Add tests, and fix bug in atomic RMW relaxed stores

src/data_race.rs

@@ -404,8 +404,9 @@ impl AtomicReleaseSequences {
     fn clear_and_retain(&mut self, thread: ThreadId) {
         match self {
             Self::ReleaseOneOrEmpty(id, rel_clock) => {
-                // Keep or forget depending on id
-                if *id == Some(thread) {
+                // If the id is the same, then reatin the value
+                //  otherwise delete and clear the release vector clock
+                if *id != Some(thread) {
                     *id = None;
                     rel_clock.set_zero_vector();
                 }

src/shims/posix/thread.rs

@@ -15,8 +15,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let this = self.eval_context_mut();
 
         this.tcx.sess.warn(
-            "thread support is experimental. \
-             For example, Miri does not detect data races yet.",
+            "thread support is experimental.",
         );
 
         // Create the new thread

tests/compile-fail/data_race/read_write_race.rs

@@ -0,0 +1,26 @@
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0
+        });
+
+        let j2 = spawn(move || {
+            *c.0 = 64; //~ ERROR Data race
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}

tests/compile-fail/data_race/relax_acquire_race.rs

@@ -0,0 +1,42 @@
+
+use std::thread::spawn;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+#[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);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 1 {
+                SYNC.store(2, Ordering::Relaxed);
+            }
+        });
+
+        let j3 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 2 {
+                *c.0 //~ ERROR Data race
+            }else{
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        j3.join().unwrap();
+    }
+}

tests/compile-fail/data_race/release_seq_race.rs

@@ -0,0 +1,46 @@
+// compile-flags: -Zmiri-disable-isolation
+
+use std::thread::{spawn, sleep};
+use std::sync::atomic::{AtomicUsize, Ordering};
+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);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+            sleep(Duration::from_millis(100));
+            SYNC.store(3, Ordering::Relaxed);
+        });
+
+        let j2 = spawn(move || {
+            // Blocks the acquire-release sequence
+            SYNC.store(2, Ordering::Relaxed);
+        });
+
+        let j3 = spawn(move || {
+            sleep(Duration::from_millis(1000));
+            if SYNC.load(Ordering::Acquire) == 3 {
+                *c.0 //~ ERROR Data race
+            }else{
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        j3.join().unwrap();
+    }
+}

tests/compile-fail/data_race/rmw_race.rs

@@ -0,0 +1,43 @@
+
+use std::thread::spawn;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+#[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);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.swap(2, Ordering::Relaxed) == 1 {
+                // Blocks the acquire-release sequence
+                SYNC.store(3, Ordering::Relaxed);
+            }
+        });
+
+        let j3 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 3 {
+                *c.0 //~ ERROR Data race
+            }else{
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        j3.join().unwrap();
+    }
+}

tests/compile-fail/data_race/write_write_race.rs

@@ -0,0 +1,26 @@
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 32;
+        });
+
+        let j2 = spawn(move || {
+            *c.0 = 64; //~ ERROR Data race
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}

tests/run-pass/concurrency/data_race.rs

@@ -0,0 +1,119 @@
+use std::sync::atomic::{AtomicUsize, fence, Ordering};
+use std::thread::spawn;
+
+#[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);
+
+fn test_fence_sync() {
+    let mut var = 0u32;
+    let ptr = &mut var as *mut u32;
+    let evil_ptr = EvilSend(ptr);
+
+
+    let j1 = spawn(move || {
+        unsafe { *evil_ptr.0 = 1; }
+        fence(Ordering::Release);
+        SYNC.store(1, Ordering::Relaxed)   
+    });
+
+    let j2 = spawn(move || {
+        if SYNC.load(Ordering::Relaxed) == 1 {
+            fence(Ordering::Acquire);
+            unsafe { *evil_ptr.0 }
+        }else{
+            0
+        }
+    });
+
+    j1.join().unwrap();
+    j2.join().unwrap();
+}
+
+
+fn test_multiple_reads() {
+    let mut var = 42u32;
+    let ptr = &mut var as *mut u32;
+    let evil_ptr = EvilSend(ptr);
+
+    let j1 = spawn(move || unsafe {*evil_ptr.0});
+    let j2 = spawn(move || unsafe {*evil_ptr.0});
+    let j3 = spawn(move || unsafe {*evil_ptr.0});
+    let j4 = spawn(move || unsafe {*evil_ptr.0});
+
+    assert_eq!(j1.join().unwrap(), 42);
+    assert_eq!(j2.join().unwrap(), 42);
+    assert_eq!(j3.join().unwrap(), 42);
+    assert_eq!(j4.join().unwrap(), 42);
+
+    var = 10;
+    assert_eq!(var, 10);
+}
+
+pub fn test_rmw_no_block() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.swap(2, Ordering::Relaxed) == 1 {
+                //No op, blocking store removed
+            }
+        });
+
+        let j3 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 2 {
+                *c.0
+            }else{
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        let v = j3.join().unwrap();
+        assert!(v == 1 || v == 2);
+    }
+}
+
+pub fn test_release_no_block() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+            SYNC.store(3, Ordering::Relaxed);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 3 {
+                *c.0
+            }else{
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        assert_eq!(j2.join().unwrap(),1);
+    }
+}
+
+pub fn main() {
+    test_fence_sync();
+    test_multiple_reads();
+    test_rmw_no_block();
+    test_release_no_block();
+}

tests/run-pass/concurrency/data_race.stderr

@@ -0,0 +1,2 @@
+warning: thread support is experimental.
+

tests/run-pass/concurrency/linux-futex.stderr

@@ -1,2 +1,2 @@
-warning: thread support is experimental. For example, Miri does not detect data races yet.
+warning: thread support is experimental.
 

tests/run-pass/concurrency/simple.stderr

@@ -1,4 +1,4 @@
-warning: thread support is experimental. For example, Miri does not detect data races yet.
+warning: thread support is experimental.
 
 thread '<unnamed>' panicked at 'Hello!', $DIR/simple.rs:54:9
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/run-pass/concurrency/sync.stderr

@@ -1,2 +1,2 @@
-warning: thread support is experimental. For example, Miri does not detect data races yet.
+warning: thread support is experimental.
 

tests/run-pass/concurrency/thread_locals.stderr

@@ -1,2 +1,2 @@
-warning: thread support is experimental. For example, Miri does not detect data races yet.
+warning: thread support is experimental.
 

tests/run-pass/concurrency/tls_lib_drop.stderr

@@ -1,2 +1,2 @@
-warning: thread support is experimental. For example, Miri does not detect data races yet.
+warning: thread support is experimental.
 

tests/run-pass/libc.stderr

@@ -1,2 +1,2 @@
-warning: thread support is experimental. For example, Miri does not detect data races yet.
+warning: thread support is experimental.
 

tests/run-pass/panic/concurrent-panic.stderr

@@ -1,4 +1,4 @@
-warning: thread support is experimental. For example, Miri does not detect data races yet.
+warning: thread support is experimental.
 
 Thread 1 starting, will block on mutex
 Thread 1 reported it has started