From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761814AbXHVJD6 (ORCPT ); Wed, 22 Aug 2007 05:03:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758211AbXHVIxh (ORCPT ); Wed, 22 Aug 2007 04:53:37 -0400 Received: from 1wt.eu ([62.212.114.60]:2114 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758659AbXHVIxd (ORCPT ); Wed, 22 Aug 2007 04:53:33 -0400 From: Willy Tarreau Message-Id: <20070822084029.%N@1wt.eu> References: <20070822083844.%N@1wt.eu> User-Agent: quilt/0.46-1 Date: Wed, 22 Aug 2007 11:39:23 +0200 To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Gurudas Pai , Andrew Morton , Greg Kroah-Hartman , Willy Tarreau Subject: [2.6.20.17 review 39/58] hugetlb: fix race in alloc_fresh_huge_page() Content-Disposition: inline; filename=0039-hugetlb-fix-race-in-alloc_fresh_huge_page.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org That static `nid' index needs locking. Without it we can end up calling alloc_pages_node() with an illegal node ID and the kernel crashes. Acked-by: Gurudas Pai Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- mm/hugetlb.c | 15 +++++++++++---- 1 files changed, 11 insertions(+), 4 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 36db012..7c07eb2 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -101,13 +101,20 @@ static void free_huge_page(struct page *page) static int alloc_fresh_huge_page(void) { - static int nid = 0; + static int prev_nid; struct page *page; - page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, - HUGETLB_PAGE_ORDER); - nid = next_node(nid, node_online_map); + static DEFINE_SPINLOCK(nid_lock); + int nid; + + spin_lock(&nid_lock); + nid = next_node(prev_nid, node_online_map); if (nid == MAX_NUMNODES) nid = first_node(node_online_map); + prev_nid = nid; + spin_unlock(&nid_lock); + + page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, + HUGETLB_PAGE_ORDER); if (page) { set_compound_page_dtor(page, free_huge_page); spin_lock(&hugetlb_lock); -- 1.5.2.5 --