Learn how to fix the Rmmod Error: “Module kvm is in use by kvm_intel”. Our KVM Support team is here to help you with your questions and concerns.

Rmmod Error: Module kvm is in use by kvm_intel | Degbugging

Recently, one of our customers encountered an error while trying to remove the KVM (Kernel-based Virtual Machine) module.

Rmmod Error: Module kvm is in use by kvm_intel

This error indicates that the `kvm` module is currently being used by another module, specifically `kvm_intel` (or `kvm_amd` for AMD processors), and cannot be unloaded.

Let’s take a look at what our Experts suggest if we run into this issue.

An Overview:

• Why This Error Occurs
• How to Diagnose the Issue
• 1. Check for Running Virtual Machines
• 2. Check Loaded Modules
• 3. Check Services Using KVM
• How to Resolve the Issue
• 1. Stop Virtual Machines
• 2. Stop Dependent Services
• 3. Unload Dependent Modules
• 4. Force Unloading (If Necessary)
• 5. Reboot the System
• How to Prevent the Issue
• Reload Modules Instead of Removing

Why This Error Occurs

The error occurs because the `kvm` module is actively in use, making it impossible to unload without addressing its dependencies. Here are some of the common reasons:

• Virtual machines (VMs) are running and actively using the KVM module.
• Services like libvirt or QEMU are utilizing KVM for managing virtualization workloads.
• Other processes have locked KVM resources, preventing their removal.

Linux prevents unloading a module in use to avoid disrupting dependent processes, ensuring system stability.

How to Diagnose the Issue

1. Check for Running Virtual Machines

To determine if any VMs are active, run:

virsh list –all

If any VMs are running, they will appear in the list. Shut them down to free up the KVM module.

2. Check Loaded Modules

Check if the `kvm` module and its dependencies are loaded:

lsmod | grep kvm

The output might look like this:


kvm_intel XXXXX 0
kvm XXXXX 1 kvm_intel


This indicates:

• `kvm_intel` is loaded and dependent on `kvm`.
• The `kvm` module cannot be removed until `kvm_intel` is unloaded.

3. Check Services Using KVM

Check if services like libvirt or QEMU are active:

sudo systemctl status libvirtd
sudo systemctl status qemu-kvm


If these services are running, they are likely preventing the removal of the KVM module.

How to Resolve the Issue

1. Stop Virtual Machines

Shut down all active VMs:

virsh shutdown vm-name

Verify that all VMs have stopped using:

virsh list –all

2. Stop Dependent Services

Stop any services using the KVM module:


sudo systemctl stop libvirtd
sudo systemctl stop qemu-kvm


3. Unload Dependent Modules

Unload the dependent modules in the correct order. Start with `kvm_intel` (or `kvm_amd` for AMD CPUs) and then unload `kvm`:

sudo rmmod kvm_intel
sudo rmmod kvm


4. Force Unloading (If Necessary)

If the modules refuse to unload and we are confident it is safe to proceed, use the `-f` flag to force removal:

sudo rmmod -f kvm_intel
sudo rmmod -f kvm


Our Expert would like to point out that forcing module removal can destabilize the system or crash running VMs. It is a good idea to use this option only as a last resort and with caution.

5. Reboot the System

If all else fails, rebooting the system can clear the dependencies and reset the module state:

sudo reboot

How to Prevent the Issue

To avoid running into this error in the future, follow these best practices:

• Always check for active processes or services using the KVM module before attempting removal.
• Gracefully shut down VMs and stop related services like libvirt or QEMU before unloading KVM modules.
• Perform module-related actions during planned maintenance windows when no VMs are running.
• Regularly check and document the services and modules using KVM in your environment to ensure a smooth management process.

Reload Modules Instead of Removing

Reloading modules lets us reset their state without requiring a complete removal, minimizing system disruption. We can easily reload modules with these steps:

• Use `modprobe` to unload (`-r`) the module.
• Reload the module immediately after:

  sudo modprobe -r kvm_intel && sudo modprobe kvm_intel

This method ensures a clean reinitialization of the module, especially useful after system updates or kernel patches.

It avoids breaking dependent services like libvirt or QEMU. Additionally, it is less risky than forcefully removing modules.

We can also use tools designed to manage virtualization features dynamically without requiring manual module handling.

For example:

• virt-manager: A graphical tool for managing KVM virtual machines and underlying virtualization configurations.
• Cockpit: A web-based interface for managing Linux servers, including virtualization tasks.

These tools simplify complex tasks such as starting, stopping, or modifying VMs. It also reduces the chances of misconfiguring kernel modules manually.

[Need assistance with a different issue? Our team is available 24/7.]

Conclusion

The Rmmod error “module kvm is in use by kvm_intel”` occurs because the `kvm` module is actively in use, and Linux prevents its removal to maintain system stability. By following the above diagnostic steps and resolutions, we can safely resolve the issue and minimize system disruption. Remember to prioritize proper shutdown procedures and plan ahead for maintenance tasks to prevent similar errors in the future.

In brief, our Support Experts demonstrated how to fix the Rmmod Error: “Module kvm is in use by kvm_intel”.