On Wed, Jan 19, 2022 at 10:03 AM Kenny Yu <kennyyu@xxxxxx> wrote:
>
> +BPF_CALL_5(bpf_access_process_vm, void *, dst, u32, size,
> + const void __user *, user_ptr, struct task_struct *, tsk,
> + u32, flags)
> +{
> + /* flags is not used yet */
> + return access_process_vm(tsk, (unsigned long)user_ptr, dst, size, 0);
> +}
Though the 'flags' argument is unused the helper has to check
that it's zero and return -EINVAL otherwise.
If we don't do this we won't be able to change the behavior later
due to backward compatibility.
