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Date: Thu, 2 Feb 2012 07:53:38 -0800
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Josh Triplett <josh@freedesktop.org>, kernel-janitors@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3 v2] kernel/rcutorture.c: Move call to PTR_ERR after
 reassignment
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References: <1328194382-32465-1-git-send-email-Julia.Lawall@lip6.fr>
 <1328194382-32465-4-git-send-email-Julia.Lawall@lip6.fr>
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Queued, thank you both!

							Thanx, Paul

On Thu, Feb 02, 2012 at 03:53:02PM +0100, Julia Lawall wrote:
> From: Julia Lawall <Julia.Lawall@lip6.fr>
> 
> PTR_ERR should be called before its argument is cleared.
> 
> The semantic match that finds this problem is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@
> expression e,e1;
> constant c;
> @@
> 
> *e = c
> ... when != e = e1
>     when != &e
>     when != true IS_ERR(e)
> *PTR_ERR(e)
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> Reported-by: Josh Triplett <josh@joshtriplett.org>
> 
> ---
> v2: correct commit message.
> 
>  kernel/rcutorture.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
> index a58ac28..4b3cd87 100644
> --- a/kernel/rcutorture.c
> +++ b/kernel/rcutorture.c
> @@ -1450,12 +1450,15 @@ rcu_torture_onoff(void *arg)
>  static int __cpuinit
>  rcu_torture_onoff_init(void)
>  {
> +	int ret;
> +
>  	if (onoff_interval <= 0)
>  		return 0;
>  	onoff_task = kthread_run(rcu_torture_onoff, NULL, "rcu_torture_onoff");
>  	if (IS_ERR(onoff_task)) {
> +		ret = PTR_ERR(onoff_task);
>  		onoff_task = NULL;
> -		return PTR_ERR(onoff_task);
> +		return ret;
>  	}
>  	return 0;
>  }
>