fstab error on mounted VHD drive

[tamasbencze]

Windows Version

Microsoft Windows [Version 10.0.26200.7462]

WSL Version

2.5.10

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

6.6.87.2-microsoft-standard-WSL2

Distro Version

RedHat 9.7

Other Software

No response

Repro Steps

wsl --mount --partition 1 --type ext4 --vhd C:\wsldata\wsldata.vhdx --name wsldata

in fstab

UUID=3a732601-db77-44f8-8149-cfede85cceb6 /mnt/wsl/wsldata ext4 defaults 0 0
/mnt/wsl/wsldata/home/developer /home/developer none bind 0 0

Expected Behavior

No error for mounted data drive

Actual Behavior

Dec 16 08:28:46 PBD-IT-WL-rOMw1 mount:
Dec 16 08:28:46 PBD-IT-WL-rOMw1 /mnt/wsl/wsldata: mount point does not exist.
Dec 16 08:28:46 PBD-IT-WL-rOMw1 unknown:
Dec 16 08:28:46 PBD-IT-WL-rOMw1 mount:
Dec 16 08:28:46 PBD-IT-WL-rOMw1 /home/developer: special device /mnt/wsl/wsldata/home/developer does not exist.
Dec 16 08:28:46 PBD-IT-WL-rOMw1 unknown:
Dec 16 08:28:46 PBD-IT-WL-rOMw1 unknown: WSL (2 - init-systemd(redhat)) ERROR: UtilCreateProcessAndWait:707: /bin/mount>
Dec 16 08:28:46 PBD-IT-WL-rOMw1 unknown: WSL (2 - init-systemd(redhat)) ERROR: ConfigMountFsTab:2172: Processing /etc/f>

plus the well know message on login:

wsl: Processing /etc/fstab with mount -a failed.

and eventually I have that drive and use it!

This is the same with 6.x. Some version doesn't print it, but journalctl has it for any WSL above 2.4

Diagnostic Logs

No response

[github-actions]

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If this a feature request, please reply with '/feature'. If this is a question, reply with '/question'.
Otherwise, please attach logs by following the instructions below, your issue will not be reviewed unless they are added. These logs will help us understand what is going on in your machine.

How to collect WSL logs

Download and execute collect-wsl-logs.ps1 in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-wsl-logs.ps1

The script will output the path of the log file once done.

If this is a networking issue, please use collect-networking-logs.ps1, following the instructions in Collect WSL logs for networking issues

Once completed please upload the output files to this GitHub issue.

See Collect WSL logs (recommended method).

If you choose to email these logs instead of attaching them to the bug, please send them to wsl-gh-logs@microsoft.com with the GitHub issue number in the subject, and include a link to your GitHub issue comment in the message body, and reply with '/emailed-logs'.

[github-actions]

Logs are required for review from WSL team

If this a feature request, please reply with '/feature'. If this is a question, reply with '/question'.
Otherwise, please attach logs by following the instructions below, your issue will not be reviewed unless they are added. These logs will help us understand what is going on in your machine.

How to collect WSL logs

Download and execute collect-wsl-logs.ps1 in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-wsl-logs.ps1

The script will output the path of the log file once done.

If this is a networking issue, please use collect-networking-logs.ps1, following the instructions in Collect WSL logs for networking issues

Once completed please upload the output files to this GitHub issue.

See Collect WSL logs (recommended method).

If you choose to email these logs instead of attaching them to the bug, please send them to wsl-gh-logs@microsoft.com with the GitHub issue number in the subject, and include a link to your GitHub issue comment in the message body, and reply with '/emailed-logs'.

[tamasbencze]

WslLogs-2025-12-16_08-58-10.zip

[github-actions]

Diagnostic information

.wslconfig found
Detected appx version: 2.5.10.0

[tamasbencze]

I added the same fstab in Ubuntu for the same external vhdx, and there I also get the error message, just like in RedHat.
journalctl has about the same line here too:

