tipc: tipc clang warning

BugLink: https://bugs.launchpad.net/bugs/1863019
[ Upstream commit 737889efe9713a0f20a75fd0de952841d9275e6b ]

When checking the code with clang -Wsometimes-uninitialized we get the
following warning:

if (!tipc_link_is_establishing(l)) {
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/tipc/node.c:847:46: note: uninitialized use occurs here
      tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);

net/tipc/node.c:831:2: note: remove the 'if' if its condition is always
true
if (!tipc_link_is_establishing(l)) {
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/tipc/node.c:821:31: note: initialize the variable 'maddr' to silence
this warning
struct tipc_media_addr *maddr;

We fix this by initializing 'maddr' to NULL. For the matter of clarity,
we also test if 'xmitq' is non-empty before we use it and 'maddr'
further down in the  function. It will never happen that 'xmitq' is non-
empty at the same time as 'maddr' is NULL, so this is a sufficient test.

Fixes: 598411d70f85 ("tipc: make resetting of links non-atomic")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/net/tipc/node.c b/net/tipc/node.c
index fdc2bbbbfa40b3bd4a2a257fe53427aa8008e2dd..da993dab14351acae5052f989371de2617acc155 100644 (file)
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -694,10 +694,10 @@ static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
 static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
 {
        struct tipc_link_entry *le = &n->links[bearer_id];
+       struct tipc_media_addr *maddr = NULL;
        struct tipc_link *l = le->link;
-       struct tipc_media_addr *maddr;
-       struct sk_buff_head xmitq;
        int old_bearer_id = bearer_id;
+       struct sk_buff_head xmitq;
 
        if (!l)
                return;
@@ -719,7 +719,8 @@ static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
        tipc_node_write_unlock(n);
        if (delete)
                tipc_mon_remove_peer(n->net, n->addr, old_bearer_id);
-       tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
+       if (!skb_queue_empty(&xmitq))
+               tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
        tipc_sk_rcv(n->net, &le->inputq);
 }