rtc: handle errors correctly in rtc_irq_set_state()

The code checks the correctness of the parameters, but unconditionally
arms/disarms the hrtimer.

The result is that a random task might arm/disarm rtc timer and surprise
the real owner by either generating events or by stopping them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ben Greear <greearb@candelatech.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Thomas Gleixner 2011-07-26 16:08:18 -07:00 committed by Linus Torvalds
parent b45d59fb92
commit 2c4f57d12d

View File

@ -656,6 +656,8 @@ int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled
err = -EBUSY;
if (rtc->irq_task != task)
err = -EACCES;
if (err)
goto out;
if (enabled) {
ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
@ -664,6 +666,7 @@ int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled
hrtimer_cancel(&rtc->pie_timer);
}
rtc->pie_enabled = enabled;
out:
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
return err;