netdev - Re: [PATCHv2 iproute2 1/2] lib/libnetlink: re malloc buff if size is not enough

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Date:   Tue, 19 Sep 2017 13:48:08 +0200
From:   Michal Kubecek <mkubecek@...e.cz>
To:     Hangbin Liu <liuhangbin@...il.com>
Cc:     netdev@...r.kernel.org,
        Stephen Hemminger <stephen@...workplumber.org>,
        Phil Sutter <phil@....cc>
Subject: Re: [PATCHv2 iproute2 1/2] lib/libnetlink: re malloc buff if size is
 not enough

On Tue, Sep 19, 2017 at 11:05:20AM +0800, Hangbin Liu wrote:
> On Mon, Sep 18, 2017 at 09:55:05AM +0200, Michal Kubecek wrote:
> > > @@ -471,19 +516,23 @@ int rtnl_dump_filter_l(struct rtnl_handle *rth,
> > >  
> > >  				if (h->nlmsg_type == NLMSG_ERROR) {
> > >  					rtnl_dump_error(rth, h);
> > > +					free(buf);
> > >  					return -1;
> > >  				}
> > >  
> > >  				if (!rth->dump_fp) {
> > >  					err = a->filter(&nladdr, h, a->arg1);
> > > -					if (err < 0)
> > > +					if (err < 0) {
> > > +						free(buf);
> > >  						return err;
> > > +					}
> > >  				}
> > >  
> > >  skip_it:
> > >  				h = NLMSG_NEXT(h, msglen);
> > >  			}
> > >  		}
> > > +		free(buf);
> > 
> > We only free the last buffer returned by rtnl_recvmsg() this way.
> > IMHO this free(buf) should be moved inside the loop.
> 
> Do you mean the outside while loop or the for loop? I think we could
> not put it inside the for loop, because we may need the buf multi
> times based on arg.

Sorry for the confusion, you are right, this part is correct. I misread
the indentation.

Michal Kubecek