From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx109.postini.com [74.125.245.109]) by kanga.kvack.org (Postfix) with SMTP id EC78C6B005D for ; Sun, 9 Sep 2012 16:33:46 -0400 (EDT) Message-ID: <504CFD22.3050300@zytor.com> Date: Sun, 09 Sep 2012 13:33:38 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: mtd: kernel BUG at arch/x86/mm/pat.c:279! References: <1340959739.2936.28.camel@lappy> <1347057778.26695.68.camel@sbsiddha-desk.sc.intel.com> <1347062045.26695.82.camel@sbsiddha-desk.sc.intel.com> <504CCA31.2000003@zytor.com> <1347217472.2068.35.camel@shinybook.infradead.org> In-Reply-To: <1347217472.2068.35.camel@shinybook.infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Woodhouse Cc: Linus Torvalds , Suresh Siddha , Sasha Levin , Andrew Morton , "linux-kernel@vger.kernel.org" , linux-mtd@lists.infradead.org, linux-mm , Dave Jones On 09/09/2012 12:04 PM, David Woodhouse wrote: > On Sun, 2012-09-09 at 09:56 -0700, H. Peter Anvin wrote: >> >>> So it should either be start=0xfffffffffffff000 end=0xffffffffffffffff >>> or it should be start=0xfffffffffffff000 len=0x1000. >> >> I would strongly object to the former; that kind of inclusive ranges >> breed a whole class of bugs by themselves. > > Another alternative that avoids overflow issues is to use a PFN rather > than a byte address. > Except as a result of that logic have a bunch of places which either have rounding errors in how they calculate PFNs, or they think they can stick PFNs into 32-bit numbers. :( -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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