diff options
| author | Kevin Cernekee <cernekee@gmail.com> | 2012-08-09 12:23:52 +0400 |
|---|---|---|
| committer | Felipe Balbi <balbi@ti.com> | 2012-08-23 12:04:19 +0400 |
| commit | 974e9323deefbab923d7aa8f0e4bcf9066c2ec97 (patch) | |
| tree | 8498d854cb728eddb03b1cf71611e2da6e2c70dc /drivers/usb/gadget/udc-core.c | |
| parent | d3091cfff73ce44c6b0cb61b25074f0ac648604f (diff) | |
| download | linux-974e9323deefbab923d7aa8f0e4bcf9066c2ec97.tar.xz | |
usb: gadget: udc-core: Race between disconnect/unbind and setup
usb_gadget_remove_driver() runs through a four-step sequence to shut down
the gadget driver. For the case of a composite gadget + at91 UDC, this
would look like:
udc->driver->disconnect(udc->gadget); // composite_disconnect()
usb_gadget_disconnect(udc->gadget); // at91_pullup(gadget, 0)
udc->driver->unbind(udc->gadget); // composite_unbind()
usb_gadget_udc_stop(udc->gadget, udc->driver); // at91_stop()
The UDC driver can receive SETUP packets from the host up until the
point when usb_gadget_disconnect() returns. On rare occasions, the
gadget driver may see this sequence:
udc->driver->disconnect(udc->gadget); // composite_disconnect()
udc->driver->setup(udc->gadget, &ctrl); // composite_setup()
udc->driver->unbind(udc->gadget); // composite_unbind()
Some gadget drivers, such as composite, assume this will never happen
and crash as a result.
The fix is to quiesce the UDC hardware (via usb_gadget_disconnect)
before running the gadget driver through the disconnect/unbind sequence.
Reviewed-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Diffstat (limited to 'drivers/usb/gadget/udc-core.c')
| -rw-r--r-- | drivers/usb/gadget/udc-core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/gadget/udc-core.c b/drivers/usb/gadget/udc-core.c index e5e44f8cde9a..bae243c23141 100644 --- a/drivers/usb/gadget/udc-core.c +++ b/drivers/usb/gadget/udc-core.c @@ -262,8 +262,8 @@ static void usb_gadget_remove_driver(struct usb_udc *udc) kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE); if (udc_is_newstyle(udc)) { - udc->driver->disconnect(udc->gadget); usb_gadget_disconnect(udc->gadget); + udc->driver->disconnect(udc->gadget); udc->driver->unbind(udc->gadget); usb_gadget_udc_stop(udc->gadget, udc->driver); } else { |