4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Baolin Wang <baolin.wang@xxxxxxxxxx>
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@xxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/rtc/rtc-lib.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- 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;
