fix: crash if db not exist while process status msg

source/dnode/mnode/impl/src/mndDnode.c

@@ -389,7 +389,7 @@ static int32_t mndProcessStatusReq(SRpcMsg *pReq) {
       }
       if (roleChanged) {
         SDbObj *pDb = mndAcquireDb(pMnode, pVgroup->dbName);
-        if (pDb->stateTs != curMs) {
+        if (pDb != NULL && pDb->stateTs != curMs) {
           mInfo("db:%s, stateTs changed by status msg, old stateTs:%" PRId64 " new stateTs:%" PRId64, pDb->name, pDb->stateTs, curMs);
           pDb->stateTs = curMs;
         }

source/dnode/mnode/impl/src/mndMain.c

@@ -164,7 +164,7 @@ static void mndSetVgroupOffline(SMnode *pMnode, int32_t dnodeId, int64_t curMs)
 
     if (roleChanged) {
       SDbObj *pDb = mndAcquireDb(pMnode, pVgroup->dbName);
-      if (pDb->stateTs != curMs) {
+      if (pDb != NULL && pDb->stateTs != curMs) {
         mInfo("db:%s, stateTs changed by offline check, old newTs:%" PRId64 " newTs:%" PRId64, pDb->name, pDb->stateTs,
               curMs);
         pDb->stateTs = curMs;