* [PATCH] drm/mediatek: Clean dangling pointer on bind error path
@ 2022-11-21 22:37 Nícolas F. R. A. Prado
2022-11-22 9:12 ` AngeloGioacchino Del Regno
0 siblings, 1 reply; 2+ messages in thread
From: Nícolas F. R. A. Prado @ 2022-11-21 22:37 UTC (permalink / raw)
To: Chun-Kuang Hu
Cc: kernel, AngeloGioacchino Del Regno, Nancy . Lin,
Nícolas F. R. A. Prado, Daniel Vetter, David Airlie,
Matthias Brugger, Philipp Zabel, dri-devel, linux-arm-kernel,
linux-kernel, linux-mediatek
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] drm/mediatek: Clean dangling pointer on bind error path
2022-11-21 22:37 [PATCH] drm/mediatek: Clean dangling pointer on bind error path Nícolas F. R. A. Prado
@ 2022-11-22 9:12 ` AngeloGioacchino Del Regno
0 siblings, 0 replies; 2+ messages in thread
From: AngeloGioacchino Del Regno @ 2022-11-22 9:12 UTC (permalink / raw)
To: Nícolas F. R. A. Prado, Chun-Kuang Hu
Cc: kernel, Nancy . Lin, Daniel Vetter, David Airlie,
Matthias Brugger, Philipp Zabel, dri-devel, linux-arm-kernel,
linux-kernel, linux-mediatek
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;
> }
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-11-21 22:37 [PATCH] drm/mediatek: Clean dangling pointer on bind error path Nícolas F. R. A. Prado
2022-11-22 9:12 ` AngeloGioacchino Del Regno
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