Re: [PATCH] drm:vkms: Add NULL value after free function In function vkms_exit, after kfree(default_config), give specific NULL value to pointer default_config to avoid wild pointer.

[Daniel Vetter]

On Wed, May 12, 2021 at 07:55:54PM +0800, Hao Peng wrote:
> Signed-off-by: Hao Peng <penghaob@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/vkms/vkms_drv.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index 2173b82606f6..6c63201db5d0 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -227,6 +227,7 @@ static void __exit vkms_exit(void)
>  		vkms_destroy(default_config);
>  
>  	kfree(default_config);
> +	default_config = NULL;

This is the last thing before the module us unloaded, which means no one
can access default_config anymore. So also no point in clearing it.
-Daniel

>  }
>  
>  module_init(vkms_init);
> -- 
> 2.20.1
> 
> 
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch