1 files changed, 30 insertions, 0 deletions
diff --git a/src/runtime/runtime_mmap_test.go b/src/runtime/runtime_mmap_test.go
new file mode 100644
index 0000000000..ff5e733cb0
--- /dev/null
+++ b/src/runtime/runtime_mmap_test.go
@@ -0,0 +1,30 @@
+// Copyright 2016 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.
+
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+
+package runtime_test
+
+import (
+	"runtime"
+	"runtime/internal/sys"
+	"testing"
+)
+
+// Test that the error value returned by mmap is positive, as that is
+// what the code in mem_bsd.go, mem_darwin.go, and mem_linux.go expects.
+// See the uses of ENOMEM in sysMap in those files.
+func TestMmapErrorSign(t *testing.T) {
+	p := runtime.Mmap(nil, ^uintptr(0)&^(sys.PhysPageSize-1), 0, runtime.MAP_ANON|runtime.MAP_PRIVATE, -1, 0)
+
+	// The runtime.mmap function is nosplit, but t.Errorf is not.
+	// Reset the pointer so that we don't get an "invalid stack
+	// pointer" error from t.Errorf if we call it.
+	v := uintptr(p)
+	p = nil
+
+	if v != runtime.ENOMEM {
+		t.Errorf("mmap = %v, want %v", v, runtime.ENOMEM)
+	}
+}