ipn/ipnlocal: do controlclient.Shutdown in a different goroutine

We do not need to wait for it to complete. And we might have to
call Shutdown from callback from the controlclient which might
already be holding a lock that Shutdown requires.

Updates #713

Signed-off-by: Maisem Ali <maisem@tailscale.com>

ipn/ipnlocal/local.go

@@ -1141,9 +1141,7 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 		// into sync with the minimal changes. But that's not how it
 		// is right now, which is a sign that the code is still too
 		// complicated.
-		b.mu.Unlock()
+		b.resetControlClientLockedAsync()
-		b.cc.Shutdown()
-		b.mu.Lock()
 	}
 	httpTestClient := b.httpTestClient
 
@@ -1956,7 +1954,7 @@ func (b *LocalBackend) InServerMode() bool {
 }
 
 // Login implements Backend.
-// As of 2022-02-17, this is only exists for tests.
+// As of 2022-11-15, this is only exists for Android.
 func (b *LocalBackend) Login(token *tailcfg.Oauth2Token) {
 	b.mu.Lock()
 	b.assertClientLocked()
@@ -3128,7 +3126,6 @@ func (b *LocalBackend) hasNodeKey() bool {
 // its internal state.
 func (b *LocalBackend) nextState() ipn.State {
 	b.mu.Lock()
-	b.assertClientLocked()
 	var (
 		cc         = b.cc
 		netMap     = b.netMap
@@ -3150,7 +3147,7 @@ func (b *LocalBackend) nextState() ipn.State {
 	case !wantRunning && !loggedOut && !blocked && b.hasNodeKey():
 		return ipn.Stopped
 	case netMap == nil:
-		if cc.AuthCantContinue() || loggedOut {
+		if (cc != nil && cc.AuthCantContinue()) || loggedOut {
 			// Auth was interrupted or waiting for URL visit,
 			// so it won't proceed without human help.
 			return ipn.NeedsLogin
@@ -3238,6 +3235,18 @@ func (b *LocalBackend) requestEngineStatusAndWait() {
 	b.statusLock.Unlock()
 }
 
+// resetControlClientLockedAsync sets b.cc to nil, and starts a
+// goroutine to Shutdown the old client. It does not wait for the
+// shutdown to complete.
+func (b *LocalBackend) resetControlClientLockedAsync() {
+	if b.cc == nil {
+		return
+	}
+	go b.cc.Shutdown()
+	b.cc = nil
+	b.ccAuto = nil
+}
+
 // ResetForClientDisconnect resets the backend for GUI clients running
 // in interactive (non-headless) mode. This is currently used only by
 // Windows. This causes all state to be cleared, lest an unrelated user
@@ -3249,11 +3258,7 @@ func (b *LocalBackend) ResetForClientDisconnect() {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 	b.logf("LocalBackend.ResetForClientDisconnect")
-
+	b.resetControlClientLockedAsync()
-	if b.cc != nil {
-		go b.cc.Shutdown()
-		b.cc = nil
-	}
 	b.setNetMapLocked(nil)
 	b.pm.Reset()
 	b.keyExpired = false

ipn/ipnlocal/state_test.go

@@ -92,29 +92,42 @@ func (nt *notifyThrottler) drain(count int) []ipn.Notify {
 // the state machine works as expected.
 type mockControl struct {
 	tb     testing.TB
+	logf   logger.Logf
 	opts   controlclient.Options
-	logfActual logger.Logf
+	paused atomic.Bool
-	statusFunc func(controlclient.Status)
 
 	mu          sync.Mutex
+	machineKey  key.MachinePrivate
+	persist     *persist.Persist
 	calls       []string
 	authBlocked bool
-	persist     *persist.Persist
+	shutdown    chan struct{}
-	machineKey  key.MachinePrivate
 }
 
-func newMockControl(tb testing.TB) *mockControl {
+func newClient(tb testing.TB, opts controlclient.Options) *mockControl {
 	return &mockControl{
 		tb:          tb,
 		authBlocked: true,
+		logf:        opts.Logf,
+		opts:        opts,
+		shutdown:    make(chan struct{}),
+		persist:     opts.Persist.Clone(),
 	}
 }
 
