1 files changed, 20 insertions, 2 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 2b720fa35c4f..e18500151236 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -421,6 +421,9 @@ static void svc_data_ready(struct sock *sk)
                 dprintk("svc: socket %p(inet %p), busy=%d\n",
                         svsk, sk,
                         test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
+
+                /* Refer to svc_setup_socket() for details. */
+                rmb();
                 svsk->sk_odata(sk);
                 if (!test_and_set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags))
                         svc_xprt_enqueue(&svsk->sk_xprt);
@@ -437,6 +440,9 @@ static void svc_write_space(struct sock *sk)
         if (svsk) {
                 dprintk("svc: socket %p(inet %p), write_space busy=%d\n",
                         svsk, sk, test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
+
+                /* Refer to svc_setup_socket() for details. */
+                rmb();
                 svsk->sk_owspace(sk);
                 svc_xprt_enqueue(&svsk->sk_xprt);
         }
@@ -760,8 +766,12 @@ static void svc_tcp_listen_data_ready(struct sock *sk)
         dprintk("svc: socket %p TCP (listen) state change %d\n",
                 sk, sk->sk_state);
 
-        if (svsk)
+        if (svsk) {
+                /* Refer to svc_setup_socket() for details. */
+                rmb();
                 svsk->sk_odata(sk);
+        }
+
         /*
          * This callback may called twice when a new connection
          * is established as a child socket inherits everything
@@ -794,6 +804,8 @@ static void svc_tcp_state_change(struct sock *sk)
         if (!svsk)
                 printk("svc: socket %p: no user data\n", sk);
         else {
+                /* Refer to svc_setup_socket() for details. */
+                rmb();
                 svsk->sk_ostate(sk);
                 if (sk->sk_state != TCP_ESTABLISHED) {
                         set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
@@ -1381,12 +1393,18 @@ static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
                 return ERR_PTR(err);
         }
 
-        inet->sk_user_data = svsk;
         svsk->sk_sock = sock;
         svsk->sk_sk = inet;
         svsk->sk_ostate = inet->sk_state_change;
         svsk->sk_odata = inet->sk_data_ready;
         svsk->sk_owspace = inet->sk_write_space;
+        /*
+         * This barrier is necessary in order to prevent race condition
+         * with svc_data_ready(), svc_listen_data_ready() and others
+         * when calling callbacks above.
+         */
+        wmb();
+        inet->sk_user_data = svsk;
 
         /* Initialize the socket */
         if (sock->type == SOCK_DGRAM)