Re: [patch]missing error check in probing

[Oliver Neukum <oliver@xxxxxxxxxx>]

Am Donnerstag, 27. August 2009 04:25:49 schrieb Alan Stern:
> On Thu, 27 Aug 2009, Oliver Neukum wrote:
> > If usb_set_interface() needs to be called during probing, it
> > may return an error which needs to be checked for.
>
> You didn't add a comparable check to usb_unbind_interface().  If the
> usb_set_interface() call in there fails, you should set
> intf->needs_altsetting0.

Indeedd.

	Regards
		Oliver

Signed-off-by: Oliver Neukum <oliver@xxxxxxxxxx>

--

commit 25fc22f503ffc9e93eb339cb5fa1dc18d7cc2c7a
Author: Oliver Neukum <oliver@xxxxxxxxxx>
Date:   Thu Aug 27 15:54:13 2009 +0200

    usb: check for IO errors usb_set_interface can return
    
    if they happen while unbinding a flag is set to retry upon probe
    if they happen during probe they are handled as probe errors

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 69e5773..9d8bc8c 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -236,24 +236,30 @@ static int usb_probe_interface(struct device *dev)
 
 		/* Carry out a deferred switch to altsetting 0 */
 		if (intf->needs_altsetting0) {
-			usb_set_interface(udev, intf->altsetting[0].
+			error = usb_set_interface(udev, intf->altsetting[0].
 					desc.bInterfaceNumber, 0);
+			if (error < 0)
+				goto err;
+
 			intf->needs_altsetting0 = 0;
 		}
 
 		error = driver->probe(intf, id);
-		if (error) {
-			mark_quiesced(intf);
-			intf->needs_remote_wakeup = 0;
-			intf->condition = USB_INTERFACE_UNBOUND;
-			usb_cancel_queued_reset(intf);
-		} else
-			intf->condition = USB_INTERFACE_BOUND;
+		if (error)
+			goto err;
 
+		intf->condition = USB_INTERFACE_BOUND;
 		usb_autosuspend_device(udev);
 	}
 
 	return error;
+
+err:
+	mark_quiesced(intf);
+	intf->needs_remote_wakeup = 0;
+	intf->condition = USB_INTERFACE_UNBOUND;
+	usb_cancel_queued_reset(intf);
+	return error;
 }
 
 /* called from driver core with dev locked */
@@ -262,7 +268,7 @@ static int usb_unbind_interface(struct device *dev)
 	struct usb_driver *driver = to_usb_driver(dev->driver);
 	struct usb_interface *intf = to_usb_interface(dev);
 	struct usb_device *udev;
-	int error;
+	int error, r;
 
 	intf->condition = USB_INTERFACE_UNBINDING;
 
@@ -290,11 +296,14 @@ static int usb_unbind_interface(struct device *dev)
 		 * Just re-enable it without affecting the endpoint toggles.
 		 */
 		usb_enable_interface(udev, intf, false);
-	} else if (!error && intf->dev.power.status == DPM_ON)
-		usb_set_interface(udev, intf->altsetting[0].
+	} else if (!error && intf->dev.power.status == DPM_ON) {
+		r = usb_set_interface(udev, intf->altsetting[0].
 				desc.bInterfaceNumber, 0);
-	else
+		if (r < 0)
+			intf->needs_altsetting0 = 1;
+	} else {
 		intf->needs_altsetting0 = 1;
+	}
 	usb_set_intfdata(intf, NULL);
 
 	intf->condition = USB_INTERFACE_UNBOUND;

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html