From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933258Ab3GPPui (ORCPT ); Tue, 16 Jul 2013 11:50:38 -0400 Received: from merlin.infradead.org ([205.233.59.134]:41072 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932590Ab3GPPug (ORCPT ); Tue, 16 Jul 2013 11:50:36 -0400 Date: Tue, 16 Jul 2013 17:48:52 +0200 From: Peter Zijlstra To: Gleb Natapov Cc: Raghavendra K T , mingo@redhat.com, jeremy@goop.org, x86@kernel.org, konrad.wilk@oracle.com, hpa@zytor.com, pbonzini@redhat.com, linux-doc@vger.kernel.org, habanero@linux.vnet.ibm.com, xen-devel@lists.xensource.com, mtosatti@redhat.com, stefano.stabellini@eu.citrix.com, andi@firstfloor.org, attilio.rao@citrix.com, ouyang@cs.pitt.edu, gregkh@suse.de, agraf@suse.de, chegu_vinod@hp.com, torvalds@linux-foundation.org, avi.kivity@gmail.com, tglx@linutronix.de, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stephan.diestelhorst@amd.com, riel@redhat.com, drjones@redhat.com, virtualization@lists.linux-foundation.org, srivatsa.vaddagiri@gmail.com Subject: Re: [PATCH RFC V10 15/18] kvm : Paravirtual ticketlocks support for linux guests running on KVM hypervisor Message-ID: <20130716154852.GN23818@dyad.programming.kicks-ass.net> References: <20130624124014.27508.8906.sendpatchset@codeblue.in.ibm.com> <20130624124342.27508.44656.sendpatchset@codeblue.in.ibm.com> <20130714131241.GA11772@redhat.com> <51E3C5CE.7000009@linux.vnet.ibm.com> <20130715103648.GN11772@redhat.com> <51E4C011.4060803@linux.vnet.ibm.com> <20130716060215.GE11772@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130716060215.GE11772@redhat.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 16, 2013 at 09:02:15AM +0300, Gleb Natapov wrote: > BTW can NMI handler take spinlocks? No -- that is, yes you can using trylock, but you still shouldn't. > If it can what happens if NMI is > delivered in a section protected by local_irq_save()/local_irq_restore()? You deadlock.