#985994 kwin-x11: crashes randomly on ALT-TAB for switching between windows

Package:
kwin-x11
Source:
kwin
Description:
KDE window manager, X11 version
Submitter:
Russell Coker
Date:
2022-04-29 12:48:03 UTC
Severity:
normal
#985994#5
Date:
2021-03-27 15:54:36 UTC
From:
To:
kwin_x11 will crash if I repeatedly use ALT-TAB to switch between windows.
Once every 5 to 10 window switches it will crash.

# coredumpctl info
           PID: 120123 (kwin_x11)
           UID: 1000 (etbe)
           GID: 1000 (etbe)
        Signal: 11 (SEGV)
     Timestamp: Sun 2021-03-28 02:50:46 AEDT (46s ago)
  Command Line: /usr/bin/kwin_x11 --crashes 1
    Executable: /usr/bin/kwin_x11
 Control Group: /user.slice/user-1000.slice/session-4.scope
          Unit: session-4.scope
         Slice: user-1000.slice
       Session: 4
     Owner UID: 1000 (etbe)
       Boot ID: ea470da9187243d6b412d447fccb3e3d
    Machine ID: 1677a0a8ceed4907a4efd7544ca73ae0
      Hostname: liv
       Storage: /var/lib/systemd/coredump/core.kwin_x11.1000.ea470da9187243d6b412d447fccb3e3d.12012>
       Message: Process 120123 (kwin_x11) of user 1000 dumped core.

                Stack trace of thread 120123:
                #0  0x00007f49c3823ce1 n/a (/lib/x86_64-linux-gnu/libc-2.31.so (deleted) + 0x3bce1)
#985994#10
Date:
2021-04-09 09:57:40 UTC
From:
To:
Hello Russell,
could you still see this issue?

Were there more lines following in the "Stack trace of thread 120123"?

And as libc-2.31 is shown as deleted, I assume this
happened while libc package got updated while the kwin-x11
process was still using the previous version.

Kind regards,
Bernhard
#985994#15
Date:
2021-04-09 10:04:54 UTC
From:
To:
Application: KWin (kwin_x11), signal: Segmentation fault

