Re: [PATCH 1/4] drm/msm: fix memleak on release

[Johan Hovold]

On Thu, Oct 10, 2019 at 03:13:30PM +0200, Johan Hovold wrote:
> If a process is interrupted while accessing the "gpu" debugfs file and
> the drm device struct_mutex is contended, release() could return early
> and fail to free related resources.
> 
> Note that the return value from release() is ignored.
> 
> Fixes: 4f776f4511c7 ("drm/msm/gpu: Convert the GPU show function to use the GPU state")
> Cc: stable <stable@xxxxxxxxxxxxxxx>     # 4.18
> Cc: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
> Cc: Rob Clark <robdclark@xxxxxxxxx>
> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
> ---

Rob, Sean,

Sending a reminder about this one, which is not yet in linux-next.

Perhaps Daniel can pick it up otherwise?

Thanks,
Johan

>  drivers/gpu/drm/msm/msm_debugfs.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c
> index 6be879578140..1c74381a4fc9 100644
> --- a/drivers/gpu/drm/msm/msm_debugfs.c
> +++ b/drivers/gpu/drm/msm/msm_debugfs.c
> @@ -47,12 +47,8 @@ static int msm_gpu_release(struct inode *inode, struct file *file)
>  	struct msm_gpu_show_priv *show_priv = m->private;
>  	struct msm_drm_private *priv = show_priv->dev->dev_private;
>  	struct msm_gpu *gpu = priv->gpu;
> -	int ret;
> -
> -	ret = mutex_lock_interruptible(&show_priv->dev->struct_mutex);
> -	if (ret)
> -		return ret;
>  
> +	mutex_lock(&show_priv->dev->struct_mutex);
>  	gpu->funcs->gpu_state_put(show_priv->state);
>  	mutex_unlock(&show_priv->dev->struct_mutex);