Re: [PATCH net v2] lan966x: Fix crash when adding interface under a lag

[Horatiu Vultur]

The 02/09/2024 13:52, Jakub Kicinski wrote:

Hi Jakub,

> 
> On Tue, 6 Feb 2024 13:30:54 +0100 Horatiu Vultur wrote:
> >       for (lag = 0; lag < lan966x->num_phys_ports; ++lag) {
> > -             struct net_device *bond = lan966x->ports[lag]->bond;
> > +             struct lan966x_port *port = lan966x->ports[lag];
> >               int num_active_ports = 0;
> > +             struct net_device *bond;
> >               unsigned long bond_mask;
> >               u8 aggr_idx[16];
> >
> > -             if (!bond || (visited & BIT(lag)))
> > +             if (!port || !port->bond || (visited & BIT(lag)))
> >                       continue;
> >
> > +             bond = port->bond;
> >               bond_mask = lan966x_lag_get_mask(lan966x, bond);
> >
> >               for_each_set_bit(p, &bond_mask, lan966x->num_phys_ports) {
> >                       struct lan966x_port *port = lan966x->ports[p];
> >
> > +                     if (!port)
> > +                             continue;
> 
> Why would lan966x_lag_get_mask() set a bit for a port that doesn't
> exist? Earlier check makes sense. This one seems too defensive.

You are right, the lan966x_lag_get_mask() will not set a bit for a port
that doesn't exist[1]. Therefore this check is not needed.

[1] https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/microchip/lan966x/lan966x_lag.c#L354

> --
> pw-bot: cr

-- 
/Horatiu