From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752586AbYJ0RTU (ORCPT ); Mon, 27 Oct 2008 13:19:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751204AbYJ0RTM (ORCPT ); Mon, 27 Oct 2008 13:19:12 -0400 Received: from mtagate2.uk.ibm.com ([194.196.100.162]:42808 "EHLO mtagate2.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750928AbYJ0RTL (ORCPT ); Mon, 27 Oct 2008 13:19:11 -0400 Subject: [PATCH] memory hotplug: fix page_zone() calculation in test_pages_isolated() From: Gerald Schaefer 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 In-Reply-To: <4905F114.3030406@de.ibm.com> References: <4905F114.3030406@de.ibm.com> Content-Type: text/plain Date: Mon, 27 Oct 2008 18:19:09 +0100 Message-Id: <1225127949.20384.6.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-8.el5_2.2) 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);