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From:   "Matthew Wilcox (Oracle)" <willy@infradead.org>
To:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc:     "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: [PATCH] mm/hwpoison: Check the subpage, not the head page
Date:   Sun, 30 Jan 2022 01:30:42 +0000
Message-Id: <20220130013042.1906881-1-willy@infradead.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hardware poison is tracked on a per-page basis, not on the head page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/rmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 6a1e8c7f6213..09b08888120e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1553,7 +1553,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		/* Update high watermark before we lower rss */
 		update_hiwater_rss(mm);
 
-		if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
+		if (PageHWPoison(subpage) && !(flags & TTU_IGNORE_HWPOISON)) {
 			pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));
 			if (PageHuge(page)) {
 				hugetlb_count_sub(compound_nr(page), mm);
@@ -1873,7 +1873,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
 			 * memory are supported.
 			 */
 			subpage = page;
-		} else if (PageHWPoison(page)) {
+		} else if (PageHWPoison(subpage)) {
 			pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));
 			if (PageHuge(page)) {
 				hugetlb_count_sub(compound_nr(page), mm);
-- 
2.34.1