From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@linaro.org (Kevin Hilman) Date: Mon, 16 Sep 2013 15:43:49 -0700 Subject: [PATCH 2/2] sched/nohz: fix overflow error in scheduler_tick_max_deferment() In-Reply-To: <1379371429-22214-1-git-send-email-khilman@linaro.org> References: <1379371429-22214-1-git-send-email-khilman@linaro.org> Message-ID: <1379371429-22214-2-git-send-email-khilman@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The conversion of the max deferment from usecs to nsecs can easily overflow on platforms where a long is 32-bits. To fix, cast the usecs value to u64 before multiplying by NSECS_PER_USEC. This was discovered on 32-bit ARM platform when extending the max deferment value. Cc: Frederic Weisbecker Signed-off-by: Kevin Hilman --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4b1fe3e..3d7c80e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2203,7 +2203,7 @@ u64 scheduler_tick_max_deferment(void) if (time_before_eq(next, now)) return 0; - return jiffies_to_usecs(next - now) * NSEC_PER_USEC; + return (u64)jiffies_to_usecs(next - now) * NSEC_PER_USEC; } static __init int sched_nohz_full_init_debug(void) -- 1.8.3