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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 D4330C43603 for ; Tue, 17 Dec 2019 12:40:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0CA721582 for ; Tue, 17 Dec 2019 12:40:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728270AbfLQMkD (ORCPT ); Tue, 17 Dec 2019 07:40:03 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:55265 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728157AbfLQMkB (ORCPT ); Tue, 17 Dec 2019 07:40:01 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1ihC8m-0001oW-Dw; Tue, 17 Dec 2019 13:39:52 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 922521C2A3B; Tue, 17 Dec 2019 13:39:51 +0100 (CET) Date: Tue, 17 Dec 2019 12:39:51 -0000 From: "tip-bot2 for Johannes Weiner" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/urgent] psi: Fix a division error in psi poll() Cc: Johannes Weiner , "Peter Zijlstra (Intel)" , Suren Baghdasaryan , Jingfeng Xie , x86 , LKML In-Reply-To: <20191203183524.41378-3-hannes@cmpxchg.org> References: <20191203183524.41378-3-hannes@cmpxchg.org> MIME-Version: 1.0 Message-ID: <157658639149.30329.11554714780751480566.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/urgent branch of tip: Commit-ID: c3466952ca1514158d7c16c9cfc48c27d5c5dc0f Gitweb: https://git.kernel.org/tip/c3466952ca1514158d7c16c9cfc48c27d5c5dc0f Author: Johannes Weiner AuthorDate: Tue, 03 Dec 2019 13:35:24 -05:00 Committer: Peter Zijlstra CommitterDate: Tue, 17 Dec 2019 13:32:48 +01:00 psi: Fix a division error in psi poll() The psi window size is a u64 an can be up to 10 seconds right now, which exceeds the lower 32 bits of the variable. We currently use div_u64 for it, which is meant only for 32-bit divisors. The result is garbage pressure sampling values and even potential div0 crashes. Use div64_u64. Signed-off-by: Johannes Weiner Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Suren Baghdasaryan Cc: Jingfeng Xie Link: https://lkml.kernel.org/r/20191203183524.41378-3-hannes@cmpxchg.org --- 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 970db46..ce8f674 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -482,7 +482,7 @@ static u64 window_update(struct psi_window *win, u64 now, u64 value) u32 remaining; remaining = win->size - elapsed; - growth += div_u64(win->prev_growth * remaining, win->size); + growth += div64_u64(win->prev_growth * remaining, win->size); } return growth;