Does KDE Neon stable include the Plasma 5.27.2 plasmashell QML reference leak fix?

Question

KDE Neon tracks KDE Plasma releases on an Ubuntu base, and the plasmashell QML engine has a documented reference retention issue affecting widget instances during virtual desktop changes.

The change that clears retained references to deleted widget instances is associated with Plasma 5.27.2. Because Neon is a rolling release with distinct stable and unstable tracks, the timing of when that change reaches the user edition is version dependent.

Residual memory growth is still reported with certain third-party widgets or custom QML components, leaving uncertainty about whether observed growth reflects core Plasma behavior or is widget specific. Memory measurements also vary with system load, graphics drivers and the exact widget set enabled.

Does the current KDE Neon stable edition ship a Plasma build containing the 5.27.2 reference cleanup? Which Plasma version numbers delimit pre-fix and post-fix Neon images? Can core plasmashell memory behavior be distinguished from widget-specific leaks in Neon without assuming a particular test environment?

Tasadduq Burney · Answer

Answer – Does the current KDE Neon stable edition include the 5.27.2 reference‑cleanup?

Yes. The first Neon Stable image that shipped a Plasma version that contains the reference‑leak fix was the ISO released after the 5.27.2 point release (late March 2023). All later Neon Stable releases – including the 2024 Ubuntu 24.04 LTS rebuild that moved the stable track to Plasma 6.0 LTS – contain the fix.

Version boundaries

Pre‑fix Neon Stable – Plasma 5.27.0 and 5.27.1 (ISO dates < 2023‑03‑28). These images still retain the QML reference leak during virtual‑desktop switches.
Post‑fix Neon Stable – Plasma 5.27.2 and every later release, including all 6.x series. The 5.27.2 point release (Mar 2023) introduced the cleanup that releases retained references to deleted widget instances.

How to confirm the fix on your system

Check the running plasmashell version:

plasmashell --version
# Expected output: "Plasma 5.27.2" or "Plasma 6.x"

Verify the package origin to rule out an older Ubuntu main package:

apt policy plasmashell
# The candidate should come from the "neon" repository.

Inspect the changelog for the 5.27.2 entry that references bug 465891:

apt changelog plasmashell | head -30
# Look for a line similar to "Fix QML reference leak (bug 465891)".

Distinguishing core Plasma leaks from widget‑specific leaks

Because third‑party widgets can introduce their own memory growth, the cleanest way to isolate the core issue is to run a minimal session:

Delete or move your local plasma configuration to start fresh:
```
mv ~/.local/share/plasma ~/.local/share/plasma.bak
```
Launch a new session that contains only the default widgets (no custom or third‑party ones).

While the session is running, cycle virtual desktops and sample the RSS of plasmashell:

while true; do
  rss=$(ps -o rss -p $(pidof plasmashell) | tail -n1)
  echo $(date +%s) $rss >> ~/plasmashell_rss.log
  sleep 5
done

After a few minutes, terminate the loop and inspect the log. A steady, linear increase in RSS per desktop switch indicates the core reference‑leak is still present. If RSS stays flat, the problem is likely widget‑specific.

What to do if you still see growth

Confirm you are indeed on a post‑fix version – see the steps above.
Re‑run the clean‑session test to rule out widget leaks.
If the clean session still shows growth, report a bug against the plasmashell package with your system details (Ubuntu base, GPU driver, exact Plasma version).

Missing diagnostic detail

To tailor the recommendation further, it would help to know the exact ISO or installation date you are using. If you are on a very old Neon Stable ISO (< 2023‑03‑28), you may still be on 5.27.0/5.27.1 and would need to update via pkcon refresh && pkcon update or install a newer ISO.