simple app with qml failed with SEGFAULT with QSG_RENDER_LOOP=threaded

 root@b2qt-intel-corei7-64:/opt/bug1# gdb ./bug1 
 GNU gdb (GDB) 8.2.1
 Copyright (C) 2018 Free Software Foundation, Inc.
 License GPLv3+: GNU GPL version 3 or later <[http://gnu.org/licenses/gpl.html]>
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.
 Type "show copying" and "show warranty" for details.
 This GDB was configured as "x86_64-poky-linux".
 Type "show configuration" for configuration details.
 For bug reporting instructions, please see:
 <[http://www.gnu.org/software/gdb/bugs/]>.
 Find the GDB manual and other documentation resources online at:
 <[http://www.gnu.org/software/gdb/documentation/]>.

For help, type "help".
 Type "apropos word" to search for commands related to "word"...
 Reading symbols from ./bug1...done.
 (gdb) run 
 Starting program: /opt/bug1/bug1 
 [Thread debugging using libthread_db enabled]
 Using host libthread_db library "/lib/libthread_db.so.1".
 QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
 [New Thread 0x7ffff358a700 (LWP 3921)]
 [New Thread 0x7ffff184a700 (LWP 3925)]
 [New Thread 0x7fffebfff700 (LWP 3926)]

Thread 1 "bug1" received signal SIGSEGV, Segmentation fault.
 0x000055555586c930 in ?? ()
 (gdb) bt
 #0 0x000055555586c930 in ?? ()
 #1 0x00007ffff3bc050f in ?? () from /usr/lib/dri/i965_dri.so
 #2 0x00007ffff3bc0590 in ?? () from /usr/lib/dri/i965_dri.so
 #3 0x00007ffff45769fb in ?? () from /usr/lib/libEGL.so.1
 #4 0x00007ffff45653aa in eglMakeCurrent () from /usr/lib/libEGL.so.1
 #5 0x00007ffff4658c9f in ?? () from /usr/lib/libQt5EglFSDeviceIntegration.so.5
 #6 0x00007ffff7b17e07 in QOpenGLContext::doneCurrent() () from /usr/lib/libQt5Gui.so.5
 #7 0x00007ffff7ae6a5a in QOffscreenSurface::~QOffscreenSurface() () from /usr/lib/libQt5Gui.so.5
 #8 0x00007ffff7ae6a79 in QOffscreenSurface::~QOffscreenSurface() () from /usr/lib/libQt5Gui.so.5
 #9 0x00007ffff05e53e4 in ?? () from /usr/lib/libQt5QuickShapes.so.5
 #10 0x00007ffff05ea2c5 in ?? () from /usr/lib/libQt5QuickShapes.so.5
 #11 0x00007ffff05e107d in ?? () from /usr/lib/libQt5QuickShapes.so.5
 #12 0x00007ffff05e12c0 in QQuickShape::updatePolish() () from /usr/lib/libQt5QuickShapes.so.5
 #13 0x00007ffff28cd493 in QQuickWindowPrivate::polishItems() () from /usr/lib/libQt5Quick.so.5
 #14 0x00007ffff2873d66 in ?? () from /usr/lib/libQt5Quick.so.5
 #15 0x00007ffff2874f65 in ?? () from /usr/lib/libQt5Quick.so.5
 #16 0x00007ffff2875803 in ?? () from /usr/lib/libQt5Quick.so.5
 #17 0x00007ffff7ae5c25 in QWindow::event(QEvent*) () from /usr/lib/libQt5Gui.so.5
 #18 0x00007ffff28d7ffb in QQuickWindow::event(QEvent*) () from /usr/lib/libQt5Quick.so.5
 #19 0x00007ffff728ff20 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
 #20 0x00007ffff7adbb23 in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () from /usr/lib/libQt5Gui.so.5
 #21 0x00007ffff7adbdbd in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/libQt5Gui.so.5
 #22 0x00007ffff7ab7ecb in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Gui.so.5
 #23 0x00007ffff7ab8140 in QWindowSystemInterface::flushWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Gui.so.5
 #24 0x00007ffff460253a in QEglFSWindow::setVisible(bool) () from /usr/lib/libQt5EglFSDeviceIntegration.so.5
 #25 0x00007ffff7ae5833 in QWindowPrivate::setVisible(bool) () from /usr/lib/libQt5Gui.so.5
 #26 0x00007ffff29840a0 in QQuickWindowQmlImpl::setWindowVisibility() () from /usr/lib/libQt5Quick.so.5
 #27 0x00007ffff298453b in QQuickWindowQmlImpl::componentComplete() () from /usr/lib/libQt5Quick.so.5
 #28 0x00007ffff7849c2d in QQmlObjectCreator::finalize(QQmlInstantiationInterrupt&) () from /usr/lib/libQt5Qml.so.5
 #29 0x00007ffff77d3641 in QQmlComponentPrivate::complete(QQmlEnginePrivate*, QQmlComponentPrivate::ConstructionState*) () from /usr/lib/libQt5Qml.so.5
 #30 0x00007ffff77d3752 in QQmlComponentPrivate::completeCreate() () from /usr/lib/libQt5Qml.so.5
 #31 0x00007ffff77d30d9 in QQmlComponent::create(QQmlContext*) () from /usr/lib/libQt5Qml.so.5
 #32 0x00007ffff783e88e in QQmlApplicationEnginePrivate::finishLoad(QQmlComponent*) () from /usr/lib/libQt5Qml.so.5
 #33 0x00007ffff783eb6e in QQmlApplicationEnginePrivate::startLoad(QUrl const&, QByteArray const&, bool) () from /usr/lib/libQt5Qml.so.5
 #34 0x00007ffff783ebad in QQmlApplicationEngine::load(QUrl const&) () from /usr/lib/libQt5Qml.so.5
 #35 0x000055555555644a in main (argc=<optimized out>, argv=<optimized out>) at ../main.cpp:24
 (gdb)

