From patchwork Mon Jun 10 16:31:11 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Mammedov X-Patchwork-Id: 2698411 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 33A3EDF264 for ; Mon, 10 Jun 2013 16:32:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752549Ab3FJQbo (ORCPT ); Mon, 10 Jun 2013 12:31:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20346 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751489Ab3FJQbn (ORCPT ); Mon, 10 Jun 2013 12:31:43 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r5AGVgSI032754 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 10 Jun 2013 12:31:42 -0400 Received: from dell-pet610-01.lab.eng.brq.redhat.com (dell-pet610-01.lab.eng.brq.redhat.com [10.34.42.20]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r5AGVeY2007628; Mon, 10 Jun 2013 12:31:41 -0400 From: Igor Mammedov To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, mtosatti@redhat.com, eabatalov89@gmail.com Subject: [PATCH] x86: kvmclock: zero initialize pvclock shared memory area Date: Mon, 10 Jun 2013 18:31:11 +0200 Message-Id: <1370881871-13130-1-git-send-email-imammedo@redhat.com> In-Reply-To: References: X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org === Could be the following an acceptable fix? === kernel might hung in pvclock_clocksource_read() due to uninitialized memory might contain odd version value in following cycle: do { version = __pvclock_read_cycles(src, &ret, &flags); } while ((src->version & 1) || version != src->version); if secondary kvmclock is accessed before it's registered with kvm. Clear garbage in pvclock shared memory area right after it's allocated to avoid this issue. Ref: https://bugzilla.kernel.org/show_bug.cgi?id=59521 Signed-off-by: Igor Mammedov --- arch/x86/kernel/kvmclock.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index d2c3812..3dd37eb 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -242,6 +242,7 @@ void __init kvmclock_init(void) if (!mem) return; hv_clock = __va(mem); + memset(hv_clock, 0, size); if (kvm_register_clock("boot clock")) { hv_clock = NULL;