Is your NMI stuck? Well you better catch it! Hey! I’m allowed to make bad jokes. After all, that is why you keep coming back, no?
So to follow up some on our prior NMI issues. It seems that unlike what was stated before, this isn’t specific to resource constraints, x64, or vSMP. In fact, I’ve now seen it happen on any number of configs. After chasing this down with VMware, it seems that there is in fact some kernel funkiness that is going on.
Per VMware KB 1003936:
Some Linux kernels, prior to version 2.6.20, that run on multiple processors have a bug that can cause the kernel to hang. If this occurs, the following message will display:
NMI appears to be stuck.
Red Hat Enterprise Linux 5 is known to have this problem.
There is also the following Red Hat KB which links to a patch. It should be noted, however, that more recent RHEL (and other distro’s) do not seem to have this issue.
Like always, leave me any questions or comments in the comments or on Twitter. Happy Hunting
Edited to fix my spelling error :\