fix #304

Signed-off-by: NH-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
@@ -237,9 +238,10 @@ int taosInitTimer(void *(*callback)(void *), int ms) {
         return -1;
     }
 
-  int *tms = (int *)malloc(sizeof(int));
+    int *tms = (int *) malloc(sizeof(int));
     *tms = ms;
-  if (pthread_create(&thread, &tattr, callback, (void *)tms)) {
+    if (pthread_create(&thread, &tattr, callback, (void *) tms)) {
+        free(tms);
         return -1;
     }