Re: [PATCH] drivers/video: Bad error test before a dereference

[Nicolas Ferre]

Julien Brunel :
> The error test that follows the call to backlight_device_register
> semms not to concern the right variable.
>
> A simplified version of the semantic match that finds this problem is
> as follows: 
> (http://www.emn.fr/x-info/coccinelle/)
> // <smpl>
> @def0@
> expression x;
> position p0;
> @@
> x@p0 = backlight_device_register(...)
>
> @protected@
> expression def0.x,E;
> position def0.p0;
> position p;
> statement S;
> @@
> x@p0
> ... when != x = E
> if (!IS_ERR(x) && ...) {<... x@p ...>} else S
>
> @unprotected@
> expression def0.x;
> identifier fld;
> position def0.p0;
> position p != protected.p;
> @@
> x@p0
> ... when != x = E
> * x@p->fld
> // </smpl>
>
> Signed-off-by: Julien Brunel <brunel@xxxxxxx>
> Signed-off-by: Julia Lawall <julia@xxxxxxx>

Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>

> ---
>  drivers/video/atmel_lcdfb.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff -u -p a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
> --- a/drivers/video/atmel_lcdfb.c
> +++ b/drivers/video/atmel_lcdfb.c
> @@ -132,7 +132,7 @@ static void init_backlight(struct atmel_
>  
>  	bl = backlight_device_register("backlight", &sinfo->pdev->dev,
>  			sinfo, &atmel_lcdc_bl_ops);
> -	if (IS_ERR(sinfo->backlight)) {
> +	if (IS_ERR(bl)) {
>  		dev_err(&sinfo->pdev->dev, "error %ld on backlight register\n",
>  				PTR_ERR(bl));
>  		return;

Thanks, regards,
--
Nicolas Ferre

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/