rxrpc: Don't release call mutex on error pointer

Don't release call mutex at the end of rxrpc_kernel_begin_call() if the
call pointer actually holds an error value.

Fixes: 540b1c48c37a ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Reported-by: Marc Dionne <marc.dionne@auristor.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 fb17552fd292..4b0a8288c98a 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -308,10 +308,11 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
         call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, tx_total_len,
                                      gfp);
         /* The socket has been unlocked. */
-        if (!IS_ERR(call))
+        if (!IS_ERR(call)) {
                 call->notify_rx = notify_rx;
+                mutex_unlock(&call->user_mutex);
+        }
 
-        mutex_unlock(&call->user_mutex);
         _leave(" = %p", call);
         return call;
 }