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From: Markus Elfring <Markus.Elfring@web.de>
To: Wen Yang <wen.yang99@zte.com.cn>,
	linux-kernel@vger.kernel.org, cocci@systeme.lip6.fr
Cc: Yi Wang <wang.yi59@zte.com.cn>,
	Michal Marek <michal.lkml@markovi.net>,
	Nicolas Palix <nicolas.palix@imag.fr>
Subject: Re: [Cocci] [v2] coccinelle: semantic code search for missing of_node_put
Date: Sat, 29 Jun 2019 09:40:36 +0200	[thread overview]
Message-ID: <76641efc-2e3e-8664-03b2-4eb82f01c275@web.de> (raw)
In-Reply-To: <904b9362-cd01-ffc9-600b-0c48848617a0@web.de>

>> +if (x == NULL || ...) S
>> +... when != e = (T)x
>> +    when != true x == NULL
>
> I wonder if this code exclusion specification is really required
> after a null pointer was checked before.

I would like to add another view for this implementation detail.

The when constraint can express a software desire which can be reasonable
to some degree. You would like to be sure that a null pointer will not occur
after a corresponding check succeeded.

* But I feel unsure about the circumstances under which the Coccinelle software
  can determine this aspect actually.

* I find that it can eventually make sense only after the content of
  the local variable (which is identified by “x”) was modified.
  Thus I would find the exclusion of assignments more useful at this place.

Regards,
Markus
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  parent reply	other threads:[~2019-06-29  7:41 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-28  2:58 [Cocci] [PATCH v2] coccinelle: semantic code search for missing of_node_put Wen Yang
2019-06-28  9:38 ` Markus Elfring
2019-06-28 11:07   ` Julia Lawall
2019-06-28 14:16     ` [Cocci] [v2] " Markus Elfring
2019-06-28 14:16     ` Markus Elfring
2019-07-04  3:03     ` [Cocci] [PATCH v2] coccinelle: semantic code search for missingof_node_put wen.yang99
2019-07-04  6:28       ` [Cocci] [v2] coccinelle: semantic code search for missing of_node_put Markus Elfring
2019-07-05  5:29       ` [Cocci] [PATCH v2] coccinelle: semantic code search for missingof_node_put Julia Lawall
2019-07-05  5:57         ` [Cocci] [PATCH v2] coccinelle: semantic code search formissingof_node_put wen.yang99
2019-07-05  6:17           ` Julia Lawall
2019-07-05  6:45             ` [Cocci] [v2] coccinelle: semantic code search for missing of_node_put Markus Elfring
2019-06-29  7:40   ` Markus Elfring [this message]
2019-06-29  7:49     ` Julia Lawall
2019-06-29  8:35       ` Markus Elfring
2019-06-29 19:30       ` [Cocci] [v2] Coccinelle: Testing SmPL constraints Markus Elfring
2019-07-04  2:41   ` [Cocci] 答复: Re: [PATCH v2] coccinelle: semantic code search for missingof_node_put wen.yang99
2019-07-04  5:40     ` [Cocci] [v2] coccinelle: semantic code search for missing of_node_put Markus Elfring

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