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

[Thomas Monjalon <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>]

2015-02-25 09:52, Liang, Cunming:
> From: Thomas Monjalon [mailto:thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org]
> > 2015-02-25 00:57, Liang, Cunming:
> > > From: John W. Linville [mailto:linville-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org]
> > > > On Fri, Feb 20, 2015 at 11:19:59AM +0100, Thomas Monjalon wrote:
> > > > > 2015-02-12 17:08, Cunming Liang:
> > > > > > --- 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;'.
> > 
> > Yes understood, but it is already initialized to NULL before calling
> > rte_pmd_init_internals():
> > http://dpdk.org/browse/dpdk/tree/lib/librte_pmd_af_packet/rte_eth_af_packet
> > .c#n706
> [LCM] I see, it's complained by klocwork.
> So either adding 'internals=NULL' or adding some comments helps to avoid checking again on the next scanning.
> How do you think ?

No, we don't have to pollute the code for a tool.
You should check how to disable this false positive in your tool.