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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 0FDDBC433B4 for ; Mon, 17 May 2021 14:35:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA9D761CA6 for ; Mon, 17 May 2021 14:35:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239808AbhEQOg6 (ORCPT ); Mon, 17 May 2021 10:36:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:42578 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239505AbhEQOcV (ORCPT ); Mon, 17 May 2021 10:32:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1621261864; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xYuVntA3/R/ZCitOay3lqoXYi06Ia6ssKRAW0I+ZVEQ=; b=onF0H9B9bQCdRewBj3vytxij9z4KTsIYSNxSqcecKyQPRdrOAi3efgEfmkDESl/9FsDWVo 6+qrRVNjhH/qaue35jXNjD2juuBvyrIgFtkt2fBMIAQAMnidxKaXFBXxmaXC4bwdlogYh9 E+4coHG6PiyCc5dDwMBVb6U+ubsV3Ac= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 03E4EB275; Mon, 17 May 2021 14:31:03 +0000 (UTC) Date: Mon, 17 May 2021 16:30:56 +0200 From: Petr Mladek To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Ingo Molnar , Laurence Oberman , Michal Hocko , Peter Zijlstra , Thomas Gleixner , Vincent Whitchurch , Andrew Morton , Linus Torvalds , Sergey Senozhatsky , Sasha Levin Subject: Re: [PATCH 5.12 123/363] watchdog: cleanup handling of false positives Message-ID: References: <20210517140302.508966430@linuxfoundation.org> <20210517140306.783130885@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210517140306.783130885@linuxfoundation.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2021-05-17 15:59:49, Greg Kroah-Hartman wrote: > From: Petr Mladek > > [ Upstream commit 9bf3bc949f8aeefeacea4b1198db833b722a8e27 ] > > Commit d6ad3e286d2c ("softlockup: Add sched_clock_tick() to avoid kernel > warning on kgdb resume") introduced touch_softlockup_watchdog_sync(). [...] > Make the code more straightforward: > > 1. Always call kvm_check_and_clear_guest_paused() at the very > beginning to handle PVCLOCK_GUEST_STOPPED. It touches the watchdog > when the quest did sleep. > > 2. Handle the situation when the watchdog has been touched > (SOFTLOCKUP_DELAY_REPORT is set). > > Call sched_clock_tick() when touch_*sync() variant was used. It makes > sure that the timestamp will be up to date even when it has been > touched in atomic context or quest did sleep. > > As a result, kvm_check_and_clear_guest_paused() is called on a single > location. And the right timestamp is always set when returning from the > timer callback. > > Link: https://lkml.kernel.org/r/20210311122130.6788-7-pmladek@suse.com Please, remove this patch from the stable backport. It might cause false softlockup reports, see https://lore.kernel.org/r/20210517140612.222750-1-senozhatsky@chromium.org Best Regards, Petr