[PATCH] drm/i915: Handle null 'fb' in 'intel_plane_atomic_check_with_state'

[PATCH] drm/i915: Handle null 'fb' in 'intel_plane_atomic_check_with_state'

[Lu Yao]

Add null pointer check before use fb.
Reported by smatch.

Signed-off-by: Lu Yao <yaolu@kylinos.cn>
---
 drivers/gpu/drm/i915/display/intel_atomic_plane.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
index d89630b2d5c1..20bfa9589ee7 100644
--- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
@@ -640,18 +640,18 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
 	    intel_plane_is_scaled(new_plane_state))
 		new_crtc_state->scaled_planes |= BIT(plane->id);
 
-	if (new_plane_state->uapi.visible &&
+	if (fb && new_plane_state->uapi.visible &&
 	    intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier))
 		new_crtc_state->nv12_planes |= BIT(plane->id);
 
-	if (new_plane_state->uapi.visible &&
+	if (fb && new_plane_state->uapi.visible &&
 	    fb->format->format == DRM_FORMAT_C8)
 		new_crtc_state->c8_planes |= BIT(plane->id);
 
 	if (new_plane_state->uapi.visible || old_plane_state->uapi.visible)
 		new_crtc_state->update_planes |= BIT(plane->id);
 
-	if (new_plane_state->uapi.visible &&
+	if (fb && new_plane_state->uapi.visible &&
 	    intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier)) {
 		new_crtc_state->data_rate_y[plane->id] =
 			intel_plane_data_rate(new_crtc_state, new_plane_state, 0);
-- 
2.25.1

Re: [PATCH] drm/i915: Handle null 'fb' in 'intel_plane_atomic_check_with_state'

[Jani Nikula]

On Mon, 20 Jan 2025, Lu Yao <yaolu@kylinos.cn> wrote:
> Add null pointer check before use fb.
> Reported by smatch.

If new_plane_state->uapi.visible is true, fb will be non-NULL too, but
smatch is unable to see that.

Adding these checks makes one believe that this is not something you can
rely on.

BR,
Jani.

>
> Signed-off-by: Lu Yao <yaolu@kylinos.cn>
> ---
>  drivers/gpu/drm/i915/display/intel_atomic_plane.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> index d89630b2d5c1..20bfa9589ee7 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> @@ -640,18 +640,18 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
>  	    intel_plane_is_scaled(new_plane_state))
>  		new_crtc_state->scaled_planes |= BIT(plane->id);
>  
> -	if (new_plane_state->uapi.visible &&
> +	if (fb && new_plane_state->uapi.visible &&
>  	    intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier))
>  		new_crtc_state->nv12_planes |= BIT(plane->id);
>  
> -	if (new_plane_state->uapi.visible &&
> +	if (fb && new_plane_state->uapi.visible &&
>  	    fb->format->format == DRM_FORMAT_C8)
>  		new_crtc_state->c8_planes |= BIT(plane->id);
>  
>  	if (new_plane_state->uapi.visible || old_plane_state->uapi.visible)
>  		new_crtc_state->update_planes |= BIT(plane->id);
>  
> -	if (new_plane_state->uapi.visible &&
> +	if (fb && new_plane_state->uapi.visible &&
>  	    intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier)) {
>  		new_crtc_state->data_rate_y[plane->id] =
>  			intel_plane_data_rate(new_crtc_state, new_plane_state, 0);

-- 
Jani Nikula, Intel

✗ i915.CI.BAT: failure for drm/i915: Handle null 'fb' in 'intel_plane_atomic_check_with_state'

[Patchwork]

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== Series Details ==

Series: drm/i915: Handle null 'fb' in 'intel_plane_atomic_check_with_state'
URL   : https://patchwork.freedesktop.org/series/143795/
State : failure

== Summary ==

CI Bug Log - changes from CI_DRM_15992 -> Patchwork_143795v1
====================================================

Summary
-------

  **FAILURE**

  Serious unknown changes coming with Patchwork_143795v1 absolutely need to be
  verified manually.
  
  If you think the reported changes have nothing to do with the changes
  introduced in Patchwork_143795v1, please notify your bug team (I915-ci-infra@lists.freedesktop.org) to allow them
  to document this new failure mode, which will reduce false positives in CI.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/index.html

Participating hosts (39 -> 39)
------------------------------

  No changes in participating hosts

Possible new issues
-------------------

  Here are the unknown changes that may have been introduced in Patchwork_143795v1:

### IGT changes ###

#### Possible regressions ####

  * igt@kms_flip@basic-plain-flip:
    - fi-cfl-8109u:       [PASS][1] -> [DMESG-WARN][2] +3 other tests dmesg-warn
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_15992/fi-cfl-8109u/igt@kms_flip@basic-plain-flip.html
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/fi-cfl-8109u/igt@kms_flip@basic-plain-flip.html

  
Known issues
------------

  Here are the changes found in Patchwork_143795v1 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@i915_pm_rpm@module-reload:
    - bat-dg1-7:          [PASS][3] -> [FAIL][4] ([i915#13401])
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_15992/bat-dg1-7/igt@i915_pm_rpm@module-reload.html
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/bat-dg1-7/igt@i915_pm_rpm@module-reload.html

  * igt@kms_pipe_crc_basic@nonblocking-crc-frame-sequence:
    - bat-dg2-11:         [PASS][5] -> [SKIP][6] ([i915#9197]) +3 other tests skip
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_15992/bat-dg2-11/igt@kms_pipe_crc_basic@nonblocking-crc-frame-sequence.html
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/bat-dg2-11/igt@kms_pipe_crc_basic@nonblocking-crc-frame-sequence.html

  
#### Possible fixes ####

  * igt@i915_selftest@live:
    - bat-mtlp-8:         [DMESG-FAIL][7] ([i915#12061]) -> [PASS][8] +1 other test pass
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_15992/bat-mtlp-8/igt@i915_selftest@live.html
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/bat-mtlp-8/igt@i915_selftest@live.html
    - bat-adlp-11:        [ABORT][9] ([i915#13399]) -> [PASS][10]
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_15992/bat-adlp-11/igt@i915_selftest@live.html
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/bat-adlp-11/igt@i915_selftest@live.html

  * igt@i915_selftest@live@guc:
    - bat-adlp-11:        [ABORT][11] -> [PASS][12]
   [11]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_15992/bat-adlp-11/igt@i915_selftest@live@guc.html
   [12]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/bat-adlp-11/igt@i915_selftest@live@guc.html

  * igt@i915_selftest@live@workarounds:
    - {bat-arls-6}:       [DMESG-FAIL][13] ([i915#12061]) -> [PASS][14] +1 other test pass
   [13]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_15992/bat-arls-6/igt@i915_selftest@live@workarounds.html
   [14]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/bat-arls-6/igt@i915_selftest@live@workarounds.html

  
  {name}: This element is suppressed. This means it is ignored when computing
          the status of the difference (SUCCESS, WARNING, or FAILURE).

  [i915#12061]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12061
  [i915#13399]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13399
  [i915#13401]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13401
  [i915#9197]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/9197


Build changes
-------------

  * Linux: CI_DRM_15992 -> Patchwork_143795v1

  CI-20190529: 20190529
  CI_DRM_15992: d471f521da387883809f72b139a2013c0652bee1 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_8203: 3dce04be4ed4c0e729d80f70caff8ae8a869b5c0 @ https://gitlab.freedesktop.org/drm/igt-gpu-tools.git
  Patchwork_143795v1: d471f521da387883809f72b139a2013c0652bee1 @ git://anongit.freedesktop.org/gfx-ci/linux

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_143795v1/index.html

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