[Intel-gfx] [PATCH v1] drm/i915/guc: Fix a memory leak where guc->execbuf_client is not freed

[Dave Gordon]

On 12/01/16 23:17, yu.dai at intel.com wrote:
> From: Alex Dai <yu.dai at intel.com>
>
> During driver unloading, the guc_client created for command submission
> needs to be released to avoid memory leak.
>
> The struct_mutex needs to be held before tearing down GuC.
>
> v1: Move i915_guc_submission_disable out of i915_guc_submission_fini and
>      take struct_mutex lock before release GuC client. (Dave Gordon)

You don't seem to have implemented all the points I mentioned? I think 
you want:

drivers/gpu/drm/i915/intel_guc_loader.c:
@@ -445,6 +445,7 @@ int intel_guc_ucode_load(struct drm_device *dev)

         direct_interrupts_to_host(dev_priv);
         i915_guc_submission_disable(dev);
+       i915_guc_submission_fini(dev);

Optional, but cleaner. We called i915_guc_submission_init() earlier in 
this function, so we should call i915_guc_submission_fini() in the 
failure path. That way, we either succeed, or leave the system state 
unchanged, NOT leaving extra objects allocated.

         return err;
  }

@@ -561,10 +562,12 @@ static void guc_fw_fetch(struct drm_device *dev, 
struct intel_guc_fw *guc_fw)
  	DRM_ERROR("Failed to fetch GuC firmware from %s (error %d)\n",
  		  guc_fw->guc_fw_path, err);

+	mutex_lock(&dev->struct_mutex);
  	obj = guc_fw->guc_fw_obj;
  	if (obj)
  		drm_gem_object_unreference(&obj->base);
  	guc_fw->guc_fw_obj = NULL;
+	mutex_unlock(&dev->struct_mutex);

This is the locking that needs to be added to the failure path.
This is required *in addition to* the locking reorganisation below.

> Signed-off-by: Alex Dai <yu.dai at intel.com>
>
> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
> index d20788f..70fa8f5 100644
> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
> @@ -631,10 +631,11 @@ void intel_guc_ucode_fini(struct drm_device *dev)
>   	struct drm_i915_private *dev_priv = dev->dev_private;
>   	struct intel_guc_fw *guc_fw = &dev_priv->guc.guc_fw;
>
> +	mutex_lock(&dev->struct_mutex);
>   	direct_interrupts_to_host(dev_priv);
> +	i915_guc_submission_disable(dev);
>   	i915_guc_submission_fini(dev);
>
> -	mutex_lock(&dev->struct_mutex);
>   	if (guc_fw->guc_fw_obj)
>   		drm_gem_object_unreference(&guc_fw->guc_fw_obj->base);
>   	guc_fw->guc_fw_obj = NULL;

This bit is fine, but incomplete without the other changes above.

.Dave.