SUNRPC: Handle allocation failure in rpc_new_task()

If the call to rpc_alloc_task() fails, then ensure that the calldata is
released, and that rpc_run_task() and rpc_run_bc_task() bail out early.
Reported-by: NeilBrown <neilb@suse.de>
Fixes: 910ad386 ("NFS: Fix memory allocation in rpc_alloc_task()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

net/sunrpc/clnt.c

@@ -1127,6 +1127,8 @@ struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 	struct rpc_task *task;
 
 	task = rpc_new_task(task_setup_data);
+	if (IS_ERR(task))
+		return task;
 
 	if (!RPC_IS_ASYNC(task))
 		task->tk_flags |= RPC_TASK_CRED_NOREF;
@@ -1227,6 +1229,11 @@ struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
 	 * Create an rpc_task to send the data
 	 */
 	task = rpc_new_task(&task_setup_data);
+	if (IS_ERR(task)) {
+		xprt_free_bc_request(req);
+		return task;
+	}
+
 	xprt_init_bc_request(req, task);
 
 	task->tk_action = call_bc_encode;

net/sunrpc/sched.c

@@ -1128,6 +1128,11 @@ struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
 
 	if (task == NULL) {
 		task = rpc_alloc_task();
+		if (task == NULL) {
+			rpc_release_calldata(setup_data->callback_ops,
+					     setup_data->callback_data);
+			return ERR_PTR(-ENOMEM);
+		}
 		flags = RPC_TASK_DYNAMIC;
 	}