plasmashell process hangs and uses 100% of a CPU core

$ gdb plasmashell 1326
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Reading symbols from plasmashell...Reading symbols from /usr/lib/debug/usr/bin/plasmashell-5.11.5-2.fc27.x86_64.debug...done.
done.
Attaching to program: /usr/bin/plasmashell, process 1326
[New LWP 1404]
[New LWP 1579]
[New LWP 1630]
[New LWP 1706]
[New LWP 1753]
[New LWP 1811]
[New LWP 1921]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00007f339e7bc7c5 in QV4::PersistentValueStorage::allocate (this=0x55711959f670) at jsruntime/qv4persistent.cpp:189
189             if (p->header.freeList != -1)
(gdb) thread apply all backtrace

Thread 8 (Thread 0x7f32cb85d700 (LWP 1921)):
#0  0x00007f3399a3136b in __GI___poll (fds=0x7f32c4006070, nfds=1, timeout=3499955) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f3391cdaed9 in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7f32c4006070, timeout=<optimized out>, 
    context=0x7f32c4000bf0) at gmain.c:4187
#2  g_main_context_iterate (context=context@entry=0x7f32c4000bf0, block=block@entry=1, dispatch=dispatch@entry=1, 
    self=<optimized out>) at gmain.c:3881
#3  0x00007f3391cdafec in g_main_context_iteration (context=0x7f32c4000bf0, may_block=may_block@entry=1) at gmain.c:3947
#4  0x00007f339a89c33f in QEventDispatcherGlib::processEvents (this=0x7f32c4000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007f339a84a0ea in QEventLoop::exec (this=this@entry=0x7f32cb85cc20, flags=..., flags@entry=...) at kernel/qeventloop.cpp:212
#6  0x00007f339a69b8ba in QThread::exec (this=<optimized out>) at thread/qthread.cpp:515
#7  0x00007f32ce1cd577 in KCupsConnection::run (this=0x55711c4a05e0)
    at /usr/src/debug/kde-print-manager-17.08.1-1.fc27.x86_64/libkcups/KCupsConnection.cpp:304
#8  0x00007f339a69fb92 in QThreadPrivate::start (arg=0x55711c4a05e0) at thread/qthread_unix.cpp:368
#9  0x00007f3398d6d61b in start_thread (arg=0x7f32cb85d700) at pthread_create.c:465
---Type <return> to continue, or q <return> to quit---
#10 0x00007f3399a3d91f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f32e05db700 (LWP 1811)):
#0  0x00007f3399a3136b in __GI___poll (fds=0x7f32d80050f0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f3391cdaed9 in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7f32d80050f0, timeout=<optimized out>, 
    context=0x7f32d8000bf0) at gmain.c:4187
#2  g_main_context_iterate (context=context@entry=0x7f32d8000bf0, block=block@entry=1, dispatch=dispatch@entry=1, 
    self=<optimized out>) at gmain.c:3881
#3  0x00007f3391cdafec in g_main_context_iteration (context=0x7f32d8000bf0, may_block=may_block@entry=1) at gmain.c:3947
#4  0x00007f339a89c33f in QEventDispatcherGlib::processEvents (this=0x7f32d8000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007f339a84a0ea in QEventLoop::exec (this=this@entry=0x7f32e05dabf0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:212
#6  0x00007f339a69b8ba in QThread::exec (this=this@entry=0x557119ee0ba0) at thread/qthread.cpp:515
#7  0x00007f339f49f1f6 in QQuickPixmapReader::run (this=0x557119ee0ba0) at util/qquickpixmapcache.cpp:868
#8  0x00007f339a69fb92 in QThreadPrivate::start (arg=0x557119ee0ba0) at thread/qthread_unix.cpp:368
#9  0x00007f3398d6d61b in start_thread (arg=0x7f32e05db700) at pthread_create.c:465
---Type <return> to continue, or q <return> to quit---
#10 0x00007f3399a3d91f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f336ffff700 (LWP 1753)):
#0  0x00007f3398d73c4b in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x7f33a1aba478 <QTWTF::pageheap_memory+57592>) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x7f33a1aba428 <QTWTF::pageheap_memory+57512>, 
    cond=0x7f33a1aba450 <QTWTF::pageheap_memory+57552>) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x7f33a1aba450 <QTWTF::pageheap_memory+57552>, mutex=0x7f33a1aba428 <QTWTF::pageheap_memory+57512>)
    at pthread_cond_wait.c:655
#3  0x00007f33a17c4604 in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x7f33a1aac380 <QTWTF::pageheap_memory>)
    at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#4  0x00007f33a17c4649 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>)
    at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#5  0x00007f3398d6d61b in start_thread (arg=0x7f336ffff700) at pthread_create.c:465
#6  0x00007f3399a3d91f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

