Commit f423fc62 authored Jan 04, 2012 by Linus Torvalds

Revert "rtc: Expire alarms after the time is set."



This reverts commit 93b2ec01.

The call to "schedule_work()" in rtc_initialize_alarm() happens too
early, and can cause oopses at bootup

Neil Brown explains why we do it:

  "If you set an alarm in the future, then shutdown and boot again after
   that time, then you will end up with a timer_queue node which is in
   the past.

   When this happens the queue gets stuck.  That entry-in-the-past won't
   get removed until and interrupt happens and an interrupt won't happen
   because the RTC only triggers an interrupt when the alarm is "now".

   So you'll find that e.g.  "hwclock" will always tell you that
   'select' timed out.

   So we force the interrupt work to happen at the start just in case."

and has a patch that convert it to do things in-process rather than with
the worker thread, but right now it's too late to play around with this,
so we just revert the patch that caused problems for now.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Requested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Requested-by: John Stultz <john.stultz@linaro.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 157e8bf8

drivers/rtc/interface.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -73,8 +73,6 @@ int rtc_set_time(struct rtc_device rtc, struct rtc_time tm)
		err = -EINVAL;

		mutex_unlock(&rtc->ops_lock);
		/* A timer might have just expired */
		schedule_work(&rtc->irqwork);
		return err;
		}
		EXPORT_SYMBOL_GPL(rtc_set_time);
		@@ -114,8 +112,6 @@ int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
		err = -EINVAL;

		mutex_unlock(&rtc->ops_lock);
		/* A timer might have just expired */
		schedule_work(&rtc->irqwork);

		return err;
		}
		@@ -400,8 +396,6 @@ int rtc_initialize_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
		timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
		}
		mutex_unlock(&rtc->ops_lock);
		/* maybe that was in the past.*/
		schedule_work(&rtc->irqwork);
		return err;
		}
		EXPORT_SYMBOL_GPL(rtc_initialize_alarm);

Admin message