From patchwork Fri Jun 19 14:31:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 223974 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 CB586C433DF for ; Fri, 19 Jun 2020 15:49:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB76820809 for ; Fri, 19 Jun 2020 15:49:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592581769; bh=Loi2gZDSbCrROCbcd1K6A4WD/voItVzsRtt0yXur1NA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bZ9sHMDH2thJPBqZkWMKITl2UfEKJA0JgncCR6Ugja6p76CgjR+Kq/PQuc4ugBOIK RMWfYrrtT4dTZ8B8eZi+S9tCtTHJ3YloncWnX/zlfi1zETIoLX2UpLaZJaaTSEM/AP hEMVaLCwTYkNMZqsN+tmu2SczuQCeJ/QA9zrKcvo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392318AbgFSPt2 (ORCPT ); Fri, 19 Jun 2020 11:49:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:56980 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393377AbgFSPZM (ORCPT ); Fri, 19 Jun 2020 11:25:12 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C3DA521548; Fri, 19 Jun 2020 15:25:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592580311; bh=Loi2gZDSbCrROCbcd1K6A4WD/voItVzsRtt0yXur1NA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hth2z620PAZAvqTJK3sJ6nPkfutfrhSA9K+8C/gAeV/+T5R/fnprKPX01Y75dl7Ax 4/g/R9aBYGDCZiGszDT/etJ3WYzKXf4EZPu1OfidVroXZRtQ+yPx2oUcWKOMBS4v4s O4jU8Gk5aawGZOxk6p82rF/j1TPnPd1Q1sU7NQwY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Huaixin Chang , "Peter Zijlstra (Intel)" , Ben Segall , Sasha Levin Subject: [PATCH 5.7 201/376] sched: Defend cfs and rt bandwidth quota against overflow Date: Fri, 19 Jun 2020 16:31:59 +0200 Message-Id: <20200619141719.857518312@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141710.350494719@linuxfoundation.org> References: <20200619141710.350494719@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Huaixin Chang [ Upstream commit d505b8af58912ae1e1a211fabc9995b19bd40828 ] When users write some huge number into cpu.cfs_quota_us or cpu.rt_runtime_us, overflow might happen during to_ratio() shifts of schedulable checks. to_ratio() could be altered to avoid unnecessary internal overflow, but min_cfs_quota_period is less than 1 << BW_SHIFT, so a cutoff would still be needed. Set a cap MAX_BW for cfs_quota_us and rt_runtime_us to prevent overflow. Signed-off-by: Huaixin Chang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Ben Segall Link: https://lkml.kernel.org/r/20200425105248.60093-1-changhuaixin@linux.alibaba.com Signed-off-by: Sasha Levin --- kernel/sched/core.c | 8 ++++++++ kernel/sched/rt.c | 12 +++++++++++- kernel/sched/sched.h | 2 ++ 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0bbf387d0f19..5eccfb816d23 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7386,6 +7386,8 @@ static DEFINE_MUTEX(cfs_constraints_mutex); const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ static const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ +/* More than 203 days if BW_SHIFT equals 20. */ +static const u64 max_cfs_runtime = MAX_BW * NSEC_PER_USEC; static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); @@ -7413,6 +7415,12 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) if (period > max_cfs_quota_period) return -EINVAL; + /* + * Bound quota to defend quota against overflow during bandwidth shift. + */ + if (quota != RUNTIME_INF && quota > max_cfs_runtime) + return -EINVAL; + /* * Prevent race between setting of cfs_rq->runtime_enabled and * unthrottle_offline_cfs_rqs(). diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index df11d88c9895..6d60ba21ed29 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -9,6 +9,8 @@ int sched_rr_timeslice = RR_TIMESLICE; int sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE; +/* More than 4 hours if BW_SHIFT equals 20. */ +static const u64 max_rt_runtime = MAX_BW; static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun); @@ -2585,6 +2587,12 @@ static int tg_set_rt_bandwidth(struct task_group *tg, if (rt_period == 0) return -EINVAL; + /* + * Bound quota to defend quota against overflow during bandwidth shift. + */ + if (rt_runtime != RUNTIME_INF && rt_runtime > max_rt_runtime) + return -EINVAL; + mutex_lock(&rt_constraints_mutex); err = __rt_schedulable(tg, rt_period, rt_runtime); if (err) @@ -2702,7 +2710,9 @@ static int sched_rt_global_validate(void) return -EINVAL; if ((sysctl_sched_rt_runtime != RUNTIME_INF) && - (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) + ((sysctl_sched_rt_runtime > sysctl_sched_rt_period) || + ((u64)sysctl_sched_rt_runtime * + NSEC_PER_USEC > max_rt_runtime))) return -EINVAL; return 0; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index db3a57675ccf..1f58677a8f23 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1918,6 +1918,8 @@ extern void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se); #define BW_SHIFT 20 #define BW_UNIT (1 << BW_SHIFT) #define RATIO_SHIFT 8 +#define MAX_BW_BITS (64 - BW_SHIFT) +#define MAX_BW ((1ULL << MAX_BW_BITS) - 1) unsigned long to_ratio(u64 period, u64 runtime); extern void init_entity_runnable_average(struct sched_entity *se);