Commit a0211af5 authored by Yu Liao's avatar Yu Liao Committed by Xiongfeng Wang
Browse files

rtc: Fix race when disable/enable UIE in rtc_set_time() 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBV6W4



--------------------------------

When the RTC_SET_TIME and RTC_RD_TIME threads run in parallel,
there is no guarantee that uie_rtctimer.enabled is equal to the
previously read uie when executing rtc->ops->set_time.

Fix this by keeping reading uie state, disabling uie, setting
rtc time and enabling uie in critical sections.

Fixes: 7e7c005b ("rtc: disable uie before setting time and enable after")
Signed-off-by: default avatarYu Liao <liaoyu15@huawei.com>
Signed-off-by: default avatarXiongfeng Wang <wangxiongfeng2@huawei.com>
parent e28c0bf7

drivers/rtc/interface.c

+12 −16
Original line number Diff line number Diff line
@@ -139,20 +139,18 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) 


	rtc_subtract_offset(rtc, tm);



#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active;

#else

	uie = rtc->uie_rtctimer.enabled;

#endif

	if (uie) {

		err = rtc_update_irq_enable(rtc, 0);

	err = mutex_lock_interruptible(&rtc->ops_lock);

	if (err)

		return err;

	}



	err = mutex_lock_interruptible(&rtc->ops_lock);

	if (err)

	uie = rtc->uie_rtctimer.enabled;

	if (uie) {

		err = __rtc_update_irq_enable(rtc, 0);

		if (err) {

			mutex_unlock(&rtc->ops_lock);

			return err;

		}

	}



	if (!rtc->ops)

		err = -ENODEV;
@@ -169,16 +167,14 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) 
		err = -EINVAL;



	pm_stay_awake(rtc->dev.parent);



	if (uie)

		err = __rtc_update_irq_enable(rtc, 1);



	mutex_unlock(&rtc->ops_lock);

	/* A timer might have just expired */

	schedule_work(&rtc->irqwork);



	if (uie) {

		err = rtc_update_irq_enable(rtc, 1);

		if (err)

			return err;

	}



	trace_rtc_set_time(rtc_tm_to_time64(tm), err);

	return err;

}