Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754456AbZFDE0T (ORCPT ); Thu, 4 Jun 2009 00:26:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751153AbZFDE0L (ORCPT ); Thu, 4 Jun 2009 00:26:11 -0400 Received: from mga03.intel.com ([143.182.124.21]:54640 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750858AbZFDE0L (ORCPT ); Thu, 4 Jun 2009 00:26:11 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.41,302,1241420400"; d="scan'208";a="150463167" Date: Thu, 4 Jun 2009 12:26:03 +0800 From: Wu Fengguang To: Andi Kleen Cc: "akpm@linux-foundation.org" , "npiggin@suse.de" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" Subject: Re: [PATCH] [6/16] HWPOISON: Add various poison checks in mm/memory.c Message-ID: <20090604042603.GA15682@localhost> References: <20090603846.816684333@firstfloor.org> <20090603184639.1933B1D028F@basil.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090603184639.1933B1D028F@basil.firstfloor.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1875 Lines: 58 On Thu, Jun 04, 2009 at 02:46:38AM +0800, Andi Kleen wrote: > > Bail out early when hardware poisoned pages are found in page fault handling. I suspect this patch is also not absolutely necessary: the poisoned page will normally have been isolated already. > Since they are poisoned they should not be mapped freshly into processes, > because that would cause another (potentially deadly) machine check > > This is generally handled in the same way as OOM, just a different > error code is returned to the architecture code. > > Signed-off-by: Andi Kleen > > --- > mm/memory.c | 3 +++ > 1 file changed, 3 insertions(+) > > Index: linux/mm/memory.c > =================================================================== > --- linux.orig/mm/memory.c 2009-06-03 19:36:23.000000000 +0200 > +++ linux/mm/memory.c 2009-06-03 19:36:23.000000000 +0200 > @@ -2797,6 +2797,9 @@ > if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) > return ret; > > + if (unlikely(PageHWPoison(vmf.page))) > + return VM_FAULT_HWPOISON; > + Direct return with locked page could lockup someone later. Either drop this patch or fix it with this check? Thanks, Fengguang --- --- linux.orig/mm/memory.c +++ linux/mm/memory.c @@ -2658,8 +2658,11 @@ static int __do_fault(struct mm_struct * if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) return ret; - if (unlikely(PageHWPoison(vmf.page))) + if (unlikely(PageHWPoison(vmf.page))) { + if (ret & VM_FAULT_LOCKED) + unlock_page(vmf.page); return VM_FAULT_HWPOISON; + } /* * For consistency in subsequent calls, make the faulted page always -- 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/