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 yuzhao@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.