On Wed, 2016-11-16 at 13:15 -0200, Mauro Carvalho Chehab wrote:
> As reported by smatch:
> drivers/media/usb/usbtv/usbtv-video.c:716 usbtv_s_ctrl() error:
> doing dma on the stack (data)
> drivers/media/usb/usbtv/usbtv-video.c:758 usbtv_s_ctrl() error:
> doing dma on the stack (data)
>
> We should not do it, as it won't work on Kernels 4.9 and upper.
> So, alloc a buffer for it.
>
> Fixes: c53a846c48f2 ("[media] usbtv: add video controls")
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/usb/usbtv/usbtv-video.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/usb/usbtv/usbtv-video.c
> b/drivers/media/usb/usbtv/usbtv-video.c
> index 86ffbf8780f2..d3b6d3dfaa09 100644
> --- a/drivers/media/usb/usbtv/usbtv-video.c
> +++ b/drivers/media/usb/usbtv/usbtv-video.c
> @@ -704,10 +704,14 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
> {
> struct usbtv *usbtv = container_of(ctrl->handler, struct
> usbtv,
> ctrl
> );
> - u8 data[3];
> + u8 *data;
> u16 index, size;
> int ret;
>
> + data = kmalloc(3, GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> /*
> * Read in the current brightness/contrast registers. We
> need them
> * both, because the values are for some reason interleaved.
> @@ -717,6 +721,8 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
> usb_sndctrlpipe(usbtv->udev, 0),
> USBTV_CONTROL_REG,
> USB_DIR_OUT | USB_TYPE_VENDOR |
> USB_RECIP_DEVICE,
> 0, USBTV_BASE + 0x0244, (void *)data, 3, 0);
> + if (ret < 0)
> + goto error;
> }
>
> switch (ctrl->id) {
> @@ -752,6 +758,7 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
> }
> break;
> default:
> + kfree(data);
> return -EINVAL;
> }
>
> @@ -759,12 +766,13 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
> USBTV_CONTROL_REG,
> USB_DIR_OUT | USB_TYPE_VENDOR |
> USB_RECIP_DEVICE,
> 0, index, (void *)data, size, 0);
> - if (ret < 0) {
> +
> +error:
> + if (ret < 0)
> dev_warn(usbtv->dev, "Failed to submit a control
> request.\n");
> - return ret;
> - }
>
> - return 0;
> + kfree(data);
> + return ret;
> }
>
> static const struct v4l2_ctrl_ops usbtv_ctrl_ops = {
Reviewed-by: Lubomir Rintel <lkundrak@xxxxx>
Thank you,
Lubo
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