Some qt3d demo applications crash with QPA Wayland-EGL

The following Qt3d demo applications crash with QPA Wayland(-EGL).

SoC: TI AM57xx
Linux: Kernel 4.14
Qt: 5.9.7

It looks like the problem is that wl_egl_window_resize() is called with invalid egl_window.

Here is a trace of good example: scene3d:

root@am57xx-evm:~# /usr/share/qt5/examples/qt3d/scene3d/scene3d
Using Wayland-EGL
wlpvr: PVR Services Initialised
QWaylandEglWindow::QWaylandEglWindow 0x0
Using the 'xdg-shell-v5' shell integration
QWaylandEglWindow::updateSurface 0x0
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb70b8, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb70b8, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb70b8
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xb70b8
wlpvr: wl_egl_window_destroy: egl_window=0xb70b8
QWaylandEglWindow::updateSurface 0x0
QWaylandEglWindow::updateSurface call wl_egl_window_create
wlpvr: wl_egl_window_resize: egl_window=0xaff009e0, 506x533, 0,0
wlpvr: wl_egl_window_create: egl_window=0xaff009e0, 506x533
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xaff12348, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xaff12348, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xaff12348
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xaff12348
wlpvr: wl_egl_window_destroy: egl_window=0xaff12348
wl_surface.enter received for output with id: 10 screen name: "unknown" screen model: "" 0x34f70
QWaylandEglWindow::QWaylandEglWindow 0x0
^C

wl_egl_window_size() is called at QWaylandEglWindow::updateSurface to set m_waylandEglWindow.

Here is the bad case: qardboard 

root@am57xx-evm:~# /usr/share/qt5/examples/qt3d/qardboard/qardboard
Using Wayland-EGL
wlpvr: PVR Services Initialised
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb150efd0, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb150efd0, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb150efd0
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xb150efd0
wlpvr: wl_egl_window_destroy: egl_window=0xb150efd0
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb15173c8, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb15173c8, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb15173c8
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xb15173c8
wlpvr: wl_egl_window_destroy: egl_window=0xb15173c8
Using the 'xdg-shell-v5' shell integration
QWaylandEglWindow::QWaylandEglWindow 0x0
QWaylandEglWindow::updateSurface 0xb5e412f4
wlpvr: wl_egl_window_get_attached_size: egl_window=0xb5e412f4, -1245645312x-1245646408
wlpvr: wl_egl_window_resize: egl_window=0xb5e412f4, 806x433, 0,0
Segmentation fault (core dumped)

We do know why m_waylandEglWindow was set to 0xb5e412f4 before wl_egl_window_create() is called. And therefore wl_egl_window_resiz() is called with the invalid egl_window and the overall timing is different from the good case.

The same error is also observed for anaglyph-rendering and scene2d

root@am57xx-evm:~# /usr/share/qt5/examples/qt3d/anaglyph-rendering/anaglyph-renering
Using Wayland-EGL
wlpvr: PVR Services Initialised
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb160efd0, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb160efd0, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb160efd0
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xb160efd0
wlpvr: wl_egl_window_destroy: egl_window=0xb160efd0
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb16173c8, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb16173c8, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb16173c8
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xb16173c8
wlpvr: wl_egl_window_destroy: egl_window=0xb16173c8
Using the 'xdg-shell-v5' shell integration
QWaylandEglWindow::QWaylandEglWindow 0x0
QWaylandEglWindow::updateSurface 0xb5ef22f4
wlpvr: wl_egl_window_get_attached_size: egl_window=0xb5ef22f4, -1244920320x-1244921416
wlpvr: wl_egl_window_resize: egl_window=0xb5ef22f4, 1030x801, 0,0
Segmentation fault (core dumped)
root@am57xx-evm:~# /usr/share/qt5/examples/qt3d/scene2d/scene2d
Using Wayland-EGL
wlpvr: PVR Services Initialised
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb160efd0, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb160efd0, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb160efd0
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xb160efd0
wlpvr: wl_egl_window_destroy: egl_window=0xb160efd0
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb16173c8, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb16173c8, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb16173c8
QWaylandGLContext::updateGLFormat: call wl_egl_window_destroy 0xb16173c8
wlpvr: wl_egl_window_destroy: egl_window=0xb16173c8
QWaylandEglWindow::QWaylandEglWindow 0x0
Using the 'xdg-shell-v5' shell integration
Non-blocking swap buffers not supported. Subsurface rendering can be affected.
wlpvr: wl_egl_window_resize: egl_window=0xb1532c78, 1x1, 0,0
wlpvr: wl_egl_window_create: egl_window=0xb1532c78, 1x1
QWaylandGLContext::updateGLFormat: call wl_egl_window_create 0xb1532c78
QWaylandEglWindow::QWaylandEglWindow 0x0
QWaylandEglWindow::updateSurface 0xb5ea32f4
wlpvr: wl_egl_window_get_attached_size: egl_window=0xb5ea32f4, -1245243904x-1245245000
wlpvr: wl_egl_window_resize: egl_window=0xb5ea32f4, 1406x1133, 0,0
Segmentation fault (core dumped)