[KCrash Handler]
#4  0x00007f42259bee08 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#5  0x00007f4225acd3cc in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x0000001e00000009 in ?? ()
#7  0x000055623023d9d0 in ?? ()
#8  0x00007f421a2d0000 in ?? ()
#9  0x0000556230c214a0 in ?? ()
#10 0x00007f421a2d0000 in ?? ()
#11 0x0000556230c214a0 in ?? ()
#12 0x00007f4225bcccc0 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#13 0x0000556230c214a0 in ?? ()
#14 0x00000000000002c4 in ?? ()
#15 0x00007f421a2d0000 in ?? ()
#16 0x00007fff507a42d0 in ?? ()
#17 0x00007fff507a4238 in ?? ()
#18 0x00007fff507a4590 in ?? ()
#19 0xf927f64bde692500 in ?? ()
#20 0x0000000000000080 in ?? ()
#21 0x0000000000000001 in ?? ()
#22 0x00007fff507a4450 in ?? ()
#23 0x0000556230d27da0 in ?? ()
#24 0x0000556230274a30 in ?? ()
#25 0x00007f4225aba83c in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#26 0x00007f4225914460 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#27 0x00007f422591464c in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#28 0x00007f422595b4a6 in
QV4::ExecutableCompilationUnit::linkToEngine(QV4::ExecutionEngine*) () from /
usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#29 0x00007f422595e3a3 in
QV4::ExecutableCompilationUnit::instantiate(QV4::ExecutionEngine*) () from /
usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#30 0x00007f42259d11a9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#31 0x00007f4225a6caf2 in QQmlObjectCreator::create(int, QObject*,
QQmlInstantiationInterrupt*, int) () from /usr/lib/x86_64-linux-gnu/
libQt5Qml.so.5
#32 0x00007f4225a6bf4f in QQmlObjectCreator::createInstance(int, QObject*,
bool) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#33 0x00007f4225a6c8bf in QQmlObjectCreator::create(int, QObject*,
QQmlInstantiationInterrupt*, int) () from /usr/lib/x86_64-linux-gnu/
libQt5Qml.so.5
#34 0x00007f4225a6bf4f in QQmlObjectCreator::createInstance(int, QObject*,
bool) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#35 0x00007f4225a6e848 in
QQmlObjectCreator::setPropertyBinding(QQmlPropertyData const*,
QV4::CompiledData::Binding const*) () from /usr/lib/x86_64-linux-gnu/
libQt5Qml.so.5
#36 0x00007f4225a6ecf4 in QQmlObjectCreator::setupBindings(bool) () from /usr/
lib/x86_64-linux-gnu/libQt5Qml.so.5
#37 0x00007f4225a6ac8b in QQmlObjectCreator::populateInstance(int, QObject*,
QObject*, QQmlPropertyData const*) () from /usr/lib/x86_64-linux-gnu/
libQt5Qml.so.5
#38 0x00007f4225a6bc55 in QQmlObjectCreator::createInstance(int, QObject*,
bool) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#39 0x00007f4225a6e848 in
QQmlObjectCreator::setPropertyBinding(QQmlPropertyData const*,
QV4::CompiledData::Binding const*) () from /usr/lib/x86_64-linux-gnu/
libQt5Qml.so.5
#40 0x00007f4225a6ecf4 in QQmlObjectCreator::setupBindings(bool) () from /usr/
lib/x86_64-linux-gnu/libQt5Qml.so.5
#41 0x00007f4225a6ac8b in QQmlObjectCreator::populateInstance(int, QObject*,
QObject*, QQmlPropertyData const*) () from /usr/lib/x86_64-linux-gnu/
libQt5Qml.so.5
#42 0x00007f4225a6bc55 in QQmlObjectCreator::createInstance(int, QObject*,
bool) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#43 0x00007f4225a6c8bf in QQmlObjectCreator::create(int, QObject*,
QQmlInstantiationInterrupt*, int) () from /usr/lib/x86_64-linux-gnu/
libQt5Qml.so.5
#44 0x00007f42259fd89b in QQmlComponentPrivate::beginCreate(QQmlContextData*)
() from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#45 0x00007f42259fec7a in QQmlComponent::create(QQmlContext*) () from /usr/
lib/x86_64-linux-gnu/libQt5Qml.so.5
#46 0x00007f42288a3553 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#47 0x00007f42288a40e2 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#48 0x00007f42288a4339 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#49 0x00007f4227431580 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#50 0x00007f422743545a in QTimer::timeout(QTimer::QPrivateSignal) () from /
usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#51 0x00007f4227426ecf in QObject::event(QEvent*) () from /usr/lib/x86_64-
linux-gnu/libQt5Core.so.5
#52 0x00007f4227ebc15f in QApplicationPrivate::notify_helper(QObject*,
QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#53 0x00007f42273faf6a in QCoreApplication::notifyInternal2(QObject*, QEvent*)
() from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#54 0x00007f4227451883 in QTimerInfoList::activateTimers() () from /usr/lib/
x86_64-linux-gnu/libQt5Core.so.5
#55 0x00007f422744fd17 in
QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#56 0x00007f4220eb2b7e in ?? () from /usr/lib/x86_64-linux-gnu/
libQt5XcbQpa.so.5
#57 0x00007f42273f992b in
QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/
x86_64-linux-gnu/libQt5Core.so.5
#58 0x00007f4227401ba0 in QCoreApplication::exec() () from /usr/lib/x86_64-
linux-gnu/libQt5Core.so.5
#59 0x000055622e7adf59 in ?? ()
#60 0x00007f4226db4d0a in __libc_start_main (main=0x55622e7adb90, argc=1,
argv=0x7fff507a6158, init=<optimized out>, fini=<optimized out>,
rtld_fini=<optimized out>, stack_end=0x7fff507a6148) at ../csu/libc-start.c:
308
#61 0x000055622e7ae45a in _start ()
[Inferior 1 (process 1267) detached]

I can't remember about the previous one, but the one I pasted in to this
message has everything.

The crash I just did was from a system that was booted after the libc
installation.
#985994#20
Date:
2021-04-09 13:40:09 UTC
From:
To:
Hello Russel,
thanks for the fast answer, unfortunately the
backtrace is not yet enough expressive.

