Re: [PATCH net-next v11 4/5] net: dsa: motorcomm: Add LED support

[Andrew Lunn]

> > Would an "echo netdev > /sys/class/leds/<led>/trigger" racing with switch
> > unbind, or with the dsa_tree_setup() error path, touch a freed
> > net_device here? Would removing the LEDs per port before the netdevs go
> > away, or validating dp->user under rtnl_lock, avoid that?
> >
> > > @@ -4581,6 +4589,12 @@ static int yt921x_dsa_setup(struct dsa_switch *ds)
> > >       if (res)
> > >               return res;
> > >
> > > +#if IS_ENABLED(CONFIG_NET_DSA_YT921X_LEDS)
> > > +     res = yt921x_leds_setup(priv);
> > > +     if (res)
> > > +             dev_warn(dev, "Failed to setup LEDs: %d\n", res);
> > > +#endif
> > > +
> 
> Just a question: I don't see any protection against this in other DSA
> led drivers, like mv88e6 or qca8k.

Registering the LEDs uses devm_ so the life of the LEDs is the life of
the chip. The LED trigger does however take a reference on the network
device, so it should not be possible for it to disappear while the
trigger is still bound to it.

	Andrew