Subject: Re: [PATCH] net: mellanox: mlxsw: fix error return code of mlxsw_sp_router_nve_promote_decap()

From: Ido Schimmel <[email-masked]>
Date: Sun, 7 Mar 2021 10:26:52 +0200

On Sat, Mar 06, 2021 at 03:32:39PM +0100, Heiner Kallweit wrote:
> On 06.03.2021 15:07, Jia-Ju Bai wrote:
> > When fib_entry is NULL, no error return code of
> > mlxsw_sp_router_nve_promote_decap() is assigned.
> > To fix this bug, err is assigned with -EINVAL in this case.
> > 
> Again, are you sure this is a bug? To me it looks like it is
> intentional to not return an error code if fib_entry is NULL.
> Please don't blindly trust the robot results, there may
> always be false positives.

Yes, it is OK not to return an error. There is even a comment above the
call to mlxsw_sp_router_ip2me_fib_entry_find():

/* It is valid to create a tunnel with a local IP and only later
 * assign this IP address to a local interface
 */

> 
> > Reported-by: TOTE Robot <[email-masked]>
> > Signed-off-by: Jia-Ju Bai <[email-masked]>
> > ---
> >  drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> > index 9ce90841f92d..7b260e25df1b 100644
> > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> > @@ -1981,8 +1981,10 @@ int mlxsw_sp_router_nve_promote_decap(struct mlxsw_sp *mlxsw_sp, u32 ul_tb_id,
> >  	fib_entry = mlxsw_sp_router_ip2me_fib_entry_find(mlxsw_sp, ul_tb_id,
> >  							 ul_proto, ul_sip,
> >  							 type);
> > -	if (!fib_entry)
> > +	if (!fib_entry) {
> > +		err = -EINVAL;
> >  		goto out;
> > +	}
> >  
> >  	fib_entry->decap.tunnel_index = tunnel_index;
> >  	fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_NVE_DECAP;
> > 
>