From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932599Ab3E0Ni2 (ORCPT ); Mon, 27 May 2013 09:38:28 -0400 Received: from www.linutronix.de ([62.245.132.108]:47407 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932356Ab3E0Ni0 (ORCPT ); Mon, 27 May 2013 09:38:26 -0400 Date: Mon, 27 May 2013 15:38:19 +0200 (CEST) From: Thomas Gleixner To: Borislav Petkov cc: Meelis Roos , Linux Kernel list , Frederic Weisbecker , Len Brown , "Rafael J. Wysocki" Subject: Re: 3.10-rc3: WARNING: at kernel/time/tick-broadcast.c:578 In-Reply-To: <20130527123520.GA4806@pd.tnic> Message-ID: References: <20130527123520.GA4806@pd.tnic> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 27 May 2013, Borislav Petkov wrote: > On Mon, May 27, 2013 at 02:09:33PM +0300, Meelis Roos wrote: > > I enabled the new full dynctick on one of my test PCs - Intel 815 > > Do you mean CONFIG_NO_HZ_FULL? If so, it is not enabled in the .config > below. > > > chipset single-CPU P3 1 GHz. Got a warning from tick-broadcast.c:578 but > > othwerise it seems to work so far. Full dmesg and config are below. > > Also, there are a bunch of timers fixes from Thomas in tip - you could > try to merge tip/master ontop of -rc3 and retest. All related fixes are already in Linus tree. > > [ 3.872061] ------------[ cut here ]------------ > > [ 3.872161] WARNING: at kernel/time/tick-broadcast.c:578 tick_broadcast_oneshot_control+0x181/0x190() > > [ 3.872258] Modules linked in: ac97_bus snd_pcm snd_page_alloc sg snd_seq uhci_hcd ehci_hcd usbcore microcode snd_seq_device sr_mod snd_timer parport_pc ns558 cdrom snd parport usb_common evdev i2c_i801 gameport pcspkr soundcore rng_core processor button > > [ 3.872726] CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0-rc3 #2 > > [ 3.872785] Hardware name: Packard Bell NEC 00000000000000000000000/i815 , BIOS 2.0Q 09/27/2001 > > [ 3.872892] 00000000 00000000 c1447e74 c134c98c c1447e9c c102877f c13e47ea c13e58c8 > > [ 3.873063] 00000242 c1059aa1 c1059aa1 00200002 c14716a0 c145ce00 c1447eac c10287bb > > [ 3.873234] 00000009 00000000 c1447ecc c1059aa1 00000001 00200046 c14524c0 00000004 > > [ 3.873405] Call Trace: > > [ 3.873467] [] dump_stack+0x16/0x18 > > [ 3.873527] [] warn_slowpath_common+0x5f/0x80 > > [ 3.873588] [] ? tick_broadcast_oneshot_control+0x181/0x190 > > [ 3.873650] [] ? tick_broadcast_oneshot_control+0x181/0x190 > > [ 3.873713] [] warn_slowpath_null+0x1b/0x20 > > [ 3.873772] [] tick_broadcast_oneshot_control+0x181/0x190 > > [ 3.873835] [] tick_notify+0x287/0x3b0 > > [ 3.873903] [] notifier_call_chain+0x40/0x60 > > [ 3.873965] [] __raw_notifier_call_chain+0x19/0x20 > > [ 3.874027] [] raw_notifier_call_chain+0x1a/0x20 > > [ 3.874089] [] clockevents_notify+0x2a/0x120 > > [ 3.874158] [] ? menu_select+0x274/0x5d0 > > [ 3.874227] [] lapic_timer_state_broadcast+0x2e/0x31 [processor] > > [ 3.874293] [] acpi_idle_enter_simple+0x4a/0xb0 [processor] > > [ 3.874357] [] cpuidle_enter_state+0x35/0xc0 > > [ 3.874420] [] cpuidle_idle_call+0x7c/0x130 That brilliant cpuidle stuff calls clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER) twice. So what happens is: CPU0 CPU1 cpuidle_idle_call() clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER) set cpu in tick_broadcast_oneshot_mask broadcast interrupt event expired for cpu1 set pending bit acpi_idle_enter_simple() clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER) WARN_ON(pending bit) So we need to move the WARN_ON into the section where we actually set the broadcast stuff up. diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 24938d5..ec21dc0 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -575,8 +575,8 @@ void tick_broadcast_oneshot_control(unsigned long reason) raw_spin_lock_irqsave(&tick_broadcast_lock, flags); if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) { - WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask)); if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) { + WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask)); clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN); /* * We only reprogram the broadcast timer if we