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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 1018BC54FCB for ; Thu, 23 Apr 2020 13:38:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5E162077D for ; Thu, 23 Apr 2020 13:38:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728407AbgDWNiQ (ORCPT ); Thu, 23 Apr 2020 09:38:16 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:57284 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728153AbgDWNiP (ORCPT ); Thu, 23 Apr 2020 09:38:15 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01419;MF=changhuaixin@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0TwR4C8H_1587649090; Received: from localhost(mailfrom:changhuaixin@linux.alibaba.com fp:SMTPD_---0TwR4C8H_1587649090) by smtp.aliyun-inc.com(127.0.0.1); Thu, 23 Apr 2020 21:38:13 +0800 From: Huaixin Chang To: bsegall@google.com Cc: changhuaixin@linux.alibaba.com, chiluk+linux@indeed.com, linux-kernel@vger.kernel.org, mingo@redhat.com, pauld@redhead.com, peterz@infradead.org, vincent.guittot@linaro.org Subject: [PATCH] sched: Defend cfs and rt bandwidth quota against overflow Date: Thu, 23 Apr 2020 21:37:52 +0800 Message-Id: <20200423133752.12787-1-changhuaixin@linux.alibaba.com> X-Mailer: git-send-email 2.14.4.44.g2045bb6 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- kernel/sched/core.c | 8 ++++++++ kernel/sched/rt.c | 9 +++++++++ kernel/sched/sched.h | 2 ++ 3 files changed, 19 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3a61a3b8eaa9..0be1782e15c9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7390,6 +7390,8 @@ 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); @@ -7417,6 +7419,12 @@ 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..7ba49625cdbd 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2569,6 +2569,9 @@ static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) return ret; } +/* More than 4 hours if BW_SHIFT equals 20. */ +static const u64 max_rt_runtime = MAX_BW; + static int tg_set_rt_bandwidth(struct task_group *tg, u64 rt_period, u64 rt_runtime) { @@ -2585,6 +2588,12 @@ 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) 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); -- 2.14.4.44.g2045bb6