SUNRPC: Prevent races in xs_abort_connection()

The call to xprt_disconnect_done() that is triggered by a successful
connection reset will trigger another automatic wakeup of all tasks
on the xprt->pending rpc_wait_queue. In particular it will cause an
early wake up of the task that called xprt_connect().

All we really want to do here is clear all the socket-specific state
flags, so we split that functionality out of xs_sock_mark_closed()
into a helper that can be called by xs_abort_connection()

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 7e2dd0d69f1b..1f105c2d2e15 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1453,7 +1453,7 @@ static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
         xprt_clear_connecting(xprt);
 }
 
-static void xs_sock_mark_closed(struct rpc_xprt *xprt)
+static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
 {
         smp_mb__before_clear_bit();
         clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
@@ -1461,6 +1461,11 @@ static void xs_sock_mark_closed(struct rpc_xprt *xprt)
         clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
         clear_bit(XPRT_CLOSING, &xprt->state);
         smp_mb__after_clear_bit();
+}
+
+static void xs_sock_mark_closed(struct rpc_xprt *xprt)
+{
+        xs_sock_reset_connection_flags(xprt);
         /* Mark transport as closed and wake up all pending tasks */
         xprt_disconnect_done(xprt);
 }
@@ -2051,10 +2056,8 @@ static void xs_abort_connection(struct sock_xprt *transport)
         any.sa_family = AF_UNSPEC;
         result = kernel_connect(transport->sock, &any, sizeof(any), 0);
         if (!result)
-                xs_sock_mark_closed(&transport->xprt);
-        else
-                dprintk("RPC:       AF_UNSPEC connect return code %d\n",
-                                result);
+                xs_sock_reset_connection_flags(&transport->xprt);
+        dprintk("RPC:       AF_UNSPEC connect return code %d\n", result);
 }
 
 static void xs_tcp_reuse_connection(struct sock_xprt *transport)