diff --git a/drivers/staging/most/cdev/cdev.c b/drivers/staging/most/cdev/cdev.c
index 8e7652545402..4569838f27a0 100644
--- a/drivers/staging/most/cdev/cdev.c
+++ b/drivers/staging/most/cdev/cdev.c
@@ -292,13 +292,15 @@ static __poll_t comp_poll(struct file *filp, poll_table *wait)
 
 	poll_wait(filp, &c->wq, wait);
 
+	mutex_lock(&c->io_mutex);
 	if (c->cfg->direction == MOST_CH_RX) {
-		if (!kfifo_is_empty(&c->fifo))
+		if (!c->dev || !kfifo_is_empty(&c->fifo))
 			mask |= EPOLLIN | EPOLLRDNORM;
 	} else {
-		if (!kfifo_is_empty(&c->fifo) || ch_has_mbo(c))
+		if (!c->dev || !kfifo_is_empty(&c->fifo) || ch_has_mbo(c))
 			mask |= EPOLLOUT | EPOLLWRNORM;
 	}
+	mutex_unlock(&c->io_mutex);
 	return mask;
 }