tirpc_clnt_destroy: Determine the return value of clnt_create()

Determine the return value of clnt_create() to avoid segmentation fault
when executing clnt_destroy() when the return value of create is NULL.

Link: https://lore.kernel.org/ltp/[email protected]/
Reviewed-by: Chuck Lever <[email protected]>
Tested-by: Chen Hanxiao <[email protected]>
Reviewed-by: Petr Vorel <[email protected]>
Signed-off-by: Ma Xinjian <[email protected]>

testcases/network/rpc/rpc-tirpc/tests_pack/rpc_suite/tirpc/tirpc_toplevel_clnt_destroy/tirpc_clnt_destroy.c

@@ -58,6 +58,13 @@ int main(int argn, char *argc[])
 	//first create client
 	clnt = clnt_create(argc[1], progNum, VERSNUM, nettype);
 
+	if (clnt == NULL) {
+		clnt_pcreateerror("err");
+		printf("%d\n", rpc_createerr.cf_stat);
+
+		return 1;
+	}
+
 	//then call destroy macro
 	clnt_destroy(clnt);