KDE Plasma 6.7 Out of memory with 3D enabled

[gbohn]

I have a Fedora 43 Guest running KDE Plasma on a Windows 11 (25H2) Host. It has (had) Guest 3D acceleration turned on and was working o.k. I give it 20 GB of memory.

Today I applied updates and now it crashes the Guest with a severe Guest memory leak of some kind, but only when Guest 3D acceleration is enabled. Without 3D acceleration enabled it seems to run o.k. (at least for the few minutes I tried it).

Today's updates included updates to KDE to bring it up from version 6.6 to version 6.7, for what it's worth.

At any rate, if 3D acceleration is enabled, the OOM killer kills off something within a minute or two of logging in, and I am back to the login page. What the OOM killer kills off seems to vary.

The Guest System monitor shows a steady severe increase in overall memory usage, although the specific process list doesn't seem to point out any abnormal individual program as best as I could tell.

Anyone else seeing the same issue?

Oops- Forgot to mention that this is with Workstation 25H2u1. I also tried this on a different Windows 11 Host with a similar (but different) Fedora 43 Guest. It shows the same issue when Guest 3D is enabled.

[uvarvu]

Yes, I have the same problem.  I'm running KDE Neon, after opening a terminal and repeatedly type "free" to check my resource usage, I can see the memory usage slowly increasing.

[Dhairya Tomar]

gbohn Raised ticket internally, relevant team will look into the issue.

[gbohn]

Any word on if they have reproduced this and if there is a workaround (other than disabling 3D)?

[Maaz Mombasawala]

We have reproduced the issue and are working on a fix.

[Maaz Mombasawala]

Hi, we have reproduced the issue on our end and are working on a fix.

[richard612]

Interim workaround: downgrade kwin to 6.6.5.  Download .rpm packages from koji.  You'll need kwin, kwin-common, and kwin-libs.  In the download folder:

sudo dnf downgrade ./kwin*6.6.5*

[Technogeezer]

Sounds to me like a regression in either KDE Plasma or Mesa 3D in the guest. You might want to see if this has been reported to the KDE and/or Mesa developers as well. 

What kernel and Plasma version were installed? You might want to see if there are updated components for kernel/Plasma/Mesa for F43 - especially if the Plasma version is 6.7.0

------------------------------
Paul Rockwell (technogeezer)
vExpert 2026 (3x)
------------------------------

[gbohn]

> What kernel and Plasma version were installed?

I've been suppressing the update to Plasma with a modified /etc/dnf/dnf.conf file to exclude new KDE Plasma versions.

I just tried letting it update again, but I see the same issue after updating to the newest versions (that come with Fedora 43).

Using the same Mesa (25.3.6-3.fc43) and kernel (7.1.3-100.fc43) level, KDE Plasma 6.6.5-2.fc43 works o.k. with 3D enabled and KDE version 6.7.2-2.fc43 does not.

I'm not sure how to see if the KDE people are aware. But, this leak is so severe that it makes using the system impossible. 

So, I'm guessing that if this also affected non Vmware Workstation environments as well then they would likely have already noticed.

[richard612]

Guys, I spent half an hour on this yesterday.  It's kwin.  Nothing turned up on bugs.kde so I don't reckon they know (yet).  Can someone let them know?  I have my hands full this week.

[Nisar Ahmed]

Thanks for the clear breakdown - isolating it to Plasma 6.6.5 (working) vs 6.7.2 (broken) with identical Mesa/kernel strongly points to a Plasma/KWin regression, not Mesa or the kernel.

A few things worth checking:

1. Confirm renderer – run glxinfo | grep "OpenGL renderer" to verify it's using VMware's SVGA3D backend and not falling back to software rendering.
2. open-vm-tools version – make sure it's up to date; Plasma 6.7's new KWin scene graph has caused issues with older SVGA3D backends elsewhere too.
3. Check logs during the leak: journalctl -b -u kwin_wayland -f (or plasma-kwin_x11 on X11) for repeated buffer/texture allocation messages.
4. File on bugs.kde.org against kwin, tagged "virtual machine"/"VMware SVGA3D" - KDE devs likely aren't testing against VMware's 3D backend, so your exact repro (Mesa + kernel + Plasma versions) would help a lot.
5. Workaround: disable OpenGL compositing and force XRender (System Settings → Compositor) until it's fixed upstream.

Given the severity, this does look isolated to VM/SVGA3D environments rather than bare metal.

[gbohn]

So I opened a report (523098) at bugs.kde.org against kwin back on 7/15/26. I don't know if I got everything entered correctly or not.

I don't know how long it normally takes for a response of any sort, but nothing but the sound of crickets in response so far...

I recently tried KDE 6.7.3 without any improvement. I also tried updating KDE (from 6.6.5) to 6.7.3, but excluding kwin from being updated.

That seemed to boot without showing the memory leak. But I didn't run it for more than a few minutes so I don't know if anything would be messed up by updating everything but kwin.

[richard612]

I've fully patched my F44 VM tonight and the problem seems to be fixed.  kwin is 6.7.3-1.fc44.

[gbohn]

I just tried updating my Fedora 43 again, but the problem persists. (I think it may have been the same level I tried a couple of days ago).

Updated KDE was version 6.7.3-2.fc43.

So, either Fedora 43 is still problematic or your system is somehow a bit different.

Not sure if it's at all related, but the system I tried this on most recently is using an Nvidia 4070 Super graphics card on a Windows 11 Host with video driver 596.36.

(And of course Guest 3D acceleration enabled).

[Maaz Mombasawala]

The fix for this has been merged into upstream mesa and should be available in the next version, mesa 26.3.

Also note that this was a bug in our driver, the last kwin release simply triggered it.

[gbohn]

Thanks.

If I understand you correctly, it sounds like you're saying MESA 26.3 will circumvent an issue with the Workstation video driver.

Sadly for me (at least according to google),

*) Mesa 26.3 likely won't be released until November or December

and

*) Mesa 26.3 is not expected to ever come to Fedora 43.

Are you planning on ever releasing a fixed Workstation driver? (Assuming Mesa is not where the driver lives).

[Maaz Mombasawala]

I've backported the fix into mesa 26.1 so it should be included in the next release of mesa 26.1 and mesa 26.2 as well, so you should get it sooner.

Also, our svga driver is part of mesa, there is no separate workstation video driver.

[richard612]

Interesting.  So vmwgfx.ko ships with mesa and not open-vm-tools.

[Technogeezer]

Actually vmwgfx.so ships with the Linux kernel. There are other components for VMware 3D support that are part of Mesa.

------------------------------
Paul Rockwell (technogeezer)
vExpert 2026 (3x)
------------------------------

[Technogeezer]

Clarification to my prior statement. The vmwgfx.ko kernel driver ships as part of the Linux kernel. Mesa ships with a module vmwgfx_dri.so which appears to me to be Mesa's interface to the features provided by the vmwgfx kernel driver. My suspicion based on what @Maaz Mombasawala states is that the bug lies in the Mesa module.

I guess this a TL;DR way of saying that VMware video drivers for Linux are not part of open-vm-tools. 

------------------------------
Paul Rockwell (technogeezer)
vExpert 2026 (3x)
------------------------------