Bug 515412

Summary: plasmashell sometimes crashes when switching windows using alt tab from full screen (crash in QConcatenateTablesProxyModel via TaskGroupingProxyModel)
Product: [Plasma] plasmashell Reporter: ono <ono1100>
Component: Task Manager and Icons-Only Task Manager widgetsAssignee: Plasma Bugs List <plasma-bugs-null>
Status: NEEDSINFO WAITINGFORINFO    
Severity: crash CC: akselmo, notmart, qydwhotmail
Priority: NOR    
Version First Reported In: 6.5.5   
Target Milestone: 1.0   
Platform: CachyOS   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Backtrace (core dump)

Description ono 2026-02-02 02:56:19 UTC 
Created attachment 189155 [details]
Backtrace (core dump)

SUMMARY
Sometimes when I alt tab to some other app from a fullscreen game, it causes plasma to crash. I think its due to the notifications that got suppressed during the full screen game (due to DND) and now tries to show a notification that X notifications were missed. Also it seems some app is asking for attention (yellow) in the task manager too when this crash happens. So could be a race condition. 

It doesn't happen often (2 times in last month) but I thought I would report it anyways. The issue can be closed if its deemed a one off condition or not clear.

STEPS TO REPRODUCE
(I cannot reproduce it consistently)
0. (Icon Only) Task Manager is configured to Group tasks ("By Program Name")
1. Start some game in full screen (and wait for some time).
2. Wait for events that trigger notifications or cause an app to "Demand Attention" (orange/bouncing icon in taskbar).
3. Alt tab out of the game to another running app (like the terminal). 

OBSERVED RESULT
plasmashell crashes

EXPECTED RESULT
plasmashell doesn't crash

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: CachyOS (Arch)
KDE Plasma Version: 6.5.5
KDE Frameworks Version: 6.22.0
Qt Version: 6.10.2

ADDITIONAL INFORMATION
backtrace: https://privatebin.at/?eda0eff0679a3181#8NWppx8BxfSaygmbk8ksL8m4PeCzpaFiZXxoTVsCJVLm (also added as an attachment)

