--- x/drivers/comedi/comedi_fops.c
+++ y/drivers/comedi/comedi_fops.c
@@ -2454,7 +2454,7 @@ static __poll_t comedi_poll(struct file
 	struct comedi_device *dev = cfp->dev;
 	struct comedi_subdevice *s, *s_read;
 
-	down_read(&dev->attach_lock);
+	down_write(&dev->attach_lock);
 
 	if (!dev->attached) {
 		dev_dbg(dev->class_dev, "no driver attached\n");
@@ -2484,7 +2484,7 @@ static __poll_t comedi_poll(struct file
 	}
 
 done:
-	up_read(&dev->attach_lock);
+	up_write(&dev->attach_lock);
 	return mask;
 }