fix #304

Signed-off-by: H-ZeX <hzx20112012@gmail.com>

src/os/linux/src/os.c

@@ -223,6 +223,7 @@ int taosOpenUDServerSocket(char *ip, short port) {
   return sockFd;
 }
 
+// The callback functions MUST free the param pass to it after finishing use it.
 int taosInitTimer(void *(*callback)(void *), int ms) {
     /********************************************************
      * Create SIGALRM loop thread
@@ -240,6 +241,7 @@ int taosInitTimer(void *(*callback)(void *), int ms) {
     int *tms = (int *) malloc(sizeof(int));
     *tms = ms;
     if (pthread_create(&thread, &tattr, callback, (void *) tms)) {
+        free(tms);
         return -1;
     }