Gnome session from git master branch exits randomly.
Downgrading gnome-settings-daemon/gnome-session to 3.22 stops this.

coredumpctl captured the following.

coredumpctl gdb 16777
           PID: 16777 (gnome-session-f)
           UID: 1000 (hussam)
           GID: 100 (users)
        Signal: 11 (SEGV)
     Timestamp: Sun 2017-01-01 14:33:53 EET (8min ago)
  Command Line: /usr/lib/gnome-session/gnome-session-failed --allow-logout
    Executable: /usr/lib/gnome-session/gnome-session-failed
 Control Group: /user.slice/user-1000.slice/session-c9.scope
          Unit: session-c9.scope
         Slice: user-1000.slice
       Session: c9
     Owner UID: 1000 (hussam)
       Boot ID: d50a378e7c1e4d069242f06d3afb841e
    Machine ID: efb490e643e2436d9d1138df1745a008
      Hostname: hades
       Storage: /var/lib/systemd/coredump/core.gnome-session-f.1000.d50a378e7c1e4d069242f06d3afb841e.16777.1483274033000000000000.lz4
       Message: Process 16777 (gnome-session-f) of user 1000 dumped core.
                
                Stack trace of thread 16777:
                #0  0x00007fa779785e79 _gtk_style_provider_private_get_settings (libgtk-3.so.0)
                #1  0x00007fa779621a58 gtk_css_value_initial_compute (libgtk-3.so.0)
                #2  0x00007fa779636ad4 gtk_css_static_style_compute_value (libgtk-3.so.0)
                #3  0x00007fa779622d7c _gtk_css_lookup_resolve (libgtk-3.so.0)
                #4  0x00007fa7796369fc gtk_css_static_style_new_compute (libgtk-3.so.0)
                #5  0x00007fa779636a55 gtk_css_static_style_get_default (libgtk-3.so.0)
                #6  0x00007fa7796236e2 gtk_css_node_init (libgtk-3.so.0)
                #7  0x00007fa778f8d207 g_type_create_instance (libgobject-2.0.so.0)
                #8  0x00007fa778f6e57b g_object_new_internal (libgobject-2.0.so.0)
                #9  0x00007fa778f6ffbd g_object_newv (libgobject-2.0.so.0)
                #10 0x00007fa778f70754 g_object_new (libgobject-2.0.so.0)
                #11 0x00007fa77963ef1a gtk_css_widget_node_new (libgtk-3.so.0)
                #12 0x00007fa77981ce27 gtk_widget_init (libgtk-3.so.0)
                #13 0x00007fa778f8d207 g_type_create_instance (libgobject-2.0.so.0)
                #14 0x00007fa778f6e57b g_object_new_internal (libgobject-2.0.so.0)
                #15 0x00007fa778f6ffbd g_object_newv (libgobject-2.0.so.0)
                #16 0x00007fa778f70754 g_object_new (libgobject-2.0.so.0)
                #17 0x0000000000401e25 n/a (gnome-session-failed)
                #18 0x00007fa7788c8291 __libc_start_main (libc.so.6)
                #19 0x000000000040222a n/a (gnome-session-failed)

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Reading symbols from /usr/lib/gnome-session/gnome-session-failed...done.

warning: core file may not match specified executable file.
[New LWP 16777]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
Core was generated by `/usr/lib/gnome-session/gnome-session-failed --allow-logout'.
Program terminated with signal SIGSEGV, Segmentation fault.

+ Trace 237028