Application: kwin_x11 (5.21.5)

Qt Version: 5.15.2
Frameworks Version: 5.86.0
Operating System: Linux 5.14.0-2-amd64 x86_64
Windowing System: X11
Distribution: Debian GNU/Linux bookworm/sid
DrKonqi: 5.23.0 [KCrashBackend]

-- Information about the crash:
KWin can no longer start after upgrading my Debian system about a week ago; I've installed debug packages to get a good stacktrace, and from looking at that and my apt history I suspect the issue was caused by upgrading libkdecorations2-5v5:amd64 from 4:5.21.5-2 to 4:5.23.0-2. (I can also send the rest of the apt history from the last day it was working if it will help)

I can still run other window managers, and I am currently using Awesome as a stop-gap to get my system working again.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault

[KCrash Handler]
#4  0x00007fe80a401510 in KDecoration2::DecorationSettings::font (this=this@entry=0x55623c3722e0) at /usr/include/c++/11/bits/unique_ptr.h:173
#5  0x00007fe80a401737 in operator() (__closure=<synthetic pointer>) at ./src/decorationsettings.cpp:19
#6  KDecoration2::DecorationSettings::DecorationSettings (this=0x55623c3722e0, bridge=0x55623c339430, parent=<optimized out>) at ./src/decorationsettings.cpp:34
#7  0x00007fe80c4a2add in KWin::Decoration::DecorationBridge::init() () from /lib/x86_64-linux-gnu/libkwin.so.5
#8  0x00007fe80c5a75a7 in KWin::Workspace::Workspace() () from /lib/x86_64-linux-gnu/libkwin.so.5
#9  0x00007fe80c500990 in KWin::Application::createWorkspace() () from /lib/x86_64-linux-gnu/libkwin.so.5
#10 0x000055623a2a841e in KWin::ApplicationX11::continueStartupWithScreens (this=0x7ffec16b3740) at ./main_x11.cpp:272
#11 0x00007fe80b0a5977 in QtPrivate::QSlotObjectBase::call (a=0x7ffec16b2fd0, r=0x7ffec16b3740, this=0x55623c3439b0) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#12 doActivate<false> (sender=0x55623c278500, signal_index=3, argv=0x7ffec16b2fd0) at kernel/qobject.cpp:3886
#13 0x00007fe7f8206d73 in KWin::X11StandalonePlatform::doUpdateOutputs<KWin::Xcb::RandR::ScreenResources> (this=0x7ffec16b30a8) at ./plugins/platforms/x11/standalone/x11_platform.cpp:603
#14 0x00007fe7f8200779 in KWin::X11StandalonePlatform::initOutputs (this=0x55623c278500) at ./plugins/platforms/x11/standalone/x11_platform.cpp:473
#15 0x00007fe7f82007d1 in KWin::X11StandalonePlatform::init (this=0x55623c278500) at ./plugins/platforms/x11/standalone/x11_platform.cpp:143
#16 0x000055623a2a7ddd in operator() (__closure=0x55623c1b7580) at ./main_x11.cpp:259
#17 QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, KWin::ApplicationX11::performStartup()::<lambda()> >::call (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:146
#18 QtPrivate::Functor<KWin::ApplicationX11::performStartup()::<lambda()>, 0>::call<QtPrivate::List<>, void> (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:256
#19 QtPrivate::QFunctorSlotObject<KWin::ApplicationX11::performStartup()::<lambda()>, 0, QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase *, QObject *, void **, bool *) (which=<optimized out>, this_=0x55623c1b7570, r=<optimized out>, a=<optimized out>, ret=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:443
#20 0x00007fe80b0a5977 in QtPrivate::QSlotObjectBase::call (a=0x7ffec16b32f0, r=0x55623c1b5aa0, this=0x55623c1b7570) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#21 doActivate<false> (sender=0x55623c1b5aa0, signal_index=4, argv=0x7ffec16b32f0, argv@entry=0x0) at kernel/qobject.cpp:3886
#22 0x00007fe80b09ecc0 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7fe80c32e680 <KSelectionOwner::staticMetaObject>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x0) at kernel/qobject.cpp:3946
#23 0x00007fe80c2f73d3 in KSelectionOwner::claimedOwnership (this=<optimized out>) at ./obj-x86_64-linux-gnu/src/KF5WindowSystem_autogen/HBARIMPYTU/moc_kselectionowner.cpp:160
#24 0x00007fe80c30a223 in KSelectionOwner::Private::claimSucceeded (this=0x55623c1a9330) at ./src/platforms/xcb/kselectionowner.cpp:187
#25 0x00007fe80b09b6af in QObject::event (this=0x55623c1b5aa0, e=0x7ffec16b34c0) at kernel/qobject.cpp:1336
#26 0x00007fe80bc1374f in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x55623c1b5aa0, e=0x7ffec16b34c0) at kernel/qapplication.cpp:3632
#27 0x00007fe80b06ee9a in QCoreApplication::notifyInternal2 (receiver=0x55623c1b5aa0, event=0x7ffec16b34c0) at kernel/qcoreapplication.cpp:1063
#28 0x00007fe80b0c5e53 in QTimerInfoList::activateTimers (this=this@entry=0x7fe7fc000df8) at kernel/qtimerinfo_unix.cpp:643
#29 0x00007fe80b0c359c in QEventDispatcherUNIXPrivate::activateTimers (this=this@entry=0x7fe7fc000d70) at kernel/qeventdispatcher_unix.cpp:249
#30 0x00007fe80b0c42e7 in QEventDispatcherUNIX::processEvents (this=<optimized out>, flags=...) at kernel/qeventdispatcher_unix.cpp:516
#31 0x00007fe80458d89e in ?? () from /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#32 0x00007fe80b06d8db in QEventLoop::exec (this=this@entry=0x7ffec16b3660, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:69
#33 0x00007fe80b075b10 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#34 0x000055623a2a6fa9 in main (argc=<optimized out>, argv=0x7ffec16b38e8) at ./main_x11.cpp:491
[Inferior 1 (process 68967) detached]

Possible duplicates by query: bug 442809, bug 442794, bug 442711, bug 440464, bug 440116.

Reported using DrKonqi