deadlock

balancer_conn_wrappers.go

@@ -82,16 +82,21 @@ func (ccb *ccBalancerWrapper) watcher() {
 		}
 
 		if ccb.closed.HasFired() {
+			ccb.balancerMu.Lock()
 			ccb.balancer.Close()
+			ccb.balancerMu.Unlock()
 			ccb.mu.Lock()
 			scs := ccb.subConns
 			ccb.subConns = nil
 			ccb.mu.Unlock()
+			ccb.UpdateState(balancer.State{ConnectivityState: connectivity.Connecting, Picker: nil})
+			ccb.done.Fire()
+			// Fire done before removing the addr conns.  We can safely unblock
+			// ccb.close and allow the removeAddrConns to happen
+			// asynchronously.
 			for acbw := range scs {
 				ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
 			}
-			ccb.UpdateState(balancer.State{ConnectivityState: connectivity.Connecting, Picker: nil})
-			ccb.done.Fire()
 			return
 		}
 	}