[pjmlp]

Shared memory, shared files, hardware DMA, shared database connections to the same database.

You can control safety as much as you feel like from Rust side, there is no way to validate that the data coming into the process memory doesn't get corrupted by the other side, while it is being read from Rust side.

Unless access is built in a way that all parties accessing the resource have to play by the same validation rules before writting into it, OS IPC resources like shared mutexes, semaphores, critical section.

The kind of typical readers-writers algorithms in distributed computing.