From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 54AB06B00CE for ; Tue, 9 Mar 2010 15:23:32 -0500 (EST) Date: Tue, 9 Mar 2010 12:22:53 -0800 From: Andrew Morton Subject: Re: mm: Do not iterate over NR_CPUS in __zone_pcp_update() Message-Id: <20100309122253.3f3d4a53.akpm@linux-foundation.org> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Thomas Gleixner Cc: LKML , linux-mm@kvack.org, Pekka Enberg , Christoph Lameter List-ID: On Mon, 8 Mar 2010 10:21:04 +0100 (CET) Thomas Gleixner wrote: > __zone_pcp_update() iterates over NR_CPUS instead of limiting the > access to the possible cpus. This might result in access to > uninitialized areas as the per cpu allocator only populates the per > cpu memory for possible cpus. > > Signed-off-by: Thomas Gleixner > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6/mm/page_alloc.c > =================================================================== > --- linux-2.6.orig/mm/page_alloc.c > +++ linux-2.6/mm/page_alloc.c > @@ -3224,7 +3224,7 @@ static int __zone_pcp_update(void *data) > int cpu; > unsigned long batch = zone_batchsize(zone), flags; > > - for (cpu = 0; cpu < NR_CPUS; cpu++) { > + for_each_possible_cpu(cpu) { > struct per_cpu_pageset *pset; > struct per_cpu_pages *pcp; > I'm having trouble working out whether we want to backport this into 2.6.33.x or earlier. Help? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org