From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756864Ab2CVJUr (ORCPT ); Thu, 22 Mar 2012 05:20:47 -0400 Received: from merlin.infradead.org ([205.233.59.134]:46040 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751684Ab2CVJUp convert rfc822-to-8bit (ORCPT ); Thu, 22 Mar 2012 05:20:45 -0400 Message-ID: <1332408023.18960.503.camel@twins> Subject: Re: [PATCH] xen/smp: Fix bringup bug in AP code. From: Peter Zijlstra To: Konrad Rzeszutek Wilk Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, rjw@sisk.pl, tglx@linutronix.de, xen-devel@lists.xensource.com Date: Thu, 22 Mar 2012 10:20:23 +0100 In-Reply-To: <1332385449-29281-2-git-send-email-konrad.wilk@oracle.com> References: <1332347541.18960.498.camel@twins> <1332385449-29281-1-git-send-email-konrad.wilk@oracle.com> <1332385449-29281-2-git-send-email-konrad.wilk@oracle.com> 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 23:04 -0400, Konrad Rzeszutek Wilk wrote: > The CPU hotplug code has now a callback to help bring up the CPU. > Without the call we end up getting: Its had this for a while now (since 2008, see e545a614). Its just that generic infrastructure started using it only now. > BUG: soft lockup - CPU#0 stuck for 29s! [migration/0:6] > Modules linked in: > CPU ] Pid: 6, comm: migration/0 Not tainted 3.3.0upstream-01180-ged378a5 #1 Dell Inc. PowerEdge T105 /0RR825 > RIP: e030:[] [] stop_machine_cpu_stop+0x7b/0xf0 > RSP: e02b:ffff8800ceaabdb0 EFLAGS: 00000293 > .. snip.. > Call Trace: > [] ? stop_one_cpu_nowait+0x50/0x50 > [] cpu_stopper_thread+0xf1/0x1c0 > [] ? __schedule+0x3c6/0x760 > [] ? _raw_spin_unlock_irqrestore+0x19/0x30 > [] ? res_counter_charge+0x150/0x150 > [] kthread+0x96/0xa0 > [] kernel_thread_helper+0x4/0x10 > [] ? retint_restore_ar > > This fixes it. > > Suggested-by: Peter Zijlstra > Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Peter Zijlstra