From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752392AbaGABWR (ORCPT ); Mon, 30 Jun 2014 21:22:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39741 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750742AbaGABWQ (ORCPT ); Mon, 30 Jun 2014 21:22:16 -0400 Date: Mon, 30 Jun 2014 21:21:46 -0400 From: Naoya Horiguchi To: Andi Kleen Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Andi Kleen Subject: Re: [PATCH] hwpoison: Fix race with changing page during offlining v2 Message-ID: <20140701012146.GA23311@nhori.redhat.com> References: <1404174736-17480-1-git-send-email-andi@firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1404174736-17480-1-git-send-email-andi@firstfloor.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 30, 2014 at 05:32:16PM -0700, Andi Kleen wrote: > From: Andi Kleen > > When a hwpoison page is locked it could change state > due to parallel modifications. Check after the lock > if the page is still the same compound page. > > [v2: Removed earlier non LRU check which should be already > covered elsewhere] > > Cc: Naoya Horiguchi > Signed-off-by: Andi Kleen Acked-by: Naoya Horiguchi Is it -stable matter? Maybe 2.6.38+ can profit from this. Thanks, Naoya Horiguchi > --- > mm/memory-failure.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index cd8989c..99e5077 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1168,6 +1168,16 @@ int memory_failure(unsigned long pfn, int trapno, int flags) > lock_page(hpage); > > /* > + * The page could have changed compound pages during the locking. > + * If this happens just bail out. > + */ > + if (compound_head(p) != hpage) { > + action_result(pfn, "different compound page after locking", IGNORED); > + res = -EBUSY; > + goto out; > + } > + > + /* > * We use page flags to determine what action should be taken, but > * the flags can be modified by the error containment action. One > * example is an mlocked page, where PG_mlocked is cleared by > -- > 1.9.3 > > -- > 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 >