Update: I have found a way to cause this bug 100% repeatable. Open a terminal window and type firefox -new-instance and immediate segfault. The resulting errors:
xfce4-session[11891]: segfault at ffffffff00000000 ip 00007fb430233f7f sp 00007fffb89662f0 error 5 in libglib-2.0.so.0.3600.0[7fb4301d0000+f9000]
xfce4-session[9120]: segfault at ffffffff00000000 ip 00007fb98e8c3f7f sp 00007fffa3dd2c50 error 5 in libglib-2.0.so.0.3600.0[7fb98e860000+f9000]
Update: I have found a way to cause this bug 100% repeatable. Open a terminal window and type firefox -new-instance and immediate segfault. The resulting errors:
xfce4-session[ 11891]: segfault at ffffffff00000000 ip 00007fb430233f7f sp 00007fffb89662f0 error 5 in libglib- 2.0.so. 0.3600. 0[7fb4301d0000+ f9000]
xfce4-session[ 9120]: segfault at ffffffff00000000 ip 00007fb98e8c3f7f sp 00007fffa3dd2c50 error 5 in libglib- 2.0.so. 0.3600. 0[7fb98e860000+ f9000]