rtc: handle errors correctly in rtc_irq_set_state()
authorThomas Gleixner <tglx@linutronix.de>
Tue, 26 Jul 2011 23:08:18 +0000 (16:08 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 26 Jul 2011 23:49:41 +0000 (16:49 -0700)
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>
drivers/rtc/interface.c

index df68618f6dbb53f60f1f743f1425e2060e104854..b6bf57f25cc9e520ca31d642eea1616b9132f82b 100644 (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;