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Subject[PATCH 048/104] usb: gadget: fix a bug and a WARN_ON in dummy-hcd
Date
3.8.13.11 -stable review patch.  If anyone has any objections, please let me know.

------------------

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>
[ kamal: backport to 3.8 (context) ]
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/usb/gadget/dummy_hcd.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/dummy_hcd.c b/drivers/usb/gadget/dummy_hcd.c
index 8cf0c0f..b693889 100644
--- a/drivers/usb/gadget/dummy_hcd.c
+++ b/drivers/usb/gadget/dummy_hcd.c
@@ -924,8 +924,9 @@ static int dummy_udc_stop(struct usb_gadget *g,
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->gadget.dev.driver = NULL;
dum->driver = NULL;
@@ -1016,10 +1017,10 @@ static int dummy_udc_remove(struct platform_device *pdev)
{
struct dummy *dum = platform_get_drvdata(pdev);

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

--
1.8.1.2


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