Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756289AbYBSS1R (ORCPT ); Tue, 19 Feb 2008 13:27:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752752AbYBSS1E (ORCPT ); Tue, 19 Feb 2008 13:27:04 -0500 Received: from hellhawk.shadowen.org ([80.68.90.175]:2375 "EHLO hellhawk.shadowen.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753288AbYBSS1D (ORCPT ); Tue, 19 Feb 2008 13:27:03 -0500 From: Andy Whitcroft To: Andrew Morton Cc: Adam Litke , Nishanth Aravamudan , William Irwin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] hugetlb: ensure we do not reference a surplus page after handing it to buddy Date: Tue, 19 Feb 2008 18:28:08 -0000 Message-Id: <1203445688.0@pinky> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1401 Lines: 39 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 --- mm/hugetlb.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index cb1b3a7..89e6286 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); } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/