From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754326AbYJ2OZx (ORCPT ); Wed, 29 Oct 2008 10:25:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753454AbYJ2OZp (ORCPT ); Wed, 29 Oct 2008 10:25:45 -0400 Received: from mtagate2.de.ibm.com ([195.212.17.162]:60866 "EHLO mtagate2.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753358AbYJ2OZp (ORCPT ); Wed, 29 Oct 2008 10:25:45 -0400 Subject: [PATCH] memory hotplug: fix page_zone() calculation in test_pages_isolated() From: Gerald Schaefer Reply-To: gerald.schaefer@de.ibm.com To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, kamezawa.hiroyu@jp.fujitsu.com, y-goto@jp.fujitsu.com, dave@linux.vnet.ibm.com Content-Type: text/plain Date: Wed, 29 Oct 2008 15:25:30 +0100 Message-Id: <1225290330.10021.7.camel@t60p> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Gerald Schaefer My last bugfix here (adding zone->lock) introduced a new problem: Using page_zone(pfn_to_page(pfn)) to get the zone after the for() loop is wrong. pfn will then be >= end_pfn, which may be in a different zone or not present at all. This may lead to an addressing exception in page_zone() or spin_lock_irqsave(). Now I use __first_valid_page() again after the loop to find a valid page for page_zone(). Signed-off-by: Gerald Schaefer --- mm/page_isolation.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) Index: linux-2.6/mm/page_isolation.c =================================================================== --- linux-2.6.orig/mm/page_isolation.c +++ linux-2.6/mm/page_isolation.c @@ -130,10 +130,11 @@ int test_pages_isolated(unsigned long st if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) break; } - if (pfn < end_pfn) + page = __first_valid_page(start_pfn, end_pfn - start_pfn); + if ((pfn < end_pfn) || !page) return -EBUSY; /* Check all pages are free or Marked as ISOLATED */ - zone = page_zone(pfn_to_page(pfn)); + zone = page_zone(page); spin_lock_irqsave(&zone->lock, flags); ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn); spin_unlock_irqrestore(&zone->lock, flags);