drivers/gpu/drm/i915/display/intel_display.c:3934 skl_plane_stride() error: testing array offset 'color_plane' after use.

[Dan Carpenter]

tree:   https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   a7f89616b7376495424f682b6086e0c391a89a1d
commit: df0566a641f959108c152be748a0a58794280e0e drm/i915: move modesetting core code under display/
date:   3 months ago

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

New smatch warnings:
drivers/gpu/drm/i915/display/intel_display.c:3934 skl_plane_stride() error: testing array offset 'color_plane' after use.
drivers/gpu/drm/i915/display/intel_display.c:16328 intel_sanitize_encoder() error: we previously assumed 'crtc' could be null (see line 16318)

git remote add linus https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux.git
git remote update linus
git checkout df0566a641f959108c152be748a0a58794280e0e
vim +/color_plane +3934 drivers/gpu/drm/i915/display/intel_display.c

b3cf5c06ca5001 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-25  3926  
df79cf44191029 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-11  3927  u32 skl_plane_stride(const struct intel_plane_state *plane_state,
5d2a19507cb665 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-07  3928  		     int color_plane)
d21967740f4b7d drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2016-01-28  3929  {
df79cf44191029 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-11  3930  	const struct drm_framebuffer *fb = plane_state->base.fb;
df79cf44191029 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-11  3931  	unsigned int rotation = plane_state->base.rotation;
5d2a19507cb665 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-07  3932  	u32 stride = plane_state->color_plane[color_plane].stride;
                                                                                                                              ^^^^^^^^^^^
Out of bounds read?

1b500535c513ac drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2017-03-07  3933  
5d2a19507cb665 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-07 @3934  	if (color_plane >= fb->format->num_planes)
                                                                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Tested too late.

1b500535c513ac drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2017-03-07  3935  		return 0;
1b500535c513ac drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2017-03-07  3936  
b3cf5c06ca5001 drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2018-09-25  3937  	return stride / skl_plane_stride_mult(fb, color_plane, rotation);
d21967740f4b7d drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2016-01-28  3938  }
d21967740f4b7d drivers/gpu/drm/i915/intel_display.c Ville Syrjälä 2016-01-28  3939  

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