linux-kernel - Re: [PATCH 02/10] Revert "drm/msm: Fix failure paths in msm_drm

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Message-ID: <74e44866-1de6-e74c-7d06-7189fe328aa5@linaro.org>
Date:   Tue, 28 Mar 2023 15:49:32 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Johan Hovold <johan+linaro@...nel.org>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc:     Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Akhil P Oommen <quic_akhilpo@...cinc.com>
Subject: Re: [PATCH 02/10] Revert "drm/msm: Fix failure paths in
 msm_drm_init()"

On 06/03/2023 12:07, Johan Hovold wrote:
> This reverts commit 8636500300a01740d92b345c680b036b94555b1b.
> 
> A recent commit tried to address a drm device leak in the early
> msm_drm_uninit() error paths but ended up making things worse.
> 
> Specifically, it moved the drm device reference put in msm_drm_uninit()
> to msm_drm_init() which means that the drm would now be leaked on normal
> unbind.
> 
> For reasons that were never spelled out, it also added kms NULL pointer
> checks to a couple of helper functions that had nothing to do with the
> paths modified by the patch.
> 
> Instead of trying to salvage this incrementally, let's revert the bad
> commit so that clean and backportable fixes can be added in its place.
> 
> Fixes: 8636500300a0 ("drm/msm: Fix failure paths in msm_drm_init()")
> Cc: Akhil P Oommen <quic_akhilpo@...cinc.com>
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>

Ok, let's do it this way

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

> ---
>   drivers/gpu/drm/msm/disp/msm_disp_snapshot.c |  3 ---
>   drivers/gpu/drm/msm/msm_drv.c                | 11 ++++-------
>   2 files changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c b/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
> index b73031cd48e4..e75b97127c0d 100644
> --- a/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
> +++ b/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
> @@ -129,9 +129,6 @@ void msm_disp_snapshot_destroy(struct drm_device *drm_dev)
>   	}
>   
>   	priv = drm_dev->dev_private;
> -	if (!priv->kms)
> -		return;
> -
>   	kms = priv->kms;
>   
>   	if (kms->dump_worker)
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index b7f5a78eadd4..9ded384acba4 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -150,9 +150,6 @@ static void msm_irq_uninstall(struct drm_device *dev)
>   	struct msm_drm_private *priv = dev->dev_private;
>   	struct msm_kms *kms = priv->kms;
>   
> -	if (!priv->kms)
> -		return;
> -
>   	kms->funcs->irq_uninstall(kms);
>   	if (kms->irq_requested)
>   		free_irq(kms->irq, dev);
> @@ -270,6 +267,8 @@ static int msm_drm_uninit(struct device *dev)
>   	component_unbind_all(dev, ddev);
>   
>   	ddev->dev_private = NULL;
> +	drm_dev_put(ddev);
> +
>   	destroy_workqueue(priv->wq);
>   
>   	return 0;
> @@ -442,12 +441,12 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
>   
>   	ret = msm_init_vram(ddev);
>   	if (ret)
> -		goto err_drm_dev_put;
> +		return ret;
>   
>   	/* Bind all our sub-components: */
>   	ret = component_bind_all(dev, ddev);
>   	if (ret)
> -		goto err_drm_dev_put;
> +		return ret;
>   
>   	dma_set_max_seg_size(dev, UINT_MAX);
>   
> @@ -542,8 +541,6 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
>   
>   err_msm_uninit:
>   	msm_drm_uninit(dev);
> -err_drm_dev_put:
> -	drm_dev_put(ddev);
>   	return ret;
>   }
>   

-- 
With best wishes
Dmitry