A MAC address must be unique among all the macvlan devices with the same
lower device. The only exception is the passthru [sic] mode,
which shares the lower device address.
When duplicate addresses are detected, EBUSY is returned when bringing
the interface up:
# ip link add macvlan0 link eth
From: Matteo Croce
Date: Sat, 1 Dec 2018 00:26:27 +0100
> A MAC address must be unique among all the macvlan devices with the same
> lower device. The only exception is the passthru [sic] mode,
> which shares the lower device address.
>
> When duplicate addresses are detected, EBUSY is returned
