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Kdump fails on sles10sp2 with message "Uhhuh. NMI received for unknown reason 20"

This document (7001739) is provided subject to the disclaimer at the end of this document.


SUSE Linux Enterprise Server 10 Service Pack 2



Applies to:
HP ProLiant BL685c g1
HP ProLiant DL785 G5
HP ProLiant DL380 G5

Kernel-kdump and related rpm packages installed to sles10sp2 server with kernel.  When admin fires the kdump trigger (through magic key or console) the server console hangs with the following message showing:

Uhhuh. NMI received for unknown reason 20.
Dazed and confused, but trying to continue
Do you have a strange power saving mode enabled?

The server will restart depending on the setting for ASR Timeout.  No kernel core will be present after booting.



Reported to engineering.  A new kernel update will be released with a new option /proc/sys/kernel/panic_on_unrecovered_nmi.  The default value for this is  "0".  Setting this to "1" allows kernel dumping on HP blades.

The fix is in kernel version and later. After the Kernel has been updated, follow the steps below

Edit /etc/sysctl.conf and add the following line:
kernel.panic_on_unrecovered_nmi = 1

Restart the server after making the modifications. You can check if the setting has been effective, with the following command:
 cat /proc/sys/kernel/panic_on_unrecovered_nmi

The above should return the value of 1


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  • Document ID:7001739
  • Creation Date: 09-Mar-2009
  • Modified Date:10-Mar-2021
    • SUSE Linux Enterprise Server

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