-func (cc *mockControl) logf(format string, args ...any) {
+func (cc *mockControl) assertShutdown(wasPaused bool) {
-	if cc.logfActual == nil {
+	cc.tb.Helper()
-		return
+	select {
+	case <-cc.shutdown:
+		// ok
+	case <-time.After(500 * time.Millisecond):
+		cc.tb.Fatalf("timed out waiting for shutdown")
+	}
+	if wasPaused {
+		cc.assertCalls("unpause", "Shutdown")
+	} else {
+		cc.assertCalls("Shutdown")
 	}
-	cc.logfActual(format, args...)
 }
 
 func (cc *mockControl) populateKeys() (newKeys bool) {
@@ -143,7 +156,12 @@ func (cc *mockControl) populateKeys() (newKeys bool) {
 // send publishes a controlclient.Status notification upstream.
 // (In our tests here, upstream is the ipnlocal.Local instance.)
 func (cc *mockControl) send(err error, url string, loginFinished bool, nm *netmap.NetworkMap) {
-	if cc.statusFunc != nil {
+	if loginFinished {
+		cc.mu.Lock()
+		cc.authBlocked = false
+		cc.mu.Unlock()
+	}
+	if cc.opts.Status != nil {
 		pv := cc.persist.View()
 		s := controlclient.Status{
 			URL:     url,
@@ -156,7 +174,7 @@ func (cc *mockControl) send(err error, url string, loginFinished bool, nm *netma
 		} else if url == "" && err == nil && nm == nil {
 			s.LogoutFinished = &empty.Message{}
 		}
-		cc.statusFunc(s)
+		cc.opts.Status(s)
 	}
 }
 
@@ -178,34 +196,16 @@ func (cc *mockControl) assertCalls(want ...string) {
 	cc.calls = nil
 }
 
-// setAuthBlocked changes the return value of AuthCantContinue.
-// Auth is blocked if you haven't called Login, the control server hasn't
-// provided an auth URL, or it has provided an auth URL and you haven't
-// visited it yet.
-func (cc *mockControl) setAuthBlocked(blocked bool) {
-	cc.mu.Lock()
-	defer cc.mu.Unlock()
-
-	cc.authBlocked = blocked
-}
-
 // Shutdown disconnects the client.
-//
-// Note that in a normal controlclient, Shutdown would be the last thing you
-// do before discarding the object. In this mock, we don't actually discard
-// the object, but if you see a call to Shutdown, you should always see a
-// call to New right after it, if the object continues to be used.
-// (Note that "New" is the ccGen function here; it means ipn.Backend wanted
-// to create an entirely new controlclient.)
 func (cc *mockControl) Shutdown() {
 	cc.logf("Shutdown")
 	cc.called("Shutdown")
+	close(cc.shutdown)
 }
 
-// Login starts a login process.
+// Login starts a login process. Note that in this mock, we don't automatically
-// Note that in this mock, we don't automatically generate notifications
+// generate notifications about the progress of the login operation. You have to
-// about the progress of the login operation. You have to call setAuthBlocked()
+// call send() as required by the test.
-// and send() as required by the test.
 func (cc *mockControl) Login(t *tailcfg.Oauth2Token, flags controlclient.LoginFlags) {
 	cc.logf("Login token=%v flags=%v", t, flags)
 	cc.called("Login")
@@ -213,7 +213,9 @@ func (cc *mockControl) Login(t *tailcfg.Oauth2Token, flags controlclient.LoginFl
 
 	interact := (flags & controlclient.LoginInteractive) != 0
 	cc.logf("Login: interact=%v newKeys=%v", interact, newKeys)
-	cc.setAuthBlocked(interact || newKeys)
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	cc.authBlocked = interact || newKeys
 }
 
 func (cc *mockControl) StartLogout() {
@@ -228,6 +230,10 @@ func (cc *mockControl) Logout(ctx context.Context) error {
 }
 
 func (cc *mockControl) SetPaused(paused bool) {
+	was := cc.paused.Swap(paused)
+	if was == paused {
+		return
+	}
 	cc.logf("SetPaused=%v", paused)
 	if paused {
 		cc.called("pause")
@@ -303,16 +309,10 @@ func TestStateMachine(t *testing.T) {
 		t.Fatalf("NewLocalBackend: %v", err)
 	}
 
