Commit 6a929b97 authored Jun 05, 2018 by Alexandre Belloni Committed by Greg Kroah-Hartman Aug 03, 2018

rtc: ensure rtc_set_alarm fails when alarms are not supported



[ Upstream commit abfdff44bc38e9e2ef7929f633fb8462632299d4 ]

When using RTC_ALM_SET or RTC_WKALM_SET with rtc_wkalrm.enabled not set,
rtc_timer_enqueue() is not called and rtc_set_alarm() may succeed but the
subsequent RTC_AIE_ON ioctl will fail. RTC_ALM_READ would also fail in that
case.

Ensure rtc_set_alarm() fails when alarms are not supported to avoid letting
programs think the alarms are working for a particular RTC when they are
not.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 191d00f8

drivers/rtc/interface.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -359,6 +359,11 @@ int rtc_set_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
		{
		int err;

		if (!rtc->ops)
		return -ENODEV;
		else if (!rtc->ops->set_alarm)
		return -EINVAL;

		err = rtc_valid_tm(&alarm->time);
		if (err != 0)
		return err;