v3rpc: lock progress and prevKV map correctly

etcdserver/api/v3rpc/watch.go

@@ -86,11 +86,11 @@ type serverWatchStream struct {
 	watchStream mvcc.WatchStream
 	ctrlStream  chan *pb.WatchResponse
 
+	// mu protects progress, prevKV
+	mu sync.Mutex
 	// progress tracks the watchID that stream might need to send
 	// progress to.
 	progress map[mvcc.WatchID]bool
-	// mu protects progress
-	mu sync.Mutex
 
 	// closec indicates the stream is closed.
 	closec chan struct{}
@@ -171,7 +171,9 @@ func (sws *serverWatchStream) recvLoop() error {
 			}
 			id := sws.watchStream.Watch(creq.Key, creq.RangeEnd, rev)
 			if id != -1 && creq.ProgressNotify {
+				sws.mu.Lock()
 				sws.progress[id] = true
+				sws.mu.Unlock()
 			}
 			wr := &pb.WatchResponse{
 				Header:   sws.newResponseHeader(wsrev),
@@ -298,12 +300,14 @@ func (sws *serverWatchStream) sendLoop() {
 				delete(pending, wid)
 			}
 		case <-progressTicker.C:
+			sws.mu.Lock()
 			for id, ok := range sws.progress {
 				if ok {
 					sws.watchStream.RequestProgress(id)
 				}
 				sws.progress[id] = true
 			}
+			sws.mu.Unlock()
 		case <-sws.closec:
 			return
 		}