---Type <return> to continue, or q <return> to quit---
Thread 5 (Thread 0x7f337a59f700 (LWP 1706)):
#0  0x00007f3399a3136b in __GI___poll (fds=0x7f3368003ce0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f3391cdaed9 in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7f3368003ce0, timeout=<optimized out>, 
    context=0x7f3368000bf0) at gmain.c:4187
#2  g_main_context_iterate (context=context@entry=0x7f3368000bf0, block=block@entry=1, dispatch=dispatch@entry=1, 
    self=<optimized out>) at gmain.c:3881
#3  0x00007f3391cdafec in g_main_context_iteration (context=0x7f3368000bf0, may_block=may_block@entry=1) at gmain.c:3947
#4  0x00007f339a89c33f in QEventDispatcherGlib::processEvents (this=0x7f3368000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007f339a84a0ea in QEventLoop::exec (this=this@entry=0x7f337a59ec40, flags=..., flags@entry=...) at kernel/qeventloop.cpp:212
#6  0x00007f339a69b8ba in QThread::exec (this=this@entry=0x5571195b24c0) at thread/qthread.cpp:515
#7  0x00007f339e9022a5 in QQmlThreadPrivate::run (this=0x5571195b24c0) at qml/ftw/qqmlthread.cpp:147
#8  0x00007f339a69fb92 in QThreadPrivate::start (arg=0x5571195b24c0) at thread/qthread_unix.cpp:368
#9  0x00007f3398d6d61b in start_thread (arg=0x7f337a59f700) at pthread_create.c:465
#10 0x00007f3399a3d91f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

---Type <return> to continue, or q <return> to quit---
Thread 4 (Thread 0x7f337bfff700 (LWP 1630)):
#0  0x00007f3399a3136b in __GI___poll (fds=0x7f3370004a00, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f3391cdaed9 in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7f3370004a00, timeout=<optimized out>, 
    context=0x7f3370000bf0) at gmain.c:4187
#2  g_main_context_iterate (context=context@entry=0x7f3370000bf0, block=block@entry=1, dispatch=dispatch@entry=1, 
    self=<optimized out>) at gmain.c:3881
#3  0x00007f3391cdafec in g_main_context_iteration (context=0x7f3370000bf0, may_block=may_block@entry=1) at gmain.c:3947
#4  0x00007f339a89c33f in QEventDispatcherGlib::processEvents (this=0x7f3370000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007f339a84a0ea in QEventLoop::exec (this=this@entry=0x7f337bffec40, flags=..., flags@entry=...) at kernel/qeventloop.cpp:212
#6  0x00007f339a69b8ba in QThread::exec (this=this@entry=0x55711939c4f0) at thread/qthread.cpp:515
#7  0x00007f339e9022a5 in QQmlThreadPrivate::run (this=0x55711939c4f0) at qml/ftw/qqmlthread.cpp:147
#8  0x00007f339a69fb92 in QThreadPrivate::start (arg=0x55711939c4f0) at thread/qthread_unix.cpp:368
#9  0x00007f3398d6d61b in start_thread (arg=0x7f337bfff700) at pthread_create.c:465
#10 0x00007f3399a3d91f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

---Type <return> to continue, or q <return> to quit---
Thread 3 (Thread 0x7f3381ec8700 (LWP 1579)):
#0  0x00007f3399a3136b in __GI___poll (fds=0x7f3374013150, nfds=4, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f3391cdaed9 in g_main_context_poll (priority=<optimized out>, n_fds=4, fds=0x7f3374013150, timeout=<optimized out>, 
    context=0x7f3374000bf0) at gmain.c:4187
#2  g_main_context_iterate (context=context@entry=0x7f3374000bf0, block=block@entry=1, dispatch=dispatch@entry=1, 
    self=<optimized out>) at gmain.c:3881
#3  0x00007f3391cdafec in g_main_context_iteration (context=0x7f3374000bf0, may_block=may_block@entry=1) at gmain.c:3947
#4  0x00007f339a89c33f in QEventDispatcherGlib::processEvents (this=0x7f3374000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007f339a84a0ea in QEventLoop::exec (this=this@entry=0x7f3381ec7c20, flags=..., flags@entry=...) at kernel/qeventloop.cpp:212



