From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDA24C46464 for ; Thu, 9 Aug 2018 07:33:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C11621A38 for ; Thu, 9 Aug 2018 07:33:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C11621A38 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gmx.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729251AbeHIJ5a (ORCPT ); Thu, 9 Aug 2018 05:57:30 -0400 Received: from mout.gmx.net ([212.227.17.22]:33297 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727371AbeHIJ5a (ORCPT ); Thu, 9 Aug 2018 05:57:30 -0400 Received: from homer.simpson.net ([185.221.149.218]) by mail.gmx.com (mrgmx103 [212.227.17.168]) with ESMTPSA (Nemesis) id 0Le69A-1gHCNz3EJ2-00pxcS; Thu, 09 Aug 2018 09:33:31 +0200 Message-ID: <1533800010.5087.71.camel@gmx.de> Subject: Re: [PATCH] x86, kdump: Fix efi=noruntime NULL pointer dereference From: Mike Galbraith To: Dave Young Cc: Baoquan He , Sebastian Andrzej Siewior , lkml , kexec@lists.infradead.org Date: Thu, 09 Aug 2018 09:33:30 +0200 In-Reply-To: <20180809042153.GA4377@dhcp-128-65.nay.redhat.com> References: <1533737025.4936.3.camel@gmx.de> <20180809042153.GA4377@dhcp-128-65.nay.redhat.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K1:FSmBjftEw302nboHY0idqCmA4IVMNl6D4ZILbrG5Zxstm0yMX/X +N9ltjDtNfN8BXJaZPV3j9FiRCe84O0i1uw0JlqNM3khlBDtb7RL0TdoHgRQZ42vcf9s0gw Q9O3cxUnn9R1ZghSvyoMymiJM5ptJ3kFg7pvpMzmw3Ne5NV2PlLATEZVl/xeWgJ2f3pXA/T Z7xePfd1rYVn5wHsbasPw== X-UI-Out-Filterresults: notjunk:1;V01:K0:KZN4Er//DNY=:8aWCq/tEtvK9vRuihPTi4B VXKZVVejccB4/ml/6/wVTRQzFYd3PztURWWY43KTe2c7fd8UlcF1rXDTGpgmcD20YuLmpoSHU SxIGOQ0oz9Sa0VzZ6tl4Z8VjEfRJmSAGZvq4XxXxVcMldauPKquVEhz39p+4jrOCG1J322GJI vLymc6vXBr6+/t7vry34NtxJ7HhL5pK6H0nUzxYAdqVR/GzvwybkWiVM/Dh87tp09dxMwS2Mp axR8t7yteu8M2675aO+1dZbuwu5PP/4FnD+zmCMShafop0D+8ryOp/k4ARgWZ0yaEQjMPow3x rZiuMIYTF8GnB0M/AerVlK1rDkVj/gfJV/vdIG//Ju8+6Uq9qR+WyzxqcEBr3ZGFzXtXdA/+I 6C+HmELjMeyuHtaRrxgroDsHQv9qgUEirfXLaWjoZ0hwYrH/fPUIpayFnzMJUHgS9KJyBSGoq LptAisphiIvEnKPrhYTzLy0R54JcwPsnknT8IP1NgfDehgM/0lzB3dbsbf3AqMKrBpwD8aq+2 XY23LB15DFOKNTQTmToBi7RgJ//UH0bp5jGwXVovTm5vAMK3HTJhp+hxllahStjcPJPkJbuu6 gP61UngKMeax6snKH6XqxKfOv7Hw3w2TteCN/wDhRO1KdqdA1lzRtxU3ubH0Vc73dsEs2Vf3x yeOCtitSdsLZmGZUYoIyBwSiyYddoF+wYS2a/9OvD33qOXJqhEXCM6czcN4K0wfEmALdnJiuw g/Kq3xGTORLYu4mxOg8q7OQYpuRtfzYZEw/G8OIoU7p8xEX2WaVGzshSKGWz7PgGnpmo2oMvT E1ChKdT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2018-08-09 at 12:21 +0800, Dave Young wrote: > Hi Mike, > > Thanks for the patch! > On 08/08/18 at 04:03pm, Mike Galbraith wrote: > > When booting with efi=noruntime, we call efi_runtime_map_copy() while > > loading the kdump kernel, and trip over a NULL efi.memmap.map. Avoid > > that and a useless allocation when the only mapping we can use (1:1) > > is not available. > > At first glance, efi_get_runtime_map_size should return 0 in case > noruntime. What efi does internally at unmap time is to leave everything except efi.mmap.map untouched, setting it to NULL and turning off EFI_MEMMAP, rendering efi.mmap.map accessors useless/unsafe without first checking EFI_MEMMAP. -Mike