Re: [PATCH] staging: line6: toneport.c: Fix for possible null pointer dereference

[Stefan Hajnoczi]

On Mon, May 19, 2014 at 11:39 PM, Rickard Strandqvist
<rickard_strandqvist@xxxxxxxxxxxxxxxxxx> wrote:
> There is otherwise a risk of a possible null pointer dereference.
>
> Was largely found by using a static code analysis program called cppcheck.
>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@xxxxxxxxxxxxxxxxxx>
> ---
>  drivers/staging/line6/toneport.c |   14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/line6/toneport.c b/drivers/staging/line6/toneport.c
> index af2e7e5..36fe76d 100644
> --- a/drivers/staging/line6/toneport.c
> +++ b/drivers/staging/line6/toneport.c
> @@ -431,11 +431,15 @@ void line6_toneport_disconnect(struct usb_interface *interface)
>  {
>         struct usb_line6_toneport *toneport;
>         u16 idProduct;
> +       struct snd_line6_pcm *line6pcm;
>
>         if (interface == NULL)
>                 return;
>
>         toneport = usb_get_intfdata(interface);
> +       if (toneport == NULL)
> +               return;
> +
>         del_timer_sync(&toneport->timer);
>         idProduct = le16_to_cpu(toneport->line6.usbdev->descriptor.idProduct);
>
> @@ -444,13 +448,11 @@ void line6_toneport_disconnect(struct usb_interface *interface)
>                 device_remove_file(&interface->dev, &dev_attr_led_green);
>         }
>
> -       if (toneport != NULL) {
> -               struct snd_line6_pcm *line6pcm = toneport->line6.line6pcm;

Didn't look into this but it's the traditional "use before NULL
check".  Can't hurt to fix it.

Reviewed-by: Stefan Hajnoczi <stefanha@xxxxxxxxx>
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