Am Dienstag, 24. April 2012, 17:46:41 schrieb Ming Lei:
> On Tue, Apr 24, 2012 at 10:22 PM, Oliver Neukum <oneukum@xxxxxxx> wrote:
> > Am Dienstag, 24. April 2012, 06:19:00 schrieb Ming Lei:
> >
> >> @@ -486,11 +494,15 @@ static void hid_ctrl(struct urb *urb)
> >>
> >> if (usbhid->ctrlhead != usbhid->ctrltail && !hid_submit_ctrl(hid)) {
> >> /* Successfully submitted next urb in queue */
> >> + if (status != -ECONNRESET)
> >> + spin_unlock(&usbhid->unlink_lock);
> >> spin_unlock(&usbhid->lock);
> >> return;
> >> }
> >>
> >> clear_bit(HID_CTRL_RUNNING, &usbhid->iofl);
> >> + if (status != -ECONNRESET)
> >> + spin_unlock(&usbhid->unlink_lock);
> >> spin_unlock(&usbhid->lock);
> >> usb_autopm_put_interface_async(usbhid->intf);
> >> wake_up(&usbhid->wait);
> >
> > Now you race against a double time out
> >
> > CPU A CPU B
> >
> > __usbhid_submit_report()
> > time_after()
> > usb_unlink_urb()
> > -- this has to go to the hardware -->
> > hid_irq_out()
> > if (status != -ECONNRESET)
> > --> no lock
> > hid_submit_out()
> > __usbhid_submit_report()
> > time_after()
> > usb_submit_urb()
>
> This submit won't happen because HID_OUT_RUNNING is not cleared.
I may be dense, but as far as I can tell a resubmit will happen, exactly if
HID_OUT_RUNNING is _not_ cleared.
Regards
Oliver
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