diff --git a/qtfs/rexec/rexec_shim.c b/qtfs/rexec/rexec_shim.c
index 241db074f074862b40298f491dea1e2922535d46..0394ba91dc9857f8d8b14d027eece071e362ffde 100644
--- a/qtfs/rexec/rexec_shim.c
+++ b/qtfs/rexec/rexec_shim.c
@@ -227,18 +227,19 @@ int rexec_shim_entry(int argc, char *argv[])
 	char **newarg = NULL;
 
 	if (strcmp(argv[0], "-f") == 0) {
+		rshim_log("Get json str:%s", json_str);
 		json_str = argv[1];
 		newarg = &argv[2];
 	} else {
 		newarg = argv;
 	}
 
-	rshim_log("Get json str:%s", json_str);
 	rshim_close_all_fd();
-
-	rshim_reg_file_resume(json_str);
-	rexec_log_son_rebuild();
-	rshim_process_attr_resume(json_str);
+	if(json_str != NULL){
+		rshim_reg_file_resume(json_str);
+		rexec_log_son_rebuild();
+		rshim_process_attr_resume(json_str);
+	}
 	execvp(newarg[0], newarg);
 	perror("execvp failed.");