Here's the crash with GDK_SYNCHRONIZE=1. It appears to be graphical. And I have a theory this maybe only happens on machines that default to hi-DPI (scale 200%) in the live session...
#6 0x00007fffef656c8d in _XError () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#7 0x00007fffef653bb7 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#8 0x00007fffef653c75 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#9 0x00007fffef654b88 in _XReply () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#10 0x00007fffef65057d in XSync () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#11 0x00007fffef65061b in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#12 0x00007fffef65760f in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#13 0x00007fffef40d7b7 in XShmAttach ()
from /usr/lib/x86_64-linux-gnu/libXext.so.6
#14 0x00007fffef18b82b in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#15 0x00007fffef18c05e in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#16 0x00007fffef189c81 in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#17 0x00007fffef1868e8 in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#18 0x00007fffef16a585 in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
---Type <return> to continue, or q <return> to quit---
#19 0x00007fffef16a78c in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#20 0x00007fffef16ae28 in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#21 0x00007fffef10e021 in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#22 0x00007fffef157efc in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#23 0x00007fffef11657e in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#24 0x00007fffef10fb39 in ?? () from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#25 0x00007fffef108a55 in cairo_fill ()
from /usr/lib/x86_64-linux-gnu/libcairo.so.2
#26 0x00007fffc2e66240 in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#27 0x00007fffc1fd1e61 in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#28 0x00007fffc2051a3b in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#29 0x00007fffc1fdbbd1 in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#30 0x00007fffc1fe1897 in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#31 0x00007fffc1f4879f in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#32 0x00007fffc1ccabde in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#33 0x00007fffc1daeed2 in ?? ()
---Type <return> to continue, or q <return> to quit---
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#34 0x00007fffc1cc67ab in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#35 0x00007fffc1cc7095 in ?? ()
from /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37
#36 0x00007fffc1005903 in WTF::RunLoop::performWork() ()
from /usr/lib/x86_64-linux-gnu/libjavascriptcoregtk-4.0.so.18
#37 0x00007fffc102e959 in ?? ()
from /usr/lib/x86_64-linux-gnu/libjavascriptcoregtk-4.0.so.18
#38 0x00007ffff4b9e0f5 in g_main_context_dispatch ()
from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#39 0x00007ffff4b9e4c0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#40 0x00007ffff4b9e7d2 in g_main_loop_run ()
from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#41 0x00007fffec971385 in gtk_main ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#42 0x00007ffff494fdae in ffi_call_unix64 ()
from /usr/lib/x86_64-linux-gnu/libffi.so.6
#43 0x00007ffff494f71f in ffi_call ()
from /usr/lib/x86_64-linux-gnu/libffi.so.6
#44 0x00007ffff531bdda in ?? ()
from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-x86_64-linux-gnu.so
#45 0x00007ffff531d9b8 in ?? ()
---Type <return> to continue, or q <return> to quit---
from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-x86_64-linux-gnu.so
#46 0x000000000045a0e3 in _PyObject_FastCallDict ()
#47 0x000000000054fd37 in ?? ()
#48 0x00000000005546cf in _PyEval_EvalFrameDefault ()
Here's the crash with GDK_SYNCHRONIZE=1. It appears to be graphical. And I have a theory this maybe only happens on machines that default to hi-DPI (scale 200%) in the live session...
