Debugging hanging libvirt

[Tobias Hofmann (tohofman)]

Hello all,

I have a system with one VM running. After some time the VM needs to be temporarily stopped and started again. This start operation fails and from that point on any virsh command is hanging and does not execute.
This issue is reproducible and I have already figured out that restarting libvirtd resolves this issue. However, I’m now trying to understand why it’s getting stuck in the first place.

I try not to get too much into detail because I think this would be more confusing than it would actually help to understand the problem. In general, I’m wondering what approach you should follow to debug why libvirt gets stuck.
Online I’ve read that you should run this command: `# gdb -batch -p $(pidof libvirtd) -ex 't a a bt f'`. I’ve run that command and attached the output to this mail. However, I have to admit that I have no idea what to do with it.

System related info:

  *   OS: CentOS 7.8.2003
  *   libvirt version: 4.5.0-33

Appreciate any help here!

Thank you!
Tobias

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