I've been trying to use ChatGPT to get help on actual problems that I
didn't solve by using Internet search, or I wanted a more focused look at
some particular issue. I've started to find it to be a real help -
sometimes - but you have to set it up right, be patient, and keep
shepherding it back to a helpful path.
A few days ago I had a serious problem with one of my Linux virtual
machines. I upgraded the VirtualBox software and rebuilt the guest
additions, but now I couldn't use the bidirectional clipboard or mount the
shared folder. The shared folder is a folder on the host (Windows 10) drive
that can be read and written to by the VM. The bidirectional clipboard
means that the WIndows' clipboard can be shared by the VM (and any other
VMs configured with it). With the clipboard, I could copy code snippets to
the VM and insert Leo nodes that O copied form Leos on Windows. Without
those two features, the VM is isolated.
With the VB community edition, you have to install the "Guest Additions" on
the guest VM to get those features to work. This is routine and I've done
it dozens of times. But now they didn't work.
I'm going to share the transcript of my session with ChatGPT that ended up
with me solving the problem. I'm only going to show you the first bit of
each response because typically it would spit out a lot of steps to follow,
but the first step or two wouldn't work. In the end, an update to the
guest VM had updated the Linux kernel but somehow the guest additions
apparently was trying to install the older version. To confuse matters, the
Distro also includes some version of the GA and which one is being updated
and installed?
At the beginning I give Chat the ground rules. They are important.
Me
-----
This session is about running a linux virtualbox VM guest on a windows 10
host. I am fairly experienced in creating and running virtualbox VMs. You
will respond as an expert in virtualbox operations and you will be concise.
I have a arch-based VM that has been in use for some time. I upgraded
Virtualbox to the newest version, 7.1.x, installed the extension pack as an
admin, and ran the VM. I installed the guest additions apparently
successfully and rebooted the VM. Now each time I log on I get a
notification that the VBox kernel client service is not running. Without
working guest additions, bidirectional cut and paste do not work and I
cannot access shared directories with the host.
What I have tried: reboots, uninstall/reinstall guest additions, and
uninstall/reinstall the virtualbox software on the Windows host. Do you
have any suggestions for restoring normal operations in the VM?
Chat
----
Yes! This issue often happens due to mismatches or missing kernel modules.
Below are steps to restore normal operations in your Arch-based VM.
1. Confirm Kernel Module Compatibility
Ensure that the guest additions kernel modules match your Arch kernel
version.
Inside the VM, run:
bash
uname -r
pacman -Qs virtualbox
Check that the installed VirtualBox Guest modules (virtualbox-guest-utils
or similar) are compatible with the displayed kernel version.
---- much more omitted ---
Me
----
At step two:
modeprobe: ERROR: could not insert 'vboxsf': Protocol error
Chat
-----
The "Protocol error" indicates a problem with the vboxsf kernel module,
usually caused by mismatches between the VirtualBox version, guest
additions, or kernel modules. Let's address it step-by-step.
Steps to Resolve the vboxsf Protocol Error
---- more omitted -----
Me
---
Up through step 4, no change. systemctl status vboxservice has two lines
that are possibly relevant. The error messages are:
1. VBoxDRMClient: already running, exiting
2. automount failed because it couldn't find the mount point for the shared
directory in /media. However, the mount point exists. Its owner and group
are root, so I assume we have a permissions problem here. Not that I, the
user, are already a member of the vboxsf group.
Chat
---
Thank you for the details! Let’s break down the two issues and solve them:
Issue 1: VBoxDRMClient: already running, exiting
This warning suggests that the DRM client is already active. It’s usually
benign and doesn’t affect shared folders, but we can ensure it’s not
interfering.
Solution: Restart the vboxservice to ensure everything is clean:
bash
sudo systemctl restart vboxservice
sudo systemctl status vboxservice
If the warning persists but everything else works, it can be safely ignored
since it’s not likely related to your shared folder issue.