-	cc := newMockControl(t)
+	var cc, previousCC *mockControl
-	cc.statusFunc = b.setClientStatus
-
 	b.SetControlClientGetterForTesting(func(opts controlclient.Options) (controlclient.Client, error) {
-		cc.mu.Lock()
+		previousCC = cc
-		cc.opts = opts
+		cc = newClient(t, opts)
-		cc.logfActual = opts.Logf
-		cc.authBlocked = true
-		cc.persist = cc.opts.Persist.Clone()
-		cc.mu.Unlock()
 
 		t.Logf("ccGen: new mockControl.")
 		cc.called("New")
@@ -336,7 +336,7 @@ func TestStateMachine(t *testing.T) {
 
 	// Check that it hasn't called us right away.
 	// The state machine should be idle until we call Start().
-	cc.assertCalls()
+	c.Assert(cc, qt.IsNil)
 
 	// Start the state machine.
 	// Since !WantRunning by default, it'll create a controlclient,
@@ -346,7 +346,7 @@ func TestStateMachine(t *testing.T) {
 	c.Assert(b.Start(ipn.Options{}), qt.IsNil)
 	{
 		// BUG: strictly, it should pause, not unpause, here, since !WantRunning.
-		cc.assertCalls("New", "unpause")
+		cc.assertCalls("New")
 
 		nn := notifies.drain(2)
 		cc.assertCalls()
@@ -370,8 +370,8 @@ func TestStateMachine(t *testing.T) {
 	notifies.expect(2)
 	c.Assert(b.Start(ipn.Options{}), qt.IsNil)
 	{
-		// BUG: strictly, it should pause, not unpause, here, since !WantRunning.
+		previousCC.assertShutdown(false)
-		cc.assertCalls("Shutdown", "unpause", "New", "unpause")
+		cc.assertCalls("New")
 
 		nn := notifies.drain(2)
 		cc.assertCalls()
@@ -397,6 +397,7 @@ func TestStateMachine(t *testing.T) {
 		// (This behaviour is needed so that b.Login() won't
 		// start connecting to an old account right away, if one
 		// exists when you launch another login.)
+		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
 	}
 
 	// Attempted non-interactive login with no key; indicate that
@@ -406,7 +407,7 @@ func TestStateMachine(t *testing.T) {
 	url1 := "http://localhost:1/1"
 	cc.send(nil, url1, false, nil)
 	{
-		cc.assertCalls("unpause")
+		cc.assertCalls()
 
 		// ...but backend eats that notification, because the user
 		// didn't explicitly request interactive login yet, and
@@ -416,6 +417,7 @@ func TestStateMachine(t *testing.T) {
 		c.Assert(nn[0].Prefs, qt.IsNotNil)
 		c.Assert(nn[0].Prefs.LoggedOut(), qt.IsFalse)
 		c.Assert(nn[0].Prefs.WantRunning(), qt.IsFalse)
+		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
 	}
 
 	// Now we'll try an interactive login.
@@ -427,9 +429,10 @@ func TestStateMachine(t *testing.T) {
 	b.StartLoginInteractive()
 	{
 		nn := notifies.drain(1)
-		cc.assertCalls("unpause")
+		cc.assertCalls()
 		c.Assert(nn[0].BrowseToURL, qt.IsNotNil)
 		c.Assert(url1, qt.Equals, *nn[0].BrowseToURL)
+		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
 	}
 
 	// Sometimes users press the Login button again, in the middle of
@@ -444,6 +447,7 @@ func TestStateMachine(t *testing.T) {
 		notifies.drain(0)
 		// backend asks control for another login sequence
 		cc.assertCalls("Login")
+		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
 	}
 
 	// Provide a new interactive login URL.
@@ -452,13 +456,14 @@ func TestStateMachine(t *testing.T) {
 	url2 := "http://localhost:1/2"
 	cc.send(nil, url2, false, nil)
 	{
-		cc.assertCalls("unpause", "unpause")
+		cc.assertCalls()
 
