diff --git a/windows/svc/example/service.go b/windows/svc/example/service.go
index 74c93930..45e4c90f 100644
--- a/windows/svc/example/service.go
+++ b/windows/svc/example/service.go
@@ -27,7 +27,6 @@ func (m *myservice) Execute(args []string, r <-chan svc.ChangeRequest, changes c
 	slowtick := time.Tick(2 * time.Second)
 	tick := fasttick
 	changes <- svc.Status{State: svc.Running, Accepts: cmdsAccepted}
-	elog.Info(1, strings.Join(args, "-"))
 loop:
 	for {
 		select {
@@ -42,6 +41,10 @@ loop:
 				time.Sleep(100 * time.Millisecond)
 				changes <- c.CurrentStatus
 			case svc.Stop, svc.Shutdown:
+				// golang.org/x/sys/windows/svc.TestExample is verifying this output.
+				testOutput := strings.Join(args, "-")
+				testOutput += fmt.Sprintf("-%d", c.Context)
+				elog.Info(1, testOutput)
 				break loop
 			case svc.Pause:
 				changes <- svc.Status{State: svc.Paused, Accepts: cmdsAccepted}
diff --git a/windows/svc/service.go b/windows/svc/service.go
index cda26b54..d6ec7e78 100644
--- a/windows/svc/service.go
+++ b/windows/svc/service.go
@@ -80,6 +80,7 @@ type ChangeRequest struct {
 	EventType     uint32
 	EventData     uintptr
 	CurrentStatus Status
+	Context       uintptr
 }
 
 // Handler is the interface that must be implemented to build Windows service.
@@ -121,12 +122,11 @@ func init() {
 	cRegisterServiceCtrlHandlerExW = a.MustFindProc("RegisterServiceCtrlHandlerExW").Addr()
 }
 
-// The HandlerEx prototype also has a context pointer but since we don't use
-// it at start-up time we don't have to pass it over either.
 type ctlEvent struct {
 	cmd       Cmd
 	eventType uint32
 	eventData uintptr
+	context   uintptr
 	errno     uint32
 }
 
@@ -238,13 +238,12 @@ func (s *service) run() {
 		exitFromHandler <- exitCode{ss, errno}
 	}()
 
-	status := Status{State: Stopped}
 	ec := exitCode{isSvcSpecific: true, errno: 0}
+	outcr := ChangeRequest{
+		CurrentStatus: Status{State: Stopped},
+	}
 	var outch chan ChangeRequest
 	inch := s.c
-	var cmd Cmd
-	var evtype uint32
-	var evdata uintptr
 loop:
 	for {
 		select {
@@ -255,10 +254,11 @@ loop:
 			}
 			inch = nil
 			outch = cmdsToHandler
-			cmd = r.cmd
-			evtype = r.eventType
-			evdata = r.eventData
-		case outch <- ChangeRequest{cmd, evtype, evdata, status}:
+			outcr.Cmd = r.cmd
+			outcr.EventType = r.eventType
+			outcr.EventData = r.eventData
+			outcr.Context = r.context
+		case outch <- outcr:
 			inch = s.c
 			outch = nil
 		case c := <-changesFromHandler:
@@ -271,7 +271,7 @@ loop:
 				}
 				break loop
 			}
-			status = c
+			outcr.CurrentStatus = c
 		case ec = <-exitFromHandler:
 			break loop
 		}
@@ -316,7 +316,7 @@ func Run(name string, handler Handler) error {
 	}
 
 	ctlHandler := func(ctl uint32, evtype uint32, evdata uintptr, context uintptr) uintptr {
-		e := ctlEvent{cmd: Cmd(ctl), eventType: evtype, eventData: evdata}
+		e := ctlEvent{cmd: Cmd(ctl), eventType: evtype, eventData: evdata, context: context}
 		// We assume that this callback function is running on
 		// the same thread as Run. Nowhere in MS documentation
 		// I could find statement to guarantee that. So putting
diff --git a/windows/svc/svc_test.go b/windows/svc/svc_test.go
index feed8fab..8e59c0de 100644
--- a/windows/svc/svc_test.go
+++ b/windows/svc/svc_test.go
@@ -125,7 +125,11 @@ func TestExample(t *testing.T) {
 	if err != nil {
 		t.Fatalf("wevtutil failed: %v\n%v", err, string(out))
 	}
-	if want := strings.Join(append([]string{name}, args...), "-"); !strings.Contains(string(out), want) {
+	want := strings.Join(append([]string{name}, args...), "-")
+	// Test context passing (see servicemain in sys_386.s and sys_amd64.s).
+	// TODO(brainman): Uncomment next line once issue #25660 is fixed.
+	//want += "-123456"
+	if !strings.Contains(string(out), want) {
 		t.Errorf("%q string does not contain %q", string(out), want)
 	}
 }
diff --git a/windows/svc/sys_386.s b/windows/svc/sys_386.s
index 2c82a9d9..c8a583d7 100644
--- a/windows/svc/sys_386.s
+++ b/windows/svc/sys_386.s
@@ -22,7 +22,8 @@ TEXT ·servicemain(SB),7,$0
 	MOVL	AX, (SP)
 	MOVL	$·servicectlhandler(SB), AX
 	MOVL	AX, 4(SP)
-	MOVL	$0, 8(SP)
+	// Set context to 123456 to test issue #25660.
+	MOVL	$123456, 8(SP)
 	MOVL	·cRegisterServiceCtrlHandlerExW(SB), AX
 	MOVL	SP, BP
 	CALL	AX
diff --git a/windows/svc/sys_amd64.s b/windows/svc/sys_amd64.s
index bde25e9c..2f7609c5 100644
--- a/windows/svc/sys_amd64.s
+++ b/windows/svc/sys_amd64.s
@@ -14,6 +14,8 @@ TEXT ·servicemain(SB),7,$0
 	MOVQ	·sName(SB), CX
 	MOVQ	$·servicectlhandler(SB), DX
 	// BUG(pastarmovj): Figure out a way to pass in context in R8.
+	// Set context to 123456 to test issue #25660.
+	MOVQ	$123456, R8
 	MOVQ	·cRegisterServiceCtrlHandlerExW(SB), AX
 	CALL	AX
 	CMPQ	AX, $0