From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755231AbbLKMyu (ORCPT ); Fri, 11 Dec 2015 07:54:50 -0500 Received: from mx2.parallels.com ([199.115.105.18]:40460 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755141AbbLKMys (ORCPT ); Fri, 11 Dec 2015 07:54:48 -0500 From: Andrey Ryabinin To: , CC: , , Andrey Ryabinin Subject: [PATCH] sched/fair: fix mul overflow on 32-bit systems Date: Fri, 11 Dec 2015 15:55:18 +0300 Message-ID: <1449838518-26543-1-git-send-email-aryabinin@virtuozzo.com> X-Mailer: git-send-email 2.4.10 MIME-Version: 1.0 Content-Type: text/plain X-ClientProxiedBy: US-EXCH2.sw.swsoft.com (10.255.249.46) To US-EXCH.sw.swsoft.com (10.255.249.47) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make 'r' 64-bit type to avoid overflow in 'r * LOAD_AVG_MAX' on 32-bit systems: UBSAN: Undefined behaviour in kernel/sched/fair.c:2785:18 signed integer overflow: 87950 * 47742 cannot be represented in type 'int' Fixes: 9d89c257dfb9 ("sched/fair: Rewrite runnable load and utilization average tracking") Signed-off-by: Andrey Ryabinin --- kernel/sched/fair.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e3266eb..733f0b8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2780,14 +2780,14 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) int decayed, removed = 0; if (atomic_long_read(&cfs_rq->removed_load_avg)) { - long r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); + s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); sa->load_avg = max_t(long, sa->load_avg - r, 0); sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0); removed = 1; } if (atomic_long_read(&cfs_rq->removed_util_avg)) { - long r = atomic_long_xchg(&cfs_rq->removed_util_avg, 0); + s64 r = atomic_long_xchg(&cfs_rq->removed_util_avg, 0); sa->util_avg = max_t(long, sa->util_avg - r, 0); sa->util_sum = max_t(s32, sa->util_sum - r * LOAD_AVG_MAX, 0); } -- 2.4.10