Process 327 (Xorg) of user 0 dumped core.
                                                  
Stack trace of thread 327:
#0  0x00007f27dcee086b raise (libc.so.6)
#1  0x00007f27dcecb40e abort (libc.so.6)
#2  0x000055f9d481160a OsAbort (Xorg)
#3  0x000055f9d48116ff FatalError (Xorg)
#4  0x000055f9d4947e1e n/a (Xorg)
#5  0x00007f27dcee08f0 __restore_rt (libc.so.6)
#6  0x000055f9d491cf7e miRenderColorToPixel (Xorg)
#7  0x00007f27d624eaf8 n/a (libexa.so)
#8  0x000055f9d491b6af n/a (Xorg)
#9  0x000055f9d48c288a n/a (Xorg)
#10 0x000055f9d47f5ef8 n/a (Xorg)
#11 0x00007f27dcecd06b __libc_start_main (libc.so.6)
#12 0x000055f9d47f621a _start (Xorg)

Stack trace of thread 329:
#0  0x00007f27daf1fffc pthread_cond_wait@@GLIBC_2.3.2 (libpthread.so.0)
#1  0x00007f27d4d8f634 n/a (nouveau_dri.so)
#2  0x00007f27d4d8f328 n/a (nouveau_dri.so)
#3  0x00007f27daf1a075 start_thread (libpthread.so.0)
#4  0x00007f27dcfa253f __clone (libc.so.6)
Process 443 (xfce4-panel) of user 1000 dumped core.

Stack trace of thread 443:
#0  0x00007f9e37fe4820 XScreenCount (libX11.so.6)
#1  0x0000562396cffc3a panel_application_load (xfce4-panel)
#2  0x0000562396cfd68c main (xfce4-panel)
#3  0x00007f9e35c1706b __libc_start_main (libc.so.6)
#4  0x0000562396cfd7da _start (xfce4-panel)