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

[Christophe JAILLET]

Le 20/12/2025 à 20:01, Jerry Wu a écrit :
> Commit 15faa1f67ab4 ("lan966x: Fix crash when adding interface under a lag")
> fixed a similar issue in the lan966x driver caused by a NULL pointer dereference.
> The ocelot_set_aggr_pgids() function in the ocelot driver has similar logic
> and is susceptible to the same crash.
>
> This issue specifically affects the ocelot_vsc7514.c frontend, which leaves
> unused ports as NULL pointers. The felix_vsc9959.c frontend is unaffected as
> it uses the DSA framework which registers all ports.
>
> Fix this by checking if the port pointer is valid before accessing it.
>
> Fixes: 528d3f190c98 ("net: mscc: ocelot: drop the use of the "lags" array")
> Signed-off-by: Jerry Wu <w.7erry@xxxxxxxxxxx>
> ---
>   drivers/net/ethernet/mscc/ocelot.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
> index 08bee56aea35..6f917fd7af4d 100644
> --- a/drivers/net/ethernet/mscc/ocelot.c
> +++ b/drivers/net/ethernet/mscc/ocelot.c
> @@ -2307,14 +2307,16 @@ static void ocelot_set_aggr_pgids(struct ocelot *ocelot)
>   
>   	/* Now, set PGIDs for each active LAG */
>   	for (lag = 0; lag < ocelot->num_phys_ports; lag++) {
> -		struct net_device *bond = ocelot->ports[lag]->bond;
> +		struct ocelot_port *ocelot_port = ocelot->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 (!ocelot_port || !ocelot_port->bond || (visited & BIT(lag)))

ok, but it would be clearer if this was a v3 of the patch.

It is also usually welcomed to explain what has changed between versions 
below the ---.

CJ

>   			continue;
>   
> +		bond = ocelot_port->bond;
>   		bond_mask = ocelot_get_bond_mask(ocelot, bond);
>   
>   		for_each_set_bit(port, &bond_mask, ocelot->num_phys_ports) {