Maybe you could also install the following debug symbol packages?

libqt5qml5-dbgsym libqt5core5a-dbgsym libqt5widgets5-dbgsym libqt5gui5-dbgsym kwin-common-dbgsym kwin-x11-dbgsym

These are located in a separate debug symbol repository,
which has to be enabled first and is described here:
https://wiki.debian.org/HowToGetABacktrace#Installing_the_debugging_symbols

Kind regards,
Bernhard
#985994#25
Date:
2021-04-10 02:33:07 UTC
From:
To:
[KCrash Handler]
#4  0x00007f29e3bfbe08 in memcpy (__len=1, __src=<synthetic pointer>,
__dest=0x0) at /usr/include/x86_64-linux-gnu/bits/string_fortified.h:34
#5  JSC::AssemblerBuffer::putIntegralUnchecked<signed char>
(this=0x7f29e518c660 <_IO_stdfile_2_lock>, value=15 '\017') at ../3rdparty/
masm/assembler/AssemblerBuffer.h:105
#6  0x00007f29e3d0a3cc in JSC::AssemblerBuffer::putByteUnchecked (value=15
'\017', this=0x7f29e518c660 <_IO_stdfile_2_lock>) at ../3rdparty/masm/
assembler/AssemblerBuffer.h:109
#7  JSC::X86Assembler::X86InstructionFormatter::twoByteOp (offset=0, scale=0,
index=JSC::X86Registers::eax, base=JSC::X86Registers::edi, reg=1,
opcode=JSC::X86Assembler::OP2_MOVZX_GvEb, this=0x7f29e518c660
<_IO_stdfile_2_lock>) at ../3rdparty/masm/assembler/X86Assembler.h:2229
#8  JSC::X86Assembler::movzbl_mr (dst=JSC::X86Registers::ecx, scale=0,
index=JSC::X86Registers::eax, base=JSC::X86Registers::edi, offset=0,
this=0x7f29e518c660 <_IO_stdfile_2_lock>) at ../3rdparty/masm/assembler/
X86Assembler.h:1356
#9  JSC::MacroAssemblerX86Common::load8 (dest=JSC::X86Registers::ecx,
address=..., this=0x7f29e518c660 <_IO_stdfile_2_lock>) at ../3rdparty/masm/
assembler/MacroAssemblerX86Common.h:553
#10 JSC::Yarr::YarrGenerator<(JSC::Yarr::YarrJITCompileMode)0>::readCharacter
(this=0x7f29e518c660 <_IO_stdfile_2_lock>, negativeCharacterOffset=...,
resultReg=JSC::X86Registers::ecx, indexReg=<optimized out>) at ../3rdparty/
masm/yarr/YarrJIT.cpp:580
#11 0x0000001e00000009 in ?? ()
#12 0x00007f29d8023880 in ?? ()
#13 0x00007f29dc50d000 in ?? ()
#14 0x000056475539d5f0 in ?? ()
#15 0x00007f29dc50d000 in ?? ()
#16 0x000056475539d5f0 in ?? ()
#17 0x00007f29e3e09cc0 in vtable for
JSC::LinkBuffer<JSC::MacroAssembler<JSC::MacroAssemblerX86_64> > () from /usr/
lib/x86_64-linux-gnu/libQt5Qml.so.5
#18 0x000056475539d5f0 in ?? ()
#19 0x00000000000002c4 in ?? ()
#20 0x00007f29dc50d000 in ?? ()
#21 0x00007ffd5f081c90 in ?? ()
#22 0x00007ffd5f081bf8 in ?? ()
#23 0x00007ffd5f081f50 in ?? ()
#24 0xa59c5be213f4b700 in ?? ()
#25 0x0000000000000080 in ?? ()
#26 0x0000000000000001 in ?? ()
#27 0x00007ffd5f081e10 in ?? ()
#28 0x00005647553bd270 in ?? ()
#29 0x0000564754c84450 in ?? ()
#30 0x00007f29e3cf783c in JSC::Yarr::jitCompile (pattern=...,
charSize=(unknown: 0x5f081c90), charSize@entry=JSC::Yarr::Char16,
vm=0x7f29dc50d000, vm@entry=0x564754c84450, codeBlock=...,
mode=mode@entry=JSC::Yarr::IncludeSubpatterns) at ../3rdparty/masm/yarr/
YarrJIT.cpp:4021
#31 0x00007f29e3b51460 in QV4::Heap::RegExp::init (this=0x7f29bb601600,
engine=engine@entry=0x564754c84450, pattern=..., flags=1594367496,
flags@entry=1594367816) at jsruntime/qv4regexp.cpp:224
#32 0x00007f29e3b5164c in QV4::MemoryManager::alloc<QV4::RegExp,
