From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754340Ab2DSCsA (ORCPT ); Wed, 18 Apr 2012 22:48:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55616 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753529Ab2DSCr7 (ORCPT ); Wed, 18 Apr 2012 22:47:59 -0400 Date: Wed, 18 Apr 2012 23:42:44 -0300 From: Marcelo Tosatti To: Avi Kivity Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, davej@redhat.com Subject: Re: [PATCH 3.4-rc] KVM: VMX: Fix kvm_set_shared_msr() called in preemptible context Message-ID: <20120419024244.GD17648@amt.cnet> References: <20120418025822.GA22660@redhat.com> <1334750584-10884-1-git-send-email-avi@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1334750584-10884-1-git-send-email-avi@redhat.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 Wed, Apr 18, 2012 at 03:03:04PM +0300, Avi Kivity wrote: > kvm_set_shared_msr() may not be called in preemptible context, > but vmx_set_msr() does so: > > BUG: using smp_processor_id() in preemptible [00000000] code: qemu-kvm/22713 > caller is kvm_set_shared_msr+0x32/0xa0 [kvm] > Pid: 22713, comm: qemu-kvm Not tainted 3.4.0-rc3+ #39 > Call Trace: > [] debug_smp_processor_id+0xe2/0x100 > [] kvm_set_shared_msr+0x32/0xa0 [kvm] > [] vmx_set_msr+0x28b/0x2d0 [kvm_intel] > ... > > Making kvm_set_shared_msr() work in preemptible is cleaner, but > it's used in the fast path. Making two variants is overkill, so > this patch just disables preemption around the call. > > Reported-by: Dave Jones > Signed-off-by: Avi Kivity > --- > arch/x86/kvm/vmx.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) Applied, thanks.