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 813CC6B0083 for ; Mon, 15 Feb 2010 01:15:42 -0500 (EST) Date: Mon, 15 Feb 2010 17:15:35 +1100 From: Nick Piggin Subject: Re: [PATCH] [4/4] SLAB: Fix node add timer race in cache_reap Message-ID: <20100215061535.GI5723@laptop> References: <20100211953.850854588@firstfloor.org> <20100211205404.085FEB1978@basil.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100211205404.085FEB1978@basil.firstfloor.org> Sender: owner-linux-mm@kvack.org To: Andi Kleen Cc: penberg@cs.helsinki.fi, linux-kernel@vger.kernel.org, linux-mm@kvack.org, haicheng.li@intel.com, rientjes@google.com List-ID: On Thu, Feb 11, 2010 at 09:54:04PM +0100, Andi Kleen wrote: > > cache_reap can run before the node is set up and then reference a NULL > l3 list. Check for this explicitely and just continue. The node > will be eventually set up. How, may I ask? cpuup_prepare in the hotplug notifier should always run before start_cpu_timer. > > Signed-off-by: Andi Kleen > > --- > mm/slab.c | 3 +++ > 1 file changed, 3 insertions(+) > > Index: linux-2.6.32-memhotadd/mm/slab.c > =================================================================== > --- linux-2.6.32-memhotadd.orig/mm/slab.c > +++ linux-2.6.32-memhotadd/mm/slab.c > @@ -4093,6 +4093,9 @@ static void cache_reap(struct work_struc > * we can do some work if the lock was obtained. > */ > l3 = searchp->nodelists[node]; > + /* Note node yet set up */ > + if (!l3) > + break; > > reap_alien(searchp, l3); > > > -- > 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 -- 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