-----Original Message-----
From: Felipe Balbi [mailto:<redacted>]
Sent: Saturday, October 20, 2012 1:37 AM
To: Simon Haggett
Cc: Li Yang-R58472; Felipe Balbi; Greg Kroah-Hartman; linux-
usb@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; linux-
kernel@vger.kernel.org; Laurent Pinchart
Subject: Re: [PATCH 1/1] usb: gadget: Don't attempt to dequeue requests
for a disabled USB endpoint on Freescale hardware
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Hi,
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On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote:
quoted
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.
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bug is on uvc gadget, then. Laurent ?
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Also, fsl should be removed from the tree, I'm trying to persuade iMX
folks to use drivers/usb/chipidea instead.
Besides the iMX usage, the driver is also being used by many Freescale Powe=
rPC/Coldfire SoCs. I agree that it's ideal to move to a common driver. Bu=
t it is a large task to make the chipidea driver works for all the hardware=
that fsl_udc had supported and been tested on.
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quoted
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()).
quoted
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.
quoted
Signed-off-by: Simon Haggett <redacted>
---
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)
quoted
int ep_num, stopped, ret =3D 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
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--
balbi