 		// This time, backend should emit it to the UI right away,
 		// because the UI is anxiously awaiting a new URL to visit.
 		nn := notifies.drain(1)
 		c.Assert(nn[0].BrowseToURL, qt.IsNotNil)
 		c.Assert(url2, qt.Equals, *nn[0].BrowseToURL)
+		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
 	}
 
 	// Pretend that the interactive login actually happened.
@@ -467,7 +472,6 @@ func TestStateMachine(t *testing.T) {
 	// The backend should propagate this upward for the UI.
 	t.Logf("\n\nLoginFinished")
 	notifies.expect(3)
-	cc.setAuthBlocked(false)
 	cc.persist.LoginName = "user1"
 	cc.send(nil, "", true, &netmap.NetworkMap{})
 	{
@@ -480,12 +484,13 @@ func TestStateMachine(t *testing.T) {
 		// wait until it gets into Starting.
 		// TODO: (Currently this test doesn't detect that bug, but
 		// it's visible in the logs)
-		cc.assertCalls("unpause", "unpause", "unpause")
+		cc.assertCalls()
 		c.Assert(nn[0].LoginFinished, qt.IsNotNil)
 		c.Assert(nn[1].Prefs, qt.IsNotNil)
 		c.Assert(nn[2].State, qt.IsNotNil)
 		c.Assert(nn[1].Prefs.Persist().LoginName, qt.Equals, "user1")
 		c.Assert(ipn.NeedsMachineAuth, qt.Equals, *nn[2].State)
+		c.Assert(ipn.NeedsMachineAuth, qt.Equals, b.State())
 	}
 
 	// Pretend that the administrator has authorized our machine.
@@ -502,7 +507,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(1)
-		cc.assertCalls("unpause", "unpause", "unpause")
+		cc.assertCalls()
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(ipn.Starting, qt.Equals, *nn[0].State)
 	}
@@ -543,7 +548,7 @@ func TestStateMachine(t *testing.T) {
 	{
 		nn := notifies.drain(2)
 		// BUG: Login isn't needed here. We never logged out.
-		cc.assertCalls("Login", "unpause", "unpause")
+		cc.assertCalls("Login", "unpause")
 		// BUG: I would expect Prefs to change first, and state after.
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(nn[1].Prefs, qt.IsNotNil)
@@ -580,7 +585,7 @@ func TestStateMachine(t *testing.T) {
 	b.Logout()
 	{
 		nn := notifies.drain(2)
-		cc.assertCalls("pause", "StartLogout", "pause")
+		cc.assertCalls("pause", "StartLogout")
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(nn[1].Prefs, qt.IsNotNil)
 		c.Assert(ipn.Stopped, qt.Equals, *nn[0].State)
@@ -593,11 +598,11 @@ func TestStateMachine(t *testing.T) {
 	// Let's make the logout succeed.
 	t.Logf("\n\nLogout (async) - succeed")
 	notifies.expect(3)
-	cc.setAuthBlocked(true)
 	cc.send(nil, "", false, nil)
 	{
+		previousCC.assertShutdown(true)
 		nn := notifies.drain(3)
-		cc.assertCalls("unpause", "unpause", "Shutdown", "unpause", "New", "unpause")
+		cc.assertCalls("New")
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(*nn[0].State, qt.Equals, ipn.NoState)
 		c.Assert(nn[1].Prefs, qt.IsNotNil) // emptyPrefs
@@ -617,7 +622,7 @@ func TestStateMachine(t *testing.T) {
 		c.Assert(nn[0].Prefs, qt.IsNotNil) // emptyPrefs
 		// BUG: the backend has already called StartLogout, and we're
 		// still logged out. So it shouldn't call it again.
-		cc.assertCalls("StartLogout", "unpause")
+		cc.assertCalls("StartLogout")
 		cc.assertCalls()
 		c.Assert(b.Prefs().LoggedOut(), qt.IsTrue)
 		c.Assert(b.Prefs().WantRunning(), qt.IsFalse)
@@ -627,7 +632,6 @@ func TestStateMachine(t *testing.T) {
 	// Let's acknowledge the second logout too.
 	t.Logf("\n\nLogout2 (async) - succeed")
 	notifies.expect(0)
-	cc.setAuthBlocked(true)
 	cc.send(nil, "", false, nil)
 	{
 		notifies.drain(0)
@@ -645,7 +649,7 @@ func TestStateMachine(t *testing.T) {
 	// I guess, since that's supposed to be synchronous.
 	{
 		notifies.drain(0)
-		cc.assertCalls("Logout", "unpause")
+		cc.assertCalls("Logout")
 		c.Assert(b.Prefs().LoggedOut(), qt.IsTrue)
 		c.Assert(b.Prefs().WantRunning(), qt.IsFalse)
 		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
@@ -654,7 +658,6 @@ func TestStateMachine(t *testing.T) {
 	// Generate the third logout event.
 	t.Logf("\n\nLogout3 (sync) - succeed")
 	notifies.expect(0)
-	cc.setAuthBlocked(true)
 	cc.send(nil, "", false, nil)
 	{
 		notifies.drain(0)
@@ -676,9 +679,10 @@ func TestStateMachine(t *testing.T) {
 	notifies.expect(2)
 	c.Assert(b.Start(ipn.Options{}), qt.IsNil)
 	{
+		previousCC.assertShutdown(false)
 		// BUG: We already called Shutdown(), no need to do it again.
 		// BUG: don't unpause because we're not logged in.
-		cc.assertCalls("Shutdown", "unpause", "New", "unpause")
+		cc.assertCalls("New")
 
