From nobody Tue Feb 10 05:27:34 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 1658FC77B75 for ; Mon, 15 May 2023 06:39:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239960AbjEOGjL (ORCPT ); Mon, 15 May 2023 02:39:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229898AbjEOGjI (ORCPT ); Mon, 15 May 2023 02:39:08 -0400 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48B77114 for ; Sun, 14 May 2023 23:39:06 -0700 (PDT) Received: by mail-pl1-x62a.google.com with SMTP id d9443c01a7336-1aad5245571so84490045ad.1 for ; Sun, 14 May 2023 23:39:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1684132746; x=1686724746; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=W70DiGj/q2nP8jtGasv9F9p6lMGC6Cif6Ya2AzHk0NQ=; b=SE71g8zH4uEQnUiO+eEH/bgF9Hw2s0M0nKzDPCQ5MzGjcOL+bK+Y353hzsKMSnMvI3 /z7iqNfNNFRaPRdSnHk1uONT7hgpCOyZgkDdi43f00JSVIanIZi7nkAdZ2mqB5d1QvZI /NLcUYX0YQBXzDuVPiPk2eeJEmpWAefACnLxFBMAFlM6KPIeJU59oz6Pn+MbuHOkGUTd g6VU8NdiA21qzKtniVfvAq0zeH3LBPTzHp8YXIIn/OFBpohU8V+TVx8d/o01oijnrzZP 4hZ+InzPY1XcHts0s5Kl6PZIBFc5edTFBN0Caxm/0bCnkDj2Dtuc3biIKOjTGE0B1SFG VRDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684132746; x=1686724746; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=W70DiGj/q2nP8jtGasv9F9p6lMGC6Cif6Ya2AzHk0NQ=; b=fzgBjWc9JRk1uUr1iPe1ImpQsOKN5lK8LW5xzokqnObfu8OwgOmvLvAWiGSp+5MoGH /UXpXHxrqMOqWkDqoS9o/P4qW+Vx3ZywfCOjzgtCf/MV15+QIV7PnoMZqdwNPnHAOQqx nLo0SZ7ev5XFtlm8HaDPU6ljOlK+D1FiuDOD7Gf343Rqi557hwUmHwQnga1KAUwK4eHu eEGGx4QMudboDNV2NTKWN4uqk/FIr2J+UBpK7mc80ecdMu+3VOjn8EFpJUI4uJdY5EXD tYY2t3moIPqKwhMQMbevWSOZZNYM52CbCxdEn5b2oC1j6u76AIFJkwJfEOhws2cGr4yB 9f5A== X-Gm-Message-State: AC+VfDxOl+8ugbp1NGjTgt8VXaue+e91jAppJhoudr/DBuE4t+qP/+dU QmIqd6EDpc0CQHbIkU0RVHDlDg== X-Google-Smtp-Source: ACHHUZ6f0qpiolJypED7ziKzmzZ9Xo2ide3GNCJLwOxgpMFS3rHdZMuE0FV+qZumrbDua2SXkxVxpA== X-Received: by 2002:a17:903:120d:b0:1aa:f53a:5e47 with SMTP id l13-20020a170903120d00b001aaf53a5e47mr39324265plh.16.1684132745766; Sun, 14 May 2023 23:39:05 -0700 (PDT) Received: from C02G87K0MD6R.bytedance.net ([139.177.225.228]) by smtp.gmail.com with ESMTPSA id t1-20020a170902a5c100b001ab01598f40sm12608543plq.173.2023.05.14.23.39.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 14 May 2023 23:39:05 -0700 (PDT) From: Hao Jia To: mingo@redhat.com, peterz@infradead.org, mingo@kernel.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, mgorman@techsingularity.net Cc: linux-kernel@vger.kernel.org, Hao Jia Subject: [PATCH v3 1/4] sched/core: Fixed missing rq clock update before calling set_rq_offline() Date: Mon, 15 May 2023 14:38:45 +0800 Message-Id: <20230515063848.77947-2-jiahao.os@bytedance.com> X-Mailer: git-send-email 2.37.0 (Apple Git-136) In-Reply-To: <20230515063848.77947-1-jiahao.os@bytedance.com> References: <20230515063848.77947-1-jiahao.os@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This is triggered during cpu offline when CONFIG_CPU_FREQ is enabled and