First: That's a strawman. Nobody's saying we can't ever use new features, just that it's reasonable to be cautious with new code that demonstrably has a history

First: That's a strawman. Nobody's saying we can't ever use new features, just that it's reasonable to be cautious with new code that demonstrably has a history of problems. When io_uring has a few decades under its belt I expect its use to be uncontroversial. Second: That's... not a terrible idea. Concurrency bugs do crop up from time to time. I wouldn't use it for everything (again, we're in the very long tail of concurrency bugs), but having a way to force the system into a mode that couldn't hit them would be nice for high-stakes situations (the same way that Apple's Lockdown Mode disables JIT in the browser). Unfortunately it would probably be more involved than a sysctl.