From: Richard Cochran <richardcochran@gmail.com>
To: John Stultz <john.stultz@linaro.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Prarit Bhargava <prarit@redhat.com>,
Sharvil Nanavati <sharvil@google.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] alarmtimer: Fix bug where relative alarm timers were treated as absolute
Date: Tue, 8 Jul 2014 08:42:04 +0200 [thread overview]
Message-ID: <20140708064204.GD3977@localhost.localdomain> (raw)
In-Reply-To: <1404767171-6902-1-git-send-email-john.stultz@linaro.org>
On Mon, Jul 07, 2014 at 02:06:11PM -0700, John Stultz wrote:
> @@ -597,8 +602,16 @@ static int alarm_timer_set(struct k_itimer *timr, int flags,
>
> /* start the timer */
> timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
> - alarm_start(&timr->it.alarm.alarmtimer,
> - timespec_to_ktime(new_setting->it_value));
> + exp = timespec_to_ktime(new_setting->it_value);
> + /* Convert (if necessary) to absolute time */
> + if (flags != TIMER_ABSTIME) {
> + ktime_t now;
> +
> + now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
> + exp = ktime_add(now, exp);
> + }
> +
> + alarm_start(&timr->it.alarm.alarmtimer, exp);
Nothing protects 'exp' from becoming invalid before queuing the alarm,
if the time base is reset on another cpu. Or would that be harmless
here?
> return 0;
> }
Thanks,
Richard
next prev parent reply other threads:[~2014-07-08 6:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-07 21:06 [PATCH] alarmtimer: Fix bug where relative alarm timers were treated as absolute John Stultz
2014-07-08 6:42 ` Richard Cochran [this message]
2014-07-08 7:34 ` John Stultz
2014-07-08 8:52 ` [tip:timers/urgent] " tip-bot for John Stultz
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