RE: [RFC PATCH] packet: mark ring entry as in-use inside spin_lock to prevent RX ring overrun

["Jon Rosen (jrosen)" <jrosen@cisco.com>]

> > diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> > index e0f3f4a..264d7b2 100644
> > --- a/net/packet/af_packet.c
> > +++ b/net/packet/af_packet.c
> > @@ -2287,6 +2287,15 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
> >  		if (po->stats.stats1.tp_drops)
> >  			status |= TP_STATUS_LOSING;
> >  	}
> > +
> > +        /*
> > +         * Mark this entry as TP_STATUS_IN_PROGRESS to prevent other
> > +         * kernel threads from re-using this same entry.
> > +         */
> > +#define TP_STATUS_IN_PROGRESS TP_STATUS_LOSING
> > +	if (po->tp_version <= TPACKET_V2)
> > +            __packet_set_status(po, h.raw, TP_STATUS_IN_PROGRESS);
> > +
> >  	po->stats.stats1.tp_packets++;
> >  	if (copy_skb) {
> >  		status |= TP_STATUS_COPY;
> 
> This patch looks correct. Please resend it with proper signed-off-by
> and with a kernel code indenting style (tabs).  Is this bug present
> since the beginning of af_packet and multiqueue devices or did it get
> introduced in some previous kernel?

Sorry about the tabs, I'll fix that and try to figure out what I did wrong with
the signed-off-by.

I've looked back as far as I could find online (2.6.11) and it would appear that
this bug has always been there.

Thanks, jon.