SUNRPC: Dequeue the request from the receive queue while we're re-encoding

Ensure that we dequeue the request from the transport receive queue
while we're re-encoding to prevent issues like use-after-free when
we release the bvec.

Fixes: 7536908982047 ("SUNRPC: Ensure the bvecs are reset when we re-encode...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 31 insertions, 23 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 783748dc5e6f..02d5b2125c07 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1324,6 +1324,36 @@ xprt_request_dequeue_transmit(struct rpc_task *task)
 }
 
 /**
+ * xprt_request_dequeue_xprt - remove a task from the transmit+receive queue
+ * @task: pointer to rpc_task
+ *
+ * Remove a task from the transmit and receive queues, and ensure that
+ * it is not pinned by the receive work item.
+ */
+void
+xprt_request_dequeue_xprt(struct rpc_task *task)
+{
+	struct rpc_rqst	*req = task->tk_rqstp;
+	struct rpc_xprt *xprt = req->rq_xprt;
+
+	if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate) ||
+	    test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) ||
+	    xprt_is_pinned_rqst(req)) {
+		spin_lock(&xprt->queue_lock);
+		xprt_request_dequeue_transmit_locked(task);
+		xprt_request_dequeue_receive_locked(task);
+		while (xprt_is_pinned_rqst(req)) {
+			set_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
+			spin_unlock(&xprt->queue_lock);
+			xprt_wait_on_pinned_rqst(req);
+			spin_lock(&xprt->queue_lock);
+			clear_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
+		}
+		spin_unlock(&xprt->queue_lock);
+	}
+}
+
+/**
  * xprt_request_prepare - prepare an encoded request for transport
  * @req: pointer to rpc_rqst
  *
@@ -1754,28 +1784,6 @@ void xprt_retry_reserve(struct rpc_task *task)
 	xprt_do_reserve(xprt, task);
 }
 
-static void
-xprt_request_dequeue_all(struct rpc_task *task, struct rpc_rqst *req)
-{
-	struct rpc_xprt *xprt = req->rq_xprt;
-
-	if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate) ||
-	    test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) ||
-	    xprt_is_pinned_rqst(req)) {
-		spin_lock(&xprt->queue_lock);
-		xprt_request_dequeue_transmit_locked(task);
-		xprt_request_dequeue_receive_locked(task);
-		while (xprt_is_pinned_rqst(req)) {
-			set_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
-			spin_unlock(&xprt->queue_lock);
-			xprt_wait_on_pinned_rqst(req);
-			spin_lock(&xprt->queue_lock);
-			clear_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
-		}
-		spin_unlock(&xprt->queue_lock);
-	}
-}
-
 /**
  * xprt_release - release an RPC request slot
  * @task: task which is finished with the slot
@@ -1795,7 +1803,7 @@ void xprt_release(struct rpc_task *task)
 	}
 
 	xprt = req->rq_xprt;
-	xprt_request_dequeue_all(task, req);
+	xprt_request_dequeue_xprt(task);
 	spin_lock(&xprt->transport_lock);
 	xprt->ops->release_xprt(xprt, task);
 	if (xprt->ops->release_request)