From patchwork Wed Aug 20 20:55:09 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Soren Brinkmann X-Patchwork-Id: 4753951 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 92D4FC033A for ; Wed, 20 Aug 2014 20:56:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A9939200E7 for ; Wed, 20 Aug 2014 20:55:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A432D2015A for ; Wed, 20 Aug 2014 20:55:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752893AbaHTUze (ORCPT ); Wed, 20 Aug 2014 16:55:34 -0400 Received: from mail-pd0-f180.google.com ([209.85.192.180]:54763 "EHLO mail-pd0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752816AbaHTUzc (ORCPT ); Wed, 20 Aug 2014 16:55:32 -0400 Received: by mail-pd0-f180.google.com with SMTP id v10so12559130pde.11 for ; Wed, 20 Aug 2014 13:55:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:mime-version:content-type :content-transfer-encoding; bh=0vwe7oshVfCGsrLL0NDbXE9FaACksvXWnnCc3F8a0KM=; b=s5oqGhh0GjWq8F99MJiJazXvFuI5usOPzGkMheuWZCRGFPR/GOzik/THsXm4UDvEVj rmP0Le5gHCr/1Fs5uKHbsujx5mhO2x6pV2arLw33JwqF2C/8CzRKyKy2K+7haVBXBfF2 VCSWgOq6E4KpnvZZQGkJzIlCI6GdqlipcMEDe47qSSg6seiTVJQKrZLTJ10TmsuPgcrg TuqsaCpC3N7ploSxz5bybDTBXfvEug09c6mx3OPbtLcfHP31V+Hp7NhpM/b3Zgm+DJmD URw2v2BHkkqlvblgzn+Rnfdeuw5wnfQpZZrNaezRRQSrVYLKyLfMPWRUVrgvibzcA8Qr yk8w== X-Received: by 10.66.139.36 with SMTP id qv4mr56673694pab.53.1408568129727; Wed, 20 Aug 2014 13:55:29 -0700 (PDT) Received: from localhost ([149.199.62.254]) by mx.google.com with ESMTPSA id po10sm43225712pac.9.2014.08.20.13.55.28 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Wed, 20 Aug 2014 13:55:28 -0700 (PDT) From: Soren Brinkmann To: John Stultz , Thomas Gleixner , "Rafael J. Wysocki" , Pavel Machek , Len Brown Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Daniel Lezcano , Stephen Boyd , Soren Brinkmann Subject: [PATCH] PM / sleep: Fix racing timers Date: Wed, 20 Aug 2014 13:55:09 -0700 Message-Id: <1408568109-30297-1-git-send-email-soren.brinkmann@xilinx.com> X-Mailer: git-send-email 2.0.1.1.gfbfc394 MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On platforms that do not power off during suspend, successfully entering suspend races with timers. The race happening in a couple of location is: 1. disable IRQs (e.g. arch_suspend_disable_irqs()) ... 2. syscore_suspend() -> timekeeping_suspend() -> clockevents_notify(SUSPEND) -> tick_suspend() (timers are turned off here) ... 3. wfi (wait for wake-IRQ here) Between steps 1 and 2 the timers can still generate interrupts that are not handled and stay pending until step 3. That pending IRQ causes an immediate - spurious - wake. The solution is to move the clockevents suspend/resume notification out of the syscore_suspend step and explictly call them at the appropriate time in the suspend/hibernation paths. I.e. timers are suspend _before_ IRQs get disabled. And accordingly in the resume path. Signed-off-by: Soren Brinkmann --- Hi, there was a little of an dicussion on the RFC for this patch, but that eventually ended (https://lkml.org/lkml/2014/7/21/493). In the meantime I found one small flaw that is fixed in this patch (changelog below). This resolves the issues I see on my Zynq (ARM) platform and I also patched my Laptop's (x86_64) kernel with this where it looks good as well. Though, in both cases only suspend is used. Any testing - especially of hibernation - would be much appreciated. Thanks, Sören Changes since RFC: - remove resume notification from syscore_resume path. --- kernel/power/hibernate.c | 9 +++++++++ kernel/power/suspend.c | 5 +++++ kernel/time/timekeeping.c | 3 --- 3 files changed, 14 insertions(+), 3 deletions(-) diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index a9dfa79b6bab..76f15644aec8 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -285,6 +285,8 @@ static int create_image(int platform_mode) if (error || hibernation_test(TEST_CPUS)) goto Enable_cpus; + clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); + local_irq_disable(); error = syscore_suspend(); @@ -316,6 +318,7 @@ static int create_image(int platform_mode) syscore_resume(); Enable_irqs: + clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); local_irq_enable(); Enable_cpus: @@ -438,6 +441,8 @@ static int resume_target_kernel(bool platform_mode) if (error) goto Enable_cpus; + clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); + local_irq_disable(); error = syscore_suspend(); @@ -472,6 +477,7 @@ static int resume_target_kernel(bool platform_mode) syscore_resume(); Enable_irqs: + clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); local_irq_enable(); Enable_cpus: @@ -550,6 +556,8 @@ int hibernation_platform_enter(void) if (error) goto Platform_finish; + clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); + local_irq_disable(); syscore_suspend(); if (pm_wakeup_pending()) { @@ -563,6 +571,7 @@ int hibernation_platform_enter(void) Power_up: syscore_resume(); + clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); local_irq_enable(); enable_nonboot_cpus(); diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 6dadb25cb0d8..6bba2f907bcb 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -294,6 +295,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) if (error || suspend_test(TEST_CPUS)) goto Enable_cpus; + clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); + arch_suspend_disable_irqs(); BUG_ON(!irqs_disabled()); @@ -311,6 +314,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) syscore_resume(); } + clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); + arch_suspend_enable_irqs(); BUG_ON(irqs_disabled()); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index fb4a9c2cf8d9..f13332185b07 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1188,8 +1188,6 @@ static void timekeeping_resume(void) touch_softlockup_watchdog(); - clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); - /* Resume hrtimers */ hrtimers_resume(); } @@ -1242,7 +1240,6 @@ static int timekeeping_suspend(void) write_seqcount_end(&tk_core.seq); raw_spin_unlock_irqrestore(&timekeeper_lock, flags); - clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); clocksource_suspend(); clockevents_suspend();