bridge: per vlan dst_metadata netlink support

Hello Roopa Prabhu,

This is a semi-automatic email about new static checker warnings.

The patch efa5356b0d97: "bridge: per vlan dst_metadata netlink support" from Jan 31, 2017, leads to the following Smatch complaint:

net/bridge/br_netlink_tunnel.c:144 br_fill_vlan_tinfo_range()
error: we previously assumed 'vtbegin' could be null (see line 130)

net/bridge/br_netlink_tunnel.c
129

   130		if (vtbegin && vtend && (vtend->vid - vtbegin->vid) > 0) {
                    ^^^^^^^

Check for NULL.

131 /* add range to skb */
132 err = br_fill_vlan_tinfo(skb, vtbegin->vid,
133 vtbegin->tinfo.tunnel_id,
134 BRIDGE_VLAN_INFO_RANGE_BEGIN);
135 if (err)
136 return err;
137
138 err = br_fill_vlan_tinfo(skb, vtend->vid,
139 vtend->tinfo.tunnel_id,
140 BRIDGE_VLAN_INFO_RANGE_END);
141 if (err)
142 return err;
143 } else {
144 err = br_fill_vlan_tinfo(skb, vtbegin->vid,

                                                      ^^^^^^^^^^^^

Unchecked dereference.

145 vtbegin->tinfo.tunnel_id,
146 0);

regards,
dan carpenter