Re: drivers/gpu/drm/i915/display/intel_display.c:3934 skl_plane_stride() error: testing array offset 'color_plane' after use.
From: Jani Nikula
Date: Mon Sep 16 2019 - 03:30:46 EST
On Sat, 14 Sep 2019, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> 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)
Odd, what changed to provoke the warnings now? Or is the smatch test
new?
Anyway, Cc: Ville & intel-gfx.
BR,
Jani.
>
> 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 SyrjÃlà 2018-09-25 3926
> df79cf44191029 drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2018-09-11 3927 u32 skl_plane_stride(const struct intel_plane_state *plane_state,
> 5d2a19507cb665 drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2018-09-07 3928 int color_plane)
> d21967740f4b7d drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2016-01-28 3929 {
> df79cf44191029 drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2018-09-11 3930 const struct drm_framebuffer *fb = plane_state->base.fb;
> df79cf44191029 drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2018-09-11 3931 unsigned int rotation = plane_state->base.rotation;
> 5d2a19507cb665 drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 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 SyrjÃlà 2017-03-07 3933
> 5d2a19507cb665 drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2018-09-07 @3934 if (color_plane >= fb->format->num_planes)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Tested too late.
>
> 1b500535c513ac drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2017-03-07 3935 return 0;
> 1b500535c513ac drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2017-03-07 3936
> b3cf5c06ca5001 drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2018-09-25 3937 return stride / skl_plane_stride_mult(fb, color_plane, rotation);
> d21967740f4b7d drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2016-01-28 3938 }
> d21967740f4b7d drivers/gpu/drm/i915/intel_display.c Ville SyrjÃlà 2016-01-28 3939
>
> ---
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--
Jani Nikula, Intel Open Source Graphics Center