Internal change.

PiperOrigin-RevId: 898158090

Author: gvisor-bot

pkg/sync/gate_test.go

@@ -103,6 +103,27 @@ func testGateConcurrentOnce(t *testing.T, d time.Duration) {
 	time.Sleep(d / 2)
 }
 
+func TestGateRaceReproduction(t *testing.T) {
+	var g Gate
+	var v int32
+	if !g.Enter() {
+		t.Fatalf("Enter failed")
+	}
+	done := make(chan bool)
+	go func() {
+		g.Close()
+		v = 2 // Used to trigger a write/write race.
+		done <- true
+	}()
+	time.Sleep(50 * time.Millisecond)
+	v = 1
+	g.Leave()
+	<-done
+	if v != 2 {
+		t.Errorf("Unexpected value of v: %d", v)
+	}
+}
+
 func BenchmarkGateEnterLeave(b *testing.B) {
 	var g Gate
 	for i := 0; i < b.N; i++ {

pkg/sync/gate_unsafe.go

@@ -110,8 +110,8 @@ func (g *Gate) leaveClosed() {
 	if atomic.LoadUintptr(&g.closingG) == 0 {
 		return
 	}
-	if g := atomic.SwapUintptr(&g.closingG, 0); g > preparingG {
-		goready(g, 0)
+	if cG := atomic.SwapUintptr(&g.closingG, 0); cG > preparingG {
+		goready(cG, 0)
 	}
 }
 
@@ -133,15 +133,16 @@ func (g *Gate) Close() {
 		panic("concurrent Close of sync.Gate")
 	}
 
-	if g := atomic.SwapUintptr(&g.closingG, preparingG); g != 0 {
-		panic(fmt.Sprintf("invalid sync.Gate.closingG during Close: %#x", g))
+	if cG := atomic.SwapUintptr(&g.closingG, preparingG); cG != 0 {
+		panic(fmt.Sprintf("invalid sync.Gate.closingG during Close: %#x", cG))
 	}
 	if atomic.LoadInt32(&g.userCount) == math.MinInt32 {
 		// The last call to Leave arrived while we were setting up closingG.
 		return
 	}
 	// WaitReasonSemacquire/TraceBlockSync are consistent with WaitGroup.
 	gopark(gateCommit, gohacks.Noescape(unsafe.Pointer(&g.closingG)), WaitReasonSemacquire, TraceBlockSync, 0)
+	RaceAcquire(unsafe.Pointer(&g.closingG))
 }
 
 //go:norace