From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx160.postini.com [74.125.245.160]) by kanga.kvack.org (Postfix) with SMTP id 3B5746B005D for ; Sun, 9 Sep 2012 12:56:38 -0400 (EDT) Message-ID: <504CCA31.2000003@zytor.com> Date: Sun, 09 Sep 2012 09:56:17 -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> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Suresh Siddha , Sasha Levin , Andrew Morton , dwmw2@infradead.org, "linux-kernel@vger.kernel.org" , linux-mtd@lists.infradead.org, linux-mm , Dave Jones On 09/08/2012 12:57 PM, Linus Torvalds wrote: > > Ack. > > Anyway, that means that the BUG_ON() is likely bogus, but so is the > whole calling convention. > > The 4kB range starting at 0xfffffffffffff000 sounds like a *valid* > range, but that requires that we fix the calling convention to not > have that "end" (exclusive) thing. It should either be "end" > (inclusive), or just "len". > On x86, it is definitely NOT a valid range. There is no physical addresses there, and there will never be any. > 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. -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