From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752981AbbFARCg (ORCPT ); Mon, 1 Jun 2015 13:02:36 -0400 Received: from mail-ig0-f173.google.com ([209.85.213.173]:35100 "EHLO mail-ig0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751888AbbFARC2 (ORCPT ); Mon, 1 Jun 2015 13:02:28 -0400 MIME-Version: 1.0 In-Reply-To: <556C48BD.9010201@redhat.com> References: <1432931068-4980-1-git-send-email-john.stultz@linaro.org> <556C48BD.9010201@redhat.com> Date: Mon, 1 Jun 2015 10:02:27 -0700 Message-ID: Subject: Re: [RFC][PATCH 0/4] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers From: John Stultz To: Prarit Bhargava Cc: lkml , Daniel Bristot de Oliveira , Richard Cochran , Jan Kara , Jiri Bohac , Thomas Gleixner , Ingo Molnar , Shuah Khan Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 1, 2015 at 4:57 AM, Prarit Bhargava wrote: > > > On 05/29/2015 04:24 PM, John Stultz wrote: >> As Prarit reported here: >> https://lkml.org/lkml/2015/5/27/458 >> >> Since the leapsecond is applied at timer tick time, and not >> the actual second edge, ABS_TIME CLOCK_REALTIME timers set for >> right after the leapsecond could fire a second early, since >> some timers may be expired before we trigger the timekeeping >> timer, which then applies the leapsecond. >> >> Thus this patch series tries to address this isssue, including >> extending the leap-a-day test to catch this problem, as well >> as other relevant fixups I found while working on the code. >> >> This series has only had limited testing, so I wanted to send >> it out for initial review and comment. Folks can grab this tree >> via git for testing here: >> https://git.linaro.org/people/john.stultz/linux.git dev/early-leap-timer >> > > John, native testing went well across many 32-bit and 64-bit AMD and Intel > boxes. However, virtual (specifically KVM) guests failed with some sort of > corruption: > > [ 1546.038479] Clock: inserting leap second 23:59:60 UTC > [ 1559.774700] Clock: inserting leap second 23:59:60 UTC > [ 1573.502989] Clock: inserting leap second 23:59:60 UTC > [ 1587.235917] Clock: inserting leap second 23:59:60 UTC > [ 7. X] Clock: inserting leap second 23:59:60 UTC > [ 7. X] Clock: inserting leap second 23:59:60 UTC > [ 7. X] Clock: inserting leap second 23:59:60 UTC > [ 7. X] Clock: inserting leap second 23:59:60 UTC > > I'm going to see if I can figure out a way to kdump a guest with this problem. > The issue is that it seems like all input to the console is ignored when this > happens. Hrm. Can you send me the qemu version and command line you're using? thanks -john