error: Undefined Behavior: atomic store and read-modify-write operations cannot be performed on read-only memory
       see <https://doc.rust-lang.org/nightly/std/sync/atomic/index.html#atomic-accesses-to-read-only-memory> for more information
  --> tests/fail/concurrency/read_only_atomic_cmpxchg.rs:LL:CC
   |
LL |     x.compare_exchange(1, 2, Ordering::Relaxed, Ordering::Relaxed).unwrap_err();
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
   = note: BACKTRACE:
   = note: inside `main` at tests/fail/concurrency/read_only_atomic_cmpxchg.rs:LL:CC

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to 1 previous error