SUMMARY
I opened settings of System Monitor Sensor widget added to desktop, clicked on "Sensor details" section in the left side and added "Package id 0" to "Chart sensros" list via double click. Then Plasma crashed.

Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.19.80
KDE Frameworks Version: 5.71.0
Qt Version: 5.14.2

Thread 11 (Thread 0x7f2ab4eed700 (LWP 20257)):
#0  0x00007f2b095f6bf9 in __GI___poll (fds=0x7f2a940029e0, nfds=1, timeout=-1)
    at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f2b02f175c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f2b02f176dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f2b09f5d7ac in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f2a94000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007f2b09efcd2a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f2ab4eecd80, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#5  0x00007f2b09d0d757 in QThread::exec() (this=this@entry=0x561aa1994750) at thread/qthread.cpp:536
#6  0x00007f2b0d8c0fc5 in QQmlThreadPrivate::run() (this=0x561aa1994750) at qml/ftw/qqmlthread.cpp:155
#7  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x561aa1994750)
    at thread/qthread_unix.cpp:342
#8  0x00007f2b066316db in start_thread (arg=0x7f2ab4eed700) at pthread_create.c:463
#9  0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 10 (Thread 0x7f2ab6ea4700 (LWP 20246)):
#0  0x00007f2b095f6bf9 in __GI___poll (fds=0x7f2a9c002de0, nfds=1, timeout=9986)
    at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f2b02f175c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f2b02f176dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f2b09f5d7ac in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f2a9c000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007f2b09efcd2a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f2ab6ea3da0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#5  0x00007f2b09d0d757 in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:536
#6  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x7f2ac80064a0)
    at thread/qthread_unix.cpp:342
#7  0x00007f2b066316db in start_thread (arg=0x7f2ab6ea4700) at pthread_create.c:463
#8  0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x7f2ab82ec700 (LWP 20237)):
#0  0x00007f2b066379f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561a9f467dd4) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007f2b066379f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x561a9f467d80, cond=0x561a9f467da8) at pthread_cond_wait.c:502
#2  0x00007f2b066379f3 in __pthread_cond_wait (cond=0x561a9f467da8, mutex=0x561a9f467d80)
    at pthread_cond_wait.c:655
#3  0x00007f2b09d151db in QWaitConditionPrivate::wait(QDeadlineTimer) (deadline=..., this=0x561a9f467d80) at thread/qwaitcondition_unix.cpp:146
#4  0x00007f2b09d151db in QWaitCondition::wait(QMutex*, QDeadlineTimer) (this=<optimized out>, mutex=0x7f2af400b310, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f2b09d15359 in QWaitCondition::wait(QMutex*, unsigned long) (this=this@entry=0x7f2af400b318, mutex=mutex@entry=0x7f2af400b310, time=time@entry=18446744073709551615)
    at thread/qwaitcondition_unix.cpp:208
#6  0x00007f2b0de14233 in QSGRenderThreadEventQueue::takeEvent(bool) (wait=true, this=0x7f2af400b308)
    at scenegraph/qsgthreadedrenderloop.cpp:255
#7  0x00007f2b0de14233 in QSGRenderThread::processEventsAndWaitForMore() (this=this@entry=0x7f2af400b270) at scenegraph/qsgthreadedrenderloop.cpp:905
#8  0x00007f2b0de14691 in QSGRenderThread::run() (this=0x7f2af400b270)
    at scenegraph/qsgthreadedrenderloop.cpp:1000
#9  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x7f2af400b270)
    at thread/qthread_unix.cpp:342
#10 0x00007f2b066316db in start_thread (arg=0x7f2ab82ec700) at pthread_create.c:463
#11 0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f2af3fff700 (LWP 20221)):
#0  0x00007f2b095f6bf9 in __GI___poll (fds=0x7f2aec012a00, nfds=4, timeout=-1)
    at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f2b02f175c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f2b02f176dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f2b09f5d7ac in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f2aec000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007f2b09efcd2a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f2af3ffed70, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#5  0x00007f2b09d0d757 in QThread::exec() (this=this@entry=0x7f2b0be83da0 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread.cpp:536
