https://bugs.kde.org/show_bug.cgi?id=507799

--- Comment #1 from Graham G <[email protected]> ---
Sent my logs and steps over to ChatGPT's o3, and had ran a few other diagnostic
things it suggested. Here's that output, incase it's helpful.

Title: plasmashell crash during SceneWallpaper teardown; render thread wedged
in NVIDIA driver (vkQueueSubmit via GLX), dual-GPU X11

Summary
Plasma (X11, kwin_x11) occasionally crashes while tearing down a wallpaper
scene (wallpaper-engine-kde-plugin). The render/looper thread blocks inside the
NVIDIA userspace driver during vkQueueSubmit, while the main thread attempts to
stop/join it. Looks like a GLX↔Vulkan interop deadlock at shutdown, possibly
exacerbated by a headless second NVIDIA GPU.

Environment

    Distro: Pop!_OS 22.04 (Jammy base)

    Plasma session: X11 (kwin_x11)

    GPUs: RTX 3080 (display) + RTX 3060 (headless)

    NVIDIA: 570.172.08 (kernel + userspace match)

        nvidia-smi → 570.172.08, CUDA 12.8

        /proc/driver/nvidia/version → 570.172.08

    OpenGL: 4.6 (NVIDIA 570.172.08)

    Vulkan: 1.3.280, NVIDIA ICD present

    Plugin involved: wallpaper-engine-kde-plugin (scene backend; Vulkan path)

Frequency
Very rare; occurs during teardown/shutdown of wallpaper scene / plasmashell.

What happened

    Thread 7 (render): blocks in libnvidia-glcore.so.570.172.08 via
libGLX_nvidia.so.0 during vvk::Queue::Submit(...) →
VulkanRender::Impl::drawFrameOffscreen() → drawFrame(Scene&).

    Thread 1 (main): wallpaper::looper::Looper::stop() → std::thread::join()
while QML/scene objects are being destroyed (SceneWallpaper, MainHandler,
SceneObject), then KCrash.

    Secondary 3060 is headless; kernel dmesg shows nvidia ... Cannot find any
crtc or sizes for 02:00.0.

Expected
Plasmashell / wallpaper teardown completes cleanly; no crash or hang even if a
render thread is active.

Actual
Render thread never returns from driver submit; plasmashell tears down
QML/scene graph while blocked thread is being joined → crash.

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