[Nouveau] [PATCH] nouveau/u_memcpya: fix NULL vs error pointer bug

[Danilo Krummrich]

Hi Dan,

On 9/15/23 14:59, Dan Carpenter wrote:
> The u_memcpya() function is supposed to return error pointers on
> error.  Returning NULL will lead to an Oops.
> 
> Fixes: 68132cc6d1bc ("nouveau/u_memcpya: use vmemdup_user")
> Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>
> ---
>   drivers/gpu/drm/nouveau/nouveau_drv.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
> index 3666a7403e47..52a708a98915 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_drv.h
> +++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
> @@ -193,7 +193,7 @@ u_memcpya(uint64_t user, unsigned int nmemb, unsigned int size)
>   	size_t bytes;
>   
>   	if (unlikely(check_mul_overflow(nmemb, size, &bytes)))
> -		return NULL;
> +		return ERR_PTR(-ENOMEM);

I plan to replace this function with an upcoming vmemdup_array_user() helper,
which returns -EOVERFLOW instead, hence mind using that?

Unless you disagree, no need to resubmit the patch, I can change it before applying
the patch.

- Danilo

>   	return vmemdup_user(userptr, bytes);
>   }
>