Large arena causes memory errors and strange behaviour? about embassy

[dvdsk]

try setting up probe-rs as a debugger: https://probe.rs/docs/tools/debugger/

then call break when the program hangs. You will probably find you end up in the fault handler with a bus error. To solve it try saving space somewhere. On nightly the arena is sized automatically to just the right size saving a bit of memory. Try lowering the amount of ram you use (shrink arrays and objects if you can).

[mkj]

Yep, I'll try and have a look at the actual fault.
The arena fits in available RAM (otherwise it wouldn't link), and the tasks fit in the arena (otherwise it would panic), so I don't think it's an issue of sizes - something else is going wrong.

[Dirbaio]

You have to leave enough RAM for the stack. The stack starts from end of RAM and grows downwards. If it grows too much, it will crash into static data, causing UB. This is not checked at link time because the linker doesn't know how much stack your program uses.

[mkj]

Sorry for the noise, looks like it was just stack size. I was assuming the array in the example was part of task memory, but passing it to black_box() (by value not reference) instead results in another stack copy.