1 files changed, 77 insertions, 0 deletions
diff --git a/src/runtime/futex_test.go b/src/runtime/futex_test.go
new file mode 100644
index 000000000..f57fc52b8
--- /dev/null
+++ b/src/runtime/futex_test.go
@@ -0,0 +1,77 @@
+// Copyright 2013 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Futex is only available on DragonFly BSD, FreeBSD and Linux.
+// The race detector emits calls to split stack functions so it breaks
+// the test.
+
+// +build dragonfly freebsd linux
+// +build !race
+
+package runtime_test
+
+import (
+	"runtime"
+	"testing"
+	"time"
+)
+
+type futexsleepTest struct {
+	mtx uint32
+	ns  int64
+	msg string
+	ch  chan futexsleepTest
+}
+
+var futexsleepTests = []futexsleepTest{
+	beforeY2038: {mtx: 0, ns: 86400 * 1e9, msg: "before the year 2038", ch: make(chan futexsleepTest, 1)},
+	afterY2038:  {mtx: 0, ns: (1<<31 + 100) * 1e9, msg: "after the year 2038", ch: make(chan futexsleepTest, 1)},
+}
+
+const (
+	beforeY2038 = iota
+	afterY2038
+)
+
+func TestFutexsleep(t *testing.T) {
+	if runtime.GOMAXPROCS(0) > 1 {
+		// futexsleep doesn't handle EINTR or other signals,
+		// so spurious wakeups may happen.
+		t.Skip("skipping; GOMAXPROCS>1")
+	}
+
+	start := time.Now()
+	for _, tt := range futexsleepTests {
+		go func(tt futexsleepTest) {
+			runtime.Entersyscall()
+			runtime.Futexsleep(&tt.mtx, tt.mtx, tt.ns)
+			runtime.Exitsyscall()
+			tt.ch <- tt
+		}(tt)
+	}
+loop:
+	for {
+		select {
+		case tt := <-futexsleepTests[beforeY2038].ch:
+			t.Errorf("futexsleep test %q finished early after %s", tt.msg, time.Since(start))
+			break loop
+		case tt := <-futexsleepTests[afterY2038].ch:
+			// Looks like FreeBSD 10 kernel has changed
+			// the semantics of timedwait on userspace
+			// mutex to make broken stuff look broken.
+			switch {
+			case runtime.GOOS == "freebsd" && runtime.GOARCH == "386":
+				t.Log("freebsd/386 may not work correctly after the year 2038, see golang.org/issue/7194")
+			default:
+				t.Errorf("futexsleep test %q finished early after %s", tt.msg, time.Since(start))
+				break loop
+			}
+		case <-time.After(time.Second):
+			break loop
+		}
+	}
+	for _, tt := range futexsleepTests {
+		runtime.Futexwakeup(&tt.mtx, 1)
+	}
+}