Messages in this thread | | | From | "Alan" <> | Subject | RE: Weird SysRq's during reboot | Date | Thu, 5 Jul 2018 15:02:45 +0100 |
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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' <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
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