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=-5.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 291D7C3F2D2 for ; Fri, 28 Feb 2020 16:35:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EEFF52468E for ; Fri, 28 Feb 2020 16:35:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="sEJi1F7K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726765AbgB1Qfv (ORCPT ); Fri, 28 Feb 2020 11:35:51 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:55894 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726046AbgB1Qfv (ORCPT ); Fri, 28 Feb 2020 11:35:51 -0500 Received: by mail-wm1-f66.google.com with SMTP id q9so3802736wmj.5 for ; Fri, 28 Feb 2020 08:35:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=HcG/EOqr8+CrfwSO/n77ulX+/pcSO4hIkOvdzBU4ykI=; b=sEJi1F7K5C+WPjvqrp9HyIGTw2H29ojkfm6wa2Y8BrBZ6IDEgfpQX014Yj00Hjp3am D0ndUXBuV8xdg7vnbJea8LEch/4ncITWTbIIbTh0B9FPLPJyK/WxgkI15BHguHlIFb1U iL8c1dGxMO1t0uauBjyIgLI2lKgUbxiJh/MsHbQKt/aqowgM8b24xmeDQim/Utq+i0ty IOD6/gFjloEH9FTzrkpHXzb5+oDNK9nxvQ9QxsXPSCj3/lNZSvpk2jwerbx97hK/m4/J BJVxgIjNVMk5xD6u30d3PZ2mPJDn9jR8XMc1CrljcD45WvV/NQ50UICwJ7uYxZFXYjST zhPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=HcG/EOqr8+CrfwSO/n77ulX+/pcSO4hIkOvdzBU4ykI=; b=t3am9KSohgCJUGr41jMJgPMlBTpjllTIzgLe5tiWYBQFAiXXz7tIVri9O12/QaW4Cn NbONO6p8b0FGH11oETWqQotdQUEXcWcdDAYg0IyTf2NtRSW8fxLTKlRkkNen9ZtIRjh3 6TP5938sbIklnqp64diXKiM1kpZwhFi3qXBgy0ScXiFbmTWsUsixYgVZzsTrgKANBfsb B85UNQazmqh82f7SuH22lmKILxXDeaaWIeiDGG3jFooUWV+NiFZqZrsqPBL1SUrsNw/Q 7ivHko1mAk/gQwmzg/QkeAoXwM5XykEbZjn/El/JHAqFvJJc9Rr2DHYtUshRghp8ZFAX VFlg== X-Gm-Message-State: APjAAAVc6wJHN9GJuFD3m3VtmE4iyXFLJhgpUj30rulxpgd1bH/jbIP4 TB1CzIdoLBdm83o6CsFniQEOng== X-Google-Smtp-Source: APXvYqxGJidQ2k3iW7VpU0ESuoj1p6lTJ5v2plfr2HD4Loc/kWeaZpO3URuGldRyIxcAcgk6NjvbPQ== X-Received: by 2002:a7b:cb97:: with SMTP id m23mr5343325wmi.37.1582907748312; Fri, 28 Feb 2020 08:35:48 -0800 (PST) Received: from vingu-book ([2a01:e0a:f:6020:9522:3a6c:498:7b7d]) by smtp.gmail.com with ESMTPSA id r6sm13392923wrq.92.2020.02.28.08.35.46 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 28 Feb 2020 08:35:47 -0800 (PST) Date: Fri, 28 Feb 2020 17:35:45 +0100 From: Vincent Guittot To: Christian Borntraeger Cc: Ingo Molnar , Peter Zijlstra , "linux-kernel@vger.kernel.org" Subject: Re: 5.6-rc3: WARNING: CPU: 48 PID: 17435 at kernel/sched/fair.c:380 enqueue_task_fair+0x328/0x440 Message-ID: <20200228163545.GA18662@vingu-book> References: <1a607a98-f12a-77bd-2062-c3e599614331@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le vendredi 28 févr. 2020 à 16:42:27 (+0100), Christian Borntraeger a écrit : > > > On 28.02.20 16:37, Vincent Guittot wrote: > > On Fri, 28 Feb 2020 at 16:08, Christian Borntraeger > > wrote: > >> > >> Also happened with 5.4: > >> Seems that I just happen to have an interesting test workload/system size interaction > >> on a newly installed system that triggers this. > > > > you will probably go back to 5.1 which is the version where we put > > back the deletion of unused cfs_rq from the list which can trigger the > > warning: > > commit 039ae8bcf7a5 : (Fix O(nr_cgroups) in the load balancing path) > > > > AFAICT, we haven't changed this since > > So you do know what is the problem? If not is there any debug option or > patch that I could apply to give you more information? No I don't know what is happening. Your test probably goes through an unexpected path Would it be difficult for me to reproduce your test env ? There is an optimization in the code which could generate problem if assumption is not true. Could you try the patch below ? --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3c8a379c357e..beb773c23e7d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4035,8 +4035,8 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) __enqueue_entity(cfs_rq, se); se->on_rq = 1; + list_add_leaf_cfs_rq(cfs_rq); if (cfs_rq->nr_running == 1) { - list_add_leaf_cfs_rq(cfs_rq); check_enqueue_throttle(cfs_rq); } } -- 2.17.1 >