From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932229AbdJVVnJ (ORCPT ); Sun, 22 Oct 2017 17:43:09 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:45428 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932120AbdJVVnH (ORCPT ); Sun, 22 Oct 2017 17:43:07 -0400 Message-Id: <20171022214051.846964231@linutronix.de> User-Agent: quilt/0.63-1 Date: Sun, 22 Oct 2017 23:39:43 +0200 From: Anna-Maria Gleixner To: LKML Cc: Thomas Gleixner , Peter Zijlstra , Ingo Molnar , keescook@chromium.org, Christoph Hellwig , John Stultz Subject: [PATCH v2 05/37] hrtimer: Ensure POSIX compliance (relative CLOCK_REALTIME hrtimers) References: <20171022213938.940451689@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=hrtimer--Fix-Posix-compliance--relative-CLOCK_REALTIME-hrtimers-.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org POSIX specification defines, that relative CLOCK_REALTIME timers are not affected by clock modifications. Those timers have to use CLOCK_MONOTONIC to ensure POSIX compliance. The introduction of the additional mode HRTIMER_MODE_PINNED broke this requirement for pinned timers. There is no user space visible impact because user space timers are not using the pinned mode, but for consistency reasons this needs to be fixed. Check whether the mode has the HRTIMER_MODE_REL bit set instead of comparing with HRTIMER_MODE_ABS. Fixes: 597d0275736d ("timers: Framework for identifying pinned timers") Signed-off-by: Anna-Maria Gleixner --- kernel/time/hrtimer.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1104,7 +1104,12 @@ static void __hrtimer_init(struct hrtime cpu_base = raw_cpu_ptr(&hrtimer_bases); - if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS) + /* + * Posix magic: Relative CLOCK_REALTIME timers are not affected by + * clock modifications, so they needs to become CLOCK_MONOTONIC to + * ensure Posix compliance. + */ + if (clock_id == CLOCK_REALTIME && mode & HRTIMER_MODE_REL) clock_id = CLOCK_MONOTONIC; base = hrtimer_clockid_to_base(clock_id);