(maybe related bugs? : 496800, 482446)
Comment 1 Marco Martin 2026-02-02 09:41:22 UTC 
Pasting inline:
#0  0x00007f3d08c70e66 in QConcatenateTablesProxyModel::index(int, int, QModelIndex const&) const () at /usr/lib/libQt6Core.so.6
    #1  0x00007f3d08c8bd46 in QSortFilterProxyModel::data(QModelIndex const&, int) const () at /usr/lib/libQt6Core.so.6
    #2  0x00007f3cebf4c7f4 in QModelIndex::data () at /usr/include/qt6/QtCore/qabstractitemmodel.h:519
    #3  TaskManager::TaskGroupingProxyModel::data ()
        at /usr/src/debug/plasma-workspace/plasma-workspace-6.5.5/libtaskmanager/taskgroupingproxymodel.cpp:748
    #4  0x00007f3d08c8bc08 in QSortFilterProxyModel::data(QModelIndex const&, int) const () at /usr/lib/libQt6Core.so.6
    #5  0x00007f3cebf55965 in TaskManager::TasksModel::data ()
        at /usr/src/debug/plasma-workspace/plasma-workspace-6.5.5/libtaskmanager/tasksmodel.cpp:1078
    #6  0x00007f3d08c32a05 in ??? () at /usr/lib/libQt6Core.so.6
    #7  0x00007f3d08c33e13 in QAbstractItemModel::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib/libQt6Core.so.6
    #8  0x00007f3d08c6cae9 in QAbstractProxyModel::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib/libQt6Core.so.6
    #9  0x00007f3d08c97019 in QSortFilterProxyModel::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib/libQt6Core.so.6
    #10 0x00007f3cebf61bfa in TaskManager::TasksModel::qt_metacall ()
        at /usr/src/debug/plasma-workspace/build/libtaskmanager/taskmanager_autogen/include/moc_tasksmodel.cpp:672
    #11 0x00007f3d09f5bc54 in ??? () at /usr/lib/libQt6Qml.so.6
    #12 0x00007f3d09dfc93b in QV4::QObjectMethod::callPrecise(QQmlObjectOrGadget const&, QQmlPropertyData const&, QV4::ExecutionEngine*, QV4::CallData*, QMetaObject::Call) () at /usr/lib/libQt6Qml.so.6
    #13 0x00007f3d09dff3e3 in QV4::QObjectMethod::callInternal(QV4::Value const*, QV4::Value const*, int) const () at /usr/lib/libQt6Qml.so.6
    #14 0x00007f3d09e20e94 in QV4::Runtime::CallPropertyLookup::call(QV4::ExecutionEngine*, QV4::Value const&, unsigned int, QV4::Value*, int) ()
        at /usr/lib/libQt6Qml.so.6
    #15 0x00007f3ccc73b9fe in ??? ()
    #16 0x00007ffcfe47aa70 in ??? ()
    #17 0x000055f7a1a84960 in ??? ()
    #18 0x000055f7a2d0d080 in ??? ()
    #19 0x0000000000000000 in ??? ()
    (gdb) bt full
    #0  0x00007f3d08c70e66 in QConcatenateTablesProxyModel::index(int, int, QModelIndex const&) const () at /usr/lib/libQt6Core.so.6
    #1  0x00007f3d08c8bd46 in QSortFilterProxyModel::data(QModelIndex const&, int) const () at /usr/lib/libQt6Core.so.6
    #2  0x00007f3cebf4c7f4 in QModelIndex::data () at /usr/include/qt6/QtCore/qabstractitemmodel.h:519
    #3  TaskManager::TaskGroupingProxyModel::data ()
        at /usr/src/debug/plasma-workspace/plasma-workspace-6.5.5/libtaskmanager/taskgroupingproxymodel.cpp:748
    #4  0x00007f3d08c8bc08 in QSortFilterProxyModel::data(QModelIndex const&, int) const () at /usr/lib/libQt6Core.so.6
    #5  0x00007f3cebf55965 in TaskManager::TasksModel::data ()
        at /usr/src/debug/plasma-workspace/plasma-workspace-6.5.5/libtaskmanager/tasksmodel.cpp:1078
    #6  0x00007f3d08c32a05 in ??? () at /usr/lib/libQt6Core.so.6
    #7  0x00007f3d08c33e13 in QAbstractItemModel::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib/libQt6Core.so.6
    #8  0x00007f3d08c6cae9 in QAbstractProxyModel::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib/libQt6Core.so.6
    #9  0x00007f3d08c97019 in QSortFilterProxyModel::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib/libQt6Core.so.6
    #10 0x00007f3cebf61bfa in TaskManager::TasksModel::qt_metacall ()
        at /usr/src/debug/plasma-workspace/build/libtaskmanager/taskmanager_autogen/include/moc_tasksmodel.cpp:672
    #11 0x00007f3d09f5bc54 in ??? () at /usr/lib/libQt6Qml.so.6
    #12 0x00007f3d09dfc93b in QV4::QObjectMethod::callPrecise(QQmlObjectOrGadget const&, QQmlPropertyData const&, QV4::ExecutionEngine*, QV4::CallData*, QMetaObject::Call) () at /usr/lib/libQt6Qml.so.6
    #13 0x00007f3d09dff3e3 in QV4::QObjectMethod::callInternal(QV4::Value const*, QV4::Value const*, int) const () at /usr/lib/libQt6Qml.so.6
    #14 0x00007f3d09e20e94 in QV4::Runtime::CallPropertyLookup::call(QV4::ExecutionEngine*, QV4::Value const&, unsigned int, QV4::Value*, int) ()
        at /usr/lib/libQt6Qml.so.6
    #15 0x00007f3ccc73b9fe in ??? ()
    #16 0x00007ffcfe47aa70 in ??? ()
    #17 0x000055f7a1a84960 in ??? ()
    #18 0x000055f7a2d0d080 in ??? ()
    #19 0x0000000000000000 in ??? ()
Comment 2 Akseli Lahtinen 2026-02-02 13:04:47 UTC 
I'm unable to reproduce this with konsole bells at least. Can you share what application is the one usually creating these notifications?

Operating System: KDE Linux 2026-02-01
KDE Plasma Version: 6.6.80
KDE Frameworks Version: 6.23.0
Qt Version: 6.10.2
Kernel Version: 6.18.7-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 3600 6-Core Processor
Memory: 16 GiB of RAM (15.5 GiB usable)
Graphics Processor: AMD Radeon RX 6600