From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 01BE25F0001 for ; Tue, 7 Apr 2009 15:03:32 -0400 (EDT) Date: Tue, 7 Apr 2009 21:03:30 +0200 From: Johannes Weiner Subject: Re: [PATCH] [8/16] POISON: Add various poison checks in mm/memory.c Message-ID: <20090407190330.GB3818@cmpxchg.org> References: <20090407509.382219156@firstfloor.org> <20090407151005.4E24B1D046D@basil.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090407151005.4E24B1D046D@basil.firstfloor.org> Sender: owner-linux-mm@kvack.org To: Andi Kleen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org List-ID: On Tue, Apr 07, 2009 at 05:10:05PM +0200, Andi Kleen wrote: > > Bail out early when poisoned pages are found in page fault handling. > Since they are poisoned they should not be mapped freshly > into processes. > > 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 | 7 +++++++ > 1 file changed, 7 insertions(+) > > Index: linux/mm/memory.c > =================================================================== > --- linux.orig/mm/memory.c 2009-04-07 16:39:39.000000000 +0200 > +++ linux/mm/memory.c 2009-04-07 16:39:39.000000000 +0200 > @@ -2560,6 +2560,10 @@ > goto oom; > __SetPageUptodate(page); > > + /* Kludge for now until we take poisoned pages out of the free lists */ > + if (unlikely(PagePoison(page))) > + return VM_FAULT_POISON; > + When memory_failure() hits a page still on the free list (!page_count()) then the get_page() in memory_failure() will trigger a VM_BUG. So either this check is unneeded or it should be get_page_unless_zero() in memory_failure()? -- 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