[sync] fix two bugs

api/service/legacysync/syncing.go

@@ -593,7 +593,7 @@ func (ss *StateSync) downloadBlocks(bc *core.BlockChain) {
 					if count > downloadBlocksRetryLimit {
 						break
 					}
-					if err := ss.stateSyncTaskQueue.Put(failedTasks); err != nil {
+					if err := taskQueue.put(failedTasks); err != nil {
 						utils.Logger().Warn().
 							Err(err).
 							Interface("taskIndexes", failedTasks.indexes()).

node/node_syncing.go

@@ -605,7 +605,7 @@ func (node *Node) getEncodedBlockWithSigByHash(hash common.Hash) ([]byte, error)
 
 func (node *Node) getCommitSigAndBitmap(block *types.Block) ([]byte, error) {
 	child := node.Blockchain().GetBlockByNumber(block.NumberU64() + 1)
-	if child == nil {
+	if child != nil {
 		return node.getCommitSigFromChild(block, child)
 	}
 	return node.getCommitSigFromDB(block)