Re: [dpdk-dev] [PATCH v1] afpacket: fix critical issue reported by klocwork

["Liang, Cunming" <cunming.liang@intel.com>]

> -----Original Message-----
> From: John W. Linville [mailto:linville@tuxdriver.com]
> Sent: Saturday, February 21, 2015 2:39 AM
> To: Thomas Monjalon
> Cc: Liang, Cunming; dev@dpdk.org; John Linville
> Subject: Re: [dpdk-dev] [PATCH v1] afpacket: fix critical issue reported by
> klocwork
> 
> On Fri, Feb 20, 2015 at 11:19:59AM +0100, Thomas Monjalon wrote:
> > Hi Cunming,
> >
> > You would have more chance to have a review by CC'ing John.
> > I checked your patch and have a comment below.
> >
> > 2015-02-12 17:08, Cunming Liang:
> > > Klocwork report 'req' might be used uninitialized.
> > > In some cases it can 'goto error' when '*internals' not been set.
> > > The result is unexpected checking the value of '*internals'.
> > >
> > > Signed-off-by: Cunming Liang <cunming.liang@intel.com>
> > > ---
> > >  lib/librte_pmd_af_packet/rte_eth_af_packet.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/lib/librte_pmd_af_packet/rte_eth_af_packet.c
> b/lib/librte_pmd_af_packet/rte_eth_af_packet.c
> > > index 1ffe1cd..185607d 100644
> > > --- a/lib/librte_pmd_af_packet/rte_eth_af_packet.c
> > > +++ b/lib/librte_pmd_af_packet/rte_eth_af_packet.c
> > > @@ -439,13 +439,15 @@ rte_pmd_init_internals(const char *name,
> > >  	size_t ifnamelen;
> > >  	unsigned k_idx;
> > >  	struct sockaddr_ll sockaddr;
> > > -	struct tpacket_req *req;
> > > +	struct tpacket_req *req = NULL;
> >
> > If *internals is set to NULL, there should be no case where req used
> > and undefined.
[LCM] Agree, so that's why I add '*internals = NULL' below as well.
> 
> I agree -- it looks to me like req is protected by checking for
> *internals == NULL.  I don't think this patch is necessary.
[LCM] The major piece of the patch is add setting for '*internals=NULL;'.
> 
> > >  	struct pkt_rx_queue *rx_queue;
> > >  	struct pkt_tx_queue *tx_queue;
> > >  	int rc, qsockfd, tpver, discard;
> > >  	unsigned int i, q, rdsize;
> > >  	int fanout_arg __rte_unused, bypass __rte_unused;
> > >
> > > +	*internals = NULL;
> > > +
> > >  	for (k_idx = 0; k_idx < kvlist->count; k_idx++) {
> > >  		pair = &kvlist->pairs[k_idx];
> > >  		if (strstr(pair->key, ETH_AF_PACKET_IFACE_ARG) != NULL)
> > >
> >
> >
> >
> >
> 
> --
> John W. Linville		Someday the world will need a hero, and you
> linville@tuxdriver.com			might be all we have.  Be ready.