Hello Alessandro and Alexandre,
I noticed an interesting cmos_rtc.rtc.aie_timer on a Stratus machine
running the 4.6 kernel, with an expiration time that puts the alarm way
out into next year. This is easily reproducible on this machine by
setting a wakealarm sometime in the near future, then rebooting.
>From a fresh boot:
% cat /proc/driver/rtc
rtc_time : 17:55:10
rtc_date : 2016-06-09
alrm_time : 14:04:37
alrm_date : 2017-06-09 << 2017 ?
alarm_IRQ : no
alrm_pending : no
update IRQ enabled : no
periodic IRQ enabled : no
periodic IRQ frequency : 1024
max user IRQ frequency : 64
24hr : yes
periodic_IRQ : no
update_IRQ : no
HPET_emulated : yes
BCD : yes
DST_enable : no
periodic_freq : 1024
batt_status : okay
I added some debugging code to the kernel, saw this on the next boot:
__rtc_read_alarm: A - alarm->time.tm_year = -1, missing = 0
__rtc_read_alarm: B - alarm->time.tm_year = 116, missing = 3
__rtc_read_alarm: C - alarm->time.tm_year = 117
Corresponding to these parts of __rtc_read_alarm:
int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
...
enum { none, day, month, year } missing = none;
...
err = rtc_read_alarm_internal(rtc, alarm);
...
/* Fill in the missing alarm fields using the timestamp; we
* know there's at least one since alarm->time is invalid.
*/
...
[A]
if (alarm->time.tm_year == -1) {
alarm->time.tm_year = now.tm_year;
if (missing == none)
missing = year;
}
[B]
...
switch (missing) {
...
/* Year rollover ... easy except for leap years! */
case year:
dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
do {
alarm->time.tm_year++;
} while (!is_leap_year(alarm->time.tm_year + 1900)
&& rtc_valid_tm(&alarm->time) != 0);
[C] break;
I noticed that the missing year and month cases increment their
respective time units inside a do ... while (condition) loop, pushing
the default 'filled-in' values to now + 1.
Should this 'roll-over' code check for a valid date before incrementing
the alarm time? (See attached patch.) I think this might also apply to
a missing month field as well.
(After the patch + reboot):
% cat /proc/driver/rtc
rtc_time : 18:24:02
rtc_date : 2016-06-09
alrm_time : 14:04:37
alrm_date : 2016-06-09
alarm_IRQ : no
alrm_pending : no
update IRQ enabled : no
periodic IRQ enabled : no
periodic IRQ frequency : 1024
max user IRQ frequency : 64
24hr : yes
periodic_IRQ : no
update_IRQ : no
HPET_emulated : yes
BCD : yes
DST_enable : no
periodic_freq : 1024
batt_status : okay
-- >8 --
>From d6feacf20b312c8ebfee902b8b84f68c1a82f035 Mon Sep 17 00:00:00 2001
From: Joe Lawrence <[email protected]>
Date: Thu, 9 Jun 2016 14:52:28 -0400
Subject: [PATCH] rtc: check filled-in alarm values before incrementing
In __rtc_read_alarm, check filled-in alarm->time.tm_year values (those
not returned by the RTC and defaulted to now.tm_year) before
incrementing them in the rollover handling case.
Signed-off-by: Joe Lawrence <[email protected]>
---
drivers/rtc/interface.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 9ef5f6f89f98..3098ce4167ef 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -258,10 +258,10 @@ int __rtc_read_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alarm)
/* Year rollover ... easy except for leap years! */
case year:
dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
- do {
+ while (!is_leap_year(alarm->time.tm_year + 1900)
+ && rtc_valid_tm(&alarm->time) != 0) {
alarm->time.tm_year++;
- } while (!is_leap_year(alarm->time.tm_year + 1900)
- && rtc_valid_tm(&alarm->time) != 0);
+ }
break;
default:
--
1.8.3.1