---- more omitted -----
Me
---
step 2 failed to mount with a message "no such device". ls -id permissions
look right: drwxrwx---
Chat
-----
The "no such device" error suggests that the vboxsf kernel module is either
not loaded properly or incompatible with your setup. Let’s address this
step-by-step.
Steps to Resolve the "No Such Device" Error
1. Verify if vboxsf Module is Loaded
Check if the vboxsf module is present:
bash
lsmod | grep vboxsf
---- more omitted -----
Me
---
sudo modprobe vboxsf returns error:
ERROR: could not insert 'vboxsf': Protocol error
Chat
-----
The "Protocol error" with vboxsf typically points to mismatched kernel
modules, guest additions, or permissions issues. Here’s how we can tackle
it methodically:
Step-by-Step Resolution
1. Confirm Kernel and Module Versions are Aligned
Check your running kernel version:
bash
uname -r
Confirm virtualbox-guest-utils and linux-headers versions:
bash
pacman -Q | grep -E 'linux|virtualbox'
---- more omitted -----
Me
---
We need you to reduce the number of steps you output. Remember that I
cannot copy error messages from the VM since that's part of the problem we
are trying to fix. I have to transcribe them by hand.
In the pacman -Q step to check the headers, there appears to be a mismatch.
Linux-headers is the right version but linux-api-headers is not.
Chat
-----
Got it! The mismatched linux-api-headers could be causing the issue. Here's
a concise way to address it:
Fix Kernel Header Mismatch
Update and Synchronize Packages:
bash
sudo pacman -Syu
Reinstall API Headers to Match:
bash
sudo pacman -S linux-api-headers
Rebuild VirtualBox Guest Modules:
bash
sudo dkms autoinstall
sudo modprobe vboxsf
---- more omitted ----
Me
---
no command 'dkms'
Chat
-----
Arch-based systems don't include dkms by default. Let's try this without
dkms:
Fix Mismatch and Rebuild Modules Without DKMS
Ensure All Packages are Up-to-Date:
bash
sudo pacman -Syu
Reinstall VirtualBox Guest Utilities and Headers:
bash
sudo pacman -S virtualbox-guest-utils virtualbox-guest-modules-arch linux-h
---- more omitted ----
Me
---
at step 2: nothing needed to be reinstalled, and:
target not found: virtualbox-guest-modules-arch
Chat
-----
Thanks for your patience! It seems Arch has slightly different ways of
handling VirtualBox modules. Let’s proceed with the correct steps:
1. Install Required VirtualBox Modules
Since virtualbox-guest-modules-arch isn’t available, let’s install the
appropriate packages:
bash
sudo pacman -S virtualbox-guest-utils linux-headers
---- more omitted -----
Me
----
sudo modprobe vboxsf returned the same "Protocol error" message as before.
Chat
-----
Since the Protocol error persists, the issue likely lies with the vboxsf
module itself, possibly due to a version mismatch or incomplete
installation. Let's try a few key targeted steps:
--- more omitted ----
Me
---
the dmesg output produced some interesting lines:
vboxguest: loading out-of-tre module taints kernel.
vboxguest: module verification failed: sigmature and/or key misssing -
tained module
vboxguest: Successfully loaded version 7.0.20 r163906
The version that was "Successfully" loaded, 7.0.20, corresponds to the
previous version of Virtual box, the one that I replaced today with the
later one. I don't see how that could still be around to be loaded.
I think you have been flailing around to much, and that we have to find a
way to zero in on the key problem. I'm thinking that there is a bug in this
new release of VirtualBox, and I'm thinking of trying to downgrade if
possible. Note that I have already uninstalled and reinstalled Virtualbox
on the Windows host. Comments or suggestions? Let's stay focused on a few
simple steps or ideas.
Chat
-----
You're absolutely right—let's focus and zero in on the core issue:
mismatched or leftover guest modules from the previous version.
It looks like the old 7.0.20 guest module is still being loaded, which
conflicts with the newer host VirtualBox version. This mismatch could
explain the errors and Protocol error with vboxsf.
