From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759450Ab2CUQas (ORCPT ); Wed, 21 Mar 2012 12:30:48 -0400 Received: from casper.infradead.org ([85.118.1.10]:53633 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758412Ab2CUQaq convert rfc822-to-8bit (ORCPT ); Wed, 21 Mar 2012 12:30:46 -0400 Message-ID: <1332347432.18960.497.camel@twins> Subject: Re: Regression in v3.4-rc0 " BUG: soft lockup - CPU#0 stuck for 29s! [migration/0:6]..[] stop_machine_cpu_stop+0x7b/0xf" From: Peter Zijlstra To: Konrad Rzeszutek Wilk Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@elte.hu, gregkh@linuxfoundation.org, rjw@sisk.pl Date: Wed, 21 Mar 2012 17:30:32 +0100 In-Reply-To: <1332345420.18960.495.camel@twins> References: <20120320235322.GA5416@phenom.dumpdata.com> <20120321152649.GA32737@phenom.dumpdata.com> <1332345420.18960.495.camel@twins> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-03-21 at 16:57 +0100, Peter Zijlstra wrote: > On Wed, 2012-03-21 at 11:26 -0400, Konrad Rzeszutek Wilk wrote: > > On Tue, Mar 20, 2012 at 07:53:22PM -0400, Konrad Rzeszutek Wilk wrote: > > > Seeing this in v3.4-rc0 tree and didn't see that with v3.3: > > > > Hey Peter, > > > > Git bisection points this to the fault of > > 5fbd036b552f633abb394a319f7c62a5c86a9cd7 " sched: Cleanup cpu_active madness" > > > > thoughts? (also attaching the .config) > > Argh.. so when is this? boot? No that's somewhat unexpected. I have one > report of funnies during a hotplug bash that I'm looking into, but I > haven't actually been able to reproduce that report myself either. is arch/x86/xen/smp.c:cpu_bringup() missing a call to notify_cpu_starting() before doing set_cpu_online()? Also, shouldn't that also take the ipi_call_lock() around setting the cpu online?