Patchwork RTC: Fix infinite loop in initializing the alarm.

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Submitter Ales Novak
Date April 7, 2014, 10:54 p.m.
Message ID <1396911282-4410-1-git-send-email-alnovak@suse.cz>
Download mbox | patch
Permalink /patch/337550/
State New
Headers show

Comments

Ales Novak - April 7, 2014, 10:54 p.m.
In __rtc_read_alarm(), if the alarm time retrieved by
rtc_read_alarm_internal() from the device contains invalid values
(e.g. month=2,mday=31) and the year not set (=-1), the initialization
will loop infinitely because the year-fixing loop expects the
time being invalid due to leap year.

Fix reduces the loop to the leap years and adds final validity check.

Signed-off-by: Ales Novak <alnovak@suse.cz>
---
 drivers/rtc/interface.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)
Alessandro Zummo - April 8, 2014, 2:43 p.m.
On Tue,  8 Apr 2014 00:54:42 +0200
Ales Novak <alnovak@suse.cz> wrote:

> In __rtc_read_alarm(), if the alarm time retrieved by
> rtc_read_alarm_internal() from the device contains invalid values
> (e.g. month=2,mday=31) and the year not set (=-1), the initialization
> will loop infinitely because the year-fixing loop expects the
> time being invalid due to leap year.
> 
> Fix reduces the loop to the leap years and adds final validity check.
> 
> Signed-off-by: Ales Novak <alnovak@suse.cz>

 Seems reasonable.

 Acked-by: Alessandro Zummo <a.zummo@towertech.it>

Patch

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 544be72..a2df283 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -292,7 +292,9 @@  int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
 		do {
 			alarm->time.tm_year++;
-		} while (rtc_valid_tm(&alarm->time) != 0);
+		} while (alarm->time.tm_mon == 1
+			&& is_leap_year(alarm->time.tm_year + 1900)
+			&& rtc_valid_tm(&alarm->time) != 0);
 		break;
 
 	default:
@@ -300,7 +302,16 @@  int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 	}
 
 done:
-	return 0;
+	err = rtc_valid_tm(&alarm->time);
+
+	if (err) {
+		dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
+			alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
+			alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
+			alarm->time.tm_sec);
+	}
+
+	return err;
 }
 
 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)