@@ -1518,14 +1518,11 @@ func (a *agent) runCoordinator(ctx context.Context, tClient tailnetproto.DRPCTai
15181518a .logger .Info (ctx ,"connected to coordination RPC" )
15191519
15201520// This allows the Close() routine to wait for the coordinator to gracefully disconnect.
1521- a . closeMutex . Lock ()
1522- if a . isClosed () {
1523- return nil
1521+ disconnected := a . setCoordDisconnected ()
1522+ if disconnected == nil {
1523+ return nil // already closed by something else
15241524}
1525- disconnected := make (chan struct {})
1526- a .coordDisconnected = disconnected
15271525defer close (disconnected )
1528- a .closeMutex .Unlock ()
15291526
15301527ctrl := tailnet .NewAgentCoordinationController (a .logger ,network )
15311528coordination := ctrl .New (coordinate )
@@ -1547,6 +1544,17 @@ func (a *agent) runCoordinator(ctx context.Context, tClient tailnetproto.DRPCTai
15471544return <- errCh
15481545}
15491546
1547+ func (a * agent )setCoordDisconnected ()chan struct {} {
1548+ a .closeMutex .Lock ()
1549+ defer a .closeMutex .Unlock ()
1550+ if a .isClosed () {
1551+ return nil
1552+ }
1553+ disconnected := make (chan struct {})
1554+ a .coordDisconnected = disconnected
1555+ return disconnected
1556+ }
1557+
15501558// runDERPMapSubscriber runs a coordinator and returns if a reconnect should occur.
15511559func (a * agent )runDERPMapSubscriber (ctx context.Context ,tClient tailnetproto.DRPCTailnetClient24 ,network * tailnet.Conn )error {
15521560defer a .logger .Debug (ctx ,"disconnected from derp map RPC" )