diff --git a/drivers/comedi/drivers/das6402.c b/drivers/comedi/drivers/das6402.c
index 516a5d5a2840..384e9ba8d5df 100644
--- a/drivers/comedi/drivers/das6402.c
+++ b/drivers/comedi/drivers/das6402.c
@@ -173,10 +173,16 @@ static irqreturn_t das6402_interrupt(int irq, void *d)
 {
 	struct comedi_device *dev = d;
 	struct comedi_subdevice *s = dev->read_subdev;
-	struct comedi_async *async = s->async;
-	struct comedi_cmd *cmd = &async->cmd;
+	struct comedi_async *async;
+	struct comedi_cmd *cmd;
 	unsigned int status;
 
+	if (!dev->attached)
+		return IRQ_NONE;
+
+	async = s->async;
+	cmd = &async->cmd;
+
 	status = inb(dev->iobase + DAS6402_STATUS_REG);
 	if ((status & DAS6402_STATUS_INT) == 0)
 		return IRQ_NONE;