diff --git a/src/balance/src/balance.c b/src/balance/src/balance.c
index 0d2d9fc778b437b8fe0671487da097f6c531b204..2b1888042c0645a93ae08fe9438085f96e547b71 100644
--- a/src/balance/src/balance.c
+++ b/src/balance/src/balance.c
@@ -165,7 +165,7 @@ int32_t balanceAllocVnodes(SVgObj *pVgroup) {
       balanceSwapVnodeGid(pVgroup->vnodeGid, pVgroup->vnodeGid + 1);
     }
   } else {
-    int32_t randVal = rand() % 6;
+    int32_t randVal = randIndex++ % 6;
     if (randVal == 1) {  // 1, 0, 2
       balanceSwapVnodeGid(pVgroup->vnodeGid + 0, pVgroup->vnodeGid + 1);
     } else if (randVal == 2) {  // 1, 2, 0
diff --git a/src/plugins/mqtt/src/mqttSystem.c b/src/plugins/mqtt/src/mqttSystem.c
index ab3f3f5d841bbfd5c2c2f7cd439c445ccaae93b2..b64c4715e898ce1eeeba430bc43a810070a33bc5 100644
--- a/src/plugins/mqtt/src/mqttSystem.c
+++ b/src/plugins/mqtt/src/mqttSystem.c
@@ -47,7 +47,11 @@ int32_t mqttInitSystem() {
   recntStatus.recvbufsz = sizeof(recvbuf);
   char* url = tsMqttBrokerAddress;
   recntStatus.user_name = strstr(url, "@") != NULL ? strbetween(url, "//", ":") : NULL;
-  recntStatus.password = strstr(url, "@") != NULL ? strbetween(strstr(url, recntStatus.user_name), ":", "@") : NULL;
+  
+  char * passStr = strstr(url, recntStatus.user_name);
+  if (passStr != NULL) {
+    recntStatus.password = strstr(url, "@") != NULL ? strbetween(passStr, ":", "@") : NULL;
+  }
 
   if (strlen(url) == 0) {
     mqttDebug("mqtt module not init, url is null");
diff --git a/src/util/src/tsocket.c b/src/util/src/tsocket.c
index 23f2e5f00ae339937a9812ca0deab901275e6a89..94e6d0e4e15be77a8341d15e72d892f6022209df 100644
--- a/src/util/src/tsocket.c
+++ b/src/util/src/tsocket.c
@@ -231,7 +231,7 @@ SOCKET taosOpenUdpSocket(uint32_t ip, uint16_t port) {
   localAddr.sin_addr.s_addr = ip;
   localAddr.sin_port = (uint16_t)htons(port);
 
-  if ((sockFd = (int)socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+  if ((sockFd = (int)socket(AF_INET, SOCK_DGRAM, 0)) <= 2) {
     uError("failed to open udp socket: %d (%s)", errno, strerror(errno));
     return -1;
   }
@@ -265,7 +265,7 @@ SOCKET taosOpenTcpClientSocket(uint32_t destIp, uint16_t destPort, uint32_t clie
 
   sockFd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
 
-  if (sockFd < 0) {
+  if (sockFd <= 2) {
     uError("failed to open the socket: %d (%s)", errno, strerror(errno));
     return -1;
   }
@@ -276,7 +276,7 @@ SOCKET taosOpenTcpClientSocket(uint32_t destIp, uint16_t destPort, uint32_t clie
     uError("setsockopt SO_REUSEADDR failed: %d (%s)", errno, strerror(errno));
     taosCloseSocket(sockFd);
     return -1;
-  };
+  }
 
   if (clientIp != 0) {
     memset((char *)&clientAddr, 0, sizeof(clientAddr));
@@ -371,7 +371,7 @@ SOCKET taosOpenTcpServerSocket(uint32_t ip, uint16_t port) {
   serverAdd.sin_addr.s_addr = ip;
   serverAdd.sin_port = (uint16_t)htons(port);
 
-  if ((sockFd = (int)socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 2) {
+  if ((sockFd = (int)socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) <= 2) {
     uError("failed to open TCP socket: %d (%s)", errno, strerror(errno));
     return -1;
   }