Re: [PATCH] drm/i915/gem: Do not leak siblings[] on proto context error

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

On 7/1/26 09:30, Joonas Lahtinen wrote:
> After a successful BALANCE/PARALLEL_SUBMIT extension on context
> creation, error during processing of next user extension leaks
> the siblings[] array. Fix that.
> 
> Discovered using AI-assisted static analysis confirmed by
> Intel Product Security.
> 
> Reported-by: Martin Hodo <martin.hodo@intel.com>
> Fixes: d4433c7600f7 ("drm/i915/gem: Use the proto-context to handle create parameters (v5)")
> Cc: Faith Ekstrand <faith.ekstrand@collabora.com>
> Cc: Simona Vetter <simona.vetter@ffwll.ch>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v5.15+
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_context.c | 22 +++++++++++++--------
>  1 file changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index aeafe1742d30..87fce2adfeef 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -769,8 +769,8 @@ static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
>  		struct intel_engine_cs *engine;
>  
>  		if (copy_from_user(&ci, &user->engines[n], sizeof(ci))) {
> -			kfree(set.engines);
> -			return -EFAULT;
> +			err = -EFAULT;
> +			goto err;
>  		}
>  
>  		memset(&set.engines[n], 0, sizeof(set.engines[n]));
> @@ -786,8 +786,8 @@ static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
>  			drm_dbg(&i915->drm,
>  				"Invalid engine[%d]: { class:%d, instance:%d }\n",
>  				n, ci.engine_class, ci.engine_instance);
> -			kfree(set.engines);
> -			return -ENOENT;
> +			err = -ENOENT;
> +			goto err;
>  		}
>  
>  		set.engines[n].type = I915_GEM_ENGINE_TYPE_PHYSICAL;
> @@ -800,15 +800,21 @@ static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
>  					   set_proto_ctx_engines_extensions,
>  					   ARRAY_SIZE(set_proto_ctx_engines_extensions),
>  					   &set);
> -	if (err) {
> -		kfree(set.engines);
> -		return err;
> -	}
> +	if (err)
> +		goto err_extensions;
>  
>  	pc->num_user_engines = set.num_engines;
>  	pc->user_engines = set.engines;
>  
>  	return 0;
> +
> +err_extensions:
> +	for (n = 0; n < set.num_engines; n++)
> +		kfree(set.engines[n].siblings);
> +err:
> +	kfree(set.engines);
> +
> +	return err;
>  }
>  
>  static int set_proto_ctx_sseu(struct drm_i915_file_private *fpriv,