On Tue, 19 Jun 2012 20:47:04 +0200, Jean Delvare wrote:

On Fri,  6 Jan 2012 18:58:21 +0800, Daniel Kurtz wrote:

quoted

@@ -879,8 +953,24 @@ static int __devinit i801_probe(struct pci_dev *dev,
 	i801_probe_optional_slaves(priv);
 
 	pci_set_drvdata(dev, priv);
+
+	if (priv->features & FEATURE_IRQ) {
+		init_waitqueue_head(&priv->waitq);
+		spin_lock_init(&priv->lock);
+
+		err = request_irq(dev->irq, i801_isr, IRQF_SHARED,
+				  i801_driver.name, priv);
+		if (err) {
+			dev_err(&dev->dev, "Failed to allocate irq %d: %d",

Missing "\n".

quoted

+				dev->irq, err);
+			goto exit_del_adapter;
+		}

I believe order is wrong, and interrupt handler should be installed
_before_ registering the adapter. Otherwise you have a race condition
where the handler could be called before the waitqueue and spinlock are
initialized.

Oh, and it's not a theoretical thing. I can reproducibly crash the
kernel by removing and loading the i2c-i801 driver again. Swapping
request_irq() and i2c_add_adapter() solves it.

-- 
Jean Delvare