| From a078c6d0e6288fad6d83fb6d5edd91ddb7b6ab33 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <levinsasha928@gmail.com> |
| Date: Thu, 15 Mar 2012 12:36:14 -0400 |
| Subject: ntp: Fix integer overflow when setting time |
| |
| From: Sasha Levin <levinsasha928@gmail.com> |
| |
| commit a078c6d0e6288fad6d83fb6d5edd91ddb7b6ab33 upstream. |
| |
| 'long secs' is passed as divisor to div_s64, which accepts a 32bit |
| divisor. On 64bit machines that value is trimmed back from 8 bytes |
| back to 4, causing a divide by zero when the number is bigger than |
| (1 << 32) - 1 and all 32 lower bits are 0. |
| |
| Use div64_long() instead. |
| |
| Signed-off-by: Sasha Levin <levinsasha928@gmail.com> |
| Cc: johnstul@us.ibm.com |
| Link: http://lkml.kernel.org/r/1331829374-31543-2-git-send-email-levinsasha928@gmail.com |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/time/ntp.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/kernel/time/ntp.c |
| +++ b/kernel/time/ntp.c |
| @@ -275,7 +275,7 @@ static inline s64 ntp_update_offset_fll( |
| |
| time_status |= STA_MODE; |
| |
| - return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs); |
| + return div64_long(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs); |
| } |
| |
| static void ntp_update_offset(long offset) |
