I'm curious to hear more about this use case. The DMA I do in rust is generally static buffers, because I'm not sure how to pass the borrow checker otherwise. (There are ways). Generally, you set up a static [u8] buffer, and pass its pointer to the hardware that's doing the DMAing. Then magic, then the buffer gets read or written by the hardware. In this scenario, the variables never go out of scope. Am I cheating, and avoiding this issue by using static buffers? If the buffer drops during a DMA transfer, I believe UB happens.

I'm suspicious a similar principle happens with memory-mapped flash memory as well, e.g. QSPI.