root@b2qt-intel-corei7-64:/opt/bug1# qtdiag
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
Unable to query physical screen size, defaulting to 100 dpi.
To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).
Qt 5.14.0 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 8.3.0) on "eglfs" 
OS: Boot to Qt for Embedded Linux 2.7.1 (warrior) [linux version 4.19.40-intel-pk-standard]

Architecture: x86_64; features: SSE2 SSE3 SSSE3 SSE4.1 SSE4.2 AVX AVX2

Environment:
  QSG_RENDER_LOOP="threaded"

Features: QT_NO_EXCEPTIONS QT_NO_SESSIONMANAGER

Library info:
  PrefixPath: /usr
  DocumentationPath: /usr/share/doc
  HeadersPath: /usr/include/qt5
  LibrariesPath: /usr/lib
  LibraryExecutablesPath: /usr/lib/libexec
  BinariesPath: /usr/bin
  PluginsPath: /usr/lib/plugins
  ImportsPath: /usr/lib/imports
  Qml2ImportsPath: /usr/lib/qml
  ArchDataPath: /usr/lib
  DataPath: /usr/share
  TranslationsPath: /usr/share/translations
  ExamplesPath: /usr/share/examples
  TestsPath: /usr/share/tests
  SettingsPath: /etc

Standard paths [*...* denote writable entry]:
  DesktopLocation: "Desktop" */home/root/Desktop*
  DocumentsLocation: "Documents" */home/root/Documents*
  FontsLocation: "Fonts" */home/root/.local/share/fonts* /home/root/.fonts /usr/local/share/fonts /usr/share/fonts
  ApplicationsLocation: "Applications" */home/root/.local/share/applications* /usr/local/share/applications /usr/share/applications
  MusicLocation: "Music" */home/root/Music*
  MoviesLocation: "Movies" */home/root/Videos*
  PicturesLocation: "Pictures" */home/root/Pictures*
  TempLocation: "Temporary Directory" */tmp*
  HomeLocation: "Home" */home/root*
  AppLocalDataLocation: "Application Data" */home/root/.local/share/QtProject/qtdiag* /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag
  CacheLocation: "Cache" */home/root/.cache/QtProject/qtdiag*
  GenericDataLocation: "Shared Data" */home/root/.local/share* /usr/local/share /usr/share
  RuntimeLocation: "Runtime" */tmp/runtime-root*
  ConfigLocation: "Configuration" */home/root/.config* /etc/xdg
  DownloadLocation: "Download" */home/root/Downloads*
  GenericCacheLocation: "Shared Cache" */home/root/.cache*
  GenericConfigLocation: "Shared Configuration" */home/root/.config* /etc/xdg
  AppDataLocation: "Application Data" */home/root/.local/share/QtProject/qtdiag* /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag
  AppConfigLocation: "Application Configuration" */home/root/.config/QtProject/qtdiag* /etc/xdg/QtProject/qtdiag

File selectors (increasing order of precedence):
  C unix linux b2qt

Network:
  Using "OpenSSL 1.1.1b  26 Feb 2019", version: 0x1010102f

Platform capabilities: ThreadedPixmaps OpenGL ThreadedOpenGL NonFullScreenWindows NativeWidgets RasterGLSurface

