linux-kernel - Re: [PATCH] Coccinelle: doubletest: reduce side effect false positives

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Date:   Mon, 13 Aug 2018 16:29:42 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Julia Lawall <Julia.Lawall@...6.fr>
Cc:     kernel-janitors@...r.kernel.org,
        Gilles Muller <Gilles.Muller@...6.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Michal Marek <michal.lkml@...kovi.net>, cocci@...teme.lip6.fr,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Finn Thain <fthain@...egraphics.com.au>,
        zhong jiang <zhongjiang@...wei.com>,
        Michael Schmitz <schmitzmic@...il.com>,
        "James E . J . Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        John Garry <john.garry@...wei.com>,
        linux-scsi <linux-scsi@...r.kernel.org>
Subject: Re: [PATCH] Coccinelle: doubletest: reduce side effect false positives

2018-08-04 1:32 GMT+09:00 Julia Lawall <Julia.Lawall@...6.fr>:
> Ensure that the cited expression is not a function call or an
> assignment to reduce the chance of false positives.
>
> Slightly modify the warning message to indicate another source
> of false positves.
>
> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
>


Applied to linux-kbuild. Thanks!


(Please send a reminder
if there are more coccinelle patches I missed.)




> ---
>  scripts/coccinelle/tests/doubletest.cocci |   34 ++++++++++++++++++++++--------
>  1 file changed, 26 insertions(+), 8 deletions(-)
>
> diff --git a/scripts/coccinelle/tests/doubletest.cocci b/scripts/coccinelle/tests/doubletest.cocci
> index 78d74c2..7af2ce7 100644
> --- a/scripts/coccinelle/tests/doubletest.cocci
> +++ b/scripts/coccinelle/tests/doubletest.cocci
> @@ -1,6 +1,7 @@
>  /// Find &&/|| operations that include the same argument more than once
> -//# A common source of false positives is when the argument performs a side
> -//# effect.
> +//# A common source of false positives is when the expression, or
> +//# another expresssion in the same && or || operation, performs a
> +//# side effect.
>  ///
>  // Confidence: Moderate
>  // Copyright: (C) 2010 Nicolas Palix, DIKU.  GPLv2.
> @@ -20,20 +21,37 @@ position p;
>  @@
>
>  (
> -* E@p
> -  || ... || E
> + E@p || ... || E
>  |
> -* E@p
> -  && ... && E
> + E@p && ... && E
>  )
>
> -@...ipt:python depends on org@
> +@bad@
> +expression r.E,e1,e2,fn;
> +position r.p;
> +assignment operator op;
> +@@
> +
> +(
> +E@p
> +&
> + <+... \(fn(...)\|e1 op e2\|e1++\|e1--\|++e1\|--e1\) ...+>
> +)
> +
> +@...ends on context && !bad@
> +expression r.E;
> +position r.p;
> +@@
> +
> +*E@p
> +
> +@...ipt:python depends on org && !bad@
>  p << r.p;
>  @@
>
>  cocci.print_main("duplicated argument to && or ||",p)
>
> -@...ipt:python depends on report@
> +@...ipt:python depends on report && !bad@
>  p << r.p;
>  @@
>
>



-- 
Best Regards
Masahiro Yamada