From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757977Ab2CBVML (ORCPT ); Fri, 2 Mar 2012 16:12:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:16735 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756152Ab2CBVMJ (ORCPT ); Fri, 2 Mar 2012 16:12:09 -0500 Date: Fri, 2 Mar 2012 16:11:56 -0500 From: Don Zickus To: Seiji Aguchi Cc: "x86@kernel.org" , LKML , Peter Zijlstra , "tony.luck@intel.com" , "ak@linux.intel.com" , "mjg@redhat.com" , "levinsasha928@gmail.com" Subject: Re: [PATCH 1/2] x86, reboot: revert stop_other_cpus to using IRQ with NMI fallback Message-ID: <20120302211156.GM3083@redhat.com> References: <1329164860-668-1-git-send-email-dzickus@redhat.com> <1329164860-668-2-git-send-email-dzickus@redhat.com> <5C4C569E8A4B9B42A84A977CF070A35B2DACAECA8F@USINDEVS01.corp.hds.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2DACAECA8F@USINDEVS01.corp.hds.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 02, 2012 at 03:41:57PM -0500, Seiji Aguchi wrote: > > > + /* if the REBOOT_VECTOR didn't work, try with the NMI */ > > + if ((num_online_cpus() > 1) && (!smp_no_nmi_ipi)) { > > + if (register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback, > > + NMI_FLAG_FIRST, "smp_stop")) > > register_nmi_handler() doesn't work if kernel panics in nmi context because kzalloc() is called in register_nmi_handler() and > it may sleep. > > register_nmi_handler() should be replaced with notifier_chain like kdump does. I don't think kdump uses the notifier_chain. Cheers, Don