Re: [PATCH 10/14] accel/ivpu: Fix locking order in ivpu_cmdq_destroy_ioctl

[Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>]

Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>

On 1/7/2025 6:32 PM, Maciej Falkowski wrote:
> From: Karol Wachowski <karol.wachowski@intel.com>
> 
> Fix deadlock caused by inversed locking order in ivpu_job_submit()
> and ivpu_cmdq_destroy_ioctl(). Both functions operate locking
> file_priv->lock and submitted_jobs_lock.
> 
> Unlock file_priv->lock in ivpu_cmdq_destroy_ioctl() before calling
> ivpu_cmdq_abort_all_jobs() function which locks submitted_jobs_lock.
> That way locking order is maintained:
>  1) global submitted_jobs_lock first
>  2) per context file_priv->lock second
> 
> Signed-off-by: Karol Wachowski <karol.wachowski@intel.com>
> Signed-off-by: Maciej Falkowski <maciej.falkowski@linux.intel.com>
> ---
>  drivers/accel/ivpu/ivpu_job.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/accel/ivpu/ivpu_job.c b/drivers/accel/ivpu/ivpu_job.c
> index 37ea92eb4b25..c694822a14bf 100644
> --- a/drivers/accel/ivpu/ivpu_job.c
> +++ b/drivers/accel/ivpu/ivpu_job.c
> @@ -883,7 +883,7 @@ int ivpu_cmdq_destroy_ioctl(struct drm_device *dev, void *data, struct drm_file
>  	struct drm_ivpu_cmdq_destroy *args = data;
>  	struct ivpu_cmdq *cmdq;
>  	u32 cmdq_id;
> -	int ret = 0;
> +	int ret;
>  
>  	if (!ivpu_is_capable(vdev, DRM_IVPU_CAP_MANAGE_CMDQ))
>  		return -ENODEV;
> @@ -893,13 +893,16 @@ int ivpu_cmdq_destroy_ioctl(struct drm_device *dev, void *data, struct drm_file
>  	cmdq = xa_load(&file_priv->cmdq_xa, args->cmdq_id);
>  	if (!cmdq || cmdq->is_legacy) {
>  		ret = -ENOENT;
> -		goto unlock;
> +		goto err_unlock;
>  	}
>  
>  	cmdq_id = cmdq->id;
>  	ivpu_cmdq_destroy(file_priv, cmdq);
> +	mutex_unlock(&file_priv->lock);
>  	ivpu_cmdq_abort_all_jobs(vdev, file_priv->ctx.id, cmdq_id);
> -unlock:
> +	return 0;
> +
> +err_unlock:
>  	mutex_unlock(&file_priv->lock);
>  	return ret;
>  }