From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753111AbYJ0Qtj (ORCPT ); Mon, 27 Oct 2008 12:49:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751782AbYJ0Qtb (ORCPT ); Mon, 27 Oct 2008 12:49:31 -0400 Received: from mtagate2.de.ibm.com ([195.212.17.162]:46844 "EHLO mtagate2.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751517AbYJ0Qta (ORCPT ); Mon, 27 Oct 2008 12:49:30 -0400 Message-ID: <4905F114.3030406@de.ibm.com> Date: Mon, 27 Oct 2008 17:49:24 +0100 From: Gerald Schaefer Reply-To: gerald.schaefer@de.ibm.com User-Agent: Thunderbird 2.0.0.6 (X11/20080104) MIME-Version: 1.0 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 Subject: [PATCH] memory hotplug: fix page_zone() calculation in test_pages_isolated() Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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 pfn_to_page(pfn) to get the zone after the for() loop is wrong. pfn then points to the first pfn after 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(). Using the last valid page that was found inside the for() loop, instead of pfn_to_page(), should fix this. Signed-off-by: Gerald Schaefer --- mm/page_isolation.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) Index: linux-2.6/mm/page_isolation.c =================================================================== --- linux-2.6.orig/mm/page_isolation.c +++ linux-2.6/mm/page_isolation.c @@ -115,7 +115,7 @@ __test_page_isolated_in_pageblock(unsign int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn, flags; - struct page *page; + struct page *page = NULL; struct zone *zone; int ret; @@ -130,10 +130,10 @@ int test_pages_isolated(unsigned long st if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) break; } - if (pfn < end_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);