Messages in this thread Patch in this message | | | From | Matija Glavinic Pecotic <> | Subject | [PATCH] timers: Fix overflow in get_next_timer_interrupt | Date | Tue, 1 Aug 2017 09:11:52 +0200 |
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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.
Problem was observed on tickless core and with following applied:
sched/nohz: add debugfs control over sched_tick_max_deferment https://lkml.org/lkml/2013/9/16/499
Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com> --- kernel/time/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 71ce3f4..8f5d1bf 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1495,7 +1495,7 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) 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: */ -- 2.1.4
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