Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936613AbdDSPHP (ORCPT ); Wed, 19 Apr 2017 11:07:15 -0400 Received: from mail-io0-f182.google.com ([209.85.223.182]:33627 "EHLO mail-io0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936436AbdDSO44 (ORCPT ); Wed, 19 Apr 2017 10:56:56 -0400 MIME-Version: 1.0 In-Reply-To: References: <20170419133630.GA2311@x1> From: Thomas Garnier Date: Wed, 19 Apr 2017 07:56:36 -0700 Message-ID: Subject: Re: KASLR causes intermittent boot failures on some systems To: Dan Williams Cc: Baoquan He , Jeff Moyer , Ingo Molnar , LKML , "linux-nvdimm@lists.01.org" 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: 683 Lines: 23 On Wed, Apr 19, 2017 at 7:34 AM, Dan Williams wrote: > Does the randomization ever cross a pgd boundary? Yes, it can cross a pgd boundary. The original physical memory mapping might as well but you would need almost 550Gb of memory. > > These crashes look very similar to the crashes caused by > arch_add_memory() racing itself. This issue was fixed in: > > f931ab479dd2 mm: fix devm_memremap_pages crash, use > mem_hotplug_{begin, done} > > ...but that only helps users that call mem_hotplug_begin() to prevent > concurrent updates. > It could be related to page table changes done concurrently or just done with certain expectations. -- Thomas