zlacker

>>rvz+(OP)
> Even "safe" rust code in user space will do things like panic when things go wrong (overflows, allocation failures, etc). If you don't realize that that is NOT some kind of true safely[sic], I don't know what to say.

> Not completing the operation at all, is not really any better than getting the wrong answer, it's only more debuggable.

What Linus is saying is 100% right of course - he is trying to set the expectations straight in saying that just because you replaced C code with multi thousands (or whatever huge number) of man months of efforts, corrections and refinements with Rust code it doesn't mean absolute safety is guaranteed. For him as a kernel guy just as when you double free the kernel C code detects it and warns about it Rust will panic abort on overflows/alloc fails etc. To the kernel that is not safety at all - as he points out it is only more debuggable.

He is allowing Rust in the kernel so he understands the fact that Rust allows you to shoot yourself in the foot a lot less than standard C - he is merely pointing out the reality that in kernel space or even user space that does not equate to absolute total safety. And as a chief kernel maintainer he is well within his rights to set the expectation straight that tomorrow's kernel-rust programmers write code with this point in mind.

(IOW as an example he doesn't want to see patches in Rust code that ignore kernel realities for Rust's magical safety guarantee - directly or indirectly allocating large chunks of memory may always fail in the kernel and would need to be accounted for even in Rust code.)

>>blinki+Bb
At least in user space, aborting an operation is much better than incorrect results. But the kernel being incorrect makes user space incorrect as well.

First of all, making a problem both obvious and easier to solve is better. Nothing "only" about it - it's better. Better both for the programmers and for the users. For the programmer the benefit is obvious, for the user problems will simply be more rare, because the benefit the programmer received will make software better faster.

Second, about the behavior. When you attempt to save changes to your document, would you rather have the corruption of your document due to a bug fail with fanfare or succeed silently? How about the web page you visited with embedded malicious JavaScript from a compromised third party, would you rather the web page closed or have your bank details for sale on a foreign forum? When correctness is out the window, you must abort.