RxRPC: Fix a potential NULL dereference

Fix a potential NULL dereference bug during error handling in
rxrpc_kernel_begin_call(), whereby rxrpc_put_transport() may be handed a NULL
pointer.

This was found with a code checker (http://repo.or.cz/w/smatch.git/).

Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index d7d2bed7a699..eac5e7bb7365 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -284,13 +284,13 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
                 if (IS_ERR(trans)) {
                         call = ERR_CAST(trans);
                         trans = NULL;
-                        goto out;
+                        goto out_notrans;
                 }
         } else {
                 trans = rx->trans;
                 if (!trans) {
                         call = ERR_PTR(-ENOTCONN);
-                        goto out;
+                        goto out_notrans;
                 }
                 atomic_inc(&trans->usage);
         }
@@ -315,6 +315,7 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
         rxrpc_put_bundle(trans, bundle);
 out:
         rxrpc_put_transport(trans);
+out_notrans:
         release_sock(&rx->sk);
         _leave(" = %p", call);
         return call;