Style hints:
  mouseDoubleClickInterval: 400
  mousePressAndHoldInterval: 800
  startDragDistance: 10
  startDragTime: 500
  startDragVelocity: 0
  keyboardInputInterval: 400
  keyboardAutoRepeatRate: 30
  cursorFlashTime: 1000
  showIsFullScreen: 0
  showIsMaximized: 0
  passwordMaskDelay: 0
  passwordMaskCharacter: U+25CF
  fontSmoothingGamma: 1.7
  useRtlExtensions: 0
  setFocusOnTouchRelease: 0
  tabFocusBehavior: Qt::TabFocusAllControls 
  singleClickActivation: 0

Additional style hints (QPlatformIntegration):
  ReplayMousePressOutsidePopup: 1

Theme:
  Platforms requested : 
            available : snap,flatpak,xdgdesktopportal
  Styles requested    : 
         available    : Windows,Fusion
Fonts:
  General font : "Bitstream Vera Sans" 12
  Fixed font   : "Bitstream Vera Sans" 12
  Title font   : "Bitstream Vera Sans" 12
  Smallest font: "Bitstream Vera Sans" 12

Palette:
  QPalette::WindowText: #ff000000
  QPalette::Button: #ffefefef
  QPalette::Light: #ffffffff
  QPalette::Midlight: #ffcbcbcb
  QPalette::Dark: #ff9f9f9f
  QPalette::Mid: #ffb8b8b8
  QPalette::Text: #ff000000
  QPalette::BrightText: #ffffffff
  QPalette::ButtonText: #ff000000
  QPalette::Base: #ffffffff
  QPalette::Window: #ffefefef
  QPalette::Shadow: #ff767676
  QPalette::Highlight: #ff308cc6
  QPalette::HighlightedText: #ffffffff
  QPalette::Link: #ff0000ff
  QPalette::LinkVisited: #ffff00ff
  QPalette::AlternateBase: #fff7f7f7
  QPalette::NoRole: #ff000000
  QPalette::ToolTipBase: #ffffffdc
  QPalette::ToolTipText: #ff000000
  QPalette::PlaceholderText: #80000000

Screens: 3, High DPI scaling: inactive
# 0 "DP1" Depth: 32 Primary: yes
  Manufacturer: GEC
  Model: Onlap1503-
  Serial number: 8888-
  Geometry: 1920x1080+0+0 Available: 1920x1080+0+0
  Virtual geometry: 5760x1080+0+0 Available: 5760x1080+0+0
  3 virtual siblings
  Physical size: 350x200 mm  Refresh: 60 Hz Power state: 0
  Physical DPI: 139.337,137.16 Logical DPI: 139.337,137.16 Subpixel_None
  DevicePixelRatio: 1 Pixel density: 1
  Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

# 1 "DP3" Depth: 32 Primary: no
  Manufacturer: GEC
  Model: Onlap1303-
  Serial number: 8888-
  Geometry: 1920x1080+1920+0 Available: 1920x1080+1920+0
  Virtual geometry: 5760x1080+0+0 Available: 5760x1080+0+0
  3 virtual siblings
  Physical size: 300x170 mm  Refresh: 60 Hz Power state: 0
  Physical DPI: 162.56,161.365 Logical DPI: 162.56,161.365 Subpixel_None
  DevicePixelRatio: 1 Pixel density: 1
  Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

# 2 "DP4" Depth: 32 Primary: no
  Manufacturer: Acer Technologies
  Model: Acer H6517ST-
  Serial number: JLA110015910-
  Geometry: 1920x1080+3840+0 Available: 1920x1080+3840+0
  Virtual geometry: 5760x1080+0+0 Available: 5760x1080+0+0
  3 virtual siblings
  Physical size: 487.68x274.32 mm  Refresh: 60 Hz Power state: 0
  Physical DPI: 100,100 Logical DPI: 100,100 Subpixel_None
  DevicePixelRatio: 1 Pixel density: 1
  Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

Touch devices: 1
  TouchScreen "ILITEK Multi-Touch-V5100", max 1 touch points, capabilities: Position Area


LibGLES Vendor: Intel Open Source Technology Center
Renderer: Mesa DRI Intel(R) Iris Plus Graphics 650 (Kaby Lake GT3e) 
Version: OpenGL ES 3.2 Mesa 19.0.1
Shading language: OpenGL ES GLSL ES 3.20
Format: Version: 3.2 Profile: 0 Swap behavior: 0 Buffer size (RGB): 8,8,8