QV4::ExecutionEngine*, QString, unsigned int> (this=<optimized out>) at
jsruntime/qv4value_p.h:101
#33 QV4::RegExp::create (engine=engine@entry=0x564754c84450, pattern=...,
flags=1594367816, flags@entry=1) at jsruntime/qv4regexp.cpp:199
#34 0x00007f29e3b984a6 in QV4::ExecutableCompilationUnit::linkToEngine
(this=this@entry=0x7f29b40c9bc0, engine=engine@entry=0x564754c84450) at
jsruntime/qv4executablecompilationunit.cpp:160
#35 0x00007f29e3b9b3a3 in QV4::ExecutableCompilationUnit::instantiate
(this=0x7f29b40c9bc0, engine=engine@entry=0x564754c84450) at jsruntime/
qv4executablecompilationunit.cpp:560
#36 0x00007f29e3c0e1a9 in QQmlScriptData::scriptValueForContext
(this=0x7f29b40c9eb0, parentQmlContextData=<optimized out>) at ../../include/
QtQml/5.15.2/QtQml/private/../../../../../src/qml/qml/ftw/qqmlrefcount_p.h:96
#37 0x00007f29e3c0e3a5 in QQmlScriptData::scriptValueForContext
(this=this@entry=0x7f29b40c9eb0, parentQmlContextData=<optimized out>) at qml/
qqmlscriptdata.cpp:155
#38 0x00007f29e3ca9af2 in QQmlObjectCreator::create
(this=this@entry=0x7ffd5f0822b0, subComponentIndex=subComponentIndex@entry=-1,
parent=parent@entry=0x0, interrupt=interrupt@entry=0x0, flags=flags@entry=1)
at qml/qqmlobjectcreator.cpp:198
#39 0x00007f29e3ca8f4f in QQmlObjectCreator::createInstance
(this=0x7ffd5f082550, index=0, parent=0x0, isContextObject=<optimized out>) at
qml/qqmlobjectcreator.cpp:1231
#40 0x00007f29e3ca98bf in QQmlObjectCreator::create
(this=this@entry=0x7ffd5f082550, subComponentIndex=subComponentIndex@entry=-1,
parent=parent@entry=0x0, interrupt=interrupt@entry=0x0, flags=flags@entry=1)
at qml/qqmlobjectcreator.cpp:204
#41 0x00007f29e3ca8f4f in QQmlObjectCreator::createInstance
(this=0x564755302800, index=2, parent=0x5647552b9920,
isContextObject=<optimized out>) at qml/qqmlobjectcreator.cpp:1231
#42 0x00007f29e3cab848 in QQmlObjectCreator::setPropertyBinding
(this=0x564755302800, bindingProperty=0x7f29b41805d8, binding=0x7f29d4095744)
at /usr/include/x86_64-linux-gnu/qt5/QtCore/qendian.h:290
#43 0x00007f29e3cabcf4 in QQmlObjectCreator::setupBindings
(this=0x564755302800, applyDeferredBindings=false) at qml/
qqmlobjectcreator.cpp:798
#44 0x00007f29e3ca7c8b in QQmlObjectCreator::populateInstance
(this=this@entry=0x564755302800, index=0, index@entry=1,
instance=0x5647549ce510, bindingTarget=0x5647549ce510,
valueTypeProperty=valueTypeProperty@entry=0x0) at qml/qqmlobjectcreator.cpp:
1555
#45 0x00007f29e3ca8c55 in QQmlObjectCreator::createInstance
(this=0x564755302800, index=<optimized out>, parent=<optimized out>,
isContextObject=<optimized out>) at qml/qqmlobjectcreator.cpp:1348
#46 0x00007f29e3cab848 in QQmlObjectCreator::setPropertyBinding
(this=0x564755302800, bindingProperty=0x7f29b41966e8, binding=0x7f29d4095650)
at /usr/include/x86_64-linux-gnu/qt5/QtCore/qendian.h:290
#47 0x00007f29e3cabcf4 in QQmlObjectCreator::setupBindings
(this=0x564755302800, applyDeferredBindings=false) at qml/
qqmlobjectcreator.cpp:798
#48 0x00007f29e3ca7c8b in QQmlObjectCreator::populateInstance
(this=this@entry=0x564755302800, index=-1, index@entry=0, instance=0x0,
