[ Impact ]
color-picker is completely unusable as it results in a segfault as soon the user tries to execute it.
The trace from the coredump shows that QObject is passed as NULL to doActivate() in QT libraries.
[ Test Plan ]
* Execute the command "color-picker", which will immediately result in a segfault.
[ Where problems could occur ]
The patch uses the "this" pointer to access the object instead of the "qApp". The QT docs says "The global qApp pointer refers to the application object". So qApp pointer should not have caused the problem unless the source has missed something in the way its using QT calls.
The patch has been forwarded upstream, either they can accept the patch or they will now find out why qApp pointer is invalid if LTO is enabled.
If there is any problem due to this patch, then at the worst case the stylesheet will not work and the window will have the default style.
[ Other Info ]
* All versions from Jammy are affected by this.
* The full trace from the coredump is given at the upstream issue.
[ Original Bug Description ]
$ color-picker
Segmentation fault (core dumped)
$ ldd /usr/bin/color-picker
linux-vdso.so.1 (0x00007ffe6f7a5000)
libQt5Widgets.so.5 => /lib/x86_64-linux-gnu/libQt5Widgets.so.5 (0x00007faf9c400000)
libQt5Gui.so.5 => /lib/x86_64-linux-gnu/libQt5Gui.so.5 (0x00007faf9bc00000)
libQt5Core.so.5 => /lib/x86_64-linux-gnu/libQt5Core.so.5 (0x00007faf9b600000)
libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007faf9b200000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007faf9cc34000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007faf9ae00000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007faf9cb4b000)
libGL.so.1 => /lib/x86_64-linux-gnu/libGL.so.1 (0x00007faf9cac4000)
libpng16.so.16 => /lib/x86_64-linux-gnu/libpng16.so.16 (0x00007faf9c3c5000)
libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007faf9c3a9000)
libharfbuzz.so.0 => /lib/x86_64-linux-gnu/libharfbuzz.so.0 (0x00007faf9b531000)
libmd4c.so.0 => /lib/x86_64-linux-gnu/libmd4c.so.0 (0x00007faf9c397000)
libdouble-conversion.so.3 => /lib/x86_64-linux-gnu/libdouble-conversion.so.3 (0x00007faf9c382000)
libicui18n.so.70 => /lib/x86_64-linux-gnu/libicui18n.so.70 (0x00007faf9aa00000)
libicuuc.so.70 => /lib/x86_64-linux-gnu/libicuuc.so.70 (0x00007faf9a805000)
libpcre2-16.so.0 => /lib/x86_64-linux-gnu/libpcre2-16.so.0 (0x00007faf9c2f8000)
libzstd.so.1 => /lib/x86_64-linux-gnu/libzstd.so.1 (0x00007faf9b462000)
libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007faf9b0c6000)
/lib64/ld-linux-x86-64.so.2 (0x00007faf9ccf6000)
libGLdispatch.so.0 => /lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007faf9ad48000)
libGLX.so.0 => /lib/x86_64-linux-gnu/libGLX.so.0 (0x00007faf9bbcc000)
libfreetype.so.6 => /lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007faf9a73d000)
libgraphite2.so.3 => /lib/x86_64-linux-gnu/libgraphite2.so.3 (0x00007faf9bba5000)
libicudata.so.70 => /lib/x86_64-linux-gnu/libicudata.so.70 (0x00007faf98a00000)
libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007faf9b050000)
libX11.so.6 => /lib/x86_64-linux-gnu/libX11.so.6 (0x00007faf988c0000)
libbrotlidec.so.1 => /lib/x86_64-linux-gnu/libbrotlidec.so.1 (0x00007faf9c2e6000)
libxcb.so.1 => /lib/x86_64-linux-gnu/libxcb.so.1 (0x00007faf9bb7b000)
libbrotlicommon.so.1 => /lib/x86_64-linux-gnu/libbrotlicommon.so.1 (0x00007faf9b43f000)
libXau.so.6 => /lib/x86_64-linux-gnu/libXau.so.6 (0x00007faf9c2de000)
libXdmcp.so.6 => /lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007faf9bb73000)
libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007faf9b038000)
libmd.so.0 => /lib/x86_64-linux-gnu/libmd.so.0 (0x00007faf9bb66000)
I have tested and can reproduce the issue on Jammy, Mantic, Lunar and Noble. If LTO is disabled then the application runs without segfault,
I have opened an upstream issue with the full trace from the coredump at https:/