Linux kernel: Uhhuh. NMI received for unknown reason 30

by Vivek Gite · 0 comments

Q. I've upgrade my CentOS / RHEL (Red Hat Enterprise Linux) 4.7 on HP ProLiant DL580 G5 and it is showing unknown NMI errors in the logs:

Uhhuh. NMI received for unknown reason 30.
Dazed and confused, but trying to continue
Do you have a strange power saving mode enabled?

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

How do I fix this error?
A. This is caused when the system is hanging under load. Add any one of the following to you /boot/grub.conf file:

  1. Disable the NMI watchdog by adding "nmi_watchdog=0"
  2. Disable the high precision event timer (HPET) by adding "nohpet"

Open grub.conf, type:
vi grub.conf
Make modification to kernel line as follows:

title Red Hat Enterprise Linux AS (2.6.9-78.0.8.EL)
        root (hd0,0)
        kernel /vmlinuz-2.6.9-78.0.8.EL ro nohpet root=/dev/VolGroup00/LogVol00 nohpet
        initrd /initrd-2.6.9-78.0.8.EL.img

Save and close the file. Reboot the server:
# reboot

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