Hello Sven Eckelmann,

The patch 011c935fceae: "batman-adv: Ignore invalid batadv_v_gw during netlink send" from Feb 19, 2018, leads to the following static checker warning:

net/batman-adv/bat_iv_ogm.c:2745 batadv_iv_gw_dump_entry() warn: missing error code here? 'batadv_neigh_ifinfo_get()' failed. 'ret' = '0'

net/batman-adv/bat_iv_ogm.c 2719 /** 2720 * batadv_iv_gw_dump_entry() - Dump a gateway into a message 2721 * @msg: Netlink message to dump into 2722 * @portid: Port making netlink request 2723 * @seq: Sequence number of netlink message 2724 * @bat_priv: The bat priv with all the soft interface information 2725 * @gw_node: Gateway to be dumped 2726 * 2727 * Return: Error code, or 0 on success ^^^^^^^^^^^^^^^^^^^^^^^^^^^ This is sort of out of date.

2728 */ 2729 static int batadv_iv_gw_dump_entry(struct sk_buff *msg, u32 portid, u32 seq, 2730 struct batadv_priv *bat_priv, 2731 struct batadv_gw_node *gw_node) 2732 { 2733 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 2734 struct batadv_neigh_node *router; 2735 struct batadv_gw_node *curr_gw; 2736 int ret = 0; 2737 void *hdr; 2738 2739 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT); 2740 if (!router) 2741 goto out; ^^^^^^^^ 2742 2743 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); 2744 if (!router_ifinfo) 2745 goto out; ^^^^^^^^

These two were obviously changed from -EINVAL to 0 intentionally, but it causes a static checker warning. What really helps me when I'm reviewing error codes is if they're explicit:

if (!router_ifinfo) { ret = 0; goto out; }

2746 2747 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 2748 2749 hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family, 2750 NLM_F_MULTI, BATADV_CMD_GET_GATEWAYS); 2751 if (!hdr) { 2752 ret = -ENOBUFS; ^^^^^^^^^^^^^^ The commit message sort of implies that only -EMSGSIZE and 0 are valid returns but -ENOBUFS is also valid.

2753 goto out; 2754 } 2755 2756 ret = -EMSGSIZE; ^^^^^^^^^^^^^^^ 2757 2758 if (curr_gw == gw_node) 2759 if (nla_put_flag(msg, BATADV_ATTR_FLAG_BEST)) { 2760 genlmsg_cancel(msg, hdr); 2761 goto out; 2762 } 2763

Anyway, the code seems fine and I've marked it as a false positive so it doesn't really require any action from you. I just wanted you to know my thinking here.

regards, dan carpenter