RE: [EXT] [PATCH 3/8] trace: fix leak with regexp

[Sunil Kumar Kori <skori@marvell.com>]

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Friday, September 23, 2022 12:05 PM
> To: Sunil Kumar Kori <skori@marvell.com>
> Cc: dev@dpdk.org; stable@dpdk.org; Jerin Jacob Kollanukkaran
> <jerinj@marvell.com>
> Subject: Re: [EXT] [PATCH 3/8] trace: fix leak with regexp
> 
> On Thu, Sep 22, 2022 at 1:00 PM Sunil Kumar Kori <skori@marvell.com>
> wrote:
> > > @@ -210,15 +210,18 @@ rte_trace_regexp(const char *regex, bool
> enable)
> > >               return -EINVAL;
> > >
> > >       STAILQ_FOREACH(tp, &tp_list, next) {
> > > -             if (regexec(&r, tp->name, 0, NULL, 0) == 0) {
> > > -                     if (enable)
> > > -                             rc = rte_trace_point_enable(tp->handle);
> > > -                     else
> > > -                             rc = rte_trace_point_disable(tp->handle);
> > > -                     found = 1;
> > > +             if (regexec(&r, tp->name, 0, NULL, 0) != 0)
> > > +                     continue;
> > > +
> > > +             if (enable)
> > > +                     rc = rte_trace_point_enable(tp->handle);
> > > +             else
> > > +                     rc = rte_trace_point_disable(tp->handle);
> > > +             if (rc < 0) {
> > > +                     found = 0;
> > > +                     break;
> > >               }
> > > -             if (rc < 0)
> > > -                     return rc;
> > > +             found = 1;
> > >       }
> > >       regfree(&r);
> > >
> > > --
> >
> > I understand the problem addressed by this fix but may be following
> changes will be sufficient to fix it.
> > Please highlight, If I am missing. Just trying to reduce the line of changes.
> >
> > @@ -220,8 +220,10 @@ rte_trace_regexp(const char *regex, bool enable)
> >                                 rc = rte_trace_point_disable(tp->handle);
> >                         found = 1;
> >                 }
> > -               if (rc < 0)
> > -                       return rc;
> > +               if (rc < 0) {
> > +                       found = 0;
> > +                       break;
> > +               }
> >         }
> 
> 
> rc is compared against 0 for all non-matching tracepoints.
> This is unnecessary and fragile.
> 
> I can split this change in two: one for the fix, and one other where the loop is
> updated with a continue and an inverted matching condition like above.
> If going like this, I would update rte_trace_pattern() too, in the second patch.
> 
> WDYT?

Sounds okay. You can proceed in either way. No hard opinion on it. 
> 
> 
> --
> David Marchand