From e5df70ab194543522397fa3da8c8f80564a0f7d3 Mon Sep 17 00:00:00 2001 From: Andy Whitcroft Date: Sat, 23 Feb 2008 15:23:32 -0800 Subject: [PATCH] hugetlb: ensure we do not reference a surplus page after handing it to buddy When we free a page via free_huge_page and we detect that we are in surplus the page will be returned to the buddy. After this we no longer own the page. However at the end free_huge_page we clear out our mapping pointer from page private. Even where the page is not a surplus we free the page to the hugepage pool, drop the pool locks and then clear page private. In either case the page may have been reallocated. BAD. Make sure we clear out page private before we free the page. Signed-off-by: Andy Whitcroft Acked-by: Adam Litke Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index cb1b3a7ecdfc..89e6286a7f57 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -120,6 +120,7 @@ static void free_huge_page(struct page *page) struct address_space *mapping; mapping = (struct address_space *) page_private(page); + set_page_private(page, 0); BUG_ON(page_count(page)); INIT_LIST_HEAD(&page->lru); @@ -134,7 +135,6 @@ static void free_huge_page(struct page *page) spin_unlock(&hugetlb_lock); if (mapping) hugetlb_put_quota(mapping, 1); - set_page_private(page, 0); } /* -- 2.39.5