[patch 07/13] hugetlb: pass head page to remove_hugetlb_page()

From: Naoya Horiguchi <redacted>
Subject: hugetlb: pass head page to remove_hugetlb_page()

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.

Link: https://lkml.kernel.org/r/20210526235257.2769473-1-nao.horiguchi@gmail.com
Fixes: 6eb4e88a6d27 ("hugetlb: create remove_hugetlb_page() to separate functionality")
Signed-off-by: Naoya Horiguchi <redacted>
Reviewed-by: Mike Kravetz <redacted>
Reviewed-by: Muchun Song <redacted>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/hugetlb.c~hugetlb-pass-head-page-to-remove_hugetlb_page
+++ a/mm/hugetlb.c

@@ -1793,7 +1793,7 @@ retry:
 			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);

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