Stack trace of thread 463: #0 0x00007f9ef7ece750 cairo_surface_get_type (libcairo.so.2) #1 0x0000000000413a83 greeter_background_save_xroot (lightdm-gtk-greeter) #2 0x000000000040e248 n/a (lightdm-gtk-greeter) #3 0x00007f9ef765b0e6 n/a (libgobject-2.0.so.0) #4 0x00007f9ef7675fbf g_signal_emit_valist (libgobject-2.0.so.0) #5 0x00007f9ef76766ef g_signal_emit (libgobject-2.0.so.0) #6 0x00007f9ef7124b91 n/a (liblightdm-gobject-1.so.0) #7 0x00007f9ef7124f4d n/a (liblightdm-gobject-1.so.0) #8 0x00007f9ef73828b5 g_main_context_dispatch (libglib-2.0.so.0) #9 0x00007f9ef7382c78 n/a (libglib-2.0.so.0) #10 0x00007f9ef7382f92 g_main_loop_run (libglib-2.0.so.0) #11 0x00007f9ef86aced5 gtk_main (libgtk-3.so.0) #12 0x000000000040c537 main (lightdm-gtk-greeter) #13 0x00007f9ef630c43a __libc_start_main (libc.so.6) #14 0x000000000040d21a _start (lightdm-gtk-greeter) Stack trace of thread 464: #0 0x00007f9ef63cf2bd poll (libc.so.6) #1 0x00007f9ef7382bf9 n/a (libglib-2.0.so.0) #2 0x00007f9ef7382d0c g_main_context_iteration (libglib-2.0.so.0) #3 0x00007f9ef7382d51 n/a (libglib-2.0.so.0) #4 0x00007f9ef73a9ac5 n/a (libglib-2.0.so.0) #5 0x00007f9ef6698297 start_thread (libpthread.so.0) #6 0x00007f9ef63d925f __clone (libc.so.6) Stack trace of thread 497: #0 0x00007f9ef63d43b9 syscall (libc.so.6) #1 0x00007f9ef73c7c7a g_cond_wait_until (libglib-2.0.so.0) #2 0x00007f9ef7357121 n/a (libglib-2.0.so.0) #3 0x00007f9ef73576dc g_async_queue_timeout_pop (libglib-2.0.so.0) #4 0x00007f9ef73aa56e n/a (libglib-2.0.so.0) #5 0x00007f9ef73a9ac5 n/a (libglib-2.0.so.0) #6 0x00007f9ef6698297 start_thread (libpthread.so.0) #7 0x00007f9ef63d925f __clone (libc.so.6) Stack trace of thread 466: #0 0x00007f9ef63cf2bd poll (libc.so.6) #1 0x00007f9ef7382bf9 n/a (libglib-2.0.so.0) #2 0x00007f9ef7382f92 g_main_loop_run (libglib-2.0.so.0) #3 0x00007f9ef796a426 n/a (libgio-2.0.so.0) #4 0x00007f9ef73a9ac5 n/a (libglib-2.0.so.0) #5 0x00007f9ef6698297 start_thread (libpthread.so.0) #6 0x00007f9ef63d925f __clone (libc.so.6)