cocci.inria.fr archive mirror
 help / color / mirror / Atom feed
From: Markus Elfring <Markus.Elfring@web.de>
To: Wen Yang <yellowriver2010@hotmail.com>,
	Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Michal Marek <michal.lkml@markovi.net>,
	kernel-janitors@vger.kernel.org,
	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 10:50:05 +0100	[thread overview]
Message-ID: <8e7ba7c0-b7fe-a1f0-d28b-0c716ecbcfdb@web.de> (raw)
In-Reply-To: <HK0PR02MB36344E2B29CEB195892F6420B2610@HK0PR02MB3634.apcprd02.prod.outlook.com>

> +@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


> +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)?

Regards,
Markus
_______________________________________________
Cocci mailing list
Cocci@systeme.lip6.fr
https://systeme.lip6.fr/mailman/listinfo/cocci

  parent reply	other threads:[~2019-02-17  9:51 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 ` Markus Elfring [this message]
2019-02-17 11:37   ` [Cocci] [PATCH v6] " Julia Lawall
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=8e7ba7c0-b7fe-a1f0-d28b-0c716ecbcfdb@web.de \
    --to=markus.elfring@web.de \
    --cc=Julia.Lawall@lip6.fr \
    --cc=cheng.shengyu@zte.com.cn \
    --cc=cocci@systeme.lip6.fr \
    --cc=kernel-janitors@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=michal.lkml@markovi.net \
    --cc=nicolas.palix@imag.fr \
    --cc=wen.yang99@zte.com.cn \
    --cc=yellowriver2010@hotmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).