VMware Cloud Community
ianpasco
Contributor
Contributor

Does the HungVM - Send_NMI_To_Guest works for Linux guest OS?

Hello,

Does the HungVM - Send_NMI_To_Guest works for Linux guest OS?

Is there any dependencies such as drivers or VMware tools that is required to make it function on specific OS.

The below article does not articulate how this tool works and if it only works on Windows guest OS or also on other Linux OS?

https://kb.vmware.com/s/article/2149185.

 

Best regards,

Labels (4)
Reply
0 Kudos
3 Replies
vbondzio
VMware Employee
VMware Employee

Yes, the (virtual) CPU receiving an NMI is understood by pretty much any guest OS.

You don't have to use the UI to test this either, you can use:

vmdumper WID nmi

directly on the ESXi host (via SSH). You can get the WID of a VM via:

vmdumper -l

(or use e.g. this script that lists all kinds of IDs for running VMs: https://github.com/vbondzio/sowasvonunsupported/blob/master/vmid2name.sh

Reply
0 Kudos
ianpasco
Contributor
Contributor

Thanks for the response.

Yes I tried using the CLI as well.

vmdumper and vm-support.

https://kb.vmware.com/s/article/2149185

the following messages appeared in Linux Guest OS messages

> Jan 27 06:32:07 server04 kernel: Uhhuh. NMI received for unknown reason 30 on CPU 0. ★
> Jan 27 06:32:07 server04 kernel: Do you have a strange power saving mode enabled?
> Jan 27 06:32:07 server04 kernel: Dazed and confused, but trying to continue

It appears that the Linux OS is not configured properly.

Must set the following parameter setting in Linux OS /etc/sysctl.conf to enable panic from NMI.

kernel.unknown_nmi_panic=1

 

Reply
0 Kudos
vbondzio
VMware Employee
VMware Employee

Ah yes, you have to enable panic on NMI (in this case unknown), there are more kernel related panic settings you might want to consider when troubleshooting your system. If this is a first occurrence hang without that configured and you want to get the core dump, you can also just suspend the VM in its hung state and convert the vmsn file via vmss2core.

Reply
0 Kudos