From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751747AbeEMNJ4 (ORCPT ); Sun, 13 May 2018 09:09:56 -0400 Received: from terminus.zytor.com ([198.137.202.136]:43777 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345AbeEMNJz (ORCPT ); Sun, 13 May 2018 09:09:55 -0400 Date: Sun, 13 May 2018 06:09:44 -0700 From: tip-bot for Sudeep Holla Message-ID: Cc: mingo@kernel.org, fweisbec@gmail.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, sudeep.holla@arm.com, hpa@zytor.com Reply-To: hpa@zytor.com, linux-kernel@vger.kernel.org, sudeep.holla@arm.com, fweisbec@gmail.com, tglx@linutronix.de, mingo@kernel.org In-Reply-To: <1525881728-4858-1-git-send-email-sudeep.holla@arm.com> References: <1525881728-4858-1-git-send-email-sudeep.holla@arm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/core] tick: Prefer a lower rating device only if it's CPU local device Git-Commit-ID: 1332a90558013ae4242e3dd7934bdcdeafb06c0d 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 1332a90558013ae4242e3dd7934bdcdeafb06c0d Gitweb: https://git.kernel.org/tip/1332a90558013ae4242e3dd7934bdcdeafb06c0d Author: Sudeep Holla AuthorDate: Wed, 9 May 2018 17:02:08 +0100 Committer: Thomas Gleixner CommitDate: Sun, 13 May 2018 15:07:41 +0200 tick: Prefer a lower rating device only if it's CPU local device Checking the equality of cpumask for both new and old tick device doesn't ensure that it's CPU local device. This will cause issue if a low rating clockevent tick device is registered first followed by the registration of higher rating clockevent tick device. In such case, clockevents_released list will never get emptied as both the devices get selected as preferred one and we will loop forever in clockevents_notify_released. Signed-off-by: Sudeep Holla Signed-off-by: Thomas Gleixner Cc: Frederic Weisbecker Link: https://lkml.kernel.org/r/1525881728-4858-1-git-send-email-sudeep.holla@arm.com --- kernel/time/tick-common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 49edc1c4f3e6..78e598334007 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -277,7 +277,8 @@ static bool tick_check_preferred(struct clock_event_device *curdev, */ return !curdev || newdev->rating > curdev->rating || - !cpumask_equal(curdev->cpumask, newdev->cpumask); + (!cpumask_equal(curdev->cpumask, newdev->cpumask) && + !tick_check_percpu(curdev, newdev, smp_processor_id())); } /*