[Public]
Thanks for your suggestion, Robin. Do you agree with this as well, Christian and Xinhui?
Regards,
Guchun
-----Original Message-----
From: Robin Murphy <robin.murphy@xxxxxxx>
Sent: Saturday, September 11, 2021 2:25 AM
To: Chen, Guchun <Guchun.Chen@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; Koenig, Christian <Christian.Koenig@xxxxxxx>; Pan, Xinhui <Xinhui.Pan@xxxxxxx>; Deucher, Alexander <Alexander.Deucher@xxxxxxx>
Cc: Shi, Leslie <Yuliang.Shi@xxxxxxx>
Subject: Re: [PATCH] drm/ttm: add a WARN_ON in ttm_set_driver_manager when array bounds (v2)
On 2021-09-10 11:09, Guchun Chen wrote:
> Vendor will define their own memory types on top of TTM_PL_PRIV, but
> call ttm_set_driver_manager directly without checking mem_type value
> when setting up memory manager. So add such check to aware the case
> when array bounds.
>
> v2: lower check level to WARN_ON
>
> Signed-off-by: Leslie Shi <Yuliang.Shi@xxxxxxx>
> Signed-off-by: Guchun Chen <guchun.chen@xxxxxxx>
> ---
> include/drm/ttm/ttm_device.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/drm/ttm/ttm_device.h
> b/include/drm/ttm/ttm_device.h index 07d722950d5b..aa79953c807c 100644
> --- a/include/drm/ttm/ttm_device.h
> +++ b/include/drm/ttm/ttm_device.h
> @@ -291,6 +291,7 @@ ttm_manager_type(struct ttm_device *bdev, int mem_type)
> static inline void ttm_set_driver_manager(struct ttm_device *bdev, int type,
> struct ttm_resource_manager *manager)
> {
> + WARN_ON(type >= TTM_NUM_MEM_TYPES);
Nit: I know nothing about this code, but from the context alone it would seem sensible to do
if (WARN_ON(type >= TTM_NUM_MEM_TYPES))
return;
to avoid making the subsequent assignment when we *know* it's invalid and likely to corrupt memory.
Robin.
> bdev->man_drv[type] = manager;
> }
>
>