#6  0x00007f339a69b8ba in QThread::exec (
    this=this@entry=0x7f339af26060 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread.cpp:515
#7  0x00007f339acb2479 in QDBusConnectionManager::run (
    this=0x7f339af26060 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:178
#8  0x00007f339a69fb92 in QThreadPrivate::start (
    arg=0x7f339af26060 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:368
---Type <return> to continue, or q <return> to quit---
#9  0x00007f3398d6d61b in start_thread (arg=0x7f3381ec8700) at pthread_create.c:465
#10 0x00007f3399a3d91f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f338403e700 (LWP 1404)):
#0  0x00007f3399a3136b in __GI___poll (fds=fds@entry=0x7f338403db68, nfds=nfds@entry=1, timeout=timeout@entry=-1)
    at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f33a00abfe7 in poll (__timeout=-1, __nfds=1, __fds=0x7f338403db68) at /usr/include/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0x55711937c6a0, cond=cond@entry=0x55711937c6e0, vector=vector@entry=0x0, count=count@entry=0x0)
    at xcb_conn.c:479
#3  0x00007f33a00addda in xcb_wait_for_event (c=0x55711937c6a0) at xcb_in.c:693
#4  0x00007f3385d8ca49 in QXcbEventReader::run (this=0x557119387660) at qxcbconnection.cpp:1335
#5  0x00007f339a69fb92 in QThreadPrivate::start (arg=0x557119387660) at thread/qthread_unix.cpp:368
#6  0x00007f3398d6d61b in start_thread (arg=0x7f338403e700) at pthread_create.c:465
#7  0x00007f3399a3d91f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f33a20f7940 (LWP 1326)):
---Type <return> to continue, or q <return> to quit---
#0  0x00007f339e7bc7c5 in QV4::PersistentValueStorage::allocate (this=0x55711959f670) at jsruntime/qv4persistent.cpp:189
#1  0x00007f339e9355fb in QQmlListModel::get (this=0x55711cc46e10, index=2184) at types/qqmllistmodel.cpp:2295
#2  0x00007f339e93d5d0 in QQmlListModel::qt_static_metacall (_o=_o@entry=0x55711cc46e10, _c=_c@entry=QMetaObject::InvokeMetaMethod, 
    _id=_id@entry=5, _a=_a@entry=0x7ffc2b8559d0) at .moc/moc_qqmllistmodel_p.cpp:129
#3  0x00007f339e93db45 in QQmlListModel::qt_metacall (this=0x55711cc46e10, _c=QMetaObject::InvokeMetaMethod, _id=5, 
    _a=0x7ffc2b8559d0) at .moc/moc_qqmllistmodel_p.cpp:208
#4  0x00007f339e8b5759 in QQmlObjectOrGadget::metacall (this=0x7ffc2b855d30, type=QMetaObject::InvokeMetaMethod, 
    index=<optimized out>, argv=<optimized out>) at qml/qqmlpropertycache.cpp:1713
#5  0x00007f339e832c19 in CallMethod (object=..., index=<optimized out>, returnType=<optimized out>, argCount=<optimized out>, 
    argTypes=<optimized out>, engine=<optimized out>, callArgs=<optimized out>, callType=<optimized out>)
    at jsruntime/qv4qobjectwrapper.cpp:1086
#6  0x00007f339e83463e in CallPrecise (object=..., data=..., engine=engine@entry=0x557119592730, 
    callArgs=callArgs@entry=0x7f33791a0650, callType=callType@entry=QMetaObject::InvokeMetaMethod)
    at jsruntime/qv4qobjectwrapper.cpp:1348
#7  0x00007f339e835329 in QV4::QObjectMethod::callInternal (this=<optimized out>, callData=0x7f33791a0650, scope=...)
    at jsruntime/qv4qobjectwrapper.cpp:1842
---Type <return> to continue, or q <return> to quit---
#8  0x00007f339e84e3fd in QV4::Object::call (d=0x7f33791a0650, scope=..., this=<optimized out>) at jsruntime/qv4object_p.h:372
#9  QV4::Runtime::method_callProperty (engine=0x557119592730, nameIndex=<optimized out>, callData=0x7f33791a0650)
    at jsruntime/qv4runtime.cpp:1104
#10 0x00007f32cf323183 in ?? ()
#11 0x000055711d7fb4a0 in ?? ()
#12 0xf02ed8d3ae10c300 in ?? ()
#13 0x0000000000000000 in ?? ()

(gdb) quit