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Date: Fri, 14 May 2010 18:03:57 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Andrey Vagin <avagin@openvz.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       stable@kernel.org, Pavel Emelyanov <xemul@openvz.org>,
       Stanislaw Gruszka <sgruszka@redhat.com>
Subject: Re: [PATCH 2/2] posix_timer: clean up properly if anything fails
	after *_timer_create
Message-ID: <20100514160357.GB3727@redhat.com>
References: <1273843731-12595-1-git-send-email-avagin@openvz.org> <1273843731-12595-2-git-send-email-avagin@openvz.org>
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On 05/14, Andrey Vagin wrote:
>
> *_timer_create may allocate/get some resources, so need call *_timer_cleanup.
>
> https://bugzilla.sw.ru/show_bug.cgi?id=473702

Authorization Required

> --- a/kernel/posix-timers.c
> +++ b/kernel/posix-timers.c
> @@ -574,19 +574,19 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
>  	if (copy_to_user(created_timer_id,
>  			 &new_timer_id, sizeof (new_timer_id))) {
>  		error = -EFAULT;
> -		goto out;
> +		goto out_cleanup;
>  	}
>  	if (timer_event_spec) {
>  		if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
>  			error = -EFAULT;
> -			goto out;
> +			goto out_cleanup;
>  		}
>  		rcu_read_lock();
>  		new_timer->it_pid = get_pid(good_sigevent(&event));
>  		rcu_read_unlock();
>  		if (!new_timer->it_pid) {
>  			error = -EINVAL;
> -			goto out;
> +			goto out_cleanup;
>  		}
>  	} else {
>  		event.sigev_notify = SIGEV_SIGNAL;
> @@ -613,6 +613,8 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
>  	 * and may cease to exist at any time.  Don't use or modify
>  	 * new_timer after the unlock call.
>  	 */
> +out_cleanup:
> +	CLOCK_DISPATCH(new_timer->it_clock, timer_cleanup, (new_timer));

But at first glance you are right, posix_cpu_timer_create() does
get_task_struct(it.cpu.task).

Oleg.