Add synchronisation for read and write to pass the race test

Author: tiif

src/shims/unix/linux/eventfd.rs

@@ -26,7 +26,7 @@ struct Event {
     /// kernel. This counter is initialized with the value specified in the argument initval.
     counter: u64,
     is_nonblock: bool,
-    _clock: VClock,
+    clock: VClock,
 }
 
 impl FileDescription for Event {
@@ -60,6 +60,8 @@ impl FileDescription for Event {
                 throw_unsup_format!("eventfd: blocking is unsupported");
             }
         } else {
+            // Prevent false alarm in data race detection when doing synchronisation via eventfd.
+            ecx.acquire_clock(&self.clock);
             // Return the counter in the host endianness using the buffer provided by caller.
             let counter_byte: [u8; 8] = match ecx.tcx.sess.target.endian {
                 Endian::Little => self.counter.to_le_bytes(),
@@ -117,6 +119,8 @@ impl FileDescription for Event {
                 throw_unsup_format!("eventfd: blocking is unsupported");
             }
         } else {
+            // Prevent false alarm in data race detection when doing synchronisation via eventfd.
+            self.clock.join(&ecx.release_clock().unwrap());
             self.counter = self.counter.checked_add(num).unwrap();
         }
         Ok(Ok(8))
@@ -174,7 +178,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         let fd = this.machine.fds.insert_fd(FileDescriptor::new(Event {
             counter: val.into(),
             is_nonblock,
-            _clock: VClock::default(),
+            clock: VClock::default(),
         }));
         Ok(Scalar::from_i32(fd))
     }

tests/pass-dep/libc/libc-eventfd.rs

@@ -3,7 +3,7 @@
 use std::thread;
 
 fn main() {
-    //test_read_write();
+    test_read_write();
     test_race();
 }