diff --git a/src/arg.c b/src/arg.c
index 1bf6444d3..e7bed1ed9 100644
--- a/src/arg.c
+++ b/src/arg.c
@@ -290,6 +290,7 @@ int make_arg_list(const char *in, int len, unsigned int mask, struct arg **argp,
  err:
 	free(word);
 	free(*argp);
+	*argp = NULL;
 	if (err_arg)
 		*err_arg = pos;
 	if (err_ptr)