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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 874A9C4360F for ; Wed, 27 Feb 2019 08:10:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 44F4C218D9 for ; Wed, 27 Feb 2019 08:10:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="G8FaNp6O" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729693AbfB0IKZ (ORCPT ); Wed, 27 Feb 2019 03:10:25 -0500 Received: from forwardcorp1j.cmail.yandex.net ([5.255.227.105]:37991 "EHLO forwardcorp1j.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729249AbfB0IKW (ORCPT ); Wed, 27 Feb 2019 03:10:22 -0500 Received: from mxbackcorp1j.mail.yandex.net (mxbackcorp1j.mail.yandex.net [IPv6:2a02:6b8:0:1619::162]) by forwardcorp1j.cmail.yandex.net (Yandex) with ESMTP id A5EF821576; Wed, 27 Feb 2019 11:10:19 +0300 (MSK) Received: from smtpcorp1j.mail.yandex.net (smtpcorp1j.mail.yandex.net [2a02:6b8:0:1619::137]) by mxbackcorp1j.mail.yandex.net (nwsmtp/Yandex) with ESMTP id 9wiH75Up3X-AJQGrPHt; Wed, 27 Feb 2019 11:10:19 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1551255019; bh=nHxLRba8hwVikPHwTuKeE6G1NROyk72EdJ/rfD/Ha8s=; h=Message-ID:References:Date:To:From:Subject:In-Reply-To; b=G8FaNp6Oft27WQ2YD7EiIoa+ZRJ4wcTx/OUdy0HT0ZLbEWp0Bh3jXQ2EdaVsZgr4F BqODNh6yxq/zY03qKU84a88nMxsGfHMWM7mI34vfFmr182866fqgjdUq+OIkc3lBLS UfCZN4eCNXnbd7IazfCuhq6bdLvziuAGsDi6TCBc= Authentication-Results: mxbackcorp1j.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-red.dhcp.yndx.net (dynamic-red.dhcp.yndx.net [2a02:6b8:0:40c:8865:6f76:e76b:3fab]) by smtpcorp1j.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id AO5zLD244o-AJ9u8gKl; Wed, 27 Feb 2019 11:10:19 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Subject: [PATCH 2/3] sched/core: handle overflow in cpu_shares_write_u64 From: Konstantin Khlebnikov To: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org Date: Wed, 27 Feb 2019 11:10:18 +0300 Message-ID: <155125501891.293431.3345233332801109696.stgit@buzz> In-Reply-To: <155125501739.293431.5252197504404771496.stgit@buzz> References: <155125501739.293431.5252197504404771496.stgit@buzz> User-Agent: StGit/0.17.1-dirty 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 Bit shift in scale_load() could overflow shares. This patch saturates it to MAX_SHARES like following sched_group_set_shares(). Example: # echo 9223372036854776832 > cpu.shares # cat cpu.shares Before patch: 1024 After pattch: 262144 Signed-off-by: Konstantin Khlebnikov --- kernel/sched/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d8d76a65cfdd..a626fbd9fdc7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6502,6 +6502,8 @@ static void cpu_cgroup_attach(struct cgroup_taskset *tset) static int cpu_shares_write_u64(struct cgroup_subsys_state *css, struct cftype *cftype, u64 shareval) { + if (shareval > scale_load_down(ULONG_MAX)) + shareval = MAX_SHARES; return sched_group_set_shares(css_tg(css), scale_load(shareval)); }