netfilter: nfnetlink_queue: avoid harmless unnitialized variable warnings

Several ARM default configurations give us warnings on recent
compilers about potentially uninitialized variables in the
nfnetlink code in two functions:

net/netfilter/nfnetlink_queue.c: In function 'nfqnl_build_packet_message':
net/netfilter/nfnetlink_queue.c:519:19: warning: 'nfnl_ct' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0)

Moving the rcu_dereference(nfnl_ct_hook) call outside of the
conditional code avoids the warning without forcing us to
preinitialize the variable.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: a4b4766c3ceb ("netfilter: nfnetlink_queue: rename related to nfqueue attaching conntrack info")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 7d81d280cb4ff3e8878af96bd644930f68a4340c..3e240544f34682852dabb1c5058e620aecf539a7 100644 (file)
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -365,8 +365,9 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
                break;
        }
 
+       nfnl_ct = rcu_dereference(nfnl_ct_hook);
+
        if (queue->flags & NFQA_CFG_F_CONNTRACK) {
-               nfnl_ct = rcu_dereference(nfnl_ct_hook);
                if (nfnl_ct != NULL) {
                        ct = nfnl_ct->get_ct(entskb, &ctinfo);
                        if (ct != NULL)
@@ -1064,9 +1065,10 @@ nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
        if (entry == NULL)
                return -ENOENT;
 
+       /* rcu lock already held from nfnl->call_rcu. */
+       nfnl_ct = rcu_dereference(nfnl_ct_hook);
+
        if (nfqa[NFQA_CT]) {
-               /* rcu lock already held from nfnl->call_rcu. */
-               nfnl_ct = rcu_dereference(nfnl_ct_hook);
                if (nfnl_ct != NULL)
                        ct = nfqnl_ct_parse(nfnl_ct, nlh, nfqa, entry, &ctinfo);
        }