On 2018-12-21 4:10 a.m., Yu Zhao wrote:
> Userspace may request pitch alignment that is not supported by GPU.
> Some requests 32, but GPU ignores it and uses default 64 when cpp is
> 4. If GEM object is allocated based on the smaller alignment, GPU
> DMA will go out of bound.
>
> For GPU that does frame buffer compression, DMA writing out of bound
> memory will cause memory corruption.
>
> Signed-off-by: Yu Zhao <yuz...@google.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> index e309d26170db..755daa332f8a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> @@ -527,6 +527,15 @@ amdgpu_display_user_framebuffer_create(struct drm_device
> *dev,
> struct drm_gem_object *obj;
> struct amdgpu_framebuffer *amdgpu_fb;
> int ret;
> + struct amdgpu_device *adev = dev->dev_private;
> + int cpp = drm_format_plane_cpp(mode_cmd->pixel_format, 0);
> + int pitch = amdgpu_align_pitch(adev, mode_cmd->width, cpp, false);
> +
> + if (mode_cmd->pitches[0] != pitch) {
> + dev_err(&dev->pdev->dev, "Invalid pitch: expecting %d but got
> %d\n",
> + pitch, mode_cmd->pitches[0]);
This message shouldn't be printed by default, or buggy / malicious
userspace can spam dmesg. I suggest using DRM_DEBUG_KMS or DRM_DEBUG_DRIVER.
> + return ERR_PTR(-EINVAL);
> + }
>
> obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[0]);
> if (obj == NULL) {
>
Other than that, looks good to me.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
