Memory leak on lxpanel

[rin67630]

Describe the bug
The panel of the current version (and previous ones) of Raspberry Pi suffers from a memory leak.
The system runs further but becomes inoperable remotely.

To reproduce
Just let Raspbery Pi run for a long time, after a few months (almost) no menu function will be callable.
The system runs further but becomes inoperable, can't even call Terminal

Expected behaviour
Call e.g terminal

Actual behaviour
Got out of memory message "Failed to fork (Cannot allocate memory)"
cf also https://www.raspberrypi.org/forums/viewtopic.php?t=267015

System
Cannot load any new task on that system ( working else normally, for what is loaded)
especiallly not Terminal to call reports.

• Which model of Raspberry Pi? e.g. Pi3B+, PiZeroW
  All models

• Which OS and version (cat /etc/rpi-issue)?
  e.g.
  Distributor ID: Raspbian
  Description: Raspbian GNU/Linux 9.13 (stretch)
  Release: 9.13
  Codename: stretch
  but also the current version with updates upgrades from 6 weeks ago.

• Which firmware version (vcgencmd version)?
  e.g.
  version 0e6daa5106dd4164474616408e0dc24f997ffcf3 (clean) (release) (start)

• Which kernel version (uname -a)?
  e.g 4.19.66-v7+ crash on 4.1.15 #1253

Logs
cannot call terminal, hence no log

Additional context
N.B. All systems are remote, running VNC with team connection.

I did find a workaround: depress the bluetooth button on the panel.

This reloads the panel and everything gets cleared!
So could this help to find the culprit?

[lionello]

I'm running into this too. @rin67630 what do you mean with "depress the bluetooth button"?

[JanDiederich]

I get this with a self-written software after a few hours. After 10 hours the 4 GiB of my Raspberry Pi 4 are nearly full!
I suspected at first my own software, but it uses barely any memory, and if it has a leak it's tiny. lxpanel memory usage explodes. Restarting lxpanel seems to fix everything.

This should fix it longer, by automating it:
Open Terminal
Enter crontab -e.
Add this entry, to restart the lxpanel every full hour:

0 * * * * /bin/bash -l -c "export DISPLAY=:0 && lxpanelctl restart"

The DISPLAY=:0 should be equal to the DISPLAY setting in your users env output.

As addon in the panel I have only the listing of the open programs.

[rin67630]

I'm running into this too. @rin67630 what do you mean with "depress the bluetooth button"?
Sorry for the late answer.
In the panel there is a Bluetooth field. If you click on it it fixes temporarily the memory leak.

[galmok]

Restarting lxpanel is the only solution right now, but due to security, it cannot be done with "export DISPLAY=:0 && lxpanelctl restart":

root@raspberrypi:~# DISPLAY=:0 lxpanelctl restart
Invalid MIT-MAGIC-COOKIE-1 keyCant connect to display: :0

We need a solution to this problem. 1-2 weeks of of idle time and lxpanel consumes all memory and crashes the OS.

[galmok]

I upgraded my RPi OS to the latest (there is a guide somewhere) and now the lxpanel is ok (no more huge memory consumption).

[Master-Code-Programmer]

I upgraded my RPi OS to the latest (there is a guide somewhere) and now the lxpanel is ok (no more huge memory consumption).

Can confirm. I completely reinstalled Raspberry PI OS in its latest version, and the bug is gone.

[rin67630]

The last version?
Do you mean Bookworm with Wayland?
That does not work on the weakest Raspberries, those freqently used remotely.
I don't consider it solved.

[galmok]

Just checked the version I am running and it says "12 (bookworm)" in /etc/os-release.

[rin67630]

Yes, I meant Bookworm with Wayland, which has a completely different windowing system.
So the bug remains for the weakest systems (with the least memory), those running headless and X-11 remote, supported by VNC.
Please reopen that issue.
P.S. the memory leak is very plausibly in the bluetooth module of LXpanel.
With Bluetooth permanently disabled, there is no memory leak.
Using Bluetooth only from time to time is OK as well.
Just don't leave it on for days...