diff --git a/src/runtime/crash_test.go b/src/runtime/crash_test.go
index 309777d696..a2f0926599 100644
--- a/src/runtime/crash_test.go
+++ b/src/runtime/crash_test.go
@@ -49,6 +49,7 @@ func runTestProg(t *testing.T, binary, name string, env ...string) string {
 	}
 
 	testenv.MustHaveGoBuild(t)
+	t.Helper()
 
 	exe, err := buildTestProg(t, binary)
 	if err != nil {
@@ -135,13 +136,15 @@ func buildTestProg(t *testing.T, binary string, flags ...string) (string, error)
 
 		exe := filepath.Join(dir, name+".exe")
 
-		t.Logf("running go build -o %s %s", exe, strings.Join(flags, " "))
+		start := time.Now()
 		cmd := exec.Command(testenv.GoToolPath(t), append([]string{"build", "-o", exe}, flags...)...)
+		t.Logf("running %v", cmd)
 		cmd.Dir = "testdata/" + binary
 		out, err := testenv.CleanCmdEnv(cmd).CombinedOutput()
 		if err != nil {
 			target.err = fmt.Errorf("building %s %v: %v\n%s", binary, flags, err, out)
 		} else {
+			t.Logf("built %v in %v", name, time.Since(start))
 			target.exe = exe
 			target.err = nil
 		}
diff --git a/src/runtime/testdata/testprogcgo/lockosthread.go b/src/runtime/testdata/testprogcgo/lockosthread.go
index 8fcea35f52..e6dce36fb3 100644
--- a/src/runtime/testdata/testprogcgo/lockosthread.go
+++ b/src/runtime/testdata/testprogcgo/lockosthread.go
@@ -94,7 +94,7 @@ func LockOSThreadAlt() {
 		// Exit with the thread locked.
 	}()
 	<-ready
-	for i := 0; i < 100; i++ {
+	for {
 		time.Sleep(1 * time.Millisecond)
 		// Check that this goroutine is running on a different thread.
 		self := C.pthread_self()
@@ -107,6 +107,4 @@ func LockOSThreadAlt() {
 			return
 		}
 	}
-	println("sub thread still running")
-	os.Exit(1)
 }