bindingTarget=0x0, valueTypeProperty=valueTypeProperty@entry=0x0) at qml/
qqmlobjectcreator.cpp:1555
#49 0x00007f29e3ca8c55 in QQmlObjectCreator::createInstance
(this=0x564755302800, index=<optimized out>, parent=<optimized out>,
isContextObject=<optimized out>) at qml/qqmlobjectcreator.cpp:1348
#50 0x00007f29e3ca98bf in QQmlObjectCreator::create
(this=this@entry=0x564755302800, subComponentIndex=<optimized out>,
parent=parent@entry=0x0, interrupt=interrupt@entry=0x0, flags=flags@entry=1)
at qml/qqmlobjectcreator.cpp:204
#51 0x00007f29e3c3a89b in QQmlComponentPrivate::beginCreate
(this=0x5647552b6e80, context=<optimized out>) at /usr/include/x86_64-linux-
gnu/qt5/QtCore/qscopedpointer.h:116
#52 0x00007f29e3c3bc7a in QQmlComponent::create (this=0x564754b7cac0,
context=<optimized out>) at qml/qqmlcomponent.cpp:818
#53 0x00007f29e6ae0553 in
KWin::TabBox::TabBoxHandlerPrivate::createSwitcherItem
(this=this@entry=0x564754b9f400, desktopMode=desktopMode@entry=false) at ./
tabbox/tabboxhandler.cpp:276
#54 0x00007f29e6ae10e2 in KWin::TabBox::TabBoxHandlerPrivate::show
(this=0x564754b9f400) at ./tabbox/tabboxhandler.cpp:309
#55 0x00007f29e6ae1339 in KWin::TabBox::TabBoxHandler::show
(this=0x564754c968e0) at ./tabbox/tabboxhandler.cpp:375
#56 0x00007f29e566e580 in doActivate<false> (sender=0x564754bd2c88,
signal_index=3, argv=argv@entry=0x7ffd5f083580) at kernel/qobject.cpp:3898
#57 0x00007f29e56678a0 in QMetaObject::activate (sender=<optimized out>,
m=m@entry=0x7f29e58cd2a0 <QTimer::staticMetaObject>,
local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffd5f083580)
at kernel/qobject.cpp:3946
#58 0x00007f29e567245a in QTimer::timeout (this=<optimized out>, _t1=...) at
.moc/moc_qtimer.cpp:205
#59 0x00007f29e5663ecf in QObject::event (this=0x564754bd2c88,
e=0x7ffd5f0836f0) at kernel/qobject.cpp:1336
#60 0x00007f29e60f915f in QApplicationPrivate::notify_helper (this=<optimized
out>, receiver=0x564754bd2c88, e=0x7ffd5f0836f0) at kernel/qapplication.cpp:
3632
#61 0x00007f29e5637f6a in QCoreApplication::notifyInternal2
(receiver=0x564754bd2c88, event=0x7ffd5f0836f0) at kernel/
qcoreapplication.cpp:1063
#62 0x00007f29e568e883 in QTimerInfoList::activateTimers
(this=this@entry=0x564754983248) at kernel/qtimerinfo_unix.cpp:643
#63 0x00007f29e568bfbc in QEventDispatcherUNIXPrivate::activateTimers
(this=this@entry=0x5647549831c0) at kernel/qeventdispatcher_unix.cpp:249
#64 0x00007f29e568cd17 in QEventDispatcherUNIX::processEvents (this=<optimized
out>, flags=...) at kernel/qeventdispatcher_unix.cpp:516
#65 0x00007f29df0efb7e in QXcbUnixEventDispatcher::processEvents
(this=0x564754998940, flags=...) at qxcbeventdispatcher.cpp:60
#66 0x00007f29e563692b in QEventLoop::exec (this=this@entry=0x7ffd5f083890,
flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/
qflags.h:69
#67 0x00007f29e563eba0 in QCoreApplication::exec () at ../../include/
QtCore/../../src/corelib/global/qflags.h:121
#68 0x0000564753f87f59 in main (argc=<optimized out>, argv=0x7ffd5f083b18) at
./main_x11.cpp:484
[Inferior 1 (process 133770) detached]
#985994#30
Date:
2021-04-10 02:34:25 UTC
From:
To:
Application: KWin (kwin_x11), signal: Segmentation fault

