Messages in this thread | | | Subject | Re: [PATCH] USB testing driver: convert dev->sem to mutex | From | Daniel Walker <> | Date | Tue, 04 Dec 2007 11:09:02 -0800 |
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On Tue, 2007-12-04 at 17:55 +0100, Matthias Kaehlcke wrote: > @@ -1990,7 +1991,7 @@ static void usbtest_disconnect (struct > usb_interface *intf) > { > struct usbtest_dev *dev = usb_get_intfdata (intf); > > - down (&dev->sem); > + mutex_lock(&dev->lock); > > usb_set_intfdata (intf, NULL); > dev_dbg (&intf->dev, "disconnect\n");
This looks like a bit of an anomaly.. The code that isn't shown above is the "kfree(dev)" .. So this isn't legal since it's freeing a locked mutex. Here's a excerpt from the comment above mutex_lock(),
* The mutex must later on be released by the same task that * acquired it. Recursive locking is not allowed. The task * may not exit without first unlocking the mutex. Also, kernel * memory where the mutex resides mutex must not be freed with * the mutex still locked. The mutex must first be initialized * (or statically defined) before it can be locked. memset()-ing * the mutex to 0 is not allowed.
Daniel
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