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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, USER_AGENT_MUTT 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 5DE9FC43142 for ; Wed, 27 Jun 2018 11:29:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12FB8262D7 for ; Wed, 27 Jun 2018 11:29:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="RIDp9hDY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 12FB8262D7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753561AbeF0L3l (ORCPT ); Wed, 27 Jun 2018 07:29:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:45090 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752063AbeF0L3k (ORCPT ); Wed, 27 Jun 2018 07:29:40 -0400 Received: from localhost (LFbn-NCY-1-193-82.w83-194.abo.wanadoo.fr [83.194.41.82]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2F827262C8; Wed, 27 Jun 2018 11:29:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1530098979; bh=9cKcjtTUr9r9vDvIynHgoGZdEkfTT8F5BJN5GXji3D8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RIDp9hDYlF6YBV/hWoKBLmFBN1Sw4+qw3H7WXQDLmhRPJiyJ/a0zyp47iHHbozvLZ IlNvTOiauizX84xft+2I57R9DbmbcHDTYmXmjdm9ssLCuXvMoCM+4NUax5Slg1mouc 1Ip570iqpzNf29MyHZms268kvYBfJb2Fl68/2egE= Date: Wed, 27 Jun 2018 13:29:36 +0200 From: Frederic Weisbecker To: Anna-Maria Gleixner Cc: linux-kernel@vger.kernel.org, "Paul E. McKenney" , Thomas Gleixner , Frederic Weisbecker , Peter Zijlstra Subject: Re: sched/core warning triggers on rcu torture test Message-ID: <20180627112935.GC10102@lerouge> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 26, 2018 at 06:16:04PM +0200, Anna-Maria Gleixner wrote: > Hi, > > during rcu torture tests (TREE04 and TREE07) I noticed, that a > WARN_ON_ONCE() in sched core triggers on a recent 4.18-rc2 based > kernel (6f0d349d922b ("Merge > git://git.kernel.org/pub/scm/linux/kernel/git/davem/net")) as well as > on a 4.17.3. > > I'm running the tests on a machine with 144 cores: > > tools/testing/selftests/rcutorture/bin/kvm.sh --cpus 144 --duration 120 --configs "9*TREE07" > tools/testing/selftests/rcutorture/bin/kvm.sh --cpus 144 --duration 120 --configs "18*TREE04" > > > The warning was introduced by commit d84b31313ef8 ("sched/isolation: > Offload residual 1Hz scheduler tick"). > > > Output looks similar for all tests I did (this one is the output of > the 4.18-rc2 based kernel): > > WARNING: CPU: 11 PID: 906 at kernel/sched/core.c:3138 sched_tick_remote+0xb6/0xc0 > Modules linked in: > CPU: 11 PID: 906 Comm: kworker/u32:3 Not tainted 4.18.0-rc2+ #1 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 > Workqueue: events_unbound sched_tick_remote > RIP: 0010:sched_tick_remote+0xb6/0xc0 > Code: e8 0f 06 b8 00 c6 03 00 fb eb 9d 8b 43 04 85 c0 75 8d 48 8b 83 e0 0a 00 00 48 85 c0 75 81 eb 88 48 89 df e8 bc fe ff ff eb aa <0f> 0b eb c5 66 0f 1f 44 00 00 bf 17 00 00 00 e8 b6 2e fe ff 0f b6 > Call Trace: > process_one_work+0x1df/0x3b0 > worker_thread+0x44/0x3d0 > kthread+0xf3/0x130 > ? set_worker_desc+0xb0/0xb0 > ? kthread_create_worker_on_cpu+0x70/0x70 > ret_from_fork+0x35/0x40 > ---[ end trace 7c99b83eb0ec64e8 ]--- > > > Do you need some more information? > > > Thanks, > > Anna-Maria Ok so now I reproduce it immediately after the boot, time for me to debug :-) Thanks.