[KCrash Handler]
#4  0x00007fb3b1729e08 in memcpy (__len=1, __src=<synthetic pointer>,
__dest=0x0) at /usr/include/x86_64-linux-gnu/bits/string_fortified.h:34
#5  JSC::AssemblerBuffer::putIntegralUnchecked<signed char>
(this=0x7fb3b2cba660 <_IO_stdfile_2_lock>, value=15 '\017') at ../3rdparty/
masm/assembler/AssemblerBuffer.h:105
#6  0x00007fb3b18383cc in JSC::AssemblerBuffer::putByteUnchecked (value=15
'\017', this=0x7fb3b2cba660 <_IO_stdfile_2_lock>) at ../3rdparty/masm/
assembler/AssemblerBuffer.h:109
#7  JSC::X86Assembler::X86InstructionFormatter::twoByteOp (offset=0, scale=0,
index=JSC::X86Registers::eax, base=JSC::X86Registers::edi, reg=1,
opcode=JSC::X86Assembler::OP2_MOVZX_GvEb, this=0x7fb3b2cba660
<_IO_stdfile_2_lock>) at ../3rdparty/masm/assembler/X86Assembler.h:2229
#8  JSC::X86Assembler::movzbl_mr (dst=JSC::X86Registers::ecx, scale=0,
index=JSC::X86Registers::eax, base=JSC::X86Registers::edi, offset=0,
this=0x7fb3b2cba660 <_IO_stdfile_2_lock>) at ../3rdparty/masm/assembler/
X86Assembler.h:1356
#9  JSC::MacroAssemblerX86Common::load8 (dest=JSC::X86Registers::ecx,
address=..., this=0x7fb3b2cba660 <_IO_stdfile_2_lock>) at ../3rdparty/masm/
assembler/MacroAssemblerX86Common.h:553
#10 JSC::Yarr::YarrGenerator<(JSC::Yarr::YarrJITCompileMode)0>::readCharacter
(this=0x7fb3b2cba660 <_IO_stdfile_2_lock>, negativeCharacterOffset=...,
resultReg=JSC::X86Registers::ecx, indexReg=<optimized out>) at ../3rdparty/
masm/yarr/YarrJIT.cpp:580
#11 0x0000001e00000009 in ?? ()
#12 0x00007fb3a40241c0 in ?? ()
#13 0x00007fb3aa03b000 in ?? ()
#14 0x0000564137b0ac80 in ?? ()
#15 0x00007fb3aa03b000 in ?? ()
#16 0x0000564137b0ac80 in ?? ()
#17 0x00007fb3b1937cc0 in vtable for
JSC::LinkBuffer<JSC::MacroAssembler<JSC::MacroAssemblerX86_64> > () from /usr/
lib/x86_64-linux-gnu/libQt5Qml.so.5
#18 0x0000564137b0ac80 in ?? ()
#19 0x00000000000002c4 in ?? ()
#20 0x00007fb3aa03b000 in ?? ()
#21 0x00007ffdf0bb0bc0 in ?? ()
#22 0x00007ffdf0bb0b28 in ?? ()
#23 0x00007ffdf0bb0e80 in ?? ()
#24 0xb7c9d33a9167ea00 in ?? ()
#25 0x0000000000000080 in ?? ()
#26 0x0000000000000001 in ?? ()
#27 0x00007ffdf0bb0d40 in ?? ()
#28 0x0000564137b246b0 in ?? ()
#29 0x00005641373574d0 in ?? ()
#30 0x00007fb3b182583c in JSC::Yarr::jitCompile (pattern=...,
charSize=(unknown: 0xf0bb0bc0), charSize@entry=JSC::Yarr::Char16,
vm=0x7fb3aa03b000, vm@entry=0x5641373574d0, codeBlock=...,
mode=mode@entry=JSC::Yarr::IncludeSubpatterns) at ../3rdparty/masm/yarr/
YarrJIT.cpp:4021
#31 0x00007fb3b167f460 in QV4::Heap::RegExp::init (this=0x7fb3a1271600,
engine=engine@entry=0x5641373574d0, pattern=..., flags=4038790456,
flags@entry=4038790776) at jsruntime/qv4regexp.cpp:224
#32 0x00007fb3b167f64c in QV4::MemoryManager::alloc<QV4::RegExp,
QV4::ExecutionEngine*, QString, unsigned int> (this=<optimized out>) at
jsruntime/qv4value_p.h:101
#33 QV4::RegExp::create (engine=engine@entry=0x5641373574d0, pattern=...,
flags=4038790776, flags@entry=1) at jsruntime/qv4regexp.cpp:199
#34 0x00007fb3b16c64a6 in QV4::ExecutableCompilationUnit::linkToEngine
(this=this@entry=0x7fb3801082d0, engine=engine@entry=0x5641373574d0) at
jsruntime/qv4executablecompilationunit.cpp:160
#35 0x00007fb3b16c93a3 in QV4::ExecutableCompilationUnit::instantiate
(this=0x7fb3801082d0, engine=engine@entry=0x5641373574d0) at jsruntime/
qv4executablecompilationunit.cpp:560
#36 0x00007fb3b173c1a9 in QQmlScriptData::scriptValueForContext
(this=0x7fb3801085c0, parentQmlContextData=<optimized out>) at ../../include/
