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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 33FD9C6778C for ; Thu, 5 Jul 2018 14:02:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94F0624073 for ; Thu, 5 Jul 2018 14:02:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94F0624073 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bytehouse.co.uk 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 S1753749AbeGEOCv (ORCPT ); Thu, 5 Jul 2018 10:02:51 -0400 Received: from mail.tristarwebsolutions.co.uk ([188.191.154.26]:62508 "EHLO mail.tristarsupport.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753439AbeGEOCu (ORCPT ); Thu, 5 Jul 2018 10:02:50 -0400 Received: from BytehousePC01 ([192.168.171.41]) by mail.tristarsupport.co.uk (IceWarp 11.3.1.6 x64) with ASMTP (SSL) id 201807051502390312 for ; Thu, 05 Jul 2018 15:02:39 +0100 From: "Alan" To: References: In-Reply-To: Subject: RE: Weird SysRq's during reboot Date: Thu, 5 Jul 2018 15:02:45 +0100 Message-ID: <139f01d41468$dbc51e70$934f5b50$@bytehouse.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 15.0 Thread-Index: AQG6EQ/zArd5xdEmYK+HDNePgbjSxqS0rb1w Content-Language: en-gb Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Panic over. It seems that my OnApp control server, when it loses contact with a compute node, sends an snmptrap command to force a reboot of that node. The trap script on the server uses sysrq-trigger, first "s", then "u", then "b". Please accept my apologies if you wasted any time on this. Regards, Alan Griffiths Bytehouse -----Original Message----- From: Alan [mailto:alan@bytehouse.co.uk] Sent: 05 July 2018 11:19 To: 'linux-kernel@vger.kernel.org' Subject: Weird SysRq's during reboot Hello everyone, this is my first time posting to this list so please be gentle. I have a server, hardware spec: HP DL360p G8 2 x Intel Xeon E5-2620 Hex-Core 2GHz processors 150GB Ram Embedded HP Ethernet 1Gb 4-port 331FLR Adapter Embedded Smart Array P420i Controller PCI-E Slot 1 HP Ethernet 10Gb 2-port 530SFP+ Adapter which I am trying to configure as an OnApp compute engine. Recently I have seen the following weird behaviour: 1. Login on the server as root 2. Enter a 'shutdown -r now' command 3. Watch the reboot on the iLO console 4. System reboots except that right at the end, after the login prompt appears on the console, I see: SysRq: Emergency Sync Emergency Sync complete SysRq : Emergency Remount R/O And then the system reboots again. 5. The second reboot always works without the SysRq. Looking in /var/log/messages I see, just prior to the second reboot (*): Jul 5 10:30:17 hv08 kernel: Ebtables v2.0 registered Jul 5 10:30:17 hv08 kernel: Bridge firewalling registered Jul 5 10:30:17 hv08 kernel: arp_tables: (C) 2002 David S. Miller Jul 5 10:30:18 hv08 kernel: lo: Disabled Privacy Extensions * Jul 5 10:30:27 hv08 kernel: SysRq : Emergency Sync * Jul 5 10:30:27 hv08 kernel: Emergency Sync complete * Jul 5 10:30:28 hv08 kernel: SysRq : Emergency Remount R/O Jul 5 10:33:43 hv08 kernel: imklog 5.8.10, log source = /proc/kmsg started. Jul 5 10:33:43 hv08 rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="2491" x-info="http://www.rsyslog.com"] start Jul 5 10:33:43 hv08 kernel: Initializing cgroup subsys cpuset Jul 5 10:33:43 hv08 kernel: Initializing cgroup subsys cpu Jul 5 10:33:43 hv08 kernel: Linux version 2.6.32-696.30.1.el6.x86_64 (mockbuild@c1bl.rdu2.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-18) (GCC) ) #1 SMP Tue May 22 03:28:18 UTC 2018 Jul 5 10:33:43 hv08 kernel: Command line: ro root=UUID=eafc533f-c5cb-4c89-bc0d-33125ab7f9d9 nomodeset rd_NO_LUKS KEYBOARDTYPE=pc KEYTABLE=uk LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crash kernel=auto rd_NO_LVM rd_NO_DM rhgb quiet I have tried booting the 2.6.32-696.28.1.el6.x86_64 and the 2.6.32-696.el6.x86_64 kernels with the same result. The problem does not occur if I boot from the Centos 6.9 liveDVD iso which also uses kernel version 2.6.32-696.el6.x86_64. So, I am hoping someone here can answer any of these questions for me: A. What have I done to make this happen? B. Is there a way I can fix it? C. If not is there some other way to stop it happening? Thank you for taking the time to read this email. I shall look forward to hearing from you. Please CC me on any replies. Regards, Alan Griffiths Bytehouse