@fantasia you should really ask someone who is voicing this concern on the Linux kernel team. I don't know anything about the specifs of C and Rust interoperability, the data structures used, if they're stable/reliable and there are no problems serializing/deserializing them, etc but that is one of their major concerns.

We may even see Rust restricted to out of tree modules or only specific areas of the kernel where it's less likely to be dangerous, or where the module could only ever be used on specific architectures that Rust targets.