SUNRPC: Fix an Oops in udp_poll()

udp_poll() checks the struct file for the O_NONBLOCK flag, so we must not
call it with a NULL file pointer.

Fixes: 0ffe86f48026 ("SUNRPC: Use poll() to fix up the socket requeue races")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

2 files changed, 20 insertions, 2 deletions

diff --git a/include/linux/sunrpc/xprtsock.h b/include/linux/sunrpc/xprtsock.h
index 458bfe0137f5..b81d0b3e0799 100644
--- a/include/linux/sunrpc/xprtsock.h
+++ b/include/linux/sunrpc/xprtsock.h
@@ -26,6 +26,7 @@ struct sock_xprt {
          */
         struct socket *         sock;
         struct sock *           inet;
+        struct file *           file;
 
         /*
          * State of TCP reply receive
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 53de72d2dded..e829036ed81f 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -670,7 +670,8 @@ out_err:
 
 static __poll_t xs_poll_socket(struct sock_xprt *transport)
 {
-        return transport->sock->ops->poll(NULL, transport->sock, NULL);
+        return transport->sock->ops->poll(transport->file, transport->sock,
+                        NULL);
 }
 
 static bool xs_poll_socket_readable(struct sock_xprt *transport)
@@ -1253,6 +1254,7 @@ static void xs_reset_transport(struct sock_xprt *transport)
         struct socket *sock = transport->sock;
         struct sock *sk = transport->inet;
         struct rpc_xprt *xprt = &transport->xprt;
+        struct file *filp = transport->file;
 
         if (sk == NULL)
                 return;
@@ -1266,6 +1268,7 @@ static void xs_reset_transport(struct sock_xprt *transport)
         write_lock_bh(&sk->sk_callback_lock);
         transport->inet = NULL;
         transport->sock = NULL;
+        transport->file = NULL;
 
         sk->sk_user_data = NULL;
 
@@ -1278,7 +1281,7 @@ static void xs_reset_transport(struct sock_xprt *transport)
         mutex_unlock(&transport->recv_mutex);
 
         trace_rpc_socket_close(xprt, sock);
-        sock_release(sock);
+        fput(filp);
 
         xprt_disconnect_done(xprt);
 }
@@ -1873,6 +1876,7 @@ static struct socket *xs_create_sock(struct rpc_xprt *xprt,
                 struct sock_xprt *transport, int family, int type,
                 int protocol, bool reuseport)
 {
+        struct file *filp;
         struct socket *sock;
         int err;
 
@@ -1893,6 +1897,11 @@ static struct socket *xs_create_sock(struct rpc_xprt *xprt,
                 goto out;
         }
 
+        filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+        if (IS_ERR(filp))
+                return ERR_CAST(filp);
+        transport->file = filp;
+
         return sock;
 out:
         return ERR_PTR(err);
@@ -1938,6 +1947,7 @@ static int xs_local_finish_connecting(struct rpc_xprt *xprt,
 static int xs_local_setup_socket(struct sock_xprt *transport)
 {
         struct rpc_xprt *xprt = &transport->xprt;
+        struct file *filp;
         struct socket *sock;
         int status = -EIO;
 
@@ -1950,6 +1960,13 @@ static int xs_local_setup_socket(struct sock_xprt *transport)
         }
         xs_reclassify_socket(AF_LOCAL, sock);
 
+        filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
+        if (IS_ERR(filp)) {
+                status = PTR_ERR(filp);
+                goto out;
+        }
+        transport->file = filp;
+
         dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
                         xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);