Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965361AbZLQTOT (ORCPT ); Thu, 17 Dec 2009 14:14:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965327AbZLQTOQ (ORCPT ); Thu, 17 Dec 2009 14:14:16 -0500 Received: from us02smtp2.synopsys.com ([198.182.60.77]:58291 "EHLO alvesta.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965319AbZLQTOP (ORCPT ); Thu, 17 Dec 2009 14:14:15 -0500 Date: Thu, 17 Dec 2009 11:14:01 -0800 From: Joe Buck To: Russell King - ARM Linux Cc: Richard Guenther , David Daney , "gcc@gcc.gnu.org" , Jamie Lokier , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH] ARM: Convert BUG() to use unreachable() Message-ID: <20091217191401.GD10707@synopsys.com> References: <1260266138-17684-1-git-send-email-u.kleine-koenig@pengutronix.de> <20091217150120.GD24967@shareable.org> <4B2A65C6.7080009@caviumnetworks.com> <84fc9c000912170917y4b2772d0n47bb4dabc74b91ef@mail.gmail.com> <20091217181718.GA4440@n2100.arm.linux.org.uk> <20091217183517.GC10707@synopsys.com> <20091217190613.GB4440@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091217190613.GB4440@n2100.arm.linux.org.uk> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 955 Lines: 19 On Thu, Dec 17, 2009 at 11:06:13AM -0800, Russell King - ARM Linux wrote: > On Thu, Dec 17, 2009 at 10:35:17AM -0800, Joe Buck wrote: > > Besides, didn't I see a whole bunch of kernel security patches related > > to null pointer dereferences lately? If page 0 can be mapped, you > > suddenly won't get your trap. > > Page 0 can not be mapped on ARM kernels since the late 1990s, and this > protection is independent of the generic kernel. > > Milage may vary on other architectures, but that's not a concern here. I don't understand, though, why you would want to implement a generally useful facility (make the kernel trap so you can do a post-mortem analysis) in a way that's only safe for the ARM port. -- 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/