Commit a078c6d0 authored Mar 15, 2012 by Sasha Levin Committed by Thomas Gleixner Mar 15, 2012

ntp: Fix integer overflow when setting time



'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


Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent f910381a

kernel/time/ntp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -289,7 +289,7 @@ static inline s64 ntp_update_offset_fll(s64 offset64, long secs)

		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)