Comment 6 for bug 834686

I don't see anything obviously wrong either. But the stack trace given is memory-corrupted:
 * The line it points to in the source is just a g_strdup.
 * The memory passed to g_object_unref is the __tmp6__ pointer, which is just a string.
 * cairo_pattern_create_rgb is high up in the stack (which then apparently calls __libc_start_main...)

So it may not be a bug in settings-daemon.vala itself.