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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D937C433EF for ; Tue, 8 Feb 2022 07:32:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347016AbiBHHcp (ORCPT ); Tue, 8 Feb 2022 02:32:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbiBHHcm (ORCPT ); Tue, 8 Feb 2022 02:32:42 -0500 Received: from mx1.molgen.mpg.de (mx3.molgen.mpg.de [141.14.17.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 118DAC0401EF for ; Mon, 7 Feb 2022 23:32:41 -0800 (PST) Received: from [192.168.0.2] (ip5f5aebc2.dynamic.kabel-deutschland.de [95.90.235.194]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pmenzel) by mx.molgen.mpg.de (Postfix) with ESMTPSA id 0129961E64846; Tue, 8 Feb 2022 08:32:38 +0100 (CET) Message-ID: <0baca95b-771f-2217-1098-2d0eee568ea7@molgen.mpg.de> Date: Tue, 8 Feb 2022 08:32:37 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Content-Language: en-US To: Frederic Weisbecker , Thomas Gleixner , Ingo Molnar Cc: LKML , linuxppc-dev@lists.ozlabs.org From: Paul Menzel Subject: ppc64le: `NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!!` when turning off SMT Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dear Linux folks, On the POWER8 server IBM S822LC running Ubuntu 21.10, Linux 5.17-rc1+ built with $ grep HZ /boot/config-5.17.0-rc1+ CONFIG_NO_HZ_COMMON=y # CONFIG_HZ_PERIODIC is not set CONFIG_NO_HZ_IDLE=y # CONFIG_NO_HZ_FULL is not set CONFIG_NO_HZ=y # CONFIG_HZ_100 is not set CONFIG_HZ_250=y # CONFIG_HZ_300 is not set # CONFIG_HZ_1000 is not set CONFIG_HZ=250 once warned about a NOHZ tick-stop error, when I executed `sudo /usr/sbin/ppc64_cpu --smt=off` (so that KVM would work). ``` $ dmesg [ 0.000000] Linux version 5.17.0-rc1+ (pmenzel@flughafenberlinbrandenburgwillybrandt.molgen.mpg.de) (Ubuntu clang version 13.0.0-2, LLD 13.0.0) #1 SMP Fri Jan 28 17:13:04 CET 2022 […] [271272.030262] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271272.305726] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271272.549790] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271274.885167] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271275.113896] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271275.412902] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271275.625245] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271275.833107] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271276.041391] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! [271277.244880] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!! ``` Kind regards, Paul