Re: [PATCH net-next] tuntap: Fallback to automq on TUNSETSTEERINGEBPF prog negative return

Michael S. Tsirkin
2019-09-25T10:33:54Z

On Sun, Sep 22, 2019 at 03:46:19PM -0700, Matt Cover wrote:
> Unless of course we can simply state via
> documentation that any negative return
> for which a define doesn't exist is
> undefined behavior. In which case,
> there is no old vs new behavior and
> no need for an ioctl. Simply the
> understanding provided by the
> documentation.

Unfortunately this isn't sufficient: software can easily return a wrong
value by mistake, and become dependent on an undefined behaviour.

--
MST