From: Julia Lawall <julia.lawall@lip6.fr>
To: Markus Elfring <Markus.Elfring@web.de>
Cc: kernel-janitors@vger.kernel.org,
Michal Marek <michal.lkml@markovi.net>,
Wen Yang <yellowriver2010@hotmail.com>,
Nicolas Palix <nicolas.palix@imag.fr>,
LKML <linux-kernel@vger.kernel.org>,
Coccinelle <cocci@systeme.lip6.fr>,
Cheng Shengyu <cheng.shengyu@zte.com.cn>,
Wen Yang <wen.yang99@zte.com.cn>
Subject: Re: [Cocci] [PATCH v6] coccinelle: semantic code search for missing put_device()
Date: Sun, 17 Feb 2019 12:37:18 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1902171235570.2444@hadrien> (raw)
In-Reply-To: <8e7ba7c0-b7fe-a1f0-d28b-0c716ecbcfdb@web.de>
On Sun, 17 Feb 2019, Markus Elfring wrote:
> > +@search exists@
> > +local idexpression id;
> > +expression x,e,e1;
> > +position p1,p2;
> > +type T,T1,T2;
> > +@@
> > +
> > +id = of_find_device_by_node@p1(x)
> > +... when != e = id
>
> I suggest to increase your software development attention also for
> another implementation detail.
> Source code analysis triggers challenges for safe data flow handling.
> the semantic patch language supports search specifications for
> the exclusion of specific assignments.
>
> Does this SmPL code contain a questionable order for the source
> and target metavariables?
> Can the following variant be more appropriate?
>
> + ... when != id = e
This is possible, but I think unlikely.
>
>
> > +if (id == NULL || ...) { ... return ...; }
> > +... when != put_device(&id->dev)
> > + when != platform_device_put(id)
> > + when != of_dev_put(id)
> > + when != if (id) { ... put_device(&id->dev) ... }
> > + when != e1 = (T)id
>
> Would you like to avoid that the return value from the shown function call
> gets overwritten in the variable before it was used once at least
> (when a bit of extra C code is tolerated before a null pointer check)?
Indeed there should be a put then too, but again, it seems unlikely.
julia
>
> Regards,
> Markus
>
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next prev parent reply other threads:[~2019-02-17 11:37 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-16 16:05 [Cocci] [PATCH v6] coccinelle: semantic code search for missing put_device() Wen Yang
2019-02-16 16:33 ` Julia Lawall
2019-02-16 18:39 ` [Cocci] [v6] " Markus Elfring
2019-02-17 2:32 ` [Cocci] 答复: " Wen Yang
2019-02-17 7:42 ` Markus Elfring
2019-02-17 9:50 ` [Cocci] [PATCH v6] " Markus Elfring
2019-02-17 11:37 ` Julia Lawall [this message]
2019-02-17 11:42 ` Markus Elfring
2019-02-17 11:48 ` Julia Lawall
2019-02-17 12:00 ` [Cocci] [v6] " Markus Elfring
2019-02-17 12:05 ` Julia Lawall
2019-02-17 12:20 ` Markus Elfring
2019-02-17 12:52 ` Julia Lawall
2019-02-17 13:14 ` Markus Elfring
2019-02-18 3:22 ` wen.yang99
2019-02-18 6:43 ` Julia Lawall
2019-02-18 8:19 ` Markus Elfring
2019-02-19 2:14 ` wen.yang99
2019-02-19 7:04 ` Julia Lawall
2019-02-19 8:12 ` Markus Elfring
2019-02-19 8:29 ` Markus Elfring
2019-02-19 9:09 ` wen.yang99
2019-02-19 9:30 ` Markus Elfring
2019-03-06 11:18 ` Markus Elfring
2019-02-18 21:40 ` Markus Elfring
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