mtk_drm_bind() can fail, in which case drm_dev_put() is called,
destroying the drm_device object. However a pointer to it was still
being held in the private object, and that pointer would be passed along
to DRM in mtk_drm_sys_prepare() if a suspend were triggered at that
point, resulting in a panic. Clean the pointer when destroying the
object in the error path to prevent this from happening.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

---

 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 39a42dc8fb85..a21ff1b3258c 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -514,6 +514,7 @@ static int mtk_drm_bind(struct device *dev)
 err_deinit:
 	mtk_drm_kms_deinit(drm);
 err_free:
+	private->drm = NULL;
 	drm_dev_put(drm);
 	return ret;
 }
-- 
2.38.1

Il 21/11/22 23:37, Nícolas F. R. A. Prado ha scritto:
> mtk_drm_bind() can fail, in which case drm_dev_put() is called,
> destroying the drm_device object. However a pointer to it was still
> being held in the private object, and that pointer would be passed along
> to DRM in mtk_drm_sys_prepare() if a suspend were triggered at that
> point, resulting in a panic. Clean the pointer when destroying the
> object in the error path to prevent this from happening.
> 
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> 

Fixes tag please! :-)

Cheers,
Angelo

> ---
> 
>   drivers/gpu/drm/mediatek/mtk_drm_drv.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 39a42dc8fb85..a21ff1b3258c 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -514,6 +514,7 @@ static int mtk_drm_bind(struct device *dev)
>   err_deinit:
>   	mtk_drm_kms_deinit(drm);
>   err_free:
> +	private->drm = NULL;
>   	drm_dev_put(drm);
>   	return ret;
>   }