Questions and Answers : Unix/Linux : ubuntu 25.04 tasks won't run
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Toby Broom
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Message 51889 - Posted: 17 May 2025, 12:39:46 UTC

I just upgraded to 25.04 and there was an issue with VirtualBox:

VBoxManage: error: VirtualBox can't enable the AMD-V extension. Please disable the KVM kernel extension, recompile your kernel and reboot (VERR_SVM_IN_USE)

there was a fix here:

https://superuser.com/questions/1845776/virtualbox-cant-operate-in-vmx-mode
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Dave

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Message 51910 - Posted: 25 May 2025, 20:00:19 UTC - in response to Message 51889.  

Thanks. I found another page with the
sudo modprobe -r kvm_amd
but it had a different file to modify and a different line to add for a permanent fix. I shall try the one from that link.

Really the kernel developers and the VBox people should get together to sort this out so users don't need to do this.
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Saturn911

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Message 51913 - Posted: 26 May 2025, 18:07:32 UTC - in response to Message 51889.  

Have you tried "module_blacklist" in your kernel parameters?
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Dave

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Message 51914 - Posted: 26 May 2025, 20:19:25 UTC - in response to Message 51913.  

Have you tried "module_blacklist" in your kernel parameters?
I have done that now. Thanks. I haven't tried a reboot to check it yet. I wonder if it would be worth putting out a push notification on BOINC aimed at Linux users as I can see quite a few work units there are at least one or two failures because of VBox not starting just on work units where I have had tasks from. I know my way around a terminal to some extent but there will be a lot out there who don't.
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William Albert

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Message 52053 - Posted: 29 Jul 2025, 20:07:56 UTC
Last modified: 29 Jul 2025, 20:20:58 UTC

Ubuntu 24.04 HWE recently upgraded to Linux kernel 6.14, and started experiencing similar issues.

This is caused by a change in behavior starting with Linux kernel 6.12 on when KVM initiates the processor's virtualization support. Older kernels initialized virtualization extensions on use -- kernel 6.12 and onward initialize them when the KVM modules are loaded (even if the KVM modules then sit idle and are never actually used).

I didn't want to solve this by blacklisting the KVM modules (as is the common solution if you do a web search), so I reverted to the previous initialization behavior with the following "modprobe" conf file:

# /etc/modprobe.d/virtualbox-no-kvm.conf
#
# In kernel 6.12, KVM initializes virtualization on module loading by default.
# This prevents VirtualBox VMs from starting.
#
# In order to avoid this, either add "kvm.enable_virt_at_load=0" parameter
# into kernel command line or unload corresponding kvm_XXX module.

options kvm enable_virt_at_load=0


The change should take effect on unloading/reloading the KVM kernel modules, or by rebooting (my testing was with the latter).

To verify that things are working properly:

# All commands tested with VirtualBox 7.1.12, but should work with earlier versions

# Create a simple VM. This will always succeed unless your VirtualBox install is broken.
VBoxManage createvm --name "TestVM" --ostype "Linux_64" --register

# Start the VM.
#
# If VirtualBox is working, the VM should start successfully (or fail with an error about
# no bootable media, which is a success for our purposes).
#
# If your CPU doesn't have working hardware virtualization support, or KVM has
# initialized your CPU's hardware virtualization, this will fail with an error about
# your CPU's virtualization extensions being unavailable.
VBoxManage startvm "TestVM" --type headless

# Stop the VM (if it started successfully)
VBoxManage controlvm "TestVM" poweroff

# Clean up the VM
VBoxManage unregistervm "TestVM" --delete
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Questions and Answers : Unix/Linux : ubuntu 25.04 tasks won't run


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