From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id B798220D7649F for ; Wed, 12 Apr 2017 01:40:44 -0700 (PDT) Date: Wed, 12 Apr 2017 16:40:37 +0800 From: Dave Young Subject: Re: KASLR causes intermittent boot failures on some systems Message-ID: <20170412084037.GA3894@dhcp-128-65.nay.redhat.com> References: <20170412082433.GA3546@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20170412082433.GA3546@dhcp-128-65.nay.redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Jeff Moyer Cc: bhe@redhat.com, linux-nvdimm@lists.01.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, mingo@kernel.org, thgarnie@google.com List-ID: On 04/12/17 at 04:24pm, Dave Young wrote: > On 04/07/17 at 10:41am, Jeff Moyer wrote: > > Hi, > > > > commit 021182e52fe01 ("x86/mm: Enable KASLR for physical mapping memory > > regions") causes some of my systems with persistent memory (whether real > > or emulated) to fail to boot with a couple of different crash > > signatures. The first signature is a NMI watchdog lockup of all but 1 > > cpu, which causes much difficulty in extracting useful information from > > the console. The second variant is an invalid paging request, listed > > below. > > > > On some systems, I haven't hit this problem at all. Other systems > > experience a failed boot maybe 20-30% of the time. To reproduce it, > > configure some emulated pmem on your system. You can find directions > > for that here: https://nvdimm.wiki.kernel.org/ > > > > Install ndctl (https://github.com/pmem/ndctl). > > Configure the namespace: > > # ndctl create-namespace -f -e namespace0.0 -m memory > > > > Then just reboot several times (5 should be enough), and hopefully > > you'll hit the issue. > > > > I've attached both my .config and the dmesg output from a successful > > boot at the end of this mail. > > > [snip] > > I did some tests about emulated pmem via memmap=, kdump kernel hangs or > just reboots early during compressing kernel, no clue how to handle it. > Since for kdump kernel kaslr is pointless a workaround is use "nokaslr" > > In Fedora or RHEL, just add "nokaslr" in KDUMP_COMMANDLINE_APPEND > in /etc/sysconfig/kdump > > Can you try if this works? Oops, your problem is normal boot instead of kdump so this is two different problems. Seems we have not met your bug yet.. Thanks Dave _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753570AbdDLIkt (ORCPT ); Wed, 12 Apr 2017 04:40:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43120 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751992AbdDLIko (ORCPT ); Wed, 12 Apr 2017 04:40:44 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com F2D8180494 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=dyoung@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com F2D8180494 Date: Wed, 12 Apr 2017 16:40:37 +0800 From: Dave Young To: Jeff Moyer Cc: thgarnie@google.com, mingo@kernel.org, bhe@redhat.com, dan.j.williams@intel.com, linux-kernel@vger.kernel.org, linux-nvdimm@ml01.01.org, kexec@lists.infradead.org Subject: Re: KASLR causes intermittent boot failures on some systems Message-ID: <20170412084037.GA3894@dhcp-128-65.nay.redhat.com> References: <20170412082433.GA3546@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170412082433.GA3546@dhcp-128-65.nay.redhat.com> User-Agent: Mutt/1.7.1 (2016-10-04) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 12 Apr 2017 08:40:44 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/12/17 at 04:24pm, Dave Young wrote: > On 04/07/17 at 10:41am, Jeff Moyer wrote: > > Hi, > > > > commit 021182e52fe01 ("x86/mm: Enable KASLR for physical mapping memory > > regions") causes some of my systems with persistent memory (whether real > > or emulated) to fail to boot with a couple of different crash > > signatures. The first signature is a NMI watchdog lockup of all but 1 > > cpu, which causes much difficulty in extracting useful information from > > the console. The second variant is an invalid paging request, listed > > below. > > > > On some systems, I haven't hit this problem at all. Other systems > > experience a failed boot maybe 20-30% of the time. To reproduce it, > > configure some emulated pmem on your system. You can find directions > > for that here: https://nvdimm.wiki.kernel.org/ > > > > Install ndctl (https://github.com/pmem/ndctl). > > Configure the namespace: > > # ndctl create-namespace -f -e namespace0.0 -m memory > > > > Then just reboot several times (5 should be enough), and hopefully > > you'll hit the issue. > > > > I've attached both my .config and the dmesg output from a successful > > boot at the end of this mail. > > > [snip] > > I did some tests about emulated pmem via memmap=, kdump kernel hangs or > just reboots early during compressing kernel, no clue how to handle it. > Since for kdump kernel kaslr is pointless a workaround is use "nokaslr" > > In Fedora or RHEL, just add "nokaslr" in KDUMP_COMMANDLINE_APPEND > in /etc/sysconfig/kdump > > Can you try if this works? Oops, your problem is normal boot instead of kdump so this is two different problems. Seems we have not met your bug yet.. Thanks Dave From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cyDpp-0003xp-6d for kexec@lists.infradead.org; Wed, 12 Apr 2017 08:41:06 +0000 Date: Wed, 12 Apr 2017 16:40:37 +0800 From: Dave Young Subject: Re: KASLR causes intermittent boot failures on some systems Message-ID: <20170412084037.GA3894@dhcp-128-65.nay.redhat.com> References: <20170412082433.GA3546@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20170412082433.GA3546@dhcp-128-65.nay.redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Jeff Moyer Cc: bhe@redhat.com, linux-nvdimm@lists.01.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, mingo@kernel.org, dan.j.williams@intel.com, thgarnie@google.com On 04/12/17 at 04:24pm, Dave Young wrote: > On 04/07/17 at 10:41am, Jeff Moyer wrote: > > Hi, > > > > commit 021182e52fe01 ("x86/mm: Enable KASLR for physical mapping memory > > regions") causes some of my systems with persistent memory (whether real > > or emulated) to fail to boot with a couple of different crash > > signatures. The first signature is a NMI watchdog lockup of all but 1 > > cpu, which causes much difficulty in extracting useful information from > > the console. The second variant is an invalid paging request, listed > > below. > > > > On some systems, I haven't hit this problem at all. Other systems > > experience a failed boot maybe 20-30% of the time. To reproduce it, > > configure some emulated pmem on your system. You can find directions > > for that here: https://nvdimm.wiki.kernel.org/ > > > > Install ndctl (https://github.com/pmem/ndctl). > > Configure the namespace: > > # ndctl create-namespace -f -e namespace0.0 -m memory > > > > Then just reboot several times (5 should be enough), and hopefully > > you'll hit the issue. > > > > I've attached both my .config and the dmesg output from a successful > > boot at the end of this mail. > > > [snip] > > I did some tests about emulated pmem via memmap=, kdump kernel hangs or > just reboots early during compressing kernel, no clue how to handle it. > Since for kdump kernel kaslr is pointless a workaround is use "nokaslr" > > In Fedora or RHEL, just add "nokaslr" in KDUMP_COMMANDLINE_APPEND > in /etc/sysconfig/kdump > > Can you try if this works? Oops, your problem is normal boot instead of kdump so this is two different problems. Seems we have not met your bug yet.. Thanks Dave _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec