Commit 9aa0d0be authored Oct 04, 2019 by Nick Crews Committed by Alexandre Belloni Oct 14, 2019

rtc: wilco-ec: Handle reading invalid times



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>
Reviewed-by: Daniel Campello <campello@chromium.org>
Link: https://lore.kernel.org/r/20191004142608.170159-1-ncrews@chromium.org


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

parent 147dae76

drivers/rtc/rtc-wilco-ec.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -110,10 +110,12 @@ 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);
		/* Ignore other tm fields, man rtc says userspace shouldn't use them. */

		/* Don't compute day of week, we don't need it. */
		tm->tm_wday = -1;
		if (rtc_valid_tm(tm)) {
		dev_err(dev, "Time from RTC is invalid: %ptRr\n", tm);
		return -EIO;
		}

		return 0;
		}

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