Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754957AbbGCPyE (ORCPT ); Fri, 3 Jul 2015 11:54:04 -0400 Received: from www.linutronix.de ([62.245.132.108]:48919 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755521AbbGCPx4 (ORCPT ); Fri, 3 Jul 2015 11:53:56 -0400 Date: Fri, 3 Jul 2015 17:53:38 +0200 (CEST) From: Thomas Gleixner To: Wolfram Sang cc: Simon Horman , Kevin Hilman , Tyler Baker , Borislav Petkov , Geert Uytterhoeven , Magnus Damm , linux-sh@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: Possible regression due to "tick: broadcast: Prevent livelock from event handler" In-Reply-To: <20150703154036.GD19284@katana> Message-ID: References: <20150703024044.GB24695@verge.net.au> <20150703105441.GF1521@katana> <20150703133245.GA19284@katana> <20150703143703.GB19284@katana> <20150703150951.GC19284@katana> <20150703154036.GD19284@katana> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) 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: 1356 Lines: 37 On Fri, 3 Jul 2015, Wolfram Sang wrote: > > Ok. One more check please. Does nohz=off on the command line fix/hide > > the issue as well? > > Yes, it does. It boots to the prompt then. So something is fishy with this timer. In your UP setting we don't have any interaction with the broadcast stuff. It's just the single em_sti timer involved. Now looking at the code I notice, that this is one of the overly clever designed compare register based trainwrecks. Can you try the patch below, whether it makes a difference? Thanks, tglx --- diff --git a/drivers/clocksource/em_sti.c b/drivers/clocksource/em_sti.c index dc3c6ee04aaa..41d8035d294e 100644 --- a/drivers/clocksource/em_sti.c +++ b/drivers/clocksource/em_sti.c @@ -308,7 +308,7 @@ static void em_sti_register_clockevent(struct em_sti_priv *p) dev_info(&p->pdev->dev, "used for clock events\n"); /* Register with dummy 1 Hz value, gets updated in ->set_mode() */ - clockevents_config_and_register(ced, 1, 2, 0xffffffff); + clockevents_config_and_register(ced, 1, 100, 0xffffffff); } static int em_sti_probe(struct platform_device *pdev) -- 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/