509,7 @@ int dissolve_free_huge_page(struct page *page)
                        SetPageHWPoison(page);
                        ClearPageHWPoison(head);
                }
+               set_subpage_hwpoison(head, page);
                list_del(&head->lru);
                h->free_huge_pages--;
                h->free_huge_pages_node[nid]--;
-- 
2.20.1

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