 		nn := notifies.drain(2)
 		cc.assertCalls()
@@ -693,14 +697,13 @@ func TestStateMachine(t *testing.T) {
 	b.Login(nil)
 	t.Logf("\n\nLoginFinished3")
 	notifies.expect(3)
-	cc.setAuthBlocked(false)
 	cc.persist.LoginName = "user2"
 	cc.send(nil, "", true, &netmap.NetworkMap{
 		MachineStatus: tailcfg.MachineAuthorized,
 	})
 	{
 		nn := notifies.drain(3)
-		cc.assertCalls("Login", "unpause", "unpause", "unpause")
+		cc.assertCalls("Login")
 		c.Assert(nn[0].LoginFinished, qt.IsNotNil)
 		c.Assert(nn[1].Prefs, qt.IsNotNil)
 		c.Assert(nn[1].Prefs.Persist(), qt.IsNotNil)
@@ -736,12 +739,14 @@ func TestStateMachine(t *testing.T) {
 	{
 		// NOTE: cc.Shutdown() is correct here, since we didn't call
 		// b.Shutdown() explicitly ourselves.
+		previousCC.assertShutdown(false)
+
 		// Note: unpause happens because ipn needs to get at least one netmap
 		//  on startup, otherwise UIs can't show the node list, login
 		//  name, etc when in state ipn.Stopped.
 		//  Arguably they shouldn't try. But they currently do.
 		nn := notifies.drain(2)
-		cc.assertCalls("Shutdown", "unpause", "New", "Login", "unpause")
+		cc.assertCalls("New", "Login")
 		c.Assert(nn[0].Prefs, qt.IsNotNil)
 		c.Assert(nn[1].State, qt.IsNotNil)
 		c.Assert(nn[0].Prefs.WantRunning(), qt.IsFalse)
@@ -765,7 +770,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		notifies.drain(0)
-		cc.assertCalls("pause", "pause")
+		cc.assertCalls("pause")
 	}
 
