linux-kernel - Re: [PATCH 2/2] posix_timer: clean up properly if anything fails after *_timer

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Message-ID: <20100514160357.GB3727@redhat.com>
Date:	Fri, 14 May 2010 18:03:57 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Andrey Vagin <avagin@...nvz.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, stable@...nel.org,
	Pavel Emelyanov <xemul@...nvz.org>,
	Stanislaw Gruszka <sgruszka@...hat.com>
Subject: Re: [PATCH 2/2] posix_timer: clean up properly if anything fails
	after *_timer_create

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.

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