Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932694AbaJUN3n (ORCPT ); Tue, 21 Oct 2014 09:29:43 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:62414 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932471AbaJUN3l (ORCPT ); Tue, 21 Oct 2014 09:29:41 -0400 Message-ID: <54465FC2.1030106@martingkelly.com> Date: Tue, 21 Oct 2014 06:29:38 -0700 From: Martin Kelly User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.0 MIME-Version: 1.0 To: Thomas Gleixner CC: linux-kernel@vger.kernel.org, x86@kernel.org, mingo@redhat.com, hpa@zytor.com, akpm@linux-foundation.org, rientjes@google.com, david.vrabel@citrix.com, Martin Kelly Subject: Re: [PATCH v2] x86, e820: panic on sanitizing invalid memory map References: <1413859062-26594-1-git-send-email-martin@martingkelly.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/21/2014 01:56 AM, Thomas Gleixner wrote: >> This patch changes the behavior so that sanitize_e820_map is a void >> function. When the provided memory map has length 1 or it is sanitized >> (both ok cases), it returns nothing. If the provided memory map is >> invalid, then it panics. > > So you break wilfully default_machine_specific_memory_setup() and > probably some other places. Are you sure about that? > I was concerned about exactly that kind of breakage, so my first patch merely separated out the return values and added some appropriate error checking: https://lkml.org/lkml/2014/10/13/514 I then asked whether there are valid cases for ignoring an invalid map and continuing on, but I didn't receive a reply, so I took my best guess. It appears I missed some fallback code (default_machine_specific_memory_setup). That said, most cases don't appear to have fallback code and will hit issues later on if the BIOS map is invalid (e.g. Xen). Thomas, do you see any issues with a revision that separates out the return values (0 for a map with 1 entry, -1 for a map with invalid entries) and adds checks in the callers, where appropriate? Thanks, Martin -- 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/