[PATCH] drm/amd/amdgpu: Fix up locking etc in amdgpu_debugfs_gprwave_ioctl()

[Alex Deucher]

Applied.  Thanks!

Alex

On Thu, May 25, 2023 at 4:05 AM Dan Carpenter <dan.carpenter at linaro.org> wrote:
>
> There are two bugs here.
> 1) Drop the lock if copy_from_user() fails.
> 2) If the copy fails then the correct error code is -EFAULT instead of
>    -EINVAL.
>
> I also broke up the long line and changed "sizeof rd->id" to
> "sizeof(rd->id)".
>
> Fixes: 164fb2940933 ("drm/amd/amdgpu: Update debugfs for XCC support (v3)")
> Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> index c657bed350ac..56e89e76ff17 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> @@ -478,15 +478,16 @@ static ssize_t amdgpu_debugfs_gprwave_read(struct file *f, char __user *buf, siz
>  static long amdgpu_debugfs_gprwave_ioctl(struct file *f, unsigned int cmd, unsigned long data)
>  {
>         struct amdgpu_debugfs_gprwave_data *rd = f->private_data;
> -       int r;
> +       int r = 0;
>
>         mutex_lock(&rd->lock);
>
>         switch (cmd) {
>         case AMDGPU_DEBUGFS_GPRWAVE_IOC_SET_STATE:
> -               r = copy_from_user(&rd->id, (struct amdgpu_debugfs_gprwave_iocdata *)data, sizeof rd->id);
> -               if (r)
> -                       return r ? -EINVAL : 0;
> +               if (copy_from_user(&rd->id,
> +                                  (struct amdgpu_debugfs_gprwave_iocdata *)data,
> +                                  sizeof(rd->id)))
> +                       r = -EFAULT;
>                 goto done;
>         default:
>                 r = -EINVAL;
> --
> 2.39.2
>