Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757767AbYGNSmf (ORCPT ); Mon, 14 Jul 2008 14:42:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757262AbYGNSm0 (ORCPT ); Mon, 14 Jul 2008 14:42:26 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:36420 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757261AbYGNSmZ (ORCPT ); Mon, 14 Jul 2008 14:42:25 -0400 Date: Mon, 14 Jul 2008 11:42:01 -0700 (PDT) From: Linus Torvalds To: Andi Kleen cc: Ingo Molnar , Linux Kernel Mailing List , Andrew Morton , Avi Kivity Subject: Re: [git pull] core, x86: make LIST_POISON less deadly In-Reply-To: <8763r8z570.fsf@basil.nowhere.org> Message-ID: References: <20080714144828.GA22666@elte.hu> <20080714151247.GA27145@elte.hu> <8763r8z570.fsf@basil.nowhere.org> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1204 Lines: 37 On Mon, 14 Jul 2008, Andi Kleen wrote: > > The issue is that the kernel cannot detect it (short of running the > KVM x86 emulator on #GP, but surely you're not suggesting that), so it > cannot print something out. Don't be silly. It prints out the oops message. People who cannot see where that oops is, and cannot be bothered to look at the register state aren't going to help _anyway_. In fact, with the 0xdead... sequence, it's going to be *more* obvious than with some almost-kernel 0xffffc.. address, even if it's not showing up in the first line. In other words, your whole argument is pure and utter sh*t. The page fault is _less_ readable than the GP fault. > That is why I suggested using a canonical address. And I disagree. Violently. The whole and ONLY point of poisoning is to get the fault. With the canonical address, you won't get it reliably, and when you do get it, it's not obvious to decode. End of discussion. Linus -- 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/