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authorBaolin Wang <baolin.wang@linaro.org>2017-12-25 14:10:37 +0300
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2018-02-13 23:30:28 +0300
commit36d46cdb43efea74043e29e2a62b13e9aca31452 (patch)
treeb7b9dcfd8cb8805f3d2163cccbd2a96ec70c5d05
parent29a1f599c0cc37004f92ba455d1ccda3db0b6a94 (diff)
downloadlinux-36d46cdb43efea74043e29e2a62b13e9aca31452.tar.xz
rtc: Fix overflow when converting time64_t to rtc_time
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>
-rw-r--r--drivers/rtc/rtc-lib.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
index 1ae7da5cfc60..ad5bb21908e5 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;