[ 18/49] usb: gadget: fix a bug and a WARN_ON in dummy-hcd

Greg Kroah-Hartman
2013-09-29T19:57:21Z

From: Alan Stern <stern@rowland.harvard.edu>

commit 5f5610f69be3a925b1f79af27150bb7377bc9ad6 upstream.

This patch fixes a NULL pointer dereference and a WARN_ON in
dummy-hcd. These things were the result of moving to the UDC core
framework, and possibly of changes to that framework.

Now unloading a gadget driver causes the UDC to be stopped after the
gadget driver is unbound, not before. Therefore the "driver" argument
to dummy_udc_stop() can be NULL, so we must not try to print the
driver's name without checking first.

Also, the UDC framework automatically unregisters the gadget when the
UDC is deleted. Therefore a sysfs attribute file attached to the
gadget must be removed before the UDC is deleted, not after.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/gadget/dummy_hcd.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/usb/gadget/dummy_hcd.c
+++ b/drivers/usb/gadget/dummy_hcd.c
@@ -923,8 +923,9 @@ static int dummy_udc_stop(struct usb_gad
struct dummy_hcd *dum_hcd = gadget_to_dummy_hcd(g);
struct dummy *dum = dum_hcd->dum;

- dev_dbg(udc_dev(dum), "unregister gadget driver '%s'\n",
- driver->driver.name);
+ if (driver)
+ dev_dbg(udc_dev(dum), "unregister gadget driver '%s'\n",
+ driver->driver.name);

dum->driver = NULL;

@@ -1000,8 +1001,8 @@ static int dummy_udc_remove(struct platf
{
struct dummy *dum = platform_get_drvdata(pdev);

- usb_del_gadget_udc(&dum->gadget);
device_remove_file(&dum->gadget.dev, &dev_attr_function);
+ usb_del_gadget_udc(&dum->gadget);
return 0;
}