Apple chips share the same physical memory between the GPU and the CPU. Still, they don't have USM/UVM (Unified Shared Memory/Unified Virtual Memory), that is, the GPU and the CPU can't access the same data concurrently and easily. Programs must map/unmap pages to control which device accesses it, and that's a very expensive operation.
More like: the Linux kernel re-implementation of Rust "print" has a bug that causes it to not adhere to Linux kernel conventions.
I'd expect that now that the bug has been reported, it'd be fixed by just hashing pointer addresses before printing them.
I also expect that "reimplementing X in a different programming language" introduces logic bugs, like the one above, and that those involved have deemed what they get out of it worth the effort of hashing these sort of bugs long term.
From the kernel pov, all of these bugs are safety issues, so the article authors are surprised the unsafe keyword is not required to introduce them, but from Rust's pov, they are just logic bugs, which safe Rust does not protect against. One of the main challenges those working on Rust in the kernel will have is figuring out how to educate other kernel developers about Rust (what it does and does not protect against, setting the right expectations, etc.). I think these articles are a great step in that direction.