diff --git a/components/engine/libcontainerd/client_daemon.go b/components/engine/libcontainerd/client_daemon.go
index 60fb3353c1..cb9cb43a73 100644
--- a/components/engine/libcontainerd/client_daemon.go
+++ b/components/engine/libcontainerd/client_daemon.go
@@ -328,6 +328,13 @@ func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin
 	return int(t.Pid()), nil
 }
 
+// Exec creates exec process.
+//
+// The containerd client calls Exec to register the exec config in the shim side.
+// When the client calls Start, the shim will create stdin fifo if needs. But
+// for the container main process, the stdin fifo will be created in Create not
+// the Start call. stdinCloseSync channel should be closed after Start exec
+// process.
 func (c *client) Exec(ctx context.Context, containerID, processID string, spec *specs.Process, withStdin bool, attachStdio StdioCallback) (int, error) {
 	ctr := c.getContainer(containerID)
 	if ctr == nil {
@@ -372,7 +379,9 @@ func (c *client) Exec(ctx context.Context, containerID, processID string, spec *
 	ctr.addProcess(processID, p)
 
 	// Signal c.createIO that it can call CloseIO
-	close(stdinCloseSync)
+	//
+	// the stdin of exec process will be created after p.Start in containerd
+	defer close(stdinCloseSync)
 
 	if err = p.Start(ctx); err != nil {
 		p.Delete(context.Background())