From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754928Ab2DEQLl (ORCPT ); Thu, 5 Apr 2012 12:11:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42341 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752507Ab2DEQLk (ORCPT ); Thu, 5 Apr 2012 12:11:40 -0400 Message-ID: <4F7DC40F.5000805@redhat.com> Date: Thu, 05 Apr 2012 19:10:55 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120316 Thunderbird/11.0 MIME-Version: 1.0 To: Gleb Natapov CC: Sasha Levin , Marcelo Tosatti , Thomas Gleixner , Peter Zijlstra , Ingo Molnar , "Paul E. McKenney" , kvm , linux-kernel , Dave Jones Subject: Re: kvm: RCU warning in async pf References: <1333414472.11455.7.camel@lappy> <20120403105226.GF14939@redhat.com> <20120404123033.GD11918@redhat.com> In-Reply-To: <20120404123033.GD11918@redhat.com> 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 04/04/2012 03:30 PM, Gleb Natapov wrote: > On Tue, Apr 03, 2012 at 01:52:26PM +0300, Gleb Natapov wrote: > > On Mon, Apr 02, 2012 at 08:54:32PM -0400, Sasha Levin wrote: > > > Hi all, > > > > > > I got the spew at the bottom of the mail in a KVM guest using the KVM tools and running trinity. > > > > > > I'm not quite sure how default_idle managed to trigger a pagefault, so that part looks odd to me. > > > > > This is not regular page fault. This is async page fault that tells the > > guest that a page, previously swapped out by hypervisor, is now swapped > > back in and it can happen while vcpu is idle. The code does not leave > > idle state properly though. We probably need to call rcu_irq_enter() > > there. Will look into it. > > > > The patch below solves it for me: > > "Page ready" async PF can kick vcpu out of idle state much like IRQ. > We need to tell RCU about this. > > Applied it, thanks. -- error compiling committee.c: too many arguments to function