[Intel-gfx] [PATCH] drm/i915: Do not dereference NULL bo->resource

[Gupta, Anshuman]

> -----Original Message-----
> From: Das, Nirmoy <nirmoy.das at intel.com>
> Sent: Monday, September 19, 2022 8:33 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Auld, Matthew
> <matthew.auld at intel.com>; Gupta, Anshuman <anshuman.gupta at intel.com>
> Subject: [PATCH] drm/i915: Do not dereference NULL bo->resource
> 
> bo->resource could be NULL hence add a NULL check for resource before
> bo->dereferencing it.
Will bo->resource will be NULL only in case of object is smem or it can be NULL even in lmem case as well ?
Thanks,
Anshuman Gupta. 
> 
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/6850
> Fixes: ad74457a6b5a96 ("drm/i915/dgfx: Release mmap on rpm suspend")
> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 0544b0a4a43a..8608801cd9ab 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -513,7 +513,7 @@ static void i915_ttm_delete_mem_notify(struct
> ttm_buffer_object *bo)
> 
>  	if (likely(obj)) {
>  		/* ttm_bo_release() already has dma_resv_lock */
> -		if (i915_ttm_cpu_maps_iomem(bo->resource))
> +		if (bo->resource && i915_ttm_cpu_maps_iomem(bo-
> >resource))
>  			wakeref = intel_runtime_pm_get(&to_i915(obj-
> >base.dev)->runtime_pm);
> 
>  		__i915_gem_object_pages_fini(obj);
> --
> 2.37.3