cpufreq is set to powersave: Reviewed-by: Vincent Guittot ------------[ cut here ]------------ rq->clock_update_flags < RQCF_ACT_SKIP WARNING: CPU: 24 PID: 754 at kernel/sched/sched.h:1496 enqueue_top_rt_rq+0x139/0x160 Call Trace: ? intel_pstate_update_util+0x3b0/0x3b0 rq_offline_rt+0x1b7/0x250 set_rq_offline.part.120+0x28/0x60 rq_attach_root+0xc4/0xd0 cpu_attach_domain+0x3dc/0x7f0 ? __schedule+0x65e/0x1310 partition_sched_domains_locked+0x2a5/0x3c0 rebuild_sched_domains_locked+0x477/0x830 ? percpu_rwsem_wait+0x140/0x140 rebuild_sched_domains+0x1b/0x30 cpuset_hotplug_workfn+0x2ca/0xc90 ? balance_push+0x56/0x120 ? _raw_spin_unlock+0x15/0x30 ? finish_task_switch+0x98/0x2f0 ? __switch_to+0x116/0x410 ? __schedule+0x65e/0x1310 ? internal_add_timer+0x42/0x60 ? _raw_spin_unlock_irqrestore+0x23/0x40 ? add_timer_on+0xd5/0x130 process_one_work+0x1bc/0x3d0 worker_thread+0x4c/0x380 ? preempt_count_add+0x56/0xa0 ? rescuer_thread+0x310/0x310 kthread+0xe6/0x110 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 More detailed key function call graph: rq_offline_rt() __disable_runtime() sched_rt_rq_enqueue() enqueue_top_rt_rq() cpufreq_update_util() <-- depends on CONFIG_CPU_FREQ data->func(data, *rq_clock(rq)*, flags) intel_pstate_update_util() <-- powersave policy callback functi= on Before calling set_rq_offline() we need to update the rq clock to avoid using the old rq clock, and use rq_lock_irqsave()/rq_unlock_irqrestore() to replace raw_spin_rq_lock_irqsave()/raw_spin_rq_unlock_irqrestore() to ensure that rq->clock_update_flags are cleared before updating the rq clock. Steps to reproduce: 1. Enable CONFIG_SMP and CONFIG_CPU_FREQ when compiling the kernel 2. echo 1 > /sys/kernel/debug/clear_warn_once 3. cpupower -c all frequency-set -g powersave 4. Run some rt tasks e.g. Create 5*n rt (100% running) tasks (on a system with n CPUs) 5. Offline cpu one by one until the warninng is triggered Signed-off-by: Hao Jia --- kernel/sched/topology.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 6682535e37c8..b89497696880 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -487,15 +487,17 @@ static void free_rootdomain(struct rcu_head *rcu) void rq_attach_root(struct rq *rq, struct root_domain *rd) { struct root_domain *old_rd =3D NULL; - unsigned long flags; + struct rq_flags rf; =20 - raw_spin_rq_lock_irqsave(rq, flags); + rq_lock_irqsave(rq, &rf); =20 if (rq->rd) { old_rd =3D rq->rd; =20 - if (cpumask_test_cpu(rq->cpu, old_rd->online)) + if (cpumask_test_cpu(rq->cpu, old_rd->online)) { + update_rq_clock(rq); set_rq_offline(rq); + } =20 cpumask_clear_cpu(rq->cpu, old_rd->span); =20 @@ -515,7 +517,7 @@ void rq_attach_root(struct rq *rq, struct root_domain *= rd) if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) set_rq_online(rq); =20 - raw_spin_rq_unlock_irqrestore(rq, flags); + rq_unlock_irqrestore(rq, &rf); =20 if (old_rd) call_rcu(&old_rd->rcu, free_rootdomain); --=20 2.37.0