---- [note: this seems to have been the real problem] ----
---- more omitted ---
This should eliminate the version conflict. Let me know how it goes!
Me
---
You said:
Because I can't copy them out of the VM, I could only transcribe a few
lines. I will repeat them:
vboxguest: loading out-of-tre module taints kernel.
vboxguest: module verification failed: sigmature and/or key misssing -
tained module
vboxguest: Successfully loaded version 7.0.20 r163906
Chat
-----
Thanks for the clarification. Based on those messages, here's the issue:
Out-of-tree module: The old version (7.0.20) is being loaded, which
"taints" the kernel (i.e., it's not part of the official kernel tree or its
key is missing).
Module verification failed: This suggests that the wrong or outdated
VirtualBox guest module (vboxguest) is still present on the VM.
The problem is that leftover 7.0.20 modules are interfering with the proper
loading of 7.1.x modules. Let’s focus on fully removing the old version and
ensuring only the latest one is loaded.
Focused Fix: Remove Old Modules and Install New Guest Additions
Step 1: Identify and Remove Old VirtualBox Modules
Check for VirtualBox-related modules:
bash
lsmod | grep vbox
---- more omitted ----
Let me know if this resolves the issue or if anything unexpected happens
along the way.
Me
---
wait. I don't read it that way. I read it that the new version (7.1.2) is
out-of-tree or has an missing signature, and that the old version (7.0.20)
somehow gets loaded. Note that the 7.0.20 guest additions worked when
Virtualbox was also at version 7.0.20. comment.
Chat
-----
You're absolutely correct—this points to a mismatch between the new guest
additions (7.1.x) and the modules that are actually getting loaded
(7.0.20). The key is that 7.0.20 modules are being loaded despite the
attempt to install 7.1.x additions.
This could happen if:
Old modules were not properly removed when upgrading.
Kernel module paths are not updated.
7.1.x guest additions installation failed silently, leaving the old
7.0.20 modules active.
---- more omitted -----
Me
----
I want you to generate fewer code steps. you have been success-oriented
but each step has resulted in failure. In this case, in step 1 modinfo
only reported the current version, 7.1.2. the find command reported two
hits, one for vboxguest.ko and one for vboxguest.ko.zst. comments, please.
Chat
-----
Good observations! Here’s what this tells us:
modinfo reporting version 7.1.2:
This suggests that the correct guest module is present and recognized,
but it's not functioning as expected—possibly due to conflicting remnants
or a mismatch between modules and the running kernel.
find reporting vboxguest.ko and vboxguest.ko.zst:
vboxguest.ko: The decompressed module likely in use.
vboxguest.ko.zst: A compressed version of the same module.
This result means that old modules (like 7.0.20) are likely gone, but we
still see behavior consistent with a version conflict—which points to:
Kernel taint or signature issues from the dmesg log.
Possible failure during the kernel module build when installing the
guest additions.
--- more omitted ----
Me
---
This procedure succeeded. I'm a little puzzled as to why since rcboxadd
had been run previously without fixing the problem. I suppose that we had
cleaned the system of undesired package fragments in our earlier efforts.
Chat
-----
Exactly! The earlier cleanup steps likely resolved leftover
inconsistencies—like outdated modules or configuration mismatches—that were
interfering with the rebuild.
When rcvboxadd setup was run this time, it could finally perform a clean
build without conflicting artifacts from the previous version (7.0.20).
Earlier attempts probably failed silently due to those remnants.
In summary:
Removing old modules and files was critical.
The rebuild command needed a clean slate to work correctly.
Glad to hear it's resolved! Let me know if anything else comes up.
=========== End of transcript ==========
In the future I will know to be sensitive to kernel updates and mismatches
if (more likely when) it happens again. Someone who knows a lot more about
Linux and these various commands could probably have tracked this down much
faster, but I'm not that person.
This session took quite a while and required patience and guidance on my
part, but in the end I didn't have to reinstall the OS and reconfigure
everything. To me this was a good outcome. I also learned some useful
things.
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