From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98986FA372C for ; Fri, 8 Nov 2019 07:33:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7499B214DB for ; Fri, 8 Nov 2019 07:33:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729964AbfKHHdP (ORCPT ); Fri, 8 Nov 2019 02:33:15 -0500 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:48524 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725900AbfKHHdP (ORCPT ); Fri, 8 Nov 2019 02:33:15 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07417;MF=xiejingfeng@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0ThU0D.W_1573198392; Received: from 30.5.113.47(mailfrom:xiejingfeng@linux.alibaba.com fp:SMTPD_---0ThU0D.W_1573198392) by smtp.aliyun-inc.com(127.0.0.1); Fri, 08 Nov 2019 15:33:13 +0800 User-Agent: Microsoft-MacOutlook/10.1f.0.191103 Date: Fri, 08 Nov 2019 15:33:24 +0800 Subject: [PATCH] psi:fix divide by zero in psi_update_stats From: tim To: Johannes Weiner , Ingo Molnar , Peter Zijlstra CC: Message-ID: Thread-Topic: [PATCH] psi:fix divide by zero in psi_update_stats Mime-version: 1.0 Content-type: text/plain; charset="UTF-8" Content-transfer-encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In psi_update_stats, it is possible that period has value like 0xXXXXXXXX00000000 where the lower 32 bit is 0, then it calls div_u64 which truncates u64 period to u32, results in zero divisor. Use div64_u64() instead of div_u64() if the divisor is u64 to avoid truncation to 32-bit on 64-bit platforms. Signed-off-by: xiejingfeng --- kernel/sched/psi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 517e3719027e..399d6f106de5 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -291,7 +291,7 @@ static void calc_avgs(unsigned long avg[3], int missed_periods, } /* Sample the most recent active period */ - pct = div_u64(time * 100, period); + pct = div64_u64(time * 100, period); pct *= FIXED_1; avg[0] = calc_load(avg[0], EXP_10s, pct); avg[1] = calc_load(avg[1], EXP_60s, pct); -- 2.14.4.44.g2045bb