From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754315AbeDZIAh (ORCPT ); Thu, 26 Apr 2018 04:00:37 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:42790 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753852AbeDZIAe (ORCPT ); Thu, 26 Apr 2018 04:00:34 -0400 From: "Rafael J. Wysocki" To: Thomas Gleixner Cc: Linus Torvalds , Mark Salyzyn , Ingo Molnar , Peter Zijlstra , John Stultz , Peter Anvin , Michael Kerrisk , Prarit Bhargava , Steven Rostedt , Pavel Machek , Kevin Easton , Dmitry Torokhov , Petr Mladek , Linux Kernel Mailing List , SergeySenozhatsky , Jonathan Corbet , linux-tip-commits@vger.kernel.org, Mike Galbraith Subject: Re: [tip:timers/urgent] Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME Date: Thu, 26 Apr 2018 10:00:22 +0200 Message-ID: <1937172.K7anUBJQAz@aspire.rjw.lan> In-Reply-To: <2814513.Yf7f2L7MUC@aspire.rjw.lan> References: <2814513.Yf7f2L7MUC@aspire.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, April 25, 2018 11:28:27 PM CEST Rafael J. Wysocki wrote: > On Wednesday, April 25, 2018 9:09:29 PM CEST Thomas Gleixner wrote: > > On Wed, 25 Apr 2018, Linus Torvalds wrote: > > > On Wed, Apr 25, 2018 at 6:45 AM, tip-bot for Thomas Gleixner > > > wrote: > > > > > > > > As stated in the pull request for the unification of CLOCK_MONOTONIC and > > > > CLOCK_BOOTTIME, it was clear that we might have to revert the change. > > > > > > I'm ok with the revert., but I do want the revert message to talk > > > about *exactly* what broke. > > > > > > I don't see the reported watchdog things, and I run systemd and I ran > > > these patches. > > > > With suspend/resume? > > > > > So it's not just "systemd uses this for a watchdog". It must be > > > something specific that made it trigger for some people and not > > > others, and it's that specific thing that we should document so that > > > we know why this simplification failed. > > > > Fair enough. Do the reporters have more information or do I have to chase > > it down myself? > > Well, if CLOCK_MONOTONIC did not count when the system was suspended and now > it does that due to the change in question, then this is a significant > difference in behavior likely to confuse things even in principle. FWIW, here's a list of issues reported and narrowed down to the commit in question so far I could find: * systemd kills daemons on resume, after >WatchdogSec seconds of suspending (Genki Sky). [Verified that that's because systemd uses CLOCK_MONOTONIC and expects it to not include the suspend time.] * systemd-journald misbehaves after resume: systemd-journald[7266]: File /var/log/journal/016627c3c4784cd4812d4b7e96a34226/system.journal corrupted or uncleanly shut down, renaming and replacing. ( Mike Galbraith). * NetworkManager reports "networking disabled" and networking is broken after resume 50% of the time (Pavel). [May be because of systemd.] * MATE desktop dims the display and starts the screensaver right after system resume (Pavel). * Full system hang during resume (me). [May be due to systemd or NM or both.] I'm not sure if all of the above can be connected to one specific thing (other than the fact that things get confused if they expect CLOCK_MONOTONIC to not include system suspend time).