From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752894Ab2HGGaP (ORCPT ); Tue, 7 Aug 2012 02:30:15 -0400 Received: from mailout-de.gmx.net ([213.165.64.22]:37258 "HELO mailout-de.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751523Ab2HGGaO (ORCPT ); Tue, 7 Aug 2012 02:30:14 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1/nj2xBY/3nKzLhb7GQEz5QnnW12lF19//8WYBUtp Rtv5v6xfirw6zw Message-ID: <1344321010.6968.10.camel@marge.simpson.net> Subject: Re: [parch] sched: task_times() explosion avoidance for tasks with > 2^32 acrued ticks From: Mike Galbraith To: LKML Cc: Peter Zijlstra Date: Tue, 07 Aug 2012 08:30:10 +0200 In-Reply-To: <1344261539.6853.1.camel@marge.simpson.net> References: <1344261539.6853.1.camel@marge.simpson.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Wrong xx. sched: task_times() explosion avoidance for tasks with > 2^32 accrued ticks If stime + utime > 2^32, and lower 32 are 0 when user calls getrusage(), you've got a dead box. Signed-off-by: Mike Galbraith kernel/sched/core.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 82ad284..b0b0d29 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3155,7 +3155,7 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) u64 temp = (__force u64) rtime; temp *= (__force u64) utime; - do_div(temp, (__force u32) total); + temp = div64_u64(temp, (__force u64) total); utime = (__force cputime_t) temp; } else utime = rtime; @@ -3188,7 +3188,7 @@ void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) u64 temp = (__force u64) rtime; temp *= (__force u64) cputime.utime; - do_div(temp, (__force u32) total); + temp = div64_u64(temp, (__force u64) total); utime = (__force cputime_t) temp; } else utime = rtime;