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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 3703CC4338F for ; Wed, 28 Jul 2021 15:55:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A2A9603E7 for ; Wed, 28 Jul 2021 15:55:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237078AbhG1PzK (ORCPT ); Wed, 28 Jul 2021 11:55:10 -0400 Received: from foss.arm.com ([217.140.110.172]:59084 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229880AbhG1PzJ (ORCPT ); Wed, 28 Jul 2021 11:55:09 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CB34F1FB; Wed, 28 Jul 2021 08:55:07 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EBAD33F70D; Wed, 28 Jul 2021 08:55:06 -0700 (PDT) Subject: Re: WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453 To: Bruno Goncalves , CKI Project , linux-kernel@vger.kernel.org Cc: nathan@kernel.org, Memory Management References: From: Dietmar Eggemann Message-ID: Date: Wed, 28 Jul 2021 17:55:05 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/07/2021 15:11, Bruno Goncalves wrote: > Hello, > > Since this commit (Commit: 45312bd762d3 - Merge tag 'zonefs-5.14-rc2') > we started to see the following call trace, it seems to be > reproducible only on aarch64. It should happen on platforms using a slow-switching cpufreq driver. Only in this case you have n (depends on nbr of frequency domains) special-purpose DL threads when using schedutil CPUFreq governor: root@juno: ps -eTo comm,pid,pri,class | grep sugov sugov:0 132 140 DLN sugov:1 134 140 DLN > > [ 384.485614] ------------[ cut here ]------------ > [ 384.490227] rq->clock_update_flags < RQCF_ACT_SKIP > [ 384.490232] WARNING: CPU: 112 PID: 2041 at > kernel/sched/sched.h:1453 sub_running_bw.isra.0+0x190/0x1a0 > [ 384.504312] Modules linked in: mlx5_ib ib_uverbs ib_core rfkill > sunrpc acpi_ipmi ipmi_ssif mlx5_core mlxfw psample ipmi_devintf > arm_cmn ipmi_msghandler arm_dsu_pmu cppc_cpufreq acpi_tad vfat fat > fuse zram ip_tables x_tables xfs crct10dif_ce ghash_ce ast > i2c_algo_bit drm_vram_helper sbsa_gwdt drm_kms_helper syscopyarea > sysfillrect sysimgblt fb_sys_fops cec drm_ttm_helper ttm nvme > nvme_core drm xgene_hwmon aes_neon_bs > [ 384.541165] CPU: 112 PID: 2041 Comm: sugov:112 Tainted: G W > 5.14.0-rc1 #1 > [ 384.549244] Hardware name: WIWYNN Mt.Jade Server System > B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP: > 1.06.20210526) 2021/05/26 > [ 384.561922] pstate: 404000c9 (nZcv daIF +PAN -UAO -TCO BTYPE=--) > [ 384.567918] pc : sub_running_bw.isra.0+0x190/0x1a0 > [ 384.572698] lr : sub_running_bw.isra.0+0x190/0x1a0 > [ 384.577477] sp : ffff800024c4bb20 > [ 384.580779] x29: ffff800024c4bb20 x28: 0000000000000000 x27: ffffb9a9bbe1d200 > [ 384.587904] x26: 0000000000000074 x25: 0000000000000011 x24: ffffb9a9bdff9000 > [ 384.595029] x23: ffff07ffb36fcaa0 x22: ffff401ee09b65c0 x21: ffffb9a9bbe1de00 > [ 384.602153] x20: ffff401ee09a3360 x19: ffff401ee09b6f58 x18: 0000000000000000 > [ 384.609277] x17: ffff867522f0c000 x16: ffff800010384000 x15: 0000000000000030 > [ 384.616401] x14: 0000000000000000 x13: 50494b535f544341 x12: 5f46435152203c20 > [ 384.623526] x11: ffff401ee04b0ea8 x10: ffff401ee021e068 x9 : ffffb9a9bbe4214c > [ 384.630650] x8 : 0000000000010ea8 x7 : ffff401ee01e0000 x6 : 0000000000017ffd > [ 384.637774] x5 : ffff401ee09a3490 x4 : 0000000000000001 x3 : ffff867522f0c000 > [ 384.644898] x2 : ffff401ee09a3498 x1 : ffff07ffb53cc000 x0 : 0000000000000026 > [ 384.652022] Call trace: > [ 384.654457] sub_running_bw.isra.0+0x190/0x1a0 > [ 384.658890] migrate_task_rq_dl+0xf8/0x1e0 > [ 384.662975] set_task_cpu+0xa8/0x1f0 > [ 384.666540] try_to_wake_up+0x150/0x3d4 > [ 384.670365] wake_up_q+0x64/0xc0 > [ 384.673582] __up_write+0xd0/0x1c0 > [ 384.676974] up_write+0x4c/0x2b0 > [ 384.680191] cppc_set_perf+0x120/0x2d0 > [ 384.683931] cppc_cpufreq_set_target+0xe0/0x1a4 [cppc_cpufreq] > [ 384.689756] __cpufreq_driver_target+0x74/0x140 > [ 384.694277] sugov_work+0x64/0x80 > [ 384.697580] kthread_worker_fn+0xe0/0x230 > [ 384.701580] kthread+0x138/0x140 > [ 384.704797] ret_from_fork+0x10/0x18 Don't quite get this. `sugov:112` should be a special DL entity (dl_se->flags & SCHED_FLAG_SUGOV) so sub_running_bw() should not call __sub_running_bw() and hence there won't be a call to cpufreq_update_util() which calls q_clock(rq) -> assert_clock_updated()? Can't reproduce it on my Juno (arm64) (slow-switching (scpi-cpufreq driver)).