#6  0x00007f2b0bc0b555 in QDBusConnectionManager::run() (this=0x7f2b0be83da0 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:179
#7  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x7f2b0be83da0 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:342
#8  0x00007f2b066316db in start_thread (arg=0x7f2af3fff700) at pthread_create.c:463
#9  0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f2ae37bd700 (LWP 20223)):
#0  0x00007f2b066379f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561a9c107b98) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007f2b066379f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x561a9c107b48, cond=0x561a9c107b70) at pthread_cond_wait.c:502
#2  0x00007f2b066379f3 in __pthread_cond_wait (cond=0x561a9c107b70, mutex=0x561a9c107b48)
    at pthread_cond_wait.c:655
#3  0x00007f2ae8e71ecb in cnd_wait (mtx=0x561a9c107b48, cond=0x561a9c107b70)
    at ../include/c11/threads_posix.h:155
#4  0x00007f2ae8e71ecb in util_queue_thread_func (input=input@entry=0x561a9c34cbf0)
    at ../src/util/u_queue.c:258
#5  0x00007f2ae8e71ac7 in impl_thrd_routine (p=<optimized out>) at ../include/c11/threads_posix.h:87
#6  0x00007f2b066316db in start_thread (arg=0x7f2ae37bd700) at pthread_create.c:463
#7  0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f2afab09700 (LWP 20220)):
#0  0x00007f2b095f6bf9 in __GI___poll (fds=0x7f2afab08ca8, nfds=1, timeout=-1)
    at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f2b0ea27747 in  () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f2b0ea2936a in xcb_wait_for_event () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f2afd2cafd0 in QXcbEventQueue::run() (this=0x561a9bcd37b0) at qxcbeventqueue.cpp:228
#4  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x561a9bcd37b0)
    at thread/qthread_unix.cpp:342
#5  0x00007f2b066316db in start_thread (arg=0x7f2afab09700) at pthread_create.c:463
#6  0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f2acf756700 (LWP 20227)):
#0  0x00007f2b095f6bf9 in __GI___poll (fds=0x7f2ac804b280, nfds=4, timeout=30986)
    at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f2b02f175c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f2b02f176dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f2b09f5d7ac in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f2ac8000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007f2b09efcd2a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f2acf755d30, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#5  0x00007f2b09d0d757 in QThread::exec() (this=this@entry=0x7f2ae408ac00) at thread/qthread.cpp:536
#6  0x00007f2b0dd56b06 in QQuickPixmapReader::run() (this=0x7f2ae408ac00)
    at util/qquickpixmapcache.cpp:987
#7  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x7f2ae408ac00)
    at thread/qthread_unix.cpp:342
#8  0x00007f2b066316db in start_thread (arg=0x7f2acf756700) at pthread_create.c:463
#9  0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f2a9abd2700 (LWP 20258)):
#0  0x00007f2b066379f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561aa0d60250) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007f2b066379f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x561aa0d60200, cond=0x561aa0d60228) at pthread_cond_wait.c:502
#2  0x00007f2b066379f3 in __pthread_cond_wait (cond=0x561aa0d60228, mutex=0x561aa0d60200)
    at pthread_cond_wait.c:655
#3  0x00007f2b09d151db in QWaitConditionPrivate::wait(QDeadlineTimer) (deadline=..., this=0x561aa0d60200) at thread/qwaitcondition_unix.cpp:146
#4  0x00007f2b09d151db in QWaitCondition::wait(QMutex*, QDeadlineTimer) (this=<optimized out>, mutex=0x561aa10e1760, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f2b09d15359 in QWaitCondition::wait(QMutex*, unsigned long) (this=this@entry=0x561aa10e1768, mutex=mutex@entry=0x561aa10e1760, time=time@entry=18446744073709551615)
    at thread/qwaitcondition_unix.cpp:208
#6  0x00007f2b0de14233 in QSGRenderThreadEventQueue::takeEvent(bool) (wait=true, this=0x561aa10e1758)
    at scenegraph/qsgthreadedrenderloop.cpp:255
#7  0x00007f2b0de14233 in QSGRenderThread::processEventsAndWaitForMore() (this=this@entry=0x561aa10e16c0) at scenegraph/qsgthreadedrenderloop.cpp:905
#8  0x00007f2b0de14691 in QSGRenderThread::run() (this=0x561aa10e16c0)
    at scenegraph/qsgthreadedrenderloop.cpp:1000
#9  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x561aa10e16c0)
    at thread/qthread_unix.cpp:342
#10 0x00007f2b066316db in start_thread (arg=0x7f2a9abd2700) at pthread_create.c:463
