Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760645Ab3EBVTJ (ORCPT ); Thu, 2 May 2013 17:19:09 -0400 Received: from www.linutronix.de ([62.245.132.108]:41998 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757056Ab3EBVTH (ORCPT ); Thu, 2 May 2013 17:19:07 -0400 Date: Thu, 2 May 2013 23:19:02 +0200 (CEST) From: Thomas Gleixner To: Yinghai Lu cc: Dave Jones , Linux Kernel Subject: Re: clockevents_program_event WARN_ON preventing boot. In-Reply-To: Message-ID: References: <20130430212007.GB18598@redhat.com> <20130430213719.GA14988@redhat.com> <20130502154621.GA23990@redhat.com>

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 Content-Length: 2521 Lines: 70 On Thu, 2 May 2013, Yinghai Lu wrote: > On Thu, May 2, 2013 at 12:58 PM, Thomas Gleixner wrote: > > > > > The check should be: > > > > if (td->evtdev && tick_device_is_functional(td->evtdev)) > > still happens. > > [ 3.457866] checking TSC synchronization [CPU#0 -> CPU#10]: passed. > [ 3.460806] SMP alternatives: lockdep: fixing up alternatives > [ 3.464282] ------------[ cut here ]------------ > [ 3.464297] WARNING: at kernel/time/clockevents.c:209 > clockevents_program_event+0x3b/0x100() I didn't expect it to fix the warning, I just wanted to prevent the crash which Dave decoded. Though the warning and the crash have probably the same root cause... > [ 3.464300] Modules linked in: > [ 3.464306] CPU: 10 PID: 0 Comm: swapper/10 Not tainted > 3.9.0-yh-08066-g1252014-dirty #1537 > [ 3.464308] Hardware name: Oracle Corporation unknown / > , BIOS 11016600 05/17/2011 > [ 3.464327] 0000000000000009 ffff88203e203ed8 ffffffff82091022 > ffff88203e203f18 > [ 3.464343] ffffffff81088990 ffff88203e203f08 80000000003d08ff > 80000000003d08ff > [ 3.464359] 000000000000000a ffff881027557fd8 0000000000000000 > ffff88203e203f28 > [ 3.464361] Call Trace: > [ 3.464379] [] dump_stack+0x19/0x1b > [ 3.464392] [] warn_slowpath_common+0x70/0xa0 > [ 3.464395] [] warn_slowpath_null+0x1a/0x20 > [ 3.464399] [] clockevents_program_event+0x3b/0x100 > [ 3.464403] [] tick_handle_periodic+0x4c/0x80 Now, that's really odd. next = ktime_add(dev->next_event, tick_period); clockevents_program_event(dev, next, false); and next.tv64 is < 0 !?! Can you please apply the following debug patch and provide the output? Thanks, tglx diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index c6d6400..b4d9622 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -207,6 +207,8 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, if (unlikely(expires.tv64 < 0)) { WARN_ON_ONCE(1); + printk_once(KERN_INFO "expires %llx, dev->next %llx\n", + expires.tv64, dev->next_event.tv64); return -ETIME; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/