Patch "timers: Fix overflow in get_next_timer_interrupt" has been added to the 4.12-stable tree

Patch "timers: Fix overflow in get_next_timer_interrupt" has been added to the 4.12-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    timers: Fix overflow in get_next_timer_interrupt

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     timers-fix-overflow-in-get_next_timer_interrupt.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 34f41c0316ed52b0b44542491d89278efdaa70e4 Mon Sep 17 00:00:00 2001
From: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Date: Tue, 1 Aug 2017 09:11:52 +0200
Subject: timers: Fix overflow in get_next_timer_interrupt

From: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>

commit 34f41c0316ed52b0b44542491d89278efdaa70e4 upstream.

For e.g. HZ=100, timer being 430 jiffies in the future, and 32 bit
unsigned int, there is an overflow on unsigned int right-hand side
of the expression which results with wrong values being returned.

Type cast the multiplier to 64bit to avoid that issue.

Fixes: 46c8f0b077a8 ("timers: Fix get_next_timer_interrupt() computation")
Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Cc: khilman@baylibre.com
Cc: akpm@linux-foundation.org
Link: http://lkml.kernel.org/r/a7900f04-2a21-c9fd-67be-ab334d459ee5@nokia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/time/timer.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1495,7 +1495,7 @@ u64 get_next_timer_interrupt(unsigned lo
 		base->is_idle = false;
 	} else {
 		if (!is_max_delta)
-			expires = basem + (nextevt - basej) * TICK_NSEC;
+			expires = basem + (u64)(nextevt - basej) * TICK_NSEC;
 		/*
 		 * If we expect to sleep more than a tick, mark the base idle:
 		 */


Patches currently in stable-queue which might be from matija.glavinic-pecotic.ext@nokia.com are

queue-4.12/timers-fix-overflow-in-get_next_timer_interrupt.patch