Hi, On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > Some gadget drivers may attempt to dequeue requests for an endpoint that has > already been disabled. For example, in the UVC gadget driver, > uvc_function_set_alt() > will call usb_ep_disable() when alt setting 0 is selected. When the userspace > application subsequently issues the VIDIOC_STREAMOFF ioctl, uvc_video_enable() > invokes usb_ep_dequeue() to ensure that all requests have been cancelled.
bug is on uvc gadget, then. Laurent ? Also, fsl should be removed from the tree, I'm trying to persuade iMX folks to use drivers/usb/chipidea instead. > For the Freescale High Speed Dual-Role USB controller, fsl_ep_dequeue() > provides > the implementation of usb_ep_dequeue(). If this is called for a disabled > endpoint, > a kernel oops will occur when the ep->ep.desc field is dereferenced (by > ep_index()). > fsl_ep_disable() sets this field to NULL, as well as deleting all pending > requests > for the endpoint. > > This patch adds an additional check to fsl_ep_dequeue() to ensure that the > endpoint has not already been disabled before attempting to dequeue requests. > > Signed-off-by: Simon Haggett <simon.hagg...@realvnc.com> > --- > drivers/usb/gadget/fsl_udc_core.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/drivers/usb/gadget/fsl_udc_core.c > b/drivers/usb/gadget/fsl_udc_core.c > index 6ae70cb..acd513b 100644 > --- a/drivers/usb/gadget/fsl_udc_core.c > +++ b/drivers/usb/gadget/fsl_udc_core.c > @@ -955,7 +955,10 @@ static int fsl_ep_dequeue(struct usb_ep *_ep, struct > usb_request *_req) > int ep_num, stopped, ret = 0; > u32 epctrl; > > - if (!_ep || !_req) > + /* Ensure that the ep and request are valid, and the ep is not > + * disabled > + */ > + if (!_ep || !_req || !ep->ep.desc) > return -EINVAL; > > spin_lock_irqsave(&ep->udc->lock, flags); > -- > 1.7.4.1 > -- balbi
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