From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752794Ab2GIJnc (ORCPT ); Mon, 9 Jul 2012 05:43:32 -0400 Received: from terminus.zytor.com ([198.137.202.10]:52358 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751771Ab2GIJna (ORCPT ); Mon, 9 Jul 2012 05:43:30 -0400 Date: Mon, 9 Jul 2012 02:43:01 -0700 From: tip-bot for John Stultz Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, johnstul@us.ibm.com, jengelh@inai.de, tglx@linutronix.de, prarit@redhat.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, johnstul@us.ibm.com, tglx@linutronix.de, jengelh@inai.de, prarit@redhat.com In-Reply-To: <1341515538-5100-2-git-send-email-johnstul@us.ibm.com> References: <1341515538-5100-2-git-send-email-johnstul@us.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/urgent] hrtimer: Fix clock_was_set so it is safe to call from irq context Git-Commit-ID: adf374cf61394dd41c027c74a81f9bef90f7a640 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Mon, 09 Jul 2012 02:43:07 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: adf374cf61394dd41c027c74a81f9bef90f7a640 Gitweb: http://git.kernel.org/tip/adf374cf61394dd41c027c74a81f9bef90f7a640 Author: John Stultz AuthorDate: Thu, 5 Jul 2012 15:12:16 -0400 Committer: Thomas Gleixner CommitDate: Mon, 9 Jul 2012 11:35:38 +0200 hrtimer: Fix clock_was_set so it is safe to call from irq context NOTE: This is a prerequisite patch that's required to address the widely observed leap-second related futex/hrtimer issues. Currently clock_was_set() is unsafe to be called from irq context, as it calls on_each_cpu(). This causes problems when we need to adjust the time from update_wall_time(). To fix this, if clock_was_set is called when irqs are disabled, we schedule a timer to fire for immedately after we're out of interrupt context to then notify the hrtimer subsystem. Reported-by: Jan Engelhardt Signed-off-by: John Stultz Acked-by: Prarit Bhargava CC: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1341515538-5100-2-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner --- kernel/hrtimer.c | 17 ++++++++++++++++- 1 files changed, 16 insertions(+), 1 deletions(-) diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ae34bf5..d730678 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -746,7 +746,7 @@ static inline void retrigger_next_event(void *arg) { } * resolution timer interrupts. On UP we just disable interrupts and * call the high resolution interrupt code. */ -void clock_was_set(void) +static void do_clock_was_set(unsigned long data) { #ifdef CONFIG_HIGH_RES_TIMERS /* Retrigger the CPU local events everywhere */ @@ -755,6 +755,21 @@ void clock_was_set(void) timerfd_clock_was_set(); } +static DEFINE_TIMER(clock_was_set_timer, do_clock_was_set , 0, 0); + +void clock_was_set(void) +{ + /* + * We can't call on_each_cpu() from irq context, + * so if irqs are disabled , schedule the clock_was_set + * via a timer_list timer for right after. + */ + if (irqs_disabled()) + mod_timer(&clock_was_set_timer, jiffies); + else + do_clock_was_set(0); +} + /* * During resume we might have to reprogram the high resolution timer * interrupt (on the local CPU):