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From:   Naoya Horiguchi <nao.horiguchi@gmail.com>
To:     linux-mm@kvack.org, Mike Kravetz <mike.kravetz@oracle.com>
Cc:     Michal Hocko <mhocko@suse.com>, Oscar Salvador <osalvador@suse.de>,
        Muchun Song <songmuchun@bytedance.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Hildenbrand <david@redhat.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v1] hugetlb: pass head page to remove_hugetlb_page()
Date:   Thu, 27 May 2021 08:52:57 +0900
Message-Id: <20210526235257.2769473-1-nao.horiguchi@gmail.com>
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From: Naoya Horiguchi <naoya.horiguchi@nec.com>

When memory_failure() or soft_offline_page() is called on a tail page of
some hugetlb page, "BUG: unable to handle page fault" error can be
triggered.

remove_hugetlb_page() dereferences page->lru, so it's assumed that the
page points to a head page, but one of the caller,
dissolve_free_huge_page(), provides remove_hugetlb_page() with 'page'
which could be a tail page.  So pass 'head' to it, instead.

Fixes: 6eb4e88a6d27 ("hugetlb: create remove_hugetlb_page() to separate functionality")
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
---
 mm/hugetlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git v5.13-rc3/mm/hugetlb.c v5.13-rc3_patched/mm/hugetlb.c
index 95918f410c0f..470f7b5b437e 100644
--- v5.13-rc3/mm/hugetlb.c
+++ v5.13-rc3_patched/mm/hugetlb.c
@@ -1793,7 +1793,7 @@ int dissolve_free_huge_page(struct page *page)
 			SetPageHWPoison(page);
 			ClearPageHWPoison(head);
 		}
-		remove_hugetlb_page(h, page, false);
+		remove_hugetlb_page(h, head, false);
 		h->max_huge_pages--;
 		spin_unlock_irq(&hugetlb_lock);
 		update_and_free_page(h, head);
-- 
2.25.1