Linux: Crash in Qt and wxPython examples during browser creation due to x11 FindChild() failing

[cztomczak]

This needs to be patched during next CEF Python release (internal patch or merged PR upstream).

Reported in upstream CEF tracker:
https://bitbucket.org/chromiumembedded/cef/issues/2490/x11-findchild-fails-during-a-call-to

Reported problem on the CEF Forum:
https://magpcss.org/ceforum/viewtopic.php?f=6&t=16203

Reproducible so far with the following examples:

• PyQt4
• PySide
• wxPython 4 - reported here

The PyQt5 example works fine (Python 3.6, Ubuntu 14.04 same machine).

Stack trace for qt.py pyqt4 example running on Python 2.7.6 and Ubuntu 14.04:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff1d9e0bf in FindChild () at ../../cef/libcef/browser/native/window_x11.cc:44
44	../../cef/libcef/browser/native/window_x11.cc: No such file or directory.
(gdb) bt
#0  0x00007ffff1d9e0bf in FindChild () at ../../cef/libcef/browser/native/window_x11.cc:44
#1  Show () at ../../cef/libcef/browser/native/window_x11.cc:178
#2  0x00007ffff1d9aa57 in CreateHostWindow ()
    at ../../cef/libcef/browser/native/browser_platform_delegate_native_linux.cc:89
#3  0x00007ffff1cb5879 in CreateHostWindow () at ../../cef/libcef/browser/browser_host_impl.cc:3159
#4  CreateInternal () at ../../cef/libcef/browser/browser_host_impl.cc:418
#5  0x00007ffff1cb436f in Create () at ../../cef/libcef/browser/browser_host_impl.cc:359
#6  0x00007ffff1cb3b3d in CreateBrowserSync () at ../../cef/libcef/browser/browser_host_impl.cc:275
#7  0x00007ffff046be21 in cef_browser_host_create_browser_sync ()
    at ../../cef/libcef_dll/cpptoc/browser_host_cpptoc.cc:94
#8  0x00007fffe743ad58 in CefBrowserHost::CreateBrowserSync(CefWindowInfo const&, scoped_refptr<CefClient>, CefStringBase<CefStringTraitsUTF16> const&, CefStructBase<CefBrowserSettingsTraits> const&, scoped_refptr<CefRequestContext>) ()
   from /usr/local/lib/python2.7/dist-packages/cefpython3/cefpython_py27.so
#9  0x00007fffffffcb70 in ?? ()
#10 0x0000000001067c50 in ?? ()
#11 0x00000000010406b0 in ?? ()
#12 0x00000000010406b0 in ?? ()
#13 0x00007fffe76f2fc0 in __pyx_v_14cefpython_py27_g_external_message_pump ()
   from /usr/local/lib/python2.7/dist-packages/cefpython3/cefpython_py27.so
#14 0x00000000009420a0 in ?? ()
#15 0x00007fffffffcd60 in ?? ()
#16 0x00007fffe24a4fc8 in ?? ()
#17 0x00007ffff7e7f8f0 in ?? ()
#18 0x0000000000000000 in ?? ()

Stack for qt.py pyside is the same.

Corresponding CEF source codes for the stack trace:
0. https://github.com/chromiumembedded/cef/blob/3359/libcef/browser/native/window_x11.cc#L44

1. https://github.com/chromiumembedded/cef/blob/3359/libcef/browser/native/window_x11.cc#L178
2. https://github.com/chromiumembedded/cef/blob/3359/libcef/browser/native/browser_platform_delegate_native_linux.cc#L89
3. https://github.com/chromiumembedded/cef/blob/3359/libcef/browser/browser_host_impl.cc#L3159
4. https://github.com/chromiumembedded/cef/blob/3359/libcef/browser/browser_host_impl.cc#L418
5. https://github.com/chromiumembedded/cef/blob/3359/libcef/browser/browser_host_impl.cc#L359
6. https://github.com/chromiumembedded/cef/blob/3359/libcef/browser/browser_host_impl.cc#L275

[cztomczak]

PyQt4 and PySide examples disabled from auto running in commit cb9628b.

[cztomczak]

I've provided a patch that fixes the issue in upstream CEF. However this still needs testing with PyQt4 and PySide to see if that resolves the issue completely.

[dee42]

This is biting me with wxPython 4 with GTK 3. Is there any way to work around the issue with cefpython 66? If not, when are you expecting the next cefpython release?