From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754620AbYJ2Rzc (ORCPT ); Wed, 29 Oct 2008 13:55:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751865AbYJ2RzX (ORCPT ); Wed, 29 Oct 2008 13:55:23 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:35355 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993AbYJ2RzX (ORCPT ); Wed, 29 Oct 2008 13:55:23 -0400 Message-ID: <4908A392.1060401@austin.ibm.com> Date: Wed, 29 Oct 2008 12:55:30 -0500 From: Nathan Fontenot User-Agent: Thunderbird 2.0.0.17 (X11/20080925) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: Badari Pulavarty Subject: Re: [PATCH] Use correct page frame number to grab page zone lock References: <49089D46.1090609@austin.ibm.com> In-Reply-To: <49089D46.1090609@austin.ibm.com> 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 Disregard. It appears that Gerald Schaefer submitted a patch to fix this already. http://lkml.org/lkml/2008/10/29/142 -Nathan Nathan Fontenot wrote: > There are situations in which the 'pfn' variable used to calculate the > page zone can be invalid. One case is in the hotplug memory remove path > where we are trying to remove memory the last valid page frame for the > system. Passing an invalid page frame number to the pfn_to_page() macro > will cause the system to oops. > > Additionally I think this also solves an issue where we may be grabbing > the wrong zone->lock. This would occur when 'pfn' refers to a page > frame beyond what we are examining and lies in a different zone. > > Using the starting page frame number passed in appears to resolve > both of these issues. This patch also removes the redundant > initialization of 'pfn', it is set explicitly and then again in the for > loop. > > > Signed-off-by: Nathan Fontenot > --- > > Index: linux-2.6/mm/page_isolation.c > =================================================================== > --- linux-2.6.orig/mm/page_isolation.c 2008-10-13 12:00:46.000000000 > -0500 > +++ linux-2.6/mm/page_isolation.c 2008-10-29 11:18:39.000000000 -0500 > @@ -119,7 +119,6 @@ > struct zone *zone; > int ret; > > - pfn = start_pfn; > /* > * Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page > * is not aligned to pageblock_nr_pages. > @@ -133,7 +132,7 @@ > if (pfn < end_pfn) > return -EBUSY; > /* Check all pages are free or Marked as ISOLATED */ > - zone = page_zone(pfn_to_page(pfn)); > + zone = page_zone(pfn_to_page(start_pfn)); > spin_lock_irqsave(&zone->lock, flags); > ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn); > spin_unlock_irqrestore(&zone->lock, flags); > -- > 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/