From nobody Tue Apr 7 03:49:09 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1423BECAAD1 for ; Wed, 31 Aug 2022 06:49:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230049AbiHaGtd (ORCPT ); Wed, 31 Aug 2022 02:49:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229570AbiHaGtb (ORCPT ); Wed, 31 Aug 2022 02:49:31 -0400 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E776EA1D57 for ; Tue, 30 Aug 2022 23:49:29 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045170;MF=cruzzhao@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0VNq13Hu_1661928558; Received: from rt2b04371.sqa.tbc.tbsite.net(mailfrom:CruzZhao@linux.alibaba.com fp:SMTPD_---0VNq13Hu_1661928558) by smtp.aliyun-inc.com; Wed, 31 Aug 2022 14:49:26 +0800 From: Cruz Zhao To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH] sched/core: Fix the bug that sched_core_find() may return throttled task Date: Wed, 31 Aug 2022 14:49:18 +0800 Message-Id: <1661928558-108473-1-git-send-email-CruzZhao@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When a cfs_rq is throttled, the cookie'd task in this cfs_rq wouldn't dequeue from the core tree, and sched_core_find() may return this task, which will result that the throttled task running on the cpu. To resolve this problem, we pick the first cookie matched task and unthrottled task. Signed-off-by: Cruz Zhao --- kernel/sched/core.c | 6 ++++++ kernel/sched/fair.c | 7 +++++++ kernel/sched/sched.h | 1 + 3 files changed, 14 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b604223..a34acd0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -271,6 +271,12 @@ static struct task_struct *sched_core_find(struct rq *= rq, unsigned long cookie) struct rb_node *node; =20 node =3D rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp); + while (node && task_throttled(__node_2_sc(node))) { + node =3D rb_next(node); + if (node && cookie !=3D __node_2_sc(node)->core_cookie) + node =3D NULL; + } + /* * The idle task always matches any cookie! */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index cf3300b..4878a25 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11563,6 +11563,13 @@ bool cfs_prio_less(struct task_struct *a, struct t= ask_struct *b, bool in_fi) =20 return delta > 0; } + +inline int task_throttled(struct task_struct *p) +{ + struct cfs_rq *cfs_rq =3D cfs_rq_of(&p->se); + + return cfs_rq_throttled(cfs_rq); +} #else static inline void task_tick_core(struct rq *rq, struct task_struct *curr)= {} #endif diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index f616e0c..c6e3955 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1285,6 +1285,7 @@ static inline bool sched_core_enqueued(struct task_st= ruct *p) =20 extern void sched_core_get(void); extern void sched_core_put(void); +extern int task_throttled(struct task_struct *p); =20 #else /* !CONFIG_SCHED_CORE */ =20 --=20 1.8.3.1