From: Andy Whitcroft Date: Sat, 23 Feb 2008 23:23:32 +0000 (-0800) Subject: hugetlb: ensure we do not reference a surplus page after handing it to buddy X-Git-Tag: v2.6.25-rc3~58 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e5df70ab194543522397fa3da8c8f80564a0f7d3;p=linux-2.6 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 --- diff --git a/mm/hugetlb.c b/mm/hugetlb.c index cb1b3a7ecd..89e6286a7f 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); } /*