Dec 16 16:26:19 PBD-IT-WL-rOMw1 systemd-journald[44]: Collecting audit messages is disabled.
Dec 16 16:26:19 PBD-IT-WL-rOMw1 systemd-journald[44]: Received client request to flush runtime journal.
Dec 16 16:26:19 PBD-IT-WL-rOMw1 systemd-journald[44]: File /var/log/journal/b0517f00eb24404bbedfaaa413d72fef/system.jou>
Dec 16 16:26:19 PBD-IT-WL-rOMw1 systemd-journald[44]: File /var/log/journal/b0517f00eb24404bbedfaaa413d72fef/user-1000.>
Dec 16 16:26:19 PBD-IT-WL-rOMw1 Exception:
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown: Operation canceled @p9io.cpp:258 (AcceptAsync)
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown:
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: EXT4-fs (sde): mounted filesystem with ordered data mode. Opts: discard,errors=>
Dec 16 16:26:19 PBD-IT-WL-rOMw1 mount:
Dec 16 16:26:19 PBD-IT-WL-rOMw1 /mnt/wsl/wsldata: mount point does not exist.
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown:
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown: dmesg(1) may have more information after failed mount system call.
Dec 16 16:26:19 PBD-IT-WL-rOMw1 mount:
Dec 16 16:26:19 PBD-IT-WL-rOMw1 /home/developer: special device /mnt/wsl/wsldata/home/developer does not exist.
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown:
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown: dmesg(1) may have more information after failed mount system call.
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown: WSL (2 - init-systemd(Ubuntu)) ERROR: UtilCreateProcessAndWait:688: /bin/mount>
Dec 16 16:26:19 PBD-IT-WL-rOMw1 unknown: WSL (2 - init-systemd(Ubuntu)) ERROR: ConfigMountFsTab:2594: Processing fstab >
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_is_feature_enabled: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -2
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22
Dec 16 16:26:19 PBD-IT-WL-rOMw1 kernel: misc dxg: dxgk: dxgkio_query_adapter_info: Ioctl failed: -22

Again, the drive is available and $HOME is mounted at the end.

[OneBlue]

@tamasbencze: What you're seeing is probably an ordering issue. Based on whether the distro starts with or without the disk mounted, the fstab error might show up.

One easy workaround would be to use a symlink instead of a bind mount. It still wouldn't work if the disk wasn't mounted, but at least it will start working automatically as soon as the disk is mounted.

[tamasbencze]

Do I interpret the situation correctly? The windows mount command itself starts wsl (default distro) to some extent and the mount is not there yet and it complains? And by the time I get in my distro it has the mount in place?
No, this is not the right explanation because if do this:

• wsl --shutdown
• wsl --set-default Ubuntu (this one is without fstab)
• wsl mount vhdx...
• wsl -d Ubuntu -> no fstab complaints
• wsl -d redhat -> still complains
  It still complains while the mounted whdx is already there, under /mnt/wsl since Ubuntu start.

So I don't understand the mechanics. In 1st step with Ubunu I have the mount available, what is wrong with the fstab in the 2nd distro?

[tamasbencze]

I tested many variations again, and I think I have this conclusion. Both the fstab problem that I and others reported and the systemd user session failure that also reported by others are the same or at least related.
I found now WSL build of RedHat (cloud image?). Earlier I used UBI images. The WSL image is better, it doesn different thing and differently and journalctl is just clean and out-of-the-box it works like the default Ubuntu. It has user session, and with the the latest 2.6 WSL too.
Until.. Until I try to mount my home drive.
Now the vhdx HOME here also has the above messages in journalctl, saying my wsldata mount is not found. And it is there and available by the time type anthing. Even the home mount in fstab works.
And together with the fstab error I get the user session error on the terminal.
RHEL10.1+WSL 2.6.3
wsl: Processing /etc/fstab with mount -a failed.
wsl: Failed to start the systemd user session for 'developer'. See journalctl for more details.

And before it had all the bus and session and podman worked without complaints.
The problem around the mount breaks systemd to some extent, like the /run/user/1000.
My thought is if external wsldata mount problem would go away, the official redhat wsl image would work perfectly with recent WSL.

With the fresh wsl redhat image, if you adduser, that user has the user session and the bus. Once I mount the vhdx, I see that errors in journalctl and the systemd session breaks with the bus and the rest.

So is there clean and problem-free way of mounting vhdx and use it as a HOME drive?

[tamasbencze]

One more note.
The errors for wsldata mount in journalctl is there in Ubuntu too. Only it doesn't break Ubuntu's user session. There the bus is visible and systemlctl --user status runs.
And wsldata is available regardless of the errors on boot.
Just like RH, but there the mount problem has effect on the user session and dbus.