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// We want to control preemption here. Stacked borrows interferes by having its own accesses.
//@compile-flags: -Zmiri-deterministic-concurrency -Zmiri-disable-stacked-borrows
use std::sync::atomic::{AtomicUsize, Ordering};
use std::thread::{sleep, spawn};
use std::time::Duration;
#[derive(Copy, Clone)]
struct EvilSend<T>(pub T);
unsafe impl<T> Send for EvilSend<T> {}
unsafe impl<T> Sync for EvilSend<T> {}
static SYNC: AtomicUsize = AtomicUsize::new(0);
pub fn main() {
let mut a = 0u32;
let b = &mut a as *mut u32;
let c = EvilSend(b);
// Note: this is scheduler-dependent
// the operations need to occur in
// order, the sleep operations currently
// force the desired ordering:
// 1. store release : 1
// 2. store relaxed : 2
// 3. store relaxed : 3
// 4. load acquire : 3
unsafe {
let j1 = spawn(move || {
let c = c; // avoid field capturing
*c.0 = 1;
SYNC.store(1, Ordering::Release);
sleep(Duration::from_millis(200));
SYNC.store(3, Ordering::Relaxed);
});
let j2 = spawn(move || {
// Blocks the acquire-release sequence
SYNC.store(2, Ordering::Relaxed);
});
let j3 = spawn(move || {
let c = c; // avoid field capturing
sleep(Duration::from_millis(500));
if SYNC.load(Ordering::Acquire) == 3 {
*c.0 //~ ERROR: Data race detected between (1) non-atomic write on thread `unnamed-1` and (2) non-atomic read on thread `unnamed-3`
} else {
0
}
});
j1.join().unwrap();
j2.join().unwrap();
j3.join().unwrap();
}
}
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