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>
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index df68618..b6bf57f 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -656,6 +656,8 @@
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 @@
hrtimer_cancel(&rtc->pie_timer);
}
rtc->pie_enabled = enabled;
+out:
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
return err;