QtQml/5.15.2/QtQml/private/../../../../../src/qml/qml/ftw/qqmlrefcount_p.h:96
#37 0x00007fb3b173c3a5 in QQmlScriptData::scriptValueForContext
(this=this@entry=0x7fb3801085c0, parentQmlContextData=<optimized out>) at qml/
qqmlscriptdata.cpp:155
#38 0x00007fb3b17d7af2 in QQmlObjectCreator::create
(this=this@entry=0x7ffdf0bb11e0, subComponentIndex=subComponentIndex@entry=-1,
parent=parent@entry=0x0, interrupt=interrupt@entry=0x0, flags=flags@entry=1)
at qml/qqmlobjectcreator.cpp:198
#39 0x00007fb3b17d6f4f in QQmlObjectCreator::createInstance
(this=0x7ffdf0bb1480, index=0, parent=0x0, isContextObject=<optimized out>) at
qml/qqmlobjectcreator.cpp:1231
#40 0x00007fb3b17d78bf in QQmlObjectCreator::create
(this=this@entry=0x7ffdf0bb1480, subComponentIndex=subComponentIndex@entry=-1,
parent=parent@entry=0x0, interrupt=interrupt@entry=0x0, flags=flags@entry=1)
at qml/qqmlobjectcreator.cpp:204
#41 0x00007fb3b17d6f4f in QQmlObjectCreator::createInstance
(this=0x564137a75150, index=2, parent=0x564137a27c90,
isContextObject=<optimized out>) at qml/qqmlobjectcreator.cpp:1231
#42 0x00007fb3b17d9848 in QQmlObjectCreator::setPropertyBinding
(this=0x564137a75150, bindingProperty=0x7fb380180008, binding=0x7fb3a8016744)
at /usr/include/x86_64-linux-gnu/qt5/QtCore/qendian.h:290
#43 0x00007fb3b17d9cf4 in QQmlObjectCreator::setupBindings
(this=0x564137a75150, applyDeferredBindings=false) at qml/
qqmlobjectcreator.cpp:798
#44 0x00007fb3b17d5c8b in QQmlObjectCreator::populateInstance
(this=this@entry=0x564137a75150, index=0, index@entry=1,
instance=0x5641370bea60, bindingTarget=0x5641370bea60,
valueTypeProperty=valueTypeProperty@entry=0x0) at qml/qqmlobjectcreator.cpp:
1555
#45 0x00007fb3b17d6c55 in QQmlObjectCreator::createInstance
(this=0x564137a75150, index=<optimized out>, parent=<optimized out>,
isContextObject=<optimized out>) at qml/qqmlobjectcreator.cpp:1348
#46 0x00007fb3b17d9848 in QQmlObjectCreator::setPropertyBinding
(this=0x564137a75150, bindingProperty=0x7fb380196798, binding=0x7fb3a8016650)
at /usr/include/x86_64-linux-gnu/qt5/QtCore/qendian.h:290
#47 0x00007fb3b17d9cf4 in QQmlObjectCreator::setupBindings
(this=0x564137a75150, applyDeferredBindings=false) at qml/
qqmlobjectcreator.cpp:798
#48 0x00007fb3b17d5c8b in QQmlObjectCreator::populateInstance
(this=this@entry=0x564137a75150, index=-1, index@entry=0, instance=0x0,
bindingTarget=0x0, valueTypeProperty=valueTypeProperty@entry=0x0) at qml/
qqmlobjectcreator.cpp:1555
#49 0x00007fb3b17d6c55 in QQmlObjectCreator::createInstance
(this=0x564137a75150, index=<optimized out>, parent=<optimized out>,
isContextObject=<optimized out>) at qml/qqmlobjectcreator.cpp:1348
#50 0x00007fb3b17d78bf in QQmlObjectCreator::create
(this=this@entry=0x564137a75150, subComponentIndex=<optimized out>,
parent=parent@entry=0x0, interrupt=interrupt@entry=0x0, flags=flags@entry=1)
at qml/qqmlobjectcreator.cpp:204
#51 0x00007fb3b176889b in QQmlComponentPrivate::beginCreate
(this=0x564137a5bbf0, context=<optimized out>) at /usr/include/x86_64-linux-
gnu/qt5/QtCore/qscopedpointer.h:116
#52 0x00007fb3b1769c7a in QQmlComponent::create (this=0x5641370987f0,
context=<optimized out>) at qml/qqmlcomponent.cpp:818
#53 0x00007fb3b460e553 in
KWin::TabBox::TabBoxHandlerPrivate::createSwitcherItem
(this=this@entry=0x56413709e0f0, desktopMode=desktopMode@entry=false) at ./
tabbox/tabboxhandler.cpp:276
#54 0x00007fb3b460f0e2 in KWin::TabBox::TabBoxHandlerPrivate::show
