[PATCH 2/3] drm/tegra: Correct idr_alloc() minimum id

[Mikko Perttunen]

On 05/12/2017 10:00 PM, Dmitry Osipenko wrote:
> The start = 0 is invalid and causes weird CDMA channel timeouts, presumably
> some memory misuse/corruption is going on.

What makes you think start = 0 is invalid? I can't see anything pointing 
to that in the idr code and there are many users in the kernel passing 0 
as start.

>
> Fixes: bdd2f9cd10eb ("drm/tegra: Don't leak kernel pointer to userspace")
> Signed-off-by: Dmitry Osipenko <digetx at gmail.com>
> ---
>  drivers/gpu/drm/tegra/drm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> index 768750226452..732c8d98044f 100644
> --- a/drivers/gpu/drm/tegra/drm.c
> +++ b/drivers/gpu/drm/tegra/drm.c
> @@ -518,7 +518,7 @@ static int tegra_client_open(struct tegra_drm_file *fpriv,
>  	if (err < 0)
>  		return err;
>
> -	err = idr_alloc(&fpriv->contexts, context, 0, 0, GFP_KERNEL);
> +	err = idr_alloc(&fpriv->contexts, context, 1, 0, GFP_KERNEL);
>  	if (err < 0) {
>  		client->ops->close_channel(context);
>  		return err;
>