Re: [PATCH v5] Coccinelle: semantic code search for missing put_device()

[Julia Lawall]

On Fri, 15 Feb 2019, Markus Elfring wrote:

> > +@search exists@
> > +local idexpression id;
> > +expression x,e,e1;
> > +position p1,p2;
> > +type T,T1,T2,T3;
> > +@@
> > +
> > +id = of_find_device_by_node@p1(x)
> > +... when != e = id
> > +if (id == NULL || ...) { ... return ...; }
> > +... when != put_device(&id->dev)
> â
> > +    when != if (id) { ... put_device(&id->dev) ... }
> â
>
> I would interpret this SmPL code in the way that the if statement
> for the pointer check is âoptionalâ in this line.
> Is it an extra and redundant SmPL specification when the reference
> release function could eventually be found just anywhere within
> an implementation?

The proposed when code is correct.  It is not redundant, because it checks
for a particular control-flow pattern.

julia

>
>
> Will a need evolve to develop a similar source code search approach
> for safer resource management with other function combinations?
>
> Regards,
> Markus
>