[Intel-gfx] [PATCH] drm/i915: Prevent dereference of engine before NULL check in error capture

[Tvrtko Ursulin]

On 21/06/2019 14:52, Chris Wilson wrote:
> drivers/gpu/drm/i915//i915_gpu_error.c:1418 gem_record_rings() warn: variable dereferenced before check 'engine' (see line 1413)
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_gpu_error.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
> index 59f5b0265ee3..5489cd879315 100644
> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
> @@ -1410,7 +1410,6 @@ static void gem_record_rings(struct i915_gpu_state *error)
>   	for (i = 0; i < I915_NUM_ENGINES; i++) {
>   		struct intel_engine_cs *engine = i915->engine[i];
>   		struct drm_i915_error_engine *ee = &error->engine[i];
> -		struct i915_ggtt *ggtt = engine->gt->ggtt;
>   		struct i915_request *request;
>   
>   		ee->engine_id = -1;
> @@ -1428,7 +1427,7 @@ static void gem_record_rings(struct i915_gpu_state *error)
>   			struct i915_gem_context *ctx = request->gem_context;
>   			struct intel_ring *ring;
>   
> -			ee->vm = ctx->vm ?: &ggtt->vm;
> +			ee->vm = ctx->vm ?: &engine->gt->ggtt->vm;
>   
>   			record_context(&ee->context, ctx);
>   
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko