tipc: fix connection refcount leak

[ Upstream commit 4652edb70e8a7eebbe47fa931940f65522c36e8f ]

When tipc_conn_sendmsg() calls tipc_conn_lookup() to query a
connection instance, its reference count value is increased if
it's found. But subsequently if it's found that the connection is
closed, the work of sending message is not queued into its server
send workqueue, and the connection reference count is not decreased.
This will cause a reference count leak. To reproduce this problem,
an application would need to open and closes topology server
connections with high intensity.

We fix this by immediately decrementing the connection reference
count if a send fails due to the connection being closed.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/net/tipc/server.c b/net/tipc/server.c
index ae474479f12e86fc59564c82f773cc28e9c9d9a6..bd2336aad0e45bfa53c141e19a3c7ecfb124cb18 100644 (file)
--- a/net/tipc/server.c
+++ b/net/tipc/server.c
@@ -427,10 +427,12 @@ int tipc_conn_sendmsg(struct tipc_server *s, int conid,
        list_add_tail(&e->list, &con->outqueue);
        spin_unlock_bh(&con->outqueue_lock);
 
-       if (test_bit(CF_CONNECTED, &con->flags))
+       if (test_bit(CF_CONNECTED, &con->flags)) {
                if (!queue_work(s->send_wq, &con->swork))
                        conn_put(con);
-
+       } else {
+               conn_put(con);
+       }
        return 0;
 }