From: Nick Crews <ncrews@chromium.org>
To: Alexandre Belloni <alexandre.belloni@bootlin.com>,
Alessandro Zummo <a.zummo@towertech.it>
Cc: linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org,
Pavel Machek <pavel@ucw.cz>,
enric.balletbo@collabora.com, bleung@chromium.org,
dlaurie@chromium.org, djkurtz@chromium.org, dtor@google.com,
Nick Crews <ncrews@chromium.org>
Subject: [PATCH v3] rtc: wilco-ec: Handle reading invalid times
Date: Wed, 25 Sep 2019 14:32:09 -0600 [thread overview]
Message-ID: <20190925203209.79941-1-ncrews@chromium.org> (raw)
If the RTC HW returns an invalid time, the rtc_year_days()
call would crash. This patch adds error logging in this
situation, and removes the tm_yday and tm_wday calculations.
These fields should not be relied upon by userspace
according to man rtc, and thus we don't need to calculate
them.
Signed-off-by: Nick Crews <ncrews@chromium.org>
---
drivers/rtc/rtc-wilco-ec.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/rtc/rtc-wilco-ec.c b/drivers/rtc/rtc-wilco-ec.c
index 8ad4c4e6d557..53da355d996a 100644
--- a/drivers/rtc/rtc-wilco-ec.c
+++ b/drivers/rtc/rtc-wilco-ec.c
@@ -110,10 +110,15 @@ static int wilco_ec_rtc_read(struct device *dev, struct rtc_time *tm)
tm->tm_mday = rtc.day;
tm->tm_mon = rtc.month - 1;
tm->tm_year = rtc.year + (rtc.century * 100) - 1900;
- tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
-
- /* Don't compute day of week, we don't need it. */
- tm->tm_wday = -1;
+ /* Ignore other tm fields, man rtc says userspace shouldn't use them. */
+
+ if (rtc_valid_tm(tm)) {
+ dev_err(dev,
+ "Time from RTC is invalid: second=%u, minute=%u, hour=%u, day=%u, month=%u, year=%u, century=%u",
+ rtc.second, rtc.minute, rtc.hour, rtc.day, rtc.month,
+ rtc.year, rtc.century);
+ return -EIO;
+ }
return 0;
}
--
2.21.0
next reply other threads:[~2019-09-25 20:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 20:32 Nick Crews [this message]
2019-09-25 20:51 ` [PATCH v3] rtc: wilco-ec: Handle reading invalid times Dmitry Torokhov
2019-10-01 19:53 ` Alexandre Belloni
2019-10-01 20:42 ` Dmitry Torokhov
2019-10-02 10:32 ` Alexandre Belloni
2019-10-02 15:20 ` Dmitry Torokhov
2019-10-02 15:34 ` Alexandre Belloni
2019-10-03 20:37 ` Nick Crews
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