I ran into a weird problem on a freshly installed server today where one of the DomU virtual machines kept locking up with a kernel panic message:
BUG: soft lockup – CPU#1 stuck for 10s!
All of the other Xen DomU virtual machines running on the box were fine, so I was pretty sure it wasn’t a hardware bug. The only possible solutions that I could come up with were
- My somewhat aggressive stripping down of the Dom0 host
- Zimbra (as the Java process was always the one referenced as being stuck
- The kernel module for the R1Soft CDP backup agent that I had installed a few hours ago.
I’ve run Zimbra on a CentOS 5 Xen VM before (although not 5.4 admittedly), so didn’t think that would be the problem (anyway, user land software should never be able to cause a kernel panic – in theory at least ;-))
Again, the other Xen DomU virtual machines were fine, so hopefully the configuration on the Xen Dom0 host machine itself shouldn’t be causing the problem.
Just to be safe, I updated the kernel-xen package from the default 2.6.18-164.el5 to the latest 2.6.18-164.15.1 which was only released a few days ago and doesn’t appear to be on all of the mirrors yet!
With this done and the virtual machine restarted I had to run r1soft-cki to load an updated kernel module for the R1Soft CDP backup agent and the virtual machine has been stable for several hours now. Fingers crossed it stays that way!