linux-kernel - Re: [PATCH] coccinelle: api: add kzfree script

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Message-ID: <96653281-3812-8b44-0dd8-6e7540a26a89@web.de>
Date:   Thu, 4 Jun 2020 17:20:58 +0200
From:   Markus Elfring <Markus.Elfring@....de>
To:     Denis Efremov <efremov@...ux.com>,
        Gilles Muller <Gilles.Muller@...6.fr>,
        Julia Lawall <Julia.Lawall@...6.fr>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Coccinelle <cocci@...teme.lip6.fr>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] coccinelle: api: add kzfree script

> Check for memset() with 0 followed by kfree().

I suggest to simplify the SmPL code a bit like the following.


> +virtual context
> +virtual org
> +virtual report
> +virtual patch

+virtual context, org, report, patch


…
> +@@
> +
> +(
> +* memset(E, 0, ...);
> +|
> +* memset(E, '\0', ...);
> +)
> +* kfree(E)@p;

+@@
+*memset(E, 0, ...);
+*kfree(E)@p;


How does the SmPL asterisk functionality fit to the operation
modes “org” and “report”?


> +@@
> +
> +(
> +- memset(E, 0, ...);
> +|
> +- memset(E, '\0', ...);
> +)
> +- kfree(E);
> ++ kzfree(E);

+@@
+-memset(E, 0, ...);
+-kfree
++kzfree
+       (E);

I got the impression that the specification of a SmPL disjunction
could be omitted because of the technical detail that the isomorphism
“zero_multiple_format” should handle such an use case already.

Would you like to tolerate any extra source code between these function calls?

Regards,
Markus