USB: Phidget: fix race in device_create

There is a race from when a device is created with device_create() and
then the drvdata is set with a call to dev_set_drvdata() in which a
sysfs file could be open, yet the drvdata will be NULL, causing all
sorts of bad things to happen.

This patch fixes the problem by using the new function,
device_create_drvdata().  It fixes all 3 phidget drivers, which all have
the same problem.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Sean Young <sean@mess.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 9 insertions, 10 deletions

diff --git a/drivers/usb/misc/phidgetkit.c b/drivers/usb/misc/phidgetkit.c
index 24230c6..4cfa25b 100644
--- a/drivers/usb/misc/phidgetkit.c
+++ b/drivers/usb/misc/phidgetkit.c
@@ -595,14 +595,14 @@ static int interfacekit_probe(struct usb_interface *intf, const struct usb_devic
         } while(value);
         kit->dev_no = bit;
 
-        kit->dev = device_create(phidget_class, &kit->udev->dev, 0,
-               		"interfacekit%d", kit->dev_no);
+	kit->dev = device_create_drvdata(phidget_class, &kit->udev->dev,
+					MKDEV(0, 0), kit,
+					"interfacekit%d", kit->dev_no);
         if (IS_ERR(kit->dev)) {
                 rc = PTR_ERR(kit->dev);
                 kit->dev = NULL;
                 goto out;
         }
-	dev_set_drvdata(kit->dev, kit);
 
 	if (usb_submit_urb(kit->irq, GFP_KERNEL)) {
 		rc = -EIO;
diff --git a/drivers/usb/misc/phidgetmotorcontrol.c b/drivers/usb/misc/phidgetmotorcontrol.c
index f0113c1..9b4696f 100644
--- a/drivers/usb/misc/phidgetmotorcontrol.c
+++ b/drivers/usb/misc/phidgetmotorcontrol.c
@@ -365,16 +365,15 @@ static int motorcontrol_probe(struct usb_interface *intf, const struct usb_devic
 	} while(value);
 	mc->dev_no = bit;
 
-	mc->dev = device_create(phidget_class, &mc->udev->dev, 0,
-				"motorcontrol%d", mc->dev_no);
+	mc->dev = device_create_drvdata(phidget_class, &mc->udev->dev,
+					MKDEV(0, 0), mc,
+					"motorcontrol%d", mc->dev_no);
 	if (IS_ERR(mc->dev)) {
 		rc = PTR_ERR(mc->dev);
 		mc->dev = NULL;
 		goto out;
 	}
 
-	dev_set_drvdata(mc->dev, mc);
-
 	if (usb_submit_urb(mc->irq, GFP_KERNEL)) {
 		rc = -EIO;
 		goto out;
diff --git a/drivers/usb/misc/phidgetservo.c b/drivers/usb/misc/phidgetservo.c
index 7d590c0..1ca7ddb 100644
--- a/drivers/usb/misc/phidgetservo.c
+++ b/drivers/usb/misc/phidgetservo.c
@@ -275,14 +275,14 @@ servo_probe(struct usb_interface *interface, const struct usb_device_id *id)
         } while (value);
 	dev->dev_no = bit;
 
-	dev->dev = device_create(phidget_class, &dev->udev->dev, 0,
-				 "servo%d", dev->dev_no);
+	dev->dev = device_create_drvdata(phidget_class, &dev->udev->dev,
+					 MKDEV(0, 0), dev,
+					 "servo%d", dev->dev_no);
 	if (IS_ERR(dev->dev)) {
 		rc = PTR_ERR(dev->dev);
 		dev->dev = NULL;
 		goto out;
 	}
-	dev_set_drvdata(dev->dev, dev);
 
 	servo_count = dev->type & SERVO_COUNT_QUAD ? 4 : 1;