On Fri, Aug 26, 2022 at 11:38:14AM +0300, Jani Nikula wrote:
> Avoid BUG_ON(). Actually check the dpll count and bail out loudly with
> drm_WARN_ON() from the loop before overflowing
> i915->dpll.shared_dplls[].
> 
> Signed-off-by: Jani Nikula <jani.nik...@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dpll_mgr.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c 
> b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> index 118598c9a809..8dd405553cfa 100644
> --- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> +++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
> @@ -4199,6 +4199,10 @@ void intel_shared_dpll_init(struct drm_i915_private 
> *dev_priv)
>       dpll_info = dpll_mgr->dpll_info;
>  
>       for (i = 0; dpll_info[i].name; i++) {
> +             if (drm_WARN_ON(&dev_priv->drm,
> +                             i >= ARRAY_SIZE(dev_priv->dpll.shared_dplls)))
> +                     break;

Shame we can't neatly use a BUILD_BUG_ON() when assigning .dpll_info.

For patches 2-5
Reviewed-by: Ville Syrjälä <ville.syrj...@linux.intel.com>

> +
>               drm_WARN_ON(&dev_priv->drm, i != dpll_info[i].id);
>               dev_priv->dpll.shared_dplls[i].info = &dpll_info[i];
>       }
> @@ -4206,8 +4210,6 @@ void intel_shared_dpll_init(struct drm_i915_private 
> *dev_priv)
>       dev_priv->dpll.mgr = dpll_mgr;
>       dev_priv->dpll.num_shared_dpll = i;
>       mutex_init(&dev_priv->dpll.lock);
> -
> -     BUG_ON(dev_priv->dpll.num_shared_dpll > I915_NUM_PLLS);
>  }
>  
>  /**
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel

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