[Bug]: SEGV in plasmashell with darkly trying to spawn threads in disallowed places

[UnicodeMan]

Describe the bug

It's likely due to some threading issues as per the log at the bottom.
plasmashell crashed, but also I have issues with vscode - resizing window would oddly be responsive, but it would not register mouse or keyboard events/clicks/hovers, but it may be unrelated.
Some random vscode window would be affected, not all.
It would make some sense if event loop locks up.
It may be some misbehaving app thats causing issues across apps.

OS is NixOS (nixos-unstable branch). Linux kernel 6.18.2.
CPU: Intel i5-12600K
GPU: AMD Radeon RX 6800 XT
Graphics platform: Wayland

Darkly theme version

Darkly 0.5.25

Plasma version

Plasma 6.5.4

Qt version

Qt 6.10.1

Add screenshot

it thinks this is the default colour scheme (but it looks like breeze classic)

Which distribution are you using?

NixOS (nixos-unstable branch)

Which color-scheme are you using?

Technically system settings say gently-color-light-blue but its breeze classic. Also it things gently-... is the default.

Wayland / X11 session in use?

Wayland

Is fractional scaling being used?

y

Add any other context about the bug here

I copy pasted some relevant logs, but I'm happy to provide more, including GDB'ed coredump logging.

logs.md

[UnicodeMan]

It may be that my Plasma config files in /home have reached a certain age and configuration cycles that they need to be wiped.
Honestly I find that if you start customizing Plasma more than just a bit, things start to break. Been that way since Plasma 4. But maybe thats not the issue here.

[Bali10050]

Resizing vscode with fractional scaling can kill your pc regardless of what you're using, it's ai filled electron slop straight from microsoft.

Other than that, darkly has more than 50 options just by itself and it's just one of the many customization options inside kde, so narrowing down the problem without a clear config is not something I recommend doing.

If the plasmashell keeps crashing please test a clear config with the latest version of darkly, and if that also has the problem give me detailed info on how I can reproduce the issue. If only vscode has a problem please close the issue, it's an electron app with client side decoration, it shouldn't be using darkly anywhere

[DeltaCopy]

I cannot replicate this on Archlinux.
Resizing VSCode works as intended, no Plasmashell crashes even with fractional scaling set to > 150%

[UnicodeMan]

The vscode complaint may be irrevent, as wayland is finnicky with cursor grab and i managed to escape cursor grab by either finding out which window caused it and deselecting popup, or replugging usb mouse.

There was an issue as per logs that darkly tried to create threads where it was not supposed to, until it finally crashed. Thats the part of log thats interesting.

The question is, what would cause such behaviour - it may be some recovery mechanism that activates on graphics stack freeze, or it may be some unsafe memory access that ruins subsequent program execution.
Id say it would be good to check if null ptr access happens at some point, but its hard to know with no clear way to reproduce it.

Honestly I had GPU disappear from the pcie bus one time, and that may be related.
If that is the case, then the question is if darkly somehow bugs out amdgpu driver, or the driver is faulty and darkly somehow triggers a bug.
To put it in chronological terms:

1. Graphics freeze then black screen (logs showed gpu was no longer detected, but system ran fine otherwise
2. Reseated GPU in case of faulty connection to motherboard, rebooted
3. plasmashell crash happened a while later as per this issue.
4. since i switched to breeze, everything runs smoothly

I did not enable any XMP profiles because 12th gen intel has weak memory controller, so left at 4800MT and it runs stable. So not likely memory corruption of hardware.

Id be more in line to keep this issue open for a while in case someone with amd gpu also has weird issues with darkly, or stress testing it with many windows and various interactions to see if that affects darkly stability.

[UnicodeMan]

QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9ce480), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9ce480), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9ce640), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9ce640), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is Darkly::WidgetStateEngine(0x55d41b9d18f0), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
                                           (Parent is KNotificationManager(0x7fdb8c515d10), parent's thread is QThread(0x55d41b655a40), current thread is QThread(0x55d41d6255b0)
saus. 05 18:12:40 MSIPC plasmashell[2953]: QObject: Cannot create children for a parent that is in a different thread.
                                           (Parent is QTextDocument(0x7fdaec29eec0), parent's thread is QThread(0x55d41d6255b0), current thread is QThread(0x55d41b655a40)
saus. 05 18:12:40 MSIPC plasmashell[2953]: KCrash: Application '.plasmashell-wrapped' crashing... crashRecursionCounter = 2
saus. 05 18:12:40 MSIPC systemd-coredump[1839357]: Process 2953 (.plasmashell-wr) of user 1000 terminated abnormally with signal 11/SEGV, processing...
saus. 05 18:12:40 MSIPC systemd[1]: Started Process Core Dump (PID 1839357/UID 0).
saus. 05 18:12:40 MSIPC systemd[1]: Started Pass systemd-coredump journal entries to relevant user for potential DrKonqi handling.

A snippet of the logs shows spamming of threads.