Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751984AbdHGNSC (ORCPT ); Mon, 7 Aug 2017 09:18:02 -0400 Received: from mail-it0-f47.google.com ([209.85.214.47]:36232 "EHLO mail-it0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751789AbdHGNSB (ORCPT ); Mon, 7 Aug 2017 09:18:01 -0400 MIME-Version: 1.0 In-Reply-To: <20170807131608.GA18817@arm.com> References: <1502103886-19725-1-git-send-email-miles.chen@mediatek.com> <20170807131608.GA18817@arm.com> From: Ard Biesheuvel Date: Mon, 7 Aug 2017 14:18:00 +0100 Message-ID: Subject: Re: [PATCH] arm64: correct modules range of kernel virtual memory layout To: Will Deacon Cc: Miles Chen , Catalin Marinas , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1451 Lines: 35 On 7 August 2017 at 14:16, Will Deacon wrote: > On Mon, Aug 07, 2017 at 07:04:46PM +0800, Miles Chen wrote: >> The commit f80fb3a3d508 ("arm64: add support for kernel ASLR") >> moved module virtual address to >> [module_alloc_base, module_alloc_base + MODULES_VSIZE). >> >> Display module information of the virtual kernel >> memory layout by using module_alloc_base. >> >> testing output: >> 1) Current implementation: >> Virtual kernel memory layout: >> modules : 0xffffff8000000000 - 0xffffff8008000000 ( 128 MB) >> 2) this patch + KASLR: >> Virtual kernel memory layout: >> modules : 0xffffff8000560000 - 0xffffff8008560000 ( 128 MB) >> 3) this patch + KASLR and a dummy seed: >> Virtual kernel memory layout: >> modules : 0xffffffa7df637000 - 0xffffffa7e7637000 ( 128 MB) >> >> Signed-off-by: Miles Chen >> --- >> arch/arm64/mm/init.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) > > Does this mean the modules code in our pt dumper is busted > (arch/arm64/mm/dump.c)? Also, what about KASAN, which uses these addresses > too (in kasan_init)? Should we just remove MODULES_VADDR and MODULES_END > altogether? > I don't think we need this patch. The 'module' line simply prints the VA region that is reserved for modules. The fact that we end up putting them elsewhere when running randomized does not necessarily mean this line should reflect that.