Commit cc4b6e77 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Greg Kroah-Hartman

rtc: handle errors correctly in rtc_irq_set_state()

commit 2c4f57d1 upstream.

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: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ben Greear <greearb@candelatech.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 0f231ea4
......@@ -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;
......
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