net: add deadline prolongation test

Currently the test exposes data races on deadline vars.

R=golang-dev, dave, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6845091

diff --git a/src/pkg/net/timeout_test.go b/src/pkg/net/timeout_test.go
index c72758dc063d7bd0e96cb159ba49cc337aeb69ec..9bda4ac9b68f91df5fa27d7e32b7beb1cb2f36eb 100644 (file)
--- a/src/pkg/net/timeout_test.go
+++ b/src/pkg/net/timeout_test.go
@@ -576,3 +576,51 @@ func TestWriteDeadlineBufferAvailable(t *testing.T) {
                t.Errorf("Write error = %v; want timeout", res.err)
        }
 }
+
+// TestProlongTimeout tests concurrent deadline modification.
+// Known to cause data races in the past.
+func TestProlongTimeout(t *testing.T) {
+       switch runtime.GOOS {
+       case "plan9":
+               t.Logf("skipping test on %q", runtime.GOOS)
+               return
+       }
+
+       ln := newLocalListener(t)
+       defer ln.Close()
+       go func() {
+               s, err := ln.Accept()
+               if err != nil {
+                       t.Fatalf("ln.Accept: %v", err)
+               }
+               defer s.Close()
+               s.SetDeadline(time.Now().Add(time.Hour))
+               go func() {
+                       var buf [4096]byte
+                       for {
+                               _, err := s.Write(buf[:])
+                               if err != nil {
+                                       break
+                               }
+                               s.SetDeadline(time.Now().Add(time.Hour))
+                       }
+               }()
+               buf := make([]byte, 1)
+               for {
+                       _, err := s.Read(buf)
+                       if err != nil {
+                               break
+                       }
+                       s.SetDeadline(time.Now().Add(time.Hour))
+               }
+       }()
+       c, err := Dial("tcp", ln.Addr().String())
+       if err != nil {
+               t.Fatalf("DialTCP: %v", err)
+       }
+       defer c.Close()
+       for i := 0; i < 1024; i++ {
+               var buf [1]byte
+               c.Write(buf[:])
+       }
+}