Re: [PATCH v6 04/22] drm/panfrost: Fix shrinker list corruption by madvise IOCTL

[Steven Price]

On 27/05/2022 00:50, Dmitry Osipenko wrote:
> Calling madvise IOCTL twice on BO causes memory shrinker list corruption
> and crashes kernel because BO is already on the list and it's added to
> the list again, while BO should be removed from from the list before it's
> re-added. Fix it.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support")
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>

Reviewed-by: Steven Price <steven.price@xxxxxxx>

> ---
>  drivers/gpu/drm/panfrost/panfrost_drv.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 087e69b98d06..b1e6d238674f 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -433,8 +433,8 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
>  
>  	if (args->retained) {
>  		if (args->madv == PANFROST_MADV_DONTNEED)
> -			list_add_tail(&bo->base.madv_list,
> -				      &pfdev->shrinker_list);
> +			list_move_tail(&bo->base.madv_list,
> +				       &pfdev->shrinker_list);
>  		else if (args->madv == PANFROST_MADV_WILLNEED)
>  			list_del_init(&bo->base.madv_list);
>  	}