diff --git a/usr.bin/su/su.c b/usr.bin/su/su.c
index 76f76b61e64d..26f4a3ef9209 100644
--- a/usr.bin/su/su.c
+++ b/usr.bin/su/su.c
@@ -567,8 +567,9 @@ export_pam_environment(void)
 
 	for (pp = environ_pam; *pp != NULL; pp++) {
 		if (ok_to_export(*pp))
-			putenv(*pp);
-		free(*pp);
+			(void)putenv(*pp);
+		else
+			free(*pp);
 	}
 }