#11 0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f2af25a2700 (LWP 20222)):
#0  0x00007f2b095f6bf9 in __GI___poll (fds=0x7f2ae40029e0, nfds=1, timeout=-1)
    at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f2b02f175c9 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f2b02f176dc in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f2b09f5d7ac in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f2ae4000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007f2b09efcd2a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f2af25a1d80, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#5  0x00007f2b09d0d757 in QThread::exec() (this=this@entry=0x561a9bdde160) at thread/qthread.cpp:536
#6  0x00007f2b0d8c0fc5 in QQmlThreadPrivate::run() (this=0x561a9bdde160) at qml/ftw/qqmlthread.cpp:155
#7  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x561a9bdde160)
    at thread/qthread_unix.cpp:342
#8  0x00007f2b066316db in start_thread (arg=0x7f2af25a2700) at pthread_create.c:463
#9  0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f2ad4822700 (LWP 20225)):
#0  0x00007f2b066379f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561a9c4739a4) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007f2b066379f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x561a9c473950, cond=0x561a9c473978) at pthread_cond_wait.c:502
#2  0x00007f2b066379f3 in __pthread_cond_wait (cond=0x561a9c473978, mutex=0x561a9c473950)
    at pthread_cond_wait.c:655
#3  0x00007f2b09d151db in QWaitConditionPrivate::wait(QDeadlineTimer) (deadline=..., this=0x561a9c473950) at thread/qwaitcondition_unix.cpp:146
#4  0x00007f2b09d151db in QWaitCondition::wait(QMutex*, QDeadlineTimer) (this=<optimized out>, mutex=0x7f2af4007e80, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f2b09d15359 in QWaitCondition::wait(QMutex*, unsigned long) (this=this@entry=0x7f2af4007e88, mutex=mutex@entry=0x7f2af4007e80, time=time@entry=18446744073709551615)
    at thread/qwaitcondition_unix.cpp:208
#6  0x00007f2b0de14233 in QSGRenderThreadEventQueue::takeEvent(bool) (wait=true, this=0x7f2af4007e78)
    at scenegraph/qsgthreadedrenderloop.cpp:255
#7  0x00007f2b0de14233 in QSGRenderThread::processEventsAndWaitForMore() (this=this@entry=0x7f2af4007de0) at scenegraph/qsgthreadedrenderloop.cpp:905
#8  0x00007f2b0de14691 in QSGRenderThread::run() (this=0x7f2af4007de0)
    at scenegraph/qsgthreadedrenderloop.cpp:1000
#9  0x00007f2b09d0ec2c in QThreadPrivate::start(void*) (arg=0x7f2af4007de0)
    at thread/qthread_unix.cpp:342
#10 0x00007f2b066316db in start_thread (arg=0x7f2ad4822700) at pthread_create.c:463
#11 0x00007f2b0960388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f2b0ff11c80 (LWP 20215)):
#0  0x00007f2b09520e97 in __GI_raise (sig=sig@entry=11) at ../sysdeps/unix/sysv/linux/raise.c:51
#1  0x00007f2b0ca19053 in KCrash::defaultCrashHandler(int) (sig=11) at ./src/kcrash.cpp:442
#2  0x00007f2b09520f20 in <signal handler called> () at /lib/x86_64-linux-gnu/libc.so.6
#3  0x00007f2b0d74e66a in QQmlData::wasDeleted(QObject const*) (object=0x561a9c146e60)
    at ../../include/QtQml/5.14.2/QtQml/private/../../../../../src/qml/qml/qqmldata_p.h:338
#4  0x00007f2b0d74e66a in QV4::QObjectWrapper::getQmlProperty(QV4::ExecutionEngine*, QQmlContextData*, QObject*, QV4::String*, QV4::QObjectWrapper::RevisionMode, bool*, QQmlPropertyData**) (engine=engine@entry=0x561a9bdf2dc0, qmlContext=qmlContext@entry=0x561aa17d2320, object=0x561a9c146e60, name=0x7f2af1963738, revisionMode=revisionMode@entry=QV4::QObjectWrapper::CheckRevision, hasProperty=hasProperty@entry=0x7ffdf04c07a8, property=0x7ffdf04c07b0) at jsruntime/qv4qobjectwrapper.cpp:360
#5  0x00007f2b0d7267ab in QV4::QQmlContextWrapper::getPropertyAndBase(QV4::QQmlContextWrapper const*, QV4::PropertyKey, QV4::Value const*, bool*, QV4::Value*, QV4::Lookup*) (resource=<optimized out>, id=..., receiver=<optimized out>, hasProperty=0x7ffdf04c0837, base=0x0, lookup=0x0)
    at jsruntime/qv4qmlcontext.cpp:316
#6  0x00007f2b0d6cf57e in QV4::Object::get(QV4::PropertyKey, QV4::Value const*, bool*) const (hasProperty=0x7ffdf04c0837, receiver=0x7f2af1963728, id=..., this=<optimized out>)
    at jsruntime/qv4object_p.h:314
#7  0x00007f2b0d6cf57e in QV4::ExecutionContext::getProperty(QV4::String*) (this=0x7f2af19636b8, name=0x7f2af1963720) at jsruntime/qv4context.cpp:362
#8  0x00007f2b0d77edbf in QV4::Runtime::TypeofName::call(QV4::ExecutionEngine*, int) (engine=0x561a9bdf2dc0, nameIndex=<optimized out>) at jsruntime/qv4runtime.cpp:1647
#9  0x00007f2ab6eef4b4 in  ()
#10 0x0000000000000000 in  ()