From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754549Ab1FCLwV (ORCPT ); Fri, 3 Jun 2011 07:52:21 -0400 Received: from mo-p00-ob.rzone.de ([81.169.146.160]:59306 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754401Ab1FCLwU (ORCPT ); Fri, 3 Jun 2011 07:52:20 -0400 X-RZG-AUTH: :IGUXYVOIf/Z0yAghYbpIhzghmj8icP68r1arC3zTx2B9G7/f7yb6+x1CF1B3oIP27v4= X-RZG-CLASS-ID: mo00 Message-ID: <4DE8CAE6.7050002@die-jansens.de> Date: Fri, 03 Jun 2011 13:52:06 +0200 From: Arne Jansen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110424 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: Peter Zijlstra CC: Linus Torvalds , mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, efault@gmx.de, npiggin@kernel.dk, akpm@linux-foundation.org, frank.rowand@am.sony.com, tglx@linutronix.de, mingo@elte.hu, linux-tip-commits@vger.kernel.org Subject: Re: [tip:sched/locking] sched: Add p->pi_lock to task_rq_lock() References: <20110405152729.232781355@chello.nl> <4DE64596.5010006@die-jansens.de> <1306946120.2497.606.camel@laptop> <4DE674EB.1000200@die-jansens.de> <1306951751.2497.626.camel@laptop> <1306953870.2497.627.camel@laptop> <4DE6936F.7090700@die-jansens.de> <1307092535.2353.2973.camel@twins> <4DE8B13D.9020302@die-jansens.de> <1307097052.2353.3061.camel@twins> In-Reply-To: <1307097052.2353.3061.camel@twins> X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03.06.2011 12:30, Peter Zijlstra wrote: > On Fri, 2011-06-03 at 12:02 +0200, Arne Jansen wrote: >> On 03.06.2011 11:15, Peter Zijlstra wrote: > > Bummer. > >> but the hang is not as complete as I first >> thought. A running iostat via ssh continues to give output for a while, >> the serial console still reacts to return and prompts for login. But >> after a while more and more locks up. The console locks as soon as I >> sysrq-t. > > OK, that seems to suggest one CPU is stuck, and once you try something > that touches the CPU everything grinds to a halt. Does something like > sysrq-l work? That would send NMIs to the other CPUs. > > Anyway, good to know using serial doesn't make it go away, that means > its not too timing sensitive. > > >> Also the 10k-print gets triggered >> several times (though I only see 10 lines of output). Maybe you can >> send me your test-module and I'll try that, so we have more equal >> conditions. > > Sure, see below. > Your module also triggers it. On first test directly on first try, on second test only on the 3rd try. When it hangs sysrq-l doesn't give any output. I double checked without a hang, and then it dumps something. >> What also might help: the maschine I'm testing with is a quad-core >> X3450 with 8GB RAM. > > /me & wikipedia, that's a nehalem box, ok I'm testing on a westmere > (don't have a nehalem). > > --- > kernel/Makefile | 1 + > kernel/test.c | 23 +++++++++++++++++++++++ > 2 files changed, 24 insertions(+), 0 deletions(-) > > diff --git a/kernel/Makefile b/kernel/Makefile > index 2d64cfc..65eff6c 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -80,6 +80,7 @@ obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o > obj-$(CONFIG_GENERIC_HARDIRQS) += irq/ > obj-$(CONFIG_SECCOMP) += seccomp.o > obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o > +obj-m += test.o > obj-$(CONFIG_TREE_RCU) += rcutree.o > obj-$(CONFIG_TREE_PREEMPT_RCU) += rcutree.o > obj-$(CONFIG_TREE_RCU_TRACE) += rcutree_trace.o > diff --git a/kernel/test.c b/kernel/test.c > index e69de29..8005395 100644 > --- a/kernel/test.c > +++ b/kernel/test.c > @@ -0,0 +1,23 @@ > +#include > +#include > + > +MODULE_LICENSE("GPL"); > + > +static void > +test_cleanup(void) > +{ > +} > + > +static int __init > +test_init(void) > +{ > + int i; > + > + for (i = 0; i < 10000; i++) > + printk("test %d\n", i); > + > + return 0; > +} > + > +module_init(test_init); > +module_exit(test_cleanup); >