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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 AB31AC4321D for ; Fri, 24 Aug 2018 08:01:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59F362157F for ; Fri, 24 Aug 2018 08:01:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59F362157F 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 S1727672AbeHXLfJ (ORCPT ); Fri, 24 Aug 2018 07:35:09 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:39536 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727134AbeHXLfJ (ORCPT ); Fri, 24 Aug 2018 07:35:09 -0400 Received: from p4fea45ac.dip0.t-ipconnect.de ([79.234.69.172] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1ft72G-0002Wn-Ed; Fri, 24 Aug 2018 10:01:36 +0200 Date: Fri, 24 Aug 2018 10:01:35 +0200 (CEST) From: Thomas Gleixner To: Heiner Kallweit cc: Frederic Weisbecker , Anna-Maria Gleixner , Linux Kernel Mailing List , Grygorii Strashko Subject: Re: Fix 80d20d35af1e ("nohz: Fix local_timer_softirq_pending()") may have revealed another problem In-Reply-To: <67ce38dc-1f00-55c6-f9ae-2dec00172cf6@gmail.com> Message-ID: References: <8b93f213-fe67-f132-f3f5-5b17995ec63d@gmail.com> <20180824041245.GA2730@lerouge> <67ce38dc-1f00-55c6-f9ae-2dec00172cf6@gmail.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 24 Aug 2018, Heiner Kallweit wrote: > On 24.08.2018 06:12, Frederic Weisbecker wrote: > > On Thu, Aug 16, 2018 at 08:13:03AM +0200, Heiner Kallweit wrote: > >> Recently I started to get warning "NOHZ: local_softirq_pending 202" and > >> I think it's related to mentioned commit (didn't bisect it yet). > >> See log from suspending. > >> > >> I have no reason to think the fix is wrong, it may just have revealed > >> another issue which existed before and was hidden by the bug. > >> > >> Rgds, Heiner > >> > >> [ 75.073353] random: crng init done > >> [ 75.073402] random: 7 urandom warning(s) missed due to ratelimiting > >> [ 78.619564] PM: suspend entry (deep) > >> [ 78.619675] PM: Syncing filesystems ... done. > >> [ 78.653684] Freezing user space processes ... (elapsed 0.002 seconds) done. > >> [ 78.656094] OOM killer disabled. > >> [ 78.656113] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. > >> [ 78.658177] Suspending console(s) (use no_console_suspend to debug) > >> [ 78.663066] nuvoton-cir 00:07: disabled > >> [ 78.671817] sd 0:0:0:0: [sda] Synchronizing SCSI cache > >> [ 78.672210] sd 0:0:0:0: [sda] Stopping disk > >> [ 78.786651] ACPI: Preparing to enter system sleep state S3 > >> [ 78.789613] PM: Saving platform NVS memory > >> [ 78.789759] Disabling non-boot CPUs ... > >> [ 78.805154] NOHZ: local_softirq_pending 202 > >> [ 78.805182] NOHZ: local_softirq_pending 202 > >> [ 78.807102] smpboot: CPU 1 is now offline > > > > I've tried to reproduce with suspend on disk but got unsuccessful. > > > > A small question as I see someone is having a similar issue with a stable > > release only. On which kernel did you trigger that: upstream or stable? > > > > I'll continue investigating. > > > > Thanks. > > > Affected is recent linux-next, after the commit mentioned in the subject. > I can work around the warning (not sure whether it's a proper fix), > see here: > https://lkml.org/lkml/2018/8/18/272 Can you try the one I posted in this thread: https://lkml.kernel.org/r/alpine.DEB.2.21.1808240851420.1668@nanos.tec.linutronix.de Also below for reference. Thanks, tglx 8<---------------- diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 5b33e2f5c0ed..6aab9d54a331 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -888,7 +888,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) if (unlikely(local_softirq_pending() && cpu_online(cpu))) { static int ratelimit; - if (ratelimit < 10 && + if (ratelimit < 10 && !in_softirq() && (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) { pr_warn("NOHZ: local_softirq_pending %02x\n", (unsigned int) local_softirq_pending());