Re: [PATCH] USB: gadget: udc: atmel: fix possible oops when unloading module

[Wu, Songjun]

å 12/24/2014 00:24, Felipe Balbi åé:
> On Mon, Dec 22, 2014 at 05:26:14PM +0800, Songjun Wu wrote:
> > When unloading the module, the urb request will be dequeued
> > and the completion routine will be excuted.
> > If no urb packet, the urb request will not be added to the endpoint queue
> > and the completion routine pointer in urb request is NULL.
> > Accessing to the NULL function pointer will cause the oops issue.
> > Add the code to check the urb request is in the endpoint queue or not.
> > If the urb request is not in the endpoint queue, a negative error code
> > will be returned.
>
> have you triggered the NULL pointer oops ? Care to add it to the commit
> log.

Executing the 'insmod g_hid.ko', then executing the 'rmmod g_hid.ko', 
the NULL pointer oops will be triggered.

> Also, which commit is this fixing ? Does this need to be backported ?
> When was the bug introduced ?
>
> > Signed-off-by: Songjun Wu <songjun.wu@xxxxxxxxx>
> > ---
> >   drivers/usb/gadget/udc/atmel_usba_udc.c |   12 +++++++++++-
> >   1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
> > index ce88237..48629cc 100644
> > --- a/drivers/usb/gadget/udc/atmel_usba_udc.c
> > +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
> > @@ -828,7 +828,7 @@ static int usba_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
> >   {
> >   	struct usba_ep *ep = to_usba_ep(_ep);
> >   	struct usba_udc *udc = ep->udc;
> > -	struct usba_request *req = to_usba_req(_req);
> > +	struct usba_request *req;
> >   	unsigned long flags;
> >   	u32 status;
> >
> > @@ -837,6 +837,16 @@ static int usba_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
> >
> >   	spin_lock_irqsave(&udc->lock, flags);
> >
> > +	list_for_each_entry(req, &ep->queue, queue) {
> > +		if (&req->req == _req)
> > +			break;
> > +	}
> > +
> > +	if (&req->req != _req) {
> > +		spin_unlock_irqrestore(&udc->lock, flags);
> > +		return -EINVAL;
> > +	}
> > +
> >   	if (req->using_dma) {
> >   		/*
> >   		 * If this request is currently being transferred,
> > --
> > 1.7.9.5
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