[PATCH 1/3] drm/tegra: Fix lockup on a use of staging API

[Mikko Perttunen]

Reviewed-by: Mikko Perttunen <mperttunen at nvidia.com>

On 05/12/2017 10:00 PM, Dmitry Osipenko wrote:
> Commit bdd2f9cd ("Don't leak kernel pointer to userspace") added a mutex
> around staging IOCTL's, some of those mutexes are taken twice.
>
> 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 | 20 ++++----------------
>  1 file changed, 4 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> index ab2dfd4e4bd9..768750226452 100644
> --- a/drivers/gpu/drm/tegra/drm.c
> +++ b/drivers/gpu/drm/tegra/drm.c
> @@ -430,18 +430,6 @@ int tegra_drm_submit(struct tegra_drm_context *context,
>
>
>  #ifdef CONFIG_DRM_TEGRA_STAGING
> -static struct tegra_drm_context *
> -tegra_drm_file_get_context(struct tegra_drm_file *file, u32 id)
> -{
> -	struct tegra_drm_context *context;
> -
> -	mutex_lock(&file->lock);
> -	context = idr_find(&file->contexts, id);
> -	mutex_unlock(&file->lock);
> -
> -	return context;
> -}
> -
>  static int tegra_gem_create(struct drm_device *drm, void *data,
>  			    struct drm_file *file)
>  {
> @@ -585,7 +573,7 @@ static int tegra_close_channel(struct drm_device *drm, void *data,
>
>  	mutex_lock(&fpriv->lock);
>
> -	context = tegra_drm_file_get_context(fpriv, args->context);
> +	context = idr_find(&fpriv->contexts, args->context);
>  	if (!context) {
>  		err = -EINVAL;
>  		goto unlock;
> @@ -610,7 +598,7 @@ static int tegra_get_syncpt(struct drm_device *drm, void *data,
>
>  	mutex_lock(&fpriv->lock);
>
> -	context = tegra_drm_file_get_context(fpriv, args->context);
> +	context = idr_find(&fpriv->contexts, args->context);
>  	if (!context) {
>  		err = -ENODEV;
>  		goto unlock;
> @@ -639,7 +627,7 @@ static int tegra_submit(struct drm_device *drm, void *data,
>
>  	mutex_lock(&fpriv->lock);
>
> -	context = tegra_drm_file_get_context(fpriv, args->context);
> +	context = idr_find(&fpriv->contexts, args->context);
>  	if (!context) {
>  		err = -ENODEV;
>  		goto unlock;
> @@ -664,7 +652,7 @@ static int tegra_get_syncpt_base(struct drm_device *drm, void *data,
>
>  	mutex_lock(&fpriv->lock);
>
> -	context = tegra_drm_file_get_context(fpriv, args->context);
> +	context = idr_find(&fpriv->contexts, args->context);
>  	if (!context) {
>  		err = -ENODEV;
>  		goto unlock;
>