diff options
| author | Baolin Wang <baolin.wang@linaro.org> | 2017-12-25 19:10:37 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-27 14:13:04 +0900 |
| commit | 018ea3fea1c6a60778bb95004aa34e4f155d52ab (patch) | |
| tree | 0507d1222b232883fd1e601f73979706d55bfe1f | |
| parent | 321c5ade5a06cb561459b5190ed5bd36a270ea5e (diff) | |
rtc: Fix overflow when converting time64_t to rtc_time
commit 36d46cdb43efea74043e29e2a62b13e9aca31452 upstream.
If we convert one large time values to rtc_time, in the original formula
'days * 86400' can be overflowed in 'unsigned int' type to make the formula
get one incorrect remain seconds value. Thus we can use div_s64_rem()
function to avoid this situation.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/rtc/rtc-lib.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c index e6bfb9c42a10..5b136bdc03d4 100644 --- a/drivers/rtc/rtc-lib.c +++ b/drivers/rtc/rtc-lib.c @@ -52,13 +52,11 @@ EXPORT_SYMBOL(rtc_year_days); */ void rtc_time64_to_tm(time64_t time, struct rtc_time *tm) { - unsigned int month, year; - unsigned long secs; + unsigned int month, year, secs; int days; /* time must be positive */ - days = div_s64(time, 86400); - secs = time - (unsigned int) days * 86400; + days = div_s64_rem(time, 86400, &secs); /* day of the week, 1970-01-01 was a Thursday */ tm->tm_wday = (days + 4) % 7; |