[PATCH] USB: handle usb host allocation failures gracefully

It looks like a host (like ohci or whatever) could try to allocate a new
usb_device structure with usb_alloc_dev and get back a valid pointer even if
the allocation of its private data failed.  I first saw this in the 2.4
sources, but it looks like 2.6 has the same problem.  This patch attempts to
fix it by freeing dev if the ->allocate() routine fails, and then returns
NULL instead of a potentially dangerous dev pointer.
Signed-off-by: Jesse Barnes <jbarnes@sgi.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/usb/core/usb.c

@@ -775,7 +775,10 @@ usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port)
 	init_MUTEX(&dev->serialize);
 
 	if (dev->bus->op->allocate)
-		dev->bus->op->allocate(dev);
+		if (dev->bus->op->allocate(dev)) {
+			kfree(dev);
+			return NULL;
+		}
 
 	return dev;
 }