Re: [PATCH] net/ncsi: Use real net-device for response handler

[Samuel Mendoza-Jonas <sam@mendozajonas.com>]

On Tue, 2020-12-22 at 06:13 +0000, Joel Stanley wrote:
> On Sun, 20 Dec 2020 at 12:40, John Wang <
> wangzhiqiang.bj@bytedance.com> wrote:
> > 
> > When aggregating ncsi interfaces and dedicated interfaces to bond
> > interfaces, the ncsi response handler will use the wrong net device
> > to
> > find ncsi_dev, so that the ncsi interface will not work properly.
> > Here, we use the net device registered to packet_type to fix it.
> > 
> > Fixes: 138635cc27c9 ("net/ncsi: NCSI response packet handler")
> > Signed-off-by: John Wang <wangzhiqiang.bj@bytedance.com>
> 
> Can you show me how to reproduce this?
> 
> I don't know the ncsi or net code well enough to know if this is the
> correct fix. If you are confident it is correct then I have no
> objections.

This looks like it is probably right; pt->dev will be the original
device from ncsi_register_dev(), if a response comes in to
ncsi_rcv_rsp() associated with a different device then the driver will
fail to find the correct ncsi_dev_priv. An example of the broken case
would be good to see though.

Cheers,
Sam

> 
> Cheers,
> 
> Joel
> 
> > ---
> >  net/ncsi/ncsi-rsp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/net/ncsi/ncsi-rsp.c b/net/ncsi/ncsi-rsp.c
> > index a94bb59793f0..60ae32682904 100644
> > --- a/net/ncsi/ncsi-rsp.c
> > +++ b/net/ncsi/ncsi-rsp.c
> > @@ -1120,7 +1120,7 @@ int ncsi_rcv_rsp(struct sk_buff *skb, struct
> > net_device *dev,
> >         int payload, i, ret;
> > 
> >         /* Find the NCSI device */
> > -       nd = ncsi_find_dev(dev);
> > +       nd = ncsi_find_dev(pt->dev);
> >         ndp = nd ? TO_NCSI_DEV_PRIV(nd) : NULL;
> >         if (!ndp)
> >                 return -ENODEV;
> > --
> > 2.25.1
> >