(this=0x56413709e0f0) at ./tabbox/tabboxhandler.cpp:309
#55 0x00007fb3b460f339 in KWin::TabBox::TabBoxHandler::show
(this=0x5641372902c0) at ./tabbox/tabboxhandler.cpp:375
#56 0x00007fb3b319c580 in doActivate<false> (sender=0x56413709cd98,
signal_index=3, argv=argv@entry=0x7ffdf0bb24b0) at kernel/qobject.cpp:3898
#57 0x00007fb3b31958a0 in QMetaObject::activate (sender=<optimized out>,
m=m@entry=0x7fb3b33fb2a0 <QTimer::staticMetaObject>,
local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffdf0bb24b0)
at kernel/qobject.cpp:3946
#58 0x00007fb3b31a045a in QTimer::timeout (this=<optimized out>, _t1=...) at
.moc/moc_qtimer.cpp:205
#59 0x00007fb3b3191ecf in QObject::event (this=0x56413709cd98,
e=0x7ffdf0bb2620) at kernel/qobject.cpp:1336
#60 0x00007fb3b3c2715f in QApplicationPrivate::notify_helper (this=<optimized
out>, receiver=0x56413709cd98, e=0x7ffdf0bb2620) at kernel/qapplication.cpp:
3632
#61 0x00007fb3b3165f6a in QCoreApplication::notifyInternal2
(receiver=0x56413709cd98, event=0x7ffdf0bb2620) at kernel/
qcoreapplication.cpp:1063
#62 0x00007fb3b31bc883 in QTimerInfoList::activateTimers
(this=this@entry=0x5641370734e8) at kernel/qtimerinfo_unix.cpp:643
#63 0x00007fb3b31b9fbc in QEventDispatcherUNIXPrivate::activateTimers
(this=this@entry=0x564137073460) at kernel/qeventdispatcher_unix.cpp:249
#64 0x00007fb3b31bad17 in QEventDispatcherUNIX::processEvents (this=<optimized
out>, flags=...) at kernel/qeventdispatcher_unix.cpp:516
#65 0x00007fb3acc1db7e in QXcbUnixEventDispatcher::processEvents
(this=0x564137088d80, flags=...) at qxcbeventdispatcher.cpp:60
#66 0x00007fb3b316492b in QEventLoop::exec (this=this@entry=0x7ffdf0bb27c0,
flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/
qflags.h:69
#67 0x00007fb3b316cba0 in QCoreApplication::exec () at ../../include/
QtCore/../../src/corelib/global/qflags.h:121
#68 0x000056413541af59 in main (argc=<optimized out>, argv=0x7ffdf0bb2a48) at
./main_x11.cpp:484
[Inferior 1 (process 133796) detached]
#985994#35
Date:
2021-04-10 11:56:42 UTC
From:
To:
Hello Russel,
thank you for the detailed backtraces.
Unfortunately they point into Qt's javascript module,
finally trying to copy memory to a null pointer.

I have not found a hint to similar crashes in
upstream bug tracker.

Could you please provide which theme you are using,
or if there are maybe some third party extensions in use?

Maybe you are aware of some not widely used settings
that you changed, which might be related?

Kind regards,
Bernhard
#985994#40
Date:
2021-04-10 13:09:24 UTC
From:
To:
Thanks for spending so much time on this.

Breeze Dark theme.  I changed many settings but can't think of anything that's
related to kwin apart from the theme and colors.

It's a pity there isn't a way to dump out all the settings in some well known
format (XML, JSON, whatever) so I could run a diff between my settings and
default settings and then do a binary search for the problem.
#985994#45
Date:
2022-04-29 12:38:07 UTC
From:
To:
Hi,

I have a very similar bug where kwin-x11 crashes, I get logged out, but have
to manually kill kwin. But that bug appeared just recently (I'm using kwin-x11
5.24.4-1 from unstable).

Usually after logging in I use a hotkey to go through all windows that want
attention (after logging in it is all of them) and around half the time I do
this kwin crashes. This maybe happens because I switch too fast through the
windows? I haven't found any error yet, but this could be related.


Best regards
Matthias