linux-kernel - Re: [Cocci] [PATCH 1/1] kprobes: Deletion of an unnecessary check before the function call "module_put"

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Message-ID: <alpine.DEB.2.10.1411161428190.2364@hadrien>
Date:	Sun, 16 Nov 2014 14:29:02 +0100 (CET)
From:	Julia Lawall <julia.lawall@...6.fr>
To:	SF Markus Elfring <elfring@...rs.sourceforge.net>
cc:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
	"David S. Miller" <davem@...emloft.net>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
	Coccinelle <cocci@...teme.lip6.fr>
Subject: Re: [Cocci] [PATCH 1/1] kprobes: Deletion of an unnecessary check
 before the function call "module_put"

On Sun, 16 Nov 2014, SF Markus Elfring wrote:

> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Sun, 16 Nov 2014 12:20:31 +0100
>
> The module_put() function tests whether its argument is NULL and then
> returns immediately. Thus the test around the call is not needed.
>
> This issue was detected by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  kernel/kprobes.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 3995f54..f1e7d45 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1527,8 +1527,7 @@ int register_kprobe(struct kprobe *p)
>  out:
>  	mutex_unlock(&kprobe_mutex);
>
> -	if (probed_mod)
> -		module_put(probed_mod);
> +	module_put(probed_mod);

There is an out label, so please check whether the labels could not be
better positioned to avoid calling module_put when it is not needed.

julia

>
>  	return ret;
>  }
> --
> 2.1.3
>
>
> _______________________________________________
> Cocci mailing list
> Cocci@...teme.lip6.fr
> https://systeme.lip6.fr/mailman/listinfo/cocci
>
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