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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 B1CE2C43142 for ; Tue, 26 Jun 2018 16:17:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F96026D98 for ; Tue, 26 Jun 2018 16:17:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6F96026D98 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de 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 S1752358AbeFZQRF (ORCPT ); Tue, 26 Jun 2018 12:17:05 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:50505 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752145AbeFZQRE (ORCPT ); Tue, 26 Jun 2018 12:17:04 -0400 Received: from hsi-kbw-5-158-153-52.hsi19.kabel-badenwuerttemberg.de ([5.158.153.52] helo=somnus.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fXqeL-00057G-LI; Tue, 26 Jun 2018 18:17:01 +0200 Date: Tue, 26 Jun 2018 18:16:04 +0200 (CEST) From: Anna-Maria Gleixner To: linux-kernel@vger.kernel.org cc: "Paul E. McKenney" , Thomas Gleixner , Frederic Weisbecker , Peter Zijlstra Subject: sched/core warning triggers on rcu torture test Message-ID: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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