#6 0x00007fffef656c8d in _XError () from /usr/lib/ x86_64- linux-gnu/ libX11. so.6 x86_64- linux-gnu/ libX11. so.6 x86_64- linux-gnu/ libX11. so.6 x86_64- linux-gnu/ libX11. so.6 x86_64- linux-gnu/ libX11. so.6 x86_64- linux-gnu/ libX11. so.6 x86_64- linux-gnu/ libX11. so.6 x86_64- linux-gnu/ libXext. so.6 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libcairo. so.2 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 x86_64- linux-gnu/ libwebkit2gtk- 4.0.so. 37 :performWork( ) () x86_64- linux-gnu/ libjavascriptco regtk-4. 0.so.18 x86_64- linux-gnu/ libjavascriptco regtk-4. 0.so.18 context_ dispatch () x86_64- linux-gnu/ libglib- 2.0.so. 0 x86_64- linux-gnu/ libglib- 2.0.so. 0 x86_64- linux-gnu/ libglib- 2.0.so. 0 x86_64- linux-gnu/ libgtk- 3.so.0 x86_64- linux-gnu/ libffi. so.6 x86_64- linux-gnu/ libffi. so.6 python3/ dist-packages/ gi/_gi. cpython- 36m-x86_ 64-linux- gnu.so python3/ dist-packages/ gi/_gi. cpython- 36m-x86_ 64-linux- gnu.so FastCallDict () EvalFrameDefaul t ()
#7 0x00007fffef653bb7 in ?? () from /usr/lib/
#8 0x00007fffef653c75 in ?? () from /usr/lib/
#9 0x00007fffef654b88 in _XReply () from /usr/lib/
#10 0x00007fffef65057d in XSync () from /usr/lib/
#11 0x00007fffef65061b in ?? () from /usr/lib/
#12 0x00007fffef65760f in ?? () from /usr/lib/
#13 0x00007fffef40d7b7 in XShmAttach ()
from /usr/lib/
#14 0x00007fffef18b82b in ?? () from /usr/lib/
#15 0x00007fffef18c05e in ?? () from /usr/lib/
#16 0x00007fffef189c81 in ?? () from /usr/lib/
#17 0x00007fffef1868e8 in ?? () from /usr/lib/
#18 0x00007fffef16a585 in ?? () from /usr/lib/
---Type <return> to continue, or q <return> to quit---
#19 0x00007fffef16a78c in ?? () from /usr/lib/
#20 0x00007fffef16ae28 in ?? () from /usr/lib/
#21 0x00007fffef10e021 in ?? () from /usr/lib/
#22 0x00007fffef157efc in ?? () from /usr/lib/
#23 0x00007fffef11657e in ?? () from /usr/lib/
#24 0x00007fffef10fb39 in ?? () from /usr/lib/
#25 0x00007fffef108a55 in cairo_fill ()
from /usr/lib/
#26 0x00007fffc2e66240 in ?? ()
from /usr/lib/
#27 0x00007fffc1fd1e61 in ?? ()
from /usr/lib/
#28 0x00007fffc2051a3b in ?? ()
from /usr/lib/
#29 0x00007fffc1fdbbd1 in ?? ()
from /usr/lib/
#30 0x00007fffc1fe1897 in ?? ()
from /usr/lib/
#31 0x00007fffc1f4879f in ?? ()
from /usr/lib/
#32 0x00007fffc1ccabde in ?? ()
from /usr/lib/
#33 0x00007fffc1daeed2 in ?? ()
---Type <return> to continue, or q <return> to quit---
from /usr/lib/
#34 0x00007fffc1cc67ab in ?? ()
from /usr/lib/
#35 0x00007fffc1cc7095 in ?? ()
from /usr/lib/
#36 0x00007fffc1005903 in WTF::RunLoop:
from /usr/lib/
#37 0x00007fffc102e959 in ?? ()
from /usr/lib/
#38 0x00007ffff4b9e0f5 in g_main_
from /usr/lib/
#39 0x00007ffff4b9e4c0 in ?? () from /usr/lib/
#40 0x00007ffff4b9e7d2 in g_main_loop_run ()
from /usr/lib/
#41 0x00007fffec971385 in gtk_main ()
from /usr/lib/
#42 0x00007ffff494fdae in ffi_call_unix64 ()
from /usr/lib/
#43 0x00007ffff494f71f in ffi_call ()
from /usr/lib/
#44 0x00007ffff531bdda in ?? ()
from /usr/lib/
#45 0x00007ffff531d9b8 in ?? ()
---Type <return> to continue, or q <return> to quit---
from /usr/lib/
#46 0x000000000045a0e3 in _PyObject_
#47 0x000000000054fd37 in ?? ()
#48 0x00000000005546cf in _PyEval_