Why BleRadio requires static lifetimes for its buffers?

[dzervas]

https://github.com/jonas-schievink/rubble/blob/17bb8bd292bfe644f85aa185358ff9107df9fd2d/rubble-nrf5x/src/radio.rs#L74-L80

I'm not any kind of a guru in Rust and I'm trying to get rubble to play without rtic (btw: it works! :tada: ). The only hacky thing I had to do was this:

    static mut BLE_TX_BUF: PacketBuffer = [0; MIN_PDU_BUF];
    static mut BLE_RX_BUF: PacketBuffer = [0; MIN_PDU_BUF];
    let mut radio = unsafe { BleRadio::new(
        board.RADIO,
        &board.FICR,
        &mut BLE_TX_BUF,
        &mut BLE_RX_BUF,
    ) };

I don't get why BleRadio would require 'static - you need the references to be alive as long BleRadio instance is alive - no?

If there's no particular reason, do you want me to open an MR?

BTW: GREAT, FUCKING GREAT work, thank you for your project

[jonas-schievink]

The buffers need to have 'static lifetime because the radio uses DMA to access them. This is somewhat tricky to handle correctly, since the BleRadio can be dropped or leaked while the radio still has access to the buffer, so it might write to deallocated memory if we don't require a 'static lifetime there.

[dzervas]

hmm, ok, that covers my question. I guess it's a difficult problem to solve - if I do happen to solve it, I'll make an MR.