From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753264Ab3LQVXO (ORCPT ); Tue, 17 Dec 2013 16:23:14 -0500 Received: from mail-pa0-f42.google.com ([209.85.220.42]:41998 "EHLO mail-pa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752962Ab3LQVXM (ORCPT ); Tue, 17 Dec 2013 16:23:12 -0500 From: Kevin Hilman To: Frederic Weisbecker , Thomas Gleixner Cc: linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org Subject: [PATCH 2/2] sched/nohz: fix overflow error in scheduler_tick_max_deferment() Date: Tue, 17 Dec 2013 13:23:08 -0800 Message-Id: <1387315388-31676-2-git-send-email-khilman@linaro.org> X-Mailer: git-send-email 1.8.3 In-Reply-To: <1387315388-31676-1-git-send-email-khilman@linaro.org> References: <1387315388-31676-1-git-send-email-khilman@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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 4b1fe3e69fe4..3d7c80e1c4d9 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