 	// Request connection.
@@ -778,7 +783,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(2)
-		cc.assertCalls("Login", "unpause", "unpause")
+		cc.assertCalls("Login", "unpause")
 		// BUG: I would expect Prefs to change first, and state after.
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(nn[1].Prefs, qt.IsNotNil)
@@ -817,7 +822,7 @@ func TestStateMachine(t *testing.T) {
 		//
 		// Because the login hasn't yet completed, the old login
 		// is still valid, so it's correct that we stay paused.
-		cc.assertCalls("Login", "pause", "pause")
+		cc.assertCalls("Login")
 		c.Assert(nn[0].BrowseToURL, qt.IsNotNil)
 		c.Assert(*nn[0].BrowseToURL, qt.Equals, url3)
 	}
@@ -839,7 +844,7 @@ func TestStateMachine(t *testing.T) {
 		//  and !WantRunning. But since it's a fresh and successful
 		//  new login, WantRunning is true, so there was never a
 		//  reason to pause().
-		cc.assertCalls("pause", "unpause", "unpause")
+		cc.assertCalls("unpause")
 		c.Assert(nn[0].LoginFinished, qt.IsNotNil)
 		c.Assert(nn[1].Prefs, qt.IsNotNil)
 		c.Assert(nn[2].State, qt.IsNotNil)
@@ -853,35 +858,35 @@ func TestStateMachine(t *testing.T) {
 	// The last test case is the most common one: restarting when both
 	// logged in and WantRunning.
 	t.Logf("\n\nStart5")
-	notifies.expect(1)
+	notifies.expect(2)
 	c.Assert(b.Start(ipn.Options{}), qt.IsNil)
 	{
 		// NOTE: cc.Shutdown() is correct here, since we didn't call
 		// b.Shutdown() ourselves.
-		cc.assertCalls("Shutdown", "unpause", "New", "Login", "unpause")
+		previousCC.assertShutdown(false)
+		cc.assertCalls("New", "Login")
 
-		nn := notifies.drain(1)
+		nn := notifies.drain(2)
 		cc.assertCalls()
 		c.Assert(nn[0].Prefs, qt.IsNotNil)
 		c.Assert(nn[0].Prefs.LoggedOut(), qt.IsFalse)
 		c.Assert(nn[0].Prefs.WantRunning(), qt.IsTrue)
-		c.Assert(ipn.NoState, qt.Equals, b.State())
+		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
 	}
 
 	// Control server accepts our valid key from before.
 	t.Logf("\n\nLoginFinished5")
-	notifies.expect(1)
+	notifies.expect(2)
-	cc.setAuthBlocked(false)
 	cc.send(nil, "", true, &netmap.NetworkMap{
 		MachineStatus: tailcfg.MachineAuthorized,
 	})
 	{
-		nn := notifies.drain(1)
+		nn := notifies.drain(2)
-		cc.assertCalls("unpause", "unpause", "unpause")
+		cc.assertCalls()
 		// NOTE: No LoginFinished message since no interactive
 		// login was needed.
-		c.Assert(nn[0].State, qt.IsNotNil)
+		c.Assert(nn[1].State, qt.IsNotNil)
-		c.Assert(ipn.Starting, qt.Equals, *nn[0].State)
+		c.Assert(ipn.Starting, qt.Equals, *nn[1].State)
 		// NOTE: No prefs change this time. WantRunning stays true.
 		// We were in Starting in the first place, so that doesn't
 		// change either.
@@ -895,7 +900,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(1)
-		cc.assertCalls("unpause", "unpause")
+		cc.assertCalls()
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(ipn.NeedsLogin, qt.Equals, *nn[0].State)
 		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
@@ -910,7 +915,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(1)
-		cc.assertCalls("unpause", "unpause", "unpause")
+		cc.assertCalls()
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(ipn.Starting, qt.Equals, *nn[0].State)
 		c.Assert(ipn.Starting, qt.Equals, b.State())
@@ -921,7 +926,7 @@ func TestStateMachine(t *testing.T) {
 	b.setWgengineStatus(&wgengine.Status{DERPs: 1, AsOf: time.Now()}, nil)
 	{
 		nn := notifies.drain(1)
-		cc.assertCalls("unpause")
+		cc.assertCalls()
 		c.Assert(nn[0].State, qt.IsNotNil)
 		c.Assert(ipn.Running, qt.Equals, *nn[0].State)
 		c.Assert(ipn.Running, qt.Equals, b.State())
@@ -1017,11 +1022,9 @@ func TestWGEngineStatusRace(t *testing.T) {
 	b, err := NewLocalBackend(logf, "logid", new(mem.Store), "", nil, eng, 0)
 	c.Assert(err, qt.IsNil)
 
-	cc := newMockControl(t)
+	var cc *mockControl
 	b.SetControlClientGetterForTesting(func(opts controlclient.Options) (controlclient.Client, error) {
-		cc.mu.Lock()
+		cc = newClient(t, opts)
-		defer cc.mu.Unlock()
-		cc.logfActual = opts.Logf
 		return cc, nil
 	})