unknown reason cause ticket's storage broken with illegal key

I'm not sure if add lock can solve this problem.
It's hard to reproduce the bug,
may be need more chain split and call fsn.allTickets() in api frequently

core/state/statedb.go

@@ -81,7 +81,8 @@ type StateDB struct {
 	validRevisions []revision
 	nextRevisionId int
 
-	lock sync.Mutex
+	lock   sync.Mutex
+	rwlock sync.RWMutex
 }
 
 // Create a new state from a given trie.
@@ -951,6 +952,9 @@ func (db *StateDB) UpdateAsset(asset common.Asset) error {
 func (db *StateDB) setTicketState(key, value common.Hash) {
 	stateObject := db.GetOrNewStateObject(common.TicketKeyAddress)
 	if stateObject != nil {
+		db.rwlock.Lock()
+		defer db.rwlock.Unlock()
+
 		stateObject.SetState(db.db, key, value)
 	}
 }
@@ -965,6 +969,9 @@ func (db *StateDB) IsTicketExist(id common.Hash) bool {
 func (db *StateDB) GetTicket(id common.Hash) (*common.Ticket, error) {
 	stateObject := db.getStateObject(common.TicketKeyAddress)
 	if stateObject != nil && id != (common.Hash{}) {
+		db.rwlock.RLock()
+		defer db.rwlock.RUnlock()
+
 		value := stateObject.GetState(db.db, id)
 		ticket, err := common.ParseTicket(id, value)
 		if err == nil {
@@ -976,6 +983,9 @@ func (db *StateDB) GetTicket(id common.Hash) (*common.Ticket, error) {
 
 // AllTickets wacom
 func (db *StateDB) AllTickets() (common.TicketSlice, error) {
+	db.rwlock.RLock()
+	defer db.rwlock.RUnlock()
+
 	stateObject := db.getStateObject(common.TicketKeyAddress)
 	if stateObject == nil {
 		return nil, nil