[PATCH] drm: Fix writeback_job leak when state is check only or check failed

[Maarten Lankhorst]

Hey

Op 21-02-2019 om 12:14 schreef james qian wang (Arm Technology China):
> The writeback job will not be added to writeback queue if the state is
> check only or check failed, to avoid leak, need to cleanup writeback job
> in connector_destroy_state if the job existed.
>
> Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang at arm.com>

Is writeback_job in the conn_state set to null somewhere? I'm worried we might end up freeing writeback_job twice on success.

~Maarten

>  drivers/gpu/drm/drm_atomic_state_helper.c |  4 ++++
>  drivers/gpu/drm/drm_writeback.c           | 21 ++++++++++++++++++---
>  2 files changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
> index 4985384e51f6..6a8e414233de 100644
> --- a/drivers/gpu/drm/drm_atomic_state_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
> @@ -28,6 +28,7 @@
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_plane.h>
>  #include <drm/drm_connector.h>
> +#include <drm/drm_writeback.h>
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_device.h>
>  
> @@ -407,6 +408,9 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_duplicate_state);
>  void
>  __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
>  {
> +	if (state->writeback_job)
> +		drm_writeback_cleanup_job(state->writeback_job);
> +
>  	if (state->crtc)
>  		drm_connector_put(state->connector);
>  
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index c20e6fe00cb3..486121150eaa 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -268,6 +268,22 @@ void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,
>  }
>  EXPORT_SYMBOL(drm_writeback_queue_job);
>  
> +/**
> + * drm_writeback_cleanup_job - cleanup a writeback job
> + * @job: The job to cleanup
> + */
> +void drm_writeback_cleanup_job(struct drm_writeback_job *job)
> +{
> +	if (job->fb)
> +		drm_framebuffer_put(job->fb);
> +
> +	if (job->out_fence)
> +		dma_fence_put(job->out_fence);
> +
> +	kfree(job);
> +}
> +EXPORT_SYMBOL(drm_writeback_cleanup_job);
> +
>  /*
>   * @cleanup_work: deferred cleanup of a writeback job
>   *
> @@ -280,11 +296,9 @@ static void cleanup_work(struct work_struct *work)
>  	struct drm_writeback_job *job = container_of(work,
>  						     struct drm_writeback_job,
>  						     cleanup_work);
> -	drm_framebuffer_put(job->fb);
> -	kfree(job);
> +	drm_writeback_cleanup_job(job);
>  }
>  
> -
>  /**
>   * drm_writeback_signal_completion - Signal the completion of a writeback job
>   * @wb_connector: The writeback connector whose job is complete
> @@ -319,6 +333,7 @@ drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,
>  				dma_fence_set_error(job->out_fence, status);
>  			dma_fence_signal(job->out_fence);
>  			dma_fence_put(job->out_fence);
> +			job->out_fence = NULL;
>  		}
>  	}
>  	spin_unlock_irqrestore(&wb_connector->job_lock, flags);