PERFORCE change 167286 for review

[Hans Petter Selasky]

http://perforce.freebsd.org/chv.cgi?CH=167286

Change 167286 by hselasky at hselasky_laptop001 on 2009/08/13 12:44:04

	
	USB CORE:
	 - fix memory use after free race for USB character devices.
	 - reported by Lucius Windschuh

Affected files ...

.. //depot/projects/usb/src/sys/dev/usb/usb_device.c#49 edit

Differences ...

==== //depot/projects/usb/src/sys/dev/usb/usb_device.c#49 (text+ko) ====

@@ -1901,15 +1901,18 @@
 usb_cdev_free(struct usb_device *udev)
 {
 	struct usb_fs_privdata* pd;
+	struct cdev* pcdev;
 
 	DPRINTFN(2, "Freeing device nodes\n");
 
 	while ((pd = LIST_FIRST(&udev->pd_list)) != NULL) {
 		KASSERT(pd->cdev->si_drv1 == pd, ("privdata corrupt"));
 
-		destroy_dev_sched_cb(pd->cdev, usb_cdev_cleanup, pd);
+		pcdev = pd->cdev;
 		pd->cdev = NULL;
 		LIST_REMOVE(pd, pd_next);
+		if (pcdev != NULL)
+			destroy_dev_sched_cb(pcdev, usb_cdev_cleanup, pd);
 	}
 }