seg fault when setSocketDescriptor on tcp socket

callstack:

#0 tcache_get (tc_idx=1) at malloc.c:2943
#1 _GI__libc_malloc (bytes=40) at malloc.c:3050
#2 0x00007ffff69071a8 in operator new(unsigned long) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3 0x00007ffff742515e in QHostAddress::QHostAddress() () from /home/shiy/dist/lib/libQt5Network.so.5
#4 0x00007ffff743ecd2 in QAbstractSocketEnginePrivate::QAbstractSocketEnginePrivate() () from /home/shiy/dist/lib/libQt5Network.so.5
#5 0x00007ffff74515ef in QNativeSocketEngine::QNativeSocketEngine(QObject*) () from /home/shiy/dist/lib/libQt5Network.so.5
#6 0x00007ffff743f208 in QAbstractSocketEngine::createSocketEngine(long long, QObject*) () from /home/shiy/dist/lib/libQt5Network.so.5
#7 0x00007ffff74407fa in QAbstractSocket::setSocketDescriptor(long long, QAbstractSocket::SocketState, QFlags<QIODevice::OpenModeFlag>) () from /home/shiy/dist/lib/libQt5Network.so.5
#8 0x000055555568e550 in Worker::newSocket (this=0x555555951540, socket=11) at ../../../server/Swiftly/Swiftly/Worker.cpp:189
#9 0x000055555569e99e in Worker::qt_static_metacall (_o=0x555555951540, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0x7fffe0004df0) at moc_Worker.cpp:82
#10 0x00007ffff6e93d61 in QObject::event(QEvent*) () from /home/shiy/dist/lib/libQt5Core.so.5
#11 0x00007ffff6e67f43 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /home/shiy/dist/lib/libQt5Core.so.5
#12 0x00007ffff6e6a96b in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /home/shiy/dist/lib/libQt5Core.so.5
#13 0x00007ffff6ebca13 in postEventSourceDispatch(_GSource*, int (void*), void*) () from /home/shiy/dist/lib/libQt5Core.so.5
#14 0x00007ffff2c90387 in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#15 0x00007ffff2c905c0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#16 0x00007ffff2c9064c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#17 0x00007ffff6ebc07f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /home/shiy/dist/lib/libQt5Core.so.5
#18 0x00007ffff6e668ba in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /home/shiy/dist/lib/libQt5Core.so.5
#19 0x00007ffff6ca0aac in QThread::exec() () from /home/shiy/dist/lib/libQt5Core.so.5
#20 0x000055555568f819 in Worker::run (this=0x555555951540) at ../../../server/Swiftly/Swiftly/Worker.cpp:374
#21 0x00007ffff6cab5a4 in QThreadPrivate::start(void*) () from /home/shiy/dist/lib/libQt5Core.so.5
#22 0x00007ffff60536db in start_thread (arg=0x7fffee81f700) at pthread_create.c:463
#23 0x00007ffff638c88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

when performing setDescriptor on a socket, I saw the above crash. the input to the setSocketDescriptor function was 11,