Comment # 3 on bug 906192 from Frederic Crozat

Under linux, ctrl-alt-del doesn't have any more power than any other regular
keystrokes. This means if something (X11 usually) is going crazy, pressing
Ctrl-alt-del won't do a thing. There is nothing a desktop environment can do.
Maybe things will improve in the future with Wayland, but I'm not even sure of
that.

I suggest you open bug reports on the freeze you encounter.

Closing this bug as wontfix.